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6.7: Exercise 2 - Identifying strains by nutritional requirements - Biology

6.7: Exercise 2 - Identifying strains by nutritional requirements - Biology


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Your team will be given three strains, each of which carries a different met mutation. Each member of the team should prepare serial dilutions of a single strain.

  1. Spot your dilution series on each of the plates that your team received. Spot the complete di- lution on one plate before proceding to the second plate. Use the same pattern of strains/rows on each of the different selective plates. Make sure that the plates are properly labeled!
  2. Incubate the plates at 30 oC until colonies should become apparent. Note that some colonies grow slowly on defined media and may require more than 3 days to appear. When colonies reach the desired size, transfer the plates to the cold room for storage.
  3. Scan the plates as you did in Chapter 4 to record your data. These data will become the focus of your first lab report for the semester. Think of how you would like your figure to look as you place the plates on the scanner.
  • Scan the plates containing variations of YC media together, taking care to orient the plates

    in the same direction.

  • Scan the plate containing BiGGY agar separately using the color settings.

4. Use the predictions from the previous exercise to identify your team’s mutant strains. This information will be compiled into a table in your lab report.

Consult the “Write It Up!” chapter for instructions on preparing lab reports.


Fertilizer Types: 6 Main Types of Fertilizers

The following points highlight the six important types of fertilizers. The types are: 1. Nitrogenous Fertilizers 2. Organic Nitrogenous Fertilizers 3. Phosphate Fertilizers 4. Potassic Fertilizers 5. Compound Fertilizers 6. Complete Fertilizers (NPK).

Type # 1. Nitrogenous Fertilizers:

The nitrogenous fertilizers are divided into four groups — nitrate, ammonia and ammonium salts, chemical compounds containing nitrogen in the amide form, and plant and animal byproducts.

It occurs in natural deposits in northern Chile and is refined before use. The refined product contains about 16% nitrogen in the nitrate form, which renders it directly available to plants. For this reason it is applied as a source of nitrogen, specially to young plants and garden vegetables, which need readily available nitrogen for quick growth.

Sodium nitrate is easily soluble in water and is quickly leached out from the soil. It is particularly useful for acidic soils. Its continued and abundant use in soils causes de-flocculation and develop a bad physical condition in the regions of low rainfall.

It is the most widely used fertilizer in the country. It is a white crystalline salt, containing 20 to 21 % ammoniacal nitrogen. It is very suitable for wet­land crops, for example, paddy and jute. Ammonium sulphate is easy to handle and is stored well under dry conditions.

It is also suitable for wheat, cotton, sugarcane, potatoes and many other crops grown on a wide variety of soils. Its continuous use increases soil acidity and lowers the yield. Its application to acid soils improves the yield of tea plantation considerably. It is advisable to use this fertilizer along with bulky organic manures to avoid its ill effects.

Ammonium sulphate can be applied before sowing, at sowing time, or as a top dressing to the growing crop. It should not be applied during germination, as in concentrated form it affects the germination very adversely.

Ammonium nitrate is a white crystalline salt, containing 33 to 35% nitrogen, 50% as nitrate nitrogen and another 50 percent as the ammonium form. In the ammonium form it is not leached out easily from the soil. It is quick-acting and highly hygroscopic and cannot be stored. Under certain conditions, it is explosive and, therefore, should be handled cautiously.

‘Nitro Chalk’ is the trade name of the product formed by mixing ammonium nitrate with about 40% of limestone or dolomite. It contains 20.5% nitrogen, 50% in the form of ammonia and half as nitrate. Its continuous use makes the soil acidic. The presence of lime makes it useful for acid soils.

(iv) Ammonium Sulphate Nitrate:

It is a mixture of ammonium sulphate and ammonium nitrate. It is available in a white crystalline form or as dirty white granules. It contains 26% nitrogen, three-fourths of it in the ammoniacal form and the rest as nitrate nitrogen.

It highly soluble in water and very quick-acting and non-explosive. It is useful for all crops. It slightly acidifies the soil. It is applied before sowing, during sowing or as a top dressing, but it is unsuitable for application along with the seeds.

It is quite crystalline compound possessing a good physical condition. It contains 26% ammoniacal nitrogen. It is extensively used on paddy in Japan. It is used largely in- industries in India. It is similar to ammonium sulphate in action. It is not recommended for certain types of crops like tomatoes, tobacco, etc., as they may be injured by chlorine.

Urea is a white crystalline organic compound. It is highly concentrated nitrogenous fertilizer containing 45 to 46% of organic nitrogen. It is highly hygroscopic and cannot be stored well in humid regions. To overcome this difficulty it is also produced in granular pellet forms coated with a non-hygroscopic inert material.

It is highly soluble in water and rapidly leached out from the soil. It is very quick-acting and rapidly changed into ammonia when applied. It is applied during sowing or as top-dressing but never during germination. It is suitable for most crops and can be applied to all types of soils.

(vii) Calcium Ammonium Nitrate:

It is a fine, light brown or gray granular fertilizer. It is prepared from ammonium nitrate and ground limestone. It is almost neutral and can be applied even to acid soils. Its nitrogen content varies from 25 to 28 percent. Of the total nitrogen 50 percent remains in the ammoniacal form and the remaining 50 percent in nitrate form.

Type # 2. Organic Nitrogenous Fertilizers:

These fertilizers include plant and animal by-products, such as oil cakes, fish manure and dried blood from slaughter-houses. Before use by the crops these materials are converted by bacterial fermentation into utilizable ammonium-nitrogen and nitrate-nitrogen. These fertilizers are, therefore, slow acting, but supply available nitrogen for a longer period to the crops.

Oil-cakes are usually supplied as organic fertilizer throughout the country. They contain not only nitrogen but also some phosphoric acid and potash. A large quantity of organic matter is also present in the oil-cake. In addition to the three fertilizing constituents like, N, P2O5 and K2O, the oil-cakes contain 2 to 15 percent of oil.

Dried blood or blood meal contains 10 to 12 percent highly available nitrogen and 1 to 2 percent phosphoric acid. It is effective on all types of crops and all types of soils.

Fish manure is available either as dried fish or as fish meal or powder. After extraction of oil from the fish the residue can be used as a manure, Fish manure contains 5 to 8 percent organic nitrogen and 4 to 6 percent of phosphoric acid. It is quick acting and suitable for all crops and soils. It is usually used as powder.

Type # 3. Phosphate Fertilizers:

Phosphate fertilizers are classified as natural phosphates, treated phosphates, by-product phosphates and chemical phosphates.

It occurs as natural deposits of rock in different countries. Very little rock phosphate is used directly as a fertilizer. Much more of it is used to manufacture superphosphate, the phosphoric acid of which is water soluble and becomes available to the crops.

It is the most widely used phosphoric fertilizer in India. It is now manufactured from ground phosphate rocks treating with sulphuric acid. The brownish- gray product after treatment contains mono-calcium phosphate and calcium sulphate (Gypsum) in practically equal quantities.

There are three grades of super phosphate:

Single superphosphate containing 16 to 20 percent phosphoric acid di-calcium phosphate, 35 to 38 percent and triple superphosphate, 44 to 49 percent.

Single superphosphate is the most commonly available grade in Indian market. The fertilizer is suitable for all crops and can be applied to all soils. It should be used along with organic manures in acid soils. It should be applied before or at sowing or transplanting.

Basic slag is a by-product of steel factories. It contains 6 to 20 percent of phosphoric acid (P2O5). The European slag contains 15 to 18 percent P2O5 and used as a popular phosphatic fertilizer in central Europe. But slag from Indian steel mills is poor in P2O5 and is not used as a fertilizer. The European slag is suitable for acid soils as it is alkaline in reaction. For effective use, it must be pulverized before application.

The ground bone is called bone-meal. It is now widely used as phosphate fertilizer.

It is available in two forms:

The steaming up bones under pressure removes fats, nitrogen and glue making substances. It contains 25 to 30 percent phosphoric acid. Steamed bones are more brittle and can be readily ground.

As it is slow acting, bone-meal should not be used as a top dressing. It must be incorporated into the soil in order to become available. It is applied either at sowing time or a few days before sowing and should be broadcast. It is particularly suitable for acid soils.

It is used for all crops. In some places of the country charred and powdered bones are used as manure. Charring destroys about 50 percent of nitrogen, but the whole of P2O5 remains in a quickly available form.

Type # 4. Potassic Fertilizers:

In India most of the soils contain sufficient amount of potash. So, potassic fertilizers are applied only to those soils which are deficient in potash.

Potassic fertilizers are used as:

(a) muriate of potash (potassium chloride)

(b) sulphate of potash (potassium sulphate).

It is a gray crystalline material containing 50 to 63 percent of potash (K2O), the whole of which is available to the crops. It remains absorbed on the colloidal surfaces and is not leached out from the soil. It is applied at sowing time or before sowing.

(ii) Sulphate of Potash:

It is more costly as it is prepared by treating potassium chloride with magnesium sulphate. It contains 48 to 52 percent K2O. It dissolves readily in water and becomes available to the crops almost immediately after application. It can be applied at any time up to sowing. In certain crops like tobacco, chillies, potato and fruit-tree it is considered better than muriate of potash.

Type # 5. Compound Fertilizers:

These fertilizers contain two or three plant nutrients simultaneously. When both nitrogen and phosphorus are deficient in soil, a compound fertilizer, e.g., amorphous, can be used. It contains 16 percent nitrogen and 20 percent P2O5. Two different fertilizers can be mixed in correct proportion to produce the compound fertilizer.

Type # 6. Complete Fertilizer (NPK):

Compound fertilizers are not always well adapted to different kinds of soils. For that reason mixed fertilizers containing two or more materials in suitable proportions are used according to the needs of different soils. Mixtures usually fulfil the nutrient deficiencies in a more balanced manner and require less labour to apply than different fertilizers used separately.

These mixtures containing all the three principal nutrients (N, P and K) are called complete fertilizers as most soils usually remain deficient in these three elements. A special mixture for different crops are also produced by the manufacturers.

In some cases insecticides, fungicides and weed-killers, such as DDT, BHC and mercury or copper salts and 2, 4-D are mixed into the complete fertilizers. The component fertilizers must be compatible to ensure mutual reaction. Uneven mixing must be avoided. Bone- meal, muriate of potash and sulphate of potash can be mixed with all fertilizers.


The Basics of Equine Nutrition

Horses are non-ruminant herbivores (hind-gut fermentors). Their small stomach only has a capacity of 2 to 4 gallons for an average-sized 1000 lb. horse. This limits the amount of feed a horse can take in at one time. Equids have evolved as grazers that spend about 16 hours a day grazing pasture grasses. The stomach serves to secrete hydrochloric acid (HCl) and pepsin to begin the breakdown of food that enters the stomach. Horses are unable to regurgitate food, so if they overeat or eat something poisonous vomiting is not an option.

Horses are also unique in that they do not have a gall bladder. This makes high fat diets hard to digest and utilize. Horses can digest up to 20 % fat in their diet, but it takes a span of 3 to 4 weeks for them to adjust. Normal horse rations contain only 3 to 4 % fat.

The horse’s small intestine is 50 to 70 feet long and holds 10 to 23 gallons. Most of the nutrients (protein, some carbohydrates and fat) are digested in the small intestine. Most of the vitamins and minerals are also absorbed here.

Most liquids are passed to the cecum, which is 3 to 4 feet long and holds 7 to 8 gallons. Detoxification of toxic substances occurs in the cecum. It also contains bacteria and protozoa that pass the small intestine to digest fiber and any soluble carbohydrates.

Photo & Diagram: C. Williams

The large colon, small colon, and rectum make up the large intestine. The large colon is 10 to 12 feet long, and holds 14 to 16 gallons. It consists of four parts: right ventral colon, sternal flexure to left ventral colon, pelvic flexure to left dorsal colon, and diaphragmatic flexure to the right dorsal colon. The sternal and diaphragmatic flexures are a common place for impaction. The small colon leads to the rectum. It is 10 feet long and holds only 5 gallons of material.

Horses require six main classes of nutrients to survive they include water, fats, carbohydrates, protein, vitamins,and minerals.

Water is the MOST IMPORTANT nutrient horses can’t live long without it! Always make sure there is an adequate, clean supply of water. Horses generally drink about 2 quarts of water for every pound of hay they consume. In high temperature, hard work, or for the lactating mare the water requirement may be 3 to 4 times the normal consumption.

Signs that your horse may be water deficient include decreased feed intake and physical activity, and signs of dehydration like dry mucous membranes in the mouth, dry feces, and decreased capillary refill time. Possible causes of water deficiencies include no water source, low water palatability, or accessibility (frozen or receiving or contaminated), or illness.

Energy isn’t one of the six nutrients because the horse cannot physically consume energy, however, it is a requirement for sustaining life. The most dense source of energy is fat (almost three times more than carbohydrates or proteins) however, carbohydrates in the forms of fermentable fiber or starch are the most common source. Horses exercising, growing, pregnant in late gestation or early lactation need increased energy in their diet.

Signs of energy deficiency include weight loss, decreased physical activity, milk production, and growth rate. However, feeding a diet too high in energy can cause obesity increasing the risk of colic, laminitis, and contribute to increased sweat loss and exercise intolerance.

Fat can be added to a feed to increase the energy density of the diet. Fat has 9 Mcal/kg of energy, which is three-times that of any grain or carbohydrate source. Fat is normally found at 2 to 6% in most premixed feeds however, some higher fat feeds will contain 10 to 12% fat. See Fat Supplements section for more.

Carbohydrates are the main energy source used in most feeds. The main building block of carbohydrates is glucose. Soluble carbohydrates such as starches and sugars are readily broken down to glucose in the small intestine and absorbed. Insoluble carbohydrates such as fiber (cellulose) bypass enzymatic digestion and must be fermented by microbes in the large intestine to release their energy sources, the volatile fatty acids. Soluble carbohydrates are found in nearly every feed source corn has the highest amount, then barley and oats. Forages normally have only 6 to 8% starch but under certain conditions can have up to 30%. Sudden ingestion of large amounts of starch or high sugar feeds can cause colic or laminitis.

Protein is used in muscle development during growth or exercise. The main building blocks of protein are amino acids. Soybean meal and alfalfa are good sources of protein that can be easily added to the diet. Second and third cutting alfalfa can be 25 to 30% protein and can greatly impact the total dietary protein. Most adult horses only require 8 to 10% protein in the ration however, higher protein is important for lactating mares and young growing foals.

Signs of protein deficiency include a rough or coarse hair coat, weight loss, and reduced growth, milk production, and performance. Excess protein can result in increased water intake and urination, and increased sweat losses during exercise, which in turn lead to dehydration and electrolyte imbalances.

Vitamins are fat-soluble (vitamin A, D, E, and K), or water-soluble (vitamin C, and B-complex). Horses at maintenance usually have more than adequate amounts of vitamins in their diet if they are receiving fresh green forage and/or premixed rations. Some cases where a horse would need a vitamin supplement include when feeding a high-grain diet, or low-quality hay, if a horse is under stress (traveling, showing, racing, etc.), prolonged strenuous activity, or not eating well (sick, after surgery, etc.).

Most of the vitamins are found in green, leafy forages. Vitamin D is obtained from sunlight, so only horses that are stalled for 24 hours a day need a supplement with vitamin D. Vitamin E is found in fresh green forages, however, the amount decreases with plant maturity and is destroyed during long term storage. Horses that are under heavy exercise or under increased levels of stress also may benefit from vitamin E supplementation. Vitamin K and B-complex are produced by the gut microbes. Vitamin C is found in fresh vegetables and fruits, and produced naturally by the liver. None of these are usually required in a horse’s diet. Severely stressed horses, however, may benefit from B-complex and vitamin C supplements during the period of stress.

Minerals are required for maintenance of body structure, fluid balance in cells (electrolytes), nerve conduction, and muscle contraction. Only small amounts of the macro-minerals such as calcium, phosphorus, sodium, potassium, chloride, magnesium, and sulfur are needed daily.

Calcium and phosphorus are needed in a specific ratio ideally 2:1, but never less than 1:1. Alfalfa alone can exceed a Ca:P ratio of 6:1. Sweating depletes sodium, potassium, and chloride from the horse’s system, therefore, supplementation with electrolytes may be helpful for horses that sweat a lot. Normally, if adult horses are consuming fresh green pasture and/or a premixed ration, they will receive proper amounts of minerals in their diet, with the exception of sodium chloride (salt), which should always be available. Young horses may need added calcium, phosphorus, copper, and zinc during the first year or two of life.

Forages are classified as legumes or grasses. The nutrients in the forage vary greatly with maturity of the grasses, fertilization, management, and environmental conditions. In order to determine the nutrient content in forage it is best to take samples and get them analyzed by a forage testing lab (contact your local County Extension Office for testing information or see the fact sheet, FS714, Analysis of Feeds and Forages for Horses).

Legumes are usually higher in protein, calcium, and energy than grasses. They have more leaves than grasses and require optimal growth conditions (warm weather and good soil) to produce the best nutrients. Some legumes include clover and alfalfa. Some commonly used grasses include orchard grass, timothy, bluegrass, and fescue.

Hay is forage that has been harvested, dried, and baled before feeding to horses. Legume hay can contain 2 to 3 times more protein and calcium than grass hay. However, it is usually more costly. Common grass hays include timothy, brome and orchard grass. They have fine stems, seed heads and longer leaves than legumes. They are most nutritious when cut earlier in their growth stage. Maturity at harvest is key to quality. Second cut grass hays average 16 to 20% protein.

Appearance can be a good indicator of the amount of nutrients in the hay, however, color should not be used as sole indicator. Moldy or dusty hay should not be fed to horses. For more information see Table 1.

Table 1. Evaluating Hay Quality

Low moisture content (12 to 18%).


Sweet smelling, like newly cut grass.


Grass hays before seed heads mature and alfalfa cut early in bloom.


Free from weeds, poisonous plants, trash, or foreign objects.

Damp. Too much moisture causes mold.


Brown, yellow or weathered in color. Gray or black indicates mold.


Musty, moldy or fermented odor.


Dusty and moldy hay is unacceptable.


Cut late in maturity. Mature seed heads with grass hay or alfalfa cut late in bloom.


High weed content, poisonous plants, or animal carcasses in hay bales.

Oats are the most popular grain for horses. Oats have a lower digestible energy value and higher fiber content than most other grains. They are also more palatable and digestible for horses than other grains however, they can be expensive.

Corn is the second most palatable grain for horses. It provides twice as much digestible energy as an equal volume of oats and is low in fiber. Because it is so energy dense it is easy to over feed corn, causing obesity. Moldy corn should never be fed—it is lethal to horses.

Sorghum (Milo) is a small hard kernel that needs to be processed (steam flaked, crushed, etc.) for efficient digestion and utilization by the horse. It is not palatable when used as a grain on its own, however, it can be used in grain mixes. Like corn, sorghum is high in digestible energy and low in fiber.

Barley also has hard hulls that should be processed to allow easier digestibility. It has moderate fiber and energy content, and can be a nutritious and palatable feed for horses.

Wheat is generally not used as a feedstuff because of its high cost. Its small hard kernels should be processed for horses to digest. Wheat is higher in energy than corn and best used in a grain mix because of its low palatability.

Protein Supplements

Soybean meal is the most common protein supplement, which averages around 44% crude protein. The protein in soybean meal is usually a high-quality protein with the proper ratio of dietary essential amino acids.

Cottonseed meal (48% crude protein) and peanut meal (53% crude protein) are not as common for horses as soybean meal.

Brewer’s grains (the mash removed from the malt when making beer) are a byproduct of the brewing industry. It is nutritious and palatable with about 25% crude protein and is also high in fat (13%) and B vitamins.


Fat Supplements

Vegetable oil is the most commonly used fat source in horse feeds. If adding the oil supplement as a top dress to feed start with ¼ cup/feeding and increase to no more than 2 cups/day over the course of 2 weeks for the average size horse (1000 lbs.).

Rice bran is a newer fat supplement on the market. It is distributed by some commercial feed dealers. It consists of about 20% crude fat, giving it an energy content of 2.9 Mcal/kg.

Forage is the base! Always try to feed the most forage possible then add concentrate.

Feed at a rate of 1.5 to 2% of the horse’s body weight (1000 lb. horse = 20 lbs.).

Feed by weight not volume!
** A 1 lb. scoop of Oats does not equal 1 lb. of Corn**

Stomachs are small so concentrates, if used, should be fed twice a day if not more with no more than 0.5% body weight per feeding.

To maintain body weight, most horses need only good forage, water, and a mineral block.

Store feed properly: it should be kept free of mold, rodents, or contamination.

Keep Ca:P ratios around 2 parts Ca to 1 part P.

Feed on a set schedule (horses are creatures of habit and are easily upset by changes in routine).

Change feeds gradually (horses’ stomachs cannot cope with drastic changes in feed could cause colic).

When work or exercise decreases, decrease the grain.

Be aware of the pecking order in your horse’s pen— are they getting their feed?

Examine teeth at least once a year to make sure they are able to chew feed.

References and Supplemental Reading

Lewis, L.D. 1995. Feeding and Care of the Horse (2 nd edition). Williams & Wilkins, Philadelphia, PA.

National Research Council. 1989. Nutrient Require­ments of Horses. National Academy Press, Washington, DC.


Joint Data Analysis in Nutritional Epidemiology: Identification of Observational Studies and Minimal Requirements

Background: Joint data analysis from multiple nutrition studies may improve the ability to answer complex questions regarding the role of nutritional status and diet in health and disease.

Objective: The objective was to identify nutritional observational studies from partners participating in the European Nutritional Phenotype Assessment and Data Sharing Initiative (ENPADASI) Consortium, as well as minimal requirements for joint data analysis.

Methods: A predefined template containing information on study design, exposure measurements (dietary intake, alcohol and tobacco consumption, physical activity, sedentary behavior, anthropometric measures, and sociodemographic and health status), main health-related outcomes, and laboratory measurements (traditional and omics biomarkers) was developed and circulated to those European research groups participating in the ENPADASI under the strategic research area of "diet-related chronic diseases." Information about raw data disposition and metadata sharing was requested. A set of minimal requirements was abstracted from the gathered information.

Results: Studies (12 cohort, 12 cross-sectional, and 2 case-control) were identified. Two studies recruited children only and the rest recruited adults. All studies included dietary intake data. Twenty studies collected blood samples. Data on traditional biomarkers were available for 20 studies, of which 17 measured lipoproteins, glucose, and insulin and 13 measured inflammatory biomarkers. Metabolomics, proteomics, and genomics or transcriptomics data were available in 5, 3, and 12 studies, respectively. Although the study authors were willing to share metadata, most refused, were hesitant, or had legal or ethical issues related to sharing raw data. Forty-one descriptors of minimal requirements for the study data were identified to facilitate data integration.

Conclusions: Combining study data sets will enable sufficiently powered, refined investigations to increase the knowledge and understanding of the relation between food, nutrition, and human health. Furthermore, the minimal requirements for study data may encourage more efficient secondary usage of existing data and provide sufficient information for researchers to draft future multicenter research proposals in nutrition.


PSYCHOSOCIAL HEALTH

Research supports the positive impact of physical activity on the overall psychological health and social engagement of every student. A well-designed physical education curriculum provides students with social and emotional benefits (NASPE, 2001). Simultaneously, exposure to failure experiences, emphasis on competitive sports, and elitism for naturally inclined athletes, along with bullying and teasing of unfit, uncoordinated, and overweight youth, may be important factors discouraging participation in current and future physical activity (Kohl and Hobbs, 1998 Sallis et al., 2000 Allender et al., 2006). School-based physical activity, including physical education and sports, is designed to increase physical activity while also improving motor skills and development, self-efficacy, and general feelings of competency and engaging children socially (Bailey, 2006). The hoped-for psychosocial outcomes of physical education and other physical activity programs in the school setting have been found to be critical for continued physical activity across the life span and are themselves powerful long-term determinants of physical activity (Bauman et al., 2012). Unfortunately, significant gaps exist between the intent and reality of school-based physical education and other activity programs (HHS, 2013).

A large number of psychological and social outcomes have been examined. Specific aspects of psychosocial health showing a beneficial relationship to physical activity include, among others, self-efficacy, self-concept, self-worth (Haugen et al., 2011), social behaviors (Cradock et al., 2009), pro-school attitudes, motivation and goal orientation (Digelidis et al., 2003), relatedness, friendships (de la Haye et al., 2011 Macdonald-Wallis et al., 2011), task orientation, team building, bullying, and racial prejudice (Byrd and Ross, 1991). Most studies are descriptive, finding bidirectional associations between psychosocial outcomes and physical activity. Reviews and meta-analyses confirm a positive association between physical activity and self-esteem, especially for aerobic activities (McAuley, 1994).

Among psychosocial factors, self-efficacy (confidence in one's ability to be physically active in specific situations) has emerged as an important correlate of physical activity from a large body of work based on the durable and practically useful social learning theory (Bandura and McClelland, 1977 Bandura, 1995). Bandura's theory compels consideration of the psychosocial and physical environments, the individual, and in this case the behavior of physical activity. Using this framework, physical activity itself has been shown to be a consistent positive correlate as well as a determinant of physical activity in children and adolescents. A large amount of reviewed research has found that physical education and physical activity experiences can increase children's confidence in being active and lead to continued participation in physical activity (Bauman et al., 2012). RCTs have shown that both self-efficacy and social interactions leading to perceived social support influence changes in physical activity (Dishman et al., 2009). Skill mastery, confidence building, and group support are well-known strategies for advancing student learning and well-being in many educational domains in the school setting and apply equally to school physical education and other physical activity. Early observational studies of physical, social, and environmental determinants of physical activity at home, school, and recess indicated that prompts to be active (or not) from peers and adults accounted for a significant amount of the variance in directly observed physical activity (Elder et al., 1998). One longitudinal study following the variability and tracking of physical activity in young children showed that most of the variability in both home and recess activity was accounted for by short-term social and physical environmental factors, such as prompts from others and being outdoors (Sallis et al., 1995). Another study, examining activity among preschool children, found that, contrary to common belief, most of the time spent in preschool was sedentary, and correlates of activity were different for preschool boys and girls (Byun et al., 2011). In addition, significant variation in activity by preschool site was noted, indicating that local environmental conditions, including physical environment and equipment, policies, and teacher and administrative quality characteristics, play an important role in promoting physical activity (Brown et al., 2009).

Studies in middle and high school populations have strengthened the evidence base on relationships among self-efficacy, physical activity, and social support (from adults and peers). This research has highlighted the central contribution of self-efficacy and social support in protecting against a decline in activity levels among adolescent girls (Dishman et al., 2009, 2010). Evidence indicates further that these impacts spread to activities outside the school setting (Lytle et al., 2009). Findings of a related study suggest that leisure-time physical activity among middle school students was linked to motivation-related experiences in physical education (Cox et al., 2008).

A recent review of reviews (Bauman et al., 2012) found that population levels of physical activity are low and that consistent individual-level correlates of physical activity are age, sex, health status, self-efficacy, and previous physical activity. Physical activity declines dramatically as children progress from elementary through high school (Nader et al., 2008). Boys are consistently found to be more active than girls from ages 4 to 9. For other age groups of children and adolescents, sex is correlated with but not a determinant of activity (Bauman et al., 2012). These findings suggest the need to tailor physical education and physical activity programs for youth specifically to increase self-efficacy and enjoyment of physical activity among girls (Dishman et al., 2005 Barr-Anderson et al., 2008 Butt et al., 2011).

In summary, a broad range of beneficial psychosocial health outcomes have been associated with physical activity. The promotion of more physical activity and quality physical education in the school setting is likely to result in psychosocially healthier children who are more likely to engage in physical activity as adults. Schools can play an important role in ensuring opportunities for physical activity for a segment of the youth population that otherwise may not have the resources to engage in such activity. It makes sense to assume that, if physical activity experiences and environments were once again structured into the daily school environment of children and adolescents, individuals' feelings of self-efficacy regarding physical activity would increase in the U.S. population.


4. Current Challenges and Remaining Knowledge Gaps to Continue Expanding Exercise’s Molecular Landscape

4.1. Metabolite Identification and Annotation

To continue expanding the exercise molecular landscape in the next decade, metabolite and lipid identification/annotation still represents a main challenge and bottleneck of untargeted metabolomics and lipidomics approaches, in contrast to protein identification in proteomics, for example. Whereas proteins are composed of a finite and more manageable combination of different amino acids that can be sequenced by matching experimental peptides against in silico fragmentation spectra, metabolites (including lipid species) are a highly heterogenous group of small molecules resulting from countless different chemical structures and atomic combinations, although predominantly composed of the elements C, H, N, O, P and S [137]. Despite recent technological advances in analytical instrumentation that have enabled rapid and simultaneous detection of thousands of metabolites from very low volumes of biological samples, a much smaller portion of these metabolites can remain after stringent data processing and cleaning processes prior to any attempt at identification/annotation [138]. These data processing and cleaning steps are essential to generate more high-confidence metabolomic and lipidomic datasets, but the overall trade-off is reduced metabolite coverage.

Next, metabolites and lipid features (such as mass-to-charge ratios and retention times) that meet quality control criteria can still correspond to numerous molecular structures. Their identification𠅊 term used when the highest level of confidence is reached level 1—or annotation (lower level of confidence in metabolite characterization, levels 2 to 3) [51] notably depends on an existing reference match in currently available databases, and preferably an in-house generated database. This is important, as the vast majority of features currently fail to match any metabolite from these databases and are therefore assigned as “unknowns”. These unknowns may be true unknowns (i.e., compounds for which no chemical structure, name, origin, and biological function has been described to date), but some compounds may however be assigned as unknowns because the reference is missing from the available databases. Most existing databases are still largely incomplete, and in the case of true unknown metabolites and/or lipids, extensive efforts in analytical chemistry are required to characterize their molecular structure. However, these characterization efforts are rarely undertaken given their challenging and time-consuming nature [139]. As a result, unknowns within datasets are often disregarded, and attention is instead focused on only putatively named metabolites. In the case of compounds that are matched against a database, additional information is necessary to accurately identify and validate a single candidate since basic features such as retention time and m/z may have multiple candidates. MS 2 (and sometimes MS n ) is required to reach the highest level of confidence, as fragmentation patterns help elucidate molecular structures and distinguish metabolites with similar m/z and retention times by matching them with fragmentation patterns of authentic chemical standards within metabolite libraries. Nevertheless, most libraries are still largely incomplete, therefore the number of authentic chemical standards available represents a current limiting factor to metabolite identification of the broader metabolome. Additionally, compounds can exhibit different levels of confidence in identification/annotation, making data integration and interpretation even more challenging since most commonly used dedicated tools (e.g., KEGG, MetaboAnalyst 3.0) require metabolite identification (i.e., level 1) to integrate the data into biological context [137].

Efforts to expand libraries with authentic standards in the next decade will help exploit the full potential of untargeted metabolomics by yielding a much higher coverage of unequivocally identified metabolites. MS 2 is however more time- and resource-consuming. In addition, validation of metabolite identification/annotation still requires extensive human intervention, since this step is usually performed manually and requires expertise in chemical structure and biochemistry. This hurdle may become a growing issue as the number of metabolites to manually validate increases with the expansion of metabolite libraries in the years to come. It is also important to note that MS 2 is not always sufficient to distinguish structural isomers𠅌ompounds with identical molecular formula but different chemical bond arrangements between atoms𠅊nd stereoisomers𠅌ompounds with identical formula and chemical bond arrangements but different spatial orientation of groups in the molecule [37,140,141]. In this case, additional separation methods (i.e., TIMS) in conjunction with MS n may be required to validate the identification of a metabolite or lipid species. Of note, NMR represents a quicker and cheaper alternative (in terms of cost per sample) to MS n with regard to structural elucidation [142].

4.2. Human Interindividual Variability and Potential Confounding Factors

One of the main challenges encountered in human exercise studies is the high interindividual variability in genetic background, sex, age, lifestyle, environmental exposure and nutritional and health status ( Figure 4 ), which represent important confounding factors that are difficult to screen and control for in an experimental setting [10]. To overcome these challenges and account for the potential high interindividual variability amongst human participants, large-scale epidemiological studies are required [143]. Recruiting and analyzing such large numbers of individuals for a given experiment will be challenging (i.e., the appropriate sample size is variable depending on effect size, but hundreds of participants are often needed in human studies), as human exercise studies are usually performed using only small sample sizes (i.e., often less than one hundred). It should also be noted that overcoming high interindividual variability may be possible in small study groups through meticulous control of the above-mentioned confounding factors although this may lead to increased cost, time and constraints. Parallel exercise interventions using animal model systems is a complementary approach in which both genetic background and environment can be controlled to a greater extent compared to human cohorts.

Summary of some of the main factors responsible for variance between metabolomics/lipidomics studies, including intrinsic, extrinsic/environmental factors and experimental factors.

Human metabolomics studies to investigate the molecular mechanisms of acute exercise are however starting to be performed at a larger scale. Indeed, a recent study investigated blood metabolic profiles of over 400 middle-aged adults, uncovering metabolic signatures associated with cardiometabolic health [144]. In addition, an ongoing initiative in the United States called The Molecular Transducers of Physical Activity Consortium (MoTrPAC) will address some of these remaining challenges in the decade ahead by examining the effects of acute and chronic exercise (including both endurance and resistance exercise) across a wide range of biological systems. This multi-site MoTrPAC initiative aims to analyze a large number of samples across pediatric, sedentary and highly active adult male and female human populations and complementary animal models using multi-omic approaches (including metabolomics/lipidomics), eventually establishing a comprehensive molecular map of exercise that will be made publicly available through the MoTrPAC Data Hub: https://motrpac-data.org (accessed on 15 December 2020) [145,146].

Metabolomics/lipidomics studies in the fields of sport and exercise physiology to date have mostly been conducted using only male participants, as highlighted in a recent human exercise metabolomics review [147], with only a few recent studies investigating acute exercise metabolomic/lipidomic patterns in obese and insulin resistant women [80,148,149]. The impacts of sex and hormonal variations (i.e., menstrual cycle phases) in females on exercise-induced metabolomic and lipidomic responses are therefore poorly understood, and more studies in female participants are warranted to begin to decipher these differences. These studies should take into account and report the use of hormonal contraception (including type of hormonal contraception used) in addition to the menstrual cycle phase during which the exercise is performed. This reporting is important as substantial differences in metabolic patterns are observed depending on menstrual cycle phase [150]. Likewise, aging is also associated with alterations in exercise-induced metabolomic responses. Therefore, continued efforts to identify new exercise-regulated biomarkers associated with aging and age-related pathologies such as muscle loss in sarcopenia may help personalize exercise interventions to prevent, delay or treat these age-related disorders [9]. As highlighted in previous sections, sampling certain tissues such as liver, which are relatively inaccessible in human exercise studies, can be more readily obtained using animal model systems. Since exercise-induced adaptations do not just involve changes in circulating, muscle and liver metabolites/lipids, animal models also provide more access to less-studied tissues (e.g., heart, brain) involved in the whole-body molecular metabolic responses to exercise.

4.3. Comparison and Reproducibility of Results Between Studies

Another major challenge in exercise-related metabolomics and lipidomics studies is the ability to directly compare studies between independent studies and research groups. The current lack of reproducibility and the common discrepancies observed within a given research field may in part be attributed to intrinsic and extrinsic/environmental confounding factors described in the previous section, as well as experimental factors (see Figure 4 ). Study designs should report or control for these factors (e.g., reporting dietary intake and timing and/or providing standardized meals at set times). Included in these experimental factors is the use of a wide variety of analytical platforms and data acquisition modes. Indeed, each analytical platform and detection mode is associated with specific sample handling, metabolite extraction and data acquisition/processing protocols and requirements. Although representing a valuable means to broaden metabolite coverage, these differences in instrumentation and analytical workflows contribute to substantial inter-study discrepancies that make reproducibility and data comparison between independent research groups a challenging and tedious process. Despite the fact that instrumentation-induced variability between studies cannot likely be solved due to differences in equipment between research facilities, harmonization in sample handling and data acquisition/processing protocols, along with standardized metabolite reporting are necessary to help overcome some inter-study discrepancies. This will allow more confident inter-study dataset comparisons, and subsequently improved data interpretation and biological insights. In 2007, the MSI proposed a consensus regarding minimum reporting standards for metabolite identification [51]. Similarly, the LSI also provides guidelines for lipid species annotation [151,152]. However, efforts to enforce adequate use and constant updates by the metabolomics community are necessary since, up until recently, the use of these reporting standards allowing investigators to define the level of compound identification/annotation confidence was suggested to be relatively low [141].

4.4. Bioinformatic Resources

To deal with the complexity and heterogeneity of metabolomics and lipidomics datasets (e.g., wide concentration range suggested to be spread over 12 orders of magnitude [139]) and the large amount of data generated by untargeted approaches, robust computational and bioinformatics resources and expertise are required. This is critical for data processing, analysis, interpretation and visualization. Numerous open-source and commercial data processing tools are available, but the overall lack of uniformity among these tools can also hinder reproducibility of findings between independent studies and research groups. Each tool has its own characteristics, but comparison of the performances of different tools has rarely been performed. Although software packages such as XCMS Online, SIEVE™ and Compound Discoverer™ provide reproducible and consistent data processing results, they have shown differences in metabolite selection, for example as candidate biomarkers for Alzheimer’s Disease [153]. Therefore, variations in data analysis among these different software packages should be carefully considered, and ideally systematic comparison of all packages utilized in untargeted metabolomics/lipidomics should be performed to help maximize data confidence, consistency in data handling, and reliability and reproducibility of biological findings. Alternatively, utilizing multiple software packages for data handling and only considering overlapping compounds for subsequent analysis may help reduce false positive and false negative compounds in datasets [153]. In addition, data analysis code should be provided as open access, as lack of transparency and reporting standards has led to widespread concerns in the reproducibility and integrity of results. Metabolomics researchers are encouraged to share their resources to provide adequate evidence of reproducibility. Collaborative cloud computing and Jupyter Notebooks are becoming popular amongst many metabolomics research groups and seem to be favored, as they provide added flexibility when compared to many of the online data repositories [154]. Metabolomics users are encouraged to use open-source platforms and adopt the FAIR data principles (Findable, Accessible, Interoperable, and Reusable) [155], promoting the use of open data formats, online spectral libraries and data reproducibility.


6.7: Exercise 2 - Identifying strains by nutritional requirements - Biology

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Nutritionally recommended food for semi- to strict vegetarian diets based on large-scale nutrient composition data

Diet design for vegetarian health is challenging due to the limited food repertoire of vegetarians. This challenge can be partially overcome by quantitative, data-driven approaches that utilise massive nutritional information collected for many different foods. Based on large-scale data of foods' nutrient compositions, the recent concept of nutritional fitness helps quantify a nutrient balance within each food with regard to satisfying daily nutritional requirements. Nutritional fitness offers prioritisation of recommended foods using the foods' occurrence in nutritionally adequate food combinations. Here, we systematically identify nutritionally recommendable foods for semi- to strict vegetarian diets through the computation of nutritional fitness. Along with commonly recommendable foods across different diets, our analysis reveals favourable foods specific to each diet, such as immature lima beans for a vegan diet as an amino acid and choline source, and mushrooms for ovo-lacto vegetarian and vegan diets as a vitamin D source. Furthermore, we find that selenium and other essential micronutrients can be subject to deficiency in plant-based diets, and suggest nutritionally-desirable dietary patterns. We extend our analysis to two hypothetical scenarios of highly personalised, plant-based methionine-restricted diets. Our nutrient-profiling approach may provide a useful guide for designing different types of personalised vegetarian diets.

Conflict of interest statement

The authors declare no competing interests.

Figures

Nutritional fitness (NF) and underlying…

Nutritional fitness (NF) and underlying nutrients across diets. We here consider four different…

Highly personalised, mainly plant-based diets.…

Highly personalised, mainly plant-based diets. We here consider the following two personalised cases:…


Culture Media: Types, Preparation and Requirements

The culture media (nutrients) consist of chemicals which support the growth of culture or microorganisms. Microbes can use the nutrients of culture media as their food is necessary for cultivating them in vitro.

Types of Culture Media:

The first medium prepared was meat-infusion broth. As most pathogenic microbes require complex food similar in composition to the fluids of the animal body, it was Robert Koch and his colleagues who used meat infusion and meat extracts as basic ingredients in their culture media for the isolation of pathogenic microbes, while one of his assistant named Petri designed and developed glass dishes, known today as Petri dishes, are used in microbiological work.

On the basis of chemical composition, the culture media are classified into two types:

(i) Synthetic or chemically defined medium:

These media are prepared by mixing all the pure chemicals of known composition for e.g. Czapek Dox medium.

(ii) Semi-synthetic or undefined medium:

Such are those media, where exact chemical composition is unknown e.g. potato dextrose agar or MacConkey agar medium.

On the basis of consistency, the culture media are of three types:

(a) Solid medium or synthetic medium:

When 5-7% agar agar or 10-20% gelatin is added the liquid broth becomes solidified. Such media are used for making agar slants or slopes and agar stab.

(b) Liquid medium or broth:

In such cases no agar is added or used while preparing the medium. After inoculation and later incubation, the growth of cells becomes visible in the form of small mass on the top of the broth.

(c) Semi-solid or floppy agar medium:

Such media are prepared by adding half quantity of agar (1/2 than required for solid medium) i.e. about 0.5% in the medium. This type of medium may be selective which promote the growth of one organism and retards the growth of the other organism. On the other hand, there are differential media which serve to differentiate organisms growing together.

Preparation of Medium:

The liquid medium or broth is prepared by dissolving the known amounts of chemicals in distilled water the pH is adjusted by adding N/10 HCl or 1N NaOH. The liquid medium is dissolved into either Erlenmeyer flasks or rimless clean test tubes.

In 15 ml capacity of test tube, 5 ml medium should be poured while in flask of 250 ml capacity, the amount of the medium should be 100 ml. These are then plugged with non-adsorbent cotton plugs. The plugged tubes or flasks should be wrapped by brown paper and placed for sterilization by autoclaving at a pressure of 15 lbs/inch 2 (at temperature 121°C), for 15 min.

The heat sensitive substances (protein or enzymes etc.) should be sterilized by using membrane filters (millipore). The agar agar is to be dissolved separately and dispensed after dissolving all ingredients of the medium. It is first to be noted that all the glassware in use should be sterilized in oven at 170°C for 3 h before using them. Such sterilized glassware is needed for pouring the medium used for culturing the microor­ganisms.

Each and every biological process requires energy for their vital activities. The basic cell building requirements are supplied by the nutrition, which is ma­nipulated according to its requirement. Nutrition not only provides energy but also acts as precursors for growth of microorganisms.

The nutritional require­ment of an organism depends upon the biochemical capacity. If an organism is capable of synthesizing its own food using various inorganic components, requires a simple nutritional diet whereas organism unable to meet such synthesis requires complex organic substances.

Minimal Requirements:

Every microbe has its own specific minimal nutritional requirement. If it is not provided, they do not grow. This minimal requirement consists of a carbon source, nitrogen source, sulphur source, phosphorus source besides energy source.

They grown better in the presence of particular amino acids or vitamins or other compounds, so that the species could grow or develop better. Microbes can utilize a wide range of substrates from complex form of compounds (lignin etc.) that are generally not used by other forms of life.

Carbon source (glucose etc.) is essential for the basic cell structure because each and every biomolecule is made up of carbon along with other compounds. Nitrogen source is required for the biosynthesis of amino acids, nucleic acids, enzymes etc. Sulphur and phosphorous required for synthesizing nucleic acids, vitamins, and certain amino acids.

A photosynthetic microorganism eg. Cyanobacteria do not require a energy source. They use sunlight and trap the form of chemical energy, used frequently. With the help of CO2 and water, they synthesize food in the form of carbohydrate. But many microorganisms need some energy sources. This is met out by organic compounds. Some microbes have special capacity. They can harvest energy from redox potential for their vital activities.

Nutritional Types of Microorganisms:

Based on the way of harvesting energy, they are classified into two major groups. Those organisms that can make use of external energy sources and assimilate inorganic carbon are called as autotrophs.

Blue green algae and some chemosynthetic bacteria belong to this group.

They can make use of sunlight/ redox potential as their energy source. CO2 is the main and sole carbon source. Nitrogen is assimilated in the form of NH4 + , sulphur as SO4 – – and phosphorus in PO4 – – from their surroundings.

Further, autotrophs may be of two types:

Photoautotrophs are bacteriochlorophyll containing microorganisms, while chemoautotrophs, utilize various oxidation-reduction reactions as their energy source. During oxidation, energy is released hence the microbes oxidize the reduced traditional compounds and make use of the released electrons i.e. energy in case of sulphur bacteria (Thiobacillus spp.) and nitrifying bacteria (Nitrosomonas spp.). The phototrophs utilize solar energy to oxidizes from O – (singlet) stage to O2 stage and thus utilizes the electrons released (Table 3.3).

Many microorganisms resemble animals and humans, using organic compounds. These are called chemoorganotrophs but when they use inorganic chemicals as energy source, called chemolithotrophs.


Food Labels Learning Sheets and Worksheets

Food labels are an important part of helping kids learn to make healthy choices. Food labels provide basic information about the nutrition inside foods so that children can begin to see how foods are different.

Our learning and activities sheets make learning to read food labels fun for kids. Chef Solus takes the mystery out of the food labels so kids can develop healthy habits at a young age.

Our food label printables has learning sheets, worksheets and even sample food labels!

It is best if the children bring sample food labels from foods they are actually eating at home. This will help generate conversation with their parents about food labels and the importance of reading them.

However, in case you need some extra food labels, we have provided sample food labels for the students to use in class. Each sheet has two food labels.

To find the sample food labels quickly just select Activities for Kids in the "Printable Type" pull down menu below. See all our nutrition education printables for preschool and elementary school children!


Watch the video: Top 50 OG Strains (October 2022).