Dietary ascorbic acid,pyridoxine and riboflavin reduce the light sensitivity of larvae and pupae of Drosophila melanogaster

Drosophilia melanogaster is light sensitive. On low yeast media, light induces high mortality during the development from egg to adulthood and increases development time. This effect of light is strongly dependent on the yeast-concentration. Addition of 8 vitamins, normally present in yeast, protects Drosophila against light under laboratory conditions. In this study we have analyzed the significance of the individual vitamins for both survival and development at high light intensities. Two D. melanogaster strains were utilized: a control strain C and a strain P. The latter had been adapted to a palmitic acid supplemented medium. In addition, we investigated the effect of vitamin C, a vitamin typically found in fruit, but not in yeast. It appears that both pyridoxine and riboflavin are essential for the survival of the control strain C under high light intensities, and they act synergistically. The other 6 tested vitamins can be omitted in these survival experiments. Moreover survival under high light conditions also improved strongly on media supplemented with vitamin C. The other strain (P), which was for many generations kept on a different food-medium, also was protected on yeast media by riboflavin and pyridoxine, and by vitamin C, although the survival at high light intensities on media with riboflavin and pyridoxine was less than the survival of the control strain.     

EFFECTS OF CERTAIN LIMITING CONDITIONS ON THE SYNTHESIS OF B VITAMINS BY YEAST

In yeast crops which were grown in the presence of various inhibitors, there was considerable variation in content of the various B vitamins. A higher degree of parallelism in variation in content was found to exist between thiamine and niacin than between any other pair of vitamins; this has been interpreted as indicating that the predominant functions of these two vitamins are their established rôles in fermentation. Values for inositol indicate that it may be involved in fermentation processes, but this is not the case for other members of the B complex. Biotin appears to be unique since in no case did the biotin content of yeast grown in the presence of an inhibitor fall below that of the control yeast. There was some evidence of synthesis of biotin, or a material with biotin activity, in the presence of certain inhibitors, the most striking instance being with sulfaguanidine. An exogenous supply of biotin was essential for extensive proliferation of F. B. yeast, and yeast grown in a medium to which biotin was the only added vitamin contained the B vitamins in amounts very similar to those found in the control yeast, the most marked differences being in increased vitamin B₆ and p-aminobenzoic acid contents. In the absence of biotin, significant amounts of all of the B vitamins except biotin were synthesized, both in the presence and absence of certain other members of the B complex. The addition of thiamine, pyridoxine, inositol, and β-alanine to the culture medium caused a reduction in the amounts of vitamin B₆ and p-aminobenzoic acid synthesized. F. B. yeast was able to grow in a xylose medium only when certain of the B vitamins were present, and even then growth was limited. Evidence was obtained for some synthesis of all of the vitamins investigated except biotin and vitamin B₆. The most significant differences in vitamin content between galac yeast and the parent F. B. strain were in folic acid and vitamin B₆, the former being considerably reduced in amount, the latter being increased.     

Variety of effects of vitamins on yeast cells in aerobic conditions]

The effect of thiamine and biotin on the processes of cell division, assimilation of glucose, and accumulation of the biomass and nitrogen in the cells was studied with the Candida yeast. The action of the vitamins depended on the source of nitrogen. In some strains, asparagine can substitute for biotin. Biotin has different effect on the production of gamma-aminobutyric acid in Candida pulcherrima, C. guilliermondii. C. tropicalis K3-10. High concentrations of arginine were found in C. guilliermondii var. membranaefaciens in the presence of biotin. The vitamins did not favour the assimilation of nitrate nitrogen in species which were not adapted to this source of nitrogen.     

Prototrophic hybrids of bakers yeast. I. Selection of haploids and diploids of prototrophic yeast

153 haploids, including 8 prototrophs, 12 biotin prototrophs and 4 biotin auxotrophs were isolated from Y, F and FB strains of the baker's yeast Saccharomyces cerevisiae. Remaining haploids were dependent on vitamins of B group other than biotin. Obtained haploids were characterized by large cell sizes, a or α mating type, the ability to fermentation of sugars and the assimilation of non-fermented carbon sources. Haploids obtained from the yeast of Y and FB strains a good growth in the synthetic medium. Prototrophic haploids, prototrophic haploids with biotin auxotrophs and biotin prototrophs with biotin auxotrophs were crossed. 89 prototrophic hybrids capable of growth in synthetic medium without vitamins were selected out of 178 hybrids obtained. Hybrids are characterized by features typical for baker's yeast; however, not all of them are capable of sporulation. As result of selection, prototrophic hybrids and 16 hybrids characterized by a good increase of biomass in molasses medium were chosen. The efficiency of the biomass of hybrids designated as YY 3040/2, YY 3040/3 and FFB 1910/2 is considerably higher than one obtained from the cultivation of the industrial strain French Mautner (Mf). All hybrids possess adequate enzymatic activity in anaerobic metabolism of saccharose and maltose. Selected prototrophic hybrids were sent out to two yeast factories in the country for experimental propagation.     

Effect of Biotin on Fatty Acids and Phospholipids of Biotin-Sensitive Strains of Rhizobium japonicum

The effect of biotin on fatty acids and intact lipids was studied by comparing a biotin-requiring, a biotin-inhibited, and a biotin-indifferent strain of Rhizobium japonicum. These organisms were grown in a defined medium with added levels of 0, 0.3, and 0.5 μg of biotin per liter, and were analyzed for fatty acids and lipid components. Myristic, palmitic, and octadecenoic acids were found to be the major fatty acids in these strains. The indifferent strain also contained large amounts of C₁₉ cyclopropane acid and small amounts of a C₁₇ cyclopropane acid. Several unidentified acids were present in the other two strains. The percentages of fatty acids showed statistically significant changes corresponding with changes in level of biotin in the medium. When biotin concentration was increased in the medium, the C₁₈ monoenoic acids of the biotin-requiring strain increased significantly, and those of the biotin-inhibited and biotin-indifferent strains decreased significantly. Palmitic acid showed a statistically significant increase in the indifferent strain with increasing biotin concentration. The principal intact lipid components in these strains are phospholipids. The major phospholipids are phosphatidylserine, phosphatidylcholine, phosphatitidylethanolamine, and cardiolipin. These phospholipids were not affected by biotin level and were independent of medium composition.     

Effect of the chemical nature of the carbon source in the medium on the makeup of the biomass]

The yeast Candida tropicalis, Candida utilis, Trichosporon cutaneum were cultivated on the synthetic medium containing additions of group B vitamins (biotin, thiamin) and glucose, glycerol of lactic acid as the sole source. The protein content, amino acid composition, nucleic acids and complex B vitamins were identified in the resultant biomass. The carbon source in the medium affected these indices. The protein and nucleic acid content also depended on the yeast strain.     

Evaluation of dietary essentiality of vitamins for Penaeus monodon (Fabricius)

The effect of exclusion of individual water-soluble (thiamine, riboflavin, pyridoxine, cyanocobalamin, pantothenic acid, folic acid, niacin, biotin, choline, inositol, ascorbic acid) and fat-soluble vitamins (vit. A, D, K and E) in semi-purified diets on growth and survival of juvenile shrimp, P. monodon was studied in the laboratory for 8 weeks. Diets lacking riboflavin and vitamin K did not affect growth and survival of shrimp. However, deletion of inositol and choline resulted in poor growth. Maximum growth was observed in the control diet (C1) which was supplemented with all vitamins. Diet deficient in ascorbic acid, biotin, folic acid, niacin, thiamine and alpha-tocopherol resulted in poor appetite and poorer feed conversion efficiency. All treatments except the control (C1) resulted in histological changes in the digestive gland cells. Detachment or destruction of the epithelial cells was observed in all treatments lacking individual vitamins but more severely in the treatment without a vitamin supplement followed by inositol, choline and ascorbic acid deficient diets.     

The effect of larval age range on survival of twoTribolium castaneum strains in mixed cultures,through pupal cannibalism

The effect of larval age range on survival of two Tribolium castaneum strains in mixed cultures was studied in an experimental situation in which other selective forces were reduced to a minimum. Increasing the difference in larval age setween the strains by one day resulted in a reduction of survival of the faster-developing mutant strain, because more of its earlier pupae were cannibalized by the larvae. General aspects of the effects of pupal cannibalism by larvae on the outcome of intra-specific competition (sensu lato) in Tribolium are discussed.     

草地贪夜蛾高致病力绿僵菌菌株的筛选与鉴定

为获取对草地贪夜蛾Spodoptera frugiperda具有高致病力的生防真菌,从福建省不同地区分离得到8株寄主为鳞翅目和半翅目幼虫僵虫的绿僵菌Metarhizium,采用浸渍法测定了其对草地贪夜蛾2龄幼虫和蛹的致病力,并根据形态学和分子生物学方法对高致病力菌株进行种类鉴定。结果表明,8株绿僵菌菌株对草地贪夜蛾2龄幼虫和蛹均表现出不同程度的致病力,其中菌株FJMR2和FJXY7表现出较强的致病力。在5×107个/mL孢子浓度下,FJMR2和FJXY7对草地贪夜蛾2龄幼虫的致死率分别为88.76%和82.13%,对蛹的致死率分别为86.57%和84.00%;对草地贪夜蛾2龄幼虫的LT50分别为4.81 d和4.93 d,对蛹的LT50分别为4.94 d和4.83 d。经鉴定菌株FJMR2和FJXY7均为莱氏绿僵菌Metarhizium rileyi。本研究获得2株对草地贪夜蛾2龄幼虫和蛹具有高致病力的莱氏绿僵菌菌株,在草地贪夜蛾的生物防治中具有较大应用潜力。     

Effects of B group vitamins and choline chloride on the development and protein synthesis in the male larvae of Pimpla turionellae L. (Hym., Ichneumonidae)

The effects on the development and protein levels in the larvae of male Pimpla turionellae L. of different amounts of B group vitamins namely thiamin, riboflavin, Ca-pantothenate, nicotinic acid, pyridoxine-HCl, folic acid and biotin and a growth factor choline chloride in the meridic diet were investigated. Among the vitamins tested, choline chloride and biotin were found to have quantitatively critical values in the diet and increased amounts of nicotinic acid and folic acid individually in the control diet showed positive effects on development and protein levels. A decrease in the levels of Ca-pantothenate and pridoxine-HCl caused decreases in protein levels, whereas variations in the levels of thamin and riboflavin did not have any significant effect.     

Engineering of biotin-prototrophy in Pichia pastoris for robust production processes

Biotin plays an essential role as cofactor for biotin-dependent carboxylases involved in essential metabolic pathways. The cultivation of Pichia pastoris, a methylotrophic yeast that is successfully used as host for the production of recombinant proteins, requires addition of high dosage of biotin. As biotin is the only non-salt media component used during P. pastoris fermentation (apart from the carbon source), nonconformities during protein production processes are usually attributed to poor quality of the added biotin.In order to avoid dismissed production runs due to biotin quality issues, we engineered the biotin-requiring yeast P. pastoris to become a biotin-prototrophic yeast. Integration of four genes involved in the biotin biosynthesis from brewing yeast into the P. pastoris genome rendered P. pastoris biotin-prototrophic. The engineered strain has successfully been used as production host for both intracellular and secreted heterologous proteins in fed-batch processes, employing mineral media without vitamins. Another field of application for these truly prototrophic hosts is the production of biochemicals and small metabolites, where defined mineral media leads to easier purification procedures.     

Increased inactivation of Saccharomyces cerevisiae by protraction of UV irradiation.

The principle of equi-effectivity of the product of intensity and exposure time (principle of Bunsen-Roscoe) of UV irradiation has been assumed to be valid for the inactivation of microorganisms in general. Earlier studies claimed higher survival of Escherichia coli B/r with fractionated irradiation compared with single-exposure survival. However, data on the inactivation effect of protraction of UV irradiation are not available. By means of a specially designed UV irradiation apparatus which secured absolute UV dose measurements throughout the experiments, the effects of variation of UV irradiation intensities (253.7 nm) and exposure times were tested on the inactivation of a bacterial virus (Staphylococcus aureus phage A994), a vegetative bacterial strain (E. coli ATCC 25922), and bacterial spores (Bacillus subtilis ATCC 6633) as well as three haploid laboratory strains (RC43a, YNN281, and YNN282) and two diploid strains (commercial bakery yeast strain and laboratory strain YNN281 x YNN282) or yeast (Saccharomyces cerevisiae) and spores of the latter diploid yeast strain. Each test organism was exposed to three UV intensities (0.02, 0.2, and 2 W/m2), with corresponding exposure times resulting in three dose levels for each intensity. Differences in inactivation rates were tested by analyses of variance and Newman-Keuls tests. Virus and bacteria showed no differences in inactivation rates by variation of intensities and exposure times within selected UV doses; hence, the principle of Bunsen-Roscoe could not be rejected for these strains. However, in the eukaryotic test strains of S. cerevisiae longer exposure times with lower intensities led to enhanced inactivation in both haploid and diploid strains, with a more pronounced effect in the diploid yeast strains, whereas in yeast spores in this dose rate effect could not be observed.     

Production of B--vitamins by heterotrophic planktonic bacteria isolated from littoral zone of lake Jeziorak.

Different genera and groups of heterotrophic planktonic bacteria of the littoral zone of the lake Jeziorak produced different B-group vitamins. Most numerous among the planktonic bacteria of this zone of the lake were biotin producers and least numerous were organisms synthesizing riboflavin and nicotinic acid. Most bacteria produced one or two vitamins. Three or more vitamins were produced by only a few strains. In autumn no strain produced all five vitamins studied in this work.     

The Cultivation of Symbiote-free Marine Ciliates in Axenic Medium

SYNOPSIS. Media have been developed for axenic cultivation of 10 strains belonging to 7 species of small marine ciliates. A medium containing cerophyl extract, proteose peptone, trypticase, yeast nucleic acid, biotin, calcium pantothenate folic acid, nicotinamide, pyridoxal HCl, riboflavin, thiamine HCl, and DL-thioctic acid in sea water supports the growth of Uronema nigricans strains Pc and 34/2, Parauronema virginiatum strains 2/1 and 19/1, Miamiensis avidus strains Ma and 19/3, Miamiensis sp. strain 1/1, a strain of "G" ciliate, and strains 33/8 and 34/7 of 2 unidentified species. By substituting a mixture of asolecithin, cephalin, and Tween 80 for cerophyl in the medium, luxurious growth of all except the strains of the 2 unidentified species can be obtained. A defined medium consisting of 18 amino acids, 5 purine derivatives, 8 vitamins, asolecithin, cephalin, and Tween 80 in synthetic sea water also has been developed for 6 of the strains: M. avidus Ma and 19/3, Miamiensis sp. 1/1, P. virginiatum 2/1 and 19/1, and U. nigricans Pc. In general the ciliates grow best at pH 7.2 in the dark at 27 C in media containing sea water of density = 1.015. Under these conditions maximum populations are reached in 4–5 days and range from several hundred thousand to 3 or 4 × 10⁶ depending upon the strain. Electronmicroscopic observations for the presence of endosymbiotes gave negative results.     

Vitamin requirements of larvae of Sitophilus oryzae

Improvements were made in the meridic larval diet for Sitophilus oryzae by replacing the minerals and vitamins supplied by dietary brewer's yeast and wheat germ with mineral and vitamin mixtures. The effects of different concentrations of individual vitamins were studied with the improved diet containing 20% casein. In later tests the dietary casein was replaced with a mixture of 15 amino acids. The results indicated that these larvae, which contain an associated bacteria-like micro-organism, required thiamine, nicotinic acid, pyridoxine, folic acid, and biotin in the diet. No requirement for riboflavin or pantothenic acid could be demonstrated on either the 20% casein diet or the amino acid diet possibly due to contamination of the cornstarch with these two vitamins. In addition, the larvae did not require choline or inositol for the growth of one larval generation.The asymbiotic larvae of S. granarius failed to develop on the improved casein diet indirectly implicating the symbiotes in a nutritional rôle; however, the symbiotes present in S. oryzae apparently do not provide B vitamins. Larvae of S. oryzae failed to develop when the concentration of casein was reduced to 10% while growth was maintained with a 10% concentration of the amino acid mixture. Casein is not an optimal source of amino acids for this species.     

Hsp70 and larval thermotolerance in Drosophila melanogaster: how much is enough and when is more too much?

Heat shock proteins (Hsps) and other molecular chaperones perform diverse cellular roles (e.g., inducible thermotolerance) whose functional consequences are concentration dependent. We manipulated Hsp70 concentration quantitatively in intact larvae of Drosophila melanogaster to examine its effect on survival, developmental time and tissue damage after heat shock. Larvae of an extra-copy strain, which has 22 hsp70 copies, produced Hsp70 more rapidly and to higher concentrations than larvae of a control strain, which has the wild-type 10 copies of the gene. Increasing the magnitude and duration of pretreatment increased Hsp70 concentrations, improved tolerance of more severe stress, and reduced delays in development. Pretreatment, however, did not protect against acute tissue damage. For larvae provided a brief or mild intensity pretreatment, faster expression of Hsp70 in the extra-copy strain improved survival to adult and reduced tissue damage 21h after heat shock. Negative effects on survival ensued in extra-copy larvae pretreated most intensely, but their overexpression of Hsp70 did not increase tissue damage. Because rapid expression to yield a low Hsp70 concentration benefits larvae but overexpression harms them, natural selection may balance benefits and costs of high and low expression levels in natural populations.     

Production of biotin by yeasts

A quantitative screening procedure for biotin and biotin vitamer production was conducted on 129 yeast strains able to grow in a biotin-free medium. Production of biotin and biotin vitamers varied considerably from strain to strain even within a species. The best producers of biotin were strains of Sporobolomyces roseus and Rhodotorula rubra whilst strains of Rhodotorula rubra and Yarrowia lipolytica produced the largest amounts of vitamers.     

Production of B-group vitamins by two Rhizobium strains in chemically defined media

Twenty-eight strains of Rhizobium spp. were tested for their ability to grow in chemically-defined medium lacking growth factors. Two strains, R. meliloti GR4B and Rhizobium spp. ( Acacia ) GRH28, were selected, on the basis of their good growth under the conditions imposed, for further quantification of the production of water-soluble vitamins (thiamine, niacin, riboflavin, pantothenic acid and biotin) in chemically defined media amended with different compounds (mannitol, glucose or sodium succinate) as sole carbon sources. Qualitative and quantitative production of vitamins in chemically-defined media was significantly affected by the use of C sources of a different nature and the age of the cultures. Strain GRH28 produced all the vitamins analysed, and high biological levels of biotin (14 ng ml^–1 culture) were detected after 6 d of culture in mineral medium amended with mannitol. Pantothenic acid was the vitamin detected in the highest amounts (up to 1 μg ml^–1 of culture) in culture supernatant fluids of strain GR4B grown for 6 d with succinate as sole carbon source.     

Nutritional requirements and biochemical activities of pineapple pink disease bacterial strains from Hawaii

Bacteria which cause pink disease of pineapple, identified on the basis of their nutritional and biochemical activities, were found to belong to three genera. These bacteria include the following species: Gluconobacter oxydans, Acetobacter aceti, and Erwinia herbicola. Several pink disease strains required one to three vitamins for growth. Both G. oxydans strains 303D and 180 required biotin, nicotinic acid, and pantothenic acid for growth; E. herbicola 189 required only nicotinic acid; however, A. aceti 295 was able to grow without any added supplements in glucose mineral salts medium. Optimal vitamin concentrations for maximal growth and optimal pH for the maximal number of generations per hour was established for a few pink disease strains.Journal Series Paper No. 2373 of the Hawaii Agricultural Experiment Station, Honolulu.     

Nutrition of Coryneform Bacteria from Milk and Dairy Sources

S ummary . Growth requirements were determined for 112 cultures of coryneform bacteria including strains of Corynebacterium bovis, C. ulcerans and C. lacticum ; in general they were quite distinctive. Of 42 C. bovis strains all had an unsaturated fatty acid requirement fulfilled in chemically defined media by Tween 80, and, but for an atypically nonureolytic strain, all utilized ammonia and urea nitrogen. Whereas vitamins were unessential for the majority of C. bovis. 18 strains failed to grow in the absence of nicotinic acid; however, for 11 of these Casamino Acids replaced nicotinic acid in supporting growth. Thirteen C. ulcerans strains from aseptically drawn milk, as well as two Type Culture strains (NCTC 7907 and 7908) from the human throat required amino acid nitrogen sources, nicotinic acid, pantothenate and biotin. Some nutritional heterogeneity was shown by 46 strains collectively described as C. lacticum obtained from market milk, milk products and dairy utensils; nevertheless the nutritional differences between the groups of these strains correlated broadly with other distinguishing properties. A group of 9 markedly caseolytic strains required amino acid nitrogen sources, thiamine and biotin, whereas a second group of 30 strains, some utilizing inorganic nitrogen sources, required thiamine and pantothenate, with or without biotin. The remaining C. lacticum strains together with a number of unidentified strains from similar sources were generally slow growing and had widely differing growth requirements.