Showing papers on "B vitamins published in 1982"
TL;DR: This paper aims to demonstrate the efforts towards in-situ applicability of EMMARM, as to provide real-time information about the response of the immune system to antibiotics.
Abstract: 1 Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115 z Houghton Poultry Research Station, Huntingdon, Cambs PE17 2DA, United Kingdom 3 The Wistar Institute, Thirty-Sixth Street at Spruce, Philadelphia, Pennsylvania 19104 4 Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, New York 10016 5 College de France, Laboratoire de M6dicine Exp6rimentale, 11, Place Marcelin-Berthelot, 75231 Paris, Cedex 05, France 6 Institute for General and Experimental Pathology, University of Innsbruck, Fritz-Pregl-Strasse 3, A-6020 Innsbruck, Austria 7 Institute for Experimental Immunology, University of Copenhagen, N0rre Alle 71, DK-2100 Copenhagen 0, Denmark s Department of Immunology and MRC Group of Immunoregulation, University of Alberta, Edmonton, Alberta, Canada 9 Department of Animal Science, Iowa State University, Ames, Iowa 50011 10 Basel Institute for Immunology, Grenzacherstrasse 487, CH-4005 Basel, Switzerland ~1 Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30605 a Department of Medical Microbiology, Turku University, Turku, Finland 20520
186 citations
TL;DR: Findings indicate that MOMPs of different strains of C. trachomatis are antigenically complex and that antigenic heterogeneity exists among the surface-exposed portions of the protein.
Abstract: The major outer membrane proteins (MOMPs) of several Chlamydia trachomatis serotypes (B, D, G, H, and L2) and of the C. psittaci meningopneumonitis strain were purified by preparatory sodium dodecyl sulfate-(SDS)-polyacrylamide gel electrophoresis. The isolated SDS-polypeptide complexes, which varied in their apparent subunit molecular weights, were used as immunogens to raise hyperimmune rabbit antisera. The specificities of these antisera were determined both by rocket immunoelectrophoresis with the soluble SDS-polypeptide complex as antigen and by micro-immunofluorescence with whole organisms. By rocket immunoelectrophoresis, each of the soluble C. trachomatis MOMPs was immunologically related; however, no immunological cross-reactions occurred with the C. psittaci meningopneumonitis polypeptide, indicating that the MOMPs are antigenically distinct among members of these two chlamydial species. The same antisera were highly reactive with intact organisms by micro-immunfluorescence, demonstrating that at least some of the antibodies raised with SDS-polypeptide complexes reacted with native antigenic sites of these surface proteins. By micro-immunofluorescence, anti-MOMP sera remained species specific; but, unlike the results observed by rocket immunoelectrophoresis, distinct differences in the reactivity and specificity of these antisera were observed among C. trachomatis serotypes. C. trachomatis isolates were separated into two distinct serogroups on the basis of their reactivity with anti-MOMP sera. B complex organisms (B, Ba, D, E, F, G, K, L1, L2, and L3) all reacted strongly with anti-MOMP sera of the B, D, G, and L2 serotypes. In contrast, these same antisera were poorly reactive with the C complex serotypes A, C, H, I, and J. Anti-H MOMP serum was the most serospecific, since high-antibody titers were found only against the homologous H serotype organism. These findings indicate that MOMPs of different strains of C. trachomatis are antigenically complex and that antigenic heterogeneity exists among the surface-exposed portions of the protein.
159 citations
TL;DR: Fermented milk products showed an increase in folic acid content and a slight decrease in concentration of vitamin B 12 and orotic acid was reduced in all fermented milk products.
97 citations
TL;DR: This work is the first systematic comparison by serological and histogenetic methods of the allelic products (allomorphs) of 15 haplotypes, including all of the 11 that were accepted as “standard” B haplotypes at the recent international Workshop on the chicken MHC in Innsbruck, Austria.
Abstract: The major histocompatibility complex (MHC) of Gallus gallus is the B complex of which three classes of cell-membrane antigens have been clearly defined by serological, histogenetic, and biochemical methods. Two of these classes are homologous to classes I and II of mammals (B-F and B-L, respectively), while the third (B-G) is a differentiation antigen of the erythroid cell-line; the mammalian homologue of this class is still undefined. The B haplotypes comprise at least one gene of each class that displays linkage disequilibrium of a remarkable strength. The present work is the first systematic comparison by serological and histogenetic methods of the allelic products (allomorphs) of 15 haplotypes, including all of the 11 that were accepted as “standard” B haplotypes at the recent international Workshop on the chicken MHC in Innsbruck, Austria. The analysis has revealed many similarities, but only four pairs of probable identities: G2 and G12, F4 and F13, L4 and L13, L12 and L19. It appears therefore that the B-G locus is comparable in its degree of polymorphism to the class I (B-F) locus. The “standard” haplotypes are almost all of White Leghorn derivation, and preliminary typings of other breeds of chickens, and of wild chickens, indicate the existence of a much wider spectrum of allomorphs.
96 citations
TL;DR: The results indicate that the SCb polypeptides travel cohesively: they all have nearly superimposable distribution profiles at the advancing “front” of theSCb wave of radioactivity, and there is considerable variation among the polypePTides in the portion of the distribution profiles trailing behind the advancing peak and in the breadth of the peak’s crest.
Abstract: The axonal transport of the diverse group of polypeptides characteristic of slow component b (SCb), or Group IV, may be accomplished either by a bulk flow mechanism acting on each of the individual polypeptides or by their movement through the axoplasm as part of a physical complex or structural assembly. In order to determine if the SCb polypeptides travel as a cohesive unit (which would be consistent with the latter alternative above), we examined in detail the quantitative distribution of the individual SCb polypeptides in the guinea pig optic system at three different times after pulse radiolabeling the neuron cell bodies. Eighteen SCb polypeptides were selected as appropriate for analysis. Individual optic systems at the three select times after labeling were harvested, cut into small segments, and subjected to SDS-PAGE. Individual radioactive polypeptide bands were identified and located by fluorography, excised, and then quantified by scintillation counting. The results indicate that the SCb polypeptides travel cohesively: they all have nearly superimposable distribution profiles at the advancing “front” of the SCb wave of radioactivity. However, the distribution profiles are not identical: there is considerable variation among the polypeptides in the portion of the distribution profiles trailing behind the advancing peak and in the breadth of the peak’s crest. This variation is consistent with the hypothesis that the individual polypeptides have differing affinities for an SCb group, or structure, as it moves down the axon. The majority of material transported anterogradely in axons is transported within three distinct axonal transport components. These three components of axonal transport were characterized initially by the rate at which they traversed the axons (as in Grafstein and Forman, 1980); however, recently, the idea has emerged that they also may be structurally and functionally distinct entities (Droz et al., 1975; Lorenz and Willard, 1978; Lasek, 1980; Tytell et al., 1981). The fast component of axonal transport (moving at 250 to 400 mm/day) and the slower component (SCa, moving at 0.2 to 1 mm/day) have both been relatively well characterized by both rate determinations and macromolecular constituents (Ochs, 1972; ’ We gratefully acknowledge the excellent technical assistance of Shirley Ricketts and Diane Filsinger, the assistance of Michael Lark with the computations, and the secretarial skills of Mrs. Ann Martin during the completion of this work. This study was supported by the National Institutes of Health Predoctoral Fellowship HD-07104 to J. A. G. and National Institutes of Health Grants NS 14900-02 and NS 13658-03 to R. J. L. This work has been presented in preliminary form (Garner and Lasek, 1978). ’ Present address: Department of Chemistry, Brain Research Group, Indiana University, Bloomington, IN 47405. Hoffman and Lasek, 1975; Willard et al., 1974; Willard and Hulebak, 1977; Tytell et al., 1981). The fast component contains primarily glycoproteins (Forman et al., 1972), membranes and membrane vesicles (Droz et al., 1975; Tsukita and Ishikawa, 1980), or the materials related to transmitter release (Schwartz et al., 1976; Brimijoin, 1975). SCa, on the other hand, is composed primarily of cytoskeletal proteins, including tubulin and the neurofilament-associated proteins (Hoffman and Lasek, 1975; Lasek and Hoffman, 1975). Its structural counterpart has been suggested to be the axonal cytoskeleton (Lasek, 1980). The third major axonal transport component (at 2 to 4 mm/day) is the component designated SCb (Black and Lasek, 1979, 1980; Brady and Lasek, 1981; Garner and Lasek, 1981) or the Group IV polypeptides (Willard et al., 1974). SCb is extremely complex in constitution, the identity of its constituents ranging from microfilamentassociated proteins, such as actin (Black and Lasek, 1979; Willard et al., 1979), the myosin-like M-2 protein (Willard, 1977), and clathrin (Garner and Lasek, 1981), to many of the metabolic enzymes, such as creatine phosphokinase, nerve-specific enolase, and calmodulin (Brady and Lasek, 1981; Brady et al., 1981).
62 citations
TL;DR: Intensive production of fish in water low in natural food chain organisms amPlifies the importance of providing the dietary requirements for the vitamins listed in Table 1.
Abstract: Vitamins are organic chemical compounds which are required in small amounts for normal growth, reproduction, health, and maintenance of fish metabolism. Eleven water-soluble vitamins and four fat-soluble vitamins are known to be required by salmonids. Compared with most mammals and birds, the gastrointestinal tract of fishes does not contain a rich pattern of established micro-organisms (Margolis, 1953); therefore, it cannot be assumed that the fish obtains appreciable quantities of vitamins from microbial synthesis in the intestine. Transformation of the amino acid, tryptophan, into the vitamin, niacin, is very inefficient in trout and salmon (Poston & DiLorenzo, 1973; Poston & Combs, 1979); therefore, niacin must be included in salmonid feeds. Intensive production of fish in water low in natural food chain organisms amPlifies the importance of providing the dietary requirements for the vitamins listed in Table 1. Vitamins are grouped into the eight water-soluble B vitamins, the macrovitamins L-ascorbic acid, choline and myo-inositol, and the fat-soluble vitamins A, D, E and K. A typical vitamin test diet for fish to control the water-soluble vitamins is listed in Table 2.
42 citations
Journal Article•
TL;DR: It is concluded that, besides binding to the estrogen receptor, the triphenylethylene antiestrogens bind to a specific site distinct from theosterone receptor, that appears to be localized mainly in estrogen target cells.
Abstract: The present paper shows that the antiestrogen tamoxifen and different tamoxifen derivatives bind to two distinct cytoplasmic binding sites in the fetal uterus of guinea pig. The first one (Site A) corresponds to the estrogen receptor and binds tamoxifen with a dissociation constant (Kd) of 1.8 +/- 0.4 nM. The dissociation rate constant (k-1) of th Site A:tamoxifen complex at 4 degrees is 8.3 +/- 2 x 10(-4) sec-1 and at 26 degrees is 123 +/- 26 x 10(-4) sec-1. The binding ability of Site A appears to be thermolabile, being destroyed by heating at 37 degrees. The hydroxylated derivatives of tamoxifen (Metabolites B and D) have a higher affinity for Site A as compared to tamoxifen. The second binding site for tamoxifen (Site B) appears to be specific for the triphenylethylene class of antiestrogens (nafoxidine and several tamoxifen metabolites), the hydroxylation of tamoxifen decreasing the affinity for Site B. In contrast, natural and synthetic estrogens as well as cortisol, testosterone, and progesterone do not compete for Site B. Site B shows a higher affinity for tamoxifen (Kd 0.39 +/- 0.01 nM) as compared to Site A and a higher stability of the complex at both 4 and 26 degrees (k-1 0.81 +/- 0.14 and 3.0 +/- 0.4 x 10(-4) sec-1, respectively). The binding ability of Site B appears to be resistant to heating at 37 degrees. Both Sites A and B are destroyed by proteolytic treatment and are precipitated by 36% saturated ammonium sulfate. The tamoxifen:Site A complex translocates into the uterine nuclei in a "cell free" system by a temperature-dependent process, but the tamoxifen:Site B complex does not. Nevertheless, a site with a Kd similar to cytoplasmic Site B (0.47 +/- 0.1 nM) is spontaneously present in untreated fetal uterine nuclei. In other fetal organs which contain no estrogen receptor (heart) or very low levels (lung), the concentration of Site B is found to be significantly lower than in the fetal uterus (5 to 6 times). Furthermore, progressively lower levels of Site B are found in neonatal, immature, and mature uteri (as compared to fetal uterus) which contain also decreasing amounts of estrogen receptors. It is concluded that, besides binding to the estrogen receptor, the triphenylethylene antiestrogens bind to a specific site distinct from the estrogen receptor, that appears to be localized mainly in estrogen target cells.
41 citations
TL;DR: Camm et al. as mentioned in this paper showed that the chlorophyll a b light-harvesting complex (LHC) from the green alga Acetabularia yields two green bands which run at the position typical of the monomer (CP II).
41 citations
TL;DR: It now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, the authors have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA.
38 citations
TL;DR: In this article, Thurnauer et al. used time-resolved electron spin echo (ESE) measurements on chloroplast preparations and whole cells of photosynthetic algae.
38 citations
TL;DR: The experience suggests that the hyperkinetic cerebral dysfunction syndrome is multifactoral, with half the children found to be “dependent” on pharmacological doses of thiamin worsened with administration of B6.
Abstract: One hundred children with hyperkinesis and cerebral dysfunction were given individual three-day trials of pharmacologic doses of thiamin, calcium pantothenate, pyridoxine, and placebo. When beneficial response was noted, a second week-long trial of vitamins was given, alternating with placebo, followed by long-term therapy. Two-thirds of the remaining children not responding to this schedule were then given pharmacologic doses of niacinamide, combinations of B-complex vitamins, or elimination diets.Eight children dramatically responded to pharmacologic doses of thiamin, of which four still require the vitamin either intermittently or continuously after four years. Nine children responded to 300 mg of pyridoxine; an additional 5 patients responded only after receiving larger doses. Only one child could be maintained on placebo.In subsequent trials, 11 responded to niacin or to combinations of B-complex vitamins with minerals. In a two-year follow-up, six children who had demonstrated no beneficial response...
TL;DR: The effects of preweaning and posttransit B-vitamin supplementation on calf health, performanee and blood components were studied with 186 feeder steer calves from eight Tennessee farms.
Abstract: Summary The effects of preweaning and posttransit B-vitamin supplementation on calf health, performanee and blood components were studied with 186 feeder steer calves from eight Tennessee farms. At each farm, one-half of the calves were weaned and fed a 50% concentrate diet for 30 d before being moved to an auction barn (PW). The remaining calves stayed with their dams until the day they were moved to the auction barn. All calves went through the same auction barn-orderbuyer barn conditions before transport to Texas. At the feedlot, calves were fed a B-vitamin supplement at one of three levels (none, medium and high). PW calves gained 5 kg (P<.05) more than the control calves at the farm of origin. Total marketing and transit weight losses were similar for both groups. During the first month in the feedlot, PW calves consumed more feed (P<.05), gained more slowly (P<.10) and had poorer feed conversions (P<.05) than control calves. After 2 mo in the feedlot performance was similar for both groups. Calves fed the medium B-vitamin level had poorer feed conversions (P<.05) after 2 mo in the feedlot than control calves or calves fed the high B-vitamin level. Morbidity and mortality rates were not significantly affected by treatments, although PW calves
TL;DR: A previously unreported condition was observed in which birds died showing post-mortem signs characteristic of both FLKS and SDS and whose occurrence was related to the biotin status of the chicks.
Abstract: 1. Addition of supplemental choline to a biotin-deficient diet decreased the biotin status of chicks and increased mortality from fatty liver and kidney syndrome (FLKS). 2. Mortality was also increased by dietary supplementation with a mixture of other B-vitamins, excluding biotin, and was highest when the choline and B-vitamin supplements were combined. 3. The occurrence of sudden death syndrome (SDS) was unaffected by dietary biotin concentration. 4. A previously unreported condition was observed in which birds died showing post-mortem signs characteristic of both FLKS and SDS and whose occurrence was related to the biotin status of the chicks.
TL;DR: In this paper, the enthalpies of formation of three manganese borides have been measured by solution calorimetry in liquid copper at 1386 K, and the following results are reported: αH f ( 1 3 Mn 2 B) = − (31.7±2.0)kJ ·mol −1, αH F ( 1 2 MnB) = - (35.8±2).4)kj ·mol−1, and αHF f (1 2 Mn B 2 ) = −(21.1±
TL;DR: Functional impact of vitamin supplements may be seen even in the absence of clear-cut clinical or biochemical change.
Journal Article•
TL;DR: National average intakes were found to be biotin distributions could also be made to the intake of the B vitamins by alcoholic drinking and confectionery, and suggested recommended intakes values were rather low.
Abstract: Intakes of biotin, pantothenic acid and vitamin E in Britain were calculated by applying values from the 4th edition of McCance and Widdowson's The composition of foods or other published values to the amounts of food recorded in the National Food Survey of 1979. National average intakes were found to be biotin distributions could also be made to the intake of the B vitamins by alcoholic drinking and confectionery. Comparison of intakes with suggested recommended intakes values were rather low while for pantothenic acid the recommendations were met.
TL;DR: The B-complex vitamin content, appearance, texture, and flavor of sour cream made by the direct acidification and culture processes were compared by a semi-trained panel of judges as mentioned in this paper.
TL;DR: Resistance within B5B5 genotypes appears to be associated with genetic interaction between two T cell antigen loci, which are not linked with the B complex.
TL;DR: Cell suspension cultures were established from the callus proliferation of leaf explants of 10- to 12-day-old seedlings of the peanut (Arachis hypogaea L. var. TMV-3) and were dependent on exogenous supply of HCO(3) (-).
Abstract: Cell suspension cultures were established from the callus proliferation of leaf explants of 10- to 12-day-old seedlings of the peanut ( Arachis hypogaea L. var. TMV-3). The cells could be cultivated in both agitated and still media, the latter promoting more of chlorophyll (Chl) synthesis. High Chl content (210-240 micrograms Chl per gram fresh weight), yield of free and pipetable cells, presence of all the pigments in the same ratio as that of the leaf tissue, and high rates of O 2 evolution (140-170 micromoles O 2 per milligram Chl per hour) were some of the desirable features of the still-grown cell cultures. However, considerable variations with regard to the above characters were observed between the cell cultures of different varieties of the peanut. O 2 evolution by the cultured cells was dependent on exogenous supply of HCO 3 − . A well-developed photosynthetic apparatus as evidenced from photosystem I and photosystem II activities of the isolated chloroplasts and variable fluorescence measurements with the cell cultures was further documented by electron microscopic evidence of distinct granal stackings in chloroplasts and sodium dodecyl sulfate-polyacrylamide gel separation of thylakoid membranes into P700 Chl a protein complex and light-harvesting Chl a/b complex. Evidence is presented for the relative increase in the Chl associated with P700 Chl a protein complex in contrast to the light-harvesting Chl a/b complex in the cultured cells as compared to intact leaf.
01 Dec 1982
TL;DR: It is observed that photosynthesis and vitamin synthesis go hand-in-hand showing close correlation, and the results indicate that there is a close relation between chlorophyll content and vitamin content.
Abstract: The photosynthetically efficientC 4 plantsviz Amaranthus viridis, Euphorbia hirta and aC 3 plant,Acalypha indica with mosaic leaf pattern showed the maximum amount ofB vitamins when compared to the otherC 3 plants. It is observed that photosynthesis and vitamin synthesis go hand-in-hand showing close correlation. The results also indicate that there is a close relation between chlorophyll content and vitamin content. However, there appears to be no relation between phyllotaxy and photosynthesis. Between the twoC 3 plants,viz., Acalypha andCarica, the photosynthetic inefficiency of the latter might be due to more of chlorophyllb and less of chlorophylla as seen from chlorophylla/chlorophyllb ratios.
Journal Article•
TL;DR: In this paper, it was found that the contents of B-vitamins somewhat decreased according to processing methods, washing-dried and steaming-dry of fresh ginseng.
Abstract: B-vitamin contents in ginsengs ranged from 55.9 to 65.5 r/g and from 13.2 to 14.5 r/g for niacin and niacin amide, from 4.9 to 5.4 mr/g for cobalamine, and from 3.9 to 8.2 r/g and from 6.9 to 8.2 r/g for riboflavin and thiamine regardless processing. Especially, cobalamine was detected in ginseng. It is found that the contents of B-vitamins somewhat decreased according to processing methods, washing-dried and steaming-dried of fresh ginseng. Niacin, niacin amide and cobalamine decreased by . Therefore, it is approved that B-vitamins were stable in processing methods.
TL;DR: This short series of articles on the B vitamins with a description of these two substances describes the phytochemical properties of B vitamins A and B6.
Abstract: We conclude this short series of articles on the B vitamins with a description of these two substances
01 Jan 1982
TL;DR: It is postulated that low anti-sarcoma response associated with MD susceptible lines may result from environmental exposure to MD and subsequent immunosuppression in spite of vaccination for MD at hatching.
Abstract: The MHC of the chicken (B complex) has been shown to exert a decisive influence on the fate of Rous sarcoma virus (RSV)-induced tumors. However, noninbred chickens with identical B genotypes and inbred lines indistinguishable at the MHC have demonstrated considerable variation in response to RSV challenge. The major objective of this research was to determine the cause of variation in anti-Rous sarcoma response observed among chickens with "identical" B genotypes. Chickens were evaluated for anti-tumor response following wingweb inoculation with RSV at six weeks of age. A comparison of anti-sarcoma responses of (15I-5 x 6-1)F1 versus (15I-5 x 7-2)F1 chickens revealed rapid regression among the (15I-5 x 6-1)F1's and tumor progression among the (15I-5 x 7-2)F1's. A three way cross between (15I-5 x 6-3)F1's and line 7-2 produced B2/B2 and B2/B15 progeny. B2/B15 chickens from this cross, identical at the B complex to the (15I-5 x 7-2)F1 progressors, were characterized by tumor regression. Therefore a non-MHC influence associated with the line 7-2 background appeared to suppress anti-sarcoma response. Similar findings were obtained using F2 and backcross progeny of lines 100 and UNH 105, low response being associated with the line 100 background. Both lines 7-2 and 100 are susceptible to Marek's disease (MD). Histological evidence for MD involvement was obtained from bursal sections of chickens that had died of progressive sarcoma growth. It is postulated that low anti-sarcoma response associated with MD susceptible lines may result from environmental exposure to MD and subsequent immunosuppression in spite of vaccination for MD at hatching. If low anti-sarcoma response associated with lines 100 and 7-2 is a result of immunosuppression by MD virus, then non-MHC genetic background would appear to be a strong factor influencing relative susceptibility to MD.
01 Jun 1982
TL;DR: Vitamins of the B groupviz.
Abstract: Kinetin (50 and 100 mg 1−1) inhibited both the shoot and the root growth. Inhibition of root growth by kinetin is considered to be mainly due to inhibition of protein synthesis. Vitamins of the B groupviz., riboflavin, thiamin, niacin and pantothenic acid are found to be antagonistic to kinetin in reversing the inhibition of protein synthesis of the root. Vitamins, probably by acting as inducers of protein synthesis, antagonized the action of kinetin. The response of kinetin to shoot protein content is different from that of the root.
TL;DR: This investigation of dietary choices of 70 recovering (abstinent) alcoholics who lived in a halfway house but who ate and worked elsewhere everyday concluded that their freely chosen diet resembles that of non-alcoholic adult Americans.
TL;DR: The nutritional adequacy of commercial baby foods is assessed from data derived from a longitudinal nutrition survey of 400 infants in Canada, finding that on the average, the nutrient intakes from infant food meet or exceed the recommended daily allowances for most nutrients.
Abstract: The nutritional adequacy of commercial baby foods is assessed from data derived from a longitudinal nutrition survey of 400 infants in Canada. On the average, the nutrient intakes from infant food meet or exceed the recommended daily allowances for most nutrients. Most infants would not be able to meet the minimum daily requirements for iron, B vitamins, or calcium if infant cereals were not fortified.
TL;DR: In this paper, Goldberger showed that the anti-beri−beri factor was more stable to heat than the water soluble B factor and called it the pellagra-preventive, or P•P factor.
Abstract: In the last article we saw how Goldberger, in 1926, demonstrated that the ‘Water soluble B’ factor of McCollum and Davies contained more than one vitamin. He showed that pellagra was associated with the lack of a vitamin and that the latter was distributed in a somewhat similar manner to the anti‐beri‐beri factor. However, Goldberger demonstrated that there was an essential difference between the two factors: the one preventing pellagra was more stable to heat. He called it the pellagra‐preventive, or P‐P factor.
01 Jan 1982
TL;DR: Protocorms, and to a lesser degree very young shoots of Cymbidium, are excellently suited for the conventional techniques of vegetative propagation because they possess a high potential for regeneration.
Abstract: It is an established fact that the cultivation of explants from monocotyledonous plants is more difficult than from dicotyledonous. This is certainly true for most orchids, although it is possible to excise and culture successfully parts of individuals from a few genera including the genus Cymbidium. It has also been shown that explanted floral meristems and protocorms can be cultured on a simple medium containing B vitamins. It is thought that the B vitamins replace the nutrient contribution from the symbiotic fungus which normally grows in close association with the plant. Cultures of several Cymbidium species have been initiated from the main bud and ‘side meristems’ or buds of the so-called ‘pseudo bulbs’ which develop at the base of the shoot of adult plants. During culture these ‘meristems’ pass through a developmental sequence similar to that of an orchid embryo during seed germination. A protocorm stage can be clearly distinguished and this is followed by the development of a plantlet. Protocorms, and to a lesser degree very young shoots of Cymbidium, are excellently suited for the conventional techniques of vegetative propagation because they
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Fig. 10.1
Items for the sterile transfer room
possess a high potential for regeneration.
TL;DR: The discovery of these vitamins is described, together with a more detailed description of vitamin B1, in this issue of Nutrition Letters.
Abstract: This is the first of a short series of articles on the B vitamins. In this issue the discovery of these vitamins is described, together with a more detailed description of vitamin B1.