Showing papers on "B vitamins published in 1984"

Herbicide resistance in Chlamydomonas reinhardtii results from a mutation in the chloroplast gene for the 32-kilodalton protein of photosystem II.

Abstract: We report the isolation and characterization of a uniparental mutant of Chlamydomonas reinhardtii that is resistant to 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine). Such herbicides inhibit photosynthesis by preventing transfer of electrons in photosystem II from the primary stable electron acceptor Q to the secondary stable electron acceptor complex B, which is thought to contain a protein of 32 kDa and a bound quinone. It has been proposed that herbicide binding to the 32-kDa protein alters the B complex so that electron transfer from Q is prohibited. Both whole and broken-cell preparations of the mutant alga show a resistance to the effects of herbicide on electron transfer from Q to B, as measured by fluorescence-induction kinetics. In the absence of herbicide, mutant cells exhibit a slower rate of Q to B electron transfer than do wild-type cells. The 32-kDa protein from wild-type cells, but not mutant cells, binds azido[14C]atrazine at 0.1 μM. We have isolated psbA, the chloroplast gene for the 32-kDa protein, from both wild-type and herbicide-resistant algae and sequenced the coding regions of the gene that are contained in five exons. The only difference between the exon nucleotide sequences of the wild-type and mutant psbA is a single T-A to G-C transversion. This mutation results in a predicted amino acid change of serine in the wild-type protein to alanine in the mutant. We suggest that this alteration in the 32-kDa protein is the molecular basis for herbicide resistance in the C. reinhardtii mutant.

Differential regulation of the accumulation of the light‐harvesting chlorophyll a/b complex and ribulose bisphosphate carboxylase/oxygenase in greening pea leaves

Abstract: The photoregulation of chloroplast development in pea leaves has been studied by reference to three polypeptides and their mRNAs. The polypeptides were the large subunit (LSU) and the small subunit (SSU) of ribulose 1,5-bisphosphate carbox-ylase/oxygenase (RUBISCO), and the light-harvesting chlorophyll a/b protein (LHCP). The polypeptides were assayed by a sensitive radioimmune assay, and the mRNAs were assayed by hybridization to cloned DNA probes. LSU, LSU mRNA, and LHCP mRNA were detectable in etiolated seedlings but LHCP, SSU, and SSU mRNA were at or below the limit of detection. During the first 48 hr of de-etiolation under continuous white light, the mRNAs for LSU, SSU, and LHCP increased in concentration per apical bud by about 40-fold, at least 200-fold, and about 25-fold, respectively, while the total RNA content per apical bud increased only 3.5-fold. In the same period, the LSU, SSU, and LHCP contents per bud increased at least 60-, 100-, and 200-fold, respectively. The LHCP increased steadily in concentration during de-etiolation, whereas the accumulation LSU, SSU, and SSU mRNA showed a 24-hr lag. The accumulation of SSU, SSU mRNA, and LHCP mRNA showed classical red/far-red reversibility, indicating the involvement of phytochrome in the regulatory mechanism. LSU and LSU mRNA were induced equally well by red and far-red light. The LHCP failed to accumulate except under continuous illumination. These results indicate that the accumulation of SSU is controlled largely through the steady-state level of its mRNA, which is in turn almost totally dependent on light as an inducer and on phytochrome as one of the photoreceptors. The accumulation of LSU is largely but not totally determined by the level of its mRNA, which appears to be under strong photoregulation, which has yet to be shown to involve phytochrome. Phytochrome is involved in the regulation of LHCP mRNA levels but substantial levels of the mRNA also occur in the dark. LHCP accumulation is not primarily governed by the levels of LHCP mRNA but by posttranslational stabilization in which chlorophyll synthesis plays a necessary but not sufficient role.

Cytogenetic studies of some species complexes of Anopheles in Thailand and Southeast Asia.

Abstract: Recent studies on cytogenetics, behavioral, geographical and distinct morphological characters on adult, pupal and larval stages have revealed that "balabacensis" is a species complex. Anopheles dirus the mainland species, is distributed widely in Thailand and is renowned for its role as primary vector of human malarial parasites. Further, evidence from cytogenetic and taxonomic studies suggests that "An. dirus" is a species complex comprising at least four distinct species provisionally designated: dirus A, B, C and D. These cryptic species are distinguishable only partially morphologically, but can be separated on the basis of metaphase chromosomes using the Giemsa and Hoechst 33258 staining techniques. Apparently, these siblings show distinct patterns of geographic distribution in Thailand and Peninsular Malaysia. The recognition of dirus as a complex of species in Thailand and Peninsular Malaysia requires a re-evaluation of the role that the individual members of this complex have in the transmission of malaria parasites in this region. Cytological analysis of gene rearrangements in ovarian polytene chromosomes has shown that An. maculatus is a sibling-species complex consisting of at least four species in Thailand provisionally designated: maculatus A, B, C and G. These siblings are sympatric in some populations. Furthermore, species B is so highly polymorphic for chromosome rearrangements that four geographic forms can be recognized. It is not known whether these four forms are subspecies or yet further species within the species B complex. These sibling-species must be differentiated in order to understand any differential capabilities in their transmission of human malaria parasites. Anopheles nivipes was elevated from synonymy under An. philippinensis to full species status by Reid, a decision recently confirmed by cross mating experiments. The Thailand Malaria Division does not differentiate these two species and only identifies An. philippinensis, yet, An. nivipes is by far the most common of the two species in Thailand. Furthermore, preliminary surveys of the ovarian polytene chromosomes of several widely separated populations of An. nivipes in Thailand have revealed at least two distinct chromosomal types of nivipes based on fixed inversions on the X chromosomes.

Certain B vitamin and phytic acid contents of pearl millet [Pennisetum americanum (L.) Leeke]

Abstract: The overall range in B vitamins of pearl millet, 100 lines from each of 4 locations, was riboflavin 1.8-2.6, niacin 25-57 and thiamin 3.8-8.8 μg/g. Little variation occurred in riboflavin and thiamin contents among cultivars grown at the same location but niacin varied significantly among cultivars from the same location. Location had a strong effect on thiamin, a moderate effect on niacin and no significant effect on riboflavin content. Significant losses of B vitamins occurred after milling. Amounts of vitamins were high in the germ and bran but relatively low in endosperm. Cooked millet had higher vitamin contents, presumably due to improved extractability. The content of phytic acid in millet was slightly lower than that reported for wheat and seemed to vary both with location and with cultivar. Germ was rich and endosperm poor in phytic acid.ADDITIONAL ABSTRACT:Little variation occurred in riboflavin and thiamin contents among P. americanum cv. grown at the same location, but niacin content varied significantly. Location had a strong effect on thiamin content, a moderate effect on niacin and no significant effect on riboflavin content. All 3 substances were high in the germ and bran portions of the seeds but low in the endosperm. Phytic acid levels were slightly lower than those reported for wheat and appeared to vary both with location and with cv.

Nutrient content of liquid milk: I. Vitamins A, D3, C and of the B complex in pasteurized bulk liquid milk

Abstract: A survey was undertaken to update and extend available information on the vitamin content of pasteurized milk as produced at processing dairies in mainland UK and to investigate regional, seasonal and breed effects. The concentration of total retinol in milk from non-Channel Island (NCI) breeds averaged 61·9 βg/100g in summer and 41·2 βg/100g in winter. Concentrations of β-carotene were 31·5 and 10·5 βg/100g in summer and winter respectively. Concentrations of retinol in milk from Channel Island (CI) breeds were similar, but concentrations of β-carotene were on average 3 times higher. The concentration of vitamin D 3 in milk from NCI breeds was 0·033 βg/100g in summer and 0·026 βg/100g in winter. There was no marked seasonal variation in the mean concentration of total vitamin C (14·5 βg/ml). Values for the concentration of B vitamins (βg/ml) were: folic acid 0·060, vitamin B 12 0·0042, riboflavin 1·78, nicotinic acid 0·71, pantothenic acid 3·60, biotin 0·020, thiamin 0·46 and vitamin B 6 0·61. Seasonal variation in the concentration was most marked for folic acid (c.v. 17·4%) and to a lesser extent for vitamin B 12 (c.v. 10·3%). The only breed differences in the B vitamin content were for riboflavin and folic acid, the mean values obtained for milk from CI breeds being respectively 20 and 10 % higher than those from NCI breeds.

Newer Laboratory Methods for Assessing Nutriture of Selected B-Complex Vitamins

Abstract: This review is limited to progress in the development of new or improved laboratory procedures to assess the nutriture of thiamin, riboflavin, niacin, vitamin B6, and folic acid. There has been marked progress in this area for the other vitamins as well. The increased availability of radioassay techniques and HPLC methodologies that have application in nutrition assessment is significant. However, for a number of the vitamins, there is still a need for additional methods that provide functionally interpretable preclinical information and give accurate assessment of body reserves of the nutrient. Often the guides used to interpret the information obtained are tentative and require validation or revision. This situation is further complicated by the frequent lack of suitable reference standards for quality controls and interlaboratory validation.

Reconceptualizations and Interfield Connections: The Discovery of the Link between Vitamins and Coenzymes

Abstract: The discovery that some B vitamins are constituents of respiratory coenzymes led to the development of an interfield theory of the kind discussed by Darden and Maull (1977). In this paper it is shown that the development of a useful interfield connection was made possible by two reconceptualizations: (1) a reconceptualization that united two then-distinct fields giving rise to the concept of vitamins as dietary substances; and (2) another reconceptualization that united two approaches to respiratory metabolism producing the idea that coenzymes are transport vehicles.

B‐Vitamin Content of Natural Lactic Acid Fermented Cornmeal

Abstract: The content of nine B vitamins was determined in cornmeal after 24,48,72, or 96 hr of natural lactic acid fermentation. Compared to the nonfermented control, all fermented samples had significantly (P < 0.05) increased levels of vitamin Bta, riboflavin, and folacin. Samples fermented 96 hr had significantly (P < 0.05) increased pantothenic acid compared to the control. All fermented samples contained significantly (P < 0.05) less pyridoxine than the control. There were no significant (P < 0.05) differences in niacin and biotin contents. Samples fermented for 24 hr had decreased thiamin and choline compared to the control or to other fermented samples, but there were no other significant (P < 0.05) differences in thiamin and choline contents.

Effect of maternal pyridoxine•HCL supplementation on the vitamin B-6 status of mother and infant and on pregnancy outcome

Abstract: The effect of maternal pyridoxine X HCl (PN-HCl) supplementation on the vitamin B-6 status of pregnant women and their infants at birth and on pregnancy outcome was investigated. Volunteer subjects were randomly assigned a daily vitamin B-6 supplement containing 0, 2.6, 5, 7.5, 10, 15 or 20 mg of PN-HCl in a double-blind study. The mean dietary vitamin B-6 intake of the group was 1.43 +/- 1.28 mg/day as estimated from 24-hour dietary recalls. Maternal plasma pyridoxal 5'-phosphate (PLP) levels were positively correlated with vitamin B-6 supplementation at 30 weeks gestation (r = 0.55, P less than 0.0005) and at delivery (r = 0.54, P less than 0.01). Cord plasma PLP levels reached a maximum when maternal PN-HCl supplementation was 7.5 mg and greater. Supplemental PN-HCl at the 7.5-mg level was required to prevent a decrease in maternal plasma PLP at delivery. Apgar scores at 1 minute after birth were higher (P less than 0.05) for infants whose mothers took 7.5 mg or more supplemental PN-HCl than for infants of mothers who took 5 mg or less. These findings indicate that a vitamin B-6 intake between 5.5 and 7.6 mg/day (diet plus supplement as pyridoxine equivalents) was required to maintain maternal plasma PLP levels at term at a level comparable to initial values.

Vitamin therapy in the absence of obvious deficiency: what is the evidence?

Abstract: Vitamins are a group of organic compounds occurring naturally in food and are necessary for good health. Lack of a vitamin may lead to a specific deficiency syndrome, which may be primary (due to inadequate diet) or secondary (due to malabsorption or to increased metabolic need), and it is rational to use high-dose vitamin supplementation in situations where these clinical conditions exist. However, pharmacological doses of vitamins are claimed to be of value in a wide variety of conditions which have no, or only a superficial, resemblance to the classic vitamin deficiency syndromes. The enormous literature on which these claims are based consists mainly of uncontrolled clinical trials or anecdotal reports. Only a few studies have made use of the techniques of randomisation and double-blinding. Evidence from such studies reveals a beneficial therapeutic effect of vitamin E in intermittent claudication and fibrocystic breast disease and of vitamin C in pressure sores, but the use of vitamin A in acne vulgaris, vitamin E in angina pectoris, hyperlipidaemia and enhancement of athletic capacity, of vitamin C in advanced cancer, and niacin in schizophrenia has been rejected. Evidence is conflicting or inconclusive as to the use of vitamin C in the common cold, asthma and enhancement of athletic capacity, of pantothenic acid in osteoarthritis, and folic acid (folacin) in neural tube defects.

Composition for detoxification

Abstract: Compositions for use in and a method for detoxifying chronic alcoholics and hard-line drug addicts while avoiding all of the major symptoms associated with alcohol and/or drug withdrawal, which comprises administering orally to such a subject an effective amount of a formulation in dosage unit form having the following composition: 5-50 grams of at least one magnesium salt selected from the group consisting of magnesium chloride, magnesium sulfate, magnesium citrate and other suitable magnesium salts; 500 mgms. to 2 grams of at least one potassium salt selected from the group consisting of potassium citrate, potassium sulfate, potassium chloride, potassium bromide, potassium bitartrate and other suitable potassium salts; and 50 mgms. to 5 grams of at least one salt selected from the group consisting of the citrates, ascorbates, chlorides, bromides, sulfates, carbonates, gluconates, lactates and bitartrates of calcium, sodium, zinc, copper and lithium. The compositions can additionally contain vitamins, particularly the B vitamins, nutrients, sugars, flavoring and coloring agents, and are provided in powder form. Just prior to use, the compositions are introduced into a suitable diluent, preferably water in an amount suitable for dissolving all of the powder and for being administered as a single dosage unit or may be provided for administration in the form of a prepared liquid.

Functional and inducible expression of a transfected murine class II major histocompatibility complex gene.

Abstract: Using the spheroplast fusion technique, we have introduced the cloned E beta b gene into two d haplotype cell lines, the B lymphoma line A20-2J and the macrophage tumor line P388D1. Analysis with a monoclonal antibody indicates that the product of the transfected E beta b gene associates with the endogenous E alpha chain to form an E alpha dE beta b complex. While expression of E alpha dE beta b is constitutive in A20-2J cells transfected with the E beta b gene, surface expression of E alpha dE beta b is detected in transfected macrophage cells only after treatment of cells with culture supernatants from concanavalin A (Con A)-stimulated T cells. Transfected B lymphoma cells and transfected Con A supernatant-treated macrophage cells have acquired the ability to present antigen to E alpha dE beta b-restricted T-cell hybridomas. The observed inducible expression of the transfected gene in the macrophage host indicates that sequences responsible for regulated expression of the E beta b gene may be associated with the transfected gene. In combination with directed mutagenesis, the system described here provides a means to study (i) E beta b sequences that are important in determining the restriction specificity of the E molecule and (ii) sequences associated with the E beta gene that may be important in the regulation of E beta chain expression.

Resistance to Marek's disease is controlled by a gene within the B-F region of the chicken major histocompatibility complex in Rous sarcoma regressor or progressor inbred lines of chickens.

Abstract: Rous sarcoma "regressor" chicken lines CB and CB.R1 identical in the B-F region of the B complex (MHC) are susceptible to Marek's disease. On the contrary, the Rous sarcoma "progressor" line CC different in the B-F region from the CB and CB.R1 lines and identical in the B-G region with the CB.R1 line is considerably resistant to MD. The inbred chicken line M is susceptible to MD, although it carries the B21 allele which is generally considered to determine MD resistance. Analysis by means of sera specific for B-F and B-G antigens revealed that the B haplotype of the M line is composed of the B-G region coding for the typical B-G21 antigen and of a different B-F region coding for B-Fx antigen of thus far unknown specificity. Thus genetic resistance to MD is controlled by a gene located within the B-F region of the chicken MHC.

Dietary intakes of preschoolers.

Abstract: Between 1977 and 1979, the H.J. Heinz Company of Canada Ltd conducted a longitudinal survey of infant nutrition from birth to 18 months. In 1980, 189 of the original 403 infants were recruited in a follow-up study. The age of the children in the follow-up study was 3.5 to 4 years. This article describes the food and nutrient intakes of the preschool children. Food intake information was obtained by the 4-day dietary record method. The mean energy intake of the children was adequate to support normal growth. The mean nutrient intakes were above the recommended daily intakes of the Canadian Dietary Standard. All children ate three regular meals and at least one in-between meal snack. Milk was the primary source of energy, protein, fat, calcium, phosphorus, sodium, potassium, and riboflavin. Meat contributed a substantial amount of protein, fat, and niacin. Cereal and cereal products were the primary source of iron and were good sources of carbohydrates, sodium, and the B vitamins. Fruit and fruit juices were the primary sources of carbohydrate and vitamin C. Vitamin supplements provided large amounts of vitamin A and the B vitamins. Since foods alone included sufficient nutrients to provide the recommended daily nutrient intakes, vitamin supplements were largely unnecessary.

Comparison of three geometries for a cesium primary beam liquid secondary ion mass spectrometry source.

Abstract: Etude de deux nouvelles configurations faisceau ionique primaire/faisceau ionique secondaire. Resultats obtenus avec la vitamine B 12 et la Met-Lys-bradykinine

Syngeneic lines of chickens. VII. The lines derived from the recombinants at the B complex (MHC) of Rous sarcoma regressor and progressor inbred lines of chickens.

Abstract: Based on recombinants between the B haplotypes of chickens of inbred lines CB, CC, and CB.I-B7, three new inbred lines homogeneous in transplantation and erythrocyte antigens were established by backcrossing. These newly established recombinant lines, CB.R1, CC.R1, and CC.R2, together with the original inbred lines, which differ at the B complex (MHC) and in the degree of genetically controlled resistance to progressive growth of RSV-induced tumours, represent a model system for study of the structure of the B complex and of the functions of individual B regions in the control of carcinogenesis.

Liquid chromatographic determination of vitamin B-6 in foods

Abstract: Chromatographic analysis for vitamin B-6 in complex samples imposes certain requirements on the analyst, who must extract completely the bound, unstable vitamers without loss, remove interfering compounds, and provide clean extracts for analysis. The analyst also has to contend with the problems inherent in all methods, such as sample collection, storage, preparation, and homogenization. However, chromatography provides a means of identifying and quantitating all forms of the vitamin, and thus provides the possibility of addressing the problem of the bioavailability of specific vitamers. It also allows automation, which is absolutely essential in coping with the large numbers of samples that are generated in areas such as quality control. These factors are all addressed here, and chromatographic results for various meat and other food products are presented to illustrate the variations in vitamin content that occur from sample to sample, the agreement with microbiological results, and that liquid chromatography (LC) has come of age in dealing with complex biological samples, such as food and food products.

Quality Attributes and Retention of Selected B-Vitamins of Canned Faba Bean as Affected by Soaking Treatments

Abstract: Solutions of ethylenediamine tetraacetic acid and sodium bicarbonate were used to soak faba beans before canning. Soaking in ethylenediamine tetraacetic acid solutions only caused a slightly lighter bean color. Soaking in bicarbonate solutions increased both the drained weight and the softness of the cooked beans, and it also made the bean color darker. The profiles of loss of both thiamin and riboflavin during the canning process were determined. Riboflavin was lost primarily during retorting while thiamin was lost in several processes including heat pretreatment and soaking. Mechanism of loss for the two vitamins was mainly leaching; very little thermal destruction was observed. None of the soaking treatments affected the retention of these vitamins.

MHC‐ and non‐MHC‐encoded surface antigens of chicken lymphoid cells and erythrocytes recognized by polyclonal xeno‐, allo‐ and monoclonal antibodies

Abstract: Surface antigens on chicken thymus and bursa cells were analyzed by immunoprecipitation using polyclonal and monoclonal antisera raised against (and specific for) thymus (ATS) or bursa (ABS) cells, respectively. The antigens identified were compared with those governed by the B-F, B-L and B-G regions of the chicken major histocompatibility complex (B complex). Four proteins were precipitated from thymus cells by 2 polyclonal ATS: both antisera recognized molecules of apparent molecular mass of 172–182, 132–135, 75–76 kDa, and one antiserum in addition recognized a protein of 102 kDa. The 172–182 and 102-kDa peaks were still demonstrable under reducing conditions indicating that they are composed of a single polypeptide chain, the other 2 were lost under reducing conditions, therefore, must be composed of smaller subunits. Of the 2 monoclonal ATS tested, one identified a single protein of 186 kDa and the other a 135-kDa protein (in addition to 2 smaller molecules); whether these are the same as those precipitated by the polyclonal antisera remains to be determined as they behaved differently under reducing conditions. Proteins of 162 and 78–84 kDa were revealed by 2 polyclonal ABS under nonreducing conditions but the former may in one case be a polymer (it disappeared under reducing conditions) and in the other a single molecule. In addition molecules of 182 kDa were identified by one antiserum and of 84 and 60 kDa by the other under nonreducing conditions. Of the 4 monoclonal ABS only one identified a 200-kDa protein: molecules of 115–125, 90–100, 48–52 and 40–43 kDa were also precipitated, all of which were reduced to smaller molecules. With 2 specific anti-B-F alloantisera we were able to precipitate the “conventional” B-F antigen from red blood cell lysates of CB-strain chickens resolving into a 40-kDa peak and a light chain of about 12 kDa corresponding to β2 microglobulin. Precipitates from peripheral blood lymphocytes, bursa and thymus cells revealed an additional protein of 22 kDa. With 2 specific B-L alloantisera two peaks of 33 kDa and 31 kDa were obtained from peripheral blood lymphocytes. Using anti-B-G alloantisera a double band corresponding to 47 and 42 kDa was seen under reducing conditions. There is no evidence from these data to indicate that the polyclonal and monoclonal antibodies are directed towards major histocompatibility complex antigens.

Composition and method for stimulation of bacteria

Abstract: Composition for stimulation of .[.aerobic.]. bacteria in sewage or in soil from combination of B vitamins and an agent derived from digestion of milch cow excrement; and method of treating sewage or soil to stimulate the growth of .[.aerobic.]. bacteria to improve the condition of sewage for disposal or availability of soil nutrients for plant growth by addition of the composition to sewage or soil.