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1.
Summary A morphologically distinct variety of Athyrium distentifolium called A. distentifolium var. flexile has been found only in Scotland. Research was undertaken for aUK Biodiversity Action Plan. To confirm that this taxon has a definitely recognisable morphology, a morphometric analysis was used on the range of characters used to define this variety. It showed that it can be clearly differentiated. 相似文献
2.
K.G. Mansfield N.W. Lerche M.B. Gardner A.A. Lackner 《Journal of medical primatology》1995,24(3):116-122
Abstract: A cohort of rhesus macaques (Macaca mulatta), obtained from the California Regional Primate Research Center (CRPRC) and necropsied in 1970–72 with lesions suggestive of simian immunodeficiency virus (SIV) infection, was identified at the New England Regional Primate Research Center (NERPRC). Polymerase chain reaction (PCR), DNA sequence analysis, and in situ hybridization were used to confirm the presence of SIV nucleic acids. This represents the earliest case of SIV infection at the NERPRC and suggests a common source for present day SIV isolates. 相似文献
3.
A polymorphic system of ADH isozymes is described in the honeybee Apis mellifera. Three and six different electrophoretic patterns were found, respectively, in drone and worker pupae analysis. The data indicate that the ADH isozymes are controlled by three alleles, Adh-1
1, Adh-12, and Adh-1
3. The frequency of the Adh-1 alleles is different in two analyzed subspecies, Apis mellifera adansonii (African bees) and Apis mellifera ligustica (Italian bees). In the African bees, the frequencies are 0.256 and 0.697 for Adh-1
1 and Adh-12, respectively. In the Italian bees, these values are shown to be 0.902 and 0.098, respectively. The allele Adh-1
3 was not detected in the Italian bee population. The effect of NAD on the resolution of this system was investigated, and only one region of ADH activity was obtained in drone pupae analysis when NAD was used in the gels. However, two different regions of activity were observed in the same samples, in the absence of the coenzyme. ADH activity was not detected in young larvae, but it increased to a maximum in prepupal and white-eyed pupal phases. It then declined progressively to total absence in the emerging bees.This work was supported by the Brazilian Research Council (CNPq) and S~ao Paulo State Research Foundation (FAPESP). This study was performed by the senior author in partial fulfillment of the requirements for a master's degree and was directed by Dr. M. A. Mestriner, Genetics Department, University of São Paulo at Ribeirão Preto. 相似文献
4.
Pearl millet (Pennisetum typhoides) produces three ADH isozymes, sets I, II, and III, with set III being expressed only in anaerobically treated seeds or seedlings. Variant strains have been identified which produce ADH isozymes with altered electrophoretic mobilities for sets I and II but not for set III activity. Based on genetic analysis of these variants and on dissociation-reassociation experiments, we propose that the three ADH isozymes are dimers of subunits coded by two structural genes, Adh1 and Adh2, with set I being a homodimer specified by Adh1, set III a homodimer specified by Adh2, and set II a heterodimer formed between the products of Adh1 and Adh2.This work was supported by BRSG Grant RR 07080 awarded by the Biomedical Research Grant Program, Division of Research Grants, National Institutes of Health, to D. R. H., and by funds from the Margenroth Endowment to F. B.-B., who is a PHS Research Service Award Trainee in Genetics. 相似文献
5.
Gower's (1977) method for the canonical analysis of asymmetric matrices (CAA) where the same entities index both the rows and the columns is described. This technique displays the indexing entities in a series of orthogonal planes of decreasing importance in such a way as to preserve the pattern of the asymmetry between them. The analysis is applied to a half-diallel experiment and to some leaf-overtopping data, both from a study of the control of relative abundance of perennials in chalk grassland. The results suggest a common source for the asymmetry in the very different interference and overtopping data, namely that of leaf height. It is concluded that relative abundance in the field may be determined, in part, by leaf height through aboveground interference between plants.Nomenclature follows Tutin et al., 1964–1980. Flora Europaea, Vols 1–5. Cambridge University Press, Cambridge.I am particularly indebted to the Nature Conservancy Council for permission to carry out the field experiment on the Aston Rowant N.N.R., and to do field work at Castle Hill N.N.R.We are grateful to R. A. Kempton for permission to use his methodology in the analysis of the half-diallel experiment prior to publication. This work was carried out while J.M. was in receipt of a Research Studentship from the Natural Environment Research Council, and L.G. was in receipt of an internal Research Studentship from Trinity College, Cambridge. 相似文献
6.
7.
Objective: The disinhibition scale of the Eating Inventory predicts weight loss outcome; however, it may include multiple factors. The purpose of this study was to examine the factor structure of the disinhibition scale and determine how its factors independently relate to long‐term weight loss outcomes. Research Methods and Procedures: Exploratory factor analysis of the disinhibition scale was conducted on 286 participants in a behavioral weight loss trial (TRIM), and confirmatory factor analysis was conducted on 3345 members of the National Weight Control Registry (NWCR), a registry of successful weight loss maintainers. Multivariate regressions were used to examine the relationships between the disinhibition scale factors and weight over time in both samples. Results: Using baseline data from TRIM, two factors were extracted from the disinhibition scale: 1) an “internal” factor that described eating in response to internal cues, such as feelings and thoughts; and 2) an “external” factor that described eating in response to external cues, such as social events. This factor structure was confirmed using confirmatory factor analysis in the NWCR. In TRIM, internal disinhibition significantly predicted weight loss at 6 months (p = 0.03) and marginally significantly predicted weight loss at 18 months (p = 0.06), with higher levels of internal disinhibition at baseline predicting less weight loss; external disinhibition did not predict weight loss at any time‐point. In NWCR, internal disinhibition significantly predicted one‐year weight change (p = 0.001), while external disinhibition did not. Discussion: These results suggest that it is the disinhibition of eating in response to internal cues that is associated with poorer long‐term weight loss outcomes. 相似文献
8.
A climate model with time varying parameters was fit to longleaf pine (Pinus palustris) tree rings collected from the proposed Harrison Research Natural Area of the De Soto National Forest in southern Mississippi. The purpose of the analysis was to determine if any unexpected disturbances had influenced the growth of the trees. Current September temperature, August rainfall and February Palmer Drought Severity Index (PDSI) were found jointly to be the best variables in the model to predict growth. August rain had a constant significant effect on growth and February PDSI was not significant except between the years 1968–1983. It was concluded that the Harrison area has been in equilibrium for the past 50 years since no apparent outside influences have caused the trees to become less sensitive to climate. Thus, the forest is a good candidate for a Research Natural Area.Abbreviations (RNA)
Research Natural Area 相似文献
9.
In previous work (Freedman and Wolkowicz, 1986;Bull. math. Biol.
48, 493–508) it was shown that in a predator-prey system where the prey population exhibits group defence, it is possible that
enrichment of the environment could lead to extinction of the predator population.
In this paper a third population is introduced and criteria are derived under which persistence of all populations will occur.
In particular, criteria for a superpredator and for a competitor to stabilize the system in the sense of persistence are analyzed.
Research partially supported by the Natural Sciences and Engineering Research Council of Canada, Grant No. NSERC A 4823.
This research was carried out while the author was a visiting scholar at the University of Alberta. 相似文献
10.
John G. Scandalios Wu-Fu Tong Demetrios G. Roupakias 《Molecular & general genetics : MGG》1980,179(1):33-41
Summary A new and unique catalase isozyme, CAT-3, has been found in Zea mays. It is encoded in the Cat3 nuclear structural gene which is distinct from the two previously described catalase structural genes, Cat1 and Cat2. The Cat3 gene is both tissue- and time-dependent in its expression, being expressed primarily in young leaves and in the pericarp of nearly mature kernels. Cell fractionation experiments, utilizing epicotyl (coleoptile+primary leaf) and mesocotyl cells, suggest that CAT-3 is associated with the mitochrondria where it may play a role in the alternate oxidase pathway. CAT-3 was purified and characterized with respect to some of its biochemical properties. While CAT-3 differs in some of its properties from CAT-1 and CAT-2, it is similar to these and to other catalases in most respects.Research supported by National Institutes of Health Grant No. GM 22733 to JGS.Paper No. 5255 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC. 相似文献
11.
De-emulsification of oil-in-water emulsions by Bacillus subtilis 总被引:3,自引:0,他引:3
K. L. Janiyani H. J. Purohit R. Shanker P. Khanna 《World journal of microbiology & biotechnology》1994,10(4):452-456
Bacillus subtilis grown on glucose produced a de-emulsifier that broke down model oil-in-water emulsions. The deemulsification increased with contact time and the recovery of oil was 98% with 0.6 mg de-emulsifier/ml emulsion. GLC and i.r. analysis of the molecule extracted from cell-free broth demonstrated that the de-emulsifier was acetoin. It may be better to use acetoin, a metabolite of glucose metabolism, to recover oil from oily sludges instead of microbial cells, because of its stability and de-emulsification activity.The authors are with the Director's Research Division, National Environmental Engineering Research Institute, Nehru Marg, Nagpur 440 020, India 相似文献
12.
A. Capriotti 《Archives of microbiology》1958,30(4):383-386
Summary A new species of Torulopsis is described; it was isolated from some materials used for silage. This species is named Torulopsis wickerhamii nova species in honour of Prof. L. J. Wickerham of Northern Regional Research Laboratory at Peoria-Illinois-U.S.A. 相似文献
13.
On the functional organization of the arg ECBH cluster of genes in Escherichia coli K-12 总被引:11,自引:0,他引:11
R. Cunin D. Elseviers G. Sand G. Freundlich G. Glansdorff 《Molecular & general genetics : MGG》1969,106(1):32-47
Summary Among the four seemingly adjacent loci of the argECBH cluster of E. coli K-12, the last three are shown to belong to the same unit of coordinated expression; the latter exhibits a clockwise polarity in contrast to all other known E. coli operons, except the cluster governing the synthesis of the pyruvate dehydrogenase complex.The analysis of several deletion and nonsense mutants suggests that argE (the expression of which is not strictly correlated with the functioning of the argCBH group) has the same polarity but is not integrated with the three other genes into one operon.Between polar argC B and B mutants the coefficient of repressibility of enzyme H synthesis varies widely. This feature resembles the reduced repressibility of distal gene activity found in polar mutants in the tryptophan operons of E. coli and S. typhimurium but not in the lac, gal (E. coli) and his (S. typhimurium) operons.Possible implications of the present results and some relevant data that have appeared in the recent literature are discussed.Research fellow of the Institute for the Encouragement of Scientific Research in Industry and Agriculture, Belgium.Research fellow of the National Fund of Scientific Research, Belgium. 相似文献
14.
Karyotypes prepared from tissues of gills, gonads, fins, liver, and spleen, yielded the following diploid numbers: all Esox spp. 50, all Umbra spp. (excluding U. krameri) 22, Novumbra hubbsi 48, Dallia pectoralis 78. DNA measurements from Feulgen stain content of erythrocytes, indicated that the species could be divided into two categories: 30–39% of human-Esox spp., Dallia pectoralis, Novumbra hubbsi: 70% of human-Umbra spp. Chromosomal polymorphism was not observed among the various tissues examined nor was it observed among specimens from different habitats. Both the karyotypes and the DNA values indicated that the present tendency to combine the genera Umbra, Novumbra, and Dallia in the single family Umbridae may be ill advised.This work was supported by grants from the Fisheries Research Board of Canada and the National Research Council of Canada. 相似文献
15.
Ekta Chaudhary 《International journal of phytoremediation》2019,21(3):279-286
Phytoremediation potential of Lemna gibba was evaluated for chromium (Cr) and cadmium (Cd) under laboratory conditions for variable metal load of 1?mg/l, 3?mg/l, 5mgl, 7?mg/l and 9?mg/l, respectively, for 7 and 15?days of treatment period. Effects of both metals on structural attributes of L. gibba were also analyzed by Scanning Electron Microscopic (SEM) study. The metal removal percentage by L. gibba for Cr metal was found in the range of 37.3% to 98.6% and for cadmium it was found within the range of 81.6% to 94.6%. Bio concentration factor (BCF) of L .gibba was observed within the range of 37 to 295 for Cr metal and for Cd metal it ranged from 237 to 1144, which shows that the plant is a hyper accumulator for Cd metal and moderate accumulator for Cr metal. Statistical analysis (Two-way ANOVA) was performed on experimental results to confirm the individual effect of metal concentration and treatment period as well as cumulative effect of both factors together on percentage metal removal and on BCF. Research studies indicated that with the progress of treatment period metal removal percentage increases but increasing metal load during experiment negatively co-relates the metal removal percentage and BCF. 相似文献
16.
D. C. Rao P. M. Laskarzewski J. A. Morrison P. Khoury K. Kelly C. J. Glueck 《Human genetics》1982,60(3):257-261
Summary Commingling analysis of plasma uric acid levels in a random sample of 160 nuclear families supports the hypothesis that there is a mixture of three distributions. Assuming one, two, and three components in the underlying distribution, we obtained the corresponding p-values (for power transformation) as 0.059, 1.040, and 1.643, respectively. Path analysis with p=0.059 gives genetic (h
2) and cultural (c
2) heritabilities as 0.256 and 0.199, without much support for intergenerational differences, assortative mating, or maternal effects. Complex segregation analysis with p=0.059 supports multifactorial inheritance, consistent with the findings of Gulbrandsen et al. (1979) and Morton (1979) in other populations. This study also fails to support a major locus hypothesis, contrary to earlier reports.This work was supported in part by N.I.H. and N.I.M.H. Grants GM 28719, and MH 31302, and by contract NO-1-HV-2-2914L from the National Heart, Lung, and blood Institute (Lipid Research Clinic's Program), General Clinical Research Center, and the CLINFO center Grant RR-00068-19 相似文献
17.
Aaron M. Potretzke Kathryn H. Schmitz Michael D. Jensen 《Obesity (Silver Spring, Md.)》2004,12(10):1698-1701
Objective: Computed tomography (CT) is a common research procedure for measuring abdominal fat distribution, but little is written about the software used to analyze images. Our objective was to compare in‐house and commercially available software for quantitative measurement of abdominal fat distribution. In the process, we encountered some unexpected problems. Research Methods and Procedures: A total of 123 volunteers had single‐slice abdominal CT images taken that were used to evaluate various aspects of the commercial image analysis program. Results: The agreement between the commercial and in‐house programs was excellent (r = 0.996, p < 0.00, 001) for both total and intraabdominal fat, and we were able to reduce between‐observer variability in measured fat areas through the use of statistical handling of region of interest information. We also noted that intracolonic contents sometimes had the same Hounsfield units as adipose tissue. We analyzed single‐slice CT images from 50 volunteers to determine the potential impact of this effect on visceral fat area; the overestimate of visceral fat area was 19 ± 22% (maximum, 112% overestimate). The commercial program could prevent this error, whereas our in‐house program could not. Discussion: We concluded that a readily available commercial image analysis program compares well with a previously validated in‐house program and that it offers some advantages with respect to preventing overestimation of pixels as visceral fat. 相似文献
18.
Elke M. Lohmeier-Vogel Bärbel Hahn-Hägerdahl Hans J. Vogel 《Applied microbiology and biotechnology》1986,25(1):43-51
Summary
Streptococcus lactis ferments glucose in a homolactic fashion but a heterolactic fermentation pattern is observed when it is grown on maltose. Using in vivo phosphorus-31 and carbon-13 NMR studies of glucose-metabolizing cells we confirmed that fructosediphosphate (FDP) is the major glycolytic intermediate and that the production of lactate causes major changes both in the intra- and extracellular pH values. Starved cells contain mainly 3-phosphoglycerate (3-PGA) and some phosphoenolpyruvate (PEP). Metabolism of maltose also brings about major changes in pH, but it was unclear from the poorly resolved in vivo spectra if FDP was the main glycolytic intermediate present. This question was further studied by analyzing perchloric acid extracts by phosphorus-31 NMR. These studies showed that glucose-metabolizing cells have higher levels of FDP and lower levels of inorganic phosphate (P
i
) than maltose-metabolizing cells. 3-PGA always remained present in the latter cells suggesting that these exist in a semi-starved state which is probably the reason for their heterolactic fermentation pattern. In the course of these studies we also examined the effects of the inhibitors 2-deoxyglucose, fluoride and iodoacetate. We could demonstrate that by judicious choice of carbon sources and inhibitors one could completely reduce the intracellular P
i
pool. This suggests that one should be able to regulate the shift from heterolactic to homolactic fermentation, as P
i
is considered to be the most potent inhibitor of pyruvate kinase in these cells.Sponsored by grants from the Swedish Natural Sciences Research Council (NFR) (to BHH and HJV), the Biotechnology Research Foundation (SBF) (to BHH) and the Canadian Natural Sciences Research Council (NSERC) (to HJV) 相似文献
19.
《Biotechnic & histochemistry》2013,88(1):18-23
AbstractHigh quality cancer research using human biospecimens must be based on biospecimens that have been obtained according to rigorous ethical and procedural standards. Methods for biospecimen collection, stabilization, processing and storage for research, however, are highly variable and the biospecimens available for research often are of unknown quality. The National Cancer Institute Biospecimen Research Network program was initiated in 2006 to conduct, sponsor, report and collaborate on research to better understand the effects of different biospecimen collection methods on downstream molecular analysis. An online Biospecimen Research Database and an annual symposium, Advancing Cancer Research through Biospecimen Science, have been developed and many research projects are underway to develop a knowledge base from which to develop evidence-based biospecimen standard operating procedures and methods for assessing biospecimen quality. These efforts will enable better cancer research and development efforts. 相似文献
20.
Hubert Denise Jacqueline Poot Maribel Jiménez Audrey Ambit Daland C Herrmann Arno N Vermeulen Graham H Coombs Jeremy C Mottram 《BMC molecular biology》2006,7(1):42-13