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1.
Occurrence of Bacillus subtilis with High Heat Resistance 总被引:4,自引:3,他引:1
2.
Background
Schistosomiasis japonica is prevalent in Asian countries and it remains a major public health problem in China. The major endemic foci are the marsh and lake regions of southern China, particularly the Dongting Lake region bordering Hunan and Hubei provinces, and the Poyang Lake region in Jiangxi province. Domestic ruminants, especially bovines, have long been considered to play a major role in the transmission of Schistosoma japonicum to humans.Methods and Findings
A miracidial hatching technique was used to investigate the prevalence of S. japonicum infections in domestic ruminants and field feces collected from two towns located to the south and east of Dongting Lake, Hunan province, between 2005 and 2010. The overall prevalence of infection was not significantly reduced from 4.93% in 2005 to 3.64% in 2008, after which it was maintained at this level. Bovines comprised 23.5–58.2% of the total infected ruminants, while goats comprised 41.8–76.5%. Infection rates in cattle and goats were significantly higher than those found in buffalo in most study years. The prevalence in buffalo younger than three years was significantly higher than that in those aged over three years. All the positive field samples of feces were derived from bovines in Nandashan. In Matang Town, 61.22% of the positive field feces were from bovines, while the rest were from goats. The positive rates for field feces were approximately the same in April and November/October.Conclusions
The present study found that bovines and goats are major sources of S. japonicum infection in the Dongting lake region and there was age-related resistance in buffalo. Both bovines and goats should be treated equally when controlling S. japonicum infections in the Dongting lake region. It is essential to conduct an additional mass treatment in late March or early April, in addition to the original treatment scheme. 相似文献3.
Purification and characterization of Dolichos lablab lectin 总被引:1,自引:0,他引:1
The mannose/glucose-binding Dolichos lablab lectin (designated DLL) has
been purified from seeds of Dolichos lablab (hyacinth bean) to
electrophoretic homogeneity by affinity chromatography on an ovalbumin-
Sepharose 4B column. The purified lectin gave a single symmetric protein
peak with an apparent molecular mass of 67 kDa on gel filtration
chromatography, and five bands ranging from 10 kDa to 22 kDa upon SDS-PAGE.
N-Terminal sequence analysis of these bands revealed subunit heterogeneity
due to posttranslational proteolytic truncation at different sites mostly
at the carboxyl terminus. The carbohydrate binding properties of the
purified lectin were investigated by three different approaches:
hemagglutination inhibition assay, quantitative precipitation inhibition
assay, and ELISA. On the basis of these studies, it is concluded that the
Dolichos lablab lectin has neither an extended carbohydrate combining site,
nor a hydrophobic binding site adjacent to it. The carbohydrate combining
site of DLL appears to most effectively accommodate a nonreducing terminal
alpha-d-mannosyl unit, and to be complementary to the C-3, C-4, and C-6
equatorial hydroxyl groups of alpha-d-mannopyranosyl and
alpha-d-glucopyranosyl residues. DLL strongly precipitates murine IgM but
not IgG, and the recent finding that this lectin interacts specifically
with NIH 3T3 fibroblasts transfected with the Flt3 tyrosine kinase receptor
and preserves human cord blood stem cells and progenitors in a quiescent
state for prolonged periods in culture, make this lectin a valuable tool in
biomedical research.
相似文献
4.
不同胁迫预处理提高水稻幼苗抗寒性期间蛋白质的变化 总被引:13,自引:0,他引:13
水稻(Oryza sativa L.)幼苗经盐、热激和冷三种不同胁迫预处理均提高了幼苗的抗寒性。与未预处理苗相比,在处理后、低温伤害后和常温下恢复2d的三个时期,不同胁迫预处理苗的可溶性和热不稳定蛋白含量变化趋势甚为相似,但热稳定蛋白含量变化则各有异同。SDS-PAGE图谱分析显示,不同胁迫预处理提高水稻幼苗抗寒性时,其可溶性蛋白、热稳定和热不稳定蛋白组成变化亦各有异同。除诱导出共有的新多肽外,还各自诱导出特有的新多肽。结果表明,植物对不同胁迫的交叉适应存在一定的共同机理,但亦可看出植物对同一种环境胁迫似乎不是以同一的机理去适应。 相似文献
5.
6.
In order to evaluate the impact of the lesser weever on the ecosystem of the southern North Sea, geographical distribution, density, growth, production and food requirements have been estimated. High densities were found on and around the Brown Ridge, an area with high tidal current velocities, medium grain-size of the sediment and a poor benthic fauna. Growth is restricted to the months of June October. During the winter cessation of growth a considerable loss of weight (about 20%) takes place. Mortality has been estimated by using the average size frequency distribution of all catches made from 1972 to 1984. The resulting convex type of survival curve indicates a high survival rate of the II to IV-group fishes. The production (estimated with Allen's graphical method) of a population of 100 individuals including all age groups (0-VI) amounts to 123.7 g AFDW-year'. In areas with highest densities, consequently, production amounts to 0.018–0.078 g AFDW-m2 -year-1 . With an assumed transfer efficiency of 10% through the year, food requirements amounts to 0.18–0.78 g AFDW-m 2 -year -1 . Since the lesser weever feeds mainly on fish (85.6%), almost exclusively on gobies (Pomatoschistus sp.), and with an assumed transfer efficiency of approximately 10%, the indirect predatory pressure exerted by it may amount to 1.6 6.7g AFDW-m 2 .year -1 . A possible feeding by gobies on pelagic organisms (calanoids, mysids) is discussed. 相似文献
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8.
De novo genome sequencing and comparative genomics of date palm (Phoenix dactylifera) 总被引:1,自引:0,他引:1
Al-Dous EK George B Al-Mahmoud ME Al-Jaber MY Wang H Salameh YM Al-Azwani EK Chaluvadi S Pontaroli AC DeBarry J Arondel V Ohlrogge J Saie IJ Suliman-Elmeer KM Bennetzen JL Kruegger RR Malek JA 《Nature biotechnology》2011,29(6):521-527
Date palm is one of the most economically important woody crops cultivated in the Middle East and North Africa and is a good candidate for improving agricultural yields in arid environments. Nonetheless, long generation times (5-8 years) and dioecy (separate male and female trees) have complicated its cultivation and genetic analysis. To address these issues, we assembled a draft genome for a Khalas variety female date palm, the first publicly available resource of its type for a member of the order Arecales. The ~380 Mb sequence, spanning mainly gene-rich regions, includes >25,000 gene models and is predicted to cover ~90% of genes and ~60% of the genome. Sequencing of eight other cultivars, including females of the Deglet Noor and Medjool varieties and their backcrossed males, identified >3.5 million polymorphic sites, including >10,000 genic copy number variations. A small subset of these polymorphisms can distinguish multiple varieties. We identified a region of the genome linked to gender and found evidence that date palm employs an XY system of gender inheritance. 相似文献
9.
Hexose-6-phosphate dehydrogenase (H6PDH-A2; beta-D-glucose:NAD(P)+
oxido-reductase; E.C. 1.1.1.47) of the teleost Fundulus heteroclitus (L.)
shows clinal allelic variation along the east coast of North America. Three
of the major allelic isozymes have been purified and compared for native
molecular weight, subunit molecular weight, isoelectric point, thermal
stability, and steady-state kinetic properties (pH 8.0 and 25 degrees C).
Significant differences were found among the allelic isozymes for
isoelectric point, thermal stability, and some kinetic parameters. The
predominant allelic isozyme in northern populations (H6PDH-AcAc) was found
to be more sensitive to heat denaturation than were the predominant
homozygous allelic isozymes isolated from southern populations (H6PDH-AaAa
and H6PDH-AbAb). The H6PDH-AcAc allelic isozyme had both a significantly
greater Km for glucose-6-phosphate than did either of the southern
phenotypes and a significantly greater Km for NADP+ and Ki of NAD+ than did
one of the southern phenotypes (H6PDH-AaAa). While the allelic isozymes are
functionally nonequivalent, it is not yet known whether these differences
are reflected at higher levels of biological organization.
相似文献
10.
A statistical analysis of the nucleotide sequence variability in 14
published hepatitis B virus (HBV) genomes was carried out using parametric
and nonparametric methods. A parametric statistical model revealed that the
different regions of the genome differed significantly in their
variability. The conclusion was supported by a nonparametric kernel-density
model of the HBV genome. Genes S, C, and P, region X, the precore region,
and the pre-S2/pre-S1 regions were ranked in order of increasing
variability. In many instances, conserved regions of the genome identified
with sequences of known function in HBV biology. However, other
characterized regions (such as pre-S) showed much variability despite the
involvement of their encoded peptides in specific functions. Point
mutations that may result in the formation of stop codons and amino acid
changes may affect the clinical picture of HBV infection and may be
reflected in atypical serological patterns.
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