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1.
本研究利用同源克隆法以苹果属平邑甜茶和杂种后代叶片为试验材料,克隆得到4个SERK基因家族片段,并分析了SERKs家族基因在平邑甜茶和杂种后代不同器官和组织中的表达情况。研究结果表明:分离获得的4个SERK基因家族片段的氨基酸序列与模式植物拟南芥、烟草等植物的同源性均在84%以上,同时与其他物种的氨基酸序列进行Blast比对都具有较高的同源性;RT-PCR定量分析结果表明SERK1、SERK2、SERK3、SERK4基因主要在生殖器官中表达。因此,推测SERKs基因在平邑甜茶和杂种后代生殖发育过程中起着重要的调控作用。本研究结果为进一步揭示无融合生殖的发生机理奠定了基础。 相似文献
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Antibodies to Coxiella burnetii have been found in the Danish dairy cattle population with high levels of herd and within herd seroprevalences. However, the prevalence of antibodies to C. burnetii in Danish beef cattle remains unknown. The objectives of this study were to (1) estimate the prevalence and (2) identify risk factors associated with C. burnetii seropositivity in Danish beef and dairy cattle based on sampling at slaughter. 相似文献
4.
Developmentally specific expression of Rhizobium spp. genes involved in symbiotic N2 fixation is known to operate through cascade regulation of various nif and fix operons. Fusion constructs of lacZ under symbiotic promoters P1 (for nifHDK operon) and P2 (for fixABCX operon) of Rhizobium meliloti were mobilized into Rhizobium spp. (Cicer) strains Rcd301 and RCR13. The assays for -galactosidase activity to monitor the expression of lacZ under these promoters was performed in host backgrounds of Escherichia coli, R. meliloti, and Rhizobium spp. (Cicer). The enzyme assays indicated significant levels of expression from P1 and P2 promoters in chickpea rhizobia, specifically in symbiotic cells from nodules. However, as in R. meliloti, these promoters did not induce strong expression in free-living cells of Rhizobium spp. (Cicer). This indicates functional homology of R. meliloti promoters in rhizobium spp. (Cicer). Functional cross-reactivity of trans regulatory factors like NtrA, NtrC, and NifA between these rhizobia seems evident from the nodule-specific expression of P1 and P2 cis elements. 相似文献
5.
The aim of this study was to compare three different enzyme-linked immunosorbant assays (recombinant major antigenic protein 2 (rMAP2)-ELISA, the Immunocomb (Biogal, Israel) and the Snap 3Dx assay (IDEXX Laboratories Inc., USA)) with the indirect immunofluorescent antibody test in detecting anti-Ehrlichia canis immunoglobulin-G (IgG) antibodies. Samples tested were collected from dogs suspected to be naturally infected with E. canis and from experimentally infected dogs.When qualitative results (positive/negative) were compared, there was an overall agreement of 81% (54/67) between the indirect immunofluorescence antibody (IFA) test and the rMAP2-ELISA. An overall agreement of 94% (63/67) was found between the IFA test and the Immunocomb, and an overall agreement of 91% (61/67) was found between the IFA test and the Snap 3Dx assay. In 50 of 67 (74.6%) samples tested, complete agreement in the qualitative results was found in all four tests. Sixteen of 17 samples with disagreement in the qualitative results were found to have IFA titers of 1:320 or less. The sensitivities and specificities of the tests were found to be 0.71 and 0.85 for the rMAP2-ELISA, 0.86 and 0.98 for the Immunocomb, and 0.71 and 1.00 for the Snap 3Dx assay.The tests performed in this study were found to be highly specific in detecting E. canis antibodies. Their sensitivity was found to be low with sera having IFA titers of < or =1:320, while high with sera having titers greater than 1:320. Repeating the serological tests 1-2 weeks after the first antibody assay may overcome the sensitivity problem with titers of < or =1:320. 相似文献
6.
Study of genetic diversity in Indian and exotic sesame (Sesamum indicum L.) germplasm using random amplified polymorphic DNA (RAPD) markers 总被引：1，自引：0，他引：1
Fifty-eight accessions of sesame (Sesamum indicum L.), an important oil seed crop of the tropics and subtropics were analysed using random amplified polymorphic DNA (RAPD)
technique. The material analysed comprised 36 collections from 18 different states of India and four adjoining countries of
the Indian subcontinent, and 22 exotic accessions from 21 sesame growing countries around the world. The results from PCR
amplifications with the selected 24 random 10-mer primers were statistically analysed. The value of Jaccard’s similarity coefficients
ranged from 0.19 to 0.89. The results indicated the presence of high level of genetic diversity. However, the extent of genetic
diversity was greater in the collections from Indian subcontinent as compared to the exotics. Among the Indian accessions,
the collections from Rajasthan and North-eastern states were highly diverse. The phenetic analysis grouped 48 out of 58 accessions
in six clusters and the remaining highly diverse accessions were placed outside these close-knit clusters. The Bootstrap estimates
obtained by Wagner parsimony analysis were significant for seven out of 49 nodes in the majority-rule consensus tree (<95%
occurrence). The results of both the analyses were, however, broadly comparable when the constitution of the individual clusters
were considered. The principal components analysis indicated that the first two components accounted for only 21% of the total
variations and in order to explain <75% of variations 18 components were required. The high level of genetic diversity prevalent
among the Indian collections is probably indicative of the nativity of this crop species. Similarly, the relatively lower
level of polymorphism in exotic germplasm could be ascribed to the comparatively recent introductions of limited germplasm
of this crop into some of the non-traditional sesame growing countries.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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8.
A. K. Dang Suman Kapila Maneesh Purohit Charan Singh 《Tropical animal health and production》2009,41(7):1213-1217
Colostrum samples were collected from 8 Murrah buffaloes on days 1, 2, 3, 4 and 5 after calving. Levels of IgG averaged 54.0 mg/ml
at calving, then decreased significantly (P < 0.01). IgA and IgM on day 1 were 3.22 mg/ml and 5.22 mg/ml, respectively; both
decreased during the first five days after calving. Values of IgA and IgM were higher than those reported in cows. SCC values,
which were high at calving (500 000 per ml), reduced significantly (P < 0.01) on day 2, then decreased slightly until day
5 (180 000 per ml). At calving, macrophages were the most prominent cells in buffalo colostrum, followed by lymphocytes and
neutrophils. Phagocytic activity was 23% at calving and reduced significantly (P < 0.01) to 14% on day 5. Phagocytic index
was highest in the first colostrum, and then decreased non-significantly. 相似文献
9.
Intensive cropping and exhaustive nature of sugarcane–wheat–rice cropping system in the Indo-Gangetic Plains of South Asia have led to the depletion of soil organic carbon content and inherent soil fertility resulting in a serious threat to the sustainability of these production systems. Bioagents like Gluconacetobacter diazotrophicus and Trichoderma viride have great potential to restore soil fertility and promote sugarcane growth. Field experiments, therefore, have been conducted to study the integrated effect of bioagents (G. diazotrophicus and T. viride), Farm Yard Manure (FYM) and fertilizer N on sugarcane rhizosphere, crop yield and N economy for two crop cycles during 2004–2006 and 2005–2007 crop seasons at Lucknow, in the middle Indo-Gangetic plain region. Both bioagents could survive and colonize sugarcane rhizosphere and FYM improved their colonization. Enhanced soil microbial population and microbial carbon (SMC) and nitrogen (SMN) with increasing N level were probably due to more available N in the soil. FYM/bioagents amendment further enhanced the microbial carbon. The uniform increase in the fraction of SMC and SMN of total organic carbon indicated that immobilization/mineralization was being maintained in the soil where enhanced microbial biomass might act later as a source of nutrients.Bioagents ammended FYM enhanced the uptake of N, P and K in sugarcane at all the levels of fertilizer N. It was mainly due to the enhanced nutrient availability in the rhizospheric soil as the soil organic C and available N, P and K content increased with the application of bioagents/FYM. A saving of 76.3 kg N ha−1 was envisaged by the use of G. diazotrophicus inoculated FYM with marginal (2.4 t ha−1) decline in the cane yield. Application of T. viride enriched FYM, however, brought economy in the use of fertilizer N by 45.2 kg ha−1 and also increased the yield by 6.1 t ha−1compared to the control treatment. Overall, strategic planning in terms of an integrated application of these bioagents/manures with fertilizer N will not only sustain soil fertility but will also benefit farmers in terms of reducing their dependence and expenditure on chemical fertilizers. 相似文献
10.
Downy mildew (DM) caused by Peronospora arborescens is the most destructive disease of opium poppy which assumes considerable importance in India and other poppy growing countries.
The present study was aimed at identification and evaluation of stable resistance sources of DM in opium poppy. Furthermore,
genetic variability and inheritance pattern of DM resistance has also been studied which can help in making strategy for crop
improvement. Evaluation of 35 selected germplasm accessions of opium poppy under glasshouse and field conditions during the
three consecutive years (2004–2005 to 2006–2007) resulted in identification of two genotypes (I-14 and Pps-1) as highly resistant
and stable sources for DM resistance. Genetic studies of DM resistance revealed polygenic control with the dominance of susceptibility
over resistance. Significant reciprocal differences were found largely due to maternal transmission of DM resistance indicating
the involvement of cytoplasmic genes in addition to nuclear control. Analysis of genetic variability and selection parameters
indicated predominance of additive effects for DM resistance and other yield contributing traits. Multivariate analysis resulted
in classification of 35 selected accessions into 11 different clusters revealing very high level of diversity among the genotypes.
Cluster analysis suggested that hybridization program involving genotypes from cluster V (which included highly resistant
genotypes Pps-1 and I-14) and cluster IX (which included highly susceptible Jawahar-16 having good economically important
traits like seed yield) could be expected to give best recombinants for improvement in terms of DM resistance and high seed
and straw yield in opium poppy. Analysis of selection parameters like heritability and genetic advance also suggested that
simple selection methods will be effective in stabilizing resistance traits following hybridization with high yielding genotypes. 相似文献