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1.
Genetics of resistance to soybean cyst nematode (SCN), Heterodera glycines Ichinohe is very complex. Crosses involving PI 437654, which is resistant to all races of cyst nematodes with other sources of resistance (Peking, PI 88788, and PI 90763) indicated that resistance to race 3 was controlled by four genes, two of which were dominant resistance genes and the other two were recessive resistance genes. For race 5, a four gene model with two recessive and two dominant resistance genes in epistasis has been proposed. For race 14, the results suggested a three gene model with one dominant and two recessive alleles. Several other plant introductions have been isolated which have different genes conditioning resistance. Most of the currently grown soybean varieties derived resistance from Peking and/or PI 88788. Resistance to SCN in these soybean varieties has broken down because of the emergence of several new races and populations of SCN. The use of PI 437654 or Hartwig and other plant introductions with different genes for resistance will broaden genetic diversity and stabilize yield.  相似文献   
2.
In a field experiment with four moisture regimes and eight nitrogen levels, the ratios between evapotranspiration and pan evaporation (EtEo) were low in the initial stages of crop growth and attained maximum values at 70–80% (20 and 40% available soil moisture depletion (ASMD)), 65% (60% ASMD) and 55% (80% ASMD) of the crop growth stage. Amongst nitrogen levels, the evapotranspiration ratio (ETR) was highest (3573) under no nitrogen and lowest (1312) with 180 kg N/ha. The 20% ASMD regime utilised less water (ETR= 1499 to produce a kilogram of grain than did the other moisture regimes. The lowest evapotranspiration ratio (914) was recorded with 20% ASMD and 180 kg N/ha in combination. The highest ETR (3954) was found with 60% ASMD and no nitrogen. An additive effect of nitrogen and moisture was found, in indicating that they can be substituted one for the other, when one of them becomes a constraint.  相似文献   
3.
Veterinary Research Communications - Avian pathogenic Escherichia coli (APEC) is responsible for colibacillosis in poultry. APEC remains a constant problem for the poultry industry, despite the use...  相似文献   
4.
The protective bioactivity of punicalagin, a high molecular weight polyphenol isolated from pomegranate fruit pith and carpellary membrane, against oxidative damages to lipids, amino acids constituting the proteins, and guanosine as a model for DNA has been investigated. The ABTS*-, guanosine, and tryptophan radical generated pulse radiolytically were repaired by punicalagin, k = (0.9-15) x 10(7) dm3 mol-1 s-1. The results are rationalized on the basis of the scavenging activity of punicalagin against various one-electron oxidizing radicals, namely, .OH, N3., and NO2. . The formation of the transient species in these reactions and the rate constants of the scavenging reactions have been probed using a time-resolved kinetic spectrophotometric technique. The antioxidant action of punicalagin is expressed not only through its scavenging reactions but also by its ability to form metal chelates. Binding of punicalagin with bovine serum albumin and metal ions such as iron and copper revealed different binding affinities, whereas its binding with DNA was very weak and nonspecific. In vitro cytotoxic studies against three cell lines, namely, Vero (normal African green monkey kidney cell line), Hep-2 (human larynx epithelial cancer cell line), and A-549 (human small cell lung carcinoma cell line) showed that this polyphenol is toxic only at higher concentration.  相似文献   
5.
Pressure-assisted thermal processing (PATP) is being widely investigated for processing low acid foods. However, its microbial safety has not been well established and the mechanism of inactivation of pathogens and spores is not well understood. Fourier transform infrared (FT-IR) spectroscopy was used to study some of the biochemical changes in bacterial spores occurring during PATP and thermal processing (TP). Spore suspensions (approximately 10(9) CFU/mL of water) of Clostridium tyrobutyricum, Bacillus sphaericus, and three strains of Bacillus amyloliquefaciens were treated by PATP (121 degrees C and 700 MPa) for 0, 10, 20, and 30 s and TP (121 degrees C) for 0, 10, 20, and 30 s. Treated and untreated spore suspensions were analyzed using FT-IR in the mid-infrared region (4000-800 cm(-1)). Multivariate classification models based on soft independent modeling of class analogy (SIMCA) were developed using second derivative-transformed spectra. The spores could be differentiated up to the strain level due to differences in their biochemical composition, especially dipicolinic acid (DPA) and secondary structure of proteins. During PATP changes in alpha-helix and beta-sheets of secondary protein were evident in the spectral regions 1655 and 1626 cm(-1), respectively. Infrared absorption bands from DPA (1281, 1378, 1440, and 1568 cm(-1)) decreased significantly during the initial stages of PATP, indicating release of DPA. During TP changes were evident in the bands associated with secondary proteins. DPA bands showed little or no change during TP. A correlation was found between the spore's Ca-DPA content and its resistance to PATP. FT-IR spectroscopy could classify different strains of bacterial spores and determine some of the changes occurring during spore inactivation by PATP and TP. Furthermore, this technique shows great promise for rapid screening PATP-resistant bacterial spores.  相似文献   
6.
Summary A preliminary evaluation for resistance to chili thrips, Scirtothrips dorsalis Hood of 41 and 194 pepper (Capsicum annuum L.) germplasms during 1987 and 1988, respectively, indicated chili accessions may be a promising source of resistance. In contrast, all sweet pepper accessions tested were highly susceptible. A number of chili accessions produced a moderate yield, in spite of a high thrips infestation indicating tolerance to S. dorsalis. Rating for thrips damage was more reliable and efficient than estimating thrips numbers in screening pepper accessions for resistance to thrips. Highly significant, positive correlation between ratings at the seedling stage and final rating for thrips damage indicated the feasibility of screening pepper accessions at the seedling stage. Comparing the similarities in rating among accessions resulted in 40 distinct groups. The variance-covariance matrix of the data from these 40 groups was subjected to principal component analysis. This accounted for 56 and 18 per cent of the variation across the two principal axes, respectively. Projection of chili and sweet pepper accessions along these two axes revealed three distinct clusters. About 80 per cent of chili accessions formed the first cluster, 58 per cent of the sweet pepper accessions formed the second cluster and a third cluster exhibited intermediate ratings for thrips damage. The significance of these findings in relation to geographical divergence and resistance to thrips among pepper accessions is discussed.  相似文献   
7.
8.
The residues of four synthetic pyrethroids from two spray concentrations per compound on sweet orange fruits dissipated at the respective half-life values of 2.45 and 3.15 days for 0.015 and 0.02% fenvalerate; 2.28 and 2.58 days for 0.015 and 0.02% permethrin; 1.73 and 2.12 days for 0.0075 and 0.01% cyper-methrin ; and 2.6 and 2.9 days for 0.0015 and 0.002% deltamethrin, respectively. However, the comparative persistence of synthetic pyrethroids on the rind of sweet orange fruits in the tropical belt in India was found to be in the order of fenvalerate = permethrin > cypermethrin > deltamethrin. No residues were detected in the fruit pulp.  相似文献   
9.
A visual health assessment and survey questionnaire was conducted on 81 Asian elephants (Elephas maximus) housed in 10 animal facilities throughout India between November 2004 and February 2005. The survey questionnaire consisted of 10 questions that evaluated the health of the elephants, and they were completed after visually assessing each individual elephant. The information collected was ranked on a scale that was used to statistically compare the health among the study subjects. This study documented that 43.21% of the captive elephants surveyed exhibited hyperkeratosis. A significant proportion of the elephants owned by tourist camps had poor skin condition when compared with elephants from zoos and at a forest camp. Similarly, captive-born individuals were found to have better skin condition than animals that were caught from the wild. Sixty (74.1%) of the captive elephants that were observed during this study had fissures in their footpads, 20% of which were severe. The prevalence of foot fissures was significantly higher in females. A greater proportion of elephants owned by tourist camps displayed vertical and horizontal toenail cracks in comparison with the forest camp and zoo elephants. It was noted that 76.9% of the wounded animals and 80% of those having abscesses were housed at temples and tourist camps. Also, approximately 8.5% of the captive elephant population observed during this study had eye-related problems, and they were all housed at temples and tourist camps. In conclusion, it was evident that elephants housed at temples or tourist camps exhibited poor skin condition with wounds and abscesses. These findings suggest that the overall condition of the elephants housed at tourist camps was poor compared with elephants housed at zoos and at the forest camp.  相似文献   
10.
Interferon gamma (IFN-γ) or type II interferon is a cytokine that is critical for innate and adaptive immunity against viral and some bacterial and protozoal infections. The importance of IFN-γ in the immune system lies in its ability to inhibit viral replication directly and most importantly from its immunomodulatory effects. Previously, we successfully co-administered IFN-γ along with GAPDH gene of Edwardsiella tarda as bicistronic DNA vaccine in Labeo rohita. In order to ascertain the individual role of IFN-γ, the present study involves cloning and expression of 552-bp IFN-γ open-reading frame (ORF) of L. rohita in striped snakehead (SSN-1) cell line using eukaryotic expression vector system (pQE-TriSystem) followed by transfection in peripheral blood lymphocytes (PBMCs) to evaluate its immunomodulatory ability in comparison to polyinosinic-polycytidylic acid (Poly I:C)-treated PBMCs. The 18.7-kDa protein, expressed in the pQE-IFNγ-transfected SSN-1 cells, reacted with anti-His antibody in Western blot confirming it to be recombinant IFN-γ, whereas the relative expression of IFN-γ, iNOS, Mx, and IL-1β genes in PBMCs was quantified at 24 h and 48 h post treatment by qPCR. The comparative kinetics of all four genes showed significantly (p?<?0.05) high upregulation pattern in both pQE-IFNγ-transfected cell group and Poly I:C-treated cell group demonstrating recombinant IFN-γ as an equally efficient inducer like Poly I:C. Thus, our in vitro experiment results highlight the immunomodulatory potential of recombinant IFN-γ as an analogue to synthetic Poly I:C which warranted future studies to further explore the potential of recombinant IFN-γ as an effective vaccine adjuvant against different microbial invasion.  相似文献   
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