《中国学术期刊影响因子年报》系列数据库首发式的北京召开沙雅县胡杨林土壤可培养细菌的多样性分析

[目的]了解新疆沙雅县胡杨林土壤可培养细菌的多样性.[方法]沙雅县胡杨林采集土壤样品,采用两种不同的培养基(LB,TSA)分离纯化细菌,并对它们进行16S rDNA测定和系统进化分析.[结果]分离纯化不同表型的57株细菌.对它们16S rDNA序列分析表明,57株菌分别属于3个大类群厚壁菌门(Firmicutes),放线菌门(Actinobacteria),γ-变形菌纲(γ-Proteobacteria),13个属,33个种;芽孢杆菌属是优势细菌种群,它占已测种群的67.2;.其中6株菌M28,M13,CT3,YS30-1,CM5,CL19初步被认为是潜在的新种(16S rDNA相似率为96.780;～97.961;).[结论]沙雅县胡杨林可培养细菌不仅具有比较高的多样性,并存在一些潜在的新的细菌菌种资源,极具进一步发掘的潜力.     

新疆库米什金矿土壤可培养细菌的多样性分析

[目的]了解新疆库米什一处金矿土壤可培养细菌的多样性及建立菌种资源库.[方法]采集库米什金矿土壤样品,采用两种不同培养基(LB,TSB)分离纯化细菌,对其进行形态观察(菌落及细胞)、生理测定、16SrDNA测序和系统进化分析.[结果]从两种培养基上总共得到50株细菌,根据基于16S rDNA的系统进化分析表明,50株菌分别属于3个大类群:厚壁菌门(Firmicutes ),放线菌门(Actinobacteria),γ-变形菌纲(γ-Proteobaeteria),12个属,30个分类单元.其中芽抱杆菌属(Bacillus)为优势细菌种群,占已测种群的63.3;.菌株L10-5与Bacillus foraminis (AJ717382)有96.463;的相似率,可能为潜在新种.[结论]库米什金矿土壤可培养细菌具有较高的多样性,存在潜在新菌种资源,值得进一步研究.     

MHC class II expression by mast cells in the genital tract of cows

This work examined the presence of MHC class II molecules expressing mast cells in oviduct, uterus and vaginal tissues in cows. The tissue samples of five cows were collected from a local slaughterhouse. Toluidine blue pH 0.5 (TB) and avidin-biotin peroxidase complex (ABC) staining procedures applied to adjacent sections from tissue samples. It was determined that some TB + cells were also gave positive reaction with strept ABC staining for MHC II molecules. To our knowledge this is the first evidence indicating the presence of MHC class II molecules expressing mast cells in the cow.     

Impact of Africa Regional Food Security Program on Nigerian Farmers： The Case of National Special Program for Food Security

This paper examined the impact of National Special Program for Food Security （NSPFS） on the beneficiaries through a qualitative measurement of the food security status of the beneficiaries. A food insecurity index was estimated to measure the well-being of the beneficiaries as affected by the impact of the program. Beneficiaries were classified into four categories： food secure （41%）, food insecure without hunger （46%）, food insecure with moderate hunger （11%）, and food insecure with severe hunger （2%）. Perceptions of beneficiaries were measured. In conclusion, the program has had a positive impact and enhanced food security among the Nigerian beneficiaries. It is not without its short comings which include delayed and untimely disbursement of funds and lack of output markets, irrigation facilities, production inputs and adequate training on technology know-how. The default rate and number of debtors remain high among beneficiaries. Efforts should be made to correct the short comings to improve the effectiveness of the program and justify the huge financial resources that have been committed.     

A Promising Potential of Brown Algae Sargassum polycystum as Irreversible Hydrocolloid Impression Material

This study aimed to investigate the potential use of brown algae Sargassum polycystum as irreversible hydrocolloid (alginate) impression material. Potassium alginate extracted from Sargassum polycystum was prepared in three different compositions (14%, 15%, and 16%) and mixed with other standard components to form an alginate impression material. Prior to that, the purity of potassium alginate was quantified with Fourier Transform Infrared Spectroscopy (FTIR) analysis. As a control material, the alginate impression material from a commercially available product was used. All alginate impression materials were then applied to a die stone model. Dimensional accuracy was measured by calculating the mesiodistal width of incisors in the generated dental cast using a digital caliper 0.01 accuracy (five replications). In addition, to evaluate the dimensional stability, the impression results were poured at four different periods (immediately, 5 min, 10 min, and 15 min). An independent t-test was performed to compare the measurement results with p < 0.05 considered significant. Analytical results confirm that the impression material containing 15% potassium alginate gives the best dimensional accuracy similar to control (p > 0.05). Meanwhile, the optimal dimensional stability was produced in the impression material containing 16% potassium alginate. Our study suggested that brown algae Sargassum polycystum has a promising potential to be used as an alginate impression material in clinical application.     

Profitability and downside risk implications of site-specific nitrogen management with respect to wheat grain quality

Precision Agriculture - Profitability analyses of site-specific nitrogen (N) management strategies have often failed to provide satisfying reasons for adoption of precision farming technologies....     

Prevalence of white spot syndrome virus infection detected by one-step and nested PCR in selected tiger shrimp (<Emphasis Type="Italic">Penaeus monodon</Emphasis>) hatcheries

White spot syndrome (WSS) is considered as a great threat to commercial farming of the tiger shrimp (Penaeus monodon). The causal agent of WSS is a DNA virus called white spot syndrome virus (WSSV). The prevalence of this dreadful virus infection has been studied in five randomly selected hatcheries located in the Cox’s Bazar district of Bangladesh. Both one-step and nested polymerase chain reaction (PCR) involving two pairs of primers, namely, 146F1/146R1 and 146F2/146R2, amplifying the 1447 bp and 941 bp fragments, respectively, were conducted to detect the WSSV. Out of 60 randomly collected shrimps, 12 (20%) were found to be positive by one-step PCR, while 18 (30%) were found to be positive by nested PCR. The nested PCR was found to be much more sensitive than the one-step PCR. The shrimp specimens showing clinical signs of WSS were positive for WSSV by both one-step and nested PCR. Some of the apparently healthy samples were also found to be positive for WSSV by nested PCR. Among the two primer-pairs, the inner pair amplifying the 941 bp fragment was more sensitive than the outer primer pair amplifying the 1447 bp fragment when used in one-step PCR.     

Molecular characterization of the wild relatives of safflower (Carthamus tinctorius L.) in Turkey as revealed by ISSRs

In the present study, we used 39 plant samples representing six Carthamus taxa collected from different regions of Turkey: 11 of C. dentatus, 5 of C. glaucus, 18 of C. lanatus, 3 of C. persicus, 1 of C. tenuis subsp. tenuis and 1 of C. tenuis subsp. gracillimus. On these samples, we screened nine ISSR markers for polymorphic products. We generated 151 polymorphic bands. In a dendrogram based on these ISSR bands, the first branch was C. tenuis subsp. gracillimus, then C. persicus formed the second group. The rest of the taxa were grouped in two clusters: the first included C. lanatus, C. tenuis subsp. tenuis and C. glaucus, and the second included C. dentatus. Within the first cluster, C. tenuis subsp. tenuis and C. glaucus grouped together and then united to C. lanatus. Representatives of the same taxa consistently clustered together. Also within species, the groupings were generally concordant with their geographical distributions.     

Assessment of genetic diversity among wheat (Triticum aestivum L.) cultivars from a range of localities across Pakistan using random amplified polymorphic DNA (RAPD) analysis

Genetic diversity among 20 wheat genotypes/cultivars from diverse locations of Pakistan was studied using random amplified polymorphic DNA (RAPD) analysis. A total of 445 DNA fragments were amplified with50 random decamer primers 64.38% of which were polymorphic. Genetic similarity matrix based on Nei & Li's (1979) index detected coefficients ranging from 75.60% to 92.74%. These coefficients were used to construct a dendrogram using unweighted pair group of arithmetic means (UPGMA). The wheat genotypes were clustered into one major group (A) and two small groups (B and C). The most distant genotype in the dendrogram was PARC-1 that was 75.60% to 84.94% genetically similar with the other genotypes and clustered with PARC-3 which formed a group distantly related with the other clusters. Moreover, most of the wheat genotypes developed from the same breeding centre clustered in one group. It has been clearly shown that most of the cultivars except PARC-1possessed narrow genetic background. The information would be helpful for future genome mapping programs as well as for the application of intellectual breeder rights in the country. The study will also work as indicator for wheat breeders to evolve varieties with diverse genetic background to achieve sustainability in wheat production in the country. This revised version was published online in August 2006 with corrections to the Cover Date.