不同青枯病抗性的番茄品种内生细菌生理群数量研究

本论文对青枯病抗性不同的番茄品种其内生细菌生理群数量变化进行了研究,结果表明,番茄内生细菌生理群数量的变化随品种抗性、生育期和季节的不同而变化.在7大类生理群细菌中,氨化细菌的数量最多,且在幼苗期以后,高抗青枯病番茄品种中数量明显高于高感品种,初步认为,氨化细菌可能是影响青枯病发生的关键性微生物.番茄抗病品种在不同生育期,其内生细菌的总体数量要比感病品种多,呈交替波动变化.氨化细菌、硝化细菌、固氮细菌和反硫化细菌平均数量均表现为在夏季高于冬季,硫化细菌的数量则冬季高于夏季,厌气性细菌数量最少.     

Does the niche breadth or trade‐off hypothesis explain the abundance–occupancy relationship in avian Haemosporidia?

Two hypotheses have been proposed to explain the abundance–occupancy relationship (AOR) in parasites. The niche breadth hypothesis suggests that host generalists are more abundant and efficient at colonizing different host communities than specialists. The trade‐off hypothesis argues that host specialists achieve high density across their hosts' ranges, whereas generalists incur the high cost of adaptation to diverse immuno‐defence systems. We tested these hypotheses using 386 haemosporidian cytochrome‐b lineages (1894 sequences) recovered from 2318 birds of 103 species sampled in NW Africa, NW Iberia, W Greater Caucasus and Transcaucasia. The number of regions occupied by lineages was associated with their frequency suggesting the presence of AOR in avian Haemosporidia. However, neither hypothesis provided a better explanation for the AOR. Although the host generalist Plasmodium SGS1 was over three times more abundant than other widespread lineages, both host specialists and generalists were successful in colonizing all study regions and achieved high overall prevalence.     

Spatial and temporal habitat use and selection by red deer: The use of direct and indirect methods

Given the importance of red deer Cervus elaphus for hunting and conservation purposes, understanding the interactions between this species and its habitats in the Mediterranean region is a crucial step for the sustainable management of this species. Aiming to compare pellet group counts and direct observations methods to study the habitat use and selection by red deer, the results obtained by both methods were compared, and their advantages and disadvantages were discussed. To understand the temporal patterns of habitat use and selection, the survey was conducted at three different seasons, birth period, rut season and winter. The habitat use and selection were studied in relation to land cover, watercourse, roads, ecotone zones and other topographic features (altitude, slope and aspect), using generalized linear models and selection ratios. The similarity of the results provided by pellet group counts and direct observations indicate that both methods may constitute useful tools to study the habitat use and selection by red deer. Globally, red deer seemed to select habitats that provide simultaneously food and some cover, as shown by its preference for shrublands, independently of the sampling season. The positive selection of ecotone zones embodies the need for open spaces. Males and females showed a similar use of shrubland, but selected patches with different characteristics therein. The spatial and temporal patterns exhibited by our results suggest that red deer balance their habitat requirements in respect to each phase of their reproductive cycle. Pellet group counts and direct observations seem to be useful methods to analyze habitat use and selection, and may provide helpful knowledge to the management and conservation of red deer.     

Effect of zinc supplementation from different sources on growth, nutrient digestibility, blood metabolic profile, and immune response of male guinea pigs

Forty weaned male guinea pigs of 208.20±6.62 g mean body weight were divided into 4 groups of 10 animals in a randomized block design. All of the guinea pigs were fed a basal diet [25% ground maize hay, 30% ground maize grain, 22% ground chickpea (Cicer arietinum L.), 9.5% deoiled rice bran, 6% soybean meal, 6% fish meal, 1.45% mineral supplement (without Zn) and 0.05% ascorbic acid] and available green fodder. Group I served as the control (no Zn supplementation), whereas 20 ppm Zn was added in the diet in groups II, III, and IV either as zinc sulfate (ZnSO₄), zinc amino acid complex (ZAAC), and ZnSO₄ ⁺ ZAAC in equal parts, respectively. Experimental feeding lasted for 70 d, including a 3-d digestibility trial. Blood was collected through cardiac puncture from four animals in each group at d 0 and subsequently at the end of experimental feeding. After 40 d of experimental feeding, four animals from each group were injected with 0.4 mL of Brucella abortus cotton strain-19 vaccine to assess the humoral immune response of the animals. After 10 wk of study, four animals from each group were sacrificed to study the concentration of Zn, Cu, Co, Fe, and Mn in the liver, pancreas and spleen. Results revealed no significant difference in the feed intake, body weight gain, and digestibility of the nutrients, except for crude protein (CP) digestibility, which was significantly (p<0.05) lower in group IV. Although concentrations of serum glucose, Ca, and P and the albumin:globulin (A:G) ratio were similar in the different groups, the total protein, albumin, and serum alkaline phosphatase activity were higher in all of the Zn-supplemented groups on d 70. The serum Zn levels at the end of experimental feeding were significantly higher in groups II and III, whereas serum Mn levels were found to be significantly (p<0.05) higher in groups III and IV. The organ weights (as percentage of body weights) did not show any differences among the treatment groups. Although the Mn concentration was significantly (p<0.05) higher in the pancreas, the Cu concentration was significantly (p<0.05) reduced in the spleen in all of the Zn-supplemented groups. The humoral immune response (antibody titer values) on d 14 of vaccination was significantly (p<0.05) higher in all of the Zn-supplemented groups. It was concluded that the 20-ppm level of Zn in the diet might be adequate for growth and nutrient utilization in guinea pigs, but supplementation of 20-ppm zinc significantly improved the immune response and impact was more prominent with the ZAAC (organic source) compared to ZnSO₄ (inorganic source).     

Identification of intestinal bacteria from Japanese flounder (Paralichthys olivaceus) and their ability to digest chitin

AIMS: The aim of the present study was to clarify the taxonomic status of intestinal bacteria isolated from Japanese flounder (Paralichthys olivaceus) and describe their ability to digest chitin. METHODS AND RESULTS: Phylogenetic analysis based on 16S ribosomal DNA (rDNA) sequences showed that 82 representative isolates were closely related to three major species of marine vibrios, Vibrio scophthalmi-Vibrio ichthyoenteri group (41 isolates), Vibrio fischeri (39 isolates) and Vibrio harveyi (two isolates), with similarities of 97.2-99.8%, 96.4-100% and 98.6-99.5% respectively. These findings indicate that V. scophthalmi-V. ichthyoenteri group is indigenous to the intestinal tract of Japanese flounder. Moreover, the ability of 82 isolates to digest chitin was examined using the agar plate method and PCR amplification of the chiA gene. The two V. harveyi isolates and 36 of 41 V. scophthalmi-V. ichthyoenteri isolates digested chitin and were chiA PCR positive, whereas all 39 V. fischeri isolates digested chitin but were chiA PCR negative. CONCLUSIONS: Intestinal bacteria from Japanese flounder were mainly composed of Vibrio scophthalmi-V. ichthyoenteri group and V. fischeri. Taken together, the results showed that 81 of 82 isolates could digest chitin. However, only 38 of these isolates possessed a chiA homologue which could be identified by PCR. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study shows that Japanese flounder harbours bacteria of the V. scophthalmi-V. ichthyoenteri group, and these results are similar to what has been found for turbot (Scophthalmus maximus).     

Novel selenoorganic compounds as modulators of oxidative stress in blood platelets

Many selenoorganic compounds play an important role in biochemical processes and act as antioxidants, enzyme inhibitors, or drugs. The effects of five new synthesized selenoorganic compounds (2-(5-chloro-2-pyridyl)-7-azabenzisoselenazol-3(2H)-one; 2-phenyl-7-azabenzisoselenazol-3(2H)-one; 2-(pyridyl)-7-azabenzisoselenazol-3(2H)-one; 7-azabenzisoselenazol-3(2H)-one; bis(2-aminophenyl) diselenide) on oxidative changes in human blood platelets and in plasma were studied in vitro and compared with those of ebselen, a well known antioxidant. Our studies demonstrated that bis(2-aminophenyl) diselenide has distinctly protective effects against oxidative stress in blood platelets and in plasma. It might have greater biological relevance and stronger pharmacological effects than ebselen.     

The effect of ambient temperature fluctuations on Culicoides biting midges population dynamics and activity in dairy farms: a longitudinal study

The effect of climatic factors on the presence of Culicoides Latreille (Diptera: Ceratopogonidae) was previously studied. Nevertheless, lack of laboratory rearing data hampers species‐specific prediction of weather fluctuations effect on population size. To determine fluctuations in population size in the field, we recorded Culicoides and other Nematocerans in seven Israeli dairy farms over two‐years (2011–2012) and analysed the association of their dynamics with fluctuations in ambient temperature and total rainfall. In six farms, the most abundant species were Culicoides imicola Kieffer and Culicoides schultzei (Enderlein) gp., primarily composed of parous females, and in one farm Culicoides obsoletus (Meigen) gp., mostly nulliparous females, were dominant. While the total number of insects was similar in both years, Culicoides numbers were significantly higher in 2012, but appeared later in the season and reached a higher peak. A multi‐variable linear regression model demonstrated positive association of C. imicola and C. schultzei numbers with the monthly multi‐annual ambient temperature and its specific deviation, but not with monthly rainfall. C. obsoletus populations peaked at spring and sharply decreased when temperature exceeded 20 °C, and were best modelled by adding quadratic terms. Weather‐specific estimation of population size under field conditions may enable to predict outbreaks intensity of Culicoides‐borne viruses.     

鉴定9个新的RHD基因mRNA可变剪接体

为了研究各种RHD基因mRNA可变剪接体的基因结构, 应用逆转录聚合酶链反应(RT-PCR)检测正常人脐血样本RHD mRNA, 对RHD cDNA进行TA克隆和序列分析, 对各可变剪接体的剪接位点进行DNA序列分析, 并将RHD mRNA进行表达序列标签(ESTs)分析。结果在28个阳性克隆中, 除全长RHD cDNA外, 共检测到12种(包括9种新的)RHD可变剪接体, 发现外显子遗漏、5′和3′剪接位点变异3种剪接形式, 涉及外显子2~9, 其中6种新的剪接体同时存在RHD和RHCE基因同源杂交现象。ESTs分析还检索到内含子保留形式的剪接体。研究表明, RHD基因mRNA存在复杂的可变剪接机制, 除已报道的剪接体外, 检测到9种新的RHD可变剪接体, 并发现了可变剪接和同源杂交并存现象。     

两种动物血巧克力平板分离流感嗜血杆菌效果评价

目的比较羊血、马血巧克力平板痰培养流感嗜血杆菌的检出率和生长情况。方法将送检的痰标本及流感嗜血杆菌标准菌株ATCC10211分别接种于羊血、马血巧克力平板上,置烛缸中,36气培养24h,比较流感嗜血杆菌检出率及其生长情况。结果（1）2种巧克力平板痰培养流感嗜血杆菌的检出率分别为8％、34．5％。（2）标准菌株ATCC10211在马血巧克力平板上生长良好,菌落直径0．5-1．0mm,而在羊血巧克力平板上生长差,菌落大小如“沙粒”,肉眼难见。结论痰培养流感嗜血杆菌使用马血巧克力平板效果优于羊血巧克力平板。