锡林郭勒典型草原植被动态与植被恢复

本文以锡林郭勒盟1999至2004年MODIS和TM影象数据和地面样点数据为依据,从宏观和微观两方面揭示了锡林郭勒草地植被动态规律和变化趋势,并系统分析了草地植被发生的变化原因、驱动因素和机理,阐明了锡林郭勒盟典型草地植被所面临的问题以及应采取的对策和措施。     

切除结膜结合淋巴组织鸡对新城疫疫苗的免疫反应Ⅰ.局部与循环抗体检测

实验将 60只 1日龄健康雏鸡随机分为A、B、C 3组。A组为CALT缺失组 ,B组为免疫组 ,C组为非免疫对照组。A组于 1日龄手术切除下眼睑结膜 ,A、B两组于 1 2日龄结扎鼻泪管后进行点眼免疫接种新城疫克隆 30疫苗。2 3日龄时 ,收集A、B、C各实验组鸡的血清和泪液 ,做红细胞凝集抑制试验 (HI试验 )、酶联免疫吸附试验(ELISA)。比较观察各实验组雏鸡血清和泪液抗体HI效价与IgA、IgG、IgM含量的变化特点。结果 ,1日龄手术切除下眼睑结膜后造成鸡CALT缺失 ,CALT缺失鸡点眼免疫后 ,泪液抗体HI效价与IgA、IgG、IgM含量比免疫组雏鸡低。但对雏鸡的抗体生成的规律并不产影响。故实验证实了CALT对眼区局部抗体的产生及其种类有重要的调控作用 ,协同哈氏腺完成局部免疫的功能     

高寒草甸地区牧草生长量模拟模式研究

本文讨论了土壤含水量和蒸散量对牧草生长量的影响过程，提出牧草干物质增长模式。并根据青海海北高寒草甸地区的气象条件，对牧草生长模式进行数值模拟，同时，与实测值进行比较，模拟结果与实测值趋向一致，可为牧草产草量预报提供一定实用价值和科学依据。     

Ultraviolet imaging spectroscopy shows an active saturnian system

Neutral oxygen in the saturnian system shows variability, and the total number of oxygen atoms peaks at 4 x 10(34). Saturn's aurora brightens in response to solar-wind forcing, and the auroral spectrum resembles Jupiter's. Phoebe's surface shows variable water-ice content, and the data indicate it originated in the outer solar system. Saturn's rings also show variable water abundance, with the purest ice in the outermost A ring. This radial variation is consistent with initially pure water ice bombarded by meteors, but smaller radial structures may indicate collisional transport and recent renewal events in the past 10(7) to 10(8) years.     

Development of ITS sequence based SCAR markers for discrimination of Paphiopedilum armeniacum, Paphiopedilum micranthum, Paphiopedilum delenatii and their hybrids

Paphiopedilum armeniacum, Paphiopedilum micranthum and Paphiopedilum delenatii are endangered orchid species. These three Paphiopedilum species and their hybrids are difficult to distinguish morphologically. In this study, rDNA-ITS (internal transcribed spacer) sequences were used to design species-specific SCAR (sequence characterized amplified regions) markers to distinguish P. armeniacum, P. micranthum, P. delenatii and their respective hybrids. The developed markers efficiently amplified 600 bp DNA product for P. armeniacum and its hybrids (SCAR-600armF/Pap-ITS2R), 300 bp product for P. delenatii and its hybrids (SCAR-300delF/Pap-ITS2R) and 700 bp product for P. micranthum and its hybrids (SCAR-700micF/Pap-ITS2R). The effectiveness of designed species-specific markers was also confirmed by using multiplex polymerase chain reaction amplification with a combination of developed three SCAR markers.     

浅析野燕麦草对洛隆县主要农作物的危害及防治措施

野燕麦（Avena fatual）西藏群众俗称“跃布”，在西藏分布很广。是西藏高原农区最主要的一种杂草。由于其在西藏高原适应性强，繁殖极快，已成为一种难以除尽的团间恶性杂草．在海拨2400-4500米农区普遍存在。我地区以洛隆、边坝两县为野燕麦高发区。     

Antimicrobial susceptibility and plasmid analysis of Actinobacillus pleuropneumoniae isolated in Taiwan.

Sixty Actinobacillus pleuropneumoniae (App) strains from pigs in Taiwan were examined. Serotyping revealed that these belonged to serovars 1 (n=53), 2 (n=3), and 5 (n=4). Agar disk diffusion susceptibility testing of the isolates showed 55 (92%) were resistant to three or more antimicrobial agents. Six resistance patterns were observed. Ampicillin-chloramphenicol-flumequine-nalidixic acid-streptomycin-sulfonamide/trimethoprim-tetracycline was the most common multi-resistance pattern. Minimal inhibitory concentration of 14 antimicrobial agents was determined. The isolates were highly susceptible to ceftiofur and trimethoprim in vitro. Isolates were resistant to streptomycin, ampicillin, and nalidixic acid. All isolates were examined for the presence of plasmids using the alkaline lysis method. Forty three (72%) isolates had four plasmid bands with an approximate sizes of 3.5, 4.3, 5.8 and 6.0 kb; 12 (20%) had three bands at 3.5, 4.3 and 5.2 kb, and 5 (8%) had no plasmid bands. Antimicrobial resistance plasmids were detected in resistant strains of App. Three antimicrobial resistance plasmids were transformed into E. coli DH5 alpha. pTMY1 (4.3 kb) encoded a streptomycin kinase and a dihydropteroate synthase; pTMY2 (6.0 kb) encoded ROB-1 beta-lactamase and aminoglycoside 3'-phosphotransferase; pTMY3 (5.2 kb) encoded only ROB-1 beta-lactamase. The 4.3 kb plasmid was sequenced and consisted of 4242 bp with 42.9% GC content. The 4.3 kb plasmid DNA sequence was 98% homologous to a plasmid previously isolated from Pasteurella haemolytica.     

Cell-mediated immune response of goldfish, Carassiusaurafus (L.), to Ichthyophthirius multifiliis

Goldfish, Carassius auratus (L.), were intraperitoneally injected with two doses of Ichthyophthirius multifiliis (each containing 2.3 × 10⁶ live tomites) in saline, 30 days apart. The control fish were injected with saline only. Two weeks after the last vaccination, fish of both groups were intradermally injected with 2.5 × 10⁵ live tomites for skin tests. The skin at the antigen-injected site of the vaccinated fish increased in thickness from 8 h onwards and reached a peak at 24 h. Histological study showed a heavy infiltration of mononuclear leucocytes at the antigen-injected site. In contrast, no such changes were encountered in control fish. The migration area of pronephros cells from the vaccinated fish was significantly inhibited, in vitro, compared to controls with the presence of antigens. These findings suggest that the tomite-vaccinated fish produced a cell-mediated immune response. However, vaccinated fish also exhibited significantly higher titres of immobilizing antibodies in their sera and mucus than the controls. Therefore, it is likely that both humoral and cell-mediated immune responses have to work closely together to eliminate the infectious tomites of I. multifiliis which succeed in penetrating the fish epithelial tissues.     

Isolation and characterization of fish Aeromonas hydrophila adhesins important for in vitro epithelial cell invasion

The molecular mechanisms involved in the invasion of Aeromonas hydrophila (strain PPD 134/91) into host cells were studied in vitro using a carp epithelial cell line. Bacterial fractions were extracted with potassium thiocyanate (KSCN) to investigate the adhesins involved. Two groups of adhesins were found. The major group was high molecular weight proteins with the largest component being a 43-kDa protein. Amino terminal sequence analysis indicated that this may have been an outer membrane porin. This supports previous suggestions that a 43-kDa outer membrane protein may be important in adhesion of a human isolate of A. hydrophila . The minor group of adhesins were low molecular weight proteins likely to be less effective in mediating bacterial adhesion and invasion into carp epithelial cells.     

Diagnosis of Borrelia‐associated uveitis in two horses

Borrelia burgdorferi, the etiologic agent of Lyme disease is a tick born spirochetal infection. Clinical signs of Lyme borreliosis are uncommon in horses, but when present they are often vague and nonspecific. In horses, Lyme borreliosis has been implicated in musculoskeletal, neurological, reproductive, and ocular disorders, including uveitis, but definitive diagnosis can be challenging as the causative agent is rarely isolated and serologic tests can be unreliable and do not confirm active disease. Here, we report two cases of equine uveitis associated with B. burgdorferi based on the identification of spirochetes within ocular fluids and confirmed with PCR testing. The two cases illustrate some of the challenges encountered in the recognition and diagnosis of equine Lyme borreliosis. Although only one of many possible causes of equine uveitis, Lyme disease should be considered a differential diagnosis, especially in endemic areas. Given the possibility for false negative results of serum tests during uveitis associated with B. burgdorferi and the failure of such tests to confirm active infection, a combination of cytologic assessment, antibody, and/or PCR testing of ocular fluids may be worthwhile if the clinical suspicion for Lyme uveitis is high.