锦鲤源铜绿假单胞菌的分离鉴定及药敏试验

对从发病锦鲤分离出的病原菌主要形态与生理生化特性、16S rRNA基因序列及耐药特性等进行了研究,旨在为锦鲤疾病防治提供理论依据,对铜绿假单胞菌的进一步研究提供基本资料。发病锦鲤体长37~42 cm,体重1.5~2.0kg,眼球脓肿凸出,鳃丝被轻微腐蚀,其上可见附着物,肛门红肿并伴有黄色粘液流出。健康锦鲤体长7~10cm,体重(25±3)g。分离到的1株形态一致优势生长菌株（记为HL2）呈现圆形光滑、边缘整齐、中央隆起、略透明、乳白色,直径约1.4mm。分离菌经革兰氏染色镜检,均为革兰氏阴性、短杆状。肌肉注射感染后,供试健康锦鲤14d内全部死亡,并在试验后期注射部位轻微出血,眼球周边有白浊及化脓的现象。HL2有运动性,精氨酸脱羧酶、鸟氨酸脱羧酶、精氨酸双水解酶阳性,苯丙氨酸脱羧酶阴性,发酵麦芽糖、甘露醇、蔗糖、半乳糖等,不发酵侧金盏花醇与阿拉伯糖等。分离株HL2的序列长度为1461bp(GenBank登录号为KF413420),在系统发育树上与铜绿假单胞菌（KC959478）聚为一支。头孢曲松、卡那霉素、四环素等35种药物有效抑制HL2,庆大霉素、强力霉素、头孢拉定等5种药物具有一定的抑菌作用,青霉素G、氨苄西林、头孢唑林等15种药物无效。使用抗生素时必须更加科学、合理、有效;从药物选择、使用剂量、用药疗程等方面着手,以减少耐药菌株的产生。     

南黄海族小黄鱼昼夜渔获率差异的统计学分析

利用2004年度东海区重点渔场底曳拖网渔业资源监测资料,从中选用小黄鱼网次渔获率作为指标值,应用LSD方法对南黄海族小黄鱼昼夜渔获率差异进行了统计学分析,以揭示小黄鱼昼夜的活动规律。结果表明,小黄鱼在不同的洄游阶段昼夜网次间渔获率无显著性差异,昼夜无垂直移动现象,常年处于底层,为典型的底层鱼类;在利用底曳拖网船进行渔业资源调查时,无需修正昼夜网次间小黄鱼的渔获率,用获取的调查数据即可估算资源量。     

Pathogenicity of white spot syndrome virus on postlarvae and juveniles of Penaeus (Litopenaeus) vannamei

White Spot Syndrome Virus (WSSV) has decimated the shrimp aquaculture around the world. Breeding efforts to generate resistant stocks are necessary but there is a lack of basic information on challenge test strategies focused on genetic selection. Infection routes and developmental stages were evaluated on Penaeus vannamei as a first step in a strategy to select white spot virus (WSSV)-resistant stocks. Mortalities could not be induced before the PL30 stage. The impact of infection by immersion and blended tissue was intermediate on mortalities when compared to the minced tissue treatment on PL30. Blended and minced tissue treatments produced the highest mortalities on PL40 while immersion was intermediate. A general tendency towards higher susceptibility associated with older stages was detected. Additionally, juveniles of 1 g average weight from three local breeding programs were challenged. There were no differences in survival between the programs, although two of them derived their progenies from survivors of strong WSSV events. The implications of these results to the WSSV epidemiological characteristics and breeding programs are discussed.     

The effectiveness of a new physical property evaluation method of kamaboko which applied the principal component analysis to the puncture and stress relaxation tests

ABSTRACT:   The physical properties of 49 commercial kamabokos were measured by the puncture and stress relaxation tests. The principal component analysis was applied to the physical parameters of both tests, and their cumulative contribution ratios were over 90% with the first and second principal components, respectively. The comparison among the kamabokos was carried out using the synthetic physical parameters. The kamabokos produced in same area showed the peculiar distribution. The relative positional relation of kamabokos measured by the stress relaxation test was different from that by the puncture test for many of the kamabokos. Physical property evaluation using a principal component analysis is very effective for intensiveness of many measurement parameters. If much more kamabokos were measured by this method, regional characteristics of kamabokos would be clarified.     

微波辅助法提取剑叶龙血树茎总黄酮的工艺研究

对微波辅助法提取剑叶龙血树茎中黄酮类物质进行了研究,通过单因素及L9(34)正交实验,得到提取最佳工艺为:温度50℃,微波功率420 W,乙醇浓度90%,料液比1:10,提取时间8 min,此条件下剑叶龙血树茎总黄酮提取率为1.20%。     

乌龟鲍曼不动杆菌的分离鉴定及药敏试验

自患病乌龟肝脏中分离出1株优势菌DL01221,对其进行形态学观察、生化试验、16SrRNA基因序列分析,同时采用Kriby-Bauer纸片扩散法进行药物敏感性试验。试验结果表明,该菌为革兰氏阴性球杆菌,将该菌株16SrRNA序列进行同源性和系统进化树分析,发现它与鲍曼不动杆菌处于同一群,同源性超过98%,结合菌株形态和生化指标,确定该菌株为鲍曼不动杆菌。致病性试验结果显示,其对乌龟具有较强的致病作用;耐药性结果显示其对头孢他啶、卡那霉素及氟罗沙星敏感,对其他多种抗生素耐药。     

Utility of 2 Immunological Tests for Antemortem Diagnosis of Equine Protozoal Myeloencephalitis (Sarcocystis neurona Infection) in Naturally Occurring Cases

Background: Antemortem diagnosis of equine protozoal myeloencephalitis (EPM) is challenging. Limited information is available regarding a commercial test (surface antigen 1 [SAG‐1] ELISA). Performance of another commercial test (indirect fluorescent antibody test [IFAT]) using samples from an independent group has not been well described. Hypothesis/Objectives: The primary goal was to evaluate the SAG‐1 ELISA and IFAT using naturally occurring EPM cases. A secondary goal was to obtain more information regarding clinical presentation. Animals: Hospital cases were admitted over 20 months and classified into 4 groups. Confirmed positive cases (n = 9) had asymmetric or multifocal neurologic deficits or both and postmortem lesions consistent with EPM. Confirmed negative cases (n = 17) had variable clinical signs and postmortem lesions consistent with another neurologic disease (or no lesions). Suspected positive cases (n = 10) had asymmetric or multifocal deficits or both, marked improvement after treatment for EPM, and other likely diseases excluded. Suspected negative cases (n = 29) had orthopedic disease and no neurologic deficits. Methods: Results of immunological testing (SAG‐1 ELISA and IFAT on serum or cerebrospinal fluid [CSF] or both), neurologic examinations, CSF analyses, and postmortem examinations were analyzed retrospectively. Results: SAG‐1 ELISA sensitivity was 12.5% (95% CI, 1.6–38.4) and specificity was 97.1% (95% CI, 84.7–99.9) using serum. IFAT sensitivity was 94.4% (95% CI, 72.7–99.9) and specificity was 85.2% (95% CI, 66.3–95.8) using serum; sensitivity was 92.3% (95% CI, 64.0–99.8) and specificity was 89.7% (95% CI, 72.7–97.8) using CSF. Conclusions and Clinical Importance: Low sensitivity of the SAG‐1 ELISA limited its usefulness for antemortem diagnosis of EPM in this patient population.     

鲟源致病性鲁氏耶尔森菌的分离、鉴定及药敏研究

2017年,新疆阜康市某鲟鱼养殖场的西伯利亚鲟出现大批死亡,主要症状为生殖孔红肿外突,腹部有点状出血。自患病西伯利亚鲟肝脏、脾脏分离到一株优势菌株XB2,通过革兰氏染色、生理生化试验、药敏试验,并对其16S rRNA基因序列进行测定,用Mega 6.0对序列进行分析。生理生化试验结果显示,菌株XB2为革兰氏阴性短杆菌,单独或成对出现;产酸不产气,V-P反应呈阳性,能利用蔗糖、果糖、葡萄糖、明胶、枸橼酸;在含1%(m/V)氯化钠中能生长,高于3%(m/V)氯化钠中不生长;在4℃不生长,20～30℃均能生长,但在37℃不生长;不利用乳糖、水杨苷、纤维二糖、硫化氢、酒石酸、阿拉伯糖。进化树显示,菌株XB2与鲁氏耶尔森菌KJ812974同源性达99%。通过回感试验确定其半致死密度为2.37×104 cfu/mL。结合生理生化鉴定结果和16S rRNA基因序列分析结果,确定菌株XB2为鲁氏耶尔森菌。药敏结果显示,鲁氏耶尔森菌XB2对氟苯尼考、左氧氟沙星、哌拉西林、阿洛西林等9种药物敏感,对麦迪霉素、大观霉素、链霉素、氨苄西林等15种药物耐药。     

The fate of chlortetracycline residues in a simulated chicken–fish integrated farming systems

Two experiments were conducted at the Asian Institute of Technology, Pathumthani, Thailand to investigate the fate of chlortetracycline (CTC) residue in chicken manure and its effect on integrated chicken–fish farming system. During the first experiment, broiler chickens were raised and CTC residues in their manure were analysed. Chicken fed diets containing 0, 50, 200 and 800 CTC mg kg^?1 had CTC residue levels of 0, 0.9, 3.8 and 6.5 CTC ng g^?1. Once the diet containing CTC was withdrawn, CTC in the manure dropped to negligible amounts (0, 0, 0.2 and 0.5 CTC ng g^?1) within 1 day. Integrated chicken–fish farming systems were simulated during the second experiment to determine the fate of antibiotic residues in chicken manure in aquaculture environment. Chickens were fed a CTC‐free diet and a feed containing CTC at 200 mg kg^?1. Ten 4 m³ square concrete tanks (2 × 2 × 1 m) were used for the experiment. Five tanks were fertilized with CTC‐contaminated manure and the remaining five tanks were fertilized with CTC‐free manure at a rate of 100 kg dry matter ha^?1 day^?1. Sex‐reversed Nile tilapia (Oreochromis niloticus) was stocked at 12 fish tank^?1 on the 14th day after chicken manure application. The immuno‐radio microbial receptor assay (Charm II test) revealed that edible fish muscle, fish intestinal tract and sediment were contaminated by CTC at rates of 7.21, 22.104 and 1.788 ng g^?1, respectively, after 45 days. Chlortetracycline was detected on day 20 in the water column and gradually increased from 0.26 to 12.13 ng g^?1. Chlortetracycline residues were not detected in fish or the aquatic environment of the CTC‐free treatment. The results demonstrate the potential for antibiotic residue accumulation in fish and aquatic environment when CTC‐contaminated chicken manure is used for pond fertilization.     

Linking spatial pattern of bottom fish assemblages with water masses in the North Sea

Understanding the links between large scale spatial structuring of fish assemblages and shaping factors is essential to develop comprehensive ecosystem-based fisheries management. In this study, we investigated spatial patterns of bottom fish assemblages in the North Sea in relation to prevailing water masses in the region. We based our analysis on catch data from the German Small-Scale Bottom Trawl Survey conducted between 1987 and 2005 and used both ordination techniques and Mantel tests. Spatial variability of bottom fish assemblages was larger than inter-annual variability. Five significantly different bottom fish assemblages were associated with the following prevailing hydrographical regimes: i) the English Channel, ii) Continental Coastal, iii) central North Sea, iv) northern North Sea, and v) northern Atlantic water masses. Associations were generated by gradients in relative proportions of abundant species such as grey gurnard ( Eutrigla gurnardus ), dab ( Limanda limanda ), whiting ( Merlangius merlangus ), haddock ( Melanogrammus aeglefinus ) and Norway pout ( Trisopterus esmarki ). Taking into account large scale spatial structuring of catch data Mantel tests confirmed significant correlation between the fish assemblages and hydrographical variables. In summary, our results strongly support the hypotheses that hydrographical features such as water masses, fronts, and residual currents could shape bottom fish associations in the North Sea. Spatial demarcations of bottom fish assemblages indicated by this study can be used to support ecosystem-based fisheries management strategies.