Repurposing Ionophores as novel antimicrobial agents for the treatment of bovine mastitis caused by Gram‐positive pathogens

Increasing reports of multidrug‐resistant bacterial infections in animals has created a need for novel antimicrobial agents that do not promote cross‐resistance to critically important antimicrobial classes used in human medicine. In response to the recent emergence of antimicrobial resistance in several bovine mastitis pathogens, in vitro antimicrobial susceptibility was determined for four polyether ionophores (lasalocid, monensin, narasin and salinomycin) against Staphylococcus spp. and Streptococcus spp. isolated from clinical cases. In addition, erythrocyte haemolysis and WST ‐1 cell proliferation assays were used to assess in vitro mammalian cell cytotoxicity and biofilm susceptibility testing was performed using the minimum biofilm eradication concentration (MBEC ?) biofilm assay. Lasalocid, monensin, narasin and salinomycin exhibited bacteriostatic antimicrobial activity against all pathogens tested, including methicillin‐resistant staphylococci, with MIC ₉₀ values <16 μg/ml. Narasin and monensin displayed the least toxicity against mammalian cell lines and all compounds significantly reduced viable cell numbers in a Staphylococcus aureus biofilm. Based on in vitro characterization, all four ionophores offer potentially novel treatments against bovine mastitis but in vivo studies will be essential to determine whether acceptable safety and efficacy is present following intramammary administration.     

罗非鱼类立克次氏体病的组织病理学观察

本文主要研究感染类立克次氏体(Rickettsia-like organism,RLO)的养殖罗非鱼(Oreochromis aureus♂×Oreochromis niloticus♀)肝、脾、肾、肠、鳃和心脏的组织病理变化。感染类立克次氏体的罗非鱼各器官广布粗糙不圆整的白色小结节,这些结节为肉芽肿坏死灶,分层不典型,与周围健康组织的界限不甚明显;严重病变的组织坏死区域较大,与周围明显增生的细胞形成清晰的巨大"肉瘤"状肿物。经吉姆萨-瑞氏染色后,在病变组织内,尤其是脾肾组织的巨噬细胞胞质内可见蓝紫色球状或颗粒样、成簇分布的类立克次氏体。这些发现可为罗非鱼类立克次氏体病的病理学诊断提供依据。     

广西南宁市水牛肝脏内前后盘吸虫的鉴定

为探明广西南宁地区水牛体内前后盘吸虫的种类，通过对其肝脏来源虫体进行鉴定，确定水牛感染的具体种属。本研究对南宁市某屠宰场水牛肝脏进行剖检、病理观察，并采集肝脏内寄生的前后盘吸虫进行虫卵孵育，对孵育所得的虫卵及虫体进行形态观察，对成虫虫体进行HE及苏木素染色，观察其内部的结构，并采用分子生物学方法对成虫进行鉴定。结果显示，虫体感染的肝脏表面有出血点，且呈现淤血、化脓灶、肝脏肿大、质地偏软等肉眼可见病变。虫卵呈椭圆形、淡灰色、有卵盖且内含圆形胚细胞，卵黄细胞不充满整个虫卵。对成虫染色观察可见虫体由体壁及内部生殖、消化等系统构成。体壁由皮层和肌层组成，虫体可见生殖系统、消化管和一些肌束与纤维组织，其中生殖系统包括卵巢、子宫和睾丸等生殖器官，消化管分布于整个体腔。虫体核糖体基因ITS-2扩增产物为441 bp，分析显示与GenBank中Explanatum explanatum（AB743577.1）相似性达99.3%。遗传进化分析显示此虫体与Explanatum explanatum具有很近的亲缘关系，同属一个分支。综合剖检病理变化，虫卵特性，虫体形态特性及分子生物学结果，确定该虫体为前后盘科的Explanatum explanatum。本研究结果为前后盘科吸虫分类鉴定提供一定的理论基础，并进一步丰富该科的虫体种类，此外初步了解广西南宁地区水牛前后盘吸虫病的流行情况，并为准确防治吸虫感染提供一定的理论依据。     

马睾丸石蜡切片制作前期处理条件的优化

目的优化石蜡切片制作前期处理——固定和脱水条件。方法对比Bouin固定液与4%多聚甲醛两种不同固定液在4 ℃和室温不同时长下的固定效果;对比6 h和18 h时长的脱水效果。结果4%多聚甲醛4 ℃固定24 h后进行18 h脱水或Bouin 4 ℃或者常温固定24 h后进行6 h脱水均能达到有效支持后期石蜡切片制作的目的。结论Bouin固定液常温固定24 h后进行6 h脱水处理可作为野外采取马睾丸组织制作石蜡切片最佳的前期处理方案。     

绵羊毛囊凋亡及抑制的原因初探

为探索在毛囊细胞凋亡中雌激素和褪黑素的作用,实验通过对不同浓度的雌激素和褪黑素水平下体外培养绵羊皮肤的免疫组化染色,发现0.01～0.5 μg/mL雌激素均导致了毛囊和皮脂腺的凋亡,10-4mol/L褪黑素显著抑制了0.01 μg/mL雌激素引起的凋亡,却不能抑制0.5 μg/mL雌激素引起的凋亡.说明雌激素和褪黑素是毛囊周期调控的两个重要激素,它们之间通过相反的作用方式,即通过促进和抑制凋亡来调节毛囊的周期性变化.     

人参种子的贮存特性

新采集的人参干籽含水量7．8％，硅胶干燥脱水使其含水量分别降至5．0％和3．0％。经过干燥脱水的种子TTC染色百分率同未经干燥的种子相比，没有差异，均为100％，脱氢酶活性略有升高。3种含水量的种子在室温，0℃和～10℃保存一年后，各处理之间的TTC染色百分率没有明显差异，均在90％以上。在3种温度保存1年后，含水量7.8％的种子脱氢酶活性均最低。试验证明只要干燥脱水方法得当，人参种子含水量降至3．0％，不损害种了生活力，并可在-10℃低温保存，具有同正常型种子一样的对干燥和低温的忍耐能力，应该划为正常型种子。     

猪附红细胞体病继发猪肺疫的诊断与防治

根据病猪的临床症状和病理剖检变化,有目的的进行了一系列的实验室检查,及时的对疫病做出了确切诊断。并且提出了有效的治疗混合感染的措施和预防方法,大大地降低了因混合感染造成的经济损失。     

Comparison of 4 fixation and staining methods for the cytologic evaluation of ear canals with clinical evidence of ceruminous otitis externa

BACKGROUND: Swab cytology of ear canals is one of the most useful and rapid methods to assess the presence of external ear infections. Smears are generally stained with rapid Romanowsky-type stains, with or without prior heat fixation. OBJECTIVES: The aim of this study was to compare 4 different methods of fixation and staining of ear swab cytology samples from dogs. METHODS: Eight dogs with otitis externa were selected from a dermatology referral population. A cotton swab was used to obtain ceruminous material from 12 ear canals. Four smears of each swab were prepared on glass slides (randomly identified as A, B, C, or D) and air-dried for cytologic examination. Samples marked A were stained with Dip Quick (Jorgensen Laboratories Inc, Loveland, CO, USA) after heat fixation; samples marked B were stained without heat fixation; samples marked C were heat-fixed and dipped only in the counterstain (the blue reagent) of Dip Quick; and samples marked D were dipped only in the counterstain, without heat fixation. Ten high-power fields (hpf; X100 oil immersion objective) in each slide were evaluated by 2 observers, and total numbers of keratinocytes, yeast, bacteria, and neutrophils were counted. Statistical comparison was performed using an ANOVA model applied after verifying the normal distribution of the data, and using nonparametric sign tests and Wilcoxon signed rank tests. RESULTS: No statistically significant differences were observed in the numbers of keratinocytes, yeast, bacteria, or neutrophils among the 4 staining methods (P > .05), although significant interobserver differences were found. CONCLUSION: We conclude that heat fixation does not improve the quality of ceruminous ear swab samples for cytologic evaluation, and propose a 1-step dip in the blue reagent alone as a rapid method of staining samples from canine ear canals.     

超声波预处理对水酶法提取扁桃仁油及水解蛋白影响的研究

以扁桃仁为原料,在水酶法提取扁桃仁油及水解蛋白前对原料进行超声波预处理。通过单因素试验与正交试验,确定最佳处理条件为:超声波功率300 W,温度40℃,时间15 min。在此条件下,扁桃仁油与水解蛋白提取率分别为80.43%和89.59%,比未经超声波预处理分别提高4.4%和5.2%。通过番红染色法观察了超声波与纤维素酶对原料细胞的破坏效果。