日粮中添加不同纤维分解菌对鹅生产性能的影响

为研究日粮中添加不同纤维分解菌对鹅生产性能的影响,试验选用0日龄健康农安本地鹅64只,随机分成4组,每组16只。试验组从0日龄每3 d饲喂一次纤维分解菌,喂菌量为10⁹ CFU/mL,纤维分解菌分别为:从鹅肠道内分离扩增的芽孢纤维分解菌(A组);从白蚁肠道内分离扩增的芽孢纤维分解菌(B组);从牛粪中分离扩增的芽孢纤维分解菌(C组);对照组用等量的蒸馏水代替。测定鹅日增重、采食量、料重比。结果表明,A、B、C组提高了鹅的日增重、采食量,显著降低了料重比,B组作用效果较好、A组次之,C组较差。     

细菌IV型分泌系统结构的研究进展

革兰氏阴性菌的IV型分泌系统（T4SS）是一个由ATP供能,多种蛋白质复合构成的体系,该体系能够跨过整个细胞外膜、分泌大量底物。详细阐述了T4SS组成元件的结构,如底物转运通道、核心复合物、外膜复合物、内膜复合物、菌毛等。T4SS更大组成元件、其他结构、组成元件间相互作用的机理等有待进一步研究。     

食源性病原及其毒素检测技术研究进展

食源性病原包括细菌、真菌、病毒、朊病毒和原虫,它们在生产加工及储运环节污染食物,同时不断分泌包含毒素在内的各种成分到细胞外直至自身死亡和裂解,其中一些病原菌及其毒素能耐受复杂的食物加工,直至进入人体干扰细胞生理过程并引发疾病。详细介绍了如何利用各种"组"学(包括蛋白质组、肽组、代谢组和食品组学)技术检测和寻找食源性病原微生物的生物标志物,深入了解其产毒机理、毒力和致病机理,及对胁迫的适应能力。这对于追踪食源性病原微生物内、外毒素的来源,保证食品安全并控制食源性疾病爆发具有重要意义。     

病菌侵染拟南芥对光系统Ⅱ的损伤

[目的]研究病菌对植物的侵染对于培育高抗农作物新品种的重要意义。[方法]将病菌稀释液注入培养拟南芥幼苗的小瓶中,在不同时间监测植物的呼吸作用、光合作用及光系统Ⅱ的变化。[结果]病菌侵染拟南芥幼苗以后,呼吸作用速度普遍增加,呼吸作用速度增高能够提供更多的ATP以供植物抗病的需要。植物在受到病菌侵染以后也需要比平时更多的同化产物。此时需要光合作用速度提高,光合效率增加。但是病菌侵染以后,光合作用普遍降低。病菌侵染拟南芥幼苗以后,光系统Ⅱ的最大效率及通过光系统Ⅱ的光能所占光总量的比例普遍降低,光系统Ⅱ受到损伤,受到损伤的光合器官不能进行正常的光合作用。植物抗病对同化产物需要量的增加与植物光合器官受损伤而不能满足之间的矛盾最终会导致植物受侵染部位的坏死。[结论]病菌侵染拟南芥幼苗以后,光系统Ⅱ的最大效率及通过光系统Ⅱ的光能所占光总量的比例普遍降低,光系统Ⅱ受到损伤。     

产酶微生物及其应用

介绍了产生纤维素酶和漆酶的真菌和细菌种类,以及各种酶在制浆造纸、饲料工业、污水治理、纺织洗涤、食品和堆肥等领域的应用情况。     

In Vitro Evaluation of the Antibiotic Activity of Combinations of Ophthalmic Drugs Against Common Equine Ocular Pathogens

A subpalpebral lavage catheter is commonly used to administer medications in the treatment of infectious keratitis in horses. Drugs may mix in the subpalpebral lavage catheter, potentially affecting antimicrobial efficacy. The objective of this study was to determine the in vitro antimicrobial efficacy of combinations of commonly used ophthalmic preparations. An agar gel diffusion bioassay was used to determine the antibiotic activity of a number of antimicrobial, antifungal, mydriatic, and antiproteinase drug combinations. Drug mixtures were allowed to sit in a syringe at ambient temperatures and room lighting, for 1 (T1) and 6 hours (T2). The antibacterial efficacy was determined by measuring the zone of inhibition around wells containing the drug combinations after overnight incubation at 37°C and comparing them with the zone of inhibition around the antimicrobial alone. Combinations were tested against Pseudomonas aeruginosa and Streptococcus zooepidemicus. There was no significant decrease in the zone of inhibition, compared with controls, for the majority of combinations tested. Significantly smaller zones of inhibition were identified for the following combinations: (1) tobramycin, cefazolin, natamycin, and serum (T1) and (2) tobramycin, cefazolin, natamycin, serum, and atropine (T1) compared with tobramycin alone; (3) ciprofloxacin, cefazolin, natamycin (T1) compared with ciprofloxacin alone; (4) triple antibiotic ophthalmic solution (TAB) and natamycin (T6); (5) TAB, natamycin, and serum (T6); and (6) TAB, natamycin, serum, and atropine (T6) compared with TAB alone. Admixture does not affect in vitro antibacterial efficacy for the majority of ophthalmic preparations, although efficacy of TAB may be decreased compared with the drug alone.     

花卉提取物对3种细菌的抑菌性测定

利用丙酮超声波提取和减压浓缩技术,获得17种花卉茎、叶的提取物,分析各提取物对3种细菌的抑菌结果。天竺葵(Pelargonium graveolens)对腐生葡萄球菌(Staphylococcus saprophyticus)和藤黄葡萄球菌(Micro-coccus luteus)具有抑制作用;杜鹃(Rhododendronsimsii R.spp.)对腐生葡萄球菌和炭疽杆菌(Bacillus anthracis)具有抑制作用。天竺葵提取物4种供试质量浓度对腐生葡萄球菌的抑菌率均达96%以上,杜鹃提取物对炭疽杆菌的抑菌率在77%~84%之间。但天竺葵、杜鹃提取物分别对炭疽杆菌和藤黄葡萄球菌无抑制效果。2种花卉提取物抑菌率卡方检验结果表明,不同质量浓度的天竺葵提取物对藤黄葡萄球菌抑菌率差异显著;杜鹃提取物不同质量浓度间对腐生葡萄球菌的抑菌率差异显著。     

杉木人工林凋落物中微生物数量对间伐的响应

为了明晰凋落物中微生物数量对间伐强度的响应程度,以南京溧水林场间伐7 a后25年生的杉木(Cunninghamia lanceolata(Lamb.)Hook.)人工林为对象,研究了不同间伐强度对凋落物中真菌、细菌、放线菌3类微生物数量季节性变化的影响。结果表明:不同强度间伐杉木人工林下凋落物中微生物的数量随季节变化差异显著,微生物数量在春季期间对间伐响应最为显著。与对照相比,春季内弱度间伐下细菌数量显著减少了61.05%(P0.01);而春季内中度间伐下的真菌和细菌数量分别减少了25.32%(P0.01)和36.14%(P0.01),放线菌则增加了30.97%(P0.05);春季内强度间伐下真菌量和放线菌数量分别增加了77.64%(P0.05)和59.35%(P0.01),细菌数量减少了42.11%(P0.01)。其中,凋落物层温度及林下植被层Margalef指数对微生物数量的影响最为显著。微生物数量的影响会导致凋落物向土壤中输送的养分不同,对提高林分生产力有重要意义。     

Starved bacteria retain their size but lose culturability - Lessons from a 5000 years old undisturbed A-horizon

The vast majority of soil bacteria are unable to form visible colonies on agar media. One hypothesis is that unculturable soil bacteria are dwarf cells that may either be small starved forms derived from larger species or represent inherently small species. We test the hypotheses that cells of extremely starved soil bacterial communities are smaller and less culturable than cells of bacterial communities from a richer soil, and that culturability is related to cell size by comparing an extremely starved community from a 5200-year-old A-horizon buried under a burial mound with a community from a modern agricultural A-horizon.We serially filtered cell suspensions through filters with successively smaller pore sizes (0.8 μm, 0.6 μm and 0.4 μm) and assessed total cell number and culturability, i.e. the ability to form colonies on two types of agar media, in each size fraction. Cell size distributions were assessed in unfiltered suspensions. Average cell size was only moderately reduced in the starved community, where culturability was low for all size classes. In contrast, culturability was much higher in the modern community, where culturability decreased dramatically with decreasing cell sizes.     

The under-recognized dominance of Verrucomicrobia in soil bacterial communities

Verrucomicrobia are ubiquitous in soil, but members of this bacterial phylum are thought to be present at low frequency in soil, with few studies focusing specifically on verrucomicrobial abundance, diversity, and distribution. Here we used barcoded pyrosequencing to analyze verrucomicrobial communities in surface soils collected across a range of biomes in Antarctica, Europe, and the Americas (112 samples), as well as soils collected from pits dug in a montane coniferous forest (69 samples). Data collected from surface horizons indicate that Verrucomicrobia average 23% of bacterial sequences, making them far more abundant than had been estimated. We show that this underestimation is likely due to primer bias, as many of the commonly used PCR primers appear to exclude verrucomicrobial 16S rRNA genes during amplification. Verrucomicrobia were detected in 180 out of 181 soils examined, with members of the class Spartobacteria dominating verrucomicrobial communities in nearly all biomes and soil depths. The relative abundance of Verrucomicrobia was highest in grasslands and in subsurface soil horizons, where they were often the dominant bacterial phylum. Although their ecology remains poorly understood, Verrucomicrobia appear to be dominant in many soil bacterial communities across the globe, making additional research on their ecology clearly necessary.