Neutrophil myeloperoxidase deficiency associated with canine hepatozoonosis

Hepatozoonosis is a very important disease in dogs in Nigeria. Hepatozoonosis was reported in Nigeria in 18 dogs. The clinical signs included fever, anorexia, loss of weight, lameness, oculonasal discharge and conjunctivitis. Hematologic findings included leukocytosis due to neutrophilia and eosinophilia. Parasitemia varied from 1 to 9% of the circulating neutrophils in the peripheral blood smears of the dogs examined. Hepatozoon canis gametocytes were identified in circulating neutrophils of dogs. Peripheral blood smears from dogs confirmed to have natural H. canis infection were cytochemically stained for myeloperoxidase. Parasitized neutrophils were myeloperoxidase deficient while non-parasitized neutrophils were myeloperoxidase positive. This is considered important, because deficiency of the enzyme may be responsible for poor response of H. canis to chemotherapeutic agents.     

THE EFFECT OF SUGARS AND APPLIED CHEMICALS ON HETEROBLASTIC DEVELOPMENT IN IPOMOEA PURPUREA GROWN IN ASEPTIC CULTURE

Seedlings of Ipomoea purpurea were grown in aseptic culture in order to investigate more directly than had been possible in pot culture the effect of carbohydrate and protein nutrition on heteroblastic development which in this species involves a change from entire juvenile to lobed adult leaves. The effect of sugars was to accelerate the development of the adult leaf form while casein hydrolysate retarded it. The growth retardants, AMO-1618 and CCC, also promoted the formation of the adult leaf. These results are discussed in the light of current views on the factors controlling heteroblastic development.     

中国瘿蚊一新种记述(双翅目,瘿蚊科)

记述采自浙江省的端突瘿蚊属Epidiplosis 1新种:指状端突瘿蚊Epidiplosis dactylina sp.nov,.模式标本存放于山东农业大学昆虫标本室.     

Comparison of Endocrine Response to Stress Between Captive-Raised and Wild-Caught Bighorn Sheep

ABSTRACT Stress hormones in Rocky Mountain bighorn sheep (Ovis canadensis canadensis), produced in response to environmental changes, road development, or high population density, may impact their immune systems to a threshold level that predisposes them to periodic, large-scale mortality. We compared the stress response to a novel environmental situation and repeated handling between bighorn sheep born and raised in captivity (CR) and bighorn sheep born in the wild (WC) and brought into captivity. We measured plasma epinephrine, norepinephrine, cortisol, and fecal glucocorticoid metabolites (FGM). Three weeks after each group's arrival we used a one-time drop-net event to elicit an acute stress response, and we collected blood samples from each sheep over 35 minutes, as well as one fecal sample. We collected blood and fecal samples from both groups on 7 other occasions over the subsequent 6 months. We also collected fecal samples from the pen at approximately 24-hour intervals for 3 days following every handling event to monitor the stress response to handling. We found that CR sheep had a stronger autonomic nervous system response than WC sheep, as measured by epinephrine and norepinephrine levels, but we found a very similar hypothalamic-pituitary–adrenal axis (HPA) response, measured by cortisol levels, to the acute stress event of a drop-net restraint. We also found that once the WC sheep had acclimated, as indicated by the return to the initial baseline FGM levels within 12 weeks, the CR and WC groups' HPA responses to sampling events were not significantly different from one another. Fecal samples can provide a noninvasive mechanism for managers to monitor baseline FGM for a given herd. Using long-term monitoring of FGM rather than values from a single point in time may allow managers to correlate these levels to outside influences on the herd and better understand the impacts of management changes, population density, or increased human developments on the health of the sheep population.     

Fluorescent vital staining of plant sexual cell nuclei with DNA—specific fluorochromes and its application in gametoplast fusion

DNA－binding fluorochromes are often used for vital staining of plant cell nuclei.However,it is not always sure whether the cells after staining still remain in living state.We chose several criteria to estimate the validity of real vital staining for sexual cell nuclei.These were:the cytoplasmic streaming in pollen tubes whose nuclei were stined,the simultaneous visualization of fluorochromatic reaction and nucleus staining in isolated generative cells,and the capability of isolated.prestained generative or sperm cells to fuse with other protoplasts.The results confirmed that 4,6-diamidino-2-phenylindole(DAPI),Hoechst 33258 and mithramycin could be used as real vital stains,though their efficiency varied from case to case;among them DAPI showed best effect.The fluo rescent vital staining technique offered a useful means foridentification and selection of heterokaryons in gametoplast manipulation studies.     

光合细菌和小球藻对石生苔藓种源扩繁的作用

石生苔藓结皮可以从大气中吸收水分及养分，附着在岩石表面生长，具有促进矿物分化和植被演替等多种重要的生态功能，利用人工培育的苔藓结皮进行岩石工程创面生态修复具有广阔的市场前景，而针对特定地区的优势种探讨高效的种源扩繁技术则成为了首要任务。研究以秦岭北麓长势好、生物量大的石生匍匐型藓种羽枝青藓为研究材料，考虑沼泽红假单胞菌浓度(高浓度24 mL/L,低浓度12 ml/L,不添加)和小球藻浓度(高浓度250 mL/L,低浓度125 mL/L,不添加)开展双因素完全试验，观测人工气候箱条件下羽枝青藓的盖度、新发芽数和新发芽茎长，探究沼泽红假单胞菌和小球藻对羽枝青藓的作用效果、最适浓度及组合，为提高羽枝青藓扩繁效率提供科学依据。结果显示，(1)只添加低浓度沼泽红假单胞菌的处理羽枝青藓生长状况最优，相比于对照处理(不添加沼泽红假单胞菌和小球藻),可将盖度提高14.3%,新发芽数增加61.2%,新发芽茎长增长34.0%;(2)沼泽红假单胞菌浓度对羽枝青藓的盖度、新发芽数和新发芽茎长均有显著影响；(3)小球藻浓度对羽枝青藓各项生长指标均无显著影响，其与沼泽红假单胞菌的交互作用对羽枝青藓盖度有显著影响。...     

基于基质辅助激光解吸/电离飞行时间质谱的猪呼吸道病毒多目标鉴定方法的建立和应用北大核心

【目的】建立能高效同步鉴定猪伪狂犬病毒(porcine pseudorabies virus,PRV)、猪圆环病毒2型(porcine circovirus 2,PCV-2)和3型(porcine circovirus 3,PCV-3)、非洲猪瘟病毒(African swine fever virus,ASFV)以及猪博卡病毒1型(porcine bocavirus group 1,PBoV-G1)、2型(porcine bocavirus group 2,PBoV-G2)和3型(porcine bocavirus group 3,PBoV-G3)等呼吸道病毒的核酸基质辅助激光解吸/电离飞行时间质谱(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF MS)高通量多目标检测技术。【方法】根据7种病原体基因的保守序列,分别设计不同病原的引物及对应的单碱基延伸探针,通过引物浓度和反应条件优化,方法特异性、敏感性和稳定性分析,以及临床样本和猪源产制品的检测验证,建立常见猪呼吸道DNA病毒的MALDI-TOF MS多目标检测体系。【结果】质谱分析显示,多目标检测体系的7种靶标产物峰只在特定病毒阳性样品检测时产生,与其他病原体检测无交叉反应,表明该方法对7种靶标病毒检测特异性良好。重复性试验结果分析显示,体系中每种病毒在高、中、低浓度时批内阳性符合率均≥98.0%,批间均≥98.3%,表明该方法具有较高的稳定性。体系中7种病原体每种病毒最低检测限在8.65–26.27拷贝/μL之间,与荧光PCR(real-time fluorescence quantitative PCR,RT-qPCR)检测方法相当。采用MALDI-TOF MS多重检测方法对100份组织、饲料和猪肉样品进行检测应用,检出2种及以上混合感染样品39份,其中5份样本同步检出5种病原体阳性;对8份ASFV-p72假病毒人工污染样品进行验证,均可检出ASFV阳性。将以上样本检测应用结果与荧光PCR方法进行比对验证,2种方法对于不同病原体检测结果的符合率高达94.4%–100%。【结论】本研究建立的基于MALDI-TOF MS的猪呼吸道常见DNA病毒多重检测方法为猪群相关疫病快速监测和鉴别诊断,以及便利化进出口动物检疫等提供了一种新的敏感、特异的高通量多目标检测技术。     

代谢互养关系在维持微生物物种多样性中的作用

互养关系（cross-feeding）是微生物物种之间普遍存在的一种相互关系，其中物种利用环境中其他成员的代谢产物以促进自身生长的情形称为代谢互养关系，这种关系对物种间的竞争结果往往有很大影响，甚至会改变种群结构。为了研究代谢互养关系在维持微生物物种多样性中的作用，构建包含不同代谢互养关系的资源竞争模型，这些模型既体现了微生物物种竞争资源时种群密度及资源量的动态，也展示了物种利用其他竞争者的代谢资源对自身生存状况的影响。数值模拟结果显示：（1）考虑微生物中不同的代谢互养关系结构：两物种间单向互养、双向互养以及多物种间的互养，不同的互养关系都可以促进竞争物种稳定共存，竞争中处于劣势的物种通过利用其他竞争成员的代谢产物，打破外界资源量对其生长的限制，改变原本消亡的命运；而处于优势的物种则通过利用其他竞争成员的代谢产物，增大种群密度。（2）多物种竞争同一种有限资源时，不是所有物种都能共存，在四物种模拟中，原本处于最劣势的物种灭绝，其余三者共存。物种产生代谢资源对其本身是"不利"的，如果在模拟中物种利用代谢资源的能力相同，那么物种竞争外界资源的劣势就很可能无法被抵消。通过改变资源利用率发现只有互养关系中代谢资源的利用可以弥补劣势种在竞争外界资源时的不足，多物种才可以全部共存。（3）验证数值模拟结果的普遍性，分析参数变化对共存的影响，结果表明代谢互养关系促进的共存对代谢资源相关参数不敏感，参数的改变只影响平衡态时物种的种群密度。所以，代谢互养关系可以促进相互竞争的微生物物种共存，即微生物之间的互养关系很可能是维持物种多样性的一种机制。