牧草联合固氮研究概况

联合固氮是草原土壤氮素的重要来源,但是目前对于牧草联合固氮方面的研究却仍然比较滞后。综述了牧草联合固氮菌的种类、固氮酶活性、对牧草的促生作用、影响固氮的因素等方面的研究概况,以期能够引起人们对牧草联合固氮菌的重视。     

结缕草根际联合固氮菌的分离及初步鉴定

联合固氮菌在植物根际土壤生长或定植于植物根表细胞,这类细菌可将空气或土壤中的氮素转化为氨态氮供植物直接吸收利用.结合气相色谱仪,利用乙炔还原等方法对结缕草根际联合固氮菌进行了分离和鉴定.结果表明:从结缕草根际土壤中分离获得9株联合固氮菌株,菌株的固氮酶活性相差较大,为67.5～343.7 C2H4nmol/(ml·h)...     

高寒地区燕麦根际联合固氮菌研究Ⅰ固氮菌分离及鉴定

结合气相色谱仪,利用乙炔还原等方法对高寒地区重要饲用植物--燕麦(Avena sativa)根际联合固氮菌进行了分离和鉴定.结果表明,该地区燕麦根际联合固氮菌株较少(8株),菌株分布以根系表面(RP)最多,根表土壤(RS)次之,距根系较远的土壤(NRS)和根内(HP)最少,即:RP>RS>NRS≥HP;菌株固氮酶活性相差较大(C2H4 112.5～1 147.9 nmol/mL*h),具有较高固氮酶活性的菌株较少(C2H4大于500 nmol/mL*h只有2株);菌株均为革兰氏阴性菌,经鉴定分属Azotobacter(3株)、Pseudomonas(3株)和Azospirillus(2株)3个属.相对于其它生境和植物,高寒地区燕麦根际联合固氮菌种类较为单一.     

高寒地区燕麦根际联合固氮菌研究 Ι固氮菌分离及鉴定

结合气相色谱仪,利用乙炔还原等方法对高寒地区重要饲用植物——燕麦(Avenasativa)根际联合固氮菌进行了分离和鉴定。结果表明,该地区燕麦根际联合固氮菌株较少(8株),菌株分布以根系表面(RP)最多,根表土壤(RS)次之,距根系较远的土壤(NRS)和根内(HP)最少,即:RP>RS>NRS≥HP;菌株固氮酶活性相差较大(C2H4112.5～1147.9nmol/mL·h),具有较高固氮酶活性的菌株较少(C2H4大于500nmol/mL·h只有2株);菌株均为革兰氏阴性菌,经鉴定分属Azotobacter(3株)、Pseudomonas(3株)和Azospirillus(2株)3个属。相对于其它生境和植物,高寒地区燕麦根际联合固氮菌种类较为单一。     

单播草坪匍匐翦股颖溶磷菌筛选及溶磷能力的初步研究

对西安地区单播草坪匍匐翦股颖根际联合固氮菌进行分离的基础上,采用PKO无机磷培养基和蒙金娜有机培养基对匍匐翦股颖根际分离的联合固氮菌(共获得188种分离物)中具有溶磷能力的菌株(占29.3%),通过对菌株溶磷圈大小的测定,最终筛选出溶磷能力较强菌株4株,分离物溶解无机磷D/d值在1.324～3.014之间;而溶解有机磷的能力在1.239～2.156之间.     

单播草坪匍匐翦股颖溶磷菌筛选及溶磷能力的初步研究

对西安地区单播草坪匍匐翦股颖根际联合固氮菌进行分离的基础上,采用PKO无机磷培养基和蒙金娜有机 培养基对匍匐翦股颖根际分离的联合固氮菌(共获得188种分离物)中具有溶磷能力的菌株(占29.3％),通过对菌株溶 磷圈大小的测定,最终筛选出溶磷能力较强菌株4株,分离物溶解无机磷D/d值在1.324~3.014之间;而溶解有机磷的能力 在1.239~2.156之间。     

棕色固氮菌对一年生黑麦草生产的影响

通过对一年生黑麦草分别施以棕色固氮菌、农家肥和未施肥的对比试验,得出棕色固氮菌在增加草产量方面显著优于其他两个处理(P0.01),说明棕色固氮菌对提高一年生黑麦草产量有明显效果。     

禾草内生固氮菌的研究现状及应用前景

植物内生固氮菌是一类重要的固氮微生物资源,其潜在的可开发利用价值越来越受重视。本文综述了禾草内生固氮菌的研究动态、种质资源多样性、侵染途径、定殖方式、作用机理及发展前景,以期为内生固氮菌的进一步开发探究提供参考。     

茶树根际固氮菌研究进展

随着绿色生态农业兴起和发展,茶产业进入绿色、生态、环保的产业升级和转换期。生物固氮是指固氮菌将大气中的氮气还原成氨的过程,在绿色生态农业可持续发展、化肥减量减施、环境生态保护等方面具有重要的意义。茶树根际固氮菌是指分布于茶树根际表面土壤环境中的一类具有固氮能力的微生物,有利于茶树的生长发育、品质提升以及茶树抗逆性增强等作用。从茶树根际固氮菌的多样性、影响因素以及对茶树的作用、研究技术等方面综述茶树根际固氮菌的研究进展,同时探讨了固氮菌在农业可持续发展中的应用前景。     

小麦根际联合固氮菌对燕麦的增产效果

用小麦根际联合固氮菌对燕麦进行拌种的结果表明:每亩鲜草产量比对照增产298kg,提高12.6％,增收13.79元;种子产量增产51kg,提高15.9％,增收33.67元,经济效益明显,宜推广应用。     

犬常见肿瘤流行病学调查及组织病理学诊断

为探讨犬常见肿瘤的发病规律，试验收集哈尔滨地区2016-2017年宠物医院部分犬肿瘤病例71例，采用组织病理学方法对犬肿瘤进行病理学诊断，并对患病动物的品种、性别、年龄、发生部位和饮食情况与肿瘤发生关系进行统计分析。结果显示，71例确诊肿瘤病例中，恶性肿瘤28例，包括鳞状上皮细胞癌3例，基底细胞癌5例，乳腺癌14例，淋巴瘤2例，肾母细胞瘤、精原细胞癌、生殖细胞癌、侵袭性血管黏液瘤各1例；良性肿瘤43例，包括良性乳腺肿瘤15例，纤维瘤10例，平滑肌瘤5例，乳头状瘤和精原细胞瘤各3例，造釉细胞瘤、耵聍腺瘤、脂肪瘤、结节样增生、性索间质细胞瘤、颗粒细胞瘤、肛周腺瘤各1例。上述病例中，乳腺和皮肤是犬肿瘤的高发部位，分别占全部患犬的40.8%和34.0%；患病犬年龄1~16岁不等，平均发病年龄为9.1岁，7岁以后是肿瘤的高发期，中老年犬仍为主要发病群体，但低龄犬发病数量上升；各品种犬均可发生肿瘤，其中杂种犬发病率最高，其次是贵宾犬和京巴犬，且主要为乳腺肿瘤；饮食习惯主要以剩饭剩菜类和肉拌饭类为主，分别占患犬总数的39%和30%；部分肿瘤类型与犬的性别、是否绝育有关，如乳腺肿瘤多发生于未绝育的老年母犬。本研究结果为犬肿瘤的流行病学及诊断提供了参考依据，对犬肿瘤的预防和诊断有一定的借鉴意义。     

MENISCAL OSSICLES IN LARGE NON-DOMESTIC CATS

Radiographs of the stifles of 6 species of 34 large, non-domestic cats were reviewed foremost for the presence of meniscal ossicles and then for the presence of the other potential four sesamoids. The animals in the review included 12 lions, 7 tigers, 7 cougars, 3 leopards, 3 bobcats, and 2 jaguars. Fluoroscopy, arthrography, computed tomography, necropsy, and histology were also used to evaluate the stifles of one tiger after euthanasia. Ossicles were found in the region of the cranial horn of the medial meniscus in most of the lions, tigers, leopards, and jaguars. These ossicles were found in half of the cougars but in none of the bobcats. Among the large, non-domestic cats, meniscal ossicles had been reported previously only in Bengal tigers. The lions, tigers, and leopards having meniscal ossicles appeared to have a lateral but often not a medial fabella of the gastrocnemius muscle, an observation previously unreported. Popliteal sesamoids and patellas were present in all the skeletally mature cats.     

甘南玛曲高寒草甸草地沙化的研究

以甘南玛曲高寒草甸生态系统植物群落样地调查资料为基础,对不同沙化程度植物群落结构及物种多样性特征进行了研究分析。结果表明：随着草地沙化程度的加剧,植物群落多样性指数,均匀度指数及丰富度指数下降,优势度指数增加;禾草地上植物量减少,杂草、莎草地上植物量增加,其中,莎草增加最快。中度沙化阶段是植物群落丰富度、多样性、优势度、地上植物量和均匀度变化的一个转折点,演替早期群落多样性,均匀度及地上总植物量最高,在极度沙化阶段,地上总植物量最低,优势度指数最大。     

新疆伊犁夏牧场铁、铜、锰、锌、硒营养生态环境的研究(Ⅱ)

本试验通过研究伊犁夏牧场不同年龄、不同性别绵羊羊毛与血液中铁、铜、锰、锌、硒5种微量元素的含量及变化规律,为夏季放牧绵羊科学补饲微量元素提供依据。选择在新疆伊犁夏牧场卡拉卓恩(南坡)和唐布拉草地(北坡)1 400~2 999 m垂直带放牧的中国美利奴羊(新疆型)羊毛和血液样品,测定其铁、铜、锰、锌和硒含量,并评估其微量元素的营养生态环境。结果表明,放牧绵羊羊毛铁、铜、锰、锌和硒含量分别为520.70、3.89、30.16、102.64 mg/kg和41.18 μg/kg,其中铜和硒分别低于正常值48.3%和79.7%,而铁高于正常值603.4%;血液中铁、铜、锰、锌和硒含量分别为357.05、4.18、0.25、3.08 mg/L和45.23 μg/L,其中铜、硒分别低于正常值29.9%和73.9%,而铁高于正常值95.5%。羊毛与血液中铁、铜、锰、锌、硒含量均随年龄而增加。不同性别绵羊间血液中锌、硒含量差异明显。     

Advances in therapeutic and managemental approaches of bovine mastitis: a comprehensive review

Mastitis (intramammary inflammation) caused by infectious pathogens is still considered a devastating condition of dairy animals affecting animal welfare as well as economically incurring huge losses to the dairy industry by means of decreased production performance and increased culling rates. Bovine mastitis is the inflammation of the mammary glands/udder of bovines, caused by bacterial pathogens, in most cases. Routine diagnosis is based on clinical and subclinical forms of the disease. This underlines the significance of early and rapid identification/detection of etiological agents at the farm level, for which several diagnostic techniques have been developed. Therapeutic regimens such as antibiotics, immunotherapy, bacteriocins, bacteriophages, antimicrobial peptides, probiotics, stem cell therapy, native secretory factors, nutritional, dry cow and lactation therapy, genetic selection, herbs, and nanoparticle technology-based therapy have been evaluated for their efficacy in the treatment of mastitis. Even though several strategies have been developed over the years for the purpose of managing both clinical and subclinical forms of mastitis, all of them lacked the efficacy to eliminate the associated etiological agent when used as a monotherapy. Further, research has to be directed towards the development of new therapeutic agents/techniques that can both replace conventional techniques and also solve the problem of emerging antibiotic resistance. The objective of the present review is to describe the etiological agents, pathogenesis, and diagnosis in brief along with an extensive discussion on the advances in the treatment and management of mastitis, which would help safeguard the health of dairy animals.     

高原鼠兔洞口区侵蚀过程高山草甸土壤的变化

在西藏那曲高山嵩草草甸,选择高原鼠兔活动区域不同高度土堆和不同深度侵蚀坑,分析表层土壤粒度和养分.结果表明,高原鼠兔掘洞形成洞口土堆,造成草甸土壤发生侵蚀,侵蚀程度随着侵蚀坑深度逐渐增加而减弱,在侵蚀坑深度达到20cm时侵蚀基本停止;在侵蚀过程中,细粒物质减少,砾石含量增加.在强烈侵蚀阶段初期,有机物分解条件改善,土堆表层土壤的有机质、全N、全P、水解N、速效K含量提高,但土壤养分物质在侵蚀作用下迅速流失,土壤有机质、全N、全P、水解N、速效P和速效K含量减少;在侵蚀减缓阶段,养分损失速度减缓,补偿作用逐渐增加;在侵蚀基本停止阶段,土壤表层有机质、全N、水解N和速效K含量明显增加.     

瘤胃厌氧真菌的作用及其分子生物学研究方法

瘤胃厌氧真菌这一特殊的菌群除在瘤胃中发挥重要作用外,其分泌的高活性纤维素酶的应用价值也备受关注,因传统培养的局限性,因此,利用分子生物技术开展的研究逐渐深入。作者主要从瘤胃厌氧真菌的特点和多样性出发,厌氧真菌对结构性碳水化合物、淀粉和蛋白质的降解及在瘤胃生态环境中的作用进行了分析,并对研究瘤胃厌氧真菌的分子生物学方法如内转录间隔区(ITS)、变性梯度凝胶电泳(DGGE)、限制性片段长度多态性(RFLP)、实时荧光定量PCR(Real-time PCR,RT-PCR)和宏基因组学(metagenomics)等进行了阐述,以期为瘤胃厌氧真菌的研究提供参考。     

Ectoparasites: future challenges in a changing world

Ectoparasites are ubiquitous, often highly damaging and in most cases cannot be permanently eradicated; hence, they must usually be managed at a local scale with insecticides or endectocides. However, the growth in resistance, the slow rate of development of new actives, coupled with environmental and health concerns associated with the continued use of some of the existing neurotoxic insecticides, suggest that more sophisticated approaches to their management need to be identified. These approaches need to allow ectoparasite populations to be maintained at acceptable levels, while conserving the compounds that remain available. The development of integrated approaches, in which cascades of management tactics are deployed, with parasiticides available as one component to be used in requisite circumstances, may be the most appropriate route to achieving this aim. An essential element of such an approach is the clear articulation of the purpose of intervention and rational justification of the time-point and manner in which it is attempted. However, for this to be possible, considerably better information is required about the effects of ectoparasite abundance on animal welfare and productivity, in addition to the greater availability of effective alternative control tools. To this end, recent work undertaken at the School of Biological Sciences at the University of Bristol, into the use of biological control agents, off-host trapping and the selective treatment of more highly susceptible individuals or classes of host, is reviewed here.     

家畜免疫去势研究进展

传统的手术去势技术正受到动物福利和规模化标准化畜牧生产需求的挑战,作为手术去势的优势替代方法,免疫去势能够很好地阻滞睾丸发育,控制性行为,避免手术带来的痛苦。免疫去势是采用免疫学方法破坏下丘脑-垂体-性腺轴的激素平衡,通过降低促性腺激素释放激素（GnRH）、黄体生成素（LH）和卵泡刺激素（FSH）的水平,进而使性腺激素水平降低,最终抑制性腺功能,达到去势的目的。免疫去势分为激素免疫去势和基因免疫去势,其靶标经历了下丘脑-垂体-性腺轴自下而上的筛选,依次为睾酮、LH、FSH、GnRH、吻素-1（KISS-1）,其中位于下丘脑-垂体-性腺轴上游的GnRH激素、GnRH和KISS-1基因3种靶标去势效果较好。免疫去势效果及机制的相关研究表明,免疫去势具有改善生产性能、安全和可逆的特点,但其可逆性机制还不清楚。去势导致肾上腺发挥代偿作用,但目前免疫去势的肾上腺代偿研究鲜见报道。文章首先介绍了几种靶标的免疫去势机制,其次对免疫去势的特点和应用进行了讨论,旨在为推动免疫去势技术在动物生产繁殖领域的应用提供理论依据。     

Blood serum characteristics of newborn pigs: comparison of unaffected pigs with pigs belonging to five mortality groups.

The blood serum levels of glucose, hemoglobin, insulin, cortisol, albumin, alpha-fetoprotein, alpha 2-macroglobulin f and s, alpha 2-antitrypsin inhibitor and alpha 1-protease inhibitor were determined at birth in 5 clinically and morphologically identified mortality groups of pigs. These were compared with the levels observed in unaffected, apparently normal newborn unsuckled pigs. The blood serum profile of the pigs in the stillborn intra partum, weak, splayleg and trauma groups, respectively, as well as that of clinically normal splayleg littermates, differed significantly from that of the unaffected pigs. This was especially true for the levels of hemoglobin and the two macroglobulins. The importance of placental insufficiency causing chronic episodes of hypoxia which ultimately lead to a disturbance in organ development in the etiology of the mortality groups is discussed.