Dominance and mating behavior of rams under paddock conditions     

S. El Kaschab  E. Kallweit 《Reproduction in domestic animals》1988,23(4):203-208

Contents A total of 30 ewes in three-sire or four-sire breeding pens were observed continously during daylight for four consecutive days of a synchronised estrus period. A linear dominance hierarchy was observed between the rams which was consistent and stable for each observation period. The highest ranking ram had more mounting encounters and was more aggressive than the subordinate rams. This activity disturbed his ejaculatory mechanism and sometimes resulted in the absence of ejaculation or energetic ejaculation. In the four-sire breeding pens the dominant ram often found it impossible to completely curtail the sexual activity of the subordinate rams. He made 70.9% and 49.0% of the total number of mounts in the three-sire and our-sire breeding pens, respectively. At the beginning of each observation period the highest ranking ram claimed most estrous ewes for his “harem”. The subordinate rams only had an opportunity to mate when several ewes were simultaneously in estrus. The average number of mounts per first copulation per ram was 2.2 (range 1.3–3.1). The time spent from first contact with the ewes until completion of the copulatory act in first copulation varied from 0.2–16.2 min. with an average of 4.0 min., whereas this interval was increased during the second copulation (average = 5.8 min.). Furthermore, the mating behavior of single rams was also observed. Inhalt: Rangordnung und Paarungsverhalten von Schafbocken unter Stallhaltungsbedingungen Es wurden insgesamt 30 Mutterschafe in Zehnergruppen mit 3 bzw. 4 Böcken gleichzeitig in einer Buchte gehalten und wahrend einer Östrusperiode tagsüber beobachtet. Fur die Böcke konnte eine klare Rangordnung erkannt werden, die über alle Beobachtungsperioden unverändert blieb. Der an höchster Stelle stehende Bock vollzog mehr Aufsprungsversuche und war aggressiver als die untergeordneten Böcke. Diese Aktivitäten störten bei ihm wiederholt den Ejakulatonsmechanismus, so daß ein unvollständiger Deckakt bei fehlender Ejakulation die Folge war. Bei gleichzeitiger Anwesenheit von 4 Böcken in einer Gruppe way es für den dominanten Bock häufig unmöglich, die Sexualaktivität der untergeordneten Böcke vollständig zu unterbinden. Auf den dominanten Bock entfielen bei Anwesenheit von 3 Böcken 70,9% aller Auf sprünge, bei der Anwesenheit von 4 Böcken waren dies 49,0%. Zu Beginn einer jeden Beobachtungs-periode versuchte der an höchster Stelle rangierende Bock, die meisten östrischen Mutterschafe für seinen “Harem” zu beanspruchen. Die untergeordneten Böcke hatten nur dann Gelegenheit zu decken, wenn mehrere Mutterschafe gleichzeitig im Östrus waren. Im Durchschnitt betrug die Anzahl der Auf sprünge bei der ersten Belegung pro Bock 2,2 (Schwankungsbreite 1,3 -3, 1). Die erforderliche Zeit fur die erste Paarung uariierte bei einem Mittelwert uon 4,0 Alin. zwischen 0,2 und 16,2 Min.; diese Zeitspanne erhöhte sich allerdings für die zweite Belegung auf durchschnittlich 5,8 Min. Darüber hinaus wurde das Paarungsuerhalten einzelner Böcke ohne die Anwesenheit anderer beobachtet.  相似文献   

Über Verbreitung und Therapie der Begattungsimpotenz bei Schafböcken     

Von P. Mintschev    K. Bakardshiev  V. Shekov 《Reproduction in domestic animals》1972,7(3):116-123

Inhalt Bei Böcken hochproduktiver Schafrassen ist die Begattungsimpotenz, meist infolge Libidomangel, eine weit verbreitete Erscheinung. Nach den vorliegenden, während der Deck- und Besamungsperiode durchgeführten Untersuchungen schwankt die Zahl begattungsimpotenter Böcke in den einzelnen Herden, Zuchtfarmen und Besamungsstationen und innerhalb der verschiedenen Rassen in relativ weiten, von Jahr zu Jahr unterschiedlichen Grenzen. Bei den Böcken der Besamungsstationen wurde ein durchschnittlicher Anteil von 23,7 %, bei den Böcken der LPG von 17,7 % ermittelt. Die Begattungsimpotenz wird ihrer klinischen Form nach in zwei Hauptarten geteilt: 1. Die reversible, d. h. durch Behandlung zu heilende Störung der Funktionen der Geschlechtssphäre. 2. Die nicht aufzuhebende, d. h. permanente Störung dieser Funktionen, wahrscheinlich infolge dystropher Veränderungen in den Zentren und den Leistungsbahnen der Geschlechtssphäre. Bei Behandlungsversuchen an begattungsimpotenten Böcken mit 1%iger, wäβriger Lösung von Morphium hydrochloricum wurde folgendes Resultat erzielt: Von 100 jungen Böcken (ca. 1½ Jahre alt) der verschiedenen Schafrassen zeigten 82% und von 72 älteren Böcken (ca, 2½ Jahre und älter) 56,8 % nach der Behandlung zum ersten Mat Libido, führten den Paarungsakt aus und konnten zur Samengewinnung mit der künstlichen Schelde herangezogen werden. Die Begattungsimpotenz der durch Behandlung geheilten und in der Deckperiode desselben Jahres verwendeten Böcke wiederholte sick in dem jeweils folgenden Jahr bei 18 (22 %) der 82 jungen Böcke und bei 16 (39,1 %) der 41 älteren Böcke. Bei den Maβnahmen zur Einschränkung und Beseitigung der Begattungsimpotenz der Böcke, die besonders in den Stationen und Farmen zur Erzeugung von Elitezuchtmaterial sowie in den Stationen für künstliche Besamung dringend erforderlich sind, muβ die auf breiter biologischer Basis stehende Prophylaxe an erster Stelle stehen. Angezeigt ist hier neben einer Verbesserung der Umwelthedingungen eine strenge Selektion auf Begattungs- und Befruchtungspotenz bzw. Fruchtharkeit bei der Auswahl männlichen und weiblichen Zuchtmaterials. Im Hinblick hierauf sind gründliche Untersuchungen, die die Bedeutung der Erblichkeit und der Umwelt für das Auftreten und die Verbreitung der Begattungsimpotenz der Schafböcke klären, erforderlich. Contents Impotence, mainly due to lack of libido, occurs widely in rams of highly productive breeds of sheep. The number of impotent rams of any breed in an individual flock, breeding farm or AI centre varies relatively widely from year to year. An average of 23.7% of rams in AI centres and 17.7% of LPG rains were found to be affected. Clinically impotence can be divided into two main types 1) reversible, i.e. functional disturbances of the gonads which can be restored by treatment, 2) irreversible and permanent disturbance of these functions, probably due to dystrophic changes in the central nervous centres and in the accessory sexual apparatus. Experimental treatment of impotent rams with a 1% aqueous solution of morphine hydrochloride showed the following results; 82% of 100 young rams (1½ years old) of various breeds, and 56.8% of older rams (2½ years and older) showed libido for the first time after treatment. They also copulated and could be used to collect semen with an artificial vagina. In the rams which had been treated successfully and used during the mating period of the same year, the impotence recurred the following year in 18 (22%) of the 82 young rams and in 16 (39.1%) of the 41 older rams. Prophylaxis on a broad biological basis is of paramount importance among preventive measures to reduce and eliminate impotence, which is urgently necessary in AI centres, breeding stations and farms for the production of high class breeding stock. Selection for mating capacity, fertilization potency and fertility is indicated in the choice of male and female breeding stock, as is an improvement in environmental conditions. Basic experiments are required to clarify the relative importance of heredity and environment in the occurrence and spread of impotence in rams.  相似文献   

Analysis of buoyant density of canine peripheral blood leukocytes with PVP-Silica (Percoll) density gradients     

W A Buurman  P A Vegt  G Groenewegen  C J van der Linden  G M Jeunhomme 《Veterinary immunology and immunopathology》1982,3(6):547-556

Isolation of canine peripheral blood mononuclear cells with a one step centrifugal separation procedure has not been very successful sofar. Significant contamination with polymorphonuclear cells has been reported. An analysis of the buoyant density of canine peripheral blood leukocytes on a self-generating Percoll gradient showed that the buoyant densities of polymorphonuclear cells and lymphocytes are so near that separation with high purity and yield is not possible with the use of a density gradient. Transient changes in buoyant density of polymorphonuclear cells have been observed. In such situations differences in buoyant density between cell types have been observed which permit separation of mononuclear cells from polymorphonuclear cells at a reasonable yield.  相似文献   

The Possibility of Chromosome Classification as Identified by Trypsin-Giemsa Banding Patterns     

Y.-I. Miyake  T. Ishikawa 《Reproduction in domestic animals》1978,13(1):33-37

Inhalt Möglichkeit einer Chromosomenklassifikation durch eine Trypsin-Giemsa-Bänderungstechnik. Es wird eine modifizierte Trypsin-Giemsa-Bandtechnik für Chromosomen beschrieben, die beim Schwein eine deutliche Bänderung zur Chromosomenidentifikation ergibt. Die Bänderung wird erzielt durch eine Verkärzung der Kolchizineinwirkung auf 30 Minuten und eine Behandlung der 3–5 Tage alten Objektträger mit einer 0,1 % Trypsinlösung (Sörensenpuffer pH 6,8) über eine Dauer von 10–20 Minuten bei 4°C und anschlieβender Färbung mit 2 % Giemsalösung (Phosphatpuffer pH 6,8) für 7–10 Minuten. Mit dieser Technik konnten die 18 autosomalen Chromosomen und die beiden Geschlechtschromosomen des Schweines identifiziert werden. Einzelheiten der G-Bandzeichnung eines jeden Chromosoms dieser Spezies werden beschrieben und in einem Karyotypogramm photographisch und schematisch belegt. Das beschriebene Verfahren kann für Zytogenetiker der Human- und Tiermedizin von Bedeutung sein. Contents In the present paper the authors present a modified trypsin-giemsa chromosomal banding technique showing clear banding patterns for the identification of pig chromosomes. The banding patterns were induced by the reduction of colchicine density or trypsin treatment at a critical temperature of 4°C. Identification of 18 pairs of autosomes and a pair of sex-chromosomes of pig were made successfully. Details of the G-banding patterns of each chromosome were described and illustrated both in a karyotypical photograph and in a schematic diagram. The methods may be of importance to veterinary cytogenetics and genetical pathology, as well as to human medicine.  相似文献   

不同重悬细胞法在洗涤过程中对水牛外周血单个核细胞活率的影响     

韩忠燕  张宝红  黄海愉  张为宇  黄维义  钟恒禄 《中国畜牧兽医》2009,36(4):100-102

为了探讨在离心洗涤水牛外周血单个核细胞（peripheral blood mononuclear cell, PBMC）过程中以移液器吹打法和晃动离心管法重悬细胞对其活率的影响。对经密度梯度离心后初步收集到的PBMC,分别用移液器吹打和晃动离心管2种方法重悬细胞,离心洗涤后对细胞活率进行计数。结果发现,移液器吹打法得到的细胞活率为（74.9±2.6）%,而晃动离心管法使细胞活率达到（98.5±0.5）%,差异极显著（P<0.01）。说明在洗涤PBMC时,晃动离心管法重悬细胞能大大提高细胞活率,可为那些对细胞活率要求高的试验提供一个较为有效的方法。  相似文献   

Feline one-way mixed leukocyte reaction     

Mary I. Stiff  Richard G. Olsen 《Veterinary immunology and immunopathology》1984,7(1):1-9

The feline one-way mixed leukocyte reaction (MLR) was accomplished by a microtechnique assay using gradient purified mononuclear leukocytes from the peripheral blood of specific-pathogen-free (SPF) cats. An eight day assay was required with an appropriate serum supplement of rabbit or cat serum and obtainable cell concentrations of 1×10⁵ mononuclear cells per well of each responder and stimulator population. This assay was devised as an $\text{in vitro}$ correlate of cell-mediated immunity and to demonstrate that feline histocompatibility differences can be detected in culture.  相似文献   

The effect of different isolation procedures on canine leucocyte populations and on lectin-induced lymphocyte proliferation     

de Bruin T  de Rooster H  van Bree H  Cox E 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2005,52(9):460-465

Proliferation assays performed on peripheral blood mononuclear cells (PBMC) are commonly used in experimental and clinical immunology. A prerequisite for an in vitro assay is the ability to obtain relatively pure populations of mononuclear cells from whole blood, as contaminating polymorphonuclear cells may affect the proliferation of lymphocytes. Purification of canine leucocytes from whole blood is associated with difficulties in obtaining pure lymphocytes in high yields. The aim of this study was to optimize the lymphocyte purification from canine whole blood in terms of total cell recovery and purity, while not influencing the proliferation capacity of the isolated cells. To acquire optimal isolation of canine lymphocytes several density gradient media of different densities and osmolalities were examined. For optimal phagocyte removal, pre-treatment of whole blood with carbonyl iron/arabic gum and/or adherence to fibrinogen pre-coated polystyrene tissue flasks were examined. Lectin-induced proliferation was used as measurement of cell activity of the obtained cell fractions after the different separation procedures. Canine blood pre-treated with carbonyl iron/arabic gum followed by density gradient centrifugation with medium 'G' (density: 1.079 g/cm(3), osmolality: 256 mOsm) and adherence to pre-coated polystyrene tissue flask obtained the best PBMC cultures with a median lymphocyte purity of 88% and a median yield of recovered lymphocytes of 54%. This culture also resulted in the highest proliferation and subsequently the highest stimulation index upon lectin stimulation.  相似文献   

猪外周血T淋巴细胞增殖反应MTT检测方法的建立   总被引：1，自引：0，他引：1  

赵世云  赵新新  苏华荔  刘贤勇  索勋 《中国畜牧兽医》2010,37(12):35-38

T细胞增殖反应是宿主T细胞识别病原的结果,也是宿主细胞免疫应答的重要指标之一。为了便于检测猪群在病原感染或者疫苗免疫过程中产生的细胞免疫应答,本研究应用MTT法建立了体外检测猪外周血T细胞增殖反应的研究方法。通过密度梯度离心法从外周血分离得到外周血单个核细胞（PBMC）,然后利用单核细胞和淋巴细胞不同的生长特性（贴壁与否）,弃掉贴壁的单核细胞,获得外周血淋巴细胞(PBL)。外周血淋巴细胞的流式分析结果显示,分离获得的PBL中T细胞所占比例达到了80%以上。应用MTT法分析了非特异性刺激物刀豆蛋白A（ConA）的浓度和细胞培养密度对T细胞增殖的影响。结果显示,ConA的工作浓度为5 μg/mL、细胞培养密度为2×106/mL时T细胞的增殖反应最强烈。本研究所建立的猪外周血T细胞增殖反应检测法可以为研究猪针对病原或疫苗的细胞免疫反应提供参考。  相似文献   

Single step purification procedure for the rapid separation of equine leucocytes     

A. D. Sedgwick  T. Morris  B. A. Russell  P. Lees 《Veterinary research communications》1986,10(1):445-452

Percoll gradients have been used to separate relatively pure populations of viable equine polymorphonuclear (PMN) and mononuclear (MN) cells. In preliminary studies, a continuous density gradient of 70% Percoll solution was used to separate two distinct leucocyte-rich bands. After measurement of the density of each band on the continuous gradient, discontinuous Percoll gradients, using 60% and 75% Percoll solutions, were used to provide a rapid means of separating PMN and MN cells. The yield of viable cells per ml of blood was 3.0×10⁶ and 3.2×10⁶ for MN and PMN cells, respectively. Corresponding values for recovery were 45% and 72%. The purity was 94% for PMNs and 99% for MNs.  相似文献   

Evaluation of gonadal macroscopic and microscopic morphometry reveals precocious puberty in Bísaro pig     

Gustavo Paixão  Alexandra Esteves  Nuno Carolino  Maria dos Anjos Pires  Rita Payan-Carreira 《Reproduction in domestic animals》2020,55(12):1706-1713

Bísaro pig (BP), like many other local breeds reared in extensive non-industrial systems, faces many constraints to comply with the EU welfare regulation, particularly regarding the restrictions to surgical castration. In order to adapt an immunocastration protocol to overtake this issue, a puberty timeline is needed. Using gonadal morphometry data from 91 young male BP, this study intended to characterize testicular development, describing the prominent cell types and structures, to ultimately assess the age at puberty in male BP through a mixed prediction model. As expected, the relations between several macro and microscopic parameters and their relation with age were as described within the literature. Post-pubertal animals have larger and heavier gonads, lower Sertoli cell density/tubule, higher Leydig cell density and larger seminiferous tubules. Meiosis was firstly seen in 44-day-old animals, elongated spermatids in 70-day-old animals. Complete spermatogenesis was firstly identified in a 90-day-old animal. Spermatozoa were present in the epididymis of 23 animals, aged from 70 to 240 days old, and in the vas deferens of 14 animals (105 to 240 days old). The prediction model inferred that male Bísaro pigs reach puberty between 14 and 17 weeks (3 and 4 months old) and become sexually capable from 15 to 19 weeks (3.5 and 4.4 months old). These parameters confirm the sexual precocity of this breed.  相似文献   

Enrichment of T lymphocytes from bovine peripheral blood mononuclear cells using an immuno-affinity depletion technique ("panning")     

D L Williams  J L Lo  G F Amborski 《Veterinary immunology and immunopathology》1986,11(2):199-204

A simple and efficient method to enrich bovine T lymphocytes from peripheral blood mononuclear cells (PBMC) by immuno-affinity depletion ("panning") has been developed. The PBMC were initially separated by density gradient centrifugation on Histopaque of density 1.077 g/ml. The T lymphocyte subset was then separated from PBMC by depletion of membrane immunoglobulin (Ig) bearing cells which had an affinity for anti-Ig antibodies bound to polystyrene tissue culture flasks. An average of 95% of the nonadherent "panned" cells were identified as T lymphocytes using a label of peanut agglutinin conjugated with fluorescein isothiocyanate (PNA-FITC). Two percent of the PNA negative cells were Ig bearing cells. The average yield was 50% of the original T lymphocytes found in the PBMC population, and the cell viability as assessed by trypan blue exclusion was greater than 95%. The separation took approximately 2 hours, and the total number of T lymphocytes recovered from 40 ml of blood was in the range of 20-40 X 10(6).  相似文献   

Detection of an Ehrlichia bovis-like Organism in Cultured Buffalo Monocytes     

Sreekumar C  Anandan R  Balasundaram S  John L 《Tropical animal health and production》2000,32(2):67-72

Monocytes from a buffalo were cultured in RPMI 1640 medium following separation of plasma by the erythrocyte sedimentation technique and subsequent separation of mononuclear cells by density gradient centrifugation. Growth of an organism considered to be Ehrlichia bovis was noticed in the cultured monocytes after 10 days. The inclusions were considered to be those of E. bovis from their morphology, staining characteristics and growth characteristics in culture, and by indirect immunofluorescence examination with an anti-E. canis serum. The utility of peripheral blood monocyte cultures opens the possibility of diagnosing the carrier status of ehrlichiosis in animals.  相似文献   

Flow cytometric detection of bovine viral diarrhea virus in peripheral blood leukocytes of persistently infected cattle.   总被引：3，自引：0，他引：3       下载免费PDF全文

P Qvist  B Aasted  B Bloch  A Meyling  L Rnsholt    H Houe 《Canadian journal of veterinary research》1990,54(4):469-472

Flow cytometry was investigated for detection of bovine viral diarrhea virus (BVDV) in peripheral blood mononuclear leukocytes of persistently infected cattle. The mononuclear leukocytes were purified by sedimentation in a gradient of Ficoll-Paque, fixed, permeabilized, and then labelled by indirect immunofluorescence using biotinylated immunoglobulins from a porcine antiserum to BVDV. Flow cytometric analysis of blood samples obtained from persistently infected cattle revealed virus in 3.0-21.0% (mean +/- SD, 11.2% +/- 6.4%) of the mononuclear leukocytes. Fluorescent cells were not observed in controls. Flow cytometric detection of BVDV in blood cells of persistently infected bovines is a rapid and objective technique which does not require cell culture facilities.  相似文献   

Isolation of koala lymphoid cells and their in vitro responses to mitogens.     

R Wilkinson  I Kotlarski  M Barton  P Phillips 《Veterinary immunology and immunopathology》1992,31(1-2):21-33

Baseline parameters have been established for the successful in vitro culture of mononuclear cells from the peripheral blood (PMC) of koalas. To minimise stress-related influences and allow repeated testing of cells from the same animals, most studies were performed using blood samples from captive koalas which had become accustomed to regular handling. Ficoll-Paque density gradient fractionation of whole blood was required to prepare cell suspensions which responded well to the T-lymphocyte mitogens phytohaemagglutinin, concanavalin A and pokeweed mitogen. In contrast, very low or negligible proliferative responses were induced by the B-lymphocyte mitogens lipopolysaccharide, jacalin and protein A, even when purified PMC were cultured with a wide range of concentrations of these molecules. Using the standard approaches established with T-lymphocytes of eutherian animals, it was shown that concanavalin A-stimulated PMC produced an interleukin 2-like growth factor. The significance of these findings is discussed in the context of current knowledge and understanding of similar studies carried out using the lymphoid cells of eutherian and other metatherian animals.  相似文献   

Single step purification procedure for the rapid separation of equine leucocytes     

A D Sedgwick  T Morris  B A Russell  P Lees 《Veterinary research communications》1986,10(6):445-452

Percoll gradients have been used to separate relatively pure populations of viable equine polymorphonuclear (PMN) and mononuclear (MN) cells. In preliminary studies, a continuous density gradient of 70% Percoll solution was used to separate two distinct leucocyte-rich bands. After measurement of the density of each band on the continuous gradient, discontinuous Percoll gradients, using 60% and 75% Percoll solutions, were used to provide a rapid means of separating PMN and MN cells. The yield of viable cells per ml of blood was 3.0 X 10(6) and 3.2 X 10(6) for MN and PMN cells, respectively. Corresponding values for recovery were 45% and 72%. The purity was 94% for PMNs and 99% for MNs.  相似文献   

Isolation of porcine monocyte population: a simple and efficient method     

Christin Berg  Sebastian Wilker  Johann Roider  Alexa Klettner 《Veterinary research communications》2013,37(3):239-241

Monocytes are important mediators of inflammatory processes and are in the focus of immunological studies. While the preparation of human monocytes is widely established, little is published on the isolation of porcine monocytes for experimental studies. The aim of this study is to establish a cost efficient method of preparing and culturing porcine monocytes of considerable purity and reasonable yield. In our method, we combined and modified different protocols of human monocyte preparation. The blood of a single pig is harvested and treated with EDTA to prevent coagulation. Peripheral blood mononuclear cells are obtained by a density gradient centrifugation using a Bicoll gradient and monocytes are harvested by culturing on serum-treated culture flasks, rinsing and tapping. A high yield is obtained by constant cooling of flasks and tubes. The purity of the culture is evaluated by the expression of CD14, using flow cytometry. Using this method, we reached a purity of 92.6 % (+/? 3.06 %). With this procedure, we established a reliable method to prepare and cultivate porcine monocytes which can be performed cost effectively and does not require special equipment.  相似文献   

Isolation of bovine polymorphonuclear leukocytes by density gradient centrifugation   总被引：2，自引：0，他引：2  

W H Chambers  J R Taylor  P H Klesius 《Veterinary immunology and immunopathology》1983,5(2):197-202

A method for the isolation of an enriched population (greater than 95%) of bovine polymorphonuclear leukocytes (PMNs) was developed using density gradient centrifugation. Leukocytes were isolated from peripheral blood by centrifugation in a density gradient medium (Percoll) of specific gravity 1.092. Viability was greater than or equal to 95% and the isolated PMNs were functional in migration inhibition and chemiluminescence assays. This has proved to be a simple effective method for obtaining bovine PMNs and yields cell populations that can be utilized for a variety of measures of PMN function.  相似文献   

东达山高寒草甸8种植物气孔特征沿土壤水分梯度的变化     

张大才  朱玉怀  李双智 《草业学报》2018,27(7):36-46

植物叶片气孔密度和大小具有可塑性,在外界胁迫下而变化,是植物适应环境变化的重要机制。为揭示高寒草甸生境趋向干旱化过程中植物气孔特征的变化规律,选择藏东南东达山高寒草甸的8种优势或常见植物作为研究对象,设置10个土壤水分梯度,分析气孔特征的变化。结果表明,根据植物对土壤水分的依赖程度可划分为4种类型:大花嵩草为沼生型,随土壤干旱程度的增加气孔密度增加、气孔大小减小;鸭跖草、小大黄、矮生嵩草和珠芽蓼为湿生型,气孔密度和大小与土壤含水率之间的关系多呈现为单峰曲线格局;圆穗蓼和线叶嵩草为旱生型,气孔特征随土壤干旱程度增加的变化趋势与沼生型植物几乎相反;高山嵩草气孔特征与土壤含水率之间的相关性不显著,在土壤水分梯度上分布范围广,为广布型。每种植物生长都有适宜的土壤水分条件,过高或过低的土壤含水率都将胁迫植物的生长,因此植物气孔特征与土壤含水率之间的关系呈现多种变化格局。  相似文献   

Separation and identification of bovine lymphocyte populations     

T J Yang  E D Rabinovsky 《Veterinary immunology and immunopathology》1987,14(1):77-84

Various methods for separation of lymphocyte populations have been modified and adapted for use in isolating and identifying bovine lymphocytes. Ficoll diatrizoate (F-D) with a specific density of 1.084 was found to be superior to those with densities of 1.080 and 1.077 which were developed originally for the mouse and human mononuclear cells, respectively. F-D with a density of 1.084 attained a lymphocyte (absolute number) recovery rate of 92% whereas those with densities of 1.080 and 1.077 yielded 81% and 71% recovery rate of lymphocytes, respectively. Subsequent separation of T lymphocytes was achieved best by nylon wool column whereas separation of B lymphocytes was attained best by complement-mediated depletion of T lymphocytes with the T lymphocyte specific monoclonal antibody (MAb), BLT-1. The former yielded 95 +/- 3% T lymphocytes with 47 +/- 9% recovery rate, and the latter gave 96 +/- 3% B lymphocytes with 71 +/- 9% recovery rate. In comparison, direct panning of F-D gradient separated mononuclear cells with goat anti-bovine IgG coated plates yielded 80% B lymphocytes with 31% recovery rate and indirect panning of MAb BLT-1 treated F-D gradient-separated mononuclear cells with goat anti-mouse IgG coated plates yielded 89% T lymphocytes with 35% recovery rate.  相似文献   

Separation of equine bronchopulmonary lavage cells by density gradient centrifugation and expression of procoagulant activity in unpurified cells and cell subpopulations     

G Grünig  C Hulliger  M Hermann  C Winder  R von Fellenberg 《Research in veterinary science》1990,49(1):39-45

Bronchopulmonary lavage was performed in 10 healthy horses and in 39 horses with chronic pulmonary disease. The predominant cell types were macrophages in healthy horses and neutrophils in severely diseased horses. Procoagulant activity (PCA) was detected in all 32 cell-free supernatants examined and in all 49 unpurified cell suspensions. Cells were separated by centrifugation on discontinuous gradients prepared either with Percoll or with Metrizamide. Macrophages were enriched in subpopulations of low density. Neutrophils could not be purified by density gradient centrifugation using either gradient medium. PCAs of cell subpopulations were plotted against their respective macrophage, neutrophil, and lymphocyte content. PCA was positively correlated with macrophage content (P less than 0.001) and negatively correlated with neutrophil (P less than 0.02) and lymphocyte (P less than 0.001) content. Therefore, PCA of equine lung cells most likely originates from macrophages as shown in other species. The density shift of lung neutrophils requires further investigation.  相似文献