Differential feeding success of two paralysis-inducing ticks, Rhipicephalus warburtoni and Ixodes rubicundus on sympatric small mammal species, Elephantulus myurus and Micaelamys namaquensis

Rodents are recognised as important hosts of ixodid ticks and as reservoirs of tick-borne pathogens across the world. Sympatric insectivores are usually inconspicuous and often overlooked as hosts of ticks and reservoirs of disease. Elephant shrews or sengis of the order Macroscelidea are small insectivores that often occur in sympatry with rodents in southern Africa. Sengis are invariably parasitised by large numbers of immature ticks while sympatric rodents are infested with very few. The reason for the difference in tick parasitism rates between these hosts is unknown. While a number of mechanisms are possible, we hypothesised that certain tick species exhibit "true host specificity" and as such would only attach and feed successfully on their preferred host or a very closely related host species. To investigate this, we conducted feeding experiments using two economically important tick species, the brown paralysis tick, Rhipicephalus warburtoni and the Karoo paralysis tick, Ixodes rubicundus and two sympatric small mammal species as potential hosts, the eastern rock sengi, Elephantulus myurus and the Namaqua rock mouse, Micaelamys namaquensis. Ticks attached and fed readily on E. myurus, but did not attach or feed successfully on M. namaquensis suggesting that these ticks exhibit true host specificity. We suggest that a kairomonal cue originating from the odour of E. myurus may stimulate the attachment and feeding of these ticks and that they further possess immunosuppressive mechanisms specific to E. myurus, allowing them to feed on this host species but not on M. namaquensis. This study highlights the importance of small mammalian insectivores as potential hosts of ixodid tick species and hence their potential as reservoirs of tick-borne pathogens.     

Endocrine status and development of porcine testicular tissues in host mice

Clarification of the endocrine status of host mice provides us with basic knowledge with which we can manipulate the growth and function of xenografted testicular tissues. We investigated the hormonal profiles of castrated mice grafted with porcine immature testicular tissues from 30 to 210 or more days after grafting (day 0=castration and grafting). The serum follicle stimulating hormone (FSH) concentrations of the host mice declined (P<0.05) from day 60 compared with those of the castrated, ungrafted mice. The serum inhibin and testosterone levels were higher (P<0.05) than those in the castrated, ungrafted mice from days 30 and 90 days, respectively. The inhibin levels further increased (P<0.05) from day 90, during which time the levels were higher (P<0.05) than those in the intact male mice. In the grafts, formation of lumens occurred in the seminiferous cords on day 90 and spermatozoa appeared in the lumens from day 120. However, spermatogenesis in the grafts did not reach the qualitatively normal levels observed in adult boars. The intensity of the immune reaction to inhibin alpha subunits in the Sertoli cells of the grafts decreased with differentiation of the seminiferous tubules. The present findings indicate that a feedback loop was established between the mouse hypothalamo-pituitary axis and the grafted porcine tissues from 60 days post-grafting. The results also indicate that the serum inhibin levels in the host mice remained high even after the appearance of lumens in the seminiferous tubules of the grafted tissues; this is strikingly different to the situation in normal male animals, in which the serum inhibin levels decline at around the time of tubular differentiation. The lack of efferent ducts in the tubules of the grafted tissues probably caused the accumulation of inhibin to be released into the lumens, resulting in high concentrations of circulating inhibin. These high levels of inhibin may directly affect spermatogenic activity and suppress FSH secretion.     

Fleas of elephant shrews (Mammalia, Macroscelididae) and a new host and locality record for Macroscelidopsylla albertyni De Meillon & Marcus, 1958 (Siphonaptera, Chimaeropsyllidae)

Fleas collected from the elephant shrews Elephantulus edwardii (A. Smith, 1839) in the Western Cape Province, Elephantulus myurus Thomas & Schwann, 1906 in Free State Province, and an Elephantulus of undetermined species in the Eastern Cape Province, South Africa are recorded in this paper. Five flea species were recovered of which Demeillonia granti (Rothschild, 1904) was the most numerous and prevalent. It was followed by Macroscelidopsylla albertyni De Meillon & Marcus, 1958, collected only from E. edwardii. Both this elephant shrew and the locality are new records for M. albertyni. Chiastopsylla octavii (Rothschild, 1904), Listropsylla agrippinae (Rothschild, 1904), and a female flea of the Ctenocephalides felis group were accidental infestations. The sex ratio of D. granti was 0.86 on both male and female elephant shrews, while that of M. albertyni on E. edwardii was 0.83.     

Parasites of domestic and wild animals in South Africa. XVIII. The crowned guinea fowl (Numida meleagris), an important host of immature ixodid ticks

The tick burdens of 10 crowned guinea fowl (Numida meleagris), shot at approximately 3-monthly intervals in the Mountain Zebra National Park, and of 21 crowned guinea fowl from the Andries Vosloo Kudu Reserve, the majority of which were shot at monthly intervals, were determined. No adult ticks were recovered from any of the guinea fowl. The birds in the Mountain Zebra National Park harboured 4 species of ixodid ticks of which Amblyomma marmoreum was the most abundant and most prevalent. Three birds also harboured Hyalomma marginatum turanicum. Six ixodid tick species were present on guinea fowl in the Andries Vosloo Kudu Reserve. Of these Amblyomma hebraeum was the most abundant and all the birds were infested. Most of these birds were also infested with A. marmoreum and Haemaphysalis silacea and some harboured Hyalomma marginatum rufipes. The seasonal abundance of ticks on crowned guinea fowl is discussed.     

Heartwater. The development and life cycle of Cowdria ruminantium in the vertebrate host, ticks and cultured endothelial cells

Various aspects of the development and life cycle of Cowdria ruminantium are discussed. C. ruminantium is transmitted transstadially by certain Amblyomma species. Apparently organisms initially develop in the gut epithelial cells of ticks and subsequent stages of C. ruminantium invade and develop in the salivary gland acini cells of the vector. Stages at which transmission to the final host are attained appear to be coordinated with the feeding cycle of the ticks and the vertebrate host is infected via salivary glands of the tick. In the vertebrate host, ticks and cultured endothelial cells, different morphological forms of C. ruminantium (electron-dense and reticulated forms) are found. Organisms enter cells through a process resembling phagocytosis and reticulated forms of the organisms appear to be the main vegetative stage. In the vertebrate host, organisms proliferate in vascular endothelial cells, neutrophils, macrophages and reticulo-endothelial cells.     

The numbers of bush ticks, Haemaphysalis longicornis, parasitic on grazing cattle before and after the acquisition of host resistance

The numbers of bush ticks, Haemaphysalis longicornis, on Bos taurus steers in south east Queensland was recorded regularly from July 1971 until January 1974. The steers had no prior exposure to the tick. The parasitic tick population was large during the first year, but declined to low levels in the second and third years, apparently as a result of the steers acquiring resistance to tick feeding.     

The germfree murine animal: an important animal model for research on the relationship between gut microbiota and the host

The genomic island 3 (GI-3) shared by Brucella melitensis and Brucella abortus contains 29 genes encoding mostly unknown proteins. Within this island, the open reading frames (ORFs) BAB1_0278 and BAB1_0263 are present, BAB1_0278 encodes a hypothetical protein of 64 amino acids sharing a domain with the GcrA superfamily, whereas the amino acid sequence of BAB1_0263 showed 42% identity with an iron regulated Lsr2 protein. We obtained one deletion mutant for each one of these ORFs present within the B. abortus GI-3 named BA-278 and BA-263, respectively. Both mutants were evaluated with respect to their ability to invade and replicate in nonprofessional and professional phagocytes (HeLa and J774.A1 cells) and their virulence in mice. Both mutants invaded efficiently HeLa and J774. A1 cells, however, 48-h post-infection the BA-278 mutant showed a lower intracellular persistence. The deletion of the ORF BAB1_0278, also affected the persistence of B. abortus in the spleens of mice, unlike to the deletion of the ORF BAB1_0263. These results allow us to conclude that BAB1_0278 ORF contributes to virulence of Brucella, since it is necessary to establish an optimal infectious process.     

The host status of African buffaloes, Syncerus caffer, for Rhipicephalus (Boophilus) decoloratus

The objective of this study was to assess the host status of African buffaloes, Syncerus caffer, for the one-host tick Rhipicephalus (Boophilus) decoloratus. To this end the R. (B.) decoloratus burdens of ten buffaloes examined in three north-eastern KwaZulu-Natal Province (KZN) nature reserves were compared with those of medium-sized to large antelope species in these reserves and in the southern Kruger National Park (KNP), Mpumalanga Province. The R. (B.) decoloratus burdens of the buffaloes were considerably smaller than those of the antelopes in the KNP, but not those in the KZN reserves. The life-stage structure of the R. (B.) decoloratus populations on the buffaloes, in which larvae predominated, was closer to that of this tick on blue wildebeest, Connochaetes taurinus, a tick-resistant animal, than to that on other antelopes. A single buffalo examined in the KNP was not infested with R. (B.) decoloratus, whereas a giraffe, Giraffa camelopardalis, examined at the same locality and time, harboured a small number of ticks. In a nature reserve in Mpumalanga Province adjacent to the KNP, two immobilized buffaloes, from which only adult ticks were collected, were not infested with R. (B.) decoloratus, whereas greater kudus, Tragelaphus strepsiceros, examined during the same time of year in the KNP harboured large numbers of adult ticks of this species. African buffaloes would thus appear to be resistant to infestation with R. (B.) decoloratus, and this resistance is expressed as the prevention of the majority of tick larvae from developing to nymphs.     

The status and need for characterization of Nordic animal genetic resources

ABSTRACT

The Nordic countries are committed to conserving farm animal genetic diversity. National reports on phenotypic and genetic characterization point towards a lack of characterization for many Nordic native breeds. Little to no knowledge on the traits of the animals and their derived products leads to potential remaining untapped. The objective of this study was to provide a quantitative assessment of phenotypic and genetic characterization of Nordic native breeds, through a literature search and obtaining census data. Six species and a total of 85 breeds were included. Studies were classified according to six different categories of characterization. Results showed that a large percentage of the breeds are not characterized at all. Moreover, most breeds have extremely low census sizes. A substantial effort to increase population sizes and document characteristics of Nordic native breeds, to promote conservation and sustainable use, is needed.     

The most important causes for quantitative and qualitative losses during breeding and turnover before slaughtering of farm animals

The present review article deals with the current knowledge on the most important reasons of quantitative and qualitative losses during breeding and turnover before slaughtering of farm animals. At present, the profitability of every economic activity of people is an indispensable necessity. As regards farm animals there are many factors, seemingly banal ones, that determine the final economical effect and satisfaction of such activity. Many essential errors are made by producers as a result of ignorance or not complying with the basic needs of their behaviour. The turnover only deepens these neglects. The most essential limitations of these quantitative and qualitative losses are the proper selection and joining of the animals as well as an exact knowledge and complying with their natural behaviour. Such activity decreases animal stress, improves a proper welfare and consequently increases economical effects considerably.     

广西奶水牛业发展现状与建议

2005年广西存栏杂种母水牛21426头,其中能繁母牛11546头,占存栏母牛54%,产奶牛3214头,奶产量4664吨.2006年底存栏杂种母水牛26443头,同比增长23.4%,其中能繁母牛14574头,占存栏母牛的55%,同比增长26.2%,产奶牛3632头,同比增长13%,奶产量4898吨,同比增长5%.     

水富县蚕桑产业的现状及发展对策

水富县自1992年发展蚕桑以来,曾取得了辉煌的成绩,被确定为云南省蚕桑生产基地县,桑园面积过万亩,养蚕量逐年上升,为全县产业发展和农民增收作出了一定的贡献,但也经历了极其艰难的困境.现在正处在一个是进是退的关键时期,下面就水富县蚕桑产业的现状和发展对策作一些探讨.     

The putative penicillin-binding proteins 1 and 2 are important for viability, growth and cell morphology of Brucella melitensis

The penicillin-binding proteins (PBPs) are enzymes that regulate the assembly of the peptidoglycan layer of the bacterial cell wall. The genome of Brucella melitensis strain 16M possesses seven pbp genes: three in pbp-1 family (designated as 1A, 1B, and 1C); one in pbp-2 family; and three in pbp-6 family (designated as 6A, 6B, and 6C). We investigated the importance of pbp-1 and pbp-2 genes to viability, cell morphology and infectivity of B. melitensis. A recombinant B. melitensis strain (designated 16MDeltapbp1C) was generated by disrupting the pbp-1C of strain 16M by allelic exchange. This strain produced nearly 20% smaller colonies on trypticase soy agar plates, and grew slower in trypticase soy broth compared to the strain 16M. Electron microscopy revealed that strain 16M exhibited native cocco-bacillus morphology, while 16MDeltapbp1C possessed a spherical morphology. Strain 16MDeltapbp1C did not differ from strain 16M in terms of recovery from infected mouse macrophage cell line J774.1, or recovery from spleens of infected BALB/c mice, suggesting that pbp-1C is dispensable for intracellular persistence of B. melitensis. Expression of mRNA of fixR, the gene downstream of pbp-1C was similar between the strains 16M and 16MDeltapbp1C suggesting that disruption of pbp-1C did not induce any polar effects. Multiple attempts to mutate pbp-1A, pbp-1B, or pbp-2 genes failed, most probably because these genes are indispensable for viability of B. melitensis. Our findings suggest that pbp-1C regulates in vitro growth and cell morphology, whereas pbp-1A, pbp-1B, and pbp-2 are essential for viability of B. melitensis.     

我国的笔料毛山羊和笔料毛生产

笔料毛山羊并非一种经人们有意识的经过长期选择和培育所形成的专门化山羊品种．而是一种主要作为肉食用的普通白山羊，笔料毛是其副产品。因而很多白山羊品种都能生产笔料毛，但不同品种的白山羊所产的笔料毛质量差异很大。最好的笔料毛的质量和产区，其分布大体上和湖羊产地相吻合．主要分布在江、浙两省的长江三角洲平原，而尤以江苏为重。这一带气候温和，寒暖适宜，无霜期长，水草丰盛。     

浅析蓬安蚕业的现状与对策

蓬安是司马相如故里,位于川东北丘陵地区,总人口68万,辖1个街道办事处和46个乡镇.这里水源充足,交通便捷,是连接南充至广安、重庆的中心腹地,是南充市蚕桑生产基地县.全县现有市、县蚕桑基地乡镇20个.蚕桑业历来是立县的支柱产业,桑树资源极为丰富,蚕桑基础雄厚,曾创下过年发种10万张,产茧280万kg的历史最高记录,蚕农养蚕收入近4 000万元,约占农副业总收入的25%以上.     

非洲蜂业现状及对我国蜂业发展的启示

非洲蜂业具有养殖方式落后、野生种群数量大、蜜蜂的抗病力强等特点,同时非洲(尤其是南非)蜂业面临着海角蜂对其他亚种蜜蜂寄生的威胁。本文对非洲养蜂业的这些典型特征进行了介绍,并结合我国蜂业发展现状讨论了我国蜂业在可持续发展中面临的两个潜在问题—蜂种遗传背景单一及西方蜜蜂的引入对我国生态的影响。     

非洲蜂业现状及对我国蜂业发展的启示(续)

<正>(续2010年第1期)四、海角蜂灾难东非蜜蜂分布于南非夏季雨季区,海角蜂则仅分布于南非的东、南、西部开普海角海岸。历史上由于地貌的影响,两个亚种地理隔绝,在其分布区之     

我国饲料级磷酸脲现状及发展前景分析

磷酸脲是一种反刍动物矿物质饲料添加剂,能为牲畜提供磷和非蛋白氮两种营养元素。若磷酸脲的生产成本降低,饲料级磷酸脲有一定的发展前景。     

PCR技术在鼠金黄色葡萄球菌检测中的初步研究

根据已公布的金黄色葡萄球菌耐热核酸酶nuc基因的序列 ,设计并合成一对特异性的引物 ,利用PCR技术扩增nuc基因片段。对金黄色葡萄球菌和其他非金黄色葡萄球菌菌株抽提的DNA进行扩增。结果金黄色葡萄球菌PCR产物出现 6 6 8bp的特异性DNA扩增片段 ,而其他非金黄色葡萄球菌未出现扩增片段 ,证实了合成的引物对金黄色葡萄球菌具有特异性。将抽提的金黄色葡萄球菌DNA进行系列稀释 ,测定此PCR体系的敏感性。结果显示 ,该PCR体系能检出 3pg金黄色葡萄球菌DNA ,且从抽提DNA到PCR扩增及电泳结束仅需 4h。因此 ,研究所建立的扩增耐热核酸酶nuc基因检测鼠金黄色葡萄球菌的PCR方法 ,具有快速、可靠、敏感和特异的特点 ,可用于临床样品和金黄色葡萄球菌感染时的检测 ,适合应用于实验大小鼠的监测