Formation of a Reservoir of Sperm in the Oviduct   总被引：2，自引：0，他引：2  

SS Suarez 《Reproduction in domestic animals》2002,37(3):140-143

A reservoir of sperm in the initial segment of the oviduct has been found in several species of domestic and laboratory mammals. Evidently, the reservoir serves to ensure successful fertilization by providing the appropriate number of sperm in the appropriate physiological state for fertilizing oocytes soon after they enter the oviduct. Recent evidence indicates that sperm are trapped in the reservoir by binding to specific carbohydrate moieties on the surface of the mucosal epithelium of the oviduct. A bovine seminal plasma protein has been identified that associates with sperm and confers on them the capacity to bind to the carbohydrate moiety.  相似文献   

Morphological diversity among accessions of Pelargonium sidoides DC. in the Eastern Cape, South Africa     

F. B. Lewu  D. S. Grierson  A. J. Afolayan 《Genetic Resources and Crop Evolution》2007,54(1):1-6

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Phosphatase activity, microbial phosphorus, and fine root growth in forest soils in the Sierra de Gata, western central Spain     

Knut Schneider  Maria-Belen Turrion  Pauline F. Grierson  Juan F. Gallardo 《Biology and Fertility of Soils》2001,34(3):151-155

Acid phosphatase activity (APA), labile P fractions and fine root growth were studied in an oak (Quercus pyrenaica Willd.) forest in the Sierra de Gata, in western central Spain. Soils in the region are acid and rich in organic matter, with low levels of extractable inorganic P but with a high proportion of organic P. In such soils, the activity of phosphatase enzymes is likely to be important for the control of P mineralization and P cycling and, consequently, can affect the availability of P for plant uptake. The biomass of fine roots was about 25-fold that of leaf litter, demonstrating a high allocation of C resources to the root system in order to compensate for a low availability of soil nutrients. The study compared plots fertilized with triple superphosphate (100 kg P ha^-1) to control (unfertilized) plots. Fertilizer application had no significant effect on APA and fine root density; however, there were significant differences in available and microbial P. Spatial and seasonal variations in the APA were related to plant root density and biotic demand. Seasonal differences in the APA may also be the consequence of changes in the amount of hydrolysable organic substrates at different times of the year.  相似文献   

The Influence of Co-Suppressing Tomato 1-Aminocyclopropane-1-Carboxylic Acid Oxidase Ⅰ on the Expression of Fruit Ripening-Related and Pathogenesis-Related Protein Genes     

Zong-li HU Ph D  Xu-qing CHEN  Guo-ping CHEN  Li-juan LÜ  Grierson Donald 《中国农业科学(英文版)》2007,6(4):406-413

The purpose of this study is to explore the influence of co-suppressing tomato ACC oxidase Ⅰ on the expression of fruit ripening-related and pathogenesis-related protein genes, and on the biosynthesis of endogenous ethylene and storage ability of fruits. Specific fragments of several fruit ripening-related and pathogenesis-related protein genes from tomato （Lycopersicon esculentum） were cloned, such as the l-aminocyclopropane-1-carboxylic acid oxidase 1 gene （LeAC01）, 1- aminocyclopropane-l-carboxylic acid oxidase 3 gene （LeAC03）, EIN3-binding F-box 1 gene （LeEBF1）, pathogenesis-related protein 1 gene （LePR1）, pathogenesis-related protein 5 gene （LePR5）, and pathogenesis-related protein osmotin precursor gene （LeNP24） by PCR or RT-PCR. Then these specific DNA fragments were used as probes to hybridize with the total RNAs extracted from the wild type tomato Ailsa Craig （AC＋＋） and the LeAC01 co-suppression tomatoes （V1187 and T4B）, respectively. At the same time, ethylene production measurement and storage experiment of tomato fruits were carded out. The hybridization results indicated that the expression of fruit ripening-related genes such as LeACO3 and LeEBF1, and pathogenesis-related protein genes such as LePR1, LePR5, and LeNP24, were reduced sharply, and the ethylene production in the fruits, wounded leaves decreased and the storage time of ripening fruits was prolonged, when the expression of LeACO1 gene in the transgenic tomato was suppressed. In the co-suppression tomatoes, the expression of fruit ripening-related and pathogenesis-related protein genes were restrained at different degrees, the biosynthesis of endogenous ethylene decreased and the storage ability of tomato fruits increased.  相似文献   

Serological evidence for the presence of Leptospira interrogans serovar bratislava in Australian pigs     

RJ RICHAPPEL  WA ELLIS†  B ADLER‡  L AMON  BD MILLAR§  SS ZHU  RW PRIM§ 《Australian veterinary journal》1992,69(5):119-120

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Genome sequence analysis of 10 Dutch porcine circovirus type 2 (PCV-2) isolates from a PMWS case-control study     

Grierson SS  King DP  Wellenberg GJ  Banks M 《Research in veterinary science》2004,77(3):265-268

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Estimating the level of disease risk and biosecurity on commercial poultry farms in New Zealand     

SS Greening  K Mulqueen  TG Rawdon  NP French  MC Gates 《New Zealand veterinary journal》2020,68(5):261-271

ABSTRACT

Aims: To collect baseline data on the contact risk pathways and biosecurity practices of commercial poultry farms in New Zealand, investigate the relationship between the farm-level disease contact risks and biosecurity practices, and identify important poultry health concerns of producers.

Methods: A cross-sectional survey of all registered New Zealand commercial poultry operations was conducted in 2016 collecting information on farm demographics, biosecurity practices, and contact risk pathways. Survey responses were used to generate an unweighted subjective disease risk score based on eight risk criteria and a subjective biosecurity score based on the frequency with which producers reported implementing seven biosecurity measures. Producer opinions towards poultry health issues were also determined.

Results: Responses to the survey response were obtained from 120/414 (29.0%) producers, including 57/157 (36.3%) broiler, 33/169 (19.5%) layer, 24/55 (44%) breeder, and 6/32 (19%) other poultry production types. Median disease risk scores differed between production types (p?<?0.001) and were lowest for breeder enterprises. The greatest risk for layer and broiler enterprises was from the potential movement of employees between sheds, and for breeder enterprises was the on- and off-farm movement of goods and services. Median biosecurity scores also differed between production types (p?<?0.001), and were highest for breeder and broiler enterprises. Across all sectors there was no statistical correlation between biosecurity scores and disease risk scores. Producers showed a high level of concern over effectively managing biosecurity measures.

Conclusions: The uptake of biosecurity measures in the commercial poultry farms surveyed was highly variable, with some having very low scores despite significant potential disease contact risks. This may be related to the low prevalence or absence of many important infectious poultry diseases in New Zealand leading farmers to believe there is a limited need to maintain good biosecurity as well as farmer uncertainty around the efficacy of different biosecurity measures. Further research is needed to understand barriers towards biosecurity adoption including evaluating the cost-effectiveness of biosecurity interventions.  相似文献   

ACC合成酶和ACC氧化酶基因家族在番茄乙烯过表达突变体Epinastics果实中的差别表达(英文)     

应铁进  曾广文  BarryCS  GriersonD 《浙江大学学报(农业与生命科学版)》1999,(5)

利用 Ｎｏｒｔｈｅｒｎ 杂交和核酸保护分析（ＲＰＡ）检测了番茄ＡＣＣ 合成酶（ＡＣＳ）和 ＡＣＣ氧化酶（ＡＣＯ）基因家族在番茄突变体Ｅｐｉｎａｓｔｉｃｓ （Ｅｐｉ）果实中的表达特性,同时测定了Ｅｐｉ果实自动催化乙烯合成系统的特性⒚ＥＰＩ等位基因的突变诱导了ＬＥＡＣＳ２ 和ＬＥＡＣＯ１ 两个基因的过表达,这是Ｅｐｉ果实的乙烯过表达的主要成因⒚ＥＰＩ突变同时显著抑制了ＬＥＡＣＳ４ 和 ＬＥＡＣＯ３ 的表达强度⒚这些结果初步鉴别了这两个基因家族在番茄果实上表达的各个成员的转录调节途径⒚同时表明,番茄单基因乙烯反应突变体是研究ＡＣＳ和ＡＣＯ基因家族各成员转录调节特性的一种有用工具⒚  相似文献   

Uterine Progesterone Receptor and Leukaemia Inhibitory Factor mRNA Expression in Canine Pregnancy     

S Schäfer-Somi  D Klein  HB Beceriklisoy  S Sabitzer  SS Ay  AR Agaoglu  I Kücükaslan  D Kaya  OA Aksoy  S Aslan 《Reproduction in domestic animals》2009,44(S2):109-114

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Impacts of increased fire frequency and aridity on eucalypt forest structure,biomass and composition in southwest Australia     

Burak K. Pekin  Matthias M. Boer  Craig Macfarlane  Pauline F. Grierson 《Forest Ecology and Management》2009

Water stress and fire disturbance can directly impact stand structure, biomass and composition by causing mortality and influencing competitive interactions among trees. However, open eucalypt forests of southwest Australia are highly resilient to fire and drought and may respond differently to increased fire frequency and aridity than forests dominated by non-eucalypt species. We measured the variation in stem density, basal area, stand biomass, sapwood area, leaf area and litterfall across 16 mixed jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) forest stands along an aridity gradient in southwest Australia that had variable fire histories. Fire frequency was defined as the total number of fires over a ∼30-year period and aridity as the ratio of potential evapotranspiration to annual precipitation. Total stand biomass and sapwood area were predicted from diameter at breast height of individual jarrah and marri trees using allometric equations. Leaf area was estimated using digital cover photography. More arid and frequently burnt stands had higher stem density, especially of smaller trees, which were mainly jarrah. Overall, both standing biomass and leaf area decreased at more arid sites, while sapwood area was largely unaffected by aridity, suggesting that these stands respond to increased water limitation by decreasing their leaf area relative to their sapwood area. Biomass of marri was reduced at more arid and, to a lesser extent, at more frequently burnt stands. However, total stand biomass (jarrah and marri) and leaf area index did not vary with fire frequency, suggesting that less marri biomass (due to slower growth rates, higher mortality or less recruitment) was compensated by an increase in the density of jarrah trees (regeneration). We conclude that increased fire and drought shift tree species composition towards more fire-resistant species and result in denser stands of smaller trees. In contrast, total stand biomass declines with increasing aridity, but has no association with fire frequency.  相似文献