良好的种蛋贮存有助于获得更多的雏鸡

种蛋的孵化率很大程度取决于种鸡群的繁殖力,但是种蛋的贮存也是一个主要决定因素（图1）。防止出现胚胎死亡是种蛋贮存的首要任务,而且这取决于许多影响因素。     

Dogs with heart diseases causing turbulent high-velocity blood flow have changes in platelet function and von Willebrand factor multimer distribution

The purpose of this prospective study was to investigate platelet function using in vitro tests based on both high and low shear rates and von Willebrand factor (vWf) multimeric composition in dogs with cardiac disease and turbulent high-velocity blood flow. Client-owned asymptomatic, untreated dogs were divided into 4 groups: 14 Cavalier King Charles Spaniels (Cavaliers) with mitral valve prolapse (MVP) and no or minimal mitral regurgitation (MR), 17 Cavaliers with MVP and moderate to severe MR, 14 control dogs, and 10 dogs with subaortic stenosis (SAS). Clinical examinations and echocardiography were performed in all dogs. PFA100 closure times (the ability of platelets to occlude a hole in a membrane at high shear rates), platelet activation markers (plasma thromboxane B2 concentration, platelet surface P-selectin expression), platelet aggregation (in whole blood and platelet-rich plasma with 3 different agonists), and vWf multimers were analyzed. Cavaliers with moderate to severe MR and dogs with SAS had longer closure times and a lower percentage of the largest vWf multimers than did controls. Maximal aggregation responses were unchanged in dogs with SAS but enhanced in Cavaliers with MVP (regardless of MR status) compared with control dogs. No significant difference in platelet activation markers was found among groups. The data suggest that a form of platelet dysfunction detected at high shear rates was present in dogs with MR and SAS, possibly associated with a qualitative vWf defect. Aggregation results suggest increased platelet reactivity in Cavaliers, but the platelets did not appear to circulate in a preactivated state in either disease.     

Perfused non-pregnant swine uteri: a model for evaluating transport mechanisms to the side bearing the dominant follicle in humans

Adequate uterine contractility and periovulatory peristalsis, interpreted as "rapid sperm transport" to the side bearing the dominant follicle, may be a precondition for successful reproduction in humans. Estrogen and progesterone fluctuate characteristically during the menstrual cycle, and their source is the dominant follicle and corpus luteum. The question is, how is the direction to the left or right side of transport mechanisms influenced? An extracorporeal perfusion model of the swine uterus was used that maintained the uterus in a functional condition and that was suitable for the study of physiological questions. The effects of side-dependent estrogen, progesterone, and estrogen plus progesterone perfusion on oxytocin-induced uterine peristalsis were assessed using two intrauterine microcatheters placed in each horn of the swine uterus. Estrogen perfusion was associated with an increase in intrauterine pressure (IUP) in a dose-dependent manner only in the estrogen-perfused horn of the swine uterus. There was a significant difference between the IUP increase measured in the estrogen-perfused horn and that in the non estrogen-perfused horn of the swine uterus. Progesterone perfusion showed no effect in general. Furthermore, progesterone antagonized the estrogen effects. This study demonstrates that side-dependent estrogen perfusion resulted in side-dependent contractility in the swine uterus perfusion system used. These observations show that estrogen stimulates uterine contractility in the estrogen-perfused uterine horn and that estrogens may be the "trigger" for the transport mechanisms to the side bearing the dominant follicle during the periovulatory phase through their locally increased concentration and distribution via the utero-ovarian counter-current system in humans.     

A transgenic RNAi approach for developing tomato plants immune to Pepino mosaic virus

RNA interference (RNAi) or gene silencing is a natural defence response of plants to invading viruses. Here, we applied this approach against pepino mosaic virus (PepMV) isolates in their natural host, tomato. PepMV isolates differ in their genetic sequences, the severity of the disease they induce, and their worldwide distribution. PepMV causes heavy crop losses, mainly due to impaired tomato fruit quality. Resistant varieties are not yet available, despite many years of resistance breeding efforts within the tomato seed industry. To generate broad resistance to PepMV strains, conserved sequences from three different strains of PepMV (US1, LP, and CH2) were synthesized as a single insert and cloned in a hairpin configuration into a binary vector, which was used to transform tomato plants. Transgenic tomato lines that expressed a high level of transgene-siRNA exhibited immunity to PepMV strains, including a new Israeli isolate. This immunity was maintained even after graft inoculation, in which a transgenic scion was grafted onto nontransgenic infected rootstocks. However, an immune transgenic rootstock was unable to induce resistance in a nontransformed scion. These results provide the first example of engineered immunity to diverse PepMV strains in transgenic tomato based on gene silencing.     

Circulating concentrations of insulin-like growth factor-1 in dogs with naturally occurring mitral regurgitation

Insulin-like growth factor-1 (IGF-1), which mediates most effects of growth hormone, has effects on cardiac mass and function, and plays an important role in the regulation of vascular tone. In humans, an inverse relationship between degree of heart failure (HF) and circulating IGF-1 concentrations has been found in several studies. In dogs with HF, few studies have focused on IGF-1. We examined circulating IGF-1 concentrations in dogs with mitral regurgitation (MR) caused by myxomatous mitral valve disease. Study 1 included 88 Cavalier King Charles Spaniels (CKCSs) with a broad range of asymptomatic MR (median serum IGF-1: 76.7 microg/L; 25-75 percentile, 59.8-104.9 microg/L). As expected, standard body weight and percentage under- or overweight correlated directly with IGF-1. MR (assessed in 4 different ways) did not correlate with IGF-1. In study 2, 28 dogs with severe MR and stable, treated congestive HF had similar serum IGF-1 concentrations (median, 100.8 g/L; 25-75 percentile, 74.9-156.5 microg/L) as 11 control dogs (79.6 microg/L; 25-75 percentile, 64.1-187.4 microg/L; P = .84). In study 3, the plasma IGF-1 concentration of 15 untreated CKCSs with severe MR was 16.4 +/- 24.2 microg/L lower (P = .02) at the examination when decompensated HF had developed (80.8 +/- 30.9 microg/L) than at a visit 1-12 months earlier (97.2 +/- 39.8 microg/L), possibly in part due to an altered state of nutrition. The studies document that circulating IGF-1 concentrations are not altered before development of congestive HF in dogs with naturally occurring MR, but decrease by approximately 20% with the development of untreated HE In treated HF, circulating IGF-1 concentrations apparently return to within the reference range.     

Transformation of benzoxazinones and derivatives and microbial activity in the test environment of soil ecotoxicological tests on Poecilus cupreus and Folsomia candida

Benzoxazinones, such as 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), and benzoxazolinones, such as 6-methoxy-2-benzoxazolinone (MBOA) and 2-benzoxazolinone (BOA), are biologically active secondary metabolites found in cereals. Because these compounds could be exploited as part of a strategy for reducing the use of synthetic pesticides, ecotoxicological tests were performed recently. In this paper, the transformation of the compounds in the test environment of the ecotoxicological tests was studied. DIMBOA was degraded and partly transformed to MBOA during the period of ecotoxicological testing of the compounds. During testing of MBOA on Poecilus cupreus test media the analysis showed that at the initial concentrations of 2 and 10 mg kg(-1) no MBOA was left after 45 days of testing, but the metabolite 2-amino-phenoxazin-3-one (AMPO) was formed. During testing of BOA on both Folsomia candida and Poecilus cupreus the more biologically active compound 2-amino-phenoxazin-3-one (APO) was formed. Thus, the ecotoxicological test results on MBOA and BOA were partly due to the microbial transformation of the compounds during the time of testing.