Parasite survey of the eastern oyster Crassostrea virginica in coastal lagoons of the southern Gulf of Mexico

A parasitological study of the eastern oyster Crassostrea virginica from 11 coastal lagoons in the southern Gulf of Mexico in dry and rainy seasons between late 1999 and early 2001 revealed the presence of 36 bacterial, 2 protozoan (Nematopsis prytherchi and Perkinsus marinus), and 4 helminth species (Urastoma cyprinae, Proctoeces maculatus, a Bucephalus sp., and a Tylocephalum sp.). The prevalence and mean abundances for the protozoa and helminths varied widely between locations but were generally below 50%. Nematopsis prytherchi and the Tylocephalum sp. were the most prevalent species (values were above 60% in most locations). Perkinsus marinus was present in oysters of eight of the coastal lagoons and had low prevalence (<30%) in almost all samples. All identified protozoa and helminths are widely distributed in the Gulf of Mexico and are common oyster parasites. Only P. marinus and the Bucephalus sp. were associated with damage to host tissues. In addition to these parasites, Rickettsia-like bacteria were found in the digestive gland and gills and viral gametocytic hypertrophy inclusions in the gonads by histological examination.     

Influence of endosperm vitreousness and kernel moisture at harvest on site and extent of digestion of high-moisture corn by feedlot steers

Six ruminally and duodenally cannulated Angus-Jersey crossbred steers (450 kg of BW) were used in a 6 x 6 Latin square to evaluate the effect of kernel vitreousness and moisture on intake and digestibility of high-moisture corn. Arranged in a 2 x 3 factorial, diets included a floury (FLO) or a vitreous (VIT) endosperm corn hybrid harvested at 28.1% (DRY), 31.2% (MID), or 35.7% (WET) kernel moisture content. Diet DM consisted of 88.25% high-moisture corn, 6% chopped alfalfa hay, 2% corn gluten meal, 0.75% urea, and 3% supplement. Supplement was included to ensure that the diets contained a minimum (DM basis) of 0.6% Ca, 0.6% K, 0.2% S, 33 mg/kg of monensin, and 11 mg/kg of tylosin. Geometric mean diameter of lyophilized high-moisture corn tended to be less (P = 0.06) for VIT than for FLO, and the calculated particle surface area was 15.8% greater (P = 0.03). An interaction of vitreousness with the quadratic effect of moisture was noted (P < 0.001), such that fraction a and effective degradation for starch tended to be greater for the vitreous hybrid at the least and greatest moisture content but lower for the vitreous hybrid at the intermediate moisture content. Intake and ruminal disappearance of DM, OM, and starch were not influenced by vitreousness or moisture, with ruminal starch disappearance averaging 90.9%. Intestinal starch digestion measured as a percentage of starch entering the intestines averaged 91% and was greater (P < 0.05) for VIT than FLO corn. Averaged across moisture levels, total tract starch digestibility was greater (P < 0.003) for VIT than FLO. Compared with FLO kernels, VIT kernels appeared to be more brittle and therefore shattered more readily when rolled, particularly at the driest kernel moisture level. Furthermore, increased surface area of smaller particles may have been responsible for the greater starch utilization from VIT corn. In contrast with the results from other in situ and in vivo trials with dry-rolled corn grain, in which the starch from vitreous hybrids was less rapidly or completely digested, hybrids with more vitreous starch, when fed as high-moisture corn, had greater total tract starch digestibility, primarily due to greater postruminal starch digestion.     

Direct desaturation of free myristic acid by hen liver microsomal Delta9-desaturase without prior activation to myristoyl-CoA derivative

Direct desaturation of free myristic acid by hen liver microsomal Delta(9)-desaturase without prior activation to myristoyl-CoA by the addition of adenosine triphosphate (ATP) and CoA was observed when the incubation medium was mixed at mixing speeds of >250 rpm in the presence of fatty acid-binding proteins (FABP). Desaturation was linear with time and proportional to the microsomal protein concentration. Desaturation was maximal at pH 7.9. The greatest desaturation rate was observed at a mixing speed of 500 rpm in the presence of FABP. Desaturation decreased at mixing speeds of >500 rpm. Data suggest that when myristic acid is bound to FABP in the form of protein-monomer complexes, its activation to the CoA derivative is not necessary for it to be desaturated by the Delta(9)-desaturase when using mixing rates of >250 rpm. Myristic acid-FABP complexes serve as substrates for the Delta(9)-desaturase at mixing rates of >250 rpm. Desaturation was reduced by bovine serum albumin and alpha-bromohexadecanoate, and no desaturation was observed in the absence of FABP. These findings suggest that FABP may regulate the accessibility of fatty acids in the desaturation reaction to the active site of the desaturase rather than just protect the membrane-bound desaturase from the cytotoxic effect of free fatty acids.     

基于多年田间实验的尿素和控释尿素肥料对稻田甲烷排放的影响研究

A four-year(2008–2011) field study was implemented in a major rice-growing region of China to better understand the effect of urea and controlled release fertilier(CRF, thermoplastic resin-coated urea in this study) on CH4 emission from paddy fields. Over the four years, the average CH4 emission during the rice growing seasons was 76.9, 65.8 and 64.9 kg CH4ha-1in treatments CK(zero N), U(urea) and C(CRF), respectively. Urea and CRF significantly reduced CH4 emission by 14.4% and 15.6%, and increased average rice grain yield by 25.8% and 19.7%(P 0.05), respectively, compared with treatment CK. Flooding duration would affect CRF's effect on CH4 emission from paddy fields. Under normal aeration conditions, CH4 emission tended to be 3.9%–15.2% lower in treatment C than in treatment U from 2009 to 2011, while it tended to be 4.2% higher under delayed aeration conditions in 2008. The findings suggest that mid-season aeration(MSA) starting on D30(30 days after rice transplanting), just like the local practice, would optimize the CRF's effect on CH4 emission from rice fields in China. Over the four years, average rice yield did not differ between treatments U and C, and tended to be 5% lower in treatment C than in treatment U.     

Profile of trans fatty acids (FAs) including trans polyunsaturated FAs in representative fast food samples

The content of trans fat in foods is most commonly determined by summing the levels of individual trans fatty acids (FAs), analyzed as FA methyl esters (FAME) by gas chromatography. Current Official Methods of the American Oil Chemists' Society (AOCS) enable quantitation of total trans fat in foods but were not designed for the determination of transFA isomeric compositions. In the present study, the content of trans fat in 32 representative fast food samples ranged from 0.1 to 3.1 g per serving, as determined according to AOCS Official Method Ce 1j-07. Further analysis of FAME using the 200 m SLB-IL111 ionic liquid column yielded quantitative results of total, trans, saturated, and cis unsaturated fat that were comparable to those of Method Ce 1j-07 and also allowed for the complementary determination of individual trans 18:1, trans 18:2, and trans 18:3 FA isomeric compositions under conditions suitable for routine sample analysis.     

Use of transcriptome sequencing to explore the effect of CSRP3 on chicken myoblasts

The mechanisms that regulate the specificity and maintenance of chicken muscle fiber types remain largely unknown. In mammals, CSRP3 has been shown to play a vital role in the maintenance of typical muscle structure and function. This study investigated the role that CSRP3 plays in chicken skeletal muscle. First, the antibody against chicken CSRP3 protein was prepared, and the expression levels of the mRNA and protein of the CSRP3 gene in four chicken skeletal muscles with different myofiber com...     

营养对种蛋孵化率的影响

人们对营养与家禽种蛋的胚胎发育和成活率的关系进行了较多的研究。为了提高种蛋的孵化率,维持种母鸡良好的营养状况是至关重要的。营养素过少或过多都会影响孵化率。那么,哪些营养素会影响种蛋的孵化率呢? 一.维生素类 1.维生素 研究表明,种鸡饲料中缺乏维生素A,不仅会降低种蛋孵化率,而且还会降低产蛋率。然而,若饲料中维生素A含量超过10 000国际单位/千克,也会使初期的胚胎死亡率增加。缺乏维生素A的胚胎症状为位置异常(malpasition)和循环系统发育不全。 2.生物素 维持胚胎的正常发育和孵化需要生物素。缺乏生物素种蛋在孵化第1周到第3周增加胚胎的死亡。为了提高种蛋的生物素含量,在饲料中应该添加生物素或向种蛋注射生物素。饲料中添加生物素的效果,老龄鸡比低龄鸡更为明显。     

Geometric manipulation of trapped ions for quantum computation

We propose an experimentally feasible scheme to achieve quantum computation based solely on geometric manipulations of a quantum system. The desired geometric operations are obtained by driving the quantum system to undergo appropriate adiabatic cyclic evolutions. Our implementation of the all-geometric quantum computation is based on laser manipulation of a set of trapped ions. An all-geometric approach, apart from its fundamental interest, offers a possible method for robust quantum computation.     

蛋白质水平对水貂皮毛生长和品质的影响

本文探讨交替饲喂不同含量的蛋白质饲料对水貂皮毛生长和品质的影响。试验选用母水貂,在妊