布氏锥虫C型凝集素类似蛋白的鉴定

C型凝集素在机体免疫系统中具有重要的作用.为了解布氏锥虫(T.brucei)基因组编码的C型凝集素类似蛋白(CLLPs),本研究在GeneDB数据库中通过软件鉴定了13种T.brucei基因组编码的CLLPs家族基因序列,并分析它们之间的遗传进化关系.同时,采用RT-PCR方法检测了其中3种CLLPs基因在血液阶段(BSF)T.brucei虫体内的转录.利用PCR扩增并在大肠杆菌中对所选3种基因进行表达,以表达的重组蛋白免疫小鼠制备多克隆抗体.实验结果表明,本研究选择的3种CLLPs基因在BSF T.brucei虫体内均能够进行转录;而通过间接免疫荧光检测表明所选的3种CLLPs基因中,只有一种CLLP (Tb5290)在T.brucei的BSF阶段和昆虫阶段(PCF)表达.本研究首次在T.brucei中鉴定了C型凝集素家族的新成员,为进一步了解CLLPs在T.brucei中的生物学功能的研究奠定了基础.     

Effects of supplemental protein sources during the grazing period on performance, ruminal characteristics and blood constituents in early weaned growing Wagyu steer calves

We investigated the effects of grazing and supplemental protein sources during the grazing period on growth performance, ruminal characteristics and blood constituents in 15 growing Wagyu steer calves weaned at 3 months of age. Each animal was allotted one of three treatments: (1) GSBM, soybean meal (SBM) supplemented as a protein source during a grazing period; (2) GCGM, corn gluten meal (CGM) supplemented as a protein source during a grazing period; or (3) NG, no grazing, in which steers were fed hay and GSBM concentrate only. The estimated rumen undegradable protein (RUP) concentration of CGM was higher than that of SBM. High RUP supplementation during the grazing period did not influence feed intake or growth performance. Compared with the NG treatment, the average daily gain in GSBM and GCGM calves was significantly depressed (P < 0.05). Bodyweight/withers height ratio in the NG calves tended to be greater than in the GSBM and GCGM calves. Final paunch girth/heart girth ratio in the GSBM and GCGM calves was significantly greater (P < 0.05) than in the NG calves. Supplementation with CGM did not influence ruminal ammonia nitrogen and blood constituents. These results indicate that CGM supplementation during the grazing period did not enhance the growth of Wagyu calves because the CGM diet probably did not elevate the metabolizable protein supply to the grazing calves above that of the SBM diet in our conditions.     

Marker-assisted selection for forelimb-girdle muscular anomaly of Japanese Black cattle

Forelimb‐girdle muscular anomaly is a hereditary disorder of Japanese Black cattle characterized by tremors and astasia caused by hypoplasia of the forelimb‐girdle muscles. The locus responsible for this disorder has been mapped on a middle region of bovine chromosome 26. In this study, we applied marker‐assisted selection to identify the carriers of this disorder. Four microsatellite markers, DIK4440, BM4505, MOK2602 and IDVGA‐59, linked to the disorder locus were genotyped in 37 unaffected offspring of a carrier sire. Transmission of the mutant or wild‐type allele of the disorder locus of the sire to the 37 offspring was determined by examining the haplotypes of these markers. The results showed that nine and 18 of the 37 animals possessed the paternally transmitted mutant and wild‐type alleles, respectively, and therefore, the nine animals with the mutant allele were identified as carriers. We concluded that the marker‐assisted selection using these four markers can be applied for the identification of the carriers of forelimb‐girdle muscular anomaly of Japanese Black cattle.     

Migration of albacore, Thunnus alalunga, in the North Pacific Ocean in relation to large oceanic phenomena

On the basis of Japanese long-line fishery data during 1970–1988, anticlockwise migration routes of albacore in the North Pacific are newly proposed. The annual migration route for mature albacore is described as a closed ellipse with a centre at 20°N and 170°E, and is wider in El Niño years than non-El Niño years associated with an appearance of a cold-water region in the central and south-western North Pacific. Immature albacore also have an anticlockwise migration route in winter which extends from 25°N to 35°N and from 130°E to 180°E, when the Kuroshio has a relatively straight path. However, the migration does not persist when the Kuroshio takes a large meander path.     

Effects of high potassium chloride supplementation on water intake, urine volume and nitrogen balance in mice

Sixteen ICR male mice were assigned to a control diet group or a KCl diet group in metabolic cages to clarify the effects of KCl supplementation on water intake, urine volume and N balance, and 5% of KCl was supplemented in KCl diets for 4 or 8 weeks. Bodyweight of KCl supplemented mice was significantly higher than that of control mice from 24 to 28 days after treatment. Feed intake, water intake and urine volume of KCl supplemented mice were significantly higher than those of control mice, and the increased water intake and urine volume in KCl supplemented mice were 4.49 and 4.15 g, respectively. Urinary N, K and Cl excretion were significantly higher in KCl supplemented mice. Although N retention was not significantly different between control and KCl supplemented mice, N retention in KCl supplemented mice tended to be lower. Serum creatinine concentration at 8 weeks after treatment was lower in KCl supplemented mice. Histological alteration using hematoxylin-eosin and Sirius red staining was not found in the kidney of each mouse at 4 and 8 weeks after treatment. These results suggest that high KCl supplementation increases water intake, urine volume and urinary N excretion in mice.     

Interdecadal variations of plankton biomass and physical environment in the North Pacific

In the central and western subarctic Pacific, zooplankton biomass and chlorophyll concentrations during the mid 1960s to mid 1970s were a few times higher than in the preceding and following decades, corresponding to higher values of the atmospheric Northern Hemisphere Zonal Index (NHZI). In the Alaskan Gyre, however, it was reported that biomass of zooplankton and nekton doubled after the atmospheric regime shift in the mid 1970s. In the subtropical North Pacific, chlorophyll a concentration decreased drastically after 1980, although a decrease of zooplankton biomass was clearly seen only in the northern part of the subtropical gyre. Chlorophyll concentration in the central subarctic Pacific and zooplankton biomass in the Oyashio have been decreasing since the early 1980s. Additionally, chlorophyll concentration in the western subarctic Pacific and eastern Bering Sea, and zooplankton biomass in the central subarctic Pacific and eastern Bering Sea have also been decreasing since the late 1980s. In these regime-shift situations, there is a general tendency for intensification of wind speed or de-stratification to cause plankton biomass to decrease in regions where the upper mixed layer is deep, such as the western subarctic and north-western subtropical water, whereas in relatively stratified areas, such as in the eastern subarctic and south-western subtropical water, the effect is an increase of plankton biomass.