连接与切断处理对土壤氮素资源异质环境中结缕草主匍匐茎的影响效应

通过实验检验了克隆植物结缕草在异质生境条件下的生理整合作用。结缕草被栽植于4种类型的“生境”内(它们的总体土壤氮素资源水平呈现梯度变化),并同时对匍匐茎的节间实施连接与切断2种处理。实验结果表明,呈连接状态的结缕草克隆的平均复合节数量、平均匍匐茎长度和生物量在各个生境类型间并未表现出明显的差异。但主匍匐茎实施切断处理后的结缕草克隆的上述各项指标均显著减小。生长于贫瘠土壤斑块上的复合节平均根系生物量和根/茎比均高于肥沃土壤斑块。这一特征与其它典型的克隆植物明显不同。结缕草克隆在保持连接的情况下,土壤氮素对节间长度和比节间长度的伸长生长以及分蘖的形成具有促进作用。实验过程中的节间切断处理抑制了节间的进一步伸长但提高了比节间长度。保持结缕草克隆整合并尽量避免严重干扰显得十分重要,特别是在结缕草早期生长阶段。     

A simple and efficient method for extraction of PCR-amplifiable DNA from chicken eggshells

Recently, we reported a method for discriminating a Japanese brand of chicken, the Hinai-jidori. As an application of this method for discriminating Hinai-jidori eggs, we here report an efficient method for extracting maternal DNA from eggshells. Eggshell powder was completely decalcified with EDTA solution, and then DNA was isolated by conventional phenol-chloroform extraction and ethanol precipitation. The efficiency of DNA recovery from eggshells was 50-fold higher than that of a previously reported method. The recovered DNA could be used for PCR, and 10 markers for identifying the Hinai-jidori chicken were detected. The genotypes of the Hinai-jidori exactly matched those of the Hinai-dori breed. Using this method, Hinai-jidori and Hinai-dori eggs could be distinguished from the eggs of Rhode Island Reds. This is the first report of a technique that can be used to discriminate the eggs of Hinai-jidori from those of other chickens, and it can also be utilized to validate the labeling of Hinai-jidori eggs in the market.     

Effects of 5'-uridylic acid feeding on postprandial plasma concentrations of metabolites and metabolic hormones in pre-weaning goats

5'-Uridylic acid (UMP), which is present at high concentrations in cow's colostrum, has been shown to cause a reduction in increased plasma levels of insulin and glucose after ingestion of milk replacer in pre-weaning calves. However, the precise mechanisms of UMP action have not been investigated, and its action has not been investigated in other pre-weaning ruminants. In order to demonstrate whether UMP causes changes in postprandial metabolic and hormonal parameters in pre-weaning goats, 11 Saanen kids were given milk replacer (twice a day) without ( n  = 5) or with ( n  = 6) UMP (1 g for each meal, 2 g/day for each head) for 14 days. Analysis of blood samples taken in the morning of day 14 demonstrated that the feeding of milk replacer with UMP abolished the significant changes in postprandial plasma glucose, NEFA, GH and insulin concentrations induced by feeding of milk replacer alone, and demonstrated a tendency to increase IGF-I levels. However, there was no significant difference between the two groups at any sampling time. We conclude that UMP feeding with milk replacer showed a tendency to blunt the postprandial changes in levels of some plasma metabolites and hormones that are induced by replacer alone in pre-weaning goats.     

Twenty-eight new microsatellite loci in chicken and their cross-species amplification in Japanese quail and helmeted guinea fowl

Twenty‐eight original chicken microsatellite markers were isolated and characterized to determine their utility as cross‐reactive markers for comparative genetic mapping in the order Galliformes. Primer pairs were typed in 12 unrelated chickens and also tested on Japanese quail and helmeted guinea fowl deoxyribonucleic acid (DNA). Polymorphism was observed in 23 (82.1%) of the markers and the average number of alleles per locus was 2.9 while the mean heterozygosity was 0.19. Eleven (39.3%) of the chicken markers cross‐reacted with Japanese quail DNA and 2 (7.1%) with helmeted guinea fowl DNA. The cross‐reactive markers described would serve as useful resources for comparative genetic mapping in poultry species belonging to the order Galliformes.     

Reduced differentiation of intestinal epithelial cells in wasting marmoset syndrome

Wasting marmoset syndrome (WMS) is a serious disease in captive common marmoset (Callithrix jacchus) colonies. Because of the high mortality rates, elucidation of the underlying mechanisms is essential. In this study, we compared the histopathology, the number of each epithelial cell in the jejunum and colon, and the expression patterns of some molecular markers between healthy and WMS-affected marmosets. Atrophy of villi in the jejunum and mononuclear cell infiltration in the lamina propria were observed in the intestinal tract of WMS-affected marmosets. Although the numbers of transient amplifying cells and tuft cells were increased, the number of goblet cells was obviously decreased in the jejunum and colon of WMS-affected marmosets compared to healthy marmosets. In addition, the number of enterocytes in the jejunum was decreased in WMS animals. There was no apparent difference in the numbers of stem cells, enteroendocrine cells, or Paneth cells. The expression of β-catenin and Tcf7l2 was increased in WMS, and the co-existence of β-catenin and Tcf7l2/Cyclin D1 was observed around the crypts in WMS-affected marmosets. These findings suggest that cell proliferation continues, but cell differentiation is halted in the intestinal tract due to the enhanced β-catenin/Tcf7l2/Cyclin D1signaling pathway in WMS, which results in malfunction of the villus and mucosa.     

Denaturation mode of carp myofibrils when affected by temperature and salt concentration

ABSTRACT: Heating temperatures of 30–40°C and KCl concentrations of 0.1–0.5 M altered the denaturation mode of carp myofibrils. In 0.1 M KCl medium, heating temperature affected the denaturation of rod more significantly than of subfragment-1 (S-1), and a slow decrease in solubility at 30°C was accompanied by a slow denaturation of rod. KCl concentration at heating altered the denaturation mode differently at 30°C and 40°C. Increased KCl concentrations for heating reduced the rod denaturation rate at 40°C, but it was increased at 30°C. At concentrations above 0.3*Τ*M KCl, the denaturation rate for rod became identical to that for S-1 at both temperatures. Upon heating of chymotryptic digest of myofibrils, S-1 denaturation was similarly detected as in intact myofibrils, whereas practically no rod denaturation was detected. Thus, it was concluded that myosin structure connecting S-1 and rod has an important role in the denaturation process.     

Gene expression and hormonal regulation of adiponectin and its receptors in bovine mammary gland and mammary epithelial cells

Although the functions of adiponectin, a differentiated adipocyte‐derived hormone, in regulating glucose and fatty acid metabolism are regulated by two subtypes of adiponectin receptors (AdipoRs; AdipoR1 and AdipoR2), those in ruminants remain unclear. Therefore we examined the messenger RNA (mRNA) expression levels of adiponectin and its receptors in various bovine tissues and mammary glands among different lactation stages, and the effects of lactogenic hormones (insulin, dexamethasone and prolactin) and growth hormone (GH) on mRNA expression of the AdipoRs in cultured bovine mammary epithelial cells (BMEC). AdipoRs mRNAs were widely expressed in various bovine tissues, but adiponectin mRNA expression was significantly higher in adipose tissue than in other tissues. In the mammary gland, although adiponectin mRNA expression was significantly decreased at lactation, AdipoR1 mRNA expression was significantly higher at peak lactation than at the dry‐off stage. In BMEC, lactogenic hormones and GH upregulated AdipoR2 mRNA expression but did not change that of AdipoR1. In conclusion, adiponectin and its receptor mRNA were expressed in various bovine tissues and the adiponectin mRNA level was decreased during lactation. These results suggest that adiponectin and its receptors ware changed in mammary glands by lactation and that AdipoRs mRNA expression was regulated by different pathways in BMEC.