Ultrastructure and histochemistry,of the stomach of Asplanchna sieboldi

Stomach cells of female Asplanchna sieboldi are specialized for absorption and intracellular digestion of nutrients. Evidence is presented to show that electron-opaque colloidal substances, present in the medium and within digestive vacuoles of the prey (Paramecium), are taken up by the stomach cells at the apical cell membrane and sequestered within food vacuoles which contain hydrolases working in both the acid and alkaline pH range. The stomach cells are also implicated in the absorption of molecules below the resolving power of the electron microscope. In rotifers possessing a complete digestive tract, this task is presumed to be handled by the intestine.     

Effects of prostaglandin E2 and D2 on gastric somatostatin and gastrin secretion

The effects of PGE2 and PGD2 on gastric somatostatin and gastrin releases were investigated using the isolated perfused rat stomach. In the presence of 5.5 mM glucose, the infusion of PGE2 elicited a significant augmentation in somatostatin release, but suppressed gastrin secretion from the perfusate. On the other hand, PGD2 did not affect somatostatin release, although the gastrin secretion decreased significantly, the same as after PGE2 infusion. These results suggest that PGE2 and PGD2 may be important in the regulation of gastric endocrine function, but that PGD2 does not affect gastric somatostatin secretion.     

Efficient use of lactose for the lac promotercontrolled overexpression of the main antigenic protein of the foot and mouth disease virus in Escherichia coli under fed-batch fermentation conditions

Abstract: Derivatives of the lac promoter (tac, pac, rac) belong to the strongest bacterial promoters which are frequently used for the induced overexpression of foreign genes in Escherichia coli . However, their use in fermentation processes is strongly restricted because of the high cost of the inducer iso-propyl-β-D-thiogalactopyranoside (IPTG). The aim of this work was to investigate the possibility of using lac-derived promoters in high cell density processes resulting in a high yield of the induced recombinant protein if glucose is the main carbon and energy source. Lactose is tested as inducer of the main antigenic coat protein (VP1) of the foot and mouth disease (FMD) virus in a T7-RNA polymerase expression system. It was shown that lactose is able to induce the expression of the recombinant gene to an amount of the VP1 protein corresponding to 20% of the total cell protein.     

Neurobiological mechanisms of the meridian and the propagation of needle feeling along the meridian pathway

The present experiments attempt to find the meridian phenomenon and how the needle feeling propagates along the given meridian channels. The neurobiological mechanisms of the meridian were studied with neuroelectrical recording from the motor neurons and CB-HRP retrograde histochemistry technique in both rats and cats. The results demonstrated that most, but not all, of alpha motor neurons supplying a muscle group of a given meridian were selectively activated by afferent inputs originating not only from homonymous or heterogeneous, but synergistic muscle, but also from the skin nerve overlying the muscle group of the homonymous meridian. However, the afferent inputs from the heterogeneous meridian have very weak or no effect. On the other hand, the labeled motor neurons supplying a given meridian muscles form a discrete longitudinal column with a definite bound in the lateral ventral horn. There are oriented dendro-dendristes projections between the labeled motor neurons.The characteristics of both sel     

Enzymes of the tricarboxylic acid cycle in Obeliscoides cuniculi (Nematoda; Trichostrongylidae) during parasitic development

The specific activities of the enzymes of the tricarboxylic acid cycle; citrate synthase, aconitase, isocitrate dehydrogenase, succinate dehydrogenase, fumarase, and malate dehydrogenase, were determined in early fifth-stage, young and mature adult Obeliscoides cuniculi, the rabbit stomach worm. ∝-Ketoglutarate dehydrogenase activity could not be determined in any fraction. Fumarate reductase activity was found only in the mitochondrial fraction while all other enzymes, including an NADP-dependent malic enzyme were localized in the cytoplasm. Glutamate dehydrogenase, acid and alkaline phosphatase activities were also recorded. High levels of those enzymes acting in the “reversed” direction, i.e. MDH and fumarase relative to the enzymes of the “forward” direction, i.e. citrate synthase, aconitase and isocitrate dehydrogenase suggests that under anaerobic conditions a modified tricarboxylic acid cycle can operate. Some variations in specific activities were apparent as the worms matured but no qualitative differences were observed.     

Stomach capacity as a directing factor in prey size selection of three-spined stickleback

Three-spined stickleback consumed prey of one size until the stomach was full whereafter similar-sized prey were rejected, but smaller prey were consumed. This evidence leads to the prediction of a shift in prey size preference as a result of the constraint imposed by remaining stomach capacity.     

PLS-ANN判别分析自体荧光光谱识别胃癌

本文对58例胃癌病人离体标本的癌浆膜和正常浆膜进行以308nm为激发光的自体荧光光谱检测,采用多因素分析法进行光谱信息提取,以识别胃癌。研究表明偏最小二乘法结合神经网络法（简称PLS—ANN）进行判别分析,诊断胃癌的灵敏度为86％,特异度为100％,准确率为93％,有望成为手术中快速识别胃癌在胃壁的浸润范围的有效方法。     

Stable-isotope analyses reveal the importance of seagrass beds as feeding areas for juveniles of the speckled worm eel Myrophis punctatus (Teleostei: Ophichthidae) in Florida

The feeding habits and habitats of the speckled worm eel Myrophis punctatus were studied on the mangrove edge of the Indian River Lagoon (IRL, Florida) using gut-content and stable-isotope analyses of carbon (δ(13) C) and nitrogen (δ(15) N). Four taxa were identified through analyses of gut contents, and the index of relative importance suggested that amphipods, microphytobenthos and annelids are the most important food sources in the fish's diet. To assess the feeding habits of the fish after their recruitment to the IRL, these food sources were collected from mangroves and nearby seagrass beds for isotope analyses. Stable isotopes constituted a powerful tool for discriminating fish prey items from mangroves (mean ± s.d.δ(13) C = -20·5 ± 0·6‰) and those from seagrass beds (mean ± s.d.δ(13) C = -16·9 ± 0·6‰), thus providing good evidence of food source origins. The 56 M. punctatus collected [10·0 < total length (L(T) ) < 16·2 cm] had average isotopic signatures of δ(13) C = -16·7 ± 0·2‰ and δ(15) N = 8·2 ± 0·1‰. A significant depletion in (13) C was observed for larger juveniles (15·0 < L(T) < 16·2 cm), suggesting that they found a portion of their food in mangroves. Estimation of the trophic level from stable isotopes (T(Liso)) was similar among different size groups of juvenile fish (T(Liso) = 3·2-3·5); therefore, M. punctatus was considered a secondary consumer, which is consistent with its zoobenthic diet. The concentration-dependent mixing Stable Isotope Analysis in R (SIAR) model revealed the importance of food sources from seagrass beds as carbon sources for all the fish collected, with a significant increase in mangrove prey contributions, such as annelids, in the diet of larger juveniles. This study highlights the importance of seagrass beds as feeding habitats for juveniles of M. punctatus after their recruitment to coastal waters.     

经血管灌流生长抑素对大鼠离体胃运动的抑制作用

采用血管灌流大鼠离体胃模型,探讨生长抑素对胃运动的影响。结果表明：（１）生长抑素能明显抑制胃窦自发和胃动素兴奋的胃运动;（２）生长抑素可抑制离体胃内源性胃泌素释放;（３）抗生长抑素血清和前列腺素合成酶抑制剂消炎痛可阻断生长抑素对胃窦运动的抑制作用。上述结果提示：生长抑素的抑制作用除通过直接作用于生长抑素受体外,还可能通过胃窦局部前列腺素介导来抑制胃的运动。     

Polymorphisms of 5,10-methylenetetralydrofolate reductase (MTHFR), fruit and vegetable intake, and the risk of stomach cancer

Stomach cancer is a serious public health problem in China. 5,10-Methylenetetralydrofolate reductase (MTHFR) may be involved in both DNA methylation and DNA synthesis. Folate deficiency is associated with cancer risk that may be modulated by a genetic variation in the MTHFR gene in folate metabolism. The main goal of this study was to evaluate the association between polymorphisms of the MTHFR gene and the risk of stomach cancer. This study also explored the modification effects of fruit and vegetable intake (one of the main constituents is folate) on the risk of this disease. A population-based case-control study was conducted in Taixing, China, consisting of 206 newly diagnosed cases with primary stomach cancer and 415 healthy population controls. Polymorphisms of MTHFR C677T and A1298C were assayed by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) techniques. The data were analysed using the logistic regression model. No obvious association between the MTHFR A1298C polymorphism and the risk of stomach cancer was observed in this study. The frequencies of 677 C/C, C/T, and T/T were 34.5, 50.9, and 14.6%, respectively, in controls. The frequency of the MTHFR 677 wild homozygotic genotype was 25.8% in cases, which was lower than that in controls (34.5%). The adjusted odds ratio (OR) for the MTHFR 677 any T genotype was 2.05 (95% confidence interval (CI), 1.26-3.34) when compared with the C/C genotype. In the low fruit and vegetable intake group an increasing trend was observed with the T allele exposure, p=0.0056. The adjusted ORs were 1.68 (95% CI = 0.86-3.29) for the C/T genotype and 3.58 (95% CI = 1.46-8.75) for the T/T genotype, respectively. The MTHFR 677 any T genotype was associated with an increased risk of primary stomach cancer among the Chinese population. Folate deficiency might modify the MTHFR gene polymorphism and influence the risk of stomach cancer.