A scanning electron microscopic study of the liver of the monkey Macaca speciosa

Summary The bile canalicular network of the monkey was studied by fracturing fixed liver tissue and examination by scanning electron microscopy. Bile canaliculi do not differ remarkably from those described in other species. Their course and luminal diameter vary, depending on their position in the liver lobule. In one specimen the continuity of a canaliculus with a terminal bile ductule (canal of Hering) is presented. Several constrictions occur in this part of the ductular lumen. The interlobular bile duct wall shows two kinds of niches. A single cilium arises from a primary niche. The walls of secondary niches contain numerous primary niches. Simple columnar epithelium lines the common bile duct, the main pancreatic duct and the gallbladder. A common feature is the presence of microplicae on their lateral cell surfaces.

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Zusammenfassung Das Netzwerk der Gallekanälchen beim Affen wird durch Brechen von fixiertem Lebergewebe sichtbar. Strukturen der Portalfelder und der extrahepatischen Gänge werden durch Schneiden von Gewebe dargestellt. DieGallekanälchenunterscheidensichnichtwesentlich von den bei anderen Spezies beschriebenen. Ihr unterschiedlicher Verlauf und Lumendurchmesser hängen von ihrer intralobulären Lage ab. Die Kontinuität eines Gallekanälchens mit einem Ductulus (Heringscher Kanal) wird in einem Fall dargestellt. Im ductulären Lumen kommen mehrere Konstriktionen vor. Die Wand der interlobulären Gallengänge weist zwei Arten von Nischen auf. Eine Einzelzilie kommt aus den primären Nischen. Sekundäre Nischen bestehen aus mehreren primären Nischen. Einschichtiges hochprismatisches Epithel kleidet den Ductus choledochus, den Ductus pancreaticus und die Gallenblase aus. Ein gemeinsames Merkmal ihrer lateralen Zelloberflächen sind Mikroplicae.

     

Elevation of aminopeptidase activity in Biomphalaria glabrata (Mollusca) parasitized by Echinostoma lindoense (Trematoda)

Comparisons of the levels of aminopeptidase activity in the hemocytes and serum of Biomphalaria glabrata at 20 and 30 days postexposure to irradiated Echinostoma lindoense miracidia with enzyme levels in control snails have revealed that there are significant elevations in the serum of snails at both time periods postexposure. Furthermore, there is a significantly higher level of aminopeptidase activity in the serum of snails at 30 days than at 20 days postexposure. Although the biologic function of the elevated levels of serum aminopeptidase in sensitized snails remains uncertain, it is possible that this lysosomal enzyme may degrade the surface proteins of secondarily introduced parasites and thus act as a form of acquired humoral immunity.     

Further studies on bilitranslocase,a plasma membrane protein involved in hepatic organic anion uptake

Bilitranslocase, a plasma membrane protein involved in bilirubin and other organic anion uptake by the liver, exhibits a high molecular weight (170 000) when isolated in the presence of deoxycholate. This value is decreased to approx. 100 000 if deoxycholate is not included in the isolation medium. Both preparations can be resolved into two kinds of subunit, α and β, of 37 000 and 35 500, respectively, by reduction with 2-mercaptoethanol and addition of sodium dodecyl sulfate. Under these conditions the two subunits are still capable of high-affinity sulfobromophthalein binding and, despite the presence of the detergent, may be isolated by preparative polyacrylamide gel electrophoresis still associated with the dye. It may be suggested that the physiological subunit composition of bilitranslocase is α₂-β.     

Effect of N-ethylmaleimide on leucine transport in chang liver cells. I. Stimulatory effect on Na+-independent transport at low concentrations of leucine

Pretreatment of Chang liver cells with $\text{N-}\text{ethylmaleimide}$ (0.5 or 1 mM) stimulated Na⁺-independent uptake of leucine at low concentrations (?1 mM). The stimulatory effect of $\text{N-}\text{ethylmaleimide}$ on the uptake of leucine measured in Na⁺-replete medium was completely blocked by the addition of $\text{b-2-}\text{aminobicyclo}\text{[2,2,1]}\text{heptane}\text{-2-}\text{carboxylate}$ (5 mM), which shows that the L system participates in the stimulation. The Na⁺-dependent uptake of glycine was depressed by $\text{N-}\text{ethylmaleimide}$ pretreatment. The stimulation of the Na⁺-independent component of leucine uptake continued for at least 30 min after $\text{N-}\text{ethylmaleimide}$ treatment, while the inhibition of glycine uptake was progressive with time and the Na⁺-dependent uptake of leucine became depressed later, after the treatment. It has been demonstrated that treatment of cells with $\text{N-}\text{ethylmaleimide}$ is capable of increasing the Na⁺-independent influx of leucine and at the same time slightly decreasing the efflux of it. These results suggest that $\text{N-}\text{ethylmaleimide}$ attacks the Na⁺-independent system of amino acid transport at the reactive SH groups(s) of relevant protein(s) in favor of specific activation of that system in this cell.     

开启防御之门: 植物抗病小体

NLR蛋白是存在于植物和动物中的一个免疫受体大家族, 具有核苷酸结合域并富含亮氨酸重复序列。植物NLR通过识别病原菌特异效应子开启免疫信号转导。第1个植物NLR抗性蛋白于25年前克隆, 但其激活机制仍不清楚, 至今仍未获得一个完整的NLR蛋白结构。最近, 柴继杰、周俭民和王宏伟实验室合作解析了第一个植物完整NLR ZAR1激活前后的结构, 研究成果以两篇论文形式发表在“科学”杂志上, 填补了NLR介导的免疫信号转导研究领域的空白。该文简要总结了相关研究进展, 讨论了NLR免疫信号转导研究领域尚需解决的问题。     

Short-term energy deficit causes net accumulation of linoleoyl-enriched triacylglycerols in rat liver

Energy depletion by reduced food intake over 4 days resulted in a 73% reduction in total rat liver triacylglycerols (TG). In liver TG of energy-depleted rats, dilinoleoyl oleoyl glycerol (OLL) and trilinoleoyl glycerol (LLL)) were quantitatively increased by 85% and 147%, respectively. The net increase in linoleoyl-enriched species could be quantitatively accounted for by the release of linoleate from monolinoleoyl species and its subsequent reacylation into dilinoleoyl species and trilinolein during energy depletion. Hence while palmitate, oleate and some linoleate are being hydrolyzed, presumably for oxidation some linoleate is retained and contributes to the remodelling of hepatic triacylglycerols during energy deficit.     

草鱼免疫应答的初步研究

研究了草鱼在不同水温条件下受抗原刺激后其中和抗体的变化。15℃培养条件下中和抗体上升缓慢,9周内滴度低于1:8;20℃时,3周后抗体可上升到1:256,最高达1:5270,而在25℃时,1周中和抗体即达到1:570,最高可达1:20000以上。并探索了从草鱼血清中提纯抗体的条件,研究其抗体的特性。草鱼血清中的抗体为大分子蛋白,容易解离为抗原性相同,分子量近似于人IgG的较小分子,含有较多的二硫键,具有类似IgM的某些特性。     

天然保肝药研究进展

本文综述了天然保肝药的筛选方法,活性成分的化学结构,以及临床应用.