The effect of analogues of chymostatin on lysosomal and non-lysosomal components of protein degradation in isolated hepatocytes

Of the proteinase inhibitors derived from Streptomyces spp., chymostatin is the most effective inhibitor of non-lysosomal proteolysis. As part of a systematic study of the structural features of the chymostatin molecule that are responsible for this inhibitory activity, a series of fifteen di- and tripeptide analogues of chymostatin were tested for their ability to suppress protein degradation in isolated primary hepatocytes. Protein degradation was assessed in two ways: by the release of radiolabel from proteins prelabelled in vivo (to which both lysosomal and non-lysosomal processes contribute) and by the rate of inactivation of tyrosine aminotransferase, a process that is exclusively non-lysosomal. All inhibitors were relatively non-toxic and did not affect the intracellular ATP levels, although some suppression of gluconeogenesis was observed in the presence of leupeptin, chymostatin or the analogues. Tripeptide phenylalanine aldehydes or semicarbazones were at least as effective as chymostatin in reducing protein degradation, whereas peptide alcohols were relatively ineffective. Replacement of the basic capreomycidine moiety in chymostatin with an arginine residue improved the inhibitory activity but equally, substitution of the arginine residue with an uncharged norleucine residue was without significant effect. The structural features that are optimal for inhibition of chymotrypsin or other serine proteinases (previously defined) are not as critical for inhibition of protein degradation in vivo.     

世居及移居高原青少年最大有氧能力的特征

本文报道海拔３４１７ｍ和４２８０ｍ地区世居藏族和移居汉族青少年运动状态下心肺功能的对比研究。结果显示：３４１７ｍ和４２８０ｍ世居藏族的最大氧耗量、无氧阈值及最大心输出量都明显大于汉族,血氧饱和度（Ｓａｏ２）随运动负荷的增加而降低。海拔３４１７ｍ藏、汉族的△Ｓａｏ２分别为７．４６％和１０．０３％,４２８０ｍ处为８．５７％和１３．７５％,最大心率随海拔升高而下降。研究提示,藏族青少年有较高的最大有氧能力,反映了他们对低氧环境的适应优势。     

A new monoclonal antibody (3D3) generated with human respiratory mucins and directed against Lewis determinants

We have prepared a monoclonal antibody (MAb), 3D3, raised againstpurified human respiratory mucins. This antibody recognizedmucins and proteolytically derived glycopeptides. The epitoperecognized by the antibody was destroyed by -L-fucosidase, indicatingthat it was present on the carbohydrate moieties. Structuralspecificity was determined by adsorption on a variety of synthetic,insolubilized oligosaccharides. Several lines of evidence indicatethat the 3D3 MAb reacted strongly with the Lewis (Le^b) antigen,but also recognized Le^a and Le^y determinants. This antibodymight be useful to study mucin secretion. human bronchial mucins Lewis b     

The phylogeny of the ant tribe Formicini (Hymenoptera: Formicidae) with the description of a new genus

Abstract. The holarctic ant tribe Formicini is revised, the new genus Bajcaridris described, and possible phylogenetic relationships are discussed. The subgenus Iberoformica is synonymized with Formica. A synopsis, diagnosis and keys to the genera are provided.     

Alterations of Neuromuscular Function after the World's Most Challenging Mountain Ultra-Marathon

We investigated the physiological consequences of the most challenging mountain ultra-marathon (MUM) in the world: a 330-km trail run with 24000 m of positive and negative elevation change. Neuromuscular fatigue (NMF) was assessed before (Pre-), during (Mid-) and after (Post-) the MUM in experienced ultra-marathon runners (n = 15; finish time  = 122.43 hours ±17.21 hours) and in Pre- and Post- in a control group with a similar level of sleep deprivation (n = 8). Blood markers of muscle inflammation and damage were analyzed at Pre- and Post-. Mean ± SD maximal voluntary contraction force declined significantly at Mid- (−13±17% and −10±16%, P<0.05 for knee extensor, KE, and plantar flexor muscles, PF, respectively), and further decreased at Post- (−24±13% and −26±19%, P<0.01) with alteration of the central activation ratio (−24±24% and −28±34% between Pre- and Post-, P<0.05) in runners whereas these parameters did not change in the control group. Peripheral NMF markers such as 100 Hz doublet (KE: −18±18% and PF: −20±15%, P<0.01) and peak twitch (KE: −33±12%, P<0.001 and PF: −19±14%, P<0.01) were also altered in runners but not in controls. Post-MUM blood concentrations of creatine kinase (3719±3045 Ul·¹), lactate dehydrogenase (1145±511 UI·L⁻¹), C-Reactive Protein (13.1±7.5 mg·L⁻¹) and myoglobin (449.3±338.2 µg·L⁻¹) were higher (P<0.001) than at Pre- in runners but not in controls. Our findings revealed less neuromuscular fatigue, muscle damage and inflammation than in shorter MUMs. In conclusion, paradoxically, such extreme exercise seems to induce a relative muscle preservation process due likely to a protective anticipatory pacing strategy during the first half of MUM and sleep deprivation in the second half.