Glial fibrillary acidic protein in regenerating teleost spinal cord

Immunohistological and ultrastructural studies were carried out on normal and regenerating spinal cord of the gymnotid Sternarchus albifrons, and in the brain and spinal cord of the goldfish Carassius auratus, to examine the distribution of glial fibrillary acidic protein (GFAP) in these tissues. Sections of normal goldfish brain and spinal cord exhibited positive staining for GFAP. In normal Sternarchus spinal cord, electron microscopy has revealed filament-filled astrocytic processes; however, such astrocytic profiles were more numerous in regenerated cord. Likewise, while normal Sternarchus spinal cord showed only a small amount of GFAP staining, regenerated cords were strongly positive for GFAP. Positive staining with anti-GFAP was observed along the entire length of the regenerated cord in Sternarchus, and was especially strong in the transition zone between regenerated and unregenerated cord. Both regeneration of neurites and production of new neuronal cell bodies occur readily in such regenerating Sternarchus spinal cords (Anderson MJ, Waxman SG: J Hirnforsch 24: 371, 1983). These results demonstrate that the presence of GFAP and reactive astrocytes in Sternarchus spinal cord does not prevent neuronal regeneration in this species.     

子宫颈糜烂病毒病因的探讨

491份宫颈拭子病毒分离结果表明:糜烂宫颈单纯疱疹病毒(HSV)分离阳性率(30.8％)是正常宫颈(2.6％)的11.8倍,用人干扰素治疗一个疗程后,病毒分离率下降至疗前的1/4.36例糜烂宫颈活体组织DNA分子杂交表明,乳头瘤病毒16型(HPV-16)阳性者占52.8和,HPV-18占17.9％,HPV-6B占28.1％,HPV-11占7.7％,251例宫颈糜烂患者经人(?)D型基因工程干扰素双盲对比治疗后,总有效率达93.8％,显效率达60％,分析临床疗效与HSV分离率的变化表明,临床有效病例中有35％(49/140)在治疗后病毒阴转,有57％在疗前疗后均未分离出HSV,有5％在疗前疗后保持阳性不变,有2.9％疗前阴性,疗后阳性,上述结果表明,HSV和HPV与慢性宫颈炎有一定关系。     

赤霉素产生菌~#85104菌株原生质体的形成再生和紫外光对原生质体诱变条件的研究

赤霉产生菌在正常条件下不产生孢子,育种材料以多核菌丝体及其碎片为主,大部分常用的诱变剂对它们诱变效应较差。本文报导有关赤霉素产生菌~#85104菌株原生质体的获得、再生和紫外光诱变原生质体的条件,甘氨酸对菌丝体生长的影响,以及采用二硫苏糖醇预处理菌丝体等方面条件的研究。在采用紫外光照射原生质体的诱变处理下,已获得数株高产的新菌株。     

荔枝果皮多酚氧化酶酶促褐变的研究

从荔枝果皮分别提取多酚氧化酶及其天然底物,两者相作用,形成褐色产物,酶促褐变是荔枝果皮变褐的原因。 从荔枝果皮提取的酚类物质中分离出多酚氧化酶的天然底物。此底物的紫外吸收光谱分别在215和280 nm有一强的和一弱的吸收峰,它的红外吸收光谱在3190、1600、1500 cm~(-1)有很强的吸收峰。     

The effect of transferrin saturation on internal iron exchange

Radioiron was introduced into the intestinal lumen to evaluate absorption, injected as nonviable red cells to evaluate reticuloendothelial (RE) processing of iron, and injected as hemoglobin to evaluate hepatocyte iron processing. Redistribution of iron through the plasma was evaluated in control animals and animals whose transferrin was saturated by iron infusion. Radioiron introduced into the lumen of the gut as ferrous sulfate and as transferrin-bound iron was absorbed about half as well in iron-infused animals, and absorbed iron was localized in the liver. The similar absorption of transferrin-bound iron suggested that absorption of ferrous iron occurred via the mucosal cell and did not enter by diffusion. The decrease in absorption was associated with an increase in mucosal iron and ferritin content produced by the iron infusion. An inverse relationship (r = -0.895) was shown between mucosal ferritin iron and absorption. When iron was injected as nonviable red cells, it was deposited predominantly in reticuloendothelial cells of the spleen. Return of this radioiron to the plasma was only 6% of that in control animals. While there was some movement of iron from spleen to liver, this could be accounted for by intravascular hemolysis. Injected hemoglobin tagged with radioiron was for the most part taken up and held by the liver. Some 13% initially localized in the marrow in iron-infused animals was shown to be storage iron unavailable for hemoglobin synthesis. These studies demonstrate the hepatic trapping of absorbed iron and the inability of either RE cell or hepatocyte to release iron in the transferrin-saturated animal.     

Differential insulin responses to oral and intravenous glucose in the transplantable rat insulinoma--a role for GIP

We have previously demonstrated an impaired insulin response to intraperitoneal glucose and arginine by the transplantable NEDH rat insulinoma. The nature of this tumour B-cell defect has been further studied by investigating the response of insulinoma-bearing rats to intravenous and intragastric glucose. Intravenous glucose failed to stimulate plasma immunoreactive insulin (IRI) above high basal levels (14.5 +/- 1.1 micrograms/L). However, significant elevation of the plasma IRI concentration was observed following an intragastric glucose load (17.1 +/- 1.5 micrograms/L; P less than 0.02). In view of the different effects of oral and intravenous glucose on insulin secretion in the RIN, implicating an involvement of incretin factors from the gut, the response of the tumour to GIP was investigated. Plasma IRI concentrations rose significantly in these animals (20.6 +/- 2.5 micrograms/L at 5 min, P less than 0.02). We conclude that (a) the transplantable rat insulinoma is responsive to GIP, and (b) that whilst the tumour B-cell has lost its insulin responsiveness to hyperglycaemia produced by intraperitoneal or intravenous glucose, it retains its ability to respond to intragastric glucose. This could be due to incretin factors from the gut of which GIP is currently the strongest candidate.     

Comparison of mammalian VIP bioactivities in dispersed acini from guinea pig pancreas

Mammalian VIP is identical in pig, cow, human, rat, dog and goat but differs in the guinea pig (GP) in positions 5, 9, 19, and 26. We now demonstrate that GP, goat, rat and synthetic mammalian VIP are indistinguishable in their inhibition of binding of 125I-labelled synthetic VIP to dispersed acini from GP pancreas and that GP, pig, dog, goat and synthetic VIP are also similar in their efficacy and potency in stimulating amylase release from these acini. Thus in spite of the differences in amino acid sequence, GP VIP appears to have full biologic potency in its action on dispersed acini from GP pancreas.     

Column cellulose hydrolysis reactor: Cellulase adsorption profile

Summary A column cellulose hydrolysis reactor was set up using a single passage of cellulase enzyme which was followed with a continuous percolation of buffer. Hydrolysis rates were found to decline precipitously upon the removal of the non-adsorbed cellulase components. By comparing specific activities of the cellulase before and after adsorption on the cellulose column, it was concluded that the adsorption efficiencies for the cellulase components decreased from exoglucanase (1,4--d-glucan cellobiohydrolase EC 3.2.1.91) to endoglucanase [1,4-(1,3;1,4)--d-glucan 4-glucanohydrolase, EC 3.2.1.4] to -glucosidase (-d-glucoside glucohydrolase, EC 3.2.1.21). Of the adsorbed cellulase components, the rate of endoglucanase leaching from the cellulose column was 20 times that for the exoglucanase despite the greater adsorption efficiency of the latter. By analysing the cellulase components which were bound and not bound by the cellulose column and comparing them with a purified exoglucanase enzyme on sodium dodecyl sulfate polyacrylamide gels, it was confirmed that the major cellulase component adsorbed to the cellulose column was an exoglucanase component. The resultant loss of other cellulase components from the reactor was probably the cause for the much reduced rate of cellulose hydrolysis when these components were flushed out of the column.     

Column cellulose hydrolysis reactor: An efficient cellulose hydrolysis reactor with continuous cellulase recycling

Summary The use of a column cellulose hydrolysis reactor with continuous enzyme recycling was demonstrated by incorporating a continuous ultrafiltration apparatus at the effluent end of the column reactor. Using this setup, over 90% (w/v) cellulose hydrolysis was achieved, resulting in an average sugar concentration of 6.8% (w/v) in the effluent stream. The output of the system was 1.98 g of reducing sugar/l/h with a ratio of 87% (w/v) of the reducing sugars being monomeric sugars. Batch hydrolysis reactors were less effective, resulting in 57% (w/v) of the cellulose being hydrolyzed. The output of the batch reactor was 1.33 g of reducing sugar/l/h with similar product concentrations and percentage of monomeric sugars. The ratio of reducing sugar/filter paper unit of cellulase activity for the column method was 69.1 mg/U as compared to only 21.2 mg/U for the batch reactor.     

The significance of the aprotic solvent in monomer studies related to the primary subunit environment in the macromolecule

An advantage of aprotic polar solvent systems in the study of monomer interactions relevant to the macromolecular state is demonstrated with the measurement of nucleoside amino proton exchange rates in DMSO/water mixtures. The DMSO/water solvent provides the first unequivocal observation of general acid catalysis of nucleic acid amino proton exchange, which is undetectable in aqueous solution due to the formation of the endocyclic protonated nucleobase. Suppression of nucleobase protonation in the presence of buffer acid is a consequence of anion desolvation in the aprotic solvent. The detected route of general acid catalysis is demonstrated as a consequence of Watson-Crick H-bonding, leading to the implication that amino chemistry is modulated in the helical state to decrease amino proton lifetime in the closed macromolecular context of conformational information obtained by hydrogen exchange methods. This useful property of the aprotic solvent can be extended to monomeric studies pertaining to specific local site interactions affecting the function and conformation of proteins and nucleic acids.