EFFECTS OF VASOACTIVE INTESTINAL PEPTIDE ON ACTIVITIES OF SUCCINIC DEHYDROGENASE AND ALKALINE PHOSPHATASE IN RAT HEPATOMA CELLS

Using cytochemical method,microspectrophotometry and image analysis,effects of va-soactive intestinal peptide(VIP)on activities of succinic dehydrogenase(SDH)and alkalinephosphatase(ALP)in rat hepatoma cells were studied in vitro.The results showed that thehepatoma cell expressed potent positive reactions of SDH and ALP,the positive positionswere located at the cell membranes and/or cytoplasm.Having been treated with VIP,ALPdecreased obviously in activity(P<0. 01,compared with hepatoma cells untreated by VIP).The sites of ALP activty were chiefly located at the cell membranes,particularly at the cell-cell contacts.Cultured rat hepatoma cells had intensive SDH activity in their cytoplasm.Compared with untreated eclls,there was no marked difference in the intensity of SDH activ-ity in VIP-treated hepatoma cells(P>0.05).     

赤子爱胜蚯蚓(Eisenia Foetida)纤溶酶的研究,Ⅳ纤溶酶组成成分的分子量测定

本文报告了用SephadexG—100柱层析法纯化样品和聚丙烯酰胺凝胶电泳测定纤溶酶组成成分的分子量的研究结果。经柱层析分离的纤溶酶电泳测定分子量结果为11条带,分别为68,000、49,000、42,000、41,000、36,000、29,000、27,000、26,000、25,000、21,000和12,000。而纤溶酶的主要组分集中在21.000与42.000之间,为其活性组分。     

Protein enrichment of sweet potato residue with co-culture of amylolytic fungi by solid-state fermentation

Protein enrichment of sweet potato residue with amylolytic moulds by solid-state fermentation was higher than that obtained with amylolytic yeasts. The optimum initial moisture content for protein enrichment was 66% to 75%. Incrementally added nitrogen sources to the culture at zero time and at 24 h considerably improved the final protein content. During the cultivation, the moisture, ash and ATP contents increased, while the pH value decreased. A 1:1 co-culture of amylolytic mycelial fungi yielded a product with 32.4% crude protein after 4 days incubation at 30 degrees C.     

Acid-Catalyzed nucleophilic substitution and racemization of 3-methoxy-N-desmethyldiazepam enantiomers in methanol

pK_a1 values of 3-methoxy-N-desmethyldiazepam in acetonitrile and methanol containing various acid concentrations were determined by spectrophotometry to be 3.5 and 1.3, respectively. Temperature-dependent racemization of enantiomeric 3-methoxy-N-desmethyldiazepam in methanol containing 0.5 M H₂SO₄ was studied by circular dichroism spectropolorimetry and the racemization reactions were found to follow apparent first-order kinetics. Thermodynamic parameters of the racemization reaction were found to be: E_act = 18.8 kcal/mol, and at 25°C: ΔH^? = 18.3 kcal/mol, ΔS^? = ?14.8 entropy unit, and ΔG^? = 22.7 kcal/mol, respectively. The racemization had an isotope effect (k_H/k_D) of 1.6 at 42°C. Based on the results of this report and those of earlier reports by other investigators, a nucleophilically solvated C3 carbocation intermediate resulting from either a P (plus) or an M (minus) conformation is proposed to be an intermediate and responsible for the stereoselective nucleophilic substitution and the subsequent racemization of 3-methoxy-N-desmethyldiazepam enantiomers. © 1993 Wiley-Liss, Inc.     

蛋白质结构成对比较的新方法

介绍一种蛋白质三维结构的快速比较方法.此方法毋需初始联配,而能自动寻找和智能迭代.利用本程序对珠蛋白、丝氨酸蛋白酶、天冬氨酸蛋白酶、钙结合蛋白和溶菌酶作了系统的结构比较,取得了满意的结果.本文也讨论了衡量联配结果好坏的要素问题.     

Redescription of the Chengjiang arthropod Squamacula clypeata Hou and Bergström, from the Lower Cambrian, south-west China

The anatomy of the arthropod Squamacula clypeata Hou and Bergström, 1997 from the Lower Cambrian Chengjiang Lagersta¨tte is redescribed based on four newly excavated specimens. The new material was collected from localities recently discovered in the Kunming area, Yunnan Province, south-west China, and preserves remarkable details of the ventral morphology, revealed by preparation. Squamacula clypeata is dorsoventrally flattened and rounded in outline. The cephalon was covered by a wide, short shield, with a large doublure and a pair of uniramous antennae on the ventral side. The thorax consists of nine somites, each protected by a tergite and carrying at least one pair of biramous limbs. The pygidium is covered with a small rounded tergum. The endopod is segmented, equipped with short spines on the inner margin of the coxa and a claw-like structure distally, and the exopod flap-like, fringed with setae. The limbs in the pygidium are like those in the thorax in shape. Squamacula was most probably a nektobenthic predator. The spinose endopod could walk, grasp and grind. The large flap-like exopod was adapted for swimming and respiration. Its affinities lie with the Arachnomorpha, but the relationships with other known taxa remain ambiguous.     

Enhancement of CO2 tolerance of Chlorella vulgaris by gradual increase of CO2 concentration

Summary Chlorella vulgaris UTEX259 was cultivated using two different methods of gas supply. In one method the CO₂ concentration in bubbled gas was held constant and in the other method it was increased gradually. Algal growth was almost linear after a short period of lag phase in both methods. With the constant CO₂ concentration, the CO₂ fixation rate in the linear growth phase decreased over 10%(v/v) CO₂, while the rate increased up to 6% CO₂. However, the rate was enhanced by using the latter incremental increase method, especially under a higher concentration of CO₂. The maximum rate of CO₂ fixation was 52 mg CO₂/l·h at 20% CO₂ during the gradual increase of CO₂ concentration.     

矩阵的加号逆理论在参数估计中的应用

本文从矩阵的加号逆理论出发,根据求矛盾线性方程组最佳逼近解的方法,建立起一种新的参数估计方法,同时给出了显著性检验方法,这种方法更简单更精确．     

一种具有纤溶活性的枯草杆菌蛋白激酶的研究──Ⅰ高产酶菌株的筛选与鉴定

本文主要阐述了一种具有纤溶活性的枯草杆菌（Ｂａｃｉｌｌｕｓｓｕｂｔｉｌｉｓ）蛋白激酶产生菌株的筛选与鉴定的研究结果。作者从初筛的１２株Ｂａｃｉｌｌｕｓｓｕｂｌｉｌｉｓ菌中,通过对固体发酵和液体发酵所产生的枯草杆菌蛋白激酶,用琼脂糖－纤维蛋白平板法测其活性,经比较不同菌株的活性,筛选出两株高产酶菌株：Ｂ．ｓｕｂｔｉｌｉｓＨＷ—１２和Ｂ．ｓｕｂｔｉｌｉｓＨＷ—３。同时对菌体和菌落形态特点、生理生化反应进行了鉴定,认为Ｂ．ＳｕｂｔｉｌｉｓＨＷ－１２菌株可用来做为发酵生产该酶的菌种。