乳腺癌中着丝粒蛋白CenpG的差异表达

用间接免疫荧光（IIF）验证了着丝粒蛋白CenpG的一种抗血清；通过对31例乳腺癌组织块及每一例病人的癌旁正常（非癌性）组织块蛋白提取物进行免疫印迹（Western blot）分析，发现多数情况下（71%）癌组织中着丝粒蛋白CenpG(95kD)过表达；在两例乳腺癌组织中还发现了一种能被CenpG抗血清识别的43kD蛋白质成分。结果表明，新近发现和命名的CenpG（或者还有其他相关成分）的差异表达可能与细胞恶性增殖有关。     

The effects of induction conditions on production of a soluble antitumor sFv in Escherichia coli

CC49 is a second generation monoclonal antibody(mAb) with highaffinity to a pancarcinoma antigen, TAG-72. A single-chain Fv(sFv)ofCC49 may have a role in managing human carcinomas. Most reportedsFvs have been expressed as insoluble products that must besolubilized and renatured. Soluble sFv expression is advantageousas activity can be assayed directly from the periplasmic fraction.Also, gene-level immunoconjugates may not be amenable to refoldingprotocols. Using a vector that carries the tac promoter andomp A signal, we have examined the effects of four variableson the expression and accumulation of soluble CC49 sFv: (i)linker sequence joining VL and VH, (ii) isopropylthio-ß-D-galactosideconcentration for induction, (iii) temprature, and (iv) theaddition of nonmetabolizable sugars to the medium. We have beenable to demonstrate, using rapidly prepared periplasmic extracts,that the yield of soluble sFv improves by the addition of 0.4Msucrose to the medium and by inducing expression with a verylow concentration of IPTG (0.02–0.03 mM). Under theseinduction conditions periplasmic extracts demonstrate increasedexpression of the sFv, as shown by the larger amount of a 27kDa band on SDS-polyacrylamide gel, and an increased abilityto inhibit binding of the mAb CC49 to immobilized tumor extracts.     

Automating the identification and analysis of protein {beta}-barrels

ßBarrels are widespread and well-studied featuresof a great many protein structures. In this paper an unsuper-visedmethod for the detection of P-barrels is developed based ontechniques from graph theory. The hydrogen bonded connectivityof ß-sheets is derived using standard pattern recognitiontechniques and expressed as a graph. Barrels correspond to topologicalrings in these connectivity graphs and can thus be identifiedusing ring perception algorithms. Following from this, the characteristictopological structure of a barrel can be expressed using a novelform of reduced nomenclature that counts sequence separationsbetween successive members of the ring set These techniquesare tested by applying them to the detection of barrels in anon-redundant subset of the Brookhaven database. Results indicatethat topological rings do seem to correspond uniquely to ß-barrelsand that the technique, as implemented, finds the majority ofbarrels present in the dataset.     

吲哚美辛对荷瘤小鼠抗肿瘤作用机制的实验研究

用微观放射自显影技术及免疫组化法探讨了非甾体类抗炎药吲哚美辛(IN)对Lewis肺癌的生长抑制作用机制。结果显示:与对照组相比,实验组IN的抑瘤率为55.05%;IN可显著下调Bcl-2蛋白的表达(t=6.154,P<0.001),对Bax蛋白的表达没有明显影响(t=2.101,P>0.05)。放射自显影结果显示,在肿瘤细胞的细胞膜、细胞浆及细胞核中均有黑色银颗粒分布,且在用药后12 h时肿瘤组织中的平均银颗粒数高于4、7、243、6 h时。以上结果表明,IN可抑制Lewis肺癌的生长,其机制与下调抗凋亡蛋白Bcl-2的表达及降低Bcl-2/Bax的比值有关;IN可进入到肿瘤细胞内发挥抗肿瘤作用。     

Nutritional response of mature rats to kidney bean (Phaseolus vulgaris) lectins

In a series of 10-day pair feeding experiments it was found that the nutritional value of diets containing beans was essentially the same for rats aged between 30 and 123 days. Thus net protein utilisation (NPU) values of 25–39 on diets containing Processor bean (35 g protein kg^?1) + egg albumin (65g protein kg^?1) were obtained. As food intakes were considerably reduced when rats were fed diets containing more than 35g protein kg^?1 of Processor bean, the measurement of protein utilisation became increasingly more difficult. The severe disruption of the brush borders of duodenal and jejunal enterocytes, originally observed when bean-containing diets were fed to young (30-day-old) rats was also found with rats up to the age of 120 days on similar diets. Similarly, the development of circulating anti-lectin antibodies in the animals showed no age dependence within the age limits investigated. It was also shown that oral immunisation did not protect the rats from the effects of toxicity and that the immune response was a result of continuous absorption of lectin throughout the feeding period. Thus the extent and the mechanism of toxicity of Phaseolus vulgaris bean lectins were found not to be dependent on the age or maturity of the animal.     

Drying of Probiotics: Optimization of Formulation and Process to Enhance Storage Survival

This work describes how probiotic bacteria can be dried at low temperature in two steps, combining spray drying and vacuum drying, in order to enhance their survival during storage. A sufficient number of dried probiotics survived storage for more than 3 months at 30°C, if an appropriate combination of protein and carbohydrate was selected as carrier and storage conditions were maintained optimal. The use of soy protein and maltodextrin or skim milk and arabic gum resulted in the best survival rates of probiotics during storage. No evident difference was found between different spray dryer configurations, although a cocurrent flow was preferred.     

V. Yeast sequencing reports. Identification of a gene encoding a new Ypt/Rab-like monomeric G-protein in Saccharomyces cerevisiae

A Saccharomyces cerevisiae sequence cloned by serendipity was found to encode a protein that is a new member of the Ypt/Rab monomeric G-protein family. This sequence shows high homology to the yeast genes SEC4 and YPT1 and, like SEC4 and YPT1, is essential for viability. The sequence was localized to chromosome V based upon hybridization to pulse-field gel-separated yeast chromosomes. The sequence has been deposited in the GenBank data library under Accession Number L17070.     

Properties of Edible Films from Total Milk Protein

The mechanical properties and water vapor permeability of edible films made from various total milk proteins (TMPs) were investigated. Two TMPs obtained from nonfat dry milk (NDM) by removing lactose and three TMPs obtained from a commercial source were studied. Lactose was extracted from NDM by ultrafiltration or suspension in ethanol followed by filtration. TMP concentrate obtained by ultrafiltration (UF) produced films with the lowest water vapor permeability (WVP) and the highest tensile strength at break. Commercial TMP concentrates produced films more ductile than those from the UF-TMP or retentate from ethanol extraction. Further research is needed to improve mechanical properties of UF-TMP films without increasing the WVP.     

A new family of yeast genes implicated in ergosterol synthesis is related to the human oxysterol binding protein

We have identified three yeast genes, KES1, HES1 and OSH1, whose products show homology to the human oxysterol binding protein (OSBP). Mutations in these genes resulted in pleiotropic sterol-related phenotypes. These include tryptophan-transport defects and nystatin resistance, shown by double and triple mutants. In addition, mutant combinations showed small but apparently cumulative reductions in membrane ergosterol levels. The three yeast genes are also functionally related as overexpression of HES1 or KES1 alleviated the tryptophan-transport defect in kes1Δ or osh1Δ mutants, respectively. Our study implicates this new yeast gene family in ergosterol synthesis and provides comparative evidence of a role for human OSBP in cholesterol synthesis.