Lectin bindings and diethylstilbestrol effects on the recognition of mullerian inhibiting substance (MIS) on chick mullerian ducts by MIS-antiserum

Summary A high intensity of lectin bindings was demonstrated on the epithelial cells and serosa cells of the regressing right Mullerian ducts (Mds) in the female chick embryos. The strong lectin bindings occurs on, or in the regressing Md cells along with marked surface MIS bindings at the age of day 13. However, at the age of days 5–7 1/2, bindings of lectins were weak. Neither Wheat-germ agglutinin (WGA) or Concanavalin A (Con-A) labelings before MIS-antiserum (MIS-Ab) incubation can block antibody recognitions to the antigens, including MIS and growth hormone at the age of day 13. Our previous studies indicated that after WGA labeling on the surfaces of Md epithelial cells prior to the incubation of MIS-Ab at day 10 did not prevent the recognition of MIS-Ab (Wang 1989). On the contrary, at day 7 1/2, the specific binding of MIS was eliminated after preincubations with lectins and prenatal diethylstilbestrol (DES) treatment at the age of day 5. It is suggested that DES provides a protection to the Mds from MIS-induced regression by preventing the MIS binding to its specific membrane receptors. An increase of extra- and intracellular glycoproteins or carbohydrates of regressing Md epithelial cells were suggested. Internalization of WGA but not MIS molecules was found in Md epithelial cells. The Golgi saccules were negative of lectin bindings.     

Transformation of Tetrahymena thermophila with hypermethylated rRNA genes.

The extrachromosomal rRNA genes (rDNA) of Tetrahymena thermophila contain 0.4% N6-methyladenine. C3 strain rDNA was isolated, hypermethylated in vitro, and microinjected into B strain host cells. Clonal cell lines were established, and transformants were selected on the basis of resistance to paromomycin, conferred by the injected rDNA. The effects of methylation by three enzymes which methylate the sequence 5'-NAT-3', the dam, EcoRI, and ClaI methylases, were tested. Hypermethylation of the injected rDNA had no effect on transformation efficiency relative to mock-methylated controls. The injected C3 strain rDNA efficiently replaced host rDNA as the major constituent of the population of rDNA molecules. Hypermethylation of the injected DNA was not maintained through 20 to 25 cell generations.     

Differential effects of transforming growth factor-beta on the synthesis of extracellular matrix proteins by normal fetal rat calvarial bone cell populations

To determine the effects of transforming growth factor-beta (TGF-beta) on the different cell types that exist in bone, cell populations (I-IV), progressively enriched in osteoblastic cells relative to fibroblastic cells, were prepared from fetal rat calvaria using timed collagenase digestions. TGF-beta did not induce anchorage-independent growth of these cells, nor was anchorage-dependent growth stimulated in most populations studied, despite a two- to threefold increase in the synthesis of cellular proteins. In all populations the synthesis of secreted proteins increased 2-3.5-fold. In particular, collagen, fibronectin, and plasminogen activator inhibitor synthesis was stimulated. However, different degrees of stimulation of individual proteins were observed both within and between cell populations. A marked preferential stimulation of plasminogen activator inhibitor was observed in each population, together with a slight preferential stimulation of collagen; the effect on collagen expression being directed primarily at type I collagen. In contrast, the synthesis of SPARC (secreted protein acidic rich in cysteine/osteonectin was stimulated approximately two-fold by TGF-beta, but only in fibroblastic populations. Collectively, these results demonstrate that TGF-beta stimulates matrix production by bone cells and, through differential effects on individual matrix components, may also influence the nature of the matrix formed by different bone cell populations. In the presence of TGF-beta, osteoblastic cells lost their polygonal morphology and alkaline phosphatase activity was decreased, reflecting a suppression of osteoblastic features. The differential effects of TGF-beta on bone cell populations are likely to be important in bone remodeling and fracture repair.     

Transforming activities of sodium fluoride in cultured Syrian hamster embryo and BALB/3T3 cells

The transforming activity of sodium fluoride was studied in the SHE and the BALBl3T3 cell culture systems. Initiating and promoting activities were then investigated by means of the orthogonal methodology. Sodium fluoride was found to induce morphological transformation of SHE cells seeded on a feeder layer of X-irradiated cells at high concentrations (75–125 g/ ml). When the cells were seeded in the absence of a feeder-layer, the transformation frequencies increased in a dose-dependent manner with the concentrations of sodium fluoride ranging from 0 to the highly toxic concentration of 200 g/ml. In the BALBl3T3 cell system, sodium fluoride was negative in the standard Kakunaga procedure, while through the experiment designed by table L₈ (2⁷) of the orthogonal method, an initiating-like effect and a weak promoting activity were detected within the concentrations ranging from a 25 g/ ml to a 50 g/ ml concentration which is highly toxic for BALBl3T3 cells. From these results, it is suggested that, besides a genetic mode of action, sodium fluoride could possibly act through a non-genotoxic mechanism.Abbreviations CE cloning efficiency - NaF sodium fluoride - SHE Syrian hamster embryo - TF transformation frequency     

九江地区人头发横断面的研究

本文对九江市汉族463例健康人,4710根头发横断面进行观察和显微测量。分析了本地区人年龄与头发直径的关系、年龄与头发黑色素颗粒分布的关系。结果表明:黑色素颗粒随年龄增长而渐浓密,成年人最丰富,老年人头发黑色素颗粒则渐崩溃稀少;头发各径亦随年龄增长而增大,而老年人头发各径是逐渐减小。此外,本文还同欧、亚、美国各民族人头发资料进行比较。根据头发指数,确定本市人头发形伏为直发形。     

我国若干地区蜡样芽孢杆菌723株噬菌体分型的初步报告

四年来,作者由水中获取蜡样芽孢杆菌噬菌体13株,旨在试作噬菌体分型。待检菌株共723株,由国内16个地区提供(其中食物中毒株121株;食品株602株)。分型结果显示:C29、C30、C24、C27、C19和A_4等型别占优势。中毒株     

鹅掌楸种子和胚胎发育的研究

应用控制授粉、软 X-射线法、常规石蜡制片法和荧光检测等手段,研究了鹅掌楸(Lirio-dendron chinense(Hemsl.)Sarg.胚胎发育和控制授粉与结籽率的相关性。控制授粉后2小时花粉萌发,6小时萌发率最高,柱头可授期持续30小时左右。花粉管借助于柱头毛之间的分泌物进入柱头沟,经花柱沟、珠孔塞和珠心冠原进入胚囊,行珠孔受精。授粉后2周,胚乳为2至3细胞厚的狭组织;第6周,胚乳充满胚囊腔,珠心随之解体殆尽;第7到8周,球形胚、心形胚发生;第14到16周,子叶形成;第22周种子或熟,胚乳丰富。单株自然授粉结籽率不足1%。控制授粉后,单个聚合果的最高结籽率可达39%,9个聚合果的平均结籽率为17.7%。     

An endemic brackish water faunule from the middle jurassic of southern qinghai province,China

An endemic brackish water faunule consisting of three taxa of bivalves,Hudsonella sinensis (Chen) n. gen.,Hudsonella sp., andProtocardia hepingxiangensis Chen & Lin occurs in the Bajocian of the southern Qinghai province, China.Hudsonella sinensis is a very variable species with a hinge structure characteristic of the subfamily Pachydontinae of the family Corbulidae. According to both geochemical data (stable carbon isotopes and the strontium/barium ratio) and ecological data the faunule lived in a brackish water embayment of mesohaline salinity (5#x2013;18 per mil) burrowing in soft substrate.     

Characterization of a human cervical carcinoma-associated antigen by lectin binding and immuno-electron microscopy

Summary The specific binding and nature of the epitope recognized by monoclonal antibody (Mab) 1H10, which binds an antigen expressed on human cervical tumors, was characterized by enzyme digestion, lectin competition assay and immuno-electron microscopy. Membrane homogenates of CaSki cervical carcinoma cells were digested with various enzymes, then analysed by SDS-PAGE and immunoblotting. Cells grown on coverslips were treated with various enzymes and in situ binding of Mab 1H10 to cells was analysed by electron microscopy. The ability of lectin-conjugates to block Mab 1H10 binding to CaSki cells was also examined. Treatment of samples with sodium periodate abrogated antigen recognition by Mab 1H10. Neuraminidase and hyaluronidase digestion decreased but did not eliminate Mab 1H10 binding to cells in situ. Chondroitinase ABC digestion, in contrast, removed Mab 1H10 binding sites both in vitro and in situ. Trypsin and chymotrypsin digestion of cell membrane homogenates decreased the molecular weight of the Mab 1H10 antigen but did not decrease the binding intensity. Wheat germ agglutinin (WGA) strongly bound to CaSki cells and partially blocked Mab 1H10 binding, indicating that the antigen contains N-acetyl-galactosamine residues at or near the epitope recognized by Mab 1H10. Ricinus communis agglutinin (RCA) exhibited a similar binding pattern to WGA. However, concanavalin A bound only weakly to CaSki cells and was ineffective at blocking Mab 1H10 binding. The tumor-associated antigen recognized by Mab 1H10 is concluded to be a chondroitin sulphate glycoprotein or proteoglycan rather than a mucopolysaccharide or lipoprotein.