Synthesis of β-glucanase and other extracellular proteins by cells and protoplasts of the yeast Pichia polymorpha

The synthesis of β-glucanase either by cells or by protoplasts of the yeast Pichia polymorpha has been found to occur in the presence of 2-deoxy-d-glucose in the growth medium. On the other hand, the synthesis of typical extracellular proteins such as invertase and acid phosphatase is strongly affected by the presence of the drug. The degree of inhibition is, however, directly related to the 2-deoxy-d-glucose concentration.     

Preliminary note on anti-insulin antibody formation in diabetics treated with porcine insulin

In the present study, we have tested the sera of sixty five diabetic patients treated with insulin, researching the action of some physiologic and therapeutic factors (sex, age, insulin dose and time of treatment), to production of anti-insulin antibodies. Our results have shown that an important percentage of diabetic patients treated by porcine insulin produce antibodies: 72% of studied patients, concerning chiefly all the women and patients under-fourty years old. However our results have not pointed out any relation between the administered insulin dose versus the anti-insulin antibodies production, in spite of the early production of these antibodies in a great part of the patients.     

Parasitic effect of Opius concolor (Spzl) (Hymenoptera, Braconidae) on an intermediate host Ceratitis capitata Wied (Diptera, Trypetidae)

The parasitic incidence of Opius concolor (Hymenoptera, Braconidae) on a replacement host, Ceratitis capitata (Diptera, Trypetidae) was studied using polyacrylamide gel electrophoresis and immunoelectrophoresis methods. A noticeable modification of C. capitata proteins was observed when parasited by O. concolor. But the most important phenomenon is the finding of common antigens between the host and the parasite. These results are discussed with regard to trophic and parasitic behaviour of the parasite.     

A 3-hydroxy-3-methylglutaryl-CoA synthase-based probe for the discovery of the acyltransferase-less type I polyketide synthases

Acyltransferase (AT)-less type I polyketide synthases (PKSs) produce complex natural products due to the presence of many unique tailoring enzymes. The 3-hydroxy-3-methylglutaryl coenzyme A synthases (HCSs) are responsible for β-alkylation of the growing polyketide intermediates in AT-less type I PKSs. In this study, we discovered a large group of HCSs, closely associated with the characterized and orphan AT-less type I PKSs through in silico genome mining, sequence and genome neighbourhood network analyses. Using HCS-based probes, the survey of 1207 in-house strains and 18 soil samples from different geographic locations revealed the vast diversity of HCS-containing AT-less type I PKSs. The presence of HCSs in many AT-less type I PKSs suggests their co-evolutionary relationship. This study provides a new probe to study the abundance and diversity of AT-less type I PKSs in the environment and microbial strain collections. Our study should inspire future efforts to discover new polyketide natural products from AT-less type I PKSs.     

Synthese d'Oligodesoxyribonucleotides sur Support de Gel de Silice par la Methode au Phosphotriester

Abstract

A method of oligonucleotide synthesis was developped on a silica gel support by the phosphotriester approach. Using this method, the nonanucleoside octaphosphate dT(pT)₈ was synthetized in 28% yield.