Effects of pisatin on Dictyostelium discoideum: its relationship to inducible resistance to nystatin and extension to other isoflavonoid phytoalexins

Dictyostelium discoideum amoebae can acquire resistance to otherwise inhibitory concentrations of pisatin, an isoflavonoid phytoalexin of pea, and nystatin, a polyene antibiotic, following pretreatment with sublethal concentrations of these compounds. Additionally, growth on medium containing pisatin can induce nystatin resistance. We show here that distinct mechanisms mediate the inducible resistance to these two compounds because it is possible to isolate mutations that specifically block the induction of nystatin resistance but do not affect the induction of pisatin resistance. Pisatin did not affect wild-type sterol biosynthesis; therefore, the induction of nystatin resistance by pisatin is probably not via an alteration of membrane sterols. The inducible pisatin resistance phenotype was shown to extend to the isoflavonoid phytoalexins maackiain and biochanin A, and all three compounds inhibited the aggregation of amoebae that is normally triggered by starvation. Received: 23 February 1998 / Accepted: 26 June 1998     

Effect of short-term heat treatment of rice seedlings on sensitivity of thylakoid membranes to photoinhibition

The after-effects of 24 h high temperature (35 or 45 °C) treatment on the photochemical activities and photooxidative lipid peroxidation, subsequent to their irradiation were studied in 7-d-old etiolated rice (Oryza sativa) seedlings. Photosystem (PS) 1 and PS 2 mediated photoreactions of thylakoids isolated from the seedlings exposed to high temperature did not differ significantly from the thylakoids isolated from control seedlings (25 °C). Hence, all kinds of tested thylakoids were equally efficient in capturing and utilizing radiant energy. The high irradiance induced loss in PS 2 activity and lipid peroxidation measured in terms of malondialdehyde production was more rapid in thylakoids isolated from stressed seedlings as compared to that of control seedlings. Thus the thylakoids isolated from the stressed seedlings were more prone to photodamage than those from the control seedlings.     

Physicochemical Characterization and In Vitro Digestibility Study of an In Silico Designed Recombinant Protein Enriched with Large Neutral Amino Acids and Lacking Phenylalanine for Phenylketonuria

The Protein Journal - In our previous study, a 3D structure of LNAA66 model protein containing 4–5 α-helices, high large neutral amino acids (LNAA) and lacking phenylalanine was...     

Icthyofaunal Diversity of Siang River in Arunachal Pradesh,India

Study was carried out from June 2012 to July 2013 in a 58 km stretch of the river Siang in Arunachal Pradesh, India to determine ichthyofaunal diversity in this section of the river. The study revealed the presence of 82 species of fishes belonging to 8 orders, 24 families and 53 genera. Species representing the order Cypriniformes dominated the ichthyofauna while those representing Tetradontiformes are in less number.     

Occurrence of histone-related oxalate binding in rat liver nucleus

The rat liver nuclear oxalate binding protein was isolated, purified by anion and cation exchange column chromatography using Diethyl Amino Ethyl Sephadex, Carboxy Methyl Cellulose and Carboxy Methyl Sephadex C-50 ion exchangers. The purified oxalate binding protein was found to be H1B of H1 fraction of histories. Kinetic analysis of oxalate binding showed the presence of two affinity sites, one with Kd of 133.5 nM and Bmax of 40 pmoles and another with Kd of 262.5 nM and Bmax of 210 pmoles. The optimal oxalate binding was at pH 4.2 and at 28°C. The oxalate binding was specific and reversible and not due to ionic charge interaction. The IC₅₀ of other dicarboxylates was higher than that of oxalate. EGTA had no effect on oxalate binding but di- and tri-carboxylate carrier inhibitors and thiol modifying agents significantly lowered the binding activity. Oxalate binding to histones was significantly reduced in the presence of DNA or nucleotides, but RNA had no effect. ATP completely inhibited the oxalate binding activity at 1 mM concentration. Different tissues exhibited oxalate binding showing ubiquitous nature. Calf thymus H1 showed maximal binding similar to liver histones.Abbreviations ADP Adenosine diphosphate - ATP Adenosine triphosphate - DNA Deoxyribonucleic acid - RNA Ribonucleic acid