Tunicamycin-resistant mutants of Bacillus amyloliquefaciens are deficient in amylase, protease and penicillinase synthesis and have altered sensitivity to antibiotics and autolysis

Mutants of Bacillus amyloliquefaciens resistant to at least 10 micrograms/ml of tunicamycin were isolated and shown to be pleiotropic. The mutants were more resistant to streptomycin, chloramphenicol, kanamycin and neomycin than was the parent strain but less resistant to penicillin G and tetracycline. They were more autolytic, presumably due to an altered cell wall. The mutants produced reduced levels of amylase, penicillinase and both metal and serine protease besides having an enhanced sporulation frequency and being more motile.     

Cytogenetical effects of ageing in seeds

Freshly harvested seeds of soybean and barley were artificially aged. The progeny showed a marked decrease in mitotic index and chromosomal aberrations of various types increased at both mitosis and meiosis, resulting in a significant loss of pollen viability as the ageing advanced. Studies on the types and frequencies of chlorophyll deficients and phenodeviants also showed an overall increase, suggesting that ageing mimics irradiation effects and produces alterations in the gene complexes resulting in the segregation of different kinds of phenotypic mutations.     

Filariasis and malaria sera from Orissa (India) lack human immunodeficiency virus (HIV) antibody reactivity

Reports exist indicating a correlation between seropositivity for human T-lymphotrophic virus (HTLV) antibodies and certain parasitic infections in some parts of the world. In 274 filariasis and 119 malarla sera examined from Orissa, none was reactive in a test for antibodies to human immunodeficiency virus (HIV).The author is with the AIDS Surveillance Unit, Regional Medical Research Centre (Indian Council of Medical Research), Bhubaneswar 751 016, India.     

Identification of a potentially neurotoxic pyridinium metabolite of haloperidol in rats

In vivo metabolic studies have revealed that haloperidol is converted to the corresponding pyridinium metabolite which has been characterized in both urine and brain tissues isolated from haloperidol treated rats. Unlike the corresponding conversion of the structurally related Parkinsonian inducing agent MPTP to the ultimate neurotoxic pyridinium metabolite MPP+, the oxidative biotransformation of haloperidol is not catalyzed by MAO-B. Microdialysis studies in the rat indicate that intrastriatal administration of this pyridinium metabolite is about 10% as effective as MPP+ in causing the irreversible depletion of striatal nerve terminal dopamine. The results point to the possibility that some of the neurological disorders observed in experimental animals and man during the course of chronic haloperidol treatment may be mediated by this pyridinium metabolite.     

Preliminary crystallographic data for the thiamin diphosphate-dependent enzyme pyruvate decarboxylase from brewers' yeast

Single crystals of the thiamin diphosphate (the vitamin B1 coenzyme)-dependent enzyme pyruvate decarboxylase (EC 4.1.1.1) from brewers' yeast have been grown using polyethylene glycol as a precipitating agent. Crystals of the homotetrameric version alpha 4 of the holoenzyme are triclinic, space group P1, with cell constants a = 81.0, b = 82.4, c = 116.6 A, alpha = 69.5 beta = 72.6, gamma = 62.4 degrees. The crystals are reasonably stable in a rotating anode x-ray beam and diffract to at least 2.5 A resolution. The Vm value of 2.55 A/dalton is consistent with a unit cell containing four subunits with mass of approximately 60 kDa each. Rotation function results with native data indicate strong non-crystallographic 222 symmetry relating the four identical subunits, thus density averaging methods are likely to play a role in the structure determination.     

Lactic acid extraction with trioctyl amine

Lactic acid extraction was carried out with trioctyl amine (TOA) in three diluents. The effect of initial lactic acid concentrations on the extraction efficiency was investigated. It was observed that although the percentage extraction remained constant or decreased but the loading ratio was increased in all the cases. The overloading was observed in the case of TOA in methyl isobutyl ketone (MIBK). The extraction of lactic acid was favored at a lower aqueous pH?in all the diluents. The improvement of the extraction efficiency at a higher aqueous pH?(=?6) was achieved by using the modified TOA (treated with HCl) in MIBK. However, the recovery of lactic was very poor in the case of modified TOA in MIBK, although the complete recovery was obtained for untreated TOA.     

Primary cell culture from fish gills and kidney using fish serum

A novel, cost effective and time saving technique for primary cell culture from gills and kidney using fish serum has been developed. Single cell suspension of gills and kidney of Clarias gariepinus was obtained by trypsinization. Minimum essential medium supplemented with 10% fish serum in place of 10% foetal calf serum and 20% fish muscle extract, yielded confluent monolayer on 6th and 8th day in gill and kidney tissue respectively at 28 degrees C. Fish serum can be successfully used as media supplement for cultivation and maintenance of primary cell culture from fishes.