Isolation and characterization of mutants of Bacillus thuringiensis var. israelensis

Several mutants of Bacillus thuringiensis var. israelensis HD-500 (Bti) were obtained after treatment with N -methyl-n'-nitro- N -nitrosoguanidine. On the basis of the production (+) or absence (-) of spore (Spo) and crystal (Cry) the strains were grouped into three categories: Spo + Cry +, Spo + Cry - and Spo - Cry + . NGI-22, a Spo + Cry - mutant lacked all crystal proteins. Both NGI-23 and NGI-23-1 were Spo - Cry + . NGI-23-1, however, produced multiple crystals per cell. These mutants could prove useful not only for analysing sporulation and crystal formation as well as the linkage between the two genetic processes but also for improving the potential of Bti as a microbial insecticide.     

Tit for Tat: sticklebacks (Gasterosteus aculeatus) 'trusting' a cooperating partner

Individual three-spined sticklebacks (Gasterosteus aculeatus)moved closer to a predatory trout when a ‘cooperator’stickleback, which the test fish could see through a one-waymirror, swam up to the predator than when a ‘defector’stickleback appeared to swim only half as close to the predator.After four training runs with both types of partners, the formercooperator also defected. The test fish continued to move closerto the predator in the presence of the former cooperator eventhough both the former cooperator and the defector now appearedto stop in their approach to the predator at the same distance.This shows that probable partners build up trust.     

Monte Carlo simulation program for ecosystems

A Monte Carlo computer simulation program is designed in orderto describe the spatial and time evolution of a population ofliving individuals under preassigned environmental conditionsof energy. The simulation is inspired by previous techniquesdeveloped in physics — in particular, in molecular dynamicsand simulations of liquids — and it already provides somenew insights regarding macroscopic deterministic models in ecologyand concerning eventual control of artificial biomass productionplants. Received on July 15, 1986; accepted on October 9, 1986     

Dopamine-Dependent Postnatal Development of Enkephalin and Tachykinin Neurons of Rat Basal Ganglia

The influence of deprivation of the neurotransmitter dopamine (DA) on the development of [Met5]-enkephalin (ME) and substance P (SP) neuropeptide systems of the striatum was investigated in Sprague-Dawley rats. The neurotoxin 6-hydroxydopamine (6-OHDA) was used to induce DA deficiency on postnatal day 3 in rats, and the animals were killed at different postnatal time points until 35 days of age. The levels of ME and SP were determined by radioimmunoassay, and the abundance of preproenkephalin (PPE) and preprotachykinin (PPT) mRNA in the striatum was assessed by Northern blot hybridization analysis. The concentrations of DA, 5-hydroxytryptamine (5-HT), and their acid metabolites were determined by HPLC with electrochemical detection. The postnatal development of the PPE-derived peptide ME and the PPT-derived peptide SP closely paralleled the appearance of the respective mRNAs coding for these peptides. The dopaminergic lesion with 6-OHDA led to a marked depletion of DA and its metabolites but produced an increase in content of 5-HT and its metabolite in the striatum. The lesion did not affect the ME and PPE mRNA levels in the striatum up to 25 days but increased the levels at 35 days. In contrast, a decreased developmental expression in SP and PPT mRNA was observed throughout the observation period. The lesion failed to influence the development of the mRNA coding for the structural protein beta-actin. The results indicate that the normal development of enkephalin, tachykinin, and 5-HT systems of the striatum is dependent on the availability of DA, the integrity of dopaminergic neurons, or both. The studies provide evidence for an interrelationship and interdependence between the development of neurotransmitter and neuropeptide systems. It is suggested that an early developmental abnormality in the DA system could permanently alter the neuropeptide systems, which in turn could influence the progression and expression of the DA-deficiency state parkinsonism, Lesch-Nyhan disease, or both.     

Identification of a collagenase produced by Bacillus cereus R75E isolated from human colostrum

Applied Biochemistry and Microbiology - Recent studies have shown that the human colostrum and milk are a continuous supply of commensal, mutualistic and/or potentially probiotic bacteria to the...