Isolation of nisin from native solution and its purification on cationites]

It was found possible to use organic sorbents and in particular carboxylic cationites for isolation of nisin from the fermentation broth filtrate and its purification. Nisin is known as a polypeptide antibiotic applied as a preservative. The sorbents were shown to have high exchange capacities by the isolated substance and mechanical strength and resistance. They also proved to be highly stable.     

Antibiotic activity of marine gram-negative bacteria]

An antimicrobial substance was isolated from the culture fluid of Vibrio fischeri belonging to ++gram-negative sea bacteria. The substance was shown to be highly active against ++gram-positive cocci and less active against some other ++gram-positive bacteria and fungi. The active substance was defined as a low molecular weight compound which appeared to be thermostable and had positive ninhydrin reaction. The antibiotic formed when the culture was grown in the media containing sea water and protein hydrolysates or yeast extract during the exponential phase. The maximum antibiotic activity was observed during the stationary phase of culture development.     

cGMP-binding centers in photoreceptor membranes

The binding of cGMP by structural components of bovine rod outer segments was studied. The discs and plasma membranes were shown to contain two types of the specific binding sites for cGMP which are distinct from cyclic GMP phosphodiesterase. The sites have a "high" and "low" (Kd = 0.1 divided by 0.35 and 1.5 divided by 2.0 X 10(-6) M respectively) affinity for cGMP. They belong to membraneous integral proteins presumably associated with phospholipids. Their affinity for cGMP is controlled by GTP and calmodulin.     

Nisin adsorption on silica adsorbents

It has been shown that silica adsorbents can be used for adsorption of nizin from solutions obtained after centrifugation of the fermentation broth. The optimal structure of the adsorbent pores has been determined. Silica with pores 50 to 75 nm in size provided the highest adsorption rates. The value of silica adsorption of nizin depended on the medium pH. The maximum adsorption rates were observed at pH 6.5--7. At pH 3.5 the level of nizin adsorption was low.     

Use of adsorbents for optimizing the process of isolating nisin from the culture broth

The results of the study on optimization of the process of nisin isolation from the cultural liquid are presented. Different adsorbents, streptococcal cells, medium solid particles (biomass fermentalysates) and silica gel, were used for antibiotic adsorption.     

中国皿蛛科——新纪录属及天山前延首蛛的重描述（蜘蛛目：皿蛛科）

本文记述我国皿蛛科一新纪录属:前延首蛛届Archaraeoncus Tanasevitch 1987,并对天山前延首蛛A.tianshanicus(Hu et Wu,1989)n.comb.重新作了描述,本种的雌蛛系首次发现。本文还对Araeoncus tianschanica Hu et Wu 1989原学名命名的原始拚缀作了改正。文中测量数据均以mm为单位。     

The effect of camphor on bacterial bioluminescence

Summary The inhibitory effect of camphor on bioluminescence of both bacteria and bacterial luciferase has been examined. The camphor has been shown to be a substrate of cytochrome P-450 of the luminous bacteria Photobacterium fischeri. The inhibition of the luminescence reaction provided evidence for the competitive nature of the interaction of camphor and aliphatic aldehyde at the binding site for luciferase. Camphor is also supposed to interact with P-450. The findings indicate that the hydroxylation process of camphor affects the kinetics of the luminescence.     

Effect of the initial pH value of the medium on the growth of Streptococcus lactis and the biosynthesis of nisin]

The effect of the initial pH value of the medium within 4.0 to 6.6 on the growth of Str. lactis and biosynthesis of nicin was studied. It was found that at the initial pH 4.0--4.5 of the medium the growth of the culture was poor, i.e. 11--14% of the control (initiral pH 6.6). With an increase in the value of the initial pH at least to 5.0 the growth of Str. lactis also increased. At the initial pH 4.0 no biosynthesis of nicin was observed. Under the experimental conditions the antibiotic synthesis by tr. lactic started at the initial pH being equal to 4.5 and reached its maximum at pH 6.6.