[The effect of high-molecular weight chitosans on the antioxidant and immune systems of the honeybee].

High-molecular weight chitosan (200 kDa, 75% deacetylated) and N-succinoyl chitosan (300 kDa, 75% deacetylated) were shown to have a preadaptive effect and increase the lifespan of honeybees due to the induction of protective antioxidant and immune mechanisms. Chitosan with a molecular weight of 200 kDa had a fungistatic effect on a pathogenic fungus that causes ascospherosis, a disease of bee larvae and pupae.

[Clinical effect of chitosan in bacterial vaginosis therapy].

AIM: Determination of antibacterial activity of acid-soluble chitosan in bacterial vaginosis therapy in women of reproductive age and comparison of therapy results of traditional scheme and local administration of acid-soluble chitosan. MATERIALS AND METHODS: Vaginal microflora of 76 gynecologic and obstetrical female patients (18-43 years of age) with bacterial vaginosis diagnosis was examined by using bacteriological method. Control group consisted of 30 practically healthy women. Sensitivity of 145 bacteria strains from 14 genera to 2% acid-soluble chitosan solution (200-250 kDa molecularweight) was determined by using agar diffusion method. RESULTS: During bacterial vaginosis members of the Gardnerella, Mobiluncus and Bacteroides genera dominated with a background reduction of lactobacilli quantity. An increase of population level of Staphylococcus, Enterococcus, Prevotella, Porphyromonas, Peptostreptococcus genera members, and Candida species was also observed. All the microorganisms were sensitive to 2% chitosan solution. Mycoplasma and Ureaplasma spp. were sensitive to chitosan in 82% of cases. Administration of chitosan in local therapy of vaginosis resulted in suppression of opportunistic microflora and clinical effect with a lack of adverse effects. CONCLUSION: Local administration of chitosan is perspective against bacterial vaginosis.

[The use of enzymatic preparation for the production of low molecular-weight chitosan from the king crab hepatopancrease].

This article describes the optimal conditions for the enzymatic hydrolysis of chitosan and its chemically-modified derivatives using the preparation extracted from the king crab hepatopancrease possessing pronounced hydrolythic activity. The following preparations were used: chitosan with a molecular weight of 100 kDa and an acetylation level of 0.15, carboxymethyl chitosan 200 kDa witih an extent of replacement of 0.23, and N-succinyl chitosan 390 kDa with an extent of replacement of 0.8. Low molecular-weight samples of chitosan and of its modified derivatives were obtained with the yields of 85, 55, and 80%, respectively. The conditions of the hydrolysis were as follows: an enzyme: substrate ratio of 1:200, 37 degrees C, and 20 h duration of hydrolysis.

[Derivatives of chitin and chitosan as elicitors of potato resistance to late blight]. / Proizvodnye khitina i khitozana kak élisitory fitoftoroustoichivosti kartofelia.

Water-soluble low-molecular-weight (3-10 kDa) chitosan obtained by enzymatic degradation of high-molecular-weight chitosan, as well as its deaminated derivatives, can be used as elicitors of late blight resistance in potato.