ABSTRACT
Mycological analysis throughout the vegetation period of potato (Solanum tuberosum) made it possible to study in detail the structure of micromycete community, to determine typical dominant (frequency, more than 60%), typical common (frequency, 30 to 60%), typical rare (frequency, 10 to 30%), and casual (frequency, less than 10%) species and to estimate changes in the microorganism community caused by plant protection preparations with different mechanisms of action. It was shown that, as a result of occurrence of resistant forms, synthetic preparations against fungal pathogens of potato (such as TMTD, Ridomil gold MC, and Cupricol) were only slightly more effective than biological preparations (Trichodermin and AgroChit), with the former considerably changing the natural saprophytic mycological community. An increase in the soil pool of Trichoderma harzianum as a result of application of a biological preparation based on this antagonistic fungus correlated with its effectiveness against the soil pathogen Fusarium sp., which causes root rots. A chitosan-based elicitor preparation more effectively suppressed the development of early (Alternaria sp. and Macrosporium sp.) and late (Phytophthora sp.) blights of leaves and had a weaker effect on the soil microflora.
Subject(s)
Biological Products/pharmacology , Fungicides, Industrial/pharmacology , Plant Diseases/microbiology , Soil Microbiology , Solanum tuberosum/microbiology , Alanine/analogs & derivatives , Alanine/pharmacology , Alternaria/drug effects , Alternaria/growth & development , Fusarium/drug effects , Fusarium/growth & development , Phytophthora/drug effects , Phytophthora/growth & development , Thiram/pharmacology , Trichoderma/metabolism , Trichodermin/pharmacologyABSTRACT
The procedure of isolation of chitin, chitosan, and water-soluble low-molecular-weight chitin from the corpses of bees was developed. This procedure included deproteinization of the corpses of bees, discoloration of the chitin-melanin complex, deacetylation, and enzymatic hydrolysis of chitosan.
Subject(s)
Chitin/analogs & derivatives , Chitin/isolation & purification , Acetylation , Animals , Bees , ChitosanABSTRACT
Chitin isolated enzymatically from Antarctic krill shells was dissolved in aqueous NaOH by freezing and thawing to create homogenous conditions. Deacetylation was performed at room temperature or heating. The degree of deacetylation, molecular weight, and dynamic viscosity of solutions were estimated in chitosan samples. Deacetylation of chitin under homogenous conditions was optimized. Chitosans with molecular weights of 180-220 and 250-300 kDa were obtained from the chitins of Antarctic krill and Northern shrimps, respectively.
