Role of prodigiosin and chitinases in antagonistic activity of the bacterium Serratia marcescens against the fungus Didymella applanata.

The molecular features of antagonism of the bacterium Serratia marcescens against the plant pathogenic fungus Didymella applanata have been studied. The chitinases and the red pigment prodigiosin (PG) of S. marcescens were isolated and characterized. Specific antifungal activity of the purified PG and chitinases against D. applanata was tested in vitro. The antagonistic properties of several S. marcescens strains exhibiting different levels of PG and chitinase production were analyzed in vitro with regard to D. applanata. It was found that the ability of S. marcescens to suppress the vital functions of D. applanata depends mainly on the level of PG production, whereas chitinase production does not provide the bacterium with any competitive advantage over the fungus.

[Effect of a preparation from Chaetomium fungi on the growth of phytopathogenic fungi].

We studied the fungicidal activity of a biological preparation from the fungi of the genus Chaetomium against soil phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum. The inhibitory effect of the preparation under study depended on its concentration, duration of storage, and growth characteristics of pure cultures of the phytopathogens. The highest (98.8%) inhibitory activity was observed on day 3 of the interaction with Rhizoctonia solani. After a 2-year storage, this preparation was capable of inhibiting the growth of the phytopathogens only at high doses. The preparation precluded the development of bare patch and increased the productivity of potato plants. The preparation may serve as an alternative to chemical fungicides for plant protection.

[Evaluation of the effects of biological preparations on phytopathogenic fungi Didymella applanata and Botrytis cinerea]. / Otsenka biologicheskikh preparatov v otnoshenii fitopatogennykh gribkov Didymella applanata i Botrytis cinerea.

Fungicidal and fungistatic effects of biological preparations involving bacteria of the genera Pseudomonas and Bacillus and fungi of the genus Chaetomium on phytopathogenic fungi Didymella applanata and Botrytis cinerea were evalauated. All the biological preparations under study inhibited the growth of colonies of the fungi; however, the degree of the inhibition depended on the nature of each particular microorganism and the concentration of each particular preparation. The preparation containing Bacillus subtilis at a concentration of 0.2% effected maximum suppression of B. cinerea (the diameter of the colonies decreased sevenfold). The preparations containing bacteria of the genus Pseudomonas and fungi of the genus Chaetomium were most efficient in suppressing D. applanata. The preparations containing B. subtilis and Chaetomium spp. showed promise as agents against simultaneous development of spur blight and Botrytis blight.

[Protein metabolic change in the tissues of Aporia crataegi L. under the action of the nuclear polyhedrosis virus]. / Izmenenie belkovogo obmena v tkaniakh Aporia crataegi L. pod deistviem virusa iadernogo poliédroza.

Changes in protein metabolism in the hemolymph, fat body, intestine, and gonads of Aporia crataegi L. caterpilars under the influence of nuclear polyhedrosis virus were studied. Electrophoresis in polyacrylamide gel was used to study acid and basic proteins of insect tissues normally and after virus infection. The virus infection was shown to result in sharp changes of the protein spectrum of various tissues and organs, particularly 3 days after infection. The main changes consisted in the loss of coordination of age cellular protein synthesis and formation of new virus-specific proteins.