Abstract: Red River Gum (Eucalyptus camaldulensis) is a tree
of the genus Eucalyptus widely distributed in Algeria and in the
world. The value of its aromatic secondary metabolites offers new
perspectives in the pharmaceutical industry. This strategy can
contribute to the sustainable development of our country. Preliminary
tests performed on the essential oil of Eucalyptus camendulensis
showed that this oil has antibacterial activity vis-à-vis the bacterial
strains (Enterococcus feacalis, Enterobacter cloaceai, Proteus
microsilis, Escherichia coli, Klebsiella pneumonia, and Pseudomonas
aeruginosa) and antifungic (Fusarium sporotrichioide and Fusarium
graminearum). The culture medium used was nutrient broth Muller
Hinton. The interaction between the bacteria and the essential oil is
expressed by a zone of inhibition with diameters of MIC indirectly
expression of. And we used the PDA medium to determine the fungal
activity. The extraction of the aromatic fraction (essentially oilhydrolat)
of the fresh aerian part of the Eucalyptus camendulensis
was performed by hydrodistillation. The average essential oil yield is
0.99%. The antimicrobial and fungal study of the essential oil and
hydrosol showed a high inhibitory effect on the growth of pathogens.
Abstract: Endophytic microorganisms are presented in plants of different families growing in the foothills and piedmont plains of Trans-Ili Alatau. It was found that the maximum number of endophytic micromycetes is typical to the Fabaceae family. The number of microscopic fungi in the roots reached (145.9±5.9)×103 CFU/g of plant tissue; yeasts - (79.8±3.5)×102 CFU/g of plant tissue. Basically, endophytic microscopic fungi are typical for underground parts of plants. In contrast, yeasts more infected aboveground parts of plants. Small amount of micromycetes is typical to inflorescence and fruits. Antagonistic activity of selected micromycetes against Fusarium graminearum, Cladosporium sp., Phytophtora infestans and Botrytis cinerea phytopathogens was detected. Strains with a broad, narrow and limited range of action were identified. For further investigations Rh2 and T7 strains were selected, they are characterized by a broad spectrum of fungicidal activity and they formed the large inhibition zones against phytopathogens. Active antagonists are attributed to the Rhodotorula mucilaginosa and Beauveria bassiana species.
Abstract: Toxic and bloom-forming cyanobacterium Microcystis
aeruginosa was exposed to antialgal allelochemical gramine (0, 0.5, 1,
2, 4, 8 mg·L-1), The effects of gramine on photosynthetic pigments
(lipid soluble: chlorophyll a and β-carotene; water soluble:
phycocyanin, allophycocyanin, phycoerythrin, and total phycobilins)
and absorption spectra were studied in order to identify the most
sensitive pigment probe implicating the crucial suppression site on
photosynthetic apparatus. The results obtained indicated that all
pigment parameters were decreased with gramine concentration
increasing and exposure time extending. The above serious bleaching
of pigments was also reflected on the scanning results of absorption
spectra. Phycoerytherin exhibited the highest sensitivity to gramine
added, following by the largest relative decrease. It was concluded that
gramine seriously influenced algal photosynthetic activity by
destroying photosynthetic pigments and phycoerythrin most sensitive
to gramine might be contributed to its placing the outside of
phycobilins.
Abstract: A three-year field experiment (2010-2012) was
conducted to determine the abundance of epiphytic and endophytic
filamentous fungi colonizing the grain of winter wheat cv. Bogatka.
Wheat spikes were protected with tebuconazole or chitosan at the
watery ripe stage. Untreated plants served as control. Tebuconazole
exerted an inhibitory effect primarily on F. culmorum and F.
graminearum, and its effectiveness was determined by the pressure
from pathogens that infected wheat spikes during the growing season.
Chitosan did not suppress the growth of Fusarium species and
Alternaria alternata.
Abstract: In this study, inhibition of Microcystis aeruginosa by
antialgal alleochemical gramine, was studied by analyzing algal
metabolic activity (represented by esterase and total dehydrogenase
activities) and cell ultrastructure (showing morphological and
ultrastructure alterations using transmission electron microscopy and
DNA ladder analysis). After gramine exposure, esterase and total
dehydrogenase activities were increased firstly but decreased later. In
contrast with the controls, the cells exposed to gramine showed
apparent ultrastructure alterations with thylakoids in breakage,
phycobilins in decrease, lipid and cyanophycin granules abundant
firstly but dissolved afterwards, DNA in fragementation. The
occurrence of increase of metabolic activity and specific granules
reflected that the resistance of cellular response to gramine was
initiated. DNA fragementation associated with the increase of
metabolic activity and specific granules hinted that gramine caused M.
aeruginosa cells to initiate some morphotype of programmed cell
death.