Fungal endophytes: unique plant inhabitants with great promises

Fungal endophytes residing in the internal tissues of living plants occur in almost every plant on earth from the arctic to the tropics. The endophyte–host relationship is described as a balanced symbiotic continuum ranging from mutualism through commensalism to parasitism. This overview will highlight selected aspects of endophyte diversity, host specificity, endophyte–host interaction and communication as well as regulation of secondary metabolite production with emphasis on advanced genomic methods and their role in improving our current knowledge of endophytic associations. Furthermore, the chemical potential of endophytic fungi for drug discovery will be discussed with focus on the detection of pharmaceutically valuable plant constituents as products of fungal biosynthesis. In addition, selected examples of bioactive metabolites reported in recent years (2008–2010) from fungal endophytes residing in terrestrial plants are presented grouped according to their reported biological activities.     

Pathogenicity of Bacillus Strains to Cotton Seedlings and Their Effects on Some Biochemical Components of the Infected Seedlings

Pathogenicity of eight Bacillus strains to seedlings of four cotton cultivars was evaluated under greenhouse conditions. Each of the tested cultivars was individually treated with powdered inoculum of each bacterial strain. Untreated seeds were planted as control treatments in autoclaved soil. Effects of the tested strains on levels and activities of some biochemical components of the infected seedlings were also assayed. The biochemical components included total soluble sugars, total soluble proteins, total free amino acids, peroxidase, polyphenol oxidase, phenols, and lipid peroxidation. ANOVA showed that Bacillus strain (B) was a very highly significant source of variation in damping-off and dry weight. Cotton cultivar (V) was a nonsignificant source of variation in damping-off while it was a significant source of variation in dry weight. B × V interaction was a significant source of variation in damping- off and a nonsignificant source of variation in dry weight. Bacillus strain was the most important source of variation as it accounted for 59.36 and 64.99% of the explained (model) variation in damping-off and dry weight, respectively. The lack of significant correlation between levels and activities of the assayed biochemical components and incidence of damping-off clearly demonstrated that these biochemical components were not involved in the pathogenicity of the tested strains. Therefore, it was hypothesized that the pathogenicity of the tested strains could be due to the effect of cell wall degrading enzymes of pathogenic toxins. Based on the results of the present study, Bacillus strains should be considered in studying the etiology of cotton seedling damping-off.     

Synthesis of Some New Pyrazoline-Based Thiazole Derivatives and Evaluation of Their Antimicrobial,Antifungal, and Anticancer Activities

Russian Journal of Bioorganic Chemistry - 3-(2-Thienyl)-5-aryl-1-thiocarbamoyl-2-pyrazolines were reacted with chloroacetone derivatives and hydrazonyl chloride derivatives in ethanol to afford the...     

Influence of interleukin-2 and interferon-gamma in murine schistosomiasis

Schistosoma mansoni-infected mice were administered at the time of parasite residency in the lung with recombinant murine interleukin (IL)-2 or interferon-gamma (IFN-gamma), to evaluate the impact of cytokines in host responses to primary schistosomiasis. S. mansoni lung-stage schistosomula did not affect plasma lipids levels in BALB/c, while elicited significant (p<0.05) increase in free fatty acids (FA) and decrease in cholesterol plasma levels in C57BL/6 and CD1 mice, and stimulated expression of mRNA for Th2 cytokines in BALB/c and Th1 cytokines in C57BL/6 and CD1 mice. Production of specific antibodies was negligible in the 3 strains. Interleukin-2 treatment elicited significant (p<0.001) decrease in triglycerides (TG) in CD1, and decrease in TG and cholesterol plasma levels and down-regulation of TNF-alpha mRNA expression in C57BL/6 mice. Induction of type 2 cytokines and/or IFN-gamma mRNA expression did not lead to increase in percentage of specific antibody responders in any mouse strain. Exogenous IL-2-related reduction in cholesterol plasma levels and TNF-alpha mRNA expression in C57BL/6 mice was associated with significant (p<0.05) decrease in adult worm recovery and egg count. Treatment with IFN-gamma elicited significant (p<0.05) free FA plasma levels increase in BALB/c and C57BL/6 and decrease in CD1 mice. Expression of type 2 cytokines mRNA was stimulated in BALB/c and CD1 mice, yet was not accompanied with increase in humoral responses. Exogenous IFN-gamma-related reduction in free FA plasma levels and IFN-gamma mRNA response, and up-regulation of TNF-alpha mRNA expression in CD1 mice were associated with significant increase in adult worm burden and egg load. The data were discussed in an attempt to define host factors predictive of resistance to schistosome infection.     

Increased DNA damage in children caused by passive smoking as assessed by comet assay and oxidative stress

The present study aimed to evaluate the association between the environmental tobacco smoke (ETS) and DNA damage in relation to oxidative stress (OS) in children. Sixty-four children of age 1-8 years, selected from the outpatient clinic of Mansoura University Children Hospital were divided into two groups (23 children/group) based on high (>20 cigarettes/day) or low (<20 cigarettes/day) exposure to ETS at home. Twenty symptom-free children with normal cotinine level and with no exposure to ETS were recruited as controls. The comet assay was used to quantify the level of DNA damage in lymphocytes isolated from all children. Spectrophotometric methods were used to assess the serum level of malondialdehyde (MDA) and activity of glutathione peroxidase (GSH-Px) in erythrocytes. Also, serum level of tocopherol fractions (alpha, gamma, delta) was assessed by high performance liquid chromatography (HPLC). Children exposed to ETS exhibited retarded growth, more chest problems, and gastroenteritis than the control. A significant increase in mean comet tail length indicating DNA damage was observed in ETS-exposed children (P<0.001) compared to controls. ETS-exposed children had significantly (P<0.001) higher MDA level paralleled with significant (P<0.001) decrease in the level of GSH-Px and tocopherol fractions compared with controls. The GSH-Px activity and tocopherol levels were inversely correlated with the increase of ETS exposure. These results show that inhalation of ETS is associated with an increase in the level of oxidants and a simultaneous decrease in the level of antioxidants in the children's blood. This status of oxidant-antioxidant imbalance (OS) may be one of the mechanisms leading to DNA damage detected in lymphocytes of ETS-exposed children. In conclusion, the present study gives an indication of an association between DNA damage and ETS exposure in children.     

Media derived from brown seaweeds <Emphasis Type="Italic">Cystoseira myriophylloides</Emphasis> and <Emphasis Type="Italic">Fucus spiralis</Emphasis> for in vitro plant tissue culture

In the present study, the effect of seaweed extract (SE) from Fucus spiralis (Fs), Cystoseira myriophylloides (Cm) and Laminaria digitata (Ld) on in vitro plant tissue culture was examined. Combination of 25?% of SE from Cm with 25?% of MS medium increased adventitious shoot regeneration from Nicotiana benthamiana leaf discs explants by 620?%, when compared to the conventional regeneration medium. Similarly SE from Fs and Ld enhanced regeneration by about 500?%. However, when increasing SE to 50?%, only Cm significantly enhanced shoot regeneration. The effect of SE was also evaluated on in vitro micropropagation of N. benthamiana, grape, plum and apricot by assessing shoot length, number of leaves and internodes. When used alone but at lower concentrations (2.5 and 12.5?%), SE from Fs and Cm resulted in at least the same efficacy as MS alone for micropropagation of N. benthamiana shoots. However, for micropropagation of grapevine, plum and apricot woody plants, a combination of 50?% of SE from Cm or Fs with 50?% of their conventional micropropagation media was necessary. Rooting was also enhanced in N. benthamiana and grapevine, and was correlated with their higher concentrations of indole acetic acid when compared to SE from Ld. This finding, in addition to mineral analysis data, suggests that SE of Fs and Cm contain necessary nutrients and growth regulators to allow their use as medium for in vitro plant culture.     

Cyclin D1 gene amplification in proliferating haemangioma

Cyclin D1 gene amplification has been reported to promote abnormal endothelial cell proliferation and angiogenesis; these findings constantly present in proliferating haemangiomas. The present study was conducted to evaluate cyclin D1 gene amplification by fluorescence in situ hybridization analysis in tissue biopsies of 22 proliferating haemangiomas from 20 infants. Two significant correlations of cyclin D1 gene amplification with the early onset and the duplication of proliferating haemangiomas have been observed. Moreover, a significant correlation (P≤0.05) has been found between the treatment parameters of proliferating haemangiomas with the amplified versus the normal cyclin D1 gene. Proliferating haemangiomas with the amplified cyclin D1 gene required more frequent flashlamp pulsed dye laser treatment sessions at the maximum dosimetry and more frequent intralesional steroid injections at the maximum dose/injection but treatment outcomes were limited. The more frequent post-treatment complications among proliferating haemangiomas with cyclin D1 gene amplification might be attributable not only to the associated more aggressive natural course, but also to the higher treatment parameters needed for effective treatment. Within the limitations of the present study, cyclin D1 gene amplification was seen for the first time in proliferating haemangiomas. We have found that the amplification of the cyclin D1 gene can predict the more aggressive natural course of proliferating haemangiomas and the limited outcome and higher incidence of complications after non–excision treatment modalities. The present findings reflect the possible usefulness of antisense cyclin D1 to improve the therapeutic outcome of proliferating haemangiomas.