Biosynthesis of hydroxyphaseollin and related isoflavanoids in disease-resistant soybean hypocotyls

Phenylalanine-U-¹⁴C and isoliquiritigenin-9-¹⁴C were readily incorporated into the antifungal pterocarpan hydroxyphaseollin in soybean hypocotyls that were inoculated with incompatible strains of the phytopathogenic fungus Phytophthora megasperma var. sojae. Hydroxyphaseollin accounted for over half of the phenylalanine and isoliquiritigenin incorporated into ethyl acetate soluble compounds. Daidzein, coumestrol, and sojagol were identified as major compounds which accumulated coordinately with hydroxyphaseollin and contained significant amounts of radioactivity from the labelled isoflavanoid precursors. Hydroxyphaseollin was not present in healthy soybean plants and was not detected until ca. 16 hr after inoculation with the fungus. The pterocarpan then accumulated rapidly between 16 and 48 hr after inoculation, while the greatest accumulations of daidzein, coumestrol, and sojagol occurred between 48 and 72 hr after inoculation, when hydroxyphaseollin accumulation had ceased. Although soybean hypocotyls contained the anthocyanin malvin, neither this compound nor any other flavone pathway product was observed to accumulate after fungus-inoculation. The results therefore indicate that the accumulation of hydroxyphaseollin in fungus-inoculated soybean hypocotyls involves the activation of isoflavanoid biosynthesis with 'direction' of metabolic intermediates to biosynthesis of the pterocarpan.     

Effect of protease and helicase mutations on HCV NS3 activity

Hepatitis C virus (HCV) causes serious infections in the liver which may lead to liver cirrhosis and hepatocellular carcinoma. Non structural 3 (NS3) protein is one of the most important proteins of the virus which has protease and helicase activities. Protease activity has a crucial role in the replication and persistence of the virus. Site directed mutation was carried out in the protease region of one NS3 and another site directed mutation in the helicase region of another NS3. The expression of both mutated NS3 was compared with wild NS3. Expression of the three different NS3 types was confirmed by in situ staining and western blotting using an anti-NS3 antibody and correlated with a reduced antiviral response after treatment with interferon-α. Mutation analysis showed that the NS3 protease activity andnot the NS3 helicase was essential for the inhibition of the interferon-α response.     

Crystal structure of human PACRG in complex with MEIG1 reveals roles in axoneme formation and tubulin binding

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Biocontrol of wilt disease complex of pea using Pseudomonas fluorescens and Rhizobium sp.

Biocontrol of wilt disease complex of pea caused by the root-knot nematode Meloidogyne incognita and Fusarium oxysporum f. sp. pisi was studied on pea (Pisum sativum L.) using plant growth-promoting rhizobacterium Pseudomonas fluorescens and root nodule bacterium Rhizobium sp. Inoculation of M. incognita and F.oxysporum alone caused significant reductions in plant growth over un-inoculated control. Reduction in plant growth caused by M. incognita was statistically equal to that caused by F. oxysporum. Inoculation of M. incognita plus F. oxysporum together caused a greater reduction in plant growth than the sum of damage caused by these pathogens singly. Inoculation of P. fluorescens and Rhizobium sp. individually or both together increased plant growth in pathogen inoculated and un-inoculated plants. Inoculation of P. fluorescens to pathogen-inoculated plants caused a greater increase in plant growth than caused by Rhizobium sp. Application of Rhizobium plus P. fluorescens caused a greater increase in plant growth than caused by each of them singly. Inoculation of P.fluorescens caused higher reduction in galling and nematode multiplication than caused by Rhizobium sp. Use of Rhizobium plus P. fluorescens caused higher reduction in galling and nematode multiplication than their individual inoculation. Plants inoculated with both pathogens plus Rhizobium showed less nodulation than plants inoculated with single pathogen plus Rhizobium. Inoculation of Rhizobium plus P. fluorescens resulted in higher root-nodulation than inoculated only with Rhizobium. Wilting indices were 4 and 5, respectively, when plants were inoculated with F. oxysporum and F. oxysporum plus M. incognita. Wilting indices were reduced maximum to 1 and 2, respectively, when plants inoculated with F.oxysporum and plants with both pathogens were treated with P. fluorescens plus Rhizobium.     

Interactions of Ralstonia solanacearum and Pectobacterium carotovorum with Meloidogyne incognita on potato

Effect of interactions of Meloidogyne incognita with Ralstonia solanacearum and interaction of M. incognita with Pectobacterium carotovorum were studied in sequential and simultaneous inoculations on potato (Solanum tuberosum). Inoculation of M. incognita caused a lesser reduction in plant growth than caused by R. solanacearum. Inoculation of M. incognita plus R. solanacearum caused a greater reduction in plant growth than the damage caused by either pathogen. Inoculation of M. incognita prior to R. solanacearum resulted in a greater reduction in plant growth than R. solanacearum was inoculated prior to M. incognita. However, inoculation of M. incognita or P. carotovorum caused similar reduction in plant growth. Inoculation of P. carotovorum prior to M. incognita caused lesser reduction in plant growth than simultaneous inoculation of both pathogens. Inoculation of M. incognita caused galling in potato roots but the size of galls was small. Inoculation of P. carotovorum or R. solanacearum with M. incognita had adverse effect on galling and nematode multiplication. Wilting or soft rot index was 3 when R. solanacearum or P. carotovorum was inoculated alone. In other treatments, where R. solanacearum or P. carotovorum was inoculated with M. incognita, wilting or soft rot indices were 5.     

Laboratory studies on extracts of Melia fruit and Neem fruit on B. brassicae,B. tabaci and their predators and parasites

Abstract

The biological effect of plant extracts on the two predators C. carnea and C. undecimpunctata was studied in the laboratory. Treated B. brassicae was offered to the newly hatched larvae of the two predators. The rate of prey consumption and duration of the larval instars of the two predators were slightly affected as a result of the treatments of the plant extracts. Adults of the aphid parasite D. Rapae and the whitefly parasite E. Mundus were exposed to the plant extracts via feeding on treated honey droplets or parasitized treated hosts. Mortality percentages of D. Rapae fed on honey contaminated with plant extracts were 50 and 80% for extracts of Melia fruits in ethanol and in petroleum ether, respectively. Mortalities in parasites developed in hosts treated with plant extracts of Neem fruits in ethanol and Melia flowers in petroleum ether in were 33.3 and 81.5%, respectively. Similar results were obtained when E. Mundus received the same treatments of the plant extracts.     

Breast-Feeding Protects Infantile Diarrhea Caused by Intestinal Protozoan Infections

This study investigated the effect of breast-feeding in protection against protozoan infection in infants with persistent diarrhea. Infants were classified into 2 groups; 161 breast-fed infants and the same number of non-breast-fed infants. Microscopic examinations of stool were done for detection of parasites and measuring the intensity of infection. Moreover, serum levels of IgE and TNF-α were measured by ELISA. Cryptosporidium spp., Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Blastocystis sp. were demonstrated in infants with persistent diarrhea. The percentage of protozoan infections was significantly lower in breast-fed infants than that in the non-breast-fed infants. The levels of IgE and TNF-α were significantly lower in the breast-fed group than in the non-breast-fed group. There were significant positive associations between the serum levels of IgE and TNF-α and the intensity of parasite infection in the breast-fed group. It is suggested that breast-feeding has an attenuating effect on the rate and intensity of parasite infection.     

PTPN22 gene polymorphism in Egyptian alopecia areata patients and its impact on response to diphencyprone immunotherapy

PTPN22 1858C>T gene polymorphism has been associated with several autoimmune disorders including alopecia areata. The aim of the current study was to investigate the effect of the inherited genetic polymorphism 1858C>T of PTPN22 gene on the predisposition to severe forms of alopecia areata and its effect on the response to DPC treatment. To achieve our aim, PTPN22 1858C>T genotyping was performed by PCR-based restricted fragment length polymorphism (PCR-RFLP) analysis. The study included 103 Egyptian patients with extensive alopecia areata treated by DPC. Hundred healthy age and sex matched blood donors were included in the current study as a control group. Results of genotyping showed that PTPN22 CT and TT mutant genotypes were significantly higher in AA patients compared to controls and conferred increase risk of AA (OR = 2.601, 95% CI = 1.081–6.255). Statistical comparison between AA patients with wild and mutant genotypes revealed that the duration of the illness was significantly longer in those harboring the mutant genotypes. Moreover, the association of other autoimmune diseases as atopy and diabetes mellitus was higher in patients with mutant genotypes. Furthermore, PTPN22 1858C>T genetic polymorphism did not affect the patients' response to DPC immunotherapy.