Bhendi yellow vein mosaic disease in India is caused by association of a DNA Beta satellite with a begomovirus.
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Yellow vein mosaic disease is the major limitation in the production of bhendi or okra (Abelmoschus esculentus), an important vegetable crop of India. This disease is caused by a complex consisting of the monopartite begomovirus Bhendi yellow vein mosaic virus (BYVMV, family: Geminiviridae) and a small satellite DNA beta component. BYVMV can systemically infect bhendi upon agroinoculation but produces only mild leaf curling in this host. DNA beta induces typical symptoms of bhendi yellow vein mosaic disease (BYVMD) when co-agroinoculated with the begomovirus to bhendi. The DNA beta component associated with BYVMD has a number of features in common with those reported for ageratum yellow vein disease and cotton leaf curl disease. BYVMV represents a new member of the emerging group of monopartite begomoviruses requiring a satellite component for symptom induction. (+info)
Determination of enzymes from Colletotrichum sp. AHU9748 essential for lepidimoide production from okra polysaccharide.
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The allelopathic substance lepidimoide (Lp), which exhibits multiple functions in the growth and development of plants, was produced by Colletotrichum sp. AHU9748 from okra polysaccharide. Okra polysaccharide has the repeating structure (1-->4)-O-alpha-(d-galactopyranosyluronic acid)-(1-->2)-O-alpha-l-rhamnopyranose in its hexasaccharide repeating unit of its main chain. To determine the enzymes essential for Lp production, the supernatant of a culture broth was fractionated by repeated column chromatographies to identify two serial fractions responsible for Lp production and non-Lp production by measuring Lp production together with beta-galactosidase (beta-gal), rhamnogalacturonan lyase (RG-lyase) and acetylesterase (AE) activities, which we hypothesized to be necessary for Lp production from the structure of Lp. We confirmed the presence of these three enzymatic activities in the highest-Lp-producing fraction. The addition of purified RG-lyase to fractions producing no or a small amount of Lp demonstrated that beta-gal and RG-lyase activities are necessary for Lp production. The N-terminal amino acid sequences of the three separated proteins on SDS-PAGE confirmed the presence of enzymes identical to beta-gal, RG-lyase and AE in the Lp-producing fractions. (+info)
In vivo and in vitro antiviral activity of hyperoside extracted from Abelmoschus manihot (L) medik.
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AIM: To assess the anti-hepatitis B virus (HBV) effect of hyperoside extracted from Abelmoschus manihot (L) medik. METHODS: The human hepatoma Hep G2.2.15 cell culture system and duck hepatitis B virus (DHBV) infection model were used as in vivo and in vitro models to evaluate the anti-HBV effects. RESULTS: In the cell model, the 50% toxic concentration of hyperoside was 0.115 g/L; the maximum nontoxic concentration was 0.05 g/L. On the maximum nontoxic concentrations, the inhibition rates of hyperoside on HBeAg and HBsAg in the 2.2.15 cells were 86.41% and 82.27% on d 8, respectively. In the DHBV infection model, the DHBV-DNA levels decreased significantly in the treatment of 0.05 g x kg(-1 ) x d(-1 ) and 0.10 g x kg(-1) x d(-1) dosage groups of hyperoside (P<0.01). The inhibition of the peak of viremia was at the maximum at the dose of 0.10 g x kg(-1 ) x d(-1) and reached 60.79% on d 10 and 69.78% on d 13, respectively. CONCLUSION: These results suggested that hyperoside is a strong inhibitor of HBsAg and HBeAg secretion in 2.2.15 cells and DHBV-DNA levels in the HBV-infected duck model. (+info)
Protective effect of total flavones of Abelmoschus manihot L. Medic against poststroke depression injury in mice and its action mechanism.
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Simultaneous determination of seven active flavonols in the flowers of Abelmoschus manihot by HPLC.
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A high-performance liquid chromatography method is developed for the simultaneous quantification of seven flavonols, namely quercetin-3-O-robinobioside, hyperin, isoquercetin, hibifolin, myricetin, quercetin-3'-O-glucoside, and quercetin, in the flower of Abelmoschus manihot. These seven flavonols are selected as chemical markers because they are the major pharmacologically active constituents in the flower. The method involves the use of a Thermo ODS-2HYEPRSIL reversed-phase column (5 microm, 250 x 4.6 mm) at 25 degrees C with a mixture of acetonitrile and aqueous H(3)PO(4) as the mobile phase and detection at 370 nm. The recovery of the method is 94.31-107.08% with an RSD < or = 3.14% and the linearity (r(2) > 0.9996) is obtained for all the flavonoids. The current assay method can be readily utilized for the determination of the flavonols present in the flower and is considered to be suitable for the quality control of A. manihot samples. The comparison of flowers collected from nine locations shows that flavonoid glucoside is more stable than aglycon in the flower. This is the first study that analyzes the stability of flavonoids in the flower of A. manihot. This research also provides important evidence that the flower is a potentially abundant resource for obtaining hibifolin. (+info)
Molecular diversity of cotton leaf curl Gezira virus isolates and their satellite DNAs associated with okra leaf curl disease in Burkina Faso.
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Oral sustained release tablets of zidovudine using binary blends of natural and synthetic polymers.
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Oral sustained release matrix tablets of zidovudine (ZDV) were prepared using different types, proportions and blends of carbopol 71G (C71) and a plant gum obtained from Abelmoschus esculentus (AEG). The effect of various formulation factors like polymer proportion, polymer type and pH of the dissolution medium on the in vitro release of the drug was studied, using the half change technique, in 900 ml of dissolution medium, at 100 rpm. Release kinetics were analyzed using Zero-order, Higuchi's square-root and Ritger-Peppas' empirical equations. In vitro release performance as revealed by the time taken for 70% of the drug to be released (t70%), showed that the release rate decreased with increase in polymer proportion. Matrix tablets containing 10 and 20% AEG were found to exhibit immediate-release characteristics. Matrix tablets containing 30% AEG showed t70% value of 204 min and extended the release up to 5 h, while matrix tablets containing 30% carbopol showed t70% value of 234 min and extended the release up to 6 h. Three blends of AEG and C71 at the ratio of 1:2, 2:1 and 1:3 showed t70% values of 132, 312 and 102 min respectively and extended the release up to 8 h. Mathematical analysis of the release kinetics indicated that the nature of drug release from the matrix tablets followed Fickian and anomalous release. Drug release from matrix tablets of zidovudine containing blends of AEG and C71 demonstrates the advantage of blending a natural and synthetic polymer over single polymer use. (+info)