The DNA beta satellite component associated with ageratum yellow vein disease encodes an essential pathogenicity protein (betaC1). (1/8)

Ageratum yellow vein disease (AYVD) is caused by the geminivirus ageratum yellow vein virus (AYVV) and an associated DNA beta satellite. We have mapped a DNA beta transcript to a highly conserved open reading frame (betaC1 ORF). The most abundant transcript 5'-terminus is located 8 bases upstream of the betaC1 ORF putative initiation codon while the transcript terminates at multiple sites downstream from the putative termination codon. Disruption of betaC1 protein expression by the introduction of an internal nonsense codon prevented infection of the AYVV-satellite complex in ageratum and altered the phenotype in Nicotiana benthamiana to that produced by AYVV alone although the mutant was maintained in systemically infected tissues. Modification of the putative initiation codon to a nonsense codon produced an intermediate phenotype in N. benthamiana and a mild yellow vein phenotype in ageratum, suggesting that betaC1 protein expression could be initiated from an alternative site. N. benthamiana plants containing a dimeric DNA beta transgene produced severe developmental abnormalities, vein-greening, and cell proliferation in the vascular bundles. Expression of betaC1 protein from a potato virus X (PVX) vector also induced abnormal plant growth. Our results demonstrate that the satellite encodes at least one protein that plays a major role in symptom development and is essential for disease progression in ageratum, the natural host of the AYVD complex.  (+info)

Screening of crude extracts of six medicinal plants used in South-West Nigerian unorthodox medicine for anti-methicillin resistant Staphylococcus aureus activity. (2/8)

BACKGROUND: Six Nigerian medicinal plants Terminalia avicennioides, Phylantus discoideus, Bridella ferruginea, Ageratum conyzoides, Ocimum gratissimum and Acalypha wilkesiana used by traditional medical practitioners for the treatment of several ailments of microbial and non-microbial origins were investigated for in vitro anti-methicillin Resistant Staphylococcus aureus (MRSA) activity. METHODS: Fresh plant materials were collected from the users. Water and ethanol extracts of the shredded plants were obtained by standard methods. The Bacterial cultures used were strains of MRSA isolated from patients. MRSA was determined by the reference broth microdilution methods using the established National Committee for Clinical Laboratory Standards break points. Staphylococcus aureus NCIB 8588 was used as a standard strain. Susceptibility testing and phytochemical screening of the plant extracts were performed by standard procedures. Controls were maintained for each test batch. RESULTS: Both water and ethanol extracts of T. avicennioides, P. discoideus, O. gratissimum, and A. wilkesiana were effective on MRSA. The Minimum Inhibition Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the ethanol extracts of these plants range from 18.2 to 24.0 mcg/ml and 30.4 to 37.0 mcg/ml respectively. In contrast, MIC range of 30.6 to 43.0 mcg/ml and 55.4 to 71.0 mcg/ml were recorded for ethanol and water extracts of B. ferruginea, and A. conyzoides respectively. Higher MBC values were obtained for the two plants. These concentrations were too high to be considered active in this study. All the four active plants contained at least trace amount of anthraquinones. CONCLUSION: Our results offer a scientific basis for the traditional use of water and ethanol extracts of A. wilkesiana, O. gratissimum, T. avicennioides and P. discoideus against MRSA-associated diseases. However, B. ferruginea and A. conyzoides were ineffective in vitro in this study; we therefore suggest the immediate stoppage of their traditional use against MRSA-associated diseases in Lagos, Nigeria.  (+info)

Replication promiscuity of DNA-beta satellites associated with monopartite begomoviruses; deletion mutagenesis of the Ageratum yellow vein virus DNA-beta satellite localizes sequences involved in replication. (3/8)

 (+info)

Hypoglycaemic and antihyperglycaemic activity of Ageratum conyzoides L. in rats. (4/8)

The hypoglycaemic and antihyperglycaemic properties of the aqueous extracts of the leaves of Ageratum conyzoides L. were evaluated in normoglycemic and in streptozotocin-induced diabetic rats, in order to validate its use in folk medicine. Tested animals were given the aqueous extracts of the plant at the doses of 100, 200 and 300mg/kg. These doses were tested also on glucose loaded normal male rats (Oral Glucose Tolerance Test). Of all the doses, the aqueous extracts at 200 and 300mg/kg showed statistically significant hypoglycaemic and antihyperglycaemic activities. For the oral glucose tolerance test, 100mg/kg dose only attenuated significantly the rise of blood glucose in normal fasted rats. Consequently, these results confirmed the hypoglycaemic properties of the leaves of Ageratum conyzoides.  (+info)

Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China. (5/8)

 (+info)

Schistosomicidal activity of the essential oil of Ageratum conyzoides L. (Asteraceae) against adult Schistosoma mansoni worms. (6/8)

 (+info)

Hypoglycaemic activity of Commelina africana and Ageratum conyzoides in relation to their mineral composition. (7/8)

 (+info)

Effects of organic extracts of six Bangladeshi plants on in vitro thrombolysis and cytotoxicity. (8/8)

 (+info)