ABSTRACT
Background & objectives: The susceptibility of the mosquito to the invading pathogen is predominantly dictated by the complex interactions between the mosquito midgut and the surface proteins of the invading pathogen. It is well documented that the midgut microbiota plays an important role in determining the susceptibility of the mosquito to the pathogen. In the present study, we investigated the influence of Serratia odorifera, an endogenous cultivable midgut inhabitant of Aedes aegypti on the chikungunya virus (CHIKV) susceptibility to this mosquito. Methods: Ae. aegypti females free of gutflora were co-fed with CHIKV and either of the two midgut inhabitants namely, S. odorifeara and Microbacterium oxydans. CHIKV dissemination was checked on 10th day post feeding (DPF) using indirect immunoflurescence assay and plaque assay. CHIKV interacting proteins of the mosquito midgut were identified using virus overlay protein binding assay and MALDI TOF/TOF analysis. Results: The observations revealed that co-feeding of S. odorifera with CHIKV significantly enhanced the CHIKV susceptibility in adult Ae. aegypti, as compared to the mosquitoes fed with CHIKV alone and CHIKV co-fed with another midgut inhabitant, M. oxydans. Virus overlay protein binding assay (VOPBA) results revealed that porin and heat shock protein (HSP60) of Ae. aegypti midgut brush border membrane fraction interacted with CHIKV. Interpretation & conclusions: tThe results of this study indicated that the enhancement in the CHIKV susceptibility of Ae. aegypti females was due to the suppression of immune response of Ae. aegypti as a result of the interaction between S. odorifera P40 protein and porin on the gut membrane.
ABSTRACT
Lichens are self-sufficient symbioses between an alga and a fungus. In the present study, we have determined total phenolic content, antimicrobial and antioxidant efficacy of a macrolichen Usnea pictoides G.Awasthi (Parmeliaceae) collected at Mullayanagiri, Western Ghats of Chikmagalur, Karnataka, India. The lichen was powdered and extracted sequentially using solvents of increasing polarity viz., petroleum ether, chloroform, ethyl acetate and methanol. Total phenolic content of solvent extracts was estimated by Folin-Ciocalteau reagent method. Antimicrobial activity of solvent extracts was tested against two bacteria viz., Staphylococcus aureus and Pseudomonas aerugionsa and two fungi viz., Candida albicans and Cryptococcus neoformans by Agar well diffusion assay. Antioxidant activity of solvent extracts was determined by DPPH free radical scavenging assay and Ferric reducing assay. Thin layer chromatogram showed the presence of usnic acid. The total phenolic content was highest in methanol extract followed by ethyl acetate, chloroform and petroleum ether extracts. S. aureus and C. neoformans showed high susceptibility to solvent extracts among bacteria and fungi. A dose dependent scavenging of DPPH radicals by solvent extracts was observed. The scavenging potential of methanol extract was higher than other extracts. In ferric reducing assay, methanol extract showed stronger reducing power than other extracts. Overall, extracts containing high phenolic contents exhibited stronger antioxidant activity. The inhibitory potential of the lichen extracts might be attributed to the presence of usnic acid. The radical scavenging and ferric reducing potential of solvent extracts could be attributed to the phenolic compounds. A positive correlation was observed between total phenolic content and the antioxidant activity of lichen extracts. The lichen U. pictoides can be a potential candidate for the development of bioactive agents.
ABSTRACT
The present study was conducted to estimate total phenolic and flavonoid content and to determine anticariogenic efficacy of methanol extract of Gnidia glauca (Fresen.) Gilg (Thymelaeaceae), Pothos scandens L. (Araceae) and Elaegnus kologa Schlecht (Elaeagnaceae) leaves. Total phenolic and flavonoid content of leaf extracts was determined by Folin-Ciocalteau method and Aluminium chloride colorimetric estimation method respectively. Anticariogenic activity of leaf extracts was assessed against 13 clinical isolates of Streptococcus mutans by Agar well diffusion technique. The contents of total phenolics and flavonoids were higher in G. glauca followed by P. scandens and E. kologa. The extract of G. glauca showed greater inhibition of cariogenic isolates than P. scandens and E. kologa as revealed by wider inhibition zones. The study revealed a correlation between the amount of phenolics and flavonoids present in the extracts and the anticariogenic activity of the extracts. The plants used in this study could be used against dental caries.
ABSTRACT
The methylation status of the nuclear DNA from a mealybug, a Planococcus species, has been studied. Analysis of this DNA by High Performance Liquid Chromatography and Thin Layer Chromatography revealed the presence of significant amounts of 5- methylcytosine. Since analysis of DNA methylation using the Msp I/Hpa II system showed only minor differences in susceptibility of the DNA to the two enzymes, it seemed possible that 5-methylcytosine (5mC) occurred adjacent to other nucleotides in addition to its usual position, next to guanosine. This was verified by dinucleotide analysis of DNA labelled in vitro by nick translation. These data show that the total amount of 5-methylcytosine in this DNA is slightly over 2.3 mol %, of which 0.61% occurs as the dinucleotide 5mCpG, 0.68% as 5mCpA, 0.59% as 5mCpT and 0.45% as 5mCpC. 5mCpG represents approximately 3.3% of all CpG dinucleotides. The experimental procedure would not have permitted the detection of 5mCp5mC, if it occurs in this system. Unusually high amounts of 6-methyladenine (approximately 4 mol %) and 7-methylguanine (approximately 2 mol %) were also detected, 6-methyladenine and 7-methylguanine occurred adjacent to all four nucleotides. The total G+C content was 33.7% as calculated from dinucleotide data and 32.9% as determined from melting profiles.