31005724
Acaricidal properties of Ricinus communis leaf extracts against organophosphate and pyrethroids resistant Rhipicephalus (Boophilus) microplus.
Indian cattle ticks have developed resistance to commonly used acaricides and an attempt has been made to formulate an ecofriendly herbal preparation for the control of acaricide resistant ticks. A 95% ethanolic extract of Ricinus communis was used to test the efficacy against reference acaricide resistant lines by in vitro assay. In in vitro assay, the extract significantly affects the mortality rate of ticks in dose-dependent manner ranging from 35.0 ± 5.0 to 95.0 ± 5.0% with an additional effect on reproductive physiology of ticks by inhibiting 36.4-63.1% of oviposition. The leaf extract was found effective in killing 48.0, 56.7 and 60.0% diazinon, deltamethrin and multi-acaricide resistant ticks, respectively. However, the cidal and oviposition limiting properties of the extract were separated when the extract was fractionated with hexane, chloroform, n-butanol and water. The HPTLC finger printing profile of R. communis leaf extract under λ(max.) - 254 showed presence of quercetin, gallic acid, flavone and kaempferol which seemed to have synergistic acaricidal action. In vivo experiment resulted in 59.9% efficacy on Ist challenge, however, following 2nd challenge the efficacy was reduced to 48.5%. The results indicated that the 95% ethanolic leaf extract of R. communis can be used effectively in integrated format for the control of acaricide resistant ticks.
25372281
Progress in development of vaccine against Hyalomma anatolicum anatolicum-Indian scenario.
Hyalomma anatolicum anatolicum, a three host tick vector transmitting the causative agent of bovine tropical theileriosis, is widely distributed throughout India. As a component of integrated control measures against the tick vector, attempts have been made to identify candidate protein molecules for development of an anti-tick vaccine in the different stages of this tick species. By strategic methods of isolation of the targeted molecules using affinity purification of proteins showing reactivity with immunoglobulins of animals previously immunized with different sources of tick antigen, six proteins were isolated in a significantly pure form. The recovery percentage of the candidate proteins was very low in the range of 1.8-8.0%. The protective potentiality of the antigens was tested in immunization and challenge trials and maximum potential was observed in the proteins isolated from total larval extracts, nymphal extracts and in larval glycoprotein. One of the antigens with a molecular weight of 37kDa isolated from larvae of H. a. anatolicum was found to have some adverse effect on development of Theileria annulata in the vector tick. The progress in the development of immunoprophylactic measures against H. a. anatolicum is discussed.
19083493
Assessment of duration of immunity in crossbred cattle immunized with glycoproteins isolated from Hyalomma anatolicum anatolicum and Boophilus microplus
To develop immunoprophylactic measures against multi-tick infestation, two glycoproteins of 34 and 29 kDa were isolated from the larvae of Hyalomma anatolicum anatolicum and Boophilus microplus, respectively, and assessed for their efficacy against experimental challenge infestations. The synergistic effect of the antigens in the presence of incomplete Freund’s adjuvant was found to confer protection (DT%) in animals against 56.48% of larvae and 52% of adults of H. a. anatolicum, while the effect was 40% against adults of B. microplus. The efficacy (E%) of the antigens in combination against larvae and adults of H. a. anatolicum was calculated as 70% and 64.3%, respectively, and 63% against adults of B. microplus. A direct correlation between anti-glycoprotein antibody response and protection against infestation was observed. Western blot analysis detected specific antigen in the sera of animals of group A. The antigens in combination with incomplete Freund’s adjuvant could protect animals from H. a. anatolicum and B. microplus infestations for at least 30 weeks. The possibility of employing the vaccination strategy in Indian conditions is discussed.
36630069
Upcoming and future strategies of tick control: a review.
Ticks are distributed worldwide and significantly impact human and animal health. Due to severe problems associated with the continuous use of acaricides on animals, integrated tick management is recommended. Increasing public health concern over the tick-borne diseases demands the strategic control of ticks on animals that transmit diseases to human beings. Immunological control of tick vector of Kyasanur Forest Disease (KFD) on cattle and other wild reservoir hosts is one of the possible alternative strategy for reducing the transmission of KFD to man. Chemical-vaccine synergies have been demonstrated and a combination of chemical and vaccine for tick and tick-borne disease control has been identified as a sustainable option. Studies have suggested the possibility of vaccine strategies directed towards both tick control and transmission of pathogens. Besides tick vaccine, use of endosymbionts, which are essential for the survival of arthropod hosts, for the control of tick vectors will be one of the targeted areas of research in near future. India with huge natural resources of herbs and other medicinal plants, the possibilities of developing herbal acaricides is discussed. The future of research directed towards target identification is exciting because of new and emerging technologies for gene discovery and vaccine formulation.
19314963
Comparative immunopotentiating properties of saponin and incomplete Freund's adjuvant coupled to affinity purified larval antigen of Hyalomma anatolicum anatolicum.
Comparative immunostimulatory properties of saponin and incomplete Freund's adjuvant (IFA) were studied using affinity purified 39 kDa larval antigen of Hyalomma anatolicum anatolicum. Significant antibody response to 39 kDa antigen was detected in the sera of rabbits immunized with both 39 kDa plus saponin and 39 kDa plus IFA in comparison to their corresponding control animals. Insignificant differences were noted in the antibody response between the animals of two immunized groups. Upon challenge, the animals immunized with 39 kDa plus IFA rejected 76.2 +/- 9.7% of larvae and 45.8 +/- 4.1% of adults while in group of animals injected with 39 kDa plus saponin rejected 80.9 +/- 11.2% of larvae and 47.2 +/- 5.7% of adults.
21394365
Chlorinated phenols control the expression of the multidrug resistance efflux pump MexAB-OprM in Pseudomonas aeruginosa by interacting with NalC.
NalC is a TetR type regulator that represses the multidrug efflux pump MexAB-OprM in Pseudomonas aeruginosa. Here we explain the mechanism of NalC-mediated regulation of MexAB-OprM. We show that NalC non-covalently binds chlorinated phenols and chemicals containing chlorophenol side-chains such as triclosan. NalC-chlorinated phenol binding results in its dissociation from promoter DNA and upregulation of NalC's downstream targets, including the MexR antirepressor ArmR. ArmR upregulation and MexR-ArmR complex formation have previously been shown to upregulate MexAB-OprM. In vivo mexB and armR expression analyses were used to corroborate in vitro NalC-chlorinated phenol binding. We also show that the interaction between chlorinated phenols and NalC is reversible, such that removal of these chemicals restored NalC promoter DNA binding. Thus, the NalC-chlorinated phenol interaction is likely a pertinent physiological mechanism that P. aeruginosa uses to control expression of the MexAB-OprM efflux pump.
36570389
Elimination of Mercury and Organomercurials by Nitrogen-Fixing Bacteria
Bacteria isolated from mercury-polluted environments are often resistant to mercuric ions (Hg{sup 2+}) and organomercurials. Plasmids determining mercury resistance have been well characterized in gram-negative system. However, in Staphylococcus aureus mercury resistance has been found to be chromosomally determined. The known mechanism of bacterial Hg{sup 2+}-resistance is detoxification of the toxic Hg{sup 2+} by its enzymatic transformation by mercuric reductase to Hg (o). Organomercurial lyase mediates the degradation of organomercurial compounds to Hg{sup 2+}. Mercury and organomercurial resistances have been studied in different bacterial genera. There is little information on Hg-resistance in N{sub 2}-fixing soil bacteria, however, in many developing countries, including India, mercury pollution is still a problem because Hg-based pesticides and fungicides are still used routinely as seed-dressers in agriculture to control soil-borne and seed-borne fungal diseases. Volatilization of Hg from laboratory media by mercury-resistant bacteria containing low levels of mercury has been reported by several workers. It is interesting to note that N{sub 2}-fixing, Hg-resistant soil isolates could volatilize Hg from medium containing very high amounts of HgCl{sub 2}. In the present paper we report the volatilization patterns of five N{sub 2}-fixing bacterial strains, the effect of different inducers on mercuric reductase, and the pattern of substratemore » utilization by organomercurial lyase. In the presence of a low concentration of HgCl{sub 2}. enzymatic detoxification is sufficient to combat the adverse situation created by the presence of Hg{sup 2+} ions. In the presence of a high concentration of HgCl{sub 2}, intracellular sequestration by Hg{sup 2+} binding components may play an additional role in counteracting Hg-toxicity.« less
10233741
Histone-like protein HU from Deinococcus radiodurans binds preferentially to four-way DNA junctions.
The histone-like protein HU from Escherichia coli is involved in DNA compaction and in processes such as DNA repair and recombination. Its participation in these events is reflected in its ability to bend DNA and in its preferred binding to DNA junctions and DNA with single-strand breaks. Deinococcus radiodurans is unique in its ability to reconstitute its genome from double strand breaks incurred after exposure to ionizing radiation. Using electrophoretic mobility shift assays (EMSA), we show that D.radiodurans HU (DrHU) binds preferentially only to DNA junctions, with half-maximal saturation of 18 nM. In distinct contrast to E.coli HU, DrHU does not exhibit a marked preference for DNA with nicks or gaps compared to perfect duplex DNA, nor is it able to mediate circularization of linear duplex DNA. These unexpected properties identify DrHU as the first member of the HU protein family not to serve an architectural role and point to its potential participation in DNA recombination events. Our data also point to a mechanism whereby differential target site selection by HU proteins is achieved and suggest that the substrate specificity of HU proteins should be expected to vary as a consequence of their individual capacity for inducing the required DNA bend.
11257195
A quantile-based method for association mapping of quantitative phenotypes: an application to rheumatoid arthritis phenotypes
Genetic association of population-based quantitative trait data has traditionally been analyzed using analysis of variance (ANOVA). However, violations of certain statistical assumptions may lead to false-positive association results. In this study, we have explored model-free alternatives to ANOVA using correlations between allele frequencies in the different quantile intervals of the quantitative trait and the quantile values. We performed genome-wide association scans on anti-cyclic citrullinated peptide and rheumatoid factor-immunoglobulin M, two quantitative traits correlated with rheumatoid arthritis, using the data provided in Genetic Analysis Workshop 16. Both the quantitative traits exhibited significant evidence of association on Chromosome 6, although not in the human leukocyte antigen region which is known to harbor a major gene predisposing to rheumatoid arthritis. We found that while a majority of the significant findings using the asymptotic thresholds of ANOVA was not validated using permutations, a relatively higher proportion of the significant findings using the asymptotic cut-offs of the correlation statistic were validated using permutations.
24936933
Mechanism of intestinal entry of infectious prion protein in the pathogenesis of variant Creutzfeldt-Jakob disease.
The pathogenesis of variant Creutzfeldt-Jakob disease (vCJD) is most likely to be dependent on intestinal entry of orally ingested infectious prion proteins, though tonsils or other oral portals of entry are possible. The exact route of entry of infectious prion proteins is uncertain but receptors for prion proteins such as laminin receptor precursor (LRP) may be expressed on intestinal brush border. Cellular prion protein (PrP(c)) is expressed on intestinal enteric nervous system and is separated by a single layer of epithelial cells from ingested infectious prion proteins. Intestinal M cells in the Peyer's patches may also transcytose prion proteins which may be transported to the lymphatic system by migrating dendritic cells underlying the M cells. The relative importance of the several potential portals of intestinal entry of infectious prion proteins is uncertain but may determine susceptibility of the population and also potential preventive strategies.