Parimal Talukder

Fukuoka University, Fukuoka-shi, Fukuoka-ken, Japan

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Publications (5)5.3 Total impact

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    ABSTRACT: Pyriproxyfen is a juvenile hormone mimic of vital importance for insect development with little risk to humans. This study was performed to investigate whether large doses of pyriproxyfen affect the immune response in mammals. Mice were immunized thrice with ovalbumin in 5% ethanol, with or without pyriproxyfen or alum. Large doses of pyriproxyfen (9 or 15 mM) significantly enhanced specific total IgG immune response. This enhancement was no longer present 24 hr after treatment with pyriproxyfen. These results suggest that pyriproxyfen is a safe chemical. Moreover, pyriproxyfen induced higher titers of IgG2a and enhanced tumor necrosis factor-alpha and gamma-interferon responses whereas alum induced IgG1 with enhanced interleukin-4 and -10. These observations indicate that the mechanism of immune enhancement by pyriproxyfen may differ from that of alum.
    Microbiology and Immunology 04/2013; 57(4):316-22. · 1.55 Impact Factor
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    ABSTRACT: Pyriproxyfen is a juvenile hormone mimic of vital importance for insect development with little risk to humans. This study was performed to investigate whether high doses of pyriproxyfen affect the immune response in mammals. Mice were immunized thrice with OVA in 5% ethanol, with or without pyriproxyfen or alum. Pyriproxyfen significantly enhanced specific total IgG immune response. This enhancement was observed with high doses of pyriproxyfen (9 or 15 mM) and the enhancement was not observed after 24 hr in treatment with pyriproxyfen. These results therefore suggested pyriproxyfen as a safe chemical. Moreover, pyriproxyfen induced higher levels of IgG2a and enhanced TNF-α and IFN-γ responses whereas alum induced IgG1 with enhanced IL-4 and IL-10. These observations indicated that the mechanism of immune enhancement with pyriproxyfen may different from that of alum.
    Microbiology and Immunology 02/2013; · 1.55 Impact Factor
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    ABSTRACT: Infectious diseases, especially, diarrhoea, are responsible for high mortality rates in developing countries. Zinc supplementation shows beneficial effects against such diseases, but the mechanism of action is poorly understood. Here, we examined whether zinc supplementation can improve mucosal innate immunity through induction of antimicrobial peptide secretion from intestinal epithelial cells. Zinc was found to induce secretion of the antimicrobial peptide LL-37 from Caco-2 cell in a dose (0.63±0.09ng/mL and 0.54±0.06ng/mL at 20μM and 50μM respectively) and time dependent manner. LL-37 secretion increased immediately (1h) after exposure to 20μM Zn (0.29±0.04ng/mL), which continued up to 48h of exposure (0.58±0.05ng/mL). Zinc induces the phosphorylation of ERK and p38 MAP kinase and regulates LL-37 secretion through these MAP kinases. Zinc supplementation may have beneficial effects on mucosal innate immunity via secretion of LL-37.
    International immunopharmacology 10/2010; 11(1):141-4. · 2.21 Impact Factor
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    ABSTRACT: There have been a number of recent studies regarding the use of engineered insect symbiont bacteria for control of insect-borne diseases. However, searches for cultivable bacteria residing in the mosquito midgut have met with little success. The present study was conducted to evaluate the effects of the human non-pathogenic lactobacilli on midgut protein synthesis in the dengue vector Aedes albopictus, taking into account the ease of infection and its persistence. It was showed that antibiotic treatment of mosquitoes did not prevent experimental infection, and readily reduced undesired infection, but did not prevent re-infection by Lactobacillus spp. It suggests a high potential of colonization of a target vector population under field conditions. Ingested lactobacilli remained in the female midgut for five days. Lactobacillus reuteri (Lactobacillales: Lactobacillaceae) showed more specific proteins than Lactobacillus brevis (Lactobacillales: Lactobacillaceae). Some proteins identified in L. brevis were present at much higher levels in L. reuteri, while other proteins found in the latter were found at higher levels in the former. Infection by L. brevis resulted in the absence of many proteins. In contrast, L. reuteri infection resulted in increased levels of synthesis of a set of proteins present in the healthy midguts. Both bacteria triggered changes in midgut protein synthesis, but activation was seen to a greater extent with L. reuteri. These results are discussed in the context of paratransgenesis. Key words: Bacteria, Lactobacillus reuteri, Lactobacillus brevis, Aedes albopictus, midgut, ease of infection, persistence, protein synthesis.
    Journal of Parasitology and Vector Biology. 01/2010; 2(2):14-21.
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    ABSTRACT: There is a great deal of current research interest in utilising bacteria for the control of intractable arthropod-borne diseases such as dengue. Although there is accumulating evidence that bacterial infection is a promising control strategy, most studies on bacteria-insect interactions lacked useful markers for detecting pathogenesis. This provided the impetus to investigate bacterial infection in the dengue vector Aedes albopictus. The infection persistence patterns in key organs of the alimentary canal of females were examined using a GFP-expressing strain of Escherichia coli (Migula). Just after feeding with sugar meal containing the bacteria, the crop and midgut as well as parts of the Malpighian tubules showed fluorescence. From 1 h onwards, bacterial populations declined sharply in both the midgut and crop, with complete elimination in the former but persistence of bacteria at 7 h post-feeding in the latter. After 24 h, neither organ retained the fluorescent marker. However, culture of homogenates of these organs in Luria-Bertani medium revealed the presence of a bacterial population in the crop, but not in the midgut. These observations suggest a difference in the potential physiological actions expressible by the two organs. In fact, both are storage sites for ingested fluids, but the midgut has greater physiological activity. Presumably, one of these activities contributed to eliminating GFP- expressing E. coli from the A. albopictus midgut after 24 h. The results of the present study using a fluorescent marker to detect infection may be useful for developing strategies to fully characterise the main steps involved in the bacterial infection process in insects.
    01/2009;