The effect of single giant interneuron lesions on wind-evoked motor responses in the cockroach,Periplaneta americana

In order to determine the contribution of individual giant interneurons (GIs) to wind-evoked motor outputs, responses were recorded from depressor and levator motor neurons in the cockroach Periplaneta americana to wind puffs of different directions. The depressor response was generally stronger to wind from the ipsilateral rear than to wind from the contralateral rear. The levator response was more variable but was more often stronger to wind from the contralateral rear than to wind from the ipsilateral rear. These results are as expected based on behavioral responses to wind puffs. (Camhi and Tom, 1978). The depressor response was nearly or totally abolished by severing the ipsilateral connective of the nerve cord but was little affected by severing the contralateral connective. The levator reponse was greatly reduced for some angles by severing the ipsilateral connective and for other angles by severing the contralateral connective. Blocking conduction in the ipsilateral GI 5 nearly or completely abolished the depressor response to wind from the ipsilateral rear. This is the first time that a GI has been shown to be necessary, not just sufficient, for a given motor output.     

Synthesis and evaluation of in vitro antioxidant capacities of some benzimidazole derivatives

New, except 1d, melatonin analogue benzimidazole derivatives were synthesized and characterized in the present study. The potential role of melatonin as an antioxidant by scavenging and detoxifying ROS raised the possibility that compounds that are analogous to melatonin can also be used for their antioxidant properties. Therefore the antioxidant effects of the newly synthesized compounds were investigated in vitro by means of their inhibitory effect on hydrogen peroxide-induced erythrocyte membrane lipid peroxidation (EMLP) and on various erythrocyte antioxidant enzymes viz. superoxide dismutase (SOD), catalase (CAT) and glucose-6-phosphate dehydrogenase (G6PD). The synthesized benzimidazole derivatives showed remarkable antioxidant activity in vitro in the H₂O₂-induced EMLP system. Furthermore their effects on various antioxidant enzymes are discussed and evaluated from the perspective of structure- activity relationships.     

25-hydroxyvitamin D3 1alpha-hydroxylase and vitamin D receptor expression in papillary thyroid carcinoma.

Vitamin D receptor (VDR) and 25-hydroxyvitamin D3 1-alpha-hydroxylase expression have recently been shown to be upregulated in several tumors and thought to represent an important endogenous response to tumor progression. Little is known about the expression of these proteins in thyroid carcinoma, although previous reports have documented evidence of the biological effect of vitamin D in thyroid cells. Using paraffin-embedded and frozen sections of papillary thyroid carcinoma, we utilized real-time quantitative RT-PCR and immunohistochemistry to characterize the expression of VDR and 1-alpha-hydroxylase in thyroid follicular cells, with special emphasis on papillary thyroid carcinoma (PTC). VDR and 1-alpha-hydroxylase expression were increased in PTC compared with normal thyroid tissue and especially high in areas of lymphocyte infiltration. Expression of VDR and 1-alpha-hydroxylase in PTC may be compatible with an overall favorable prognosis for this tumor type and may constitute important prerequisites for using vitamin D and/or vitamin D analogs in the treatment of PTC.     

Local host ant specificity of Phengaris (Maculinea) teleius butterfly,an obligatory social parasite of Myrmica ants

1. Phengaris butterflies are obligatory social parasites of Myrmica ants. Early research suggested that there is a different Myrmica host species for each of the five European Phengaris social parasites, but more recent studies have shown that this was an oversimplification. 2. The pattern of host ant specificity within a Phengaris teleius metapopulation from southern Poland is reported. A combination of studying the frequency distribution of Phengaris occurrence and morphometrics on adult butterflies were used to test whether use of different host species is reflected in larval development. 3. Phengaris teleius larvae were found to survive in colonies of four Myrmica species: M. scabrinodis, M. rubra, M. ruginodis, and M. rugulosa. Myrmica scabrinodis was the most abundant species under the host plant but the percentage of infested nests was similar to other host ant species at two sites and lower in comparison to nests of M. rubra and M. ruginodis at the other two sites. Morphometric measurements of adult butterflies reared by wild colonies of M. scabrinodis and M. ruginodis showed that wing size and number of wing spots were slightly greater for adults eclosing from nests of M. ruginodis. 4. Our results suggest that P. teleius in the populations studied is less specialised than previously suggested. The results are consistent with the hypothesis that P. teleius is expected to be the least specific of the European Phengaris species, as it has the largest and best defended fourth‐instar caterpillars and, as a predatory species, it spends less time in the central larval chambers of the host colonies. The fact that individuals reared by M. ruginodis had wider hind wings may suggest that P. teleius had better access to resources in M. ruginodis than in M. scabrinodis colonies.     

Peroxisomes contain a specific phytanoyl-CoA/pristanoyl-CoA thioesterase acting as a novel auxiliary enzyme in alpha- and beta-oxidation of methyl-branched fatty acids in mouse

Phytanic acid and pristanic acid are derived from phytol, which enter the body via the diet. Phytanic acid contains a methyl group in position three and, therefore, cannot undergo beta-oxidation directly but instead must first undergo alpha-oxidation to pristanic acid, which then enters beta-oxidation. Both these pathways occur in peroxisomes, and in this study we have identified a novel peroxisomal acyl-CoA thioesterase named ACOT6, which we show is specifically involved in phytanic acid and pristanic acid metabolism. Sequence analysis of ACOT6 revealed a putative peroxisomal targeting signal at the C-terminal end, and cellular localization experiments verified it as a peroxisomal enzyme. Subcellular fractionation experiments showed that peroxisomes contain by far the highest phytanoyl-CoA/pristanoyl-CoA thioesterase activity in the cell, which could be almost completely immunoprecipitated using an ACOT6 antibody. Acot6 mRNA was mainly expressed in white adipose tissue and was co-expressed in tissues with Acox3 (the pristanoyl-CoA oxidase). Furthermore, Acot6 was identified as a target gene of the peroxisome proliferator-activated receptor alpha (PPARalpha) and is up-regulated in mouse liver in a PPARalpha-dependent manner.     

Disease-associated glycosylated molecular variants of human C-reactive protein activate complement-mediated hemolysis of erythrocytes in tuberculosis and Indian visceral leishmaniasis

Human C-reactive protein (CRP), as a mediator of innate immunity, removed damaged cells by activating the classical complement pathway. Previous studies have successfully demonstrated that CRPs are differentially induced as glycosylated molecular variants in certain pathological conditions. Affinity-purified CRPs from two most prevalent diseases in India viz. tuberculosis (TB) and visceral leishmaniasis (VL) have differential glycosylation in their sugar composition and linkages. As anemia is a common manifestation in TB and VL, we assessed the contributory role of glycosylated CRPs to influence hemolysis via CRP-complement-pathway as compared to healthy control subjects. Accordingly, the specific binding of glycosylated CRPs with erythrocytes was established by flow-cytometry and ELISA. Significantly, deglycosylated CRPs showed a 7–8-fold reduced binding with erythrocytes confirming the role of glycosylated moieties. Scatchard analysis revealed striking differences in the apparent binding constants (10⁴–10⁵ M⁻¹) and number of binding sites (10⁶–10⁷sites/erythrocyte) for CRP on patients’ erythrocytes as compared to normal. Western blotting along with immunoprecipitation analysis revealed the presence of distinct molecular determinants on TB and VL erythrocytes specific to disease-associated CRP. Increased fragility, hydrophobicity and decreased rigidity of diseased-erythrocytes upon binding with glycosylated CRP suggested membrane damage. Finally, the erythrocyte-CRP binding was shown to activate the CRP-complement-cascade causing hemolysis, even at physiological concentration of CRP (10 μg/ml). Thus, it may be postulated that CRP have a protective role towards the clearance of damaged-erythrocytes in these two diseases.