Determination of pond water quality for aquaculture and ecosystem management

Fish is the main source of animal protein for the common people of Bangladesh. About 37% of the inland fishes are obtained from the closed water fish culture where ponds play vital roles in the production system. The present study was carried out to determine the water quality (physico-chemical and biological factors) of five uncultivated or under cultivated ponds in the Chittagong University campus, Bangladesh, for aquaculture and ecosystem management. Temperature, pH, EC, BOD, COD, TSS, turbidity, NO2-, PO4 -, free CO2, CO3 -, HCO3-, Cl-, total viable bacterial count and total coliform were determined. Isolation and identification of Escherichia coli and Salmonella sp. from the water samples were performed to investigate the antibiotic sensitivity. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against ciprofloxacin was also investigated. The findings reveal that there was no significant difference in temperature (19°C to 20°C), pH (6.7 to 7.4), electrical conductivity and Cl- values in the water among the ponds and that was within the range of the requirements for the fish cultivation. Both turbidity and total dissolved solids was highest in the uncultivated botanical garden pond 2 (BGP2). BOD, COD, NO2- , PO 4-2, HCO3-, and free CO2 concentration was beyond the permissible limits for aquaculture. Total viable count and total coliform ranged from 1.3 × 10 4 to 6.6 × 10 5 cfu ml-1 and from 0.0205×10 2 to 1.10×10 2 ml-1 respectively, among the ponds where both these parameters were highest in the naturally polluted BGP2. Most of the isolated E. coli and Salmonella sp. were sensitive but few showed resistance against the antibiotics, especially in BGP1, where fishes were cultivated commercially

Antigen-Specific Memory B-cell Responses to Enterotoxigenic Escherichia coli Infection in Bangladeshi Adults

Background: Multiple infections with diverse enterotoxigenic E. coli (ETEC) strains lead to broad spectrum protection against ETEC diarrhea. However, the precise mechanism of protection against ETEC infection is still unknown. Therefore, memory B cell responses and affinity maturation of antibodies to the specific ETEC antigens might be important to understand the mechanism of protection. Methodology In this study, we investigated the heat labile toxin B subunit (LTB) and colonization factor antigens (CFA/I and CS6) specific IgA and IgG memory B cell responses in Bangladeshi adults (n = 52) who were infected with ETEC. We also investigated the avidity of IgA and IgG antibodies that developed after infection to these antigens. Principal Findings Patients infected with ETEC expressing LT or LT+heat stable toxin (ST) and CFA/I group or CS6 colonization factors developed LTB, CFA/I or CS6 specific memory B cell responses at day 30 after infection. Similarly, these patients developed high avidity IgA and IgG antibodies to LTB, CFA/I or CS6 at day 7 that remained significantly elevated at day 30 when compared to the avidity of these specific antibodies at the acute stage of infection (day 2). The memory B cell responses, antibody avidity and other immune responses to CFA/I not only developed in patients infected with ETEC expressing CFA/I but also in those infected with ETEC expressing CFA/I cross-reacting epitopes. We also detected a significant positive correlation of LTB, CFA/I and CS6 specific memory B cell responses with the corresponding increase in antibody avidity. Conclusion: This study demonstrates that natural infection with ETEC induces memory B cells and high avidity antibodies to LTB and colonization factor CFA/I and CS6 antigens that could mediate anamnestic responses on re-exposure to ETEC and may help in understanding the requirements to design an effective vaccination strategies

Circulating Mucosal Associated Invariant T Cells Are Activated in Vibrio cholerae O1 Infection and Associated with Lipopolysaccharide Antibody Responses

Background: Mucosal Associated Invariant T (MAIT) cells are innate-like T cells found in abundance in the intestinal mucosa, and are thought to play a role in bridging the innate-adaptive interface. Methods: We measured MAIT cell frequencies and antibody responses in blood from patients presenting with culture-confirmed severe cholera to a hospital in Dhaka, Bangladesh at days 2, 7, 30, and 90 of illness. Results: We found that MAIT (CD3+CD4−CD161hiVα7.2+) cells were maximally activated at day 7 after onset of cholera. In adult patients, MAIT frequencies did not change over time, whereas in child patients, MAITs were significantly decreased at day 7, and this decrease persisted to day 90. Fold changes in MAIT frequency correlated with increases in LPS IgA and IgG, but not LPS IgM nor antibody responses to cholera toxin B subunit. Conclusions: In the acute phase of cholera, MAIT cells are activated, depleted from the periphery, and as part of the innate response against V. cholerae infection, are possibly involved in mechanisms underlying class switching of antibody responses to T cell-independent antigens

Time delays between radio and X-ray and between narrow radio bands of Sgr A* flares in the shock oscillation model

We examine the time delay between radio and X-ray and between narrow radio frequency flares in Sagittarius A* (Sgr A*), from analyses of the synchrotron, bremsstrahlung and monochromatic luminosity curves. Using the results of 2D relativistic radiation magnetohydrodynamic (MHD) simulations based on the shock oscillation model, we find three types of time delay between the synchrotron and bremsstrahlung emissions: Type A with a time delay of 2 -- 3 h on the shock descending branch, Type B with no time delay and Type C with an inverse time delay of 0.5 -- 1 h on the shock ascending branch. The time delays in Types A and C are interpreted as a transit time of Alfv\'{e}n and acoustic waves between both emission dominant regions, respectively. The delay times between 22 and 43 GHz flares and between 8 and 10 GHz flares are $\sim$ 13 -- 26 min and 13 min, respectively, while the inverse delay also occurs dependently on the shock location branch. These time delays between the narrow radio bands are interpreted as the transit time of the acoustic wave between the frequency-dependent effective radii $R_{\tau_{\rm \nu=1}}$, at which the optical depth $\tau_{\rm \nu}$ at the accretion disc surface becomes $\sim$ unity. The shock oscillation model explains well the observed delay times of 0.5 -- 5 h between radio and X-ray, 20 -- 30 min between 22 and 43 GHz and $\sim$ 18 min between 8 and 10 GHz in Sgr A*.Comment: 14 pages, 14 figures, (accepted for publication in MNRAS

The social learning of threat and safety in the family:Parent-to-child transmission of social fears via verbal information

Parental verbal threat (vs. safety) information regarding the social world may impact a child's fear responses, evident in subjective, behavioral, cognitive, and physiological indices of fear. In this study, primary caregivers provided standardized verbal threat or safety information to their child (N = 68, M = 5.27 years; 34 girls) regarding two strangers in the lab. Following this manipulation, children reported fear beliefs for each stranger. Physiological and behavioral reactions were recorded as children engaged with the two strangers (who were blind to their characterization) in a social interaction task. Child attention to the strangers was measured in a visual search task. Parents also reported their own, and their child's, social anxiety symptoms. Children reported more fear for the stranger paired with threat information, but no significant differences were found in observed child fear, attention, or heart rate. Higher social anxiety symptoms on the side of the parents and the children exacerbated the effect of parental verbal threat on observed fear. Our findings reveal a causal influence of parental verbal threat information only for child‐reported fear and highlight the need to further refine the conditions under which acquired fear beliefs persist and generalize to behavior/physiology or get overruled by nonaversive real‐life encounters

The relation between early behavioural inhibition and later social anxiety, independent of attentional biases to threat

Early behavioural inhibition, a temperamental characteristic defined by fearful, overly-sensitive, avoidant, or withdrawn reactions to the unknown, is a predictor of later social anxiety. However, not all behaviourally inhibited children develop anxiety problems, and attentional bias to threat has been proposed to moderate the relation between behavioural inhibition and anxiety. The current study aimed to further specify the relation between early behavioural inhibition and later social anxiety by testing this potentially moderating role of childhood attentional bias to threat. Behavioural inhibition was assessed during toddlerhood (age 2.5 years) using laboratory observations of children’s behaviours in response to unknown objects and situations. When children were 7.5 years old, attentional bias was measured in 86 children (46 girls) using both a visual probe task and a visual search task with angry and happy faces. Child social anxiety was measured using questionnaires completed by the child and both parents, and clinical interviews conducted with both parents. Our results showed that while early behavioural inhibition was related to later social anxiety, there was no evidence for a moderation of this relation by attentional bias, suggesting that the relation between early fearful temperament and later social anxiety holds across children, independent of their attentional biases.</p

Expression of steroidogenic enzymes in placentome of ewes with pregnancy toxemia after two parturition induction methods

The regulation pattern of important enzymes in placental steroidogenesis and prostaglandins in ewes with pregnancy toxemia is reviewed. The alterations of gene expressions after the administration of aglepristone and dexamethasone are also discussed. Four healthy and 22 ewes with pregnancy toxemia were included to the study. Group AG (n=9) and Group DEX (n=9) in which ewes were injected twice with 10 mg/kg of aglepristone and once with 5 ml dexamethasone, respectively; whereas negative control [Group CG (n=4)] and pregnancy toxemia [Group PT (n=4)] groups received no treatment for parturition induction. Placentomes were collected either right after parturition or C-section. mRNA extraction from total placentome, caruncle, cotyledon and caruncle part of placentomes was carried out and Real-Time PCR was performed. Serum samples were collected and cortisol, PGFM, PGE2 and estrone sulfate concentrations were measured after treatments until parturition. The lowest mRNA expressions of steroidogenic enzymes were detected in group PT. Interestingly similar expression pattern of steroidogenic enzymes in group AG was as similar as group PT. No difference was found in expressions of 3βHSD and CYP19. PTGS2/COX2 and PGFS mRNA expressions were statistically different between groups AG-DEX and in caruncle between groups, respectively (P&lt;0.005). Significant difference could clearly be observed in EP3 expression in caruncle of DEX and AG compared to CG (P&lt;0.005); however PTGES, EP1, EP2 and EP4 expressions were not statistically different among groups (P&gt;0,05). Ostrone sulfate, PGE2 and PGFM concentrations were statistically different according to the sampling time between groups however no difference was observed in cortisol. The present study has suggests that the endocrinologic pathway controlling parturition is clearly different in ewes with pregnancy toxemia. Spontaneous parturition could occur as a consequence of immune and inflammatory processes, which could be activated by by-products of fat metabolism. Dexamethasone applications has mimicked normal parturition, however the gene expression regulations, controlling uterine contractions, are observed as similar as group PT. Probably expressions of EP1 and tissue-specific counter-expressions of cervical EP genes could refer the pathogenesis of insufficient cervical dilatation, observed in pregnancy toxemia and dexamethsone applications.

A Validated RP-HPLC Method Development for Amoxicillin in Pharmaceutical Dosage Forms

A rapid and simple Reverse Phase High Performance Liquid Chromatography (RP-HPLC) method has been developed for the quantification of Amoxicillin in tablet dosage form. Separation was achieved on Chromatopak-C18 (250mm×4.6×5micron) column in isocratic mode with mobile phase consisting of Acetonitrile: 0.2M Potassium dihydrogen phosphate buffer (pH 3) (22:78v/v) and conditions optimized with flow rate of 1 ml/minute and wavelength of detection at 283 nm. The retention time of Amoxicillin was found to be 6.4 min. Linearity was established for Amoxicillin in the range 10 100 μ g / ml with R2 value 0.999. This method was validated in accordance with ICH guidelines, the linearity, accuracy, precision, specificity, robustness, ruggedness, and system suitability results were within the acceptance criteria. Validation studies demonstrated that the proposed RP-HPLC method is simple, specific, rapid, reliable and reproducible for the determination of Amoxicillin for Quality Control level