Post-embryonic developmental rates as a function of food type in the cyclopoid copepod, Mesocyclops thermocyclopoides Harada

We studied under laboratory conditions the post-embryonic developmentalrates (from nauplii to adult stage) of Mesocyclops thermocyclopoides,commonly found in the eutrophic and hypertrophic local ponds,in relation to different food types. Nauplii hatched from theeggs collected from laboratory-maintained mass cultures werereared at 25l.5C, using the following test diets: bacteria(Klebsiella aerogenes), cyanobacteria (Microcystis aeruginosa,as single cells and in the form of colonies), green algae (Chlorella,Scenedesmus and Chlorogonium), ciliates (Tetrahymena) and rotifers(Brachionus angularis). The developmental rates were fastest,and the proportion of nauplii reaching the copepodid stage andthat of copepodids reaching the adult stage the highest, withChlorogonium, followed by ciliates and rotifers. Developmentwas incomplete with bacteria and Microcys-tis.Ttie algae Chlorellaand Scenedesmus supported complete post-embryonic developmentonly when cultured in media enriched with beef extract, bactotryptoneand yeast extract. With rotifers as the exclusive food, >70%of the nauplii reached the copepodid stage, and >85% of thecopepodids the adult stage. The ratio (D_c/D_n) of copepodid duration(D_c) and naupliar duration (D_n) was significantly differentfrom 1.0, indicating the absence of isochronal development inM.thermocyclopoides. Our results show that post-embryonic developmentin this species is not possible with certain algal diets, probablybecause of nutritional deficiencies, and that the later stagenauplii are capable of capturing rotifers and utilizing themas food to complete their development to the adult stage.     

Extrapolation of Inter Domain Communications and Substrate Binding Cavity of Camel HSP70 1A: A Molecular Modeling and Dynamics Simulation Study

Heat shock protein 70 (HSP70) is an important chaperone, involved in protein folding, refolding, translocation and complex remodeling reactions under normal as well as stress conditions. However, expression of HSPA1A gene in heat and cold stress conditions associates with other chaperons and perform its function. Experimental structure for Camel HSP70 protein (cHSP70) has not been reported so far. Hence, we constructed 3D models of cHSP70 through multi- template comparative modeling with HSP110 protein of S. cerevisiae (open state) and with HSP70 protein of E. coli 70kDa DnaK (close state) and relaxed them for 100 nanoseconds (ns) using all-atom Molecular Dynamics (MD) Simulation. Two stable conformations of cHSP70 with Substrate Binding Domain (SBD) in open and close states were obtained. The collective mode analysis of different transitions of open state to close state and vice versa was examined via Principal Component Analysis (PCA) and Minimum Distance Matrix (MDM). The results provide mechanistic representation of the communication between Nucleotide Binding Domain (NBD) and SBD to identify the role of sub domains in conformational change mechanism, which leads the chaperone cycle of cHSP70. Further, residues present in the chaperon functioning site were also identified through protein-peptide docking. This study provides an overall insight into the inter domain communication mechanism and identification of the chaperon binding cavity, which explains the underlying mechanism involved during heat and cold stress conditions in camel.     

Luminescent whole-cell cyanobacterial bioreporter for measuring Fe availability in diverse marine environments

A Synechococcus sp. strain PCC 7002 Fe bioreporter was constructed containing the isiAB promoter fused to the Vibrio harveyi luxAB genes. Bioreporter luminescence was characterized with respect to the free ferric ion concentration in trace metal-buffered synthetic medium. The applicability of the Fe bioreporter to assess Fe availability in the natural environment was tested by using samples collected from the Baltic Sea and from the high-nutrient, low-chlorophyll subarctic Pacific Ocean. Parallel assessment of dissolved Fe and bioreporter response confirmed that direct chemical measurements of dissolved Fe should not be considered alone when assessing Fe availability to phytoplankton.     

Differential regulation of cholera toxin-inhibited Na-H exchange isoforms by butyrate in rat ileum

Electroneutral Na absorption occurs in the intestine via sodium-hydrogen exchanger (NHE) isoforms NHE2 and NHE3. Bicarbonate and butyrate both stimulate electroneutral Na absorption through NHE. Bicarbonate- but not butyrate-dependent Na absorption is inhibited by cholera toxin (CT). Long-term exposure to butyrate also influences expression of apical membrane proteins in epithelial cells. These studies investigated the effects of short- and long-term in vivo exposure to butyrate on apical membrane NHE and mRNA, protein expression, and activity in rat ileal epithelium that had been exposed to CT. Ileal loops were exposed to CT in vivo for 5 h and apical membrane vesicles were isolated. 22Na uptake was measured by using the inhibitor HOE694 to identify NHE2 and NHE3 activity, and Western blot analyses were performed. CT reduced total NHE activity by 70% in apical membrane vesicles with inhibition of both NHE2 and NHE3. Reduced NHE3 activity and protein expression remained low following removal of CT but increased to control values following incubation of the ileal loop with butyrate for 2 h. In parallel there was a 40% decrease in CT-induced increase in cAMP content. In contrast, NHE2 activity partially increased following removal of CT and was further increased to control levels by butyrate. NHE2 protein expression did not parallel its activity. Neither NHE2 nor NHE3 mRNA content were affected by CT or butyrate. These results indicate that CT has varying effects on the two apical NHE isoforms, inhibiting NHE2 activity without altering its protein expression and reducing both NHE3 activity and protein expression. Butyrate restores both CT-inhibited NHE2 and NHE3 activities to normal levels but via different mechanisms.     

Electropolymerization molecularly imprinted polymer (E-MIP) SPR sensing of drug molecules: pre-polymerization complexed terthiophene and carbazole electroactive monomers

A novel chemosensitive ultrathin film with high selectivity was developed for the detection of naproxen, paracetamol, and theophylline using non-covalent electropolymerized molecular imprinted polymers (E-MIP). A series of monofunctional and bifunctional H-bonding terthiophene and carbazole monomers were compared for imprinting these drugs without the use of a separate cross-linker. A key step is the fast and efficient potentiostatic method of washing the template, which facilitated enhanced real-time sensing by surface plasmon resonance (SPR) spectroscopy. Various surface characterizations (contact angle, ellipsometry, XPS, AFM) of the E-MIP film verified the templating and release of the drug from the cross-linked conducting polymer film.     

AUTOBA: Automation of backbone assignment from HN(C)N suite of experiments

Development of efficient strategies and automation represent important milestones of progress in rapid structure determination efforts in proteomics research. In this context, we present here an efficient algorithm named as AUTOBA (Automatic Backbone Assignment) designed to automate the assignment protocol based on HN(C)N suite of experiments. Depending upon the spectral dispersion, the user can record 2D or 3D versions of the experiments for assignment. The algorithm uses as inputs: (i) protein primary sequence and (ii) peak-lists from user defined HN(C)N suite of experiments. In the end, one gets H^N, ¹⁵N, C^α and C′ assignments (in common BMRB format) for the individual residues along the polypeptide chain. The success of the algorithm has been demonstrated, not only with experimental spectra recorded on two small globular proteins: ubiquitin (76 aa) and M-crystallin (85 aa), but also with simulated spectra of 27 other proteins using assignment data from the BMRB.