Understanding Atomic (Hyrdogenic) Hybrid Orbitals Part 2, sp^2

An earlier discussion of sp hybrid orbitals is extended to include orbitals made up to an s orbital and two p orbitals.

Bioactive Metabolites Produced by Penicillium sp.1 and sp.2, Two Endophytes Associated with Alibertia macrophylla (Rubiaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular mechanisms of Ca$\sp{2+}$ signal transduction from cardiac troponin C to troponin I

$\rm Ca\sp{2+}$-dependent exposure of an N-terminal hydrophobic region in troponin C (TnC) is thought to be important for the regulation of contraction in striated muscle. To study these conformational changes in cardiac troponin (cTnC), the $\varepsilon$C and $\varepsilon$H chemical shifts for all 10 Met residues in cTnC were sequence-specific assigned on NMR spectra using a combination of two dimensional NMR techniques and site-directed mutagenesis. The assigned methyl-Met chemical shifts were used as structural markers to monitor conformational changes induced by $\rm Ca\sp{2+}.$ The results showed that binding of $\rm Ca\sp{2+}$ to the regulatory site in the N-domain induced large changes in the $\varepsilon$H and $\varepsilon$C chemical shifts of Met 45, Met 80, Met 81 in the predicted N-terminal hydrophobic region, but had no effect on the chemical shifts of Met residues located in the C-domain. These results suggest that the $\rm Ca\sp{2+}$-dependent functions of cTnC are mainly through N-terminal domain of cTnC.^ To further define the molecular mechanism by which TnC regulates muscle contraction, single Cys residues were engineered at positions 45, 81, 84 or 85 in the N-terminal hydrophobic region of cTnC to provide sites for attachment of specific blocking groups. Blocking groups were coupled to these Cys residues in cTnC mutants and the covalent adducts were tested for activity in TnC-extracted myofibrils. Covalent modification of cTnC(C45) had no effect on maximal myofibril ATPase activity. Greatly decreased myofibril ATPase activity resulted when the peptide or biotin was conjugated to residue 81 in cTnC(C81), while less inhibition resulted from covalent modification of cTnC(C84) or cTnC(C85). The results suggest that limited sites of the N-terminal hydrophobic region in cTnC are important for transducing the $\rm Ca\sp{2+}$ signal to troponin I (TnI) and are sensitive to modification, while other regions are less important or can adapt to steric hindrances introduced by bulky blocking groups.^ Although the exposed TnI interaction site in the N-terminal hydrophobic region of TnC is crucial for function of TnC, other regions in the N-domain of TnC may also participate in transducing the $\rm Ca\sp{2+}$ signal and conferring the maximal activation of actomyosin ATPase. The interactions between the B-/C-helices of cTnC and cTnI were characterized using a combination of site-directed mutagenesis, fluorescence and covalent modification. The results suggest that the $\rm Ca\sp{2+}$-dependent interactions of the B-/C-helices of cTnC with TnI may be required for the maximal activation of muscle contraction. ^

Antibody levels against GLURP R2, MSP1 block 2 hybrid and AS202.11 and the risk of malaria in children living in hyperendemic (Burkina Faso) and hypo-endemic (Ghana) areas.

Differences in parasite transmission intensity influence the process of acquisition of host immunity to Plasmodium falciparum malaria and ultimately, the rate of malaria related morbidity and mortality. Potential vaccines being designed to complement current intervention efforts therefore need to be evaluated against different malaria endemicity backgrounds. The associations between antibody responses to the chimeric merozoite surface protein 1 block 2 hybrid (MSP1 hybrid), glutamate-rich protein region 2 (GLURP R2) and the peptide AS202.11, and the risk of malaria were assessed in children living in malaria hyperendemic (Burkina Faso, n = 354) and hypo-endemic (Ghana, n = 209) areas. Using the same reagent lots and standardized protocols for both study sites, immunoglobulin (Ig) M, IgG and IgG sub-class levels to each antigen were measured by ELISA in plasma from the children (aged 6-72 months). Associations between antibody levels and risk of malaria were assessed using Cox regression models adjusting for covariates. There was a significant association between GLURP R2 IgG3 and reduced risk of malaria after adjusting age of children in both the Burkinabe (hazard ratio 0.82; 95 % CI 0.74-0.91, p < 0.0001) and the Ghanaian (HR 0.48; 95 % CI 0.25-0.91, p = 0.02) cohorts. MSP1 hybrid IgM was associated (HR 0.85; 95 % CI 0.73-0.98, p = 0.02) with reduced risk of malaria in Burkina Faso cohort while IgG against AS202.11 in the Ghanaian children was associated with increased risk of malaria (HR 1.29; 95 % CI 1.01-1.65, p = 0.04). These findings support further development of GLURP R2 and MSP1 block 2 hybrid, perhaps as a fusion vaccine antigen targeting malaria blood stage that can be deployed in areas of varying transmission intensity.

Segregation of species-specific male attractiveness in f(2) hybrid lake Malawi cichlid fish

Among the huge radiations of haplochromine cichlid fish in Lakes Malawi and Victoria, closely related species are often reproductively isolated via female mate choice although viable fertile hybrids can be produced when females are confined only with heterospecific males. We generated F(2) hybrid males from a cross between a pair of closely related sympatric cichlid fish from Lake Malawi. Laboratory mate choice experiments using microsatellite paternity analysis demonstrated that F(2) hybrid males differed significantly in their attractiveness to females of the two parental species, indicating heritable variation in traits involved in mate choice that may contribute to reproductive isolation between these species. We found no significant correlation between male mating success and any measurement of male colour pattern. A simple quantitative genetic model of reproductive isolation suggests that there may be as few as two chromosomal regions controlling species-specific attractiveness. We propose that adaptive radiation of Lake Malawi cichlids could be facilitated by the presence of genes with major effects on mate choice and reproductive isolation.

Selective functionalisation of Re6 cluster anionic units:from hexa-hydroxo [Re6Q8(OH)6]4− (Q = S, Se) to neutral trans-[Re6Q8L4L′2] hybrid building blocks

The reaction of [Re6Q8(OH)6]4- (Q = S, Se) with p-tertbutylpyridine (TBP) in water leads to neutral trans-[Re6Q8(TBP)4(OH)2] whose hydroxyl reactivity with carboxylic acid and TBP exchange reaction with functional pyridine have been investigated.

Physicochemical and molecular characterization of bacteriophages ΦSP-1 and ΦSP-3, specific for pathogenic Salmonella and evaluation of their potential as biocontrol agent

This thesis entitled Physicochemical and molecular characterization of bacteriophages ΦSP-1and ΦSP-3, specific for pathogenic Salmonella and evaluation of their potential as biocontrol agent . Salmonella were screened using standard methodologies from various environmental samples including chicken caecum. Salmonella strains, which were previously isolated and stocked in the lab, were also included in this study as host, for screening Salmonella specific lytic phages. The Salmonella strain in this study designated as S49 which helped in phage propagation by acting as host bacteria was identified as Salmonella enterica subsp. enterica by 16S rRNA gene analysis and serotyping . A total of three Salmonella specific phage named as ΦSP-1, ΦSP-2 and ΦSP-3 were isolated from chicken intestine samples via an enrichment protocol employing the double agar overlay method. ΦSP-1 and ΦSP-3 showing consistent lytic nature were selected for further study and were purified by repeated plating after picking of single isolated plaques from the lawns of Salmonella S49 plates. Both the phages produced small, clear plaques indicating their lytic nature. ΦSP-1 and ΦSP-3 were concentrated employing PEG-NaCl precipitation method before further characterization. The focus of present study was to isolate, characterize and verify the efficacy of lytic bacteriophages against the robust pathogen Salmonella, capable of surviving under various hostile conditions. Two phages, ΦSP-1 and ΦSP-3, belonging to two families, Podovoridae and Siphoviridae were isolated.

Obtenção e uso das plantas medicinais no distrito de Martim Francisco, Município de Mogi-Mirim, SP, Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Understanding Atomic (Hydrogenic) Hybrid Orbitals

Hybrid (sp) orbitals are illustrated in various plotting schemes to aid in understaning their structure.

Structure of saccharose-based carbon and transport of confined fluids: hybrid reverse Monte Carlo reconstruction and simulation studies

We present results of the reconstruction of a saccharose-based activated carbon (CS1000a) using hybrid reverse Monte Carlo (HRMC) simulation, recently proposed by Opletal et al. [1]. Interaction between carbon atoms in the simulation is modeled by an environment dependent interaction potential (EDIP) [2,3]. The reconstructed structure shows predominance of sp(2) over sp bonding, while a significant proportion of sp(3) hybrid bonding is also observed. We also calculated a ring distribution and geometrical pore size distribution of the model developed. The latter is compared with that obtained from argon adsorption at 87 K using our recently proposed characterization procedure [4], the finite wall thickness (FWT) model. Further, we determine self-diffusivities of argon and nitrogen in the constructed carbon as functions of loading. It is found that while there is a maximum in the diffusivity with respect to loading, as previously observed by Pikunic et al. [5], diffusivities in the present work are 10 times larger than those obtained in the prior work, consistent with the larger pore size as well as higher porosity of the activated saccharose carbon studied here.

Interactions between the powdery mildew effector BEC1054 and barley proteins identify candidate host targets

There are over 500 candidate secreted effector proteins (CSEPs) or Blumeria effector candidates (BECs) specific to the barley powdery mildew pathogen Blumeria graminis f.sp. hordei. The CSEP/BEC proteins are expressed and predicted to be secreted by biotrophic feeding structures called haustoria. Eight BECs are required for the formation of functional haustoria. These include the RNase-like effector BEC1054 (synonym CSEP0064). In order to identify host proteins targeted by BEC1054, recombinant BEC1054 was expressed in E. coli, solubilized, and used in pull-down assays from barley protein extracts. Many putative interactors were identified by LC-MS/MS after subtraction of unspecific binders in negative controls. Therefore, a directed yeast-2-hybrid assay, developed to measure the effectiveness of the interactions in yeast, was used to validate putative interactors. We conclude that BEC1054 may target several host proteins, including a glutathione-S-transferase, a malate dehydrogenase, and a pathogen-related-5 protein isoform, indicating a possible role for BEC1054 in compromising well-known key players of defense and response to pathogens. In addition, BEC1054 interacts with an elongation factor 1 gamma. This study already suggests that BEC1054 plays a central role in barley powdery mildew virulence by acting at several levels.