An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.     

Structure based virtual screening of ligands to identify cysteinyl leukotriene receptor 1 antagonist

Montelukast and Zafirlukast are known leukotriene receptor antagonists prescribed in asthma treatment. However, these fall short as mono therapy and are frequently used in combination with inhaled glucocorticosteroids with or without long acting beta 2 agonists. Therefore, it is of interest to apply ligand and structure based virtual screening strategies to identify compounds akin to lead compounds Montelukast and Zafirlukast. Hence, compounds with structures having 95% similarity to these compounds were retrieved from NCBI׳s PubChem database. Compounds similar to lead were grouped and docked at the antagonist binding site of cysteinyl leukotriene receptor 1. This exercise identified compounds UNII 70RV86E50Q (Pub Cid 71587778) and Sure CN 9587085 (Pub Cid 19793614) with higher predicted binding compared to Montelukast and Zafirlukast. It is shown that the compound Sure CN 9587085 showed appreciable ligand receptor interaction compared to UNII 70RV86E50Q. Thus, the compound Sure CN 9587085 is selected as a potent antagonist to cysteinyl leukotriene receptor 1 for further consideration in vitro and in vivo validation.     

Structure of a neutral O-specific polysaccharide of the bacterium Providencia alcalifaciens O5.

A neutral polysaccharide containing D-galactose, 2-acetamido-2-deoxy-D-glucose, and 3-acetamido-3,6-dideoxy-D-glucose (Qui3NAc) in the ratios 2:1:1 was obtained by mild acid degradation of lipopolysaccharide of the bacterium Providencia alcalifaciens O5 followed by gel chromatography and ion-exchange chromatography or treatment with anhydrous hydrogen fluoride. On the basis of full acid hydrolysis, methylation, and 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), total correlation spectroscopy (TOCSY), H-detected heteronuclear 1H,13C single-quantum coherence (HSQC), and nuclear Overhauser effect spectroscopy (NOESY), the following structure of the linear tetrasaccharide repeating unit of the polysaccharide was established:     

The identity of the O-specific polysaccharide structure of Citrobacter strains from serogroups O2, O20 and O25 and immunochemical characterisation of C. youngae PCM 1507 (O2a,1b) and related strains

Serological studies using SDS-PAGE and immunoblotting revealed that from five strains that are ascribed to Citrobacter serogroup O2, four strains, PCM 1494, PCM 1495, PCM 1496 and PCM 1507, are reactive with specific anti-Citrobacter O2 serum. In contrast, strain PCM 1573 did not react with anti-Citrobacter O2 serum and, hence, does not belong to serogroup O2. The LPS of Citrobacter youngae O2a,1b (strain PCM 1507) was degraded under mild acidic conditions and the O-specific polysaccharide (OPS) released was isolated by gel chromatography. Sugar and methylation analyses along with (1)H- and (13)C-NMR spectroscopy, including two-dimensional (1)H,(1)H COSY, TOCSY, NOESY and (1)H,(13)C HSQC experiments, showed that the repeating unit of the OPS has the following structure: [structure: see text]. NMR spectroscopic studies demonstrated that Citrobacter werkmanii O20 and C. youngae O25 have the same OPS structure as C. youngae O2. Sugar and methylation analyses of the core oligosaccharide fractions demonstrated structural differences in the lipopolysaccharide core regions of these strains, which may substantiate their classification in different serogroups.     

Structure of a new 2-deoxy-2-[(R)-3-hydroxybutyramido]-D-glucose-containing O-specific polysaccharide from the lipopolysaccharide of Citrobacter gillenii PCM 1542

The O-specific polysaccharide of Citrobacter gillenii PCM 1542 from serotype O-12a,12 b is composed of one residue each of D-glucose, D-GlcNAc, 2-deoxy-2-[(R)-3-hydroxybutyramido]-D-glucose (D-GlcNAcyl) and two GalNAc residues. On the basis of sugar and methylation analyses of the intact and Smith degraded polysaccharides, along with 1D and 2D 1H and 13C NMR spectroscopy, the following structure of the branched pentasaccharide repeating unit of the O-specific polysaccharide was established:This structure differs significantly from that of the O-specific polysaccharide of C. gillenii PCM 1544 from the same serotype O-12a,12 b, which has been established earlier (Kübler-Kielz.shtsls;b, J. et al. Carbohydr. Res. 2001, 331, 331-336). Serological studies confirmed that the two O-antigens are not related and suggested that strains PCM 1542 and 1544 should be classified into different O-serogroups.     

Structure of the O-specific polysaccharide isolated from the lipopolysaccharide of Citrobacter gillenii serotype O12a, 12b strain PCM 1544

A neutral O-specific polysaccharide was isolated from the lipopolysaccharide of Citrobacter gillenii strain PCM 1544, representing serotype O12a,12b. The polysaccharide was studied by sugar and methylation analyses and Smith degradation along with 1H and 13C NMR spectroscopy, including a ROESY experiment. The following structure of the tetrasaccharide repeating unit was established, in which substitution with terminal GlcNAc is approximately 60%. [structure: see text]     

Structure of the O-polysaccharide of Providencia alcalifaciens O19

Studies of the O-polysaccharide chain of the lipopolysaccharide (O-antigen) of Providencia alcalifaciens O19 by sugar and methylation analyses along with NMR spectroscopy, including 2D 1H,1H COSY, TOCSY, NOESY and 1H,13C HSQC experiments, showed that the pentasaccharide repeating unit of the polysaccharide has the following structure: [structure: see text] where Fuc3NAc is 3-acetamido-3,6-dideoxygalactose. The unique structure of the O-antigen and serological data are in consistence with classification of this bacterium in a separate Providencia serogroup.     

The O-polysaccharide of Pseudomonas syringae pv. mori NCPPB 1656 is a beta-(1-->2)-linked homopolymer of L-rhamnose

The O-polysaccharide from the lipopolysaccharide of the phytopathogenic bacterium Pseudomonas syringae pv. mori NCPPB 1656 was studied by sugar analysis along with 1H and 13C NMR spectroscopy and found to be a new beta-(1-->2)-linked homopolymer of L-rhamnose.     

Structure of the O-specific polysaccharide of the lipopolysaccharide of Rahnella aquatilis 95 U003

The O-polysaccharide of Rahnella aquatilis 95 U003 was obtained by mild acid degradation of the lipopolysaccharide and studied by sugar and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, H-detected (1)H,(13)C HSQC and HMQC-TOCSY experiments. The O-polysaccharide was found to have a branched hexasaccharide repeating unit of the following structure:     

Production of destruxins by coprotrophic Beauveria feline no. 7 strain

Beauveria feline No. 7 strain was isolated from the shrewmouse wool and characterized by production of a complex of destruxins cyclodepsipeptides. The strain was shown to produce significant quatities of destruxin B and pseudodestruxin C. The destruxins were found to be able to inhibit formation of biofilms by Pseudomonas aeruginosa ATCC 27833.