Transcriptomic Analysis Reveals a Differential Gene Expression Profile Between Two Sunflower Inbred Lines with Different Ability to Tolerate Water Stress

Plant Molecular Biology Reporter - Although sunflower (Helianthus annuus L.) is categorized as a medium drought-sensitive crop, in a changing climate scenario and/or with the onset of early...     

Metabolic regulation analysis of an ethanologenic <Emphasis Type="Italic">Escherichia coli</Emphasis> strain based on RT-PCR and enzymatic activities

Background  

A metabolic regulation study was performed, based upon measurements of enzymatic activities, fermentation performance, and RT-PCR analysis of pathways related to central carbon metabolism, in an ethanologenic Escherichia coli strain (CCE14) derived from lineage C. In comparison with previous engineered strains, this E coli derivative has a higher ethanol production rate in mineral medium, as a result of the elevated heterologous expression of the chromosomally integrated genes encoding PDC _Zm and ADH _Zm (pyruvate decarboxylase and alcohol dehydrogenase from Zymomonas mobilis). It is suggested that this behavior might be due to lineage differences between E. coli W and C.     

Metabolic engineering for the production of shikimic acid in an evolved <Emphasis Type="Italic">Escherichia coli</Emphasis> strain lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system

Background  

Shikimic acid (SA) is utilized in the synthesis of oseltamivir-phosphate, an anti-influenza drug. In this work, metabolic engineering approaches were employed to produce SA in Escherichia coli strains derived from an evolved strain (PB12) lacking the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS^-) but with capacity to grow on glucose. Derivatives of PB12 strain were constructed to determine the effects of inactivating aroK, aroL, pykF or pykA and the expression of plasmid-coded genes aroG ^fbr, tktA, aroB and aroE, on SA synthesis.     

The genetic diversity of Plasmodium vivax populations

Little is known of the genetic diversity and population structure of Plasmodium vivax, a debilitating and highly prevalent malaria parasite of humans. This article reviews the known polymorphic genetic markers, summarizes current data on the population structure of this parasite and discusses future prospects for using knowledge of the genetic diversity to improve control measures.     

The EutQ and EutP proteins are novel acetate kinases involved in ethanolamine catabolism: physiological implications for the function of the ethanolamine metabolosome in Salmonella enterica

Salmonella enterica catabolizes ethanolamine inside a compartment known as the metabolosome. The ethanolamine utilization (eut) operon of this bacterium encodes all functions needed for the assembly and function of this structure. To date, the roles of EutQ and EutP were not known. Herein we show that both proteins have acetate kinase activity and that EutQ is required during anoxic growth of S. enterica on ethanolamine and tetrathionate. EutP and EutQ‐dependent ATP synthesis occurred when enzymes were incubated with ADP, Mg(II) ions and acetyl‐phosphate. EutQ and EutP also synthesized acetyl‐phosphate from ATP and acetate. Although EutP had acetate kinase activity, ΔeutP strains lacked discernible phenotypes under the conditions where ΔeutQ strains displayed clear phenotypes. The kinetic parameters indicate that EutP is a faster enzyme than EutQ. Our evidence supports the conclusion that EutQ and EutP represent novel classes of acetate kinases. We propose that EutQ is necessary to drive flux through the pathway under physiological conditions, preventing a buildup of acetaldehyde. We also suggest that ATP generated by these enzymes may be used as a substrate for EutT, the ATP‐dependent corrinoid adenosyltransferase and for the EutA ethanolamine ammonia‐lyase reactivase.     

Novel insights into capillary vessel basement membrane damage by snake venom hemorrhagic metalloproteinases: a biochemical and immunohistochemical study

The hemorrhagic activity characteristic of viperid snake envenomations is due to the action of venom metalloproteinases (SVMPs) on the capillary vessel basement membrane (BM). This study compared the action of two SVMPs on BM in vitro (degradation of Matrigel) and in vivo (immunohistochemical assessment of BM markers in mouse gastrocnemius muscle). SVMPs BaP1 (belonging to the P-I class) and jararhagin (of the P-III class) had a similar proteolytic activity on azocasein and degraded Matrigel with a slightly different cleavage pattern, since BaP1 exerted a limited proteolysis of both laminin and nidogen, whereas jararhagin predominantly degraded nidogen. In contrast with this pattern of limited proteolysis of BM proteins observed in vitro, immunohistochemical analysis of laminin, nidogen and type IV collagen, as well as of the endothelial cell marker VEGFR-2, in the hemorrhagic areas in the muscle, revealed a pronounced reduction in the immunostaining of these three BM components, associated with a loss of the endothelial cell marker. BM of muscle fibers was affected to a lesser extent. In conclusion, in vitro results demonstrated that SVMPs induce a pattern of limited proteolysis on BM components. The drastic loss of these antigens in affected capillaries in vivo is likely to depend on the combination of limited proteolysis of BM and the action of hemodynamic biophysical forces, previously shown to play a role in SVMP-induced capillary damage, which may cause a mechanical disruption of BM structure.     

Optimization of Culturing Conditions of a Strain of Phytophthora capsici Pathogenic to Habanero Pepper (Capsicum chinense)

Phytophthora capsici is an oomycete known as the causal agent of wilting disease in Capsicum spp., which causes rotting of roots, crowns, stems, leaves and fruits. To date, little is known about the production of phytotoxic metabolites by P. capsici or their role in the infection process. As part of a project directed towards the isolation and identification of phytotoxins produced by a strain of P. capsici pathogenic to habanero pepper (Capsicum chinense), we have evaluated the effect of factors such as aeration, light and culture medium on the production of mycelium and phytotoxic metabolites by P. capsici. The results showed that culturing P. capsici in potato dextrose broth (PDB) containing habanero pepper leaf infusion, in the dark and under still conditions, results in a high production of mycelium and a high phytotoxicity of the culture filtrate, in the shortest period of time.