Human malarial disease: a consequence of inflammatory cytokine release

Malaria causes an acute systemic human disease that bears many similarities, both clinically and mechanistically, to those caused by bacteria, rickettsia, and viruses. Over the past few decades, a literature has emerged that argues for most of the pathology seen in all of these infectious diseases being explained by activation of the inflammatory system, with the balance between the pro and anti-inflammatory cytokines being tipped towards the onset of systemic inflammation. Although not often expressed in energy terms, there is, when reduced to biochemical essentials, wide agreement that infection with falciparum malaria is often fatal because mitochondria are unable to generate enough ATP to maintain normal cellular function. Most, however, would contend that this largely occurs because sequestered parasitized red cells prevent sufficient oxygen getting to where it is needed. This review considers the evidence that an equally or more important way ATP deficency arises in malaria, as well as these other infectious diseases, is an inability of mitochondria, through the effects of inflammatory cytokines on their function, to utilise available oxygen. This activity of these cytokines, plus their capacity to control the pathways through which oxygen supply to mitochondria are restricted (particularly through directing sequestration and driving anaemia), combine to make falciparum malaria primarily an inflammatory cytokine-driven disease

Extraction, preconcentration and spectrophotometric determination of trace levels of thiosulfate in environmental waters

In the existing study, a new vortex-assisted cloud point extraction (VA-CPE) method was developed for determination of low levels of thiosulfate in environmental waters at 632 nm by spectrophotometry. The method is selectively based on charge-transfer-sensitive ion-pair complex formation of Ag(S2O3)2 3?, which is produced by the reaction of thiosulfate with excess Ag+ ions with toluidine blue (3-amino-7-dimethylamino-2-methylphenazathionium chloride, TB+) and then its extraction into micellar phase of polyethylene glycol 4-tert-octylphenyl ether (Triton X-45) in presence of Na2SO4 as salting-out agent at pH 7.0. All the factors affecting complex formation and VA-CPE efficiency were optimized in detail. Under the optimized conditions, the linear calibration curves for thiosulfate were in the range of 0.2–120 and 5–180 µg L?1 with sensitivity improvement of 81-folds and 15-folds, respectively, as a result of efficient mass transfer obtained by CPE with and without vortex, while it changed in the range of 260–3600 µg L?1 without preconcentration at 642 nm. The limits of detection and quantification of the method for VA-CPE were found to be 0.05 and 0.22 µg L?1, respectively. The precision (expressed as the percent relative standard deviation) was in range of 2.5–4.8% (5, 10 and 25 µg L?1, n: 5). The method accuracy was validated by comparing the results to those of an independent 5,5?-dithiobis(2-aminobenzoic acid) (DTNB) method as well as recovery studies from spiked samples. It has been observed that the results are statistically in a good agreement with those obtained by DTNB method. Finally, the method developed was successfully applied to the preconcentration and determination of trace thiosulfate from environmental waters. © 2017, The Author(s)

An integrative study of a meromictic lake ecosystem in Antarctica

In nature, the complexity and structure of microbial communities varies widely, ranging from a few species to thousands of species, and from highly structured to highly unstructured communities. Here, we describe the identity and functional capacity of microbial populations within distinct layers of a pristine, marine-derived, meromictic (stratified) lake (Ace Lake) in Antarctica. Nine million open reading frames were analyzed, representing microbial samples taken from six depths of the lake size fractionated on sequential 3.0, 0.8 and 0.1 μm filters, and including metaproteome data from matching 0.1 μm filters. We determine how the interactions of members of this highly structured and moderately complex community define the biogeochemical fluxes throughout the entire lake. Our view is that the health of this delicate ecosystem is dictated by the effects of the polar light cycle on the dominant role of green sulfur bacteria in primary production and nutrient cycling, and the influence of viruses/phage and phage resistance on the cooperation between members of the microbial community right throughout the lake. To test our assertions, and develop a framework applicable to other microbially driven ecosystems, we developed a mathematical model that describes how cooperation within a microbial system is impacted by periodic fluctuations in environmental parameters on key populations of microorganisms. Our study reveals a mutualistic structure within the microbial community throughout the lake that has arisen as the result of mechanistic interactions between the physico-chemical parameters and the selection of individual members of the community. By exhaustively describing and modelling interactions in Ace Lake, we have developed an approach that may be applicable to learning how environmental perturbations affect the microbial dynamics in more complex aquatic systems