Purification and Properties of a Glycerol Ester Hydrolase (Lipase) from Propionibacterium shermanii

An intracellular glycerol ester hydrolase (lipase) from Propionibacterium shermanii was recovered from cell-free extracts and purified by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography on diethylaminoethylcellulose. Maximum enzyme activity was observed at pH 7.2 and 47 C when an emulsion of tributyrin was used as substrate. The enzyme was stable between pH 5.5 and 8. Heating the enzyme solution at 45 C for 10 min resulted in a 75% decrease in activity. Maximum rate of hydrolysis of triglycerides was observed on tripropionin, followed in order by tributyrin, tricaproin, and tricaprylin. The lipase was strongly inhibited by mercury and arsenicals, but specific sulfhydryl reagents had little or no inhibiting effect on the enzyme activity. The enzyme also showed some esterase activity, but the hydrolysis of substrates in solution was small as compared to the hydrolysis of substrates in emulsion.     

Outcomes among children and adults at risk of severe dengue in Sri Lanka: Opportunity for outpatient case management in countries with high disease burden

BackgroundHealthcare systems in dengue-endemic countries are often overburdened due to the high number of patients hospitalized according to dengue management guidelines. We systematically evaluated clinical outcomes in a large cohort of patients hospitalized with acute dengue to support triaging of patients to ambulatory versus inpatient management in the future.Methods/Principal findingsFrom June 2017- December 2018, we conducted surveillance among children and adults with fever within the prior 7 days who were hospitalized at the largest tertiary-care (1,800 bed) hospital in the Southern Province, Sri Lanka. Patients who developed platelet count ≤100,000/μL (threshold for hospital admission in Sri Lanka) and who met at least two clinical criteria consistent with dengue were eligible for enrollment. We confirmed acute dengue by testing sera collected at enrollment for dengue NS1 antigen or IgM antibodies. We defined primary outcomes as per the 1997 and 2009 World Health Organization (WHO) classification criteria: dengue hemorrhagic fever (DHF; WHO 1997), dengue shock syndrome (DSS; WHO 1997), and severe dengue (WHO 2009). Overall, 1064 patients were confirmed as having acute dengue: 318 (17.4%) by NS1 rapid antigen testing and 746 (40.7%) by IgM antibody testing. Of these 1064 patients, 994 (93.4%) were adults ≥18 years and 704 (66.2%) were male. The majority (56, 80%) of children and more than half of adults (544, 54.7%) developed DHF during hospitalization, while 6 (8.6%) children and 22 (2.2%) adults developed DSS. Overall, 10 (14.3%) children and 113 (11.4%) adults developed severe dengue. A total of 2 (0.2%) patients died during hospitalization.ConclusionsOne-half of patients hospitalized with acute dengue progressed to develop DHF and a very small number developed DSS or severe dengue. Developing an algorithm for triaging patients to ambulatory versus inpatient management should be the future goal to optimize utilization of healthcare resources in dengue-endemic countries.     

Multiscale Investigation of Sodium-Ion Battery Anodes: Analytical Techniques and Applications

The anode/electrolyte interface behavior, and by extension, the overall cell performance of sodium-ion batteries is determined by a complex interaction of processes that occur at all components of the electrochemical cell across a wide range of size- and timescales. Single-scale studies may provide incomplete insights, as they cannot capture the full picture of this complex and intertwined behavior. Broad, multiscale studies are essential to elucidate these processes. Within this perspectives article, several analytical and theoretical techniques are introduced, and described how they can be combined to provide a more complete and comprehensive understanding of sodium-ion battery (SIB) performance throughout its lifetime, with a special focus on the interfaces of hard carbon anodes. These methods target various length- and time scales, ranging from micro to nano, from cell level to atomistic structures, and account for a broad spectrum of physical and (electro)chemical characteristics. Specifically, how mass spectrometric, microscopic, spectroscopic, electrochemical, thermodynamic, and physical methods can be employed to obtain the various types of information required to understand battery behavior will be explored. Ways are then discussed how these methods can be coupled together in order to elucidate the multiscale phenomena at the anode interface and develop a holistic understanding of their relationship to overall sodium-ion battery function.     

The abundance of an invasive freshwater snail Tarebia granifera (Lamarck, 1822) in the Nseleni River,South Africa

The invasive freshwater snail Tarebia granifera (Lamarck, 1822) was first reported in South Africa in 1999 and it has become widespread across the country, with some evidence to suggest that it reduces benthic macroinvertebrate biodiversity. The current study aimed to identify the primary abiotic drivers behind abundance patterns of T. granifera, by comparing the current abundance of the snail in three different regions, and at three depths, of the highly modified Nseleni River in KwaZulu-Natal, South Africa. Tarebia granifera was well established throughout the Nseleni River system, with an overall preference for shallow waters and seasonal temporal patterns of abundance. Although it is uncertain what the ecological impacts of the snail in this system are, its high abundances suggest that it should be controlled where possible and prevented from invading other systems in the region.     

Environmental stresses inhibit splicing in the aquatic fungus Blastocladiella emersonii

Background  

Exposure of cells to environmental stress conditions can lead to the interruption of several intracellular processes, in particular those performed by macromolecular complexes such as the spliceosome.     

From Rapid Place Learning to Behavioral Performance: A Key Role for the Intermediate Hippocampus

Rapid place encoding by hippocampal neurons, as reflected by place-related firing, has been intensely studied, whereas the substrates that translate hippocampal place codes into behavior have received little attention. A key point relevant to this translation is that hippocampal organization is characterized by functional–anatomical gradients along the septotemporal axis: Whereas the ability of hippocampal neurons to encode accurate place information declines from the septal to temporal end, hippocampal connectivity to prefrontal and subcortical sites that might relate such place information to behavioral-control processes shows an opposite gradient. We examined in rats the impact of selective lesions to relevant parts of the hippocampus on behavioral tests requiring place learning (watermaze procedures) and on in vivo electrophysiological models of hippocampal encoding (long-term potentiation [LTP], place cells). We found that the intermediate hippocampus is necessary and largely sufficient for behavioral performance based on rapid place learning. In contrast, a residual septal pole of the hippocampus, although displaying intact electrophysiological indices of rapid information encoding (LTP, precise place-related firing, and rapid remapping), failed to sustain watermaze performance based on rapid place learning. These data highlight the important distinction between hippocampal encoding and the behavioral performance based on such encoding, and suggest that the intermediate hippocampus, where substrates of rapid accurate place encoding converge with links to behavioral control, is critical to translate rapid (one-trial) place learning into navigational performance.     

The human collagen beta(1-O)galactosyltransferase,GLT25D1, is a soluble endoplasmic reticulum localized protein

Background  

Glycosyl transferases transfer glycosyl groups onto their substrate. Localization partially defines their function. Glycosyl transferase 25 domain 1 (GLT25D1) was recently shown to have galactosyltransferase activity towards collagens and another well known substrate, mannose binding lectin (MBL). To gain more insight in the role of galactosylation of lysines in the Gly-X-Lys repeats of collagenous proteins, we investigated the subcellular localization of GLT25D1.     

Early Differences in Dorsal Hippocampal Metabolite Levels in Males But Not Females in a Transgenic Rat Model of Alzheimer’s Disease

McGill-R-Thy1-APP rats express the human amyloid precursor protein carrying the Swedish and Indiana mutations. We examined the neurochemical content of the dorsal hippocampus in three-months-old male and female transgenic rats and healthy age- and gender-matched controls using in vivo ¹H MRS in order to assess early metabolite alterations and whether these were similar for both genders. Whereas male and female controls had similar levels of all metabolites, differences were evident between male and female McGill-R-Thy1-APP rats. Compared with McGill-R-Thy1-APP females, McGill-R-Thy1-APP males had lower levels of myo-inositol and N-acetylaspartate (NAA). No differences in metabolite levels were evident when female control and McGill-R-Thy1-APP rats were compared, whereas McGill-R-Thy1-APP males had lower levels of glutamate, NAA and total choline compared with male controls. In addition to metabolite concentrations, metabolite ratios are reported as these are widely used. The results from this preliminary study demonstrate early metabolite alterations in the dorsal hippocampus of males in this rat model of Alzheimer’s disease, and imply that very early possible neurochemical markers of the disease are different for males and females.     

Tauroursodeoxycholic acid increases neural stem cell pool and neuronal conversion by regulating mitochondria-cell cycle retrograde signaling

The low survival and differentiation rates of stem cells after either transplantation or neural injury have been a major concern of stem cell-based therapy. Thus, further understanding long-term survival and differentiation of stem cells may uncover new targets for discovery and development of novel therapeutic approaches. We have previously described the impact of mitochondrial apoptosis-related events in modulating neural stem cell (NSC) fate. In addition, the endogenous bile acid, tauroursodeoxycholic acid (TUDCA) was shown to be neuroprotective in several animal models of neurodegenerative disorders by acting as an anti-apoptotic and anti-oxidant molecule at the mitochondrial level. Here, we hypothesize that TUDCA might also play a role on NSC fate decision. We found that TUDCA prevents mitochondrial apoptotic events typical of early-stage mouse NSC differentiation, preserves mitochondrial integrity and function, while enhancing self-renewal potential and accelerating cell cycle exit of NSCs. Interestingly, TUDCA prevention of mitochondrial alterations interfered with NSC differentiation potential by favoring neuronal rather than astroglial conversion. Finally, inhibition of mitochondrial reactive oxygen species (mtROS) scavenger and adenosine triphosphate (ATP) synthase revealed that the effect of TUDCA is dependent on mtROS and ATP regulation levels. Collectively, these data underline the importance of mitochondrial stress control of NSC fate decision and support a new role for TUDCA in this process.     

Palaeo‐ecology of the Gap and Coturaundee Ranges,western New South Wales,using stick‐nest rat (Leporillus spp.) (Muridae) middens

Pollen, plant and animal macrofossils recovered from nine Leporillus spp. (Muridae) middens found in the Gap and Coturaundee Ranges, western New South Wales were examined. By comparing current vegetation, pollen from modern surface samples and pollen from midden samples, general vegetation characteristics over the last 6500 years BP were reconstructed. Evidence shows that a greater shrub cover was apparent between 6500 and 5200 BP , while other aspects of the vegetation cover were similar to present. An increase in tree pollen, possibly indicating greater tree cover, occurred around 3400–2600 BP , while vegetation in the last 1300 years was similar to present. These interpretations, particularly from the older samples, are tentative due to spatial and temporal limitations. Animal macrofossils from the middens indicate that several mammal species now extinct or uncommon in western New South Wales have occurred in the area in the past 3000 years. This study also confirms that reconstruction of vegetation from Leporillus spp. midden evidence should be seen as separate ‘snapshots’, rather than continuous records over a stratigraphically defined timescale.