Tumor necrosis factor-alpha inhibits expression of CTP:phosphocholine cytidylyltransferase

We investigated the effects of tumor necrosis factor alpha (TNFalpha), a key cytokine involved in inflammatory lung disease, on phosphatidylcholine (PtdCho) biosynthesis in a murine alveolar type II epithelial cell line (MLE-12). TNFalpha significantly inhibited [(3)H]choline incorporation into PtdCho after 24 h of exposure. TNFalpha reduced the activity of CTP:phosphocholine cytidylyltransferase (CCT), the rate-regulatory enzyme within the CDP-choline pathway, by 40% compared with control, but it did not alter activities of choline kinase or cholinephosphotransferase. Immunoblotting revealed that TNFalpha inhibition of CCT activity was associated with a uniform decrease in the mass of CCTalpha in total cell lysates, cytosolic, microsomal, and nuclear subfractions of MLE cells. Northern blotting revealed no effects of the cytokine on steady-state levels of CCTalpha mRNA, and CCTbeta mRNA was not detected. Incorporation of [(35)S]methionine into immunoprecipitable CCTalpha protein in pulse and pulse-chase studies revealed that TNFalpha did not alter de novo synthesis of enzyme, but it substantially accelerated turnover of CCTalpha. Addition of N-acetyl-Leu-Leu-Nle-CHO (ALLN), the calpain I inhibitor, or lactacystin, the 20 S proteasome inhibitor, blocked the inhibition of PtdCho biosynthesis mediated by TNFalpha. TNFalpha-induced degradation of CCTalpha protein was partially blocked by ALLN or lactacystin. CCT was ubiquitinated, and ubiquitination increased after TNFalpha exposure. m-Calpain degraded both purified CCT and CCT in cellular extracts. Thus, TNFalpha inhibits PtdCho synthesis by modulating CCT protein stability via the ubiquitin-proteasome and calpain-mediated proteolytic pathways.     

The use of glass wool as an attachment surface for studying phenotypic changes in Pseudomonas aeruginosa biofilms by two-dimensional gel electrophoresis

Two-dimensional polyacrylamide gel electrophoresis was used to demonstrate phenotypic differences between Pseudomonas aeruginosa biofilm cells and the planktonic counterpart cells under defined culture conditions. Glass wool was used as a substratum for cell attachment as it affords a large surface-to-volume ratio (1 g with a mean diameter of 15 microns = 1300 cm2), supports the growth of biofilms, allows for free movement of cells between the inter-strand spaces, and it facilitates the exchange of nutrients and oxygen. It also allows for the separation of the biofilm biomass from the surrounding surface influenced planktonic (SIP) cells for further characterization. Comparative analysis of the respective proteomes indicated striking differences in the protein patterns of planktonic, biofilm and SIP cells. We selected 41 proteins, the levels of which varied in a significant and reproducible way in the respective protein profiles. In the biofilm cells, a general up-regulation of the spots was seen, but in SIP cells expression of these spots were generally down-regulated. Altogether six unique proteins were seen in the planktonic cells, while the biofilm and SIP cells contained five and two unique proteins, respectively. Glass wool, therefore, appears to be an ideal attachment surface for the study of biofilm development.     

The cold-shock stress response in Mycobacterium smegmatis induces the expression of a histone-like protein

The response of Mycobacterium smegmatis to a cold shock was investigated by monitoring changes in both growth and cellular protein composition of the organism. The nature of the cellular response was influenced by the magnitude of the temperature reduction, with the shock from 37 degrees C to 10 degrees C having the most widespread effect on growth, metabolism and protein composition. This 27 degrees C temperature reduction was associated with a lag period of 21-24 h before increases were seen in all the measured cellular activities. The response to cold shock was adaptive, with growth resuming after this period, albeit at a 50-fold slower rate. The synthesis of at least 15 proteins was induced during the lag period. Two distinct patterns of cold-induced synthesis were apparent, namely transient and continuous, indicating the production of both cold-induced and cold-acclimation proteins. One of these cold-shock proteins, CipMa, was identified as the histone-like protein, Hlp, of M. smegmatis, which is also induced during anaerobic-induced dormancy. The corresponding gene demonstrated transient, cold-inducible expression with a five- to sevenfold increase in mRNA occurring 9-12 h after temperature shift. Although bacterial survival was unaffected, CipMa/Hlp knock-out mutants were unable to adapt metabolically to the cold shock and resume growth, thus indicating a key role for CipMa in the cold-shock response.     

New species of Aspergillus producing sterigmatocystin.

A number of species belonging to the genus Aspergillus were evaluated for their toxicity to ducklings and the ability to produce sterigmatocystin. Three new species capable of producing sterigmatocystin were found, namely, Aspergillus aurantio-brunneus, Aspergillus quadrilineatus, and Aspergillus ustus. All three were toxic to ducklings. The production of sterigmatocystin by Aspergillus rugulosus was confirmed, and the toxicity of Aspergillus stellatus and Aspergillus multicolor is described.     

Entomopathogenic nematodes from north-eastern South Africa and their virulence against false codling moth,Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

A survey was undertaken to determine the diversity and frequency of endemic entomopathogenic nematodes (EPN) in subtropical regions in the Mpumalanga, Limpopo and KwaZulu-Natal provinces of South Africa. A total of 136 soil samples were randomly taken from cultivated and uncultivated habitats, including subtropical fruit tree orchards (avocado, litchi, macadamia, mango and guava) and adjoining natural vegetation. EPNs were isolated from 14 samples (10.3%) by means of baiting with Tenebrio molitor larvae. Heterorhabditis was the most common genus isolated from 12 samples, whereas only two Steinernema species were isolated. The most common Heterorhabditis isolated were Heterorhabditis noenieputensis and H. zealandica, which were both isolated from four samples each. The present report is the first occurrence of H. taysearae and H. baujardi in South Africa. The two Steinernema species are both unknown species. Laboratory bioassays were conducted to determine the potential of seven native EPN isolates to control the false codling moth (Thaumatotibia leucotreta) (FCM). Last instar FCM larvae were found to be most susceptible to S. yirgalemense (157-C), H. zealandica (WS 23) and Steinernema litchii (WS9), when exposed to 50 IJs/50?µ? water for 48?h, causing 100%, 94.2% and 93.5% mortality, respectively.     

Lipid Deficiencies, Leukocytosis, Brittle Skin—a Lethal Syndrome Caused by a Recessive Mutation, Edematous (OED), in the Mouse

A new neonatal lethal mutation in the mouse with pleiotropic effects, edematous (oed), arose spontaneoutosomal recessive mode of inheritance. The external phenotypic characteristics include a generally bloated appearance, shiny celophane-like skin, and distal hematomata of the extremities. Internally, no gross or histological abnormalities could be identified, with the exception of a striking leukocytosis. Biochemical analysis revealed a severe disturbance of lipid metabolism. Deficiencies in the VLDL, LDL, and the HDL lipoprotein fractions have been found in the mutant plasma. In addition, all serum lipids are markedly decreased. However, in the mutant liver, only triglycerides are significantly decreased; total liver cholesterol and phospholipid values are within normal limits. The primary biochemical defect as well as the causal relationship between the striking abnormalities of lipid metabolism and those of skin and blood are unknown at this time.     

A Risk Prediction Model for the Assessment and Triage of Women with Hypertensive Disorders of Pregnancy in Low-Resourced Settings: The miniPIERS (Pre-eclampsia Integrated Estimate of RiSk) Multi-country Prospective Cohort Study

Background

Pre-eclampsia/eclampsia are leading causes of maternal mortality and morbidity, particularly in low- and middle- income countries (LMICs). We developed the miniPIERS risk prediction model to provide a simple, evidence-based tool to identify pregnant women in LMICs at increased risk of death or major hypertensive-related complications.

Methods and Findings

From 1 July 2008 to 31 March 2012, in five LMICs, data were collected prospectively on 2,081 women with any hypertensive disorder of pregnancy admitted to a participating centre. Candidate predictors collected within 24 hours of admission were entered into a step-wise backward elimination logistic regression model to predict a composite adverse maternal outcome within 48 hours of admission. Model internal validation was accomplished by bootstrapping and external validation was completed using data from 1,300 women in the Pre-eclampsia Integrated Estimate of RiSk (fullPIERS) dataset. Predictive performance was assessed for calibration, discrimination, and stratification capacity. The final miniPIERS model included: parity (nulliparous versus multiparous); gestational age on admission; headache/visual disturbances; chest pain/dyspnoea; vaginal bleeding with abdominal pain; systolic blood pressure; and dipstick proteinuria. The miniPIERS model was well-calibrated and had an area under the receiver operating characteristic curve (AUC ROC) of 0.768 (95% CI 0.735–0.801) with an average optimism of 0.037. External validation AUC ROC was 0.713 (95% CI 0.658–0.768). A predicted probability ≥25% to define a positive test classified women with 85.5% accuracy. Limitations of this study include the composite outcome and the broad inclusion criteria of any hypertensive disorder of pregnancy. This broad approach was used to optimize model generalizability.

Conclusions

The miniPIERS model shows reasonable ability to identify women at increased risk of adverse maternal outcomes associated with the hypertensive disorders of pregnancy. It could be used in LMICs to identify women who would benefit most from interventions such as magnesium sulphate, antihypertensives, or transportation to a higher level of care. Please see later in the article for the Editors'' Summary     

THE EFFECT OF SUBLETHAL CONCENTRATIONS OF NATURAL SUSPENDED SILT ON ROUTINE OXYGEN CONSUMPTION BY MOZAMBIQUE TILAPIA (OREOCHROMIS MOSSAMBICUS)

Summary

Exposure of adult Oreochromismossambicusto sublethal concentrations (5 to 20 g silt ?^?1) of natural silt from the Phalaborwa Barrage altered routine oxygen consumption by causing increased rates of oxygen consumption. This indicates that sublethal levels of suspended silt result in a significant (p<0.05) increase in oxygen consumption by the exposed fish due to an increase in metabolic rate associated with increased activity and stress. Any species unable to compensate for this increase in energy expenditure over time would not be able to sustain itself.     

Study of Hepatocytes Polyploidization Peculiarities in Cholestatic Liver of Adult Rats

According to the literature, different mechanisms and kinetics proceeding of regenerative growth has been established using the basic models of liver regeneration (after resection or chemically induced). Hence, in order to determine general regularities of the adaptive-compensatory processes in various pathological conditions, the processes taking place in the cholestatic liver of adult white rats during the first four days after common bile duct ligation have been studied. It has been shown that in cholestatic liver, compensatory-adaptive processes take place with different kinetics compared to those after resection. In particular, in response to the increased functional load caused by destructive processes during cholestasis, the liver, at an early stage, responds by simple division of high ploidy (binuclear tetraploid) cells and further provides their quantitative increase. The difference between the processes taking place in cholestatic and resected liver is more expressed on the third and fourth day after common bile duct ligation. In particular, 4c cells are still highest in cholestatic liver, while all ploidy cells are present in equal numbers in the regenerated liver after resection. This fact of compensatory growth characteristic for reparative regeneration was not detected in cholestatic liver at the mentioned date.     

7. REVIEWS AND RECORDS

Evidence from the Northern Hemisphere and simple theoretical models both predict that climate change could force southern African birds to undergo poleward range shifts. We document the chronology and habitat use of 18 regionally indigenous bird species that colonised the extreme south-western corner of Africa after the late 1940s. This incorporates a period of almost four decades of observed regional warming in the Western Cape, South Africa. Observations of these colonisation events concur with a 'climate change' explanation, assuming extrapolation of Northern Hemisphere results and simplistic application of theory. However, on individual inspection, all bar one may be more parsimoniously explained by direct anthropogenic changes to the landscape than by the indirect effects of climate change. Indeed, no a priori predictions relating to climate change, such as colonisers being small and/or originating in nearby arid shrublands, were upheld. This suggests that observed climate changes have not yet been sufficient to trigger extensive shifts in the ranges of indigenous birds in this region, or that a priori assumptions are incorrect. Either way, this study highlights the danger of naïve attribution of range changes to climate change, even if those range changes accord with the predictions of climate-change models. Nonetheless, studies of artificially enriched faunas, such as that of the Cape Peninsula, and the dynamics of these observed range shifts, may provide insight into processes likely to take place should climate change trigger significant poleward movement by Southern Hemisphere birds.