Growth performance, haematology and serum biochemistry of African catfish (Clarias gariepinus) fingerlings fed graded levels of dietary fumonisin B1

Fingerlings of Clarias gariepinus were used to evaluate the effect of dietary fumonisin B₁ (FB₁), a mycotoxin produced by Fusarium verticillioides, on growth, haematological and serum biochemical parameters. The fingerlings were sorted, weighed and randomly stocked in 16 plastic tanks at the rate of 20 fingerlings per tank. Fusarium-cultured maize grains containing FB₁ were used to formulate three diets containing approximately 5.0, 10.0 and 15.0 mg FB₁/kg, constituting diets 2, 3, and 4 respectively. These three diets, plus diet 1, which contained non-Fusarium cultured maize grains that served as the control, were used in a 6-week feeding trial. The final weight gains by the fingerlings were significantly (P?<?0.05) influenced by FB₁. The final weights of the fingerlings fed diets 2, 3 and 4 ranged from 70.07 to 87.10% of the controls. The haematocrit, erythrocytes, haemoglobin, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and the serum protein constituents (total protein, albumin and globulin) values significantly (P?<?0.05) decreased, while the leucocytes, MCV and MCH increased significantly (P?<?0.05) with increase in the dietary FB₁. The total serum protein values of the fingerlings fed diets 2, 3 and 4 were 34.53, 39.42 and 50.17% lower than the total serum protein values of those fed the control diet. These results indicate that Fusarium-contaminated diets containing about 5.0 mg or more FB₁/kg reduced weight gain and significantly altered haematological parameters and serum protein constituents in the fingerlings. These may have a significant impact on physiological activities and may be vital in immunosuppression in the fingerlings with a strong negative impact on subsequent performance of the fish.     

Functional Characterization of Pseudomonas Contact Dependent Growth Inhibition (CDI) Systems

Contact-dependent inhibition (CDI) toxins, delivered into the cytoplasm of target bacterial cells, confer to host strain a significant competitive advantage. Upon cell contact, the toxic C-terminal region of surface-exposed CdiA protein (CdiA-CT) inhibits the growth of CDI^- bacteria. CDI⁺ cells express a specific immunity protein, CdiI, which protects from autoinhibition by blocking the activity of cognate CdiA-CT. CdiA-CT are separated from the rest of the protein by conserved peptide motifs falling into two distinct classes, the “E. coli”- and “Burkholderia-type”. CDI systems have been described in numerous species except in Pseudomonadaceae. In this study, we identified functional toxin/immunity genes linked to CDI systems in the Pseudomonas genus, which extend beyond the conventional CDI classes by the variability of the peptide motif that delimits the polymorphic CdiA-CT domain. Using P. aeruginosa PAO1 as a model, we identified the translational repressor RsmA as a negative regulator of CDI systems. Our data further suggest that under conditions of expression, P. aeruginosa CDI systems are implicated in adhesion and biofilm formation and provide an advantage in competition assays. All together our data imply that CDI systems could play an important role in niche adaptation of Pseudomonadaceae.     

A Cost-Effectiveness Analysis of a Program to Control Rheumatic Fever and Rheumatic Heart Disease in Pinar del Rio,Cuba

Background

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) persist in many low- and middle-income countries. To date, the cost-effectiveness of population-based, combined primary and secondary prevention strategies has not been assessed. In the Pinar del Rio province of Cuba, a comprehensive ARF/RHD control program was undertaken over 1986 – 1996. The present study analyzes the cost-effectiveness of this Cuban program.

Methods and Findings

We developed a decision tree model based on the natural history of ARF/RHD, comparing the costs and effectiveness of the 10-year Cuban program to a “do nothing” approach. Our population of interest was the cohort of children aged 5 – 24 years resident in Pinar del Rio in 1986. We assessed costs and health outcomes over a lifetime horizon, and we took the healthcare system perspective on costs but did not apply a discount rate. We used epidemiologic, clinical, and direct medical cost inputs that were previously collected for publications on the Cuban program. We estimated health gains as disability-adjusted life years (DALYs) averted using standard approaches developed for the Global Burden of Disease studies. Cost-effectiveness acceptability thresholds were defined by one and three times per capita gross domestic product per DALY averted. We also conducted an uncertainty analysis using Monte Carlo simulations and several scenario analyses exploring the impact of alternative assumptions about the program’s effects and costs. We found that, compared to doing nothing, the Cuban program averted 5051 DALYs (1844 per 100,000 school-aged children) and saved $7,848,590 (2010 USD) despite a total program cost of $202,890 over 10 years. In the scenario analyses, the program remained cost saving when a lower level of effectiveness and a reduction in averted years of life lost were assumed. In a worst-case scenario including 20-fold higher costs, the program still had a 100% of being cost-effective and an 85% chance of being cost saving.

Conclusions

A 10-year program to control ARF/RHD in Pinar del Rio, Cuba dramatically reduced morbidity and premature mortality in children and young adults and was cost saving. The results of our analysis were robust to higher program costs and more conservative assumptions about the program’s effectiveness. It is possible that the program’s effectiveness resulted from synergies between primary and secondary prevention strategies. The findings of this study have implications for non-communicable disease policymaking in other resource-limited settings.     

Expression of the HSV-1 capsid protein VP19C in Escherichia coli: a single amino acid change overcomes an expression block of the full-length polypeptide

The herpesvirus triplex is a key structural feature of the capsids of these viruses. It is composed of a hetero-trimer of one molecule of VP19C and two molecules of VP23. It acts to stabilize capsid shells by connecting the capsomeric subunits together. Although it has been possible to over-express in Escherichia coli and purify one component of the triplex, VP23; this has not been the case with VP19C. Because an N-terminal polypeptide of VP19C could be expressed and purified using a GST affinity tag, a directed mutagenic approach was used to determine the region of VP19C that caused the block in expression of the full-length protein. The region was mapped to reside between VP19C amino acids 145 and 150 using truncation gene fusions and subsequently a single amino acid, R146 was identified which when changed to alanine, allowed stable expression and accumulation of VP19C. This change does not affect the biological function of VP19C. Finally using this altered VP19C, co-expression of the triplex proteins in the same cell has been achieved making it now possible to purify this complex for biophysical and structural studies.     

Hypersensitivity of mtDNA-depleted cells to staurosporine-induced apoptosis: roles of Bcl-2 downregulation and cathepsin B

We show that mitochondrial DNA (mtDNA)-depleted 143B cells are hypersensitive to staurosporine-induced cell death as evidenced by a more pronounced DNA fragmentation, a stronger activation of caspase-3, an enhanced poly(ADP-ribose) polymerase-1 (PARP-1) cleavage, and a more dramatic cytosolic release of cytochrome c. We also show that B-cell CLL/lymphoma-2 (Bcl-2), B-cell lymphoma extra large (Bcl-X(L)), and myeloid cell leukemia-1 (Mcl-1) are constitutively less abundant in mtDNA-depleted cells, that the inhibition of Bcl-2 and Bcl-X(L) can sensitize the parental cell line to staurosporine-induced apoptosis, and that overexpression of Bcl-2 or Bcl-X(L) can prevent the activation of caspase-3 in ρ(0)143B cells treated with staurosporine. Moreover, the inactivation of cathepsin B with CA074-Me significantly reduced cytochrome c release, caspase-3 activation, PARP-1 cleavage, and DNA fragmentation in mtDNA-depleted cells, whereas the pan-caspase inhibitor failed to completely prevent PARP-1 cleavage and DNA fragmentation in these cells, suggesting that caspase-independent mechanisms are responsible for cell death even if caspases are activated. Finally, we show that cathepsin B is released in the cytosol of ρ(0) cells in response to staurosporine, suggesting that the absence of mitochondrial activity leads to a facilitated permeabilization of lysosomal membranes in response to staurosporine.     

The SLP-76 Src homology 2 domain is required for T cell development and activation

The adapter protein Src homology 2 (SH2) domain-containing leukocyte protein of 76 kDa (SLP-76) is critical for multiple aspects of T cell development and function. Through its protein-binding domains, SLP-76 serves as a platform for the assembly of multiple enzymes and adapter proteins that function together to activate second messengers required for TCR signal propagation. The N terminus of SLP-76, which contains three tyrosines that serve as docking sites for SH2 domain-containing proteins, and the central proline-rich region of SLP-76 have been well studied and are known to be important for both thymocyte selection and activation of peripheral T cells. Less is known about the function of the C-terminal SH2 domain of SLP-76. This region inducibly associates with ADAP and HPK1. Combining regulated deletion of endogenous SLP-76 with transgenic expression of a SLP-76 SH2 domain mutant, we demonstrate that the SLP-76 SH2 domain is required for peripheral T cell activation and positive selection of thymocytes, a function not previously attributed to this region. This domain is also important for T cell proliferation, IL-2 production, and phosphorylation of protein kinase D and IκB. ADAP-deficient T cells display similar, but in some cases less severe, defects despite phosphorylation of a negative regulatory site on SLP-76 by HPK1, a function that is lost in SLP-76 SH2 domain mutant T cells.     

Microbial fuel cells demonstrate high coulombic efficiency applicable for water remediation

Microbial fuel cells (MFCs) convert biomass into electricity by the metabolic activity of microorganisms and are also used for remediation and water treatment. Power output was compared for a dual chambered membrane MFC using either E. coli or two Yamuna river samples, Yamuna (before the Sangam region)--slow flow (sample 1) and Sangam region--fast flow (sample 2). E. coli and the two river water samples 1 and 2 gave a maximum voltage of 779, 463 and 415 mV respectively. Using E. coli the maximum power density obtained with a 100 omega resistor was 220.66 mW/cm2 and the highest power generated 6068.41 mW. The results demonstrate E. coli, river sample 1 and river sample 2 have a comparable coulombic efficiency of 85.2, 71 and 77% respectively when using 0.4% sucrose as substrate. The decrease in chemical oxidative demand of all river water samples using MFC technology demonstrates efficient remediation of inland water.     

A Comparative Study of Clinical Presentation and Risk Factors for Adverse Outcome in Patients Hospitalised with Acute Respiratory Disease Due to MERS Coronavirus or Other Causes

Middle East Respiratory syndrome (MERS) first emerged in Saudi Arabia in 2012 and remains a global health concern. The objective of this study was to compare the clinical features and risk factors for adverse outcome in patients with RT-PCR confirmed MERS and in those with acute respiratory disease who were MERS-CoV negative, presenting to the King Fahad Medical City (KFMC) in Riyadh between October 2012 and May 2014. The demographics, clinical and laboratory characteristics and clinical outcomes of patients with RT-PCR confirmed MERS-CoV infection was compared with those testing negative MERS-CoV PCR. Health care workers (HCW) with MERS were compared with MERS patients who were not health care workers. One hundred and fifty nine patients were eligible for inclusion. Forty eight tested positive for MERS CoV, 44 (92%) being hospital acquired infections and 23 were HCW. There were 111 MERS-CoV negative patients with acute respiratory illnesses included in this study as “negative controls”. Patient with confirmed MERS-CoV infection were not clinically distinguishable from those with negative MERS-CoV RT-PCR results although diarrhoea was commoner in MERS patients. A high level of suspicion in initiating laboratory tests for MERS-CoV is therefore indicated. Variables associated with adverse outcome were older age and diabetes as a co-morbid illness. Interestingly, co-morbid illnesses other than diabetes were not significantly associated with poor outcome. Health care workers with MERS had a markedly better clinical outcome compared to non HCW MERS patients.     

Nitrogen and phosphorus budgets for a tropical watershed impacted by agricultural land use: Guayas, Ecuador

Large-scale changes in land use are occurring in many tropical regions, with significant impacts on nitrogen and phosphorus biogeochemistry. In this study we examine the relationships between land use, anthropogenic nutrient inputs, and riverine nutrient exports in a major agricultural watershed of the Pacific coast of South America, the Guayas River basin of Ecuador. We present comprehensive nutrient budgets for nitrogen (N) and phosphorous (P) for the Guayas River basin and 10 sub-watersheds. We quantify the four major anthropogenic nutrient fluxes into and out of the region: N and P fertilizer application, N fixation by leguminous crops, net import/export of N and P in agricultural products (food and feed), and atmospheric deposition. We also estimate inputs of N from biological N fixation in forests and of P from weathering sources in soils and bedrock. The sum of these sources represents net inputs of N and P to each watershed region. Overall, synthetic fertilizers are the largest input to the Guayas Basin for N (53%) and P (57%), and the largest outputs are N and P in crops. Losses of N and P in river export account for 14–38% of total N and P inputs, and there is significant accumulation of N and P, or unmeasured forms of N and P export, in most of the sub-basins. Nutrient balances are indicative of the sustainability of land use practices in a region, where a negative balance of N or P indicates nutrient depletion and subsequent loss of soil fertility, yield, and economic viability. Although the nutrient balance of the entire Guayas Basin is positive, there are negative or near zero balances in two sub-watersheds with extensive banana, coffee and permanent crops. In these basins, degradation of soil quality may be occurring due to these net nutrient losses. Our data show that nutrients are leaving the basin primarily as export crops, with riverine losses of nutrients smaller than crop exports. Nonetheless, there is a direct relationship between nutrient inputs and river outputs, suggesting that agricultural management practices in the basin may have direct impacts on N and P delivery to the highly productive Guayas estuary.