Overcoming the metabolic burden of protein secretion in Schizosaccharomyces pombe – A quantitative approach using 13C-based metabolic flux analysis

Protein secretion in yeast is generally associated with a burden to cellular metabolism. To investigate this metabolic burden in Schizosaccharomyces pombe, we constructed a set of strains secreting the model protein maltase in different amounts. We quantified the influence of protein secretion on the metabolism applying ¹³C-based metabolic flux analysis in chemostat cultures. Analysis of the macromolecular biomass composition revealed an increase in cellular lipid content at elevated levels of protein secretion and we observed altered metabolic fluxes in the pentose phosphate pathway, the TCA cycle, and around the pyruvate node including mitochondrial NADPH supply. Supplementing acetate to glucose or glycerol minimal media was found to improve protein secretion, accompanied by an increased cellular lipid content and carbon flux through the TCA cycle as well as increased mitochondrial NADPH production. Thus, systematic metabolic analyses can assist in identifying factors limiting protein secretion and in deriving strategies to overcome these limitations.     

Differences in pacemaker programming between electrophysiology specialists and other physicians

BackgroundAppropriate programming of cardiovascular implantable electronic devices (CIED) is essential to ensure adequate function and avoid harmful effects. In underdeveloped countries, CIED monitoring and programming are often performed by physicians involved in their implantation. However, many of them often do not have sufficient training in CIED programming.ObjectiveWe aimed to assess the differences in pacemaker programming between electrophysiology (EP) specialists and other physicians.MethodsWe retrospectively reviewed changes in pacemaker programming performed by an EP specialist in patients who attended for pacemaker evaluation and reported previous follow-ups by a non-EP specialist.ResultsAmong 58 patients (26 males), 41 patients (71%) had programming errors and required setting modifications. The rate adaptative pacing function (R-mode) was incorrectly deactivated in 9 patients (15%) and improperly activated in 2 patients (3%). Unnecessary ventricular stimulation was detected in 23 patients (40%) with a pacing burden of 60% (32–95%). The lower rate limit was unnecessarily high in 12 patients (21%).Atrial or ventricular pacing output was inappropriate in 15 patients (26%) and was consequently modified (4 patients unnecessarily high, 9 patients below requirements). The auto-adapted pacing output was switched off in 17 of 18 patients (16 due to physician's preference, and 1 due to algorithm inaccuracy). The programmed sensitivity was inaccurate in 2 patients (3%). In 2 patients (3%) switching from DDDR to VVIR mode was required.ConclusionWe found a high prevalence of errors in pacemaker programming by non-EP specialists. An EP specialist should always be responsible for CIED follow-up.     

Infection of the fittest: devil facial tumour disease has greatest effect on individuals with highest reproductive output

Emerging infectious diseases rarely affect all members of a population equally and determining how individuals’ susceptibility to infection is related to other components of their fitness is critical to understanding disease impacts at a population level and for predicting evolutionary trajectories. We introduce a novel state‐space model framework to investigate survival and fecundity of Tasmanian devils (Sarcophilus harrisii) affected by a transmissible cancer, devil facial tumour disease. We show that those devils that become host to tumours have otherwise greater fitness, with higher survival and fecundity rates prior to disease‐induced death than non‐host individuals that do not become infected, although high tumour loads lead to high mortality. Our finding that individuals with the greatest reproductive value are those most affected by the cancer demonstrates the need to quantify both survival and fecundity in context of disease progression for understanding the impact of disease on wildlife populations.     

Efficient genetic approaches for improvement of plasmid based expression of recombinant protein in Escherichia coli: A review

During the past two decades, there has been an explosion of new knowledge and techniques in the field of recombinant protein expression. However, over-expression of “difficult to express proteins” with therapeutic importance continues to be a challenging task for successful commercialization of these proteins. With the emergence of the bio-similar market, enhancing the efficiencies of the production process has become a critical factor in the commercial viability of novel products. Despite the availability of numerous technological advancements, recombinant protein expression in Escherichia coli remains difficult. Therefore, addressing upstream bottlenecks in combination with genetically modified expression hosts could be a viable strategy to enhance production. Problems like poor expression, plasmid instability, protein aggregation, protein degradation, and metabolic stress associated with recombinant protein production need special consideration during bioprocess development at bioreactor level. However, a comprehensive universal strategy for attaining efficient expression in E. coli seems unrealistic and must be resolved empirically. In this review, we have discussed some common problems and their apparent solutions for plasmids based recombinant gene expression in E. coli.     

A new extant respirometric assay to estimate intrinsic growth parameters applied to study plasmid metabolic burden

Start‐up phenomena in microbial biokinetic assays are not captured by the most commonly used growth‐related equations. In this study we propose a new respirometric experimental design to estimate intrinsic growth parameters that allow us to avoid these limitations without data omission, separate mathematical treatment, or wake‐up pulses prior to the analysis. Identifiability and sensitivity analysis were performed to confirm the robustness of the new approach for obtaining unique and accurate estimates of growth kinetic parameters. The new experimental design was applied to establish the metabolic burden caused by the carriage of a pWW0 TOL plasmid in the model organism Pseudomonas putida KT2440. The metabolic burden associated was manifested as a reduction in the yield and the specific growth rate of the host, with both plasmid maintenance and the over‐expression of recombinant proteins from the plasmid contributing equally to the overall effect. Biotechnol. Bioeng. 2010;105: 141–149. © 2009 Wiley Periodicals, Inc.     

Cancer burden in four countries of the Middle East Cancer Consortium (Cyprus; Jordan; Israel; Izmir (Turkey)) with comparison to the United States surveillance; epidemiology and end results program

It is important that population-based cancer registries provide accurate and reliable data for public health purposes. These data are essential data for planning of cancer control and prevention. In this study, we examined cancer incidence rates (year 2005–2010) in four MECC registries (Cyprus, Jordan, Israel, Izmir (Turkey)) and compared with the rates in the US. The overall age-standardized incidence rates for males were highest in the US followed by Israeli Jews, Izmir (Turkey), Cyprus, Israeli Arabs, and lowest in Jordan. In women the rates of cancer of all sites were also highest in US women followed by Israeli Jews, Cyprus, Israeli Arabs, Izmir (Turkey), and lowest in Jordan. It is of interest that although site-specific cancer rates differ between the countries studied, prostate, lung and colorectal cancers are within the five most common cancers males in all countries studied. In females, breast colorectal and endometrium cancers are three of the five most common cancers in females in all countries studied. The results presented in this paper can have implications for opportunities in cancer control and prevention in these countries. Future studies on individual cancer sites with highest rates in these Countries are currently underway.     

Costes por incapacidad temporal en España derivados de la diabetes mellitus y sus complicaciones

Introduction and objectivesTo ascertain the socioeconomic impact of diabetes, it is essential to estimate overall costs, including both direct and indirect costs (premature retirements, working hours lost, or sick leaves). This study analyzed indirect costs for temporary disability (TD) due to diabetes and its complications in Spain in 2011 by assessing the related ICD-9 MC codes.Material and methodFor this purpose, the number of TD processes and their mean duration were recorded. The indirect costs associated to loss of working days were also estimated.ResultsIn 2011, diabetes and its complications were related to 2.567 TD processes, which resulted in the loss of 154.214 days. In terms of costs, this disease represented for Spanish public health administrations an expense of 3,297.095.3 €, with an estimated cost per patient and year of 141 €.ConclusionsThese data suggest an urgent need to devise plans for prevention and early diagnosis of diabetes and its complications, as well as programs to optimize the available health care resources by creating multidisciplinary teams where occupational medical services assume an important role. A decrease in absenteeism would result in benefits for diabetic patients, society overall, and companies or public institutions.     

Insertion-deletions burden in copy number polymorphisms of the Tibetan population

BACKGROUND:

Many studies have been conducted to identify either insertions-deletions (inDels) or copy number variations (CNVs) in humans, but few studies have been conducted to identify both of these forms coexisting in the same region.

AIMS AND OBJECTIVES:

To map the functionally significant sites within human genes that are likely to influence human traits and diseases.

MATERIALS AND METHODS:

In this report, we describe an inDel map in the 1051 Tibetan CNV regions obtained through CNV genotyping using Affymetrix Genome-wide single nucleotide polymorphism 6.0 chip. InDel polymorphisms in these copy number polymorphism regions were identified with a computational approach using the 2500 deoxyribonucleic acid sequences obtained from the 1000 Genome Project.

RESULTS:

The study identified a total of 95935 inDels that range from 1 bp to several bps in length which were found scattered across regulatory regions, exons and in introns of genes underlying the CNVs. A study on the distribution of inDels revealed that the majority of inDels were found in coding regions of the genome than the noncoding, while within the genes, inDels in intron regions were more followed by exonic regions and finally the regulatory regions.

CONCLUSION:

Study of inDels in CNV regions contribute to the enhanced understanding of the role played by the two variations and their collective influence on the genome. Further, a collection of these inDel genetic markers will aid in genetic mapping, further understanding of the phenotypic variability, identification of disease genes and in detecting novel CNVs.     

河南农村5岁以下儿童秋冬季急性胃肠炎疾病负担研究

目的 了解河南农村秋冬季节5岁以下儿童急性胃肠炎流行现状和疾病负担。方法 采用单纯随机整群抽样方法,抽取7个行政村的所有5岁以下儿童共513名。结果 5岁以下儿童秋冬季急性胃肠炎2周发病率为9.4%,疾病负担平均为2.7151 DALYs/千人,年龄越小疾病负担越高;0岁组最高,为6.5839 DALYs/千人。患儿例均经济负担为284.84元,其中直接经济负担为211.83元,间接经济负担为72.98元。结论 5岁以下儿童秋冬季急性胃肠炎发病率随年龄增长呈下降趋势,疾病负担主要集中于3岁以下儿童（尤其0~1岁婴幼儿）;秋冬季应积极预防病毒性急性胃肠炎,防控重点应在2岁以下儿童;早就诊早治疗,以减少住院病例,降低疾病负担。