Nisin production in a chitin-including continuous fermentation system with Lactococcus lactis displaying a cell wall chitin-binding domain

The limiting factors in the continuous production of nisin are high amount of biomass loss and low dilution rate application. In this study, a chitin-including continuous nisin fermentation system (CICON-FER) was constructed for high volumetric nisin production using nisin producer L. lactis displaying cell wall chitin-binding domain (ChBD) together with chitin in the reactor. In this respect, the highest binding conditions of relevant L. lactis cells to chitin were determined. Then the chitin flakes carrying nisin-producing L. lactis cells were used within the CICON-FER system at different dilution rates (0.1–0.9 h^?1) and initial glucose concentrations (20–60 g l^?1). The results revealed that the pH 7 conditions and the use of 100 mM sodium phosphate buffer with 0.1 % Tween 20 and Triton X-100 significantly increased the binding capacity of ChBD displaying L. lactis cells to chitin. The constructed CICON-FER system maintained the presence of the ChBD surface displaying L. lactis cells in the reactor system until 0.9 h^?1 dilution rate that resulted in a considerably high level of volumetric nisin production and productivity (10,500 IU ml^?1 and 9,450 IU ml^?1 h^?1, respectively) with the combination of a 0.9-h^?1 dilution rate and a 40-g l^?1 initial glucose concentration. In conclusion, an innovative nisin fermentation system that yielded the highest nisin production thus far and that was feasible for industrial application was created.     

The first study on bacterial flora of pest beetles Sciaphobus squalidus,Tatianaerhynchites aequatus and Byctiscus betulae in the Republic of Moldova

The present study was conducted to identify the microbial flora of pest weevils Sciaphobus squalidus (Gyll.), Tatianaerhynchites aequatus (L.) and Byctiscus betulae L., which may provide novel approaches for insect biocontrol. According to morphological, physiological, biochemical and molecular properties thirteen bacteria were revealed and characterized. Ten of these bacteria were identified at the species level and the rest at the genus level. Isolates were identified as Staphyloccocus haemolyticus (Ta5), Bacillus cereus (Ss1), Pseudomonas moraviensis (Ss4), Pseudomonas fluorescens (Ss2), Pantoea agglomerans (Ss3, Bb3), Klebsiella pneumoniae (Ta1, Ta3, and Ta4), Erwinia billingiae (Ta2) and Erwinia spp. (Bb1, Bb2, Bb4). This is the first record of bacterial isolates (Ss4, Ta2 and Ta5) from any insect. The pathogenicity of bacteria was tested against adults of S. squalidus, T. aequatus and B. betulae and three of them showed insecticidal activity. The highest activity, 93% had B. cereus on S. squalidus and 90% on B. betulae within five days. The maximum activities of other two isolates Ss2 and Ss4 were determined as 73% and 46% against S. squalidus. Our data can offer useful information for future investigations on bacterial agent development and implementation as insecticides in agricultural system.     

J deflections on ECG in severe hypothermia and hypokalaemia: a case report

The J wave, also known as Osborn wave, is a deflection that can be observed on the surface ECG as a late delta wave, seen at the end of the QRS complex. In this case, a 75-year-old woman, after 1 day of continuous haemodialysis, showed a marked hypothermia (28.5°C) and severe hypokalaemia (1.7 mEq/l). Bradycardia was seen on the monitor and J waves were recognised on the ECG recording. After appropriate replacement of potassium and treatment of hypothermia, the J waves disappeared spontaneously.     

An electrophysiological study of the sequential water swallowing

BackgroundSequential water swallowing (SWS) was mostly investigated by the videofluoroscopic and endoscopic methods. However some physiological features of SWS was rarely evaluated by neurophysiological techniques. Our aim was to investigate some neural and muscular changes on sequences of SWS using electromyography (EMG) methods.MethodsFifty-eight normal adults were investigated. SWS was initiated voluntarily with 50 ml and 100 ml water volumes from a cup. Submental EMG, respiratory signals, heart rate, and sympathetic skin responses (SSR) were measured during SWS.Key resultsAll parameters were increased significantly during the 100 ml SWS. During swallowing apnea period, compensatory respiration cycles occurred in 24% and 48% of participants in the 50 ml and 100 ml SWS, respectively. Heart rate increased during swallowing apnea. SSR were evoked just before and just after the SWS in more than halves of participants. A foreburst EMG in SM muscles at the initiation of SWS was recorded in 86% of normal participants. Older age was associated with a prolonged duration of the apnea period.ConclusionsAll parameters of the SWS could be recorded numerically and objectively using electrphysiological methods. These are similar to those obtained by videofluoroscopic and similar methods. The foreburst activity of the initiation of SWS may represents preparatory activity from the activation of the fast cortical descending motor pathway. Increasing heart rate and the prolonged apnea urged that older people and patients could be carefully tested for respiratory and cardiac rhythm disorders.     

Non-Ionic Contrast Media Induces Oxidative Stress and Apoptosis Through Ca2+ Influx in Human Neutrophils

Non-ionic contrast media (CM) can induce tissue kidney injury via activation of phagocytosis and oxidative stress, although the mechanisms of injury via neutrophils are not clear. We investigated the effects of CM on oxidative stress and Ca²⁺ concentrations in serum and neutrophils of humans. Ten migraine patients were used in the study. Serum and neutrophil samples from patients?? peripheral blood were obtained before (control) and 30?min after non-ionic (iopromide) CM injection. The neutrophils were incubated with non specific transient receptor potential 2 (TRPM2) channel blocker, 2-aminoethoxydiphenyl borate (2-APB), and voltage gated Ca²⁺ channel blockers, verapamil plus diltiazem. Serum and neutrophil lipid peroxidation, apoptosis and intracellular Ca²⁺ concentrations levels were higher in the CM group than in controls. The neutrophilic reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) levels as well as serum vitamin E and ??-carotene concentrations were lower in the CM group than in controls. Neutrophil lipid peroxidation levels were lower in the CM+2-APB and CM+verapamil-diltiazem groups than in the CM group, although GSH, GSH-Px and intracellular Ca²⁺ values increased in the CM+2-APB and CM+verapamil-diltiazem groups. However, caspase-3, caspase-9, vitamin A and vitamin C values were unaltered by CM treatment. In conclusion, we observed that CM induced oxidative stress and Ca²⁺ influx by decreasing vitamin E, ??-carotene and Ca²⁺ release levels in human serum and neutrophils. However, we observed protective effects of Ca²⁺ channel blockers on Ca²⁺ influx in neutrophils.     

Robustness of Massively Parallel Sequencing Platforms

The improvements in high throughput sequencing technologies (HTS) made clinical sequencing projects such as ClinSeq and Genomics England feasible. Although there are significant improvements in accuracy and reproducibility of HTS based analyses, the usability of these types of data for diagnostic and prognostic applications necessitates a near perfect data generation. To assess the usability of a widely used HTS platform for accurate and reproducible clinical applications in terms of robustness, we generated whole genome shotgun (WGS) sequence data from the genomes of two human individuals in two different genome sequencing centers. After analyzing the data to characterize SNPs and indels using the same tools (BWA, SAMtools, and GATK), we observed significant number of discrepancies in the call sets. As expected, the most of the disagreements between the call sets were found within genomic regions containing common repeats and segmental duplications, albeit only a small fraction of the discordant variants were within the exons and other functionally relevant regions such as promoters. We conclude that although HTS platforms are sufficiently powerful for providing data for first-pass clinical tests, the variant predictions still need to be confirmed using orthogonal methods before using in clinical applications.