The effect of carbon sources on the expression level of thermostable L2 lipase in Pichia pastoris

Thermostable lipases are enzymes that are particularly pleasing for industrial purposes such as in the production of detergents, animal skin-based industry and food processing endeavours. Thermostable L2 lipase gene fished out from Bacillus sp. L2 was cloned into Pichia pastoris strain GS115 under constitutive expression system of pGAPZαA. Study performed on various carbon sources revealed that glucose and glycerol support the growth of Pichia pastoris and expression of L2 lipase. In addition, the by-product of sugar refinery processes (molasses) was found to be a potential carbon source for the growth of P. pastoris and L2 lipase expression. Since the thermostable L2 lipase will be extracellularly secreted into the medium, the use of P. pastoris expression system is seen as an alternative to the conventional expression system of Escherichia coli that applies intracellular expression of the L2 lipase gene encoded.Key words: Thermostable lipase, Pichia pastoris, constitutive expression, carbon source

Microarray analysis revealed different gene expression patterns in HepG2 cells treated with low and high concentrations of the extracts of Anacardium occidentale shoots

In this study, the effects of low and high concentrations of the Anacardium occidentale shoot extracts on gene expression in liver HepG2 cells were investigated. From MTT assays, the concentration of the shoot extracts that maintained 50% cell viability (IC50) was 1.7 mg/ml. Cell viability was kept above 90% at both 0.4 mg/ml and 0.6 mg/ml of the extracts. The three concentrations were subsequently used for the gene expression analysis using Affymetrix Human Genome 1.0 S.T arrays. The microarray data were validated using real-time qRT–PCR. A total of 246, 696 and 4503 genes were significantly regulated (P < 0.01) by at least 1.5-fold in response to 0.4, 0.6 and 1.7 mg/ml of the extracts, respectively. Mutually regulated genes in response to the three concentrations included CDKN3, LOC100289612, DHFR, VRK1, CDC6, AURKB and GABRE. Genes like CYP24A1, BRCA1, AURKA, CDC2, CDK2, CDK4 and INSR were significantly regulated at 0.6 mg/ml and 1.7 mg but not at 0.4 mg/ml. However, the expression of genes including LGR5, IGFBP3, RB1, IDE, LDLR, MTTP, APOB, MTIX, SOD2 and SOD3 were exclusively regulated at the IC50 concentration. In conclusion, low concentrations of the extracts were able to significantly regulate a sizable number of genes. The type of genes that were expressed was highly dependent on the concentration of the extracts used

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Využití tixoformingu jako metody výroby kovových kompozitů

Tixoforming patří do skupiny procesů využívající semi-solid zpracování. Touto metodou je možné získat díly s komplexním tvarem a díky svým tixotropním vlastnostem lze dosáhnout nekonvenčních mikrostruktur. V této studii však byl tixoforming použit jak jako způsob tváření, tak i způsob výroby. Kovové kompozity byly vyrobeny procesem integrace práškové metalurgie a techniky výroby polotuhých látek. Směs slitiny Co72.5B15Si12.5 a Fe se částečně roztaví, mechanicky stlačí v polotuhém stavu a vyplní tvarovou dutiny formy. Bez změny struktury slitiny by bylo možné jí zpevnit využitím prášku Fe. Kromě toho bylo možno současně dosáhnout i konečného tvaru produktu. Před procesem byla slitina Co72.5B15Si12.5 ve formě tyčinky charakterizována rentgenovou difrakcí (XRD), skenovací elektronovou mikroskopií - energetickou disperzní spektroskopií (SEM – EDX), diferenční termickou analýzou - termogravimetrií (DTA-TG) ), světelnou mikroskopií a měřením mikrotvrdosti. Tyčinka byla namleta, aby byl získán prášek, který byl následně smíchán s práškem Fe. Po tváření byla provedena charakterizace struktur kompozitního materiálu. Bylo zjištěno, že proces zpracování vede k získání kompletních kompozitů s kovovou matricí.Thixoforming is one of the members of the family of semi-solid forming processes. It is possible to obtain complex shape of materials by this method and unconventional microstructures can be achieved due to its thixotropic properties. However, in this study thixoforming was used not only as forming method but also as a manufacturing method. Metallic composites were manufactured by a process of integration of powder metallurgy and semi-solid production technique. The mixture of Co72.5B15Si12.5 alloy and Fe powders become partially melted, compressed mechanically in semi-solid state and filled intricate cavities. Without changing alloy structure, it could be possible to reinforce it with Fe powders. Moreover, the final shape of the product could be achieved at the same time. Prior to the process, Co72.5B15Si12.5 alloy obtained in the form of stick was characterized by X-ray diffraction (XRD), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDX), differential thermal analysis-thermogravimetry (DTA-TG), light microscope and micro-hardness machine. The stick was milled to get alloy powders and they were blended with iron. Characterization of the structures of the composite material was performed. It was concluded that the heating process of iron and alloy powders provides the formation of compact metal matrix composites