(-)-glaciantarcin, a new dipeptide and some secondary metabolites from the psychrophilic yeast Glaciozyma antarctica PI12

A new dipeptide, (-)-glaciantarcin (1) and three known compounds, cyclo(-Pro-Gly) (2), 1-(2-deoxypentofuranosyl)-5-methyl-2,4(1H,3H)-pyrimidinedione (3) and vidarabine (Ara-A) (4), were isolated from Glaciozyma antarctica PI12, a cold-adapted yeast. The chemical structures were elucidated by FT-IR, NMR and mass spectrometry. The cytotoxicity and antioxidant activities of compounds 1-4 were evaluated by using the MTT bioassay on MCF-7 (human breast cancer cell line), PC-3 (human prostate cancer cell line) and HEK-293 (normal human embryonic kidney cell line) and DPPH free radical scavenging activity, respectively. At concentration of 400 μM, all compounds showed the highest activity on MCF-7, with compound 1 at 65%, compound 2 (70%), compound 3 (66%) and compound 4 (58%) cell viability. All compounds exhibited weak antioxidant properties. To the best of our knowledge, this is the first report of compounds 1-4 from Glaciozyma antactica

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

An effective extracellular protein secretion by an ABC transporter system in Escherichia coli: statistical modeling and optimization of cyclodextrin glucanotransferase secretory production

Direct transport of recombinant protein from cytosol to extracellular medium offers great advantages, such as high specific activity and a simple purification step. This work presents an investigation on the potential of an ABC (ATP-binding cassette) transporter system, the hemolysin transport system, for efficient protein secretion in Escherichia coli (E. coli). A higher secretory production of recombinant cyclodextrin glucanotransferase (CGTase) was achieved by a new plasmid design and subsequently by optimization of culture conditions via central composite design. An improvement of at least fourfold extracellular recombinant CGTase was obtained using the new plasmid design. The optimization process consisted of 20 experiments involving six star points and six replicates at the central point. The predicted optimum culture conditions for maximum recombinant CGTase secretion were found to be 25.76 µM IPTG, 1.0% (w/v) arabinose and 34.7°C post-induction temperature, with a predicted extracellular CGTase activity of 68.76 U/ml. Validation of the model gave an extracellular CGTase activity of 69.15 ± 0.71 U/ml, resulting in a 3.45-fold increase compared to the initial conditions. This corresponded to an extracellular CGTase yield of about 0.58 mg/l. We showed that a synergistic balance of transported protein and secretory pathway is important for efficient protein transport. In addition, we also demonstrated the first successful removal of the C-terminal secretion signal from the transported fusion protein by thrombin proteolytic cleavage

Fermentative production of xylitol: a first trial on xylose bifurcation

Xylitol production through chemical processes pathway involves high energy usage and production cost. Alternative method via microbial biotransformation and biocatalyst offer more sustainable and environmental friendly feedstock to be used for xylitol production. Methods: Production of xylitol by Aspergillus niger PY11 using different conditions on 2 carbon source, glucose and xylose, were done for the development of this research. Batch fermentation of A. niger PY11 was conducted for 4 days or 96 hours in temperature set at 30°C and agitation speed of 200 rpm. Samples were taken at 12 hours interval, filtered and analyzed for cell biomass, remaining sugar and D-xylitol concentration. The production of biomass and xylitol was monitored through dry-mass weight of mycelium and by HPLC, respectively. Findings: From the results of the utilization of single carbon source, fermentation of D-xylose produced the highest xylitol yield, which was 0.101 g xylitol/g D-xylose consumed, with the xylitol titre of 1.139 g/l was obtained (equivalent to 0.482 g xylitol/g biomass). However, the highest cell growth was observed when fermentation were conducted using a mixture of D-xylose and D-glucose at the ratio of 3:1, which resulted the biomass yield of 0.239 g biomass/g D-xylose (equivalent to 0.211 g xylitol/g biomass). Total amount of 44.94% of added D-xylose was consumed during the fermentation. Applications/Improvements: This paper shown that the addition of glucose had resulted higher biomass growth of A.nigerPY11, thus subsequently increased the bioconversion of xylose to xylitol

Expression of xylanase on Escherichia coli using a truncated ice nucleation protein of Erwinia ananas (InaA)

Cell surface display involves the anchoring of enzymes on the surface of cells to be used as whole-cell biocatalysts. In this study, an ice nucleation protein (INP) anchor from Erwinia ananas IN-10, InaA, was used to display xylanase. The ability of InaA to be targeted to the outer membrane was compared to cells displaying xylanase using two other INPs, InaK and InaZ. SDS-PAGE and western blot of the outer membrane fraction proved that surface targeting was successful. Whole-cell xylanase activity showed that InaA anchored xylanase gave an activity of 92.2 U/g dry cell weight which was up to three times higher than the other two display constructs used. Surface anchoring of InaA was up to four times better compared to the other two INP anchors as was confirmed by flow cytometry. Expression of InaA on the surface was optimized by one-factor-at-a-time (OFAT) to obtain the optimum parameter conditions for highest surface expression. The results presented showed that InaA is an excellent INP for surface display for xylanase and has great potential in the degradation of xylan

Bioconversion of pineapple pomace for xylooligosaccharide synthesis using surface display of xylanase on Escherichia coli

Cell surface display of xylanase on Escherichia coli was used for the hydrolysis of hemicellulose from pineapple pomace. The feasibility of bioconversion of lignocellulosic biomass into xylooligosaccharides (XOS) was investigated. In this study, pineapple pomace was pretreated, and the hemicellulose fraction was obtained for reaction with the whole-cell biocatalyst. FESEM and FTIR analyses were used to observe morphological and compositional changes of pineapple pomace respectively after pretreatment. Factors affecting hydrolysis reaction were investigated and optimized using the Box-Behnken Design. The highest amount of reducing sugar was produced at pH 7.5, cell loading of 100 g/L wet cell weight, and temperature of 30 °C. The amount of reducing sugar produced was 2.129 mg/ml. HPLC analysis indicated that the XOS produced were xylobiose and xylotriose with a total yield of 5.4 mg/g of pineapple hemicellulose. FESEM analysis on the surface structure of pineapple pomace after the hydrolysis reaction showed clear signs of degradation by xylanase. Based on the results presented, it can be deduced that the application of cell surface display on E. coli for degradation of lignocellulosic biomass is possible and should be explored as it offers great potential for the production of XOS in industry.

Review Update on the Life Cycle, Plant–Microbe Interaction, Genomics, Detection and Control Strategies of the Oil Palm Pathogen Ganoderma boninense

Plant pathogens are key threats to agriculture and global food security, causing various crop diseases that lead to massive economic losses. Palm oil is a commodity export of economic importance in Southeast Asia, especially in Malaysia and Indonesia. However, the sustainability of oil palm plantations and production is threatened by basal stem rot (BSR), a devastating disease predominantly caused by the fungus Ganoderma boninense Pat. In Malaysia, infected trees have been reported in nearly 60% of plantation areas, and economic losses are estimated to reach up to ~USD500 million a year. This review covers the current knowledge of the mechanisms utilized by G. boninense during infection and the methods used in the disease management to reduce BSR, including cultural practices, chemical treatments and antagonistic microorganism manipulations. Newer developments arising from multi-omics technologies such as whole-genome sequencing (WGS) and RNA sequencing (RNA-Seq) are also reviewed. Future directions are proposed to increase the understanding of G. boninense invasion mechanisms against oil palm. It is hoped that this review can contribute towards an improved disease management and a sustainable oil palm production in this region

Development and validation of a medium for recombinant endo-β-1,4- xylanase production by kluyveromyces lactis using a statistical experimental design

Kluyveromyces lactis is an excellent host for a high cell density culture, which allows high expression levels of recombinant enzymes. Nutrient composition and culture conditions affect the secretion, production level and stability of the recombinant host. Therefore, it is technologically important to formulate a medium that stimulates high cell density and enhances the desired enzyme production using K. lactis GG799. In this study, six media were initially compared, and a Plackett-Burman experimental design was employed to screen for important components and trace elements. Nitrogen sources such as ammonium sulfate and free amino acid (casamino acid) as well as compounds like MgSO4∙7H2O, Na2SO4, ZnSO4∙6H2O, MnSO4∙4H2O and KH2PO4 affected biomass concentrations (5.67 g/l) and recombinant endo-β-1,4-xylanase (Xyn2) production (49.73 U/ml). Optimum productivity was obtained at shorter incubation times (i.e., 6 h), making the medium suitable for use when seeking efficient production. Expression of recombinant Xyn2 by K. lactis GG799 in the designed medium resulted in satisfactory recombinant Xyn2 volumetric productivity (vp) at 8.29 U/ml/h. When compared to the rich, non-selective YPD medium, the designed medium improved biomass output and recombinant Xyn2 production in K. lactis GG799 by approximately 9 and 22%, respectively

Development and validation of a medium for recombinant endo-ß-1,4-xylanase production by Kluyveromyces lactis using a statistical experimental design

Kluyveromyces lactis is an excellent host for a high cell density culture, which allows high expression levels of recombinant enzymes. Nutrient composition and culture conditions affect the secretion, production level and stability of the recombinant host. Therefore, it is technologically important to formulate a medium that stimulates high cell density and enhances the desired enzyme production using K. lactis GG799. In this study, six media were initially compared, and a Plackett-Burman experimental design was employed to screen for important components and trace elements. Nitrogen sources such as ammonium sulfate and free amino acid (casamino acid) as well as compounds like MgSO4·7H2O, Na2SO4, ZnSO4·6H2O, MnSO4·4H2O and KH2PO4 affected biomass concentrations (5.67 g/l) and recombinant endo-ß-1,4-xylanase (Xyn2) production (49.73 U/ml). Optimum productivity was obtained at shorter incubation times (i.e., 6 h), making the medium suitable for use when seeking efficient production. Expression of recombinant Xyn2 by K. lactis GG799 in the designed medium resulted in satisfactory recombinant Xyn2 volumetric productivity (vp) at 8.29 U/ml/h. When compared to the rich, non-selective YPD medium, the designed medium improved biomass output and recombinant Xyn2 production in K. lactis GG799 by approximately 9 and 22%, respectively