Exploiting fatty acid metabolic pathway for production of short chain fatty acids in E. coli

Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of short chain fatty acids (SCFAs), such as such as butyric acid (C4), as they are attractive precursors to replace petroleum-based fuels and chemicals. In this study, we explored the fatty acid metabolism for production of butyric acid in E. coli with the help of three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron. We found that E. coli strain transformed with gene for TesBT and grown in presence of 8 g/L glucose produced maximum butyric acid titer at 1.46 g/L, followed by that of TesBF at 0.85 g/L and TesAT at 0.12 g/L, showing that these thioesterases were efficiently converting short chain fatty acyl-ACP into corresponding acid. The titer of butyric acid varied significantly depending upon the strain genotype and plasmid copy number. Deletion of genes involved in initiating the fatty acid degradation such as fatty acyl-CoA synthetase and acyl-CoA dehydrogenase and overexpression of FadR, which is a dual transcriptional regulator, exerts negative control over fatty acid degradation pathway, reduced up to 30% of butyric acid titer. This observation suggested that β-oxidation pathway is working synergistically with fatty acid synthesis pathway in production of butyric acid. Moreover, accelerating the fatty acid elongation cycle by overexpressing acetyl-CoA carboxyltransferase (Acc) and 3-hydroxy-acyl-ACP dehydratase (FabZ) or by deleting FabR, the transcription suppressor of elongation, did not improve the butyric acid titer, rather favored the long chain fatty acid production. Use of chemical inhibitor cerulenin, which limits the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay showed that cerulenin also inhibited the short chain specific thioesterases, though inhibitory concentration varied according to the type of thioesterase used. Further improvement in butyric acid was achieved by process optimization. Owing to the same pathway for both cell growth and butyric acid production, a balance was achieved between the two by growing the cells under nutrient and oxygen limiting condition. Keeping these factors in mind, a fed-batch cultivation strategy was devised for production of butyric acid in phosphorous and carbon limiting condition. Finally, we obtained 14.3 g/L of butyric acid and 17.5 g/L of total free fatty acid. The strategy used in this study resulted in highest reported titers of butyric acid and free fatty acids in engineered E. coli and could be used to replace the traditional chemical methods for production of butyric acid

The Impact of Corporate ESG Performance Disclosure across Australian Industries

The aims of this study are threefold. Firstly, it examines the long-term improvement in the corporate environmental, social and governance (ESG) performance. Secondly, it highlights the favourable financial implications of the higher corporate ESG performance disclosure. The third aim is to provide insight into the industrial impact on the relationship between corporate ESG performance disclosure and financial performance. This study uses a sample of all Australian publicly listed companies between 2007 and 2017 and conducts a panel regression analysis. It also performs several robustness checks to address the methodological, sample selection and endogeneity issues concerning corporate ESG performance disclosure. The findings show a tangible improvement in Australian companies\u27 corporate ESG performance disclosure, favourably associated with financial performance. However, while the corporate ESG performance disclosure appears to be linked to higher financial performance, this is not the case across different industries. The industrial impact on the association between corporate ESG performance disclosure and financial performance has several implications. Firstly, the stakeholders\u27 pressure on companies to address ESG-related concerns is substantial, enhancing corporate financial performance. Secondly, the findings indicate that corporate ESG performance disclosure does not benefit corporations in different industry sectors equally. It, therefore, requires more focus and interpretation by corporate decision-makers. Thirdly, by promoting ESG-related disclosure, managers should consider diverse stakeholders in different industries that weigh business objectives differently. The results of this study provide insights for corporate managers regarding prioritising resource allocations to ESG-related activities that could impact financial performance differently in different industry sectors. The results of this study contribute to the growing literature on the financial implications of corporate ESG performance disclosures, notably different industrial characteristics

Estimation of Hypsometric Integral and Groundwater Potential Zones of Amarja Reservoir Catchment, Karnataka, India using SRTM Data and Geospatial Tools

Hypsometric integral always play a significant role in watershed health condition. It is nothing but the total time taken in reduction of land area to its vile. Drainage network and studies of various landform features always help in the search of groundwater resources. Morphometric parameter of a drainage basin always helps to understand water use and land use of the basin. The present study aims to find out the geological stages through hypsometric integral values and groundwater potential zones using morphometric parameters to classify it into very good, good, moderate and poor zones using GIS tools. The total area of catchment is 544.76 km2, which is surrounded by Deccan traps. The catchment is further separated into 5 sub-basins on the basis of 4th order stream to get the more specific result. The SRTM (Shuttle Radar Topography Mission) data have been generated from USGS website and further analysed to identify the drainage pattern, slope, contours etc. using ArcGIS 10.0 software. The most important parameters like linear, areal and relief for groundwater investigation have been analysed. The analysis revealed that the hypsometric integral value of sub-basin IV of Amarja reservoir catchment is 0.30 which is showing the late mature stage of the basin. Apart from that, the values of sub-basins II, III and V are 0.54, 0.50 and 0.43 respectively, represent the mature stage while sub-basin I has an integral value of 0.67 which represents the young stage of the basin and it is more susceptible for erosion. Drainage pattern of the catchment could be mainly described as sub dendritic to dendritic. Drainage texture was found to vary from 0.41 to 1.16 which is an indicative of massive coarse to granular texture. An average bifurcation ratio of basin is estimated 3.51 which is an indicator of structural control over the basin. Slope values were found to be in a range from 0.71 to 5.73 degree which indicates very gentle to moderate slop

CRISPR/Cas9-mediated engineering of Escherichia coli for n-butanol production from xylose in defined medium.

Abstract Butanol production from agricultural residues is the most promising alternative for fossil fuels. To reach the economic viability of biobutanol production, both glucose and xylose should be utilized and converted into butanol. Here, we engineered a dual-operon-based synthetic pathway in the genome of E. coli MG1655 to produce n-butanol using CRISPR/Cas9 technology. Further deletion of competing pathway followed by fed-batch cultivation of the engineered strain in a bioreactor with glucose-containing complex medium yielded 5.4 g/L n-butanol along with pyruvate as major co-product, indicating a redox imbalance. To ferment xylose into butanol in redox-balanced manner, we selected SSK42, an ethanologenic E. coli strain engineered and evolved in our laboratory to produce ethanol from xylose, for integrating synthetic butanol cassette in its genome via CRISPR/Cas9 after deleting the gene responsible for endogenous ethanol production. The engineered plasmid- and marker-free strain, ASA02, produced 4.32 g/L butanol in fed-batch fermentation in completely defined AM1–xylose medium

FinTech and macroeconomics: Dataset from the US peer-to-peer lending platform

We aggregate the United States (US) state-level data with LendingClub's loan book covering the period from 2008 to 2019. LendingClub is a FinTech lending company that provides loans through a technology-driven platform. It was one of the pioneering and leading US peer-to-peer (P2P) lending platforms. Our dataset consists of over two million observations (N=2,703,430) with diverse loan, borrowers and state-specific features. We provide the description of variables, descriptive statistics, and STATA code with the full dataset. The US possesses significant cross-state variation in terms of economic and demographic characteristics while having risk-sharing policies at the federal level to protect states' creditworthiness. This unique feature of our combined database creates an ideal opportunity to explore the P2P lending market within the context of macroeconomic variables. As the dataset covers a 12-year period for all US states, it enables further cross-sectional and longitudinal analyses of the FinTech lending market

Transaxillary Transthoracic Approach to Upper Dorsal Spine Lesions: An Anatomical Corridor with Muscle Preservation

Objective: Conventional methods for anterior upper dorsal spine are not devoid of intra-operative complications due to anatomical constraints, a major blood vessel and vital organs. We analyzed the details of Trans- axillary approach without muscle cutting in tuberculosis, tumor, and traumatic lesions of T2 to T6 and upper limb causalgia.Materials and Methods: A prospective quasi-experimental study was conducted for 3 years included 30 patients presented with dorsal myelopathy due to D2 to D6 vertebral body involvement. Right and left sided approaches were utilized. Medical Research Council grading was used to assess neurological status.Results: Mean age was 32 ± 15 years, which included male 18.60% and female 12.40%. T4 vertebrae were commonly involved. Others were T5, T3 and T6 respectively. The majority of lesions were tuberculosis of the spine (n = 14), tumor (n = 8), trauma (n = 5) and causalgia of upper limb (n = 3). No intra-operative complications occurred, estimated blood was 80-100 ml and operative time was 120-160 minutes. Postoperative complications included pneumonia (n = 1), superficial wound infection (n = 3), death (n = 1). Serial follow up was for 2 years, Patients were discharged with improved neurological status and causalgia patients got immediate post-operative relief.Conclusions: Transaxillary approach is a unique anatomical corridor which is safe, feasible with promising results. It provides optimal decompression, reconstruction with better fixation and alignment in various pathologies of upper dorsal spine

Studies on the role of goat heart galectin-1 as an erythrocyte membrane perturbing agent

AbstractGalectins are β-galactoside binding lectins with a potential hemolytic role on erythrocyte membrane integrity and permeability. In the present study, goat heart galectin-1 (GHG-1) was purified and investigated for its hemolytic actions on erythrocyte membrane. When exposed to various saccharides, lactose and sucrose provided maximum protection against hemolysis, while glucose and galactose provided lesser protection against hemolysis. GHG-1 agglutinated erythrocytes were found to be significantly hemolyzed in comparison with unagglutinated erythrocytes. A concentration dependent rise in the hemolysis of trypsinized rabbit erythrocytes was observed in the presence of GHG-1. Similarly, a temperature dependent gradual increase in percent hemolysis was observed in GHG-1 agglutinated erythrocytes as compared to negligible hemolysis in unagglutinated cells. The hemolysis of GHG-1 treated erythrocytes showed a sharp rise with the increasing pH up to 7.5 which became constant till pH 9.5. The extent of erythrocyte hemolysis increased with the increase in the incubation period, with maximum hemolysis after 5h of incubation. The results of this study establish the ability of galectins as a potential hemolytic agent of erythrocyte membrane, which in turn opens an interesting avenue in the field of proteomics and glycobiology

Calcium-dependent permeabilization of erythrocytes by a perforin-like protein during egress of malaria parasites.

Clinical malaria is associated with proliferation of blood-stage parasites. During the blood stage, Plasmodium parasites invade host red blood cells, multiply, egress and reinvade uninfected red blood cells to continue the life cycle. Here we demonstrate that calcium-dependent permeabilization of host red blood cells is critical for egress of Plasmodium falciparum merozoites. Although perforin-like proteins have been predicted to mediate membrane perforation during egress, the expression, activity and mechanism of action of these proteins have not been demonstrated. Here, we show that two perforin-like proteins, perforin-like protein 1 and perforin-like protein 2, are expressed in the blood stage. Perforin-like protein 1 localizes to the red blood cell membrane and parasitophorous vacuolar membrane in mature schizonts following its Ca(2+)-dependent discharge from micronemes. Furthermore, perforin-like protein 1 shows Ca(2+)-dependent permeabilization and membranolytic activities suggesting that it may be one of the effector proteins that mediate Ca(2+)-dependent membrane perforation during egress

EXPLORATORY FACTOR ANALYSIS OF ENTREPRENEURIAL ORIENTATION IN THE CONTEXT OF BANGLADESHI SMALL AND MEDIUM ENTERPRISES (SMES)

Generally, Exploratory Factor Analysis (EFA) is required to expose the appropriate items for using in the research instrument. Thus, this study takes steps to develop and validate instrument of Entrepreneurial Orientation (EO) construct through EFA particularly in the context of Small and Medium Enterprises (SMEs) in Bangladesh. This study is exercised EFA as it is far different from previous studies in terms of socio-economic, racial and cultural status and some items of the previous studies are no longer suitable for current research. More importantly, maximum number of previous studies examined only innovativeness, pro-activeness, and risk-taking as the dimensions of EO. However, quite a few researchers concentrating on other substantial attributes of EO. Hence, there is still no common agreement among researchers as the number of dimensions as well as items should be employed to measure EO. So, this study has examined innovativeness, pro-activeness, risk-taking, and resource-leveraging as the core dimensions to measure EO and also presenting an instrument of EO. This study adopted a cross-sectional research design, while quantitative data was collected from 384 SMEs across eight states in Bangladesh, using structured survey. Based on the reliability testing, this study finalized the instrument to twelve (12) items yielding three (3) dimensions, i.e., innovativeness (3 items), pro-activeness (3 items) risk-taking (3 items), and resource-leveraging (3 items). In this regard, researchers calculated the value of internal reliability (i.e., Cronbach Alpha value) for the current EO instrument. This study explained in detail the procedures for carrying out EFA analysis for EO construct. Future researchers could further extend the instrument presented in this study by cross-examining across the underdeveloped, developing and developed countries.  Article visualizations

Biochemical, biophysical, and functional characterization of bacterially expressed and refolded receptor binding domain of Plasmodium vivax duffy-binding

Invasion of erythrocytes by malaria parasites is mediated by specific molecular interactions. Plasmodium vivax is completely dependent on interaction with the Duffy blood group antigen to invade human erythrocytes. The P. vivax Duffy-binding protein, which binds the Duffy antigen during invasion, belongs to a family of erythrocyte-binding proteins that also includesPlasmodium falciparum sialic acid binding protein andPlasmodium knowlesi Duffy binding protein. The receptor binding domains of these proteins lie in a conserved, N-terminal, cysteine-rich region, region II, found in each of these proteins. Here, we have expressed P. vivax region II (PvRII), the P. vivax Duffy binding domain, in Escherichia coli. Recombinant PvRII is incorrectly folded and accumulates in inclusion bodies. We have developed methods to refold and purify recombinant PvRII in its functional conformation. Biochemical, biophysical, and functional characterization confirms that recombinant PvRII is pure, homogeneous, and functionally active in that it binds Duffy-positive human erythrocytes with specificity. Refolded PvRII is highly immunogenic and elicits high titer antibodies that can inhibit binding of P. vivax Duffy-binding protein to erythrocytes, providing support for its development as a vaccine candidate forP. vivax malaria. Development of methods to produce functionally active recombinant PvRII is an important step for structural studies as well as vaccine development