286 research outputs found
Investigating sources and sinks of N2O expression from freshwater microbial communities in urban watershed sediments
Wastewater treatment plants (WWTPs) serve as point-source inputs for a variety of nutrients often dominated by nitrogenous compounds as a result of anthropogenic influence. These effluents can impact biogeochemical cycles in freshwater estuaries, influencing microbial communities in both the water and sediment compartments. To assess the impact of point source nutrients, a transect of sediment and pore water samples were collected from 4 locations in the Little River Sub-watershed including locations above and below the Little River Pollution Control Plant (LRPCP). Variation in chemistry and microbial community/gene expression revealed significant influences of the effluent discharge on the adjacent sediments. Phosphorus and sulfur showed high concentrations within plume sediments compared to the reference sediments while nitrate concentrations were low. Increased abundance of denitrifiers Dechloromonas, Dok59 and Thermomonas correlating with increased expression of nitrous-oxide reductase suggests a conversion of N2O to N2 within the LRPCP effluent sediments. This study provides valuable insight into the gene regulation of microbes involved in N metabolism (denitrification, nitrification, and nitrite reduction to ammonia) within the sediment compartment influenced by wastewater effluent. © 2017 Elsevier Lt
Attenuation and modification of the ballast water microbial community during voyages into the Canadian Arctic
Aim: Ballast water is a major vector of non-indigenous species introductions world-wide. Our understanding of population dynamics of organisms entrained in ballast is largely limited to studies of zooplankton and phytoplankton. Bacteria are more numerous and diverse than zooplankton or phytoplankton, yet remain comparatively understudied. We apply a metagenomics approach to characterize changes in the microbial ballast water community over the course of three voyages on one ship, and assess the effects of ballast water exchange (BWE), spring/summer sampling month and time since voyage start. Location: Quebec City and Deception Bay, Quebec, and the coastal marine region offshore of eastern Canada. Methods: We used universal primers to Ion Torrent sequence a fragment of the bacterial 16S ribosomal DNA for samples collected over three voyages of one ship between Quebec City and Deception Bay in June, July and August 2015. We compared richness (total number of species in the community) and diversity (accounts for both species abundance and evenness) using linear mixed-effects analysis and compared community composition using non-metric multidimensional scaling and permutational multivariate analysis of variance. Initial comparisons were between months. Subsequent analyses focused on each month separately. Results: Ion Torrent sequencing returned c. 2.9 million reads and revealed monthly differences in diversity and richness, and in community structure in ballast water. June had higher richness and diversity than either July or August, and showed most clearly the effect of BWE on the microbial community. Main conclusions: Our results suggest that environmental conditions associated with different spring/summer sampling months drive differences in microbial diversity in ballast water. This study showed that BWE removes some components of the freshwater starting microbial community and replaces them with other taxa. BWE also changed proportional representation of some microbes without removing them completely. It appears that some taxa are resident in ballast tanks and are not removed by BWE. © 2017 John Wiley & Sons Lt
The role of competencies in shaping the leadership style of female entrepreneurs: the case of North West of England, Yorkshire, and North Wales
This study investigates linkages between personal competencies and leadership style among female small and micro business owners. Although prior research suggests that leadership style is shaped according to a leader's traits and abilities, few empirical studies corroborate this, particularly among female owners. Using survey data from the North West of England, Yorkshire, and North Wales, we reveal that transformational leadership style is the most dominant style adopted, and it is linked to perceived human and personal competencies as well as entrepreneurial competencies
Insilico and Invitro anthelmintic properties of phytocompounds in Rostellularia quinquangularis (J. Koenig ex Roxb.) Nees
The present study aimed to evaluate the anthelmintic activity of various extracts of Rostellularia quinquangularis (R. quinquangularis) against adult Indian earthworms (Pheretima posthuma). Petroleum ether extract (PERQ), ethyl acetate extract (RQEA), and ethanol extract (RQEE) of R. quinquangularis were tested at different concentrations (10, 20, 50, and 100 mg/mL), along with the positive control (albendazole) and negative control (normal saline). Anthelmintic activity was assessed based on the duration of paralysis and mortality. The RQEE extract showed significant anthelmintic activity, with the highest activity observed at a concentration of 100 mg/mL, exhibiting paralysis time of 1.62 min and death times of 19.9 min, compared to the standard albendazole. Further, HR LC-MS analysis of the RQEE extract revealed the presence of various phytoconstituents based on m/z signals. Molecular docking analysis using AutoDock Vina indicated that Columbianetin, Dunnione, Cryptochlorogenic acid, Gaylussacin, Luvangetin, and Albendazole showed docking scores of -8.1, -7.9, -7.4, -7.3, -7.2, and -6.8 Kcal/mol, respectively. These results suggest that R. quinquangularis possesses potent anthelmintic activity, supporting its traditional use in medicinal practices.
Economic liberalization and the antecedents of top management teams: evidence from Turkish 'big' business
There has been an increased interest in the last two decades in top management teams (TMTs) of business firms. Much of the research, however, has been US-based and concerned primarily with TMT effects on organizational outcomes. The present study aims to expand this literature by examining the antecedents of top team composition in the context of macro-level economic change in a late-industrializing country. The post-1980 trade and market reforms in Turkey provided the empirical setting. Drawing upon the literatures on TMT and chief executive characteristics together with punctuated equilibrium models of change and institutional theory, the article develops the argument that which firm-level factors affect which attributes of TMT formations varies across the early and late stages of economic liberalization. Results of the empirical investigation of 71 of the largest industrial firms in Turkey broadly supported the hypotheses derived from this premise. In the early stages of economic liberalization the average age and average organizational tenure of TMTs were related to the export orientation of firms, whereas in later stages, firm performance became a major predictor of these team attributes. Educational background characteristics of teams appeared to be under stronger institutional pressures, altering in different ways in the face of macro-level change
Rmi1 stimulates decatenation of double Holliday junctions during dissolution by Sgs1-Top3
double Holliday junction (dHJ) is a central intermediate of homologous recombination that can be processed to yield crossover or non-crossover recombination products. To preserve genomic integrity, cells possess mechanisms to avoid crossing over. We show that Saccharomyces cerevisiae Sgs1 and Top3 proteins are sufficient to migrate and disentangle a dHJ to produce exclusively non-crossover recombination products, in a reaction termed "dissolution." We show that Rmi1 stimulates dHJ dissolution at low Sgs1-Top3 protein concentrations, although it has no effect on the initial rate of Holliday junction (HJ) migration. Rmi1 serves to stimulate DNA decatenation, removing the last linkages between the repaired and template DNA molecules. Dissolution of a dHJ is a highly efficient and concerted alternative to nucleolytic resolution that prevents crossing over of chromosomes during recombinational DNA repair in mitotic cells and thereby contributes to genomic integrity
Role of Personal Networks in the Growth of Entrepreneurship Ventures of Ethnic Minority Female Entrepreneurs
The main objective of the paper is to explore and explain the differences/similarities in personal networks of, and their use by, immigrant and British born Pakistani female entrepreneurs for business growth.A broad range of studies has explored the social context of ethnic minority and immigrant entrepreneurship by assuming all minority entrepreneurs as a cohesive group without taking into account intergroup (geographical categorisation) and intra-group (generational) differences. These differences are explained by socio-economic and cultural factors such as family background and support, ethnicity, religion, education, and more importantly personal network (Metcalf et. al., 1996; Basu, 1998). The blend of culture and religion depicted in entrepreneurial practices of Pakistani entrepreneurs is an interesting but under-researched area. Our particular interest is to explore the scope, depth, variations and limitations of the personal networks of Pakistani female entrepreneurs in their effort to grow their business
Chromosomal imbalances associated with carcinoma in situ and associated testicular germ cell tumours of adolescents and adults
Carcinoma in situ (CIS) or intratubular germ cell neoplasia is generally considered the precursor lesion of adult testicular germ cell tumours (TGCT). The chromosomal imbalances associated with CIS and the corresponding seminoma (SE) or nonseminoma (NS) have been determined by comparative genomic hybridization (CGH) analysis of microdissected material from seven cases. Significantly, the CIS showed no gain of 12p material whereas in the invasive components of all cases gain of 12p was found, in 2 cases associated with amplification of the 12p11.2–12.1 region. Interphase fluorescence in situ analysis was consistent with this and provided evidence for the i(12p) or 12p11.2–12.1 amplification in the SE and NS but not in the corresponding CIS. This suggests a role for these changes in progression of CIS to invasive testicular cancer or progression of the invasive disease. Other imbalances such as gain of material from chromosomes 1, 5, 7, 8, 12q and X and loss of material from chromosome 18 were frequently identified (> 40% of cases) in the CIS associated with both SE and NS as well as in the invasive components. Loss of material from chromosome 4 and 13 and gain of 2p were more frequently found in the invasive components. The results shed light on the genetic relationship between the non-invasive and invasive components of testicular cancer and the stage at which particular chromosomal changes may be important. © 2001 Cancer Research Campaign http://www.bjcancer.co
Formation of Complex and Unstable Chromosomal Translocations in Yeast
Genome instability, associated with chromosome breakage syndromes and most human
cancers, is still poorly understood. In the yeast Saccharomyces
cerevisiae, numerous genes with roles in the preservation of genome
integrity have been identified. DNA-damage-checkpoint-deficient yeast cells that
lack Sgs1, a RecQ-like DNA helicase related to the human
Bloom's-syndrome-associated helicase BLM, show an increased rate of
genome instability, and we have previously shown that they accumulate recurring
chromosomal translocations between three similar genes, CAN1,
LYP1 and ALP1. Here, the chromosomal
location, copy number and sequence similarity of the translocation targets
ALP1 and LYP1 were altered to gain insight
into the formation of complex translocations. Among 844 clones with chromosomal
rearrangements, 93 with various types of simple and complex translocations
involving CAN1, LYP1 and ALP1
were identified. Breakpoint sequencing and mapping showed that the formation of
complex translocation types is strictly dependent on the location of the
initiating DNA break and revealed that complex translocations arise via a
combination of interchromosomal translocation and template-switching, as well as
from unstable dicentric intermediates. Template-switching occurred between
sequences on the same chromosome, but was inhibited if the genes were
transferred to different chromosomes. Unstable dicentric translocations
continuously gave rise to clones with multiple translocations in various
combinations, reminiscent of intratumor heterogeneity in human cancers. Base
substitutions and evidence of DNA slippage near rearrangement breakpoints
revealed that translocation formation can be accompanied by point mutations, and
their presence in different translocation types within the same clone provides
evidence that some of the different translocation types are derived from each
other rather than being formed de novo. These findings provide
insight into eukaryotic genome instability, especially the formation of
translocations and the sources of intraclonal heterogeneity, both of which are
often associated with human cancers
Novel compounds with antiangiogenic and antiproliferative potency for growth control of testicular germ cell tumours
- …