Escherichia coli as an indicator of bacteriological quality of water: an overview

Monitoring the microbiological quality of drinking water relies largely on examination of indicator bacteria such as coliforms, <em>Escherichia coli</em>, and <em>Pseudomonas aeruginosa</em>. <em>E. coli</em> is a member of the faecal coliform group and is a more specific indicator of faecal pollution than other faecal coliforms. Two key factors have led to the trend toward the use of <em>E. coli </em>as the preferred indicator for the detection of faecal contamination, not only in drinking water, but also in other matrices as well: first, the finding that some <em>faecal coliforms</em> were non faecal in origin, and second, the development of improved testing methods for<em> E. coli</em>. The faecal coliform definition has also been revised to coincide better with the genetic make-up of its members and now includes newly identified environmental species. As a result, faecal coliforms are increasingly being referred to as <em>thermotolerant</em> coliforms. This, combined with improved detection methods for <em>E. coli</em>, has started a trend toward the use of <em>E. coli</em> in place of thermotolerant coliforms as a more reliable indicator of faecal pollution in drinking water. At present, <em>E. coli</em> appears to provide the best bacterial indication of faecal contamination in drinking water. This is based on the prevalence of thermotolerant (faecal) coliforms in temperate environments as compared to the rare incidence of<em> E. coli</em>, the prevalence of <em>E. coli </em>in human and animal faeces as compared to other thermotolerant coliforms, and the availability of affordable, fast, sensitive, specific and easier to perform detection methods for <em>E. coli</em>

Hit and run versus long-term activation of PARP-1 by its different domains fine-tunes nuclear processes.

Poly(ADP-ribose) polymerase 1 (PARP-1) is a multidomain multifunctional nuclear enzyme involved in the regulation of the chromatin structure and transcription. PARP-1 consists of three functional domains: the N-terminal DNA-binding domain (DBD) containing three zinc fingers, the automodification domain (A), and the C-terminal domain, which includes the protein interacting WGR domain (W) and the catalytic (Cat) subdomain responsible for the poly(ADP ribosyl)ating reaction. The mechanisms coordinating the functions of these domains and determining the positioning of PARP-1 in chromatin remain unknown. Using multiple deletional isoforms of PARP-1, lacking one or another of its three domains, as well as consisting of only one of those domains, we demonstrate that different functions of PARP-1 are coordinated by interactions among these domains and their targets. Interaction between the DBD and damaged DNA leads to a short-term binding and activation of PARP-1. This hit and run activation of PARP-1 initiates the DNA repair pathway at a specific point. The long-term chromatin loosening required to sustain transcription takes place when the C-terminal domain of PARP-1 binds to chromatin by interacting with histone H4 in the nucleosome. This long-term activation of PARP-1 results in a continuous accumulation of pADPr, which maintains chromatin in the loosened state around a certain locus so that the transcription machinery has continuous access to DNA. Cooperation between the DBD and C-terminal domain occurs in response to heat shock (HS), allowing PARP-1 to scan chromatin for specific binding sites

CK2 kinase activity but not its binding to CK2 promoter regions is implicated in the regulation of CK2α and CK2β gene expressions

Protein kinase CK2, a ubiquitous serine/threonine kinase in control of a variety of crucial cellular functions, is composed of catalytic a- and a0-subunits and non-catalytic b-subunits which form holoenzymes such as CK2(ab)2, CK2aa\u27b2, or CK2(a\u27b)2. In addition, there is sample evidence for the occurrence of the individual subunits beside the holoenzyme. While the CK2 subunits are well analyzed on the protein level, only little is known about the regulation of their transcription. The existence of multiple forms of CK2 subunits raised the question about a mutual regulation of their expression. Here we defined two 50-upstream regions of the CK2alpha and the CK2beta genes, respectively, as sequences with promoter activities. We found that CK2alpah and CK2alpha\u27 stimulated the expression of the reporter constructs whereas, CK2beta was inactive. Using chromatin immunoprecipitation assays, we were unable to detect binding of endogenous CK2 subunits to these promoter sequences in vivo. However, it turned out that inhibition of the kinase activity of CK2 attenuated the promoter activity indicating that CK2alpha and CK2alpha\u27 might regulate their gene expression indirectly by phosphorylation reactions. Thus, we have shown here (i) that under normal physiological conditions CK2 does not bind to CK2 promoter regions and (ii) that the CK2 kinase activity is implicated in the regulation of its own expression

Reducing Soil CO2 Emission and Improving Upland Rice Yield with no-Tillage, Straw Mulch and Nitrogen Fertilization in Northern Benin

To explore effective ways to decrease soil CO2 emission and increase grain yield, field experiments were conducted on two upland rice soils (Lixisols and Gleyic Luvisols) in northern Benin in West Africa. The treatments were two tillage systems (no-tillage, and manual tillage), two rice straw managements (no rice straw, and rice straw mulch at 3 Mg ha-1) and three nitrogen fertilizers levels (no nitrogen, recommended level of nitrogen: 60 kg ha-1, and high level of nitrogen: 120 kg ha-1). Potassium and phosphorus fertilizers were applied to be non-limiting at 40 kg K2O ha-1 and 40 kg P2O5 ha-1. Four replications of the twelve treatment combinations were arranged in a randomized complete block design. Soil CO2 emission, soil moisture and soil temperature were measured at 5 cm depth in 6 to 10 days intervals during the rainy season and every two weeks during the dry season. Soil moisture was the main factor explaining the seasonal variability of soil CO2 emission. Much larger soil CO2 emissions were found in rainy than dry season. No-tillage planting significantly reduced soil CO2 emissions compared with manual tillage. Higher soil CO2 emissions were recorded in the mulched treatments. Soil CO2 emissions were higher in fertilized treatments compared with non fertilized treatments. Rice biomass and yield were not significantly different as a function of tillage systems. On the contrary, rice biomass and yield significantly increased with application of rice straw mulch and nitrogen fertilizer. The highest response of rice yield to nitrogen fertilizer addition was obtained for 60 kg N ha-1 in combination with 3 Mg ha-1 of rice straw for the two tillage systems. Soil CO2 emission per unit grain yield was lower under no-tillage, rice straw mulch and nitrogen fertilizer treatments. No-tillage combined with rice straw mulch and 60 kg N ha-1 could be used by smallholder farmers to achieve higher grain yield and lower soil CO2 emission in upland rice fields in northern Benin

Technical-Economic Prefeasibility Assessment of an off-grid Mini-Hydro Power Plant for an Agribusiness Resort in Kaduna Nigeria

Clean energy technologies are beginning to receive attention in Nigeria to offset the increasing greenhouse gas emissions. These emissions are associated to the wide use of small-scale fossil-fuel-powered generators by about 55% of its 180-million people yet to be connected to the grid. While a large hydropower potential exists in Nigeria, even above the total electricity demand of the country, by 2013 this technology only accounted for about 32% of the total installed generation capacity connected to the grid. Previous studies have limited results in terms of technical, economic and environmental evidences that can drive choices towards small hydro and other clean energy projects for users and technology providers in Nigeria. This study uses the RETScreen Software to analyse the technical, economic and environmental aspects of a proposed mini-hydro power plant on the Tuwan River, to supply part of the energy needs of Tuwan Agribusiness Resort (TAR) located in Madakiya district, a rural community in Kaduna State, Nigeria. The volumetric flow and gross head of the chosen river were measured and the power generation system design yielded a 21kW power output, capable to partially offset the present use of diesel generators and achieve a 307.4 tCO2 equivalent GHG emission reduction. The financial analysis showed an attractive Internal Rate of Return (IRR) of 68.1% and NPV of 568,178 USD (11% discount rate), owing to the high potential of the project to attract grants and tax rebates, which were put into consideration in the financial analysis. This study is important for Tuwan Agribusiness Resort, an agribusiness service provision outfit with a potential to create over 1000 jobs when fully operationa

Capability in the digital: institutional media management and its dis/contents

This paper explores how social media spaces are occupied, utilized and negotiated by the British Military in relation to the Ministry of Defence’s concerns and conceptualizations of risk. It draws on data from the DUN Project to investigate the content and form of social media about defence through the lens of ‘capability’, a term that captures and describes the meaning behind multiple representations of the military institution. But ‘capability’ is also a term that we hijack and extend here, not only in relation to the dominant presence of ‘capability’ as a representational trope and the extent to which it is revealing of a particular management of social media spaces, but also in relation to what our research reveals for the wider digital media landscape and ‘capable’ digital methods. What emerges from our analysis is the existence of powerful, successful and critically long-standing media and reputation management strategies occurring within the techno-economic online structures where the exercising of ‘control’ over the individual – as opposed to the technology – is highly effective. These findings raise critical questions regarding the extent to which ‘control’ and management of social media – both within and beyond the defence sector – may be determined as much by cultural, social, institutional and political influence and infrastructure as the technological economies. At a key moment in social media analysis, then, when attention is turning to the affordances, criticisms and possibilities of data, our research is a pertinent reminder that we should not forget the active management of content that is being similarly, if not equally, effective

Concurrent Acquisition of a Single Nucleotide Polymorphism in Diverse Influenza H5N1 Clade 2.2 Sub-clades

Highly pathogenic Influenza A H5N1 was first identified in Guangdong Province in 1996, followed by human cases in Hong Kong in 1997 1,2. The number of confirmed human cases now exceeds 300 and the associated Case Fatality Rate exceeds 60% 3. The genetic diversity of the serotype continues to increase. Four distinct clades or sub-clades have been linked to human cases 4-7. The gradual genetic changes identified in the sub-clades have been attributed to copy errors by viral encoded polymerases that lack an editing function, thereby resulting in antigenic drift 8. We report here the concurrent acquisition of the same polymorphism by multiple, genetically distinct, clade 2.2 sub-clades in Egypt, Russia, Kuwait, and Ghana. These changes are not easily explained by the current theory of &#x201c;random mutation&#x201d; through copy error, and are more easily explained by recombination with a common source. The recombination role is further supported by the high fidelity replication in swine influenza 9 and aggregation of single nucleotide polymorphisms in H5N1 clade 2.2 hemagglutinin 10

Improving soil quality and upland rice yield in northern Benin with no-tillage, rice straw mulch and nitrogen fertilization

Management practices that simultaneously improve soil properties and yield are crucial to sustain high crop production and minimize detrimental impact on the environment. The objective of this study was to determine the influence of tillage, rice straw mulch and nitrogen fertilization on soil quality and upland rice yield in northern Benin, West Africa. The 2-year (2014-2015) field experiment was conducted with two tillage systems (no-tillage, and manual tillage), two rice straw managements (no rice straw, and rice straw mulch at 3 Mg ha-1) and three nitrogen fertilizer levels (no nitrogen, moderate level of nitrogen: 60 kg ha-1, and high level of nitrogen: 120 kg ha-1). Rice yield was not significantly different as a function of tillage systems. On the contrary, rice yield significantly increased with application of rice straw mulch and nitrogen fertilizer. The highest response of rice yield to nitrogen fertilizer addition was obtained for 60 kg N ha-1 in combination with 3 Mg ha-1 of rice straw for the two tillage systems. Soil moisture and soil microbial carbon were higher under no-tillage, rice straw mulch and nitrogen fertilizer. No-tillage combined with rice straw mulch and 60 kg N ha-1 could be used by smallholder farmers to improve soil quality and achieve higher grain yield in upland rice fields in northern Benin. (Résumé d'auteur