Monitoring of Urban Growth and its Related Environmental Impacts: Niamey Case Study (Niger)

AbstractThe present contribution is about a preliminary study of the evolution of Niamey city (Niger) during last decades.Recent advances in remote sensing, both in satellite hardware technology and image availability development, provide opportunities image collection and multitemporal analysis on urban form and size that can be useful for policy and planning. Some opportunities for, and limitations on, monitoring urban growth using remote sensing data are shown in the present contribution; moreover examples of environmental impacts of urban growth, as monitored with remote sensing, are provided in order to define future development of dumps and quarries and its environmental impacts on Niamey city

Genetic microheterogeneity and phenotypic variation of Helicobacter pylori arginase in clinical isolates

BACKGROUND: Clinical isolates of the gastric pathogen Helicobacter pylori display a high level of genetic macro- and microheterogeneity, featuring a panmictic, rather than clonal structure. The ability of H. pylori to survive the stomach acid is due, in part, to the arginase-urease enzyme system. Arginase (RocF) hydrolyzes L-arginine to L-ornithine and urea, and urease hydrolyzes urea to carbon dioxide and ammonium, which can neutralize acid. RESULTS: The degree of variation in arginase was explored at the DNA sequence, enzyme activity and protein expression levels. To this end, arginase activity was measured from 73 minimally-passaged clinical isolates and six laboratory-adapted strains of H. pylori. The rocF gene from 21 of the strains was cloned into genetically stable E. coli and the enzyme activities measured. Arginase activity was found to substantially vary (>100-fold) in both different H. pylori strains and in the E. coli model. Western blot analysis revealed a positive correlation between activity and amount of protein expressed in most H. pylori strains. Several H. pylori strains featured altered arginase activity upon in vitro passage. Pairwise alignments of the 21 rocF genes plus strain J99 revealed extensive microheterogeneity in the promoter region and 3' end of the rocF coding region. Amino acid S232, which was I232 in the arginase-negative clinical strain A2, was critical for arginase activity. CONCLUSION: These studies demonstrated that H. pylori arginase exhibits extensive genotypic and phenotypic variation which may be used to understand mechanisms of microheterogeneity in H. pylori

Georesources and Environmental Problems in Niamey City (Niger): A Preliminary Sketch

AbstractThe present paper is about a preliminary study of the georesources of Niamey (Niger). The main goals are the qualitative and quantitative characterization of surface water, groundwater, and aggregates. There was a census of the wells and quarries, an in situ characterization and a consequent sampling survey. Laboratory analyses were performed to evaluate chemical and physical features of water and aggregates. Thanks to a dedicated Geodatabase, schematic forms reporting the available data of wells and quarries were produced. The study evidenced the actual condition of surface water, groundwater and active and closed quarries, also highlighting local phenomena of pollution

Approach to leg edema

Edema is defined as a palpable swelling caused by an increase in interstitial fluid volume. Leg edema is a common problem with a wide range of possible causes and is the result of an imbalance in the filtration system between the capillary and interstitial spaces. Major causes of edema include venous obstruction, increased capillary permeability and increased plasma volume secondary to sodium and water retention. In both hospital and general practice, the patient with a swollen leg presents a common dilemma in diagnosis and treatment. The cause may be trivial or life-threatening and it is often difficult to determine the clinical pathway. The diagnosis can be narrowed by categorizing the edema according to its duration, distribution (unilateral or bilateral) and accompanying symptoms. This work provides clinically oriented recommendations for the management of leg edema in adults

Genetic Microheterogeneity and Phenotypic Variation of \u3ci\u3eHelicobacter pylori\u3c/i\u3e Arginase in Clinical Isolates

Background: Clinical isolates of the gastric pathogen Helicobacter pylori display a high level of genetic macro- and microheterogeneity, featuring a panmictic, rather than clonal structure. The ability of H. pylori to survive the stomach acid is due, in part, to the arginase-urease enzyme system. Arginase (RocF) hydrolyzes L-arginine to L-ornithine and urea, and urease hydrolyzes urea to carbon dioxide and ammonium, which can neutralize acid. Results: The degree of variation in arginase was explored at the DNA sequence, enzyme activity and protein expression levels. To this end, arginase activity was measured from 73 minimally-passaged clinical isolates and six laboratory-adapted strains of H. pylori. The rocF gene from 21 of the strains was cloned into genetically stable E. coli and the enzyme activities measured. Arginase activity was found to substantially vary (\u3e100-fold) in both different H. pylori strains and in the E. coli model. Western blot analysis revealed a positive correlation between activity and amount of protein expressed in most H. pylori strains. Several H. pylori strains featured altered arginase activity upon in vitro passage. Pairwise alignments of the 21 rocF genes plus strain J99 revealed extensive microheterogeneity in the promoter region and 3\u27 end of the rocF coding region. Amino acid S232, which was I232 in the arginase-negative clinical strain A2, was critical for arginase activity. Conclusion: These studies demonstrated that H. pylori arginase exhibits extensive genotypic and phenotypic variation which may be used to understand mechanisms of microheterogeneity in H. pylori

ChVlig can support mtDNA replication at reduced copy number.

<p>A, 4B6 cells were sequentially transduced with retroviruses encoding ChVLigAnd Cre recombinase, and Lig3 excision was tested in 13 resulting clones. B, resulting clones have variable mtDNA copy number as compared to an arbitrarily chosen clone#1. C, Clones #5, #6, and #13 maintained >90% reduced mtDNA copy number upon 3-week propagation in the selective medium. D, mtDNA copy number in the 4B6 cells transduced with ChVlig, two clones (#3 and #14), which were derived from the original ChVlig-transduced clone by Lig3 excision, and in the clone#14 after transduction with either WT or catalytically inactive mLig3.</p

A Method for In Situ Reverse Genetic Analysis of Proteins Involved mtDNA Replication

The unavailability of tractable reverse genetic analysis approaches represents an obstacle to a better understanding of mitochondrial DNA replication. Here, we used CRISPR-Cas9 mediated gene editing to establish the conditional viability of knockouts in the key proteins involved in mtDNA replication. This observation prompted us to develop a set of tools for reverse genetic analysis in situ, which we called the GeneSwap approach. The technique was validated by identifying 730 amino acid (aa) substitutions in the mature human TFAM that are conditionally permissive for mtDNA replication. We established that HMG domains of TFAM are functionally independent, which opens opportunities for engineering chimeric TFAMs with customized properties for studies on mtDNA replication, mitochondrial transcription, and respiratory chain function. Finally, we present evidence that the HMG2 domain plays the leading role in TFAM species-specificity, thus indicating a potential pathway for TFAM-mtDNA evolutionary co-adaptations

The effect of LigA on mtDNA copy number in 4B6 cells.

<p>A, 4B6 cells were transduced with a retrovirus encoding LigA without MTS, and mtDNA copy number was determined in four resulting subclones. B, Subclone #11 was transduced with a retrovirus encoding Cre recombinase, and genomic DNA from ten clones was PCR-analyzed for the presence of unexcised Lig3 allele (Lig3), excised Lig3 allele (ΔLig3), ρ⁰ phenotype (mtDNA and nDNA primers), and for the presence of LigA (LigA). Primer sets and primer sequences are listed in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152705#pone.0152705.s005" target="_blank">S1 Table</a>.</p

Respiration and growth rates.

<p>4B6 cells and cloned with LigA-supported mtDNA replication #1,#2, and #4 were transduced with retroviruses encoding either WT or catalytically inactive K510V mutant mLig3. A-C, OCR was determined in the parental (A) and transduced (B and C) cells. D, doubling time of the resulting clones. ***, P<0.001, two-way ANOVA with Dunnett’s post-hoc test.</p

Presequence-independent mitochondrial import of LigA-myc is inefficient.

<p>A. Genotyping cell lines transduced with either MTS-LigA-myc or with LigA-myc; B. mtDNA content in the parental 4B6 cells, and in cells in which mtDNA replication is supported by either MTS-LigA-myc (+MTS) or LigA-myc (No MTS); C. Whole cell and mitochondrial fractions from cells that express either MTS-LigA-myc or LigA-myc were subjected to western blotting with myc-tag antibodies, or with antibodies against reference proteins TOM70 (resides in the mitochondrial outer membrane) or MnSOD (resides in the mitochondrial matrix).</p