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Evaluation of the Efficacy of Albizia zygia Extracts on Bacterial Inhibition in Aquatic Microcosm

Journal of Geoscience and Environment Protection 2023年第7期11卷 227-241页

作者： Yves Yogne Poutoum Luciane Marlyse moungang Blandine Pulcherie Tamatcho Kweyang Thierry Youmbi Fonkui Golda Reine Zame Meva’a Aurélie Dzenga Njeunkam mouhama Sani Adams Ibn Rabiou moïse nola Department of Animal Biology and Physiology Faculty of Sciences University of Yaounde I Yaounde Cameroon Department of Microbiology Faculty of Sciences University of Yaounde I Yaounde Cameroon Department of Biotechnology and Food Technology Faculty of Sciences Doornfontein Campus University of Johannesburg Johannesburg South Africa

The objective of this study is the phytochemical analysis and the determination of the antibacterial activity of aqueous and hydro-ethanolic extracts obtained from the leaves and bark of the trunk of Albizia zygia, against Escherichia coli and Salmonella typhi bacteria in aquatic microcosms. Phytochemical screening was performed as described by Pareck. The results obtained show that the hydro-ethanolic and aqueous extracts of Albizia zygia trunk bark recorded higher extraction yields (26.71% and 33.2% respectively) compared to the aqueous and hydro-ethanolic extracts of leaves of the same plant. secondary metabolites with antibacterial activities such as anthraquinones, anthocyanins, flavonoids, polyphenols, tannins and saponins were found in both types of extracts. Flavonoids and anthocyanins were relatively more abundant than the other chemical constituents. The highest cellular inhibition rate of Escherichia coli was 99.88%, obtained after 9 hours of exposure in the hydro-ethanolic extract solution of trunk bark at the concentration 1.5 g/L. The Salmonella typhi rate was 99.95% after 9 hours of exposure of bacterial cells to the hydro-ethanol extract of the bark of the trunk at the concentration 1.5 g/L. This rate increased proportionally with the bacterial-extract contact time. The temperature of the medium did not significantly influence bacterial inhibition (P > 0.05). The obtained results justify the use of the plant Albizia zygia in the reduction of the flow of bacterio-pollutants contained in water intended for consumption.

关键词： Albizia zygia Extract Phytochemical Screening Bacterial Inhibition Aquatic Microcosms

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Diversity and Structure of the Prokaryotic Communities Indigenous to Two Volcanic Lakes: Nyos and monoun in Cameroon

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Open Journal of Ecology 2020年第9期10卷 632-650页

作者： Paul-Alain Nana moïse nola Geneviève Bricheux Zéphyrin Fokam Pierre Ngassam Dickson Achuo Enah Jonathan Colombet Agnès Vellet Anne mone Viviane Ravet Didier Debroas Télesphore Sime-Ngando Department of Oceanography Institute of Fisheries and Aquatic Sciences University of Douala Douala Cameroon Laboratory of Hydrobiology and Environment Faculty of Science University of Yaoundé I Yaoundé Cameroon Laboratory Microorganisms: Genome and Environment UMR CNRS 6023 Clermont Auvergne University Clermont-Ferrand France Department of Biology Higher Teacher Training College University of Bamenda Bamenda Cameroon

This study explores the diversity and structure of prokaryotic communities (Archaea and Bacteria) of 2 tropical volcanic lakes (Nyos and monoun) in Cameroon, using 16SrRNA sequences. Metagenomics analysis of sequences showed that most OTUs (Operational Taxonomic Units) were associated with 26 phyla (23 for Bacteria and 3 for Archaea) in Nyos and 36 phyla (33 for Bacteria and 3 for Archaea) in monoun. In both lakes, Proteobacteria for Bacteria and Crenarchaea for Archaea were predominant and present at all depths but in different proportions. Bacterial community compositions were generally dominated by members of Proteobacteria, Firmicutes, Actinobacteria, Chloroflexi and Bacteroidetes covering about 98% of the sequences. Crenarchaea, Thaumarchaea and Euryarchaea were the three main phyla of Archaea common to both lakes. The amount of virus and total bacteria was determined by flow cytometry technic and the evaluated ratio ranged from 0.2 to 1.2 at Nyos and from 0.6 to 2.6 at monoun. For both lakes, the correlation was very significant between viruses and total bacteria. The depth-dependent variability is discussed with chemical and physical environmental parameters. These could significantly influence virus-mediated bacterial lysis and abundance and vertical stratification of the prokaryotic community.

关键词： Bacteria Flow Cytometry Lakes Nyos and monoun OTUs Viruses

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Bacteriological and Physicochemical Quality of Groundwater of Mbankomo Municipality(Center Region,Cameroon)

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Journal of Environmental Science and Engineering(B) 2023年第3期12卷 115-127页

作者： Murielle Patricia Mabou Tokam Antoine Tamsa Arfao Fils Mamert Onana Ernest Koji Vanelle Lontchi segnou Yves Poutoum Yogne Awawou Manouore Njoya Ornel Kadji Tchantcha Ahmadou Fadimatou Sylvie Chinche Belengfe Edith Brunelle mouafo Tamnou moïse nola Department of Animal Biology and Physiology Faculty of ScienceUniversity of DoualaDouala 24157Cameroon Hydrobiology and Environment Laboratory University of Yaounde 1Faculty of SciencesYaounde 812Cameroon Laboratoire d’Application et d’Analyses Médicales Institut Supérieur des Sciences et Techniques de la Santéet du Management de GarouaBP.51 GarouaCameroun Department of Aquatic Ecosystems Management Institute of Fisheries and Aquatic SciencesUniversity of DoualaDoualaCameroon Laboratory S3MN2E Faculty of SciencesMohammed-V University RabatAv.Ibn-BattoutaRabatMorocco 8007.N.U.North Africa Department of Fisheries and Aquatic Resources Management Faculty of Agriculture and Veterinary MedicineUniversity of BueaBuéa 63Cameroon

A study to evaluate the physico-chemical and bacteriological quality of groundwater was carried out in the commune of Mbankomo(Centre-Cameroon)at 4 wells and 4 springs during the period from March to *** physico-chemical parameters were measured by the standard *** bacteria of fecal contamination,namely HAB(Heterotrophic Aerobic Bacteria),total and faecal coliforms(Escherichia coli),and faecal streptococci were isolated by the surface spreading technique on PCA(Plate Count Agar),Endo and BEA(Bile Esculin Azide)agar respectively,and sulphite-reducing clostridia by the incorporation method on Tryptone Sulfite Cycloserine(TSC)*** a physico-chemical point of view,the groundwater in Mbamkomo is characterized by an average temperature(24.24±0.24°C);it is polluted with organic matter,acid and poorly *** was noted from a bacteriological point of view that these waters have a high and varied bacterial load with an average value of 100.8 × 10^(5) CFU/100 mL for coliforms,16.3 × 10^(5) CFU/100 mL for fecal streptococci,5.6 × 10^(5) CFU/100 mL for Escherichia coli and 4.8 ×10^(²)CFU/100 mL for Clostridium *** concentrations are all higher than the WHO(World Health Organization)standards which are set at 0 CFU/100 mL for coliforms,fecal streptococci and Clostridium perfringens and indicate fecal pollution of these *** coli cell densities were significantly correlated with dissolved oxygen in the water(r=0.510;pse waters is favored by their proximity to pollution sources,poor maintenance and poor protection of the *** waters,without any treatment,are not recommended for human consumption according to the standards of the WHO.

关键词： Groundwater physico-chemical quality bacteriological quality.

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Strongly Convergent Approximations to Fixed Points of Total Asymptotically Nonexpansive Mappings

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Acta Mathematica Sinica,English series 2008年第6期24卷 1005-1022页

作者： Yakov ALBER Rafa ESPínola Pepa LORENZO Department of Mathematics The Technion-Israel Institute of Technology32000 HaifaIsrael Departamento de Andlisis Matemdtico Universidad de SevillaP.O.Box 116041080-SevilleSpain

In this work we prove a new strong convergence result of the regularized successive approximation method given by yn＋1 = qnz0 ＋（1 - qn）T^nyn, n = 1, 2,…,where lim n→∞ qn = 0 and ∞∑n=1 qn=∞ for T a total asymptotically nonexpansive mapping, i.e., T is such that ││T^n x - T^n y││ ≤ x - y ││ ＋ kn^（1）φ（││x - y││）＋ kn^（2）,where kn^1 and kn^2 are real null convergent sequences and φ：R^＋→R^＋ is continuous such that φ（0）=0 and limt→∞φ（t）/t≤ C for a certain constant C 〉 0. Among other features, our results essentially generalize existing results on strong convergence for T nonexpansive and asymptotically nonexpansive. The convergence and stability analysis is given for both self- and nonself-mappings.

关键词： asymptotically nonexpansive mappings best approximation fixed point duality map iteration schemes

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Variation in abundance and habitat relationship of three understory insectivorous birds in a disturbed landscape of Neotropical dry forest of Colombia

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Avian Research 2020年第3期11卷 265-276页

作者： Camilo Loaiza Olga Lmontenegro David King Manuel Spínola Lilibeth Arinda Palacio Agustín Rudas Instituto de Ciencias Naturales Universidad Nacional de ColombiaBogotáColombia Northern Research Station USDA Forest ServiceUniversity of Massachusetts204 Holdsworth HallAmherstMA 01003USA Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad NacionalApartado1350-3000 HerediaCosta Rica.

Background:Evaluating relationships between avian populations and their habitat is important for understanding the biology of these species and for management decisions that improve the effectiveness of restoration *** investigated how habitat variation along a disturbance gradient affected the abundance of three insectivorous bird species,White-bellied Antbird(Myrmeciza longipes),Barred Antshrike(Thamnophilus doliatus),and Pale-breasted Spinetail(Synallaxis albescens)in a Neotropical dry forest remnant in central ***:The study area,which is located in Magdalena Valley,is under ecological restoration after the construction of the“El Quimbo”hydroelectric dam,with a gradient of habitat conditions,from relatively advanced secondary growth to recently disturbed *** conducted bird surveys and quantified the habitat conditions from June 2018 to June *** compared the relative abundance of the birds among the three zones with increasing disturbance and modeled the relationship between the bird abundance with the micro-and landscape-habitat conditions,with Poisson generalized linear model ***:The relative abundance of the three bird species varied according to the habitat features and disturbance *** abundance of White-bellied Antbirds was higher in forests and thickets than shrubland fragments;Barred Antshrike was more abundant in shrubland and thickets than in forest fragments,and Pale-breasted Spinetail had the highest abundance in shrubland and the lowest in forest *** abundance of both White-bellied Antbird and Pale-breasted Spinetail did not differ among zones with different levels of disturbance,while the abundance of Barred Antshrike decreased in zones with more ***:There were significant differences in the habitat relationships of the three understory insectivorous species along the disturbance gradient,although these species were within the same trophic *** bird species prefer

关键词： Bird population ecology Generalized linear models Wildlife habitat restoration

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Kindlin-1 drives early steps of breast cancer metastasis

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Cancer Communications 2022年第10期42卷 1036-1040页

作者： Florian Bonin Aurélie Chiche Zakia Tariq Paula Azorin Sébastien nola Rosette Lidereau Keltouma Driouch Genetics Department Institut CurieParis 75005France Cell Biology and Cancer Department/Unit 144 Institut Curie/Centre National de Recherche ScientifiqueParis 75005France Department of Developmental&Stem Cell Biology/Unit 3738 Institut Pasteur/Centre National de Recherche ScientifiqueParis 75015France Membrane Traffic in Health And Brain Disease/Unit 1266 Institute of Psychiatry and Neuroscience of Paris/Institut National de la Santéet de la Recherche MédicaleUniversitéde ParisParis 75014France

Dear Editor,Kindlin-1 plays a major role in the activation of integrins[1].Kindlin-1 is often overexpressed in ***-1 overexpression has been associated with a higher propensity of breast cancer patients to metastasize to the lungs[2,3].Furthermore,Kindlin-1 depletion in mouse models was found to inhibit tumor growth and lung metastasis[3,4].However,the underlying mechanisms remain poorly explored.

关键词： metastasis Kindlin breast

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Water Allocation Strategies: Experimental Evidence from Uzbekistan

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Journal of Water Resource and Protection 2018年第1期10卷 20-40页

作者： Andrey Zaikin Ana Espínola-Arredondo Alejandro Prera School of Economic Sciences Washington State University Pullman USA

Irrigation water is a scarce common-pool resource in Uzbekistan, which leads to an increasing competition over its allocation among farmers. We examine how the management of this resource affects individual strategic behavior and how its availability (vis-a-vis scarcity vs. non-scarcity) impacts cooperation. We conduct a field experiment in Uzbekistan where two policies are analyzed: penalty and bonus. Our findings suggest that both penalty and bonus mechanisms are effective in reducing individual water appropriation compared to the case in which these policies are absent. However, in terms of reducing overall water appropriation, the bonus mechanism is the most effective in preserving the resource stock. Therefore, policymakers should have a degree of flexibility regarding the selection of a mechanism to reduce water consumption. We also find that subjects exhibit different appropriation behaviors depending on their location within the irrigation system, with upstream users being more sensitive to water reduction than downstream users.

关键词： Common-Pool Resources Field Experiment Non-Cooperative Games Uzbekistan Water

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Silver fir tree-ring fluctuations decrease from north to south latitude—total solar irradiance and NAO are indicated as the main influencing factors

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Forest Ecosystems 2023年第6期10卷 717-731页

作者： Vaclav Simůnek Anna Prokůpkova Zdenek Vacek Stanislav Vacek Jan Cukor Jirí Remes Vojtech Hajek Giuseppe D'Andrea Martin Salek Paola nola Osvaldo Pericolo Sarka Holzbachova Francesco Ripullone Faculty of Forestry and Wood Sciences Czech University of Life Sciences PragueKamýcka 129CZ—16500Prague 6SuchdolCzech Republic Forestry and Game Management Research Institute v.v.iStrnady 13625202JílovisteCzech Republic Czech Academy of Sciences Institute of Vertebrate BiologyKvetna 860365BrnoCzech Republic Department of Earth and Environmental Sciences University of PaviaVia S.Epifanio 14I-27100PaviaItaly Forests of the Czech Republic SOEPremyslova 1106/19NovýHradec Kralove50008Hradec KraloveCzech Republic School of Agricultural Forestry and Environmental SciencesUniversity of BasilicataViale dell’Ateneo Lucano 10I-85100PotenzaItaly Faculty of Environmental Sciences Czech University of Life Sciences PragueKamýcka 129CZ—16500PragueSuchdolCzech Republic

Silver fir(Abies alba Mill.)is a flexible European tree species,mainly vegetating within the mountainous regions of Europe,but its growth responses across its latitudinal and longitudinal range have not yet been satisfactorily verified under changing environmental *** study describes the tree-ring increment of silver fir in research plots across a latitudinal gradient from the northern range in Czechia(CZ),through Croatia(HR)to the southernmost range in Italy(IT).The research aims to analyze in detail the dynamics and cyclicity of the ringwidth index(RWI)and how it relates to climatic factors(temperature and precipitation),the North Atlantic Oscillation(NAO),and total solar irradiance(TSI),including the determination of *** results show that the main drivers affecting fir growth are the seasonal NAO index and *** temperatures affect RWI early in the vegetation season,while lack of precipitation during the summer is a limiting factor for fir growth,especially in *** temperatures and temperatures in June and July negatively impact,while seasonal precipitation totals in the same months positively influence the RWI in all research plots across *** longest growth cycles in fir RWI were recorded in the northernmost studied plots in *** cyclical fluctuations recede approaching the *** cyclic increase in RWI is related to the TSI,which decreases its effect from north to *** TSI's effects vary,positively impacting CZ but negatively influencing HR while remaining relatively neutral in *** the other hand,seasonal NAO tends to negatively affect silver fir growth in HR and CZ but has a mildly positive effect in *** conclusion,the TSI and the influence of the seasonal NAO index are prevalent in the fir RWI and are accompanied by a greater cyclicity of RWI in Central Europe(temperature optimum)than in the Italian Mediterranean region,where this tree species is limited by climatic conditions,especially lack of pre

关键词： Abies alba Mill Tree-rings Solar cycle North Atlantic oscillation Precipitation Temperature

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