PCR-Ribotyping of Xenorhabdus andPhotorhabdus Isolates from the Caribbean Region in Relation to the Taxonomy and Geographic Distribution of Their Nematode Hosts

1998 ◽  
Vol 64 (11) ◽  
pp. 4246-4254 ◽  
Author(s):  
Marion Fischer-Le Saux ◽  
Hervé Mauléon ◽  
Philippe Constant ◽  
Brigitte Brunel ◽  
Noël Boemare
Keyword(s):  
Entomopathogenic Nematodes ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Caribbean Region ◽  
Polymorphism Analysis ◽  
Caribbean Islands ◽  
Pcr Ribotyping ◽  
The Caribbean ◽  
And Cluster Analysis ◽  
Reference Strains

ABSTRACT The genetic diversity of symbiotic Xenorhabdus andPhotorhabdus bacteria associated with entomopathogenic nematodes was examined by a restriction fragment length polymorphism analysis of PCR-amplified 16S rRNA genes (rDNAs). A total of 117 strains were studied, most of which were isolated from the Caribbean basin after an exhaustive soil sampling. The collection consisted of 77 isolates recovered from entomopathogenic nematodes in 14 Caribbean islands and of 40 reference strains belonging toXenorhabdus and Photorhabdus spp. collected at various localities worldwide. Thirty distinctive 16S rDNA genotypes were identified, and cluster analysis was used to distinguish the genus Xenorhabdus from the genusPhotorhabdus. The genus Xenorhabdusappears more diverse than the genusPhotorhabdus, and for both genera the bacterial genotype diversity is in congruence with the host-nematode taxonomy. The occurrence of symbiotic bacterial genotypes was related to the ecological distribution of host nematodes.

scholarly journals Unraveling the Etiology of North American Grapevine Yellows (NAGY): Novel NAGY Phytoplasma Sequevars Related to ‘Candidatus Phytoplasma pruni’

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1087-1097 ◽  
Author(s):  
Robert E. Davis ◽  
Ellen L. Dally ◽  
Yan Zhao ◽  
Ing-Ming Lee ◽  
Wei Wei ◽  
...  
Keyword(s):  
16S Rdna ◽  
North American ◽  
Phylogenetic Analyses ◽  
New York State ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Vitis Vinifera L ◽  
Polymorphism Analysis ◽  
Ribosomal Protein Genes ◽  
Grapevine Yellows

North American grapevine yellows (NAGY) disease has sometimes been attributed to infection of Vitis vinifera L. by Prunus X-disease phytoplasma (‘Candidatus Phytoplasma pruni’) but this attribution may not be fully adequate. In this study, phytoplasma strains related to ‘Ca. Phytoplasma pruni’ were found in NAGY-diseased grapevines in Maryland, Pennsylvania, Virginia, Ohio, Missouri, and New York State. Based on restriction fragment length polymorphism analysis of 16S ribosomal RNA gene (16S rDNA) sequences, the strains (termed NAGYIII strains) were classified in group 16SrIII (X-disease group) but they contained a recognition site for the restriction endonuclease MseI that is not present in the 16S rDNA of ‘Ca. Phytoplasma pruni’. The 16S rDNA of the strains differed by three or four nucleotides from that of ‘Ca. Phytoplasma pruni’, indicating that they belonged to two novel 16S rDNA sequevars, designated NAGYIIIα and NAGYIIIβ. Both sequevars differed from ‘Ca. Phytoplasma pruni’ by a single base in each of three regions corresponding to species-unique (signature) sequences described for ‘Ca. Phytoplasma pruni’. Phylogenetic analyses of 16S rRNA genes and SecY proteins, and single-nucleotide polymorphism analyses of secY and ribosomal protein genes, further distinguished the two grapevine sequevar lineages from one another and from ‘Ca. Phytoplasma pruni’. The NAGYIIIα and NAGYIIIβ sequevars also differed from ‘Ca. Phytoplasma pruni’ in regions of the folded SecY protein that are predicted to be near or exposed at the outer surface of the phytoplasma membrane. No evidence indicated that diseased grapevines contained any phytoplasma strain conforming to ‘Ca. Phytoplasma pruni’ sensu stricto. Because the NAGYIII sequevars have not been reported in X-disease, a question is raised as to whether NAGYIII and Prunus X-disease are caused by different phytoplasma genotypes.

Composition of the archaeal community involved in methane production during the decomposition of Microcystis blooms in the laboratory

2012 ◽  
Vol 58 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Peng Xing ◽  
Huabing Li ◽  
Qing Liu ◽  
Jiuwen Zheng
Keyword(s):  
Lake Taihu ◽  
Archaeal Community ◽  
Oxygen Depletion ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Methanogenic Community ◽  
Controlled Systems ◽  
Microcystis Blooms ◽  
Different Temperatures

We investigated the microbial processes involved in methane (CH4) production from Microcystis bloom scums at different temperatures. A Microcystis slurry was collected from Lake Taihu and incubated in airtight bottles at 15, 25, and 35 °C. The production of CH4 was monitored, and the emission rate was calculated. The dynamics of the methanogenic community were analyzed by terminal restriction fragment length polymorphism analysis of archaeal 16S rRNA genes. Phylogenetic information for the methanogens was obtained by cloning and sequencing selected samples. Significant CH4 emission from the Microcystis scums was delayed by approximately 12 days by the natural oxygen depletion process, and CH4 production was enhanced at higher temperatures. Phylogenetic analysis indicated that the archaeal community was composed of Methanomicrobiales, Methanobacteriaceae, and a novel cluster of Archaea. An apparent succession of the methanogenic community was demonstrated, with a predominance of Methanobacteriaceae at higher temperatures. Higher temperatures enhanced the methanogenic transformation of the Microcystis biomass and the phylogenetic dominance of hydrogenotrophic methanogens, suggesting that H2 and CO2 might be the primary substrates for CH4 production during Microcystis decomposition without the participation of lake sediment. This work provides insight into the microbial components involved in Microcystis biomass fermentation in controlled systems.

Phenotypic and molecular characterization of chickpea rhizobia isolated from different areas of Tunisia

2007 ◽  
Vol 53 (3) ◽  
pp. 427-434 ◽  
Author(s):  
Boulbaba L’taief ◽  
Bouaziz Sifi ◽  
Maher Gtari ◽  
Mainassara Zaman-Allah ◽  
Mokhtar Lachaâl
Keyword(s):  
Rflp Analysis ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Phenotypic Characteristics ◽  
Cicer Arietinum L ◽  
Mesorhizobium Ciceri ◽  
Length Polymorphisms ◽  
Reference Strains ◽  
Tolerance To Salinity

Several phenotypic markers were used in this study to determine the biodiversity of rhizobial strains nodulating Cicer arietinum L. in various areas of Tunisia. They include symbiotic traits, the use of 21 biochemical substrates, and tolerance to salinity and pH. In addition, restriction fragment length polymorphisms (RFLPs) of PCR-amplified 16S rDNA were compared with those of reference strains. Numeric analysis of the phenotypic characteristics showed that the 48 strains studied fell into three distinct groups. This heterogeneity was highly supported by the RFLP analysis of 16S rRNA genes, and two ribotypes were identified. Chickpea rhizobia isolated from Tunisian soils are both phenotypically and genetically diverse. Results showed that 40 and 8 isolates were assigned, respectively, to Mesorhizobium ciceri and Mesorhizobium mediterraneum .

Life stage descriptions, taxonomic notes, and new records for the mayfly family Leptohyphidae (Ephemeroptera)

Zootaxa ◽  
2003 ◽  
Vol 332 (1) ◽  
pp. 1 ◽  
Author(s):  
DAVID E. BAUMGARDNER ◽  
STEVEN K. BURIAN ◽  
DAVID BASS
Keyword(s):  
United States ◽  
Central America ◽  
New Records ◽  
Life Stage ◽  
Caribbean Region ◽  
Larval Stages ◽  
Caribbean Islands ◽  
Ecological Region ◽  
The Caribbean ◽  
First Time

The larval stages of Tricorythodes fictus Traver, T. cobbi Alba-Tercedor and Flannagan, and T. mosegus Alba-Tercedor and Flannagan are described for the first time based upon reared specimens. The rarely reported Asioplax dolani (Allen) is newly documented from the Austroriparian ecological region of Texas. Leptohyphes zalope Traver, known from the southwestern United States and much of Central America, is newly documented from the Caribbean Islands of Grenada and Tobago. This represents only the second leptohyphid mayfly known from both Continental America and the Caribbean region. Additional Caribbean records of Allenhyphes flinti (Allen) are also given.

scholarly journals Response of Endophytic Bacterial Communities in Potato Plants to Infection with Erwinia carotovora subsp. atroseptica

2002 ◽  
Vol 68 (5) ◽  
pp. 2261-2268 ◽  
Author(s):  
Birgit Reiter ◽  
Ulrike Pfeifer ◽  
Helmut Schwab ◽  
Angela Sessitsch
Keyword(s):  
Plant Stress ◽  
Erwinia Carotovora ◽  
Community Analysis ◽  
Antagonistic Activity ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Blackleg Disease ◽  
Potato Plants

ABSTRACT The term endophyte refers to interior colonization of plants by microorganisms that do not have pathogenic effects on their hosts, and various endophytes have been found to play important roles in plant vitality. In this study, cultivation-independent terminal restriction fragment length polymorphism analysis of 16S ribosomal DNA directly amplified from plant tissue DNA was used in combination with molecular characterization of isolates to examine the influence of plant stress, achieved by infection with the blackleg pathogen Erwinia carotovora subsp. atroseptica, on the endophytic population in two different potato varieties. Community analysis clearly demonstrated increased bacterial diversity in infected plants compared to that in control plants. The results also indicated that the pathogen stress had a greater impact on the bacteria population than the plant genotype had. Partial sequencing of the 16S rRNA genes of isolated endophytes revealed a broad phylogenetic spectrum of bacteria, including members of the α, β, and γ subgroups of the Proteobacteria, high- and low-G+C-content gram-positive organisms, and microbes belonging to the Flexibacter-Cytophaga-Bacteroides group. Screening of the isolates for antagonistic activity against E. carotovora subsp. atroseptica revealed that 38% of the endophytes protected tissue culture plants from blackleg disease.

Building a more Resilient and Low-Carbon Caribbean - Report 1: Climate Resiliency and Building Materials in the Caribbean

2021 ◽  
Author(s):  
Jed Bailey ◽  
Paola Carvajal ◽  
Javier García Fernández ◽  
Christiaan Gischler ◽  
Carlos Henriquez ◽  
...  
Keyword(s):  
Building Materials ◽  
Construction Materials ◽  
Climate Impact ◽  
Climate Impacts ◽  
Economic Losses ◽  
Caribbean Region ◽  
Low Carbon ◽  
Caribbean Islands ◽  
Standards Of Living ◽  
The Caribbean

The Caribbean islands are among the 25 most-vulnerable nations in terms of disasters per-capita or land area, and climate change is only expected to intensify these vulnerabilities. The loss caused by climate events drags the ability of the Caribbean countries to invest in infrastructure and social programs, contributing to slower productivity growth, poorer health outcomes, and lower standards of living. Within this context, building resiliency should become a priority for the Caribbean countries. The series “Building a more resilient and low-carbon Caribbean”, focuses on improving the resiliency, sustainability and decarbonization of the construction industry in the Caribbean. The results show that increasing building resiliency is economically viable for the high-risk islands of the Caribbean, generating long term savings and increasing the infrastructure preparedness to the impacts of CC. Report 1 - Climate Resiliency and Building Materials in the Caribbean, presents a quantification of the economic losses caused by climate impact events in the Caribbean Region and correlate these figures with the most common construction materials, typically used in each of the countries building typologies. The losses caused by hurricanes concentrate mostly in the residential infrastructure and are mainly caused by weaknesses in roofs and their connection to the walls. The analysis suggests that improving the resiliency of outer walls and roofs in the Caribbean could significantly reduce the regions vulnerability to hurricanes and other climate impacts.

Developing future sea level services for Small Island Developing States

2020 ◽  
Author(s):  
Svetlana Jevrejeva ◽  
Judith Wolf ◽  
Andy Matthews ◽  
Joanne Williams ◽  
David Byrne ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Water Level ◽  
Sea Level ◽  
Future Climate Change ◽  
Small Island ◽  
Caribbean Region ◽  
Caribbean Islands ◽  
The Caribbean ◽  
And Sea Level

<p>The Caribbean islands encompass some of the most vulnerable coastlines in terms of sea level rise, exposure to tropical cyclones, changes in waves and storm surges. Climate in the Caribbean is already changing and sea level rise impacts are already being felt. Considerable local and regional variations in the rate, magnitude, and direction of sea-level change can be expected as a result of thermal expansion, tectonic movements, and changes in ocean circulation. Governments in the Caribbean recognise that climate change and sea level rise are serious threats to the sustainable development and economic growth of the Caribbean islands and urgent actions are required to increase the resilience and make decisions about how to adapt to future climate change (Caribbean Marine Climate Change Report Card 2017; IPCC 2014).</p><p>As part of the UK Commonwealth Marine Economies (CME) Programme and through collaboration with local stakeholders in St Vincent, we have identified particular areas at risk from changing water level and wave conditions. The Caribbean Sea, particularly the Lesser Antilles, suffers from limited observational data due to a lack of coastal monitoring, making numerical models even more important to fill this gap. The current projects brings together improved access to tide gauge observations, as well as global, regional and local water level and wave modelling to provide useful tools for coastal planners.</p><p>We present our initial design of a coastal data hub with sea level information for stakeholder access in St. Vincent and Grenadines, Grenada and St Lucia, with potential development of the hub for the Caribbean region. The work presented here is a contribution to the wide range of ongoing activities under the Commonwealth Marine Economies (CME) Programme in the Caribbean, falling within the work package “Development of a coastal data hub for stakeholder access in the Caribbean region”, under the NOC led projects “Climate Change Impact Assessment: Ocean Modelling and Monitoring for the Caribbean CME states”.</p>

scholarly journals Response of Nursery Pigs to a Synbiotic Preparation of Starch and an Anti-Escherichia coli K88 Probiotic

2010 ◽  
Vol 76 (24) ◽  
pp. 8192-8200 ◽  
Author(s):  
D. O. Krause ◽  
S. K. Bhandari ◽  
J. D. House ◽  
C. M. Nyachoti
Keyword(s):  
Escherichia Coli ◽  
Potato Starch ◽  
Control Diet ◽  
Community Analysis ◽  
Positive Control ◽  
Microbial Community Analysis ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
E Coli

ABSTRACT Postweaning diarrhea in pigs is frequently caused by enterotoxigenic Escherichia coli K88 (ETEC). The aim of this study was to test the efficacy of E. coli probiotics (PRO) in young pigs challenged with E. coli K88. We also tested the synbiotic interaction with raw potato starch (RPS), which can be used as a prebiotic. Forty 17-day-old weaned piglets were randomly assigned to four treatments: treatment 1, positive-control diet (C), no probiotics or RPS but containing in-feed antibiotics; treatment 2, probiotic (PRO), no feed antibiotics plus a 50:50 mixture of probiotic E. coli strains UM-2 and UM-7; treatment 3, 14% RPS, no antibiotics (RPS); treatment 4, 14% RPS plus a 50:50 mixture of probiotic E. coli strains UM-2 and UM-7, no antibiotics (PRO-RPS). The pigs were challenged with pathogenic E. coli K88 strains on day 7 of the experiment (24-day-old pigs) and euthanized on day 10 of the experiment (35-day-old pigs). Probiotic and pathogenic E. coli strains were enumerated by selective enrichment on antibiotics, and microbial community analysis was conducted using terminal restriction length polymorphism analysis (T-RFLP) of 16S rRNA genes. The combination of raw potato starch and the probiotic had a beneficial effect on piglet growth performance and resulted in a reduction of diarrhea and increased microbial diversity in the gut. We conclude that the use of E. coli probiotic strains against E. coli K88 in the presence of raw potato starch is effective in reducing the negative effects of ETEC in a piglet challenge model.

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