110 research outputs found
Arbuscular Mycorrhizal Fungal Communities of Native Plant Species under High Petroleum Hydrocarbon Contamination Highlights Rhizophagus as a Key Tolerant Genus.
Arbuscular mycorrhizal fungi (AMF) have been shown to play an important role in increasing plant fitness in harsh conditions. Therefore, AMF are currently considered to be effective partners in phytoremediation. However, AMF communities in high levels of petroleum pollution are still poorly studied. We investigated the community structures of AMF in roots and rhizospheric soils of two plant species, Eleocharis elliptica and Populus tremuloides, growing spontaneously in high petroleum-contaminated sedimentation basins of a former petrochemical plant (91,000 ÎŒg/Kg of C10-C50 was recorded in a basin which is 26-fold higher than the threshold of polluted soil in Quebec, Canada). We used a PCR cloning, and sequencing approach, targeting the 18S rRNA gene to identify AMF taxa. The high concentration of petroleum-contamination largely influenced the AMF diversity, which resulted in less than five AMF operational taxonomical units (OTUs) per individual plant at all sites. The OTUs detected belong mainly to the Glomerales, with some from the Diversisporales and Paraglomerales, which were previously reported in high concentrations of metal contamination. Interestingly, we found a strong phylogenetic signal in OTU associations with host plant species identity, biotopes (roots or soils), and contamination concentrations (lowest, intermediate and highest). The genus Rhizophagus was the most dominant taxon representing 74.4% of all sequences analyzed in this study and showed clear association with the highest contamination level. The clear association of Rhizophagus with high contamination levels suggests the importance of the genus for the use of AMF in bioremediation, as well as for the survey of key AMF genes related to petroleum hydrocarbon resistance. By favoring plant fitness and mediating its soil microbial interactions, Rhizophagus spp. could enhance petroleum hydrocarbon pollutant degradation by both plants and their microbiota in contaminated sites
Pola Resistensi Bakteri Terhadap Antibiotik Pada Penderita Ulkus Diabetikum Di RSUP Dr. Soeradji Tirtonegoro Klaten Periode September 2014-Agustus 2015
Diabetic foot ulcer is characterized by open foot wounds in diabetic
patients. If the infection is not properly treated the severity of infection will
increase. A potent antibiotic against microorganism is needed for treating the
infection. Increasing the use of antibiotics will have an impact on the development
of bacterial resistance to antibiotics. The aim of this study was to determine the
antibiotic resistance pattern of bacteria in patients with diabetic foot ulcer at X
Hospital during September 2014-August 2015.
This study was non experimental study with descriptive analytic method.
This study with a retrospective design involved data collection from patient
medical records, bacteria culture results, and antibiotic susceptibility testing
results. The data were analyzed to determine the most bacteria to cause infection,
the antibiotic resistance pattern of bacteria, and the appropriate use of antibiotic
based on bacteria culture results and antibiotic susceptibility testing results.
A total of 25 pathogens from 45 patients with diabetic foot ulcer were
identified. Enterococcus sp. was the most bacteria found on infected foot wounds
in diabetic patients 11 (13,4%), followed by Klebsiella sp. 9 (11,0%), and
Staphylococcus aureus 8 (9,8%). Enterococcus sp. was resistant to meropenem
(64%), amikacin (91%), ceftriaxon (82%), and cefixime (91%), then Klebsiella sp.
and Staphylococcus aureus was resistant to ampicillin (100% and 67%). A total of
31,3% definitive antibiotics given to diabetic foot ulcer patients were appropriate
with culture results and antibiotic susceptibility testing result.
Keywords: Resistance pattern, diabetic foot ulcer, antibioti
Paraplégie compliquant une plaie abdominale antérieure par arme blanche
Les traumatismes médullaires sont des complications rares des plaies abdominales antérieures par arme blanche. Son diagnostic est difficile parfoisretardé. L'imagerie par résonance magnétique reste l'examen de choix. Le traitement dépend du tableau clinique et de la gravité de la souffrance médullaire. Le pronostic est corrélé à l'étendue et à la nature de la lésion médullaire. Nous rapportons un cas exceptionnel d'un traumatisme médullaire chez une patiente victime d'une plaie abdominale antérieure par arme blanche
Allelic differences within and among sister spores of the arbuscular mycorrhizal fungus Glomus etunicatum suggest segregation at sporulation
Arbuscular mycorrhizal fungi (AMF) are root-inhabiting fungi that form mutualistic symbioses with their host plants. AMF are made up of coenocytic networks of hyphae through which nuclei and organelles can freely migrate. In this study, we investigated the possibility of a genetic bottleneck and segregation of allelic variation at sporulation for a low-copy Polymerase1-like gene, PLS. Specifically, our objectives were (1) to estimate what allelic diversity is passed on to a single spore (2) to determine whether this diversity is less than the total amount of variation found in all spores (3) to investigate whether there is any differential segregation of allelic variation. We inoculated three tomato plants with a single spore of Glomus etunicatum each and after six months sampled between two and three daughter spores per tomato plant. Pyrosequencing PLS amplicons in eight spores revealed high levels of allelic diversity; between 43 and 152 alleles per spore. We corroborated the spore pyrosequencing results with Sanger- and pyrosequenced allele distributions from the original parent isolate. Both sequencing methods retrieved the most abundant alleles from the offspring spore allele distributions. Our results indicate that individual spores contain only a subset of the total allelic variation from the pooled spores and parent isolate. Patterns of allele diversity between spores suggest the possibility for segregation of PLS alleles among spores. We conclude that a genetic bottleneck could potentially occur during sporulation in AMF, with resulting differences in genetic variation among sister spores. We suggest that the effects of this bottleneck may be countered by anastomosis (hyphal fusion) between related hyphae
Correction: Spore development and nuclear inheritance in arbuscular mycorrhizal fungi
<p>Abstract</p> <p>Background</p> <p>A conventional tenet of classical genetics is that progeny inherit half their genome from each parent in sexual reproduction instead of the complete genome transferred to each daughter during asexual reproduction. The transmission of hereditary characteristics from parents to their offspring is therefore predictable, although several exceptions are known. Heredity in microorganisms, however, can be very complex, and even unknown as is the case for coenocytic organisms such as Arbuscular Mycorrhizal Fungi (AMF). This group of fungi are plant-root symbionts, ubiquitous in most ecosystems, which reproduce asexually via multinucleate spores for which sexuality has not yet been observed.</p> <p>Results</p> <p>We examined the number of nuclei per spore of four AMF taxa using high Z-resolution live confocal microscopy and found that the number of nuclei was correlated with spore diameter. We show that AMF have the ability, through the establishment of new symbioses, to pass hundreds of nuclei to subsequent generations of multinucleated spores. More importantly, we observed surprising heterogeneity in the number of nuclei among sister spores and show that massive nuclear migration and mitosis are the mechanisms by which AMF spores are formed. We followed spore development of <it>Glomus irregulare </it>from hyphal swelling to spore maturity and found that the spores reached mature size within 30 to 60 days, and that the number of nuclei per spores increased over time.</p> <p>Conclusions</p> <p>We conclude that the spores used for dispersal of AMF contain nuclei with two origins, those that migrate into the spore and those that arise by mitosis in the spore. Therefore, these spores do not represent a stage in the life cycle with a single nucleus, raising the possibility that AMF, unlike all other known eukaryotic organisms, lack the genetic bottleneck of a single-nucleus stage.</p
Les entĂ©robactĂ©ries sĂ©crĂ©trices de bĂ©ta-Lactamases Ă spectre Ă©tendu en urologie Ă lâHĂŽpital Ibn Sina de Rabat
LâantibiorĂ©sistance croissante des bactĂ©ries responsables des infections urinaires limite le choix des antibiotiques en chirurgie urologique. Parmi ces germes sont retrouvĂ©es les entĂ©robactĂ©ries productrices de bĂ©talactamases Ă spectre Ă©largi (EBLSE) dont la progression devient inquiĂ©tante. Lâobjectif de cette Ă©tude Ă©tait de dĂ©terminer la prĂ©valence des entĂ©robactĂ©ries sĂ©crĂ©trices de BLSE dans les prĂ©lĂšvements dâurines en pĂ©ri opĂ©ratoire de chirurgie urologique. Il sâagissait dâune Ă©tude rĂ©trospective rĂ©alisĂ©e au centre hospitalier universitaire Ibn Sina de Rabat sur une pĂ©riode de 19 mois. Nâont pas Ă©tĂ© inclus dans cette Ă©tude, les prĂ©lĂšvements urinaires rĂ©alisĂ©s Ă dans un laboratoire externe. Les donnĂ©es Ă©taient traitĂ©es avec le logiciel SPSS, les comparaisons faites par test du Khi deux ou de Student avec un seuil de risque alpha fixĂ© Ă 5%. Sur 830 prĂ©lĂšvements positifs 656 Ă©taient des entĂ©robactĂ©ries soit 79 % des germes isolĂ©s. E.coli reprĂ©sentait 53,2%, K.pneumoniae 28%, E.cloacae 7,8% et P.mirabillis 7%. Les producteurs de BLSE reprĂ©sentaient 17,5% de lâĂ©chantillon avec: E.coli (12,3%), K.pneumoniae (23,6%), E.cloacae (39,2%) et P.mirabillis (6,7%). On note une augmentation de la prĂ©valence des entĂ©robactĂ©ries BLSE entre 2008 et 2009 : respectivement de 14,4% Ă 22,3% des entĂ©robactĂ©ries isolĂ©es; pour E.coli de 32,76% Ă 40,68% et pour K.pneumoniae de 34,48% Ă 42,37%. Plusieurs facteurs de risque dâacquisition des EBLSE sont rapportĂ©s dans la littĂ©rature, dont principalement lâutilisation antĂ©rieure dâantibiotiques par ces patients. Une politique de gestion rationnelle des antibiotiques en ambulatoire et au sein des Ă©tablissements de santĂ© contribuera Ă une rĂ©duction de lâĂ©mergence des germes rĂ©sistant
Epiparasitic plants specialized on arbuscular mycorrhizal fungi
Over 400 non-photosynthetic species from 10 families of vascular plants obtain their carbon from fungi and are thus defined as myco-heterotrophs. Many of these plants are epiparasitic on green plants from which they obtain carbon by 'cheating' shared mycorrhizal fungi. Epiparasitic plants examined to date depend on ectomycorrhizal fungi for carbon transfer and exhibit exceptional specificity for these fungi, but for most myco-heterotrophs neither the identity of the fungi nor the sources of their carbon are known. Because many myco-heterotrophs grow in forests dominated by plants associated with arbuscular mycorrhizal fungi (AMF; phylum Glomeromycota), we proposed that epiparasitism would occur also between plants linked by AMF. On a global scale AMF form the most widespread mycorrhizae, thus the ability of plants to cheat this symbiosis would be highly significant. We analysed mycorrhizae from three populations of Arachnitis uniflora (Corsiaceae, Monocotyledonae), five Voyria species and one Voyriella species (Gentianaceae, Dicotyledonae), and neighbouring green plants. Here we show that non-photosynthetic plants associate with AMF and can display the characteristic specificity of epiparasites. This suggests that AMF mediate significant inter-plant carbon transfer in nature
Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity
In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity
Contrasting arbuscular mycorrhizal responses of vascular and non-vascular plants to a simulated Palaeozoic CO2 decline
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