Search results for "COLONIZATION"
showing 10 items of 201 documents
Soil and fertilizer phosphorus : effects on plant P supply and mycorrhizal development
2005
Plants require adequate P from the very early stages of growth for optimum crop production. Phosphorus supply to the crop is affected by soil P, P fertilizer management and by soil and environmental conditions influencing P phytoavailability and root growth. Phosphorus uptake in many crops is improved by associations with arbuscular mycorrhizal fungi. Cropping system and long-term input of P through fertilizers and manures can influence the amount and phytoavailability of P in the system and the development of mycorrhizal associations. Optimum yield potential requires an adequate P supply to the crop from the soil or from P additions. Where early-season P supply is low, P fertilization may…
Arbuscular mycorrhizal fungi in Georgia, the Caucasus region: the first report of species diversity and root colonization
2018
Although the Caucasus region belongs to the world biodiversity hotspots, arbuscular mycorrhizal fungi (AMF) have not been investigated in this area. A total of 11 mixtures of soils and roots from 11 localities in southern Georgia in an altitudinal gradient from 1 to 1560 m a. s. l. were sampled in 2015. AMF spores and arbuscular mycorrhiza were observed in all samples. Eight AMF species were found in the field-collected soils: Acaulospora bireticulata, Acaulospora cavernata, Funneliformis coronatum, Gigaspora gigantea, Glomus rubiforme, Scutellospora dipurpurescens, Septoglomus constrictum, and Septoglomus jasnowskae. The most frequently occurring species proved to be S. constrictum. Labora…
Cell interactions between a nonpathogenic Fusarium oxysporum strain and root tissues of Eucalyptus viminalis
2004
Nonpathogenic isolates of Fusarium oxysporum can be successful antagonists of pathogenic forms of the same fungal species that commonly attacks crop plants. The characteristics that distinguish nonpathogenic from pathogenic forms are not well understood. In this study, the mode of root colonization of Eucalyptus viminalis seedlings by a nonpathogenic F. oxysporum strain is described at the ultrastructural level. Root systems of E. viminalis plants were inoculated with nonpathogenic F. oxysporum strain Fo47 in an in vitro model system. Changes in the occurrence of nonesterified and methyl-esterified pectins in colonized E. viminalis roots were evaluated by in situ immunolabeling using two mo…
Influence of plant traits, soil microbial properties, and abiotic parameters on nitrogen turnover of grassland ecosystems
2016
International audience; Although it is known that multiple interactions among plant functional traits, microbial properties , and abiotic soil parameters influence the nutrient turnover, the relative contribution of each of these groups of variables is poorly understood. We manipulated grassland plant functional composition and soil nitrogen (N) availability in a multisite mesocosm experiment to quantify their relative effects on soil N turnover. Overall, root traits, arbuscular mycorrhizal colonization, denitrification potential, as well as N availability and water availability, best explained the variation in measured ecosystem properties, especially the trade-off between nutrient sequest…
Birth Mode-Related Differences in Gut Microbiota Colonization and Immune System Development.
2018
<b><i>Background:</i></b> The process of early gut colonization is extremely variable among individuals and is influenced by numerous factors. Among these, the mode of birth will strongly shape the early microbial exposure and immune environment of the neonate. <b><i>Summary:</i></b> Here, I review how the concomitant processes of microbiota and immune system development are altered by C-section delivery and the effects of such alterations on long-term health. <b><i>Key messages:</i></b> C-section delivery impinges on microbiota and immune system development through various means: (i) if labor is lacking, intrauterine i…
Antibacterial properties and reduction of MRSA biofilm with a dressing combining polyabsorbent fibres and a silver matrix
2016
Objective: This study was designed to evaluate the antibacterial activity of a wound dressing which combines polyacrylate fibres and a silver lipido-colloid matrix (UrgoClean Ag, silver polyabsorbent dressing), against biofilm of methicillin-resistant Staphylococcus aureus (MRSA). Method: Samples of silver polyabsorbent dressing and the neutral form of this dressing (UrgoClean) were applied to biofilms of MRSA formed on a collagen I-coated surface, cultured for 24 hours. Different exposure times were tested (1, 2, 4 and 7 days) without dressing change. The biofilm reduction was quantified by using culture methods and by confocal laser scanning microscopy experiments. Results: The applicatio…
Disentangling the effect of host genetics and gut microbiota on resistance to an intestinal parasite
2019
11 pages; International audience; Resistance to infection is a multifactorial trait, and recent work has suggested that the gut microbiota can also contribute to resistance. Here, we performed a fecal microbiota transplant to disentangle the contribution of the gut microbiota and host genetics as drivers of resistance to the intestinal nematode Heligmosomoides polygyrus. We transplanted the microbiota of a strain of mice (SJL), resistant to H. polygyrus, into a susceptible strain (CBA) and vice-versa. We predicted that if the microbiota shapes resistance to H. polygyrus, the FMT should reverse the pattern of resistance between the two host strains. The two host strains had different microbi…
Suppression of Saprolegnia infections in rainbow trout (Oncorhynchus mykiss) eggs using protective bacteria and ultraviolet irradiation of the hatche…
2014
Since formalin is widely used in prevention of Sapro- legnia infections in salmonid fish hatcheries, there is a need for more environmentally safe treatment methods. Therefore, we screened 360 bacterial iso- lates against their ability to antagonize the growth of Saprolegnia parasitica hyphae in vitro, and best strains were selected according to their antagonistic proper- ties and colonization capability on rainbow trout egg surface. Protective bacterial cultures of Pseudomonas sp. M162, Pseudomonas sp. M174 and Janthinobacte- rium M169 were tested for prevention of Saprolegnia sp. infections during incubation trials of rainbow trout (Oncorhynchus mykiss )e ggs with UV irradiated (400 mWs c…
Host and environmental factors affecting the intestinal microbiota in chickens
2018
The initial development of intestinal microbiota in poultry plays an important role in production performance, overall health and resistance against microbial infections. Multiplexed sequencing of 16S ribosomal RNA gene amplicons is often used in studies, such as feed intervention or antimicrobial drug trials, to determine corresponding effects on the composition of intestinal microbiota. However, considerable variation of intestinal microbiota composition has been observed both within and across studies. Such variation may in part be attributed to technical factors, such as sampling procedures, sample storage, DNA extraction, the choice of PCR primers and corresponding region to be sequenc…
Invasive candida infections in neonates after major surgery: Current evidence and new directions
2021
Infections represent a serious health problem in neonates. Invasive Candida infections (ICIs) are still a leading cause of mortality and morbidity in neonatal intensive care units (NICUs). Infants hospitalized in NICUs are at high risk of ICIs, because of several risk factors: broad spectrum antibiotic treatments, central catheters and other invasive devices, fungal colonization, and impaired immune responses. In this review we summarize 19 published studies which provide the prevalence of previous surgery in neonates with invasive Candida infections. We also provide an overview of risk factors for ICIs after major surgery, fungal colonization, and innate defense mechanisms against fungi, a…