Search results for "Bacteria"
showing 10 items of 4919 documents
Does catchment geodiversity foster stream biodiversity?
2019
Abstract Context One approach to maintain the resilience of biotic communities is to protect the variability of abiotic characteristics of Earth’s surface, i.e. geodiversity. In terrestrial environments, the relationship between geodiversity and biodiversity is well recognized. In streams, the abiotic properties of upstream catchments influence stream communities, but the relationships between catchment geodiversity and aquatic biodiversity have not been previously tested. Objectives The aim was to compare the effects of local environmental and catchment variables on stream biodiversity. We specifically explored the usefulness of catchment geodiversity in explaining the species richness on …
No exception to the rule: Candidatus Portiera aleyrodidarum cell wall revisited
2014
International audience; Many insect endosymbionts described so far are gram-negative bacteria. Primary endosymbionts are obligatory bacteria usually harboured by insects inside vacuoles in specialized cells called bacteriocytes. This combination produces a typical three-membrane system with one membrane derived from the insect vacuole and the other two from the bacterial gram-negative cell envelope, composed by the cell wall (the outer membrane plus the periplasmic space) and the plasma membrane (the inner membrane). For the last 21 years, the primary endosymbiont of whiteflies 'Candidatus Portiera aleyrodidarum' was considered an exception to this rule. Previous works stated that only two …
Antibiotics accelerate growth at the expense of immunity
2021
Antibiotics have long been used in the raising of animals for agricultural, industrial or laboratory use. The use of subtherapeutic doses in diets of terrestrial and aquatic animals to promote growth is common and highly debated. Despite their vast application in animal husbandry, knowledge about the mechanisms behind growth promotion is minimal, particularly at the molecular level. Evidence from evolutionary research shows that immunocompetence is resource-limited, and hence expected to trade off with other resource-demanding processes, such as growth. Here, we ask if accelerated growth caused by antibiotics can be explained by genome-wide trade-offs between growth and costly immunocompete…
Genome reduction and potential metabolic complementation of the dual endosymbionts in the whitefly Bemisia tabaci
2015
Background The whitefly Bemisia tabaci is an important agricultural pest with global distribution. This phloem-sap feeder harbors a primary symbiont, “Candidatus Portiera aleyrodidarum”, which compensates for the deficient nutritional composition of its food sources, and a variety of secondary symbionts. Interestingly, all of these secondary symbionts are found in co-localization with the primary symbiont within the same bacteriocytes, which should favor the evolution of strong interactions between symbionts. Results In this paper, we analyzed the genome sequences of the primary symbiont Portiera and of the secondary symbiont Hamiltonella in the B. tabaci Mediterranean (MED) species in orde…
Improvement of Raw Milk Cheese Hygiene through the Selection of Starter and Non-Starter Lactic Acid Bacteria: The Successful Case of PDO Pecorino Sic…
2021
This review article focuses on the technological aspects and microbiological critical points of pressed-cooked cheeses processed from raw ewe’s milk without the inoculation of starter cultures, in particular “Pecorino” cheese typology produced in Italy. After showing the composition of the biofilms adhering to the surface of the traditional dairy equipment (mainly wooden vat used to collect milk) and the microbiological characteristics of PDO Pecorino Siciliano cheese manufactured throughout Sicily, this cheese is taken as a case study to develop a strategy to improve its hygienic and safety characteristics. Basically, the natural lactic acid bacterial populations of fresh and ripened chees…
Hyperbaric Storage of Fruit Juice and Impact on Composition
2018
International audience; One of the main parameters affecting fruit juice preservation is the temperature over storage. Spoilage is further delayed by reducing the temperature, which although valuable, leads to high energy costs. Recently, hyperbaric storage has appeared as an alternative preservation methodology by a microbial growth inhibition similarly to refrigeration storage, showing great potential for energy savings, as well as carbon footprint reduction, as it could be applied at room temperature. Recent publications revealed the possibility to preserve fruit juice under pressure at variable/uncontrolled room temperature, meaning that energy is only required in the compression/decomp…
Effects of Bacillus thuringiensis δ-Endotoxins on the Pea Aphid ( Acyrthosiphon pisum )
2009
ABSTRACT Four Bacillus thuringiensis δ-endotoxins, Cry3A, Cry4Aa, Cry11Aa, and Cyt1Aa, were found to exhibit low to moderate toxicity on the pea aphid, Acyrthosiphon pisum , in terms both of mortality and growth rate. Cry1Ab was essentially nontoxic except at high rates. To demonstrate these effects, we had to use exhaustive buffer-based controls.
Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella
2019
[EN] Two outdoor photobioreactors were operated to evaluate the effect of variable ambient temperature on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella. Four experiments were carried out in different seasons, maintaining the temperature-controlled PBR at around 25¿°C (by either heating or cooling), while the temperature in the non-temperature-controlled PBR was allowed to vary with the ambient conditions. Temperatures in the range of 15¿30¿°C had no significant effect on the microalgae cultivation performance. However, when the temperature rose to 30¿35¿°C microalgae viability was significantly reduced. Sudden temperature rises triggered AOB growth in the indig…
Priming: getting ready for battle
2006
International audience; Infection of plants by necrotizing pathogens or colonization of plant roots with certain beneficial microbes causes the induction of a unique physiological state called “priming.” The primed state can also be induced by treatment of plants with various natural and synthetic compounds. Primed plants display either faster, stronger, or both activation of the various cellular defense responses that are induced following attack by either pathogens or insects or in response to abiotic stress. Although the phenomenon has been known for decades, most progress in our understanding of priming has been made over the past few years. Here, we summarize the current knowledge of p…
Potential Effects of Essential Oils Extracted from Mediterranean Aromatic Plants on Target Weeds and Soil Microorganisms
2020
Essential oils (EOs), extracted from aromatic plants, have been proposed as candidates to develop natural herbicides. This study aimed to evaluate the herbicidal potential of Thymbra capitata (L.) Cav., Mentha ×