Search results for "microbial"

"Role of Arbuscular Mycorrhizal Fungi in Nutrient Uptake and Growth of Durum Wheat"

Soil microbiome is involved at different levels in the food web, in bio-geochemical nutrient cycles and in several interactions with plants. Based on its key role in the agro-ecosystem processes, the soil microbiome has been identified as one of the principal factors in an agriculture addressed to the ecological intensification. Among the several relationships established between plants and soil microorganisms, arbuscular mycorrhizal (AM) symbiosis is the most widespread. Two out of three of all plant taxa (among others the main crops) are involved in the AM symbiosis which takes place between the plant root system and arbuscular mycorrhizal fungi (AMF), a monophyletic group of fungi belong…

Sulfur isotope's signal of nanopyrites enclosed in 2.7 Ga stromatolitic organic remains reveal microbial sulfate reduction.

2018

18 pages; International audience; Microbial sulfate reduction (MSR) is thought to have operated very early on Earth and is often invoked to explain the occurrence of sedimentary sulfides in the rock record. Sedimentary sulfides can also form from sulfides produced abiotically during late diagenesis or metamorphism. As both biotic and abiotic processes contribute to the bulk of sedimentary sulfides, tracing back the original microbial signature from the earliest Earth record is challenging. We present in situ sulfur isotope data from nanopyrites occurring in carbonaceous remains lining the domical shape of stromatolite knobs of the 2.7-Gyr-old Tumbiana Formation (Western Australia). The anal…

Marine organisms as source of bioactive molecules applied in restoration projects

2015

Abstract In recent decades research in the conservation and restoration field has provided sustainable alternatives to traditional procedures for cleaning or controlling the microbial colonization of works of art. In the present study, for the first time novel bioactive molecules extracted from marine invertebrate organisms (Anthozoa) were tested instead of chemical compounds for removing protein layers or as a biocide for controlling fungal or bacterial colonization. In particular, Bioactive Molecules with Protease activity (BMP), acting in a temperature range of 4- 30°C, were tested for the hydrolysis of protein layers on laboratory specimens. The cleaning protocol provides a selective pr…

Antibacterial and antifungal activities of Otanthus maritimus (L.) Hoffmanns.Link essential oil from Sicily.

2013

The chemical composition of the essential oil obtained from the flowers of Otanthus maritimus L., a perennial plant growing wild in maritime sands in the Mediterranean region, was investigated by GC and GC-MS analyses. Totally 66 were identified. The oil was dominated by the high content of monoterpene compounds, especially oxygenated monoterpenes which accounted for 73.1%. The most abundant components were yomogi alcohol (20.8%), camphor (15.8%), artemisyl acetate (15.3%) and artemisia alcohol (13.7%). The oil was tested against two Gram (+) and six Gram (-) bacterial strains, both American Type Culture Collection standard strains and clinically isolated (CI), one potentially pathogenic ye…

Artificial Neural Networks and Linear Discriminant Analysis:  A Valuable Combination in the Selection of New Antibacterial Compounds

2004

A set of topological descriptors has been used to discriminate between antibacterial and nonantibacterial drugs. Topological descriptors are simple integers calculated from the molecular structure represented in SMILES format. The methods used for antibacterial activity discrimination were linear discriminant analysis (LDA) and artificial neural networks of a multilayer perceptron (MLP) type. The following plot frequency distribution diagrams were used: a function of the number of drugs within a value interval of the discriminant function and the output value of the neural network versus these values. Pharmacological distribution diagrams (PDD) were used as a visualizing technique for the i…

Crowdsourced analysis of fungal growth and branching on microfluidic platforms

2021

Fungal hyphal growth and branching are essential traits that allow fungi to spread and proliferate in many environments. This sustained growth is essential for a myriad of applications in health, agriculture, and industry. However, comparisons between different fungi are difficult in the absence of standardized metrics. Here, we used a microfluidic device featuring four different maze patterns to compare the growth velocity and branching frequency of fourteen filamentous fungi. These measurements result from the collective work of several labs in the form of a competition named the “Fungus Olympics.” The competing fungi included five ascomycete species (ten strains total), two basidiomycete…

Cytotoxic labdane diterpenes and bisflavonoid atropisomers from leaves of Araucaria bidwillii

2017

Abstract Chemical investigation of a methanolic extract of leaves from Araucaria bidwillii (Araucariaceae) from Egypt afforded four new labdane diterpenoidal metabolites (1–4) together with one known diterpene, 7-oxocallitrisic acid (5), two triterpenoidal metabolites, 2-O-acetyl-11-keto-boswellic acid (6) and β-sitosterol-3-O-glucopyranoside (7), phloretic acid (8), and two methylated bisflavonoids, agathisflavone-4′,7,7″-trimethyl ether (9) and cupressuflavone-4′,7,7″-trimethyl ether (10). The new metabolites 1–4 were unambiguously identified by applying extensive 1D and 2D NMR spectroscopic studies as well as HRESIMS. The relative and absolute configurations of 1–4 were determined using …

A combined experimental and theoretical study of the thermal cycloaddition of aryl azides with activated alkenes.

2011

International audience; Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the β-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower acti…

Application of propidium monoazide-qPCR to evaluate the ultrasonic inactivation of Escherichia coli O157:H7 in fresh-cut vegetable wash water.

2012

The efficacy of sanitizing technologies in produce or in vegetable wash water is generally evaluated by plate count in selective media. This procedure is time consuming and can lead to misinterpretations because environmental conditions and sanitizing processes may affect bacterial growth or culturable capability. Thus, the aim of this study was to determine the applicability of a propidium monoazide real-time PCR (PMA-qPCR) method to monitor the inactivation by ultrasound treatment of foodborne bacteria in fresh-cut vegetable wash water. To this aim, lettuce wash water was artificially inoculated with Escherichia coli O157:H7 (10⁶ CFU/mL) and treated by means of a continuous ultrasonic irr…

Application of viability PCR to discriminate the infectivity of hepatitis A virus in food samples.

2015

Abstract Transmitted through the fecal–oral route, the hepatitis A virus (HAV) is acquired primarily through close personal contact and foodborne transmission. HAV detection in food is mainly carried out by quantitative RT-PCR (RT-qPCR). The discrimination of infectious and inactivated viruses remains a key obstacle when using RT-qPCR to quantify enteric viruses in food samples. Initially, viability dyes, propidium monoazide (PMA) and ethidium monoazide (EMA), were evaluated for the detection and quantification of infectious HAV in lettuce wash water. Results showed that PMA combined with 0.5% Triton X-100 (Triton) was the best pretreatment to assess HAV infectivity and completely eliminate…