Search results for "Biochemical Phenomena"
showing 10 items of 496 documents
Transcriptome analysis revealed that a quorum sensing system regulates the transfer of the pAt megaplasmid in Agrobacterium tumefaciens.
2016
Background Agrobacterium tumefaciens strain P4 is atypical, as the strain is not pathogenic and produces a for this species unusual quorum sensing signal, identified as N-(3-hydroxy-octanoyl)-homoserine lactone (3OH,C8-HSL). Results By sequence analysis and cloning, a functional luxI-like gene, named cinI, has been identified on the At plasmid of A. tumefaciens strain P4. Insertion mutagenesis in the cinI gene and transcriptome analyses permitted the identification of 32 cinI-regulated genes in this strain, most of them encoding proteins responsible for the conjugative transfer of pAtP4. Among these genes were the avhB genes that encode a type 4 secretion system (T4SS) involved in the forma…
Food quality affects the expression of antimicrobial peptide genes upon simulated parasite attack in the larvae of greater wax moth
2017
Predator‐prey interactions are an important evolutionary force affecting the immunity of the prey. Parasitoids and mites pierce the cuticle of their prey, which respond by activating their immune system against predatory attacks. Immunity is a costly function for the organism, as it often competes with other life‐history traits for limited nutrients. We tested whether the expression of antimicrobial peptides (AMP) of the larvae of the greater wax moth Galleria mellonella (L.) (Lepidoptera: Pyralidae) changes as a consequence of insertion of a nylon monofilament, which acts like a synthetic parasite. The treatment was done for larvae grown on a high‐quality vs. a low‐quality diet. The expres…
Preliminary evidence of the horizontal transmission of Wolbachia between Crioceris leaf beetles (Coleoptera: Chrysomelidae) and their Asparagus host …
2017
Intracellular bacteria of the genus Wolbachia (alpha-Proteobacteria) are the most widespread endosymbionts of insects. Host infection is usually associated with alterations in reproduction, such as cytoplasmic incompatibility, the induction of parthenogenesis and offspring sex ratio bias: all phenomena that may influence host speciation. In the present study, by using well-established molecular tools, we investigated the presence of Wolbachia in leaf beetles of the genus Crioceris and their host plants, which are various species of Asparagus. Multilocus sequence typing of bacterial genes showed that despite their occurrence in the same habitat and feeding on the same plant, two species of C…
Seasonal Changes in the Endosymbiotic Consortia of Aphids from the Genus <i>Cinara</i>
2016
Buchnera aphidicola is the primary endosymbiont of aphids with which it maintains an obligate mutualistic symbiotic relationship. Insects also maintain facultative symbiotic relationships with secondary symbionts, and Serratia symbiotica is the most common in aphids. The presence of both symbionts in aphids of the subfamily Lachninae has been widely studied by our group. We examined two closely related aphids, Cinara tujafilina and C. cedri in the present study. Even though both B. aphidicola strains have similar genome sizes and gene contents, the genomes of the two S. symbiotica strains were markedly different. The SCc strain has the smallest genome known for this species, while SCt posse…
Immune-Endocrine Interactions in the Fish Gonad during Infection: An Open Door to Vertical Transmission
2018
The interaction between the immune and endocrine systems has long been recognized in vertebrates. In fish, it is known that the prevalence and intensity of such infections are higher in males than in females and probably related to sex steroid hormone levels. In addition, the immune response in the fish gonad tissues is specifically regulated to prevent infertility. This condition is used by some pathogens to colonize the fish gonad, evade the systemic immune response, and so spread to the progeny. This review brings up to date our knowledge concerning fish gonad immunity and its regulation, immune-endocrine interactions, and how some pathogens use this tissue to spread to the progeny throu…
Prevalence of Extended Spectrum Beta Lactamase Producing Bacteria in Two Surgical Wards of a General Hospital
2019
Abstract Colonisation of gastrointestinal tract by extended spectrum beta lactamase (ESBL)-producing Gram-negative bacteria is a source for infections. The present work is a prospective study in Latvia aimed to determine the role of two surgical profile wards in transmission of ESBL-producing bacteria. Differences between hospital wards were not analysed due to low number of patients. We have also determined a correlation between the duration of hospitalisation and risk of ESBL colonisation. Tests for ESBL-producing bacteria were made twice for 136 patients — upon admission and upon discharge from the hospital. Of them, 21 (15.4%) patients already were ESBL-positive at the time of admission…
Immunization Status against Measles of Health-Care Workers Operating at Three Sicilian University Hospitals: An Observational Study
2019
Measles is a highly contagious vaccine-preventable disease (VPD) that also commonly affects health-care workers (HCWs). Measles immunization of HCWs was strongly recommended by international health authorities, in order to limit the spreading of the illness to susceptible patients and colleagues. An observational study, evaluating the immunization and vaccination status against measles of HCWs working at three Sicilian university hospitals, was conducted. All subjects not completely immune (vaccinated with only one dose in their lifetime), not immune (not vaccinated or not naturally immunized), and with an unknown immunization status were considered not immunized. Among HCWs operating in th…
A new class of phenylhydrazinylidene derivatives as inhibitors of Staphylococcus aureus biofilm formation
2016
In the struggle against the emergence of the antibiotic resistance, new molecules targeting biofilm formation could be useful as adjuvant of conventional antibiotics. This study focused on a new class of 2-phenylhydrazinylidene derivatives as antivirulence agents. The compound 12e showed interesting activities against biofilm formation of all tested Staphylococcus aureus strains with IC50 ranging from 1.7 to 43 µM; compounds 12f and 13a resulted strong inhibitors of S. aureus ATCC 6538 and ATCC 29213 biofilm formation with IC50 of 0.9 and 0.8 µM, respectively. A preliminary study on the mechanism of action was carried on evaluating the inhibition of sortase A transpeptidase. Compound 12e re…
Impact of freeze-thaw cytoablation on aqueous outflow patterns in ex vivo anterior chamber perfusion cultures and whole eyes
2022
Background: Porcine eyes have been widely used as ex vivo models in glaucoma research, as they share similar features with human eyes. Freeze-thawing is a non-invasive technique that has been used to obliterate living cells in anterior segment ex vivo cultures, to prepare them for further research such as cellular repopulation. This technique has previously been shown to reduce the intraocular pressure (IOP) in porcine eyes. The aim of this study was to investigate whether freeze-thaw cytoablation causes corresponding canalogram outflow changes in perfused anterior segment cultures (AFT) and whole porcine eyes (WFT). We hypothesized that the known IOP drop in AFT after trabecular meshwork a…
Immunoistochemical expression of PD-1 and PD-L1 in bone marrow biopsies of patients with acute myeloid leukemia
2020
Background. Haematological and non-haematological malignancies are able to escape the host immune by the capacity to hijack the immune check-points. Several immune check-point molecules are known, such as T cell immunoglobulin mucin-3 (TIM-3), cytotoxic T-cell antigen-4 (CTLA-4), programmed death-1 (PD-1) with its ligand PD-L1 and others.1 The function of these immune check-points is to prevent the damage resulting from an excessive activation of the immune response in the setting of chronic antigenic stimulation, thus leading to autoimmune phenomena, as proved in knock-out mice models. PD-1 is normally present on activated T lymphocytes membrane, acting as a negative costimulatory receptor…