Effects of polyamines on the expression of antioxidant genes and proteins in citrus plants exposed to salt stress

Although there are accumulating reports that polyamines are involved in abiotic/oxidative stress responses, their role is not yet fully understood. Salt stress is one of the most devastating abiotic stresses which seriously interrupt plant growth and productivity. The present study attempts to examine the effects of root treatments with putrescine (Put, I mM), spermidine (Spd, ImM) and spermine (Spm, ImM) on polyamine homeostasis, as well as on several antioxidant-related genes and proteins in the leaves of citrus plants (Citrus aurantium L.) exposed to 150 mM NaCI for 15 d. Analysis of endogenous levels of free polyarnines in NaCl-stressed plant tissues reveals the existence of a polyamine transport system from roots to leaves. Real-time analysis of reactive oxygen species (ROS) by confocal laser scanning microscopy (CLSM) showed an over-accumulation of superoxide anion (02) and hydrogen peroxide (H202) in the stomata of citrus plants exposed to salt stress. Exogenously applied polyamines to salinized nutrient solution induced the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and ascrobic oxidase (AO) whereas it caused the opposite effect on peroxidase (POD), guaiacol peroxidase (GPO D) and ascorbate peroxidase (APX). The effect of polyamines was further examined by determining the plant's antioxidant gene expression profile following a quantitative real-time RT-PCR approach. The overall results indicate that the interaction between different polyamines can be dispersed throughout the citrus plant, and provide additional information suggesting that polyamines may act as a biological mediator allowing citrus plants to activate specific antioxidant responses against salinit

Biomarkers of human gastrointestinal tract regions

Dysregulation of intestinal epithelial cell performance is associated with an array of pathologies whose onset mechanisms are incompletely understood. While whole-genomics approaches have been valuable for studying the molecular basis of several intestinal diseases, a thorough analysis of gene expression along the healthy gastrointestinal tract is still lacking. The aim of this study was to map gene expression in gastrointestinal regions of healthy human adults and to implement a procedure for microarray data analysis that would allow its use as a reference when screening for pathological deviations. We analyzed the gene expression signature of antrum, duodenum, jejunum, ileum, and transverse colon biopsies using a biostatistical method based on a multivariate and univariate approach to identify region-selective genes. One hundred sixty-six genes were found responsible for distinguishing the five regions considered. Nineteen had never been described in the GI tract, including a semaphorin probably implicated in pathogen invasion and six novel genes. Moreover, by crossing these genes with those retrieved from an existing data set of gene expression in the intestine of ulcerative colitis and Crohn's disease patients, we identified genes that might be biomarkers of Crohn's and/or ulcerative colitis in ileum and/or colon. These include CLCA4 and SLC26A2, both implicated in ion transport. This study furnishes the first map of gene expression along the healthy human gastrointestinal tract. Furthermore, the approach implemented here, and validated by retrieving known gene profiles, allowed the identification of promising new leads in both healthy and disease state

The Nasal-associated Lymphoid Tissue of Adult Mice Acts as an Entry Site for the Mouse Mammary Tumor Retrovirus

Mouse mammary tumor virus (MMTV) is a B type retrovirus transmitted to the suckling offspring through milk. MMTV crosses the intestinal barrier of neonates, initially infects the lymphoid cells of the Peyer's patches, and later spreads to all lymphoid organs and to the mammary gland. Adult mice can be infected systemically, but not by oral MMTV administration. In this study, we show that nasal administration of infected milk induces the infection of adult mice. Nasal MMTV infection shared the main features of systemic and neonatal intestinal MMTV infections: deletion of the superantigen (SAg)-reactive T cell subset from the peripheral T cell population, presence of viral DNA in lymphoid cells, and transmission of MMTV from mother to offspring. Viral DNA was restricted to the lungs and nasal-associated lymphoid tissue (NALT) 6 d after nasal infection. Furthermore, SAg-induced T cell proliferation was only detected in NALT. These results demonstrate that MMTV crosses the intact epithelium of the upper respiratory tract of adult mice and infects the lymphoid follicles associated with these structures

Dental Management of Patients with Autism Spectrum Disorders

Dental treatment of patients with Autism Spectrum Disorders (ASD) can be complicated because of the presence of behavioural unpredictability. This article reviews the present literature on the issues dealt with children with autistic spectrum disorder from the dental perspective. The prevalence of autism is rising worldwide. Consequently, dentists will find an increasing number of such children in their routine practice, whose treatment will require special considerations in their dental management. Knowledge regarding the oral health status of autistic children is essential for the paediatric dentists. Negative behaviour toward dental treatment was very clear in autistic children. Self-inflicting trauma/habits were observed in autistic children. It was concluded that the autistic children do not have a higher dental caries score compared to that of normal children. Their oral hygiene was fair; however, they exhibited more debris deposits than normal children

Systemic Antibodies Can Inhibit Mouse Mammary Tumor Virus-Driven Superantigen Response in Mucosa-Associated Lymphoid Tissues

Many mucosal pathogens invade the host by initially infecting the organized mucosa-associated lymphoid tissue (o-MALT) such as Peyer’s patches or nasal cavity-associated lymphoid tissue (NALT) before spreading systemically. There is no clear demonstration that serum antibodies can prevent infections in o-MALT. We have tested this possibility by using the mouse mammary tumor virus (MMTV) as a model system. In peripheral lymph nodes or in Peyer’s patches or NALT, MMTV initially infects B lymphocytes, which as a consequence express a superantigen (SAg) activity. The SAg molecule induces the local activation of a subset of T cells within 6 days after MMTV infection. We report that similar levels of anti-SAg antibody (immunoglobulin G) in serum were potent inhibitors of the SAg-induced T-cell response both in peripheral lymph nodes and in Peyer’s patches or NALT. This result clearly demonstrates that systemic antibodies can gain access to Peyer’s patches or NALT

Polyamines modify the nitrosative status of salt stressed plants

Although there is accumulating evidence that polyamines are involved in the response of plants to both salinity and nitrosative stress, their role is not yet fully understood. The present study attempts to examine the effects of hydroponic root treatments with putrescine (Put, 1 mM), spermidine (Spd, 1mM) and spermine (Spm, 1mM) on nitrosative homeostasis in leaves of citrus plants (Citrus aurantium L.) exposed to 100 mM NaCI for 15 d. Nitric oxide (NO) steady-state levels and DAF-2DA-derived fluorescence were stimulated by NaCI treatment and especially by the application of polyamines in the salt-treated plants. Transcriptional analysis showed that the expression of several genes encoding proteins associated with NO biosynthesis, including AOX, XO, GSNO, NOS, NiR and NR, is regulated by polyamine application. In addition, S-nitrosoglutathione reductase (GSNOR) activity was suppressed in plants treated with Put and Spd. The profile of tyrosine-nitrated proteins was diminished by the application of polyamines. The characterization of nitroproteome by mass fingerprinting revealed several protein targets which are involved mainly in photosynthesis, disease/defense, energy and protein destination/storage. These data strongly support a function of polyamines in modulating the nitrosative status upon salt stress