Parathyroid hormone-related peptide (hPTHrP) and parathyroid hormone-related peptide receptor type 1 (PTHR1) expression in human thymus.

Parathyroid hormone-related peptide (hPTHrP) is expressed in human tissues and regulates cellular proliferation, differentiation, and apoptosis by an autocrine/paracrine loop. In rodent thymus, both parathormone and parathyroid hormone-related peptide (PTHrP) are expressed by thymic epithelial cells (TECs). The present study demonstrated by RT-PCR and immunohistochemistry that hPTHrP and parathyroid hormone-related peptide receptor type 1 (PTHR1) were expressed in human thymus at both RNA and protein levels. hPTHrP was expressed mainly in the thymic medulla by epithelial (cytokeratin-positive), mature dendritic (CD40+/86+) and plasmacytoid interleukin (IL)-3Ralpha1 cells. This protein was also present in some cells forming Hassall's bodies and a few subcapsular and cortical TECs. PTHR1 was expressed by scattered subcapsular and cortical TECs and by rare TECs in the medulla. Thymocytes did not express either hPTHrP or PTHR1. Primary cultures of human TECs revealed the presence of both hPTHrP and PTHR1 mRNAs, confirming the capacity of TECs to synthesize both peptides. Moreover, synthetic (1-39) hPTHrP peptide administered on cultured TECs induced the expression of IL-6 mRNA, suggesting that hPTHrP can regulate thymic functions by inducing in TECs the expression of IL-6, which is involved in the development and maturation of thymocytes.     

Genetic Diversity of Giardia duodenalis: Multilocus Genotyping Reveals Zoonotic Potential between Clinical and Environmental Sources in a Metropolitan Region of Brazil

Background

Giardia duodenalis is a flagellate protozoan that parasitizes humans and several other mammals. Protozoan contamination has been regularly documented at important environmental sites, although most of these studies were performed at the species level. There is a lack of studies that correlate environmental contamination and clinical infections in the same region. The aim of this study is to evaluate the genetic diversity of a set of clinical and environmental samples and to use the obtained data to characterize the genetic profile of the distribution of G. duodenalis and the potential for zoonotic transmission in a metropolitan region of Brazil.

Methodology/Principal Findings

The genetic assemblages and subtypes of G. duodenalis isolates obtained from hospitals, a veterinary clinic, a day-care center and important environmental sites were determined via multilocus sequence-based genotyping using three unlinked gene loci. Cysts of Giardia were detected at all of the environmental sites. Mixed assemblages were detected in 25% of the total samples, and an elevated number of haplotypes was identified. The main haplotypes were shared among the groups, and new subtypes were identified at all loci. Ten multilocus genotypes were identified: 7 for assemblage A and 3 for assemblage B.

Conclusions/Significance

There is persistent G. duodenalis contamination at important environmental sites in the city. The identified mixed assemblages likely represent mixed infections, suggesting high endemicity of Giardia in these hosts. Most Giardia isolates obtained in this study displayed zoonotic potential. The high degree of genetic diversity in the isolates obtained from both clinical and environmental samples suggests that multiple sources of infection are likely responsible for the detected contamination events. The finding that many multilocus genotypes (MLGs) and haplotypes are shared by different groups suggests that these sources of infection may be related and indicates that there is a notable risk of human infection caused by Giardia in this region.     

Molecular study of genes involved in virulence regulatory pathways in Bacillus anthracis vaccine strain "Carbosap"

This study investigated the genetic bases of attenuation in the Bacillus anthracis vaccine strain "Carbosap" used in Italy against anthrax in cattle and sheep. Twelve genes involved in virulence regulatory pathways underwent sequence analysis in comparison with a B. anthracis virulent strain.     

Lycopene prevents 7-ketocholesterol-induced oxidative stress,cell cycle arrest and apoptosis in human macrophages

The present study was undertaken to examine whether lycopene is able to counteract 7-ketocholesterol (7-KC)-induced oxidative stress and apoptosis in human macrophages. Human THP-1 macrophages were exposed to 7-KC (10–25 μM) alone and in combination with lycopene (0.5–2 μM), and we monitored changes in cell oxidative status [reactive oxygen species (ROS) production, NOX-4, hsp70 and hsp90 expressions, 8-OHdG formation] and in cell proliferation and apoptosis. After 24 h of treatment, lycopene significantly reduced the increase in ROS production and in 8-OHdG formation induced by the oxysterol in a dose-dependent manner. Moreover, the carotenoid strongly prevented the increase of NOX-4, hsp70 and hsp90 expressions as well as the phosphorylation of the redox-sensitive p38, JNK and ERK1/2 induced by the oxysterol. The attenuation of 7-KC-induced oxidative stress by lycopene coincided with a normalization of cell growth in human macrophages. Lycopene prevented the arrest in G0/G1 phase of cell cycle induced by the oxysterol and counteracted the increased expression of p53 and p21. Concomitantly, it inhibited 7-KC-induced apoptosis, by limiting caspase-3 activation and the modulatory effects of 7-KC on AKT, Bcl-2, Bcl-xL and Bax. Comparing the effects of lycopene, β-carotene and (5Z)-lycopene on ROS production, cell growth and apoptosis show that lycopene and its isomer were more effective than β-carotene in counteracting the dangerous effects of 7-KC in human macrophages. Our study suggests that lycopene may act as a potential antiatherogenic agent by preventing 7-KC-induced oxidative stress and apoptosis in human macrophages.     

Comparative proteomic analysis of Xanthomonas citri ssp. citri periplasmic proteins reveals changes in cellular envelope metabolism during in vitro pathogenicity induction

Citrus canker is a plant disease caused by Gram‐negative bacteria from the genus Xanthomonas. The most virulent species is Xanthomonas citri ssp. citri (XAC), which attacks a wide range of citrus hosts. Differential proteomic analysis of the periplasm‐enriched fraction was performed for XAC cells grown in pathogenicity‐inducing (XAM‐M) and pathogenicity‐non‐inducing (nutrient broth) media using two‐dimensional electrophoresis combined with liquid chromatography‐tandem mass spectrometry. Amongst the 40 proteins identified, transglycosylase was detected in a highly abundant spot in XAC cells grown under inducing condition. Additional up‐regulated proteins related to cellular envelope metabolism included glucose‐1‐phosphate thymidylyltransferase, dTDP‐4‐dehydrorhamnose‐3,5‐epimerase and peptidyl‐prolyl cis–trans‐isomerase. Phosphoglucomutase and superoxide dismutase proteins, known to be involved in pathogenicity in other Xanthomonas species or organisms, were also detected. Western blot and quantitative real‐time polymerase chain reaction analyses for transglycosylase and superoxide dismutase confirmed that these proteins were up‐regulated under inducing condition, consistent with the proteomic results. Multiple spots for the 60‐kDa chaperonin and glyceraldehyde‐3‐phosphate dehydrogenase were identified, suggesting the presence of post‐translational modifications. We propose that substantial alterations in cellular envelope metabolism occur during the XAC infectious process, which are related to several aspects, from defence against reactive oxygen species to exopolysaccharide synthesis. Our results provide new candidates for virulence‐related proteins, whose abundance correlates with the induction of pathogenicity and virulence genes, such as hrpD6, hrpG, hrpB7, hpa1 and hrpX. The results present new potential targets against XAC to be investigated in further functional studies.     

Molecular Cloning of α-Amylases from Cotton Boll Weevil, Anthonomus grandis and Structural Relations to Plant Inhibitors: An Approach to Insect Resistance

Anthonomus grandis, the cotton boll weevil, causes severe cotton crop losses in North and South America. Here we demonstrate the presence of starch in the cotton pollen grains and young ovules that are the main A. grandis food source. We further demonstrate the presence of α-amylase activity, an essential enzyme of carbohydrate metabolism for many crop pests, in A. grandis midgut. Two α-amylase cDNAs from A. grandis larvae were isolated using RT-PCR followed by 5′ and 3′ RACE techniques. These encode proteins with predicted molecular masses of 50.8 and 52.7 kDa, respectively, which share 58% amino acid identity. Expression of both genes is induced upon feeding and concentrated in the midgut of adult insects. Several α-amylase inhibitors from plants were assayed against A. grandis α-amylases but, unexpectedly, only the BIII inhibitor from rye kernels proved highly effective, with inhibitors generally active against other insect amylases lacking effect. Structural modeling of Amylag1 and Amylag2 showed that different factors seem to be responsible for the lack of effect of 0.19 and α-AI1 inhibitors on A. grandis α-amylase activity. This work suggests that genetic engineering of cotton to express α-amylase inhibitors may offer a novel route to A. grandis resistance.     

Evaluation of Corrosion Resistance and Characterization of Ni-Cr Coated Structure Using Plasma Spray Coating for Marine Hulls

Plasmonics - Corrosion is a natural process which gradually destructs the materials with their environment by chemical or electrochemical means. Mechanized boat hull structures used in fishing were...     

Macroalgae and nutrients promote algal turf growth in the absence of herbivores

Coral Reefs - Closely cropped algal turfs are characteristic of healthy coral reefs, but unchecked growth can cause transitions into long sediment-laden turfs, which may be an alternative degraded...