Tomato Rab11a characterization evidenced a difference between SYP121-dependent and SYP122-dependent exocytosis

The regulatory functions of Rab proteins in membrane trafficking lie in their ability to perform as molecular switches that oscillate between a GTP- and a GDP-bound conformation. The role of tomato LeRab11a in secretion was analyzed in tobacco protoplasts. Green fluorescent protein (GFP)/red fluorescent protein (RFP)-tagged LeRab11a was localized at the trans-Golgi network (TGN) in vivo. Two serines in the GTP-binding site of the protein were mutagenized, giving rise to the three mutants Rab11S22N, Rab11S27N and Rab11S22/27N. The double mutation reduced secretion of a marker protein, secRGUS (secreted rat beta-glucuronidase), by half, whereas each of the single mutations alone had a much smaller effect, showing that both serines have to be mutated to obtain a dominant negative effect on LeRab11a function. The dominant negative mutant was used to determine whether Rab11 is involved in the pathway(s) regulated by the plasma membrane syntaxins SYP121 and SYP122. Co-expression of either of these GFP-tagged syntaxins with the dominant negative Rab11S22/27N mutant led to the appearance of endosomes, but co-expression of GFP-tagged SYP122 also labeled the endoplasmic reticulum and dotted structures. However, co-expression of Rab11S22/27N with SYP121 dominant negative mutants decreased secretion of secRGUS further compared with the expression of Rab11S22/27N alone, whereas co-expression of Rab11S22/27N with SYP122 had no synergistic effect. With the same essay, the difference between SYP121- and SYP122-dependent secretion was then evidenced. The results suggest that Rab11 regulates anterograde transport from the TGN to the plasma membrane and strongly implicate SYP122, rather than SYP121. The differential effect of LeRab11a supports the possibility that SYP121 and SYP122 drive independent secretory events.     

1H NMR-visible mobile lipid domains correlate with cytoplasmic lipid bodies in apoptotic T-lymphoblastoid cells

The presence of nuclear magnetic resonance (NMR)-visible mobile lipid (ML) domains in apoptotic lymphoblasts suggests alterations in neutral lipid metabolism and compartmentation during programmed cell death. The detection of similar ML signals in activated lymphocytes raises questions about common mechanisms of ML formation during apoptosis and upon lymphoblast stimulation. Structure and subcellular localization of ML domains were therefore investigated by NMR, fluorescence and electron microscopy in Jurkat T-lymphoblasts either induced to apoptosis (by anthracyclines or dexamethasone or by serum deprivation) or activated by phorbol myristate acetate (PMA) plus ionomycin. ML contents in drug-treated cells correlated linearly with apoptosis, irrespective of the specific inducer and cell cycle arrest phase (r=0.993, P<0.001). Similar ML levels were measured in drug-induced apoptotic cells (A≈30–40%) and in non-apoptotic PMA/ionomycin-treated lymphoblasts (72 h). Lower ML contents were instead formed in serum-deprived apoptotic cells, with respect to controls. Increases in ML signals were associated, in either apoptotic or activated cells, with the accumulation of cytoplasmic, osmophilic lipid bodies (diameter≤1.0 μm), surrounded by own membrane, possessing intramembrane particles. The results support the hypothesis that ML are formed in the cytoplasm of drug-induced apoptotic cells during an early, ‘biochemically active’ phase of programmed cell death.     

Association between HMGB1 and asthma: a literature review

Background

Recently, some studies demonstrated that HMGB1, as proinflammatory mediator belonging to the alarmin family, has a key role in different acute and chronic immune disorders. Asthma is a complex disease characterised by recurrent and reversible airflow obstruction associated to airway hyper-responsiveness and airway inflammation.

Objective

This literature review aims to analyse advances on HMGB1 role, employment and potential diagnostic application in asthma.

Methods

We reviewed experimental studies that investigated the pathogenetic role of HMGB in bronchial airway hyper-responsiveness, inflammation and the correlation between HMGB1 level and asthma.

Results

A total of 19 studies assessing the association between HMGB1 and asthma were identified.

Conclusions

What emerged from this literature review was the confirmation of HMGB-1 involvement in diseases characterised by chronic inflammation, especially in pulmonary pathologies. Findings reported suggest a potential role of the alarmin in being a stadiation method and a marker of therapeutic efficacy; finally, inhibiting HMGB1 in humans in order to contrast inflammation should be the aim for future further studies.

     

Young transgenic hMTH1 mice are protected against dietary fat‐induced metabolic stress—implications for enhanced longevity

hMTH1 protects against mutation during oxidative stress. It degrades 8‐oxodGTP to exclude potentially mutagenic oxidized guanine from DNA. hMTH1 expression is linked to ageing. Its downregulation in cultured cells accelerates RAS‐induced senescence, and its overexpression in hMTH1‐Tg mice extends lifespan. In this study, we analysed the effects of a brief (5 weeks) high‐fat diet challenge (HFD) in young (2 months old) and adult (7 months old) wild‐type (WT) and hMTH1‐Tg mice. We report that at 2 months, hMTH1 overexpression ameliorated HFD‐induced weight gain, changes in liver metabolism related to mitochondrial dysfunction and oxidative stress. It prevented DNA damage as quantified by a comet assay. At 7 months old, these HFD‐induced effects were less severe and hMTH1‐Tg and WT mice responded similarly. hMTH1 overexpression conferred lifelong protection against micronucleus induction, however. Since the canonical activity of hMTH1 is mutation prevention, we conclude that hMTH1 protects young mice against HFD by reducing genome instability during the early period of rapid growth and maximal gene expression. hMTH1 protection is redundant in the largely non‐growing, differentiated tissues of adult mice. In hMTH1‐Tg mice, expression of a less heavily mutated genome throughout life provides a plausible explanation for their extended longevity.     

Preferring thin people does not imply derogating fat people. A rasch analysis of the implicit weight attitude

Objective:

The meaning of the implicit weight attitude in individuals of different weight by distinguishing the contribution of positive and negative associations to the overall measure was investigated.

Design and Methods:

The implicit weight attitude was assessed using the Implicit Association Test. A Rasch model was used to identify which stimuli most affected the implicit measure. Explicit attitudes were assessed with a thin‐fat preference scale, and thermometer scales for both thin and fat people. The sample consists of 510 individuals categorized according to their BMI.

Results and Conclusion:

A significant implicit preference for thin relative to fat people was observed in all weight groups. In normal weight and obese individuals, the preference was mostly affected by positive stimuli (more easily associated with thin than with fat people). In underweight individuals, the preference was mostly guided by positive (more easily associated with thin than with fat people) and negative (more easily associated with fat than with thin people) stimuli. In overweight individuals, all stimuli contributed to the preference in a similar way. In all weight groups, the implicit weight attitude correlated with the explicit preference and/or the thin thermometer, whereas it never correlated with the fat thermometer. A pro‐thin bias was observed in normal weight and obese individuals, whereas both a pro‐thin and an anti‐fat bias were observed in underweight individuals. A clear preference for thin people relative to fat people was observed in overweight individuals. Therefore, uncritically interpreting the implicit preference for thin people as a sign of derogating fat people might be misleading.     

The secret of Pianosa island: an Italian native population of European brown hare (<Emphasis Type="Italic">Lepus europaeus meridiei</Emphasis> Hilzheimer, 1906)

Given its relevance as a game species, the brown hare (Lepus europaeus Pallas, 1778) is one of the most managed and translocated mammals in Europe. In Italy, the species shows a genepool consisting of a mix of native and exotic lineages, due to translocations and introductions for hunting purposes. Some authors argued that the introduction of exotic brown hares could have caused the extinction of an endemic subspecies, L. e. meridiei Hilzheimer 1906, once present in central and northern Italy. Here we genetically characterized for the first time the brown hare population living in Pianosa island (part of the Tuscan Archipelago National Park) using 13 STR loci and a fragment of the mtDNA control region. All individuals analyzed share a unique haplotype, the L. europaeus haplotype Leu2, recognized as the ancestral mitochondrial lineage corresponding to the subspecies L. e. meridiei. Furthermore, considering autosomal markers, Pianosa brown hare population and current Italian peninsular population are genetically distinct. The discovery of this ancient population in a protected area, isolated and not affected by recent translocation/restocking events, has a great relevance in conservation and confirms the current presence of the endemic subspecies L. e. meridiei in Italy.     

Impact of long-term cropping of glyphosate-resistant transgenic soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merr.] on soil microbiome

The transgenic soybean [Glycine max (L.) Merrill] occupies about 80 % of the global area cropped with this legume, the majority comprising the glyphosate-resistant trait (Roundup Ready^®, GR or RR). However, concerns about possible impacts of transgenic crops on soil microbial communities are often raised. We investigated soil chemical, physical and microbiological properties, and grain yields in long-term field trials involving conventional and nearly isogenic RR transgenic genotypes. The trials were performed at two locations in Brazil, with different edaphoclimatic conditions. Large differences in physical, chemical and classic microbiological parameters (microbial biomass of C and N, basal respiration), as well as in grain production were observed between the sites. Some phyla (Proteobacteria, Actinobacteria, Acidobacteria), classes (Alphaproteobacteria, Actinomycetales, Solibacteres) and orders (Rhizobiales, Burkholderiales, Myxococcales, Pseudomonadales), as well as some functional subsystems (clustering-based subsystems, carbohydrates, amino acids and protein metabolism) were, in general, abundant in all treatments. However, bioindicators related to superior soil fertility and physical properties at Londrina were identified, among them a higher ratio of Proteobacteria:Acidobacteria. Regarding the transgene, the metagenomics showed differences in microbial taxonomic and functional abundances, but lower in magnitude than differences observed between the sites. Besides the site-specific differences, Proteobacteria, Firmicutes and Chlorophyta were higher in the transgenic treatment, as well as sequences related to protein metabolism, cell division and cycle. Although confirming effects of the transgenic trait on soil microbiome, no differences were recorded in grain yields, probably due to the buffering capacity associated with the high taxonomic and functional microbial diversity observed in all treatments.     

Proteomics analysis of a long‐term survival strain of Escherichia coli K‐12 exhibiting a growth advantage in stationary‐phase (GASP) phenotype

The aim of this work was the functional and proteomic analysis of a mutant, W3110 Bgl⁺/10, isolated from a batch culture of an Escherichia coli K‐12 strain maintained at room temperature without addition of nutrients for 10 years. When the mutant was evaluated in competition experiments in co‐culture with the wild‐type, it exhibited the growth advantage in stationary phase (GASP) phenotype. Proteomes of the GASP mutant and its parental strain were compared by using a 2DE coupled with MS approach. Several differentially expressed proteins were detected and many of them were successful identified by mass spectrometry. Identified expression‐changing proteins were grouped into three functional categories: metabolism, protein synthesis, chaperone and stress responsive proteins. Among them, the prevalence was ascribable to the “metabolism” group (72%) for the GASP mutant, and to “chaperones and stress responsive proteins” group for the parental strain (48%).     

Relationship of thrombopoietin and interleukin-11 levels to thrombocytopenia associated with dengue disease

Thrombocytopenia is one of the main clinical findings of dengue. In this work we examined the levels of thrombopoietin (TPO) and interleukin-11 (IL-11), two of the most potent regulators of platelet production, in serum from 28 patients with dengue fever (DF). Patients with DF had increased levels of TPO, compared with healthy individuals (p<0.005). Patients with dengue hemorrhagic fever (DHF, n=7), the more severe form of dengue, had higher TPO levels than patients with DF (p<0.001). Serum TPO levels and platelet counts were inversely correlated in both DF and DHF patients. IL-11 was detectable in neither DF nor DHF patients. Our results demonstrate that thrombocytopenia in dengue disease is associated with changes in the serum levels of TPO, but not IL-11, suggesting that this cytokine could be a potential early clinical marker of the severity of dengue disease.