Sensitivity of yeasts to lithium

A wide range of tolerance to Li⁺ has been found among 12 different yeasts. Concentrations that do not allow long-term growth also arrest growth of an actively growing culture within 2–5 h. At the same concentrations protein and RNA synthesis are inhibited with little or no lag period (<50 min) but respiration is not affected at these concentrations. Lower concentrations that do not inhibit growth, may impair sporulation. For given extracellular conditions, intracellular Li⁺ concentrations are lower in the more tolerant yeast strains.     

Aluminium Stress Affects Nitrogen Fixation and Assimilation in Soybean (Glycine max L.)

Nitrogen fixation and assimilation in nodules and roots were studied in soybean (Glycine max L.) exposed to different levels of aluminium (Al) stress (0, 50, 200 and 500 μM). Al at 500 μM induced oxidative stress, which became evident from an increase in lipid peroxidation accompanied by a concomitant decline in antioxidant enzyme activities and leghaemoglobin breakdown. Consequently, there was also a reduction in nitrogenase activity. However, the leghaemoglobin levels and nitrogenase activity were unexpectedly found to be higher in nodules when the plants were treated with 200 μM Al. Of the enzymes involved in nitrogen assimilation, the activity of glutamate dehydrogenase-NADH was reduced in nodules under Al stress, but it was significantly higher in roots at 500 μM Al as compared to that in the control. In nodules, the glutamine synthetase/glutamate synthase-NADH pathway, assayed in terms of activity and expression of both the enzymes, was inhibited at >50 μM Al; but in roots this inhibitory effect was apparent only at 500 μM Al. No significant changes in ammonium and protein contents were recorded in the nodules or roots when the plants were treated with 50 μM Al. However, Al at ≥200 μM significantly increased the ammonium levels and decreased the protein content in the nodules. But these contrasting effects on ammonium and protein contents due to Al stress were observed in the roots only at 500 μM Al. The results suggest that the effect of Al stress on nitrogen assimilation is more conspicuous in nodules than that in the roots of soybean plants.     

Immunohistological signposts in central nervous system tumours with neuronal differentiation.

25 neuronal tumours with a panel of antibodies were studied and it was found that vimentin was present in 15 tumours. It was also found in a few cells within rosettes. PGP 9.5 showed a somatic pattern of staining with nuclear and perinuclear positivity in 23. Neurofilament reactivity was found in 14. Retinal S-antigen was detected only in one medulloblastoma, 3/4 pineal tumours and 2/2 retinoblastomas. Reactivity, for synaptophysin was present in 2/5 medulloblastomas, 3/10 neuroblastomas and 2/2 retinoblastomas. GFAP was demonstrated in scattered tumour cells in 4/5 medulloblastomas. Two of these were the only tumours featuring bipolar differentiation whilst it was unipolar in the remainder. The significance of these findings in relation to the ontogeny of these tumours is discussed.     

PARP-1 Regulates Metastatic Melanoma through Modulation of Vimentin-induced Malignant Transformation

PARP inhibition can induce anti-neoplastic effects when used as monotherapy or in combination with chemo- or radiotherapy in various tumor settings; however, the basis for the anti-metastasic activities resulting from PARP inhibition remains unknown. PARP inhibitors may also act as modulators of tumor angiogenesis. Proteomic analysis of endothelial cells revealed that vimentin, an intermediary filament involved in angiogenesis and a specific hallmark of EndoMT (endothelial to mesenchymal transition) transformation, was down-regulated following loss of PARP-1 function in endothelial cells. VE-cadherin, an endothelial marker of vascular normalization, was up-regulated in HUVEC treated with PARP inhibitors or following PARP-1 silencing; vimentin over-expression was sufficient to drive to an EndoMT phenotype. In melanoma cells, PARP inhibition reduced pro-metastatic markers, including vasculogenic mimicry. We also demonstrated that vimentin expression was sufficient to induce increased mesenchymal/pro-metastasic phenotypic changes in melanoma cells, including ILK/GSK3-β-dependent E-cadherin down-regulation, Snail1 activation and increased cell motility and migration. In a murine model of metastatic melanoma, PARP inhibition counteracted the ability of melanoma cells to metastasize to the lung. These results suggest that inhibition of PARP interferes with key metastasis-promoting processes, leading to suppression of invasion and colonization of distal organs by aggressive metastatic cells.     

Recurrences and Human Agential Meaning Grounding: Laying a Path in Walking

This article addresses the semiotic problem of how meaning is agentially grounded: how actual meaning is possible and is justifiably supported by agents’ capabilities and purposes. This article is particularly focused on human agential grounding; however, to a great degree, insights presented here can be extended to other living beings. Specifically, agential meaning is examined here inside the framework of agentive semiotics and embodied, situated and enactive cognition theories, in line with the mind-life continuity general thesis (which intends to naturalize mind and experience). To offer clarity and methodological precision about agential grounding, three explanation categories (called recurrences) are proposed: phylogenetic recurrence, the evolutionary basis for corporal/embodied grounding; ontogenetic recurrence, the developmental basis for individual meaning grounding; and collective recurrence, the basis for meaning recognized, attributed and assigned inside social contexts. These recurrences are conceived as three types of general processes that constantly enclose possibilities for purpose and meaning emergence in humans. As a result of these types of recurrences, two categories of human agendas or purposes are also proposed: individual and collective. Finally, remarks about how these categories can be useful for semiotic analysis and further research are suggested.     

Hybrid Cluster Proteins and Flavodiiron Proteins Afford Protection to Desulfovibrio vulgaris upon Macrophage Infection

Desulfovibrio species are Gram-negative anaerobic sulfate-reducing bacteria that colonize the human gut. Recently, Desulfovibrio spp. have been implicated in gastrointestinal diseases and shown to stimulate the epithelial immune response, leading to increased production of inflammatory cytokines by macrophages. Activated macrophages are key cells of the immune system that impose nitrosative stress during phagocytosis. Hence, we have analyzed the in vitro and in vivo responses of Desulfovibrio vulgaris Hildenborough to nitric oxide (NO) and the role of the hybrid cluster proteins (HCP1 and HCP2) and rubredoxin oxygen oxidoreductases (ROO1 and ROO2) in NO protection. Among the four genes, hcp2 was the gene most highly induced by NO, and the hcp2 transposon mutant exhibited the lowest viability under conditions of NO stress. Studies in murine macrophages revealed that D. vulgaris survives incubation with these phagocytes and triggers NO production at levels similar to those stimulated by the cytokine gamma interferon (IFN-γ). Furthermore, D. vulgaris hcp and roo mutants exhibited reduced viability when incubated with macrophages, revealing that these gene products contribute to the survival of D. vulgaris during macrophage infection.     

Conditionally lethal genes in the N pilus region of plasmid pCU1.

Plasmid genes or regions that are conditionally lethal to Escherichia coli have been called kil and those lethal to Klebsiella but not to E. coli have been called kik. Both classes of genes are found in or close to the N pilus region of the plasmid pCU1 and the closely related plasmid pKM101. Here we describe two new and overlapping lethal genes that are located between kikA and traA of the plasmid pCU1 and display host specificity. KilC is lethal in E. coli and Klebsiella while kikC is lethal only in Klebsiella. The previously identified korA gene is sufficient to override the lethality of kilC in trans or in cis but is insufficient to override kikC. kilC expression in E. coli leads to cell death accompanied by an increase in average cell length without affecting septum formation.     

Lipophilic 9,10‐Dehydrofukinone Action on Pathogenic and Non‐Pathogenic Bacterial Biofilms. Why Is This Main Volatile Metabolite in Senecio?

The effect of a natural sesquiterpene ketone, 9,10‐dehydrofukinone (DHF), on pathogenic Staphylococcus aureus and Pseudomonas aeruginosa strains isolated from chronic infectious processes, was the focus of the present study. Lipophilic DHF produced important antibacterial synergistic effects in association with ciprofloxacin (CPX) against two biofilm‐forming strains of S. aureus HT1 (FIC=0.21) and P. aeruginosa HT5 (FIC=0.05). Hence, this mixture constitutes an excellent strategy to combat these biofilm‐producing bacteria that overexpress drug efflux pumps as a resistance mechanism. Additionally, a substantial rise in beneficial Lactobacillus biofilm biomass was determined as a very significant finding of this association. Particularly, a non‐pathogenic biofilm increment of 119 % was quantified when the mixture was added to a probiotic L. acidophilus ATCC SD‐5212 culture. A surface activity enhanced in 71 % with respect to untreated L. acidophilus culture was also generated by the DHF and CPX association, and therefore, a glycoprotein synthesis induction mediated by the mixture is discussed. The results obtained could help in the development of new selective antibiotics. From an ecological standpoint, the present study strongly suggests that DHF is a polyfunctional organic molecule produced with a high yield in Senecio punae that exerts a positive impact on a non‐pathogenic plant bacterium L. plantarum CE105.