Influenza A Viruses Grow in Human Pancreatic Cells and Cause Pancreatitis and Diabetes in an Animal Model

Influenza A viruses commonly cause pancreatitis in naturally and experimentally infected animals. In this study, we report the results of in vivo investigations carried out to establish whether influenza virus infection could cause metabolic disorders linked to pancreatic infection. In addition, in vitro tests in human pancreatic islets and in human pancreatic cell lines were performed to evaluate viral growth and cell damage. Infection of an avian model with two low-pathogenicity avian influenza isolates caused pancreatic damage resulting in hyperlipasemia in over 50% of subjects, which evolved into hyperglycemia and subsequently diabetes. Histopathology of the pancreas showed signs of an acute infection resulting in severe fibrosis and disruption of the structure of the organ. Influenza virus nucleoprotein was detected by immunohistochemistry (IHC) in the acinar tissue. Human seasonal H1N1 and H3N2 viruses and avian H7N1 and H7N3 influenza virus isolates were able to infect a selection of human pancreatic cell lines. Human viruses were also shown to be able to infect human pancreatic islets. In situ hybridization assays indicated that viral nucleoprotein could be detected in beta cells. The cytokine activation profile indicated a significant increase of MIG/CXCL9, IP-10/CXCL10, RANTES/CCL5, MIP1b/CCL4, Groa/CXCL1, interleukin 8 (IL-8)/CXCL8, tumor necrosis factor alpha (TNF-α), and IL-6. Our findings indicate that influenza virus infection may play a role as a causative agent of pancreatitis and diabetes in humans and other mammals.     

Reactive oxygen species, ascorbate–glutathione pool, and enzymes of their metabolism in drought-sensitive and tolerant indica rice (Oryza sativa L.) seedlings subjected to progressing levels of water deficit

Water deficit for rice is a worldwide concern, and to produce drought-tolerant varieties, it is essential to elucidate molecular mechanisms associated with water deficit tolerance. In the present study, we investigated the differential responses of nonenzymatic antioxidants ascorbate (AsA), glutathione (GSH), and their redox pool as well as activity levels of enzymes of ascorbate–glutathione cycle in seedlings of drought-sensitive rice (Oryza sativa L.) cv. Malviya-36 and drought-tolerant cv. Brown Gora subjected to water deficit treatment of ?1.0 and ?2.1 MPa for 24–72 h using PEG-6000 in sand cultures. Water deficit caused increased production of reactive oxygen species such as O₂?^?, H₂O₂, and HO? in the tissues, and the level of production was higher in the sensitive than the tolerant cultivar. Water deficit caused reduction in AsA and GSH and decline in their redox ratios (AsA/DHA and GSH/GSSG) with lesser decline in tolerant than the sensitive seedlings. With progressive level of water deficit, the activities of monodehydroascorbate reductase, dehydroascorbate reductase, ascorbate peroxidase (APX), and glutathione transferase increased in the seedlings of both rice cultivars, but the increased activity levels were higher in the seedlings of drought-tolerant cv. Brown Gora compared to the sensitive cv. Malviya-36. Greater accumulation of proline was observed in stressed seedlings of tolerant than the sensitive cultivar. In-gel activity staining of APX revealed varying numbers of their isoforms and their differential expression in sensitive and tolerant seedlings under water deficit. Results suggest that an enhanced oxidative stress tolerance by a well-coordinated cellular redox state of ascorbate and glutathione in reduced forms and induction of antioxidant defense system by elevated activity levels of enzymes of ascorbate–glutathione cycle is associated with water deficit tolerance in rice.     

The impact of oxidative stress in thiamine deficiency: A multifactorial targeting issue

Thiamine (vitamin B1) deficiency, the underlying cause of Wernicke–Korsakoff syndrome, is associated with the development of focal neuronal loss in vulnerable areas of the brain. Although the actual mechanism(s) that lead to the selective histological lesions characteristic of this disorder remain unresolved, oxidative stress has been shown to play a major role in its pathophysiology. In this review, the multifactorial influence of oxidative stress on a variety of processes known to take part in the development of structural lesions in TD including excitotoxicity, neuroinflammation, blood–brain barrier integrity, mitochondrial integrity, apoptosis, nucleic acid function, and neural stem cells will be discussed, and therapeutic strategies undertaken for treating neurodegeneration examined which may have an impact on the future treatment of this important vitamin deficiency.     

Drought impacts on biogeochemistry and microbial processes in salt marsh sediments: a flow-through reactor approach

The effects of drought on salt marsh sediments from Sapelo Island, Georgia, were examined in flow-through reactor experiments. Three hydrological treatments were employed: a continuously flooded anoxic control, a periodic drought treatment that experienced alternate periods of flooding and drying, and a severe drought treatment, where sediment was exposed to drought (drying) for several weeks and then flooded; the effect of both buffered and non-buffered flooding solutions were examined. In permanently anoxic sediments as well as in sediments exposed to drought, organic carbon oxidation was dominated by SO₄ ^2? reduction (SR) and SR rates increased over time. The shift from anoxic to oxic conditions in drought treatments significantly altered sediment geochemistry and pathways of microbial metabolism. Drought conditions favored suboxic mineralization processes, such as Fe(III) reduction and denitrification, which was fueled by NH₄ ⁺ oxidation promoted by O₂ delivered during drought conditions. Other major drought-induced changes included pH decrease, and altered concentrations of solid phase adsorbed metals.     

Development of a chemically defined medium for the production of the antibiotic platensimycin by Streptomyces platensis

The actinomycete Streptomyces platensis produces two compounds that display antibacterial activity: platensimycin and platencin. These compounds were discovered by the Merck Research Laboratories, and a complex insoluble production medium was reported. We have used this medium as our starting point in our studies. In a previous study, we developed a semi-defined production medium, i.e., PM5. In the present studies, by varying the concentration of the components of PM5, we were able to develop a superior semi-defined medium, i.e., PM6, which contains a higher concentration of lactose. Versions of PM6, containing lower concentrations of all components, were also found to be superior to PM5. The new semi-defined production media contain dextrin, lactose, MOPS buffer, and ammonium sulfate in different concentrations. We determined antibiotic production capabilities using agar diffusion assays and chemical assays via thin-layer silica chromatography and high-performance liquid chromatography. We reduced crude nutrient carryover from the seed medium by washing the cells with distilled water. Using these semi-defined media, we determined that addition of the semi-defined component soluble starch stimulated antibiotic production and that it and dextrin could both be replaced with glucose, resulting in the chemically defined medium, PM7.     

Experimental removal and addition of leaf litter inputs reduces nitrate production and loss in a lowland tropical forest

Environmental perturbations such as changes in land use, climate, and atmospheric carbon dioxide concentrations may alter organic matter inputs to surface soils. While the carbon (C) cycle response to such perturbations has received considerable attention, potential responses of the soil nitrogen (N) cycle to changing organic matter inputs have been less well characterized. Changing litter inputs to surface to soils may alter the soil N cycle directly, by controlling N substrate availability, or indirectly, via interactions with soil C biogeochemistry. We investigated soil N-cycling responses to a leaf litter manipulation in a lowland tropical forest using isotopic and molecular techniques. Both removing and doubling leaf litter inputs decreased the size of the soil nitrate pool, gross nitrification rates, and the relative abundance of ammonia-oxidizing microorganisms. Gross nitrification rates were correlated with the relative abundance of ammonia-oxidizing archaea, and shifts in the N-cycling microbial community composition correlated with concurrent changes in edaphic properties, notably pH and C:N ratios. These results highlight the importance of understanding coupled biogeochemical cycles in global change scenarios and suggest that environmental perturbations that alter organic matter inputs in tropical forests could reduce inorganic N losses to surface waters and the atmosphere by limiting nitrate production.     

24 Evolutionary dynamics of inteins in bacteria

Inteins are protein sequences that autocatalytically splice themselves out of protein precursors – analogous to introns – and ligate the flanking regions into a functional protein. Inteins are present in all three kingdoms of life, but have a sporadic distribution. They are found predominantly in proteins involved in DNA replication and repair such as helicases. The distribution of inteins suggests an adaptive function. The evolutionary forces which shaped the observed distribution of inteins are generally unknown. Some authors view inteins only as the selfish elements and argue that frequent horizontal transfer is behind inteins sporadic dissemination (Gogarten et al., 2002). On the other hand, the ancient nature of the inteins and the process of gain/loss could lead to the scattered distribution of inteins among species (Pietrokovski, 2001). It is necessary to note that the exclusively selfish nature of inteins is questionable; recent findings support the hypothesis of possible functional roles of inteins in protein regulation (Callahan et al., 2011). Moreover, both hypotheses were built on a limited number of the intein representatives. The amount of genomic data available for bacteria is enormous and in silico analysis for diverse inteins is warranted. We decided to take advantage of these microbial genomic data and performed comprehensive mining for the inteins using a bioinformatic pipeline. Altogether, 1757 species were analysed from 19 major phyla yielding more than 4500 intein-like sequences. The majority of these bacterial inteins were not described previously. Approximately 55% of the inteins were found in polymerases, helicases, or recombinases (Figure 1). Phylogenetic analysis indicated the complex evolutionary dynamics of inteins which includes horizontal transfers, high evolutionary rates coupled with recurrent gains, and losses. The preponderance of inteins in helicases and reductases is being investigated in terms of functional relevance.