Host cystathionine-γ lyase derived hydrogen sulfide protects against Pseudomonas aeruginosa sepsis

Hydrogen sulfide (H₂S) has recently been recognized as a novel gaseous transmitter with several anti-inflammatory properties. The role of host- derived H₂S in infections by Pseudomonas aeruginosa was investigated in clinical and mouse models. H₂S concentrations and survival was assessed in septic patients with lung infection. Animal experiments using a model of severe systemic multidrug-resistant P. aeruginosa infection were performed using mice with a constitutive knock-out of cystathionine-γ lyase (Cse) gene (Cse^-/-) and wild-type mice with a physiological expression (Cse^+/+). Experiments were repeated in mice after a) treatment with cyclophosphamide; b) bone marrow transplantation (BMT) from a Cse^+/+ donor; c) treatment with H₂S synthesis inhibitor aminooxyacetic acid (ΑΟΑΑ) or propargylglycine (PAG) and d) H₂S donor sodium thiosulfate (STS) or GYY3147. Bacterial loads and myeloperoxidase activity were measured in tissue samples. The expression of quorum sensing genes (QS) was determined in vivo and in vitro. Cytokine concentration was measured in serum and incubated splenocytes. Patients survivors at day 28 had significantly higher serum H₂S compared to non-survivors. A cut- off point of 5.3 μΜ discriminated survivors with sensitivity 92.3%. Mortality after 28 days was 30.9% and 93.7% in patients with H₂S higher and less than 5.3 μΜ (p = 7 x 10⁻⁶). In mice expression of Cse and application of STS afforded protection against infection with multidrug-resistant P. aeruginosa. Cyclophosphamide pretreatment eliminated the survival benefit of Cse^+/+ mice, whereas BMT increased the survival of Cse^-/- mice. Cse^-/- mice had increased pathogen loads compared to Cse^+/+ mice. Phagocytic activity of leukocytes from Cse^-/- mice was reduced but was restored after H₂S supplementation. An H₂S dependent down- regulation of quorum sensing genes of P.aeruginosa could be demonstrated in vivo and in vitro. Endogenous H₂S is a potential independent parameter correlating with the outcome of P. aeruginosa. H₂S provides resistance to infection by MDR bacterial pathogens.     

The transmittable through stinging microbiota differs between honeybees and wasps: a potentially greater microbial risk of the wasp sting for humans

International Microbiology -     

Biogeochemical Implications of Episodic Impoundment in a Restored Tidal Marsh of San Francisco Bay,California

Impounded tidal conditions often compromise coastal marsh restoration goals, through vegetation loss and other biogeochemical feedbacks. To determine if episodic marsh impoundments could be partially responsible for the observed cordgrass (Spartina foliosa) dieback at Crissy Field, Golden Gate National Recreation Area, we examined sulfur chemistry and plant stress along transects between and during tidal inlet closure events from 2007 to 2008. During closures, porewater sulfide (PW S^2?) concentrations did not respond consistently among sites, nor did they increase to levels likely to cause stress damage to cordgrass (>1 mM). However, sediment solid‐phase total reduced sulfur (TRS) concentrations did respond strongly to closures both at surface and subsurface depth intervals, and they were greatest in sites with high organic matter content (>5%). The temporal patterns of both PW S^2? and TRS suggest that while sulfate reduction may be enhanced during closure events, the free sulfide produced is largely precipitated into solid‐phase minerals. Even without millimolar levels of PW S^2?, plant stress was observed during closures, as indicated by a buildup of ethanol in root tissues, a by‐product of fermentative respiration brought on by limited oxygen availability. Further, enhanced sulfate reduction may be related to the higher relative concentrations of methylmercury in low intertidal surface sediments observed during closure events. These data suggest that, in support of vegetated tidal marsh restoration goals, tidal flows should be maintained actively to reduce the impact of impoundment events on marsh biogeochemistry and productivity.     

Multispectral optoacoustic tomography of muscle perfusion and oxygenation under arterial and venous occlusion: A human pilot study

Perfusion and oxygenation are critical parameters of muscle metabolism in health and disease. They have been both the target of many studies, in particular using near‐infrared spectroscopy (NIRS). However, difficulties with quantifying NIRS signals have limited a wide dissemination of the method to the clinics. Our aim was to investigate whether clinical multispectral optoacoustic tomography (MSOT) could enable the label‐free imaging of muscle perfusion and oxygenation under clinically relevant challenges: the arterial and venous occlusion. We employed a hybrid clinical MSOT/ultrasound system equipped with a hand‐held scanning probe to visualize hemodynamic and oxygenation changes in skeletal muscle under arterial and venous occlusions. Four (N = 4) healthy volunteers were scanned over the forearm for both 3‐minute occlusion challenges. MSOT‐recorded pathophysiologically expected results during tests of disturbed blood flow with high resolution and without the need for contrast agents. During arterial occlusion, MSOT‐extracted Hb‐values showed an increase, while HbO₂‐ and total blood volume (TBV)‐values remained roughly steady, followed by a discrete increase during the hyperemic period after cuff deflation. During venous occlusion, results showed a clear increase in intramuscular HbO₂, Hb and TBV within the segmented muscle area. MSOT was found to be capable of label‐free non‐invasive imaging of muscle hemodynamics and oxygenation under arterial and venous occlusion. We introduce herein MSOT as a novel modality for the assessment of vascular disorders characterized by disturbed blood flow, such as acute limb ischemia and venous thrombosis.     

Philosophy and practice of variety-independent gene transfer into recalcitrant crops

Summary Commercialization and marketing of agricultural products derived from recombinant DNA technologies is now becoming a reality. Genetically engineered tomatoes are poised to appear in supermarket shelves in the United States sometime next year, with other crops, including cotton, maize, soybean, rapeseed, potatoes, cucurbids, raspberries and others, scheduled for release 1 to 2 yr later (Hamilton and Ellis, 1992). One of the major breakthroughs responsible for the rapid creation of commercializable products has been the development of gene transfer methods capable of introducing foreign DNA into elite germplasm. This review examines some of the principles and applications of such gene transfer technologies in relation to conventional alternatives that are limited by cell culture, host, and genotype. Advantages and disadvantages of various gene transfer methods will be discussed. Special emphasis will be given to particle bombardment, as methods based on this technology paved the way for the engineering of a number of important agronomic species. Presented in the Session-in-Depth New Approaches to Plant transformation at the 1992 World Congress on Cell and Tissue Culture, Washington, DC, June 20–25, 1992.     

Systems Biology: The elements and principles of Life

Systems Biology has a mission that puts it at odds with traditional paradigms of physics and molecular biology, such as the simplicity requested by Occam’s razor and minimum energy/maximal efficiency. By referring to biochemical experiments on control and regulation, and on flux balancing in yeast, we show that these paradigms are inapt. Systems Biology does not quite converge with biology either: Although it certainly requires accurate ‘stamp collecting’, it discovers quantitative laws. Systems Biology is a science of its own, discovering own fundamental principles, some of which we identify here.     

Purification and properties of the antizymes of Escherichia coli to ornithine decarboxylase

The purification of the antizymes to ornithine decarboxylase of Escherichia coli to homogeneity is detailed. An acidic component, pI 3.8, and two basic histone-like proteins, pI above 9.5, are described. The two latter proteins constitute approximately 90% of the total antizyme activity.     

Coralligène formations in the eastern Mediterranean Sea: Morphology, distribution, mapping and relation to fisheries in the southern Aegean Sea (Greece) based on high-resolution acoustics

Coralline algae are one of the most important constructors of biogenic habitats. In the Mediterranean Sea, the dominant coralline algae species form crusts comprising formations known as coralligène, considered as very important fishing grounds by fishermen. Due to the destructive effect of fishing gear activities over coralligène, these formations were recently protected from the use of active benthic gears by the EU 1967/2006 Mediterranean fisheries management Regulation. However, the lack of maps and information on their distribution makes the effective application of these measures impossible. The present publication contributes to the mapping of coralligène in the southern Aegean Sea (eastern Mediterranean), and to the study of coralline algae formation morphology, distribution, development conditions and relation to fisheries using a combination of single-beam echo sounder, sidescan sonar, sub-bottom profiler recordings and biological and sedimentological ground-truthing techniques. The coralligène formations were recognized as two distinct acoustic signatures of localized backscatter facies distinguishable from other hard substrate reflectors at depths ranging from 55.9 to 114.0 m, but mainly between 70 and 90 m. Two types of formations were identified: minute reefs 0.5-2.5 m in height and superficial layer formations no more than 0.2 m thick over the substrate. The seismic profiles revealed a cavernous internal structure of the minute reefs and recorded their development on both hard and soft substrates. The distribution of formations was contagious, creating aggregations. The finding of superficial layer formations and coralline shreds around minute coralligène reefs indicated that the former could be an intermediate development type between isolated small coralline pebbles, rhodoliths, and minute reefs. Regarding the development conditions, sidescan sonar imagery indicated that the optimal conditions for the establishment and development of coralligène formations are medium intensity currents. Concerning human activity over coralligène, trawl traces were recorded near but not over minute reefs and both near and crossing superficial layer type aggregations, while a submarine cable was also recorded among minute reefs. The mapping of coralligène aggregation areas is essential for the application of the EU Regulation and the protection of this important marine habitat.     

Prediction of germ-line transformation events in chimeric Ro transgenic soybean plantlets using tissue-specific expression patterns

Chimeric soybean plants derived from electric discharge particle acceleration experiments were used to develop relationships between tissue-specific expression patterns of a marker gene and germ-line transformation events in R_o plants. Using the GUS histochemical assay the likelihood of germ-line transformation was correlated to the localization of enzyme activity in specific tissues of the parent plant. The expression patterns of the 35S-GUS marker gene in specific tissue types in R_o plants and correlation with transmission of the introduced gene to progeny allowed the production of a clear picture of the development of these plants and their germ-line cells. Advances reported in this article resulted in the development of a commercial process for the genetic improvement of this important staple crop which until recently was very recalcitrant to conventional transformation methods.     

Food web structure variability in the surface layer, at a fixed station influenced by the North Western Mediterranean Current

The structure of the planktonic community and the influence of mesozooplankton migration on the microbial food web were investigated during six diel studies from June 92 to June 93 in the surface waters of a station in the North-Western Mediterranean Sea. Each diel study consisted of sampling at 5 and 40 m every 3 h over 24 h. Most of the times diel cycles did not show any convincing diel patterns in any of the variables studied. Clear zooplankton migration was evident in only two diel studies.The ratio of heterotrophic/autotrophic biomasses varied from 0.68 to 3.0, with a strong dominance of the heterotrophic biomass under oligotrophic conditions. Differences in food web structure were probably related to the influences of coastal water and the North-Western Mediterranean Current. Thus we found that the planktonic food web variability relatable to hydrodynamic variability, to be greater than diel variability. However, very large differences in food web structure among dates were evident. For example proportion of Chl a found in the <10 µm fraction varied from 18 to 96%.