The effect of flooding on the exchange of the volatile C₂-compounds ethanol, acetaldehyde and acetic acid between leaves of Amazonian floodplain tree species and the atmosphere

The effect of root inundation on the leaf emissions of ethanol, acetaldehyde and acetic acid in relation to assimilation and transpiration was investigated with 2–3 years old tree seedlings of four Amazonian floodplain species by applying dynamic cuvette systems under greenhouse conditions. Emissions were monitored over a period of several days of inundation using a combination of Proton Transfer Reaction Mass Spectrometry (PTR-MS) and conventional techniques (HPLC, ion chromatography). Under non-flooded conditions, none of the species exhibited measurable emissions of any of the compounds, but rather low deposition of acetaldehyde and acetic acid was observed instead. Tree species specific variations in deposition velocities were largely due to variations in stomatal conductance. Flooding of the roots resulted in leaf emissions of ethanol and acetaldehyde by all species, while emissions of acetic acid were only observed from the species exhibiting the highest ethanol and acetaldehyde emission rates. All three compounds showed a similar diurnal emission profile, each displaying an emission burst in the morning, followed by a decline in the evening. This concurrent behavior supports the conclusion, that all three compounds emitted by the leaves are derived from ethanol produced in the roots by alcoholic fermentation, transported to the leaves with the transpiration stream and finally partly converted to acetaldehyde and acetic acid by enzymatic processes. Co-emissions and peaking in the early morning suggest that root ethanol, after transportation with the transpiration stream to the leaves and enzymatic oxidation to acetaldehyde and acetate, is the metabolic precursor for all compounds emitted, though we can not totally exclude other production pathways. Emission rates substantially varied among tree species, with maxima differing by up to two orders of magnitude (25–1700 nmol m−2 min−1 for ethanol and 5–500 nmol m−2 min−1 for acetaldehyde). Acetic acid emissions reached 12 nmol m−2 min−1. The observed differences in emission rates between the tree species are discussed with respect to their root adaptive strategies to tolerate long term flooding, providing an indirect line of evidence that the root ethanol production is a major factor determining the foliar emissions. Species which develop morphological root structures allowing for enhanced root aeration produced less ethanol and showed much lower emissions compared to species which lack gas transporting systems, and respond to flooding with substantially enhanced fermentation rates and a non-trivial loss of carbon to the atmosphere. The pronounced differences in the relative emissions of ethanol to acetaldehyde and acetic acid between the tree species indicate that not only the ethanol production in the roots but also the metabolic conversion in the leaf is an important factor determining the release of these compounds to the atmosphere

Lytic and mechanical stability of clots composed of fibrin and blood vessel wall components.

Background Proteases expressed in atherosclerotic plaque lesions generate collagen fragments, release glycosaminoglycans (chondroitin sulfate [CS] and dermatan sulfate [DS]) and expose extracellular matrix (ECM) proteins (e.g. decorin) at sites of fibrin formation. Objective Here we address the effect of these vessel wall components on the lysis of fibrin by the tissue plasminogen activator (tPA)/plasminogen system and on the mechanical stability of clots. Methods and results MMP-8-digested collagen fragments, isolated CS, DS, glycosylated decorin and its core protein were used to prepare mixed matrices with fibrin (additives present at a 50-fold lower mass concentration than fibrinogen). Scanning electron microscopy (SEM) showed that the presence of ECM components resulted in a coarse fibrin structure, most pronounced for glycosylated decorin causing an increase in the median fiber diameter from 85 to 187 nm. Rheological measurements indicated that these structural alterations were coupled to decreased shear resistance (1.8-fold lower shear stress needed for gel/fluid transition of the clots containing glycosylated decorin) and rigidity (reduction of the storage modulus from 54.3 to 33.2 Pa). The lytic susceptibility of the modified fibrin structures was increased. The time to 50% lysis by plasmin was reduced approximately 2-fold for all investigated ECM components (apart from the core protein of decorin which produced a moderate reduction of the lysis time by 25%), whereas fibrin-dependent plasminogen activation by tPA was inhibited by up to 30%. Conclusion ECM components compromise the chemical and mechanical stability of fibrin as a result of changes in its ultrastructure

Az érfal trombogenitása és hatása a trombolizisre = Thrombogenicity of the vascular wall and its impact on thrombolysis

A projekt keretében az érfal – vérsejt interakciók a trombus keletkezésében betöltött szerepét és az így alakuló véralvadék litikus érzékenységét vizsgáltuk. Fő megállapításaink: 1. Leukocita eredetű proteázok (elasztáz, matrix metalloproteáz 8 és 9) úgy módosítják az érfal szerkezetét, hogy a vérlemezkék von Willebrand faktor (VWF)-függő adhéziója fokozódik. 2. A VWF jelenléte kivédi a fibrinogén plazminnal történő proteolízisét, így hozzájárul a vérlemezkék közötti fibrinogén hidak fenntartásához. 3. Sebészileg eltávolított trombusok hisztológiai feldolgozása igazolja a leukociták in vivo szerepét a trombusok feloldásában valamint a sejt-eredetű foszfolipidek és szabad zsírsavak trombuson belüli jelenlétét. 4. A zsírsavak növelik a szöveti plazminogén aktivátor (tPA) fibrin-specificitását azáltal, hogy fokozzák a plazminogén aktivációt fibrin felszínen, de gátolják azt homogén oldatban. 5. A zsírsavak gátolják a keletkező plazmint is kevert-típusú inhibitorként, míg a fibrin részben kivédi ezt a gátlóhatást. 6. Vérplazma eredetű immunoglobulin G módosítja a lipidek fibrinolízisre gyakorolt hatásait, méghozzá eltérő módon egészségeseknél és egyes kóros állapotokban. 7. Modell rendszerben az intermolekuláris béta-lemezek fokozzák a tPA-függő plazminogén aktivációt és emellett ilyen szerkezetek átmeneti megjelenése kimutatható a fibrinháló oldása során. Eredményeink alapul szolgálhatnak a trombusszerkezethez igazított trombolitikus eszközök tervezéséhez és fejlesztéséhez. | The research targeted the role of the interactions of the blood vessel wall and blood cells in the formation of thrombi, as well as the lytic susceptibility of the formed thrombi. Major results: 1. Leukocyte-derived proteases modify the structure of the arterial wall, so that the von Willebrand factor (VWF) dependent adhesion of platelets increases. 2. The presence of VWF protects fibrinogen against digestion with plasmin and thus contributes to the stability of the fibrinogen as adhesive glue between platelets. 3. Histological evidence from thrombi removed with surgery supports the in vivo role of leukocytes in the dissolution of thrombi as well as the presence of phospholipids and free fatty acids (FFA) in thrombi. 4. FFA increase the fibrin specificity of tissue plasminogen activator (tPA) through stimulation of plasminogen activation on fibrin surface and inhibition of tPA in solution. 5. FFA inhibit the generated plasmin in a mixed-type inhibitor pattern and fibrin protects plasmin against this inhibition. 6. Blood-derived immunoglobulin G modifies the lipid effects on fibrinolysis in a manner, which differs in healthy subjects and antiphospholipid syndrome patients. 7. In a model system intermolecular beta-sheets stimulate the tPA-dependent plasminogen activation and the presence of such structures can be shown transiently in the course of fibrin dissolution. Our results can be implemented in the design of thrombolytic tools tailored to specific thrombus structures

The effect of flooding on the exchange of the volatile C₂-compounds ethanol, acetaldehyde and acetic acid between leaves of Amazonian floodplain tree species and the atmosphere

International audienceThe effect of root inundation on the leaf emissions of ethanol, acetaldehyde and acetic acid was investigated with 2?3 years old tree seedlings of four Amazonian floodplain species by applying dynamic cuvette systems under greenhouse conditions. Emissions were monitored over a period of several days of inundation using a combination of Proton Transfer Reaction Mass Spectrometry (PTR-MS) and conventional techniques (HPLC, ion chromatography). Under non-flooded conditions, none of the species exhibited significant emissions of any of the compounds. A slight deposition of acetaldehyde and acetic acid was mainly observed, instead. Tree species specific variations in deposition velocities were largely due to variations in stomatal conductance. Flooding of the roots resulted in leaf emissions of ethanol and acetaldehyde by all species, while emissions of acetic acid occurred only by the species exhibiting the highest ethanol and acetaldehyde emission rates. All three compounds showed a similar diurnal emission profile, each displaying an emission burst in the morning, followed by a decline in the evening. This concurrent behavior supports the conclusion, that all three compounds emitted by the leaves are derived from ethanol produced in the roots by alcoholic fermentation, transported to the leaves with the transpiration stream and finally partly converted to acetaldehyde and acetic acid by enzymatic processes. Co-emissions and peaking in the early morning confirmed that root ethanol, after transportation with the transpiration stream to the leaves and enzymatic oxidation to acetaldehyde and acetate, is the metabolic precursor for all compounds emitted. Emission rates substantially varied among tree species, with maxima differing by up to two orders of magnitude (3?200 nmol m?2 min?1 for ethanol and 5?500 nmol m?2 min?1 for acetaldehyde). Acetic acid emissions reached 12 nmol m?2 min?1. The observed differences in emission rates between the tree species are discussed with respect to their root adaptive strategies to tolerate long term flooding, providing an indirect line of evidence that the root ethanol production is a major factor determining the foliar emissions. Species which develop morphological root structures allowing for enhanced root aeration produced less ethanol and showed much lower emissions compared to species which lack gas transporting systems, and respond to flooding with substantially enhanced fermentation rates. The pronounced differences in the relative emissions of ethanol to acetaldehyde and acetic acid between the tree species indicate that not only the ethanol production in the roots but also the metabolic conversion in the leaf is an important factor determining the release of these compounds to the atmosphere

Cause and Effect Analysis between Influencing Factors Related to Environmental Conditions, Hunting and Handling Practices and the Initial Microbial Load of Game Carcasses

Environmental, hunting and handling factors affect the microbial load of hunted game and the resulting meat products. The aim of this study was to systematically investigate the influence of several factors on the initial microbial load (IML) of game carcasses during the early hunting chain. Eviscerated roe deer body cavities (n = 24) were investigated in terms of total viable count and the levels of Pseudomonas spp., Lactobacillus spp., Enterobacteriaceae and Escherichia coli (E. coli). Furthermore, a risk analysis based on the obtained original IML data, literature search and a Failure Mode and Effects Analysis (FMEA) was performed. The IML could be explained in a regression model by factors including the higher body weight (BW), damaged gastrointestinal tract by the shot, ambient temperature or rain. The levels of Lactobacillus spp. (p = 0.0472), Enterobacteriaceae (p = 0.0070) and E. coli (p = 0.0015) were lower on the belly flap surface when gloves were used during evisceration. The literature search revealed that studies examining influencing factors (IF) on the IML of game carcasses found contradictory effects of the comparable IF on IML. Potential handling failures may lead to a higher IML of game carcasses during the early hunting chain ranked by FMEA. Several handling practices for game carcasses are recommended, such as ensuring efficient cooling of heavier BW carcasses to limit bacterial growth or eviscerating heavier carcasses before lighter ones

Struggle in the flood: tree responses to flooding stress in four tropical floodplain systems

This review examines species diversity and structural, physiological and biochemical characteristics associated with survival of annual deep flooding of trees in four contrasting tropical floodplain ecosystems