Does nitrate reductase play a key role in photoinduction of carotenoid synthesis in Neurospora crassa?

Does nitrate reductase play a key role in photoinduction of caroteniod synthesis in Neurospora crassa

Time-dependent systemic hemostatic effects of fibrin monomer in controlled liver injury in the experiment

Aim. To evaluate the hemostatic effect of fibrin monomer after its intravenous administration at different time periods in experimental trauma. Methods. In the experiments, in a placebo-controlled study, hemostatic and hemostasiological effects of systemic use of fibrin monomer were studied at different time periods after its administration (in 5 min, 1 h and 3 h) in 97 male rabbits of the Chinchilla breed in the controlled liver injury model. Results. A pronounced hemostatic effect was demonstrated for fibrin monomer used at a dose of 0.25 mg/kg demonstrated by a 6.3-fold decrease of blood loss volume (% of circulating blood volume) compared to placebo on the background of the intravenous preventive fibrin monomer administration 1 hour prior to controlled liver injury. Fibrin monomer administration at a stated dose was not accompanied by significant changes in haemocoagulative parameters including measurement of platelet count, activated partial thromboplastin time, prothrombin time, thrombin time, echitox time, fibrinogen concentration, level of soluble fibrin monomer complexes, D-dimer content, and antithrombin III activity. The effect of fibrin monomer is probably realized through some effectors, the nature of which has not yet been studied. The obtained results allow choosing the optimal interval between intravenous administrations of fibrin monomer and controlled liver injury for further study of the mechanisms of its hemostatic action. Conclusion. Fibrin monomer in small doses (0.25 mg/kg) is able to exert a pronounced hemostatic effect with its systemic administration 1 hour prior to the injury without significant changes in haemocoagulative parameters

Enzymatic Mechanisms Involved in Evasion of Fungi to the Oxidative Stress: Focus on Scedosporium apiospermum

The airways of patients with cystic fibrosis (CF) are frequently colonized by various filamentous fungi, mainly Aspergillus fumigatus and Scedosporium species. To establish within the respiratory tract and cause an infection, these opportunistic fungi express pathogenic factors allowing adherence to the host tissues, uptake of extracellular iron, or evasion to the host immune response. During the colonization process, inhaled conidia and the subsequent hyphae are exposed to reactive oxygen species (ROS) and reactive nitrogen species (RNS) released by phagocytic cells, which cause in the fungal cells an oxidative stress and a nitrosative stress, respectively. To cope with these constraints, fungal pathogens have developed various mechanisms that protect the fungus against ROS and RNS, including enzymatic antioxidant systems. In this review, we summarize the different works performed on ROS- and RNS-detoxifying enzymes in fungi commonly encountered in the airways of CF patients and highlight their role in pathogenesis of the airway colonization or respiratory infections. The potential of these enzymes as serodiagnostic tools is also emphasized. In addition, taking advantage of the recent availability of the whole genome sequence of S. apiospermum, we identified the various genes encoding ROS- and RNS-detoxifying enzymes, which pave the way for future investigations on the role of these enzymes in pathogenesis of these emerging species since they may constitute new therapeutics targets

Additive Contributions of Two Manganese-Cored Superoxide Dismutases (MnSODs) to Antioxidation, UV Tolerance and Virulence of Beauveria bassiana

The biocontrol potential of entomopathogenic fungi against arthropod pests depends on not only their virulence to target pests but tolerance to outdoor high temperature and solar UV irradiation. Two Beauveria bassiana superoxide dismutases (SODs), BbSod2 and BbSod3, were characterized as cytosolic and mitochondrial manganese-cored isoenzymes (MnSODs) dominating the total SOD activity of the fungal entomopathogen under normal growth conditions. To probe their effects on the biocontrol potential of B. bassiana, ΔBbSod2, ΔBbSod3, and three hairpin RNA-interfered (RNAi) mutants with the transcripts of both BbSod2 and BbSod3 being suppressed by 91–97% were constructed and assayed for various phenotypic parameters in conjunction with ΔBbSod2/BbSod2, ΔBbSod3/BbSod3 and wild-type (control strains). In normal cultures, the knockout and RNAi mutants showed significant phenotypic alterations, including delayed sporulation, reduced conidial yields, and impaired conidial quality, but little change in colony morphology. Their mycelia or conidia became much more sensitive to menadione or H2O2-induced oxidative stress but had little change in sensitivity to the hyperosmolarity of NaCl and the high temperature of 45°C. Accompanied with the decreased antioxidative capability, conidial tolerances to UV-A and UV-B irradiations were reduced by 16.8% and 45.4% for ΔBbSod2, 18.7% and 44.7% for ΔBbSod3, and ∼33.7% and ∼63.8% for the RNAi mutants, respectively. Their median lethal times (LT50s) against Myzus persicae apterae, which were topically inoculated under a standardized spray, were delayed by 18.8%, 14.5% and 37.1%, respectively. Remarkably, the effects of cytosolic BbSod2 and mitochondrial BbSod3 on the phenotypic parameters important for the fungal bioncontrol potential were additive, well in accordance with the decreased SOD activities and the increased superoxide levels in the knockout and RNAi mutants. Our findings highlight for the first time that the two MnSODs co-contribute to the biocontrol potential of B. bassiana by mediating cellular antioxidative response

SYSTEMIC HEMOSTATIC AND PROTHROMBOTIC EFFECTS OF FIBRIN-MONOMER IN EXPERIMENT WITH DOSED LIVER THERAPY

Objective of the study is to experimentally evaluate system hemostatic and prothrombotic effects of intravenous fibrin monomer (FM). Materials and methods. Eighty two Chinchilla rabbits weighing 3–4 kg were used in the study. In addition to the placebo, animals were administered an aqueous solution of fibrin monomer (FM) intravenously at doses of 0.1, 0.25, 0.5, 1.0, 2.5 and 5.0 mg/kg. After 1 hour, a standard liver injury was performed and the blood loss (% of the circulating blood volume) resulting from parenchymal hemorrhage was estimated. Hemostatic system examination included platelet number in venous blood and fibrinogen and D-dimer levels in blood plasma. Results and discussion. Blood loss after dosed injury with placebo was 10.0 [4.0; 15.7] % blood volume (median [25th percentile; 75th percentile]). FM preparation doses of 0.25, 2.5 and 5.0 mg/kg resulted in a decrease of blood loss by 6.3 (p < 0.001), 7.8 (p < 0.001) and 2.7 times (p = 0.04) (1.6 [1.0; 3.0], 1.3 [0.6; 1,6] and 3.7 [2.8; 5.3] % blood volume, respectively).High doses of FM preparation (2.5 and 5.0 mg/kg) minimized blood loss due to activation of coagulation and thrombus formation, which was illustrated by a 7.0–8.0-fold increase in D-dimer level (compared to placebo). 0.25 mg/kg of FM preparation did not lead to an increase of D-dimer content, although the blood loss was greatly reduced. Conclusion. The data obtained show the presence of unique hemostatic properties in low-dose FM preparation (0.25 mg/kg), which allows creating system hemostatic agents of a new generation