High-dose rapamycin exerts a temporary impact on T. reesei RUT-C30 through gene trFKBP12

Background Knowledge with respect to regulatory systems for cellulase production is prerequisite for exploitation of such regulatory networks to increase cellulase production, improve fermentation efficiency and reduce the relevant production cost. The target of rapamycin (TOR) signaling pathway is considered as a central signaling hub coordinating eukaryotic cell growth and metabolism with environmental inputs. However, how and to what extent the TOR signaling pathway and rapamycin are involved in cellulase production remain elusive. Result At the early fermentation stage, high-dose rapamycin (100 μM) caused a temporary inhibition effect on cellulase production, cell growth and sporulation of Trichoderma reesei RUT-C30 independently of the carbon sources, and specifically caused a tentative morphology defect in RUT-C30 grown on cellulose. On the contrary, the lipid content of T. reesei RUT-C30 was not affected by rapamycin. Accordingly, the transcriptional levels of genes involved in the cellulase production were downregulated notably with the addition of rapamycin. Although the mRNA levels of the putative rapamycin receptor trFKBP12 was upregulated significantly by rapamycin, gene trTOR (the downstream effector of the rapamycin–FKBP12 complex) and genes associated with the TOR signaling pathways were not changed markedly. With the deletion of gene trFKBP12, there is no impact of rapamycin on cellulase production, indicating that trFKBP12 mediates the observed temporary inhibition effect of rapamycin. Conclusion Our study shows for the first time that only high-concentration rapamycin induced a transient impact on T. reesei RUT-C30 at its early cultivation stage, demonstrating T. reesei RUT-C30 is highly resistant to rapamycin, probably due to that trTOR and its related signaling pathways were not that sensitive to rapamycin. This temporary influence of rapamycin was facilitated by gene trFKBP12. These findings add to our knowledge on the roles of rapamycin and the TOR signaling pathways play in T. reesei.

High-dose rapamycin excerts a temporary impact on T. reesei through gene trFKBP12

Background: Knowledge with respect to regulatory systems for cellulase production is prerequisite for exploitation of such regulatory networks to increase cellulase production, improve fermentation efficiency and reduce the relevant production cost. The TOR (Target of Rapamycin) signaling pathway is considered as a central signaling hub coordinating eukaryotic cell growth and metabolism with environmental inputs. However, how and to what extent the TOR signaling pathway and rapamycin are involved in cellulase production remains elusive. Result: At the early fermentation stage, high-dose rapamycin (100 μM) caused a temporary inhibition effect on cellulase production, cell growth and sporulation of Trichoderma reesei independently of the carbon sources, and specifically caused a tentative morphology defect in RUT-C30 grown on cellulose. On the contrary, the lipid content of T. reesei was not affected by rapamycin. Accordingly, the transcriptional levels of genes involved in the cellulase production were downregulated notably with the addition of rapamycin. Although the mRNA levels of the putative rapamycin receptor trFKBP12 was upregulated significantly by rapamycin, gene trTOR (the downstream effector of the rapamycin-FKBP12 complex) and genes associated with the TOR signaling pathways were not changed markedly. With the deletion of gene trFKBP12, there is no impact of rapamycin on cellulase production, indicating that trFKBP12 mediates the observed temporary inhibition effect of rapamycin. Conclusion: Our study shows for the first time that only high-concentration rapamycin induced a transient impact on T. reesei at its early cultivation stage, demonstrating T. reesei is highly resistant to rapamycin, probably due to that trTOR and its related signaling pathways were not that sensitive to rapamycin. This temporary influence of rapamycin was facilitated by gene trFKBP12. These findings add to our knowledge on the roles of rapamycin and the TOR signaling pathways play in T. reesei.

Postexposure Administration of a Yersinia pestis Live Vaccine for Potentiation of Second-Line Antibiotic Treatment Against Pneumonic Plague

Pneumonic plague, caused by Yersinia pestis, is a rapidly progressing contagious disease. In the plague mouse model, a single immunization with the EV76 live attenuated Y. pestis strain rapidly induced the expression of hemopexin and haptoglobin in the lung and serum, both of which are important in iron sequestration. Immunization against a concomitant lethal Y. pestis respiratory challenge was correlated with temporary inhibition of disease progression. Combining EV76-immunization and second-line antibiotic treatment, which are individually insufficient, led to a synergistic protective effect that represents a proof of concept for efficient combinational therapy in cases of infection with antibiotic-resistant strains.

Temporary Inhibition of the Corrosion of AZ31B Magnesium Alloy by Formation of Bacillus subtilis Biofilm in Artificial Seawater

It is well known that microorganisms tend to form biofilms on metal surfaces to accelerate/decelerate corrosion and affect their service life. Bacillus subtilis was used to produce a dense biofilm on an AZ31B magnesium alloy surface. Corrosion behavior of the alloy with the B. subtilis biofilm was evaluated in artificial seawater. The results revealed that the biofilm hampered extracellular electron transfer significantly, which resulted in a decrease of icorr and increase of Rt clearly compared to the control group. Moreover, an ennoblement of Ecorr was detected under the condition of B. subtilis biofilm covering. Significant reduction of the corrosion was observed by using the cyclic polarization method. All of these prove that the existence of the B. subtilis biofilm effectively enhances the anti-corrosion performance of the AZ31B magnesium alloy. This result may enhance the usage of bio-interfaces for temporary corrosion control. In addition, a possible corrosion inhibition mechanism of B. subtilis on AZ31B magnesium alloy was proposed.

Adaptation of corn plants to chronic ultraviolet irradiation

Aim. The adaptation of young corn plants (Zea mays L.) to the effect of chronic ultraviolet B (UV-B) irradiation during vegetative growth and formation of photosynthetic apparatus of leaves was studied. Methods. Corn plants hybrid Dostatok 300 MB in the phase of two developed leaves was irradiated with UV-B in dose of 2 kJ/m2 per day with a power of 1 W/m2 in long day conditions during 12 days. During this period, the growth of plants was measured, content of photosynthetic pigments and endogenous hydrogen peroxide (HP) was determined in the leaves. Results. It was established that the effect of chronic UV‑B irradiation caused the temporary inhibition of leaf growth, synthesis of photosynthetic pigments and increasing of HP content in them. Then the growth processes and pigment complex recovered to the level of no irradiated plants and exceed it, indicating the induction of adaptive reactions in young corn plants. Conclusions. It was shown that the effect of a low dose of chronic UV-B irradiation caused a delay in growth processes and the formation of a photosynthetic complex with subsequent adaptation to stress in young corn plants. Keywords: UV-B irradiation, Zea mays L., photosynthetic pigments, adaptation.

To grow or not to grow: Postantibiotic effect is the question

Temporary inhibition of Escherichia coli growth in vitro after antibiotic administration is proportional to total antibiotic quantity.

INVESTIGATION OF SOLID PHASE BEHAVIOR DURING PROCESS OF ACIDIC DECOMPOSITION OF POLPINO PHOSPHORITE

The deficiency and growing price of phosphate fertilizers are becoming a major problem in Russia. Most of more than 200 proved phosphorite deposits have enough recourse to exploit them but processing the ore from these deposits presents severe difficulties, and it can’t be effectively implemented at this moment. The result of the decomposition process heavily depends on the origin of the ore, their chemical and mineralogical composition and other factors. Three types of phosphorites (carbonated, siliceous, and argillaceous) can be distinguished, and these types of phosphorites behave differently during the acidic decomposition, which leads to the differences in the conditions and performances in the process of their treatment. Phosphorite from Polpino deposit can be considered poor with total component content P2O5≈15.3%, and by the level of SiO2 it can be qualified as siliceous type. The stock from this deposit is highly reactive because of the carbonated additions and its mineral structure. The aim of the research is to study the dynamics of particle shape and size change during the acidic decomposition of a representative quartered sample of Polpino phosphorite. The decomposition was performed using nitric acid with temporary inhibition of the reaction at 0, 10, 30, 60, 300, 600 seconds by neutralization of acid with potassium hydroxide. Solid phase behavior was investigated using microscopic analysis (scanning electronic microscopy) with multi-purpose module microscope JEOL JSM-6510, and then obtained micrographs were edited with special software. Analysis of the behavior of the particles shows that their total number was nearly constant for each experiment, and the number of particles for every fraction almost didn’t change in time. This leads to assumption that the phosphate component in phosphorite from Polpino deposit is located inside of the porous alpha-quartz. It was determined that alpha-quartz from the phosphorite forms a matrix structure and doesn’t undergo changes, and its pore size doesn’t prevent acidic extraction of calcium and phosphate from the inner volume.Forcitation:Pochitalkina I.A., Kondakov D.F., Syromyatnikov A.S., Makaev S.V. Investigation of solid phase behavior during process of acidic decomposition of polpino phosphorite. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 10. P. 47-52