AtPQT11, a P450 enzyme, detoxifies paraquat via N-demethylation

Paraquat is one of the most widely used nonselective herbicides in agriculture. Due to its wide use, paraquat resistant weeds have emerged and is becoming a potential threat to agriculture. The molecular mechanisms of paraquat resistance in weeds remain largely unknown. Physiological studies indicated that the impaired translocation of paraquat and enhanced antioxidation could improve paraquat resistance in plants. However, the detoxification of paraquat via active metabolism by plants has not been reported to date. Here we report that an activated expression of At1g01600 encoding the P450 protein CYP86A4 confers paraquat resistance as revealed by the gain-of-function mutant paraquat tolerance 11D (pqt11D), in which a T-DNA with four 35S enhancers was inserted at 1646 bp upstream the ATG of At1g01600. The paraquat resistance can be recapitulated in Arabidopsis wild type by overexpressing AtPQT11 (At1g01600), while its knockout mutant is hypersensitive to paraquat. Moreover, AtPQT11 also confers paraquat resistance in E. coli when overexpressed. We further demonstrate that AtPQT11 has P450 enzyme activity that converts paraquat to N-demethyl paraquat nontoxic to Arabidopsis, therefore detoxifying paraquat in plants. Taken together, our results unequivocally demonstrate that AtPQT11/ CYP86A4 detoxifies paraquat via active metabolism, thus revealing a novel molecular mechanism of paraquat resistance in plants and providing a means potentially enabling crops to resist paraquat.

The Biochemical and Clinical Perspectives of Lactate Dehydrogenase: An Enzyme of Active Metabolism

Background: Lactate dehydrogenase (LDH) is a group of oxidoreductase isoenzymes catalyzing the reversible reaction between pyruvate and lactate. The five isoforms of this enzyme, formed from two subunits, vary in isoelectric points and these isoforms have different substrate affinity, inhibition constants and electrophoretic mobility. These diverse biochemical properties play a key role in its cellular, tissue and organ specificity. Though LDH is predominantly present in the cytoplasm, it has a multi-organellar location as well. Objective: The primary objective of this review article is to provide an update in parallel, the previous and recent biochemical views and its clinical significance in different diseases. Methods: With the help of certain inhibitors, its active site three-dimensional view, reactions mechanisms and metabolic pathways have been sorted out to a greater extent. Overexpression of LDH in different cancers plays a principal role in anaerobic cellular metabolism, hence several inhibitors have been designed to employ as novel anticancer agents. Discussion: LDH performs a very important role in overall body metabolism and some signals can induce isoenzyme switching under certain circumstances, ensuring that the tissues consistently maintain adequate ATP supply. This enzyme also experiences some posttranslational modifications, to have diversified metabolic roles. Different toxicological and pathological complications damage various organs, which ultimately result in leakage of this enzyme in serum. Hence, unusual LDH isoform level in serum serves as a significant biomarker of different diseases. Conclusion: LDH is an important diagnostic biomarker for some common diseases like cancer, thyroid disorders, tuberculosis, etc. In general, LDH plays a key role in the clinical diagnosis of various common and rare diseases, as this enzyme has a prominent role in active metabolism.

Adaptive trade-offs in fish energetics and physiology: insights from adaptive differentiation among juvenile salmonids

Juveniles of different salmonid species often co-exist along environmental gradients, making them a useful model for identifying dominant trade-off axes and their stability within a biological hierarchy (e.g., from individuals to populations to species). In this perspective, we use multivariate trade-offs among juvenile coho salmon (Oncorhynchus kisutch) and rainbow trout (Oncorhynchus mykiss) as a case study to explore broader-scale patterns of trait association. Multivariate ordination identified a dominant trade-off axis between high growth, consumption, and growth efficiency versus high aerobic scope and active metabolism among individual juvenile rainbow trout and three ecologically divergent rainbow trout populations. This pattern suggests a dominant trade-off between growth and active metabolism among individuals and populations, facilitated by simple developmental controls on increased energy intake (larger digestive tract, potentially more risky foraging behavior). In contrast, the adaptive trade-off differentiating species appears to have shifted to maximizing growth and consumption (rainbow trout) versus maximizing growth efficiency (coho), based on evolved differences in foraging strategy and digestive physiology. The generality of these patterns remains uncertain, but trade-offs related to growth efficiency may be an underappreciated dimension of adaptive differentiation in fishes, and their relationship to digestive strategy and active metabolism warrants further investigation.

Contribution of Latex Micro Diagnosis to Modern Management of Rubber Plantations: Case of Clones With Low or Slow Metabolism PB 217 and PR 107

The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. Thus, in order to determine the best latex harvesting systems of clones with low or slow metabolism, six latex harvesting technologies are applied to them in a bulk statistical device from Fisher to four rehearsals. The rubber is tapped in downward half spiral stimulated or not for nine years after the opening of the tapping panel. The agronomic parameters (production, vegetative growth), the tapping panel dryness and those of the latex micro diagnosis were evaluated. The results indicate that these clones independently of the latex harvesting system have good rubber productivity (2310 kg.ha -1 .y-1 ) with good radial vegetative growth (2.9 cm.y -1 ). Their trees show a well-balanced physiological profile and an acceptable sensitivity to the tapping panel dryness (4.9%). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technologies "S/2 d3 6d/7 Pa1(1) ET2.5% 4/y, S/2 d4 6d/7 Pa1(1) ET2.5% 4/y and S/2 d4 6d/7 Pa1(1) ET2.5% 8/y” for the best. This index, favorably influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation.

Latex Micro Diagnosis, Modern Management Tool of Rubber Plantations of Clones With Active or Rapid Metabolism IRCA 18, IRCA 130, PB 235, PB 260 and PB 330

The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. Thus, in order to determine the best latex harvesting systems of clones with active or rapid metabolism (IRCA 18, IRCA 130, PB 235, PB 260 and PB 330), six latex harvesting technologies are applied to them in a bulk statistical device from Fisher to four rehearsals. The rubber is tapped in downward half spiral stimulated or not for nine years after the opening of the tapping panel. The agronomic parameters (production, vegetative growth), the tapping panel dryness and those of the latex micro diagnosis were evaluated. The results indicate that these clones independently of the latex harvesting system have good rubber productivity (2310 kg.ha -1.y1) with good radial vegetative growth (2.9 cm.y-1). Their trees show a wellbalanced physiological profile and an acceptable sensitivity to the tapping panel dryness (4.9%). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technologies “ S/2 d3 6d/7 Pa1(1) ET2.5% 4/y and S/2 d4 6d/7 Pa1(1) ET2.5% 4/y ” for the best. This index, favorably influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation.

Environmental Monitoring of Water Ecosystems Based on a New Microbiological Method

One of water ecosystems’ main components is heterotrophic bacterial plankton, carrying out processes of organic substance destruction that provides water ecosystems self-cleaning. The tasks facing modern environmental monitoring of water ecosystems demand the account not only the total number and number of separate physiological groups of bacteria, but also determination of quantity for microorganisms which are actively functioning during this time period. Now it is obvious that the results of bacterial plankton number and biomass determination received by direct account’s traditional methods don’t reflect quantity of the microorganisms which are really functioning and participating in biogeochemical cycles. The methods allowing carry out such researches based on use of special fluorescent dyes which are used as biochemical markers of various physiological processes proceeding in a bacterial cage. Results for application of a method for accounting of bacterial cages with active metabolism for marine and fresh-water ecosystems’ environmental monitoring have been presented. This method has been applied at researches of the microbial population in river, lake, estuarial, shelf marine ecosystems, and also in deepwater sea hollows for the purpose of actively functioning bacteria’ number determination. Respiratory activity markers use has shown that only an insignificant share (generally from 0.1 to 30 %, and in some cases — to 90 % of cages in the bacterial plankton’s total number) possesses the active metabolism and provides processes of organic substance destruction in water ecosystems. The received results testify to prospects for application of this microbiological method within environmental monitoring of water ecosystems for accounting of the bacterial plankton possessing active metabolism.