Bckdk-Mediated Branch Chain Amino Acid Metabolism Reprogramming Contributes to Muscle Atrophy during Cancer Cachexia.

SCOPE: Branched chain amino acids (BCAAs) are essential amino acids and important nutrient signals for energy and protein supplementation. The study uses muscle-specific branched-chain α-keto acid dehydrogenase kinase (Bckdk) conditional knockout (cKO) mice to reveal the contribution of BCAA metabolic dysfunction to muscle wasting. METHOD AND RESULTS: Muscle-specific Bckdk-cKO mice are generated through crossbreeding of Bckdkf/f mice with Myf5Cre mice. Lewis lung cancer (LLC) tumor transplantation is used to establish the cancer cachexia model. The occurrence of cancer cachexia is accelerated in the muscle-specific Bckdk-cKO mice after bearing LLC tumor. Wasting skeletal muscle is characterized by increased protein ubiquitination degradation and impaired protein synthesis. The wasting muscle gastrocnemius is mechanized as a distinct BCAA metabolic dysfunction. Based on the atrophy phenotype resulting from BCAA metabolism dysfunction, the optimized BCAA supplementation improves the survival of cancer cachexia in muscle-specific Bckdk-cKO mice bearing LLC tumors, and improves the occurrence of cancer cachexia. The mechanism of BCAA supplementation on muscle mass preservation is based on the promotion of protein synthesis and the inhibition of protein ubiquitination degradation. CONCLUSIONS: Dysfunctional BCAA metabolism contributes to the inhibition of protein synthesis and increases protein degradation in the cancer cachexia model of muscle-specific Bckdk-cKO mice bearing LLC tumors. The reprogramming of BCAA catabolism exerts therapeutic effects by stimulating protein synthesis and inhibiting protein degradation in skeletal muscle.

Isolation, Identification and Characteristic Analysis of Plant Endophyte Electrogenic Bacteria Shinella zoogloeoides SHE10.

Electroactive microorganisms play a significant role in microbial fuel cells (MFCs). These devices are environmentally friendly and can turn large quantities of organic material into renewable energy based on microbial diversity. Based on broad microbial diversity, it is necessary to obtain a comprehensive understanding of their resource distribution and to discover potential resources. In this study, sweet potato tissues were selected to isolate endophytic bacteria, and the electrochemical activity potential of those bacteria was evaluated by high-throughput screening with a WO3 nanoprobe. This study was screened and obtained a strain SHE10 with electrochemical performance from the rhizome of sweet potato by a WO3 nanoprobe, which was identified as Shinella zoogloeoides. After nearly 600 h of voltage monitoring and cyclic voltammetry analysis, the results showed that the average voltage of S. zoogloeoides SHE10 reached 122.5 mV in stationary period. The maximum power density is 78.3 ± 1.8 mW/m2, and the corresponding current density is 223.0 mA/m2. The good redox reaction also indicated that the strain had good electrical activity. Its electron transfer mode was diverse, but its power generation mechanism still needs to be further discussed. The study of S. zoogloeoides SHE10 provides scientific theoretical reference for expanding the resource pool of electroproducing bacteria and the types of electroproducing microorganisms.

The inhibitory effect of volatile organic compounds produced by Bacillus subtilis CL2 on pathogenic fungi of wolfberry.

Bacillus subtilis strain CL2 is antagonistic to wolfberry postharvest pathogenic fungi. In this study, we isolated and screened this strain for in vitro experiments. The result of the two-sealed-base-plates method revealed that volatile organic compounds (VOCs) emitted from the strain CL2 inhibited the hyphal growth of four pathogenic fungi Mucor circinelloides LB1, Fusarium arcuatisporum LB5, Alternaria iridiaustralis LB7, and Colletotrichum fioriniae LB8. After exposure to VOCs for 5 days, the hyphal growth of the pathogen C. fioriniae LB8 was inhibited by 73%. Scanning electron microscopy revealed that the VOCs produced by B. subtilis CL2 caused the mycelium morphology of the pathogenic fungi to deform, twist, fold, and shrink. In the in vivo experiments, we noticed that VOCs could significantly reduce the weight loss rate of wolfberry fruits caused by the pathogenic fungus M. circinelloides LB1 and that the decay incidence rate were caused by the pathogenic fungi F. arcuatisporum LB5, A. iridiaustralis LB7, and C. fioriniae LB8. On the basis of the headspace-gas chromatography-ion mobility spectrometry analysis, seven VOCs produced by strain CL2 were identified. Among them, 2,3-butanedione and 3-methylbutyric acid are the main antifungal active substances. This study investigated the antifungal properties of VOCs produced by the strain CL2 on postharvest pathogenic fungi isolated from wolfberry fruits both in vivo and in vitro, thereby providing the theoretical basis for its future applications.

A potentially important resource: endophytic yeasts.

Recent advancements in the research on endophytes isolated from plants and crops have greatly broadened its application in various fields. Endophytic bacteria and endophytic fungi are known to promote the growth of various plants. Besides, the secondary metabolites such as alcohol and xylitol secreted by the endophytic yeast also help their hosts to resist microbial invasion. This makes them a potential substitute for chemical-based control methods. Moreover, the plant hosts can also provide nutrients for the growth of endophytic yeasts. To achieve the symbiotic relationship, yeasts must colonize most parts of the plant tissues, including intercellular spaces, cytoplasm, stomata of seeds, roots, stems, leaves, and fruits as well. Conventionally, isolation of endophytic yeasts from different plant tissues and understanding their interior plants colonization mechanism have remainedkey strategies to exploit their key potentials. In this review, we will elaborate on the diversity, characteristics of colonization, and the factors that influence the distribution of endophytic yeasts. This review also lays a theoretical foundation for the application of endophytic yeasts in various industrial and agricultural practices.