Cultivation of Edible Tropical Bolete, Phlebopus spongiosus, in Thailand and Yield Improvement by High-Voltage Pulsed Stimulation

Tropical bolete, Phlebopus spongiosus, is an edible ectomycorrhizal mushroom indigenous to northern Thailand. This mushroom has the ability to produce fruiting bodies without the need for a host plant. In this study, the technological cultivation of P. spongiosus was developed. Cultivation experiments indicated that fungal mycelia could completely colonize the cultivation substrate over a period of 85–90 days following inoculation of liquid inoculum. Primordia were induced under lower temperatures, high humidity and a 12-h photoperiod. Mature fruiting bodies were developed from young fruiting bodies within a period of one week. Consequently, yield improvement of P. spongiosus cultivation was determined by high-voltage pulsed stimulation. The results indicated that the highest degree of primordial formation, number of mature fruiting bodies and total weight values were obtained in cultivation experiments involving a high voltage of 40 kV. The total weight of the mushrooms increased by 1.4 times after applying high-voltage pulses when compared with the control. Additionally, the results revealed that the size of the fruiting body and the proximate composition of the fruiting bodies from high-voltage stimulation treatments were not different from the control. This research provides valuable information concerning successful cultivation techniques and yield improvement by high-voltage pulsed stimulation for the large-scale commercial fruiting body production of P. spongiosus.

Mapping the Endogenous Ketogenic System Across Ages, Sex and Diets

Understanding how our cells maintain energy homeostasis has long been a focus of aging biology. A decline in energy metabolism is central to many age-related diseases such as Alzheimer’s disease, heart failure, frailty, and delirium. Intervening on pathways involved in energy homeostasis can extend healthy lifespan. When our primary energy substrate glucose, is scarce, our bodies use ketone bodies (i.e. beta-hydroxybutyrate, acetoacetate, acetone). Aging is associated with glucose intolerance and insulin insensitivity, yet what role ketone body metabolism might play in compensating for impaired glucose utilization in age-related diseases is understudied. Here, we investigated how the body’s endogenous ketone body production and utilization pathways are modulated by age across the lifespan of female and male C57BL/6 mice (4 mo old, 12 mo old, 22 mo old). We show how different ages have different metabolic and gene expression responses to 1-week ketogenic diet (KD) or ketone ester diet. We observed an apparently compensatory ketogenic response in older animals fed normal diet, with a stronger compensatory response driven by KD. We observed tissue-specific changes, including induction of ketone body production enzymes in the aging heart. When comparing the ketogenic capacity between sexes, females had a higher basal level and less variation with age, underscoring the importance of sexual dimorphism in metabolism. Overall, these findings suggest that older animals use ketone bodies to meet energetic demands in a normal diet context. This study supports the potential roles of ketogenic therapies such as exogenous ketones to improve energy homeostasis in conditions of aging.

Artificial cultivation of a novel wild strain of Lepista sordida (Sowerby) Pat from south west China

A novel wild strain of Lepista sordida mushroom was collected from a soybean field in Liujiaba at Dazhou district of south western area of China in 2015.The morphological description and molecular identification were conducted to confirm the species. In the present study, optimization was carried out from mycelial growth and fruit body production. For DAAS-E70, the best growth rate was obtained using yeast malt extract, pH 6.0 and temperature 25°C. The wheat grain mushroom spawn was used for upscaling of the mycelium to be used for fruiting body production. In the field experiments, the average biological efficiency of DAAS-E70 was higher than that of Jilin-1, in which, DAAS-E70 accounting for 41.22% of the average biological efficiency, while the Jilin-1 was 35.02%. The stable biological efficiency of DAAS-E70 in different environments and seasons showed that the DAAS-E70 could be used for its commercial cultivation and could provide a new reference for its artificial domestication. Bangladesh J. Bot. 50(3): 813-818, 2021 (September) Special

Metabolic Responses to Energy-Depleted Conditions

Dietary intervention is one of the most important approaches for the treatment of metabolic diseases such as diabetes mellitus. Fasting and caloric restriction have profound effects on systemic metabolism. The energy source-producing organs, such as the liver, and peripheral tissues rewire their metabolism to meet the energy demands of the whole body. Glycogenolysis, fatty acid oxidation, and ketone body production are characteristic metabolic changes that occur during fasting and caloric restriction. These metabolic changes are regulated by various signaling cascades including PPARα and FGF21. Moderate fasting and caloric restriction have also been implicated in extending the lifespan in a variety of organisms from nematodes to vertebrates. Intensive research has unveiled several regulatory mechanisms of longevity including metabolic regulators such as mTOR and sirtuins. The epigenome has been attracting attention as a mechanism underlying metabolic diseases and longevity. The epigenome is the concept that involves covalent modifications of DNA, histones, and RNA, which are mediated by the action of epigenetic enzymes. The activity of these enzymes is regulated by energy states, i.e. metabolites including ketone bodies and intermediates of various metabolic pathways. Thus, energy states are recorded in cells as an epigenetic memory, which may cause future onset of metabolic diseases and affect lifespan.

Chromium Doped UO2-Based Ceramics: Synthesis and Characterization of Model Materials for Modern Nuclear Fuels

Cr-doped UO2 as a modern nuclear fuel type has been demonstrated to increase the in-reactor fuel performance compared to conventional nuclear fuels. Little is known about the long-term stability of spent Cr-doped UO2 nuclear fuels in a deep geological disposal facility. The investigation of suitable model materials in a step wise bottom-up approach can provide insights into the corrosion behavior of spent Cr-doped nuclear fuels. Here, we present new wet chemical approaches providing the basis for such model systems, namely co-precipitation and wet coating. Both were successfully tested and optimized, based on detailed analyses of all synthesis steps and parameters: Cr-doping method, thermal treatment, reduction of U3O8 to UO2, green body production, and pellet sintering. Both methods enable the production of suitable model systems with a similar microstructure and density as a reference sample from AREVA. In comparison with results from the classical powder route, similar trends upon grain size and lattice parameter were determined. The results of this investigation highlight the significance of subtly different synthesis routes on the properties of Cr-doped UO2 ceramics. They enable a reproducible tailor-made well-defined microstructure, a homogeneous doping, for example, with lanthanides or alpha sources, the introduction of metallic particles, and a dust-free preparation.

Association between Fasting Ketonuria and Advanced Liver Fibrosis in Non-Alcoholic Fatty Liver Disease Patients without Prediabetes and Diabetes Mellitus

Ketone body production, an alternative fuel upon low glucose availability, reduces hepatic fat accumulation. However, its clinical implications have not been established in patients with nonalcoholic fatty liver disease (NAFLD). We investigated the association between spontaneous fasting ketonuria and liver fibrosis in patients with NAFLD without prediabetes and diabetes mellitus (DM). A total of 6202 patients with ultrasound confirmed NAFLD without prediabetes and DM were enrolled in the study. Using low cut off values of NAFLD fibrosis score (NFS) and fibrosis-4, liver fibrosis was defined as an intermediate–high probability of advanced liver fibrosis. Of the 6202 NAFLD patients, 360 (5.8%) had ketonuria. Compared to the patients without ketonuria, patients with ketonuria were younger (41.1 vs. 44.6 years, p < 0.001), had lower levels of glucose (87.2 vs. 91.0 mg/dL, p < 0.001), and homeostatic model assessment for insulin resistance (1.0 vs. 1.5, p < 0.001). The presence of ketonuria had an inverse association with liver fibrosis, assessed using both NFS (final adjusted odds ratio [aOR], 0.67; 95% confidence interval [CI], 0.45–1.01) and fibrosis-4 (aOR, 0.58; 95% CI, 0.40–0.84). The presence of ketonuria in NAFLD patients without prediabetes and DM may have favorable metabolic effects compared to the absence of ketonuria, independent of traditional metabolic factors.

Succession and potential role of bacterial communities during Pleurotus ostreatus production

ABSTRACT There is an increasing interest in studying bacterial-fungal interactions (BFIs), also the interactions of Pleurotus ostreatus, a model white-rot fungus and important cultivated mushroom. In Europe, P. ostreatus is produced on a wheat straw-based substrate with a characteristic bacterial community, where P. ostreatus is exposed to the microbiome during substrate colonisation. This study investigated how the bacterial community structure was affected by the introduction of P. ostreatus into the mature substrate. Based on the results obtained, the effect of the presence and absence of this microbiome on P. ostreatus production in an experimental cultivation setup was determined. 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and amplicon sequencing revealed a definite succession of the microbiome during substrate colonisation and fruiting body production: a sharp decrease in relative abundance of Thermus spp. and Actinobacteria, and the increasing dominance of Bacillales and Halomonas spp. The introduced experimental cultivation setup proved the protective role of the microbial community against competing fungi without affecting P. ostreatus growth. We could also demonstrate that this effect could be attributed to both living microbes and their secreted metabolites. These findings highlight the importance of bacterial-fungal interactions during mushroom production.

β-hydroxybutyrate accumulates in the rat heart during low-flow ischaemia with implications for functional recovery

Extrahepatic tissues which oxidise ketone bodies also have the capacity to accumulate them under particular conditions. We hypothesised that acetyl-coenzyme A (acetyl-CoA) accumulation and altered redox status during low-flow ischaemia would support ketone body production in the heart. Combining a Langendorff heart model of low-flow ischaemia/reperfusion with liquid chromatography coupled tandem mass spectrometry (LC-MS/MS), we show that β-hydroxybutyrate (β-OHB) accumulated in the ischaemic heart to 23.9 nmol/gww and was secreted into the coronary effluent. Sodium oxamate, a lactate dehydrogenase (LDH) inhibitor, increased ischaemic β-OHB levels 5.3-fold and slowed contractile recovery. Inhibition of β-hydroxy-β-methylglutaryl (HMG)-CoA synthase (HMGCS2) with hymeglusin lowered ischaemic β-OHB accumulation by 40%, despite increased flux through succinyl-CoA-3-oxaloacid CoA transferase (SCOT), resulting in greater contractile recovery. Hymeglusin also protected cardiac mitochondrial respiratory capacity during ischaemia/reperfusion. In conclusion, net ketone generation occurs in the heart under conditions of low-flow ischaemia. The process is driven by flux through both HMGCS2 and SCOT, and impacts on cardiac functional recovery from ischaemia/reperfusion.

Metabolic Changes of Hepatocytes in NAFLD

Nonalcoholic fatty liver disease (NAFLD) is often accompanied by systemic metabolic disorders such as hyperglycemia, insulin resistance, and obesity. The relationship between NAFLD and systemic metabolic disorders has been well reviewed before, however, the metabolic changes that occur in hepatocyte itself have not been discussed. In NAFLD, many metabolic pathways have undergone significant changes in hepatocyte, such as enhanced glycolysis, gluconeogenesis, lactate production, tricarboxylic acid (TCA) cycle, and decreased ketone body production, mitochondrial respiration, and adenosine triphosphate (ATP) synthesis, which play a role in compensating or exacerbating disease progression, and there is close and complex interaction existed between these metabolic pathways. Among them, some metabolic pathways can be the potential therapeutic targets for NAFLD. A detailed summary of the metabolic characteristics of hepatocytes in the context of NAFLD helps us better understand the pathogenesis and outcomes of the disease.

Pseudomonas aeruginosa PA14 produces R-bodies, extendable protein polymers with roles in host colonization and virulence

R-bodies are long, extendable protein polymers formed in the cytoplasm of some bacteria; they are best known for their role in killing of paramecia by bacterial endosymbionts. Pseudomonas aeruginosa PA14, an opportunistic pathogen of diverse hosts, contains genes (referred to as the reb cluster) with potential to confer production of R-bodies and that have been implicated in virulence. Here, we show that products of the PA14 reb cluster associate with R-bodies and control stochastic expression of R-body structural genes. PA14 expresses reb genes during colonization of plant and nematode hosts, and R-body production is required for full virulence in nematodes. Analyses of nematode ribosome content and immune response indicate that P. aeruginosa R-bodies act via a mechanism involving ribosome cleavage and translational inhibition. Our observations provide insight into the biology of R-body production and its consequences during P. aeruginosa infection.