Heat Shock Pretreatment Research Articles

Investigating the microbial community dynamics in biohydrogen production from palm oil mill effluent (POME) with molasses addition under mesophilic condition

Recently, there has been a surge in global demand for hydrogen as a sustainable and carbon dioxide-free energy carrier. As hydrogen is derived from biological processes, biohydrogen is gaining attention from economic and environmental perspectives because it can be produced from waste, such as palm oil mill effluent (POME). As a country with the largest palm oil industry in the world, Indonesia has the potential to utilize POME as a fermentation substrate for biohydrogen production. This study used local indigenous microorganisms from POME anaerobic pond sludge to produce biohydrogen. The experiment was conducted in an anaerobic batch fermenter under dark fermentation. Screening at initial pH and molasses addition were optimized to obtain the optimal fermentation substrate. A urea addition and heat shock pretreatment were compared to understand the relationship between biohydrogen production, COD reduction representing substrate value, and microbial community dynamics. As in field application, anaerobic process conditions were adjusted at the mesophilic temperature. The importance of comprehending what kind of microorganisms played a role in a consortium was analyzed by the 16S rRNA V3–V4 region using a next-generation sequencing (NGS) approach. Heat pretreatment exhibited the number of bacterial taxa order Thermoanaerobacterales increased significantly in direct proportion to the biohydrogen, up to 24.07% of the total volume gas produced. Notwithstanding, the mesophilic production process altered the microbial community, with Clostridiales as the predominant bacteria group, followed by Lactobacillales, Oscillospirales, and Lachnospirales. Understanding the dynamics and physiochemicals of the microbial community that affect microbial growth is targeted to improve biohydrogen production.

Efficient bio-hydrogen production by dark co-fermentation of food-rich municipal solid waste and urban pruning wastes of pine, cypress, and berry

Bio-hydrogen (bio-H2) production from dark co-fermentation of pruning wastes, from pine, cypress, and berry trees, and food-rich municipal solid waste (FMSW) was evaluated as a promising way to combine waste management and renewable energy production. The inoculum was initially optimized by heat-shock pretreatment at 65, 75, 85, and 95 ℃ for 15, 30, and 45 min to maximize bio-H2 yields. The optimum pretreatment conditions (75 °C for 45 min) were applied for dark co-fermentation analyses. The highest bio-H2 production yield of 84 ± 6 mL/g VS was obtained by dark co-fermentation of 20 g/L pruning wastes and FMSW under initially neutral conditions. The fermentation of individual substrates led to 40.9, 0.2, 0.1, and 0.2 mL/g VS from FMSW, pine, berry, and cypress, respectively, 85% lower than that obtained through dark co-fermentation. Therefore, co-processing of a “stiff substrate”, lignocellulose, with a “loose part”, starchy FMSW, leads to a higher bio-H2 yield. Dark co-fermentation led to the bio-conversion of more than 76% of starch, 31% of glucan, and 41% of hemicellulose, besides 41% lignin removal. The modified Gompertz model (MGM) and Logistic model (MLM) were well-fitted on kinetic data (with R2 values ≥0.98), and the kinetic parameters were calculated.

Model biological systems demonstrate the inducibility of pathways that strongly reduce cryoprotectant toxicity

Cryoprotectant toxicity is a limiting factor for the cryopreservation of many living systems. We were moved to address this problem by the potential of organ vitrification to relieve the severe shortage of viable donor organs available for human transplantation. The M22 vitrification solution is presently the only solution that has enabled the vitrification and subsequent transplantation with survival of large mammalian organs, but its toxicity remains an obstacle to organ stockpiling for transplantation. We therefore undertook a series of exploratory studies to identify potential pretreatment interventions that might reduce the toxic effects of M22. Hormesis, in which a living system becomes more resistant to toxic stress after prior subtoxic exposure to a related stress, was investigated as a potential remedy for M22 toxicity in yeast, in the nematode worm C. elegans, and in mouse kidney slices. In yeast, heat shock pretreatment increased survival by 18-fold after exposure to formamide and by over 9-fold after exposure to M22 at 30 °C; at 0 °C and with two-step addition, treatment with 90% M22 resulted in 100% yeast survival. In nematodes, surveying a panel of pretreatment interventions revealed 3 that conferred nearly total protection from acute whole-worm M22-induced damage. One of these protective pretreatments (exposure to hydrogen peroxide) was applied to mouse kidney slices in vitro and was found to strongly protect nuclear and plasma membrane integrity in both cortical and medullary renal cells exposed to 75–100% M22 at room temperature for 40 min. These studies demonstrate for the first time that endogenous cellular defenses, conserved from yeast to mammals, can be marshalled to substantially ameliorate the toxic effects of one of the most toxic single cryoprotectants and the toxicity of the most concentrated vitrification solution so far described for whole organs.

Extracellular vesicles ameliorates sleep deprivation induced anxiety-like behavior and cognitive impairment in mice

The aim of this research was to explore the therapeutic capabilities of extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) that had been subjectedto heat shock pretreatment, in treating psychiatric disorders induced by sleep deprivation in mice. The EVs were isolated and characterized, while western blotting was utilized to assess the expression of exosomal markers and heat shock protein 70 (HSP70). To evaluate the impact of EV treatment on anxiety-like behavior and cognitive impairment in sleep-deprived (SD) mice, the open field test, plus maze test, and Y-maze task were conducted. Heat shock pretreatment significantly increased the expression of HSP70 in EVs. Administration of EVs fromheat shock-pretreated hUC-MSCs improved anxiety-like behavior and cognitive function in SD mice. Furthermore, EV treatment promoted synaptic protein expression, HSP70 expression and inhibited neuroinflammation in the hippocampus of SD mice. Western blotting analysis also revealed that EV treatment reduced the levels of TLR4 and p65 in the hippocampus. EVs from heat shock-pretreated hUC-MSCs have therapeutic potential for sleep deprivation-induced psychiatric disorders by regulating neuroinflammation and synaptic function in mice.

Enhancing acidification efficiency of vegetable wastes through heat shock pretreatment and initial pH regulation.

Anaerobic digestion (AD) technology is a practical approach to alleviate severe environmental issues caused by vegetable wastes (VWs). However, its primary product is methane-rich biogas converted from the precursors (mainly volatile fatty acids, VFAs) after long fermentation periods, making traditional AD projects of low economic profits. Intervening in the methanogenesis stage artificially to produce high value-added VFAs can shorten the reaction time of the AD process and significantly improve profits, posing a promising alternative for treating VWs. Given this, this study applied heat shock (HS) pretreatment to inoculum to prevent methane production during AD and systemically investigated the effects of HS pretreatment and initial pH regulation on VFA production from VWs. The results showed that appropriate HS pretreatment effectively inhibited methane generation but promoted VFA accumulation, and VFA production was further enhanced by adjusting the initial pH to 8.0 and 9.0. The highest total VFA concentration of 14,883 mg/L witha VFA yield of 496.1 mg/gVS, 26.98% higher than that of the untreated group, was achieved at an initial pH 8.0 with HS pretreatment of 80 °C for 1 h. Moreover, pH regulation influenced the metabolic pathway of VFA production from VWs during AD, as butyrate was the dominant product at an initial pH of 6.0, while the increased initial pH improved the acetate proportion.

Heat shock pretreatment and low temperature fluctuation cold storage maintains flesh quality and retards watercore dissipation of watercored 'Fuji' apples

Watercored apples have a unique flavor and particular flesh morphology. However, watercored apples are subject to loss of water core, browning, and softening during postharvest storage. In this study, heat shock pretreatment, hot air (HA) or hot water (HW), was combined with low temperature fluctuation (LTF) cold storage to delay the disappearance of the water cores and the flesh browning and softening during a 120 d storage. The apples were evaluated for appearance characteristics, texture parameters, enzyme activities, reactive oxygen content, membrane lipid oxidation degree, tissue microstructure, and cell morphology during the storage period. The results showed that HW combined with LTF was most effective in maintaining the visual quality and texture quality of watercored apples compared with other treatments and the control. Moreover, HW-LTF could effectively inhibit the accumulation of malondialdehyde (MDA), retard the increase of electrolyte leakage (EL), reduce the membrane lipid peroxidation, and maintain the tissue microstructure and cell morphology. Meanwhile, HW-LTF inhibited the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) and reduced the degree of flesh browning. Therefore, the HW-LTF is of guiding significance for the cold storage of watercored apples.

A Novel: Low-cost Method for the Isolation of Anaerobic Hydrogen Producing Bacteria

The hydrogen content of the two sludge samples namely TDS and PLS were increased after the heat shock pretreatment from 239.23 ± 10.23 mL/L to 663.87 ± 15.99 mL/L at 80°C and from 173.61 ± 17.21 mL/L to 496.74 ± 30.21 mL/L at 60°C, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) indicated that Enterococcus and Clostridium were the dominant bacteria in the TDS and PLS consortium. Two strains were successfully isolated from TDS and PLS using a simple method. Based on Bergey’s key identification and 16S rDNA sequencing, they were identified as Clostridium butyricum strain TD and Clostridium acetobutylicum strain PL. The hydrogen content, glucose consumed yield, and hydrogen yield of C. butyricum TD and C. acetobutylicum PL were 545.24 ± 7.31 mL/L, 90 ± 0.41 %, 0.89 ± 0.01 mol H2/mol glucose, and 729.34 ± 22.81 mL/L, 92.77 ± 1.39 %, 1.26 ± 0.05 mol H2/mol glucose, respectively.

Effect of static magnetic field exposure on biohydrogen production via dark fermentation of glucose

The effect of a static magnetic field (SMF) on the microbial activity of anaerobic granular sludge was investigated using a SMF field provided by a magnetic platform with intensities between 30 and 90 mT. BioH2 production was assessed in fed batch fermentation tests from glucose using anaerobic granular sludge with (HT) and without (WHT) heat shock pretreatment (100 ºC, 1 h). Under the conditions tested, 70 mT SMF was the best condition for bioH2 production, with a threefold decrease of lag time, a 12–50% increase in bioH2 production rate, and an improved consumption of iron and phosphate, compared to the controls (no SMF). Exposure to the SMF induced modifications in volatile fatty acid (VFA) production, pH and conductivity, biomass concentration, exopolysaccharide (EPS) composition as well as size and settleability of the granular anaerobic sludge. Microbial analysis showed that in the presence of the SMF, the relative abundance (RA) of Clostridium and Lactobacillus increased in both HT and WHT sludges, while it decreased the RA of Methanosaeta and Methanobacterium. The RA of Terrisporobacter increased with the heat shock, and also the stimulation along the fed batch cycles improved the RA of Terrisporobacter with and without SMF. The application of the SMF as a pre-treatment of inoculum and during bioH2 production seems to be an interesting and easy scaling up strategy to shorten the start-up of the dark fermentation process and help reducing the microbial diversity of the sludge, favouring more specialized species for bioH2 production.

Salinity pretreatment synergies heat shock toxicity in cyanobacterium Anabaena PCC7120.

This study was undertaken to bridge the knowledge gap pertaining to cyanobacteria's response to pretreatment. The result elucidates the synergistic effect of pretreatment toxicity in cyanobacterium Anabaena PCC7120 on morphological and biochemical attributes. Chemical (salt) and physical (heat) stress-pretreated cells exhibited significant and reproducible changes in terms of growth pattern, morphology, pigments, lipid peroxidation, and antioxidant activity. Salinity pretreatment showed more than a five-fold decrease in the phycocyanin content but a six-fold and five-fold increase in carotenoid, lipid peroxidation (MDA content), and antioxidant activity (SOD and CAT) at 1 h and on 3rd day of treatment, respectively, giving the impression of stress-induced free radicals that are scavenged by antioxidants when compared to heat shock pretreatment. Furthermore, quantitative analysis of transcript (qRT-PCR) for FeSOD and MnSOD displayed a 3.6- and 1.8-fold increase in salt-pretreated (S-H) samples. The upregulation of transcript corresponding to salt pretreatment suggests a toxic role of salinity in synergizing heat shock. However, heat pretreatment suggests a protective role in mitigating salt toxicity. It could be inferred that pretreatment enhances the deleterious effect. However, it further showed that salinity (chemical stress) augments the damaging effect of heat shock (physical stress) more profoundly than physical stress on chemical stress possibly by modulating redox balance via activation of antioxidant responses. Our study reveals that upon pretreatment of heat, the negative effect of salt can be mitigated in filamentous cyanobacteria, thus providing a foundation for improved cyanobacterial tolerance to salt stress.

Prussian Blue Nanoparticle-Entrapped GelMA Gels Laden with Mesenchymal Stem Cells as Prospective Biomaterials for Pelvic Floor Tissue Repair.

Pelvic organ prolapse (POP) seriously affects elderly patients' quality of life, and new repair materials are urgently needed. To solve this problem, we synthesized methacrylated gelatin (GelMA) hydrogels and incorporated photothermally active Prussian blue nanoparticles (PBNPs) to synthesize PBNP@GelMA. Then, MSCs were encapsulated in the PBNP@GelMA and exposed to a 1.0 W/cm2 of 808 nm laser for 10 min to perform heat shock pretreatment for the implantation of mesenchymal stem cells (MSCs). Next, we tested the repair efficacy of scaffold-cell complexes both in vitro and in vivo. Our results reveal that the heat shock treatment induced by PBNP@GelMA improved the viability of MSCs, and the underlying mechanism may be related to HSP70. Furthermore, 2 weeks after implantation in the SD rat model, the collagen content increased in the MSC implantation group and PBNP@GelMA implantation group. However, the muscle regeneration at the implanting position was mostly enhanced after the implantation of the heat-shock-pretreated MSCs, which illustrates that heat shock treatment can further promote the MSC-mediated muscle regeneration. Therefore, manipulating the cell environment and providing proper heat stimulus by using PBNP@GelMA with NIR is a novel strategy to enhance the regenerative potential of MSCs and to promote pelvic tissue repair.

Assessing Different Inoculum Treatments for Improved Production of Hydrogen through Dark Fermentation

Hydrogen gas (H2) is an energy carrier that does not generate carbon dioxide emissions during combustion, but several processes in use for its production demand high energy inputs associated with fossil fuels and greenhouse emissions. Biological processes, such as dark fermentation (DF), have the potential to remove the dependency on fossil fuels in H2 production. DF is a process that encourages fermentative bacteria to ferment organic substrates to produce H2 as a truly clean energy carrier, but its success depends on removing the presence of competing H2−consuming microorganisms in the inoculum consortia. This paper addresses a strategy to enhance H2 production from different types of substrates by testing inoculum pre-treatment processes to inactivate H2−consuming bacteria, including acid-shock (pH 3), basic-shock (pH 10) and heat-shock (115 °C) methods. Digestate from anaerobic digesters processing sewage sludge was used to produce pre-treated inocula, which were subsequently tested in a batch bio-H2 potential (BHP) test using glucose as a substrate. The results show that heat-shock pre-treatment was the best method, reporting a H2 yield of 191.8 mL-H2/gVS added (the untreated inoculum reported 170.91 mL-H2/gVS added). Glucose conversion data show a high concentration of butyric acid in both treated and untreated inocula during BHP tests, which indicate that the butyrate pathway for H2 production was dominant; shifting this to the formate route could further enhance net H2 production. A standardised inoculum-conditioning method can help to consistently assess the biohydrogen potential of suitable feedstock for DF and maximise H2 yields.

CO2 conversion to volatile fatty acids by anaerobic granular sludge and Mg0

Platform chemicals (VFAs) production through CO2 utilization technologies plays a crucial role in international efforts for climate change mitigation. In this study, a new approach for sustainable and eco-friendly CO2 bioconversion to acetic acid proposed using 4 g L−1 magnesium ribbon (Mg0) in-situ and homoacetogen-enriched anaerobic granular sludge. To suppress methanogenesis three inhibition strategies were investigated. The use of NaCl (50, 70, 90 g L−1), 2-bromoethanesulfonate (4 mM BES), and a short heat-shock pre-treatment were applied to anaerobic granular sludge. The most effective strategy for methanogenesis inhibition and acetic acid production was the thermal treatment producing 2023,07 mg L−1 of acetic acid after 32 days (Cycle 7) with a maximum production rate of 234,58 mg L−1 day−1 at cycle 3 (after 14 days). Following the system with BES producing 1369,45 mg L−1 of acetic acid with a maximum production rate of 111,76 mg L−1 day−1 at cycle 3. The systems exposed to NaCl generated fewer VFAs compared to the other two systems (BES, Heat-shock). After the third cycle and until the end of the experiment (cycle 7), at the two systems (BES, Heat-shock), the acetic acid production rate slightly increased, whereas the methane significantly increased. At the end of cycle 7, the hydrogenotrophic methanogens Methanolinea was found in a high relative abundance and hydrogenotrophic methanogens acted antagonistically towards homoacetogens.

Biohydrogen production potential with sulfate and nitrate removal by heat-pretreated enriched sulfate-reducing microorganisms-based bioelectrochemical system.

In this study, heat-pretreated sulfate-reducing bacteria (SRBs) were evaluated for simultaneous sulfate and nitrate removal in a bioelectrochemical system (BES). The effect of the applied potential of 20mV to SRBs was evaluated at a sulfate concentration of 3g/L and/or nitrate concentration of 0.5g/L supplemented before heat pretreatment for sulfate and nitrate removal. The highest H2 production of 2.24 ± 0.04mM/L in heat-pretreated culture was observed in the presence of sulfate at an applied potential of 20mV (BHE-S). Simultaneous reduction of sulfate and nitrate was significant in BESs supplemented with either sulfate or nitrate during heat-shock pretreatment of the culture. The highest SO42- removal of 88.91 ± 0.8% was found in culture heat pretreated with NO3- and applied with 20mV potential (BHE-N). The kinetics of heat-pretreated culture showed higher R2 and ultimate potential for H2 on the continuous application of 20mV potential.

Exosomes derived from heat shock preconditioned bone marrow mesenchymal stem cells alleviate cisplatin-induced ototoxicity in mice

NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome contributes to the development of cisplatin-induced ototoxicity. Whether heat shock pretreatment could be utilized to up-regulate 70 kilodalton heat shock proteins (HSP70) expression in bone marrow mesenchymal stem cells (BMSCs)-derived exosomes (HS-BMSC-Exo) to alleviate cisplatin-induced ototoxicity is deciphered in this study. Heat shock pretreatment was performed on BMSCs to induce HS-BMSC-Exo, which were further trans-tympanically administrated into cisplatin intraperitoneally injected C57BL/6 mice. Auditory brainstem response (ABR) was assessed to indicate auditory sensitivity at 8, 16, 24, and 32 kHz. Myosin 7a staining was utilized to detect the mature hair cells. The relative expressions of the NLRP3 inflammasome complex were determined with Western blot in the cochlea. Diminished auditory sensitivity and increased hair cell loss could be observed in the cisplatin exposed mice with increased content of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, NLRP3, ASC, cleaved caspase-1, and pro-caspase-1, and decreased content of IL-10, which could be reversed by HS-BMSC-Exo or BMSC-Exo administration. It was worth noting that HS-BMSC-Exo demonstrated more treatment benefits than BMSC-Exo in cisplatin-induced ototoxicity. Heat shock precondition may provide a new therapeutic option to produce exosomal HSP70, and HS-BMSC-Exo could be utilized to relieve cisplatin-induced ototoxicity.

Global DNA Methylation and mRNA-miRNA Variations Activated by Heat Shock Boost Early Microspore Embryogenesis in Cabbage (Brassica oleracea).

Microspore culture, a type of haploid breeding, is extensively used in the cultivation of cruciferous crops such as cabbage. Heat shock (HS) treatment is essential to improve the embryo rate during the culture process; however, its molecular role in boosting early microspore embryogenesis (ME) remains unknown. Here we combined DNA methylation levels, miRNAs, and transcriptome profiles in isolated microspores of cabbage ‘01-88’ under HS (32 °C for 24 h) and normal temperature (25 °C for 24 h) to investigate the regulatory roles of DNA methylation and miRNA in early ME. Global methylation levels were significantly different in the two pre-treatments, and 508 differentially methylated regions (DMRs) were identified; 59.92% of DMRs were correlated with transcripts, and 39.43% of miRNA locus were associated with methylation levels. Significantly, the association analysis revealed that 31 differentially expressed genes (DEGs) were targeted by methylation and miRNA and were mainly involved in the reactive oxygen species (ROS) response and abscisic acid (ABA) signaling, indicating that HS induced DNA methylation, and miRNA might affect ME by influencing ROS and ABA. This study revealed that DNA methylation and miRNA interfered with ME by modulating key genes and pathways, which could broaden our understanding of the molecular regulation of ME induced by HS pre-treatment.

Selective enrichment of mixed consortia towards enhanced 1,3-Propanediol production from glycerol

Glycerol fermentation using mixed consortia leads to the production of several bio-products such as 1,3-Propanediol (1,3-PDO), acetate, lactate, ethanol, butyrate, propionate and biogas. Increasing production specificity majorly of 1,3-PDO in glycerol fermentation was assessed by suppressing 1,3-PDO non-producing microbial communities. Dual pretreatment (selective enrichment) strategy employing heat-shock and 2-bromoethanesulfonic acid (BESA) was implemented to enhance 1,3-PDO productivity. Additionally, Vitamin B12 (Vit. B12) was supplemented for improving fermentation efficiency considering its role in glycerol fermentation. 1,3-PDO (9.3 ± 0.51 g/L; 0.64 mol1,3-PDO/molGly_con) was the major product from 20 g/L glycerol in the system (RHHBVS) operated with combining enrichment strategy and Vit. B12 supplementation compared to control (RHHS) system (5.56 ± 0.26 g/L; 0.48 mol1,3-PDO/molGly_con) operated solely with the heat-shock pretreatment strategy. Acetate was major co-metabolite in all the systems and highest was observed with RHHBVS (1.45 ± 0.72 g/L) system. The results supported the positive impact of selective enrichment strategy (dual pretreatment of inoculum) towards the enhanced 1,3-PDO production.

Influence of a heat-shock pre-treatment on wound-induced phenolic biosynthesis as an alternative strategy towards fresh-cut carrot processing.

In fresh-cut vegetables, plant tissues are often challenged by (a)biotic stresses that act in combination, and the response to combinatorial stresses differs from that triggered by each individually. Phenolic induction by wounding is a known response contributing to increase products phenolic content. Heat application is a promising treatment in minimal processing, and its interference on the wound-induced response is produce-dependent. In carrot, two-combined stress effects were evaluated: peel removal vs. shredding, and heat application (100 °C/45 s) vs. shredding, on changes in total phenolic content (TPC) during 10 days (5 °C). By applying the first stress combination, a decrease in TPC was verified on day 0 (∼50%), ascribed to the high phenolic content of peels. Recovery of initial fresh carrot levels was achieved after 7 days owing to phenolic biosynthesis induced by shredding. For the second combination, changes in TPC, phenylalanine-ammonia-lyase (PAL), and peroxidase (POD) activity of untreated (Ctr) and heat-treated (HS) peeled shredded carrot samples were evaluated during 10 days. The heat-shock did not suppress phenolic biosynthesis promoted by PAL, although there was a two-day delay in TPC increments. Notwithstanding, phenolic accumulation after 10 days exceeded raw material TPC content. Also, the decrease in POD activity (30%) could influence quality degradation during storage.

Heat shock preconditioning mesenchymal stem cells attenuate acute lung injury via reducing NLRP3 inflammasome activation in macrophages

ObjectivesAcute lung injury (ALI) remains a common cause of morbidity and mortality worldwide, and to date, there is no effective treatment for ALI. Previous studies have revealed that topical administration of mesenchymal stem cells (MSCs) can attenuate the pathological changes in experimental acute lung injury. Heat shock (HS) pretreatment has been identified as a method to enhance the survival and function of cells. The present study aimed to assess whether HS-pretreated MSCs could enhance immunomodulation and recovery from ALI.Materials and methodsHS pretreatment was performed at 42 °C for 1 h, and changes in biological characteristics and secretion functions were detected. In an in vivo mouse model of ALI, we intranasally administered pretreated umbilical cord-derived MSCs (UC-MSCs), confirmed their therapeutic effects, and detected the phenotypes of the macrophages in bronchoalveolar lavage fluid (BALF). To elucidate the underlying mechanisms, we cocultured pretreated UC-MSCs with macrophages in vitro, and the expression levels of inflammasome-related proteins in the macrophages were assessed.ResultsThe data showed that UC-MSCs did not exhibit significant changes in viability or biological characteristics after HS pretreatment. The administration of HS-pretreated UC-MSCs to the ALI model improved the pathological changes and lung damage-related indexes, reduced the proinflammatory cytokine levels, and modulated the M1/M2 macrophage balance. Mechanistically, both the in vivo and in vitro studies demonstrated that HS pretreatment enhanced the protein level of HSP70 in UC-MSCs, which negatively modulated NLR family pyrin domain containing 3 (NLRP3) inflammasome activation in alveolar macrophages. These effects were partially reversed by knocking down HSP70 expression.ConclusionHS pretreatment can enhance the beneficial effects of UC-MSCs in inhibiting NLRP3 inflammasome activation in macrophages during ALI. The mechanism may be related to the upregulated expression of HSP70.Graphical abstract

The effect of mono- and multiple fermentation parameters on volatile fatty acids (VFAs) production from chicken manure via anaerobic digestion

Although the high nitrogen content of chicken manure (CM) poses major challenges for methane production through anaerobic digestion, on the bright side, it has a great potential for production of value-added intermediate products, such as volatile fatty acids (VFAs). However, in order to enhance VFAs yield, methane formation should be substantially suppressed. In the current research, individual and multiple effects of initial pH, heat-shock pretreatment, chemical methanogens inhibitor and the inoculum to substrate ratio (ISR) on optimization VFAs fermentation from CM were evaluated via batch assays. In this regard, the highest net VFAs yield, 0.53 g-VFA/g-VS, was achieved at conditions with heat-shocked inoculum and CM at ISR 1:6 and pH uncontrolled. Acetate dominated the VFAs mixture, accounting for up to 75% of total. Increased inoculum content enhanced the bioconversion efficiency to 78% at ISR 1:3. The study results suggest that alkalinity is a key promoter of VFAs production from CM.

Evaluation of Heat Shock-Induced Stress Tolerance to Some Abiotic Factors in Barley Seedlings by Chlorophyll a Fluorescence Technique

In this study, the effect of heat shock pretreatment on the occurence of cross tolerance to heat, salinity, drought, and UV-B stress in three barley (Hordeum vulgare L.) cultivars (Bülbül-89, Tarm-92, and Tokak 157/37) was investigated through the chlorophyll a fluorescence technique. Heat stress increased Fo (minimum fluorescence) significantly when compared to the controls of these barley cultivars, but heat shock pretreatment led to lower Fo values in all cultivars. Fm (maximum fluorescence), Fv/Fm (maximum quantum efficiency of photosystem II) and PI (performance index) were significantly decreased in all barley cultivars subjected to heat stress. In Tarm-92, heat shock pretreatment caused higher Fm, Fv/Fm and PI values than heat stress alone. On the other hand, heat shock pretreatment decreased Fm, Fv/Fm and PI more drastically in Bülbül-89 and Tokak 157/37. As a consequence, changes in Fo, Fm, Fv/Fm and PI may be attributed to thermotolerance development in Tarm-92 as a result of heat shock pretreatment.