Microbial mechanisms for higher hydrogen production in anaerobic digestion at constant temperature versus gradient heating.

BACKGROUND: Clean energy hydrogen (H2) produced from abundant lignocellulose is an alternative to fossil energy. As an essential influencing factor, there is a lack of comparison between constant temperatures (35, 55 and 65 °C) and gradient heating temperature (35 to 65 °C) on the H2 production regulation potential from lignocellulose-rich straw via high-solid anaerobic digestion (HS-AD). More importantly, the microbial mechanism of temperature regulating H2 accumulation needs to be investigated. RESULTS: Constant 65 °C led to the lowest lignin residue (1.93%) and the maximum release of cellulose and hemicellulose, and the highest H2 production (26.01 mL/g VS). H2 production at 35 and 55 °C was only 14.56 and 24.13 mL/g VS, respectively. In order to further explore the potential of ultra-high temperature (65 °C), HS-AD was performed by gradient heating conditions (35 to 65 °C). However, compared to constant 65 °C, gradient heating conditions led to higher lignin residue (2.49%) and lower H2 production (13.53 mL/g VS) than gradient heating conditions (47.98%). In addition, metagenomic analysis showed the cellulose/hemicellulose hydrolyzing bacteria and genes (mainly Thermoclostridium, and xynA, xynB, abfA, bglB and xynD), H2-producing bacteria and related genes (mainly Thermoclostridium, and nifD, nifH and nifK), and microbial movement and metabolic functions were enriched at 65 °C. However, the enrichment of two-component systems under gradient heating conditions resulted in a lack of highly-enriched ultra-high-temperature cellulose/hemicellulose hydrolyzing genera and related genes but rather enriched H2 consumption genera and genes (mainly Acetivibrio, and hyaB and hyaA) resulting in a weaker H2 production. CONCLUSIONS: The lignin degradation process does not directly determine H2 accumulation, which was actually regulated by bacteria/genes contributing to H2 production/consumption. In addition, it is temperature that enhances the hydrolysis process of lignin rather than lignin-degrading enzymes, bacteria and genes by promoting microbial material transfer and metabolism. In terms of temperature, one of the key parameters of HS-AD for H2 production, we developed an important regulatory strategy, enriched the theoretical basis of temperature regulation for H2 production to further expanded the research horizon in this field. Video Abstract.

Injectable, degradable, and mechanically adaptive hydrogel induced by L-serine and allyl-functionalized chitosan with platelet-rich plasma for treating intrauterine adhesions.

The integration of barrier materials with pharmacological therapy is a promising strategy to treat intrauterine adhesions (IUAs). However, most of these materials are surgically implanted in a fixed shape and incongruence with the natural mechanical properties of the uterus, causing poor adaptability and significant discomfort to the patients. Herein, an injectable, biodegradable, and mechanically adaptive hydrogel loaded with platelet-rich plasma (PRP) is created by L­serine and allyl functionalized chitosan (ACS) to achieve efficient, comfortable, and minimally invasive treatment of IUAs. L­serine induces fast gelation and mechanical reinforcement of the hydrogel, while ACS introduces, imparting a good injectability and complaint yet strong feature to the hydrogel. This design enables the hydrogel to adapt to the complex geometry and match the mechanical properties of the uterine. Moreover, the hydrogel exhibits proper degradability, sustained growth factors (GFs) of PRP release ability, and good biocompatibility. Consequently, the hydrogel shows promising therapeutic efficacy by reducing collagen fiber deposition and facilitating endometrium cell proliferation, thereby restoring the fertility function of the uterus in an IUAs model of rats. Accordingly, the combination of L­serine and ACS-induced hydrogel with such advantages holds great potential for treating IUAs. STATEMENT OF SIGNIFICANCE: This research introduces a breakthrough in the treatment of intrauterine adhesions (IUAs) with an injectable, biodegradable and mechanically adaptive hydrogel using L­serine and allyl functionalized chitosan (ACS). Unlike traditional surgical treatments, this hydrogel uniquely conforms to the uterus's geometry and mechanical properties, offering a minimally invasive, comfortable, and more effective solution. The hydrogel is designed to release growth factors from platelet-rich plasma (PRP) sustainably, promoting tissue regeneration by enhancing collagen fiber deposition and endometrium cell proliferation. Demonstrated efficacy in a rat model of IUAs indicates its great potential to significantly improve fertility restoration treatments. This advancement represents a significant leap in reproductive medicine, promising to transform IUAs treatment with its innovative approach to achieving efficient, comfortable, and minimally invasive therapy.

Injectable, stable, and biodegradable hydrogel with platelet-rich plasma induced by l-serine and sodium alginate for effective treatment of intrauterine adhesions.

The combination of pharmacological and physical barrier therapy is a highly promising strategy for treating intrauterine adhesions (IUAs), but there lacks a suitable scaffold that integrates good injectability, proper mechanical stability and degradability, excellent biocompatibility, and non-toxic, non-rejection therapeutic agents. To address this, a novel injectable, degradable hydrogel composed of poly(ethylene glycol) diacrylate (PEGDA), sodium alginate (SA), and l-serine, and loaded with platelet-rich plasma (PRP) (referred to as PSL-PRP) is developed for treating IUAs. l-Serine induces rapid gelation within 1 min and enhances the mechanical properties of the hydrogel, while degradable SA provides the hydrogel with strength, toughness, and appropriate degradation capabilities. As a result, the hydrogel exhibits an excellent scaffold for sustained release of growth factors in PRP and serves as an effective physical barrier. In vivo testing using a rat model of IUAs demonstrates that in situ injection of the PSL-PRP hydrogel significantly reduces fibrosis and promotes endometrial regeneration, ultimately leading to fertility restoration. The combined advantages make the PSL-PRP hydrogel very promising in IUAs therapy and in preventing adhesions in other internal tissue wounds.

Amino acid-induced rapid gelation and mechanical reinforcement of hydrogels with low-hysteresis and self-recoverable and fatigue-resistant properties.

Hydrogels with rapid gelation ability and robust mechanical properties are highly desirable for nascent applications in biomedical, wearable electronic, industrial and agricultural fields. However, current rapid-gelation hydrogels are compromised by poor mechanical properties, complex design of precursor molecular structures and limited precursor species. Herein, we propose a facile and universal strategy to achieve rapid gelation, strengthening and toughening of free-radical polymerized hydrogels by introducing cheap and accessible amino acids. Amino acids not only activate persulfate to quickly produce free radicals and thus induce fast free radical polymerization, but also can form strong hydrogen bonds with the network chains to strengthen and toughen the hydrogels. For example, with the presence of L-serine, the acrylamide (AM) monomer shows rapid gelation within tens of seconds, and moreover the resulting hydrogel reaches a tensile strength of 0.45 MPa and a breaking strain of 2060%. More importantly, owing to the extremely dynamic feature of the hydrogen bonds between L-serine molecules and network chains, the hydrogel possesses the advantages of low hysteresis, rapid self-recovery capability and outstanding fatigue resistance. Furthermore, this strategy is general to a wide range of amino acids and monomers. We also demonstrate that this rapid, controllable and universal strategy for the fabrication of mechanically robust hydrogels holds tremendous potential for diverse practical applications, such as flexible electronic sensors and ultraviolet (UV)-blocking artificial skins.

First Report of Powdery Mildew Caused by Podosphaera xanthii on Glandularia tenera in China.

Glandularia tenera (syn. Verbena tenera) is an herbaceous perennial ornamental plant used in gardens as an edging plant with beautiful white, red, or purple flowers. In autumn 2020 and 2021, severe powdery mildew infection was observed on G. tenera cultivar Xianghe in Renming Botanical garden in Shangqiu, Henan province, China (34.4568° N, 115.6640° E). Approximately 80% of leaves on each plant were symptomatic, and about 90% of the plants were infected. Powdery mildew colonies appeared as white spots on the adaxial surface of the leaves and stems of the plants in the initial infection stage. Later, mycelial growth was amphigenous, thick, forming irregular white patches, and effused to cover the whole leaf surface. Finally, leaves turned yellow and senescence occurred. Samples of symptomatic leaves were stained with trypan blue and examined under a Leica DM2500 microscope. Microscopic observations showed that conidia on infected leaves were hyaline and ellipsoid to oval with fibrosin bodies, measured 25 to 37 × 14 to 23 µm with a length/width ratio of 1.4 to 2.0. Conidiophores were unbranched, straight, 80 to 210× 10 to 14 µm in size, and produced two to five immature conidia in chains. Foot cells of conidiophores were cylindrical with slight constrictions at basal septa, and followed by one to three short cells. Fungal hyphae were septate, branched, and flexuous to straight and 4 to 7µm wide with indistinct to slightly nipple-shaped appressoria. Chasmothecia were not observed. These morphological characteristics were identical with the previous description of Podosphaera xanthii (Castagne) U. Braun & Shishkoff (Braun and Cook 2012). To confirm the identification, the sequence of ITS1-5.8s-ITS2 region of rDNA for the isolate SQVT was amplified from conidia collected from infected leaves with universal primers ITS1 and ITS4, sequenced and analyzed using the BLASTn search of GenBank. Amplicon was 565 bp (OM293967) and showed 99.82% similarity with sequence of P. xanthii from Eclipta prostrate (MT260063) in China (Xu et al. 2020), from Youngia denticulate (AB040351) in Japan (Hirata et al. 2000), and 99.65% with sequence of P. xanthii from V. brasiliensis in Korea (Cho et al. 2014). The domains D1 and D2 of the 28S rDNA for the isolate SQVTPX-1 was amplified with primer NL1/NL4. Amplicon was 613 bp (ON259308) and showed 100% similarity with sequence of P. xanthii from V. brasiliensis (AB936277) (Meeboon and Takamatsu, 2015). Pathogenicity tests were conducted by gently pressing the infected leaves onto leaves of five healthy G. tenera cultivar Xianghe plants. Five non-inoculated plants served as controls. Plants were maintained in a greenhouse at 25 ± 2°C. Eight days after inoculation, symptoms similar to those observed under natural conditions developed on the inoculated leaves of G. tenera plants, whereas the control plants remained symptomless. The fungus on inoculated leaves was morphologically identical to that first observed in the field. P. xanthii is a cosmopolitan powdery mildew fungus, parasitic on numerous plant species, especially Cucurbitaceae and Compositae plants. The pathogen has been reported infecting V. bonariensis (Hong et al. 2021), V. × hybrida in China (Zhuang 2005), and V. brasiliensis in Korea (Cho et al. 2014). Interestingly, G. tenera plants infected by P. xanthii were adjacent with V. × hybrida plants infected by P. xanthii in Renming Botanical garden. Incidence of P. xanthii on G. tenera add information on pathogen's host range and help us develop comprehensive survey and effective management of the disease. To our knowledge, this is the first report of P. xanthii on G. tenera in China (Farr and Rossman 2021). Braun, U., and Cook, R. T. A. 2012. Taxonomic Manual of the Erysiphales (Powdery Mildews). CBS Biodiversity Series No. 11. CBS, Utrecht, the Netherlands. Cho, S. E., et al. 2014. Plant Dis. 98: 1159. Farr, D. F., and Rossman, A. Y. 2021. Fungal Databases, Syst. Mycol. Microbiol. Lab., ARS, USDA. Hong, Q. Q., et al. 2021. Plant Dis. 105: 3297. Hirata, T., et al. 2000. Can. J. Bot. 78: 1521-1530. Meeboon, J. and Takamatsu, S. 2015. Mycoscience . 56: 243-251. Xu, D. D., et al. 2020. Plant Dis. 104: 3263. Zhuang, W. Y. 2005. Fungi of northwestern China. Mycotaxon, Ltd., Ithaca, NY.

RNA m6A methylation participates in regulation of postnatal development of the mouse cerebellum.

BACKGROUND: N6-methyladenosine (m6A) is an important epitranscriptomic mark with high abundance in the brain. Recently, it has been found to be involved in the regulation of memory formation and mammalian cortical neurogenesis. However, while it is now established that m6A methylation occurs in a spatially restricted manner, its functions in specific brain regions still await elucidation. RESULTS: We identify widespread and dynamic RNA m6A methylation in the developing mouse cerebellum and further uncover distinct features of continuous and temporal-specific m6A methylation across the four postnatal developmental processes. Temporal-specific m6A peaks from P7 to P60 exhibit remarkable changes in their distribution patterns along the mRNA transcripts. We also show spatiotemporal-specific expression of m6A writers METTL3, METTL14, and WTAP and erasers ALKBH5 and FTO in the mouse cerebellum. Ectopic expression of METTL3 mediated by lentivirus infection leads to disorganized structure of both Purkinje and glial cells. In addition, under hypobaric hypoxia exposure, Alkbh5-deletion causes abnormal cell proliferation and differentiation in the cerebellum through disturbing the balance of RNA m6A methylation in different cell fate determination genes. Notably, nuclear export of the hypermethylated RNAs is enhanced in the cerebellum of Alkbh5-deficient mice exposed to hypobaric hypoxia. CONCLUSIONS: Together, our findings provide strong evidence that RNA m6A methylation is controlled in a precise spatiotemporal manner and participates in the regulation of postnatal development of the mouse cerebellum.

Region-specific RNA m6A methylation represents a new layer of control in the gene regulatory network in the mouse brain.

N6-methyladenosine (m6A) is the most abundant epitranscriptomic mark found on mRNA and has important roles in various physiological processes. Despite the relatively high m6A levels in the brain, its potential functions in the brain remain largely unexplored. We performed a transcriptome-wide methylation analysis using the mouse brain to depict its region-specific methylation profile. RNA methylation levels in mouse cerebellum are generally higher than those in the cerebral cortex. Heterogeneity of RNA methylation exists across different brain regions and different types of neural cells including the mRNAs to be methylated, their methylation levels and methylation site selection. Common and region-specific methylation have different preferences for methylation site selection and thereby different impacts on their biological functions. In addition, high methylation levels of fragile X mental retardation protein (FMRP) target mRNAs suggest that m6A methylation is likely to be used for selective recognition of target mRNAs by FMRP in the synapse. Overall, we provide a region-specific map of RNA m6A methylation and characterize the distinct features of specific and common methylation in mouse cerebellum and cerebral cortex. Our results imply that RNA m6A methylation is a newly identified element in the region-specific gene regulatory network in the mouse brain.