Diel transcriptional responses of coral-Symbiodiniaceae holobiont to elevated temperature.

Coral exhibits diel rhythms in behavior and gene transcription. However, the influence of elevated temperature, a key factor causing coral bleaching, on these rhythms remains poorly understood. To address this, we examined physiological, metabolic, and gene transcription oscillations in the Acropora tenuis-Cladocopium sp. holobiont under constant darkness (DD), light-dark cycle (LD), and LD with elevated temperature (HLD). Under LD, the values of photosystem II efficiency, reactive oxygen species leakage, and lipid peroxidation exhibited significant diel oscillations. These oscillations were further amplified during coral bleaching under HLD. Gene transcription analysis identified 24-hour rhythms for specific genes in both coral and Symbiodiniaceae under LD. Notably, these rhythms were disrupted in coral and shifted in Symbiodiniaceae under HLD. Importantly, we identified over 20 clock or clock-controlled genes in this holobiont. Specifically, we suggested CIPC (CLOCK-interacting pacemaker-like) gene as a core clock gene in coral. We observed that the transcription of two abundant rhythmic genes encoding glycoside hydrolases (CBM21) and heme-binding protein (SOUL) were dysregulated by elevated temperature. These findings indicate that elevated temperatures disrupt diel gene transcription rhythms in the coral-Symbiodiniaceae holobiont, affecting essential symbiosis processes, such as carbohydrate utilization and redox homeostasis. These disruptions may contribute to the thermal bleaching of coral.

Linking coral fluorescence phenotypes to thermal bleaching in the reef-building Galaxea fascicularis from the northern South China Sea.

Coral fluorescence phenotypes have been suggested as an adaptation to a broad range of environmental conditions, yet the mechanisms linking thermal bleaching tolerance in reef-building coral populations, associated with fluorescence phenotypes due to GFP-like proteins, remains unclear. In this study, the relationship between the thermal sensitivity and phenotypic plasticity of corals was investigated using two phenotypes of Galaxea fascicularis, green and brown. The results reveal that brown G. fascicularis was more susceptible to bleaching than green G. fascicularis when exposed to a higher growth temperature of 32 °C. Both phenotypes of G. fascicularis were associated with the thermotolerant Symbiodiniaceae symbiont, Durusdinium trenchii. However, the brown G. fascicularis showed a significant decrease in Symbiodiniaceae cell density and a significant increase in pathogenic bacteria abundance when the growth temperature was raised from 29 to 32 °C. The physiological traits and transcriptomic profiles of Symbiodiniaceae were not notably affected, but there were differences in the transcriptional levels of certain genes between the two phenotype hosts of G. fascicularis. Under heat stress of 32 °C, the gene encoding green fluorescent protein (GFP)-like and chromosome-associated proteins, as well as genes related to oxidative phosphorylation, cell growth and death showed lower transcriptional levels in the brown G. fascicularis compared to the green G. fascicularis. Overall, the results demonstrate that the green form of G. fascicularis is better able to tolerate ocean warming and defend against pathogenic bacteria, likely due to higher gene transcription levels and defense ability. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-023-00190-1.

Spatial and temporal evolution of urban resilience in China and analysis of barriers: Based on a sustainable development perspective.

With the increasing uncertainty of urban security, urban resilience construction with risk awareness and bottom-line thinking has become essential for promoting sustainable urban development. This paper measures China's urban resilience development index (CRDI) based on 284 cities in China (except Tibet) using the entropy method from four dimensions: economic, social, environmental, and infrastructure, and analyzes it by combining coupling coordination degree and barrier factor analysis. We find that: (1) At the national level, CRDI and its sub-dimensions show an increasing trend in time, a decreasing spatial layout from coastal to inland, and a "high-high-low-low" clustering feature in space. (2) At the regional level, the CRDI is from high to low in the east, middle, and west order. The sub-dimensions are from high to low in the order of east, middle, and west for economic, social, and infrastructure resilience and from high to low in the order of east, west, and middle for environmental resilience. (3) To coupling coordination degree, the CRDI index coupling coordination is increasing in time trend but is still on the verge of dissonance. (4) Social resilience is the main obstacle factor. In the indicator layer, human resources, innovation, education, security, living, and environmental protection are the areas where CRDI coordinated development is the key to improvement. Based on the above empirical evidence, this paper proposes countermeasures to optimize urban resilience construction from four perspectives: economic, social, environmental, and infrastructure.

Nicotinamide mononucleotide attenuates airway epithelial barrier dysfunction via inhibiting SIRT3 SUMOylation in asthma.

Nicotinamide adenine dinucleotide (NAD+) is an essential element in cellular metabolism that regulates fundamental biological processes. Growing evidence suggests that a decline in NAD+ is a common pathological factor in various diseases and aging. However, its role in airway epithelial barrier function in response to asthma remains underexplored. The current study aims to explore the efficacy of restoring cellular NAD+ concentration through supplementation with the NAD+ precursor, nicotinamide mononucleotide (NMN), in the treatment of allergic asthma and to investigate the role of SIRT3 in mediating the effects of NAD+ precursors. In this research, NMN alleviated airway inflammation and reduced mucus secretion in house dust mite (HDM)-induced asthmatic mice. It also mitigated airway epithelial barrier disruption in HDM-induced asthma in vitro and in vivo. But inhibition of SIRT3 expression abolished the effects of NMN. Mechanistically, HDM induced SIRT3 SUMOylation and proteasomal degradation. Mutation of these two SIRT3 SUMO modification sites enhanced the stability of SIRT3. Additionally, SIRT3 was targeted by SENP1 which acted to de-conjugate SUMO. And down-regulation of SENP1 expression in HDM-induced models was reversed by NMN. Collectively, these findings suggest that NMN attenuates airway epithelial barrier dysfunction via inhibiting SIRT3 SUMOylation in asthma. Blockage of SIRT3 SUMOylation emerges as for the treatment of allergic asthma.

Metabolic and immune costs balance during natural acclimation of corals in fluctuating environments.

Epigenetic modifications based on DNA methylation can rapidly improve the potential of corals to adapt to environmental pressures by increasing their phenotypic plasticity, a factor important for scleractinian corals to adapt to future global warming. However, the extent to which corals develop similar adaptive mechanisms and their specific adaptation processes remain unclear. Here, to reveal the regulatory mechanism by which DNA methylation improves thermal tolerance in Pocillopora damicornis under fluctuating environments, we analyzed genome-wide DNA methylation signatures in P. damicornis and compared the differences in the methylation and transcriptional responses of P. damicornis from fluctuating and stable environments using whole-genome bisulfite sequencing and nanopore-based RNA sequencingtranscriptome sequencing. We discovered low methylation levels in P. damicornis (average methylation 4.14%), with CpG accounting for 74.88%, CHH for 13.27%, and CHG for 11.85% of this methylation. However, methylation levels did not change between coral samples from the fluctuating and stable environments. The varied methylation levels in different regions of the gene revealed that the overall methylation level of the gene body was relatively high and showed a bimodal methylation pattern. Methylation occurs primarily in exons rather than introns within the gene body In P. damicornis, there was only a weak correlation between methylation and transcriptional changes at the individual gene level, and the methylation and gene expression levels generally exhibited a bell-shaped relationship, which we speculate may be due to the specificity of cnidarian species. Correlation analysis between methylation levels and the transcriptome revealed that the highest proportion of the top 20 enriched KEGG pathways was related to immunity. Additionally, P. damicornis collected from a high-temperature pool had a lower metabolic rate than those collected from a low-temperature pool. We hypothesize that the dynamic balance of energy-expenditure costs between immunity and metabolism is an important strategy for increasing P. damicornis tolerance. The fluctuating environment of high-temperature pools may increase the heat tolerance in corals by increasing their immunity and thus lowering their metabolism.

PM2.5-derived exosomal long noncoding RNA PAET participates in childhood asthma by enhancing DNA damage via m6A-dependent OXPHOS regulation.

Fine particulate matter (PM2.5) is known to enhance DNA damage levels and is involved in respiratory diseases. Exosomes can carry noncoding RNAs, especially long noncoding RNAs (lncRNAs), as regulators of DNA damage, which participate in diseases. However, their role in PM2.5-induced childhood asthma remains unclear. We performed RNA-seq to profile aberrantly expressed exosomal lncRNAs derived from PM2.5-treated human bronchial epithelial (HBE) cell models. The role of exosomal lncRNAs in childhood asthma was determined in a case-control study. The intercellular communication mechanisms of exosomal lncRNA on DNA damage were determined in vitro. Exosomes secreted by PM2.5-treated HBE cells (PM2.5-Exos) could increase the DNA damage levels of recipient HBE cells and promote the expression levels of airway remodeling-related markers in sensitive human bronchial smooth muscle cells (HBSMCs). LncRNA PM2.5-associated exosomal transcript (PAET) was highly expressed in PM2.5-Exos and was associated with PM2.5 exposure in childhood asthma. Mechanistically, exosomal lncRNA PAET promoted methyltransferase-like 3 (METTL3) accumulation by increasing its stability, which stimulated N6-methyladenosine (m6A) modification of cytochrome c oxidase subunit 4I1 (COX4I1), and COX4I1 levels were decreased in a mechanism dependent on the m6A "reader" YTH domain family 3 (YTHDF3). COX4I1 deficiency subsequently disrupted oxidative phosphorylation (OXPHOS), resulting in attenuated adenosine triphosphate (ATP) production and accumulation of reactive oxygen species (ROS), which increased DNA damage levels. This comprehensive study extends the understanding of PM2.5-induced childhood asthma via DNA damage and identifies exosomal lncRNA PAET as a potential target for childhood asthma.

0D Pyramid-intercalated 2D Bimetallic Halides with Tunable Electronic Structures and Enhanced Emission under Pressure.

Hybrid metal halides are emerging semiconductors as promising candidates for optoelectronics. The pursuit of hybridizing various dimensions of metal halides remains a desirable yet highly complex endeavor. By utilizing dimension engineering, a diverse array of new materials with intrinsically different electronic and optical properties has been developed. Here, we report a new family of 2D-0D hybrid bimetallic halides, (C6 N2 H14 )2 SbCdCl9 ⋅ 2H2 O (SbCd) and (C6 N2 H14 )2 SbCuCl9 ⋅ 2H2 O (SbCu). These compounds adopt a new layered structure, consisting of alternating 0D square pyramidal [SbCl5 ] and 2D inorganic layers sandwiched by organic layers. SbCd and SbCu have optical band gaps of 3.3 and 2.3 eV, respectively. These compounds exhibit weak photoluminescence (PL) at room temperature, and the PL gradually enhances with decreasing temperature. Density functional theory (DFT) calculations reveal that SbCd and SbCu are direct gap semiconductors, where first-principles band gaps follow the experimental trend. Moreover, given the different pressure responses of 0D and 2D components, these materials exhibit highly tunable electronic structures during compression, where a remarkable 11 times enhancement in PL emission is observed for SbCd at 19 GPa. This work opens new avenues for designing new layered bimetallic halides and further manipulating their structures and optoelectronic properties via pressure.

The diversity, community dynamics, and interactions of the microbiome in the world's deepest blue hole: insights into extreme environmental response patterns and tolerance of marine microorganisms.

IMPORTANCE: This study comprehensively examined the community dynamics, functional profiles, and interactions of the microbiome in the world's deepest blue hole. The findings revealed a positive correlation between the α-diversities of Symbiodiniaceae and archaea, indicating the potential reliance of Symbiodiniaceae on archaea in an extreme environment resulting from a partial niche overlap. The negative association between the α-diversity and ß-diversity of the bacterial community suggested that the change rule of the bacterial community was consistent with the Anna Karenina effects. The core microbiome comprised nine microbial taxa, highlighting their remarkable tolerance and adaptability to sharp environmental gradient variations. Bacteria and archaea played significant roles in carbon, nitrogen, and sulfur cycles, while fungi contributed to carbon metabolism. This study advanced our understanding of the community dynamics, response patterns, and resilience of microorganisms populating the world's deepest blue hole, thereby facilitating further ecological and evolutional exploration of microbiomes in diverse extreme environments.

Unfolding the secrets of microbiome (Symbiodiniaceae and bacteria) in cold-water coral.

Recent deep-ocean exploration has uncovered a variety of cold-water coral (CWC) ecosystems around the world ocean, but it remains unclear how microbiome is associated with these corals at a molecular levels. This study utilized metabarcoding, tissue section observation, and metatranscriptomes to investigate the microbiome (Symbiodiniaceae and bacteria) of CWC species (Narella versluysi, Heterogorgia uatumani, and Muriceides sp.) from depths ranging from 260 m to 370 m. Warm-water coral (WWC) species (Acropora pruinosa, Pocillopora damicornis, and Galaxea fascicularis) were used as control groups. Results revealed that CWC host diverse bacteria and Symbiodiniaceae cells were observed in endoderm of CWC tissues. Several new candidate bacterial phyla were found in both CWC and WWC, including Coralsanbacteria, Coralqiangbacteria, Coralgsqaceae, Coralgongineae, etc. Both the 16S rRNA gene sequencing and metatranscriptomes revealed that Actinobacteria and Proteobacteria were abundant bacterial phyla in CWC. At the gene transcription level, the CWC-associated Symbiodiniaceae community showed a low-level transcription of genes involved in photosynthesis, CO2 fixation, glycolysis, citric acid cycle, while bacteria associated with CWC exhibited a high-level transcription of genes for carbon fixation via the Wood-Lijungdahl pathway, short chain fatty acids production, nitrogen, and sulfur cycles. IMPORTANCE This study shed new light on the functions of both Symbiodiniaceae and bacteria in cold-water coral (CWC). The results demonstrated that Symbiodiniaceae can survive and actively transcribe genes in CWC, suggesting a possible symbiotic or parasitic relationship with the host. This study also revealed complete non-photosynthetic CO2 fixation pathway of bacteria in CWC, as well as their roles in short chain fatty acids production and assimilation of host-derived organic nitrogen and sulfur. These findings highlight the important role of bacteria in the carbon, nitrogen sulfur cycles in CWC, which were possibly crucial for CWC survival in in deep-water environments.

Adaptation strategies of relatively high-latitude marginal reef corals in response to severe temperature fluctuations.

The large seasonal temperature fluctuations caused by global warming and frequent marine heatwaves pose new challenges to survival of relatively high-latitude marginal reef corals. However, the adaptation strategies of high-latitude marginal corals are not fully understood. We employed integrated approach to investigate the response mechanism of hosts, Symbiodiniaceae, and symbiotic bacteria of marginal reef corals Acropora pruinosa and Pavona decussate in response to large seasonal temperature fluctuations. The coral holobiont maintained a high level of immunity to adapt to seasonal pressure by increasing Symbiodiniaceae energy supply. The symbiotic Symbiodiniaceae of two coral was dominated by C1 subgroup, and was stable across seasons. The α-diversity of symbiotic bacteria P. decussata and A. pruinosa in summer was higher than that in winter. The symbiotic bacterial community of two coral reorganized during different seasons. Scleractinian corals improve adaptability to seasonal stress by increasing energy supply to maintain high levels of immunity, increasing symbiotic bacterial α-diversity, and changing dominant bacteria. This study demonstrates the adaptation strategies of marginal reef corals to seasonal temperature fluctuations and provides novel insights into the study of the adaptation of corals and relatively high-latitude coral refuges in the context of global warming and intensified marine heatwaves.