A study on the influence of perceived distance on China's inbound Tourism and the interaction of non-economic distance: An analysis of dynamic extended gravity model based on 61 countries' entry data (2004-2018).

In the post-epidemic era, the restart of China's inbound tourism is imminent. However, there are gaps in our current understanding of how distance perception dynamically affects inbound tourism in China. In order to understand the past patterns of inbound tourism in China, we mapped the data of 61 countries of origin from 2004 to 2018 into a dynamic expanding gravity model to understand the effects of cultural distance, institutional distance, geographical distance, and economic distance on inbound tourism in China and revealed the dynamic interaction mechanism of non-economic distance perception on inbound tourism in China. Our research results show that cultural distance has a positive impact on China's inbound tourism, while institutional distance has a negative impact. The significant finding is that the dynamic interaction of the above two kinds of perceived distance can still have a positive impact on China's inbound tourism. Its practical significance is that it can counteract the influence of institutional distance by strengthening the cultural distance. Generally speaking, geographical distance and institutional distance restrict China's inbound tourism flow, while cultural distance, economic distance, and interactive perceptual distance promote China's inbound tourism flow.

The Gradient Effect on Cyclic Behavior of 316L Stainless Steel in the Ultrasonic Bending Test.

Nanoindentation measurements were conducted to investigate the high-cycle response of 316L stainless steel in bending fatigue. Hardness variation owing to the gradient flexure stress amplitude for different curvatures was plotted along with the thickness and length, respectively. Scanning electron microscopy (SEM) was subsequently conducted to explore the deformation characteristics in multiple layers, which had cyclic gradient stress, on the cross-section of specimens. The nanoindentation results indicated that the cyclic hardening response of 316L stainless steel is correlated with the level of stress amplitude in the high-cycle fatigue (HCF) regime. Furthermore, an analytical model was proposed to clarify the relationship between nanohardness and stress amplitude. Finally, the evolution of damage accumulation due to irreversible plastic deformation is continuous during stress reduction up to the neighboring zone at the neutral surface of the flexure beam in some individual grains.

A gauge of coral physiology: re-examining temporal changes in Endozoicomonas abundance correlated with natural coral bleaching.

Bacteria contribute to many physiological functions of coral holobionts, including responses to bleaching. The bacterial genus, Endozoicomonas, dominates the microbial flora of many coral species and its abundance appears to be correlated with coral bleaching. However, evidences for decoupling of bleaching and Endozoicomonas abundance changes have also been reported. In 2020, a severe bleaching event was recorded at reefs in Taiwan, providing a unique opportunity to re-examine bleaching-Endozoicomonas association using multiple stony corals in natural environments. In this study, we monitored tissue color and microbiome changes in three coral species (Montipora sp., Porites sp., and Stylophora pistillata) in Kenting National Park, following the bleaching event. All tagged Montipora sp. and Porites sp. recovered from bleaching within 1 year, while high mortality occurred in S. pistillata. Microbiome analysis found no correlation of Endozoicomonas relative abundance and bleaching severity during the sampling period, but found a stronger correlation when the month in which bleaching occurred was excluded. Moreover, Endozoicomonas abundance increased during recovery months in Montipora sp. and Porites sp., whereas in S. pistillata it was nearly depleted. These results suggest that Endozoicomonas abundance may represent a gauge of coral health and reflect recovery of some corals from stress. Interestingly, even though different Endozoicomonas strains predominated in the three corals, these Endozoicomonas strains were also shared among coral taxa. Meanwhile, several Endozoicomonas strains showed secondary emergence during coral recovery, suggesting possible symbiont switching in Endozoicomonas. These findings indicate that it may be possible to introduce Endozoicomonas to non-native coral hosts as a coral probiotic.

Similar but different: Characterization of dddD gene-mediated DMSP metabolism among coral-associated Endozoicomonas.

Endozoicomonas are often predominant bacteria and prominently important in coral health. Their role in dimethylsulfoniopropionate (DMSP) degradation has been a subject of discussion for over a decade. A previous study found that Endozoicomonas degraded DMSP through the dddD pathway. This process releases dimethyl sulfide, which is vital for corals coping with thermal stress. However, little is known about the related gene regulation and metabolic abilities of DMSP metabolism in Endozoicomonadaceae. In this study, we isolated a novel Endozoicomonas DMSP degrader and observed a distinct DMSP metabolic trend in two phylogenetically close dddD-harboring Endozoicomonas species, confirmed genetically by comparative transcriptomic profiling and visualization of the change of DMSP stable isotopes in bacterial cells using nanoscale secondary ion spectrometry. Furthermore, we found that DMSP cleavage enzymes are ubiquitous in coral Endozoicomonas with a preference for having DddD lyase. We speculate that harboring DMSP degrading genes enables Endozoicomonas to successfully colonize various coral species across the globe.

Extraction and Surface Functionalization of Cellulose Nanocrystals from Sugarcane Bagasse.

The present study aimed to optimize the process for extracting cellulose nanocrystals (CNCs) from sugarcane bagasse through ultrasonic-assisted sulfuric acid hydrolysis and its subsequent modification with L-malic acid and silane coupling agent KH-550. The effects of the different modification methods and the order of modification on the structures and properties of bagasse CNCs were explored. The results indicated that the optimal process conditions were achieved at an acid-digestion temperature of 50 °C, a reaction time of 70 min, an ultrasonic power of 250 W, and a volume fraction of 55%. The modified CNCs were analyzed using infrared spectral, X-ray diffraction, and thermogravimetric techniques, which revealed that L-malic acid was attached to the hydroxyl group on the CNCs via ester bond formations, and the silane coupling agent KH-550 was adsorbed effectively on the CNCs' surfaces. Moreover, it was observed that the modification of the CNCs by L-malic acid and the KH-550 silane coupling agent occurred only on the surface, and the esterification-crosslinking modification method provided the best thermal stability. The performance of self-made CNC was found to be superior to that of purchased CNC based on the transmission electron microscopy analysis. Furthermore, the modified esterified-crosslinked CNCs exhibited the best structure and performance, thereby offering a potential avenue for the high-value utilization of sugarcane bagasse, a byproduct of sugarcane sugar production, and the expansion of the comprehensive utilization of sugarcane bagasse.

Bacterial Community Shifts during Polyp Bail-Out Induction in Pocillopora Corals.

Polyp bail-out constitutes both a stress response and an asexual reproductive strategy that potentially facilitates dispersal of some scleractinian corals, including several dominant reef-building taxa in the family Pocilloporidae. Recent studies have proposed that microorganisms may be involved in onset and progression of polyp bail-out. However, changes in the coral microbiome during polyp bail-out have not been investigated. In this study, we induced polyp bail-out in Pocillopora corals using hypersaline and hyperthermal methods. Bacterial community dynamics during bail-out induction were examined using the V5-V6 region of the 16S-rRNA gene. From 70 16S-rRNA gene libraries constructed from coral tissues, 1,980 OTUs were identified. Gammaproteobacteria and Alphaproteobacteria consistently constituted the dominant bacterial taxa in all coral tissue samples. Onset of polyp bail-out was characterized by increased relative abundance of Alphaproteobacteria and decreased abundance of Gammaproteobacteria in both induction experiments, with the shift being more prominent in response to elevated temperature than to elevated salinity. Four OTUs, affiliated with Thalassospira, Marisediminitalea, Rhodobacteraceae, and Myxococcales, showed concurrent abundance increases at the onset of polyp bail-out in both experiments, suggesting potential microbial causes of this coral stress response. IMPORTANCE Polyp bail-out represents both a stress response and an asexual reproductive strategy with significant implications for reshaping tropical coral reefs in response to global climate change. Although earlier studies have suggested that coral-associated microbiomes likely contribute to initiation of polyp bail-out in scleractinian corals, there have been no studies of coral microbiome shifts during polyp bail-out. In this study, we present the first investigation of changes in bacterial symbionts during two experiments in which polyp bail-out was induced by different environmental stressors. These results provide a background of coral microbiome dynamics during polyp bail-out development. Increases in abundance of Thalassospira, Marisediminitalea, Rhodobacteraceae, and Myxococcales that occurred in both experiments suggest that these bacteria are potential microbial causes of polyp bail-out, shedding light on the proximal triggering mechanism of this coral stress response.

Multiple Nucleocapsid Structural Forms of Shrimp White Spot Syndrome Virus Suggests a Novel Viral Morphogenetic Pathway.

White spot syndrome virus (WSSV) is a very large dsDNA virus. The accepted shape of the WSSV virion has been as ellipsoidal, with a tail-like extension. However, due to the scarcity of reliable references, the pathogenesis and morphogenesis of WSSV are not well understood. Here, we used transmission electron microscopy (TEM) and cryogenic electron microscopy (Cryo-EM) to address some knowledge gaps. We concluded that mature WSSV virions with a stout oval-like shape do not have tail-like extensions. Furthermore, there were two distinct ends in WSSV nucleocapsids: a portal cap and a closed base. A C14 symmetric structure of the WSSV nucleocapsid was also proposed, according to our Cryo-EM map. Immunoelectron microscopy (IEM) revealed that VP664 proteins, the main components of the 14 assembly units, form a ring-like architecture. Moreover, WSSV nucleocapsids were also observed to undergo unique helical dissociation. Based on these new results, we propose a novel morphogenetic pathway of WSSV.

Microbial mat compositions and localization patterns explain the virulence of black band disease in corals.

Black band disease (BBD) in corals is characterized by a distinctive, band-like microbial mat, which spreads across the tissues and often kills infected colonies. The microbial mat is dominated by cyanobacteria but also commonly contains sulfide-oxidizing bacteria (SOB), sulfate-reducing bacteria (SRB), and other microbes. The migration rate in BBD varies across different environmental conditions, including temperature, light, and pH. However, whether variations in the migration rates reflect differences in the microbial consortium within the BBD mat remains unknown. Here, we show that the micro-scale surface structure, bacterial composition, and spatial distribution differed across BBD lesions with different migration rates. The migration rate was positively correlated with the relative abundance of potential SOBs belonging to Arcobacteraceae localized in the middle layer within the mat and negatively correlated with the relative abundance of other potential SOBs belonging to Rhodobacteraceae. Our study highlights the microbial composition in BBD as an important determinant of virulence.

Cyclic Deformation and Fatigue Failure Mechanisms of Thermoplastic Polyurethane in High Cycle Fatigue.

In this study, the main purpose is to analyze the fatigue failure of thermoplastic polyurethane (TPU) plate under tension-tension load control tests (frequency = 5 Hz, stress ratio = 0.1) and consider the change in hydrogen bond content. The results show that the S-N curve of TPU material shows a downward trend before reaching the fatigue limit (10.25 MPa), and the energy is continuously consumed during the cyclic creep process and undergoes three stages of the hard segment and the soft segment changes. The infrared spectrum study shows that the increase in fatigue life will lead to more physical crosslinking, resulting in the reduction of hydrogen bond content, and the increase in microphase separation, leading to the occurrence of fatigue fracture. In addition, the scanning electron microscope and three-dimensional confocal analysis showed that the crack originated from the aggregation of micropores on the surface of the material and was accompanied by the slip of the molecular chain, the crack propagation direction was at an angle of about 45°.

Cellular mechanisms underlying extraordinary sulfide tolerance in a crustacean holobiont from hydrothermal vents.

The shallow-water hydrothermal vent system of Kueishan Island has been described as one of the world's most acidic and sulfide-rich marine habitats. The only recorded metazoan species living in the direct vicinity of the vents is Xenograpsus testudinatus, a brachyuran crab endemic to marine sulfide-rich vent systems. Despite the toxicity of hydrogen sulfide, X. testudinatus occupies an ecological niche in a sulfide-rich habitat, with the underlying detoxification mechanism remaining unknown. Using laboratory and field-based experiments, we characterized the gills of X. testudinatus that are the major site of sulfide detoxification. Here sulfide is oxidized to thiosulfate or bound to hypotaurine to generate the less toxic thiotaurine. Biochemical and molecular analyses demonstrated that the accumulation of thiosulfate and hypotaurine is mediated by the sodium-independent sulfate anion transporter (SLC26A11) and taurine transporter (Taut), which are expressed in gill epithelia. Histological and metagenomic analyses of gill tissues demonstrated a distinct bacterial signature dominated by Epsilonproteobacteria. Our results suggest that thiotaurine synthesized in gills is used by sulfide-oxidizing endo-symbiotic bacteria, creating an effective sulfide-buffering system. This work identified physiological mechanisms involving host-microbe interactions that support life of a metazoan in one of the most extreme environments on our planet.

High-Quality Genome Sequences of Two Octocoral-Associated Bacteria, Endozoicomonas euniceicola EF212T and Endozoicomonas gorgoniicola PS125T.

Endozoicomonas euniceicola EF212T and Endozoicomonas gorgoniicola PS125T were isolated from soft corals (Eunicea fusca and Plexaura sp., respectively) and sequenced using a PacBio Sequel IIe sequencer. This is the first report of the genome sequences of culturable octocoral-isolated Endozoicomonas strains.

Comparative genomic and transcriptomic analyses of trans-kingdom pathogen Fusarium solani species complex reveal degrees of compartmentalization.

BACKGROUND: The Fusarium solani species complex (FSSC) comprises fungal pathogens responsible for mortality in a diverse range of animals and plants, but their genome diversity and transcriptome responses in animal pathogenicity remain to be elucidated. We sequenced, assembled and annotated six chromosome-level FSSC clade 3 genomes of aquatic animal and plant host origins. We established a pathosystem and investigated the expression data of F. falciforme and F. keratoplasticum in Chinese softshell turtle (Pelodiscus sinensis) host. RESULTS: Comparative analyses between the FSSC genomes revealed a spectrum of conservation patterns in chromosomes categorised into three compartments: core, fast-core (FC), and lineage-specific (LS). LS chromosomes contribute to variations in genomes size, with up to 42.2% of variations between F. vanettenii strains. Each chromosome compartment varied in structural architectures, with FC and LS chromosomes contain higher proportions of repetitive elements with genes enriched in functions related to pathogenicity and niche expansion. We identified differences in both selection in the coding sequences and DNA methylation levels between genome features and chromosome compartments which suggest a multi-speed evolution that can be traced back to the last common ancestor of Fusarium. We further demonstrated that F. falciforme and F. keratoplasticum are opportunistic pathogens by inoculating P. sinensis eggs and identified differentially expressed genes also associated with plant pathogenicity. These included the most upregulated genes encoding the CFEM (Common in Fungal Extracellular Membrane) domain. CONCLUSIONS: The high-quality genome assemblies provided new insights into the evolution of FSSC chromosomes, which also serve as a resource for studies of fungal genome evolution and pathogenesis. This study also establishes an animal model for fungal pathogens of trans-kingdom hosts.

Soil Bacterial Community May Offer Solutions for Ginger Cultivation.

The Taitung region is one of Taiwan's main sites for ginger agriculture. Due to issues with disease and nutrients, farmers cannot use continuous cropping techniques on ginger, meaning that the ginger industry is constantly searching for new land. Continuous cropping increases the risk of infection by Pythium myriotylum and Ralstonia solanacearum, which cause soft rot disease and bacterial wilt, respectively. In addition, fertilizer additives, which are commonly used to increase trace elements in the soil, cannot restore the soil when it is undergoing continuous cropping on ginger, even when there has been no observable decrease in trace elements in the soil. Recent studies about soil microbiome manipulation and the application of microorganisms have shown that plant-associated microbes have the ability to improve plant growth and facilitate sustainable agriculture, but studies of this kind still need to be carried out on ginger cultivation. Therefore, in this study, we used the bacterial 16S V3-V4 hypervariable region of the 16S rRNA region to investigate microbe compositions in ginger soil to identify the difference between ginger soil with and without disease. Later, to investigate the influence of the well-known biocontrol agent B. velezensis and the fungicide Etridiazole on soil microbes and ginger productivity, we designed an experiment that collected the soil samples according to the different periods of ginger cultivation to examine the microbial community dynamics in the rhizome and bulk soil. We demonstrated that B. velezensis is beneficial to ginger reproduction. In accordance with our results, we suggest that B. velezensis may influence the plant's growth by adjusting its soil microbial composition. Etridiazole, on the other hand, may have some side effects on the ginger or beneficial bacteria in the soils that inhibit ginger reproduction. IMPORTANCE Pythium myriotylum and Ralstonia solanacearum cause soft rot disease and bacterial wilt, respectively. In this study, we used the bacterial 16S V3-V4 hypervariable region of the 16S rRNA region to investigate microbe compositions in healthy and diseased ginger soil and find out the influence of the well-known biocontrol agent B. velezensis and the fungicide Etridiazole on soil microbes and ginger productivity. These results demonstrated that B. velezensis benefits ginger reproduction and may influence the soil bacterial composition, while Etridiazole may have some side effects on the ginger or beneficial bacteria in the soils. The interactions among ginger, biocontrol agents, and fungicides need to be further investigated.

A Novel Model of Ultrasonic Fatigue Test in Pure Bending.

The very high cycle fatigue (VHCF) failure of in-service components is mainly caused by the vibration of thin-wall elements at a high frequency. In this work, a novel model of ultrasonic fatigue test was developed to test thin-wall material in bending up to VHCF with an accelerated frequency. The theoretical principle and finite element analysis were introduced for designing a sample that resonated at the frequency of 20 kHz in flexural vibration. In the advantage of the second-order flexural vibration, the gauge section of the sample was in the pure bending condition which prevented the intricate stress condition for thin-wall material as in the root of cantilever or the contact point of three points bending. Moreover, combining the constraint and the loading contact in one small section significantly reduced heating that originated from the friction at an ultrasonic frequency. Both strain gauge and deflection angle methods were applied to verify the controlling of stress amplitude. The fractography observation on Ti6Al4V samples indicated that the characterized fracture obtained from the novel model was the same as that from the conventional bending test.

High-resolution spatial and genomic characterization of coral-associated microbial aggregates in the coral Stylophora pistillata.

Bacteria commonly form aggregates in a range of coral species [termed coral-associated microbial aggregates (CAMAs)], although these structures remain poorly characterized despite extensive efforts studying the coral microbiome. Here, we comprehensively characterize CAMAs associated with Stylophora pistillata and quantify their cell abundance. Our analysis reveals that multiple Endozoicomonas phylotypes coexist inside a single CAMA. Nanoscale secondary ion mass spectrometry imaging revealed that the Endozoicomonas cells were enriched with phosphorus, with the elemental compositions of CAMAs different from coral tissues and endosymbiotic Symbiodiniaceae, highlighting a role in sequestering and cycling phosphate between coral holobiont partners. Consensus metagenome-assembled genomes of the two dominant Endozoicomonas phylotypes confirmed their metabolic potential for polyphosphate accumulation along with genomic signatures including type VI secretion systems allowing host association. Our findings provide unprecedented insights into Endozoicomonas-dominated CAMAs and the first direct physiological and genomic linked evidence of their biological role in the coral holobiont.

Microbiome Restructuring: Dominant Coral Bacterium Endozoicomonas Species Respond Differentially to Environmental Changes.

Bacteria in the coral microbiome play a crucial role in determining coral health and fitness, and the coral host often restructures its microbiome composition in response to external factors. An important but often neglected factor determining this microbiome restructuring is the ability of microbiome members to respond to changes in the environment. To address this issue, we examined how the microbiome structure of Acropora muricata corals changed over 9 months following a reciprocal transplant experiment. Using a combination of metabarcoding, genomics, and comparative genomics approaches, we found that coral colonies separated by a small distance harbored different dominant Endozoicomonas-related phylotypes belonging to two different species, including a novel species, "Candidatus Endozoicomonas penghunesis" 4G, whose chromosome-level (complete) genome was also sequenced in this study. Furthermore, the two dominant Endozoicomonas species had different potentials to scavenge reactive oxygen species, suggesting potential differences in responding to the environment. Differential capabilities of dominant members of the microbiome to respond to environmental change can (i) provide distinct advantages or disadvantages to coral hosts when subjected to changing environmental conditions and (ii) have positive or negative implications for future reefs. IMPORTANCE The coral microbiome has been known to play a crucial role in host health. In recent years, we have known that the coral microbiome changes in response to external stressors and that coral hosts structure their microbiome in a host-specific manner. However, an important internal factor, the ability of microbiome members to respond to change, has been often neglected. In this study, we combine metabarcoding, culturing, and genomics to delineate the differential ability of two dominant Endozoicomonas species, including a novel "Ca. Endozoicomonas penghunesis" 4G, to respond to change in the environment following a reciprocal transplant experiment.

Population genetics and demography of the coral-killing cyanobacteriosponge, Terpios hoshinota, in the Indo-West Pacific.

The first occurrence of the cyanobacteriosponge Terpios hoshinota was reported from coral reefs in Guam in 1973, but was only formally described in 1993. Since then, the invasive behavior of this encrusting, coral-killing sponge has been observed in many coral reefs in the West Pacific. From 2015, its occurrence has expanded westward to the Indian Ocean. Although many studies have investigated the morphology, ecology, and symbiotic cyanobacteria of this sponge, little is known of its population genetics and demography. In this study, a mitochondrial cytochrome oxidase I (COI) fragment and nuclear ribosomal internal transcribed spacer 2 (ITS2) were sequenced to reveal the genetic variation of T. hoshinota collected from 11 marine ecoregions throughout the Indo-West Pacific. Both of the statistical parsimony networks based on the COI and nuclear ITS2 were dominated by a common haplotype. Pairwise F ST and Isolation-by-distance by Mantel test of ITS2 showed moderate gene flow existed among most populations in the marine ecoregions of West Pacific, Coral Triangle, and Eastern Indian Ocean, but with a restricted gene flow between these regions and Maldives in the Central Indian Ocean. Demographic analyses of most T. hoshinota populations were consistent with the mutation-drift equilibrium, except for the Sulawesi Sea and Maldives, which showed bottlenecks following recent expansion. Our results suggest that while long-range dispersal might explain the capability of T. hoshinota to spread in the IWP, stable population demography might account for the long-term persistence of T. hoshinota outbreaks on local reefs.

A multi-step nitrifying microbial enrichment to remove ammonia and nitrite in brackish aquaculture systems.

One of the most important advancements in harnessing the biological nitrification in the field is enrichment solution of nitrifying microbial consortia. In the current study, we developed an improved multi-step enrichment to amplify a targeted microbial consortium from a sediment sample collected in tropical mangrove, Vietnam. The results showed that it took 122 culturing days with five unique continuous enrichment steps, the microbial consortium consumed total 5665 mgN L-1. Relative substrate removal rate increased rapidly from 0.114 mgN L-1 h-1 at the end of the first-step enrichment up to 3.58 mgN L-1 h-1 at the end of the fifth-step enrichment. High-throughput sequencing revealed that Nitrospirae, Proteobacteria and Bacteroidetes were the dominant taxa at the phylum level while Nitrospira, Marinobacter, Denitromonas and Nitrosomonas were the dominant taxa at the genus level in the enriched consortia. A pilot-scale experiment for shrimp cultivation of L. vannamei in 84 day-period proved the efficiency of Total ammonium nitrogen and nitrite removal in the consortium-activated treatment was much higher than the control.

In Vivo Evidence of Single 13C and 15N Isotope-Labeled Methanotrophic Nitrogen-Fixing Bacterial Cells in Rice Roots.

Methane-oxidizing bacteria (methanotrophs) play an ecological role in methane and nitrogen fluxes because they are capable of nitrogen fixation and methane oxidation, as indicated by genomic and cultivation-dependent studies. However, the chemical relationships between methanotrophy and diazotrophy and aerobic and anaerobic reactions, respectively, in methanotrophs remain unclear. No study has demonstrated the cooccurrence of both bioactivities in a single methanotroph bacterium in its natural environment. Here, we demonstrate that both bioactivities in type II methanotrophs occur at the single-cell level in the root tissues of paddy rice (Oryza sativa L. cv. Nipponbare). We first verified that difluoromethane, an inhibitor of methane monooxygenase, affected methane oxidation in rice roots. The results indicated that methane assimilation in the roots mostly occurred due to oxygen-dependent processes. Moreover, the results indicated that methane oxidation-dependent and methane oxidation-independent nitrogen fixation concurrently occurred in bulk root tissues. Subsequently, we performed fluorescence in situ hybridization and NanoSIMS analyses, which revealed that single cells of type II methanotrophs (involving six amplicon sequence variants) in paddy rice roots simultaneously and logarithmically fixed stable isotope gases 15N2 and 13CH4 during incubation periods of 0, 23, and 42 h, providing in vivo functional evidence of nitrogen fixation in methanotrophic cells. Furthermore, 15N enrichment in type II methanotrophs at 42 h varied among cells with an increase in 13C accumulation, suggesting that either the release of fixed nitrogen into root systems or methanotroph metabolic specialization is dependent on different microenvironmental niches in the root. IMPORTANCE Atmospheric methane concentrations have been continually increasing, causing methane to become a considerable environmental concern. Methanotrophy may be the key to regulating methane fluxes. Although research suggests that type II methanotrophs are involved in methane oxidation aerobically and nitrogen fixation anaerobically, direct evidence of simultaneous aerobic and anaerobic bioreactions of methanotrophs in situ is still lacking. In this study, a single-cell isotope analysis was performed to demonstrate these in vivo parallel functions of type II methanotrophs in the root tissues of paddy rice (Oryza sativa L. cv. Nipponbare). The results of this study indicated that methanotrophs might provide fixed nitrogen to root systems or depend on cells present in the spatially localized niche of the root tissue. Furthermore, our results suggested that single type II methanotrophic cells performed simultaneous methane oxidation and nitrogen fixation in vivo. Under natural conditions, however, nitrogen accumulation varied at the single-cell level.

Extra high superoxide dismutase in host tissue is associated with improving bleaching resistance in "thermal adapted" and Durusdinium trenchii-associating coral.

Global warming threatens reef-building corals with large-scale bleaching events; therefore, it is important to discover potential adaptive capabilities for increasing their temperature resistance before it is too late. This study presents two coral species (Platygyra verweyi and Isopora palifera) surviving on a reef having regular hot water influxes via a nearby nuclear power plant that exhibited completely different bleaching susceptibilities to thermal stress, even though both species shared several so-called "winner" characteristics (e.g., containing Durusdinium trenchii, thick tissue, etc.). During acute heating treatment, algal density did not decline in P. verweyi corals within three days of being directly transferred from 25 to 31 °C; however, the same treatment caused I. palifera to lose < 70% of its algal symbionts within 24 h. The most distinctive feature between the two coral species was an overwhelmingly higher constitutive superoxide dismutase (ca. 10-fold) and catalase (ca. 3-fold) in P. verweyi over I. palifera. Moreover, P. verweyi also contained significantly higher saturated and lower mono-unsaturated fatty acids, especially a long-chain saturated fatty acid (C22:0), than I. palifera, and was consistently associated with the symbiotic bacteria Endozoicomonas, which was not found in I. palifera. However, antibiotic treatment and inoculation tests did not support Endozoicomonas having a direct contribution to thermal resistance. This study highlights that, besides its association with a thermally tolerable algal symbiont, a high level of constitutive antioxidant enzymes in the coral host is crucial for coral survivorship in the more fluctuating and higher temperature environments.