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Nitrogen (N)-fixing organisms, also known as diazotrophs, play a crucial role in N-limited ecosystems by controlling the production of bioavailable N. The carbon-dominated cold-seep ecosystems are inherently N-limited, making them hotspots of N fixation. However, the knowledge of diazotrophs in cold-seep ecosystems is limited compared to other marine ecosystems. In this study, we used multi-omics to investigate the diversity and catabolism of diazotrophs in deep-sea cold-seep bottom waters. Our findings showed that the relative abundance of diazotrophs in the bacterial community reached its highest level in the cold-seep bottom waters compared to the cold-seep upper waters and non-seep bottom waters. Remarkably, more than 98% of metatranscriptomic reads aligned on diazotrophs in cold-seep bottom waters belonged to the genus Sagittula, an alphaproteobacterium. Its metagenome-assembled genome, named Seep-BW-D1, contained catalytic genes (nifHDK) for nitrogen fixation, and the nifH gene was actively transcribed in situ. Seep-BW-D1 also exhibited chemosynthetic capability to oxidize C1 compounds (methanol, formaldehyde, and formate) and thiosulfate (S2O32-). In addition, we observed abundant transcripts mapped to genes involved in the transport systems for acetate, spermidine/putrescine, and pectin oligomers, suggesting that Seep-BW-D1 can utilize organics from the intermediates synthesized by methane-oxidizing microorganisms, decaying tissues from cold-seep benthic animals, and refractory pectin derived from upper photosynthetic ecosystems. Overall, our study corroborates that carbon-dominated cold-seep bottom waters select for diazotrophs and reveals the catabolism of a novel chemosynthetic alphaproteobacterial diazotroph in cold-seep bottom waters. IMPORTANCE: Bioavailable nitrogen (N) is a crucial element for cellular growth and division, and its production is controlled by diazotrophs. Marine diazotrophs contribute to nearly half of the global fixed N and perform N fixation in various marine ecosystems. While previous studies mainly focused on diazotrophs in the sunlit ocean and oxygen minimum zones, recent research has recognized cold-seep ecosystems as overlooked N-fixing hotspots because the seeping fluids in cold-seep ecosystems introduce abundant bioavailable carbon but little bioavailable N, making most cold seeps inherently N-limited. With thousands of cold-seep ecosystems detected at continental margins worldwide in the past decades, the significant role of cold seeps in marine N biogeochemical cycling is emphasized. However, the diazotrophs in cold-seep bottom waters remain poorly understood. Through multi-omics, this study identified a novel alphaproteobacterial chemoheterotroph belonging to Sagittula as one of the most active diazotrophs residing in cold-seep bottom waters and revealed its catabolism.
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Dinitrogen (N2) fixation is a crucial source of bioavailable nitrogen in carbon-dominated cold seep systems. Previous studies have shown that diazotrophy is not necessarily dependent on sulfate-dependent anaerobic oxidation of methane for energy, and diverse catabolism can fuel the high-energy-demanding process in sediments. However, it remains unclear whether diazotroph can obtain energy by sulfur oxidation in sulfur-rich cold seep water column. Here, field investigations and in situ experiments were conducted in Haima cold seep to examine the effects of diverse sources of dissolved organic matter (DOM) on N2 fixation, specifically containing sulfur, carbon, nitrogen, and phosphorus. We found that active N2 fixation occurred in the water column above the Haima cold seep, with the Dechloromonas genus dominating the diazotroph community as revealed by nifH gene using high-throughput sequencing. In situ experiments showed an increased rate of N2 fixation (1.15- to 12.70-fold compared to that in control group) and a greater relative abundance of the Dechloromonas genus following enrichment with sulfur-containing organic matter. Furthermore, metagenomic assembly and binning revealed that Dechloromonas sp. carried genes related to N2 fixation (nifDHK) and sulfur compound oxidation (fccAB and soxABCXYZ), implying that the genus potentially serves as a multifunctional mediator for N2 fixation and sulfur cycling. Our results provide new insights regarding potential coupling mechanism associated with sulfur-driven N2 fixation in methane- and sulfide-rich environments. IMPORTANCE: N2 fixation is an important source of biologically available in carbon-dominated cold seep systems as little nitrogen is released by hydrocarbon seepage, thereby promoting biological productivity and the degradation of non-nitrogenous organic matter. Cold seeps are rich in diverse sources of dissolved organic matter (DOM) derived from the sinking of photosynthetic products in euphotic layer and the release of chemosynthesis products on the seafloor. However, it remains unclear whether N2 fixation is coupled to the metabolic processes of DOM, as determined by e.g., carbon, nitrogen, phosphorus, and sulfur content, for energy acquisition in sulfur-rich cold seeps. In this study, diazotroph community structure and its response to DOM compositions were revealed. Moreover, the metagenomics analysis suggested that Dechloromonas genus plays a dominant role in potential coupling N2 fixation and sulfur oxidation. Our study highlighted that sulfur oxidation in deep-sea cold seeps may serve as an energy source to drive N2 fixation.
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This article is aimed at discussing the combined effect of mineral admixture and servicing temperature, especially in cold environment, on the properties of magnesium phosphate repair mortar (MPM). The influence mechanism of fly ash content on the microstructure and performance of MPM were firstly investigated, and then the evolution rules in properties of fly ash modified MPM cured at - 20 °C, 0 °C, 20 °C and 40 °C were further revealed. The results show that the incorporation of fly ash has no significant effect on the setting time and fluidity of MPM. When MPM is modified with 10 wt% and 15 wt% fly ash, its mechanical properties, adhesive strength, water resistance, and volume stability are effectively improved. Fly ash reduces the crystallinity and continuity of struvite enriched in hardened MPM, and its particles are embedded among struvite and unreacted MgO. The compressive strength of MPM-10 cured for various ages increases with the elevating of curing temperature, while the flexural strength, interfacial bonding strength, strength retention and linear shrinkage exhibits the opposite laws. When cured at 0 °C and - 20 °C, MPM-10 still has good early strength, water resistance and interfacial bonding properties, which indicates that MPM-10 provides with an ability of emergency repair of cracked components served in cold environments.
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Inflammatory responses, especially chronic inflammation, are closely associated with many systemic diseases. There are many ways to treat and alleviate inflammation, but how to solve this problem at the molecular level has always been a hot topic in research. The use of nanoparticles (NPs) as anti-inflammatory agents is a potential treatment method. We synthesized new hollow cerium oxide nanomaterials (hCeO2 NPs) doped with different concentrations of Cu5.4O NPs [the molar ratio of Cu/(Ce + Cu) was 50%, 67%, and 83%, respectively], characterized their surface morphology and physicochemical properties, and screened the safe concentration of hCeO2@Cu5.4O using the CCK8 method. Macrophages were cultured, and P.g-lipopolysaccharide-stimulated was used as a model of inflammation and co-cultured with hCeO2@Cu5.4O NPs. We then observe the effect of the transcription levels of CTSB, NLRP3, caspase-1, ASC, IL-18, and IL-1ß by PCR and detect its effect on the expression level of CTSB protein by Western blot. The levels of IL-18 and IL-1ß in the cell supernatant were measured by enzyme-linked immunosorbent assay. Our results indicated that hCeO2@Cu5.4O NPs could reduce the production of reactive oxygen species and inhibit CTSB and NLRP3 to alleviate the damage caused by the inflammatory response to cells. More importantly, hCeO2@Cu5.4O NPs showed stronger anti-inflammatory effects as Cu5.4O NP doping increased. Therefore, the development of the novel nanomaterial hCeO2@Cu5.4O NPs provides a possible new approach for the treatment of inflammatory diseases.
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Antiinflamatorios , Cerio , Cobre , Inflamación , Proteína con Dominio Pirina 3 de la Familia NLR , Transducción de Señal , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Cerio/farmacología , Cerio/química , Transducción de Señal/efectos de los fármacos , Animales , Ratones , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Antiinflamatorios/farmacología , Nanopartículas , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Macrófagos/metabolismo , Inflamasomas/metabolismo , Inflamasomas/efectos de los fármacos , Células RAW 264.7 , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Wound infection caused by multidrug-resistant bacteria poses a serious threat to antibiotic therapy. Therefore, it is of vital importance to find new methods and modes for antibacterial therapy. The cerium nitrogen co-doped titanium dioxide nanoparticles (N-TiO2, 0.05Ce-N-TiO2, 0.1Ce-N-TiO2, and 0.2Ce-N-TiO2) were synthesized using the hydrothermal method in this study. Subsequently, electrospinning was employed to fabricate polylactic acid (PLA) electrospun membranes loaded with the above-mentioned nanoparticles (PLA-N, PLA-0.05, PLA-0.1, and PLA-0.2). The results indicated that cerium and nitrogen co-doping tetrabutyl titanate enhanced the visible light photocatalytic efficiency of TiO2 nanoparticles and enabled the conversion of ultraviolet light into harmless visible light. The photocatalytic reaction under visible light irradiation induced the generation of ROS, which could effectively inhibit the bacterial growth. The antibacterial assay showed that it was effective in eliminating S. aureus and E. coli and the survival rates of two types of bacteria under 30 min of irradiation were significantly below 20% in the PLA-0.2 experimental group. Moreover, the bactericidal membranes also have excellent biocompatibility performance. This bio-friendly and biodegradable membrane may be applied to skin trauma and infection in future to curb drug-resistant bacteria and provide more alternative options for antimicrobial therapy.
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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.
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Purpose: To investigate the effect of surgical resection on survival in gastrointestinal stromal tumors synchronous liver metastasis (GIST-SLM) and to develop clinically usable predictive models for overall survival (OS) and cancer-specific survival (CSS) in patients. Methods: We identified patients in the SEER database diagnosed with GISTs from 2010 to 2019. We used propensity score matching (PSM) to balance the bias between the Surgery and No surgery groups. Kaplan-Meier(K-M) analysis was used to detect differences in OS and CSS between the two groups. The nomogram to predict 1, 3, and 5-year OS and CSS were developed and evaluated. Results: After PSM, 228 patients were included in this study. There were significant differences in 1, 3, and 5-year OS and CSS between the two groups (OS: 93.5% vs. 84.4%, 73.2% vs. 55.3%, 60.9% vs. 36.9%, P=0.014; CSS: 3.5% vs.86.2%,75.3% vs.57.9%, 62.6% vs. 42.9%, P=0.02). We also found that patients who received surgery combined with targeted therapy had better OS and CSS at 1, 3, and 5 years than those who received surgery only (OS: 96.6% vs.90.9%, 74.9% vs. 56.8%, 61.7% vs. 35.5%, P=0.022; CSS: 96.6% vs. 92.1%, 77.4% vs.59.2%,63.8% vs. 42.0%, P=0.023). The area under the curve (AUC) was 0.774, 0.737, and 0.741 for 1, 3, and 5-year OS, respectively, with 0.782 and 0.742 for 1, 3, and 5-year CSS. In the model, C-index was 0.703 for OS and 0.705 for CSS and showed good consistency. Conclusion: Surgical treatment can improve the OS and CSS of patients with GIST-SLM. In addition, the combination with chemotherapy may be more favorable for the long-term survival of patients. Meanwhile, we constructed the nomograms for predicting OS and CSS at 1, 3, and 5-year, and validated them internally. Our model can contribute to clinical management and treatment strategy optimization.
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Developing low-cost and high-performance n-type polymer semiconductors is essential to accelerate the application of organic thermoelectrics (OTEs). To achieve this objective, it is critical to design strong electron-deficient building blocks with simple structure and easy synthesis, which are essential for the development of n-type polymer semiconductors. Herein, we synthesized two cyano-functionalized highly electron-deficient building blocks, namely 3,6-dibromopyrazine-2-carbonitrile (CNPz) and 3,6-Dibromopyrazine-2,5-dicarbonitrile (DCNPz), which feature simple structures and facile synthesis. CNPz and DCNPz can be obtained via only one-step reaction and three-step reactions from cheap raw materials, respectively. Based on CNPz and DCNPz, two acceptor-acceptor (A-A) polymers, P(DPP-CNPz) and P(DPP-DCNPz) are successfully developed, featuring deep-positioned lowest unoccupied molecular orbital (LUMO) energy levels, which are beneficial to n-type organic thin-film transistors (OTFTs) and OTEs performance. An optimal unipolar electron mobility of 0.85 and 1.85â cm2 V-1 s-1 is obtained for P(DPP-CNPz) and P(DPP-DCNPz), respectively. When doped with N-DMBI, P(DPP-CNPz) and P(DPP-DCNPz) show high n-type electrical conductivities/power factors of 25.3â S cm-1 /41.4â µW m-1 K-2 , and 33.9â S cm-1 /30.4â µW m-1 K-2 , respectively. Hence, the cyano-functionalized pyrazine CNPz and DCNPz represent a new class of structurally simple, low-cost and readily accessible electron-deficient building block for constructing n-type polymer semiconductors.
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Dissolved organic phosphorus (DOP) is an important nutrient for phytoplankton growth in oligotrophic oceans. However, little is known about the impact of DOP on phytoplankton growth in eutrophic waters. In the present study, we conducted field monitoring as well as in situ and laboratory experiments in the Pearl River estuary (PRE). Field observations showed an increase in the nitrogen-to-phosphorus ratio and DOP in recent years in the PRE. The phytoplankton community was dominated by nanophytoplankton Cyclotella in the upper and middle estuary, with high concentrations of DOP and light limitation during the ebb stage of the spring to neap tide in summer. The relative abundance of Cyclotella in natural waters was higher after enrichment with estuarine water with a background of 0.40-0.46 µM DOP, even when dissolved inorganic phosphorus was sufficient (0.55-0.76 µM). In addition, the relative abundance of Cyclotella in natural waters was higher after enrichment with phosphoesters. Laboratory culture results also confirmed that phosphoesters can enhance the growth rate of Cyclotella cryptica. Our study highlights that Cyclotella can become the dominant species in estuaries with increased levels of phosphoesters and low and fluctuating light adaptability and under the joint effect of dynamic processes such as upwelling and tides. Our results provide new insights into the role of Cyclotella in biogeochemical cycles affected by DOP utilization and potential applications in relieving the hypoxia of tropical eutrophic estuaries.IMPORTANCEThis study provides evidence that Cyclotella can become the dominant species in estuaries with increased levels of phosphoesters and low and fluctuating light adaptability and under the joint effect of dynamic processes such as upwelling and tides. Our study provides new insights into the role of Cyclotella in biogeochemical cycles affected by dissolved organic phosphorus utilization, especially affected by anthropogenic inputs and climate change. Potential applications include relieving the hypoxia of tropical eutrophic estuaries.
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Diatomeas , Materia Orgánica Disuelta , Humanos , Estuarios , Ríos , Fitoplancton , Fósforo/análisis , Hipoxia , Monitoreo del AmbienteRESUMEN
Noctiluca scintillans (red) is a widely distributed heterotrophic dinoflagellate and a prominent red tide forming species. This study investigated the effects of Noctiluca blooms on marine microbial diversity and functionality using multi-omics approaches. Our findings revealed significant differences in the community composition of Noctiluca-associated bacteria compared to those associated with autotrophic plankton and free-living bacteria in the surrounding seawater. The dominant bacterial groups within the Noctiluca-associated community shifted at various bloom stages, which could be attributed to changes in prey composition of Noctiluca. During the non-bloom stage, Burkholderiaceae, Carnobacteriaceae, and Pseudomonadaceae dominated the community, while Vibrionaceae became dominant during the bloom stage, and Saprospiraceae, Crocinitomicaceae, and Pirellulaceae thrived during the post-bloom stage. Compared to the non-bloom stage, Noctiluca-associated bacterial community at the bloom stage exhibited significant down-regulation of genes related to complex carbohydrate metabolism, while up-regulation of genes related to glucose transportation and utilization. Furthermore, we identified Vibrio anguillarum, a potential pathogenic bacterium to marine fish, as a major component of the Vibrionaceae family during the bloom stage. The occurrence of V. anguillarum associated with Noctiluca blooms may be attributed to the increased availability of its preferred carbon sources and its high capabilities in glucose transportation, motility and chemotaxis. Moreover, the presence of Vibrio infection genes (hap, hlyA, rtxA) encoding vibriolysin, hemolysin, and RTX (Repeats-in-toxin) toxin in the V. anguillarum genome, with the hap gene showing high expression levels during Noctiluca blooms, indicates an elevated risk of infection. This study underscores the unique composition of the bacterial community associated with red tide forming heterotrophic dinoflagellates and suggests that Noctiluca cells may serve as reservoirs and vectors for pathogenic bacteria, potentially posing a threat to fish-farming and the health of other marine organisms.
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Dinoflagelados , Dinoflagelados/fisiología , Floraciones de Algas Nocivas/fisiología , Bacterias , Carbohidratos , GlucosaRESUMEN
In 2017 summer, we observed widespread bottom hypoxia at the lower estuary of the Pearl River estuary (PRE). Our previous study noticed that AOA and bacteria were highly abundant and clustered within the hypoxia zone. Moreover, nitrification and respiration rates were also evidently higher in these hypoxic waters. These observations prompt us to investigate whether these two oxygen-consuming microorganisms have symbiotic relationships and whether specific groups consistently coexist and form ecological-meaningful associations. In this study, we use network analysis to investigate the presence and active communities (DNA-RNA) based on bacterial and AOA communities sequencing (inferred from the 16S rRNA and amoA gene, respectively) to gain more insight into ecological-meaningful associations. We observed a highly diverse and active bacterial community in the hypoxia zone. The RNA networks were more modulized than the corresponding DNA networks, indicating that the active communities were better parsed into functional microbial assemblages. The network topology revealed that Gammaproteobacteria, Bacteroidetes (Flavobacteriales), Alphaproteobacteria (Rhodobacterales and Rhodospirillales), Marinimicrobia, Cyanobacteria (Synechococcales), and AOA sublineages were module hubs and connectors, indicating that they were the keystone taxa of the microbial communities. The hub-subnetwork further showed robust co-occurrence between Gammaproteobacteria, Bacteroidetes (Flavobacteriales), Alphaproteobacteria (Rhodobacterales and Rhodospirillales), Marinimicrobia with AOA sublineages, and Nitrospinae (presumably NOB) reflecting the formation of Degradation-Nitrification (sequential oxidation of Organic matter degradation to ammonia, then nitrate) microbial assemblage in the hypoxia zone. The subnetworks revealed AOA ecotype-specific modularization and niche partitioning of different AOA sublineages. Interestingly, the recurring co-occurrence of nitrifiers assemblage in the RNA subnetworks (SCM1-like-II (AOA) and Nitrospinae OTUs (NOB) suggests an active interaction via nitrite exchange. The Degradation-Nitrification microbial assemblage may contribute substantially to the oxygen consumption in the hypoxia formation in PRE. Our results provide new insight into the functional microbial assemblages, which is worth further investigation on their ecological implication in estuarine waters.
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Archaea , Nitrificación , Humanos , Estuarios , ARN Ribosómico 16S/genética , Bacterias/metabolismo , Oxidación-Reducción , Amoníaco/metabolismo , ADN , Hipoxia , Filogenia , Microbiología del SueloRESUMEN
Cathepsins are a type of lysosomal globulin hydrolase and are crucial for many physiological processes, including the resorption of bone matrix, innate immunity, apoptosis, proliferation, metastasis, autophagy, and angiogenesis. Findings regarding their functions in human physiological processes and disorders have drawn extensive attention. In this review, we will focus on the relationship between cathepsins and oral diseases. We highlight the structural and functional properties of cathepsins related to oral diseases, as well as the regulatory mechanisms in tissue and cells and their therapeutic uses. Elucidating the associated mechanism between cathepsins and oral diseases is thought to be a promising strategy for the treatment of oral diseases and may be a starting point for further studies at the molecular level.
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Catepsinas , Enfermedades de la Boca , Humanos , Enfermedades de la Boca/terapia , Apoptosis/fisiología , Inmunidad Innata , Matriz ÓseaRESUMEN
Understanding microbial community structure and the underlying control mechanisms are fundamental purposes of aquatic ecology. However, little is known about the seasonality and how trophic conditions regulate plankton community in subtropical reservoirs. In this study, we study the prokaryotic and picoeukaryotic communities and their interactions during wet and dry seasons in two subtropical reservoirs: one at oligotrophic state and another at mesotrophic state. Distinct microbial community compositions (prokaryotes and picoeukaryotes) and seasonal variation pattern were detected in the oligotrophic and mesotrophic reservoirs. The interactions between prokaryotic and picoeukaryotic communities were more prevalent in the oligotrophic reservoir, suggesting enhanced top-down control of small eukaryotic grazers on the prokaryotic communities. On the other hand, the microbial community in the mesotrophic reservoir was more influenced by physico-chemical parameters and showed a stronger seasonal variation, which may be the result of distinct nutrient levels in wet and dry seasons, indicating the importance of bottom-up control. Our study contributes to new understandings of the environmental and biological processes that shape the structure and dynamics of the planktonic microbial communities in reservoirs of different trophic states.
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Microbiota , Plancton , Eucariontes , Estaciones del AñoRESUMEN
Understanding the biogeographical and biodiversity patterns of bacterial communities is essential in unraveling their responses to future environmental changes. However, the relationships between marine planktonic bacterial biodiversity and seawater chlorophyll a are largely understudied. Here, we used high-throughput sequencing to study the biodiversity patterns of marine planktonic bacteria across a broad chlorophyll a gradient spanning from the South China Sea across the Gulf of Bengal to the northern Arabian Sea. We found that the biogeographical patterns of marine planktonic bacteria complied with the scenario of homogeneous selection, with chlorophyll a concentration being the key environmental selecting variable of bacteria taxa. The relative abundance of Prochlorococcus, the SAR11 clade, the SAR116 clade, and the SAR86 clade significantly decreased in habitats with high chlorophyll a concentrations (>0.5 µg/L). Free-living bacteria (FLB) and particle-associated bacteria (PAB) displayed contrasting alpha diversity and chlorophyll a relationships with a positive linear correlation for FLB but a negative correlation for PAB. We further found that PAB had a narrower niche breadth of chlorophyll a than did FLB, with far fewer bacterial taxa being favored at higher chlorophyll a concentrations. Higher chlorophyll a concentrations were linked to the enhanced stochastic drift and reduced beta diversity of PAB but to the weakened homogeneous selection, enhanced dispersal limitation, and increased beta diversity of FLB. Taken together, our findings might broaden our knowledge about the biogeography of marine planktonic bacteria and advance the understanding of bacterial roles in predicting ecosystem functioning under future environmental changes that are derived from eutrophication. IMPORTANCE One of the long-standing interests of biogeography is to explore diversity patterns and uncover their underlying mechanisms. Despite intensive studies on the responses of eukaryotic communities to chlorophyll a concentrations, we know little about how changes in seawater chlorophyll a concentrations affect free-living bacteria (FLB) and particle-associated bacteria (PAB) diversity patterns in natural systems. Our biogeography study demonstrated that marine FLB and PAB displayed contrasting diversity and chlorophyll a relationships and exhibited completely different assembly mechanisms. Our findings broaden our knowledge about the biogeographical and biodiversity patterns of marine planktonic bacteria in nature systems and suggest that PAB and FLB should be considered independently in predicting marine ecosystem functioning under future frequent eutrophication.
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Ecosistema , Plancton , Clorofila A , Plancton/genética , Biodiversidad , Bacterias/genética , Agua de Mar/microbiología , ChinaRESUMEN
The emergence of multidrug-resistant bacteria has been deemed a global crisis that affects humans worldwide. Novel anti-infection strategies are desperately needed because of the limitations of conventional antibiotics. However, the increasing gap between clinical demand and antimicrobial treatment innovation, as well as the membrane permeability obstacle especially in gram-negative bacteria fearfully restrict the reformation of antibacterial strategy. Metal-organic frameworks (MOFs) have the advantages of adjustable apertures, high drug-loading rates, tailorable structures, and superior biocompatibilities, enabling their utilization as drug delivery carriers in biotherapy applications. Additionally, the metal elements in MOFs are usually bactericidal. This article provides a review of the state-of-The-art design, the underlying antibacterial mechanisms and antibacterial applications of MOF- and MOF-based drug-loading materials. In addition, the existing problems and future perspectives of MOF- and MOF-based drug-loading materials are also discussed.
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Infecciones Bacterianas , Estructuras Metalorgánicas , Humanos , Infecciones Bacterianas/tratamiento farmacológico , Antibacterianos/farmacología , Permeabilidad de la Membrana Celular , Portadores de Fármacos , Sistemas de Liberación de Medicamentos , MetalesRESUMEN
Cluster 5 Synechococcus is one of the most important primary producers on earth. However, ecotypes of this genus exhibit complex geographical distributions, and the genetic basis of niche partitioning is still not fully understood. Here, we report distinct distributions of subcluster 5.1 (SC5.1) and subcluster 5.2 (SC5.2) Synechococcus in estuarine waters, and we reveal that salinity is the main factor determining their distribution. Clade III (belonging to SC5.1) and CB4 (belonging to SC5.2) are dominant clades in the study region, with different ecological distributions. We further conducted physiological, genomic, and transcriptomic studies of Synechococcus strains YX04-3 and HK05, which are affiliated with clade III and CB4, respectively. Laboratory tests showed that HK05 could grow at low salinity (13 ppt), whereas the growth of YX04-3 was suppressed when salinity decreased to 13 ppt. Genomic and transcriptomic analysis suggested that euryhaline clade CB4 is capable of dealing with a sudden drop of salinity by releasing compatible solutes through mechanosensitive channels that are coded by the mscL gene, decreasing biosynthesis of organic osmolytes, and increasing expression of heat shock proteins and high light-inducible proteins to protect photosystem. Furthermore, CB4 strain HK05 exhibited a higher growth rate when growing at low salinity than at high salinity. This is likely achieved by reducing its biosynthesis of organic osmolyte activity and increasing its photosynthetic activity at low salinity, which allowed it to enhance the assimilation of inorganic carbon and nitrogen. Together, these results provide new insights regarding the ecological distribution of SC5.2 and SC5.1 ecotypes and their underlying molecular mechanisms. IMPORTANCE Synechococcus is a group of unicellular Cyanobacteria that are widely distributed in global aquatic ecosystems. Salinity is a factor that affects the distribution of microorganisms in estuarine and coastal environments. In this study, we studied the distribution pattern of Synechococcus community along the salinity gradient in a subtropical estuary. By using omic methods, we unveiled genetic traits that determine the niche partitioning of euryhaline and strictly marine Synechococcus. We also explored the strategies employed by euryhaline Synechococcus to cope with a sudden drop of salinity, and revealed possible mechanisms for the higher growth rate of euryhaline Synechococcus in low salinity conditions. This study provides new insight into the genetic basis of niche partitioning of Synechococcus clades.
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Synechococcus , Synechococcus/genética , Agua de Mar/microbiología , Ecosistema , Transcriptoma/genética , Tolerancia a la Sal/genética , GenómicaRESUMEN
The design and preparation of advanced nanocatalysts for the sensitive electrochemical detection of H2O2 is of great significance. Herein, a facile Pt@Co/MoN sensing platform was fabricated by depositing Pt nanoparticles onto Co/MoN nanoarrays using atomic layer deposition (ALD) technology. Benefitting from the unique nanostructure and the strong interaction between Pt and the nitride support, the prepared Pt@Co/MoN exhibited excellent performance in the electrochemical detection of H2O2. This work provides an interesting strategy to fabricate low-Pt electrocatalysts on a nanoarray support for future applications in electroanalysis.
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Periodontitis is one of the most prevalent diseases in oral cavity, which could not merely lead to the destruction of supporting or surrounding tooth structures but also affect the whole-body health such as the digestive and nervous systems. Epidemiological investigations suggested that in some developed countries, more than 45% or even 50% population were suffering from periodontitis. However, the prevalence increases with age remarkably and it is investigated that a high prevalence (>50%) is affecting the elderly who is over 65 years old. There is an increasing interest in the direct and indirect relationships between periodontitis and hyperuricemia. Currently, hyperuricemia has become the second major metabolic disease in modern society and the prevalence of hyperuricemia among adult males and females was 21.7% and 14.4% respectively. As an inflammatory disease associated with various systemic diseases, periodontitis may have certain connections with hyperuricemia. Partial existing research announced that hyperuricemia could act as an inhibitory factor for periodontitis, while other scholars presented that a high uric acid (UA) level was more likely to aggravate inflammatory immune response and lead to more serious tissue destruction. This article provides a detailed and comprehensive overview of the relationship underlying hyperuricemia and periodontitis in the molecular mechanisms. Given the impact of hyperuricemia, this review could provide insight into its comorbidities.
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Hiperuricemia , Periodontitis , Adulto , Anciano , Femenino , Masculino , Humanos , Hiperuricemia/epidemiología , Periodontitis/epidemiologíaRESUMEN
Background: Clinicians frequently face difficulties when trying to fix bone abnormalities. Gelatin-Alginate (GA) is frequently employed as a carrier because it is non-toxic, biodegradable, and has a three-dimensional network structure. Meanwhile, cerium oxide nanoparticles (nCeO2) demonstrated high antioxidant enzyme simulation activity. Therefore, in order to develop a porous hydrogel scaffold for the application of bone tissue engineering, an appropriate-type GA-nCeO2 hydrogel scaffold was developed and evaluated. Methods: GA-nCeO2 hydrogel scaffold was prepared by the lyophilized method and characterized. The surface morphology and cell adhesion of the scaffold were observed by the scanning electron microscope. CCK8 and live-dead staining methods were used to evaluate its biological safety and cell proliferation. Then the osteogenic differentiation in early and late stages was discussed. The expression of osteogenic genes was also detected by RT-PCR. Finally, a bone defect model was made in SD rats, and bone formation in vivo was detected. Results: The results showed that GA-nCeO2 hydrogel scaffold exhibited a typical three-dimensional porous structure with a mean pore ratio of 70.61 ± 1.94%. The GA-nCeO2 hydrogel was successfully endowed with simulated enzyme activity including superoxide dismutase (SOD) and catalase (CAT) after the addition of nCeO2. Osteoblasts demonstrated superior cell proliferation and adhesion on composite scaffolds, and both mineralization test and gene expression demonstrated the strong osteogenic potential of GA-nCeO2 hydrogel. The outcomes of hematoxylin and eosin (H&E) staining and Masson trichrome staining in the femoral defect model of SD rats further supported the scaffold's favorable biocompatibility and bone-promoting capacity. Conclusion: Due to its favorable safety, degradability, and bone formation property, GA-nCeO2 hydrogel was anticipated to be used as a potential bone defect healing material.
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Nanoestructuras , Osteogénesis , Ratas , Animales , Osteogénesis/genética , Ingeniería de Tejidos/métodos , Hidrogeles/química , Gelatina/química , Andamios del Tejido/química , Alginatos/química , Ratas Sprague-Dawley , Diferenciación Celular , Regeneración ÓseaRESUMEN
During a series of blooms of Noctiluca scintillans and Mesodinium rubrum, we applied high-throughput sequencing of the 16S rRNA gene to investigate the population dynamics of free-living (FL) and particle-attached (PA) bacteria in an attempt to evaluate the influence of protozoan bloom-induced disturbances on the structuring of these two communities. Our findings revealed that the FL and PA bacterial community compositions (BCCs) displayed distinct profiles during sequential blooms, and the PA flora responded more dynamically to these pulse perturbations. The dominant bacterial groups (e.g., Flavobacteriaceae, Rhodobacteraceae, Vibrionaceae, and SAR11 subclade I) in these two communities displayed different levels of connectivity with the bloom-causative species and environmental factors. In addition, more FL bacterial groups were associated with M. rubrum, while more PA bacterial groups were related to N. scintillans. Potential endocytic bacteria of N. scintillans, particularly Vibrionaceae and Rickettsiaceae, opportunistically thrived at the peak of the bloom, suggesting that they could be important players influencing the dynamics and biogeochemical cycling of the blooms. Overall, disparities in the substrate preferences and thermal niches of various bacterial taxa as well as the short duration of the blooms (1 to 3 days) contributed to the diverse responses of the FL and PA bacterial communities to these protozoan blooms. Our research provides insight into the responses of FL and PA bacterial communities to blooms caused by protozoa like N. scintillans and M. rubrum and highlights the ecological significance of certain keystone bacterial groups during this kind of cosmopolitan protozoan bloom. IMPORTANCE Shifts in the bacterioplankton community composition during phytoplankton blooms have been studied extensively; however, investigations on protozoan blooms are rare. This study first evaluated the impact of perturbations caused by sequential protozoan blooms of the heterotrophic dinoflagellate Noctiluca scintillans and the mixotrophic ciliate Mesodinium rubrum on the structuring of these two bacterial communities. Our findings shed light on the responses of these two bacterial communities to such cosmopolitan protozoan blooms and highlight the possible ecological significance of certain keystone bacterial groups during these blooms. This research prepares the way for more focused studies that will help in understanding the roles that bacteria play during protozoan blooms and their impact on environmental health.