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1.
J Colloid Interface Sci ; 675: 915-925, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-39002241

ABSTRACT

The optimization of the adsorption of oxygen-containing intermediates on platinum (Pt) sites of Pt-based electrocatalysts is crucial for the oxygen reduction reaction process. Currently, a large amount of researches mainly focus on modifying the bulk structure of the electrocatalysts, however, the vital role of solvent effect on the phase interfaces is often overlooked. Here, we successfully developed an electrocatalyst in which the ordered PtCo alloy anchors on the cobalt (Co) single-atoms/clusters decorated support (Co1,nNC) and its surface is further optimized using hydrophobic ionic liquid (IL). Experimental studies and theoretical calculations indicate that compressive stress on Pt lattice contributed by intrinsic structure and the local hydrophobicity caused by IL on the surface can suppress the stabilization of *OH on Pt. This synergistic effect affords outstanding catalytic performance, exhibiting a half-wave potential (E1/2) of 0.916 V vs. RHE and a mass activity (MA) of 1350.3 mA mgPt-1 in 0.1 mol/L perchloric acid (0.1 M HClO4) electrolyte, much better than the commercial Pt/C (0.849 V vs. RHE and 145.5 mA mgPt-1 for E1/2 and MA, respectively). Moreover, the E1/2 of IL-PtCo/Co1,nNC only lost 5 mV after 10,000 cyclic voltammetry (CV) cycles due to a strong and synergistic contact of the intermetallic PtCo alloy with the Co1,nNC support and IL. This research provides an effective method for designing efficient electrocatalysts by combining intrinsic structure and surface modification.

2.
Medicine (Baltimore) ; 103(27): e38721, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38968499

ABSTRACT

BACKGROUND: Raiomics is an emerging auxiliary diagnostic tool, but there are still differences in whether it can be applied to predict early recurrence of hepatocellular carcinoma (HCC). The purpose of this meta-analysis was to systematically evaluate the predictive power of radiomics in the early recurrence (ER) of HCC. METHODS: Comprehensive studies on the application of radiomics to predict ER in HCC patients after hepatectomy or curative ablation were systematically screened in Embase, PubMed, and Web of Science. RESULTS: Ten studies which is involving a total of 1929 patients were reviewed. The overall estimates of radiomic models for sensitivity and specificity in predicting the ER of HCC were 0.79 (95% confidence interval [CI]: 0.68-0.87) and 0.83 (95% CI: 0.73-0.90), respectively. The area under the summary receiver operating characteristic curve (SROC) was 0.88 (95% CI: 0.85-0.91). CONCLUSIONS: The imaging method is a reliable method for diagnosing HCC. Radiomics, which is based on medical imaging, has excellent power in predicting the ER of HCC. With the help of radiomics, we can predict the recurrence of HCC after surgery more effectively and provide a useful reference for clinical practice.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Neoplasm Recurrence, Local , Carcinoma, Hepatocellular/diagnostic imaging , Carcinoma, Hepatocellular/surgery , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/surgery , Liver Neoplasms/pathology , Humans , Neoplasm Recurrence, Local/diagnostic imaging , Hepatectomy/methods , Predictive Value of Tests , Sensitivity and Specificity , Radiomics
3.
Pathogens ; 13(7)2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39057819

ABSTRACT

Fusarium graminearum is the primary causative agent of Fusarium head blight (FHB), a devastating disease affecting cereals globally. The high-mobility group (HMG) of non-histone proteins constitutes vital architectural elements within chromatin, playing diverse roles in various biological processes in eukaryotic cells. Nonetheless, the specific functions of HMG proteins in F. graminearum have yet to be elucidated. Here, we identified 10 HMG proteins in F. graminearum and extensively characterized the biological roles of one HMGB protein, FgNhp6. We constructed the FgNhp6 deletion mutant and its complementary strains. With these strains, we confirmed the nuclear localization of FgNhp6 and discovered that the absence of FgNhp6 led to reduced radial growth accompanied by severe pigmentation defects, a significant reduction in conidial production, and a failure to produce perithecia. The ∆FgNhp6 mutant exhibited a markedly reduced pathogenicity on wheat coleoptiles and spikes, coupled with a significant increase in deoxynivalenol production. An RNA sequencing (RNA-seq) analysis indicated that FgNhp6 deletion influenced a wide array of metabolic pathways, particularly affecting several secondary metabolic pathways, such as sterol biosynthesis and aurofusarin biosynthesis. The findings of this study highlight the essential role of FgNhp6 in the regulation of the asexual and sexual reproduction, deoxynivalenol (DON) production, and pathogenicity of F. graminearum.

4.
Arab J Gastroenterol ; 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39048387

ABSTRACT

BACKGROUND AND STUDY AIMS: Mucosal healing (MH) is a crucial indicator of therapeutic effectiveness and prognosis in Crohn's disease (CD). Rapid achievement and long-term maintenance of MH can alleviate the financial and psychological burden on patients. This study aimed to investigate the factors associated with MH in CD patients and enhance clinicians' understanding. PATIENTS AND METHODS: Patients diagnosed with CD between January 2010 and December 2019 at our hospital were included and divided into two groups based on the attainment of MH during the follow-up period. Demographic data, symptoms, disease classification, laboratory examination results, and treatments were collected and compared between the two groups. Factors with a P-value <0.2 were subjected to multivariate logistic regression analysis to identify the related factors of MH. RESULTS: Multivariate logistic regression analysis of CD patients revealed that educational level [odds ratio (OR) = 8.167, 95 % confidence interval (CI) 1.440-46.303, P = 0.018] and biological therapy (OR = 15.291, 95 % CI 1.404-166.543, P = 0.025) were associated with MH. CONCLUSION: Educational level and biological therapy are factors related to MH in CD patients. These findings suggest that the use of biological therapy and patients' better understanding of the disease contribute to achieving MH.

5.
Adv Sci (Weinh) ; : e2404545, 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39041942

ABSTRACT

Microbial tryptophan (Trp) metabolites acting as aryl hydrocarbon receptor (AhR) ligands are shown to effectively improve metabolic diseases via regulating microbial community. However, the underlying mechanisms by which Trp metabolites ameliorate bone loss via gut-bone crosstalk are largely unknown. In this study, supplementation with Trp metabolites, indole acetic acid (IAA), and indole-3-propionic acid (IPA), markedly ameliorate bone loss by repairing intestinal barrier integrity in ovariectomy (OVX)-induced postmenopausal osteoporosis mice in an AhR-dependent manner. Mechanistically, intestinal AhR activation by Trp metabolites, especially IAA, effectively repairs intestinal barrier function by stimulating Wnt/ß-catenin signaling pathway. Consequently, enhanced M2 macrophage by supplementation with IAA and IPA secrete large amount of IL-10 that expands from intestinal lamina propria to bone marrow, thereby simultaneously promoting osteoblastogenesis and inhibiting osteoclastogenesis in vivo and in vitro. Interestingly, supplementation with Trp metabolites exhibit negligible ameliorative effects on both gut homeostasis and bone loss of OVX mice with intestinal AhR knockout (VillinCreAhrfl/fl). These findings suggest that microbial Trp metabolites may be potential therapeutic candidates against osteoporosis via regulating AhR-mediated gut-bone axis.

6.
Acad Radiol ; 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39025700

ABSTRACT

RATIONALE AND OBJECTIVES: To develop and validate a clinical-radiomics model of dynamic contrast-enhanced MRI (DCE-MRI) for the preoperative discrimination of Vessels encapsulating tumor clusters (VETC)- microvascular invasion (MVI) and prognosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: 219 HCC patients from Institution 1 were split into internal training and validation groups, with 101 patients from Institution 2 assigned to external validation. Histologically confirmed VETC-MVI pattern categorizing HCC into VM-HCC+ (VETC+/MVI+, VETC-/MVI+, VETC+/MVI-) and VM-HCC- (VETC-/MVI-). The regions of intratumor and peritumor were segmented manually in the arterial, portal-venous and delayed phase (AP, PP, and DP, respectively) of DCE-MRI. Six radiomics models (intratumor and peritumor in AP, PP, and DP of DCE-MRI) and one clinical model were developed for assessing VM-HCC. Establishing intra-tumoral and peri-tumoral models through combining intratumor and peritumor features. The best-performing radiomics model and the clinical model were then integrated to create a Combined model. RESULTS: In institution 1, pathological VM-HCC+ were confirmed in 88 patients (training set: 61, validation set: 27). In internal testing, the Combined model had an AUC of 0.85 (95% CI: 0.76-0.93), which reached an AUC of 0.75 (95% CI: 0.66-0.85) in external validation. The model's predictions were associated with early recurrence and progression-free survival in HCC patients. CONCLUSIONS: The clinical-radiomics model offers a non-invasive approach to discern VM-HCC and predict HCC patients' prognosis preoperatively, which could offer clinicians valuable insights during the decision-making phase.

7.
mSphere ; 9(7): e0005924, 2024 Jul 30.
Article in English | MEDLINE | ID: mdl-38980075

ABSTRACT

Osseointegrated dental implants replace missing teeth and create an artificial surface for biofilms of complex microbial communities to grow. These biofilms on implants and dental surfaces can trigger infection and inflammation in the surrounding tissue. This study investigated the microbial characteristics of peri-implant mucositis (PM) and explored the correlation between microbial ecological imbalance, community function, and disease severity by comparing the submucosal microflora from PM with those of healthy inter-subject implants and intra-subject gingivitis (G) within a group of 32 individuals. We analyzed submucosal plaques from PM, healthy implant (HI), and G sites using metagenome shotgun sequencing. The bacterial diversity of HIs was higher than that of PM, according to the Simpson index. Beta diversity revealed differences in taxonomic and functional compositions across the groups. Linear discriminant analysis of the effect size identified 15 genera and 37 species as biomarkers that distinguished PM from HIs. Pathways involving cell motility and protein processing in the endoplasmic reticulum were upregulated in PM, while pathways related to the metabolism of cofactors and vitamins were downregulated. Microbial dysbiosis correlated positively with the severity of clinical inflammation measured by the sulcus bleeding index (SBI) in PM. Prevotella and protein processing in the endoplasmic reticulum also correlated positively with the SBI. Our study revealed PM's microbiological and functional traits and suggested the importance of certain functions in disease severity.IMPORTANCEPeri-implant mucositis is an early stage in the progression of peri-implantitis. The high prevalence of it has been a threat to the widespread use of implant prosthodontics. The link between the submucosal microbiome and peri-implant mucositis was demonstrated previously. Nevertheless, the taxonomic and functional composition of the peri-implant mucositis microbiome remains controversial. In this study, we comprehensively characterize the microbial signature of peri-implant mucositis and for the first time, we investigate the correlations between microbial dysbiosis, functional potential, and disease severity. With the help of metagenomic sequencing, we find the positive correlations between microbial dysbiosis, genus Prevotella, pathway of protein processing in the endoplasmic reticulum, and more severe mucosal bleeding in the peri-implant mucositis. Our studies offer insight into the pathogenesis of peri-implant mucositis by providing information on the relationships between community function and disease severity.


Subject(s)
Bacteria , Dental Implants , Dysbiosis , Microbiota , Humans , Male , Middle Aged , Female , Bacteria/classification , Bacteria/isolation & purification , Bacteria/genetics , Dental Implants/microbiology , Dental Implants/adverse effects , Adult , Dysbiosis/microbiology , Severity of Illness Index , Aged , Gingivitis/microbiology , Peri-Implantitis/microbiology , Mucositis/microbiology , Stomatitis/microbiology , Stomatitis/etiology , Metagenome , Biofilms/growth & development
8.
Front Neurosci ; 18: 1378844, 2024.
Article in English | MEDLINE | ID: mdl-39071180

ABSTRACT

Acute large hemispheric infarction (ALHI) is an overwhelming emergency with a great challenge of gastrointestinal dysfunction clinically. Here, we initially proposed delayed bowel movements as the clinical phenotype of strike to gut-brain axis (GBA) in ALHI patients by epidemiological analysis of 499 acute ischemic stroke (AIS) patients. 1H NMR-based metabolomics revealed that AIS markedly altered plasma global metabolic profiling of patients compared with healthy controls. Risk factors of strike on GBA were the National Institutes of Health Stroke Scale (NIHSS) score ≥ 5 and stroke onset time ≤ 24 h. As a result, first defecating time after admission to the hospital ≥2 days could be considered as a potential risk factor for strike on GBA. Subsequently, the ALHI Bama miniature (BM) pig model with acute symptomatic seizure was successfully established by ligation of the left ascending pharyngeal artery combined with local air injection. Clinical phenotypes of brain necrosis such as hemiplegia were examined with brain diffusion-weighted imaging (DWI) and pathological diagnosis. In addition to global brain injury and inflammation, we also found that ALHI induced marked alterations of intestinal barrier integrity, the gut microbial community, and microbiota-derived metabolites including serotonin and neurotransmitters in both plasma and multiple brain tissues of BM pigs. These findings revealed that microbiota-gut-brain axis highly contributed to the occurrence and development of ALHI.

9.
Anal Chem ; 2024 Jul 30.
Article in English | MEDLINE | ID: mdl-39080839

ABSTRACT

The construction of coassembled peptide nanoprobes based on structural adaptation provides an effective template for stable monitoring of the molecular events in physiological and pathological processes. This also greatly expands their applications in biomedicine, such as multimodal combined diagnosis and treatment. However, the insufficient understanding of the physicochemical properties and structural features of different molecules still makes it difficult to construct the coassembled probes with mutually reinforcing functions, leading to unpredictable effects. Here, we showed how to utilize the π-π stacking network on ß-sheets formed by PD-L1-targeting peptides to capture small molecules with ferroptosis functions, thus, coassembling them into a visual probe with synergistic effects. Compared with individual components, the coassembled strategy could significantly improve the stability of the nanoprobe, inducing stronger ferroptosis effects and immune checkpoint blocking effects, and track and reflect the process. This study provides new insights into the design of multicomponent collaborative coassembly systems with biological effects.

10.
Sci China Life Sci ; 2024 Jul 24.
Article in English | MEDLINE | ID: mdl-39060614

ABSTRACT

The oxidative pentose phosphate (OPP) pathway provides metabolic intermediates for the shikimate pathway and directs carbon flow to the biosynthesis of aromatic amino acids (AAAs), which serve as basic protein building blocks and precursors of numerous metabolites essential for plant growth. However, genetic evidence linking the two pathways is largely unclear. In this study, we identified 6-phosphogluconate dehydrogenase 2 (PGD2), the rate-limiting enzyme of the cytosolic OPP pathway, through suppressor screening of arogenate dehydrogenase 2 (adh2) in Arabidopsis. Our data indicated that a single amino acid substitution at position 63 (glutamic acid to lysine) of PGD2 enhanced its enzyme activity by facilitating the dissociation of products from the active site of PGD2, thus increasing the accumulation of AAAs and partially restoring the defective phenotype of adh2. Phylogenetic analysis indicated that the point mutation occurred in a well-conserved amino acid residue. Plants with different amino acids at this conserved site of PGDs confer diverse catalytic activities, thus exhibiting distinct AAAs producing capability. These findings uncover the genetic link between the OPP pathway and AAAs biosynthesis through PGD2. The gain-of-function point mutation of PGD2 identified here could be considered as a potential engineering target to alter the metabolic flux for the production of AAAs and downstream compounds.

11.
Front Microbiol ; 15: 1387870, 2024.
Article in English | MEDLINE | ID: mdl-38903799

ABSTRACT

Lily bulbs, which have both nutrient storage and reproductive functions, are a representative group of plants for studying the maintenance and transfer of plant-associated microbiomes. In this study, a comparison of the microbial composition of bulbs and their regenerated seedlings cultured under aseptic conditions, as well as subcultured seedlings that succeeded five times, was examined by amplicon sequencing. A total of 62 bacterial taxa and 56 fungal taxa were found to be transferred to the 5th generation in seedlings, which are the core microbiome of lily. After the regeneration of seedlings from bulbs, there was a significant increase in the number of detectable microbial species, and after 1, 3, and 5 successive generations, there was a decrease in the number of detectable species. Interestingly, some "new" microorganisms appeared in each generation of samples; for instance, 167 and 168 bacterial operational taxonomic units (OTUs) in the 3rd and 5th generations of seedlings that were not detected in either bulbs or seedlings of the previous two generations. These results suggest that bulbs can maintain a high diversity of microorganisms, including some with ultra-low abundance, and have a high transfer capacity to tuck shoots through continuous subculture. The diversity and maintenance of the microbiome can provide the necessary microbial reservoir support for regenerating seedlings. This habit of maintaining low abundance and high diversity may be biologically and ecologically critical for maintaining microbiome stability and function due to the sequestration nature of the plant.

12.
Geriatr Nurs ; 58: 446-458, 2024 Jun 22.
Article in English | MEDLINE | ID: mdl-38909541

ABSTRACT

OBJECTIVE: self-care is critically important for the long-term management of heart failure (HF) patients, with caregivers playing an important role in promoting self-care. However, adherence to self-care is typically low among HF patients worldwide. METHODS: In-depth qualitative interviews were conducted with individuals diagnosed with HF. To structure the interview guide and underpin the analysis, two established behavioral science frameworks, the Behavior Change Wheel (BCW) and the Theoretical Domains Framework (TDF), were used in this study. RESULTS: A total of 32 participants were included (n = 16 patients, n = 16 caregivers), with themes involving: barriers included: "Self-care with Limited Capability," "Insufficient External Support," "Lack of Motivation for Self-Care." Facilitators included: "Striving to Adapt to Disease Demands," "Adequate External Support," "Positive Health Behaviors and Experiences." CONCLUSIONS: Providing positive support to heart failure patients and their caregivers, along with cultivating intrinsic motivation for behavioral change, can enhance self-care ability.

13.
J Opt Soc Am A Opt Image Sci Vis ; 41(6): 988-999, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38856406

ABSTRACT

We propose a model-driven projected algebraic reconstruction technique (PART)-network (PART-Net) that leverages the advantages of the traditional model-based method and the neural network to improve the imaging quality of diffuse fluorescence tomography. In this algorithm, nonnegative prior information is incorporated into the ART iteration process to better guide the optimization process, and thereby improve imaging quality. On this basis, PART in conjunction with a residual convolutional neural network is further proposed to obtain high-fidelity image reconstruction. The numerical simulation results demonstrate that the PART-Net algorithm effectively improves noise robustness and reconstruction accuracy by at least 1-2 times and exhibits superiority in spatial resolution and quantification, especially for a small-sized target (r=2m m), compared with the traditional ART algorithm. Furthermore, the phantom and in vivo experiments verify the effectiveness of the PART-Net, suggesting strong generalization capability and a great potential for practical applications.

14.
Chem Sci ; 15(22): 8355-8362, 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38846401

ABSTRACT

Biomarkers are present in various metabolism processes, demanding precise and meticulous analysis at the single-molecule level for accurate clinical diagnosis. Given the need for high sensitivity, biological nanopore have been applied for single biomarker sensing. However, the detection of low-volume biomarkers poses challenges due to their low concentrations in dilute buffer solutions, as well as difficulty in parallel detection. Here, a droplet nanopore technique is developed for low-volume and high-throughput single biomarker detection at the sub-microliter scale, which shows a 2000-fold volume reduction compared to conventional setups. To prove the concept, this nanopore sensing platform not only enables multichannel recording but also significantly lowers the detection limit for various types of biomarkers such as angiotensin II, to 42 pg. This advancement enables direct biomarker detection at the picogram level. Such a leap forward in detection capability positions this nanopore sensing platform as a promising candidate for point-of-care testing of biomarker at single-molecule level, while substantially minimizing the need for sample dilution.

15.
Anal Chem ; 96(27): 11092-11102, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38924493

ABSTRACT

Peptide self-assemblies could leverage their specificity, stability, biocompatibility, and electrochemical activity to create functionalized interfaces for molecular sensing and detection. However, the dynamics within these interfaces are complex, with competing forces, including those maintaining peptide structures, recognizing analytes, and facilitating signal transmission. Such competition could lead to nonspecific interference, compromising the detection sensitivity and accuracy. In this study, a series of peptides with precise structures and controllable electron transfer capabilities were designed. Through examining their stacking patterns, the interplay between the peptides' hierarchical structures, their ability to recognize targets, and their conductivity were clarified. Among these, the EP5 peptide assembly was identified for its ability to form controllable electronic tunnels facilitated by π-stacking induced ß-sheets. EP5 could enhance the long-range conductivity, minimize nonspecific interference, and exhibit targeted recognition capabilities. Based on EP5, an electrochemical sensing interface toward the disease marker PD-L1 (programmed cell death ligand 1) was developed, suitable for both whole blood assay and in vivo companion diagnosis. It opens a new avenue for crafting electrochemical detection interfaces with specificity, sensitivity, and compatibility.


Subject(s)
Electrochemical Techniques , Electrochemical Techniques/methods , Humans , Protein Conformation, beta-Strand , Peptides/chemistry , B7-H1 Antigen/analysis , B7-H1 Antigen/blood , Electrons , Animals
16.
Biomed Opt Express ; 15(6): 3654-3669, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38867798

ABSTRACT

Time-domain (TD) spatial frequency domain (SFD) diffuse optical tomography (DOT) potentially enables laminar tomography of both the absorption and scattering coefficients. Its full time-resolved-data scheme is expected to enhance performances of the image reconstruction but poses heavy computational costs and also susceptible signal-to-noise ratio (SNR) limits, as compared to the featured-data one. We herein propose a computationally-efficient linear scheme of TD-SFD-DOT, where an analytical solution to the TD phasor diffusion equation for semi-infinite geometry is derived and used to formulate the Jacobian matrices with regard to overlap time-gating data of the time-resolved measurement for improved SNR and reduced redundancy. For better contrasting the absorption and scattering and widely adapted to practically-available resources, we develop an algebraic-reconstruction-technique-based two-step linear inversion procedure with support of a balanced memory-speed strategy and multi-core parallel computation. Both simulations and phantom experiments are performed to validate the effectiveness of the proposed TD-SFD-DOT method and show an achieved tomographic reconstruction at a relative depth resolution of ∼4 mm.

17.
Nat Plants ; 10(6): 954-970, 2024 06.
Article in English | MEDLINE | ID: mdl-38831046

ABSTRACT

Hybrid rice has achieved high grain yield and greatly contributes to food security, but the manual-labour-intensive hybrid seed production process limits fully mechanized hybrid rice breeding. For next-generation hybrid seed production, the use of small-grain male sterile lines to mechanically separate small hybrid seeds from mixed harvest is promising. However, it is difficult to find ideal grain-size genes for breeding ideal small-grain male sterile lines without penalties in the number of hybrid seeds and hybrid rice yield. Here we report that the use of small-grain alleles of the ideal grain-size gene GSE3 in male sterile lines enables fully mechanized hybrid seed production and dramatically increases hybrid seed number in three-line and two-line hybrid rice systems. The GSE3 gene encodes a histone acetyltransferase that binds histones and influences histone acetylation levels. GSE3 is recruited by the transcription factor GS2 to the promoters of their co-regulated grain-size genes and influences the histone acetylation status of their co-regulated genes. Field trials demonstrate that genome editing of GSE3 can be used to immediately improve current elite male sterile lines of hybrid rice for fully mechanized hybrid rice breeding, providing a new perspective for mechanized hybrid breeding in other crops.


Subject(s)
Histones , Oryza , Plant Breeding , Oryza/genetics , Oryza/metabolism , Histones/metabolism , Histones/genetics , Acetylation , Plant Breeding/methods , Seeds/genetics , Seeds/metabolism , Edible Grain/genetics , Histone Acetyltransferases/metabolism , Histone Acetyltransferases/genetics , Plant Proteins/genetics , Plant Proteins/metabolism , Gene Expression Regulation, Plant , Hybridization, Genetic
18.
Harmful Algae ; 135: 102633, 2024 May.
Article in English | MEDLINE | ID: mdl-38830715

ABSTRACT

Nitrogen-fixing cyanobacteria not only cause severe blooms but also play an important role in the nitrogen input processes of lakes. The production of extracellular polymeric substances (EPS) and the ability to fix nitrogen from the atmosphere provide nitrogen-fixing cyanobacteria with a competitive advantage over other organisms. Temperature and nitrogen availability are key environmental factors in regulating the growth of cyanobacteria. In this study, Dolichospermum (formerly known as Anabaena) was cultivated at three different temperatures (10 °C, 20 °C, and 30 °C) to examine the impact of temperature and nitrogen availability on nitrogen fixation capacity and the release of EPS. Initially, confocal laser scanning microscopy (CLSM) and the quantification of heterocysts at different temperatures revealed that lower temperatures (10 °C) hindered the differentiation of heterocysts under nitrogen-deprived conditions. Additionally, while heterocysts inhibited the photosynthetic activity of Dolichospermum, the secretion of EPS was notably affected by nitrogen limitation, particularly at 30 °C. Finally, real-time quantitative polymerase chain reaction (qPCR) was used to measure the expression of nitrogen-utilizing genes (ntcA and nifH) and EPS synthesis-related genes (wzb and wzc). The results indicated that under nitrogen-deprived conditions, the expression of each gene was upregulated, and there was a significant correlation between the upregulation of nitrogen-utilizing and EPS synthesis genes (P < 0.05). Our findings suggested that Dolichospermum responded to temperature variation by affecting the formation of heterocysts, impacting its potential nitrogen fixation capacity. Furthermore, the quantity of EPS released was more influenced by nitrogen availability than temperature. This research enhances our comprehension of interconnections between nitrogen deprivation and EPS production under the different temperatures.


Subject(s)
Extracellular Polymeric Substance Matrix , Nitrogen Fixation , Nitrogen , Temperature , Nitrogen/metabolism , Extracellular Polymeric Substance Matrix/metabolism , Anabaena/metabolism , Anabaena/physiology , Anabaena/genetics
19.
Genes (Basel) ; 15(6)2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38927687

ABSTRACT

Crucian carp (Carassius auratus) is widely distributed in the world and has become an economically freshwater fish. The population in Lake Dali Nur can tolerate the extreme alkaline environment with alkalinity over 50 mmol/L (pH 9.6), thus providing a special model for exploring alkali-tolerant molecular markers in an extremely alkaline environment. In this study, we constructed a high-density and high-resolution linkage map with 16,224 SNP markers based on genotyping-by-sequencing (GBS) consisting of 152 progenies and conducted QTL studies for alkali-tolerant traits. The total length of the linkage map was 3918.893 cM, with an average distance of 0.241 cM. Two QTLs for the ammonia-N-tolerant trait were detected on LG27 and LG45. A QTL for the urea-N-tolerant trait was detected on LG27. Interestingly, mapping the two QTLs on LG27 revealed that the mapped genes were both located in the intron of CDC42. GO functional annotation and KEGG enrichment analysis results indicated that the biological functions might be involved in the cell cycle, cellular senescence, MAPK, and Ras signaling pathways. These findings suggest that CDC42 may play an important role in the process of dealing with extremely alkaline environments.


Subject(s)
Chromosome Mapping , Polymorphism, Single Nucleotide , Quantitative Trait Loci , Animals , Chromosome Mapping/methods , Goldfish/genetics , Carps/genetics , Alkalies
20.
Environ Sci Technol ; 58(25): 11140-11151, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38867458

ABSTRACT

Microplastic records from lake cores can reconstruct the plastic pollution history. However, the associations between anthropogenic activities and microplastic accumulation are not well understood. Huguangyan Maar Lake (HML) is a deep-enclosed lake without inlets and outlets, where the sedimentary environment is ideal for preserving a stable and historical microplastic record. Microplastic (size: 10-500 µm) characteristics in the HML core were identified using the Laser Direct Infrared Imaging system. The earliest detectable microplastics appeared unit in 1955 (1.1 items g-1). The microplastic abundance ranged from n.d. to 615.2 items g-1 in 1955-2019 with an average of 134.9 items g-1. The abundance declined slightly during the 1970s and then increased rapidly after China's Reform and Opening Up in 1978. Sixteen polymer types were detectable, with polyethylene and polypropylene dominating, accounting for 23.5 and 23.3% of the total abundance, and the size at 10-100 µm accounted for 80%. Socioeconomic factors dominated the microplastic accumulation based on the random forest modeling, and the contributions of GDP per capita, plastic-related industry yield, and total crop yield were, respectively, 13.9, 35.1, and 9.3% between 1955-2019. The total crop yield contribution further increased by 1.7% after 1978. Coarse sediment particles increased with soil erosion exacerbated microplastics discharging into the sediment.


Subject(s)
Environmental Monitoring , Lakes , Microplastics , China , Microplastics/analysis , Water Pollutants, Chemical/analysis , Plastics , Geologic Sediments/chemistry
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