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1.
J Environ Manage ; 325(Pt A): 116597, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36308785

RESUMO

Currently, the influence of elevated atmospheric CO2 concentration (eCO2) on ammonia oxidation to nitrite, the rate-limiting step of nitrification in paddy soil, is poorly known. Previous studies that simulate the effect of eCO2 on nitrification are primarily based on an abrupt increase of atmospheric CO2 concentration. However, paddy ecosystems are experiencing a gradual increase of CO2 concentration. To better understand how the nitrification potential, abundance and communities of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) respond to eCO2 in paddy ecosystems, a field experiment was conducted using the following two treatments: a gradual increase of CO2 (EC, increase of 40 ppm per year until 200 ppm above ambient) and ambient CO2 (CK). The results demonstrated that the EC treatment significantly (P < 0.05) stimulated the soil potential nitrification rate (PNR) at the jointing and milky stages, which increased by 127.83% and 27.35%, respectively, compared with CK. Furthermore, the EC treatment significantly (P < 0.05) stimulated the AOA and AOB abundance by 56.60% and 133.84%, respectively, at the jointing stage. Correlation analysis showed that the PNR correlated well with the abundance of AOB (R2 = 0.7389, P < 0.001). In addition, the EC treatment significantly (P < 0.05) altered the community structure of AOB, while it had little effect on that of AOA. A significant difference in the proportion of Nitrosospira was observed between CO2 treatments. In conclusion, the gradual increase of CO2 positively influenced the PNR and abundance of ammonia oxidizers, and AOB could be more important than AOA in nitrification under eCO2.


Assuntos
Betaproteobacteria , Nitrificação , Amônia , Dióxido de Carbono , Microbiologia do Solo , Ecossistema , Archaea , Solo/química , Oxirredução , Filogenia
2.
Microb Ecol ; 85(2): 441-453, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35098330

RESUMO

Candidatus Methanoperedens-like archaea, which can use multiple electron acceptors (nitrate, iron, manganese, and sulfate) for anaerobic methane oxidation, could play an important role in reducing methane emissions from freshwater wetlands. Currently, very little is known about the distribution and community composition of Methanoperedens-like archaea in freshwater wetlands, particularly based on their alpha subunit of methyl-coenzyme M reductase (mcrA) genes. Here, the community composition, diversity, and abundance of Methanoperedens-like archaea were investigated in a freshwater wetland through high-throughput sequencing and quantitative PCR on their mcrA genes. A large number of Methanoperedens-like mcrA gene sequences (119,250) were recovered, and a total of 31 operational taxonomic units (OTUs) were generated based on 95% sequence similarity cut-off. The majority of Methanoperedens-like sequences can be grouped into three distinct clusters that were closely associated with the known Methanoperedens species which can couple anaerobic methane oxidation to nitrate or iron reduction. The community composition of Methanoperedens-like archaea differed significantly among different sampling sites, and their mcrA gene abundance was 1.49 × 106 ~ 4.62 × 106 copies g-1 dry soil in the examined wetland. In addition, the community composition of Methanoperedens-like archaea was significantly affected by the soil water content, and the archaeal abundance was significantly positively correlated with the water content. Our results suggest that the mcrA gene is a good biomarker for detection and quantification of Methanoperedens-like archaea, and provide new insights into the distribution and environmental regulation of these archaea in freshwater wetlands.


Assuntos
Archaea , Áreas Alagadas , Archaea/genética , Nitratos , Solo , Filogenia , Oxirredução , Água Doce , Metano , Água , Ferro , Anaerobiose
3.
Diabetes Metab Syndr Obes ; 15: 2417-2425, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35971523

RESUMO

Purpose: The purpose of our study was to analyze the characteristics of OGTT and the correlation between the insulin to C-peptide molar ratio (ICPR), HOMA-IR and insulin antibodies (IAs) in T2DM patients. Patients and Methods: A total of 77 T2DM patients were included and divided into the IA+ group (25 patients) and IA- group (52 patients). The values of serum glucose, insulin, and C-peptide testing during 2-h OGTT were summarized comparatively, and ROC was made to analyze the predictive value of ICPR for IAs. Results: At each time point of OGTT, there was no significant difference in serum glucose and C-peptide changes (p>0.05). Serum insulin levels in positive patients were elevated or not at different time points of the OGTT but ICPR was significantly different (P<0.05) in the two groups. Spearman correlation coefficient analysis showed that the presence of insulin antibodies was correlated with ICPR, but not with HOMA-IR, and ICPR-2h had a better prediction capacity (AUC=0.735, the optimal cutoff-point=0.11, Se=0.760, Sp=0.635). Conclusion: T2DM patients with IAs showed no difference in serum glucose and serum C-peptide changes, but elevated or not insulin levels on the OGTTs, compared with negative patients. ICPR-2h can be a preliminary diagnostic index to timely predict IAs in T2DM patients.

4.
Fish Shellfish Immunol Rep ; 2: 100027, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36420481

RESUMO

Previously a pattern recognition receptor (PRR) from kuruma shrimp was found able to recognize bacterial glycans by the C-type lectin domain (CTLD) and to interact with Jak/Stat receptor Domeless by the interleukin-like coiled coil (cc) region. In the current study, its homolog, namely Pc-ccCL, was found important in the antiviral response in red swamp crayfish Procambarus clarkii. This PRR plays a role by inhibiting white spot syndrome virus (WSSV) infection in a Jak/Stat dependent manner. The CTLD can bind the viral envelope protein VP28, while the cc region determines the dependence on Jak/Stat pathway. Two anti-lipopolysaccharides factors were identified as the downstream antiviral peptides. This study provides new insights into the antiviral signaling in invertebrates. Furthermore, the mechanism that a PRR recognizes virus and directly activates Jak/Stat pathway and antiviral-effector expression represents a simple but fast antiviral strategy in crustaceans.

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