ABSTRACT
Microbial residues are an important component of soil organic carbon (SOC). It is unclear how long-term thinning affects the accumulation characteristics of microbial residue carbon (C). We analyzed the differences in soil physicochemical properties, microbial communities, extracellular enzyme activities, and microbial residue C in topsoil (0-10 cm) and subsoil (20-30 cm) in Picea asperata plantation of non-thinned (control, 4950 trees·hm-2) and thinned for 14 years (1160 trees·hm-2) stands, aiming to reveal the regulatory mechanism of thinning on microbial residue C accumulation. The results showed that thinning significantly increased SOC content, total nitrogen content, available phosphorus content, the proportion of particulate organic C, soil water content, C-cycle hydrolase, and acid phosphatase activities, but significantly reduced the proportion of mineral-associated organic C. Thinning significantly affected the content of fungal and microbial residue C, and the contribution of microbial residue C to SOC, and these effects were independent of soil layer. The content of fungal and microbial residue C was 25.0% and 24.5% higher under thinning treatments. However, thinning significantly decreased the contribution of microbial residue C to SOC by 12.3%, indicating an increase in the proportion of plant-derived C in SOC. Stepwise regression analysis showed that total nitrogen and soil water content were key factors influencing fungal and micro-bial residue C accumulation. In summary, thinning promoted microbial residue C sequestration by altering soil pro-perties and changed the composition of SOC sources.
Subject(s)
Picea , Soil , Soil/chemistry , Carbon/analysis , Soil Microbiology , European Alpine Region , Minerals , China , Nitrogen/analysis , Water/analysisABSTRACT
Bronchial asthma is not considered a singular disease, but rather a collection of syndromes with multiple phenotypes and mechanisms that involve various signaling pathways. It typically emerges during the preschool years, and its etiology is intricate and diverse. In recent years, the advancement of high-throughput sequencing technology has revealed that early alterations in lung microbiota may be associated with asthma incidence and progression. Moreover, significant variations in lung microbiota have been observed among different airway inflammation profiles, known as asthma endotypes. Hence, a comprehensive understanding of the characteristics of lung microbiota in children with asthma can aid in managing disease progression and improving long-term prognosis. Additionally, such insights may spark novel approaches to diagnosing and treating childhood asthma.
Subject(s)
Child , Child, Preschool , Humans , Asthma/diagnosis , Lung , Inflammation , Phenotype , MicrobiotaABSTRACT
Objective: To investigate the changes of high density lipoprotein cholesterol (HDL-C) in sepsis patients and its early predictive value for secondary acute kidney injury (AKI) in such patients. Methods: A retrospective case series study was conducted. From June 2019 to June 2021, 232 sepsis patients who met the inclusion criteria were admitted to the Second Hospital of Hebei Medical University, including 126 males and 106 females, aged 24 to 71 years. According to whether complicating secondary AKI, the patients were divided into non-AKI group (n=158) and AKI group (n=74). Data of patients between the two groups were compared and statistically analyzed with independent sample t test or chi-square test, including the sex, age, body mass index (BMI), body temperature, heart rate, primary infection site, combined underlying diseases, acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score and sepsis-related organ failure assessment (SOFA) score at admission, and the serum levels of C-reactive protein (CRP), procalcitonin, creatinine, cystatin C, and HDL-C measured at diagnosis of sepsis. The multivariate logistic regression analysis was performed on the indicators with statistically significant differences between the two groups to screen the independent risk factors for developing secondary AKI in 232 sepsis patients, and the joint prediction model was established based on the independent risk factors. The receiver operating characteristic (ROC) curve of the independent risk factors and the joint prediction model predicting secondary AKI in 232 sepsis patients were drawn, and the area under the curve (AUC), the optimal threshold, and the sensitivity and specificity under the optimal threshold were calculated. The quality of the above-mentioned AUC was compared by Delong test, and the sensitivity and specificity under the optimal threshold were compared using chi-square test. Results: The sex, age, BMI, body temperature, heart rate, primary infection site, combined underlying diseases, and CRP level of patients between the two groups were similar (P>0.05). The procalcitonin, creatinine, cystatin C, and scores of APACHE Ⅱ and SOFA of patients in AKI group were all significantly higher than those in non-AKI group (with t values of -3.21, -16.14, -12.75, -11.13, and -12.88 respectively, P<0.01), while the HDL-C level of patients in AKI group was significantly lower than that in non-AKI group (t=6.33, P<0.01). Multivariate logistic regression analysis showed that creatinine, cystatin C, and HDL-C were the independent risk factors for secondary AKI in 232 sepsis patients (with odds ratios of 2.45, 1.68, and 2.12, respectively, 95% confidence intervals of 1.38-15.35, 1.06-3.86, and 0.86-2.56, respectively, P<0.01). The AUCs of ROC curves of creatinine, cystatin C, HDL-C, and the joint prediction model for predicting secondary AKI in 232 sepsis patients were 0.69, 0.79, 0.89, and 0.93, respectively (with 95% confidence intervals of 0.61-0.76, 0.72-0.85, 0.84-0.92, and 0.89-0.96, respectively, P values all below 0.01); the optimal threshold were 389.53 μmol/L, 1.56 mg/L, 0.63 mmol/L, and 0.48, respectively; the sensitivity under the optimal threshold were 76.6%, 81.4%, 89.7%, and 95.5%, respectively; the specificity under the optimal threshold values were 78.6%, 86.7%, 88.6%, and 96.6%, respectively. The AUC quality of cystatin C was significantly better than that of creatinine (z=2.34, P<0.05), the AUC quality and sensitivity and specificity under the optimal threshold of HDL-C were all significantly better than those of cystatin C (z=3.33, with χ2 values of 6.43 and 7.87, respectively, P<0.01) and creatinine (z=5.34, with χ2 values of 6.32 and 6.41, respectively, P<0.01); the AUC quality and sensitivity and specificity under the optimal threshold of the joint prediction model were all significantly better than those of creatinine, cystatin C, and HDL-C (with z values of 6.18, 4.50, and 2.06, respectively, χ2 values of 5.31, 7.23, 3.99, 6.56, 7.34, and 4.00, respectively, P<0.05 or P<0.01). Conclusions: HDL-C level in sepsis patients with secondary AKI is significantly lower than that in patients without secondary AKI. This is an independent risk factor for secondary AKI in sepsis patients with a diagnostic value being superior to that of creatinine and cystatin C. The combination of the aforementioned three indicators would have higher predicative valuable for secondary AKI in sepsis patients.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Acute Kidney Injury/etiology , Cholesterol, HDL , Prognosis , ROC Curve , Retrospective Studies , Sepsis/diagnosisABSTRACT
Soil microbial residues are important components of soil stable carbon (C) pools. How N-fixing tree species influence microbial residues in soil aggregates in larch plantations is still unclear. To determine the effects of N-fixing tree species on the distribution of microbial residues in different aggregates, we compared the distribution of amino sugars, biomarker of microbial residues, among aggregates in a pure larch (Larix kaempferi) plantation and a mixed plantation of larch (Larix kaempferi) and alder (Alnus sibirica) in eastern Liaoning Province. The results showed that alder did not affect the distribution of amino sugars, but significantly increased amino sugars content in soil aggregates. The total amino sugars in different soil aggregates were enriched by 130%-170% in the mixed larch plantation compared with those in pure larch plantation. The contributions of glucosamine, galactosamine and muramic acid to the increases of total amino sugars caused by alder introduction were 66.5%-66.9%, 30.0%-30.6% and 2.5%-3.2%, respectively. Alder introduction significantly accelerated the glucosamine/muramic acid ratios in >2000 µm and <250 µm aggregates, but not in 250-2000 µm aggregates. Moreover, alder introduction increased the microbial contribution to soil organic C in all aggregates, but did not influence this contribution among aggregates, indicating that the effects of alder introduction on microbial contribution to aggregates were homogeneous.
Subject(s)
Alnus/physiology , Amino Sugars/metabolism , Amino Sugars/physiology , Nitrogen Fixation , Soil Microbiology , Carbon , China , Larix , Soil , Sugars , TreesABSTRACT
Objective To analyze the epidemiological situation of human intestinal nematode infections in Nanjing City from 2006 to 2015,so as to provide the reference for formulating prevention and control measures. Methods The surveillance data of human intestinal nematode infections in Nanjing City from 2006 to 2015 were collected and analyzed statistically. Results From 2006 to 2015,98804 person-times of residents were surveyed in Nanjing City,and 465 person-times of residents were de-tected with intestinal nematode infections. The highest infection rate was in 2006(1.97%),and the lowest in 2013 and 2015 (both 0.05%). Moreover,the positive rate of human intestinal nematode infections showed a significantly declining trend in total (χ2=552.19,P<0.001). Meanwhile,the numbers of Ascaris lumbricoides,hookworm and Trichuris trichura cases were 329, 98 and 25 respectively,and the infection rates were 0.33%,0.10%and 0.03%respectively. Among them,443 cases had mild infection intensity (98.66%). There were 462 cases of single-infection (99.35%),and 3 of co-infection of two parasites (0.65%). From 2006 to 2015,92539 person-times of children under 12 years old were surveyed for Enterobius vermicularis in-fection and 352 cases were detected with E. vermicularis infection. Moreover,the positive rate showed a significantly decreasing trend in total(χ2=147.94,P<0.001). Conclusions The control effect of human intestinal nematode infections in Nanjing City is remarkable. However,the surveillance and health education in key groups still should be strengthened,and the preven-tion and control programs should be adjusted promptly to further consolidating the effectiveness of intestinal nematode disease prevention and control.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the predictors of condom-use self-efficacy in Chinese college students according to the extended parallel process model (EPPM)-based integrated model.</p><p><b>METHODS</b>A total of 3,081 college students were anonymously surveyed through self-administered questionnaires in Guangzhou and Harbin, China. A structural equation model was applied to assess the integrated model.</p><p><b>RESULTS</b>Among the participants, 1,387 (46.7%) were male, 1,586 (53.3%) were female, and the average age was 18.6 years. The final integrated model was acceptable. Apart from the direct effect (r = 0.23), perceived severity had two indirect effects on condom-use self-efficacy through the attitude to HIV education (r = 0.40) and intention to engage in premarital sex (r = -0.16), respectively. However, the perceived susceptibility mediated through the intention to engage in premarital sex (intent-to-premarital-sex) had a poor indirect impact on condom-use self-efficacy (total effect was -0.06). Furthermore, attitude toward HIV health education (r = 0.49) and intent-to-premarital-sex (r = -0.31) had a strong direct effect on condom-use self-efficacy. In addition, male students perceived higher susceptibility, stronger intent-to-premarital-sex, and lower condom-use self-efficacy than female students.</p><p><b>CONCLUSION</b>The integrated model may be used to assess the determinants of condom-use self-efficacy among Chinese college students. Future research should focus on raising the severity perception, HIV-risk-reduction motivation, and the premarital abstinence intention among college students. Furthermore, considering the gender differences observed in the present survey, single-sex HIV education is required in school-based HIV/sex intervention.</p>
Subject(s)
Adolescent , Female , Humans , Male , Young Adult , Asian People , Condoms , Health Knowledge, Attitudes, Practice , Models, Theoretical , Risk Factors , Self Efficacy , Sexual Behavior , Students , UniversitiesABSTRACT
To understand the mechanisms of soil respiration and accurately estimate its magnitude are the crucial basis of evaluating global carbon balance. However, the previously built soil respiration forecast models usually neglect the physiological processes that photosynthesis supplies substrates for rhizospheric respiration, leading to the defect in evaluating the mechanisms of soil respiration. This paper summarized the research progress on the mechanisms of photosynthetic regulation and control of soil respiration, introduced the related main research methods, and discussed the existing problems and research hotspots.
Subject(s)
Carbon Dioxide/analysis , Photosynthesis/physiology , Soil/chemistry , Cell Respiration , Environmental Monitoring , Soil Microbiology , Trees/growth & developmentABSTRACT
Objective To observe the changes of femur biomechanical properties in fluorosis rats. Methods Fifty Wistar rats of thirty-day old, weighing 90-100 g, were randomly divided according to body mass into fluorosis and control group of 25 each. Fluorosis group drank tap water containing 100 mg/L of fluoride, the control group drank tap water. The rats were observed of dental growing status and killed after feeding 6 months. Their femurs underwent tensile strength, impact, shear, bending experiments. Results The deteetable rate of dental fluorosis was significantly higher in fluorosis group[92%(23/25)] than control group[0(0/25),X2=38.97, P<0.01]. Biomeehanical data in fluorosis group(225.67±11.81,1.94±0.15,76.62±6.10,39.96.3±3.90) were lower than those of the control group(244.70±13.38,2.39±0.19,87.72±7.05,45.75±3.75) in experiments of tensile strength (MPa), impact toughness (J/mm2), shear and bending strength (MPa). The difference was statistically significant(t=3.372,5.879,3.756 and 3383, respectively, P<0.01) between the two groups. Conclusion Fluorides affected bone metabolism in rats, femur biomechanieal properties ehanged in fluorosis rats.
ABSTRACT
Spiramycin (SP) belongs to the 16-member macrolide antibiotics. It contains three components,namely SP I, SP II and SP III, which differ structurally in the acylation moieties on the C3 of the lactone. The SP I component contains a hydroxyl group at C3. SP II, and SP III are formed by further acetylation or propionylation of the C3 of SP I, by the same 3-O-acyltransferase (3-O-AT) . The study focused on simplifying spiramycin components. Theoretically, disruption/deletion of the 3-O-AT gene will reduce/stop the acylation of SP I to SP II and SP III. In this study, degenerated primers were designed according to the conserved regions of 3-O-acyltransferase, MdmB and AcyA in the medicamycin and carbomycin producers of S. mycarofaciens and S. thermotolerans, respectively, and an 878bp DNA fragment was amplified from the spiramycin-producer of S. spiramyceticus F21. Blast analysis of the 878bp DNA fragment suggested that it encoded the 3-O-acyltransferase (3-0-AT, sspA) gene for spiramycin biosynthesis. The flanking regions of this 878bp DNA fragment were then amplified by single-oligonucleotide-nested PCR, and a total of 4.3 kb DNA was obtained (3457nt among the 4.3kb fragment was sequenced, and deposited in GenBank DQ642742),covering the whole putative 3-O-acyltransferase gene, sspA. The sspA was then deleted from the S. spiramyceticus F21 genome by double cross-over homologous recombination, mediated by temperature-sensitive plasmid pKC1139. A comparison was done of the components of spiramycins produced by the sspA-deleted mutant strain with that of the parent strain by HPLC analysis, which showed that sspA-deleted mutant produced SP I (72%), SP II (18%), and SP III (9.6%), whereas parent strain produced SP I (7.8%), SP II (67%), and SP III (25%), respectively, demonstrating the role of ssp A in the acylation of SP I into SP II and SP III. The ssp A-deleted mutant strain obtained in this study may be used for the production of SP I, or may serve as a good starter for the construction of spiramycin derivatives.
Subject(s)
Acyltransferases , Genetics , Aminoglycosides , Gene Deletion , Genes, Bacterial , Genetics , Genetic Engineering , Methods , Streptomyces , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To reveal the association of 4G/5G polymorphism in the promoter region of the plasminogen activator inhibitor 1 gene (PAI1) with plasma PAI1 level in deep vein thrombosis (DVT) in Chinese Han ethnic group.</p><p><b>METHODS</b>One hundred and twenty Chinese DVT patients and 120 healthy controls were recruited. The PAI1 promoter 4G/5G polymorphism was detected using polymerase chain reaction (PCR). The antigen of tissue-type plasminogen activator (tPA) or PAI1 was quantified by a commercially available enzyme-linked immunosorbent assay (ELISA) in DVT cases and health controlsì respectively.</p><p><b>RESULTS</b>Neither in the distribution of PAI1 promoter 4G/5G polymorphism nor in the frequencies of 4G and 5G allele was there a difference between two groups. The levels of PAI1 antigen in the carriers of the 4G/4G genotype were significantly higher than those either in the 4G/5G genotype or in the 5G/5G genotype; In the 4G/5G genotype or in the 5G/5G genotype the TG levels are an independently determinant factor of PAI1 antigen levels.</p><p><b>CONCLUSION</b>There is a close relationship of the PAI1 4G/5G polymorphism to its plasma level in deep vein thrombosis in Chinese Han ethnic group, although lack of association between this genetic variation and risk of DVT suggest no major cause-effect pathogenic role of this polymorphism by itself.</p>
