Postfire Phosphorus Enrichment Mitigates Nitrogen Loss in Boreal Forests.

Net nitrogen mineralization (Nmin) and nitrification regulate soil N availability and loss after severe wildfires in boreal forests experiencing slow vegetation recovery. Yet, how microorganisms respond to postfire phosphorus (P) enrichment to alter soil N transformations remains unclear in N-limited boreal forests. Here, we investigated postfire N-P interactions using an intensive regional-scale sampling of 17 boreal forests in the Greater Khingan Mountains (Inner Mongolia-China), a laboratory P-addition incubation, and a continental-scale meta-analysis. We found that postfire soils had an increased risk of N loss by accelerated Nmin and nitrification along with low plant N demand, especially during the early vegetation recovery period. The postfire N/P imbalance created by P enrichment acts as a "N retention" strategy by inhibiting Nmin but not nitrification in boreal forests. This strategy is attributed to enhanced microbial N-use efficiency and N immobilization. Importantly, our meta-analysis found that there was a greater risk of N loss in boreal forest soils after fires than in other climatic zones, which was consistent with our results from the 17 soils in the Greater Khingan Mountains. These findings demonstrate that postfire N-P interactions play an essential role in mitigating N limitation and maintaining nutrient balance in boreal forests.

Highly-sensitive temperature sensor based on photopolymerized-waveguide embedded Mach-Zehnder interferometer.

Biology, medicine, and chemistry all rely heavily on highly sensitive optical fiber temperature sensors. To the best of our knowledge, this research introduces a unique design framework for high-performance fiber temperature sensors that helps eliminate the all-fiber interferometers' sensitivity bottleneck. A section of photopolymerized waveguide is embedded in a typical Mach-Zehnder interferomenter framework with multimode fiber-single mode fiber-multimode fiber (MSM) structure. The thermal-optical coefficient (TOC) of the photopolymerized waveguide core, which is created via the fiber-end lithography technique, differs dramatically from that of the resin cladding. Due to the considerable TOC difference, the phase difference between the interfering beams significantly increases as the temperature changes. The fundamental variables affecting temperature sensitivity are conceptually explored and experimentally verified. The suggested device achieves a typical temperature sensitivity of 1.15 nm/ ∘C in the range of 30-100 ∘C, which is about 10 times as high as that of the all-fiber MSM sensors. The suggested designing framework offers a fresh thought for creating high-performing fiber optic temperature sensors.

Dietary supplementation with probiotics increases growth performance, improves the intestinal mucosal barrier and activates the Wnt/ß-catenin pathway activity in chicks.

BACKGROUND: Probiotics comprise effective feed additives that can replace antibiotics in animal livestock production. However, mono-strain probiotics appear less effective because of their instability. Therefore, the present study aimed to investigate dietary supplementation with compound probiotics (CPP) on growth performance, diarrhea rate and intestinal mucosal barrier, as well as the possible molecular mechanism, in chicks. In total, 360 1-day-old chicks of the Hy-Line Brown Chicks were randomly divided into the control group (CON, basal diet), chlortetracycline group (500 mg kg-1 CTC) and compound probiotics group (1000 mg kg-1 CPP, consisting of Bacillus subtilis, Bacillus licheniformis, Enterococcus faecium and yeast). The experiment period was 56 days. RESULTS: The results showed that, in comparison with the CON group, CPP significantly increased the average daily feed intake and average daily gain of chicks and reduced diarrhea (P < 0.05). The probiotic group exhibited increased immune organ (i.e. spleen and thymus) mass and increased levels of serum immunoglobulin (Ig)A, IgM and IgG (P < 0.05) compared to the CTC group. In addition, the jejunal mass and morphology were improved in the probiotic group (P < 0.05). Moreover, CPP reinforced jejunal barrier function, as indicated by increased transepithelial electrical resistance, protein expression of occludin and claudin-1, and diamine oxidase levels in the jejunum (P < 0.05). Likewise, enhanced fluorescence signals of proliferating cell nuclear antigen-labeled mitotic cells and villin-labeled absorptive cells in the jejunum (P < 0.05) suggested that CPP promoted intestinal stem cells activity. Mechanistically, the Wnt/ß-catenin signaling pathway, including ß-catenin, TCF4, c-Myc, cyclin D1 and Lgr5, was amplified in the jejunum by CPP addition (P < 0.05). CONCLUSION: The present study demonstrated that dietary supplementation with CPP reinforced the jejunal epithelial integrity by activating Wnt/ß-catenin signaling and enhanced immune function in chicks. © 2023 Society of Chemical Industry.

How do soil microbes exert impact on soil respiration and its temperature sensitivity?

Understanding how soil microorganisms influence the direction and magnitude of soil carbon feedback to global warming is vital to predict future climate change. Although microbial activities are major contributors to soil respiration (RS ) and its temperature sensitivity (Q10 ), the mechanisms underpinning microbial influence on RS and Q10 remain unclear. Coupling variation partitioning analysis (VPA), correlation analysis and multiple stepwise linear regression analysis, we illustrate that bacteria mainly affect RS and its temperature sensitivity (Q10 ) by shifting bacterial community composition (denoted by principal coordinates analysis). We also found that soil water content (SWC) and available nutrient (AN) were the factor key to changing bacterial community composition (P < 0.05). Co-occurrence network demonstrated that Mod 0 ecological cluster composed of copiotrophic taxa groups was significantly associated with RS and Q10 (P < 0.01, R > 0.5), including Proteobacteria, Actinobacteria, and Bacteroidetes. Illuminating the mechanisms underpinning the influence of soil microbes on RS and Q10 values is fundamental to understanding mechanistic soil-climate carbon cycles.

Expression of the non-neuronal cholinergic system components in Malpighian tubules of Mythimna separata and evidence for non-neuronal acetylcholine synthesis.

The non-neuronal cholinergic system, widely distributed in nature, is an ancient system that has not been well studied in insects. This study aims to investigate the key components of the cholinergic system and to identify the non-neuronal acetylcholine (ACh)-producing cells and the acting sites of ACh in the Malpighian tubules (MTs) of Mythimna separata. We found that non-neuronal ACh in MTs is synthesized by carnitine acetyltransferase (CarAT), rather than choline acetyltransferase (ChAT), as confirmed by using enzyme inhibitors and high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). Fluorescence in situ hybridization revealed the presence of CarAT mRNA within MTs, specifically localized in the principal cells. Immunohistochemistry showed strong staining for A-mAChR, a muscarinic acetylcholine receptor, in the principal cells. Pharmacological analysis further demonstrated that ACh acts through A-mAChR in the principal cells to increase the intracellular Ca2+ concentration. These findings provide compelling evidence for the existence of a non-neuronal cholinergic system in the MTs of M. separata, and the principal cells play a crucial role in ACh synthesis via CarAT.

Viral lysing can alleviate microbial nutrient limitations and accumulate recalcitrant dissolved organic matter components in soil.

Viruses are critical for regulating microbial communities and biogeochemical processes affecting carbon/nutrient cycling. However, the role of soil phages in controlling microbial physiological traits and intrinsic dissolved organic matter (DOM) properties remains largely unknown. Herein, microcosm experiments with different soil phage concentrates (including no-added phages, inactive phages, and three dilutions of active phages) at two temperatures (15 °C and 25 °C) were conducted to disclose the nutrient and DOM dynamics associated with viral lysing. Results demonstrated three different phases of viral impacts on CO2 emission at both temperatures, and phages played a role in maintaining Q10 within bounds. At both temperatures, microbial nutrient limitations (especially P limitation) were alleviated by viral lysing as determined by extracellular enzyme activity (decreased Vangle with active phages). Additionally, the re-utilization of lysate-derived DOM by surviving microbes stimulated an increase of microbial metabolic efficiency and recalcitrant DOM components (e.g., SUV254, SUV260 and HIX). This research provides direct experimental evidence that the "viral shuttle" exists in soils, whereby soil phages increase recalcitrant DOM components. Our findings advance the understanding of viral controls on soil biogeochemical processes, and provide a new perspective for assessing whether soil phages provide a net "carbon sink" vs. "carbon source" in soils.

DL-methionine and DL-methionyl-DL-methionine increase intestinal development and activate Wnt/ß-catenin signaling activity in domestic pigeons (Columba livia).

This experiment was undertaken to investigate the effects of parental dietary DL-methionine (DL-Met) and DL-methionyl-DL-methionine (DL-Met-Met) supplementation on the intestinal development of young squabs. A total of 108 pairs of breeding pigeons and 432 one-day-old squabs were randomly divided into 3 groups: the control group (CON) was fed a basal diet (CP = 15%) and the experimental groups were fed a basal diet supplemented with 0.3% DL-Met or DL-Met-Met. Each pair of breeding pigeons nourished 4 young squabs, and 8 squabs from each treatment were randomly sampled at the end of the experiment. The results indicated that DL-Met and DL-Met-Met supplementation improved the intestinal morphology and structure in the squabs, as reflected by the increased relative intestinal weight of each small intestinal segment, villus height, and villus to crypt ratio. In addition, DL-Met and DL-Met-Met supplementation significantly increased the protein expression of cell proliferation markers (Ki67 and PCNA) and tight junction proteins (ZO-1 and Claudin-1) in the jejunum and strengthened the fluorescence signal intensity of Ki67, PCNA and Villin. Moreover, the expression of Wnt/ß-catenin signaling pathway-related proteins (Frizzled 7 [FZD7], p-GSK-3ß, Active ß-catenin, ß-catenin, TCF4, c-Myc, and Cyclin D1), and intestinal peptide transporter 1 (PepT1) in the jejunum was considerably higher in the treatment group than in the CON group (P < 0.05), with the DL-Met-Met group having the highest expression. Consistently, the molecular docking results predicted the possibility that DL-Met or DL-Met-Met binds to the membrane receptor FZD7, which mediates Wnt/ß-catenin signaling. Collectively, the improvement of the intestinal development in squabs after parental dietary 0.3% DL-Met and DL-Met-Met supplementation could be through activation of Wnt/ß-catenin signaling pathway, and DL-Met-Met is superior to DL-Met. Our findings may provide basic data for further optimizing the feeding formula of breeding pigeons and improving the growth and development of squabs.

Characteristics of microbial community composition and its relationship with carbon, nitrogen and sulfur in sediments.

Microorganisms play an important role in the biogeochemical cycles of lacustrine sediments. However, little is known about their vertical responses to sedimentary depths and their contributions to important element cycles such as carbon, nitrogen and sulfur. Here, we investigated the community features of sedimental prokaryotes along with vertical profiles (i.e., sedimental depths of 0-230 cm) in the Dongting watershed. In the entire profile, the bacterial diversity wavelike decreased with increasing sediment depths, whereas archaeal diversity increased monotonically in the deep layer (100-230 cm). Bacteria were more sensitive to sedimental depths than archaea (B: P < 0.001, R = 0.534; A: P < 0.001, R = 0.327). The relative abundance of the primary phylum of bacteria (e.g. Proteobacteria) and archaea (e.g. Thaumarchaeota) changed significantly with sediment layers (P < 0.05). The vertical distribution of prokaryotes in sediments was related to the changes in sediment properties (P < 0.05, e.g., the content of nutrients, pH, texture, etc.). The co-occurrence network analysis further indicated that the superficial (0-40 cm) and deep (100-230 cm) networks contained more tightly connected node groups (more modules number), while the tighter connections (shorter APL) and more complex networks (higher avgK) were seen in sub-deep (40-100 cm) sediments. Based on the FAPROTAX database, we found that the predicted prokaryotic microbial functional groups involved in the N cycle had the highest abundance (87.47%), followed by the C cycle (9.48%) and the S cycle (2.39%). In addition, these groups were enriched in the superficial and deep layers. Taken together, these results reveal a new perspective on the vertical spatial variation in microorganisms at the fine-scale of the lake sediments. Distinct microbiome response patterns may have important implications for carbon, nitrogen and sulfur cycling along with the sediment profile in Dongting lake ecosystems.

Chronological records of sediment organic carbon at an entrance of Dongting Lake: Response to historical meteorological events.

Lake sediments are the products of soil erosion and are strongly influenced by climate variability, particularly extreme meteorological events. Sediment organic carbon (SOC) can reflect environmental changes that affect sediment transport. However, the response of SOC chronological records to major meteorological events is relatively unknown. This study explored the chronological regularity of SOC and verified its variations using major historical meteorological events. Based on three sediment profiles with a depth of 230 cm at the Yuan River entrance to the West Dongting Lake (Hanshou entrance), the SOC chronology was reconstructed by employing the sedimentation rates calculated by 137Cs and 210Pb. The sedimentary environment then was interpreted via comparisons and quantitative analysis. The grain distribution and the S-shaped distribution of SOC reflected the general deposition regularity of organic carbon in lake sediments, which gradually stabilized with depth. The average sedimentation rates based on 137Cs and 210Pb were 1.310 and 1.319 cm a-1, respectively. Accordingly, SOC records covered the past 76 years via dating (0-100 cm), during which the SOC content first increased and subsequently stabilized. By comparing the data with the occurrence of 11 major historical meteorological events, we found that SOC generally increased after these events. Moreover, the frequent occurrence of meteorological events stabilized the SOC content. Severe floods had a greater impact on SOC content than severe droughts, causing SOC to change by up to 20.24% and 8.77%, respectively. Our findings suggest that major historical meteorological events can verify SOC chronological records, thereby highlighting their significant impacts on organic carbon variations in sediments.

Bacteria are more sensitive than fungi to moisture in eroded soil by natural grass vegetation restoration on the Loess Plateau.

Community composition and respiration rates of bacterial and fungal communities from grass-covered eroded soils of the Loess Plateau responded differently to constant and increasing soil moisture (SM) regimes. The soils were incubated with SM contents of 5%, 30%, and 45% and with wetting processes in the SM ranges from 5% to 30% (5-30%), from 5% to 30% to 45% (5-30-45%) and from 30% to 45% (30-45%); high-throughput sequencing and co-occurrence network analyses were applied to investigate the different responses of the bacterial and fungal communities to changed SM. Our results showed that bacteria were more sensitive than fungi to changes in SM. The dominant bacterial communities converted from Actinobacterial to Proteobacteria and Acidobacteria in 5-30-45% wetting procedure. Firmicutes preferred wet condition and exhibited slow resilience. However, no difference was observed for the Chloroflexi communities across any sample. The obvious difference in fungal composition was found between the wetting process of 5-30-45% and constant 45% SM. During the 5-30-45% procedure, the respiration rate was higher than that at 30-45% procedure after incubation for 24 days. The respiration rate in 5-30% procedure was lower than that of 5-30-45% process after incubation for 16-27 days. The larger effects on bacterial response than on fungi were verified in network analysis. Multiple stepwise regression analysis showed that 84.40% of the variation in bacterial richness and diversity as well as fungal diversity can be explained by changes in soil respiration rate in response to wetting procedure. Understanding the response of difference between bacterial and fungal community composition, phylum-levels networks and respiration rate to changes in SM is essential for the management of plant-soil-water relationship in the ecosystem after natural vegetation restoration on the Loess Plateau.

[The analysis of fundus fluorescein angiography, indocyanine green angiography and hemodynamics of retrobulbar blood vessels in central serous chorioretinopathy].

OBJECTIVE: To analyze the characteristics of the retrobulbar blood vessels' hemodynamics changes and the choroidal circulation disorder, and to observe the relations between retinal pigment epithelium's (RPE) pathological changes and them. METHODS: It was a case control study. For 57 (57 affected eyes and 57 contralateral eyes) unilateral eye affected patients and 25 (50 eyes) normal health adults, we examined ophthalmic arteries (OA), posterior ciliary arteries (PCA) and short posterior ciliary arteries (SPCA) by color Doppler flow Imaging (CDFI), and recorded the peak systolic velocities (PSV), end diastolic velocities (EDV) and resistance indexes (RI) of them. We compared each hemodynamic parameter of the normal eyes with it of the affected eyes and contralateral eyes in patients group respectively, and contrasted them between affected eyes and contralateral eyes of the patients. Fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were performed simultaneously on 57 patients with Heidelberg retina angiography, and the images were analyzed in contrast. We used SPSS 12.0 statistics software was used in the study. To the PSV, EDV and RI of the OA, PCA and SPCA in affected eyes and contralateral eyes of the patients, we used paired t-test for the same sample to compare their hemodynamic parameters; to compare normal health adults' eyes with the affected eyes and the contralateral eyes of patients group respectively, we used two-group t-test. When the P-value was less than 0.05, there was a statistical significance. RESULTS: There was a more significant decrease of the hemodynamic parameters in both PSVs and EDVs of temporal PCAs (PSV: t = 3.044, P = 0.005; EDV: t = 3.731, P = 0.001) and temporal SPCAs (PSV: t = 2.822, P = 0.008; EDV: t = 3.194, P = 0.003) compared the patients group's affected eyes with normal health adults group eyes, there was a more significant decrease of them of temporal PCAs (PSV: t = 3.219, P = 0.003; EDV: t = 3.807, P = 0.001) and temporal SPCAs (PSV: t = 3.931, P = 0.000, EDV: t = 3.145, P = 0.003) compared the patients group's contralateral eyes with normal health adults group eyes, and there was a statistical significance of them (P < 0.05). There was no difference in hemodynamic parameters of both PSVs and EDVs of temporal PCAs (PSV: t = 0.608, P = 0.548; EDV: t = 0.122, P = 0.904) and temporal SPCAs (PSV: t = 0.730, P = 0.470; EDV: t = 0.109, P = 0.914) between affected eyes and contralateral eyes of the patients, and there was no statistical significance of them (P > 0.05). The results of FFA and ICGA showed that all the RPE's leaks of 57 affected eyes appeared at the hypofluorescent regions of relative choroids; 52 cases of 57 affected eyes were followed by choroidal vessels dilatation at the early hypofluorescent regions, and appeared hyperfluorescence leakages in the late phase images; At the all regions of RPE's transmitted fluorescences of affected eyes and contralateral eyes, the corresponding choroids showed hyperfluorescence in the late phase images in ICGA; There were no RPE's transmitted fluorescences at the regions of 20 affected eyes and 16 contralateral eyes in FFA, which showed hyperfluoresceince leakages in the late phase images of choroids in ICGA. CONCLUSIONS: CSC is possibly a bilateral disease associated with systemic pathologic conditions. Hypoperfusion and ischemia are the basal characteristics of retrobulbar blood vessels' circulation disorder and choroidal ultracirculation disorder. The damage of RPE is following to the choroidal circulation disorder.

Targeting acetyl-CoA carboxylases: small molecular inhibitors and their therapeutic potential.

Acetyl-CoA carboxylases (ACCs) play a rate-limiting role in fatty acid biosynthesis in plants, microbes, mammals and humans. ACCs have the activity of both biotin carboxylase (BC) and carboxyltransferase (CT), catalyzing carboxylation of Acetyl-CoA to malonyl-CoA. In the past years, ACCs have been used as targets for herbicides in agriculture and for drug discovery and development of human diseases, such as microbial infections, diabetes, obesity and cancer. A great number of small molecule ACC inhibitors have been developed, including natural and non-natural (artificial) products. These chemicals target BC reaction, CT reaction or ACC phosphorylation. This article provides a comprehensive review and updates of ACC inhibitors, with a focus on their therapeutic application in metabolic syndromes and malignant diseases. The patent status of common ACC inhibitors is discussed.

[Color Doppler ultrasonic measurements of normal mesenteric lymph nodes in healthy children].

OBJECTIVE: To assess the value of color Doppler ultrasound in evaluating the mesenteric lymph nodes in healthy children. METHODS: The mesenteric lymph nodes were examined with color Doppler ultrasonography for 730 randomly selected healthy children under 14 years of age, including 410 boys and 298 girls who did not report any recent medical conditions. RESULTS: Abdominal lymph node detection rate was higher in boys than in girls. Abdominal lymph nodes were detected most often in children between the ages of 1 and 4 years, and the lymph node size decreased gradually with age. CONCLUSION: Color Doppler ultrasonography is valuable for evaluating abdominal lymph nodes in children.

[Enlarged mesenteric lymph nodes in children: a clinical analysis with ultrasonography and the implications].

OBJECTIVE: To compare the enlarged mesenteric lymph nodes in healthy children with those children with mesenteric lymphadenitis. METHODS: According to the diagnostic criteria defining lymph node enlargement as a 5-mm enlargement or greater in the short diameter, 137 healthy children and 148 children with mesenteric lymphadenitis were retrospectively analyzed for mesenteric lymph node enlargement based on the ultrasonographic data. RESULTS: The distribution of enlarged mesenteric lymph nodes was detected in the right lower quadrant (RLQ) in 46.3%, in the para-aortic areas in 19.2%, and in the left lower quadrant (LLQ) in 13.6% of the children. The clusters of lymph nodes between the two groups showed no significant difference in the distribution, age, L/W, longitudinal diameter or clusters, only the short diameter differed significantly between them. CONCLUSION: Enlarged mesenteric lymph nodes are present in many healthy children, which does not necessarily suggests any abnormalities. The mesenteric lymph nodes increase with the age until 6 years and then decrease. The lymph nodes with a short diameter larger than 8 mm may indicate the condition of mesenteric lymphadenitis.