Optimal balance of organic detritus and feed for fish growth and water quality improvement through regulating nutrients cycling.

In order to explore the effects of different feed composition on the nutrient level and microbial loop structure in aquaculture ponds, a field simulation experiment in aquaculture ponds was conducted by adding different proportions (0%, 20%, 40% and 60%) of bagasse to fish feed for combined feeding. The addition of bagasse significantly reduced the levels of various forms of nitrogen and phosphorus in the water, especially with the addition of 60% bagasse. In the treatments without addition and with 20% bagasse added, nitrogen and phosphorus levels remained relatively high, which should be attributed to the decomposition of feed and the release of sediment, ultimately stimulating the abundant reproduction of algae. Bacterial growth was limited due to insufficient supply of organic carbon, and the growth of fish relied more on the components of the feed. With the addition of 60% bagasse, the high organic carbon and low nitrogen and phosphorus levels could not support the growth of phytoplankton, bacteria, and zooplankton. It is inferred that organic carbon may be more degraded into carbon dioxide, ultimately limiting the growth of fish. Adding 40% bagasse achieved a balanced level of carbon, nitrogen, and phosphorus, establishing a healthy and stable microbial loop structure (including phytoplankton, bacteria, and zooplankton). Most nutrients were converted into plankton, which then became natural food for fish, ensuring complete nutrient utilization. This is beneficial for both water quality improvement and fish reproduction. Therefore, adding a moderate proportion of bagasse to the feed can maximize the effects of water quality improvement, fish reproduction, and even the quality of fish meat.

Microbial Response to Coastal-Offshore Gradients in Taiwan Straits: Community Metabolism and Total Prokaryotic Abundance as Potential Proxies.

Located between the South and the East China Sea, the Taiwan Straits (TWS) are a marine shelf-channel area, with unique hydrological and geomorphological features affected by rivers inflow and with recent algal blooms with red tide events. This study aimed at assessing microbial distribution and function and their modulation in response to environmental gradients. Surface (0.5 m) water samples from 16 stations along five north to south transects were collected; total prokaryotic abundance by epifluorescence microscope and carbon substrate utilization patterns by Biolog Ecoplates were estimated. Spatially, a patchy microbial distribution was found, with the highest microbial metabolic levels and prokaryotic abundance in the TWS area between Minjiang River estuary and Pingtan Island, and progressive decreases towards offshore stations. Complex carbon sources and carbohydrates were preferentially metabolized. This study provides a snapshot of the microbial abundance and activity in TWS as a model site of aquatic ecosystems impacted from land inputs; obtained data highlights that microbial metabolism is more sensitive than abundance to environmental changes.

Regulation of the Nutrient Cycle Pathway and the Microbial Loop Structure by Different Types of Dissolved Organic Matter Decomposition in Lakes.

To explore the effect of different types of dissolved organic matter (DOM) decomposition on nutrient cycling pathways and the microbial loop, four lakes with different DOM sources were investigated monthly. In Lake Tangxun, Dolichospermum decay released highly labile dissolved organic nitrogen into the water column. This induced bacterial organic nitrogen decomposition, as indicated by the increased abundance of gltB, gltD, gdh, and glnA as well as aminopeptidase activity. Genes associated with dissimilatory nitrate reduction to ammonium further fueled ammonium accumulation, driving Microcystis blooms in the summer. In Lake Zhiyin, fish bait deposits (high nitrogen, similar to Dolichospermum detritus) also caused Microcystis blooms. Detritus from Microcystis decomposition then produced high levels of labile dissolved organic phosphorus, inducing phosphatase activity and increasing soluble reactive phosphorus concentrations from September to April in Lakes Tangxun and Zhiyin. The high refractory DOM from macrophytes in Lake Houguan led to insufficient nutrient availability, leading to nutrient mutualism between algae and bacteria. The high levels of labile dissolved organic carbon from terrestrial detritus in Lake Yandong increased bacterial biomass and production, resulting in low chlorophyll content due to the competitive relationship between algal and bacterial nutrient requirements. Therefore, different DOM compositions induce unique connections among available nutrients, algae, and bacteria in the microbial loop.

Metagenomic insights into feasibility of agricultural wastes on optimizing water quality and natural bait by regulating microbial loop.

Effective screening feed substitutes for improving water quality in aquaculture systems has become a trending research topic now. In this study, three typical organic agricultural wastes, including sugar cane bagasse (SC), coconut shell powder (CS), and corn cob powder (CC), were selected to evaluate their potential roles on the optimization of water quality and natural bait compared to aquafeeds. Fish feed resulted in the highest growth rate of fish but the worst water quality. Organic detritus addition markedly improved the water quality, especially soluble reactive phosphorus (SRP, decrease of 56-61%) and ammonium (decrease of 16% in SC, 47% in CC). Specially, SC induced core microbes to mediate nutrients transformation and recycling (N2-fixation, ammonification, nitrification, dissimilatory nitrate reduction to ammonia and organic nutrients decomposition), which facilitated the primary productivity based on their positive relationships. This further reduced the available nutrients (especially SRP) in the water and built a mutually beneficial microbial loop. In addition, SC addition increased the abundance of genes involved in amino acids biosynthesis pathways, photosynthesis, and carbon fixation. These results led to energy transfer to higher trophic levels. The addition of CC had a better effect than SC in terms of lower nitrogen levels and a higher fish growth rate (19% in CC, 5% in SC). However, low temperatures and carbon accumulation jointly drive the anaerobic decomposition, resulting in unhealthy microbial loops and low fish growth rates. In contrast to the direct consumption of fish feed, organic detritus can induce more natural bait to provide food for fish by regulating the microbial loop, as showed by the microbial community composition in the water and fish gut. To comprehensively assess water quality, natural bait, and fish growth and quality, certain organic detritus should be considered as an auxiliary material to partially replace feed for healthy and sustainable aquaculture systems.

Mutual Dependence of Nitrogen and Phosphorus as Key Nutrient Elements: One Facilitates Dolichospermum flos-aquae to Overcome the Limitations of the Other.

Dolichospermum flos-aquae (formerly Anabaena flos-aquae) is a diazotrophic cyanobacterium causing harmful blooms worldwide, which is partly attributed to its capacity to compete for nitrogen (N) and phosphorus (P). Preventing the blooms by reducing P alone or both N and P has caused debate. To test the effects alone and together on the growth of cyanobacteria, we performed culture experiments in different eutrophication scenarios. N2 fixation in terms of heterocyst density, nitrogenase activity and nifH expression increased significantly in P-replete cultures, suggesting that P enrichment facilitates N2 fixation. Correspondingly, the expression of genes involved in P uptake, e.g., those involved in P-transport ( pstS) and the hydrolysis of phosphomonoesters ( phoD), was upregulated in P-deficient cultures. Interestingly, N addition enhanced not only the expression of these genes but also polyphosphate formation and alkaline phosphatase activity in P-deficient cultures relative to the P-replete cultures, as evidenced by qualitative (enzyme-labeled fluorescence) and quantitative (fluorogenic spectrophotometry) measurements. Furthermore, after N addition, cell activity and growth increased in the P-deficient cultures, underscoring the risk of N enrichment in P-limited systems. The eco-physiological responses shown here help further our understanding of the mechanism of N and P colimitation and underscore the importance of dual N and P reduction in controlling cyanobacterial blooms.

Interventions to prevent mother-to-child transmission in breastfeeding mothers with HIV: a systematic review and meta-analysis of randomized controlled trials.

This study aimed to systematically review interventions to prevent mother-to-child transmission of HIV during breastfeeding. We conducted a systematic review and meta-analysis using specific criteria to identify randomized controlled trials that focused on pregnant and breastfeeding women living with HIV and their children from birth to 2 years of age. We extensively searched electronic databases, including Web of Science, Scopus, PubMed, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Google Scholar up to October 24, 2023. After screening 3,110 titles and abstracts, we reviewed 306 full texts. Of these, we assessed the quality and risk of bias of fifty-five articles, ultimately identifying seven studies. Four of these studies, which focused on antiretroviral therapy (ART), were included in the meta-analysis. There was little heterogeneity in study methodology and pooled estimates. The postnatal HIV transmission rate was found to be 0.01 (95%CI: 0.00 - 0.02). Therefore, the risk of mother-to-child transmission among breastfeeding mothers with HIV was significantly lower in the intervention groups than in the placebo groups. Analysis of funnel plots and Egger's test (p = 0.589) showed no evidence of publication bias. In addition to the four articles, two studies compared different ART regimens and one study compared the administration of high-dose vitamin A to the mother or the child. The results suggest that the use of ART significantly reduces the risk of postnatal HIV transmission compared with placebo. However, the effectiveness of different ART regimens or other therapies, including high-dose vitamin A, is unclear.

Relationship between eutrophication and greenhouse gases emission in shallow freshwater lakes.

In shallow lakes, there are complex relationships between lake eutrophication and greenhouse gas emissions that deserve to be studied, which are important for solving lake eutrophication, slowing down climate warming, and reducing carbon emissions. In order to explore the relationship and mechanism between eutrophication and greenhouse gases (GHGs), the net GHGs emission flux and transformation of carbon, and nitrogen in 45 shallow freshwater lakes were investigated from May to September 2022. Eutrophication facilitated potential denitrification rate (Dt) without increasing nitrous oxide (N2O) production based on the significantly positive relationship between eutrophication and Dt. This should be attributed to the shift from incomplete (N2O producing process) to complete denitrification (N2 producing process). Compared to NarG mediating nitrate (NO3-) to nitrite (NO2-), fewer eutrophication indicators showed a positive relationship with NosZ mediating N2O to N2, suggesting that more stringent conditions are required for complete denitrification, which was achieved in the lakes we investigated. Optimal reduction in net carbon dioxide (CO2) emissions occurs at high levels of primary productivity, as indicated by the V-shaped relationship between chlorophyll a (Chl a) and CO2 emissions. However, in hyper-eutrophic lakes, there is an upward trend in CO2 production. The possible explanations should include CO2 production and fixation as well as methane (CH4) oxidation. The bell-shaped relationship between the net flux of CH4 emission and Chl a could be explained that CH4 was heavily oxidized due to sufficient oxygen caused by algal bloom. This fact gave evidence for the increase of the net flux of CO2 emission in high primary productivity lakes. Therefore, the relationship and mechanism between net GHGs emission flux and eutrophication remained complex and various.

A novel strategy of bloom forming cyanobacteria Microcystis sp. in response to phosphorus deficiency: Using non-phosphorus lipids substitute phospholipids.

Despite significant reductions in phosphorus (P) loads, lakes still experience cyanobacterial blooms. Little is known regarding cellular P regulation in response to P deficiency in widely distributed bloom causing species such as Microcystis. In this study, we investigated changes in P containing and non-P lipids contents and their ratios concomitantly with the determinations of expression levels of genes encoding these lipids in cultural and field Microcystis samples. In the culture, the content of phosphatidylglycerol (PG) decreased from 2.1 µg g-1 in P replete control to 1.2 µg g-1 in P-deficient treatment, while non-P lipids, like sulfoquinovosyldiacylglycerol (SQDG) and monogalactosyldiacylglycerol (MGDG), increased dramatically from 13.6 µg g-1 to 142.3 µg g-1, and from 0.9 µg g-1 to 16.74 µg g-1, respectively. The expression of the MGDG synthesis gene, mgdE, also increased under low P conditions. Significant positive relationships between soluble reactive phosphorus (SRP) and ratios of P-containing lipids (PG) to non-P lipids, including SQDG, MGDG and digalactosyldiacylglycerol (DGDG) (P < 0.05) were observed in the field investigations. Both cultural and field data indicated that Microcystis sp. might increase non-P lipids proportion to lower P demand when suffering from P deficiency. Furthermore, despite lipid remodeling, photosynthetic activity remained stable, as indicated by comparable chlorophyll fluorescence and Fv/Fm ratios among cultural treatments. These findings suggested that Microcystis sp. may dominate in P-limited environments by substituting glycolipids and sulfolipids for phospholipids to reduce P demand without compromising the photosynthetic activity. This effective strategy in response to P deficiency meant a stricter P reduction threshold is needed in terms of Microcystis bloom control.

Hydrological regimes and water quality variations in the Yangtze River basin from 1998 to 2018.

Understanding the long-term variations in basins that undergo large-scale hydroelectric projects is crucial for effective dam operation and watershed management. In this study, comprehensive analyses were conducted on a dataset spanning over 20 years (1998-2018) of hydrological regime and physicochemical parameters from the Yangtze River basin to evaluate the potential impacts of the Three Gorges Dam. Water level significantly increased from 128.75±58.18 m in 2002 to 136.78±55.05 m in 2005, and the mean flow velocity significantly decreased from 2004 to 2010. However, no significant change in the flow was observed in the basin. Meanwhile, remarkable fluctuations in physicochemical parameters, including dissolved oxygen, chemical oxygen demand, conductivity, hardness, and alkalinity, were mainly observed during impoundment (2003-2009). After that, the above parameters tended to stabilize, and some even returned to their original levels. The dam's retention effect significantly reduced the suspended solids (SS) in both up- and downstream, to only one-third of the pre-operation level. And total phosphorus and chemical oxygen demand also significantly decreased with the decline of SS. Particularly, ammonium also showed a significant downward trend, with the up- and downstream of the dam falling by 36.8 % and 26.1 %, respectively. However, the increasing total nitrogen (7.5 % and 20.0 % up- and downstream of the dam, respectively) still threatened the water quality of the basin, especially in the estuaries. Additionally, the significant decline in dissolved oxygen downstream (from 8.53±1.08 mg/L to 8.11±1.36 mg/L) also exacerbated the hypoxia in the Yangtze River estuary. The results demonstrated the long-term impact of the construction of the Three Gorges Dam on the environmental elements of the Yangtze River basin, which provides reference data and guidance for the construction of big dams in major rivers in the future.

[Knot-free anchor repair of anterior talofibular ligament under total ankle arthroscopy].

OBJECTIVE: To explore clinical effect of repairing anterior talofibular ligament with knot-free anchors under total ankle arthroscopy in treating chronic lateral ankle instability. METHODS: From April 2018 to August 2021, 24 patients with chronic lateral ankle instability were treated with knot-free anchors under total ankle arthroscopy to repair anterior talofibular ligament, including 16 males and 8 females, aged from 22 to 42 years old with an average of(28.6±5.8) years old;the time from injury to opertaion ranged from 6 to 10 months with an average of(7.7±1.3) months. Preoperative and postoperative American Orhopaedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS), talar tilt, anterior talar translation(ATT) were recorded and compared. RESULTS: All patients were followed up from 10 to 12 months with an average of (10.2±1.14) months. Incision were healed at stageⅠ, and no infection, nerve injury and lateral ankle instability occurred. AOFAS score improved from(52.79±8.96) before opertaion to (93.00± 4.01) at 6 months after operation, 23 patients got excellent result and 1 good;VAS decreased from (5.50±0.98) before opertaion to (1.04±0.80) at 6 months after operation(P<0.05);talar tilt decreased from(9.16±2.09)° to (3.10±1.72)° at 3 months after operation(P<0.05);ATT decreased from(8.80±2.55) mm to (2.98±1.97) mm at 3 months after operation(P<0.05). Twenty-four patients drawer test and varus-valgus rotation wer negative. CONCLUSION: Repairing anterior talofibular ligament with knot-free anchors under total ankle arthroscopy for the treatment of chronic lateral ankle instability has advantages of less trauma, less complications safe and reliable, and good recovery of ankle joint function.

Drought characteristics and dominant factors across China: Insights from high-resolution daily SPEI dataset between 1979 and 2018.

Drought, a complex phenomenon exacerbated by climate change, is influenced by various climate factors. The escalating global temperatures associated with climate change, impact precipitation patterns and water cycle processes, consequently intensifying the occurrence and severity of droughts. To effectively address and adapt to these challenges, it is crucial to identify the dominant climate factors driving drought events. In this study, we utilized the 1979-2018 Chinese meteorological forcing dataset to calculate the daily Standardized Precipitation Evapotranspiration Index (SPEI). The Theil-Sen and Mann-Kendall (M-K) tests were employed to analyze the spatial and temporal trends of drought severity and duration. Additionally, partial correlation analysis was conducted to examine the relationship between climate factors (precipitation and potential evapotranspiration (PET)) and drought characteristic (drought severity and duration). Through this comprehensive analysis, we aimed to identify the primary factors influencing drought severity and duration. The findings revealed the following key results: (1) Over the 40-year period from 1979 to 2018, drought trends in China and its seven climate divisions exhibited an increasing pattern. (2) During drought periods, most regions exhibited a positive correlation between PET and drought severity and duration, while precipitation demonstrated a negative correlation. However, certain areas experiencing severe drought displayed a negative correlation between PET and drought severity and duration, precipitation demonstrated a positive correlation with drought severity and duration. (3) PET emerged as the dominant climatic factor for meteorological drought in the majority of China. These findings contribute valuable insights for policymakers in the development of climate change adaptation and mitigation strategies. By understanding the dominant climate factors driving drought events, policymakers can implement effective measures to mitigate the adverse socioeconomic and environmental impacts associated with climate change.

Diminished schwann cell repair responses play a role in delayed diabetes-associated wound healing.

Diabetes mellitus is the most common metabolic disease associated with impaired wound healing. Recently, Schwann cells (SCs), the glia of the peripheral nervous system, have been suggested to accelerate normal skin wound healing. However, the roles of SCs in diabetic wound healing are not fully understood. In this study, Full-thickness wounds were made in the dorsal skin of C57/B6 mice and db/db (diabetic) mice. Tissue samples were collected at different time points, and immunohistochemical and immunofluorescence analyses were performed to detect markers of de-differentiated SCs, including myelin basic protein, Sox 10, p75, c-Jun, and Ki67. In addition, in vitro experiments were performed using rat SC (RSC96) and murine fibroblast (L929) cell lines to examine the effects of high glucose conditions (50 mM) on the de-differentiation of SCs and the paracrine effects of SCs on myofibroblast formation. Here, we found that, compared with that in normal mice, wound healing was delayed and SCs failed to rapidly activate a repair program after skin wound injury in diabetic mice. Furthermore, we found that SCs from diabetic mice displayed functional impairments in cell de-differentiation, cell-cycle re-entry, and cell migration. In vitro, hyperglycemia impaired RSC 96 cell de-differentiation, cell-cycle re-entry, and cell migration, as well as their paracrine effects on myofibroblast formation, including the secretion of TGF-ß and Timp1. These results suggest that delayed wound healing in diabetes is due in part to a diminished SC repair response and attenuated paracrine effects on myofibroblast formation.

[Risk factors of adjacent vertebral refracture after percutaneous vertebroplasty for osteoporotic vertebral compression fractures in super-old patients].

OBJECTIVE: To analyze the risk factors for refracture of adjacent vertebrae after percutaneous vertebroplasty (PVP) in super-old patients with osteoporotic vertebral compression fractures(OVCFs). METHODS: A retrospective analysis was performed on 40 patients(age≥90 years) with OVCFs who underwent PVP between June 2012 and June 2019. There were 7 males and 33 females, age from 90 to 101 years old with an average of (94.6±1.6) years. Patients were divided into two groups according to whether adjacent vertebral refracture occurred after PVP. Among them, 20 patients occurred refracture after PVP (refracture group) and 20 patients did not occur it(control group). The general information, radiological data and pelvic parameters of the two groups were collected. The items included age, gender, body mass index (BMI), fracture site and bone mineral density(BMD) T-value, fracture to operation time, compression degree of injured vertebra, recovery degree of anterior edge of injured vertebra, bone cement injection amount, bone cement leakage, pelvic index(PI), pelvic tilt angle (PT), sacral angle(SS), et al. Factors that may be related to refracture were included in the single-factor study, and multivariate Logistic regression analysis was performed on the risk factors with statistical significance in the single-factor analysis to further clarify the independent risk factors for refracture of adjacent vertebral bodies after PVP. RESULTS: There were no significant differences in age, gender, fracture site, fracture to operation time, compression degree of injured vertebra and recovery degree of anterior edge of injured vertebra between two groups (P>0.05). There were significant differences in BMI, BMD T-value, bone cement injection amount and bone cement leakage rate between two groups(P<0.05). The PI and PT values of the refracture group were higher than those of the control group(P<0.05). There was no significant difference in SS between two groups (P>0.05). Multivariate Logistic regression analysis showed that decreased BMD T-value, bone cement leakage, increased PT and PI values increased the risk of recurrence of adjacent vertebral fractures in OVCFs (P<0.05). CONCLUSION: There are many risk factors for the recurrence of adjacent vertebral fractures in super-old patients with OVCFs. Patients with high PI and PT values may be one of the risk factors.

Bacterial Communities and Enzymatic Activities in Sediments of Long-Term Fish and Crab Aquaculture Ponds.

Aquaculture is among the most important and fastest growing agriculture sectors worldwide; however, it generates environmental impacts by introducing nutrient accumulations in ponds, which are possibly different and further result in complex biological processes in the sediments based on diverse farming practices. In this study, we investigated the effects of long-term farming practices of representative aquatic animals dominated by grass carp (GC, Ctenopharyngodon idella) or Chinese mitten crab (CMC, Eriocheir sinensis) on the bacterial community and enzyme activity of sediments from more than 15 years of aquaculture ponds, and the differences associated with sediment properties were explored in the two farming practices. Compared to CMC ponds, GC ponds had lower contents of TC, TN, and TP in sediments, and similar trends for sediment pH and moisture content. Sediment bacterial communities were significantly different between GC and CMC ponds, with higher bacterial richness and diversity in GC ponds. The bacterial communities among the pond sediments were closely associated with sediment pH, TC, and TN. Additionally, the results showed profoundly lower activities of ß-1,4-glucosidase, leucine aminopeptidase, and phosphatase in the sediments of GC ponds than CMC ponds. Pearson's correlation analysis further revealed strong positive correlations between the hydrolytic enzyme activities and nutrient concentrations among the aquaculture ponds, indicating microbial enzyme regulation response to sediment nutrient dynamics. Our study herein reveals that farming practices of fish and crab differently affect bacterial communities and enzymatic activities in pond sediments, suggesting nutrient-driven sediment biological processes in aquaculture ponds for different farming practices.

Acquired mucoid phenotype of Acinetobacter baumannii: Impact for the molecular characteristics and virulence.

Mucoid phenotype is an important adaptive defense response for Acinetobacter baumannii (A. baumannii). The aim of this study was to analyze the impact of mucoid phenotype for the molecular characteristics and virulence of A. baumannii. We observed that the colonies of mucoid A. baumannii were moist, with an elevated surface, and the wire drawing result was positive. Transmission electron microscopy data showed that the outer wall of the mucoid colonies was not smooth, had protruding pseudopodia, and was surrounded by a layer of unknown material. Antibiotic susceptibility testing showed that the mucoid strains were multidrug resistant. Notably, the mucoid phenotype and antibiotic resistance were not correlated with the amount of biofilm produced by A. baumannii. MLST data demonstrated that the mucoid A. baumannii strains belonged to type ST2. Most (82.6 %, 38/46) of the multidrug-resistant nonmucoid strains also belonged to the molecular type ST2 and to other types, including ST129, ST158, ST195, ST80 and ST3. Moreover, mucoid A. baumannii strains were more virulent than nonmucoid isolates in a mouse model. The comparative transcriptomic data indicated that 15 genes, especially IX87_RS16955 (acnA), IX87_RS10800 (XanP), IX87_RS12875 (GlmM), IX87_RS00885 and IX87_RS12395 (bfr), were possibly associated with the phenotype and virulence of mucoid A. baumannii. In conclusions, the study comprehensively describes the molecular characteristics and virulence regulatory mechanism of mucoid A. baumannii, and provides novel insights for the prevention and treatment of infections associated with these strains.

Metagenomic insights into co-proliferation of Vibrio spp. and dinoflagellates Prorocentrum during a spring algal bloom in the coastal East China Sea.

Coastal harmful algal blooms (HABs), commonly termed 'red tides', have severe undesirable consequences to the marine ecosystems and local fishery and tourism industries. Increase in nitrogen and/or phosphorus loading is often regarded as the major culprits of increasing frequency and intensity of the coastal HAB; however, fundamental understanding is lacking as to the causes and mechanism of bloom formation despite decades of intensive investigation. In this study, we interrogated the prokaryotic microbiomes of surface water samples collected at two neighboring segments of East China Sea that contrast greatly in terms of the intensity and frequency of Prorocentrum-dominated HAB. Mantel tests identified significant correlations between the structural and functional composition of the microbiomes and the physicochemical state and the algal biomass density of the surface seawater, implying the possibility that prokaryotic microbiota may play key roles in the coastal HAB. A conspicuous feature of the microbiomes at the sites characterized with high trophic state index and eukaryotic algal cell counts was disproportionate proliferation of Vibrio spp., and their complete domination of the functional genes attributable to the dissimilatory nitrate reduction to ammonia (DNRA) pathway substantially enriched at these sites. The genes attributed to phosphorus uptake function were significantly enriched at these sites, presumably due to the Pi-deficiency induced by algal growth; however, the profiles of the phosphorus mineralization genes lacked consistency, barring any conclusive evidence with regard to contribution of prokaryotic microbiota to phosphorus bioavailability. The results of the co-occurrence network analysis performed with the core prokaryotic microbiome supported that the observed proliferation of Vibrio and HAB may be causally associated. The findings of this study suggest a previously unidentified association between Vibrio proliferation and the Prorocentrum-dominated HAB in the subtropical East China Sea, and opens a discussion regarding a theoretically unlikely, but still possible, involvement of Vibrio-mediated DNRA in Vibrio-Prorocentrum symbiosis. Further experimental substantiation of this supposed symbiotic mechanism may prove crucial in understanding the dynamics of explosive local algal growth in the region during spring algal blooms.

Circulating Tumor Cell and Metabolites as Novel Biomarkers for Early-Stage Lung Cancer Diagnosis.

BACKGROUND: Lung cancer is a malignant tumor that has the highest morbidity and mortality rate among all cancers. Early diagnosis of lung cancer is a key factor in reducing mortality and improving prognosis. METHODS: In this study, we performed CTC next-generation sequencing (NGS) in early-stage lung cancer patients to identify lung cancer-related gene mutations. Meanwhile, a serum liquid chromatography-tandem mass spectrometry (LC-MS) untargeted metabolomics analysis was performed in the CTC-positive patients. To screen potential diagnostic markers for early lung cancer. RESULTS: 62.5% (30/48) of lung cancer patients had ≥1 CTC. By CTC NGS, we found that > 50% of patients had 4 commonly mutated genes, namely, NOTCH1, IGF2, EGFR, and PTCH1. 47.37% (9/19) patients had ARIDH1 mutations. Additionally, 30 CTC-positive patients and 30 healthy volunteers were subjected to LC-MS untargeted metabolomics analysis. We found 100 different metabolites, and 10 different metabolites were identified through analysis, which may have potential clinical application value in the diagnosis of CTC-positive early-stage lung cancer (AUC >0.9). CONCLUSIONS: Our results indicate that NGS of CTC and metabolomics may provide new tumor markers for the early diagnosis of lung cancer.

Blooms of diatom and dinoflagellate associated with nutrient imbalance driven by cycling of nitrogen and phosphorus in anaerobic sediments in Johor Strait (Malaysia).

Coastal eutrophication is one of the pivotal factors driving occurrence of harmful algal blooms (HABs), whose underlying mechanism remained unclear. To better understand the nutrient regime triggering HABs and their formation process, the phytoplankton composition and its response to varying nitrogen (N) and phosphorus (P), physio-chemical parameters in water and sediment in Johor Strait in March 2019 were analyzed. Surface and sub-surface HABs were observed with the main causative species of Skeletonema, Chaetoceros and Karlodinium. The ecophysiological responses of Skeletonema to the low ambient N/P ratio such as secreting alkaline phosphatase, regulating cell morphology (volume; surface area/volume ratio) might play an important role in dominating the community. Anaerobic sediment iron-bound P release and simultaneous N removal by denitrification and anammox, shaped the stoichiometry of N and P in water column. The decrease of N/P ratio might shift the phytoplankton community into the dominance of HABs causative diatoms and dinoflagellates.

Community composition and functional genes explain different ecological roles of heterotrophic bacteria attached to two bloom-forming cyanobacterial genera.

Eutrophication leads to frequent outbreaks of cyanobacterial blooms, however, the effect of heterotrophic bacteria attached to cyanobacterial cells is unclear. Field investigations were carried out to gain a deeper understanding of the community composition and functional role of heterotrophic bacteria attached to Dolichospermum and Microcystins cells. The significantly positive relationships between Dolichospermum density and total nitrogen (TN) and between Microcystins density and particle nitrogen (PN) indicated the strong nitrogen (N) demand of these two species. The lack of functional genes that mediate the nitrification process in bacteria attached to both Microcystins and Dolichospermum cells indicated that these two genera preferred ammonium (NH4+-N). Dolichospermum cells obtained more available N through N2 fixation, which was expressed by high nitrogenase gene abundance. Bacteria attached to Microcystins cells showed a higher activity of leucine aminopeptidase and a significantly higher abundance of functional genes that mediate dissimilatory nitrate reduction to ammonium (DNRA) than those attached to Dolichospermum cells. The significantly higher abundance of carbon degradation genes and ß-glucosidase activity of bacteria attached to Microcystins cells compared with those of bacteria attached to Dolichospermum cells suggested that abundant organic carbon was bound to Microcystins cells, which is a prerequisite for DNRA. In addition, Microcystins cells exhibited a great advantage in soluble reactive phosphorus (SRP) production through high levels of organic phosphorus (P) hydrolysis associated with high levels of phosphatase genes of attached bacteria. In conclusion, bacteria attached to Microcystins cells performed more important functions on NH4+-N and SRP production through ammonification and DNRA, as well as phosphatase hydrolysis respectively, compared to those attached to Dolichospermum. Thus, algal growth is the result of different variables such as nutrient concentration, their ratio and the microbial ability.

Metagenomic evidence reveals denitrifying community diversity rather than abundance drives nitrate removal in stormwater biofilters amended with different organic and inorganic electron donors.

Various sole and mixed electron donors were tested to promote the denitrification rate and nitrate removal efficiency in biofilter systems with high phosphate and ammonia removal efficiency (92.6% and 95.3% respectively). Compared to sole electron donors, complex organic carbon (bits of wood and straw) substantially improved the denitrification rate and nitrate removal efficiency (from 6.3%-18.5% to35.4%) by shifting the denitrifying microbial community composition, even though the relative abundance of functional genes mediating denitrification decreased. The mixed electron donor combining complex organic carbon with sulfur, iron and CH4 further promoted nitrate removal efficiency by 37.2%. The significantly higher abundance and diversity of bacteria mediating organic carbon decomposition in the treatments with complex organic carbon indicated the continuous production of organic carbon with small molecular weights, which provided sustainable and effective electron donor for denitrification. However, sole sulfur or iron did not effectively promote the denitrification rate and nitrogen removal efficiency, even though the related microbial community had been formed.