AflaILVB/G/I and AflaILVD are involved in mycelial production, aflatoxin biosynthesis, and fungal virulence in Aspergillus flavus.

Aflatoxins (AFs) are produced by fungi such as Aspergillus flavus and A. parasiticus and are one of the most toxic mycotoxins found in agricultural products and food. Aflatoxin contamination, which requires the control of A. flavus, remains problematic because of the lack of effective strategies and the exploration of new compounds that can inhibit A. flavus growth and mycotoxin production is urgently required to alleviate potential deleterious effects. Acetohydroxy acid synthase (AHAS) and dihydroxy acid dehydratase are important enzymes in the biosynthetic pathways of branched-chain amino acids (BCAAs), including isoleucine, leucine, and valine. Enzymes involved in BCAA biosynthesis are present in bacteria, plants, and fungi, but not in mammals, and are therefore, attractive targets for antimicrobial and herbicide development. In this study, we characterized AflaILVB/G/I and AflaILVD, which encode the catalytic and regulatory subunits of AHAS and dihydroxy acid dehydratase, from the pathogenic fungus Aspergillus flavus. The AflaILVB/G/I and AflaILVD deletion mutant grew slower and produced smaller colonies than the wild-type strain when grown on glucose minimal medium, potato dextrose agar, and yeast extract medium for three days at 28°C, and disruption of AflaILVB/G/I caused a significant reduction in conidia production when grown on all kinds of media. Cellular stress assays determined that all strains were sensitive to H2O2. Importantly, the pathogenicity and aflatoxin production were affected when AflaILVB/G/I and AflaILVD were knocked out, particularly AflaILVB/G/I. A series of genes that encoded enzymes involved in aflatoxin synthesis were downregulated, meaning that the knockout of AflaILVB/G/I influenced aflatoxin synthesis in A. flavus strain WT. Collectively, our results demonstrate the potential value of antifungals targeting AflaILVB/G/I in A. flavus.

Fluid-structure interaction study on the causes of mending material damage after sigmoid sinus wall reconstruction.

BACKGROUND AND OBJECTIVE: Sigmoid Sinus (SS) Wall Reconstruction (SSWR) is the mainstream treatment for pulsatile tinnitus (PT), but it has a high risk of recurrence. The damage of mending material is the key cause of recurrence, and its hemodynamic mechanism is still unclear. The purpose of this study was to investigate the hemodynamic causes of mending material breakage. METHODS: In this study, six patient-specific geometric models were reconstructed based on the data of the computed tomography angiography (CTA). The transient fluid-structure coupling method was performed to clarify the hemodynamic state of sigmoid sinus and the biomechanical state of the mending material. The distribution of stress and displacement and the flow pattern were calculated to evaluate the hemodynamic and biomechanics difference at the mending material area. RESULTS: The area of blood flow impact in some patients (2/6) was consistent with the damaged location of the mending material. The average stress (6/6) and average displacement (6/6) of damaged mending material were higher than those of complete mending material. All (6/6) patients showed that the high-stress and high-displacement proportion of the DMM region was higher than that of the CMM region. Moreover, the average stress fluctuation (6/6) and average displacement (6/6) fluctuation degree of damaged mending material is larger than that of complete mending material. CONCLUSIONS: The impact of blood and the uneven stress and displacement fluctuation of the mending material may be the causes of mending material damage. High stress and high displacement might be the key causes of the mending material damage.

Hemodynamic study on the therapeutic effects of varying diameter embolic coils in the treatment of intracranial aneurysms.

Endovascular coiling is the predominant method for treating cerebral aneurysms. Extensive reports on selecting coil length, hardness, and material are available. However, the impact of coil diameter on postoperative outcomes remains unclear. This study enrolled six personalized geometric models of intracranial aneurysms: three bifurcation aneurysms and three sidewall aneurysms. Four coil models were constructed by changing the coil diameter. Coil embolization was simulated using the finite element method. Computational fluid dynamics was used to characterize hemodynamics in the aneurysms after embolization. Evaluation parameters included velocity reduction, wall shear stress (WSS), low WSS (LWSS), oscillatory shear index (OSI), relative residence time (RRT), and residual flow volume in the aneurysms. At the peak time (t = 0.17 s), the proportion of LWSS area in bifurcation aneurysms increase with the rise in coil diameter: 0.8D, 71.28 ± 12.62% versus 1D, 74.97 ± 19.17% versus 1.2D, 78.88 ± 18.56% versus 1.4D, 84.00 ± 11.53% (mean ± SD). The proportion of high OSI area decreases as the coil diameter increases: 0.8D, 4.41% ± 2.82% versus 1.0D, 3.78 ± 3.33% versus 1.2D, 2.28% ± 1.77% versus 1.4D, 1.58% ± 1.11% (mean ± SD). The proportion of high RRT area increases as the coil diameter rises: 0.8D, 3.40% ± 1.68% versus 1.0D, 7.67 ± 4.12% versus 1.2D, 9.84% ± 9.50% versus 1.4D, 22.29% ± 14.28% (mean ± SD). Side wall aneurysms do not exhibit the aforementioned trend. Bifurcation aneurysms plugged with a coil of 1.4 times the diameter have the largest RFVs (<10 mm/s) within the group. Aforementioned patterns are not found in sidewall aneurysms. In the treatment of aneurysms with coiling, varying coil diameters can result in different hemodynamic environments within the aneurysm. Larger coil diameters have improved hemodynamic performance for bifurcation aneurysms. However, coil diameter and embolization effectiveness have no significant relationship for sidewall aneurysms.

Transcriptomic and Proteomic Insights into the Effect of Sterigmatocystin on Aspergillus flavus.

Aspergillus flavus is an important fungus that produces aflatoxins, among which aflatoxin B1 (AFB1) is the most toxic and contaminates food and poses a high risk to human health. AFB1 interacts with another mycotoxin sterigmatocystin (STC), which is also a precursor of AFB1. Herein, we determined the effect of STC on AFB1 by evaluating A. flavus transcriptomic and proteomic profiles in the presence or absence of STC by RNA-seq and isobaric tagging, respectively. Overall, 3377 differentially expressed genes were identified by RNA-seq. These genes were mainly associated with the cellular component organisation and biosynthesis, the synthesis of valine, leucine, and isoleucine, and the synthesis of aflatoxin. Clustered genes responsible for AFB1 biosynthesis exhibited varying degrees of downregulation, and norB expression was completely suppressed in the experimental group. During proteomic analysis, 331 genes were differentially expressed in response to STC. These differentially expressed proteins were associated with cell parts and catalytic and antioxidant activities. Differentially expressed proteins predominantly participated in metabolic pathways associated with aflatoxin biosynthesis, glycolysis/gluconeogenesis, glutathione metabolism, and carbon metabolism. Notably, the upregulated and downregulated enzymes in carbohydrate and glutathione metabolisms may serve as potential gateways for inhibiting aflatoxin biosynthesis. Moreover, twelve proteins including seven downregulated ones involved in aflatoxin biosynthesis were identified; among them, AflG was the most downregulated, suggesting that it may be the key enzyme responsible for inhibiting aflatoxin synthesis. These findings provide novel insights into A. flavus control and the mechanisms regulating mycotoxin production.

Identification and yield of metabolites of chlorinated paraffins incubated with chicken liver microsomes: Assessment of their potential to convert into metabolites.

Chlorinated paraffins (CPs) are emerging environmental pollutants. Although metabolism has been shown to affect the differential accumulation of short-chain (SCCPs), medium-chain (MCCPs) and long-chain (LCCPs) CPs in birds, CP metabolites have rarely been reported and the extent to which they are formed is still unclear. In this study, single and mixed CP standards were incubated with chicken liver microsomes in vitro to study the generation of CP metabolites. Putative aldehyde/ketone and carboxylic acid metabolites identified by mass spectroscopy data were shown to be false positive results. Phase I metabolism of CPs first formed monohydroxylated ([M-Cl+OH]) and then dihydroxylated ([M-2Cl+2OH]) products. The yields of monohydroxylated metabolites of CPs decreased with increasing carbon chain length and chlorine content at the initial stage of reaction. Notably, the yield of monohydroxylated metabolites of SCCPs with 51.5% Cl content reached 21%, and that of 1,2,5,6,9,10-hexachlorodecane (C10H16Cl6) was as high as 71%. Thus, monohydroxy metabolites of CPs in birds should not be ignored, especially those of SCCPs. This study provides important data that could support improvements to the ecological/health risk assessment of CPs.

Study on Characteristics and Lignification Mechanism of Postharvest Banana Fruit during Chilling Injury.

The banana is prone to chilling injury (CI) at low temperature and showing a series of chilling symptoms, such as peel browning, etc. Lignification is a response to abiotic stress and senescence, which is an important manifestation of fruits and vegetables during chilling exposure. However, little is known about the lignification of bananas during low-temperature storage. Our study explored the characteristics and lignification mechanism of banana fruits during low-temperature storage by analyzing the changes of chilling symptoms, oxidative stress, cell wall metabolism, microstructures, and gene expression related to lignification. The results showed that CI inhibited post-ripening by effecting the degradation of the cell wall and starch and accelerated senescence by increasing O2- and H2O2 content. For lignification, Phenylalanine ammonia-lyase (PAL) might start the phenylpropanoid pathway of lignin synthesis. Cinnamoyl-CoA reductase 4 (CCR4), cinnamyl alcohol dehydrogenase 2 (CAD2), and 4-coumarate--CoA ligase like 7 (4CL7) were up-regulated to promote the lignin monomer's synthesis. Peroxidase 1 (POD1) and Laccase 3 (LAC3) were up-regulated to promote the oxidative polymerization of lignin monomers. These results suggest that changes of the cell wall structure and cell wall metabolism, as well as lignification, are involved in the senescence and quality deterioration of the banana after chilling injury.

Intramedullary nail fixation assisted by locking plate for complex subtrochanteric femur fractures: A retrospective study.

BACKGROUND: This study aims to compare therapeutic effects of two methods in complicated subtrochanteric femur fractures surgery: intramedullary nail fixation assisted with lateral monocortical locking plate versus intramedullary nail fixation assisted with supplementary cables. METHODS: From June 2015 to June 2020, seventy-seven patients with complex subtrochanteric fractures (i.e., Seinsheimer's classification type IV or V) were included in this study. Thirty-six patients (plate group) were operated using the intramedullary nail fixation assisted by lateral monocortical locking plate, and forty-one patients (cable group) were using the intramedullary nail fixation assisted by cables. The clinical information and demographic results were collected and compared. RESULTS: Operation time of plate group was shorter than cable group and the Incisions length of plate group was longer. The fluoroscopy times were 22.8 ± 8.2 in plate group and 33.0 ± 9.0 in cable group (p < 0.01). Compared with the cable group, patients in plate group used less cerclage cables (p < 0.01). Patients in the plate group has less medial cortex displacement compared with the cable group. (p = 0.038). As for the angular difference of neck shaft angle between operated hip and uninjured hip, plate group has less difference compared with the cable group. Time to union was 14.2 ± 3.1 weeks in plate group which is shorter than the cable group (17.9 ± 4.8 weeks). In terms of follow up period, number of malunion, Harris hip score, walking ability and traumatic hip rating scale, no significant differences were detected. CONCLUSIONS: Our results suggest that using lateral monocortical plate as an auxiliary way may have a longer surgical incision and more intraoperative blood loss, however, the operation time is shorter, the fluoroscopy times is less, and the time to union is shorter. Intramedullary nail fixation assisted by lateral monocortical locking plate may be a new option for patients with complex subtrochanteric femur fractures.

Polydopamine and hyaluronic acid immobilisation on vancomycin-loaded titanium nanotube for prophylaxis of implant infections.

Titanium nanotube (Ti-NT) is an attractive substrate for local drug delivery, however, it is difficult to control the burst drug release and achieve sustained release from these nanotubes. In the present study, we investigated the feasibility of controlling drug release from Ti-NT within polydopamine and hyaluronic acid films, to achieve antibacterial activity and osteogenic promotion. Vancomycin was loaded into the Ti-NT by lyophilisation. Dopamine and hyaluronic acid were immobilized on the vancomycin-loaded Ti-NT surface through alternate deposition technique. The anti-infective and osteogenic abilities of the polydopamine and hyaluronic acid-modified Ti-NT were then investigated. Our results demonstrated that polydopamine and hyaluronic acid-modified Ti-NT exhibited improved drug loading and release control for 7 days. Compared with the vancomycin-loaded Ti-NT, the polydopamine and hyaluronic acid-modified Ti-NT exhibited better antibacterial ability, and the hyaluronic acid-modified Ti-NT promoted the osteogenic differentiation of rat bone marrow stem cells. Our results demonstrated that Ti-NT biofunctionalized with polydopamine and hyaluronic acid can help overcome the limitations of Ti-NT, by improving drug loading, antibacterial activity and osteogenic ability.

Impact of persistent subclinical hypothyroidism on clinical outcomes in non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention.

BACKGROUND: Data on the association of subclinical hypothyroidism (SCH) with the severity of coronary artery disease and major adverse cardiovascular and cerebral events (MACCE) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) after percutaneous coronary intervention (PCI) are limited and conflicting. OBJECTIVE: We established the baseline rate of SCH and followed the trajectory of thyroid-stimulating hormone (TSH) values during and after hospitalisation for PCI for up to six months and determined whether persistent SCH was associated with the severity of coronary artery disease and MACCE in patients with NSTE-ACS after PCI. DESIGN: Population-based prospective cohort study. PATIENTS: We included patients with NSTE-ACS who underwent PCI with simple balloon angioplasty or stent implantation for coronary heart disease. MEASUREMENTS: Thyroid function tests of patients before PCI and 1 day, 1 week, 1 and 6 months after PCI were performed. Cases showing transient SCH were excluded. Patients were divided into two groups based on the results of four TSH tests: 0.27-4.2 mIU/L (n = 1472, 89.7%) and >4.2 mIU/L (n = 170, 10.4%). The risk factors for the severity of coronary artery lesions were estimated using multinomial logistic regression analysis. Univariate and multivariate Cox regression analyses were used to study the relationship between TSH and MACCE. RESULTS: Among 1642 patients, there were 1070 males (65.2%) and 572 females (34.8%), with an average age of 62.5 ± 9.6 years. SCH patients had a wider range of diseased vessels and a higher number of diseased vessels (p < .05). TSH level was an independent risk factor for moderate [odds ratio (OR) = 1.144, 95% confidence interval (95% CI): 1.057-1.237, p = .001] and severe (OR = 1.131, 95% CI: 1.043-1.226, p = .003) coronary artery lesions. After adjusting for covariates, the risk of MACCE [hazard ratio (HR): 4.067, p < .001], nonfatal myocardial infarction (HR: 14.724, p = .003), and unplanned PCI (HR: 5.028, p < .001) were higher in the SCH group than in the euthyroidism group. There were no significant differences in the incidence of heart failure (HR: 6.012, p = .175), nonfatal stroke (HR: 2.039, p = .302), unplanned coronary artery bypass grafting (CABG) (HR: 1.541, p = .57), or cardiac death (HR: 2.704, p = .375) between the two groups. CONCLUSIONS: Preoperative TSH levels and changes in thyroid hormone levels several months post-PCI in NSTE-ACS patients are highly significant in practice. Persistent SCH is associated with severe coronary artery lesions and MACCE, and may be a predictor for evaluating the prognosis of PCI-treated NSTE-ACS patients.

Microplastics Environmental Effect and Risk Assessment on the Aquaculture Systems from South China.

The small size of microplastics and their wide distribution in water environments have attracted worldwide attention and heated discussion, because of their ingestion by aquatic organisms. At present, there are few studies on microplastics pollution in freshwater aquaculture ponds, especially shrimp ponds. In this study, the aquaculture ponds in the Pearl River Estuary were investigated. The abundance and composition of microplastics in different environmental media were studied to explore the potential sources and risk levels of microplastics, so as to provide basic data for the study of microplastics pollution in aquaculture ponds. Microplastics were observed in water and sediment samples at all sampling sites, with the abundance of 6.6 × 103-263.6 × 103 items/m3 (surface water) and 566.67-2500 items/kg (sediment), respectively. Thirty-seven individuals collected in six ponds belong to four species. Microplastics were observed in the gastrointestinal tract (GIT) of all fishes and shrimps, with the abundance ranging from 3-92 items/individual (fish) and 4-21 items/individual (shrimp). Among all samples, microplastics with the size range of <1 mm and fiber shape were the most common. The main microplastic components were cellulose, polypropylene (PP), and polyethylene (PE). The results of potential risk assessment showed that the pollution investigation of microplastics should not only consider the abundance. Low abundance does not mean low risk. Taking the toxicity score and abundance of microplastics as evaluation indexes to reflect the pollution status of microplastics may make the results more reliable.

Toxicological effects of microplastics and phenanthrene to zebrafish (Danio rerio).

The toxicology of microplastics in combination with other pollutants has attracted widespread attention. In this study, zebrafish were exposed to 3 mg/L polystyrene microplastic, 0.2 mg/L phenanthrene, and a combination of both. Zebrafish microplastic uptake, phenanthrene accumulation, antioxidant-associated enzyme activity and related gene expression, immune-associated gene expression, and the gut microflora were measured after 12 and 24 days of exposure. Phenanthrene and microplastic accumulation increased with exposure time and was also greater in the combined exposure group than in the single exposure group. Combined analysis of antioxidant enzyme activity and immune and antioxidant-related genes shows that exposure alone causes oxidative stress in zebrafish, ultimately increasing immunity and the expression of oxidative stress genes, while combined exposure exacerbates these changes. Fusobacteria decreased and Proteobacteria and Bacteroidetes increased in the three exposure groups of gut microorganisms. Overall, our study demonstrates that microplastics enhance the toxicity of phenanthrene and that the two have a synergistic effect.

Risk factors for and predictive nomogram of postoperative hypoxaemia in elderly patients with femoral neck fractures.

OBJECTIVE: To investigate the related risk factors and predictive nomogram of postoperative hypoxaemia in elderly patients with femoral neck fractures. METHODS: This study included patients aged ≥65 years who underwent surgical treatment of acute femoral neck fractures. Univariate and multivariate logistic analyses were performed to determine the incidence of and risk factors for postoperative hypoxaemia. A predictive nomogram was constructed based on the multivariable model. Using the bootstrap method, discrimination was determined by the C-index and calibration plot. RESULTS: The logistic regression analysis showed that the anaesthesia type, surgical procedure, American Society of Anesthesiologists (ASA) classification, preoperative hypoxaemia occurrence, and age were independent predictors of development of postoperative hypoxaemia. The predictive formula for hypoxaemia was established as follows: hypoxaemia=-0.8668×spinal anaesthesia (whether)+0.1162×nerve anaesthesia (whether)+1.9555×plate/screw fixation (whether)+1.4950×hip replacement (whether)+0.4883×ASA classification+1.7153×preoperative oxygenation index+0.1608×age. With the bootstrap method, the prediction curve fit well with the ideal curve, suggesting that the prediction curve constructed in this study has good predictive ability. CONCLUSIONS: Anaesthesia type, surgical procedure, ASA classification, preoperative hypoxaemia occurrence, and age were risk factors for postoperative hypoxaemia in elderly patients with femoral neck fractures. The predictive nomogram was designed for preoperative assessment of the risk of postoperative hypoxaemia by calculating the risk score.

WSV152 induces apoptosis and promotes viral replication in Litopenaeus vannamei.

Previous studies have indicated that white spot syndrome virus (WSSV) infection induces apoptosis in many shrimp organs. However, the mechanism by which WSSV causes host apoptosis remains largely unknown. In this study, we demonstrated the function of wsv152, the first mitochondrial protein identified as encoded by WSSV. Glutathione S-transferase pulldown and co-immunoprecipitation analysis revealed that wsv152 interacts with the shrimp mitochondrial protein cytochrome c oxidase 5a (COX5a), a subunit of the COX complex. We also found that wsv152 expression significantly increased the rate of apoptosis, suggesting a role of wsv152 in WSSV-induced apoptosis in shrimp. Knockdown of wsv152 in vivo led to downregulation of several apoptosis-related shrimp genes, including cytochrome c, apoptosis-inducing factor and caspase-3. Suppression of wsv152 also resulted in significant reductions in the number of WSSV genome copies in tissues and in the mortality of WSSV-infected shrimp. Together, these results suggest that wsv152 targets host COX5a and is associated with the expression profiles of apoptosis-related shrimp genes. Wsv152 is likely also involved in WSSV-induced apoptosis, thereby facilitating virus infection and playing a complex role in WSSV pathogenesis.

Hidden blood loss after hip hemiarthroplasty using the superPATH approach: A retrospective study.

OBJECTIVE: The purpose of this study was to compare perioperative hidden blood loss after hip hemiarthroplasty via the SuperPATH approach and the conventional posterior approach (the Moore approach). PATIENTS AND METHODS: From January 2015 to January 2017, 130 patients (80.7 ±â€¯6.0 years) with displaced femoral neck fracture (Garden type III or IV) undergoing hip hemiarthroplasty were included in this study. As a non-randomisation study, Fifty-two patients (SuperPATH group) were operated using the SuperPATH approach, and 78 patients (Moore group) were operated with the conventional posterior approach (Moore approach). The demographic and relevant clinical information of the patients were collected. According to the combination formulas of Nadler, Gross and Sehat, the hidden blood loss (HBL) of each patient was calculated. Student's t-test for independent samples was used to compare the normally distributed variables and the Mann-Whitney U test was used to compare variables not following a normal distribution. RESULTS: The visible blood loss (VBL) in the SuperPATH group was 123.7 ±â€¯47.5 ml, the hidden blood loss (HBL) was 1084.1 ±â€¯816.8 ml and the HBL% was 82.7 ±â€¯16.5%. In the Moore group, the VBL was 303.6 ±â€¯139.6 ml, the HBL was 700.2 ±â€¯563.8 ml and the HBL% was 61.5 ±â€¯23.8%. The patients in the SuperPATH group had more HBL and HBL% (P < 0.05). However, no significant difference was observed of total blood loss (TBL) between the two groups (P = 0.125). CONCLUSIONS: HBL should not be ignored in patients who underwent hip hemiarthroplasty for displaced femoral neck fractures, as it is a significant portion of TBL. Compared with the conventional approach, the SuperPATH approach had a greater amount of HBL. A better understanding of HBL after hip hemiarthroplasty may help surgeons improve clinical assessment and ensure patient safety.

Occurrence of antibiotics and their associations with antibiotic resistance genes and bacterial communities in Guangdong coastal areas.

The concentration of 8 antibiotics and 21 antibiotic resistance genes were investigated in the coastal areas of Guangdong, China. Total concentrations of antibiotics ranged from 0.43 ng/L to 1040.31 ng/L. The concentrations of tetracyclines were much higher than that of sulfonamides in most sampling sites. The abundance of target antibiotic resistance genes ranged from 1.82 × 105 to 5.9 × 109 copies/mL and tetM accounted for the highest percentages of detected antibiotic resistance genes in most sampling sites. Furthermore, the dominant phyla in water samples were Proteobacteria, Bacteroidetes and Actinobacteria. The relationship between antibiotics, antibiotic resistance genes, and bacterial communities was also investigated. As a result, the abundance of sul1 was positively correlated with the concentration of sulfadiazine, sulfamethoxazole and sulfonamide p-methyl oxypyrimidine. Besides, sulfonamide p-methyl oxypyrimidine, sulfadiazine and p-aminobenzenesulfonamide were significantly correlated with the bacterial communities. These findings suggested that the residues of antibiotics in coastal areas of Guangdong affect the distribution of antibiotic resistance genes and alter the microbial communities.

Distribution characteristics of microplastics in Zhubi Reef from South China Sea.

As a new type of emerging pollutant in the ocean, microplastics have received global attention in recent years. Considering the increasing amount of human activities around the South China Sea, it is important to determine the current status of microplastic pollution in this region. In this study, we analyzed the abundance and distribution of microplastics at Zhubi Reef in the South China Sea. Microplastic abundance ranged from 1400 to 8100 items/m3 of surface water, which was much higher than the values reported from other ocean areas. About 80% of the microplastics were smaller than 0.5 mm in size. Fibers and pellets comprised the most common microplastic types. The dominant microplastics were transparent or blue in color. The main polymer types were polypropylene (25%) and polyamide (18%). In general, our results revealed Zhubi Reef was contaminated with microplastics, which were likely derived from the intensive fisheries in the area and emissions from coastal cities. This study also provides baseline data that are useful for additional studies of microplastics in the South China Sea.

Microplastic pollution in water and fish samples around Nanxun Reef in Nansha Islands, South China Sea.

Nanxun Reef is one of the typical reefs in Nansha Islands, South China Sea. As the Nansha Islands are surrounded by certain developing countries, the economic and population growth have resulted in increased surface runoff of persistent organic pollutants in offshore areas. Microplastic has been found in many freshwaters and sea areas in recent years. However, the levels of microplastics contamination in Nansha Islands are still uncharted. In this study, 15 water and 35 fish samples were collected around the Nanxun Reef. The average concentration of microplastics was 1733 items/m3 for surface water samples and 3.1 items per individual for fish samples. The majority of ingested microplastics by fish were fibers, mostly transparent or blue. In surface water samples, blue microbeads were the main types of microplastics, accounting for 76.5% of all the detected particles. The main size of microplastics was <0.5 mm both in water and fish samples. Our results demonstrated that fishery activities and human domestic sewage might be the dominant sources of microplastic pollution in the Nansha Island, South China Sea.

Complete genome sequence of Paracoccus denitrificans ATCC 19367 and its denitrification characteristics.

Studies show that Paracoccus denitrificans can denitrify nitrogen sources under aerobic conditions. However, the lack of data on its genome sequence has restricted molecular studies and practical applications. In this study, the complete genome of P. denitrificans ATCC 19367 was sequenced and its nitrogen metabolism properties were characterized. The size of the whole genome is 5 242 327 bp, with two chromosomes and one plasmid. The average G + C content is 66.8%, and it contains 5308 protein-coding genes, 54 tRNA genes, and nine rRNA operons. Among the protein-coding genes, 71.35% could be assigned to the Gene Ontology (GO) pathway, 86.66% to the Clusters of Orthologous Groups (COG) pathway, and 50.57% to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Comparative genome analysis between P. denitrificans ATCC 19367 and P. denitrificans PD1222 revealed that there are 428 genes specific to ATCC 19367 and 4738 core genes. Furthermore, the expression of genes related to denitrification, biofilm formation, and nitrogen metabolism (nar, nir, and nor) by P. denitrificans ATCC 19367 under aerobic conditions was affected by incubation time and shaking speed. This study elucidates the genomic background of P. denitrificans ATCC 19367 and suggests the possibility of controlling nitrogen pollution in the environment by using this bacterium.

Microplastic abundance, distribution and composition in the Pearl River along Guangzhou city and Pearl River estuary, China.

Like many urban rivers, the Pearl River in China is contaminated with microplastics. Compared with marine environments, microplastic pollution in freshwater is less understood, especially in urban rivers. In the present study, the abundance and distribution of microplastics in water from the Pearl River was investigated, including the estuary and the urban section along Guangzhou. The average abundance of microplastics was 19,860 items/m3 and 8902 items/m3 in the urban section and estuary, respectively. Wastewater effluents from cities might be a main source of microplastics in the Pearl River, and the urban tributaries might act as retention systems for microplastics. Among these microplastics, over 80% of them were less than 0.5 mm. The main shapes of microplastics were film, fragment, and fiber, mostly blue or transparent. Moreover, the most common polymer types of these microplastics were polyamide (26.2%) and cellophane (23.1%). This study reveals the contamination and characteristics of microplastics in the Pearl River, and provides important data for further research on microplastics in freshwater ecosystems.

Clinical effects and risk factors of far cortical locking system in the treatment of lower limb fractures.

INTRODUCTION: This study aims to analyze clinical effects between far cortical locking (FCL) system and standard plating techniques in the treatment of lower limb fractures and identify potential preoperative risk factors for complications in patients treated with FCL system. METHOD: We retrospectively analyzed 76 patients treated with FCL system (the study group) and 68 patients treated with standard plating techniques (the control group) between January 2014 and January 2017. Patients were followed up for a minimum of one year. Surgery-related complications, fixation features, fracture healing rates, the radiographic union scores, and knee functions (Kolment scores) were analyzed between the two groups in the study. Besides, we analyzed eight preoperative characteristics for surgery-related complications, including age, gender, presence of risk factors affecting bone healing, cause of injury, AO/OTA fracture classifications, facture sites, presence of open fractures, and presence of bone losses. RESULTS: The distributions of baseline date were similar between the two groups (P＞0.05). The average number of FCL screws was 4.5 (range: 3-9) in the study group. The average time to union was 2.8 ± 0.9 months in the study group and 3.6 ± 1.0 months in the control group (P＜0.001), and average time to whole weight bearing was 2.3 ± 0.8 months and 2.8 ± 1.2 months, respectively (P = 0.004). Regarding radiographic union score, the study group scores were significantly higher than the control group scores at 1 and 3 months after surgery (P＜0.001), while it becomes insignificant between the two groups at 6 and 12 months after surgery (P = 0.19 and P = 0.15).The working lengths, fracture healing rates, complication rates, and Kolment scores were similar between the two groups (P＞0.05). In the multivariate analysis, fracture sites (OR = 5.34; 95% CI, 1.11-25.75; P = 0.03) and presence of open fractures (OR = 6.19; 95% CI, 1.05-36.38; P = 0.04) were significant associated with complications, whereas other variables were not included. DISCUSSION: FCL system can truly accelerating bone healing and allow earlier whole weight bearing. Fracture healing rates and complication rates were similar between patients treated with FCL implants or conventional plating techniques. Patients with shaft fractures and open fractures trended to have higher complication rates. CONCLUSIONS: FCL system is superior to standard plating technique in terms of early callus formation, but standard plating technique is not inferior to FCL system in terms of final fracture healing, surgery-related complication, and function outcome. Fracture site and presence of open fracture are the independent factors for complications in patients treated with FCL system.