Shewanella xiamenensis sp. nov., isolated from coastal sea sediment

A Gram-negative, motile, rod-shaped bacterium, strain S4 T , was isolated from coastal sediment collected off Xiamen, China. The physiological and biochemical features of strain S4 T , determined using the API 20NE, API ZYM and Biolog GN2 systems, were similar to those of members of the genus Shewanella. Phylogenetic analyses based on 16S rRNA and gyrB gene sequences placed strain S4 T in the genus Shewanella, and it was most closely related to Shewanella oneidensis and related species. DNA-DNA hybridization demonstrated only 11.9-30.4 % relatedness between S4 T and the type strains of related Shewanella species. On the basis of phylogenetic and phenotypic characteristics, strain S

Task-oriented Dialogue System for Automatic Disease Diagnosis via Hierarchical Reinforcement Learning

In this paper, we focus on automatic disease diagnosis with reinforcement learning (RL) methods in task-oriented dialogues setting. Different from conventional RL tasks, the action space for disease diagnosis (i.e., symptoms) is inevitably large, especially when the number of diseases increases. However, existing approaches to this problem employ a flat RL policy, which typically works well in simple tasks but has significant challenges in complex scenarios like disease diagnosis. Towards this end, we propose to integrate a hierarchical policy of two levels into the dialogue policy learning. The high level policy consists of a model named master that is responsible for triggering a model in low level, the low level policy consists of several symptom checkers and a disease classifier. Experimental results on both self-constructed real-world and synthetic datasets demonstrate that our hierarchical framework achieves higher accuracy in disease diagnosis compared with existing systems. Besides, the datasets (http://www.sdspeople.fudan.edu.cn/zywei/data/Fudan-Medical-Dialogue2.0) and codes (https://github.com/nnbay/MeicalChatbot-HRL) are all available now

Fuzzy Controller Based QoS Routing Algorithm with a Multiclass Scheme for MANET

A mobile ad hoc network (MANET) consists of a set of mobile hosts that can communicate with each other without the assistance of base stations. Due to the dynamic nature of the network topology and restricted resources, quality of service (QoS) and multicast routing in MANET are challenging tasks which attract the interests of many people. In this paper, we present a fuzzy controller based QoS routing algorithm with a multiclass scheme (FQRA) in mobile ad hoc networks. The performance of this scheduler is studied using NS2 (Network Simulator version 2) and evaluated in terms of quantitative measures such as packet delivery ratio, path success ratio and average end-to-end delay. Simulations show that the approach is efficient, promising and applicable in ad hoc networks

Development of Food-Luring Baited Traps for Solenopsis invicta (Hymenoptera: Formicidae) Monitoring in the Field in Southern China

Solenopsis invicta Buren (Hymenoptera: Formicidae), a red imported fire ant that originated from South America, is a worldwide invasive pest. This study investigated the efficacy of the newly designed baited trap to detect red imported fire ants, Solenopsis invicta Buren, under field conditions in China. Among the five food lures tested for red imported fire ants, the ants preferred ham sausage and fish powder, followed by mixed powder (50% fish powder + 50% black soldier fly powder) and black soldier fly powder. These lures were compared to sugar water (control) to determine their efficacy in trapping red imported fire ants. Field data revealed that the ham sausage powder trap was more efficient than the fish powder trap based on its ability to trap more red imported fire ants under field conditions and ease of use. Thus, it was concluded that the baited traps are efficient for longterm red imported fire ants monitoring

Efficacy and Safety of Clearing Heat and Detoxifying Injection in the Treatment of Influenza: A Randomized, Double-Blinded, Placebo-Controlled Trial

Objective. To evaluate the efficacy and safety of CHDI in the treatment of influenza infection. Method. A randomized double-blind, double dummy trial was conducted. Influenza patients with a positive influenza A rapid test diagnosis were randomized to receive CHDI or oseltamivir. Primary outcome was assessed by the median fever alleviation time and clearance time, and secondary outcome was total scores of influenza symptoms. Results. One hundred thirty-nine participants were screened and 34 had a RT-PCR laboratory confirmation of influenza virus infection. Fever alleviation time was 2.5 and 5 hours in CHDI and oseltamivir, respectively, and fever clearance time was 32.5 and 49 hours. The HR of fever alleviation and clearance time shows no significant difference between two groups. Total scores of influenza symptoms descended significantly in both groups after treatment and descended more in CHDI than oseltamivir on day 2. Similar to total symptoms severity score, fever severity score descend more significantly in CHDI than oseltamivir on day 2, and there were no differences on other symptoms. Conclusions. CHDI have a similar effect to oseltamivir in reducing the duration of influenza illness. CHDI was well tolerated, with no serious adverse events noted during the study period

Isolation and characterization of Desulfovibrio dechloracetivorans sp. nov., a marine dechlorinating bacterium growing by coupling the oxidation of acetate to the reductive dechlorination of 2-chlorophenol. Appl Environ Microbiol 66

Strain SF3, a gram-negative, anaerobic, motile, short curved rod that grows by coupling the reductive dechlorination of 2-chlorophenol (2-CP) to the oxidation of acetate, was isolated from San Francisco Bay sediment. Strain SF3 grew at concentrations of NaCl ranging from 0.16 to 2.5%, but concentrations of KCl above 0.32% inhibited growth. The isolate used acetate, fumarate, lactate, propionate, pyruvate, alanine, and ethanol as electron donors for growth coupled to reductive dechlorination. Among the halogenated aromatic compounds tested, only the ortho position of chlorophenols was reductively dechlorinated, and additional chlorines at other positions blocked ortho dechlorination. Sulfate, sulfite, thiosulfate, and nitrate were also used as electron acceptors for growth. The optimal temperature for growth was 30°C, and no growth or dechlorination activity was observed at 37°C. Growth by reductive dechlorination was revealed by a growth yield of about 1 g of protein per mol of 2-CP dechlorinated, and about 2.7 g of protein per mole of 2,6-dichlorophenol dechlorinated. The physiological features and 16S ribosomal DNA sequence suggest that the organism is a novel species of the genus Desulfovibrio and which we have designated Desulfovibrio dechloracetivorans. The unusual physiological feature of this strain is that it uses acetate as an electron donor and carbon source for growth with 2-CP but not with sulfate. Substantial amounts of halogenated aromatic compounds have been released to the environment and many of them have accumulated in groundwater and sediments To date, much of the dehalogenation research has been directed toward understanding the fate and behavior of halogenated pollutants in freshwater sediments, soils, and sludges. Comparatively little is known about the fates of these pollutants or dehalogenating organisms from the marine environment despite the fact that marine biota produce a remarkable array of halogenated compounds (12). For example, studies by King (15) indicate that 2,4-dibromophenol occurred at concentrations of up to several hundred micromolar in hemichordate burrow walls and that this chemical was dehalogenated in these sediments under anaerobic conditions. This result suggested that bacterial populations from some marine habitats may have developed enzymatic capabilities to degrade these naturally occurring organohalides. Hence, marine sources may reveal further diversity of dehalogenating microorganisms. Here, we describe enrichment, isolation, and characterization of a novel marine bacterium capable of growth in a synthetic seawater medium on 2-CP and acetate. This new isolate dechlorinates ortho-chlorophenol, producing phenol as a product. Phenotypic and 16S ribosomal DNA (rDNA) phylogenetic studies indicate that the organism belongs to the Desulfovibrio group of the sulfate-reducing bacteria. To our knowledge, this is the first member of the Desulfovibrio group that is capable of oxidizing acetate. MATERIALS AND METHODS Media and growth conditions. Cultures were grown in 160-ml serum bottles with 50 or 100 ml of anaerobic synthetic seawater medium or in 30-ml anaerobic culture tubes with 20 ml of medium. The medium was modified from standard seawater media to remove sulfate so that dechlorinators rather than sulfate reducers could be enriched, and to achieve an Na ϩ concentration of 0.46 M, which approximates that of seawater. It contained the following mineral salts (in grams/liter): NaCl, 25; MgCl 2 , 1.4; KH 2 PO 4 , 0.2; NH 4 Cl, 0.3; KCl, 0.5; and CaCl 2 , 0.1. A trace element solution was added to give the following final concentrations (in milligrams/liter): MnCl 2 ⅐ 6H 2 O, 5; H 3 BO 3 , 0.5; ZnCl 2 , 0.5; CoCl 2 ⅐ 6H 2 O, 0.5; NiSO 4 ⅐ 6H 2 O, 0.5; CuCl 2 ⅐ 2H 2 O, 0.3; and NaMoO 4 ⅐ 2H 2 O, 0.1. In addition, the medium contained 0.003 mg of NaSeO 3 and 0.008 mg of Na 2 WO 4 per liter and 10 mg of resazurin per liter. The medium was boiled under oxygen-free N 2 and cooled to room temperature under N 2 -CO 2 (95:5). Na 2 S (as a reductant) and NaHCO 3 were then added to final concentrations of 1 and 30 mM, respectively, and the pH of the medium was adjusted to 7.3 to 7.5 by varying the CO 2 concentration in the headspace. The medium was dispensed into N 2 -CO 2 -flushed serum bottles or culture tubes capped with butyl rubber stoppers and sterilized by autoclaving. The sterile medium was amended with an anaerobic sterile Wolin vitamin solution (34) plus thiamine, 1,4-naphthoquinone

Prevalence of multidrug-resistant hypervirulent Klebsiella pneumoniae without defined hypervirulent biomarkers in Anhui, China: a new dimension of hypervirulence

Klebsiella pneumoniae is an opportunistic pathogen that mainly causes nosocomial infections and hospital-associated pneumonia in elderly and immunocompromised people. However, multidrug-resistant hypervirulent K. pneumoniae (MDR-hvKp) has emerged recently as a serious threat to global health that can infect both immunocompromised and healthy individuals. It is scientifically established that plasmid-mediated regulator of mucoid phenotype genes (rmpA and rmpA2) and other virulence factors (aerobactin and salmochelin) are mainly responsible for this phenotype. In this study, we collected 23 MDR-hvKp isolates and performed molecular typing, whole genome sequencing, comparative genomic analysis, and phenotypic experiments, including the Galleria mellonella infection model, to reveal its genetic and phenotypic features. Meanwhile, we discovered two MDR-hvKp isolates (22122315 and 22091569) that showed a wide range of hypervirulence and hypermucoviscosity without rmpA and rmpA2 and any virulence factors. In phenotypic experiments, isolate 22122315 showed the highest hypervirulence (infection model) with significant mucoviscosity, and conversely, isolate 22091569 exhibited the highest mucoviscosity (string test) with higher virulence compared to control. These two isolates carried carbapenemase (blaKPC − 2), β-lactamase (blaOXA − 1, blaTEM − 1B), extended-spectrum β-lactamase (ESBL) genes (blaCTX − M − 15, blaSHV − 106), outer membrane protein-coding genes (ompA), fimbriae encoding genes (ecpABCDER), and enterobactin coding genes (entAB, fepC). In addition, single nucleotide polymorphism analysis indicated that both isolates, 22122315 and 22091569, were found to have novel mutations in loci FEBNDAKP_03184 (c. 2084A > C, p. Asn695Thr), and EOFMAFIB_02276 (c. 1930C > A, p. Pro644Thr), respectively. Finally, NCBI blast analysis suggested these mutations are located in the wzc of the capsule polysaccharide (cps) region and are responsible for putative tyrosine kinase. This study would be a strong reference for enhancing the current understanding of identifying the MDR-hvKp isolates that lacked both mucoid regulators and virulence factors