Optimization of sporulation and purification methods for sporicidal efficacy assessment on Bacillus spores.

Validating the efficacy of sporicidal agents is a critical step in current good manufacturing practices for disinfection requirements. A limitation is that the poor quality of spores can lead to false positive sporicidal results. The aim of this study was to explore optimal sporulation and purification methods in Bacillus spores. Spores of 7 Bacillus strains were produced in 5 different sporulation media. After density centrifugation, spore yields were measured by phase-contrast microscopy and enumeration assays. Effects of purification methods including heat, sonication and lysozyme, and maturation on spore qualities were determined by sodium hypochlorite sporicidal assay. Difco sporulation media was identified as the preferred sporulation medium for 4 out of 7 tested Bacillus strains. Sporulation rates in B. cereus, B. sphaericus, and B. thuringiensis were higher at 30°C than the rates at 37°C at a difference of 5%, 65%, and 20%, respectively. Bacillus licheniformis favored Mn2+-amended 10% Columbia Broth at 37°C for sporulation with 40-72% higher sporulation rates than other media. The maximum sporulation rates of B. cereus and B. thuringiensis were observed on double-strength Schaeffer's-glucose broth. All studied purification methods improved the spore purity with strain variations. However, intense heat (80°C for 20 min) and lysozyme (100 µg/mL) treatment impaired the spore quality of specific Bacillus strains by sensitizing them against sodium hypochlorite. The length of the maturation period had an impact on the spore resistance, and the most optimal maturation periods ranged from 7 to 21 days in Bacillus strains. The results of this study will pave the way for further evaluation of the sporicidal activity of disinfectants.

PASS versus MBT™ for evaluation of anchorage control in three-dimensional measurements: a randomized controlled trial.

BACKGROUND: Growth and development might lead to anchorage loss during orthodontic treatment, such as the mesial drift of molars, the compensation characteristics of upper molars following mandibular growth, or the angulation of molars before treatment. Different anchorage reinforcement devices have been developed to prevent mechanical anchorage loss, but the anchorage loss resulting from physiological factors should also be taken into account. OBJECTIVE: To explore the efficacy of a new strategy to control physiologic anchorage compared with that of the conventional straight-wire appliance. TRIAL DESIGN: Randomized controlled trial (RCT). METHODS: Participants of Han ethnicity were randomized into the physiologic anchorage spee-wire system (PASS) group or McLaughlin-Bennett-Trevisi (MBT™) straight-wire group by minimization random allocation. The eligibility criteria were patients with a Class I or II molar relationship, permanent dentition (11-35 years old), fixed appliances involving the extraction of at least two upper first premolars, and medium or maximum anchorage requirements. Pre-treatment and post-treatment dental casts were scanned into digital casts and measured using a blinded method. Mesial displacements of the upper first molars were considered as the primary outcome for evaluating anchorage control. Measurements were taken for subgroups based on age. RESULTS: Data from 60 participants were analysed. The baseline characteristics were not significantly different between groups. Mesial displacement of the upper first molar (in mm) was 2.96 ± 1.52 in the PASS group and 2.70 ± 1.66 in the MBT group (P = 0.521). The variation in incisor torque was -6.94 ± 6.35 degree in the PASS group and -11.76 ± 7.65 degree in the MBT group (P = 0. 010). The incisor retraction (in mm) was 4.24 ± 1.99 and 5.67 ± 2.27 in the PASS and MBT groups, respectively (P = 0.012). Adverse effects were not documented in any patient. LIMITATION: The study was a single-centre study. CONCLUSIONS: Compared with the MBT group, the PASS group without additional anchorage devices could attain well anchorage control by considering the dentoalveolar compensation of anchor teeth. REGISTRATION: This RCT was registered at the Chinese Clinical Trial Registry (Chictr.org.cn) ChiCTR-TRC-13003260.

Phylogenetically diverse bacteria isolated from tattoo inks, an azo dye-rich environment, decolorize a wide range of azo dyes.

PURPOSE: There has been an interest in the microbial azo dye degradation as an optional method for the treatment of azo dye-containing wastes. Tattoo ink is an extremely unique azo dye-rich environment, which have never been explored in terms of microorganisms capable of degrading azo dyes. Previously, we isolated 81 phylogenetically diverse bacteria, belonging to 18 genera and 52 species, contaminated in tattoo inks. In this study, we investigated if these bacteria, which can survive in the azo dye-rich environment, have an ability to degrade azo dyes. METHODS: We conducted a two-step azo dye degradation (or decolorization) assay. In step 1, a high-throughput degradability assay was done for 79 bacterial isolates using Methyl Red and Orange II. In step 2, a further degradation assay was done for 10 selected bacteria with a representative of 11 azo dyes, including 3 commercial tattoo ink azo dyes. Degradation of azo dyes were calculated from measuring optical absorbance of soluble dyes at specific wavelengths. RESULTS: The initial high-throughput azo dye assay (step 1) showed that 79 isolates had a complete or partial degradation of azo dyes; > 90% of Methyl Red and Orange II were degraded within 24 h, by 74 and 20 isolates, respectively. A further evaluation of azo dye degradability for 10 selected isolates in step 2 showed that the isolates, belonging to Bacillus, Brevibacillus, Paenibacillus, and Pseudomonas, exhibited an excellent decolorization ability for a wide range of azo dyes. CONCLUSIONS: This study showed that phylogenetically diverse bacteria, isolated from azo dye-rich tattoo inks, is able to degrade a diverse range of azo dyes, including 3 azo dyes used in commercial tattoo inks. Some of the strains would be good candidates for future studies to provide a systematic understanding of azo dye degradation mechanisms.

[Current Status of and Challenges in Diagnosis and Treatment of Childhood Diffuse Parenchymal Lung Diseases/Childhood Interstitial Lung Diseases].

The medical field in China has witnessed encouraging progress in specialized theoretical research and clinical practice concerning childhood diffuse parenchymal lung diseases/childhood interstitial lung diseases (chDPLD/chILD) after many years of hard work. However, we have also encountered many tasks and challenges. We must approach the problem with a holistic perspective, and collect, accumulate and analyze, in a uniform way, the data from all over the country. We should try our best to obtain more pathological materials for further analysis of the diagnosis and treatment as well as clinical research. The diagnosis protocol and treatment recommendations should be revised regularly. Moreover, we emphasize the adoption of the clinico-radio-genetic-pathological (C-R-G-P) management model and the multi-disciplinary team (MDT) approach to the diagnosis and treatment of chDPLD/chILD. In this way, we will be able to improve our cognitive understanding and enrich our experience in the prevention and management of chDPLD/chILD further more.

Smokeless tobacco impacts oral microbiota in a Syrian Golden hamster cheek pouch carcinogenesis model.

The use of smokeless tobacco products (STPs) can cause many serious health problems. The oral microbiota plays important roles in oral and systemic health, and the disruption in the oral microbial population is linked to periodontal disease and other health problems. To assess the impact of smokeless tobacco on oral microbiota in vivo, high-throughput sequencing was used to examine the oral microbiota present in Syrian Golden hamster cheek pouches. Sixteen hamsters were divided into four groups and treated with the STP Grizzly snuff (0, 2.5, 25, or 250 mg) twice daily for 4 weeks. After 0, 1, 2, 3, and 4 weeks of treatment, bacterial genomic DNA was extracted from oral swabs sampled from the cheek pouches of the hamsters. The oral bacterial communities present in different hamster groups were characterized by sequencing the hypervariable regions V1-V2 and V4 of 16S rRNA using the Illumina MiSeq platform. Fifteen phyla, 27 classes, 59 orders, 123 families, and 250 genera were identified from 4,962,673 sequence reads from the cheek pouch samples. The bacterial diversity and taxonomic abundances for the different treatment groups were compared to the non-treated hamsters. Bacterial diversity was significantly decreased after 4 weeks of exposure to 2.5 mg, and significantly increased by exposure to 250 mg STP. Treatment with 250 mg STP significantly increased Firmicutes, transiently increased Cyanobacteria and TM7, and decreased Bacteroidetes and Fusobacteria compared to the control group. At the genus level, 4 weeks of administration of 250 mg STP significantly increased Granulicatella, Streptococcus, Oribacterium, Anaerococcus, Acidaminococcus, Actinomyces, Eubacterium, Negativicoccus, and Staphylococcus, and decreased Bacteroides, Buleidia, Dialister, and Leptotrichia, and transiently decreased Arcanobacterium compared to the control group. For the first time, an animal model was used for evaluating the effects of STP on oral microbiota by metagenomic sequencing. Our results provide a view of the shift of the oral microbiota in response to STP exposure in Syrian Golden hamster. Our findings indicate that the use of smokeless tobacco significantly disrupts the oral microbiota.

Nonsurgical treatment of Brodie bite assisted by 3-dimensional planning and assessment.

This case report describes the nonsurgical treatment of an adolescent patient with a severe transverse discrepancy presented as a Brodie bite and retrognathic mandible. Distraction osteogenesis has been often used for similar cases in the literature. However, in this patient, a fixed appliance with 1 maxillary extraction combined with a functional appliance was used to resolve the transverse discrepancy with natural growth. After the orthodontic treatment, the impinging teeth and Brodie bite were corrected with a favorable occlusion and profile. Retention at the 3-year follow-up showed improved occlusal interdigitation and good stability.

Longitudinal eruptive and posteruptive tooth movements, studied on oblique and lateral cephalograms with implants.

INTRODUCTION: The purpose of this study was to investigate the eruptive and posteruptive tooth displacements of untreated growing subjects longitudinally and the potential connections between posteruptive displacement of the maxillary and mandibular first molars and skeletal facial growth. METHODS: The sample comprised 11 series of right 45° oblique cephalograms and lateral cephalograms of untreated children with metallic implants of the Björk type obtained from the archives of a growth study. Cephalograms generated at approximately 2-year intervals between the ages of 8.5 and 16 years were selected and traced. Superimpositions of serial tracings of oblique cephalograms on stable intraosseous implants were made to determine the displacements of buccal segment teeth in both arches, and superimpositions of serial tracings of lateral cephalograms were used to evaluate growth of the jaws. RESULTS: Continuous mesial tipping of the maxillary molars was observed from 8.5 to 16 years of age, averaging 8.2° ± 5.5° for the first molars and 18.3°± 8.5° for the second molars. Compared with the maxillary molars, the mandibular first molars showed less change in angulation except in the later mixed dentition when more than half of the subjects had accelerated forward tipping of the first molar in the late mixed dentition associated with migration into the leeway space. Average amounts of cumulative eruption from 8.5 to 16 years of age were 12.1 ± 2.1 mm downward and 3.8 ± 1.7 mm forward for the maxillary first molar. The mandibular first molar showed 8.6 ± 2.3 mm of eruption and 4.4 ± 1.9 mm of mesial migration. Peak velocity of vertical eruption of the maxillary and mandibular first molars corresponded to the skeletal vertical growth spurt. The maxillary canines and first premolars showed remarkable and continuous uprighting migration during eruption, averaging 9.5° ± 5.0° and 10.5° ± 6.7°, respectively. However, when they erupted into the occlusion, their changes in angulation reverted to forward tipping. The same tendency was also found in the mandibular canines and first premolars. CONCLUSIONS: Remarkable eruption and migration occur to the teeth of both arches during childhood and adolescence. Rates of first molar eruption during adolescence follow the general pattern of somatic growth. We infer that maintaining the original distal crown angulation of the maxillary molars may be an effective protocol for preservation of anchorage.

Evaluation of metabolism of azo dyes and their effects on Staphylococcus aureus metabolome.

Dyes containing one or more azo linkages are widely applied in cosmetics, tattooing, food and drinks, pharmaceuticals, printing inks, plastics, leather, as well as paper industries. Previously we reported that bacteria living on human skin have the ability to reduce some azo dyes to aromatic amines, which raises potential safety concerns regarding human dermal exposure to azo dyes such as those in tattoo ink and cosmetic colorant formulations. To comprehensively investigate azo dye-induced toxicity by skin bacteria activation, it is very critical to understand the mechanism of metabolism of the azo dyes at the systems biology level. In this study, an LC/MS-based metabolomics approach was employed to globally investigate metabolism of azo dyes by Staphylococcus aureus as well as their effects on the metabolome of the bacterium. Growth of S. aureus in the presence of Sudan III or Orange II was not affected during the incubation period. Metabolomics results showed that Sudan III was metabolized to 4-(phenyldiazenyl) aniline (48%), 1-[(4-aminophenyl) diazenyl]-2-naphthol (4%) and eicosenoic acid Sudan III (0.9%). These findings indicated that the azo bond close to naphthalene group of Sudan III was preferentially cleaved compared with the other azo bond. The metabolite from Orange II was identified as 4-aminobenzene sulfonic acid (35%). A much higher amount of Orange II (~90×) was detected in the cell pellets from the active viable cells compared with those from boiled cells incubated with the same concentration of Orange II. This finding suggests that Orange II was primarily transported into the S. aureus cells for metabolism, instead of the theory that the azo dye metabolism occurs extracellularly. In addition, the metabolomics results showed that Sudan III affected energy pathways of the S. aureus cells, while Orange II had less noticeable effects on the cells. In summary, this study provided novel information regarding azo dye metabolism by the skin bacterium, the effects of azo dyes on the bacterial cells and the important role on the toxicity and/or inactivation of these compounds due to microbial metabolism.

Effect of smokeless tobacco products on human oral bacteria growth and viability.

To evaluate the toxicity of smokeless tobacco products (STPs) on oral bacteria, seven smokeless tobacco aqueous extracts (STAEs) from major brands of STPs and three tobacco-specific N-nitrosamines (TSNAs) were used in a growth and viability test against 38 oral bacterial species or subspecies. All seven STAEs showed concentration-dependent effects on the growth and viability of tested oral bacteria under anaerobic culture conditions, although there were strain-to-strain variations. In the presence of 1 mg/ml STAEs, the growth of 4 strains decreased over 0.32-2.14 log10 fold, while 14 strains demonstrated enhanced growth of 0.3-1.76 log10 fold, and the growth of 21 strains was not significantly affected. In the presence of 10 mg/ml STAEs, the growth of 17 strains was inhibited 0.3-2.11 log10 fold, 18 strains showed enhanced growth of 0.3-0.97 log10 fold, and 4 strains were not significantly affected. In the presence of 50 mg/ml STAEs, the growth of 32 strains was inhibited 0.3-2.96 log10 fold, 8 strains showed enhanced growth of 0.3-1.0 log10 fold, and 2 strains were not significantly affected. All seven STAEs could promote the growth of 4 bacterial strains, including Eubacterium nodatum, Peptostreptococcus micros, Streptococcus anginosus, and Streptococcus constellatus. Exposure to STAEs modulated the viability of some bacterial strains, with 21.1-66.5% decrease for 4 strains at 1 mg/ml, 20.3-85.7% decrease for 10 strains at 10 mg/ml, 20.0-93.3% decrease for 27 strains at 50 mg/ml, and no significant effect for 11 strains at up to 50 mg/ml. STAEs from snuffs inhibited more tested bacterial strains than those from snus indicating that the snuffs may be more toxic to the oral bacteria than snus. For TSNAs, cell growth and viability of 34 tested strains were not significantly affected at up to 100 µg/ml; while the growth of P. micros was enhanced 0.31-0.54 log10 fold; the growth of Veillonella parvula was repressed 0.33-0.36 log10 fold; and the cell viabilities of 2 strains decreased 56.6-69.9%. The results demonstrate that STAEs affected the growth of some types of oral bacteria, which may affect the healthy ecological balance of oral bacteria in humans. On the other hand, TSNAs did not significantly affect the growth of the oral bacteria.

Differential gene expression in Staphylococcus aureus exposed to Orange II and Sudan III azo dyes.

We previously demonstrated the effects of azo dyes and their reduction metabolites on bacterial cell growth and cell viability. In this report, the effects of Orange II and Sudan III on gene expression profiling in Staphylococcus aureus ATCC BAA 1556 were analyzed using microarray and quantitative RT-PCR technology. Upon exposure to 6 µg/ml Orange II for 18 h, 21 genes were found to be differently expressed. Among them, 8 and 13 genes were up- and down-regulated, respectively. Most proteins encoded by these differentially expressed genes involve stress response caused by drug metabolism, oxidation, and alkaline shock indicating that S. aureus could adapt to Orange II exposure through a balance between up and down regulated gene expression. Whereas, after exposure to 6 µg/ml Sudan III for 18 h, 57 genes were differentially expressed. In which, 51 genes were up-regulated and 6 were down-regulated. Most proteins encoded by these differentially expressed genes involve in cell wall/membrane biogenesis and biosynthesis, nutrient uptake, transport and metabolite, and stress response, suggesting that Sudan III damages the bacterial cell wall or/and membrane due to binding of the dye. Further analysis indicated that all differentially expressed genes encoded membrane proteins were up-regulated and most of them serve as transporters. The result suggested that these genes might contribute to survival, persistence and growth in the presence of Sudan III. Only one gene msrA, which plays an important role in oxidative stress resistance, was found to be down-regulated after exposure to both Orange II and Sudan III. The present results suggested that both these two azo dyes can cause stress in S. aureus and the response of the bacterium to the stress is mainly related to characteristics of the azo dyes.

A comparison of conventional methods for the quantification of bacterial cells after exposure to metal oxide nanoparticles.

BACKGROUND: Due to potential interference of nanoparticles on bacterial quantification, there is a challenge to develop a fast, accurate and reproducible method for bacterial quantification. Currently various bacterial quantification methods are used by researchers performing nanoparticles study, but there has been no efficacy evaluation of these methods. Here we study interference of nanoparticles on three most commonly used conventional bacterial quantification methods, including colony counting to determine the colony-forming units (CFU), spectrophotometer method of optical density (OD) measurement, and flow cytometry (FCM). RESULTS: Three oxide nanoparticles including ZnO, TiO2, and SiO2 and four bacterial species including Salmonella enterica serovar Newport, Staphylococcus epidermidis, Enterococcus faecalis, and Escherichia coli were included in the test. Results showed that there is no apparent interference of the oxide nanoparticles on quantifications of all four bacterial species by FCM measurement; CFU counting is time consuming, less accurate and not suitable for automation; and the spectrophotometer method using OD measurement was the most unreliable method to quantify and detect the bacteria in the presence of the nanoparticles. CONCLUSION: In summary, FCM measurement proved to be the best method, which is suitable for rapid, accurate and automatic detection of bacteria in the presence of the nanoparticles.

Effects of nicotine on proliferation and survival in human umbilical cord mesenchymal stem cells.

Cigarette smoking is known to have negative effects on tissue repair and healing. The aim of this study is to investigate the effects of nicotine in human umbilical cord mesenchymal stem cells (MSCs). After nicotine treatment, MSCs became pyknotic, vacuoles appeared in the cytoplasm and nucleus, and the nuclear boundary became fuzzy as observed using atomic force microscopy. Cell proliferation was inhibited in a dose-dependent manner (P < 0.05 for all concentrations). The proportion of apoptotic MSCs was significantly increased in a dose-dependent manner. The mitochondrial membrane potential was significantly decreased (P < 0.05). Nicotine-treated MSCs had a significantly higher G0/G1 ratio (P < 0.05). Peptide mass fingerprinting identified 27 proteins that were differentially expressed between MSCs with and without nicotine treatment. These nicotine exerted toxic effects on MSCs are likely related, at least in part, to the altered expression of multiple proteins that are essential to the health and proliferation of these cells.

Identification of the enzyme responsible for N-acetylation of norfloxacin by Microbacterium sp. Strain 4N2-2.

Microbacterium sp. 4N2-2, isolated from a wastewater treatment plant, converts the antibacterial fluoroquinolone norfloxacin to N-acetylnorfloxacin and three other metabolites. Because N-acetylation results in loss of antibacterial activity, identification of the enzyme responsible is important for understanding fluoroquinolone resistance. The enzyme was identified as glutamine synthetase (GS); N-acetylnorfloxacin was produced only under conditions associated with GS expression. The GS gene (glnA) was cloned, and the protein (53 kDa) was heterologously expressed and isolated. Optimal conditions and biochemical properties (K(m) and V(max)) of purified GS were characterized; the purified enzyme was inhibited by Mn(2+), Mg(2+), ATP, and ADP. The contribution of GS to norfloxacin resistance was shown by using a norfloxacin-sensitive Escherichia coli strain carrying glnA derived from Microbacterium sp. 4N2-2. The GS of Microbacterium sp. 4N2-2 was shown to act as an N-acetyltransferase for norfloxacin, which produced low-level norfloxacin resistance. Structural and docking analysis identified potential binding sites for norfloxacin at the ADP binding site and for acetyl coenzyme A (acetyl-CoA) at a cleft in GS. The results suggest that environmental bacteria whose enzymes modify fluoroquinolones may be able to survive in the presence of low fluoroquinolone concentrations.

Probing the NADH- and Methyl Red-binding site of a FMN-dependent azoreductase (AzoA) from Enterococcus faecalis.

AzoA from Enterococcus faecalis is a member of the polymeric flavin-dependent NADH-preferred azoreductase group. Little is known about the binding and interaction of NADH and azo dye in the azoreductase group. A synergetic strategy based on computational prediction, reverse genetics validation coupled with site-directed mutagenesis, and reconstruction of mutation network was used to investigate the binding and interaction of NADH and a model azo dye, Methyl Red, with AzoA. Methyl Red and NADH interacted in a unique binding mode in which the benzoic acid moiety of Methyl Red and the nicotinamide ring of NADH were not parallel to the flavin isoalloxazine ring, but lay against it at angles of ∼45° and ∼35°, respectively. The adenine ribose moiety of NADH was surrounded by loop ℓ2 on chain B and α3 on chain A in a typical Rossmann fold. There were 12 and 19 amino acid residues that could participate in the binding of Methyl Red and NADH, respectively, especially the residues Tyr-129 and Asp-184. The functional perturbation effects of 13 residues, including Tyr-129 and Asp-184, were mapped to reconstruct the mutation network, which confirmed the proposed binding modes and also provided insights into the interaction among NADH, FMN and Methyl Red.

Evaluation of impact of exposure of Sudan azo dyes and their metabolites on human intestinal bacteria.

Sudan azo dyes are banned for food usage in most countries, but they are illegally used to maintain or enhance the color of food products due to low cost, bright staining, and wide availability of the dyes. In this report, we examined the toxic effects of these azo dyes and their potential reduction metabolites on 11 prevalent human intestinal bacterial strains. Among the tested bacteria, cell growth of 2, 3, 5, 5, and 1 strains was inhibited by Sudan I, II, III, IV, and Para Red, respectively. At the tested concentration of 100 µM, Sudan I and II inhibited growth of Clostridium perfringens and Lactobacillus rhamnosus with decrease of growth rates from 14 to 47%. Sudan II also affected growth of Enterococcus faecalis. Growth of Bifidobacterium catenulatum, C. perfringens, E. faecalis, Escherichia coli, and Peptostreptococcus magnus was affected by Sudan III and IV with decrease in growth rates from 11 to 67%. C. perfringens was the only strain in which growth was affected by Para Red with 47 and 26% growth decreases at 6 and 10 h, respectively. 1-Amino-2-naphthol, a common metabolite of the dyes, was capable of inhibiting growth of most of the tested bacteria with inhibition rates from 8 to 46%. However, the other metabolites of the dyes had no effect on growth of the bacterial strains. The dyes and their metabolites had less effect on cell viability than on cell growth of the tested bacterial strains. Clostridium indolis and Clostridium ramosum were the only two strains with about a 10 % decrease in cell viability in the presence of Sudan azo dyes. The present results suggested that Sudan azo dyes and their metabolites potentially affect the human intestinal bacterial ecology by selectively inhibiting some bacterial species, which may have an adverse effect on human health.

Integrated Design of Financial Self-Service Terminal Based on Artificial Intelligence Voice Interaction.

Integrated design of financial self-service terminal based on artificial intelligence voice interaction with the rapid development of science and technology, artificial intelligence technology is deepening in the field of intelligence and automation. The financial industry is the lifeblood of a country's economy, with great growth potential and high growth rate. The integrated design of intelligent financial self-service terminal has become an important topic in the field of rapid development of social economy and science and technology. Therefore, this paper designs the integration of financial self-service terminal based on artificial intelligence voice interaction. First, this paper introduces the meaning and composition of financial self-service terminal integration, then studies the voice interaction principle based on artificial intelligence technology, and designs the integrated structure of financial self-service terminal with voice interaction. After that, this paper makes a series of tests on voice interaction technology, user experience, and the performance of financial self-service terminal. Finally, the test results of voice interaction are as follows: the delay estimation results of voice interaction of the terminal are relatively accurate, and the error points are basically within five sampling points, which indicate that the delay estimation algorithm is practical. The endpoint detection method based on CO complexity can effectively overcome the impact of noise environment on speech endpoint detection system and is suitable for the requirements of robust speech recognition system. Considering that the actual application scenario of voice positioning can judge the speaker's position and turn to the speaker's direction during human-computer interaction, the azimuth error is acceptable within a few degrees to meet the application requirements. The direction angle error is acceptable within a few degrees to meet the application requirements. The accuracy of the improved algorithm is improved in intercepting effective speech signals. The terminal has short running time and delay time, small memory, and central processing unit (CPU) occupation and can meet the needs of users. The speech recognition accuracy of the financial self-service terminal basically reaches more than 80%, which can basically meet the daily needs.

Evaluating Cefoperazone-Induced Gut Metabolic Functional Changes in MR1-Deficient Mice.

Mucosal-associated invariant T cells are activated following the recognition of bacterial antigens presented by the major histocompatibility complex class I-related molecule (MR1). Previous metagenomics data showed that MR1-/- knock-out (KO) mice had distinct microbiota and displayed a resistance to Clostridioides difficile (CDI) colonization vs. wild-type (WT) mice. In the present study, LC/MS-based untargeted metabolomics are applied to evaluate the changes in metabolic activities, in accordance with the changes in gut microbiota caused by cefoperazone (Cef) treatment. Adult C57Bl/6J WT and MR1-/- KO mice were given sterile drinking water or spiked with 0.5 mg/mL Cef ad libitum for five days. Fecal pellets were collected daily, and both small intestinal and cecal contents were harvested at sacrifice. The PLS-DA score plots of the metabolomic data indicate that the microbiota is relatively less disturbed by Cef treatment in KO mice, which is consistent with the metagenomics data. The most noticeable differences in the metabolome of KO and WT mice were the increases in carbohydrates in the WT mice, but not in the KO mice. Metabolic functional biomarkers were identified through the correlation analysis of gamma-aminobutyric acid (GABA) and riboflavin. These detected metabolic functional biomarkers could provide information complementary to metagenomics data.

SugE, a new member of the SMR family of transporters, contributes to antimicrobial resistance in Enterobacter cloacae.

We cloned a gene, sugE, from the chromosome of Enterobacter cloacae ATCC 13047. Analysis of the susceptibilities of the sugE-containing strain (Escherichia coli KAM32/pSUGE28) and sugE-deficient E. cloacae (EcΔsugE) showed that SugE confers resistance to cetyltrimethylammonium bromide, cetylpyridinium chloride, tetraphenylphosphonium, benzalkonium chloride, ethidium bromide, and sodium dodecyl sulfate. We also investigated expression of sugE. We confirm here that SugE from E. cloacae is an SMR family transporter as determined by observing its energy-dependent drug efflux activity.

EmmdR, a new member of the MATE family of multidrug transporters, extrudes quinolones from Enterobacter cloacae.

We cloned a gene, ECL_03329, from the chromosome of Enterobacter cloacae ATCC13047, using a drug-hypersensitive Escherichia coli KAM32 cell as the host. We show here that this gene, designated as emmdR, is responsible for multidrug resistance in E. cloacae. E. coli KAM32 host cells containing the cloned emmdR gene (KAM32/pEMMDR28) showed decreased susceptibilities to benzalkonium chloride, norfloxacin, ciprofloxacin, levofloxacin, ethidium bromide, acriflavine, rhodamine6G, and trimethoprim. emmdR-deficient E. cloacae cells (EcΔemmdR) showed increased susceptibilities to several of the antimicrobial agents tested. EmmdR has twelve predicted transmembrane segments and some shared identity with members of the multidrug and toxic compound extrusion (MATE) family of transporters. Study of the antimicrobial agent efflux activities revealed that EmmdR is an H+-drug antiporter but not a Na+ driven efflux pump. These results indicate that EmmdR is responsible for multidrug resistance and pumps out quinolones from E. cloacae.

Effects of Orange II and Sudan III azo dyes and their metabolites on Staphylococcus aureus.

Azo dyes are widely used in the plastic, paper, cosmetics, food, and pharmaceutical industries. Some metabolites of these dyes are potentially genotoxic. The toxic effects of azo dyes and their potential reduction metabolites on Staphylococcus aureus ATCC BAA 1556 were studied. When the cultures were incubated with 6, 18, and 36 µg/ml of Orange II and Sudan III for 48 h, 76.3, 68.5, and 61.7% of Orange II and 97.8, 93.9, and 75.8% of Sudan III were reduced by the bacterium, respectively. In the presence of 36 µg/ml Sudan III, the cell viability of the bacterium decreased to 61.9% after 48 h of incubation, whereas the cell viability of the control culture without the dye was 71.5%. Moreover, the optical density of the bacterial cultures at 10 h decreased from 0.74 to 0.55, indicating that Sudan III is able to inhibit growth of the bacterium. However, Orange II had no significant effects on either cell growth or cell viability of the bacterium at the tested concentrations. 1-Amino-2-naphthol, a metabolite common to Orange II and Sudan III, was capable of inhibiting cell growth of the bacterium at 1 µg/ml and completely stopped bacterial cell growth at 24-48 µg/ml. On the other hand, the other metabolites of Orange II and Sudan III, namely sulfanilic acid, p-phenylenediamine, and aniline, showed no significant effects on cell growth. p-Phenylenediamine exhibited a synergistic effect with 1-amino-2-naphthol on cell growth inhibition. All of the dye metabolites had no significant effects on cell viability of the bacterium.