Mallard hindlimbs locomotion system respond to changes in sandy ground hardness and slope.

Mallards inhabit soft grounds such as mudflats, marshes, and beaches, demonstrating remarkable proficiency in traversing these grounds. This adeptness is closely linked to the adjustments in the operation of their hindlimbs. This study employs high-speed videography to observe postural adjustments during locomotion across mudflats. Analysis of spatiotemporal parameters of the hindlimbs reveals transient and continuous changes in joints (tarsometatarso-phalangeal joint (TMTPJ), intertarsal joint (ITJ), knee, and hip) during movement on different ground hardness and slope (horizontal and uphill). The results indicate that as the stride length of the mallard increases, its speed also increases. Additionally, the stance phase duration decreases, leading to a decrease in the duty factor. Reduced ground hardness and increased slope lead to delayed adjustment of the TMTPJ, ITJ, and knee. Mallards adjust their stride length by augmenting ITJ flexion on steeper slopes, while reduced hardness prompts a decrease in TMTPJ flexion at touch-down. Additionally, the hip undergoes two brief extensions during the stance phase, indicating its crucial role in posture adjustment and propulsion on uphill grounds. Overall, the hindlimb joints of the mallard function as a whole musculoskeletal system, with each joint employing a distinct strategy for adjusting to adapt to various ground conditions.

Biomechanical functions analysis of the Mallard webbed foot: A study of macroscopic and microscopic material assembly and tendon morphology.

The mallard webbed foot represents an exemplary model of biomechanical efficiency in avian locomotion. This study delves into the intricate material assembly and tendon morphology of the mallard webbed foot, employing both macroscopic and microscopic analyses. Through histological slices and scanning electron microscopy (SEM), we scrutinized the coupling assembly of rigid and flexible materials such as skin, tendon, and bone, while elucidating the biomechanical functions of tendons across various segments of the tarsometatarsophalangeal joint (TMTPJ). The histological examination unveiled a complex structural hierarchy extending from the external integument to the skeletal framework. Notably, the bone architecture, characterized by compact bone and honeycombed trabeculae, showcases a harmonious blend of strength and lightweight design. Tendons, traversing the phalangeal periphery, surrounded by elastic fibers, collagen fibers, and fat tissue. Fat chambers beneath the phalanx, filled with adipocytes, provide effective buffering, enabling the phalanx to withstand gravity, provide support, and facilitate locomotion. Furthermore, SEM analysis provided insights into the intricate morphology and arrangement of collagen fiber bundles within tendons. Flexor tendons in proximal and middle TMTPJ segments adopt a wavy-type, facilitating energy storage and release during weight-bearing activities. In contrast, distal TMTPJ flexor tendons assume a linear-type, emphasizing force transmission across phalangeal interfaces. Similarly, extensor tendons demonstrate segment-specific arrangements tailored to their respective biomechanical roles, with wavy-type in proximal and distal segments for energy modulation and linear-type in middle segments for enhanced force transmission and tear resistance. Overall, our findings offer a comprehensive understanding of the mallard webbed foot's biomechanical prowess, underscoring the symbiotic relationship between material composition, tendon morphology, and locomotor functionality. This study not only enriches our knowledge of avian biomechanics but also provides valuable insights for biomimetic design and tissue engineering endeavors.

Active Adaptive Strategies of Mallard Feet in Response to Changes in Wetness and Compactness of the Sand Terrain.

Mallards (Anas platyrhynchos) exhibit exceptional locomotive abilities in diverse terrains, such as beaches, swamps, and tidal flats. This capability is primarily attributed to their unique webbed toe structure and cooperative locomotion posture of their feet. Therefore, this study aims to further delve into the active adaptive strategies of mallard feet in response to diverse external environmental conditions. Six adult male mallards were selected for this research. Their locomotion on sandy surfaces with differing wetness levels and varying degrees of compaction were captured using a high-speed camera, and analysis of instantaneous and continuous changes in the primary joint angles of the mallards' feet, including the toe-webbed opening and closing angles, the tarsometatarsal-phalangeal joint (TMTPJ), and the intertarsal joint (ITJ). It was found that on loose sandy surfaces, increasing wetness expanded the ground contact area of the mallards' feet. This led to greater flexion at the TMTPJ joint during mid-stance, accompanied by decreased flexion of the ITJ during touch-down and mid-stance. Conversely, on compacted sand, increasing wetness resulted in a reduced foot effect area and lessened ITJ flexion at both touch-down and mid-stance. Furthermore, on looser sand, the ground contact area of the mallards' feet decreased, with an increase in ITJ buckling at touch-down. During the swing phase, sand wetness and compactness effected minimally on the feet of the mallards. On dry and loose sand ground, mallards will contract their second and fourth toes with webbing upon ground contact, covering and compacting the sand beneath while increasing ITJ flexion to mitigate sinking. This adaptation reduces the energy expended on sand and enhances body stability. In wet and compacted sand conditions, mallards expand their second and fourth toes upon ground contact and reduce ITJ flexion. Therefore, this coordinated foot and ITJ locomotion offers mallards a natural advantage when moving on various environmental media.

The first reported pulmonary nocardiosis caused by Nocardia gipuzkoensis resisted to trimethoprim/sulfamethoxazol (TMP-SMZ) in an immunocompetent patient.

OBJECTIVES: Nocardia gipuzkoensis was first described as a novel and distinct species in 2020 by Imen Nouioui and pulmonary nocardiosis associated with N. gipuzkoensis was once reported in two bronchiectasis patients. Noteworthy, both reported N. gipuzkoensis cases showed sensitivity to trimethoprim/sulfamethoxazol (TMP-SMZ), which are usually recommended for empirical therapy. METHODS: We reported the third case of N. gipuzkoensis infection in a 16-year-old girl with chief complaints of cough and persistent chest and back pain. No underlying immuno-suppressive conditions and glucocorticoid use was revealed. Patchy lesions next to the spine and located in the posterior basal segment of the lower lobes of the left lung were seen in thorax computed tomography (CT), but no pathogenic bacteria were detected according to routine laboratory testings. RESULTS: Metagenomic next-generation sequencing (mNGS) combined with whole-genome sequencing (WGS) was used to classified our isolate from bronchoalveolar lavage fluid (BALF) as N. gipuzkoensis. It is worth mentioning that drug susceptibility testing of our isolate showed resistance to TMP-SMZ, which was never reported before. The patient improved remarkably both clinically and radiographically according to the treatment with imipenem-cilastatin infusion alone. CONCLUSION: mNGS and WGS showed excellent performance in identifying the Nocardia genus to the species level and improving the detection rate of N. gipuzkoensis ignored by traditional culture. Different from previously reported cases, the N. gipuzkoensis infection case showed resistance to TMP-SMZ, which is an unprecedented finding and a crucial addition to our understanding of the antibacterial spectrum of N. gipuzkoensis. The successful treatment with imipenem-cilastatin infusion alone in this case is a testament to the importance of precise identification and tailored antibiotic therapy.

"Internet+Nursing Service" Mobile Apps in China App Stores: Functionality and Quality Assessment Study.

Background: As the Chinese society ages and the concern for health and quality of life grows, the demand for care services in China is increasing. The widespread use of internet technology has greatly improved the convenience and efficiency of web-based services. As a result, the Chinese government has been implementing "Internet+Nursing Services" since 2019, with mobile apps being the primary tools for users to access these services. The quality of these apps is closely related to user experience and the smooth use of services. Objective: This study aims to evaluate the functionality, services, and quality of "Internet+Nursing Service" apps; identify weaknesses; and provide suggestions for improving service programs and the research, development, improvement, and maintenance of similar apps. Methods: In December 2022, two researchers searched for "Internet+Nursing Service" apps by applying the search criteria on the Kuchuan mobile app monitoring platform. After identifying the apps to be included based on ranking criteria, they collected information such as the app developer, app size, version number, number of downloads, user ratings, and number and names of services. Afterward, 5 trained researchers independently evaluated the quality of the apps by using the Chinese version of the user version of the Mobile App Rating Scale (uMARS-C). The total uMARS-C score was based on the average of the five evaluators' ratings. Results: A total of 17 "Internet+Nursing Service" apps were included. Among these, 12 (71%) had been downloaded more than 10,000 times, 11 (65%) had user ratings of 4 or higher, the median app size was 62.67 (range 22.71-103; IQR 37.51-73.47) MB, 16 (94%) apps provided surgical wound dressing change services, 4 (24%) covered first-tier cities, and only 1 (6%) covered fourth-tier cities. The median total uMARS-C score was 3.88 (range 1.92-4.92; IQR 3.71-4.05), which did not correlate with app store user ratings (r=0.003; P=.99). The quality of most apps (11/17, 65%) was average. Most apps (12/17, 71%) were rated as "good" or above (≥4 points) in terms of information quality, layout, graphics, performance, and ease of use; however, the vast majority of apps were rated as "fair" or even "poor" (<4 points) in terms of credibility (14/17, 82%) and demand (16/17, 94%). Conclusions: "Internet+Nursing Service" apps need to broaden their service coverage, increase service variety, and further optimize their service structure. The overall quality of these apps is generally poor. App developers should collaborate with medical professionals and communicate with target users before launching their products to ensure accurate content, complete functionality, and good operation that meets user needs.

Risk factors, outcomes, and epidemiological and etiological study of hospitalized COVID-19 patients with bacterial co-infection and secondary infections.

BACKGROUND: As a common complication of viral respiratory tract infection, bacterial infection was associated with higher mortality and morbidity. Determining the prevalence, culprit pathogens, outcomes, and risk factors of co-infection and secondary infection occurring in hospitalized patients with coronavirus disease 2019 (COVID-19) will be beneficial for better antibiotic management. METHODS: In this retrospective cohort research, we assessed clinical characteristics, laboratory parameters, microbiologic results, and outcomes of laboratory-confirmed COVID-19 patients with bacterial co-infection and secondary infection in West China Hospital from 2022 December 2nd to 2023 March 15th. RESULTS: The incidence of bacterial co-infection and secondary infection, as defined by positive culture results of clinical specimens, was 16.3% (178/1091) and 10.1% (110/1091) respectively among 1091 patients. Acinetobacter, Klebsiella, and Pseudomonas were the most commonly identified bacteria in respiratory tract samples of COVID-19 patients. In-hospital mortality of COVID-19 patients with co-infection (17.4% vs 9.5%, p = 0.003) and secondary infection (28.2% vs 9.5%, p < 0.001) greatly exceeded that of COVID-19 patients without bacterial infection. Cardiovascular disease (1.847 (1.202-2.837), p = 0.005), severe COVID-19 (1.694 (1.033-2.778), p = 0.037), and critical COVID-19 (2.220 (1.196-4.121), p = 0.012) were proved to be risk factors for bacterial co-infection, while only critical COVID-19 (1.847 (1.202-2.837), p = 0.005) was closely related to secondary infection. CONCLUSIONS: Bacterial co-infection and secondary infection could aggravate the disease severity and worsen clinical outcomes of COVID-19 patients. Notably, only critical COVID-19 subtype was proved to be an independent risk factor for both co-infection and secondary infection. Therefore, standard empirical antibiotics was recommended for critically ill COVID-19 rather than all the inpatients according to our research.

Effect of ANKRD49 on migration of human lung adenocarcinoma cells and its mechanism / 中国生物制品学杂志

@#Objective To study the effect of ankyrin repeat domain 49(ANKRD49)on the migration of human lung adenocarcinoma cell line NCI-H1299 and its mechanism.Methods NCI-H1299 cells were infected with lentivirus vector carrying ANKRD49 gene and shRNA targeting ANKRD49 to construct the cell models stably overexpressing and knocking down ANKRD49. Meanwhile,the control cell models infected with empty lentivirus vector and lentivirus vector with scramble sequences were constructed respectively. The expression levels of ANKRD49 mRNA and protein were detected by real-time fluorescence quantitative PCR and Western blot. The effect of ANKRD49 on cell migration was measured by scratch test. The mRNA and protein levels of matrix metalloproteinase(MMP)-2/9 and tissue inhibitor of metalloproteinase(TIMP)-1/2 were detected by real-time fluorescence quantitative PCR and Western blot. The protein expression levels of p65,p-p65,IκBα and p-IκBα were detected by Western blot.Results The levels of ANKRD49 mRNA and protein in the ANKRD49 overexpression group were significantly higher than those in the control group(t = 70. 02 and 45. 68,respectively,each P < 0. 001). Compared with the control group,the migration ability of cells in the ANKRD49 overexpression group significantly increased at 24 h and 48 h(t = 5. 343 and 3. 282,P = 0. 005 9 and 0. 030 4,respectively);The mRNA transcription levels and protein expression levels of MMP-2 and MMP-9 significantly increased(t = 9. 304 and 6. 193,P =0. 000 7 and 0. 003 5,respectively),while the mRNA and protein expression of TIMP-1 and TIMP-2 decreased significantly(t = 3. 858 and 3. 517,P = 0. 018 2 and 0. 024 5,respectively),and the values of MMP-2/TIMP-1 and MMP-9/TIMP-2 significantly increased(t = 17. 7 and 9. 682,P < 0. 001 and < 0. 01,respectively);The expression of p-p65 and pIκBα significantly increased,the total protein levels of p65 and IκBα showed no obvious change,and the values of p-p65/p65 and p-IκBα/IκBα significantly increased(t = 3. 962 and 5. 370,P = 0. 016 7 and 0. 005 8,respectively). However,knocking down of ANKRD49 presented the opposite results.Conclusion ANKRD49 promotes the migration of NCI-H1299cells by enhan-cing the expression of MMP-2/9,the values of MMP-9/TIMP-1 and MMP-2/TIMP-2 via activating NF-κB/p65 signa-ling pathway.

From the Analysis of Anatomy and Locomotor Function of Biological Foot Systems to the Design of Bionic Foot: An Example of the Webbed Foot of the Mallard.

This study utilized the mallard's foot as the subject, examining the bone distribution via computed tomography (CT) and analyzing pertinent parameters of the tarsometatarsal bones. Additionally, gross anatomy methods were employed to elucidate the characteristics of the toes and webbing bio-structures and their material composition. Biologically, the mallard's foot comprises tarsometatarsal bones and 10 phalanges, enveloped by fascia, tendons, and skin. Vernier calipers were used to measure the bones, followed by statistical analysis to acquire structural data. Tendons, originating in proximal muscles and terminating in distal bones beneath the fascia, facilitate force transmission and systematic movement of each segment's bones. Regarding material composition, the skin layer serves both encapsulation and wrapping functions. Fat pads, located on the metatarsal side of metatarsophalangeal joints and each phalanx, function as cushioning shock absorbers. The correlation between the force applied to the tarsometatarsal bones and the webbing opening angle was explored using a texture analyzer. A simplified model describing the driving force behind the webbing opening angle was introduced. Furthermore, we designed a bionic foot, contributing a foundational reference for anti-sinking bionic foot development.

ANKRD49 promotes the metastasis of NSCLC via activating JNK-ATF2/c-Jun-MMP-2/9 axis.

BACKGROUND: Ankyrin repeat domain 49 (ANKRD49) has been found to be highly expressed in multiple cancer including lung adenocarcinoma (LUAD) and lung squamous carcinoma (LUSC). However, the function of ANKRD49 in the pathogenesis of NSCLC still remains elusive. Previously, ANKRD49 has been demonstrated to promote the invasion and metastasis of A549 cells, a LUAD cell line, via activating the p38-ATF-2-MMP2/MMP9 pathways. Considering the heterogeneity of tumor cells, the function and mechanism of ANKRD49 in NSCLC need more NSCLC-originated cells to clarify. METHODS: Real-time qPCR was employed to test ANKRD49 expression levels in nine pairs of fresh NSCLC tissues and the corresponding adjacent normal tissues. The function of ANKRD49 was investigated using overexpression and RNA interference assays in lung adenocarcinoma cell line (NCI-H1299) and lung squamous carcinoma cell line (NCI-H1703) through gelatin zymography, cell counting kit-8, colony formation, wound healing, migration and invasion assays mmunoprecipitation was performed to in vitro. Immunoprecipitation was performed to test the interaction of c-Jun and ATF2. Chromatin immunoprecipitation was conducted to assess the transcriptional regulation of ATF2/c-Jun on MMP-2/9. Moreover, the tumorigenicity of ANKRD49 was evaluated in nude mice models and the involved signal molecular was also measured by immunohistochemical method. RESULTS: We found that the levels of ANKRD49 in cancerous tissues were higher than those in adjacent normal tissues. in vitro assay showed that ANKRD49 promoted the migration and invasion of NCI-H1299 and NCI-H1703 cells via enhancing the levels of MMP-2 and MMP-9. Furthermore, ANKRD49 elevated phosphorylation of JNK and then activated c-Jun and ATF2 which interact in nucleus to promote the binding of ATF2:c-Jun with the promoter MMP-2 or MMP-9. In vivo assay showed that ANKRD49 promoted lung metastasis of injected-NSCLC cells and the high metastatic rate was positively correlated with the high expression of ANKRD49, MMP-2, MMP-9, p-JNK, p-c-Jun and p-ATF2. CONCLUSION: The present study indicated that ANKRD49 accelerated the invasion and metastasis of NSCLC cells via JNK-mediated transcription activation of c-Jun and ATF2 which regulated the expression of MMP-2/MMP-9. The molecular mechanisms of ANKRD49's function is different from those found in A549 cells. The current study is a supplement and improvement to the previous research.

Large-scale genomic survey and characterization of mcr genes carried by foodborne Cronobacter isolates.

IMPORTANCE: Cronobacter is an emerging foodborne opportunistic pathogen, which can cause neonatal meningitis, bacteremia, and NEC by contaminating food. However, the entire picture of foodborne Cronobacter carriage of the mcr genes is not known. Here, we investigated the mcr genes of Cronobacter isolates by whole-genome sequencing and found 133 previously undescribed Cronobacter isolates carrying mcr genes. Further genomic analysis revealed that these mcr genes mainly belonged to the mcr-9 and mcr-10. Genomic analysis of the flanking structures of mcr genes revealed that two core flanking structures were prevalent in foodborne Cronobacter isolates, and the flanking structure carrying IS1R was found for the first time in this study.

Effects of particle size and thickness of quartz sand on the webbed foot kinematics of mallard (Anas platyrhynchos).

The webbed foot structure of mallards (Anas platyrhynchos) exhibits effective anti-subsidence properties when walking on soft ground. To investigate the effects of quartz sand particle size and thickness on joint angles and the movement patterns of webbed feet, we created a testing substrate with quartz sand and utilized high-speed cameras and kinematic analysis tools for data acquisition. Mallards mainly adjusted the tarsometatarso-phalangeal joint (TMTPJ) during touch-down and lift-off stages in response to increasing particle size or enhanced ground roughness. Conversely, adjustments to the intertarsal joint (ITJ) predominantly took place during mid-stance. Conversely, mallards predominantly adjusted the ITJ during touch-down and lift-off when coping with increased quartz sand thickness, with TMTPJ adjustments mainly occurring at touch-down. As quartz sand particle size increased, the TMTPJ angle increased, the ITJ angle decreased, toe closure advanced, and the duty factor decreased throughout the entire stride cycle. In contrast, increasing quartz sand thickness led to more delayed TMTPJ adjustments, slower webbed foot closure, and an increased duty factor throughout the stride cycle. Mallards modify their leg posture to notably decrease the touch-down foot angle upon encountering sandy terrain. This action subsequently forms a depression beneath their feet, contributing to sand consolidation and limiting flow. During the stance phase, the mallard's weight is distributed across the webbed foot, generating minimal pressure and preventing significant subsidence while walking on sandy ground.

The size of the susceptible pool differentiates climate effects on seasonal epidemics of bacillary dysentery.

OBJECTIVES: At present, some studies have pointed out several possible climate drivers of bacillary dysentery. However, there is a complex nonlinear interaction between climate drivers and susceptible population in the spread of diseases, which makes it challenging to detect climate drivers at the size of susceptible population. METHODS: By using empirical dynamic modeling (EDM), the climate drivers of bacillary dysentery dynamic were explored in China's five temperature zones. RESULTS: We verified the availability of climate drivers and susceptible population size on bacillary dysentery, and used this information for bacillary dysentery dynamic prediction. Moreover, we found that their respective effects increased with the increase of temperature and relative humidity, and their states (temperature and relative humidity) were different when they reached their maximum effects, and the negative effect between the effect of temperature and disease incidence increased with the change of temperature zone (from temperate zone to warm temperate zone to subtropical zone) and the climate driving effect of the temperate zone (warm temperate zone) was greater than that of the colder (temperate zone) and warmer (subtropics) zones. When we viewed from single temperature zone, the climatic effect arose only when the size of the susceptible pool was large. CONCLUSIONS: These results provide empirical evidence that the climate factors on bacillary dysentery are nonlinear, complex but dependent on the size of susceptible populations and different climate scenarios.

Fancd2os Reduces Testosterone Production by Inhibiting Steroidogenic Enzymes and Promoting Cellular Apoptosis in Murine Testicular Leydig Cells.

BACKGRUOUND: It is well-established that serum testosterone in men decreases with age, yet the underlying mechanism of this change remains elusive. METHODS: The expression patterns of Fancd2 opposite-strand (Fancd2os) in BALB/c male mice and testicular tissue derived cell lines (GC-1, GC-2, TM3, and TM4) were assessed using real-time polymerase chain reaction (RT-PCR), Western blot and immunofluorescence. The Fancd2os-overexpressing or knockdown TM3 cells were constructed by infecting them with lentivirus particles and were used to evaluated the function of Fancd2os. The testosterone production was measured using enzyme linked immunosorbent assay (ELISA) and the steroidogenic enzymes such as steroidogenic acute regulatory protein (StAR), P450 cholesterol side-chain cleavage (P450scc), and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) were analysed using RT-PCR. The apoptosis of TM3 cells induced by ultraviolet light or testicular tissues was detected using flow cytometry, Western blot or dUTP-biotin nick end labeling (TUNEL) assays. Pearson correlation analysis was used to assess the correlation between the Fancd2os expression and TUNEL-positive staining in mouse testicular Leydig cells. RESULTS: The Fancd2os protein was predominantly expressed in mouse testicular Leydig cells and its expression increased with age. Fancd2os overexpression inhibited testosterone levels in TM3 Leydig cells, whereas knockdown of Fancd2os elevated testosterone production. Fancd2os overexpression downregulated the levels of StAR, P450scc and 3ß-HSD, while Fancd2os knockdown reversed this effect. Fancd2os overexpression promoted ultraviolet light-induced apoptosis of TM3 cells. In contrast, Fancd2os knockdown restrained apoptosis in TM3 cells. In vivo assays revealed that higher Fancd2os levels and mouse age were associated with increased apoptosis in Leydig cells and decreased serum testosterone levels. Pearson correlation analysis exhibited a strong positive correlation between the expression of Fancd2os and TUNEL-positive staining in mouse testicular Leydig cells. CONCLUSION: Our findings suggest that Fancd2os regulates testosterone synthesis via both steroidogenic enzymes and the apoptotic pathway.

Toxoplasma gondii ROP17 promotes autophagy via the Bcl-2-Beclin 1 pathway.

The apicomplexan Toxoplasma gondii (Nicolle et Manceaux, 1908) secretes a group of serine/threonine kinases from rhoptries, which play vital roles in boosting intracellular infection. Toxoplasma gondii rhoptry organelle protein 17 (ROP17) is one of these important kinase proteins. Nevertheless, its function remains unclear. Here, we showed that ROP17 induced autophagy in vitro and in vivo. The autophagy of small intestine tissues of T. gondii tachyzoite (RH strain)-infected mice was detected by the immunohistochemistry staining of LC3B, Beclin 1 and P62. ROP17 overexpression augmented starvation-induced autophagy in HEK 293T cells as measured by MDC staining, transmission electron microscopy (TEM), fluorescence microscopy and Western blot analysis. Moreover, the interaction of ROP17 and Bcl-2 was confirmed using co-immunoprecipitation analysis, and the data demonstrated that ROP17 had an autophagic role dependent on the Beclin 1-Bcl-2 pathway, which was also revealed in an in vivo model through immunohistochemical staining. Pearson coefficient analysis showed that there existed strong positive correlations between the expression of ROP17 and LC3B, Beclin 1 and phosphorylation of Bcl-2, while strong negative correlations between the expression of ROP17 and p62 and Bcl-2. Collectively, our findings indicate that ROP17 plays a pivotal role in maintaining T. gondii proliferation in host cells via the promotion of autophagy-dependent survival.

Genomic Epidemiology of an Outbreak of Klebsiella pneumoniae ST471 Producing Extended-Spectrum ß-Lactamases in a Neonatal Intensive Care Unit.

PURPOSE: Klebsiella pneumoniae producing extended-spectrum ß-lactamases (ESBLs) causes nosocomial infections worldwide. The present study aimed to determine the molecular subtyping characteristics and antibiotic resistance mechanisms of ESBL-producing K. pneumoniae strains collected during an outbreak. Moreover, we attempted to reveal the fine transmission route of the strains within this outbreak using whole-genome sequencing (WGS). METHODS: Collecting cases and strain information were carried out. Outbreak-related strains were identified using pulsed-field gel electrophoresis (PFGE). The antibiotic susceptibility, drug-resistant genes, and molecular subtype characteristics of ESBL-producing K. pneumoniae were analyzed. The fine transmission route of the strains within this outbreak was revealed using WGS and minimum core genome (MCG) sequence typing. RESULTS: In mid-January, 2015, five cases of neonatal pneumonia caused by ESBL-producing K. pneumoniae were observed in the neonatal intensive care unit (NICU) of the Affiliated Hospital of Chifeng University, China. Eight ESBL-producing K. pneumoniae were isolated from these five cases, and two additional strains from another two cases were identified using PFGE. All ten isolates harbored bla CTX-M-15, bla TEM-1, bla SHV-108, and bla OXA-1 genes, and belonged to the sequence type 471 (ST471) clone. A putative transmission map was constructed via comprehensive consideration of genomic and epidemiological information. WGS identified the initial case and the "superspreader". The genomic epidemiological investigation revealed that the outbreak was caused by the introduction of the bacteria one month before the first case appeared. CONCLUSION: As far as we know, this is the first report to describe the characteristics of an ST471 ESBL-producing K. pneumoniae outbreak. The data showed that epidemiological inferences could be greatly improved by interpretation in the context of WGS and that K. pneumoniae strains isolated from the same outbreak contain sufficient genomic differences to refine epidemiological linkages on the basis of genetic lineage. These findings suggested that integration of genomic and epidemiological data can help us to have a clearer understanding of when and how outbreaks occur, so as to better control nosocomial transmission.

Surface-Displayed Thermostable Candida rugosa Lipase 1 for Docosahexaenoic Acid Enrichment.

Yeast surface display has emerged as a viable approach for self-immobilization enzyme as whole-cell catalysts. Herein, we displayed Candida rugosa lipase 1 (CRL LIP1) on the cell wall of Pichia pastoris for docosahexaenoic acid (DHA) enrichment in algae oil. After a 96-h culture, the displayed CRL LIP1 achieved the highest activity (380 ± 2.8 U/g) for hydrolyzing olive oil under optimal pH (7.5) and temperature (45 °C) conditions. Additionally, we improved the thermal stability of displayed LIP1, enabling retention of 50% of its initial bioactivity following 6 h of incubation at 45 °C. Furthermore, the content of DHA enhanced from 40.61% in original algae oil to 50.44% in glyceride, resulting in a 1.24-fold increase in yield. The displayed CRL LIP1 exhibited an improved thermal stability and a high degree of bioactivity toward its native macromolecule substrates algae oil and olive oil, thereby expanding its potential for industrial applications in fields of food and pharmaceutical. These results suggested that surface display provides an effective strategy for simultaneous convenient expression and target protein immobilization.

Identification and Characterization of Cronobacter Strains Isolated from Environmental Samples.

As an emerging food-borne pathogen, Cronobacter species are ubiquitous in the food and environment. In order to know the characteristics of Cronobacter spp. from the environment, we isolated Cronobacter spp. from soil and water, and then studied the molecular typing and antibiotic resistance characteristics of these isolates. In 2016, 141 soil and water samples were collected from farms and Riverside Park in Beijing. Isolates were identified by real-time PCR, 16s rRNA sequencing, and whole-genome sequencing. Molecular subtyping of these isolates was characterized by pulsed-field gel electrophoresis, multilocus sequence typing (MLST), and antibiotic susceptibility tests. Cronobacter species were classified based on fusA sequencing. Twenty-two samples (15.60%) contained Cronobacter spp., and four species were detected, i.e., C. dubliniensis (n = 10), C. sakazakii (n = 6), C. turicensis (n = 4), and C. malonaticus (n = 2). For MLST, 12 types (ST519-ST525, ST533-ST537) were newly identified, indicating high diversity. Most isolates (68.18%) showed resistance to cefazolin. Siccibacter turicensis and Cronobacter both with blue-green colonies on selective media should be respectively identified. Apparently, major Cronobacter species in soil and water samples differed from those in food. Molecular subtyping showed that the environment could not be excluded as a source of Cronobacter infection. The resistance to cefazolin of most isolates indicated natural resistance.

A novel inducible acute hyperglycemia mouse model for assessing 6-KTP.

The aim of the present study was to establish a mouse model of acute hyperglycemia, which may be utilized to detect the glucose concentration-dependent hypoglycemic activity of the glucagon-like peptide-1 derivative, 6-KTP. The results demonstrated that the first 30 min following the intraperitoneal injection of 2 g/kg glucose into C57BL/6J mice was the optimum time for assessing the hypoglycemic activity of potential therapeutic methods for diabetes. There was a linear association between the dose of 6-KTP and hypoglycemic activity between 0.2 and 1.2 mg/kg. The resulting model may serve as template for developing cost-effective in vivo models to test similar therapeutics.

Genomic Analysis of Putative Virulence Factors Affecting Cytotoxicity of Cronobacter.

Cronobacter spp. can cause systemic infections, such as meningitis, sepsis, and necrotizing enterocolitis, in immunocompromised patients, especially neonates. Although some virulence factors have been reported previously, the pathogenesis of Cronobacter remains unclear. In this study, we compared genome sequences from different Cronobacter species, sequence types, and sources, with the virulence genes in the virulence factor database. The results showed that Cronobacter has species specificity for these virulence genes. Additionally, two gene clusters, including sfp encoding fimbriae and hly encoding hemolysin, were discovered. Through cell adhesion, cytotoxicity, and hemolysis assays, we found that the isolates possessing the two gene clusters had higher cytotoxicity and stronger hemolysis capacity than those of other isolates in this study. Moreover, analysis of type VI secretion system (T6SS) cluster and putative fimbria gene clusters of Cronobacter revealed that T6SS have species specificity and isolates with high cytotoxicity possessed more complete T6SS cluster construction than that of the rest. In conclusion, the two novel gene clusters and T6SS cluster were involved in the mechanism underlying the cytotoxicity of Cronobacter.

Contamination of Cronobacter spp. in Chinese Retail Spices.

Crononbacter spp. is an opportunistic foodborne pathogen that causes infections in neonates, infants, and immunocompromised adults. Although the contamination of spices with Cronobacter has been previously reported in some countries, there have been no studies on Cronobacter contamination in China. Therefore, this study aimed to investigate the prevalence of Cronobacter spp. in Chinese retail spices. Fifty-six packaged Chinese spices were collected from different markets, and 32 of these were found to be contaminated with Cronobacter. Five species were identified from the 54 isolates of the 32 positive samples: Cronobacter sakazakii (n = 35), Cronobacter muytjensii (n = 8), Cronobacter malonaticus (n = 6), Cronobacter turicensis (n = 3), and Cronobacter dublinensis (n = 2). Pulsed-field gel electrophoresis demonstrated high genetic diversity, as 53 PFGE profiles were revealed for the 54 isolates. Multilocus sequence typing analysis revealed 46 sequence types, and of these, 26 were newly identified. Most of the isolates were sensitive to antibiotics (n = 15), with the exception of cefazolin. This study revealed that the contamination of Chinese retail spices by Cronobacter spp. poses a potential risk to the consumer.