Enzymatically Cyclic Activated Biosensor Based on a Tetrahedral DNA Framework for Precise Tumor in Situ Molecular Imaging.

The development of stimulus-responsive and amplification-based strategies is crucial for achieving improved spatial specificity and enhanced sensitivity in tumor molecular imaging, addressing challenges such as off-tumor signal leakage and limited biomarker content. Therefore, a cyclically activated enzymatic biosensor based on the modification of an AP site within a tetrahedral framework DNA (AP-tFNA) was rationally developed for tumor cell-specific molecular imaging using the endogenous enzyme apurinic/apyrimidinic endonuclease 1 (APE1) as a target, exhibiting superior spatial specificity and high sensitivity. APE1, which predominantly localizes within the nucleus in normal cells but exhibits cytosolic and nucleus expression in cancer cells, can specifically recognize and cleave the AP site in AP-tFNA, resulting in the separation of the fluorophore and quenching group, thereby inducing a fluorescence signal. Additionally, upon completion of the excision of one AP site in AP-tFNA, APE1 is released, thereby initiating a subsequent cycle of hydrolytic cleavage reactions. The experimental results demonstrated that AP-tFNA enables precise differentiation of tumor cells both in vitro and in vivo. In particular, the AP-tFNA can monitor drug resistance in neuroblastoma cells and classify the risk for neuroblastoma patients at the clinical plasma level.

Epidemiology, microbiology and antibiotic treatment of bacterial and fungal meningitis among very preterm infants in China: a cross-sectional study.

OBJECTIVE: Neonatal meningitis significantly contributes to neonatal morbidity and mortality, yet large-scale epidemiological data in developing countries, particularly among very preterm infants (VPIs), remain sparse. This study aimed to describe the epidemiology of meningitis among VPIs in China. DESIGN: Cross-sectional study using the Chinese Neonatal Network database from 2019 to 2021. SETTING: 79 tertiary neonatal intensive care units in China. PATIENTS: Infants with gestational age <32 weeks or birth weight <1500 g. MAIN OUTCOME MEASURES: Incidence, pathogen distribution, antimicrobial use and outcomes of bacterial and fungal meningitis. RESULTS: Of 31 915 VPIs admitted, 122 (0.38%) infants were diagnosed with culture-confirmed meningitis, with 14 (11.5%) being early-onset (≤6 days of age) and 108 (88.5%) being late-onset (>6 days of age). The overall in-hospital mortality was 18.0% (22/122). A total of 127 pathogens were identified, among which 63.8% (81/127) were Gram-negative bacteria, 24.4% (31/127) were Gram-positive bacteria and 11.8% (15/127) were fungi. In terms of empirical therapy (on the day of the first lumbar puncture), the most commonly used antibiotic was meropenem (54.9%, 67/122). For definitive therapy (on the sixth day following the first lumbar puncture, 86 cases with available antibiotic data), meropenem (60.3%, 35/58) and vancomycin (57.1%, 16/28) were the most used antibiotics for Gram-negative and Gram-positive bacterial meningitis, respectively. 44% of infants with Gram-positive bacterial meningitis and 52% with Gram-negative bacterial meningitis received antibiotics for more than 3 weeks. CONCLUSION: 0.38% of VPIs in Chinese neonatal intensive care units were diagnosed with meningitis, experiencing significant mortality and inappropriate antibiotic therapy. Gram-negative bacteria were the predominant pathogens, with fungi emerging as a significant cause.

Clinical characteristics of neonatal and infant osteomyelitis and septic arthritis: a multicenter retrospective study

Abstract Objective: Signs and symptoms of osteomyelitis or septic arthritis in neonates and infants are often nonspecific and early-stage bone infections in infants may often go unnoticed. The objective of this study was to analyze the clinical characteristics of newborns and infants with osteomyelitis and septic arthritis to improve understanding of the disorder and to assist clinicians with diagnosis. Methods: A retrospective multicenter study was conducted on neonates (0-28 days old, n = 94) and infants (1-12 months old, n = 415) with osteoarticular infections. Data consisting of clinical characteristics, complications, laboratory outcomes, and the pathogenic microorganisms causing osteomyelitis were tabulated. The statistics were further broken down into two regions and the significant differences between neonates and infants were evaluated and compared to the literature. Results: Compared to infants, neonates had significantly lower incidences of fever (p < 0.0001), higher incidences of localized swelling (p = 0.0021), higher rate of infection at the humerus (p = 0.0016), higher percentage of Escherichia coli (p < 0.0001) and Klebsiella pneumoniae (p = 0.0039) infections, lower percentage of Staphylococcus aureus infections (p < 0.0001) and were more likely to develop septic arthritis (p < 0.0001). Conclusion: Distinct differences were found between neonatal and infants with osteoarticular infections. Future studies should focus on improving diagnosis and subsequent treatment regimens for younger age groups.

Gastroprotective effects of polysaccharides from purple sweet potato (Ipomoea batatas (L.) Lam) on an ethanol-induced gastric ulcer via regulating immunity and activating the PI3K/Akt/Rheb/mTOR pathway.

The study aimed to investigate the alleviation of an ethanol-induced gastric ulcer in mice by apolysaccharide (PSP) from purple sweet potato (Ipomoea batatas (L.) Lam) and explore the mechanism. The anti-ulcer activity was determined by histopathological evaluation, total gastric acidity, pepsin activity, gastric ulcer index and gastric ulcer inhibition rate. The expression levels of inflammatory factors were detected using ELISA. A special protein meter was used to detect the content of immunoglobulin lgM, immunoglobulin lgG, and complements C3 and C4 in the serum of mice. The expression of CD4+/CD8+ lymphocyte subsets of mice was detected using flow cytometry. Western blot analysis was used to examine the effect of PSP on the PI3K/Akt/Rheb/mTOR pathway. The results showed that PSP could effectively reduce the total gastric acidity, pepsin activity, and the index and inhibition rate of gastric ulcers. At the same time, PSP could significantly increase the levels of immunoglobulins (lgG and lgM) and complements (C3 and C4). It could also increase the activity of peritoneal macrophages in mice and the expression of CD4+/CD8+ in the spleen. ELISA analysis showed that the contents of TNF-α, IL-1ß and IL-6 were significantly decreased and the content of IL-10 was significantly increased in the PSP group. The western blot analysis showed that PSP could upregulate the relative protein expressions of MUC5AC, PI3K, p-Akt, Rheb and mTOR. These results indicate that PSP can activate the PI3K/Akt/Rheb/mTOR signaling pathway to improve the immunity of mice and maintain the balance of the immune system, thereby protecting the gastric mucosa and improving stress gastric ulcers.

Clinical characteristics of neonatal and infant osteomyelitis and septic arthritis: a multicenter retrospective study.

OBJECTIVE: Signs and symptoms of osteomyelitis or septic arthritis in neonates and infants are often nonspecific and early-stage bone infections in infants may often go unnoticed. The objective of this study was to analyze the clinical characteristics of newborns and infants with osteomyelitis and septic arthritis to improve understanding of the disorder and to assist clinicians with diagnosis. METHODS: A retrospective multicenter study was conducted on neonates (0-28 days old, n = 94) and infants (1-12 months old, n = 415) with osteoarticular infections. Data consisting of clinical characteristics, complications, laboratory outcomes, and the pathogenic microorganisms causing osteomyelitis were tabulated. The statistics were further broken down into two regions and the significant differences between neonates and infants were evaluated and compared to the literature. RESULTS: Compared to infants, neonates had significantly lower incidences of fever (p < 0.0001), higher incidences of localized swelling (p = 0.0021), higher rate of infection at the humerus (p = 0.0016), higher percentage of Escherichia coli (p < 0.0001) and Klebsiella pneumoniae (p = 0.0039) infections, lower percentage of Staphylococcus aureus infections (p < 0.0001) and were more likely to develop septic arthritis (p < 0.0001). CONCLUSION: Distinct differences were found between neonatal and infants with osteoarticular infections. Future studies should focus on improving diagnosis and subsequent treatment regimens for younger age groups.

Optimization of Extraction Process and Activity of Angiotensin-Converting Enzyme (ACE) Inhibitory Peptide from Walnut Meal.

In order to further realize the resource reuse of walnut meal after oil extraction, walnut meal was used as raw material to prepare polypeptide, and its angiotensin-converting enzyme (ACE) inhibitory activity was investigated. The ACE inhibitory peptides were prepared from walnut meal protein by alkaline solution and acid precipitation. The hydrolysis degree and ACE inhibition rate were used as indexes to optimize the preparation process by single-factor experiment and response surface method. The components with the highest ACE activity were screened by ultrafiltration, and their antioxidant activities were evaluated in vitro. The effect of gastrointestinal digestion on the stability of walnut peptide was analyzed by measuring molecular weight and ACE inhibition rate. The results showed that the optimal extraction conditions were pH 9.10, hydrolysis temperature 54.50 °C, and hydrolysis time 136 min. The ACE inhibition rate of walnut meal hydrolysate (WMH) prepared under these conditions was 63.93% ± 0.43%. Under the above conditions, the fraction less than 3 kDa showed the highest ACE inhibitory activity among the ACE inhibitory peptides separated by ultrafiltration. The IC50 value of scavenging ·OH free radical was 1.156 mg/mL, the IC50 value of scavenging DPPH free radical was 0.25 mg/mL, and the IC50 value of scavenging O2- was 3.026 mg/mL, showing a strong total reducing ability. After simulated gastrointestinal digestion in vitro, the ACE inhibitory rate of walnut peptide decreased significantly, but it still maintained over 90% ACE inhibitory activity. This study provides a reference for the application of low-molecular-weight walnut peptide as a potential antioxidant and ACE inhibitor.

Relationship between biofilm formation and antibiotic resistance of Klebsiella pneumoniae and updates on antibiofilm therapeutic strategies.

Klebsiella pneumoniae is a Gram-negative bacterium within the Enterobacteriaceae family that can cause multiple systemic infections, such as respiratory, blood, liver abscesses and urinary systems. Antibiotic resistance is a global health threat and K. pneumoniae warrants special attention due to its resistance to most modern day antibiotics. Biofilm formation is a critical obstruction that enhances the antibiotic resistance of K. pneumoniae. However, knowledge on the molecular mechanisms of biofilm formation and its relation with antibiotic resistance in K. pneumoniae is limited. Understanding the molecular mechanisms of biofilm formation and its correlation with antibiotic resistance is crucial for providing insight for the design of new drugs to control and treat biofilm-related infections. In this review, we summarize recent advances in genes contributing to the biofilm formation of K. pneumoniae, new progress on the relationship between biofilm formation and antibiotic resistance, and new therapeutic strategies targeting biofilms. Finally, we discuss future research directions that target biofilm formation and antibiotic resistance of this priority pathogen.

Function and therapeutic prospects of next-generation probiotic Akkermansia muciniphila in infectious diseases.

Akkermansia muciniphila is a gram-negative bacterium that colonizes the human gut, making up 3-5% of the human microbiome. A. muciniphila is a promising next-generation probiotic with clinical application prospects. Emerging studies have reported various beneficial effects of A. muciniphila including anti-cancer, delaying aging, reducing inflammation, improving immune function, regulating nervous system function, whereas knowledge on its roles and mechanism in infectious disease is currently unclear. In this review, we summarized the basic characteristics, genome and phenotype diversity, the influence of A. muciniphila and its derived components on infectious diseases, such as sepsis, virus infection, enteric infection, periodontitis and foodborne pathogen induced infections. We also provided updates on mechanisms how A. muciniphila protects intestinal barrier integrity and modulate host immune response. In summary, we believe that A. muciniphila is a promising therapeutic probiotic that may be applied for the treatment of a variety of infectious diseases.

The impact of blood lactic acid levels on retinopathy of prematurity morbidity.

BACKGROUND: Retinopathy of prematurity (ROP) is a common disease in premature infants. In recent years, most researchers have used lactic acid as poor prognosis marker in premature infants. This study aims to explore investigate the impact of blood lactic acid levels on ROP. METHODS: A retrospective case-control study was conducted, and infants with severe ROP born with birth weight (BW) ≤ 1500 g and gestational age (GA) ≤ 32 weeks were enrolled from November 2016 to November 2021. Infants without any stage ROP were included as controls and were matched with ROP infants (1:2) by GA and BW. All selected preterm infants were tested for heel terminal trace blood gas analysis within two weeks of life. Changes in blood lactic acid levels in the two groups were compared and analyzed by using multivariate logistic regression analysis. Sensitivity and specificity were analyzed by receiver operating characteristic (ROC) curve. RESULTS: There were 79 infants in ROP group, and 158 infants in control group. The levels of blood lactic acid were significantly higher in the ROP group on days 1, 3, 5, and 7 compared with control group (all p < 0.05). The blood lactic acid levels on day 5 was an independent risk factor for ROP (p = 0.017). The area under the curve (AUC), sensitivity and specificity were highest on day 5 (AUC 0.716, sensitivity 77.2% and specificity 62.0%, respectively, p < 0.001), and higher on days 1, 3, and 7. CONCLUSION: A high blood lactic acid level in the first seven days of life may be associated with increases ROP occurrence in very preterm infants, and suggest blood lactic acid level may impact the occurrence of ROP.

XJB-5-131 protects chondrocytes from ferroptosis to alleviate osteoarthritis progression via restoring Pebp1 expression.

Background: Osteoarthritis (OA) is the most common age-related musculoskeletal disease. However, there is still a lack of therapy that can modify OA progression due to the complex pathogenic mechanisms. The aim of the study was to explore the role and mechanism of XJB-5-131 inhibiting chondrocytes ferroptosis to alleviate OA progression. Methods: We treated tert-butyl hydroperoxide (TBHP)-induced ferroptosis of mouse primary chondrocytes with XJB-5-131 in vitro. The intracellular ferroptotic hallmarks, cartilage anabolic and catabolic markers, ferroptosis regulatory genes and proteins were detected. Then we established a mouse OA model via destabilization of the medial meniscus (DMM) surgery. The OA mice were treated with intra-articular injection of XJB-5-131 regularly (2 µM, 3 times per week). After 4 and 8 weeks, we performed micro-CT and histological examination to evaluate the protection role of XJB-5-131 in mouse OA subjects. RNA sequencing analysis was performed to unveil the key downstream gene of XJB-5-131 exerting the anti-ferroptotic effect in OA. Results: XJB-5-131 significantly suppressed TBHP-induced increases of ferroptotic hallmarks (ROS, lipid peroxidation, and Fe2+ accumulation), ferroptotic drivers (Ptgs2, Pgd, Tfrc, Atf3, Cdo1), while restored the expression of ferroptotic suppressors (Gpx4, Fth1). XJB-5-131 evidently promoted the expression of cartilage anabolic and decreased the expression of cartilage catabolic markers. Moreover, intra-articular injection of XJB-5-131 significantly inhibited the expression of Cox2 and Mmp13, while promoted the expression of Col2a1, Gpx4 and Fth1 in DMM-induced mouse articular cartilage. Further, we identified Pebp1 as a potential target of XJB-5-131 by RNA sequencing analysis. The anti-ferroptosis and chondroprotective effects of XJB-5-131 were significantly diminished by Locostatin, a specific antagonist of Pebp1. Conclusion: XJB-5-131 significantly protects chondrocytes from ferroptosis in TBHP-induced mouse primary chondrocytes and DMM surgery-induced OA mice model via restoring the expression of Pebp1. XJB-5-131 is a potential therapeutic drug in the management of OA progression.

The epidemiology and the pathogen distribution of pediatric dacryocystitis in Chinese population 2017-2022.

BACKGROUND: Dacryocystitis is a common disease in pediatric ophthalmology. Analysis of basic information, flora distribution, and characteristics of information on drug-resistant bacteria in children with dacryocystitis for 6 years, providing evidence for ophthalmologic infection prevention and clinical management strategies. METHODS: A retrospective cohort study was conducted to evaluate the demographics of dacryocystitis in children and microbiological characteristics of secretion cultures, and to analyze the basic information, distribution of pathogenic bacteria, drug resistance, and to plot trendsand distribution pie charts according to the years. RESULTS: This study recruited 5791 specimens. Decreased incidence of dacryocystitis from 2020 to 2022 (including the COVID-19 pandemic). The age of highest incidence of dacryocystitis is infancy, followed by the neonatal period, and the incidence decreased with age. Streptococcus pneumoniae had the highest percentage in 2017, and the overall trend was decreasing, the difference was statistically significant (p < 0.001); Streptococcus mitis showed an overall increasing trend, with the highest incidence in 2022 and the lowest in 2017, with a statistically significant difference (p < 0.001); Haemophilus influenzae was the most common gram-negative bacteria with an overall decreasing trend (p < 0.001); The incidence of Catamoeba and Stenotrophomonas varied from year to year, with statistically significant differences (p = 0.010, p = 0.033, respectively). Methicillin-resistant Staphylococcus aureus (MRSA) had the lowest incidence in 2017 and 2022 the highest incidence in 2022, with a statistically significant difference in incidence between years (p = 0.003); ß-lactamase-positive was the most common type of resistance, and MRSA was the second, with statistically significant differences between years (p = 0.003, p < 0.001, respectively). Streptococcus pneumoniae is a common etiologic agent of dacryocystitis in all age groups. CONCLUSIONS: Dacryocystitis in children is significantly associated with age characteristics and infection-related pathogens, and infection prevention and control can help reduce the infection of related pathogens and the increase of new drug-resistant strains. Close monitoring of changes in pathogen distribution in ocular secretion cultures can help in early intervention and treatment of infectious dacryocystitis.

Trends in bronchopulmonary dysplasia and respiratory support among extremely preterm infants in China over a decade.

OBJECTIVE: Bronchopulmonary dysplasia (BPD) is one of the most serious complications affecting extremely preterm infants. We aimed to evaluate temporal trends in BPD and administration of respiratory support among extremely preterm infants in China over a decade. METHODS: This was a retrospective study using data from a multicenter database, which included infants born less than 28 weeks' gestation discharged from 68 tertiary neonatal care centers in China between 2010 and 2019. Changes in rates and severity of BPD, as well as modalities and duration of respiratory support, were evaluated. RESULTS: Among 4808 eligible infants with gestational age (GA) of 21+6/7  to 27+6/7 weeks and a mean (SD) birth weight of 980 (177) g, no significant change of median GA was found over time. Overall, 780 (16.2%) infants died before 36 weeks' postmenstrual age, 2415 (50.2%) were classified as having no BPD, 917 (19.1%) developed Grade 1 BPD, 578 (12.0%) developed Grade 2 BPD, and 118 (2.5%) developed Grade 3 BPD. The rate of BPD increased from 20.8% in 2010 to 40.7% in 2019 (aRR for trend, 1.081; 95% confidence interval, 1.062-1.099), especially for Grade 1 and Grade 2. Although survival to discharge improved over the decade, the overall survival without BPD did not change during the study period. The use of invasive mechanical ventilation (IMV) remained unchanged. However, the use of noninvasive ventilation (NIV) increased from 71.5% in 2010 to 89.8% in 2019. Moreover, the median duration of NIV increased over time, from 17.0 (4.8, 34.0) days in 2010 to 33.0 (21.0, 44.0) days in 2019, without significant change in the duration of IMV. CONCLUSIONS: Although survival increased over the decade and respiratory support practices changed significantly between 2010 and 2019 in China, with increased use and duration of NIV, there was an increased rate of BPD and survival without BPD has not improved.

Influence of COVID-19 pandemic on the epidemiology of Mycoplasma pneumoniae infections among hospitalized children in Henan, China.

Background: Increasing reports have indicated that non-pharmaceutical interventions to control the COVID-19 pandemic may also have an effect on the prevalence of other pathogens. Mycoplasma pneumoniae is an important atypical pathogen prevalent in children with high rates of macrolide resistance. The aim of this study was to investigate the epidemiological characteristics of M. pneumoniae infection in children before and during the COVID-19 pandemic. Methods: In this study, M. pneumoniae detection results were extracted from Henan Children's Hospital from 2018 to 2021. The epidemiological characteristics of pediatric M. pneumoniae infection were analyzed. Results: We found that the highest positive rate of M. pneumoniae infection was 11.00 % in 2018, 14.01 % in 2019, followed by 11.24 % in 2021 and 8.75 % in 2020 (p < 0.001). Most tested children had respiratory system manifestations, and pneumoniae was the most common diagnosis (53.23 %). An increase in the number of positive cases was observed with an increase in age, with a higher number of cases among children over 6 years old. No positive cases were identified among children aged 1-28 days. The decrease in the positive rate among children aged between1-6 years old in 2020 and 2021 was found to be statistically significant (p < 0.001). The pre-pandemic period demonstrated a higher incidence rate in the fall, whereas the summers and winters exhibited a significantly higher positive rate during the pandemic period (p < 0.001). Different regions in Henan also showed different epidemic patterns. Conclusions: In summary, strict pandemic measures influenced the spread of M. pneumoniae to some extent and changed demographic characteristics, including age, season and regional distribution. Continuous monitoring is required for the control and prevention of related diseases.

The effect of leucocytosis on retinopathy of prematurity.

Postnatal leukocytosis reflects the general condition of inflammatory. Infection and inflammatory reaction have been proven to affect the occurrence of ROP and other visual dysfunction. Infants with a gestational age of < 28 weeks who were less than three days of age and admitted to the hospital between September 2015 and March 2021 were included in the study. Infants with a white blood cell (WBC) count ≥ 30 × 109/L were assigned to the leucocytosis group (n = 82). Gestational age- and weight-matched infants without leucocytosis were included as a control group (n = 85). The incidence and prognosis of ROP in preterm infants were compared between the groups. Receiver operating characteristic (ROC) curves were used to analyse the correlation between the WBC count and severe ROP. Compared to the infants in the control group, those in the leucocytosis group had lower 1-min Apgar scores (p < 0.001); higher C-reactive protein (p < 0.001) and procalcitonin (p < 0.001); and higher incidences of intracranial haemorrhage (p = 0.007), leukomalacia (p = 0.045), sepsis (p = 0.006), bronchopulmonary dysplasia (p = 0.017). The maternal age was higher in the leucocytosis group (p < 0.001). After adjusting for gestational age at 45 weeks, the incidence of severe ROP (p = 0.001) and the requirement for ranibizumab injections (p = 0.004) were higher in the leucocytosis group. The cut-off WBC count was determined to be 19.1 × 109/L, with a sensitivity of 88.6%, a specificity of 77.3%, and an area under the curve of 0.941 (95% confidence interval: 0.904-0.978) for the detection of severe ROP. Leucocytosis may be associated with severe ROP in premature infants.

Clinical characteristics and long-term neurodevelopmental outcomes of leukomalacia in preterm infants and term infants: a cohort study.

BACKGROUND: Leukomalacia is a serious form of neonatal brain injury that often leads to neurodevelopmental impairment, and studies on neonatal leukomalacia and its long-term outcomes are lacking. The aim of this study was to analyze the clinical manifestations, imaging features, and long-term neurodevelopmental outcomes in preterm infants and term infants with leukomalacia. METHODS: Newborns diagnosed with leukomalacia by head magnetic resonance imaging (MRI) and who were admitted to intensive care units from January 2015 to June 2020 were enrolled. All infants were followed up to June 2022 (2-7 years old), and their neurodevelopmental outcomes were evaluated. The clinical data and long- term outcomes of preterm infants and term infants was analyzed by Chi-square tests. RESULTS: A total of 218 surviving infants with leukomalacia including 114 preterm infants and 104 term infants completed the follow-up. The major typesof leukomalacia on MRI were periventricular leukomalacia in the preterm group and subcortical cystic leukomalacia in the term group, respectively (χ2 = 55.166; p < 0.001). When followed up to 2-7 years old, the incidence of neurodevelopmental impairment in the preterm group and term group was not significantly different (χ2 = 0.917; p = 0.338). However, the incidence of cerebral palsy (CP) in the preterm group was significantly higher (χ2 = 4.896; p = 0.027), while the incidence of intellectual disability (ID) (χ2 = 9.445; p = 0.002), epilepsy (EP) (χ2 = 23.049; p < 0.001), and CP combined with ID andEP (χ2 = 4.122; p = 0.042) was significantly lower than that in the term group. CONCLUSIONS: Periventricular leukomalacia mainly occurred in preterm infants while subcortical cystic leukomalacia was commonly seen in term infants. Although the long-term neurodevelopmental outcomes of leukomalacia were both poor, preterm infants were more prone to CP, while term infants were more prone to ID, EP, and the combination of CP with ID and EP.

Roles of two-component regulatory systems in Klebsiella pneumoniae: Regulation of virulence, antibiotic resistance, and stress responses.

Klebsiella pneumoniae is an opportunistic pathogen belonging to the Enterobacteriaceae family, which is the leading cause of nosocomial infections. The emergence of hypervirulent and multi-drug resistant K. pneumoniae is a serious health threat. In the process of infection, K. pneumoniae needs to adapt to different environmental conditions, and the two-component regulatory system (TCS) composed of a sensor histidine kinase and response regulator is an important bacterial regulatory system in response to external stimuli. Understanding how K. pneumoniae perceives and responds to complex environmental stimuli provides insights into TCS regulation mechanisms and new targets for drug design. In this review, we analyzed the TCS composition and summarized the regulation mechanisms of TCSs, focusing on the regulation of genes involved in virulence, antibiotic resistance, and stress response. Collectively, these studies demonstrated that several TCSs play important roles in the regulation of virulence, antibiotic resistance and stress responses of K. pneumoniae. A single two-component regulatory system can participate in the regulation of several stress responses, and one stress response process may include several TCSs, forming a complex regulatory network. However, the function and regulation mechanism of some TCSs require further study. Hence, future research endeavors are required to enhance the understanding of TCS regulatory mechanisms and networks in K. pneumoniae, which is essential for the design of novel drugs targeting TCSs.

Structural characterization and induction of tumor cell apoptosis of polysaccharide from purple sweet potato (Ipomoea batatas (L.) Lam).

The carbohydrate is the main ingredient of purple sweet potato. A polysaccharide, named PSP, was separated and purified from purple sweet potato by extraction with hot water, precipitation with ethanol, deproteinization with Sevag reagent and column chromatography with Sephadex G-100. The purity and structure were studied with HPLC, UV-Vis, GC-MS and NMR. The PSP is a neutral polysaccharide with Mw of 470 kDa. The monosaccharide composition of PSP contained D-xylose, d-glucose, D-galactose with ratio of 1.0: 8.3: 1.3. The backbone of PSP was composed of the residues of →6)-D-Glcp-(1 â†’ and →2, 6)-D-Glcp-(1→. The branches of PSP contained the residues of →3)-D-Galp-(1→, and D-Xylp-(1→. The antitumor activity in vitro of PSP was analyzed with HT-29 cells. And the SEM, AO staining, MDC staining and hoechst 33342 staining were performed to study the effect on apoptosis of HT-29 cells by PSP. The results revealed that the PSP can significantly inhibit the proliferation of HT-29 cells from induction apoptosis. The manuscript provided valuable knowledges on structural characteristics of the polysaccharides from purple sweet potato.