Synergistic antimicrobial interaction of plant essential oils and extracts against foodborne pathogens.

Essential oils (EOs) and plant extracts have demonstrated inhibitory activity against a wide range of pathogenic bacteria. In this study, the chemical composition of manuka, kanuka, peppermint, thyme, lavender, and feijoa leaf and peel EOs and feijoa peel and leaf extracts were analyzed, and their antimicrobial activity against Escherichia coli, Salmonella enterica Typhimurium, Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes were determined. The results showed that the major compounds varied among different EOs and extracts, with menthol in peppermint EO, thymol and carvacrol in thyme EO, linalool in lavender EO, ß-caryophyllene in feijoa EO, and flavones in feijoa extract being the most prevalent. The study found that while EOs/extracts had antimicrobial activity alone, no individual EO/extract was highly effective against all tested species. Therefore, their combinations were tested to identify those that could broaden the spectrum of activity and act synergistically. The checkerboard method was applied to assess the possible synergism between the paired combinations of EOs/extract. The peppermint/thyme, peppermint/lavender, and peppermint/feijoa peel extract combinations exhibited a synergistic effect against E. coli and L. monocytogenes, with the peppermint/thyme and peppermint/feijoa peel extract combinations being the most effective against all five pathogens. Time-to-kill kinetics assays demonstrated that peppermint/thyme and peppermint/feijoa peel extract combinations achieved complete eradication of E. coli within 10-30 min and L. monocytogenes within 4-6 h. This study provides a promising approach to developing a natural alternative for food preservation using synergistic combinations of EOs/extracts, which could potentially reduce the required dosage and broaden their application in food products as natural preservatives.

A neural circuit from the dorsal CA3 to the dorsomedial hypothalamus mediates balance between risk exploration and defense.

An appropriate balance between explorative and defensive behavior is essential for the survival and reproduction of prey animals in risky environments. However, the neural circuit and mechanism that allow for such a balance remains poorly understood. Here, we use a semi-naturalistic predator threat test (PTT) to observe and quantify the defense-exploration balance, especially risk exploration behavior in mice. During the PTT, the activity of the putative dorsal CA3 glutamatergic neurons (dCA3Glu) is suppressed by predatory threat and risk exploration, whereas the neurons are activated during contextual exploration. Moreover, optogenetic excitation of these neurons induces a significant increase in risk exploration. A circuit, comprising the dorsal CA3, dorsal lateral septal, and dorsomedial hypothalamic (dCA3Glu-dLSGABA-DMH) areas, may be involved. Moreover, activation of the dCA3Glu-dLSGABA-DMH circuit promotes the switch from defense to risk exploration and suppresses threat-induced increase in arousal.

Bio-inspired zwitterionic polymeric chelating assembly for treatment of copper-induced cytotoxicity and hemolysis.

We developed a hemocompatible, bio-inspired, multivalent, polymeric-chelating assembly based on the poly(2-methacryloyloxyethyl phosphorylcholine)-b-poly(serinyl acrylate) (PMPC-b-PserA) zwitterionic diblock copolymer. Functional PMPC-b-PserA was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization to catch and encapsulate free copper ions (Cu2+) in a solution. PMPC with an identical polar group to phospholipids exhibits high hydrophilicity and fouling resistance against non-specific adsorption, and inertness to the metal ions. On the other hand, PserA with pendant groups of amino acids possesses a strong capability to react with Cu2+ by coordination interaction. Therefore, when PMPC-b-PserA was brought into contact with Cu2+, a hydrophobic core with multiple coordination "bridges" between polymers and Cu2+ was formed, leading to self-assembly of core-shell polymer-metal nanoparticles. As a result, free Cu2+ ions can be removed from the solution to prevent damage to cells and tissues. The synthesis and chemical structure of PMPC-b-PserA were characterized, and the formation of self-assembled polymer-Cu2+ nanoparticles and colloidal stability were analyzed. More importantly, the detoxification of PMPC-b-PserA in presence of Cu2+ with fibroblast cells was demonstrated by increased cell viability >80%. In addition, the hemolysis, which occurred due to disruption of RBC membranes by free Cu2+, was effectively suppressed by adding PMPC-b-PserA. The bio-inspired and biocompatible chelating agent of PMPC-b-PserA provides a new treatment approach to encapsulate and detoxify heavy metals in complex media for chelation therapy.

Targeted Photodynamic Treatment of Bacterial Biofilms Using Curcumin Encapsulated in Cells and Cell Wall Particles.

Efficient inactivation and removal of pathogenic biofilms in food and biomedical environments remain a significant challenge for food safety applications and medical facilities. This research aims to develop food-grade microcarriers for the targeted delivery of a photosensitizer, curcumin, and photodynamic inactivation of a model pathogenic bacterial biofilm. The microcarriers evaluated in this study include alive yeast cell carriers, deactivated yeast cell carriers, and yeast cell wall particles. The microcarriers were evaluated based on the encapsulation yield of a model photosensitizer (curcumin), binding of the microcarriers to biofilms, and inactivation of the bacteria in the biofilms. The results illustrate that the combination of binding affinity, encapsulation yield, and the intracellular composition of the microcarriers influenced the overall inactivation of bacteria in the biofilms. All of the selected compositions achieved more than 93% inactivation of the bacteria in the biofilm using the photodynamic treatment, and the yeast cell wall particles with curcumin achieved over 99% inactivation of the bacteria in the biofilm matrix. In addition, all of the selected compositions demonstrated significant potential to remove the biofilm from the plastic surface, suggesting the role of binding affinity of the microcarriers in removal of the biofilm from surfaces. Overall, this study developed biomaterial formulations for targeted photodynamic inactivation and potential removal of biofilms.

Treatment strategies of hospitalized patients with coronavirus disease-19.

With the outbreak of coronavirus disease-19 (COVID-19), Changsha faced an increasing burden of treating the Wuhan migrants and their infected patients. This study is a retrospective, single-center case series of the 238 consecutive hospitalized patients with confirmed COVID-19 at the First Hospital of Changsha city, China, from 01/21 to 02/14, 2020; the final date of follow-up was 02/27, 2020. Of 238 patients 43.7% visited Wuhan, 58.4% got in touch with Wuhan people, and 47.5% had contacted with diagnosed patients. 37.8% patients had family members infected. 190 cases had mild / general disease, and 48 cases had severe / critical disease. Compared to mild or general patients, more severe or critical patients visited Wuhan (59.6% vs 40.2%; P=0.02) and contacted with Wuhan people (74.5% vs 55.0%; P=0.02). All patients received antiviral treatment, including Lopinavir / Ritonavir (29.3%), Interferon (14.6%) and their combination (40.6%), Arbidol (6.7%), Xuebijing (7.1%) and Chloroquine phosphate (1.3%). Severe and critical patients received glucocorticoid, Gamma-globulin and oxygen inhalation. Some received mechanic ventilation support. As of 02/27, 161 patients discharged. The median length of hospital stay was 13 days. The 10-, 14-, 20- and 28-day discharge rate was 19.1%, 42.8%, 65.0% and 76.4%, respectively. No hospital-related transmission was observed.

[Effect of Xuebijing injection on inflammatory markers and disease outcome of coronavirus disease 2019].

OBJECTIVE: To observe the influence of Xuebijing injection on the inflammatory markers and prognosis of coronavirus disease 2019 (COVID-19) patients. METHODS: Sixty severe COVID-19 patients admitted to Changsha Public Health Treatment Center (North Hospital of the First Hospital of Changsha City) from January to March in 2020 were randomly divided into routine treatment group, Xuebijing 50 mL group and Xuebijing 100 mL group, with 20 cases in each group. The routine treatment group was treated according to the National Health Commission's guide for COVID-19. On the basis of conventional treatment, Xuebijing injection was injected by 50 mL twice a day for 7 days in Xuebijing 50 mL group, while by 100 mL twice a day for 7 days in Xuebijing 100 mL group. The blood routine test, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), acute physiology and chronic health evaluation II (APACHE II) score, 2019 novel coronavirus (2019-nCoV) nucleic acid test and disease classification of three groups before and 8 days after treatment were observed. RESULTS: (1) After treatment, the white blood cell count (WBC) and lymphocyte count (LYM) of three groups increased, meanwhile CRP and ESR decreased. Compared with routine treatment group, the WBC count of Xuebijing 100 mL group after treatment significantly increased (×109/L: 7.12±0.55 vs. 5.67±0.51, P < 0.05), and the levels of CRP and ESR in Xuebijing 50 mL and 100 mL groups significantly decreased [CRP (mg/L): 32.3±4.6, 28.0±6.2 vs. 37.3±5.9; ESR (mm/1 h): 45.9±5.7, 40.5±7.4 vs. 55.3±6.6, all P < 0.05]. Compared with Xuebijing 50 mL group, the increase of WBC, and the decrease of CRP and ESR were more significant in Xuebijing 100 mL group [WBC (×109/L): 7.12±0.55 vs. 5.82±0.49, CRP (mg/L): 28.0±6.2 vs. 32.3±4.6, ESR (mm/1 h): 40.5±7.4 vs. 45.9±5.7, all P < 0.05]. (2) After treatment, the APACHE II score of three groups decreased. In Xuebijing 100 mL group, the APACHE II score after treatment was significantly lower than those in routine treatment and Xuebijing 50 mL groups (12.3±1.5 vs. 16.5±1.6, 15.9±1.4, both P < 0.05). After treatment, the 2019-nCoV nucleic acid test in three groups partly turned negative, with 9 cases in routine treatment group, 8 cases in Xuebijing 50 mL group and 9 cases in Xuebijing 100 mL group, without significant difference (P > 0.05). The conditions of patients in the three groups were improved after treatment, among them, 8 cases in the routine treatment group were transformed into common type, 1 case into critical type; 9 cases and 12 cases of Xuebijing 50 mL group and 100 mL group were transformed into common type respectively. Xuebijing 100 mL group was improved more obviously than Xuebijing 50 mL group and routine treatment group (both P < 0.05). CONCLUSIONS: The Xuebijing injection can effectively improve the inflammatory markers and prognosis of severe COVID-19 patients.

Non-sticky and antimicrobial zwitterionic nanocomposite dressings for infected chronic wounds.

Zwitterionic poly(sulfobetaine acrylamide) (pSBAA)-based nanocomposite hydrogels impregnated with germicidal silver nanoparticles (AgNPs) were synthesized and implemented for the treatment of infected chronic wounds. The zwitterionic hydrogels exhibited excellent non-sticky properties and had reinforced mechanical properties by the addition of hectorite nanoclay and poly(ethylene glycol)dimethacrylate as physical and chemical crosslinkers, respectively. In addition, AgNPs were grown within the intercalated clay/polymer structure by in situ free radical reduction, as confirmed by UV-vis spectroscopy and transmission electron microscopy (TEM). The silver-containing pSBAA nanocomposite hydrogels (pSBAA/Ag) exhibited germicidal properties against Gram-positive S. epidermidis and Gram-negative P. aeruginosa. The zwitterionic hydrogels show higher water content than 2-hydroxyethyl methacrylate (pHEMA) hydrogels, owing to the strong hydration via ionic solvation. The negligible cytotoxicity of pSBAA/Ag hydrogels was assessed with human fibroblasts by the MTT assay. Moreover, the zwitterionic hydrogels demonstrated excellent resistance to the adsorption of bovine serum albumin (BSA). To evaluate the feasibility of the hydrogels for clinical application as wound dressings, we created infected diabetic rat models and compared with commercial wound dressings. The results show that pSBAA/Ag hydrogels did not adhere to the newly formed tissue, and were readily removed from the wounds after treatment for 3 days. Moreover, the healing recovery was evaluated by visual observation of infected dorsal wounds on rats with induction of diabetes by streptozotocin. The finding indicates complete healing with the pSBAA/Ag hydrogels after 15 days, faster than other dressings. A histological examination also proved that the zwitterionic hydrogels facilitated epithelialization and collagen distribution in the infected diabetic wounds. Consequently, these novel non-sticky and antimicrobial zwitterionic nanocomposite hydrogels can have high potential for the treatment of infected chronic wounds.

Neuroprotective effects of electroacupuncture on hypoxic-ischemic encephalopathy in newborn rats are associated with increased expression of GDNF-RET and protein kinase B.

OBJECTIVE: To explore the neuroprotective effects of electroacupuncture (EA) on hypoxic-ischemic encephalopathy (HIE) and to further investigate the role of glial cell line-derived neurotrophic factor (GDNF) family receptor member RET (rearranged during transfection) and its key downstream phosphatidylinositol 3 kinase (PI-3K)/protein kinase B (Akt) pathway in the process. METHODS: A total of 220 seven-day-old SD rats (of either sex, from 22 broods) were randomly divided into two groups, one (30 rats) for sham-surgery group and the other (190 rats) for HIE model group. The HIE model was established using the left common carotid artery ligation method in combination with hypoxic treatment. The successfully established rats were randomly divided into five groups, including control model group, EA group, sham-EA group, antagonist group and antagonist plus electroacupuncture group, with 35 rats in each group. Baihui (GV 20), Dazhui (GV 14), Quchi (LI 11) and Yongquan (KI 1) acupoints were chosen for acupuncture. EA was performed at Baihui and Quchi for 10 min once a day for continuous 1, 3, 7 and 21 days, respectively. The rats were then killed after the operation and injured cerebral cortex was taken for the measurement of neurologic damage by hematoxylin-eosin (HE) staining and the degenerative changes of cortical ultrastructure by transmission electron microscopy. RET mRNA level and Akt protein level were detected by real-time reverse-transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. RESULTS: EA could ameliorate neurologic damage of the first somatic sensory area (S1Tr) and alleviate the degenerative changes of ultrastructure of cortical neurons in rats subjected to HIE. And the longer acupuncture treatment lasted, the better its therapeutic effect would be. This was accompanied by gradually increased expression of GDNF family receptor RET at the mRNA level and its downstream signaling Akt at the protein level in the ischemic cortex. CONCLUSION: EA has neuroprotective effects on HIE and could be a potential therapeutic strategy for HIE in the neonate. Activation of RET/Akt signaling pathway might be involved in this process.

5-Caffeoylquinic acid decreases diet-induced obesity in rats by modulating PPARα and LXRα transcription.

BACKGROUND: Chlorogenic acids (CGAs) are widely distributed in plant material, including foods and beverages. 5-Caffeoylquinic acid (5-CQA) is the most studied CGA, but the mechanism of its hypolipidaemic effect remains unclear. This study aimed to determine the effect of 5-CQA on lipid metabolism in the liver of Sprague-Dawley rats fed a high-fat diet (HFD). RESULTS: 5-CQA suppressed HFD-induced increases in body weight and visceral fat-pad weight, serum lipid levels, and serum and hepatic free fatty acids in a dose-dependent manner. Real-time polymerase chain reaction revealed that 5-CQA altered the mRNA expression of the transcription factors peroxisome proliferator-activated receptor α (PPARα) and liver X receptor α (LXRα) and target genes involved in hepatic fatty acid uptake, ß-oxidation, fatty acid synthesis, and cholesterol synthesis. Moreover, hepatic tissue sections from HFD-fed rats showed many empty vacuoles, suggesting that liver cells were filled with more fat droplets. However, 5-CQA significantly ameliorated this effect. CONCLUSION: 5-CQA may improve lipid metabolism disorders by altering the expression of PPARα and LXRα, which are involved in multiple intracellular signalling pathways.

[Effect of electroacupuncture on expression of signal transducer and activator of transcription 3 in focal ischemic cerebral tissue in cerebral ischemia rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) intervention on expression of signal transducer and activator of transcription 3 (STAT 3) in the focal ischemic cerebral tissue, so as to study its mechanism underlying improving ischemic stroke. METHODS: A total of 150 SD rats were randomized into sham operation (control) group, cerebral ischemia (CI) model (model) group and EA group which were further randomly divided into 2 hour (2 h), 1 day (1 d), 3 d, 1 week (1 W) and 3 W subgroups (n = 6/subgroup for immunohistochemistry, n = 4/subgroup for Western blot). CI model was established by occlusion of the middle cerebral artery with electro-coagulation method. EA (3 Hz/20 Hz, 2-3 V) was applied to "Baihui" (GV 20) and "Dazhui "(GV 14) for 30 min. The expression of cerebral STAT 3 was detected by immunofluorescence histochemistry and laser-confocal microscopy, and Western blot, separately. RESULTS: Compared with the control group, cerebral STAT 3 immunofluorescence intensity values at the time-points of 2 h, 1 d, 3 d and 1 W, STAT 3 protein expression levels at the time-points of 2 h, 1 d and 3 d in the model group were increased significantly (P < 0.001, P < 0.05). After acupuncture intervention, cerebral STAT 3 immunofluorescence intensity values at the time-points of 1 d, 3 d, 1 W and 3 W, STAT 3 protein expression levels at the time-points of 1 d, 3 d and 3 W in the EA group were down-regulated considerably (P < 0.001, P < 0.01, P < 0.05). No significant differences were found between the control and model groups in STAT 3 immunofluorescence intensity at 3 W, and in STAT 3 protein expression levels at 1 W and 3 W, and between the EA and model groups in STAT 3 immunofluorescence intensity at 2 h, and in STAT 3 protein expression at 2 h, 3 d and 1 W (P > 0.05). CONCLUSION: EA therapy can down-regulate the expression level of STAT 3 protein in the regional ischemic cerebral tissue in cerebral ischemia rats, which may contribute to its efficacy in the treatment of acute and chronic ischemic stroke.

Analysis of bilirubin UDP-glucuronosyltransferase gene mutations in an unusual Crigler-Najjar syndrome patient.

Crigler-Najjar (CN) syndrome is a rare autosomal recessive inherited disorder characterized by non-hemolytic, unconjugated hyperbilirubinemia. The levels of serum bilirubin and the response to phenobarbital treatment have been used to classify CN syndrome into two types: CN I and II. Mutations of the UGT1A1 gene have been found to be responsible for cases of CN syndrome. In the present study, the clinical features of a boy with an unusual type of CN syndrome were analysed. A DNA sample was obtained from the patient, and the promoter region, the exons and flanking intronic sequences of the UGT1A1 gene were analysed using the polymerase chain reaction and sequencing. The case was similar to CN type I in clinical features, but the therapeutic efficacy in the patient was superior to that typically observed in CN type II disease. Sequencing revealed compound heterozygous mutations, c.211G>A (p.G71R), c.1470C>T (p.D490D) and a normal homozygous A[TA]6TAA. No similar case has been reported worldwide and, considering the specific clinical features and therapeutic efficacy, a distinct type of CN was suspected. The phenotype of this unusual CN syndrome patient may be associated with the specific genotype.