Inhibition of GluN2D-Containing NMDA Receptors Protects Dopaminergic Neurons against 6-OHDA-Induced Neurotoxicity via Activating ERK/NRF2/HO-1 Signaling.

Abnormal glutamate signaling is implicated in the heightened vulnerability of dopaminergic neurons in Parkinson's disease (PD). NMDA receptors are ion-gated glutamate receptors with high calcium permeability, and their GluN2D subunits are prominently distributed in the basal ganglia and brainstem nuclei. Previous studies have reported that dopamine depletion led to the dysfunctions of GluN2D-containing NMDA receptors in PD animal models. However, it remains unknown whether selective modulation of GluN2D could protect dopaminergic neurons against neurotoxicity in PD. In this study, we found that allosteric activation of GluN2D-containing NMDA receptors decreased the cell viability of MES23.5 dopaminergic cells and the GluN2D inhibitor, QNZ46, showed antioxidant effects and significantly relieved apoptosis in 6-OHDA-treated cells. Meanwhile, we demonstrated that QNZ46 might act via activation of the ERK/NRF2/HO-1 pathway. We also verified that QNZ46 could rescue abnormal behaviors and attenuate dopaminergic cell loss in a 6-OHDA-lesioned rat model of PD. Although the precise mechanisms underlying the efficacy of QNZ46 in vivo remain elusive, the inhibition of the GluN2D subunit should be a considerable way to treat PD. More GluN2D-selective drugs, which present minimal side effects and broad therapeutic windows, need to be developed for PD treatment in future studies.

LRRK2 G2019S promotes astrocytic inflammation induced by oligomeric α-synuclein through NF-κB pathway.

Parkinson's disease (PD) is characterized by the irreversible loss of dopaminergic neurons and the accumulation of α-synuclein in Lewy bodies. The oligomeric α-synuclein (O-αS) is the most toxic form of α-synuclein species, and it has been reported to be a robust inflammatory mediator. Mutations in Leucine-Rich Repeat Kinase 2 (LRRK2) are also genetically linked to PD and neuroinflammation. However, how O-αS and LRRK2 interact in glial cells remains unclear. Here, we reported that LRRK2 G2019S mutation, which is one of the most frequent causes of familial PD, enhanced the effects of O-αS on astrocytes both in vivo and in vitro. Meanwhile, inhibition of LRRK2 kinase activity could relieve the inflammatory effects of both LRRK2 G2019S and O-αS. We also demonstrated that nuclear factor κB (NF-κB) pathway might be involved in the neuroinflammatory responses. These findings revealed that inhibition of LRRK2 kinase activity may be a viable strategy for suppressing neuroinflammation in PD.

PACAP/PAC1-R activation contributes to hyperalgesia in 6-OHDA-induced Parkinson's disease model rats via promoting excitatory synaptic transmission of spinal dorsal horn neurons.

Pain is a common annoying non-motor symptom in Parkinson's disease (PD) that causes distress to patients. Treatment for PD pain remains a big challenge, as its underlying mechanisms are elusive. Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor PAC1-R play important roles in regulating a variety of pathophysiological processes. In this study, we investigated whether PACAP/PAC1-R signaling was involved in the mechanisms of PD pain. 6-hydroxydopamine (6-OHDA)-induced PD model was established in rats. Behavioral tests, electrophysiological and Western blotting analysis were conducted 3 weeks later. We found that 6-OHDA rats had significantly lower mechanical paw withdrawal 50% threshold in von Frey filament test and shorter tail flick latency, while mRNA levels of Pacap and Adcyap1r1 (gene encoding PAC1-R) in the spinal dorsal horn were significantly upregulated. Whole-cell recordings from coronal spinal cord slices at L4-L6 revealed that the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in dorsal horn neurons was significantly increased, which was reversed by application of a PAC1-R antagonist PACAP 6-38 (250 nM). Furthermore, we demonstrated that intrathecal microinjection of PACAP 6-38 (0.125, 0.5, 2 µg) dose-dependently ameliorated the mechanical and thermal hyperalgesia in 6-OHDA rats. Inhibition of PACAP/PAC1-R signaling significantly suppressed the activation of Ca2+/calmodulin-dependent protein kinase II and extracellular signal-regulated kinase (ERK) in spinal dorsal horn of 6-OHDA rats. Microinjection of pAAV-Adcyap1r1 into L4-L6 spinal dorsal horn alleviated hyperalgesia in 6-OHDA rats. Intrathecal microinjection of ERK antagonist PD98059 (10 µg) significantly alleviated hyperalgesia in 6-OHDA rats associated with the inhibition of sEPSCs in dorsal horn neurons. In addition, we found that serum PACAP-38 concentration was significantly increased in PD patients with pain, and positively correlated with numerical rating scale score. In conclusion, activation of PACAP/PAC1-R induces the development of PD pain and targeting PACAP/PAC1-R is an alternative strategy for treating PD pain.

Early Enteral Nutrition and Sepsis-Associated Acute Kidney Injury: A Propensity Score Matched Cohort Study Based on the MIMIC-III Database.

PURPOSE: We aimed to analyze the optimal timing of enteral nutrition (EN) in the treatment of sepsis and its effect on sepsis-associated acute kidney injury (SA-AKI.). MATERIALS AND METHODS: The MIMIC-III database was employed to identify patients with sepsis who had received EN. With AKI as the primary outcome variable, receiver operating characteristic (ROC) curves were utilized to calculate the optimal cut-off time of early EN (EEN). Propensity score matching (PSM) was employed to control confounding effects. Logistic regressions and propensity score-based inverse probability of treatment weighting were utilized to assess the robustness of our findings. Comparisons within the EEN group were performed. RESULTS: 2364 patients were included in our study. With 53 hours after intensive care units (ICU) admission as the cut-off time of EEN according to the ROC curve, 1212 patients were assigned to the EEN group and the other 1152 to the delayed EN group. The risk of SA-AKI was reduced in the EEN group (odds ratio 0.319, 95% confidence interval 0.245-0.413, p<0.001). The EEN patients received fewer volumes (mL) of intravenous fluid (IVF) during their ICU stay (3750 mL vs. 5513.23 mL, p<0.001). The mediating effect of IVF was significant (p<0.001 for the average causal mediation effect). No significant differences were found within the EEN group (0-48 hours vs. 48-53 hours), except that patients initiating EN within 48 hours spent fewer days in ICU and hospital. CONCLUSION: EEN is associated with decreased risk of SA-AKI, and this beneficial effect may be proportionally mediated by IVF volume.

Astragaloside IV alleviates cytarabine-induced intestinal mucositis by remodeling macrophage polarization through AKT signaling.

BACKGROUND: Intestinal mucositis (IM) is one of the common side effects of chemotherapy with Cytarabine (Ara-C) and contributes to the major dose-limiting factor of chemotherapy, while the effective drug for IM is little. Astragalus, one of the main active components extrated from the roots of Astragalus membranaceus (AS-IV), is a common Chinese herbal medicine used in gastrointestinal diseases. However, the effect and mechanism of AS-IV on IM is unclear. Accumulating evidence suggests that M1 macrophages play a pivotal role in IM progression. PURPOSE: The purpose of the study was to explore the protection of AS-IV and its potential molecular mechanism on intestinal mucositis injury induced by Ara-C. METHOD: The protective effect of AS-IV was investigated in LPS-induced macrophages and Ara-C-induced intestinal mucositis mouse model. H&E, immunofluorescence and western blotting were used to evaluate the damage in different doses of Ara-C. Silencing AKT targeted by siRNA was performed to explore the potential mechanisms regulating macrophage polarization effect of Ara-C, which was investigated by CCK-8, immunofluorescence and western blotting. Flow cytometry, immunofluorescence and Western blotting were used to detect macrophage surface marker proteins and inflammatory genes to explore the potential molecular mechanism of AS-IV regulating macrophage polarization. RESULTS: The Cytarabine intervention at dose of 100mg/kg significantly induced IM in mice, with the ileum the most obvious site of injury, accompanied by decreased intestinal barrier, intestinal macrophage polarization to M1 and inflammation response. The administration of AS-IV improved weight loss, food intake, ileal morphological damage, intestinal barrier destruction and inflammatory factor release in mice induced by Ara-c, and also suppressed macrophage polarization to M1, regulating in phenotypic changes in macrophages. In vitro, the expression of M1 macrophage surface marker protein was markedly decreased in LPS-induced macrophages after silencing AKT. Similarly, the western blotting of intestinal tissues and molecular docking indicated that the key mechanisms of AS-IV were remodel AKT signaling, and finally regulating M1 macrophages and decrease inflammation response. CONCLUSION: Our study highlights that AS-IV exerts protective effect in Ara-C-induced IM through inhibit polarization to M1 macrophages based on AKT, and AS-IV may serve as a novel AKT inhibitor to counteract the intestinal adverse effects of chemotherapeutic agents.

Early-Life Stress Induces Prodromal Features of Parkinsonism in Ageing Rats.

Early-life stress (ELS) can cause long-term effects on human health, ranging from adolescence to adulthood, and even to gerontic. Although clinical retrospective data suggest that ELS may be related to senile neurodegenerative diseases such as Parkinson's disease (PD), there are few prospective investigations to explore its real contribution to PD. Here, we investigated the behavioral, histochemical, neuromorphological, and transcriptional changes induced by maternal separation (MS), an ELS model. Without neurotoxin, MS rats showed behavioral alterations in olfaction, locomotion, and gait characters after depression compared with control rats. Based on neuroimaging and histochemistry, although we found that the dopaminergic system in the striatum was impaired after MS, the decrease of striatal dopamine level was ~33%. Consistently, tyrosine hydroxylase immunostaining positive neurons of MS rats in the substantia nigra showed deficit by about 20% in cell counting. Furthermore, using transcriptome sequencing, we discovered many differentially expressed genes (DEGs) of MS rats in the striatum significantly enriched in the pathway of dopaminergic synapse, and the biological process of locomotion and neuromuscular process controlling balance. Encouragingly, some representative DEGs relating to PD were singled out. These results suggest that ELS-depression rats potentially mimic some key features of prodromal stage of PD during natural senescence. In conclusion, our findings provide some novel insights into the future pathogenesis and therapeutic studies for PD related to depression.

Induction of Parkinsonian-Like Changes via Targeted Downregulation of Astrocytic Glutamate Transporter GLT-1 in the Striatum.

BACKGROUND: Previous investigations have suggested that decreased expression of glutamate transporter-1 (GLT-1) is involved in glutamate excitotoxicity and contribute to the development of Parkinson's disease (PD), GLT-1 is decreased in animal models of PD. GLT-1 is mainly expressed in astrocytes, and the striatum is a GLT-1-rich brain area. OBJECTIVE: The aim was to explore the function and mechanism of astrocytic GLT-1 in PD-like changes. METHODS: In the study, PD-like changes and their molecular mechanism in rodents were tested by a behavioral assessment, micro-positron emission tomography/computed tomography (PET/CT), western blotting, immunohistochemical and immunofluorescence staining, and high performance liquid chromatography pre-column derivatization with O-pthaldialdehida after downregulating astrocytic GLT-1 in vivo and in vitro. RESULTS: In vivo, after 6 weeks of brain stereotactic injection of adeno-associated virus into the striatum, rats in the astrocytic GLT-1 knockdown group showed poorer motor performance, abnormal gait, and depression-like feature; but no olfactory disorders. The results of micro-PET/CT and western blotting indicated that the dopaminergic system was impaired in astrocytic GLT-1 knockdown rats. Similarly, tyrosine hydroxylase (TH) positive immune-staining in neurons of astrocytic GLT-1 knockdown rats showed deficit in cell count. In vitro, knockdown of astrocytic GLT-1 via RNA interference led to morphological injury of TH-positive neurons, which may be related to the abnormal calcium signal induced by glutamate accumulation after GLT-1 knockdown. Furthermore, the GLT-1 agonist ceftriaxone showed a protective effect on TH-positive neuron impairment. CONCLUSION: The present findings may shed new light in the future prevention and treatment of PD based on blocking glutamate excitotoxicity.

Spinal cord stimulation reduces cardiac pain through microglial deactivation in rats with chronic myocardial ischemia.

Angina pectoris is cardiac pain that is a common clinical symptom often resulting from myocardial ischemia. Spinal cord stimulation (SCS) is effective in treating refractory angina pectoris, but its underlying mechanisms have not been fully elucidated. The spinal dorsal horn is the first region of the central nervous system that receives nociceptive information; it is also the target of SCS. In the spinal cord, glial (astrocytes and microglia) activation is involved in the initiation and persistence of chronic pain. Thus, the present study investigated the possible cardiac pain­relieving effects of SCS on spinal dorsal horn glia in chronic myocardial ischemia (CMI). CMI was established by left anterior descending artery ligation surgery, which induced significant spontaneous/ongoing cardiac pain behaviors, as measured using the open field test in rats. SCS effectively improved such behaviors as shown by open field and conditioned place preference tests in CMI model rats. SCS suppressed CMI­induced spinal dorsal horn microglial activation, with downregulation of ionized calcium­binding adaptor protein­1 expression. Moreover, SCS inhibited CMI­induced spinal expression of phosphorylated­p38 MAPK, which was specifically colocalized with the spinal dorsal horn microglia rather than astrocytes and neurons. Furthermore, SCS could depress spinal neuroinflammation by suppressing CMI­induced IL­1ß and TNF­α release. Intrathecal administration of minocycline, a microglial inhibitor, alleviated the cardiac pain behaviors in CMI model rats. In addition, the injection of fractalkine (microglia­activating factor) partially reversed the SCS­produced analgesic effects on CMI­induced cardiac pain. These results indicated that the therapeutic mechanism of SCS on CMI may occur partially through the inhibition of spinal microglial p38 MAPK pathway activation. The present study identified a novel mechanism underlying the SCS­produced analgesic effects on chronic cardiac pain.

Pramipexole regulates depression-like behavior via dopamine D3 receptor in a mouse model of Parkinson's disease.

Depression is one of the strongest predictors of quality of life in patients with Parkinson's disease (PD). Despite the high prevalence of depression, there is no clear guidance for its treatment in PD because the evidence for the efficacy of most antidepressants remains insufficient. Pramipexole, a dopamine agonist, is one of the few drugs that has proven to be clinically useful. However, the underlying mechanisms of antidepressive effects of pramipexole are still unknown. A 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model, dopamine D2 receptor (DRD2) and D3 receptor (DRD3) knockout mice were used in our study. Compared with other dopamine D2-like receptor agonists and madopar, pramipexole improved depression-like behavior and alleviate bradykinesia in an MPTP-induced mouse model of PD. Pramipexole significantly improved depression-like behavior in DRD2-/- mice but not in DRD3-/- mice. These results demonstrate that the antidepressive effect of pramipexole is mediated by DRD3 but not DRD2. Our findings highlight the need to develop novel dopamine agonists specifically targeting DRD3 for the treatment of depression in PD in the future.

Advances of Zebrafish in Neurodegenerative Disease: From Models to Drug Discovery.

Neurodegenerative disease (NDD), including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, are characterized by the progressive loss of neurons which leads to the decline of motor and/or cognitive function. Currently, the prevalence of NDD is rapidly increasing in the aging population. However, valid drugs or treatment for NDD are still lacking. The clinical heterogeneity and complex pathogenesis of NDD pose a great challenge for the development of disease-modifying therapies. Numerous animal models have been generated to mimic the pathological conditions of these diseases for drug discovery. Among them, zebrafish (Danio rerio) models are progressively emerging and becoming a powerful tool for in vivo study of NDD. Extensive use of zebrafish in pharmacology research or drug screening is due to the high conserved evolution and 87% homology to humans. In this review, we summarize the zebrafish models used in NDD studies, and highlight the recent findings on pharmacological targets for NDD treatment. As high-throughput platforms in zebrafish research have rapidly developed in recent years, we also discuss the application prospects of these new technologies in future NDD research.

Advances in intranasal application of stem cells in the treatment of central nervous system diseases.

Stem cells are characterized by their self-renewal and multipotency and have great potential in the therapy of various disorders. However, the blood-brain barrier (BBB) limits the application of stem cells in the therapy of neurological disorders, especially in a noninvasive way. It has been shown that small molecular substances, macromolecular proteins, and even stem cells can bypass the BBB and reach the brain parenchyma following intranasal administration. Here, we review the possible brain-entry routes of transnasal treatment, the cell types, and diseases involved in intranasal stem cell therapy, and discuss its advantages and disadvantages in the treatment of central nervous system diseases, to provide a reference for the application of intranasal stem cell therapy.

Comparison between video-assisted retroperitoneal debridement and small incision pancreatic necrosectomy in infected pancreatic necrosis.

BACKGROUND: Debridement and drainage have always been mainstream treatment for infected pancreatic necrosis (IPN), and the application of minimally invasive necrosectomy is becoming increasingly widespread. However, few studies have compared video-assisted retroperitoneal debridement (VARD) and small incision pancreatic necrosectomy (SIPN) individually. Our aim was to compare VARD and SIPN by evaluating outcomes. METHODS: We retrospectively reviewed patients with IPN who underwent either VARD or SIPN between 2010 and 2019 in China. Data relative to patient demographics, major complications, health care resource utilization and mortality were collected. Statistical analyses used were the two-tailed Student's t-test and the chi-squared test. RESULTS: Of 59 patients, 31 patients underwent SIPN and 28 patients were treated with VARD. SIPN and VARD had similar treatment success and mortality rates. The rate of reintervention due to lack of clinical improvement was significantly lower in the SIPN group (32% versus 61%; P = 0.028). In addition, the length of total hospital stay was 60 days in the SIPN group and 72 days in the VARD group (P < 0.0001) and mean total costs was significantly less in the SIPN group than in the VARD group (P = 0.008). CONCLUSION: Given the shorter hospitalization period, lower total cost and lower rate of reinterventions, SIPN may be superior to the step-up approach for patients with IPN than for those with VARD.

ADATMS-7 regulates the focal adhesion kinase signaling and promotes invasiveness of trophoblasts in early pregnancy.

INTRODUCTION: ADAMTS-7, a member of the disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, was recently identified to be associated with cell migration and invasion. However, its function on trophoblasts remains unknown. In this study, we are aimed to investigate the role of ADAMTS-7 on trophoblasts in human first trimester gestation. METHODS: The expression of ADAMTS-7 in trophoblasts and HTR8/SVneo cells is examined by immunohistochemistry and quantitative real-time PCR. BrdU incorporation and Annexin V/PI staining are utilized to measure the effect of ADAMTS-7 on the proliferation and apoptosis of HTR8/SVneo cells, respectively. In addition, we detect the role of ADAMTS-7 on the invasion ability of HTR8/SVneo cells using matrigel invasion assays. The activation of focal adhesion kinase (FAK) and integrinß1 induced by ADAMTS-7 were determined by Western blot. RESULTS: ADAMTS-7 and its substrate cartilage oligomeric matrix protein (COMP) were expressed in both primary human trophoblasts and human trophoblast cell lines. TGF-ß1 induced a continuous and significant decrease of ADAMTS-7. Inversely, IL-1ß up-regulated the ADAMTS-7 level in a dosage dependent manner. In addition, knockdown of ADAMTS-7 inhibited the growth and invasion of HTR8/SVneo cells. To the contrary, ADAMTS-7 overexpression promoted the growth and invasion of HTR8/SVneo cells. ADAMTS-7 knockdown led to a decreased level of FAK Tyr-397 phosphorylation. DISCUSSION: Our results suggest that ADAMTS-7 may regulate trophoblasts invasion through focal adhesion kinase (FAK) signaling.

Roles for IFT172 and Primary Cilia in Cell Migration, Cell Division, and Neocortex Development.

The cilium of a cell translates varied extracellular cues into intracellular signals that control embryonic development and organ function. The dynamic maintenance of ciliary structure and function requires balanced bidirectional cargo transport involving intraflagellar transport (IFT) complexes. IFT172 is a member of the IFT complex B, and IFT172 mutation is associated with pathologies including short rib thoracic dysplasia, retinitis pigmentosa and Bardet-Biedl syndrome, but how it underpins these conditions is not clear. We used the WIM cell line, derived from embryonic fibroblasts of Wimple mice (carrying homozygous Leu1564Pro mutation in Ift172), to probe roles of Ift172 and primary cilia in cell behavior. WIM cells had ablated cilia and deficiencies in directed migration (electrotaxis), cell proliferation and intracellular signaling. Additionally, WIM cells displayed altered cell cycle progression, with increased numbers of chromatids, highlighting dysfunctional centrosome status. Exposure to a physiological electric field promoted a higher percentage of primary cilia in wild-type cells. Interestingly, in situ hybridization revealed an extensive and dynamic expression profile of Ift172 in both developing and adult mouse cortex. In vivo manipulation of Ift172 expression in germinal regions of embryonic mouse brains perturbed neural progenitor proliferation and radial migration of post-mitotic neurons, revealing a regulatory role of Ift172 in cerebral morphogenesis. Our data suggest that Ift172 regulates a range of fundamental biological processes, highlighting the pivotal roles of the primary cilium in cell physiology and brain development.

Structural Basis of the Proton Sensitivity of Human GluN1-GluN2A NMDA Receptors.

N-methyl-D-aspartate (NMDA) receptors are critical for synaptic development and plasticity. While glutamate is the primary agonist, protons can modulate NMDA receptor activity at synapses during vesicle exocytosis by mechanisms that are unknown. We used cryo-electron microscopy to solve the structures of the human GluN1-GluN2A NMDA receptor at pH 7.8 and pH 6.3. Our structures demonstrate that the proton sensor predominantly resides in the N-terminal domain (NTD) of the GluN2A subunit and reveal the allosteric coupling mechanism between the proton sensor and the channel gate. Under high-pH conditions, the GluN2A-NTD adopts an "open-and-twisted" conformation. However, upon protonation at the lower pH, the GluN2A-NTD transits from an open- to closed-cleft conformation, causing rearrangements between the tetrameric NTDs and agonist-binding domains. The conformational mobility observed in our structures (presumably from protonation) is supported by molecular dynamics simulation. Our findings reveal the structural mechanisms by which protons allosterically inhibit human GluN1-GluN2A receptor activity.

Oxytocin is implicated in social memory deficits induced by early sensory deprivation in mice.

Early-life sensory input plays a crucial role in brain development. Although deprivation of orofacial sensory input at perinatal stages disrupts the establishment of the barrel cortex and relevant callosal connections, its long-term effect on adult behavior remains elusive. In this study, we investigated the behavioral phenotypes in adult mice with unilateral transection of the infraorbital nerve (ION) at postnatal day 3 (P3). Although ION-transected mice had normal locomotor activity, motor coordination, olfaction, anxiety-like behaviors, novel object memory, preference for social novelty and sociability, they presented deficits in social memory and spatial memory compared with control mice. In addition, the social memory deficit was associated with reduced oxytocin (OXT) levels in the hypothalamus and could be partially restored by intranasal administration of OXT. Thus, early sensory deprivation does result in behavioral alterations in mice, some of which may be associated with the disruption of oxytocin signaling.

Deletion of autophagy-related gene 7 in dopaminergic neurons prevents their loss induced by MPTP.

Parkinson's disease (PD) is a neurodegenerative disease caused by a gradual loss of midbrain dopaminergic (mDA) neurons in the substantia nigra pars compacta (SNpc) during aging. 1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) is one of the neurotoxins used widely to induce PD-like symptoms in PD animal models, including rodents and non-human primates. It has been reported that deletion of autophagy-related gene 7 (Atg7) in the brain results in a reduction of mDA neurons in adulthood. In this study, we used tyrosine hydroxylase (TH)-Cre mice to generate conditional knockout (CKO) mice with the specific deletion of Atg7 in mDA neurons. Consistent with previous reports, adult Atg7 CKO mice contained fewer TH-positive mDA neurons compared with wild-type (WT) controls. TH-expressing neurons containing puncta-like structures with p62 and ubiquitin immunoreactivity were observed in the midbrain of Atg7 CKO mice but were not detected in control mice. However, MPTP-induced loss of mDA neurons was not observed in Atg7 CKO mice. Our results indicate that Atg7-involved autophagy is required not only for the survival of mDA neurons in the mouse brain, but also for MPTP-induced mDA neuron degeneration.

A new triterpenoid saponin from Gleditsia sinensis and its antiproliferative activity.

Chemical investigation of the anomalous fruits of Gleditsia sinensis led to the isolation and identification of a new triterpenoid saponin, 3-O-ß-D-xylopyranosyl-(1 â†’ 2)-α-L-arabinopyranosyl-(1 â†’ 6)-ß-D-glucopyranosyl oleanolic acid 28-O-ß-D-xylopyranosyl-(1 â†’ 4)-α-L-rhamnopyrano--syl-(1 â†’ 4)-ß-D-xylopyranosyl-(1 â†’ 4)-α-L-rhamnopyranosyl-(1 â†’ 3)-ß-D-glucopyranosyl ester (1), along with other nine known compounds (2-10). All the isolates from this species were reported for the first time. The structure of Compound 1 was determined by a detailed analysis using various analytical techniques, including 1D and 2D NMR. In vitro antiproliferative activities of Compound 1 on MCF-7 and Hep-G2 tumor cell lines were evaluated. IC50 values against the two cell lines were 9.5 and 11.6 µM, respectively.

Prevalence of 16S rRNA Methylase Gene rmtB Among Escherichia coli Isolated from Bovine Mastitis in Ningxia, China.

The aim of this study is to understand the prevalence and molecular characterization of 16S rRNA methylase gene, rmtB, among Escherichia coli strains isolated from bovine mastitis in China. A total of 245 E. coli isolates were collected from bovine mastitis in China between 2013 and 2014 and were screened for 16S rRNA methylase genes (armA, rmtA, rmtB, rmtC, rmtD, rmtE, and npmA) by polymerase chain reaction. About 5.3% (13/245) of the isolates carried the rmtB gene; the isolates were highly resistant to amikacin. Thirteen rmtB-positive strains were analyzed for the presence of extended-spectrum ß-lactamase genes (bla(TEM), bla(CTX-M), bla(OXA), and bla(SHV)). All the isolates harbored both bla(TEM-1) and bla(CTX-M-15) genes and two of the isolates were also positive for bla(OXA-1). Pulsed-field gel electrophoresis (PFGE) analysis indicated that the nine rmtB-positive strains belonging to ST10 from one farm showed the similar PFGE pattern, indicating a clonal expansion in this farm. S1-PFGE and Southern blotting showed that 12 isolates harbored the rmtB gene in plasmids of two different sizes (≈45 kb [n=10] and ≈48 kb [n=2]), while only 1 strain harbored the rmtB gene in the chromosome. These plasmids were transferable by conjugation studies, and two isolates from two respective farms carried the same size of plasmid, suggesting that the horizontal transmission of plasmids also contributed to the spread of rmtB gene. This is the first report of prevalence of the 16S rRNA methylase gene rmtB among E. coli isolated from bovine mastitis in China, and rmtB-carrying E. coli may pose a threat to the treatment of bovine mastitis.

Degradation of toluene-2,4-diamine by persulphate: kinetics, intermediates and degradation pathway.

In this study, the degradation of toluene-2,4-diamine (TDA) by persulphate (PS) in an aqueous solution at near-neutral pH was examined. The result showed that the degradation rate of TDA increased with increasing PS concentrations. The optimal dosage of PS in the reaction system was determined by efficiency indicator (I) coupling in the consumption of PS and decay half-life of TDA. Calculation showed that 0.74 mM of PS was the most effective dosage for TDA degradation, at that level the maximum I of 24.51 was obtained. PS can oxidize TDA for an extended reaction time period. Under neutral condition without activation, four degradation intermediates, 2,4-diamino-3-hydroxy-5-sulfonicacidtoluene, 2,4-diaminobenzaldehyde, 2,4-bis(vinylamino)benzaldehyde and 3,5-diamino-4-hydroxy-2-pentene, were identified by high-performance liquid chromatography-mass spectrometry. The tentative degradation pathway of TDA was proposed as well. It was found that hydroxyl radical played an important role in degradation of TDA with the activation of Fe2+, whereas PS anion and sulphate radicals were responsible for the degradation without activation of Fe2+.