Inhibition of retroviral Gag assembly by non-silencing miRNAs promotes autophagic viral degradation

We recently reported an unconventional mechanism by which miRNAs inhibit HIV-1 viral production. This occurs when miRNAs bind nonspecifically to the viral structural protein Gag, interfering with viral RNA-mediated Gag assembly at the plasma membrane. Consequently, misassembled viral complexes are redirected into the endocytic pathway where they are delivered to lysosomes for degradation. In this study, we demonstrate that autophagy is a critical mediator of the viral degradation pathway and that this pathway is not HIV-1 specific. Misassembled viral complexes were found to colocalize extensively with LC3 and p62 in late endosomes/lysosomes, demonstrating a convergence of autophagy with functional degradative compartments. Knocking down autophagosome formation machineries reduced this convergence, while treatment with autophagy-inducer rapamycin enhanced the convergence. Furthermore, similar autophagy-dependent nonspecific miRNA inhibition of murine leukemia virus (MLV) assembly was shown. Overall, these results reveal autophagy as a crucial regulator of the retroviral degradation pathway in host cells initiated by nonspecific miRNA-Gag interactions. These findings could have significant implications for understanding how cells may regulate retroviral complex assembly by miRNA expression and autophagy, and raise the possibility that similar regulations can occur in other biological contexts.

Establishment and application of multiplex direct PCR for rapid detection of common food borne pathogens in swine products / 中国人兽共患病学报

We established a multiplex direct PCR for rapid detection of E.coli,Salmonella,Staphylococcus aureus,Listeria and Yersinia enterocolitica bacteria.Multiplex direct PCR primers were designed according to gene sequences of phoA (E.coli),inv A (Salmonella),nuc (S.aureus),hl y (Listeria),and ail (Y.enterocolitica).After the multiplex direct PCR were established,the specificity and sensitivity of primers were detected.Then,multiplex direct PCR was applied to examine 60 swine product samples,the detection specificity,accuracy and positive predictive value were calculated compared with the gold standard culture method.Results showed that multiplex direct PCR primers could be used for specific detection of E.coli,Salmonella,S.aureus,Listeria and Y.enterocolitica,with the minimal detectable limit of 10,1,100,1 and 1 CFU,respectively.For the examination of 60 swine product samples using multiplex direct PCR,15 were positive for E.coli,6 positive for Salmonella,21 positive for S.aureus,20 positive for Listeria,and 35 positive for Y.enterocolitica,with all positive detection rates higher than that of culture.The total detection sensitivity was 100％,accuracy was 94％,and positive predictive value was 81.44％.Multiplex direct PCR could be used for specific and sensitive detection of common food-borne pathogens,and the testing time was shorten to be 3 hours because of saving time for template extraction.Multiplex direct PCR might serve the detection of food-borne pathogens in food safety risk monitoring much better.

Preparation and release behaviour of mPEG-PLA α-asarone nanoparticles designed for nasal administration / 中国中药杂志

Taking α-asarone as model drug, mono methoxy polyethylene glycol-polylactic acid copolymer (mPEG-PLA) as the drug carrier material to prepare drug-loading nanoparticles by premix membrane emulsification for nasal administration. The prepared nanoparticles were spherical with smooth surface and average particle size of 360 nm. Polydispersity index (PDI) was 0. 030, average drug loading of (11.5 ± 0.045) % (n = 3), and the encapsulation efficiency of (86.34 ± 0.11) % (n = 3). X-ray diffraction and differential scanning calorimetry results showed that, α-asarone existed in mPEG-PLA carrier in amorphous or molecular state, different from simple physical mixture. In the in vitro release test in simulated human nasal cavity, α-asarone apis can be released quickly at close to 94% at 102 h, in line with the first-order kinetics (R² = 0.981 9). mPEG-PLA drug-loading nanoparticles release only 54%, with slow release effect, in line with Riger-Peppas model (R² = 0.967 9, n = 0.630 2), for non-fick diffusion, released by the spread of drugs and skeleton dissolution dual control. This provided the foundation for nasal drug delivery in vivo pharmacokinetic study.

Comparison of Allergic Rhinitic Models Induced by Various Allergens / 中国药师

Objective:To compare the models of guinea pig allergic rhinitis induced by different allergens. Methods: Ovalbumin (OVA), 2,4-tolylene diisocyanate (TDI) and alternariaalternata was respectively used as the allergens to establish the model of guinea pigs allergic rhinitis. The conformity of the models and human allergic rhinitis was studied through the behavioral indices, such as the times of nose itches, nasal discharge flow, histological properties and serum HA and IgE indices. Results:The times of sneezing and scratching nose, serum HA and IgE in OVA group was significantly different from those in the control group (P<0. 001 or P<0. 01). Conclusion:The models of allergic rhinitis induced by OVA are the same as allergic rhinitis in typical symptoms and pathological changes.

Simulated microgravity-induced oxidative stress in different areas of rat brain / 生理学报

Microgravity is known to produce a number of neurological disturbances during space flight; however, the underlying mechanism of these disturbances is yet to be elucidated. There have been some reports about the increased oxidative stress under microgravity or simulated microgravity. In the present study, we investigated the process of oxidative stress induced by simulated microgravity in different areas of rat brain, which may shed light on the mechanism of neurological disturbances and further neuroprotective research in spaceflight. After adaption for 7 d, 40 healthy male Sprague-Dawley rats were matched for body weight and randomly assigned to control groups (7, 14, 21 and 28 d) and tail-suspended simulated microgravity groups (7, 14, 21 and 28 d). The tail-suspended groups were treated with 30 angels of tail suspension and the control groups were treated similarly to the tail-suspended groups but without tail suspension. After the required times, different structures of rat brain, including cerebellum, cerebral cortex and hippocampus, were harvested and frozen for the further determination. Griess assay, thiobarbituric acid reactive substance (TBARS) assay, competitive ELISA and ferric reducing ability of plasma (FRAP) assay were used for the observation of the changes of reactive nitrogen species (RNS), malondialdehyde (MDA), nitrotyrosine (NT) and total antioxidant capacity (TAC), respectively. As shown in the results, there were different changes in various brain regions after tail suspension compared with control groups. (1) In cerebellum, NT increased after 7 d tail suspension, decreased after 14 d and increased again after 28 d; MDA increased after 14 d; RNS increased and TAC decreased after tail suspension for 21 d; (2) Increase of NT after14 d tail suspension, increase of MDA and decrease of TAC after 21 d were found in cerebral cortex; (3) In hippocampus, RNS increased after tail suspension for 7 d, decreased after 14 d and increased again after 28 d; MDA increased after 21 d; NT increased after 28 d; TAC increased after 7 d and recovered after 21 d. These results suggest that simulated microgravity induced by tail suspension increases the level of oxidative stress in rat brain; however, there are different features in different areas of rat brain. During the response to simulated microgravity, rat brain tissues present a similar process from adaptive response to irreversible oxidative damage.

Effects of parabolic flight on redox status in SH-SY5Y cells / 生理学报

Space flight is known to produce a number of neurological disturbances. The etiology is unknown, but it may involve increased oxidative stress. A line of experimental evidence indicates that space flight may disrupt antioxidant defense system and result in increased oxidative stress. In vitro studies found that abundant of NO was produced in rat pheochromocytoma (PC12) cells, SHSY5Y neuroblastoma cells, and protein nitration was increased in PC12 cells within a simulated microgravity rotating wall bioreactor high aspect ratio vessel system or clinostat system. In the present study, we observed the change of redox status in SH-SY5Y cells after parabolic flight, and studied the effects of key redox molecule, thioredoxin (TRX), during the altered gravity. SH-SY5Y cells were divided into four groups: control cells, control cells transfected with TRX, flight cells and flight cells transfected with TRX. The expression levels of 3-nitrotyrosine (3-NT), inducible nitric oxide synthase (iNOS), TRX and thioredoxin reductase (TRXR) were observed by immunocytochemical method. It was shown that after parabolic flight, the staining of 3-NT and TRX were enhanced, while the expression level of TRXR was down-regulated compared with control. As for flight cells transfected with TRX, the staining of 3-NT and iNOS were weakened compared with flight cells. These results obtained suggest that altered gravity may increase protein nitration, down-regulate TRXR and elicit oxidative stress in SH-SY5Y cells, while TRX transfection could partly protect cells against oxidative stress induced by parabolic flight.