PDEA-coated magnetic nanoparticles for gene delivery to Hep G2 cells

Poly(2-(diethylamino)ethyl methacrylate) coated magnetic nanoparticles (PDEA-MNPs) were synthesized as a new gene nanocarrier to delivery plasmids (pEGFPN1 and pRL-TK) into human hepatoma (Hep G2) cells. The PDEA-MNPs shows the pH-sensitive property. These nanoparticles are positively charged at acidic pH and negatively charged at neutral or alkaline pH. The PDEAMNPs exhibited a low cytotoxicity in Hep G2 cells. PDEA-MNPs could bind and protect DNA from DNase I degradation. The transfection study demonstrated that the PDEA-MNPs could carry plasmid into Hep G2 cells and exhibited a high gene transfection efficiency. These results indicated that the novel magnetic nanoparticles could enhance gene transfection in vitro and hold the potential to be a promising non-viral nanodevice.     

Lactobacillus paracasei subsp. paracasei LC01 positively modulates intestinal microflora in healthy young adults

Lactobacillus paracasei subsp. paracasei LC01 (LC01) can tolerate intestinal stresses and has antioxidant activity. To evaluate the effect of the bacterium on human intestinal microflora, a randomized, double-blind, placebo-controlled human trial was carried out. Fifty-two healthy adult volunteers were randomized equally to two groups. One group consumed 12% (wt/vol) skimmed milk supplemented with 10¹⁰ CFU of LC01 each day for the 4-week treatment period, and then consumed placebo in the next treatment period, separated by a 2-week washout. The other group followed the reverse order. Group-specific real-time PCR and biochemical analyses was used to determine the intestinal bacterial composition of fecal samples collected at the end of every period, and the concentration of short-chain fatty acids and ammonia. A significant inhibition in fecal Escherichia coli and increase in Lactobacillus, Bifidobacterium, and Roseburia intestinalis were observed after consumption of LC01. Acetic acid and butyric acid were significantly higher in the probiotic stage and fecal ammonia was significantly lower. The results indicated a modulation effect of LC01 on the intestinal microflora of young adults, suggesting a beneficial effect on bowel health. LC01 may have potential value as a probiotic.     

Phylogenetic position of Jaoa,a green algal genus endemic to China

Jaoa prasina, a freshwater green alga endemic to China, was collected from a stream in Hubei province, China. Unialgal cultivation, morphological observation, and phylogenetic analyses of small subunit ribosomal DNA and RuBisCO large subunit sequences were performed. When cultured on agar medium, the alga was irregularly filamentous, similar to marine species of Acrochaete. Aplanospores were observed on solid medium. A vesicular‐like thallus without rhizoids developed in liquid medium, similar to specimen development in natural habitats. Molecular phylogenetic analyses revealed that Jaoa was closely related to the marine genera Acrochaete Pringsheim and Ulvella Crouan & Crouan. The results suggested the genus Jaoa is a member of the family Ulvellaceae (Ulvophyceae), which contains mostly marine algae. The family name Jaoaceae should be abandoned. We speculate that Jaoa may have evolved from a marine Ulvellaceae ancestor.     

Fabrication of 14 different RNA nanoparticles for specific tumor targeting without accumulation in normal organs

Due to structural flexibility, RNase sensitivity, and serum instability, RNA nanoparticles with concrete shapes for in vivo application remain challenging to construct. Here we report the construction of 14 RNA nanoparticles with solid shapes for targeting cancers specifically. These RNA nanoparticles were resistant to RNase degradation, stable in serum for >36 h, and stable in vivo after systemic injection. By applying RNA nanotechnology and exemplifying with these 14 RNA nanoparticles, we have established the technology and developed “toolkits” utilizing a variety of principles to construct RNA architectures with diverse shapes and angles. The structure elements of phi29 motor pRNA were utilized for fabrication of dimers, twins, trimers, triplets, tetramers, quadruplets, pentamers, hexamers, heptamers, and other higher-order oligomers, as well as branched diverse architectures via hand-in-hand, foot-to-foot, and arm-on-arm interactions. These novel RNA nanostructures harbor resourceful functionalities for numerous applications in nanotechnology and medicine. It was found that all incorporated functional modules, such as siRNA, ribozymes, aptamers, and other functionalities, folded correctly and functioned independently within the nanoparticles. The incorporation of all functionalities was achieved prior, but not subsequent, to the assembly of the RNA nanoparticles, thus ensuring the production of homogeneous therapeutic nanoparticles. More importantly, upon systemic injection, these RNA nanoparticles targeted cancer exclusively in vivo without accumulation in normal organs and tissues. These findings open a new territory for cancer targeting and treatment. The versatility and diversity in structure and function derived from one biological RNA molecule implies immense potential concealed within the RNA nanotechnology field.     

Improvements in the primary culture of neonate rat myocardial cells by study of the mechanism of endoplasmic reticulum stress

We previously found that endoplasmic reticulum stress (ERS) might be exhibited in the conventional protocol of the primary culture of neonate rat myocardial cells (NRMCs) and that the high glucose concentration (25 mmol/L) in the culture medium might be the cause. Here, we investigated if the high concentration of glucose might influence ERS in myocardial cells during culture. GRP78 expression (ERS marker) was similar in groups with tunicamycin (TM) and without TM in high glucose cultured cells (p?>?0.01). Different glucose concentrations elicited different GRP78 expressions according to analyses of protein and RNA levels, which showed ERS in H/H groups. Finally, we found that GRP78 expression was higher in TM groups compared with M/M groups (p?<?0.01). The conventional high-glucose culture media during primary culture of NRMCs induced ERS. We propose that medium-glucose culture media should be used and describe an improved protocol for the primary culture of NRMCs.     

hPNAS-4 inhibits proliferation through S phase arrest and apoptosis: underlying action mechanism in ovarian cancer cells

PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Previous studies have shown that hPNAS-4 can inhibit tumor growth when over-expressed in ovarian cancer cells. However, the underlying action mechanism remains elusive. In this work, we found that hPNAS-4 expression was significantly increased in SKOV3 cells when exposed to cisplatin, methyl methanesulfonate or mitomycin C, and that its overexpression could induce proliferation inhibition, S phase arrest and apoptosis in A2780s and SKOV3 ovarian cancer cells. The S phase arrest caused by hPNAS-4 was associated with up-regulation of p21. p21 is p53-dispensable and correlates with activation of ERK, and activation of the Cdc25A-Cdk2-Cyclin E/Cyclin A pathway, while the pro-apoptotic effects of hPNAS-4 were mediated by activation of caspase-9 and -3 other than caspase-8, and accompanied by release of AIF, Smac and cytochrome c into the cytosol. Taken together, these data suggest a new mechanism by which hPNAS-4 inhibits proliferation of ovarian cancer cells by inducing S phase arrest and apoptosis via activation of Cdc25A-Cdk2-Cyclin E/Cyclin A axis and mitochondrial dysfunction-mediated caspase-dependent and -independent apoptotic pathways. To our knowledge, we provide the first molecular evidence for the potential application of hPNAS-4 as a novel target in ovarian cancer gene therapy.     

Th1/Th2/Th17/Treg cytokines in Guillain–Barré syndrome and experimental autoimmune neuritis

Guillain–Barré syndrome (GBS) is an immune-mediated acute inflammatory disorder in the peripheral nervous system (PNS) of humans characterized by inflammatory infiltration and damage to myelin and axon. Experimental autoimmune neuritis (EAN) is a useful animal model for GBS. Although GBS and EAN have been widely studied, the pathophysiological basis of GBS/EAN remains largely unknown. Immunocompetent cells together with cytokines produced by various cells contribute to the inflammatory process of EAN by acting as mediators or effectors. Both GBS and EAN have hitherto been attributed to T helper (Th)1 cells-mediated disorders, however, some changes in GBS and EAN could not be explained by the pathogenic role of Th1 cells and a disturbance of the Th1/Th2 balance, which has previously been considered to be important for the homeostatic maintenance of the immune responses and to explain the adaptive immunity and autoimmune diseases. The Th1/Th2 paradigm in autoimmune diseases has been greatly challenged in recent years, with the identification of a particular T cell subset Th17 cells. Studies on the associations between Th17 cells/cytokines and GBS/EAN are reviewed. But some of them occasionally yield conflicting results, indicating an intricate network of cytokines in immune response.     

A New Coronary Retroinfusion Technique in theRat Infarct Model: Transjugular Cardiac Vein Catheterization

Cell delivery via the retrograde coronary route boasts less vessel embolism, myocardial injury, and arrhythmogenicity when compared with those via antegrade coronary administration or myocardial injection. However, conventional insertion into the coronary sinus and consequent bleeding complication prevent its application in small animals. To overcome the complication of bleeding, we described a modified coronary retroinfusion technique via the jugular vein route in rats with myocardial infarction (MI). A flexible wire with a bent end was inserted into the left internal jugular vein and advanced slowly along the left superior vena cava. Under direct vision, the wire was run into the left cardiac vein by rotating the wire and changing the position of its tip. A fine tube was then advanced along the wire to the left cardiac vein. This modified technique showed less lethal hemorrhage than the conventional technique. Retroinfusion via transjugular catheter enabled efficient fluid or cell dissemination to the majority areas of the free wall of the left ventricle, covering the infarcted anterior wall. In conclusion, transjugular cardiac vein catheterization may make retrocoronary infusion a more safe and practical route for delivering cell, drug, and gene therapy into the infarcted myocardium of rats.     

The impacts of climate change and human activities on biogeochemical cycles on the Qinghai‐Tibetan Plateau

With a pace of about twice the observed rate of global warming, the temperature on the Qinghai‐Tibetan Plateau (Earth's ‘third pole’) has increased by 0.2 °C per decade over the past 50 years, which results in significant permafrost thawing and glacier retreat. Our review suggested that warming enhanced net primary production and soil respiration, decreased methane (CH₄) emissions from wetlands and increased CH₄ consumption of meadows, but might increase CH₄ emissions from lakes. Warming‐induced permafrost thawing and glaciers melting would also result in substantial emission of old carbon dioxide (CO₂) and CH₄. Nitrous oxide (N₂O) emission was not stimulated by warming itself, but might be slightly enhanced by wetting. However, there are many uncertainties in such biogeochemical cycles under climate change. Human activities (e.g. grazing, land cover changes) further modified the biogeochemical cycles and amplified such uncertainties on the plateau. If the projected warming and wetting continues, the future biogeochemical cycles will be more complicated. So facing research in this field is an ongoing challenge of integrating field observations with process‐based ecosystem models to predict the impacts of future climate change and human activities at various temporal and spatial scales. To reduce the uncertainties and to improve the precision of the predictions of the impacts of climate change and human activities on biogeochemical cycles, efforts should focus on conducting more field observation studies, integrating data within improved models, and developing new knowledge about coupling among carbon, nitrogen, and phosphorus biogeochemical cycles as well as about the role of microbes in these cycles.