Free radical-scavenging activity of Taiwanese native plants.

The 70% aqueous acetone extracts of ten Taiwanese native plants were evaluated by various antioxidant assays, including 1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl (.OH) radicals, and reducing power assay. In the present study, extracts of Acer buerferianum var. formosanum, Cleyera japonica var. morii, Cyclobalanopsis stenophylla var. stenophylloides, and Machilus zuihoensis exhibited stronger activity against DPPH radicals, and their IC50 values ranged from 5.4 to 8.3 microg/ml. The ten selected extracts effectively inhibited the formation of .OH generated in the Fenton reaction system. Among the extracts whose reducing power activities were determined, A. buerferianum var. formosanum, C. japonica var. morii, C. stenophylla var. stenophylloides, Eriobotrya deflex, and M. zuihoensis showed high activity. The results indicate the 70% aqueous acetone extracts of A. buerferianum var. formosanum, C. japonica var. morii, C. stenophylla var. stenophylloides, and M. zuihoensis with great potency in these assay systems and may be candidates for the development of natural antioxidants.     

Antibiotic stress-induced modulation of the endoribonucleolytic activity of RNase III and RNase G confers resistance to aminoglycoside antibiotics in Escherichia coli

Here, we report a resistance mechanism that is induced through the modulation of 16S ribosomal RNA (rRNA) processing on the exposure of Escherichia coli cells to aminoglycoside antibiotics. We observed decreased expression levels of RNase G associated with increased RNase III activity on rng mRNA in a subgroup of E. coli isolates that transiently acquired resistance to low levels of kanamycin or streptomycin. Analyses of 16S rRNA from the aminoglycoside-resistant E. coli cells, in addition to mutagenesis studies, demonstrated that the accumulation of 16S rRNA precursors containing 3–8 extra nucleotides at the 5’ terminus, which results from incomplete processing by RNase G, is responsible for the observed aminoglycoside resistance. Chemical protection, mass spectrometry analysis and cell-free translation assays revealed that the ribosomes from rng-deleted E. coli have decreased binding capacity for, and diminished sensitivity to, streptomycin and neomycin, compared with wild-type cells. It was observed that the deletion of rng had similar effects in Salmonella enterica serovar Typhimurium strain SL1344. Our findings suggest that modulation of the endoribonucleolytic activity of RNase III and RNase G constitutes a previously uncharacterized regulatory pathway for adaptive resistance in E. coli and related gram-negative bacteria to aminoglycoside antibiotics.     

CFTR: a missing link between exocrine and endocrine pancreas?

<正>Cystic fibrosis(CF),a life-shortening hereditary disease mainly afflicting people of Caucasian origins,is caused by loss-of-function mutations in the CFTR(Cystic Fibrosis Transmembrane conductance Regulator)gene,which encodes a phosphorylation-activated,but ATP-gated anion channel expressed primarily in epithelial cells.To date,nearly 2000 mutations have been identified as pathogenic,     

Effects of Buprenorphine and Estrous Cycle in a Murine Model of Cecal Ligation and Puncture

The effect of opioids on the immunopathology of sepsis models in mice has been controversial. In previous work, we showed that mortality and various inflammatory parameters did not differ between female mice given saline or buprenorphine after cecal ligation and puncture. To investigate further, we hypothesized that buprenorphine would not affect outcomes of sepsis at any stage of estrous. Female mice were allocated into 4 groups (n = 20 per group) according to stage of estrous. Mice then underwent cecal ligation and puncture and received either buprenorphine or saline. In 3-wk survival studies, overall survival did not differ between buprenorphine- and saline-treated mice. When mice were stratified according to stage of estrous, survival did not vary among saline-treated groups but was lower in buprenorphine-treated mice in metestrus compared with proestrus. To investigate inflammation as a potential mechanism for survival, we measured cell counts and cytokine levels in the peripheral blood and peritoneal lavage fluid at 12 and 24 h after cecal ligation and puncture. At 24 h, buprenorphine-treated mice in proestrus had more circulating neutrophils and monocytes than did saline-treated mice in proestrus and more circulating WBC than did mice in any other stage with or without buprenorphine. Our current results suggest that the effects of buprenorphine on a 50% survival model of sepsis in BALB/c female mice are minimal overall but that the stage of estrous has various effects in this model. Investigators should consider the effects of buprenorphine and estrous cycle when using female mice in sepsis research.Abbreviations: CLP, cecal ligation and punctureSepsis is a complex, multifactorial disease that remains a common cause of morbidity and mortality after events such as surgery, trauma, and burns.^2,27 Sepsis is difficult to investigate with a single animal model, but many researchers consider cecal ligation and puncture (CLP) in rodents the ‘gold standard’ in creating polymicrobial peritonitis.^5,18 However, several innate and environmental factors cause variability in CLP studies.One variable is the use of analgesia in rodents undergoing CLP. The use of perioperative analgesia for studies using major surgery is the standard of veterinary care. The 2011 Guide also reminds us that the appropriate use of analgesics in research animals is an “ethical and moral imperative.”²⁰ However, sepsis research focuses on the immune response during the course of the disease, and some analgesics, including nonsteroidal antiinflammatory drugs and opioids such as morphine and fentanyl, are known to have immunomodulatory effects.^31,37Buprenorphine is a safe and effective opioid analgesic¹⁶ for rodents and is considered to be minimally immunosuppressive.³¹ Our laboratory has shown that a specific dosing regimen of buprenorphine did not significantly affect survival or immune parameters in female ICR and C57BL/6 mice undergoing CLP,^7,19 whereas male C57BL/6 mice showed a dose-responsive decrease in survival. There were no obvious changes in immune parameters to explain the differences between male and female mice. However, there are known sex-associated differences in responses to opioids. Several reports show that opioids have greater potency, efficacy, and overall analgesia in male rodents than in female, although results looking specifically at buprenorphine are mixed.^8,35In addition to differences in response to opioids, gender may also play a role in the response to sepsis. In humans, several studies have shown that women are less susceptible to sepsis than men.^24,38 In contrast, a different group showed that women with sepsis have a worse survival rate than do men.²⁶ Similarly, contradictory literature in mice has shown either a higher or lower survival in female mice as compared with male in sepsis studies.^23,41 One possible factor for these contradictory results in both rodent and human studies is that female subjects were not grouped by phase of the estrous or menstrual cycle. In both mice and humans, fluctuations of estrogen and progesterone occur regularly through their respective cycles. Other hormonal factors such as prolactin, follicle stimulating hormone, and luteinizing hormone vary as well.¹⁴ Studies show that estrogen, prolactin, and other hormones can affect the immune system with and without sepsis,^1,22,42 leading to the concern that the changing hormonal status of female subjects may affect the responses to opioids and to sepsis. Although several sepsis and trauma studies in rodents look at specific stages of estrous^34,41 or the effects of exogenous estrogen,^9,10,33,39 few target CLP specifically, and none look at this issue in conjunction with buprenorphine.The purpose of our study was to investigate the effects of buprenorphine and the estrous cycle on a CLP model of sepsis. For these investigations, we chose to use female BALB/c mice to assess survival and immune responses. In addition, we performed survival experiments in male mice for comparison. Coupled with our previous studies, these findings will give a comprehensive profile of the major mouse strains used in sepsis research.     

Complete mitochondrial genome sequence of Pyropia yezoensis (Bangiales,Rhodophyta) from Korea

Species of the genera Porphyra and Pyropia are the major seaweed cultivars in Korea, Japan, and China. Genomic data from Porphyra/Pyropia species is now being used for molecular breeding and bioengineering. We determined the complete mitochondrial genome (mtDNA) sequence of Pyropia yezoensis (Bangiales, Rhodophyta) from Korea. Pyropia yezoensis mtDNA was 35,596 bp in size and exhibited high sequence similarity to Py. yezoensis mtDNA reported from China (NC_017837; 41,688 bp). However, the Korean Py. yezoensis differed from the Chinese strain in the presence/absence of introns and intronic open reading frames of the ribosomal RNA large subunit gene (rnl) and cytochrome c oxidase subunit 1 gene (cox1). These differences result in large variations between the mtDNA of the two strains of Py. yezoensis. Moreover, the Korean strain had a single copy of the trnfM–trnQ region, as compared to a duplicate copy of Py. yezoensis (NC_017837). Pyropia mtDNA exhibited unique genetic features at the intra- and interspecies levels. Therefore, mtDNA genomics can provide novel knowledge for red algal molecular systematics and help to differentiate between cultivars of Pyropia species with new molecular markers.     

Dynamic Reweighting of Three Modalities for Sensor Fusion

We simultaneously perturbed visual, vestibular and proprioceptive modalities to understand how sensory feedback is re-weighted so that overall feedback remains suited to stabilizing upright stance. Ten healthy young subjects received an 80 Hz vibratory stimulus to their bilateral Achilles tendons (stimulus turns on-off at 0.28 Hz), a ±1 mA binaural monopolar galvanic vestibular stimulus at 0.36 Hz, and a visual stimulus at 0.2 Hz during standing. The visual stimulus was presented at different amplitudes (0.2, 0.8 deg rotation about ankle axis) to measure: the change in gain (weighting) to vision, an intramodal effect; and a change in gain to vibration and galvanic vestibular stimulation, both intermodal effects. The results showed a clear intramodal visual effect, indicating a de-emphasis on vision when the amplitude of visual stimulus increased. At the same time, an intermodal visual-proprioceptive reweighting effect was observed with the addition of vibration, which is thought to change proprioceptive inputs at the ankles, forcing the nervous system to rely more on vision and vestibular modalities. Similar intermodal effects for visual-vestibular reweighting were observed, suggesting that vestibular information is not a “fixed” reference, but is dynamically adjusted in the sensor fusion process. This is the first time, to our knowledge, that the interplay between the three primary modalities for postural control has been clearly delineated, illustrating a central process that fuses these modalities for accurate estimates of self-motion.     

Gestational Diabetes Is Characterized by Reduced Mitochondrial Protein Expression and Altered Calcium Signaling Proteins in Skeletal Muscle

The rising prevalence of gestational diabetes mellitus (GDM) affects up to 18% of pregnant women with immediate and long-term metabolic consequences for both mother and infant. Abnormal glucose uptake and lipid oxidation are hallmark features of GDM prompting us to use an exploratory proteomics approach to investigate the cellular mechanisms underlying differences in skeletal muscle metabolism between obese pregnant women with GDM (OGDM) and obese pregnant women with normal glucose tolerance (ONGT). Functional validation was performed in a second cohort of obese OGDM and ONGT pregnant women. Quantitative proteomic analysis in rectus abdominus skeletal muscle tissue collected at delivery revealed reduced protein content of mitochondrial complex I (C-I) subunits (NDUFS3, NDUFV2) and altered content of proteins involved in calcium homeostasis/signaling (calcineurin A, α1-syntrophin, annexin A4) in OGDM (n = 6) vs. ONGT (n = 6). Follow-up analyses showed reduced enzymatic activity of mitochondrial complexes C-I, C-III, and C-IV (−60–75%) in the OGDM (n = 8) compared with ONGT (n = 10) subjects, though no differences were observed for mitochondrial complex protein content. Upstream regulators of mitochondrial biogenesis and oxidative phosphorylation were not different between groups. However, AMPK phosphorylation was dramatically reduced by 75% in the OGDM women. These data suggest that GDM is associated with reduced skeletal muscle oxidative phosphorylation and disordered calcium homeostasis. These relationships deserve further attention as they may represent novel risk factors for development of GDM and may have implications on the effectiveness of physical activity interventions on both treatment strategies for GDM and for prevention of type 2 diabetes postpartum.     

Genome-Wide Association Analysis of Radiation Resistance in Drosophila melanogaster

Background

Ionizing radiation is genotoxic to cells. Healthy tissue toxicity in patients and radiation resistance in tumors present common clinical challenges in delivering effective radiation therapies. Radiation response is a complex, polygenic trait with unknown genetic determinants. The Drosophila Genetic Reference Panel (DGRP) provides a model to investigate the genetics of natural variation for sensitivity to radiation.

Methods and Findings

Radiation response was quantified in 154 inbred DGRP lines, among which 92 radiosensitive lines and 62 radioresistant lines were classified as controls and cases, respectively. A case-control genome-wide association screen for radioresistance was performed. There are 32 single nucleotide polymorphisms (SNPs) associated with radio resistance at a nominal p<10⁻⁵; all had modest effect sizes and were common variants with the minor allele frequency >5%. All the genes implicated by those SNP hits were novel, many without a known role in radiation resistance and some with unknown function. Variants in known DNA damage and repair genes associated with radiation response were below the significance threshold of p<10⁻⁵ and were not present among the significant hits. No SNP met the genome-wide significance threshold (p = 1.49×10⁻⁷), indicating a necessity for a larger sample size.

Conclusions

Several genes not previously associated with variation in radiation resistance were identified. These genes, especially the ones with human homologs, form the basis for exploring new pathways involved in radiation resistance in novel functional studies. An improved DGRP model with a sample size of at least 265 lines and ideally up to 793 lines is recommended for future studies of complex traits.