Physiological and transcriptomic analyses of leaves from Gardenia jasminoides Ellis under waterlogging stress.

Gardenia jasminoides Ellis is a Chinese herbal medicine with medicinal and economic value, but its mechanism of response to waterlogging stress remains unclear. In this study, the "double pots method" was used to simulate the waterlogging stress of Gardenia jasminoides Ellis to explore its physiological and transcriptomic response mechanism. We found no significant damage to Gardenia jasminoides Ellis membrane lipid during stress. POD played a vital antioxidant role, KEGG enrichment showed that secondary metabolites such as flavonoids might also play an antioxidant role, and PRO played a significant osmotic adjustment. Endogenous hormones regulate the Gardenia jasminoides Ellis's growth and development and play a role in signal transduction. Among them, light waterlogging stress is delayed. At the same time, there were 19631, 23693, and 15045 differentially expressed genes on the 5th, 10d, and 15d of Gardenia jasminoides Ellis under waterlogging stress. These genes were closely associated with the proteasome, endopeptidase, ribosome, MAPK signal transduction, and endogenous hormone signal transduction, plant-pathogen interaction and phenylpropanoid biosynthesis and other physiological and metabolic pathways, which regulate the turnover and transportation of protein, the reinforcement and adhesion of cell walls, the induction of stomatal closure, allergic reactions, defense reactions, leaf movements and others. It also can absorb ultraviolet rays to reduce the generation of oxygen free radicals, change the way of energy utilization and adjust the osmotic pressure of plant cells.

Association of oxidative stress and Kashin-Beck disease integrated Meta and Bioinformatics analysis.

OBJECTIVE: To explore the association between oxidative stress (OS) and Kashin-Beck disease (KBD). METHODS: Terms associated with "KBD" and "OS" were searched in the six different databases up to October 2021. Stata 14.0 was used to pool the means and standard deviations using random-effect or fixed-effect model. The differentially expressed genes in the articular chondrocytes of KBD were identified, the OS related genes were identified by blasting with the GeneCards. The KEGG pathway and gene ontology enrichment analysis was conducted using STRING. RESULTS: The pooled SMD and 95% CI showed hair selenium (-4.59; -6.99, -2.19), blood selenium (-1.65; -2.86, -0.44) and glutathione peroxidases (-4.15; -6.97, -1.33) levels were decreased in KBD, whereas the malondialdehyde (1.12; 0.60, 1.64), nitric oxide (2.29; 1.31, 3.27), nitric oxide synthase (1.07; 0.81, 1.33) and inducible nitric oxide synthase (1.69; 0.62, 2.77) were increased compared with external controls. Meanwhile, hair selenium (-2.71; -5.32, -0.10) and glutathione peroxidases (-1.00; -1.78, -0.22) in KBD were decreased, whereas the malondialdehyde (1.42; 1.04, 1.80), nitric oxide (3.08; 1.93, 4.22) and inducible nitric oxide synthase (0.81; 0.00, 1.61) were elevated compared with internal controls. Enrichment analysis revealed apoptosis was significantly correlated with KBD. The significant biological processes revealed OS induced the release of cytochrome c from mitochondria. The cellular component of OS located in the mitochondrial outer membrane. CONCLUSIONS: The OS levels in KBD were significantly increased because of selenium deficiency, OS mainly occurred in mitochondrial outer membrane, released of cytochrome c from mitochondria, and induced apoptotic signaling pathway.

Environmental impacts of nitrogen emissions in China and the role of policies in emission reduction.

Atmospheric reactive nitrogen (Nr) has been a cause of serious environmental pollution in China. Historically, China used too little Nr in its agriculture to feed its population. However, with the rapid increase in N fertilizer use for food production and fossil fuel consumption for energy supply over the last four decades, increasing gaseous Nr species (e.g. NH3 and NOx) have been emitted to the atmosphere and then deposited as wet and dry deposition, with adverse impacts on air, water and soil quality as well as plant biodiversity and human health. This paper reviews the issues associated with this in a holistic way. The emissions, deposition, impacts, actions and regulations for the mitigation of atmospheric Nr are discussed systematically. Both NH3 and NOx make major contributions to environmental pollution but especially to the formation of secondary fine particulate matter (PM2.5), which impacts human health and light scattering (haze). In addition, atmospheric deposition of NH3 and NOx causes adverse impacts on terrestrial and aquatic ecosystems due to acidification and eutrophication. Regulations and practices introduced by China that meet the urgent need to reduce Nr emissions are explained and resulting effects on emissions are discussed. Recommendations for improving future N management for achieving 'win-win' outcomes for Chinese agricultural production and food supply, and human and environmental health, are described. This article is part of a discussion meeting issue 'Air quality, past present and future'.

Omega-3 polyunsaturated fatty acids alleviate adenine-induced chronic renal failure via regulating ROS production and TGF-ß/SMAD pathway.

OBJECTIVE: To explore the role of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) in adenine-induced rat chronic renal failure and its underlying mechanism. MATERIALS AND METHODS: 30 Sprague Dawley (SD) rats were randomly assigned into three groups, namely sham group, adenine induction group (adenine group) and adenine induction + ω-3 PUFAs treatment group (ω-3 PUFAs group), with 10 rats in each group. Serum and kidney samples were collected after rats were sacrificed. Serum levels of Cr (creatinine) and BUN (urea nitrogen) were detected using commercial kits. HE (hematoxylin and eosin) staining was performed to evaluate the pathological changes of kidneys. Levels of oxidative stress indicators in rat kidney homogenate were detected by relative commercial kits, including SOD (superoxide dismutase), GSH (reduced glutathione), CAT (catalase), and T-AOC (total antioxidant capacity). Reactive oxygen species (ROS) production was also detected by immunofluorescence. Protein expressions of nuclear factor E2 related factor 2 (Nrf2) and transforming growth factor-beta (TGF-ß)/SMAD pathway-related genes were detected by Western blot. RESULTS: Serum levels of Cr and BUN in ω-3 PUFAs group were remarkably decreased compared with those of adenine group. Higher contents of SOD, GSH, CAT and T-AOC were observed in ω-3 PUFAs group compared with those of adenine group. Besides, MAD content and ROS production were lower in ω-3 PUFAs group than those of adenine group. Pathological changes of kidneys were alleviated after ω-3 PUFAs treatment. Western blot results demonstrated that ω-3 PUFAs treatment remarkably upregulates Nrf2, HO-1, NQO1, but downregulates relative genes in TGF-ß/SMAD pathway. CONCLUSIONS: ω-3 PUFAs alleviated adenine-induced chronic renal failure through enhancing antioxidant stress and inhibiting inflammatory response via regulating Nrf2 and TGF-ß/SMAD pathway.

Purification, characterization and application of a novel antimicrobial peptide from Andrias davidianus blood.

The Andrias davidianus has been known as a traditional Chinese medicine for a long time. Its blood is considered as a waste or by-product of the meat production industry. Although there are reports on isolation of the antimicrobial peptides from different resources, there are no reports of their isolation from A. davidianus blood. In this work, an antimicrobial peptide, andricin B, was isolated from the blood of A. davidianus by an innovative method in which the magnetic liposome adsorption was combined with reversed-phase high-performance liquid chromatography. The structure, antimicrobial activity and safety of andricin B were further investigated. Amino acid sequence was determined by N-terminal sequencing and found to be Gly-Leu-Thr-Arg-Leu-Phe-Ser-Val-Ile-Lys. Circular dichroism (CD) spectra and prediction of three-dimensional structure by bioinformatics software suggested the presence of a well-defined random coil conformation. Andricin B was found to be active against all bacteria tested in this study as well as some fungi. The minimum inhibitory concentrations (MICs) were in the range 8-64 µg ml-1 . Moreover, the haemolytic testing also suggested that andricin B could be considered safe at the MICs. Finally, andricin B was shown to inhibit the growth of Staphylococcus aureus in the cooked meat of A. davidianus. This study shows that andricin B is a promising novel antimicrobial peptide that may provide further insights towards the development of new drugs. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the pioneer study on screening and isolation of antimicrobial peptide from the blood of Andrias davidianus. Here, we have developed a novel method by combining magnetic liposomes adsorption with reversed-phase high-performance liquid chromatography to purify and screen the antimicrobial peptides. From this screen, we identified a novel antimicrobial peptide which we name as andricin B. Andricin B is unique as it checks the growth of both Gram-positive and Gram-negative bacteria as well as few fungal species.

Effects of dietary supplementation of resveratrol on performance, egg quality, yolk cholesterol and antioxidant enzyme activity of laying hens.

1. This experiment was conducted to evaluate the effects of dietary supplementation of resveratrol on laying performance, egg quality, egg yolk cholesterol and antioxidant enzyme activities of laying hens. 2. A total of 360 Beijing PINK-1 laying hens (60 weeks old) were randomly distributed among five dietary treatments, each of which included 6 replicates of 12 hens. Dietary treatments were basal diet supplemented with 0 (control), 0.5, 1.0, 2.0 and 4.0 g/kg diet resveratrol. The study lasted for 9 weeks including 1 week of adaptation and 8 weeks of the main experimental period. 3. The results indicated that dietary resveratrol significantly improved feed conversion ratios during 5-8 weeks and 1-8 weeks of the trial. Increasing dietary concentrations of the resveratrol linearly improved Haugh unit and albumen height of eggs. 4. The content of total cholesterol (TC), total triglyceride (TG), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C) in serum and cholesterol in yolk was significantly decreased by dietary resveratrol, and there were significant linear correlations between these indexes and resveratrol supplemental levels. 5. Dietary resveratrol supplementation significantly improved serum Glutathione peroxidase (GSH-Px) enzyme activity and decreased serum malondialdehyde (MDA) content in groups with 2.0 and 4.0 g/kg resveratrol as compared to the control, respectively. However, supplementation of resveratrol did not affect the activity of serum superoxide dismutase (SOD). 6. It is concluded that resveratrol supplementation has a positive effect on performance, lipid-related traits and antioxidant activity of laying hens.

Observation of three-component fermions in the topological semimetal molybdenum phosphide.

In quantum field theory, Lorentz invariance leads to three types of fermion-Dirac, Weyl and Majorana. Although the existence of Weyl and Majorana fermions as elementary particles in high-energy physics is debated, all three types of fermion have been proposed to exist as low-energy, long-wavelength quasiparticle excitations in condensed-matter systems. The existence of Dirac and Weyl fermions in condensed-matter systems has been confirmed experimentally, and that of Majorana fermions is supported by various experiments. However, in condensed-matter systems, fermions in crystals are constrained by the symmetries of the 230 crystal space groups rather than by Lorentz invariance, giving rise to the possibility of finding other types of fermionic excitation that have no counterparts in high-energy physics. Here we use angle-resolved photoemission spectroscopy to demonstrate the existence of a triply degenerate point in the electronic structure of crystalline molybdenum phosphide. Quasiparticle excitations near a triply degenerate point are three-component fermions, beyond the conventional Dirac-Weyl-Majorana classification, which attributes Dirac and Weyl fermions to four- and two-fold degenerate points, respectively. We also observe pairs of Weyl points in the bulk electronic structure of the crystal that coexist with the three-component fermions. This material thus represents a platform for studying the interplay between different types of fermions. Our experimental discovery opens up a way of exploring the new physics of unconventional fermions in condensed-matter systems.

Mitochondrial dysfunction-associated OPA1 cleavage contributes to muscle degeneration: preventative effect of hydroxytyrosol acetate.

Mitochondrial dysfunction contributes to the development of muscle disorders, including muscle wasting, muscle atrophy and degeneration. Despite the knowledge that oxidative stress closely interacts with mitochondrial dysfunction, the detailed mechanisms remain obscure. In this study, tert-butylhydroperoxide (t-BHP) was used to induce oxidative stress on differentiated C2C12 myotubes. t-BHP induced significant mitochondrial dysfunction in a time-dependent manner, accompanied by decreased myosin heavy chain (MyHC) expression at both the mRNA and protein levels. Consistently, endogenous reactive oxygen species (ROS) overproduction triggered by carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), a mitochondrial oxidative phosphorylation inhibitor, was accompanied by decreased membrane potential and decreased MyHC protein content. However, the free radical scavenger N-acetyl-L-cysteine (NAC) efficiently reduced the ROS level and restored MyHC content, suggesting a close association between ROS and MyHC expression. Meanwhile, we found that both t-BHP and FCCP promoted the cleavage of optic atrophy 1 (OPA1) from the long form into short form during the early stages. In addition, the ATPase family gene 3-like 2, a mitochondrial inner membrane protease, was also markedly increased. Moreover, OPA1 knockdown in myotubes was accompanied by decreased MyHC content, whereas NAC failed to prevent FCCP-induced MyHC decrease with OPA1 knockdown, suggesting that ROS might affect MyHC content by modulating OPA1 cleavage. In addition, hydroxytyrosol acetate (HT-AC), an important compound in virgin olive oil, could significantly prevent t-BHP-induced mitochondrial membrane potential and cell viability loss in myotubes. Specifically, HT-AC inhibited t-BHP-induced OPA1 cleavage and mitochondrial morphology changes, accompanied by improvement on mitochondrial oxygen consumption capacity, ATP productive potential and activities of mitochondrial complex I, II and V. Moreover, both t-BHP- and FCCP-induced MyHC decrease was sufficiently inhibited by HT-AC. Taken together, our data provide evidence indicating that mitochondrial dysfunction-associated OPA1 cleavage may contribute to muscle degeneration, and olive oil compounds could be effective nutrients for preventing the development of muscle disorders.

Zeaxanthin induces Nrf2-mediated phase II enzymes in protection of cell death.

Zeaxanthin (Zea) is a major carotenoid pigment contained in human retina, and its daily supplementation associated with lower risk of age-related macular degeneration. Despite known property of Zea as an antioxidant, its underlying molecular mechanisms of action remain poorly understood. In this study, we aim to study the regulation mechanism of Zea on phase II detoxification enzymes. In normal human retinal pigment epithelium cells, Zea promoted the nuclear translocation of NF-E2-related factor 2 (Nrf2) and induced mRNA and protein expression of phase II enzymes, the induction was suppressed by specific knockdown of Nrf2. Zea also effectively protected against tert-butyl hydroperoxide-induced mitochondrial dysfunction and apoptosis. Glutathione (GSH) as the most important antioxidant was also induced by Zea through Nrf2 activation in a time- and dose-dependent manner, whereas the protective effects of Zea were decimated by inhibition of GSH synthesis. Finally, Zea activated the PI3K/Akt and MAPK/ERK pathway, whereas only PI3K/Akt activation correlated with phase II enzymes induction and Zea protection. In further in vivo analyses, Zea showed effects of inducing phase II enzymes and increased GSH content, which contributed to the reduced lipid and protein peroxidation in the retina as well as the liver, heart, and serum of the Sprague-Dawley rats. For the first time, Zea is presented as a phase II enzymes inducer instead of being an antioxidant. By activating Nrf2-mediated phase II enzymes, Zea could enhance anti-oxidative capacity and prevent cell death both in vivo and in vitro.

Moderate NaFeEDTA and ferrous sulfate supplementation can improve both hematologic status and oxidative stress in anemic pregnant women.

Iron is important general well being, to prevent or treat anemia, and is a cofactor of many enzymes in the anti-oxidant process. Effect of sodium iron ethylenediaminetetraacetate (NaFeEDTA) and ferrous sulfate on iron bioavailability and oxidative stress in anemic pregnant women was evaluated. A 2-month randomized controlled trial was conducted on 153 anemic pregnant women, with 80 <= Hb <110 g/L. They were randomly allocated to three groups: group C (n=51) was the placebo control group, group I (n=51) was supplemented daily with 60 mg iron as ferrous sulfate, and group IE (n=51) with 60 mg iron as NaFeEDTA. Blood samples were collected before and at the end of the intervention for measurements of hematological indices and oxidative stress parameters. Considerable increases of hematologic indicators were observed: 20.5 and 21.8 g/L for Hb (both p values <0.001); 4.81 and 7.19 µmol/L for plasma iron (both p values <0.001), 2.63 and 8.99 µg /L for ferritin (both p values <0.05) in I and IE groups, respectively, compared with the control group. Glutathione peroxidase (GSH-Px) activities increased by 32.6 and 75.3 IU/ml, and malondialdehyde (MDA) levels decreased by 0.70 and 1.12 µmol/L in I and IE groups, compared with the C group (p values <0.05). Moreover, differences of plasma iron, ferritin and GSH-Px activity were 2.38 µmol/L, 6.36 µg /L and 42.7 IU/ml were also significantly greater in the IE group than in the I group. Moderate iron supplementation may be beneficial to improving iron deficiency and oxidative stress, and NaFeEDTA is better than ferrous sulfate.

A combination of iron and retinol supplementation benefits iron status, IL-2 level and lymphocyte proliferation in anemic pregnant women.

BACKGROUND: Iron and vitamin A deficiencies impact anemia and the immune system. OBJECTIVE: to investigate the effect of iron combined with retinol supplementation on iron status, IL-2 level and lymphocyte proliferation. METHODS: a double-blind randomized trial conducted over 2 months. We randomly allocated 186 anemic pregnant women with 80 ≤ Hb 0 < 110 g/L into four groups. Group I (n=47) was supplemented daily with 60 mg iron as ferrous sulfate, IF (n=46) with 60 mg iron and 0.4 mg folic acid, IR (n=46) with 60 mg iron, 2.0 mg retinol and 0.4 mg folic acid and C (n=47) was the placebo group,. RESULTS: after the 2 months trial, there were considerable increases of iron status in Hb, plasma iron and ferritin in the I, IF and IR groups compared with Group C. Increases in plasma iron and ferritin in the IR group were also significantly greater than in Groups I and IF. Compared with group C, increases of IL-2 levels were 119, 184 and 206 ng/L; and lymphocyte proliferation increased by 0.095, 0.112 and 0.219 in Groups I, IF and IR, respectively. Increases of IL-2 were 65.3 ng/L and 87.5 ng/L in Groups IF and IR, greater than in Group I (both p values <0.01); and lymphocyte proliferation in Group IR were 0.124 and 0.107, also greater than in Groups I and IF, respectively. CONCLUSION: iron combined retinol supplementation was more beneficial to improving iron status and lymphocyte proliferation during pregnancy than iron alone.

Retinol and riboflavin supplementation decreases the prevalence of anemia in Chinese pregnant women taking iron and folic Acid supplements.

In rural China, many pregnant women in their third trimester suffer from anemia (48%) and iron deficiency (ID; 42%), often with coexisting deficiencies of retinol and riboflavin. We investigated the effect of retinol and riboflavin supplementation in addition to iron plus folic acid on anemia and subjective well-being in pregnant women. The study was a 2-mo, double-blind, randomized trial. Subjects (n = 366) with anemia [hemoglobin (Hb)

First Report of 'Candidatus Liberibacter asiaticus' from Atalantia buxifolia in Guangdong, China.

Atalantia buxifolia (Poir.) Oliv., synonym Severinia buxifolia (Poir.) Ten. as commonly found in literature, is a common landscape plant and a popular Chinese medicinal herb known as Jiubingle or Dongfengjie. It remains unclear if this rutaceous plant could host 'Candidatus Liberibacter asiaticus', the pathogen of citrus Huanglongbing (HLB) in Guangdong, P. R. China. This information is important for HLB control in citrus because infected A. buxifolia could serve as a source of inoculum. In August of 1994, three A. buxifolia plants adjacent to a citrus experimental orchard of the South China Agricultural University at Guangzhou were found showing leaf mottle/yellowing symptoms. Two buds from each plant were grafted onto three mandarin trees (Citrus reticulata cv. Pongan) in a psyllid-proof screenhouse for indexing. By October of 1995, typical leaf mottle symptoms were observed in all three grafted trees compared with a healthy control. In March of 1996, one of the A. buxifolia plants was transferred to a screenhouse and has been maintained there. The leaf mottle/yellowing symptoms persisted but did not significantly affect plant growth. DNA was extracted from leaf samples in October 2006 by using the CTAB (cetyltrimethylammoniumbromide) method and assayed by nested-PCR using the general bacterial 16S rDNA primer set fDl/rD1 as the first round of amplification and primer set OI1/OI2c as second round amplification (1,3). After agarose gel electrophoresis and staining with ethidium bromide, an approximate 1.1-kb DNA band was detected in symptomatic samples but not healthy leaf samples of A. buxifolia and C. reticulata. XbaI digestion of the amplicons yielded approximate 500- and 600-bp fragments, characteristic of 'Ca. L. asiaticus'. Similarly, a standard PCR with primer set A5/J2 (3) yielded an approximate 700-bp DNA band characteristic of 'Ca. L. asiaticus' from symptomatic samples only. To our knowledge, this is the first report of graft transmission and PCR detection of 'Ca. L. asiaticus' from A. buxifolia in Guangdong, P. R. China. This work also confirms the findings from Taiwan (2) that A. buxifolia could serve as a source of 'Ca. L. asiaticus'. References: (1) X. Deng et al. Online publication. doi:10.1094/PHP-2007-0419-01-BR. Plant Health Progress, 2007. (2) T.-H. Hung et al. Eur. J. Plant Pathol. 107:183, 2001. (3) S. Jagoueix et al. Mol. Cell. Probes 10:43, 1996.

Effects of electro-acupuncture on the expression of c-jun and c-fos in spared dorsal root ganglion and associated spinal laminae following removal of adjacent dorsal root ganglia in cats.

This study evaluated the plastic changes of c-jun and c-fos in the right sixth lumbar dorsal root ganglion (L6 DRG), Rexed's lamina II in representative spinal segments L3, L5, and L6 and in the nucleus dorsalis (ND) at L3 segments after electro-acupuncture (EA) in cats subjected to removal of L1-L5 and L7-S2 DRG. Following dorsal root ganglionectomy, there was a significant increase in the density of c-jun immunoreactivity in the neurons and glia in spinal lamina II and in the ND; there was also marked elevation in the expression of c-fos in ND. In both cases there was no change in the c-jun and c-fos immunoreactivity in the DRG. After EA in the operated animals, there was an up-regulation in the expression of c-jun in the L6 DRG and the associated spinal lamina II; however, increased c-fos expression was detected only in the L6 DRG. Western blot and RT-PCR were also performed to quantitatively explore the mRNA and protein expression changes in the spinal dorsal horn and associated DRG. Following partial deafferentation, there was a significant increase in the protein level of both c-jun and c-fos in the dorsal horn, while, in both cases there was no change in c-jun and c-fos protein and mRNA in the DRG. After EA in the operated animals, both c-jun protein and its mRNA in the L6 DRG as well as the associated dorsal horn of L6 spinal segment were upregulated, but increased c-fos protein and its mRNA was observed only in the L6 DRG. These findings suggested that c-jun and c-fos might be related to the acupuncture promoted spinal cord plasticity as reported previously.

Effects of elevated carbon dioxide concentration on growth and N2 fixation of young Robinia pseudoacacia.

Effects of elevated CO2 concentration ([CO2]) on carbon (C) and nitrogen (N) uptake and N source partitioning (N2 fixation versus mineral soil N uptake) of 1-year-old Robinia pseudoacacia were determined in a dual 13C and 15N continuous labeling experiment. Seedlings were grown for 16 weeks in ambient (350 ppm) or elevated [CO2] (700 ppm) with 15NH4 15NO3 as the only mineral nitrogen source. Elevated [CO2] increased the fraction of new C in total C, but it did not alter C partitioning among plant compartments. Elevated [CO2] also increased the fraction of new N in total N and this was coupled with a shift in N source partitioning toward N2 fixation. Soil N uptake was unaffected by elevated [CO2], whereas N2 fixation was markedly increased by the elevated [CO2] treatment, mainly because of increased specific fixation (mg N mg(-1) nodule). As a result of increased N2 fixation, the C/N ratio of tree biomass tended to decrease in the elevated [CO2] treatment. Partitioning of N uptake among plant compartments was unaffected by elevated [CO2]. Total dry mass of root nodules doubled in response to elevated [CO2], but this effect was not significant because of the great variability of root nodule formation. Our results show that, in the N2-fixing R. pseudoacacia, increased C uptake in response to increased [CO2] is matched by increased N2 fixation, indicating that enhanced growth in elevated [CO2] might not be restricted by N limitations.

On the nature of conformational openings: native and unfolded-state hydrogen and thiol-disulfide exchange studies of ferric aquomyoglobin.

Native-state amide hydrogen exchange (HX) of proteins in the presence of denaturant has provided valuable details on the structures of equilibrium folding intermediates. Here, we extend HX theory to model thiol group exchange (SX) in single cysteine-containing variants of sperm whale ferric aquomyoglobin. SX is complementary to HX in that it monitors conformational opening events that expose side-chains, rather than the main chain, to solvent. A simple two-process model, consisting of EX2-limited local structural fluctuations and EX1-limited global unfolding, adequately accounts for all HX data. SX is described by the same model except at very low denaturant concentrations and when the bulky labeling reagent 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) is used. Under these conditions SX can occur by a novel denaturant-dependent process. This anomalous behavior is not observed when the smaller labeling reagent methyl methanethiosulfonate is employed, suggesting that it reflects a denaturant-induced increase in the amplitudes of local structural fluctuations. It also is not seen in heme-free apomyoglobin, which may indicate that local openings are sufficiently large in the absence of denaturant to allow DTNB unhindered access. Differences in SX kinetics obtained using the two labeling reagents provide estimates of the sizes of local opening reactions at different sites in the protein. At all sequence positions examined except for position 73, the same opening event appears to facilitate exchange of both backbone amide and side-chain thiol groups. The C73 thiol group is exposed by a low-energy fluctuation that does not expose its amide group to exchange.

Central melanocortin receptors regulate insulin action.

Energy balance and insulin action are tightly coregulated. Leptin regulates energy intake and expenditure partly by modulation of the melanocortin pathway in the hypothalamus. Here we demonstrate potent effects of the melanocortin pathway on insulin action and body distribution of adiposity. Conscious rats received week-long infusions of either a melanocortin receptor agonist, alpha-melanocyte-stimulating hormone (alpha-MSH), or antagonist, SHU9119, in the third cerebral ventricle while food intake was maintained constant in each group. alpha-MSH decreased intra-abdominal fat and markedly enhanced the actions of insulin on both glucose uptake and production, while SHU9119 exerted opposite effects. Our findings elucidate a neuroendocrine network that is likely to play a central role in the coupling of energy intake and insulin action.

Comparison of efficacy and side effects of combination therapy of angiotensin-converting enzyme inhibitor (benazepril) with calcium antagonist (either nifedipine or amlodipine) versus high-dose calcium antagonist monotherapy for systemic hypertension.

The present 2 multicenter studies were designed to evaluate whether patients with essential hypertension derived equal benefits from use of combination therapy with a calcium antagonist and angiotensin-converting enzyme (ACE) inhibitor as from doubling the dose of the calcium antagonist. After a 2-week washout and a 2-week single-blind placebo run-in period, a total of 1,390 patients were treated with either nifedipine 30 mg (study 1) or amlodipine 5 mg (study 2) once daily for 4 weeks. The 1,079 patients whose diastolic blood pressure remained between 95 and 115 mm Hg were randomized to 8 weeks of double-blind therapy with amlodipine 5 mg/benazepril 10 mg, amlodipine 5 mg/ benazepril 20 mg, nifedipine 30 mg or nifedipine 60 mg (study 1), and amlodipine 5 mg/benazepril 10 mg, amlodipine 5 mg/benazepril 20 mg, amlodipine 5 mg or amlodipine 10 mg (study 2). Both doses of the calcium antagonist/ACE inhibitor combination therapy lowered diastolic pressure as much as the high dose and significantly better than the lower dose of calcium antagonist monotherapy (with either nifedipine or amlodipine). However, 15% of patients in the nifedipine high-dose monotherapy group and 24% in the amlodipine high-dose monotherapy group presented with some form of edema. In contrast, the incidence of edema was similar for patients treated with both combination therapy and low-dose calcium antagonists. Thus, combination therapy with a calcium antagonist and an ACE inhibitor provides blood pressure control equal to that of high-dose calcium antagonist monotherapy but with significantly fewer dose-dependent adverse experiences such as vasodilatory edema. Inc.

[Effects of salvianolic acid B on beta-amyloid peptide neurotoxicity of primary cultured fetal rat cortical neurons].

AIM: To study the roles of nitric oxide (NO) and nitric oxide synthase (NOS) on the glutamate (Glu) and beta-amyloid peptide [beta-AP (1-40)] mediated neurotoxicity in primary cultured fetal rat cortical neuron and the neuroprotective effects of salvianolic acid B (Sal B) against the beta-AP (1-40) and its mechanism of action. METHODS: With application of specific agonist and antagonist of NOS, establishment of the sodium nitroprusside (SNP), Glu and beta-AP (1-40) neurotoxicity model, the cell viability, lactate dehydrogenase (LDH) efflux and NO release were detected by using morphological observation, MTT stain, spectrophotometric measurement and Griess method, respectively, in primary cultured fetal rat cortical neurons. RESULTS: Glu and beta-AP (1-40) were shown to increase the NO release of the neuron. Furthermore, nNOS was found to play an important role in the neurotoxicity of glutamate, iNOS may probably be involved in the neurotoxicity of beta-AP (1-40). Sal B (0.01, 0.10, 1.00 microgram.L(-1)) was shown to increase the cell viability, decrease the LDH release rate and inhibit NO release in a dose-dependent manner. CONCLUSION: These results suggest that the neurotoxicity of Glu and beta-AP(1-40) may be partly mediated through different types of NOS. Sal B was found to prevent the beta-AP(1-40) toxicity by directly or indirectly decreasing NO release.

Synthesis, bioactivity, and cloning of the L-type calcium channel blocker omega-conotoxin TxVII.

omega-Conotoxin TxVII is the first conotoxin reported to block L-type currents. In contrast to other omega-conotoxins, its sequence is characterized by net negative charge and high hydrophobicity, although it retains the omega-conotoxin cysteine framework. In order to obtain structural information and to supply material for further characterization of its biological function, we synthesized TxVII and determined its disulfide bond pairings. Because a linear precursor with free SH groups showed a strong tendency to aggregate and to polymerize, we examined many different conditions for air oxidation and concluded that a mixture of cationic buffer and hydrophobic solvent was the most effective for the folding of TxVII. Synthetic TxVII was shown to suppress the slowly inactivating voltage-dependent calcium current in cultured Lymnaea RPeD1 neurons and furthermore to suppress synaptic transmission between these neurons and their follower cells. In contrast, TxVII did not block calcium flux through L-type channels in PC12 cells, suggesting a phyletic or subtype specificity in this channel family. Disulfide bond pairings of TxVII and its isomers were determined by enzymatic fragmentation in combination with chemical synthesis, thus revealing that TxVII has the same disulfide bond pattern as other omega-conotoxins. Furthermore, the CD spectrum of TxVII is similar to those of omega-conotoxins MVIIA and MVIIC. The precursor sequence of TxVII was determined by cDNA cloning and shown to be closest to that of delta-conotoxin TxVIA, a sodium channel inactivation inhibitor. Thus TxVII conserves the structural fold of other omega-conotoxins, and the TxVIA/TxVII branch of this family reveals the versatility of its structural scaffold, allowing evolution of structurally related peptides to target different channels.