First detection of Candidatus Rickettsia tarasevichiae in Hyalomma marginatum ticks.

Ticks are important vectors of zoonotic diseases and play a major role in the circulation and transmission of many rickettsial species. The aim of this study was to investigate the carriage of Candidatus Rickettsia tarasevichiae (CRT) in a total of 1168 ticks collected in Inner Mongolia to elucidate the potential public health risk of this pathogen, provide a basis for infectious disease prevention, control and prediction and contribute diagnostic ideas for clinical diseases that present with fever in populations exposed to ticks. A total of four tick species, Haemaphysalis concinna (n = 21), Dermacentor nuttalli (n = 122), Hyalomma marginatum (n = 148), and Ixodes persulcatus (n = 877), were collected at nine sampling sites in Inner Mongolia, China, and identified by morphological and molecular biological methods. Reverse transcription PCR targeting the 16S ribosomal RNA (rrs), gltA, groEL, ompB and Sca4 genes was used to detect CRT DNA. Sequencing was used for pathogen species confirmation. The molecular epidemiological analysis showed that three species of ticks were infected with CRT, and the overall positive rate was as high as 42%. The positive rate of I. persulcatus collected in Hinggan League city was up to 96%, and that of I. persulcatus collected in Hulun Buir city was 50%. The pool positive rates of D. nuttalli and H. marginatum collected in Bayan Nur city and H. concinna collected in Hulun Buir city were 0%, 28% and 40%, respectively. This study revealed the high prevalence of CRT infection in ticks from Inner Mongolia and the first confirmation of CRT detected in H. marginatum in China. The wide host range and high infection rate in Inner Mongolia may dramatically increase the exposure of CRT to humans and other vertebrates. The role of H. marginatum in the transmission of rickettsiosis and its potential risk to public health should be further considered.

Microbial diversity of ticks and a novel typhus group Rickettsia species (Rickettsiales bacterium Ac37b) in Inner Mongolia, China.

Ticks can carry multiple pathogens, and Inner Mongolia's animal husbandry provides excellent environmental conditions for ticks. This study characterized the microbiome of ticks from different geographical locations in Inner Mongolia; 905 Dermacentor nuttalli and 36 Ixodes persulcatus were collected from sheep in three main pasture areas and from bushes within the forested area. Mixed DNA samples were prepared from three specimens from each region and tick species. Microbial diversity was analyzed by 16S rRNA sequencing, and α and ß diversity were determined. The predominant bacterial genera were Rickettsia (54.60%), including Rickettsiales bacterium Ac37b (19.33%) and other Rickettsia (35.27%), Arsenophonus (11.21%), Candidatus Lariskella (10.84%), and Acinetobacter (7.17%). Rickettsia bellii was identified in I. persulcatus, while Rickettsiales bacterium Ac37b was found in D. nuttalli from Ordos and Chifeng. Potential Rickettsia and Anaplasma coinfections were observed in the Ordos region. Tick microbial diversity analysis in Inner Mongolia suggests that sheep at the sampling sites were exposed to multiple pathogens.

Title: Diversité microbienne des tiques et nouvelle espèce de Rickettsia du groupe du typhus (bactérie Rickettsiales Ac37b) en Mongolie intérieure, Chine. Abstract: Les tiques peuvent être porteuses de plusieurs agents pathogènes et l'élevage en Mongolie intérieure offre d'excellentes conditions environnementales pour les tiques. Cette étude a caractérisé le microbiome des tiques de différentes zones géographiques de Mongolie intérieure; 905 Dermacentor nuttalli et 36 Ixodes persulcatus ont été collectés sur des moutons dans trois principales zones de pâturage et dans des buissons de la zone forestière. Des échantillons d'ADN mixtes ont été préparés à partir de trois spécimens de chaque région et espèce de tique. La diversité microbienne a été analysée par séquençage de l'ARNr 16S et la diversité α et ß a été déterminée. Les genres bactériens prédominants étaient les Rickettsia (54,60 %), dont la bactérie Rickettsiales Ac37b (19,33 %) et d'autres Rickettsia (35,27 %), Arsenophonus (11,21 %), Candidatus Lariskella (10,84 %) et Acinetobacter (7,17 %). Rickettsia bellii a été identifiée chez I. persulcatus, tandis que la bactérie Rickettsiales Ac37b a été trouvée chez D. nuttalli d'Ordos et Chifeng. Des co-infections potentielles à Rickettsia et Anaplasma ont été observées dans la région d'Ordos. L'analyse de la diversité microbienne des tiques en Mongolie intérieure montre que les moutons présents sur les sites d'échantillonnage sont exposés à plusieurs agents pathogènes.

Model construction and theoretical evaluation of the performance improvement of acetone-butanol-ethanol extractive fermentation by adding surfactant.

Severe butanol toxicity to the metabolism of solventogenic clostridia significantly impede the application of fermentative butanol as a biofuel. Liquid-liquid extraction is an efficient method to reduce the butanol toxicity by in-situ removing it in the extractant phase. Butanol mass transfer into extractant phase in static acetone-butanol-ethanol (ABE) extractive fermentation with biodiesel as the extractant could be enhanced by adding a tiny amount of surfactant such as tween-80. In the case of corn-based ABE extractive fermentation by Clostridium acetobutylicum ATCC 824 using biodiesel originated from waste cooking oil as extractant, addition of 0.14% (w/v) tween-80 could increase butanol production in biodiesel and total solvents production by 21% and 17%, respectively, compared to those of control under non-surfactant existence. Furthermore, a mathematical model was developed to elucidate the mechanism of enhanced ABE extractive fermentation performance. The results indicated that the mass transfer improvement was obtained by effectively altering the physical properties of the self-generated bubbles during ABE extractive fermentation, such as reducing bubble size and extending its retention time in extractant phase, etc. Overall, this study provided an efficient approach for enhancing biobutanol production by integration of bioprocess optimization and model interpretation.

Utilization of lignocellulosic biomass by glycerol organosolv pretreatment for biobutanol production integrated with bioconversion of residual glycerol into value-added products.

Glycerol organosolv pretreatment (GOP) is considered an efficient method to deconstruct lignocellulose for producing fermentable sugars. Herein, the liquid fraction containing glycerol after GOP was utilized for recycled pretreatment of corn stover (CS) for four cycles. Enzymatic yield of glucose after recycled pretreatment was enhanced by 2.4-3.5 folds compared with untreated CS. Meanwhile, residual glycerol was used as carbon source for cultivation of Pichia pastoris to obtain high cell-density, and a final titer of 1.3 g/L human lysozyme was produced by P. pastoris under low temperature methanol induction strategy. Additionally, the pretreated CS was mixed with cassava as fermentable substrates for butanol production by wild-type Clostridium acetobutylicum ATCC 824. Final butanol production of 13.9 g/L was obtained from mixed substrates (25%:75% of CS/cassava) at 10% solids loading by simultaneous saccharification and fermentation. Overall, integration of residual glycerol utilization and butanol production by microbial fermentation provided an efficient strategy for biorefinery.

Visual closed dumbbell-mediated isothermal amplification (CDA) for on-site detection of Rickettsia raoultii.

Spotted fever group (SFG) rickettsioses are important zoonoses, threatening human health seriously and gradually attracting more attention in the world. SFG rickettsiae are classified as neglected pathogens. If these pathogens are detected at all, they are usually recognized very late in the infection through indirect detection of specific antibodies. Previous studies have shown that Rickettsia raoultii (R. raoultii), a member of the SFG rickettsiae, occurs with increasing incidence in remote countries. Therefore, a rapid detection method for R. raoultii is in urgently need. In this study, a R. raoultii diagnosis method by closed dumbbell-mediated isothermal amplification (R-CDA) assay targeting a conserved sequence of the outer membrane protein A (OmpA) gene with high sensitivity and specificity was developed. This assay offered a rapid and simple method for on-site detection of R. raoultii. Firstly, four pairs of R-CDA primers were designed and the optimum primer set was selected to amplify target gene specifically and effectively. Then, a pair of outer primer was designed to accelerate the reaction based on the inner primers to establish the RO-CDA reaction. In addition, the results of real-time amplification curves, melting curves and end-point colorimetric judgements showed that the established visual RO-CDA reaction could accurately detect R. raoultii without cross-reaction with other closely related pathogens. Furthermore, the detection limit of visual RO-CDA assay was 10 copies/µL, which was feasible for on-site detection with merits of easy-operation, rapidity, high sensitivity, and specificity. In conclusion, the developed RO-CDA detection method could be helpful for pathogen screening and epidemic prevention at the point of care.

Identification and genetic diversity analysis of Rickettsia in Dermacentor nuttalli within inner Mongolia, China.

BACKGROUND: The genus Rickettsia contains the lineages spotted fever group (SFG), typhus group (TG), and transitional group (TRG). The spotted fever group Rickettsia (SFGR) is transmitted by ticks. The tick species Dermacentor nuttalli is considered the main vector carrying SFGR in Inner Mongolia. Studying the genetic diversity and population structure of Rickettsia is essential for developing effective control strategies and predicting evolutionary trends of Rickettsia. METHODS: In 2019 we collected 408 D. nuttalli in the Inner Mongolia Autonomous Region, detected the percentage of Rickettsia-positive specimens, and characterized the haplotypes. From the Rickettsia-positive ticks, the gltA and ompA genes were extracted, amplified, and sequenced. RESULTS: Ten haplotypes of the gltA gene and 22 haplotypes of the ompA gene were obtained. The phylogenetic analysis showed that the haplotypes G1-G7 and G9 of the gltA gene cluster with Rickettsia raoultii, while G8 and G10 cluster with Rickettsia sibirica. Haplotypes O1-O15, O18 and O20-O22 of the ompA gene cluster with R. raoultii, while O16 and O19 cluster with R. sibirica. The average haplotype diversity was 0.3 for gltA and 0.7 for ompA. The average nucleotide diversity was greater than 0.05. Neutrality tests were nonsignificant for Tajima's D results and Fu's Fs results. The fixation index values (FST) showed that the degree of genetic differentiation between most sampled populations was small (FST < 0.05), whereas some populations showed a medium (FST > 0.05) or large (FST > 0.15) degree of differentiation. Analysis of molecular variance (AMOVA) revealed that the variation within populations was greater than that between populations. The mismatch analysis of Rickettsia showed double peaks. CONCLUSIONS: We found two Rickettsia spp. (R. raoultii and R. sibirica). The high genetic disparity of Rickettsia allows for easy adaption to different environments. Genetic differentiation between populations is small, and Rickettsia populations do not show a geographically differentiated structure. The high rates of retention and infection of Rickettsia in D. nuttalli together with the animal husbandry exchange in Inner Mongolia gradually led to the harmonization of genetic characteristics of Rickettsia across various regions. Overall, the significant genetic diversity and geographical structure of Rickettsia in D. nuttalli are critical for SFGR control.

Mitochondrial Genome Architecture and Evolutionary Origin of the Yao Silkworm, a Living Fossil of the Domestic Silkworm Bombyx mori (Lepidoptera: Bombycidae).

The Yao silkworm is a unique silkworm resource producing yellow flat plate silk that has only been reared by the Baiku Yao ethnic group in Nandan County, Guangxi Province, China for a thousand years. Here, we report the mitochondrial genomes (mitogenomes) of five Yao silkworm strains and 10 local Guangxi strains of the domestic silkworm (Bombyx mori) L. (Lepidoptera: Bombycidae), and use the resulting mitogenomes and the available Bombyx mitogenomes to characterize their genome architecture and trace the evolutionary origin of the Yao silkworm. The five Yao silkworm mitogenomes exhibited genome architectures identical to typical set of 37 mitochondrial genes (13 protein-coding genes, 22 transfer RNAs, and two ribosomal RNAs) and a high level of genome sequence similarity with the domestic silkworm. Mitogenome-based phylogenetic reconstruction provided solid evidence that the Yao silkworm shares a common ancestor with the domestic silkworm. Sliding window analysis uncovered a distinct variation pattern in the mitogenome between the Yao silkworm and the other domestic silkworm strains. The phylogenetic analyses revealed a basal placement of the Yao silkworm among all available domestic silkworm strains, indicating that the Yao silkworm is an ancient population of the domestic silkworm. Our data indicated that the Yao silkworm (B. mori) is a lineage of the domestic silkworm, which for the first time provides insights into the origin of the Yao silkworm.

Integrating network pharmacology deciphers the action mechanism of Zuojin capsule in suppressing colorectal cancer.

BACKGROUND AND PURPOSE: Zuojin capsule (ZJC), a classical prescription, is outstanding in improving the conditions of patients with gastrointestinal diseases and colorectal cancer (CRC). Although ZJC has multi-ingredient and multi-target characteristics, its pharmacological effect on colorectal cancer and the underlying mechanism remain unclear. METHOD: Here, the activity of ZJC against CRC was evaluated by the experiments with CRC cells and HCT-116 xenografted mice. The key genes of CRC were obtained from the cancer genome atlas (TCGA). The genes potentially targeted by ZJC were collected from traditional Chinese medicine systems pharmacology (TCMSP) database. The underlying pathways related to selected targets were analyzed through gene ontology (GO) and pathway enrichment analyses. Western blot (WB), cellular thermal shift assay (CETSA), molecular docking and quantitative real-time PCR (QRT-PCR) were carried out to confirm the validity of the targets. RESULTS: In vitro and in vivo results indicated that ZJC may inhibit CRC cells and tumor growth. The network pharmacological analysis indicated that 22 compounds, 51 targets and 20 pathways were involved in the compound-target-pathway network. Our results confirmed that ZJC inhibited cycle progression, migration and induced apoptosis by targeting candidate genes (CDKN1A, Bcl2, E2F1, PRKCB, MYC, CDK2, and MMP9). We found that ZJC could directly change the protein level by regulating the protein stability and transcriptional activity of the target. CONCLUSIONS: In summary, combined network pharmacology and biological experiments proved that the main ingredients of ZJC such as quercetin, (R)-Canadine, palmatine, rutaecarpine, evodiamine, beta-sitosterol and berberine can target CDKN1A, Bcl2, E2F1, PRKCB, MYC, CDK2 and MMP9 to combat colorectal cancer. The results of this study provide a basic theory for the clinical trials of Zuojin Capsules against colorectal cancer.

Heat Shock Protein 70 Family in Response to Multiple Abiotic Stresses in the Silkworm.

The 70 kDa heat shock proteins play important roles in protecting organisms against environmental stresses, which are divided into stress-inducible forms (HSP70s) and heat shock cognates (HSC70s). In this study, heat shock protein 70 family was identified in the whole genome of the silkworm. Based on the known nomenclature and phylogenetic analysis, four HSP70s and five HSC70s were classified. Relatively, heat shock cognates were more conservative and were constitutively expressed in various tissues of the silkworm larvae. Under thermal (37 °C and 42 °C) and cold (2 °C) stresses, the expressions of HSP70-1, HSP70-2, and HSP70-3 were up-regulated, and the highest induction reached 4147.3, 607.1, and 1987.3 times, respectively. Interestingly, HSC70-1, HSC70-4, and HSC70-5 also showed slight induced expressions in the fat body and/or midgut under thermal stresses. In addition, the expression of HSP70-1 was induced by dichlorvos and phoxim insecticides, while most HSC70 genes were inhibited. The results suggested that stress-inducible forms play more important roles in adaptation to various stresses than HSC70s.

Genetic diversity analysis of Dermacentor nuttalli within Inner Mongolia, China.

BACKGROUND: Ticks (Arthropoda, Ixodida), after mosquitoes, are the second most prevalent vector of infectious diseases. They are responsible for spreading a multitude of pathogens and threatening the health and welfare of animals and human beings. However, given the history of tick-borne pathogen infections in the Inner Mongolia Autonomous Region of China, surprisingly, neither the genetic diversity nor the spatial distribution of haplotypes within ticks has been studied. METHODS: We characterized the haplotype distribution of Dermacentor nuttalli in four main pastoral areas of the Inner Mongolia Autonomous Region, by sampling 109 individuals (recovered from sheep) in April-August 2019. The 16S rRNA gene, cytochrome c oxidase subunit I (COI), and the internal transcribed spacer 2 region (ITS2) were amplified and sequenced from extracted DNA. RESULTS: Twenty-six haplotypes were identified using 16S rRNA sequences, 57 haplotypes were identified with COI sequences, and 75 haplotypes were identified with ITS2 sequences. Among the three genes, total haplotype diversity was greater than 0.7, while total nucleotide diversity was greater than 0.06. Neutrality tests revealed a significantly negative Tajima's D result, while Fu's Fs was not significantly positive. Fixation index values (FST) indicated that the degree of genetic differentiation among some sampled populations was small, while for others it was moderate. Analysis of molecular variance (AMOVA) revealed that the variation within populations was greater than that among populations. The mismatch analysis of D. nuttalli exhibited double peaks. CONCLUSION: The genetic diversity of D. nuttalli populations in our region can likely adapt to different geographical environments, thereby leading to genetic diversity, and creating genetic differentiation among different populations. However, genetic differentiation is cryptic and does not form a pedigree geographical structure.

Clematisguniuensis (Ranunculaceae), a new species from Eastern China.

Clematisguniuensis sp. nov., a new narrowly endemic species of Clematis, is described and illustrated from the Huangshan Mountains of Eastern China. A description of C.guniuensis is presented along with illustrations, photographs and diagnostic differences between the new species and its putative close allies.

The complete mitochondrial genome of Yao silkworm (Bombyx mori).

Here, we describe the first complete mitochondrial genome of Yao silkworm, a unique silkworm resource native at Guangxi, China. This circular molecule is 15,656 bp long and contains the typical set of 37 genes (13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes) and one non-coding A + T-rich region of 494 bp long. The genome organization and gene arrangement are identical to those observed in all available Bombyx mori strains. The phylogenetic tree inferred from Bayesian inference provides a molecular evidence that Yao silkworm belongs to the domestic silkworm (B. mori), rather than a novel silkworm species.

Small molecule CCR5 antagonists in clinical trials and their drug resistances:research advances / 国际药学研究杂志

C-C chemokine receptor 5 (CCR5), one of the major co-receptors of HIV-1, can mediate the fusion of HIV-1 to cell membranes. CCR5 antagonists can bind to CCR5 and cause conformational changes in CCR5, thus blocking HIV-1 infection. Several small molecule CCR5 antagonists with strong activity and good tolerance have been screened and entered the clinical trials. With the widespread use of CCR5 antagonists, drug resistance has gradually emerged. There are many reports about of drug-related failure in vivo and in vitro. Therefore, this review summarizes the mechanism of CCR5-mediated HIV-1 infection, the research progress in maraviroc and other CCR5 antagonists which have entered clinical trials and their drug resistance.

Impact of CACNA1C polymorphisms on antihypertensive efficacy of calcium channel blocker / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the relationship between genetic polymorphisms of CACNA1C that encoded the a1c subunit of the L-type calcium channel and the efficacy of calcium channel blocker (CCB, Nifedipine extended release tablet/20 mg/d) in essential hypertension (EH) patients of Han Chinese in Wenzhou.</p><p><b>METHODS</b>For the enrolled 103 EH patients, Multiplex Polymerase Chain Reaction (Multi-PCR) and matrix assisted laser desorption ionization time of flight MS (MLDI-TOF MS) were performed to detect their genotypes (rs216008, rs1051375, rs2299661, rs10848683, rs215976), blood pressure (BP) after CCB monotherapy was compared among patients with different genotypes.</p><p><b>RESULTS</b>(1) Blood pressure was significantly reduced in all patients post CCB (P < 0.05 vs. pre-CCB). (2) Diastolic blood pressure reduction was more significant in subjects with rs2299661 C/C genotype (wild genotype) than in subjects with rs2299661C/G and rs2299661G/G genotype (mutational genotype) [(12.46 ± 7.91) mm Hg (1 mm Hg = 0.133 kPa) vs. (7.22 ± 8.01) mm Hg and (5.93 ± 9.77) mm Hg, P < 0.05]. (3) Systolic blood pressure reduction was more significant in subjects with rs216008 C/C genotype (wild genotype) than in subjects with rs216008 C/T genotype (mutational genotype) [(20.60 ± 12.35) mm Hg vs. (13.62 ± 10.21) mm Hg, P < 0.05]. (4) Blood pressure reduction was similar between subjects with genotype of rs1051375, rs10848683 and rs215976.</p><p><b>CONCLUSION</b>EH patients with wild genotype of rs2299661 and rs216008 in CACNA1C are more likely to be responders of CCB monotherapy.</p>

Strong anodic near-infrared electrochemiluminescence from CdTe quantum dots at low oxidation potentials.

Anodic near-infrared electrochemiluminescence (ECL) from CdTe quantum dots was achieved at low potential on a glass carbon electrode and a strategy for greatly enhanced band-gap ECL was presented.

Sero-epidemiologic investigation on tick-borne diseases of humans and domestic animals in Zhejiang province / 中华流行病学杂志

Objective To investigate the seroprevalence of tick-borne diseases in humans and domestic animals from rural areas of Zhejiang province. Methods Anji county, Jindong district and Tiantai county were selected for samples collection according to their geographic locations and historical prevalence of tick-borne diseases. Blood samples of humans and domestic animals were collected in the three sites. An indirect immuno-fluorescent antibody test was used to determine the presence of IgG antibodies of Rickettsiae heilongjiangii, Orientia tsutsugamushi, R. typhi, Anaplasma phagocytos, Ehrlichia chaffeensis, Bartonella, R. hainan and Coxiella burnetii in these samples.Results Six hundred and eighty-three blood samples including 579 from humans and 104 from domestic animals(53 from cattles and 51 from sheep)were collected from the three sites. Antibody positive rates of Orientia tsutsugamushi, R. typhi, Ehrlichia chaffeensis and Coxiella burnetii were significantly different between these sites. IgG from all the 8 pathogens were detected in samples from humans. It was found that the sero-prevalence rates of R. typhi, Bartonella and C. burnetii(20.7%,10.9%, 5.5%)of adults were higher than those of other Rickettsiae under investigation. The seroprevalence of R. typhi increased along with age. IgG from the 7 pathogens were detected in samples from domestic animals except for Anaplasma phagocytos. The sero-prevalence rates of R. typhi, Bartonella and R. hainan(69.2%, 51.0%, 22.1%)of adults were higher than those of other Rickettsiae investigated. Conclusion Tick-borne diseases did spread widely in humans and domestic animals from different rural areas of Zhejiang province. The sero-prevalence rates of R. typhi,B. henselae, R. hainan and C. burnetii were higher than that from other pathogens.

Job stress, gene polymorphism of beta2-AR, and prevalence of hypertension.

OBJECTIVE: To study the interactive effect of job stress and genetic susceptibility (or gene polymorphism) on hypertension. METHODS: A cross-sectional epidemiological study was conducted in 452 workers from a thermal power plant in China. Extrinsic effort, occupational reward, and over-commitment were measured. Hypertensive patients were defined by three phases of screening, reexamination, and final diagnosis. beta2-AR genotypes and allele frequencies at amino acid positions 16 (beta2-AR-16: Arg-->Gly) and 27 (beta2-AR-27: Gln-->Glu) were identified by PCR-RFLP. RESULTS: Job stress was related with the prevalence of hypertension in males (P < 0.05), whereas no significant relationship was found in females (P > 0.05). Differences in genotypes and allele frequencies of the beta2-AR-16 were statistically significant between the hypertension and control groups (P < 0.05), whereas those of beta2-AR-27 were not (P > 0.05). The prevalence of hypertension was higher in individuals carrying Gly16 allele than in those carrying Arg16 allele of the high job stress group (P < 0.01 or 0.05). CONCLUSION: High job stress and polymorphism of beta2-AR-16 have an interactive effect on the prevalence of hypertension in male workers.

Job stress, gene polymorphism of beta2-AR, and prevalence of hypertension / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the interactive effect of job stress and genetic susceptibility (or gene polymorphism) on hypertension.</p><p><b>METHODS</b>A cross-sectional epidemiological study was conducted in 452 workers from a thermal power plant in China. Extrinsic effort, occupational reward, and over-commitment were measured. Hypertensive patients were defined by three phases of screening, reexamination, and final diagnosis. beta2-AR genotypes and allele frequencies at amino acid positions 16 (beta2-AR-16: Arg-->Gly) and 27 (beta2-AR-27: Gln-->Glu) were identified by PCR-RFLP.</p><p><b>RESULTS</b>Job stress was related with the prevalence of hypertension in males (P < 0.05), whereas no significant relationship was found in females (P > 0.05). Differences in genotypes and allele frequencies of the beta2-AR-16 were statistically significant between the hypertension and control groups (P < 0.05), whereas those of beta2-AR-27 were not (P > 0.05). The prevalence of hypertension was higher in individuals carrying Gly16 allele than in those carrying Arg16 allele of the high job stress group (P < 0.01 or 0.05).</p><p><b>CONCLUSION</b>High job stress and polymorphism of beta2-AR-16 have an interactive effect on the prevalence of hypertension in male workers.</p>

Electrochemiluminescence of luminol in alkaline solution at a paraffin-impregnated graphite electrode.

The behavior of luminol electrochemiluminescence (ECL) at a paraffin-impregnated graphite electrode (PIGE) at different applied potentials was studied. Five ECL peaks were observed at 0.31, 0.59, 1.09, 1.54, and -0.58 V versus SCE, respectively, being related to potential scan direction and ranges, N2, O2, pH of the solution, and KCl concentration. The emission spectra of various ECL peaks at different potentials showed that all ECL peaks were initiated by luminol reactions. X-ray diffraction demonstrated that a simple mixture was formed between graphite and paraffin. The fluorescence spectra on the surface of the PIGE suggested that certain groups on the graphite were oxidized when the positive potential was applied to the electrode. In the presence of O2, three main ECL peaks were obtained in 0.1 mol/L KCl at pH 12.2. The ECL peak at 0.59 V with a shoulder is likely due to the reaction of luminol radicals with O2 and further electrooxidation of luminol radicals. The ECL peak at 1.54 V was suggested to be due to the electrooxidation of OH- to HO2- at higher potential and then to O2-, which reacted with luminol to produce light emission. Moreover, the oxygen-containing functional groups formed by the oxidation of the surface of the graphite electrode might enhance the ECL. At -0.58 V, the dissolved oxygen in solution was reduced to HO2-, resulting in light emission. At a potential higher than 1.64 V, ClO- was formed, leading to a broad emission wave and enhancement of the ECL peak at -0.58 V upon the reversal scan. Under nitrogen atmosphere, an ECL peak appeared at 1.09 V. At this potential, OH- was oxidized to O2, followed by the reaction with luminol to generate light emission. At pH 13.2 or 0.5 mol/L KCl, the shoulder of the ECL peak at 0.59 V became an ECL peak at 0.31 V. The conversion of luminol radicals into excited 3-aminophthalate may undergo two routes. Under these conditions, two routes might proceed at a different rate to form another ECL peak. It is concluded that luminol ECL could be readily excited by various oxygen-containing species electrogenerated at different applied potentials. Three strong ECL peaks obtained at different potentials on the PIGE might be of a potential to improve analytical selectivity and sensitivity for the detection of some analytes.

Biochemical characterization of two mutants of human pyruvate dehydrogenase, F205L and T231A of the E1alpha subunit.

Mutations in the E1alpha subunit of the pyruvate dehydrogenase multienzyme complex may result in congenital lactic acidosis, but little is known about the consequences of these mutations at the enzymatic level. Here we characterize two mutants (F205L and T231A) of human pyruvate dehydrogenase in vitro, using the enzyme expressed in Escherichia coli. Wild-type and mutant proteins were purified successfully and their kinetic parameters were measured. F205L shows impaired binding of the thiamin diphosphate cofactor, which may explain why patients carrying this mutation respond to high-dose vitamin B1 therapy. T231A has very low activity and a greatly elevated Km for pyruvate, and this combination of effects would be expected to result in severe lactic acidosis. The results lead to a better understanding of the consequences of these mutations on the functional and structural properties of the enzyme, which may lead to improved therapies for patients carrying these mutations.