A new expression vector for production of enzymes in the yeast Saccharomyces (Lachancea) kluyveri

We overexpressed and purified enzymes involved in the pyrimidine catabolic pathway in the yeast Saccharomyces (Lachancea) kluyveri. A new vector was therefore designed, providing the first specific expression system in Saccharomyces kluyveri. The URC1 gene was overexpressed and a soluble protein obtained and successfully purified using the C-terminally added His-tag. Our system will be used for further studies of the structure and function of the enzymes belonging to the URC pyrimidine degradation pathway.

Thermogravimetric investigation on co-combustion characteristics of tobacco residue and high-ash anthracite coal

The thermal behavior of high-ash anthracite coal, tobacco residue and their blends during combustion processes was investigated by means of thermogravimetric analysis (20 K min(-1), ranging from ambient temperature to 1273 K). Effects of the mixed proportion between coal and tobacco residue on the combustion process, ignition and burnout characteristics were also studied. The results indicated that the combustion of tobacco residue was controlled by the emission of volatile matter; the regions were more complex for tobacco residue (four peaks) than for coal (two peaks). Also, the blends had integrative thermal profiles that reflected both tobacco residue and coal. The incorporation of tobacco residue could improve the combustion characteristics of high-ash anthracite coal, especially the ignition and burnout characteristics comparing with the separate burning of tobacco residue and coal. It was feasible to use the co-combustion of tobacco residue and high-ash anthracite coal as fuel.

Effects of transportation on expression of Hsp90, Hsp70, Hsp27 and αB-crystallin in the pig stomach

Twenty pigs were randomly divided into four groups based on the amount of time spent in transport (zero, one, two or four hours). Pathological examination of all transported pigs showed that exfoliation of chief cells from the gastric surface occurred in pigs during transportation. These results imply that integrity of the gastric mucosa was compromised by damage occurring during the four-hour transportation, despite the fact that gastric ulcers were not present. Levels of Hsp90 expression in stomach tissues were significantly decreased (P<0.01) after two-hour transportation, but Hsp70 levels increased significantly (P<0.05) after one, two and four hours of transportation. Hsp27 levels remained relatively stable independent of the length of transport. Levels of αB-crystallin expression in the stomach were significantly increased (P<0.05) after four hours of transportation. Variations in Hsp90, Hsp70, Hsp27 and αB-crystallin levels suggest that distinct protective functions are modulated by different Hsps in stomach tissues during transportation. Alterations in Hsp70 and αB-crystallin expression appear to be associated with protective functions, as no apparent gastric ulcers were present in pigs that underwent four hours of transportation. Levels of heat shock transcription factor-1, which regulate the expression of Hsps, remained relatively stable independent of the transportation period.

Search for live attenuated vaccine candidate against edwardsiellosis by mutating virulence-related genes of fish pathogen Edwardsiella tarda

AIMS

The aims of this study were to construct and evaluate the live attenuated vaccine against edwardsiellosis on zebra fish model.

METHODS AND RESULTS

In this study, the deletion mutant of aroC gene for the biosynthesis of chorismic acid in Edwardsiella tarda EIB202 was firstly constructed by allelic exchange strategy. According to the genome information, 19 double mutants and one multiple mutant were successively constructed by deleting virulence-associated genes based on the ΔaroC mutant. Zebra fish model was used to assay the virulence of the mutants by intramuscular (i.m.) injection. Fourteen mutants were significantly attenuated with accumulated mortality ranged from 0 to 63% (P<0.05). The zebra fish vaccinated with ΔaroC, ΔaroCΔesrC, ΔaroCΔslyA and ΔaroCΔeseBCDΔesaC via i.m. injection showed ideal protection, resulting in relative per cent survival (RPS) of 68.3, 71.3, 80.1 and 81% against subsequent challenge with the wild-type Edw. tarda EIB202.

CONCLUSIONS

ΔaroCΔeseBCDΔesaC behaved a low virulence and the highest RPS on zebra fish model. When the zebra fish were vaccinated with ΔaroCΔeseBCDΔesaC via injection, the expression of immune-related factors including IgM and MHC II was up-regulated.

SIGNIFICANCE AND IMPACT

The mutant ΔaroCΔeseBCDΔesaC might serve as an effective live attenuated vaccine against edwardsiellosis.

Association of SPINK5 gene polymorphisms with atopic dermatitis in Northeast China

BACKGROUND

Defect in the SPINK5 gene is known to be implicated in Netherton syndrome (NS), and has been suggested to be a locus predisposing to atopy in general. Coding polymorphisms in SPINK5 exons 13, 14 and 26 have been reported to be associated with atopic dermatitis (AD), asthma and high level of IgE.

OBJECTIVES

To examine whether the SPINK5 gene polymorphisms are associated with AD in Northeast China, and to assess how variants influence selected phenotypic traits.

METHODS

A case-control study was conducted on four non-synonymous polymorphisms in the coding region of SPINK5 in AD and controls. The SPINK5 gene polymorphisms were analyzed using the PCR and RFLP methods.

RESULTS

For the four non-synonymous SNPs, A1103G(Asn368Ser), G1156A(Asp386Asn), G1258A(Glu420Lys), G2475T(Glu825Asp) in SPINK5, the allelic frequencies in the AD cohort were 0.55 for 1103G, 0.57 for 1156A, 0.54for 1258A, 0.62 for 2475T, consistent with those already published in the original British and Japanese cohorts. The T allele of SNP 2475G > T was found to be significantly associated with AD. There were significant differences in genotype frequencies for G1258A(Glu420Lys) and G2475T(Glu825Asp) but not for A1103G(Asn368Ser) and G1156A(Asp386Asn). Genotypes GA(420Glu/Lys), TT (2475Asp/Asp) and GT(2475Glu/Asp) were significantly more frequent in AD. However, the SPINK5 gene polymorphisms was found not to be associated with AD in regard to either serum IgE levels, concurrent allergic asthma or early onset of AD.

CONCLUSIONS

Our study confirms the association between SPINK5 and AD.

Influencing factors on the size uniformity of self-assembled SiGe quantum rings grown by molecular beam epitaxy

The size uniformity of self-assembled SiGe quantum rings, which are formed by capping SiGe quantum dots with a thin Si layer, is found to be greatly influenced by the growth temperature and the areal density of SiGe quantum dots. Higher growth temperature benefits the size uniformity of quantum dots, but results in low Ge concentration as well as asymmetric Ge distribution in the dots, which induces the subsequently formed quantum rings to be asymmetric in shape or even broken somewhere in the ridge of rings. Low growth temperature degrades the size uniformity of quantum dots, and thus that of quantum rings. A high areal density results in the expansion and coalescence of neighboring quantum dots to form a chain, rather than quantum rings. Uniform quantum rings with a size dispersion of 4.6% and an areal density of 7.8×10(8) cm(-2) are obtained at the optimized growth temperature of 640°C.

A two-stage inexact joint-probabilistic programming method for air quality management under uncertainty

A two-stage inexact joint-probabilistic programming (TIJP) method is developed for planning a regional air quality management system with multiple pollutants and multiple sources. The TIJP method incorporates the techniques of two-stage stochastic programming, joint-probabilistic constraint programming and interval mathematical programming, where uncertainties expressed as probability distributions and interval values can be addressed. Moreover, it can not only examine the risk of violating joint-probability constraints, but also account for economic penalties as corrective measures against any infeasibility. The developed TIJP method is applied to a case study of a regional air pollution control problem, where the air quality index (AQI) is introduced for evaluation of the integrated air quality management system associated with multiple pollutants. The joint-probability exists in the environmental constraints for AQI, such that individual probabilistic constraints for each pollutant can be efficiently incorporated within the TIJP model. The results indicate that useful solutions for air quality management practices have been generated; they can help decision makers to identify desired pollution abatement strategies with minimized system cost and maximized environmental efficiency.

Molecular characterization of erm(B)- and mef(E)-mediated erythromycin-resistant Streptococcus pneumoniae in China and complete DNA sequence of Tn2010

AIMS

To characterize the erm(B)- and mef(E)-mediated erythromycin-resistant Streptococcus pneumoniae clinical isolates obtained from ten hospitals located different cities in China.

METHODS AND RESULTS

Totally 83 S. pneumoniae were collected, and eighteen representative strains of 66 strains that exhibited erythromycin resistance were used for further characterization by antibiograms, serotyping, PFGE, MLST, DNA sequencing of the macrolide-resistance elements and mapping of the elements on the chromosome. Twelve isolates showed a high-level resistance to erythromycin, and six other isolates showed a low-level resistance to erythromycin. Thirteen isolates harboured a Tn2010 transposon (26·4 kbp) encoding the erm(B), tet(M) and mef(E) genes and were classified into three types by Tn2010 structures. The remaining five isolates harboured a Tn6002 transposon (20·9 kbp) encoding the erm(B) and tet(M) genes and were classified into three types by Tn6002 locations on the chromosome. Three of the Tn6002 elements were located within the Tn5252-like element, implying that these composed a large mobile element. The MLST analyses showed that several clones had been disseminated and that the CC271 strains carrying the Tn2010 element expressing the high-level resistance to erythromycin were predominant in China. Four new MLST strains, which were designated as ST3262, ST3263, ST3397 and ST3398 were also identified.

CONCLUSIONS

The erythromycin resistance determinant of S.pneumoniae that had been isolated in China was located in Tn2010 or the Tn6002 element and several clones had been disseminated, and the CC271 strains carrying the Tn2010 element expressing the high-level resistance to erythromycin were predominant in China.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first molecular analysis of erythromycin-resistant Streptococcus pneumoniae clinical isolates in China, and the first report of the complete nucleotide sequence of Tn2010 (26,390 bp).

Mechanism of St. John's wort extract (STW3-VI) during chronic restraint stress is mediated by the interrelationship of the immune, oxidative defense, and neuroendocrine system

Chronic stress is a contributing risk factor for the development of psychiatric illnesses such as anxiety and depression disorders. The aim of the present study was to evaluate the mechanisms of action of the standardized St. John's wort extract (STW3-VI; SJW) in a chronic restraint stress model. Markers of antioxidant capacity such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) in the hippocampus and hypothalamus, and plasma levels of ACTH and corticosterone as well as the inflammatory markers IL-6 and TNF-alpha were determined in rats exposed to chronic restraint stress for 21 consecutive days. In addition, total body and relative organ weights as well as behavioral changes in the open field test were evaluated on the last day. The results show that stressed animals decreased in open field activity compared to unstressed animals, which could be reversed by fluoxetine (10mg/kg, p.o.) and SJW (125-750mg/kg, p.o.) treatment. In addition, chronic restraint stress significantly decreased thymus and spleen indices in the stressed control group. However, treating stressed rats with fluoxetine or STW3-VI produced a significant and dose dependent increase in both thymus and spleen indices compared to stressed controls. Additionally, SJW and fluoxetine significantly reduced stress-induced increases in plasma ACTH and corticosterone levels. Furthermore, the administration of SJW significantly reduced the stress-induced increase in TNF-alpha levels. Our data provide new evidence for the hypothesis that the mechanism of action of STW3-VI is mediated by the interrelationship between the immune, oxidative defense and neuroendocrine system.

Immunosuppressive effects of emodin: an in vivo and in vitro study

OBJECTIVE

We sought to investigate the immunosuppressive effects of emodin and its potential in vivo and in vitro mechanisms.

METHODS

In vitro immunosuppressive effects of emodin were analyzed by its ability to suppress the response of human peripheral blood mononuclear cells to phytohemagglutinin (PHA) and to mixed lymphocyte culture (MLC). We examined changes in interleukin (IL)-2 and IL-4 in within MLC supernates. The in vivo immunosuppressive effects of emodin were analyzed using a skin transplantation model in mice. We also investigated the mean survival time (MST) and plasma IL-2 levels.

RESULTS

In vitro experiments: Responses of mononuclear cells to PHA and MLC were suppressed by emodin treatment. Decreased production of IL-2 along with promoted secretion of IL-4 was also observed by emodin treatment during MLC. In vivo experiments: The emodin-treated group showed prolonged MST of skin grafts and decreased serum IL-2 production.

CONCLUSIONS

Emodin showed immunosuppressive activities both in vivo and in vitro. The potential immunosuppressive mechanism of emodin's may be suppression of lymphocyte proliferation and influences on cytokines.

The role of liver transplantation in the treatment of hepatic myelopathy: case report with review of the literature

BACKGROUND AND AIMS

Hepatic myelopathy (HM) is a rare neurological complication of chronic liver disease, causing progressive spastic paraparesis. Unlike hepatic encephalopathy, the conservative treatment of HM is usually considered inefficient. Although some scattered case studies have reported that the clinical symptoms and signs of patients with HM were improved after orthotopic liver transplantation (OLT), there have also been cases of failure. The aim of this study was to identify the role of OLT in the treatment of HM.

PATIENTS AND METHODS

We present two patients, who underwent OLT at the early stage after progressive HM had been diagnosed, gaining definite improvement of their neurological status within a relatively short time. In addition, we review all five similar cases that have hitherto been reported in English literature.

RESULTS

The clinical symptoms and signs of HM improved to variable degrees after OLT in most cases except one with a long HM history. The degree of improvement correlated with the time interval between the onset of the first symptoms of HM and OLT.

CONCLUSIONS

OLT represents an effective therapeutic option for HM. The duration of clinical manifestations of HM before OLT may be the main factor affecting the therapeutic outcome.

Sibling separation and psychological problems of double AIDS orphans in rural China - a comparison analysis

OBJECTIVE

We investigated the psychological impact of sibling separation among children who lost both of their parents to AIDS and were placed in group care or kinship care settings in rural China.

METHODS

Comparative analysis of cross-sectional survey data among 155 children among whom 96 experienced sibling separation. Trauma symptoms (Anxiety, Depression, Anger, Post-traumatic stress, Dissociation, Sexual concerns) were compared between the AIDS orphans who experienced sibling separation and those who did not using analysis of variance and multivariate analysis of covariance.

RESULTS

Among the participants (47.7% girls) with an average age of 12.4 years, univariate and multivariate analyses showed that separation from siblings was associated with significantly higher scores in anxiety, depression, anger and dissociation before or after controlling for gender, age, care arrangement, number of household replacement, trusting relationship with the current caregivers and perceived quality of current living condition. Sibling separation among orphans was not associated with level of post-traumatic stress and sexual concerns.

CONCLUSION

AIDS orphans separated from their siblings suffered from increased psychological distress compared with those who remained with their siblings. The data in the current study suggest that care arrangement for AIDS orphan should include accommodating the siblings together or providing them with opportunities for frequent contact and/or communication with each other. Appropriate psychological counselling should be given to those orphans experiencing sibling separation.

Hepatic and renal artery rupture due to Aspergillus and Mucor mixed infection after combined liver and kidney transplantation: a case report

Fungal infection is a major cause of death in patients who undergo organ transplantation. The incidence of Aspergillus or Mucor infection is low compared with Candida species. We report a case in which Aspergillus and Mucor infected both the hepatic and renal arteries, leading the 2 arteries to rupture at the same time. The patient died 4 days after the second operation. We review the recent literature about this topic and explore the possible route of transmission in our patient. We also discuss the prophylactic methods for Aspergillus and Mucor infections.

Novel magnetic rings for rapid vascular reconstruction in canine liver transplantation model

OBJECTIVE

Magnetic rings were used for rapid vascular reconstruction in a canine liver transplantation model.

MATERIALS AND METHODS

Thirty-two adult mongrel dogs weighing 13 to 16 kg were randomly selected as donors or recipients of transplantations. The recipients were randomly divided into two groups: group A (n = 10) had magnetic rings used for vascular reconstruction without venovenous bypass; group B (n = 6) had vascular reconstruction performed by continuous suturing with splenojugular venovenous bypass.

RESULTS

In group A, the entire operative period was 3.24 +/- 0.49 hours, the durations of clamping the portal vein and the infrahepatic vena cava of the recipient were 5.89 +/- 2.27 minutes and 3.89 +/- 0.73 minutes, respectively. In group B, the entire operative period was 4.12 +/- 0.51 hours with the duration of clamping portal vein and infrahepatic vena cava, 28.33 +/- 6.04 minutes and 12.16 +/- 3.72 minutes (P < .01 vs group A). In group A, mean arterial pressure dropped during the anhepatic phase but recovered quickly after reperfusion. The fluid infusion was about 730.56 +/- 50.56 mL in the group A and a pressor agent was unnecessary. In group B, blood pressure dropped during the anhepatic phase and slowly recovered. The fluid infusion was about 2241.67 +/- 390.78 mL and a pressor agent was used to maintain the blood pressure of the recipient. No twist or thrombus was discovered in the anastomoses group A and the endothelium at the site of anastomosis was entire. In group B, errhysis was common in the anastomotic stomas. Nine of 10 dogs in group A survived more than 3 days, the longest being 8 days, whereas four of the six dogs in group B survived less than 3 days.

CONCLUSION

The results showed that the anhepatic time was significantly shortened (about 5.89 +/- 2.27 minutes) in group A compared with group B and venovenous bypass was unnecessary. Magnetic rings could be used for rapid vascular reconstruction in canine liver transplantation model. The long-term results of this procedure should be clarified before it is applied in clinical practice in the future.

Conjugation metabolism of acetaminophen and bilirubin in extrahepatic tissues of rats

An anhepatic rat model was used to explore the extrahepatic conjugating metabolism of acetaminophen and serum bilirubin. The recovery of glucuronide- and sulfate-acetaminophen was 47.5% in normal control and 13.4% in model rats in the urine collected for 6 h after administration of acetaminophen 20 mg kg(-1). Following the increase of acetaminophen dose to 150 mg kg(-1), the recovery of urinary glucuronide-acetaminophen increased by 53.9% in normal control; but it decreased by 36.4% in model rats. In contrast to normal control, the pretreatment with phenobarbital did not affect acetaminophen and its metabolite levels in plasma and urine in model rats. After the establishment of anhepatic model the serum direct bilirubin rose dramatically. Urinary bilirubin test was positive in model rats, but not in normal control. No changes were observed in serum total bilirubin and ratio of direct/total bilirubin after the pretreatment with ranitidine or phenobarbital 50 mg kg (-1), i.p. for 5 days in model rats. The results indicate that the glucuronide- and sulfate-acetaminophen formed in the extrahepatic tissues of model rats is 28.2% of normal control, serum free bilirubin can be transformed into conjugated bilirubin in extrahepatic tissues, and the regulation mechanism of phase II conjugating enzymes is different between the hepatic and extrahepatic tissues.

[Postliposuction histologic alteration of adipose tissue in mini-pig models]

OBJECTIVE

To study the postliposuction histologic alterations of adipose tissue in Mini-pigs.

METHODS

Five Wuzhishan adult Mini-pigs were suctioned with syringe-assisted liposuction using a suction needle of 2 mm in diameter. The subcutaneous adipose tissues on both operated and controlled non-operated areas were collected from one week to eight months after operation and all samples were measured and observed macroscopically and microscopically.

RESULTS

The thickness of subcutaneous adipose tissues at the operated sites is thinner than the controlled sites. There was no significant difference in adipocyte morphology between the two kinds of samples. The structure of fat tissue recovered normally during 6-8 months after liposuction.

CONCLUSION

Liposuction is an effective operation to eliminate the subcutaneous adipose tissue and the structure of subcutaneous adipose tissue is completely normal in 6-8 months after the operation.