Biomedical subjects

W Liu

Publications and source records attributed to W Liu.

At least 109 records · Page 6Linked to original sources

PubMed2003

TGF beta 1 and biglycan, decorin, and fibromodulin metabolism in canine cartilage.

OBJECTIVE: Small proteoglycans (PGs) may accumulate in late stage osteoarthritis even as aggrecan is lost. It is not clear what role transforming growth factor (TGF) beta has in this accumulation. Our goal was to investigate the ability of TGF beta 1 to modulate the synthesis and accumulation of decorin, biglycan, and fibromodulin in cartilage explants cultured under conditions in which aggrecan synthesis remains relatively constant. DESIGN: Articular cartilage was cultured in the presence or absence of 4 ng/ml TGF beta 1 for up to 16 days. Material extracted from cartilage was assayed for 35SO(4)-large and small PGs and for total endogenous decorin, biglycan and fibromodulin. RESULTS: The synthesis of 35SO(4)-small PGs increased during the 16 days in culture in response to TGF beta 1, but declined in control cultures. The difference in 35SO(4)-decorin between TGF beta 1 and control samples reached nine-fold after 16 days, while the difference in total endogenous decorin was less than 1.5-fold. 35SO(4)-decorin, which was present in TGF beta 1-treated cultures had an identical core protein, but a longer glycosaminoglycan chain than that of decorin in control cultures. No significant differences in endogenous biglycan were detected, but accumulation of fibromodulin in TGF beta 1 explants exceeded fibromodulin in controls, on average, by 3.8-fold. Fibromodulin was present in cartilage in both keratan sulfate- and non-sulfated oligosaccharide-substituted forms. CONCLUSIONS: The accumulation of each of the three small PGs was affected to a different extent in response to TGF beta 1. Of the three, fibromodulin content was most rapidly augmented in response to TGF beta 1.

Animals↗

PubMed2003

Candidate gene approach: potentional association of caspase-1, inhibitor of apoptosis protein-1, and prosaposin gene polymorphisms with response to Salmonella enteritidis challenge or vaccination in young chicks.

Salmonella enteritidis (SE) contamination of poultry products is a major cause of foodborne disease worldwide. Caspase-1 and inhibitor of apoptosis protein-1 (IAP-1) were selected as candidate genes for chicken response to SE because their proteins play critical roles in the apoptotic pathway when intracellular bacteria interact with host cells. Prosaposin (PSAP) was selected as a positional candidate gene based on a previous quantitative trait loci (QTL) linkage study using the same population. The F1 offspring of outbred sires crossed with three diverse, highly inbred dam lines (two major histocompatibility complex-congenic Leghorn lines named G-B1 and G-B2, and one Fayoumi line) were used to define the phenotypes. The F1 birds were involved in either pathogenic SE challenge, in which spleen and cecum content bacterial load were quantified, or SE vaccination, in which plasma antibody level to SE vaccine was evaluated. A polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) assay was developed to identify single-nucleotide polymorphism (SNP) in the three genes. The F1 offspring of heterozygous sires for each gene were genotyped. The sire caspase-1 gene was significantly associated with cecum content bacterial load (P = 0.04) in the three combined dam line crosses, and with spleen bacterial load in the G-B1 cross (P=0.02). The sire caspase-1 gene was also significantly associated with antibody level to SE vaccine (P=0.03) in F1 males in the three combined dam line crosses. The sire IAP-1 gene was significantly associated with spleen bacterial load (P=0.04) in the three combined dam-line crosses, and interacted with dam-line genetics (P = 0.01) for cecum content bacterial load. The sire PSAP gene significantly interacted with sex for spleen bacterial load (P = 0.004). This study is the first to demonstrate the association of SNPs for caspase-1, IAP-1, and PSAP genes with SE vaccine and with pathogen challenge response in chickens.

Alleles↗

PubMed2003

Natural resistance-associated macrophage protein 1 gene polymorphisms and response to vaccine against or challenge with Salmonella enteritidis in young chicks.

Salmonella enteritidis (SE) contamination of poultry products is of global food-safety concern. The natural resistance-associated macrophage protein 1 (NRAMP1) affects host innate immunity to intracellular bacteria because of its ability to transport divalent cations in late endosome/lysosomes. Studying the association of the NRAMP1 gene and chicken innate immune response to SE can, therefore, aid understanding and enhancement of chicken genetic resistance to SE. The chicken NRAMP1 gene was investigated as a candidate gene for SE response in a unique resource population. Outbred broiler sires and three diverse, highly inbred dam lines (two major histocompatibility complex-congenic Leghorn and one Fayoumi line) produced F1 progeny that were evaluated as young chicks for either bacterial load in spleen and cecum after pathogenic SE inoculation or antibody level after SE vaccination. Thirty-seven single nucleotide polymorphisms (SNP) were identified in 3.1 kb of genomic DNA of the NRAMP1 gene. A PCR-RFLP assay was developed to identify a SNP in a conserved transport motif. The sire NRAMP1 gene SNP was associated (P < 0.02) with antibody level to SE vaccine for Sire 8170 offspring in the two Leghorn crosses. In Sire 8296 offspring, NRAMP1 was associated (P < 0.02) with spleen bacterial load in the combined dam-line crosses. This study demonstrated the association of a SNP polymorphism in a highly conserved region of NRAMP1 with SE vaccine and pathogen challenge response in young chicks, indicating that either NRAMP1 or a linked gene controls these SE-response traits.

Alleles↗

PubMed2003

Membrane bioreactors for treating waste streams.

Membrane bioreactors (MBRs) have a number of advantages for treating wastewater containing large quantities of BOD. This paper reviews the inherent advantages of an MBR, which include high potential biomass loadings, lower sludge yields, and retention of specialized organisms that may not settle well in clarifiers. A major problem in effluent treatment occurs when mixed inorganic and organic wastes occur with high concentrations of pollutants. Inorganics that might cause extremes of pH and/or salinity will inhibit microbial growth and only specialized organisms can survive under these conditions. Refractory organics are only biodegraded with difficulty by specialized organisms, which usually do not resist the extreme inorganic environments. The use of membrane bioreactors to help separate the micro-organisms from the inorganic compounds, yet permit the organics to permeate, has been developed in two different designs that are outlined in this paper. The use of membrane contactors in a multimembrane stripping system to treat acidic chlorinated wastes is proposed and discussed.

Biomass↗

PubMed2003

Complementary DNA macroarray analyses of differential gene expression in porcine fetal and postnatal muscle.

To study differential gene expression in porcine skeletal muscle, a porcine complementary DNA (cDNA) macroarray was produced that contained 327 expressed sequence tags (EST) derived from whole embryo and adult skeletal muscle, and differential display PCR products from fetal and postnatal muscle. Total RNA from four muscle samples, 75- and 105-d fetal hind limb muscles, and 1- and 7-wk postnatal semitendinosus muscle was used to make radiolabeled targets for duplicate hybridization to the macroarray membranes in an initial screen for expression. All EST that gave clear signals (n = 238) were then re-arrayed, and hybridization was conducted with additional biological replication of samples in the 75-d and 1-wk ages. Signal intensity for each gene was normalized to signal intensity measured at control spots on each membrane, which consisted of total cDNA from liver, lung, spleen, and skeletal muscle. Both normalized ratio levels and a mixed linear model analyses were used to identify genes differentially expressed among the muscle samples. Results showed 28 genes had differences in expression level greater than twofold between the 75-d fetal and 1-wk muscle RNA samples. All 28 genes were also identified as genes with significantly different (P < 0.01) expression using a mixed linear model analysis. Nineteen of these 28 genes had significant matches (basic local alignment search tool [BLAST] score > 100; P < 0.01) to known genes, two matched genes encoding human hypothetical proteins, and seven had no significant matches to Genbank nonredundant and dbEST (database of expressed sequence tags) entries. These results were confirmed for representative genes with RNA blot analysis of seven developmental time points, including RNA from the same muscle samples tested previously in the macroarray. The RNA blot results confirmed the macroarray results for all selected genes, demonstrating that the macroarray technique used in this study is accurate and reproducible. An unknown muscle clone (M218) with a slightly less than twofold increase in expression from the 75-d to the 1-wk age (1 wk/75 d = 1.94; P = 0.0114) was also shown to differ between these two ages using RNA blot analysis, demonstrating the methods used to identify differentially expressed genes may be conservative. The association between expression patterns of vimentin and desmin was also investigated. Results indicate the switch in intermediate filament protein from vimentin to desmin occurs primarily at the level of transcription and/or RNA processing.

Age Factors↗

PubMed2003

Controlled mechanical distension of the human oesophagus: sensory and biomechanical findings.

BACKGROUND: The relation between mechanical distension of the gut and the sensory response is poorly understood. The current experimental study aimed to examine the sensory response in the human oesophagus during on-line recording of the luminal pressure, cross-sectional area (CSA) and sensory rating using different distension rates before and during relaxation of the smooth muscle. METHODS: An impedance planimetric probe for bag distension of the oesophagus was used in 13 healthy subjects aged 43 +/- 15 years. Ramp distensions were done with an electromechanical pump using infusion rates of 10, 25 and 50 ml/min, with and without relaxation of the smooth muscle with butylscopolamine. The sensory intensity was measured using a 0-10 visual analogue scale (VAS), with 5 as the pain threshold. The pump was reversed at 8 on the scale, corresponding to medium pain intensity, and the pressure, volume, tension and CSA were evaluated. Finally, three isovolumetric experiments where the CSA was held constant for 2 min at initial VAS ratings of 3, 5 and 7 were performed. RESULTS: A total of 104 distension profiles were investigated. The volume at maximal pain intensity (VAS = 8) increased as a function of the distension rate (P < 0.001), whereas the pressure, tension and CSA were not affected. When the smooth muscle was relaxed, there was a 29% fall in pressure at maximal pain intensity (P = 0.004), a 27% fall in tension (P = 0.003), whereas CSA did not change (P = 0.3). When the pressure was recorded as a function of the sensory intensity, there was an exponential increase after the pain threshold was reached, whereas the stimulus-response functions for tension, volume and CSA were nearly linear. In the isovolumetric experiments the ratings during the three sensory intensities were the same in the individual subjects, but the between-individual pain response was variable, probably reflecting individual differences in adaptation/central integration. CONCLUSIONS: The study allowed us to assess the strain-rate dependency of both perception and biomechanical properties in the oesophagus. It was demonstrated that the pain response was related to the CSA (and hence strain), independently of the contractile state of the muscle and biomechanical behaviour of the tissue. The findings support the fact that the pain-sensitive mechanoreceptors in the human oesophagus depend on circumferential wall stretch rather than on pressure, tension and volume. The model should be used in future studies to investigate whether changes in strain are responsible for the oesophageal sensation in health and disease.

Adult↗

PubMed2002

White spot syndrome virus (WSSV) infects specific hemocytes of the shrimp Penaeus merguiensis.

White spot syndrome virus (WSSV) was specifically detected by PCR in Penaeus merguiensis hemocytes, hemolymph and plasma. This suggested a close association between the shrimp hemolymph and the virus. Three types of hemocyte from shrimp were isolated using flow cytometry. Dynamic changes of the hemocyte subpopulations in P. merguiensis at different times after infection were observed, indicating that the WSSV infection selectively affected specific subpopulations. Immunofluorescence assay (IFA) and a Wright-Giemsa double staining study of hemocyte types further confirmed the cellular localization of the virus in the infected hemocytes. Electron microscopy revealed virus particles in both vacuoles and the nucleus of the semigranular cells (SGC), as well as in the vacuoles of the granular cells (GC). However, no virus could be detected in the hyaline cells (HC). Our results suggest that the virus infects 2 types of shrimp hemocytes--GCs and SGCs. The SGC type contains higher virus loads and exhibits faster infection rates, and is apparently more susceptible to WSSV infection.

Animals↗

PubMed2002

Angiopoietin-1 inhibits tumour growth and ascites formation in a murine model of peritoneal carcinomatosis.

Angiopoietin-1 is an important regulator of endothelial cell survival. Angiopoietin-1 also reduces vascular permeability mediated by vascular endothelial growth factor. The effects of angiopoietin-1 on tumour growth and angiogenesis are controversial. We hypothesised that angiopoietin-1 would decrease tumour growth and ascites formation in peritoneal carcinomatosis. Human colon cancer cells (KM12L4) were transfected with vector (pcDNA) alone (control) or vector containing angiopoietin-1 and injected into the peritoneal cavities of mice. After 30 days, the following parameters were measured: number of peritoneal nodules, ascites volume, and diameter of the largest tumour. Effects of angiopoietin-1 on vascular permeability were investigated using an intradermal Miles assay with conditioned media from transfected cells. Seven of the nine mice in the pcDNA group developed ascites (1.3+/-0.5 ml (mean+/-s.e.m.)), whereas no ascites was detectable in the angiopoietin-1 group (0 out of 10) (P<0.01). Number of peritoneal metastases (P<0.05), tumour volume, (P<0.05), vessel counts (P<0.01), and tumour cell proliferation (P<0.01) were significantly reduced in angiopoietin-1-expressing tumours. Conditioned medium from angiopoietin-1-transfected cells decreased vascular permeability more than did conditioned medium from control cells (P<0.05). Our results suggest that angiopoietin-1 is an important mediator of angiogenesis and vascular permeability and thus could theoretically serve as an anti-neoplastic agent for patients with carcinomatosis from colorectal cancer.

Angiogenesis Inducing Agents↗

PubMed2002

Candidate genes for resistance to Salmonella enteritidis colonization in chickens as detected in a novel genetic cross.

Salmonellosis is a zoonotic disease that is problematic for both animal production and food safety. A novel genetic cross, named the Iowa Salmonella response resource population (ISRRP), was established to elucidate the genetic control of resistance to Salmonella enteritidis (SE) colonization in young chicks, to characterize unique resistance alleles, and to estimate gene interaction effects. Outbred broiler sires were mated with dams of diverse, highly inbred, light-bodied lines to produce an F(1) generation that was informative for all heterozygous alleles of the sires. Mating F(1) sires back to dams of the corresponding inbred line produced a backcross generation. To mimic the natural route of exposure and thus afford the opportunity to investigate mucosal immunity, pathogenic SE were inoculated into the esophagus of day-old chicks. After 1 week, the SE colonizing the cecal lumen and the spleen were enumerated. Candidate genes were selected for analysis based upon one of the two criteria. Functional candidates were genes with reported activity related to the tested traits. Positional candidates were genes mapped near microsatellites that were linked, in other phases of this project, with antibody levels to SE vaccine. Broiler sire alleles of the MHC class I, NRAMP1, PSAP, and IAP1 genes showed association with SE colonization in the F(1) generation of this novel disease resistance resource population.

Alleles↗

PubMed2002

Sonic hedgehog regulates otic capsule chondrogenesis and inner ear development in the mouse embryo.

Development of the cartilaginous capsule of the inner ear is dependent on interactions between otic epithelium and its surrounding periotic mesenchyme. During these tissue interactions, factors endogenous to the otic epithelium influence the differentiation of the underlying periotic mesenchyme to form a chondrified otic capsule. We report the localization of Sonic hedgehog (Shh) protein and expression of the Shh gene in the tissues of the developing mouse inner ear. We demonstrate in cultures of periotic mesenchyme that Shh alone cannot initiate otic capsule chondrogenesis. However, when Shh is added to cultured periotic mesenchyme either in combination with otic epithelium or otic epithelial-derived fibroblast growth factor (FGF2), a significant enhancement of chondrogenesis occurs. Addition of Shh antisense oligonucleotide (AS) to cultured periotic mesenchyme with added otic epithelium decreases levels of endogenous Shh and suppresses the chondrogenic response of the mesenchyme cells, while supplementation of Shh AS-treated cultures with Shh rescues cultures from chondrogenic inhibition. We demonstrate that inactivation of Shh by targeted mutation produces anomalies in the developing inner ear and its surrounding capsule. Our results support a role for Shh as a regulator of otic capsule formation and inner ear development during mammalian embryogenesis.

Animals↗

PubMed2002

Detection of white spot syndrome virus (WSSV) of shrimp by means of monoclonal antibodies (MAbs) specific to an envelope protein (28 kDa).

The vp28 gene encoding an envelope protein (28 kDa) of white spot syndrome virus (WSSV) was amplified from WSSV-infected tiger shrimp that originated from Malaysia. Recombinant VP28 protein (r-28) was expressed in Escherichia coli and used as an antigen for preparation of monoclonal antibodies (MAbs). Three murine MAbs (6F6, 6H4 and 9C10) that were screened by r-28 antigen-based enzyme-linked immunosorbent assay (ELISA) were also able to recognize viral VP28 protein as well as r-28 on Western blot. Three non-overlapping epitopes of VP28 protein were determined using the MAbs in competitive ELISA; thus, an antigen-capture ELISA (Ac-ELISA) was developed by virtue of these MAbs. Ac-ELISA can differentiate WSSV-infected shrimp from uninfected shrimp and was further confirmed by a polymerase chain reaction (PCR) and Western blot. Approximately 400 pg of purified WSSV sample and 20 pg of r-28 could be detected by Ac-ELISA, which is comparable in sensitivity to PCR assay but more sensitive than Western blot in the detection of purified virus. Hemolymph and tissue homogenate samples collected from a shrimp farm in Malaysia during December 2000 and July 2001 were also detected by Ac-ELISA and PCR with corroborating results.

Animals↗

PubMed2002

Trek-like potassium channels in rat cardiac ventricular myocytes are activated by intracellular ATP.

Large (111 +/- 3.0 pS) K+ channels were recorded in membrane patches from adult rat ventricular myocytes using patch-clamp techniques. The channels were not blocked by 4-AP (5 mM), intracellular TEA (5 mM) or glybenclamide (100 mM). Applying stretch to the membrane (as pipette suction) increased channel open probability (Po) in both cell-attached and isolated patches (typically, Po approximately equals 0.005 with no pressure; approximately equals 0.328 with 90 cm H2O: Vm = 40 mV, pHi = 7.2). The channels were activated by a decrease in intracellular pH; decreasing pHi to 5.5 from 7.2 increased Po to 0.16 from approx. 0.005 (no suction, Vm held at 40 mV). These properties are consistent with those demonstrated for TREK-1, a member of the recently cloned tandem pore family. We confirmed, using RT-PCR, that TREK-1 is expressed in rat ventricle, suggesting that the channel being recorded is indeed TREK-1. However, we show also that the channels are activated by millimolar concentrations of intracellular ATP. At a pH of 6 with no ATP at the intracellular membrane face, Po was 0.048 +/-0.023, whereas Po increased to 0.22 +/- 0.1 with 1 mM ATP, and to 0.348 +/- 0.13 with 3 mM (n = 5; no membrane stretch applied). The rapid time course of the response and the fact that we see the effect in isolated patches appear to preclude phosphorylation. We conclude that intracellular ATP directly activates TREK-like channels, a property not previously described.

Adenosine Triphosphate↗

PubMed2002

The role of the haematopoietic tissue in haemocyte production and maturation in the black tiger shrimp (Penaeus monodon).

The haematopoietic tissue (HPT) of the black tiger shrimp (Penaeus monodon) is located in different areas in the cephalothorax, mainly at the dorsal side of the stomach and in the onset of the maxillipeds and, to a lesser extent, towards the antennal gland. In young and in experimentally stimulated animals, the HPT is expanded in relatively larger and more numerous lobules throughout the cephalothorax. Four cell types could be identified in the HPT by electron microscopy. The type 1 cells are the presumed precursor cells that give rise to a large- and a small-granular young haemocyte, denominated as the type 2 and type 3 cells, respectively. A gradient of maturation from the type 1 towards the type 2 or 3 cells could frequently be observed. The presumed precursor cells are located towards the exterior of the lobules and maturing young haemocytes towards the inner part, where they can be released into the haemal lacunae. The type 4 cells show typical features of interstitial cells. Different stimulation experiments were carried out and various techniques were used to study the HPT in relation to the (circulating) haemocytes. The majority of the cells in the HPT are able to proliferate and proliferation can be increased significantly after the injection of saline and, to a much higher extent, after LPS injection. The circulating haemocytes of crustaceans are generally divided into hyaline (H), semigranular (SG) or granular (G) cells, of which large- and small-granular variants of each of these were suggested in the present study. Even after stimulation in this study, the circulating haemocytes scarcely divide. The high variations that were found in the total haemocyte count in the stimulation experiments were not accompanied by significant differences in differential haemocyte count and, therefore, appeared to be a less useful indicator of stress or health in P. monodon. Light and electron microscopical observations support the regulation of the populations of the different haemocyte types in the circulation by (stored) haemocytes from the connective tissue. In conclusion, according to morphological and immuno-chemical criteria, it is proposed in the present study to divide the haemocytes into a large-and a small-granular developmental series. After extensive morphological observations, it is suggested that the hyaline cells are the young and immature haemocytes of both the large- and small-granular cell line that are produced in the HPT, and can be released into the haemolymph. Indications were found that the granular cells, of at least the large-granular cell line, mature and accumulate in the connective tissue and are easily released into the haemolymph. Combining the results of the present study with literature, this proposed model for haemocyte proliferation, maturation and reaction will be discussed.

Animals↗

PubMed2002

Investigation of assimilable organic carbon (AOC) and bacterial regrowth in drinking water distribution system.

This paper investigated the variation of assimilable organic carbon (AOC) concentrations in water from several typical water treatment plants and distribution systems in a northern city of China. It is concluded from this study that: (1) The AOC in most of the product water of the studied water treatment plants and the water from the associated distribution systems could not meet the biostability criteria of 50-100 microg/L. (2) Only 4% of the measured AOC concentrations were less than 100 microg/L. However, about half of the measured AOC values were less than 200 microg/L. (3) Better source water quality resulted in lower AOC concentrations. (4) The variation of AOC concentrations in distribution systems was affected by chlorine oxidation and bacterial activity: the former resulted in an increase of AOC value while the latter led to a reduction in AOC. (5) The variation of AOC concentration followed different patterns in different distribution systems or different seasons due to their respective operational characteristics. (6) Less than 30% of AOC could be removed by a conventional treatment process, whereas 30-60% with a maximum of 50-60% could be removed by granular activated carbon (GAC). (7) The observation via scanning electron microscope (SEM) on distribution pipe tubercle samples demonstrated that the pipe inner wall was not smooth and bacteria multiplied in the crevice as well as in the interior wall of distribution pipes.

Bacteria↗

PubMed2002

Effects of combination anti-vascular endothelial growth factor receptor and anti-epidermal growth factor receptor therapies on the growth of gastric cancer in a nude mouse model.

We hypothesised that the combination of anti-angiogenic and anti-epidermal growth factor (EFG)-receptor (R) therapies would more effectively inhibit gastric cancer growth than single-agent therapy. TMK-1 gastric cancer cells were injected into the gastric wall of nude mice to generate tumours. After 4 days, mice were randomly assigned to the following groups: control, DC101 ([vascular endothelial growth factor (VEGF)-receptor (R)-2 antibody], C225 (EGF-R antibody), or a combination of DC101 and C225. The combination therapy significantly inhibited gastric tumour growth compared with the control group, whereas the decrease in tumour growth in mice treated with DC101 or C225 alone did not reach statistical significance. All mice administered DC101 demonstrated decreased tumour vascularity and increased endothelial cell apoptosis. C225 alone did not affect angiogenesis, but inhibited tumour cell proliferation. The combination therapy led to a further decrease in tumour cell proliferation. The combination of anti-VEGF-R and anti-EGF-R therapies was effective in inhibiting gastric cancer growth. These findings support the hypothesis that inhibiting multiple biological pathways that mediate tumour growth may be an effective therapeutic strategy.

Animals↗

PubMed2002

Acyl-CoA Z9- and Z10-desaturase genes from a New Zealand leafroller moth species, Planotortrix octo.

Two cDNAs encoding acyl-CoA Z9-desaturase from the fat body and Z10-desaturase from the pheromone gland of the greenhead leafroller moth, Planotortrix octo, were obtained by RACE PCR. The Z9-desaturase (Pocto-Z9) cDNA spans 2291 nt with an ORF encoding a 352 amino-acid protein, which has 65% identity to Trichoplusia ni Delta 9 desaturase (Tni-Z9). The Z10-desaturase (Pocto-Z10) cDNA spans 2777 nt with an ORF encoding a protein with 356 amino acids. Pocto-Z10 shows lower identity to Pocto-Z9 and Tni-Z9 (48 and 46%, respectively) and relatively higher identity to the Delta 11 desaturases of T. ni and Helicoverpa zea (57 and 56%, respectively). The ORFs of these two P. octo cDNAs were constructed into an expression vector, YEpOLEX, that complemented the unsaturated fatty acid (UFA) auxotrophy of a desaturase-deficient ole1 strain of Saccharomyces cerevisiae. Expression of Pocto-Z9 produced a 5:2 ratio of Z9-16 and Z9-18 acids, with minor amounts (<4%) of Z9-14, Z9-15, and Z9-17 acids. Pocto-Z10 was successfully expressed in the YEpOLEX system when complemented with Z11-18:Me, and the major desaturase product proved to be Z10-16:Acid. The results confirm the regio- and stereo-selectivity of this unusual Delta 10 desaturase.

Amino Acid Sequence↗

PubMed2002

Identification of individual walking patterns using time discrete and time continuous data sets.

Scientific studies typically treat data by studying effects of groups. Clinical therapy typically treats patients on a subject specific basis. Consequently, scientific and clinical attempts to help patients are often not coordinated. The purposes of this study were (a) to identify subject and group specific locomotion characteristics quantitatively, using time discrete and time continuous data and (b) to assess the advantages and disadvantages of the two approaches. Kinematic and kinetic gait pattern of 13 female subjects walking in dress shoes with different heel heights (14, 37, 54 and 85 mm) were analysed. The results of this study showed that subject specific gait characteristics could be better identified with the time continuous than with the time discrete approach. Thus, the time continuous approach using artificial networks is an effective tool for identifying subject and group specific locomotion characteristics.

Adult↗

PubMed2002

Roles of disulfide bridges in scorpion toxin BmK M1 analyzed by mutagenesis.

The unique fold of scorpion toxins is a natural scaffold for protein engineering, in which multiple disulfide bonds are crucial structural elements. To understand the respective roles of these disulfide bridges, a mutagenesis analysis for the four disulfide bonds, 12-63, 16-36, 22-46 and 26-48, of a representative toxin BmK M1 from the scorpion Buthus martensii Karsch was carried out. All cysteines were replaced by serine with double mutations. The recombinant mutants were expressed in the Saccharomyces cerevisiae S-78 system. Toxic activities of the expressed mutants were tested on ICR mice in vivo and on neuronal Na+ channels (rNav1.2) by electrophysiological analysis. Recombinant variants M1 (C22S,C46S) and M1 (C26S,C48S) were not expressed at all; M1 (C16S,C36S) could be expressed at trace levels but was extremely unstable. Variant M1 (C12S,C63S) could be expressed in an amount comparable with that of unmodified rBmK M1, but had no detectable bioactivities. The results indicated that among the four disulfide bonds for long-chain scorpion toxins, loss of either bridge C22-C46 or C26-C48 is fatal for the general folding of the molecule. Bridge C16-C36 mainly contributes to the global stability of the folded scaffold, and bridge C12-C63 plays an essential role in the functional performance of scorpion toxins.

Amino Acid Sequence↗