Search PubMed⌕ Search

Biomedical subjects

Y Pang

Publications and source records attributed to Y Pang.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Studies on microbial production of undecane 1, 11-dicarboxylic acid from N-tridecane].

A mutant, Candida tropicalis P-12-242, which can produce undecane 1, 11-Dicarboxylic acid(DC13) from N-Tridecane(nC13), was obtained by treating the parent stain UH-2-48 with sodium nitrite. On 2500L fermenter testing, under the optimum condition where the fermentation medium contained total 26% nC13, pH of the course of fermentation was maintained range 7.5-8.0, at 28 degrees C-30 degrees C, the highest level of DC13 production was obtained after 6 d, and the average amount of DC13 accumulated was 182.6 g/L in broth. After received residual nC13, The average consumption rate of DC13 from nC13 was 87.8%. The purity of the product DC13, which was analyzed by gas chromatography was about 96.8%.

Alkanes↗
PubMed1999

[First discovery of Taenia saginata asiatica infection in Yunnan province].

AIM: To investigate the aetiology, species and epidemiological factors of Taenia infection in a pilot area of Lanping County, Yunnan Province. METHODS: Two patients with taeniasis were treated with antiscolex capsule and praziquantel, respectively. Five local weaning pigs free from tapeworm infection were fed with gravid proglottids obtained from the patients. After 2-3 months, the pigs were necropsied to examine cysticerci. In addition, one pig naturally infected with Taenia was treated as well. RESULTS: Based on morphological characteristics of the scolex and gravid proglottid of four tapeworms obtained from the patients, the worms were similar to T. saginata. 23 cysticerci recovered from two experimentally infected pigs were found in the livers, omentum majus and mesenterium, and 3 cysticerci were found in the liver and omentum majus in a naturally infected pig as well. The protoscolex of mature Cysticercus had two rows of rudimentary hooklets, one rostellum and four acetabula resembling to C. cellulosae. According to morphological characteristics and the location of cysticerci, the tapeworm was identified as Taenia saginata asiatia. CONCLUSION: T. saginata asiatica infection was first reported in Yunnan Province.

Adult↗
PubMed1998

NMR solution structure of the 21 kDa chaperone protein DnaK substrate binding domain: a preview of chaperone-protein interaction.

The solution structure of the 21 kDa substrate-binding domain of the Escherichia coli Hsp70-chaperone protein DnaK (DnaK 386-561) has been determined to a precision of 1.00 A (backbone of the beta-domain) from 1075 experimental restraints obtained from multinuclear, multidimensional NMR experiments. The domain is observed to bind to its own C-terminus and offers a preview of the interaction of this chaperone with other proteins. The bound protein region is tightly held at a single amino acid position (a leucyl residue) that is buried in a deep pocket lined with conserved hydrophobic residues. A second hydrophobic binding site was identified using paramagnetically labeled peptides. It is located in a region close to the N-terminus of the domain and may constitute the allosteric region that links substrate-binding affinity with nucleotide binding in the Hsp70 chaperones.

Amino Acid Sequence↗
PubMed1998

Tetracycline resistance in Staphylococcus spp. from domestic animals.

A total of 838 staphylococcal isolates representing 19 different species were obtained from cattle, cats, dogs, ducks, guinea pigs, horses, mink, pigeons, pigs, rabbits, and turkeys. From these 228 (27.2%) isolates were shown to be resistant to tetracycline and to carry one or two of the tetracycline resistance (tet) genes tet (K), tet (L), tet (M), or tet (O) with seven different distribution patterns. Additional resistances to one or more antibiotics were observed in 153 (67.1%) of the tetracycline resistant isolates. The tet (M) gene was found in 94.3% of the resistant S. intermedius isolates while the tet (K) gene predominated in most of the other staphylococcal species irrespective of the host animal. The tet (K) and tet (L) genes were located on plasmids while the tet (M) and tet (O) genes appeared to be associated with the chromosome.

Animals↗
PubMed1998

High-resolution detection of five frequencies in a single 3D spectrum: HNHCACO--a bidirectional coherence transfer experiment.

A new triple-resonance pulse sequence, 3D HNHCACO, is introduced and discussed, which identifies sequential correlations of the backbone nuclei (H alpha (i-1), C alpha (i-1), C(i-1), NH(i), N(i)) of doubly labeled proteins in H2O. The three-dimensional (3D) method utilizes a recording of 15N and 13C resonances in a single indirect time domain, the 13C' resonance in another indirect time domain, and detects both NH and H alpha protons. A bidirectional coherence transfer (NH(i) <--> N(i) <--> C(i-1) <--> C alpha (i-1) <--> H alpha (i-1)) is effectuated, resulting in a single high-resolution 3D spectrum that contains the frequencies of all five backbone nuclei. The experiment was applied to the 12.3 kDa ribonuclease from Bacillus intermedius (Binase).

Bacillus↗
PubMed1998

Expression of c-Fos protein in the spinal cord after brachial plexus injury: comparison of root avulsion and distal nerve transection.

OBJECTIVE: Clinical reports indicate poor outcomes for avulsion injuries, compared with more peripheral nerve damage. These two different injuries may both affect gene expression in spinal neurons, and the changes in gene expression may be related to the types of injuries. METHODS: The brachial plexus of 48 adult male rats was lesioned by either root avulsion close to the spinal cord or distal nerve transection. The rats were quickly revived and remained awake until death at 30, 60, or 120 min after surgery. In rats with avulsive injuries, traumatic sites on the dorsal and ventral horns of the spinal cord were microscopically detected. Immunocytochemical analysis of the c-fos product was performed for the two experimental groups and for sham-treated control animals at the same survival times. RESULTS: An increase in Fos-like immunoreactivity (FLI) in cells of the spinal cord, at levels C4-T1, was detected at 30 min after nerve transection or root avulsion. The number of FLI-positive cells continued to increase at 60 and 120 min after the nerve injury (P=0.001). FLI-positive cells were compared at the C7 level, in laminae 1 and 2, 3 and 4, and 5 to 10, after the two injuries and were found to be more abundant after the avulsive injury (P=0.0001); furthermore, the number of FLI-positive cells increased with time (P=0.001). In a comparison of all levels, both experimental groups demonstrated significantly greater numbers of FLI-positive cells than did controls, and the group with nerve root avulsion showed significantly (P=0.0001) more FLI-positive cells than did the group with distal nerve transection. CONCLUSION: These results suggest that nerve root avulsion from the spinal cord leads to increased and prolonged expression of c-fos and, potentially, greatly increased transcription of new messages for recovery, survival, or cell death.

Animals↗
PubMed1997

Mycobacterium tuberculosis efpA encodes an efflux protein of the QacA transporter family.

The Mycobacterium tuberculosis H37Rv efpA gene encodes a putative efflux protein, EfpA, of 55,670 Da. The deduced EfpA protein was similar in secondary structure to Pur8, MmrA, TcmA, LfrA, EmrB, and other members of the QacA transporter family (QacA TF) which mediate antibiotic and chemical resistance in bacteria and yeast. The predicted EfpA sequence possessed all transporter motifs characteristic of the QacA TF, including those associated with proton-antiport function and the motif considered to be specific to exporters. The 1,590-bp efpA open reading frame was G+C rich (65%), whereas the 40-bp region immediately upstream had an A+T bias (35% G+C). Reverse transcriptase-PCR assays indicated that efpA was expressed in vitro and in situ. Putative promoter sequences were partially overlapped by the A+T-rich region and by a region capable of forming alternative secondary structures indicative of transcriptional regulation in analogous systems. PCR single-stranded conformational polymorphism analysis demonstrated that these upstream flanking sequences and the 231-bp, 5' coding region are highly conserved among both drug-sensitive and multiply-drug-resistant isolates of M. tuberculosis. The efpA gene was present in the slow-growing human pathogens M. tuberculosis, Mycobacterium leprae, and Mycobacterium bovis and in the opportunistic human pathogens Mycobacterium avium and Mycobacterium intracellular. However, efpA was not present in 17 other opportunistically pathogenic or nonpathogenic mycobacterial species.

Amino Acid Sequence↗
PubMed1997

[Protein kinase C involved in the protecttve effect of anoxic preconditioning on vascular smooth muscle cells].

It has been known that anoxic preconditioning (APC) has protective effects not only on cardiomyocyte, but also on vasculature. However, the effects of APC on vascular smooth muscle cells (VSMC) is unknown. On the model of anoxia/reoxygenation (A/R) injury of rabbit VSMC, the effect of APC was observed. It was found that APC could increase the survival rate of VSMC after A/R injury, lower the leakage of lactate dehydrogenase (LDH) and protein from cells, and attenuate peroxidation injury and calcium overload of VSMC. The results also showed that PMA, an activator of protein kinase C (PKC), could mimic, but H7 or polymyxin B (inhibitors of PKC) could abolish the above protective effect of APC. It is suggested that the protective effect of APC on VSMC during A/R injury might be due to the activation of PKC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1997

[The effect of endurance training and exhaustive exercise on metallothionein in rats].

To understand physiological role of metallothionein (MT) during exercise, MT levels in liver, brain, heart, lung, blood vessel, skeletal muscle and serum were observed in rats. The results showed that the levels of MT were decreased by 13-34% in lung, liver, heart and skeletal muscle of rats trained by swimming for 10 weeks and were increased by 21%-75% in skeletal muscle, heart, brain, lung and liver of rats after exhaustive swimming respectively, compared with normal control rats. (P < 0.05 and P < 0.01). But the levels of MT in blood vessel and serum were not changed in two groups of rats by swimming for 10 weeks and acute exhaustive swimming (P > 0.05). It is suggested that the different changes of MT levels under physical training and acute exhaustive exercise may be of importance in protection against oxygen free radicals.

Animals↗
PubMed1997

[Changes of 5-HT2A receptor binding on platelet of patients with CAD and the effects of exercise test].

It is known both 5-HT2A receptors of platelet and vascular smooth muscle regulate vascular constriction and platelet aggregation to 5-HT challenge. And that 5-HT-induced hypperreactivity of vascular smooth muscle and platelet were noted in patients with coronary artery disease (CAD). In order to investigate the mechanism of platelet hyperreactivity in cardiovascular disease. Platelet 5-HT2A receptor were measured by specific binding of 3H-ketanserin in patients with CAD (CAD group) and patients with chest pain but without CAD as well as healthy subjects (control group) before and after submaximal treadmill exercise. At the same time the levels of plasma 5-HT were also measured. The results showed: (1) In the resting state, 3H-ketanserin exhibited saturable binding with Bmax of 71.1 +/- 10.1 fmol/mg protein, Kd 1.35 +/- 0.20 nmol/L in control group (n = 8) and with Bmax of 102.1 +/- 22.2 fmol/mg protein, Kd 2.44 +/- 0.66 nmol/L in CAD group (n = 10). Between two groups had no significant difference (P > 0.05). And the specific binding of 2.0 nmol/L 3H-ketanserin and the level of plasma 5-HT in CAD group were higher than those in control group (P < 0.05). (2) After exercise all of the specific binding of 2.0 nmol/L 3H-ketanserin, Bmax of receptor binding and the level of plasma 5-HT were significantly increased in CAD group but not in control group. The above results suggested that the up-regulation of platelet 5-HT2A receptor was involved in the platelet hyperreactivity in CAD. The submaximal treadmill exercise had no significant effect on platelet function in control group, but it could lead to platelet 5-HT2A receptor increment and platelet activation in CAD group. Therefore, these changes of platelet might play a role in the acute myocardial ischemia induced by exercise.

Adult↗
PubMed1997

[Serological survey of human T lymphotropic virus type I (HTLV-1) IgG antibody in south region of Xinjiang].

Human T lymphotropic virus type-1 (HTLV-1) is endemic in southwestern Japan, Seychelles Islands, Caribbean basin, Brazil, and Sub Saharan Africa. Recently, the prevalence of HTLV-1 of domestic source has been reported from Beijing, Fujian and so forth. The object of our study is to know whether the prevalence of HTLV-1 is present in Xinjiang. We collected 2642 serm samples of various ages and different nationalities (Uigur, Han and Khalkhas) from south region of Xinjiang and tested for determination of HTLV-1 IgG antibody by IFA. The results showed that the total positive rate of HTLV-1 IgG was 0.34% (9/2642), of which Uigur nationality was 0.74% (8/1082), Khalkhas nationality was 0.21 (1/471), Han nationality was zero (0/1089). This data indicated that there are HTLV-1 infection among the population of Xinjiang and especially in Uigur and Khalkhas. Why did the minority nationalities have relatively high frequency of HTLV-1 infection? This needs to be studied further.

Adolescent↗
PubMed1997

Production of recombinant goldfish growth hormone I in a baculovirus expression system.

The cDNA sequence encoding the growth hormone (GH) I gene of goldfish (gf GH-I) was cloned into the pSXIVVI+ X3 baculovirus transfer vector. This transfer vector, without the initiation codon (ATG) and using a SynXIV promoter to activate transcription, was constructed for a baculovirus expression system. The recombinant transfer vector with the gf GH-I insert was used to produce the recombinant baculovirus TnNPV-SX+ gf GH-I 21a. Both in vivo and in vitro approaches were used to test the expression of growth hormone I gene using TnNPV-SX+ gf GH-I 21a. For in vivo studies, larvae of Trichoplusia ni were infected with the recombinant baculovirus. Four days later, growth hormone-like immunoreactivity was detected in the hemolymph of these infected larvae. For in vitro studies, insect Spodoptera frugiperda 9(Sf9) cells were infected with TnNPV-SX+ gf GH-I 21a. After incubation for at least 24 hours, growth hormone-like immunoreactivity was detected in Sf9 insect cells as well as in the culture medium. Western blotting analysis of larval hemolymph and Sf9 cell contents after viral infection revealed a protein band of 22.5 kDa immunoreactive to goldfish growth hormone antiserum. This is consistent with the predicted molecular weight deduced from the cDNA of goldfish growth hormone I gene. These results, taken together, suggest that the baculovirus expression system can be used to produce the recombinant growth hormone of a fish species.

Animals↗
PubMed1996

Inducible nitric oxide synthase and the regulation of central vessel caliber in the fetal rat.

BACKGROUND: The purpose of this study was to evaluate the possibility that inducible nitric oxide synthase (iNOS) regulates the fetal circulation. METHODS AND RESULTS: Positive evidence for iNOS gene expression was noted in heart central vessels and placenta of untreated rat fetuses. Rats in the last week of pregnancy were treated for 5 days with L-NG-(1-Iminoethyl)lysine (L-NIL), a selective inhibitor of iNOS, at 1, 10, and 100 micrograms/mL in the drinking water. To raise NO levels, lipopolysaccharide (LPS) 30 micrograms/kg was given by intraperitoneal injection, and sodium nitroprusside (SNP) was placed in mini-osmotic pumps to deliver 10 micrograms/kg per minute. Control animals were undisturbed. On day 21 of gestation, dams were anesthetized and fetuses were delivered by cesarean section and rapidly frozen in isopentane chilled in liquid nitrogen. Frozen sections (10 microns) were used to reconstruct a computer-generated three-dimensional image of the great vessels and ductus arteriosus. Significant constriction of the great vessels and ductus arteriosus was observed with L-NIL, whereas both LPS and SNP dilated these vessels. The vasorelaxant effect of LPS was blocked by L-NIL. NO release from placental explants was 633 +/- 41 nmol/L under basal conditions, increasing to 4.0 +/- 0.4 mumol/L with LPS administration, although placental iNOS message and protein levels were unchanged. CONCLUSIONS: We suggest that nitric oxide, generated by iNOS, plays a significant role in control of major vessel and ductus arteriosus caliber in the rat fetus. In regard to the nitrergic regulation of the circulation, the fetus is clearly different from the adult.

Animals↗
PubMed1996

Construction of an insecticidal baculovirus expressing insect-specific neurotoxin AaIT.

Considering the factors which affect gene transcription, translation and the stability of mRNA, without changing the amino acid composition of the encoded polypeptide, AaIT gene encoding insect-specific neurotoxin was designed and synthesized according to bias in codon choice, overall G+C content and G+C content of bases at the third position in codons of polyhedrin genes of baculovirus and of plant genes as well. AaIT gene was fused behind a synthetic gp67 signal sequence and then recombined into the genome of Trichoplusia ni nuclear polyhedrosis virus (TnNPV) by transfer vector pSXIV VI+X3. The recombinant virus TnNPV-AaIT (occ+-gal-) was screened. The results of Southern blotting and SDS-PAGE demonstrated that AaIT gene had integrated into the genome of virus and expressed. Bioassays on the 3rd-instar Trichoplusia ni larvae showed that recombinant viruses TnNPV-AaIT could shorten the time of killing insect and improve the efficacy of killing agronomically important insects.

Animals↗