Identification of ammonia and volatile phenols as primary toxicants in a coal gasification effluent.
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Ammonia↗
Biomedical subjects
H Jin
Publications and source records attributed to H Jin.
Multifunctionality and diversity within the plant MYB-gene family.
MYB proteins constitute a diverse class of DNA-binding proteins of particular importance in transcriptional regulation in plants. Members are characterised by having a structurally conserved DNA-binding domain, the MYB domain. Different categories of MYB proteins can be identified depending on the number of imperfect repeats of the MYB domain they contain. It is likely that single MYB-domain proteins, a class of expanding importance in plants, bind DNA in a different way than two-repeat or three-repeat MYB proteins, and these groups are therefore likely to have different functions. The two-repeat (R2R3) MYB family is the largest family characterised in plants, and there are estimated to be over 100 members in Arabidopsis. Functions of MYB proteins in plants include regulation of secondary metabolism, control of cellular morphogenesis and regulation of meristem formation and the cell cycle. Although functional similarities exist between R2R3 MYB proteins that are closely related structurally, there are significant differences in the ways very similar proteins function in different species and also within the same organism. Therefore, despite the large number of R2R3 MYB proteins in plants, it is unlikely that many are precisely redundant in their functions, but more likely that they share overlapping functions.
Arabidopsis Proteins↗
Gene expression analysis by transcript profiling coupled to a gene database query.
We describe an mRNA profiling technique for determining differential gene expression that utilizes, but does not require, prior knowledge of gene sequences. This method permits high-throughput reproducible detection of most expressed sequences with a sensitivity of greater than 1 part in 100,000. Gene identification by database query of a restriction endonuclease fingerprint, confirmed by competitive PCR using gene-specific oligonucleotides, facilitates gene discovery by minimizing isolation procedures. This process, called GeneCalling, was validated by analysis of the gene expression profiles of normal and hypertrophic rat hearts following in vivo pressure overload.
Animals↗
Function search in a large transcription factor gene family in Arabidopsis: assessing the potential of reverse genetics to identify insertional mutations in R2R3 MYB genes.
More than 92 genes encoding MYB transcription factors of the R2R3 class have been described in Arabidopsis. The functions of a few members of this large gene family have been described, indicating important roles for R2R3 MYB transcription factors in the regulation of secondary metabolism, cell shape, and disease resistance, and in responses to growth regulators and stresses. For the majority of the genes in this family, however, little functional information is available. As the first step to characterizing these genes functionally, the sequences of >90 family members, and the map positions and expression profiles of >60 members, have been determined previously. An important second step in the functional analysis of the MYB family, through a process of reverse genetics that entails the isolation of insertion mutants, is described here. For this purpose, a variety of gene disruption resources has been used, including T-DNA-insertion populations and three distinct populations that harbor transposon insertions. We report the isolation of 47 insertions into 36 distinct MYB genes by screening a total of 73 genes. These defined insertion lines will provide the foundation for subsequent detailed functional analyses for the assignment of specific functions to individual members of the R2R3 MYB gene family.
Arabidopsis↗
Effect of multiple mutations in the hemoglobin- and hemoglobin-haptoglobin-binding proteins, HgpA, HgpB, and HgpC, of Haemophilus influenzae type b.
Haemophilus influenzae requires heme for growth and can utilize hemoglobin and hemoglobin-haptoglobin as heme sources. We previously identified two hemoglobin- and hemoglobin-haptoglobin-binding proteins, HgpA and HgpB, in H. influenzae HI689. Insertional mutation of hgpA and hgpB, either singly or together, did not abrogate the ability to utilize or bind either hemoglobin or the hemoglobin-haptoglobin complex. A hemoglobin affinity purification method was used to isolate a protein of approximately 120 kDa from the hgpA hgpB double mutant. We have cloned and sequenced the gene encoding this third hemoglobin/hemoglobin-haptoglobin binding protein and designate it hgpC. Insertional mutation of hgpC did not affect the ability of the strain to utilize either hemoglobin or hemoglobin-haptoglobin. An hgpA hgpB hgpC triple mutant constructed by insertional mutagenesis showed a reduced ability to use the hemoglobin-haptoglobin complex but was unaltered in the ability to use hemoglobin. A second class of mutants was constructed in which the entire structural gene of each of the three proteins was deleted. The hgpA hgpB hgpC complete-deletion triple mutant was unable to utilize the hemoglobin-haptoglobin complex and showed a reduced ability to use hemoglobin. We have identified three hemoglobin/hemoglobin-haptoglobin-binding proteins in Haemophilus influenzae. Any one of the three proteins is sufficient to support growth with hemoglobin-haptoglobin as the heme source, and expression of at least one of the three is essential for hemoglobin-haptoglobin utilization. Although the three proteins play a role in hemoglobin utilization, an additional hemoglobin acquisition mechanism(s) exists.
Amino Acid Sequence↗
Role of CCAA nucleotide repeats in regulation of hemoglobin and hemoglobin-haptoglobin binding protein genes of Haemophilus influenzae.
Haemophilus influenzae utilizes hemoglobin and hemoglobin-haptoglobin as heme sources. The H. influenzae hemoglobin- and hemoglobin-haptoglobin binding protein genes, hgpA, hgpB, and hgpC, contain lengths of tetrameric CCAA repeats. Using an hgpA-lacZ translational gene fusion, we demonstrate phase-variable expression of lacZ associated with alteration in the length of the CCAA repeat region.
Bacterial Outer Membrane Proteins↗
Hypertension and endothelial dysfunction in apolipoprotein E knockout mice.
Mice lacking ApoE (Apoe(-/-)) develop initially hypercholesterolemia and lastly atherosclerosis. This study examined hemodynamics and endothelial function in 6-week-old Apoe(-/-) mice with hypercholesterolemia only, 7.5-months-old Apoe(-/-) mice with both hypercholesterolemia and atherosclerosis, and age matched controls. One day after implantation of catheters into the carotid artery, arterial pressure was measured in conscious, unrestrained mice. Compared with the respective controls, there was a significant increase in arterial pressure and the ratio of left ventricular weight to body weight in 7.5-month-old Apoe(-/-) mice but not in 6-week-old Apoe(-/-) mice. Histopathological analysis demonstrated significant renal artery disease in the form of extensive atheromatous plaques only in 7.5-month-old Apoe(-/-) mice, whereas no atherosclerotic lesions were found in 6-week-old Apoe(-/-) mice. For evaluation of endothelial function, a laser Doppler perfusion imager with a computer-controlled optical scanner was used to measure cutaneous blood perfusion on the dorsal side of one hind paw before and after topical application of mustard oil, which is known to induce nitric oxide-mediated vasodilation. The mustard oil treatment elicited a substantial increase in blood perfusion (P<0.01), which was similar between 6-week-old Apoe(-/-) mice and controls but significantly blunted in 7.5-month-old Apoe(-/-) mice versus control mice, suggesting nitric oxide-mediated vasodilation is diminished in 7.5-month-old Apoe(-/-) mice but not in 6-week-old Apoe(-/-) mice. In contrast, the increase in blood perfusion induced by topical administration of cilostazol, which induces vasodilation via cyclic adenosine monophosphate, was not different between 7.5-month-old Apoe(-/-) mice and controls. Thus hypertension and endothelial dysfunction observed in 7.5-month-old Apoe(-/-) mice may be due mainly to atherosclerosis.
Age Factors↗
Altered expression of bone sialoproteins in vitamin D-deficient rBSP2.7Luc transgenic mice.
Bone sialoprotein (BSP) and osteopontin (OPN) are two major noncollagenous matrix proteins in mineralized connective tissue that have discrete roles in bone matrix formation, mineralization, and remodeling. The osteotropic secosteroid, 1,25-dihydroxyvitamin D3, a potent regulator of bone remodeling required for normal bone development, has been shown to exert differential effects on OPN and BSP expression by bone cells in vitro. To investigate these effects in vivo, we induced vitamin D3 deficiency in a transgenic mouse line (rBSP2.7Luc) that has a 2.7 kb rat BSP promoter linked to a luciferase reporter gene in its genome. Pregnant rBSP2.7Luc mice were fed vitamin D3-deficient food and demineralized water for 6 weeks. Their offspring were weaned at 3 weeks of age and then fed vitamin D-deficient food for an additional week. The control group were fed normal rodent pellets and water during the entire experimental procedure. Bone tissues from 40, 4-week-old offspring in each group were analyzed for BSP, OPN and luciferase expression. Vitamin D3-deficient mice displayed a rachitic phenotype that included reduced size and malformation of bones. Assays of the BSP promoter transgene in calvariae, mandibles, and tibiae of the rachitic mice showed increases in luciferase activity of 3.1-, 1.9-, and 4.6-fold, respectively, when compared with control littermates. Semiquantitative reverse transcriptase polymerase chain reaction assays of BSP mRNA revealed increases of 7-, 74-, and 66-fold, respectively, in the same rachitic bones, while OPN mRNA was reduced 12.5-fold in calvariae and 2-fold in tibiae and mandibles. In situ hybridization using mouse cRNA probes revealed that the increased BSP expression and decreased OPN expression in the vitamin D3-deficient mice was primarily in osteoblastic cells on the surface of calvariae and endosteal spaces of alveolar bone, on newly formed epiphyseal bone, and in cementoblasts and in hypertrophic chondrocytes. These studies are the first to show that BSP and OPN are differentially regulated by vitamin D3 in vivo, reflecting the diverse roles of these protein in bone remodeling. Moreover, the increased expression of the BSP transgene in the rachitic mice demonstrates that vitamin D3 regulation of BSP expression is mediated, in part, by element(s) within the 2.7 kb promoter region.
Animals↗
A comparison of the preventive effects of lanthanides and fluoride on human experimental root surface carious-like lesions.
OBJECTIVE: To investigate the mechanisms of lanthanides prevention of human root surface carious-like lesions and to compare the effectiveness of lanthanum (La) with that of cerium (Ce) and fluoride (F). Various treatment procedures were also compared. MATERIALS AND METHODS: Acetic buffers containing lanthanum, cerium, and fluoride (500 ppm) were used individually or in combination to treat 48 cementum-dentin samples. The acid-resistant capacity of various treatment procedures was evaluated by means of scanning electron microscope, electron microprobe, and polarizing light microscope analyses. RESULTS: The acid-resistant effects of lanthanide element were comparable to those of fluoride, and their acid-resistant effects were even stronger when combined with fluoride and cerium. These effects are likely due to the formation of La(Ce)HAP, FLa(Ce)HAP, and lanthanum/cerium phosphate compounds. CONCLUSION: Combined F/La(Ce) was more effective in the prevention of root surface caries than were lanthanides alone.
Acetic Acid↗
[Study on expression of apoptosis related genes in non-small cell carcinoma].
OBJECTIVE: To study the relationship between the expression of apoptosis related genes in the tissue of non-small cell lung carcinoma (NSCLC) and clinicopathology in the tumor. METHODS: The expression of bcl-2, bax, Fas and FasL were detected with immunohistochemistry method in 45 cases of NSCLC. RESULTS: 23 (51%) cases of NSCLC were bcl-2 positive, 38 (84%) were bax positive (P < 0.01), and there was no significant correlation between the expression of bcl-2 and bax protein, but a positive relationship was found between the expression of Fas and FasL (P < 0.01). The positive rate of bcl-2 expression decreased in advanced stages of NSCLC(P < 0.05), the bax expression was lower in cases with poor cell differentiation (P < 0.05), and the FasL expression was higher in adenocarcinoma (P < 0.01). The simultaneous expression of bcl-2 and bax protein was closely correlated with TNM stages (P < 0.05), the differences of bcl-2 protein expression alone in NSCLC with cell differentiation were statistically significant (P = 0.033). CONCLUSIONS: Both bcl-2, bax, Fas and FasL may involve in the regulation of apoptosis and may play an important role in the occurrence and progression of NSCLC.
Adult↗
[Blood-purification characteristics of immobilized L-asparaginase by mathematical model].
Plasma was purified by immoblized L-asparaginase column. The predicted results were in good agreement with the experimental data, which indicated that the mathematical model was suitable for the mass transfer of blood purification.
Asparaginase↗
[Preliminary examination of a LB-H2O2 substance that inhibit Neisseria gonorrhea growth].
OBJECTIVE: To study the possible mechanism of H2O2-producing lactobacilli inhibited neisseria gonorrhoeae growth. METHODS: H2O2-producing lactobacilli were coincubated with neisseria gonorrhoeae in vitro, LB+ cell were disrupted by sonication, the protein in the lactobacilli lysate was separated by filtration through different MW sizes membranes and was examined for the ability to inhibit N. gonorrhoeae catalase activity. RESULTS: When coincubation medium was at pH 5.0, there was a significant decrease in the gonococcal catalase activity, the lysates of LB+ also effectively inhibited gonococcal catalase activity. This inhibition was retained upon heating of lysate to 100 degrees C for 15 minutes but was lost with proteinase K treatment. CONCLUSIONS: The LB+ may inhibit growth of gonococci by production of catalase inhibitors.
Catalase↗
Recombinant human respiratory syncytial virus (RSV) from cDNA and construction of subgroup A and B chimeric RSV.
Infectious human respiratory syncytial virus (RSV) was produced from a cDNA clone that contains 15,222 nucleotides of RSV genome derived from the A2 strain of subgroup A. Recovery of infectious RSV from cDNA required cotransfection of only three expression plasmids encoding the nucleoprotein (N), the phosphoprotein (P), and the major polymerase protein (L). Inclusion of the M2-1 plasmid was not required in the transfection reaction and if included did not significantly increase the rescue efficiency. However, a single nucleotide substitution in the RSV leader region (C to G at position 4 in the antigenomic sense), greatly increased the amount of infectious virus recovered from cDNA. A recombinant RSVA2 virus that expresses an additional structural G protein derived from a subgroup B RSV was also obtained. Both A2 and B strain G glycoproteins were expressed in cells infected with the chimeric RSV. A chimeric RSV that expresses a heterologous subgroup antigen in a live attenuated vaccine candidate may be important for prevention of diseases associated with both RSV subgroup A and subgroup B infection.
Animals↗
Intraspinal grafting of fibroblasts genetically modified by recombinant adenoviruses.
Intracerebral or intraspinal grafting of genetically modified primary fibroblasts has been shown to enhance functional recovery in several models of CNS disease, including spinal cord injury. Most of these studies utilized retrovirus vectors. In this report, we describe in vitro conditions for genetically modifying primary fibroblasts with recombinant adenovirus vectors carrying the lacZ or green fluorescent protein (GFP) genes. As intraspinal allografts in animals immunosuppressed by cyclosporin A, the genetically modified cells survived and expressed the transgenes for at least 2 months. We conclude that recombinant adenovirus vectors are efficient and convenient tools for ex vivo gene therapy in the CNS.
Adenoviridae↗
Nucleotide sequence analysis shows that Rhopalosiphum padi virus is a member of a novel group of insect-infecting RNA viruses.
Rhopalosiphum padi virus (RhPV) is an aphid virus that has been considered a member of the Picornaviridae based on physicochemical properties. The 10,011-nt polyadenylated RNA genome of RhPV was completely sequenced. Analysis of the sequence revealed the presence of two open reading frames (ORFs). The predicted amino acid sequence of ORF1, representing the first 6600 nt of the RhPV genome, showed significant similarity to the nonstructural proteins of several plant and animal RNA viruses. Direct sequence analysis of the RhPV capsid proteins showed that ORF2, which represents the last 2900 nt, encodes the three structural proteins (28, 29, and 30 kDa). The predicted amino acid sequence of ORF2 is very similar to the corresponding regions of Drosophila C virus, Plautia stali intestine virus, and to a partial sequence from the 3' end of the cricket paralysis virus genome. The site of initiation of protein synthesis for ORF2 could not be determined from the amino acid and nucleotide sequences. ORF1 is preceded by 579 nt of noncoding RNA and the two ORFs are separated by more than 500 nt of noncoding RNA. Like picornaviruses, these regions may function to facilitate the cap-independent initiation of translation of the two ORFs. These data suggest that RhPV, Drosophila C virus, Plautia stali intestine virus, and probably cricket paralysis virus are members of a unique group of small RNA viruses that infect primarily insects.
Amino Acid Sequence↗
D1 dopamine receptor activity is not altered by a mutation in the first intracellular loop.
The first intracellular loop of the G protein-coupled receptors (GPCRs) is probably the domain that has been studied least. According to the limited data available, mutations of this region can increase, decrease or not affect receptor-G protein coupling, depending on the receptor. Melanocyte-stimulating hormone (MSH) receptors with a Ser69Leu mutation of the first intracellular loop phenotypically confer tobacco color to the coat of mice, and have constitutive activity and enhanced agonist stimulation of adenylyl cyclase. Since the human D1 dopamine receptor (D1DR) has a serine at the equivalent position, we were interested to see if this serine is involved in receptor-G protein coupling in a similar fashion. Our site-directed mutagenesis study showed that the replacement of this serine by leucine (Ser56Leu) in D1DR did not affect the ability of the receptors to bind ligand or couple to G protein.
Adenylyl Cyclases↗
Design and synthesis of monocyclic beta-lactams as mechanism-based inhibitors of human cytomegalovirus protease.
Mechanism based inhibitors of HCMV protease have been designed based on the monocyclic beta-lactam nucleus, which have been shown to acylate the viral enzyme in a time dependent manner. SAR in a series of monocyclic beta-lactam N-ureas, has defined the size and relative stereochemistry of the C-3 substituent producing a low micromolar inhibitor 17b with good aqueous stability and selectivity over the mammalian serine proteases.
Drug Stability↗
Effects of cardiotrophin-1 on haemodynamics and cardiac function in conscious rats.
Cardiotrophin-1 (CT-1), a newly discovered cytokine, has been shown to induce cardiac hypertrophy in vitro and in vivo. The present study examined the effects of CT-1 on haemodynamics and cardiac function. The measurements of haemodynamic parameters were made using in-dwelling catheters and flow probes in conscious, unrestrained rats. Intravenous administration of CT-1 caused a dose-dependent decrease in mean arterial pressure (MAP), and an increase in heart rate (HR). CT-1 (100 micrograms/kg) significantly elevated cardiac output and HR, and decreased MAP and systemic vascular resistance. Stroke volume was unaltered, suggesting that the CT-1 induced increase in cardiac output was secondary to increased HR. There was no significant difference in left ventricular maximal dP/dt between the CT-1-treated and vehicle-treated groups, suggesting that CT-1 might not induce a meaningful change in ventricular contractility. Pretreatment with intravenous N omega-nitro-L-arginine methyl ester, a specific inhibitor of nitric oxide synthase, significantly attenuated the depressor and tachycardic responses to CT-1. These results indicate that nitric oxide plays an important role in mediating the haemodynamic effects of CT-1.
Animals↗