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Z Pang

Publications and source records attributed to Z Pang.

32 records · Page 2Linked to original sources
PubMed1996

Ginkgo biloba L.: history, current status, and future prospects.

In this paper, we describe the status of the exploration and use of the Ginkgo biloba leaves in China. We emphasize the need for careful studies of the intra-specific genetic diversity of Ginkgo biloba since genetic variation within this species may result in significant differences between the chemical and pharmacological properties of the different sub-species. It is therefore imperative that we catalog the intraspecific diversity of Ginkgo biloba L., and we stress that it is important to conserve this diversity since different subspecies may have different pharmacochemical properties resulting in differential medical usages.

Cycadopsida↗
PubMed1994

Structure of the nucleocapsid protein gene of rice yellow stunt rhabdovirus.

The complete nucleotide sequence of the N protein gene of rice yellow stunt rhabdovirus (RYSV) was determined by sequencing of cDNA clones derived from the viral genomic RNA. The 3' end of the N gene (messenger sense) was defined by sequence analysis of cDNA clones generated from the N protein mRNA by 3'RACE. The 5' end sequence of the gene was putatively assigned as 5'-AACAC-3'; this sequence is found in the presumed 3' leader/N gene junction region. The mRNA encoding the RYSV N protein is 1714 nt comprising a 15-nt untranslated 5' leader sequence followed by an open reading frame (ORF) of 1563 nt and a 136-nt untranslated 3' region. The calculated molecular mass of the N protein encoded by the ORF is 58,400 Da, which is larger in size than N proteins of other rhabdoviruses. Amino acid composition analysis shows that the RYSV N protein is rather basic with a predicted isoelectric point of 10.04; indeed, a large highly basic region could be found at the carboxy terminal portion of the protein. Amino acid sequence comparison between N proteins of RYSV and sonchus yellow net virus, both of which belong to the same genus Nucleorhabdovirus, revealed an overall 30% identity, with three relatively conserved blocks of 14-20 amino acid residues. Moreover, the hydropathy profiles of the two proteins are generally similar. The structural similarities between the N protein of RYSV and that of lettuce necrotic yellows virus, the type member of the genus Cytorhabdovirus, and those of animal rhabdoviruses, are less significant. Nucleotide sequence determination of 5' and 3' regions flanking the RYSV N gene identified a 14-nt common sequence that is very similar to the consensus gene junction sequences of other plant and animal rhabdoviruses.

Amino Acid Sequence↗
PubMed1994

Black-ear gene and blood polymorphism in four southern Chinese cattle groups.

The gene for black-ear coat colour pattern, commonly found among cattle of tropical origin, was observed in 809 animals of four breeds of local cattle in southern China. Gene frequencies for Tf, Hb and Alb demonstrated that these groups of cattle were quite divergent from Bos taurus. These breeds of cattle are thought to be descended from ancient Chinese cattle. At the same time certain influences observed in coat colour may be derived from Bali cattle.

Animals↗
PubMed1991

Retinoblastoma protein and simian virus 40-dependent immortalization of human fibroblasts.

Transformation and immortalization of human diploid fibroblasts by simian virus 40 (SV40) is at least a two-stage process, since transformants have a limited lifespan in culture. We have isolated immortalized derivatives (AR5 and HAL) from transformants generated with an origin-defective SV40 genome encoding a heat-labile large T protein (T antigen) and reported that both preimmortal and immortal transformants are continuously dependent on T antigen function for growth as determined by temperature shift experiments. In this study, we demonstrate complex formation between T antigen and the retinoblastoma susceptibility gene product (Rb) at 35 degrees C and observed a reduction in complexes under conditions of loss of T antigen function and growth inhibition at 39 degrees C. Viral oncogenes (polyomavirus large T protein and adenovirus E1A 12S protein) known to bind Rb were introduced into AR5 and HAL cells, both stably by gene transfer and transiently by virus vectors. Such double transformants are still unable to proliferate at 39 degrees C, although complex formation with the newly introduced oncogenes was demonstrated. We suggest that T antigen interacts with other cellular processes in addition to Rb to transform and immortalize human cells in culture. Our finding that p53-T antigen complexes are also temperature dependent in AR5 and HAL cells could provide such an additional mechanism.

Antigens, Viral, Tumor↗
PubMed1991

[Effect of triiodothyronine on the expression of neuron-specific enolase activity in developing cultured human fetal cerebral neurons].

Culture of human fetal cerebral neurons in serum-free medium was established. The enolase isoenzymes in the cultured neurons were fractionated by DEAE cellulose ion exchange chromatography. The total enolase activity was resolved into three peaks: Non-neuronal enolase (NNE or alpha alpha and alpha gamma) appeared in 10-day cultures, and the peak of neuron -specific enolase (NSE or gamma gamma) in the group added T3 appeared earlier (in 15-day cultures) than in the control group (20-day cultures). The percentage of gamma gamma enolase activity in the group added T3 was 2.55 times higher than that in the control group. In conclusion, the present study demonstrated that T3 in physiological concentration may promote the differentiation and maturation of neurons in cultures, verifying the expression of NSE and the switch-over of NNE (alpha alpha, alpha gamma) to NSE (gamma gamma).

Brain↗
PubMed1991

[Fluorescent determination of magnolol by surfaceactive emulsifier].

Fluorescent determination of magnolol has been effected employing the sensitivity- and stability-enhancing action of the non-ionic surfaceactive emulsifier OP. As a result the accuracy of determination is raised by 2 orders of magnitude as compared to that of ultraviolet spectrophotometry.

Biphenyl Compounds↗
PubMedDate not supplied

Hippocampal damage and cytoskeletal disruption resulting from impaired energy metabolism. Implications for Alzheimer disease.

To determine if impaired energy metabolism might contribute to some aspects of Alzheimer disease (AD), including the vulnerability of the CA1 region of the hippocampal formation and the altered cytoskeleton evident in neurofibrillary tangles, we examined the effects of metabolic poisons on neuronal damage and cytoskeletal disruption in the hippocampal formation. Intrahippocampal injection of 3-nitropropionic acid (3-NP) and malonic acid resulted in neuronal death, particularly in CA1. Cytoskeletal disruption included loss of dendritic MAP2, but sparing of axonal gamma. MK-801 (a noncompetitive NMDA receptor antagonist) did not atentuate the lesions produced by intrahippocampal injection of malonate. MK-801, however, was effective against intrastriatal malonate. Acute systemic 3-NP resulted in neuronal damage and cytoskeletal disruption in the CA1 region of the hippocampal formation, including an extensive loss of MAP2 immuno-reactivity, but sparing of gamma. The neuronal loss in CA1 was delayed as compared to striatum. Chronic intraventricular infusion of 3-NP produced a different pattern of neuronal damage. Loss of gamma-1 immuno-reactivity was observed in CA3 and CA1 s. orients, whereas MAP2 immunostaining was preserved. These results demonstrate that chronic and acute administration of metabolic inhibitors produce distinct patterns of neuronal damage and cytoskeletal disruption. The results further suggest a differential involvement of the NMDA receptor in malonate-induced neuronal damage in striatum as compared to the hippocampus. The pattern of neuronal damage and cytoskeletal disruption observed following acute metabolic impairment resembled some aspects of neurofibrillary pathology in AD, but did not result in gamma hyperphosphorylation.

Alzheimer Disease↗
PubMedDate not supplied

Perikaryal accumulation and proteolysis of neurofilament proteins in the post-mortem rat brain.

Investigations of neurofilament alterations in neurodegenerative disorders utilize postmortem human tissues obtained at autopsy. To determine if alterations in the levels or distribution of neurofilament proteins might occur during the interval between death and autopsy, the postmortem cooling curve of the human brain was modeled in Sprague-Dawley rats and neurofilament proteins were examined by immunocytochemistry and immunoblots. One hour after death, enhanced perikaryal immunostaining of NF-M and both phosphorylated and nonphosphorylated NF-H epitopes was observed throughout the hippocampal formation. A greater number of neurons exhibited increased somatic immunostaining 4-h postmortem. In addition, loss of neurofilament protein immunostaining was observed in the neuropil, particularly in the molecular layer of the dentate gyrus. This corresponded with, but lagged behind, the pattern of calpain activation determined using an antibody against calpain-cleaved alpha-spectrin. Immunoblots confirmed the postmortem loss of neurofilament proteins in both triton-soluble and insoluble fractions. These results demonstrate that the levels and localization of neurofilament proteins observed in tissues obtained at autopsy even with short postmortem intervals may not accurately reflect the premortem condition.

Analysis of Variance↗
PubMedDate not supplied

SV40-mediated immortalization of human fibroblasts.

We have identified a multistep mechanism by which the DNA virus SV40 overcomes cellular senescence. Expression of SV40 T antigen is required for both transient extension of life span and unlimited life span or immortalization. These effects are mediated through inactivation of function of growth suppressors pRB and p53 via complex formation with T antigen. However, immortalization additionally requires inactivation of a novel growth suppressor gene, which has recently been identified to be on the distal portion of the long arm of chromosome 6, designated SEN6. We propose that SEN6 is responsible for cellular senescence in fibroblasts and other cells.

Antigens, Polyomavirus Transforming↗