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Biomedical subjects

Z Cheng

Publications and source records attributed to Z Cheng.

160 records · Page 9Linked to original sources
PubMed1989

[Morphological study of Omsk hemorrhagic fever (OHF) virus with the electron microscope].

Morphological characterization of OHF virus was studied by means of thin section electron microscopy in the brains of mice infected with Omsk hemorrhagic fever virus. The crystals, microvesicles, vacuoles and as beehive structures were observed in the virus-infected cells. The possible relationship between the characteristic structures and virus morphogenesis is discussed. It is indicated that these characteristic structures may be important to morphological characterization of OHF virus.

Animals↗
PubMed1988

Randomly picked cosmid clones overlap the pyrB and oriC gap in the physical map of the E. coli chromosome.

Sets of overlapping cosmid clones generated by random sampling and fingerprinting methods complement data at pyrB (96.5') and oriC (84') in the published physical map of E. coli. A new cloning strategy using sheared DNA, and a low copy, inducible cosmid vector were used in order to reduce bias in libraries, in conjunction with micro-methods for preparing cosmid DNA from a large number of clones. Our results are relevant to the design of the best approach to the physical mapping of large genomes.

Chromosome Mapping↗
PubMed1988

Beta-endorphin-like immunoreactivity increases in cerebrospinal fluid of acute head-injured patients.

beta-endorphin-like immunoreactivity (beta-ELI) was measured in cerebrospinal fluid (CSF) of 36 acute head-injured patients and 12 patients without head injury as controls. The mean level of beta-ELI in CSF of controls, mild cerebral contusions, and severe cerebral contusion patients were 51.9 +/- 5.6 pg/ml, 110.5 +/- 14.5 pg/ml, and 173.8 +/- 20.1 pg/ml respectively, with significant difference between them. The results also showed that beta-ELI may reflect the prognosis of acute head-injured patients.

Brain Injuries↗
PubMedDate not supplied

Protein tyrosine phosphatase SHP-1 specifically recognizes C-terminal residues of its substrates via helix alpha0.

The catalytic domain of protein tyrosine phosphatase SHP-1 possesses distinct substrate specificity. It recognizes the P-3 to P-5 residues of its substrates via the beta5-loop-beta6 region. To study the substrate specificity further, we determined the structure of the catalytic domain of SHP-1 (C455S) complexed with a less-favorable-substrate peptide originated from SIRPalpha. The complex has disordered N-terminal peptide structure and reduced interactions between the N-terminal peptide and the beta5-loop-beta6 region. This could be the basis for the lower affinity of peptide pY(427) for the catalytic domain of SHP-1. In addition, by comparing the SHP-1/less-favorable peptide complex structure with the SHP-1/substrate complex structures, we identified a novel substrate-recognition site in the catalytic domain of SHP-1. This site was formed by helix alpha0 and the alpha5-loop-alpha6 motif of SHP-1, and specifically bound residues at the P + 4 and further C-terminal positions of peptide substrates.

Binding Sites↗
PubMedDate not supplied

Electroretinographic measures of vision in horseshoe crabs with uniform versus variegated carapaces.

The carapace characteristics of horseshoe crabs (Limulus polyphemus) have been correlated by others with male mating performance and it has also been suggested that such mating differences might depend on visual differences. The effect of carapace character on horseshoe crab vision was therefore noninvasively investigated using the electroretinogram (ERG) of the lateral compound eye as a measure. Male Limulus were dichotomized on three carapace dimensions: clear versus dark eyes, light versus dark carapaces, and presence versus absence of barnacles. All dichotomizations gave similar results: No crab was ERG-blind. Analyses based on ERG magnitude yielded trivial sensitivity differences between these groups. However, analyses based on ERG latency indicated that response speeds exhibited reliably different trends between groups: Although responses to dim flashes were similar for all animals, increasing flash intensity produced significantly greater changes in the latencies of the ERGs in uniform males than in variegated males. This interactive dependence of ERG speed differences on flash energy cannot be the result of greater light absorption by the variegated specimens' darkened corneas. The visual capacities of variegated specimens are therefore somewhat altered, but certainly not absent. Equalizing animal size between groups did not measurably affect these results, implying that age was not a factor. The previously reported correlation of an individual male's appearance with its performance in mating competitions is extended by these data to include its sensory functioning as well.

Animals↗