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L F Wang

Publications and source records attributed to L F Wang.

At least 181 records · Page 10Linked to original sources
PubMed1986

Isolation and characterization of a rabbit sperm tail protein.

Rabbit sperm tails were obtained by a nitrogen cavitation procedure and separated by discontinuous sucrose gradient centrifugation. Proteins were extracted from sperm tails with 3[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate (CHAPS) and separative disk electrophoresis and DEAE-trisacryl column chromatography. A protein with an estimated mol wt of 20.1 +/- 1.1 kD was isolated and found to be homogeneous by SDS-PAGE and designated as rSMP-B. The isoelectric point of rSMP-B was in the range of pH 4.4-4.7. The amino acid composition was determined, and glycine was identified as the N-terminal residue. Antisera were raised against purified rSMP-B. Using a peroxidase-antiperoxidase method, the rSMP-B antigen was located on the surface of the midpiece and tail of the sperm. Testis sections showed intense staining of late spermatids located within the seminiferous tubules. Adult male rabbits were inoculated with rSMP-B protein and Freund's adjuvant. The testis and epididymis of the immunized animals showed absence of sperm. The immunolocalization findings and the immunization data suggest that rSMP-B is formed in late spermatid and that it is an essential structural component of sperm.

Amino Acids↗
PubMed1985

A strong sequence homology exists between the major RNA polymerase sigma factors of Bacillus subtilis and Escherichia coli.

The Bacillus subtilis rpoD gene has been sequenced and the primary structure of its product deduced. The molecular weight calculated for the sigma 43 is 42,828. The DNA and protein sequences of sigma 43 exhibit extensive homology to the Escherichia coli rpoD gene and its sigma 70 product, especially in the C-terminal two-thirds of the sequence. Other proteins exhibiting partial homology with sigma 43 include the E. coli nusA protein, the E. coli htpR (heat-shock regulatory gene) product sigma 32, and specific DNA-binding proteins. No amino acid homology was found between sigma 43 and B. subtilis phage SP01 sigma gp28, phage T7 RNA polymerase, or E. coli DNA primase. The gene exhibits a strong ribosomal binding site and a typical rho-independent transcription terminator sequence. A typical transcription terminator sequence was not observed upstream from the sigma 43 gene. The sigma 43 gene may be part of an operon, resembling the situation found in the E. coli sigma operon.

Amino Acid Sequence↗
PubMed1985

Bacillus subtilis dnaE encodes a protein homologous to DNA primase of Escherichia coli.

Bacillus subtilis dnaE encodes a protein essential for DNA replication and is tightly linked to rpoD, the gene for the major sigma factor of RNA polymerase. We have now determined the 1809-base pair sequence of the dnaE coding region, which precedes rpoD and is transcribed in the same counterclockwise direction on the chromosome. From the DNA sequence, we found that the dnaE protein comprised 603 amino acids with a calculated molecular mass of 68,428 daltons. This protein had significant and extensive regions of homology with Escherichia coli DNA primase, the polymerase that synthesizes short RNA primers during discontinuous DNA replication. Features of the coding and flanking regions that may modulate dnaE expression include a relatively weak ribosomal binding site (delta G' = -13.8 kcal), the use of uncommon codons in the reading frame, and no obvious promoter sequence for either dnaE or rpoD. Together, these results suggest that dnaE codes for B. subtilis DNA primase and, in light of the similarities to the organization of the E. coli sigma operon, that expression of dnaE may be coregulated with rpoD in B. subtilis.

Amino Acid Sequence↗
PubMed1985

Catabolite-resistant sporulation (crsA) mutations in the Bacillus subtilis RNA polymerase sigma 43 gene (rpoD) can suppress and be suppressed by mutations in spo0 genes.

The catabolite-resistant sporulation (crsA) mutation is able to overcome the repressive effect of glucose on sporulation in Bacillus subtilis. Three chromosomal crsA mutations, crsA1, crsA4, and crsA47, were transferred by the "gene conversion" process to B. subtilis plasmid pRPD11, which consists of the entire wild-type rpoD coding sequence, encoding the major sigma 43 factor of B. subtilis RNA polymerase, and pUB110. By DNA sequence analysis we showed that all three crsA mutations were identical two-base changes, CCT (proline) to TTT (phenylalanine), within the rpoD coding sequence. Furthermore, the crsA47 mutation restored spo0J and spo0K sporulation to wild-type levels and partially improved the sporulation efficiencies of spo0B, spo0D, and spo0F. Extragenic suppressors (scr) of crsA47 included mutations in spo0A, spo0D, spo0F, and spo0K plus other mutations that have not been specifically identified. Thus sigma 43 appears to be involved in catabolite repression by glucose, to interact either directly or indirectly with spo0 gene products, and to play an important role in the initiation of spore development in B. subtilis.

Bacillus subtilis↗
PubMed1985

Frequencies of ceruloplasmin alleles in a Chinese population.

Plasma ceruloplasmin phenotypes were determined in a Chinese population. Among 1,042 unrelated persons examined, 3 appeared to be heterozygotes for an unidentified allele. Thus the frequency of the rare ceruloplasmin allele was estimated to be 0.0014.

Alleles↗
PubMed1984

Immunolocalization of a sperm membrane protein in human male reproductive organs.

A monoclonal antibody that induces agglutination of human sperm was used to localize the interacting antigen in various tissues by indirect immunofluorescence. The antibody localized to the immature sperm and Sertoli cells of the seminiferous tubules, simple cuboidal epithelial cells of the rete testis, and the columnar epithelial cells of the ductuli efferentes. The present results show that the interacting protein is found associated with germ cells undergoing spermatogenesis.

Animals↗
PubMed1983

Types and subtypes of haptoglobin in the Chinese population.

Haptoglobin phenotypes of 1121 unrelated Chinese blood donors in Beijing were determined. The gene frequency of Hp1 was 0.270. A rare variant, which we identified as Hp1S-J, was found. Two hundred and two samples of this population were submitted to haptoglobin subtyping, and no Hp1F allele was found among them.

Blood Donors↗
PubMed1981

The gene frequency of serum albumin variants in Chinese and the electrophoretic characterization of several serum albumin variants.

By screening a Chinese population of 1025 unrelated persons in Beijing, three serum albumin variants were discovered, and the gene frequency of serum albumin variants of Chinese is estimated as 0.0015. These albumin variants can be distinguished electrophoretically from each other, and were named tentatively as albumin Hanzhong, albumin Changzhi and albumin LXX respectively. A polyacrylamide gel electrophoresis procedure has been developed to characterize albumin variants by determining the relative mobilities (Rm) of albumin variants in a tris-succinate buffer system.

Asian People↗