Very low density lipoprotein and oxidized very low density lipoprotein induce monocyte chemotactic protein 1 in rabbit aortic smooth muscle cells

OBJECTIVE

To understand whether very low density lipoprotein (VLDL) and oxidatively modified very low density lipoprotein (OX-VLDL) can stimulate vascular smooth muscle cells (SMCs) to express high level of monocyte chemotactic protein (MCP-1) mRNA.

METHODS

LDL and VLDL were isolated from normal blood donors by density gradient ultracentrifugation and oxidatively modified by adding CuCl2 and incubation at 37 degrees C for 24 hours. Rabbit aortic SMCs were cultured by a substrate-attached explant method, and their total RNA was extracted by guanidinium isothiocyanate method. The expression of MCP-1 mRNA in SMCs was examined by dot blotting analysis using a probe of gamma-22P-end-labeled 35-mer oligonucleotide.

RESULTS

Dot blotting analysis showed that cultured SMCs can express MCP-1 mRNA and the level of MCP-1 mRNA was increased significantly in SMCs after 24-hour coculture with VLDL (6-fold) and OX-VLDL (20-fold).

CONCLUSIONS

VLDL and OX-VLDL both can induce MCP-1 mRNA expression in cultured rabbit aortic SMCs and the latter is more effective than the former.

Partial purification of smooth muscle cell derived growth factor

The serum free medium conditioned by cultured rabbit aortic smooth muscle cells was partially purified using ultrafiltration and heparin affinity chromatography. Incorporation of [3H]-thymidine (3H-TdR) into cell DNA was used to measure the mitogenic activity of the fractions from chromatography for NIH 3T3 fibroblasts. The molecular weight and the iso-electric point of these fractions were determined by NaDodSO4-polyacrylamide gel electrophoresis (SDS-PAGE) and iso-electric focusing, respectively. The results showed that the protein eluted in 1.0-1.6 mol/L NaCl from the heparin-Sepharose was mitogenic for 3T3 cells, and this protein had a molecular weight of 22.8-26.7 ku and an iso-electric point of about 4.6. The fact that the above-mentioned biochemical properties differed from that of PDGF, IGF and FGF suggests that this mitogenic protein may be a separate growth factor.

Detection of Borrelia burgdorferi-specific antigen in antibody-negative cerebrospinal fluid in neurologic Lyme disease

OBJECTIVE

To determine the potential of detection in CSF of specific Borrelia burgdorferi antigen, OspA, as a marker of infection in neurologic Lyme disease and compare this with the detection of antibody.

DESIGN

CSF from 83 neurologic patients in an area highly endemic for Lyme disease was examined prospectively for (1) OspA by antigen capture ELISA and Western blot employing monoclonal antibodies, and for (2) B burgdorferi antibodies by ELISA.

RESULTS

Of the 35 of 83 (42%) patients who were positive for OspA antigen in their CSF, 15 (43%) were antigen positive despite being antibody-negative in CSF. Seven of these 15 (47%) had otherwise normal routine CSF analyses. Six of these 15 (40%) patients met strict CDC surveillance criteria for Lyme disease; four (27%) patients had seroconversion coincident with new neurologic problems; and three (20%) with characteristic syndromes for Lyme disease were seronegative, but had complexed antibody to B burgdorferi. The final two patients (13%) were seropositive and had unexplained neurologic problems not characteristic of Lyme disease.

CONCLUSIONS

B burgdorferi antigen can be detected in CSF that is otherwise normal by conventional methodology, and can be present without positive CSF antibody. Since CSF antigen implies intrathecal seeding of the infection, the diagnosis of neurologic infection by B burgdorferi should not be excluded solely on the basis of normal routine CSF or negative CSF antibody analyses.

Investigation of high-resolution angle sensing with laser mode-split technology

We present a new method of angular measurement, which is to rotate a 15-mm-diameter, 3-mm-thick crystal quartz plate in a He-Ne laser cavity to produce a laser mode split. The magnitude of the mode split (in hertz) represents the angle of rotation. The experimental devices used are described. The stability of the beat frequency is 0.78 kHz (1σ). A sensitivity of 2.62 3 × 10(4) Hz/", where" is angular seconds, has been reached and the repeatability is 0.3". The principal error factors are discussed.

Mapping of two phenol sulphotransferase genes, STP and STM, to 16p: candidate genes for Batten disease

The cytosolic phenol sulphotransferase gene (STP) was mapped to a region of chromosome 16, within the interval defined by human-rodent somatic cell hybrid breakpoints CY160(D) and CY12, which contains FRA16E. YAC and cosmid clones from this 16p interval were screened for the presence of STP. Two non-overlapping cosmid contigs were identified which contain STP-like sequences. Sequencing of these STP-like sequences confirmed that STP is contained within contig 343.1 and maps proximal to FRA16E, and that a related sulphotransferase STM, encoding the catecholamine-sulphating enzyme, is contained within contig 55.4 and maps to the adjacent hybrid interval CY12-CY180A. Thus two phenol sulphotransferase genes (STP and STM) have been finely localised to chromosome 16p12.1-p11.2, to the same region as CLN3, the gene for Batten disease. Both genes are therefore candidate genes for Batten disease.

Repeated polyketide synthase modules involved in the biosynthesis of a heptaene macrolide by Streptomyces sp. FR-008

Genes for biosynthesis of a Streptomyces sp. FR-008 heptaene macrolide antibiotic with antifungal and mosquito larvicidal activity were cloned in Escherichia coli using heterologous DNA probes. The cloned genes were implicated in heptaene biosynthesis by gene replacement. The FR-008 antibiotic contains a 38-membered, polyketide-derived macrolide ring. Southern hybridization using probes encoding domains of the type I modular erythromycin polyketide synthase (PKS) showed that the Streptomyces sp. FR-008 PKS gene cluster contains repeated sequences spanning c. 105kb of contiguous DNA; assuming c. 5 kb for each PKS module, this is in striking agreement with the expectation for the 21-step condensation process required for synthesis of the FR-008 carbon chain. The methods developed for transformation and gene replacement in Streptomyces sp. FR-008 make it possible to genetically manipulate polyene macrolide production, and may later lead to the biosynthesis of novel polyene macrolides.

Molecular cloning of the human nucleotide-excision-repair gene ERCC4

ERCC4 was previously identified in somatic cell hybrids as a human gene that corrects the nucleotide-excision-repair deficiency in mutant hamster cells. The cloning strategy for ERCC4 involved transfection of the repair-deficient hamster cell line UV41 with a human sCos-1 cosmid library derived from chromosome 16. Enhanced UV resistance was seen with one cosmid-library transformant and two secondary transformants of UV41. Cosmid clones carrying a functional ERCC4 gene were isolated from a library of a secondary transformant by selecting in Escherichia coli for expression of a linked neomycin-resistance gene that was present in the sCos-1 vector. The cosmids mapped to 16p13.13-p13.2, the location assigned to ERCC4 by using somatic cell hybrids. Upon transfection into UV41, six cosmid clones gave partial correction ranging from 30% to 64%, although all appeared to contain the complete gene. The capacity for in vitro excision of thymine dimers from a plasmid by transformant cell extracts correlated qualitatively with enhanced UV resistance.

Streptomyces lividans 66 contains a gene for phage resistance which is similar to the phage lambda ea59 endonuclease gene

The DNA of wild-type Streptomyces lividans 66 is degraded during electrophoresis in buffers containing traces of ferrous iron. S. lividans ZX1, a mutant selected for resistance to DNA degradation, simultaneously became sensitive to phi HAU3, a wide-host-range temperate bacteriophage. A DNA fragment conferring phi HAU3 resistance was cloned; it contains a phage resistance gene whose deduced amino acid sequence is similar to the phage lambda Ea59 endonuclease. The S. lividans phi HAU3 resistance does not seem to be a classical restriction-modification system, because no host-modified phages able to propagate on the wild-type strain could be isolated. The cloned fragment did not make the host DNA prone to degradation during electrophoresis, indicating that the two phenotypes are controlled by different genes which were deleted together from the chromosome of ZX1.

Characterization of phi HAU3, a broad-host-range temperate streptomyces phage, and development of phasmids

phi HAU3 is a temperate Streptomyces phage with cohesive ends and a broad host range that includes Streptomyces hygroscopicus 10-22, a producer of antifungal compounds, but it fails to grow on Streptomyces lividans 66. Two phasmid derivatives were constructed that function as lambda cosmid vectors in Escherichia coli and as phages in Streptomyces spp.

Development of a gene cloning system for Streptomyces hygroscopicus subsp. yingchengensis, a producer of three useful antifungal compounds, by elimination of three barriers to DNA transfer

Streptomyces hygroscopicus 10-22 could not be transformed with any of the commonly used Streptomyces plasmid vectors and was resistant to plaque formation by the Streptomyces phages phi C31 and R4. Repeated selection resulted in the isolation of derivatives of S. hygroscopicus 10-22 that could be transformed with pIJ101- and pJV1-derived cloning vectors and of restriction-deficient derivatives that could accept DNA propagated in Streptomyces lividans 66. These new strains, which include three that still produce the original antibiotics, can be used as hosts for gene cloning. Insertion of nonreplicating vectors by homologous recombination and transposition of Tn4560 were demonstrated in S. hygroscopicus 10-22.

Mapping of the phenol sulfotransferase gene (STP) to human chromosome 16p12.1-p11.2 and to mouse chromosome 7

We have recently cloned a cDNA encoding the human phenol-preferring phenol sulfotransferase (P-PST) enzyme. An oligonucleotide primer pair based on the human STP (representing sulfotransferase, phenol-preferring) cDNA sequence was synthesized and was employed in polymerase chain reaction (PCR) amplification of human genomic DNA to identify a 525-bp DNA fragment. The DNA sequence of this portion of the STP gene, near the 5' end of the coding region, was determined. The amplified genomic fragment contained two small introns of 104 and 89 bp. When DNA samples from a human-hamster somatic cell hybrid panel were screened by PCR using these primers, only those hybrids that contained human chromosome 16 were positive for the 525-bp genomic fragment. To identify the specific region on chromosome 16 that contained the STP gene, PCR amplification reactions were performed on a human-mouse somatic cell hybrid panel containing defined portions of human chromosome 16. The results indicated that STP is localized proximal to the gene for protein kinase C, beta 1 polypeptide (PRKCB1), in the region from the distal portion of 16p11.2 to p12.1. The human STP gene maps near the locus for Batten disease (CLN3). Furthermore, we have determined by genotyping of murine interspecific backcross progeny that the homologous gene in mouse (Stp) localizes to the syntenic region of mouse chromosome 7 near the D7Mit8 (at 54 cM) and D7Bir1 markers.

Smooth muscle myosin heavy chain locus (MYH11) maps to 16p13.13-p13.12 and establishes a new region of conserved synteny between human 16p and mouse 16

The human smooth muscle myosin heavy chain locus (MYH11) was mapped by fluorescence in situ hybridization to the middle of the p arm of chromosome 16 using a genomic cosmid clone containing coding sequences of the gene as probe. Probe from coding sequence, when applied to Southern blots of a panel of hybrids containing different portions of human chromosome 16, localized the gene to 16p13.13-13.12. Coding sequence PCR primers, when used on the DNA from a CHO-mouse hybrid clone mapping panel informative for mouse chromosomes, showed that the gene was located on mouse chromosome 16. These results correct a recent assignment of MYH11 from 16q12.2 to the region of the 16p-arm inversion breakpoint seen in acute myelomonocytic leukemia (AMML) M4Eo and demonstrate that the conflicting data do not result from the presence of additional MYH genes on the q arm of the chromosome. Also, a new region of conserved synteny between human 16p and mouse 16 is established.

Detection of Borrelia burgdorferi antigens in cerebrospinal fluid

We examined CSF for Borrelia burgdorferi antigens using antigen-capture ELISA and Western (immuno) blot. Antigen-capture ELISA was positive in 38 of 77 (49%) CSF samples obtained from neurologic patients with presumed B burgdorferi infection, compared with one of 34 (3%) CSF samples obtained from other neurologic disease controls who came from a region endemic for Lyme disease. Western immunoblot was positive for B burgdorferi antigens in 12 of 22 (55%) CSF samples from the B burgdorferi infected groups, compared with none of 11 CSF samples from the control group. CSF antigen detection should prove helpful in evaluating patients for suspected neurologic Lyme disease.

Cloning and characterization of a mouse 3-methyladenine/7-methyl-guanine/3-methylguanine DNA glycosylase cDNA whose gene maps to chromosome 11

In Escherichia coli, the repair of 3-methyladenine (3MeA) DNA lesions by DNA glycosylases prevents alkylation induced cell death. We described previously the isolation of a human 3MeA DNA glycosylase (AAG) cDNA that maps to chromosome 16 and hybridizes to specific genomic DNA fragments from a number of mammals, including mouse. As a first step in the generation of a 3MeA DNA glycosylase deficient mouse by homologous replacement in embryonic stem cells, we have cloned the mouse 3MeA DNA glycosylase cDNA. The cloned 1095 base pair cDNA contains a complete 333 amino acid open reading frame that predicts a 36.5 kDa protein and hybridizes to a 1.5 kb mRNA transcript. Mouse 3MeA DNA glycosylase (Aag) transcript levels vary by up to 21 fold among tissues, being highest in the testes and lowest in the heart. The Aag cDNA encodes a glycosylase able to release 3MeA, 7-methylguanine (7MeG) and 3-methylguanine (3MeG) from alkylated DNA. The expression of Aag in E. coli provides substantial resistance against killing by methylating agents, but, unlike its E. coli counterparts, the Aag glycosylase fails to protect against killing by ethylating and propylating agents. A 232 amino acid stretch of the predicted mouse protein shares extensive amino acid identity with rat (93%) and human (83%) 3MeA DNA glycosylases and we observe that all three mammalian glycosylases have a bipartite nuclear localization signal. The Aag gene maps to mouse chromosome 11, suggesting a segment of conserved synteny between mouse chromosome 11 and human chromosome 16, which bears the human 3MeA DNA glycosylase gene. Cloning the mouse 3MeA DNA glycosylase cDNA is a step toward understanding the role of this DNA repair enzyme in mammals.

[The growth pattern of atherosclerotic rabbit aortic smooth muscle cells in culture]

Rabbit aortic smooth muscle cells (SMCs) both from normal and atherosclerotic (AS) animals were cultured for study on their growth activities and the relation to the cell cycle kinetics. The growth activities of different cell populations were compared by measuring cell doubling time, labelling index and mitosis index. For cell cycle analysis, 3H-TdR flash labelling method was employed. The results showed that SMCs derived from atherosclerotic rabbits grew more rapidly in culture than those from normal animals, the cell doubling time in the AS group was shorter than normal, 28.8 hrs versus 40.8 hrs, while the labelling and mitosis index in the AS group were higher. SMC cell cycle analysis showed that their generation time was 9.6-9.9 hrs and there was no significant difference of the distribution of cell cycle phases and their generation time between SMCs from AS and control group. The results indicate that the increased proliferative activities of atherosclerotic SMCs are not due to the change of their cell cycle kinetics, but having more cells emerging from G0/G1 phase into S phase.

Site-specific degradation of Streptomyces lividans DNA during electrophoresis in buffers contaminated with ferrous iron

Streptomyces lividans DNA contains a modification which makes it susceptible to double-strand cleavage during electrophoresis in buffers contaminated with ferrous iron (which may be present in some batches of EDTA). The cleavage of the DNA is site-specific and the average fragment size resulting from limit digestion of total S. lividans DNA is about 6kb. DNA from Streptomyces coelicolor A3(2) and several other Streptomyces strains, and from E. coli, is not cleaved under the same conditions. A S. lividans mutant has been isolated which lacks the DNA modification. We suspect that many reports of "poor" preparations of S. lividans plasmids may be due to the above effect.

Infections caused by Penicillium marneffei in China and Southeast Asia: review of eighteen published cases and report of four more Chinese cases

One accidental and 17 natural human infections caused by Penicillium marneffei have been reported in the literature. The accidental infection, in Paris, followed inoculation of a culture from a Vietnamese bamboo rat into the finger of a mycologist. All patients with natural infections had lived or traveled in the Far East. Nine of these patients were Chinese, all from Guangxi Zhuang Autonomous Region. The four additional infections from Guangxi reported herein bring the total to 21 natural infections. P. marneffei is a primary pathogen of humans, causing two clinical types of disease: focal infection and fatal, progressive, disseminated infection. There are three histopathologic reactions: (1) granulomatous; (2) suppurative; and (3) anergic and necrotizing. The first two reactions are seen in patients with "normal" immunity and the third in patients with compromised immunity. P. marneffei is unique among species of Penicillium because of its thermal dimorphism, its recognized ecologic niche (restricted to the Far East), and its propensity to infect the lungs and the reticuloendothelial system and to proliferate within histiocytes.