Characterization of an in situ IFN-gamma ELISA assay which is able to detect specific peptide responses from freshly isolated splenocytes induced by DNA minigene immunization

An in situ IFN-gamma ELISA assay has been developed and optimized for both freshly isolated and peptide-restimulated splenocytes. This assay is based on the ELISPOT assay, but utilizes a soluble chromagen, making it readily adaptable to high-throughput analysis. We show that in both the primary and restimulation assays this technique is more sensitive than either a traditional supernatant ELISA or the 51Cr-release assay, in that responses are observed in the in situ ELISA that are not detectable in these other assays. On a per-cell basis, the sensitivity of the in situ ELISA is approximately one IFN-gamma secreting cell/10(4) plated cells. The in situ IFN-gamma ELISA was utilized to describe the kinetics of the IFN-gamma response to DNA vaccination with pMin.1. For freshly isolated splenocytes, the peak response for all the peptides tested was observed from 10 to 12 days after immunization, with responses seen to some peptides as early as 7 days. When a 6-day in vitro peptide restimulation step was added, responses were seen for all the peptides tested after 7 days of in vivo immunization. This data demonstrates that a single intramuscular administration of a DNA vaccine can induce T-cell responses that can be detected in freshly isolated splenocytes.

[Analysis on maternal deaths of cesarean section in Shanghai]

OBJECTIVE

To analyze the causes of maternal deaths of cesarean section and the potential risks of it.

METHODS

A retrospective study on maternal deaths of cesarean section from 1978 to 1997 was carried out.

RESULTS

(1) The rate of cesarean section in 1978-1987 was 15.55% (258,158/1,659,892), which was significantly lower than that of 29.39% (365,376/1,243,337) in 1988-1997 (P < 0.01). (2) During the 20 years there were 430 cases of maternal deaths in Shanghai. Among them, 150 cases were maternal death after cesarean section which accounted for 34.88%. (3) Maternal mortality rate of cesarean section cases was 24.05/10(5)(150/623,534) which significantly higher (P < 0.01) than that of vaginal delivery, 12.28/10(5)(280/2,279,695). The relative risk of maternal deaths in cesarean section group increased when the cesarean section rate was over 30.00%. (4) The rank order of maternal deaths of cesarean section was as follows: PIH (pregnancy induced hypertension), Cardiac diseases, embolisms, haemorrhage, hepatic diseases, and infections. (5) The relative risk of PIH death either for cesarean section or for vaginal delivery was significantly decreased in 1988-1997, compared to the former 10 years. (6) Of 150 cases of maternal deaths of cesarean section, 43 cases (28.67%) were related to the cesarean section with embolism ranking the first, haemorrage the second and infection the third.

CONCLUSIONS

In order to reduce maternal mortality of cesarean section, it is important to pay attention to (1) the prevention and treatment of PIH, heart diseases and embolisms, (2) the indications of cesarean section, (3) improvement of the quality of cesarean section, and (4) pre- and post-operational management.

[Bone mineral analysis of whole body in 292 normal subjects assessed by dual X-ray absorptiometry]

OBJECTIVE

To understand whole body bone mineral changes in normal subjects.

METHODS

Bone mineral was measured by dual X-ray absorptiometry (DXA) in 292 normal subjects aged 10-79, including 152 females and 140 males. They were divided into age-groups by decade.

RESULTS

In males, peak value ages of total bone mineral content(TBMC), total bone mineral density(TBMD), anteroposterior spine BMD(L2-4 BMD) were in the 30-39, 20-39, 20-29 age-groups respectively. In females, they were all in the 30-39 age-group. Peak values of TBMC, TBMD, L2-4BMD were higher in males than those in females. Loss of bone mineral for females was more pronounced than that for males. There was a tendency of increased BMD among the 70-79 age-group for males. Loss of L2-4 BMD was more pronounced than TBMD.

CONCLUSIONS

This study provides the normal bone mineral data of whole body for males and females, and the characteristic of changes.

[A light and scanning electron microscopic study of primary teeth in hypophosphatasia]

OBJECTIVE

To investigate the features of primary tooth structure in hypophosphatasia.

METHODS

Three primary teeth from two patients at age of 3 yr-6 month and 4 yr-2 month, who were diagnosed hypophosphatasia. The structural changes of these teeth were examined by light microscopy, polarizing microscopy and scanning electron microscopy.

RESULTS

The complete absence of cementum was a prominent feature in all the teeth, three small island-shape cementun areas were found in scanning electron microscopy. A large number of resorptions were found on the root surfaces, particularly near apical portions of roots. The main findings included disturbances of dentin mineralization, hypoplasia or aplasia of root cementum and external resorption of root dentin.

CONCLUSION

The hypoplasia or aplasia of root cementum was thought to be the prime etiological factor in the early loss of primary teeth.

[A primary clinical study of HRV analysis of nonlinear dynamics]

We observed the changes of nonlinear dynamic parameters in the patients with diabetes and old myocardial infarction with the methods of nonlinear dynamics. The results indicate that the correlation dimension of the patients with old myocardial infarction is higher than that of the normal, their Lyapunov exponent is lower than the normal's; that the correlation dimension of the patients with diabetes is also higher than that of the normal, their Lyapunov exponent is lower than the normal's; and that the values of the entropy of the two patient groups are basically identical to the entropy of the normal. Therefore the correlation dimension can indicate the changes in the function of autonomic nerve of the patients with diabetes and old myocardial infarction.

Comparison of bone mass in forearm, lumbar vertebra and hip by single and/or dual energy X-ray absorptiometry

OBJECTIVE

Bone mineral density (BMD) was measured in normal Chinese women with single X-ray absorptiometry (SXA) and dual energy X-ray absorptiometry (DEXA). These two methods were compared to evaluate the sensitivity in reflecting bone loss.

METHODS

Measurements were performed in 300 women aged 20 to approximately 79 (5 for each age). The 8mm distal, 1/4 distal, ultra distal site of the nondominant forearm were measured with SXA; the AP spine (L2-4), right femoral neck (Neck), Ward's triangle (Ward) and trochantor (Troch) were measured with DEXA. Ten women had 5 repeated measurements to evaluate the reproducibility of the equipments.

RESULTS

The BMD peak for Neck and Ward was found between age 20 to approximately 29, for ultra distal and L2-4 at age 30 to approximately 39, for 8mm distal, 1/4 distal and Troch at age 40 to approximately 49. After reaching the peak values, BMD at all sites decreased with increasing age. The highest rate of yearly loss of BMD was at 8mm distal. Results of measurement showed significant correlation between SXA and DEXA. Comparing with premenopausal women, the bone loss rate in postmenopausal women was faster and highest up to 11 to approximately 15 years and the highest rate was at the Ward.

CONCLUSION

The present study gives the normal values of BMD at seven sites for normal Chinese women. The ages of BMD peak were different at seven sites. The yearly loss of BMD was highest at 8mm distal, it seemed to be the sensitive region for bone loss with age. The postmenopausal women had highly significantly loss bone mass than the premenopausal women. Comparing with premenopause, postmenopause BMD for Ward's triangle with DEXA seemed to be most sensitive to the effect of menopause.

poc1: an Arabidopsis mutant perturbed in phytochrome signaling because of a T DNA insertion in the promoter of PIF3, a gene encoding a phytochrome-interacting bHLH protein

The phytochrome family of informational photoreceptors has a central role in regulating light-responsive gene expression, but the mechanism of intracellular signal transduction has remained elusive. In a genetic screen for T DNA-tagged Arabidopsis mutants affected in early signaling intermediates, we identified poc1 (photocurrent 1), which exhibits enhanced responsiveness to red light. This phenotype is absent in a phyB (phytochrome B) null mutant background, indicating that the poc1 mutation enhances phyB signal transduction. The T DNA insertion in poc1 was found to be located in the promoter region of PIF3, a gene encoding a basic helix-loop-helix protein. The mutant phenotype seems to result from insertion-induced overexpression of this gene in red-light-grown seedlings, consistent with PIF3 functioning as a positively acting signaling intermediate. These findings, combined with data from a separate yeast two-hybrid screen that identified PIF3 as a phytochrome-interacting factor necessary for normal signaling, provide evidence that phytochrome signal transduction may include a direct pathway to photoresponsive nuclear genes via physical interaction of the photoreceptor molecules with the potential transcriptional regulator PIF3.

Utilization of MHC class I transgenic mice for development of minigene DNA vaccines encoding multiple HLA-restricted CTL epitopes

We engineered a multiepitope DNA minigene encoding nine dominant HLA-A2.1- and A11-restricted epitopes from the polymerase, envelope, and core proteins of hepatitis B virus and HIV, together with the PADRE (pan-DR epitope) universal Th cell epitope and an endoplasmic reticulum-translocating signal sequence. Immunization of HLA transgenic mice with this construct resulted in: 1) simultaneous CTL induction against all nine CTL epitopes despite their varying MHC binding affinities; 2) CTL responses that were equivalent in magnitude to those induced against a lipopeptide known be immunogenic in humans; 3) induction of memory CTLs up to 4 mo after a single DNA injection; 4) higher epitope-specific CTL responses than immunization with DNA encoding whole protein; and 5) a correlation between the immunogenicity of DNA-encoded epitopes in vivo and the in vitro responses of specific CTL lines against minigene DNA-transfected target cells. Examination of potential variables in minigene construct design revealed that removal of the PADRE Th cell epitope or the signal sequence, and changing the position of selected epitopes, affected the magnitude and frequency of CTL responses. Our results demonstrate the simultaneous induction of broad CTL responses in vivo against multiple dominant HLA-restricted epitopes using a minigene DNA vaccine and underline the utility of HLA transgenic mice in development and optimization of vaccine constructs for human use.

[Analysis of Lyapunov exponents of heart rate variability in diabetics]

This paper presents an analysis of Lyapunov exponents of ten normal persons and ten patients with diabetes mellitus by the definition of the Lyapunov exponents, the length evolution and the area evolution. The results show that the Lyapunov exponent of diabetic is clearly lower than that of normal. It can indicate the diabetic with less number of electrocardiographic data.

[Primary study on HRV analysis of nonlinear dynamics in animal experiment]

The purpose of this study was to address the relationship between the parameters of nonlinear dynamics and functions of heart. We adopted the methods of nonlinear dynamics in observing the changes of the parameters of nonlinear dynamics under the conditions that sympathetic or parasympathetic nerve of heart exists singly as well as the coronary artery is narrowed. The results showed that in case the sympathetic or parasympathetic nerve was cut off the correlation dimension and entropy were lower than the normals, and in case the coronary artery was seriously narrowed the correlation dimension, entropy and laypunav exponent were also lower than the normals. The conclusion is that the parameters of nolinear dynamics can indicate the changes of the functions of autonomic nerve under the above conditions.

Normal changes in spinal bone mineral density in a Chinese population: assessment by quantitative computed tomography and dual-energy X-ray absorptiometry

This study was designed to determine age- and gender-based normative values for spinal bone mineral density (BMD) in a Chinese population. In addition, we compared our data with those of other countries and populations. Four hundred and forty-three healthy Chinese subjects, aged 10-79 years (189 males, mean age 46.9 years; 254 females, mean age 45.7 years) were recruited for BMD assessment. BMD was measured by quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA), including posteroanterior DXA (PA-DXA), lateral DXA (L-DXA) and midlateral DXA (mL-DXA). For both genders, BMD values peaked in the 10-19 year age group when measured by QCT, and in the 30-39 year age group when measured by PA-DXA. BMD values decreased with age after reaching peak bone density in males and females for all measurements, except for PA-DXA in males. Male BMD values by DXA tended to increase beginning with the 60-69 age group through the 70-79 age group whether by PA-DXA, or L-DXA and mL-DXA. However, male QCT data showed stable BMD values among these two older groups. Comparative results showed female QCT data were higher in the 20-39 age group and lower after the 40-49 age group compared with American females. The peak BMD value by PA-DXA in Chinese females was reached in the same age group as American and European females and was similar in magnitude (p > 0.05). However, the peak BMD value for Chinese females was reached earlier and was significantly higher than that observed in Japanese females (p < 0.001). We conclude that the age group in which the peak BMD values are reached is different depending on the technique used, as is the calculated age-related rate of bone loss. It can be speculated that such differences reflect different timing for bone maturation in cancellous and cortical bone.

[Implementing a relatively rigorous algorithm of dynamic EIT problem on the modified FEM model]

We deduced a relatively rigorous algorithm of dynamic EIT problem-general inverse algorithm, and implemented it on the computer FEM model. Images which can show the changing of the resistivity(i.e. dynamic resistivity images) were gained. Also we modified the ordinary FEM model according to the characteristic of the EIT problem and implemented the general inverse algorithm on the modified model. The ill-posed condition of the forward matrix based on the modified model was fairly improved. It can be seen from the results that the general inverse algorithm with modified FEM model is an algorithm better than the back-projection algorithm in terms of object locating, image definition, and the ability of dealing with complex object and noise.

[Anatomy of Aconitum finetianum Hand.-Mazz]

The primary xylem of plump taproot of Aconitum finetianum is the diarch with xylem in the center. In the action of the secondary structure of the herb, the meristem is first produced in the secondary phloem, then the anomalous cambium is produced in the secondary xylem forms a new and splits into anomalous structure. In the action of anomalous structure of the herb, the meristem in the secondary phloem sinks inwardly from many sites, and forms many rings with the anomalous cambium. One of these rings forms a special endodermis and the protostele turns into the schizogenous stele.

Overexpressed phytochrome C has similar photosensory specificity to phytochrome B but a distinctive capacity to enhance primary leaf expansion

Phytochrome C (phyC) is a low-abundance member of the five-membered phytochrome family of photoreceptors in Arabidopsis. Towards developing an understanding of the photosensory and physiological functions of phyC, transgenic Arabidopsis plants were generated that over-express cDNA-encoded phyC and seedling responses to continuous white, red, or far-red light (Wc, Rc or FRc, respectively) were examined. Transgenic seedlings over-expressing phyC displayed enhanced inhibition of hypocotyl elongation in Rc, but were unchanged in responsiveness to FRc relative to wild-type. These data indicate that phyC has photosensory specificity that is similar to that of phyB and thus distinct from that of phyA. phyC overexpressors with levels only 3 to 4 times the level of endogenous phyC exhibited enhanced primary leaf expansion in Wc. This is in contrast to phyA or phyB overexpressors which respectively have levels that are 500- and 100-fold that of overexpressed phyC but showed no enhancement of primary leaf expansion. Therefore, phyC may have some physiological roles that are different to those of phyA and phyB in the control of seedling responses to light signals.

[Surgical treatment in pulmonary tuberculosis with sputum long-term Mycobacterium tuberculosis positive]

OBJECTIVE

To evaluate the importance of surgical treatment in pulmonary tuberculosis with sputum long-term Mycobacterium tuberculosis positive.

METHOD

Sixty-five patients with pulmonary tuberculosis who failed antituberculosis chemotherapy received lung resection or thoracoplasty.

RESULT

Sputum negative conversion was found in sixty-three patients without recurrence during 1-3 year follow-up, while sputum positive conversion was found only in one case during the period of follow-up. Among all the patients, one died of respiratory failure after the operation, three complicated with empyema and recovered from operating again.

CONCLUSION

Surgical operation is still important for treating pulmonary tuberculosis patients with sputum long-term Mycobacterium tuberculosis positive.

[Cytogenetic study for a child patient with mental retardation and eye multiple malformation]

An cytogenetical study was carried out for a 7 years old patient with mental retardation, eye and other multiple malformation. An extra G-positive band was found in the region of 9q12. The possible relationship between this aberration and the abnormal figures was discussed.

[Intervention approach and its effect on lowering mortality of ectopic pregnancy in Shanghai]

OBJECTIVE

To explore an effective intervention approach to lower the mortality of ectopic pregnancy.

METHODS

We monitored the mortality of ectopic pregnancy during 1987-1995 in Shanghai and experts' audit, focusing on the causes of death from ectopic pregnancy and combining official administration with intervention approach in medical institutions.

RESULTS

Misdiagnosis and patient's delay to hospital were the causes of death from ectopic pregnancy. There were 523,299 live births in Shanghai from 1987 to 1989, in which 23 cases died from ectopic pregnancy, with a mortality of 4.40/100,000. After implementing the intervention approach, during 1990-1995, 14 cases of the total 625,206 nancies live birth died from ectopic pregnancy, with a mortality of 2.24/100,000, as compared the two, P < 0.05. Accordingly, ectopic pregnancy as the cause of maternal death dropped from the first leading cause to the fourth.

CONCLUSION

Intensive health care education in masses, medical staffs' awareness to ectopic pregnancy, and intervention, early hospitalization, early diagnosis and early therapy can lower the mortality of ectopic pregnancy.

[Normal spinal changes of bone mineral density in 445 individuals: assessment by quantitative computed tomography]

Spinal BMD was measured by QCT in 445 normal individuals aged 10-80 including 190 males and 255 females, which were divided into age-groups by every ten years. Statistic results showed that peak bone mass reached at 10-19 age-group for both male and female and that BMD assessed by QCT in females was not lower than that in males and BMD declined with increasing age. In females, BMD results in this study were different from those in USA. An acceleration bone loss was predominantly shown in the period after 40-49 age group. Among many factors related to bone loss, we consider that estrogen change may play a most important role for the remarkable bone loss in our country.

Expression of variants of the major surface glycoprotein of Pneumocystis carinii

Previously, we have shown that a multicopy family of related but unique genes encodes the major surface glycoprotein (MSG) of Pneumocystis carinii. To examine whether different members of this gene family are expressed by P. carinii, antisera were prepared against peptides whose sequences were determined from the deduced amino acid sequences of variants of rat-derived MSG. Immunohistochemical staining of serial sections of rat lungs of infected animals showed that at least three variants of MSG were expressed in an individual lobe, that there was a focal expression of these variants within the lung, and that the relative numbers of these foci were different. Indirect immunofluorescent staining of purified P. carinii organisms using these antisera revealed that at least three variants of MSG were present in organisms isolated from an individual rat and that both cysts and trophozoites reacted with each antiserum. A substantial difference in the fraction of organisms reacting with a specific antipeptide antiserum was seen when comparing organisms isolated from rats raised in a single colony over a period of two years as well as organisms isolated at one time point from rats raised in different colonies. This demonstration of antigenic variation in P. carinii supports the hypothesis that P. carinii utilizes such variation for evading host defense mechanisms.

Site-specific cleavage of chromosomes in vitro through Cre-lox recombination

Site-specific recombination systems are useful tools for chromosome engineering in vivo and site-specific DNA cleavage methods have applications in genome analysis and gene isolation. Here, we report a new method to fragment chromosomes in vitro using the Cre-lox site-specific recombination system. Two lox sites were targeted into the 5.7 Mb chromosomes I of Schizosaccharomyces pombe. In vitro recombination between chromosomal lox sites and exogenously provided lox oligonucleotides 'cleaved' the chromosome at the defined lox sequences. Site-specific cleavage of lox sites in the tobacco genome was also demonstrated. This recombination-based cleavage method provides a novel approach for structural and functional analyses of eukaryotic chromosomes as it allows direct isolation of chromosome regions that correspond to phenotypes revealed through Cre-lox mediated chromosome rearrangements in vivo. Moreover, recombination with end-labeled lox oligonucleotides would permit the specific end-labeling of chromosome segments to facilitate the long range mapping of chromosomes.

Intra-chromosomal rearrangements generated by Cre-lox site-specific recombination

Chromosomal rearrangements are useful genetic and breeding tools but are often difficult to detect and characterize. To more easily identify and define chromosome deletions and inversions, we have used the bacteriophage P1 Cre-lox site-specific recombination system to generate these events in plants. This involves three steps: (i) the introduction of two lox sites into one locus in a plant genome, including one site within a modified Ds transposon; (ii) Ac transposase-mediated transposition of the Ds-lox element to a new locus on the same chromosome; (iii) Cre-mediated site-specific recombination between the two lox sites that bracket a chromosome segment. We report the production of a deletion and three inversion events in tobacco. The utility of chromosomal segments bracketed by lox sites for targeted manipulation and cloning is discussed.

[The frozen bovine RPE cells release a resolvable material which can promote the proliferation of RPE cells]

3H-thymidine incorporation (as a proliferation maker) confirms that the frozen bovine RPE cells release a resolvable material which can promote the proliferation of RPE cells, and the molecular weight of the material is more than 10,000 Daltons. This result provided some new explanations about the effect and complications of ophthalmic cryotherapy related to RPE.

Does alpha 1-acid glycoprotein act as a non-functional receptor for alpha 1-adrenergic antagonists?

The ability of a variety of alpha 1-acid glycoproteins (AAG) to affect the intrinsic activity of the alpha 1-adrenergic antagonist prazosin was studied in rabbit aortic strip preparations. From these studies, the activity of AAG appears to be linked to their ability to bind the antagonist. However, a capability to bind prazosin was not the only requirement for this effect. The removal of sialic acid and partial removal of the galactose and mannose residues by periodate oxidation of human AAG all but eliminated the ability of AAG to affect the intrinsic pharmacologic activity of prazosin, although the binding of prazosin was not significantly affected. The presence of bovine AAG, a protein that has a low ability to bind prazosin, reduced the effect of human AAG on prazosin activity. Based upon these results, we propose that AAG is able to bind in the vicinity of the alpha 1-adrenoceptors, therefore extending the binding region for antagonists in such a way as to decrease the ability of the antagonist to interact with the receptor. The carbohydrate side-chains are important for the binding of AAG in the region of the adrenoceptor.

[Ocular manifestations of patients with gangliosidosis]

This paper describes the ophthalmological findings in 4 patients with gangliosidosis (GLS). The diagnosis was verified by assaying hexosaminidase A and beta-galactosidase activities with marked deficiency. The presence of a cherry-red spot at the macular region, macular degeneration and atrophy of the optic disc were the main ocular manifestations. The ocular pathological changes seen under light and electron microscopy and the inherited error of metabolism of ganglioside are discussed.

Decreased elimination of drug in the presence of alpha-1-acid glycoprotein is related to a reduced hepatocyte uptake

The mechanism by which human alpha-1-acid glycoprotein (hAAG) decreases the intrinsic clearance of prazosin was investigated in primary rat hepatocyte cultures. The intrinsic clearance, equal to the ratio of rate of drug elimination to unbound concentration, is the composite result of uptake and metabolism. From separate elimination and uptake studies we found that the ability of hAAG to decrease the intrinsic clearance of prazosin was related to decreased uptake and not to changes in metabolism. In order to identify the underlying mechanism for the observed decrease in uptake the effect of bovine alpha-1-acid glycoprotein (AAG) on prazosin intrinsic clearance and uptake was also determined. Bovine AAG, in contrast to hAAG, had neither a statistical significant effect on prazosin uptake nor on prazosin intrinsic clearance. Based upon the fact that bovine AAG has little or no ability to bind prazosin in contrast to hAAG, we hypothesize that when a AAG, capable of binding prazosin, associated with cell membranes it will retard the diffusion of drug through the cellular stagnant diffusion layer. Human serum albumin (HSA), in contrast to hAAG, did not decrease the uptake of prazosin although HSA binds prazosin and associates with hepatocytes to the same degree as hAAG. However, HSA associated with rat hepatocytes, in contrast to hAAG, appears to have an operationally reduced ability to bind prazosin suggesting that HSA may not be able to retard diffusion of prazosin to the same degree as hAAG. HSA also may release prazosin which subsequently serves to increase the active concentration of prazosin at the cell surface.

Cre recombinase-mediated site-specific recombination between plant chromosomes

We report the use of the bacteriophage P1 Cre-lox system for generating conservative site-specific recombination between tobacco chromosomes. Two constructs, one containing a promoterless hygromycin-resistance gene preceded by a lox site (lox-hpt) and the other containing a cauliflower mosaic virus 35S promoter linked to a lox sequence and the cre coding region (35S-lox-cre), were introduced separately into tobacco plants. Crosses between plants harboring either construct produced plants with the two constructs situated on different chromosomes. Plants with recombination events were identified by selecting for hygromycin resistance, a phenotype expressed upon recombination. Molecular analysis showed that these recombination events occurred specifically at the lox sites and resulted in the reciprocal exchange of flanking host DNA. Progenies of these plants showed 67-100% cotransmission of the new transgenes, 35S-lox-hpt and lox-cre, consistent with the preferential cosegregation of translocated chromosomes. These results illustrate that site-specific recombination systems can be useful tools for the large-scale manipulation of eukaryotic chromosomes in vivo.

Analysis of the replication region of a mycobacterial plasmid, pMSC262

We determined the nucleotide sequence of a DNA fragment which contains the replication region of pMSC262, a Mycobacterium scrofulaceum plasmid used to construct the Mycobacterium-Escherichia coli shuttle vector. The complete sequence of the fragment contained 2,504 bp with an overall G+C content of 69.8%. By deletion analysis, we found that the minimum length required for plasmid replication in M. bovis BCG was about 1.6 kb. Within this region, several open reading frames (ORFs) and a putative replication origin (ori) were identified by computer analysis. One of the ORFs, ORF2, which encodes a putative 28.9-kDa basic protein with characteristics of DNA-binding proteins, appeared to be involved in replication of the plasmid in BCG. By separation of ORF2 and the putative ori region, it was revealed that the relative locations of ORF2 and the putative ori region are likely important for replication in BCG. No DNA or amino acid homologies were found between this replication region and that of pAL5000, another mycobacterial plasmid used for vector plasmid construction. In addition, we found that this replicon did not lead to replication in E. coli and was compatible in BCG with pAL5000-derived vector plasmid pYUB75 (R. G. Barletta, D. D. Kim, S. B. Snapper, B. R. Bloom, and W. R. Jacobs, J., J. Gen. Microbiol. 138:23-30, 1992).

DNA sequence and transcript analysis of transposon MuA2, a regulator of Mutator transposable element activity in maize

The 4942 bp DNA sequence of Zea mays transposon MuA2 was determined. Previous evidence indicated MuA2 controls activity of the Mu1 transposon located in the mutable allele a1-mum2. MuA2 contains two large, ATG-initiated open reading frames (ORFs) of 612 and 232 codons, respectively, located on opposite strands. MuA2 produces two transcripts, each containing one of these ORFs. Four different tandem direct repeat sequences are located downstream of the 612 codon ORF. The restriction map of MuA2 is identical to that of transposon MuR1, which also is known to regulate mutability of a1-mum2. Furthermore, except for a single nucleotide, MuA2 is identical to the Mutator element Mu9.

Identification of a nodD-like gene in Frankia by direct complementation of a Rhizobium nodD-mutant

Clones from a Frankia At4 gene bank were pooled into groups and mass conjugated into a nodD mutant of Rhizobium leguminosarum bv. viciae by triparental matings. When peas were inoculated with the pooled transconjugants, nodulation was observed. A plasmid, pAt2GX containing Frankia DNA, was isolated from bacteria recovered from these nodules. This plasmid was shown to complement a nodD mutant of R. leguminosarum bv. viciae. Thus pAt2GX contains a Frankia gene that is functionally equivalent to nodD of R. leguminosarum bv. viciae.

Reduced absolute rate of myo-inositol biosynthesis of cultured bovine retinal capillary pericytes in high glucose

De novo biosynthesis of myo-inositol (MI) by permeabilized cultured bovine retinal capillary pericytes (BRCP) and feline retinal pigment epithelial cells (FRPE), grown in different concentrations of glucose, were studied. After incubation with a physiological concentration of [14C]glucose 6-phosphate (G6P), the radioactive G6P derivatives were quantitated by a single HPLC column. Based on the determined specific activity of [14C]G6P, activities of inositol 1-phosphate synthase (MI synthase) were calculated. The activity of MI synthase was reduced 48% by growing BRCP in a high-glucose medium (20 mM) in comparison with that in the normal medium (glucose 5 mM). In contrast, the de novo MI biosynthesis by FRPE was not changed with increasing concentrations of glucose in the medium. As compared with MI uptake previously studied, the synthesized MI contributes a substantial proportion of cellular MI pool in BRCP. Therefore, in BRCP growing in high glucose the reduced MI biosynthesis aggravates the low MI content resulting from the inhibited MI uptake, and thus leads to altered inositol phospholipid metabolism.

Intramural pericyte degeneration in early diabetic retinopathy study in vitro

An experimental model of diseased pericytes was established by using cultured bovine retinal capillary pericytes in high--glucose medium. The high glucose stimulated polyol pathway, reduced cellular myo-inositol content and disturbed inositol phospholipid metabolism which resulted in a decrease in inositol trisphosphate (IP3) level. The correlation of suppressed IP3 levels with reduced DNA synthesis was evident. These findings suggested the biochemical mechanism by which retinal pericytes degenerate in high glucose. To supplement myo--inositol and/or an aldose reductase inhibitor to the high--glucose medium largely reversed the suppressed IP3 level and the decreased DNA synthesis. Therefore, these two manipulations may be considered as in vitro therapy to treat sick pericytes induced by high glucose.

DNA-synthesis regulation and correlation with inositol trisphosphate levels in cultured bovine retinal capillary pericytes

Inositol phosphate (IP), inositol bisphosphate (IP2) and inositol trisphosphate (IP3) in cultured bovine retinal capillary pericytes (BRCP) were quantitated by an ion-pair reverse-phase HPLC. BRCP were grown in media with standard (5 mM) or high (30 mM) glucose, and were either labeled with myo-[2-3H]inositol (20 microCi ml-1) for 60 hr or with dual isotopes (20 microCi ml-1 myo-[2-3H]inositol and 2 microCi ml-1 [14C]glycerol) for 8 hr. In parallel, BRCP in different glucose-media were incubated with 1 microCi ml-1 [3H]thymidine for 4 hr. High glucose significantly suppressed the accumulation of [3H]label in IP, IP2 and IP3, and specifically reduced the incorporation of [14C]glycerol into inositol phospholipids, but not that of neutral lipids and other types of phospholipids. The reduced IP3 level correlated with the decrease in the incorporation of [3H]thymidine into DNA. Both the reduced IP3 formation and DNA synthesis which were induced by high glucose were significantly reversed by adding either myo-inositol or AL1576, an aldose reductase inhibitor (ARI). However, the addition of neither myo-inositol nor ARI stimulated IP3 formation and/or DNA synthesis when BRCP were grown in the standard medium (5 mM glucose). These findings indicate that myo-inositol metabolism and the polyol pathway affect inositol phospholipid-mediated pericyte division in vitro only under the high-glucose condition. These data are compatible with the hypothesis that altered inositol phospholipid metabolism accounts for the loss of pericytes in diabetic retinopathy.

Attenuation of phosphoinositidase activity and phosphatidylinositol bisphosphate level of bovine retinal capillary pericytes in high glucose

Both phosphoinositidase (PIase) and individual species of inositol phospholipid (IPL) of bovine retinal capillary pericytes (BRCP) were quantitatively determined. When glucose in growth medium was increased from 5- to 15- or 30 mM, PIase activity was attenuated to 82% or 55%, respectively. In contrast, when glucose (5-, 15-, 30 mM) was added to an enzyme extract from cells grown in the standard growth medium (5 mM glucose, 0.04 mM myo-inositol) the PIase activity was not changed, indicating that the reduced PIase activity was not due to the direct effect of glucose. When IPLs from BRCP were analysed by HPLC and TLC, we observed reduction of the total and newly formed IPLs including the substrate of PIase. Phosphatidylinositol bisphosphate (PIP2). Reduced levels of IPLs were associated with a decrease in myo-inositol and an increase in sorbitol. The changes in IPL metabolism were reversed by adding either free myo-inositol or AL1576, an aldose reductase inhibitor (ARI), to the high-glucose medium. However, the addition of myo-inositol to the growth medium with a standard concentration of glucose only caused a marked increase in phosphatidylinositol, but not in PIP or PIP2, while the supplement of AL1576 in the standard medium did not cause any changes in IPL formation. These findings suggest that the alteration in IPL metabolism in BRCP may be related to insufficient myo-inositol or activated sorbitol pathway under high-glucose conditions. Further explanation of the role of the altered hydrolysis of PIP2 triggered by PIase may provide clues to understanding of the mechanism of decreased pericyte viability in the presence of high glucose concentrations.

Isolation and characterization of recombinant Escherichia coli clones secreting a 24-kilodalton antigen of Treponema pallidum

Escherichia coli clones containing Treponema pallidum DNA in the pUC8 vector and secreting a 24-kilodalton antigen of T. pallidum have been isolated. Both syphilitic human and syphilis-immune rabbit sera reacted with the recombinant p24 antigen, indicating that an equivalent protein in T. pallidum is capable of eliciting antibody responses during natural infections. The p24 antigen of T. pallidum was identified by using two-dimensional gel electrophoresis and immunoblotting with monospecific anti-p24 serum. We tentatively concluded that this cloned antigen is a secreted protein or a labile or minor component of T. pallidum because (i) p24 was secreted by the recombinant E. coli cells; (ii) recombinant p24 in E. coli cells was processed into several smaller species with molecular masses ranging from 12 to 20 kilodaltons, which correlate well with the masses of secreted antigens described by others; and (iii) p24 protein appeared to be highly antigenic during natural infections, but only a very small amount of this antigen was associated with or retained by the purified organisms. The possible role of the p24 protein in determining the growth characteristics of T. pallidum is suggested by the ability of recombinant p24 to induce growth changes in E. coli cells. All E. coli colonies expressing the p24 polypeptide exhibited a flat and rough colony morphology and a filamentous growth pattern that were different from those of other E. coli cells. The DNA sequence coding for the p24 polypeptide is located on a 1.7-kilobase-pair BamHI fragment of the T. pallidum genomic DNA and is absent in the nonpathogenic Treponema phagedenis DNA. However, any possible relationship between the p24 antigen and the virulence of T. pallidum remains to be determined. In preliminary studies, rabbits immunized with the purified p24 were not protected from the infection with live T. pallidum organisms.

Reduction of inositol triphosphate in retinal microvessels by glucose and restimulation by myo-inositol

The formation of inositol phospholipids (IPLs) and inositol phosphate esters (IPEs) in response to glucose was studied in isolated retinal microvessels from porcine eyes. Retinal microvessels incubated from 60 hr with myo-[3H]inositol were sequentially extracted to obtain IPLs and IPEs. [3H]Inositol-labelled IPLs were deacylated to produce the corresponding glycero derivatives. Both deacylation products and water-soluble IPEs were monitored by anion-exchange chromatography. In the presence of high glucose (30 mM) the labelling in inositol triphosphate (IP3) was reduced to 77% and was restimulated by adding myo-inositol (final concentration 0.4 mM) to 158% of the control under physiological conditions of glucose (5 mM) and myo-inositol (0.04 mM). With a fixed glucose concentration (5 mM), IPE accumulation was observed with increasing concentrations of exogenous myo-inositol. Under physiological conditions (glucose 5 mM, myo-inositol 0.04 mM) the distribution (percentage) of radioactivity in phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-phosphate (PIP2) was 63:19:18. The myo-inositol concentration dependence of IPL formation was also demonstrated. A decrease in IP3 in response to high glucose without changing PIP2 but with a reduction in PI indicated that PI may act as a reservoir to replace a possible loss of PIP2. These findings suggest that availability of myo-inositol by retinal microvessels may be essential to maintain the normal signal transduction and cell proliferation associated with IPL turnover under high glucose concentration.

Recent advances in anther culture of Hevea brasiliensis (Muell.-Arg.)

The yield of pollen embryoids from cultured Hevea anthers was increased 4 fold by optimizing the proportion of ammonium nitrate to potassium nitrate in the dedifferentiation medium. For optimal differentiation of pollen embryoids, kinetin, 2,4-D and α-naphtalene acetic acid are required. Anther culture for 50 days on the dedifferentiation medium is a prerequisite for the selective development of calli and embryoids from microspores.The determination of chromosome numbers in embryoids, plantlets and regenerated trees reveals that they originate from (poly)haploid pollen grains (n=2x=18). Aneuploid, triploid (3x=27) and tetraploid (4x=36) cells were encountered in increasing frequencies as the embryoids and plants developed. A few haploid cells with 9 chromosomes were consistently observed. Buds from shoots with mixoploid chromosome numbers can be grafted and the change in the chromosome constitution of the developing new shoots followed.