mGluR1-mediated potentiation of NMDA receptors involves a rise in intracellular calcium and activation of protein kinase C

Potentiation of ionotropic glutamate receptor activity by metabotropic glutamate receptors (mGluRs) is thought to modulate activity at glutamatergic synapses in the hippocampus. However, the precise pathway by which this modulation occurs is not well understood. The present study tests the hypothesis that mGluR1-mediated potentiation of N-methyl-D-aspartate receptors (NMDARs) occurs via a phospholipase C (PLC)-initiated cascade. NMDAR functional activity was examined by whole-cell recording from Xenopus oocytes expressing recombinant NMDARs and mGluR1alpha. The mGluR1 agonist (1S,3R)-1-amino-cyclopentane-1,3-dicarboxylic acid (ACPD) significantly potentiated NMDA-elicited currents. mGluR1alpha-mediated potentiation of NMDA responses was eliminated by the PLC inhibitor U-73122. Buffering of intracellular Ca2+ by BAPTA-AM or depletion of intracellular Ca2+ by the Ca2+/ATPase inhibitor thapsigargin greatly reduced ACPD potentiation. ACPD potentiation was reduced by the specific protein kinase C (PKC) inhibitor Ro-32-0432 and eliminated by the broad spectrum kinase inhibitor staurosporine. ACPD produced no further potentiation after potentiation of NMDARs by the PKC-activating phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA). Thus, Group I mGluRs potentiate NMDA responses via activation of PLC; at least part of the potentiation is due to rise in intracellular Ca2+ and stimulation of PKC. Cytochalasin D, which disrupts the actin cytoskeleton, blocked ACPD-elicited chloride currents and ACPD-induced potentiation of NMDAR currents, consistent with a role for cytoskeletal protein(s) in the signaling pathway. As Group I mGluRs are localized to the perisynaptic region in juxtaposition to NMDARs at glutamatergic synapses, mGluR-mediated potentiation of NMDAR activity may play a role in synaptic transmission and plasticity including LTP.

Caspase-activated DNase/DNA fragmentation factor 40 mediates apoptotic DNA fragmentation in transient cerebral ischemia and in neuronal cultures

Nuclear changes, including internucleosomal DNA fragmentation, are characteristic features of neuronal apoptosis resulting from transient cerebral ischemia and related brain insults for which the molecular mechanism has not been elucidated. Recent studies suggest that a caspase-3-mediated mechanism may be involved in the process of nuclear degradation in ischemic neurons. In this study, we cloned from rat brain a homolog cDNA encoding caspase-activated deoxyribonuclease (CAD)/DNA fragmentation factor 40 (DFF40), a 40 kDa nuclear enzyme that is activated by caspase-3 and promotes apoptotic DNA degradation. Subsequently, we investigated the role of CAD/DFF40 in the induction of internucleosomal DNA fragmentation in the hippocampus in a rat model of transient global ischemia and in primary neuronal cultures under ischemia-like conditions. At 8-72 hr after ischemia, CAD/DFF40 mRNA and protein were induced in the degenerating hippocampal CA1 neurons. CAD/DFF40 formed a heterodimeric complex in the nucleus with its natural inhibitor CAD (ICAD) and was activated after ischemia in a delayed manner (>24 hr) by caspase-3, which translocated into the nucleus and cleaved ICAD. Furthermore, an induced CAD/DFF40 activity was detected in nuclear extracts in both in vivo and in vitro models, and the DNA degradation activity of CAD/DFF40 was inhibited by purified ICAD protein. These results strongly suggest that CAD/DFF40 is the endogenous endonuclease that mediates caspase-3-dependent internucleosomal DNA degradation and related nuclear alterations in ischemic neurons.

Antimicrobial peptides: a potential role in ocular therapy

Bacterial pathogens are often involved in contact lens-related adverse responses. This study aimed to find antimicrobial peptides and proteins that effectively eradicate or inhibit ocular bacteria. The antimicrobials were screened against gram-negative and gram-positive bacteria originating from ocular sources. The viability of these ocular bacteria was measured after exposure to the peptides and proteins. Two conditions were used to grow bacteria, low nutrient phosphate-buffered saline and high nutrient tryptone soya broth. Samples were taken at different times up to 48 h. In low nutrient conditions, protamine was found to be the most effective against all strains. Melittin was very effectve against all strains except Serratia and one Pseudomonas isolate which were partially affected. In high nutrient condition, only melittin was effective in killing Staphylococcus aureus. Protamine and the combination of protamine and melittin had the greatest effect in eradicating the bacteria tested in low nutrient condition. Protamine alone and its combination with melittin may have potential therapeutic agents for ocular infections in an era of emerging antibiotic resistance.

Insulin promotes rapid delivery of N-methyl-D- aspartate receptors to the cell surface by exocytosis

Insulin potentiates N-methyl-d-aspartate receptors (NMDARs) in neurons and Xenopus oocytes expressing recombinant NMDARs. The present study shows that insulin induced (i) an increase in channel number times open probability (nP(o)) in outside-out patches excised from Xenopus oocytes, with no change in mean open time, unitary conductance, or reversal potential, indicating an increase in n and/or P(o); (ii) an increase in charge transfer during block of NMDA-elicited currents by the open channel blocker MK-801, indicating increased number of functional NMDARs in the cell membrane with no change in P(o); and (iii) increased NR1 surface expression, as indicated by Western blot analysis of surface proteins. Botulinum neurotoxin A greatly reduced insulin potentiation, indicating that insertion of new receptors occurs via SNARE-dependent exocytosis. Thus, insulin potentiation occurs via delivery of new channels to the plasma membrane. NMDARs assembled from mutant subunits lacking all known sites of tyrosine and serine/threonine phosphorylation in their carboxyl-terminal tails exhibited robust insulin potentiation, suggesting that insulin potentiation does not require direct phosphorylation of NMDAR subunits. Because insulin and insulin receptors are localized to glutamatergic synapses in the hippocampus, insulin-regulated trafficking of NMDARs may play a role in synaptic transmission and plasticity, including long-term potentiation.

[The changes in serum antibody level after immunization with HFRS vaccine]

OBJECTIVES

To observe the changes in serum antibody level after mass immunization with vaccine against hemorrhagic fever with renal syndrome (HFRS) and to evaluate its efficacy and effectiveness in the prevalent areas.

METHODS

Healthy people aged 16 to 60 years in the villages were recruited as study subjects, excluding those suffered from HFRS previously, going out for more than nine months and those with contraindications, and were randomly allocated into immunization and control groups with 10,460 and 16,159 persons, respectively. Specific IgG antibody was determined with indirect immunofluorescent assay (IFA) and neutralizing antibody (NA) was determined with micro CPE method.

RESULTS

Two weeks after the full-course immunization, sero-conversion rate for IFA reached 100% in those sero-negative before immunization, with a 95% confidence interval of 96.3 - 100.0%, and that for NA 44.4%, with a 95% CI of 22.0% - 69.0%. Geometric mean titer (GMT) were 72.1 and 4.6 for IFA and NA, respectively. Booster immunization was provided for them one year later. Positivity of IFA and NA was 28.6%, 83.3%, 75.0%, 53.1%, 22.6% and 14.8%, 55.6%, 35.0%, 31.3%, 26.0%, before booster immunization, two weeks, one year, one and a half years, two years after booster immunization, respectively.

CONCLUSION

HFRS vaccine had good immunogenicity, but its duration of serum antibody sustenance was relatively short.

Induction of oxidative DNA damage in the peri-infarct region after permanent focal cerebral ischemia

To address the role of oxidative DNA damage in focal cerebral ischemia lacking reperfusion, we investigated DNA base and strand damage in a rat model of permanent middle cerebral artery occlusion (MCAO). Contents of 8-hydroxyl-2'-deoxyguanosine (8-OHdG) and apurinic/apyrimidinic abasic sites (AP sites), hallmarks of oxidative DNA damage, were quantitatively measured in nuclear DNA extracts from brains obtained 4-72 h after MCAO. DNA single- and double-strand breaks were detected on coronal brain sections using in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), respectively. Levels of 8-OHdG and AP sites were markedly elevated 16-72 h following MCAO in the frontal cortex, representing the peri-infarct region, but levels did not significantly change within the ischemic core regions of the caudateputamen and parietal cortex. PANT- and TUNEL-positive cells began to be detectable 4-8 h following MCAO in the caudate-putamen and parietal cortex and reached maximal levels at 72 h. PANT- and TUNEL-positive cells were also detected 16-72 h after MCAO in the lateral frontal cortex within the infarct border, where many cells also showed colocalization of DNA single-strand breaks and DNA fragmentation. In contrast, levels of PANT-positive cells alone were transiently increased (16 h after MCAO) in the medial frontal cortex, an area distant from the infarct zone. These data suggest that within peri-infarct brain regions, oxidative injury to nuclear DNA in the form of base and strand damage may be a significant and contributory cause of secondary expansion of brain damage following permanent focal ischemia.

Adaptation of laser-Doppler flowmetry to measure cerebral blood flow in the fetal sheep

The purpose of this study was to devise a means to use laser-Doppler flowmetry to measure cerebral perfusion before birth. The method has not been used previously, largely because of intrauterine movement artifacts. To minimize movement artifacts, a probe holder was molded from epoxy putty to the contour of the fetal skull. A curved 18-gauge needle was embedded in the holder. At surgery, the holder, probe, and skull were fixed together with tissue glue. Residual signals were recorded after fetal death and after maternal death 1 h later. These averaged <5% of baseline flow signals, indicating minimal movement artifact. To test the usefulness of the method, cerebral flow responses were measured during moderate fetal hypoxia induced by giving the ewes approximately 10% oxygen in nitrogen to breathe. As fetal arterial PO(2) decreased from 21.1 +/- 0.5 to 10.7 +/- 0.4 Torr during a 30-min period, cerebral perfusion increased progressively to 56 +/- 8% above baseline. Perfusion then returned to baseline levels during a 30-min recovery period. These responses are quantitatively similar to those spot observations that have been recorded earlier using labeled microspheres. We conclude that cerebral perfusion can be successfully measured by using laser-Doppler flowmetry with the unanesthetized, chronically prepared fetal sheep as an experimental model. With this method, relative changes of perfusion from a small volume of the ovine fetal brain can be measured on a continuous basis, and movement artifacts can be reduced to 5% of measured flow values.

Detection of DNA base-excision repair activity for oxidative lesions in adult rat brain mitochondria

Endogenous oxidative damage to brain mitochondrial DNA and consequential disturbances of gene expression and mitochondrial dysfunction have long been implicated in aging and the pathogenesis of neurodegenerative diseases. It has yet to be determined, however, whether mitochondria in brain cells contain an active DNA repair system and, if so, how this system functions. Therefore, the capacity for the repair of defined types of oxidative DNA lesions has been investigated in adult rat brain mitochondria. Using in vitro DNA incorporation repair assay, we have detected base excision repair (BER) activity for the common oxidative DNA adduct 8-hydroxyl-2'-deoxyguanine (8-oxodG) in mitochondria protein extracts from cortical tissues and cultured primary cortical neurons and astrocytes. The levels of BER activity were both protein concentration-dependent and repair-incubation time-dependent. To resolve the BER pathway, the activity of essential BER enzymes was examined in mitochondria using oligonucleotide incision assay, DNA polymerase assay, and DNA ligase assay employing specific DNA substrates. Mitochondrial extracts were able to remove specifically 8-oxodG, uracil, and the apurinic/apyrimidinic abasic site from substrates. Moreover, a gamma-like DNA polymerase activity and a DNA ligase activity were detected in mitochondiral extracts, based on the formation of specific repair products. These results demonstrate that adult brain mitochondria possess an active BER system for repairing oxidative DNA lesions. This repair system appears to function by sequential actions of DNA repair enzymes that are homologous to, but not identical to, that in the nucleus. Thus, BER may represent an endogenous protective mechanism against oxidative damage to mitochondrial, as well as nuclear, genomes in brain cells.

[The nude mice model of human cryopreserved umbilical cord blood transplantation]

BACKGROUND

To evaluate the hematopoietic potential of long-term cryopreserved human umbilical cord blood as well as the migration of the stem cells in nude mice.

METHODS

Thirty lethally irradiated BALB/ C nu + mice were randomized into 3 groups. One group was injected cryopreserved human umbilical cord blood cells intravenously and one group was injected fresh cord blood and the other one was injected normal saline as control. The survival rates of mice and the successful transplantation evidence were observed and compared among three groups. The migration of the stem cells was analyzed by PCR and fluid cytometry.

RESULTS

The survival rate of the cryopreserved group was much higher than that of the saline group , but there was no significant difference between the fresh group and the cryopreserved group. The evidence of human hematopoiesis was observed by PCR and fluid cytometry and lasted for at least 130 days. In addition , the migration of the cryopreserved stem cells was not the same as that of fresh cord blood , where human gene was hardly detected in liver and kidneys.

CONCLUSIONS

Cryopreservation can keep the hematopoietic potential of cord blood for a long time , but may influence the adhesion molecular of the stem cells , hence influence the homing behavior of the stem cells.

Cerebral oligaemia episode triggers free radical formation and late cognitive deficiencies

Sixty minutes of cerebral oligaemic hypoxia, induced by bilateral clamping of the carotid arteries (BCCA) in pentobarbital-anaesthetized normotensive rats, induces a late progressive cognitive decline when compared with sham-operated controls. Analysis at BCCA of hippocampal metabolism using microdialysis showed increased release of glutamate, aspartate and gamma-aminobutyric acid, followed by a progressive rise in the formation of hydroxyl free radicals measured as 2,3-dihydroxybenzoic acid (2,3-DHBA), their reaction product with salicylate, though only in the re-perfusion phase. In the striatum increased dopamine release occurred during BCCA, whereas glutamate and aspartate showed an increase only during the late re-perfusion phase. gamma-Aminobutyric acid (GABA) concentration increased during BCCA and early re-perfusion. An increase in 2,3-DHBA was seen during BCCA, and persisted over 2 h of re-perfusion. Six and 13 months after surgery, though not as early as 3 months, BCCA-treated rats perform worse than sham-operated controls in a water-maze, where decreased swimming speed reveals striatal dysfunction, while hippocampal dysfunction manifested as diminished spatial bias. These results show that cerebral oligaemia, similarly to cerebral ischaemia, leads to increased extracellular dopamine, aspartate and glutamate, and the production of hydroxyl radicals in structures associated with learning and memory processes. Unlike cerebral ischaemia, in cerebral oligaemia the appearance of spatial memory deficits is delayed.

Formation of the base modification 8-hydroxyl-2'-deoxyguanosine and DNA fragmentation following seizures induced by systemic kainic acid in the rat

The formation of oxidative DNA damage as a consequence of seizures remains little explored. We therefore investigated the regional and temporal profile of 8-hydroxyl-2'-deoxyguanosine (8-OHdG) formation, a hallmark of oxidative DNA damage and DNA fragmentation in rat brain following seizures induced by systemic kainic acid (KA). Formation of 8-OHdG was determined via HPLC with electrochemical detection, and single- and double-stranded DNA breaks were detected using in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl-transferase-mediated nick end-labeling (TUNEL), respectively. Systemic KA (11 mg/kg) significantly increased levels of 8-OHdG within the thalamus after 2 h, within the amygdala/piriform cortex after 4 h, and within the hippocampus after 8 h. Levels remained elevated up to sevenfold within these areas for 72 h. Smaller increases in 8-OHdG levels were also detected within the parietal cortex and striatum. PANT-positive cells were detected within the thalamus, amygdala/piriform cortex, and hippocampus 24-72 h following KA injection. TUNEL-positive cells appeared within the same brain regions and over a similar time course (24-72 h) but were generally lower in number. The present data suggest oxidative damage to DNA may be an early consequence of epileptic seizures and a possible initiation event in the progression of seizure-induced injury to DNA fragmentation and cell death.

[Effect of xinmaitong capsule on total ischemia burden in coronary heart disease patients with myocardial ischemia and analysis of its therapeutical mechanism]

OBJECTIVE

To assess the effect of Xinmaitong (XMT) capsule in treating ischemical cardiac disease.

METHODS

Sixty coronary heart disease (CHD) patients with myocardial ischemia were divided randomly into two groups. XMT group (30 cases) was treated with XMT plus western medicine, and control group (30 cases) with western medicine alone. The changes of the scores for clinical symptoms, the total ischemia burden (TIB), the plasma endothelin (ET), the nitric oxide (NO), the superoxide dismutase (SOD), and the malonyldialdeyde (MDA) levels were observed before and after treatment.

RESULTS

After treatment with XMT the scores of clinical symptoms, TIB, ET and MDA levels were significantly decreased (P < 0.01), the levels of NO and SOD were significantly increased (P < 0.01) in the XMT group, comparing with the control group these changes were statistically different (P < 0.01).

CONCLUSIONS

XMT capsule can act against myocardial ischemia effectively, one of the mechanisms of which is protecting the function of vascular endothelium and resisting lipid peroxidation injury. The effects of adding XMT capsule on conventional treatment of western medicine were better than those of using western medicine alone.

[Resources and utilization of anticarciogenic medical fungi]

This paper summarizes the resources of anticarcinogenic medical fungi, and the information of distribution, eco-environment. It outlines the present statuts of the exploitation and utilization of some species of common anticarcinogenic medical fungi such as Ganoderma lucidum, Coriolus versicolor, Polyporus frondosus etc. The anticarcinogenic mechanism of medical fungi is discussed. Suggestions on how to development and utilize rationally these resources are offered as well.

Characterization and regional distribution of nitric oxide synthase in the human brain during normal ageing

Nitric oxide (NO) is a highly diffusible cellular mediator generated from L-arginine by the enzyme nitric oxide synthase (NOS). As little is known about the regional distribution of NOS in the human brain, we examined the distribution pattern of nitric oxide synthase activity in 28 regions of the human brain using the [(3)H]L-citrulline formation assay. To elucidate which isoforms contribute to the total NOS activity we performed Western blot analysis of neuronal, inducible and endothelial NOS. We further determined brain levels of arginine and citrulline as a potential index of NOS activity pre mortem. NOS activity appears to remain unaltered during ageing and is independent of post mortem delay, gender or sample storage time. We identified a regional pattern of NOS distribution with highest levels of NOS activity in the substantia innominata, cerebellar cortex, nucleus accumbens and subthalamicus, whereas lowest levels were measured in the corpus callosum, thalamus, occipital cortex, and dentate nucleus. nNOS was measured throughout the brain, in contrast iNOS and eNOS were not detectable. We therefore conclude that primarily nNOS is responsible for NOS activity in the human brain. Levels of citrulline were higher than those of arginine, but did not correlate with the enzyme activity, suggesting that these parameters are unsuitable for testing NOS activity premortem. The characterization and topographical pattern of NOS in the human brain during normal ageing may assist our understanding of the physiological role of NO and its relevance in Parkinson's and Alzheimer's disease, alcoholism, schizophrenia and AIDS.

Effect of tear-specific immunoglobulin A on the adhesion of Pseudomonas aeruginosa I to contact lenses

PURPOSE

The aims of the study were (i) to determine the immunodominant antigens of Pseudomonos aeruginoso 1 (Paer1) to tear secretory immunoglobulin A (sIgA); (ii) to study the role of sIgA in inhibiting bacterial adhesion to contact lenses.

METHODS

SDS-PAGE and Western blotting were used to study the interaction of tear sIgA with Paer1; an adhesion assay was used to study the effect of sIgA on the adhesion of Paer1 to the contact lenses.

RESULTS

The results of our study showed that the immunodominant molecules of Paer1 which reacted with tear sIgA were of molecular masses of 105, 50, 45 kDa; the binding of sIgA to Paer1 resulted in a reduction of the adhesion of Paer1 to worn Etafilcon A contact lenses.

CONCLUSIONS

In conclusion, Paer1-specific sIgA are present in tears; the immunodominant molecules of Paer1 may be adhesins and tear-specific sIgA might play an important role in protecting the eye from contact-lens-induced corneal infection by preventing bacterial attachment to contact lenses and the ocular surface.

Involvement of microglia in cerebrospinal fluid glutamate increase in SIV-infected rhesus monkeys (Macaca mulatta)

Cerebrospinal fluid (CSF) samples were collected from 24 uninfected and 24 SIV251 MPBMC-infected rhesus monkeys during early infection and from 6 animals in a longitudinal design up to 7 months postinfection to investigate excitatory and inhibitory amino acid neurotransmitter levels. During the early infection period CSF amino acid concentrations of infected animals were not significantly different from those of uninfected animals. However, long-term studies demonstrated that gamma-aminobutyric acid (GABA) concentrations were decreased while glutamate concentrations were increased late in infection compared with the preinfection values of the same animals. Moreover, we showed that the source of increased glutamate in animals with AIDS is, at least partially, microglial cells. Our data support the hypothesis that excitotoxicity is involved in immunodeficiency virus-induced neurological disease and propose microglia as a contributor to excitotoxic damage.

A preliminary study of steroid reproductive hormones in human hair

Nowadays research and clinical studies of human reproductive endocrinology are generally carried out using human blood reproductive hormone assays. However the acquisition of human blood samples has some shortcomings. In search of new approaches, we paid attention to the fact that progesterone can be detected in cow's hair. Consequently we investigated whether or not steroid hormones are measurable in human hair. The results showed that the levels of steroid hormones in hair are not affected by shampoo and do not significantly vary between different segments of hair (i.e. top, middle and basal segments). The menstrual estradiol and progesterone rhythm of female hair is similar to that of female serum. The ratio of hair estradiol to serum estradiol in the female is 41.2% and that of hair progesterone to serum progesterone is 59.0%; the ratio of hair testosterone to serum testosterone in male is 116%. There are significant correlations between hair and serum steroid hormones of healthy human adult: gamma (estradiol) = 0.395 (n = 20), p < 0.05; gamma (progesterone) = 0.440 (n = 22), p < 0.025 and gamma (testosterone) = 0.395 (n = 25), p < 0.05.

1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline increases extracellular serotonin and stimulates hydroxyl radical production in rats

1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo), a neurotoxin structurally similar to the dopaminergic neurotoxin MPTP, may be formed in humans treated with chloral hydrate or exposed to trichloroethylene, a widely used industrial solvent. Systemically administered TaClo (0.4 mg/kg, i.p.) induced an immediate and transient release of dopamine (DA) and serotonin (5-HT) measured using microdialysis. However, only 5-HT was increased significantly (area under the curve, AUC, for the 1-2 h-period following TaClo administration: 400% compared with the respective control value; 2-3 h-period: 326%). This was followed by a progressive increase in hydroxyl radical formation reflected by higher extracellular concentrations of the hydroxylate product of salicylic acid, 2,3-dihydroxybenzoic acid (AUC for the 1-2 h period following TaClo administration: 182% compared with the respective control value; 2-3 h period: 190%). In contrast, extracellular glutamate and GABA were increased 2-3 h post-injection by 64 and 51%, respectively. These data suggest that TaClo stimulates the generation of hydroxyl free radicals via an acute release of 5-HT and perhaps DA.

Intraoperative microdialysis and tissue-pO2 measurement in human glioma

The amino acid glutamate is one of the major neurotoxins in the pathogenesis of neuronal death after ischemia or trauma. Microdialysis studies in both man and animal have shown elevated extracellular levels after primary lesions. Monitoring of cerebral tissue oxygenation (p(ti)O2) has been used in recent years to detect and prevent episodes of low cerebral oxygenation, e.g. after trauma or subarachnoid hemorrhage. Intraoperative monitoring of p(ti)O2 combined with microdialysis in the peritumoral edema has been chosen to study the responses of glutamate and oxygen levels during resection. In 7/9 patients p(ti)O2 was below "critical" 10 mm Hg. Elevating inspiratory oxygen concentration to 100% led to an increase of p(ti)O2 by 2.5-4 fold and a decrease of glutamate and aspartate by 50-80%. A close correlation between p(ti)O2 and microdialysis glutamate levels was not clearly shown due to frequent intraoperative manipulations.

[Chemical constituents of Phyllanthus urinaria L. and its antiviral activity against hepatitis B virus]

Studies on the chemical constituents of Phyllanthus urinaria and its antiviral activity against hepatitis B virus were completed. Eleven compounds have been isolated. Two of them are new compounds methyl ester dehydrochebulic acid and methyl brevifolin carboxylate. Antiviral experiments on HBsAg in vitro and liver damage caused by CCl4 have shown that. Phyllanthus urinaria possesses antiviral activities against HBV.

Serotyping and genotyping of genital Chlamydia trachomatis isolates reveal variants of serovars Ba, G, and J as confirmed by omp1 nucleotide sequence analysis

Urogenital isolates (n = 93) of Chlamydia trachomatis were differentiated into serovars and variants by serotyping with monoclonal antibodies and genotyping by restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified omp1 gene, respectively. The types of 87 of the 93 isolates (94%) were identical, as determined by both methods. Among these 87 isolates, 3 isolates were identified as the recently described new serovariant Ga/IOL-238 by omp1 nucleotide sequence analysis of the variable domains. Of the remaining six isolates, three isolates serotyped as both L2 and Ba but were identified as Ba/A-7 by genotyping by RFLP analysis of omp1. The omp1 nucleotide sequences of variable domains VD1, VD2, and VD4 of these urogenital Ba strains were identical to the sequences of the variable domains of Ba/J160, an ocular Ba type. The three remaining isolates were serotyped as J, but the patterns obtained by RFLP analysis of omp1, which were identical for the three isolates, differed from that of prototype serovar J/UW36. omp1 nucleotide sequence analysis revealed that these strains are genovariants of serovar J/UW36. Nucleotide sequence differences between serovar J/UW36 and this J genovariant, designated Jv, were found in both variable and constant domains. In conclusion, this study shows that the PCR-based genotyping of clinical C. trachomatis isolates by RFLP analysis of omp1 has a higher discriminatory power and is more convenient than serotyping. Variants of C. trachomatis serovars Ba, G, and J were identified and characterized.