Conversion of gamma-butyrobetaine to L-carnitine by Achromobacter cycloclast

L-Carnitine is an ubiquitous substance that plays a major role in the transportation of long-chain fatty acids. We investigated crucial factors that influence microbial conversion of gamma-butyrobetaine to L-carnitine using an Achromobacter cycloclast strain. Two-stage culture results showed that gamma-butyrobetaine induced enzymes essential for the conversion, which suggests that the precursor should be present in the initial cell growth stage. The addition of yeast extract enhanced L-carnitine production whereas inorganic nitrogen sources inhibited it. Under nitrogen-limiting conditions, the cells accumulated poly-beta-hydroxybutyrate instead of L-carnitine. Among the trace elements tested, nickel addition enhanced L-carnitine production by almost twice that of the control and copper strongly inhibited the conversion. L-Carnitine production was reduced when the medium contained inorganic salts of sodium, potassium, and calcium at a concentration greater than 2 g l(-1). A higher L-carnitine yield was achieved when cells were incubated in a lower culture volume. The optimal pH for L-carnitine production was 5 to 5.5, whereas that of growth was 7.0, indicating that a pH shift was required. Under optimal conditions, L-carnitine concentrations as high as 15 g l(-1) were obtained in 62 h with a 45% molar conversion yield.

Sporosarcina aquimarina sp. nov., a bacterium isolated from seawater in Korea, and transfer of Bacillus globisporus (Larkin and Stokes 1967), Bacillus psychrophilus (Nakamura 1984) and Bacillus pasteurii (Chester 1898) to the genus Sporosarcina as Sporosarcina globispora comb. nov., Sporosarcina psychrophila comb. nov. and Sporosarcina pasteurii comb. nov., and emended description of th

A light-orange-coloured, facultatively anaerobic, rod-shaped bacterium (strain SW28T), which was isolated from seawater in Korea, was taxonomically studied by a polyphasic approach. This organism formed round terminal endospores in swollen sporangia. The peptidoglycan type is A4alpha, based on L-Lys-L-Ala-D-Asp. The predominant menaquinone is MK-7 and the major fatty acid is ante-C15:0. The G+C content of the DNA is 40 mol%. Phylogenetic analysis based on 16S rDNA sequences showed that strain SW28T falls within the radiation of a cluster comprising the rRNA group 2 bacilli and non-Bacillus-type organisms. Strain SW28T showed the highest degree of relatedness to the type strain of Sporosarcina ureae, sharing 96.8% 16S rDNA similarity. Levels of DNA-DNA relatedness between strain SW28T and S. ureae DSM 2281T and the type strains of some Bacillus species forming a coherent phylogenetic cluster are less than 12.5%. On the basis of phenotypic and chemotaxonomic characteristics, 16S rDNA sequence analysis and DNA-DNA relatedness data, it is proposed that strain SW28T should be placed in the genus Sporosarcina as a new species, Sporosarcina aquimarina sp. nov. The type strain is SW28T (= KCCM 41039T = JCM 10887T). From the results of the taxonomic re-evaluation, it is also proposed that Bacillus globisporus, Bacillus psychrophilus and Bacillus pasteurii be transferred to the genus Sporosarcina as Sporosarcina globispora, Sporosarcina psychrophila and Sporosarcina pasteurii, respectively.

The prevalence of chronic prostatitis-like symptoms in young men: a community-based survey

We surveyed the prevalence of chronic prostatitis-like symptoms in young men using the National Institutes of Health (NIH) Chronic Prostatitis Symptom Index (CPSI) and determined the clinical validity of the NIH-CPSI among men in the community. Of 29,017 men aged 20 years dwelling in the community, 8,705 men were randomly selected at a 30.0% sampling fraction and a total of 6,940 men (a response rate 79.7%) completed a self-administered questionnaire. Six percent reported having pain or discomfort in more than one area . About 5% did not feel that the bladder emptied fully after urinating more than 1 time in 5 and 10.5% had to urinate again within 2 h more than 1 time in 5. As the scores for pain or discomfort increased, those for urinary symptoms and impact on quality of life increased (P < 0.001; Armitage test). As the scores for urinary symptoms increased, those for pain or discomfort and impact on quality of life also increased (P < 0.001; Armitage test). The community-based prevalence of chronic prostatitis-like symptoms were found to be high in young men as well as in older men. Our findings indicate that men with pain or urinary symptoms experience a negative impact on their quality of life and the NIH-CPSI provides a valid measure for the general population.

Lateralizing ability of single-voxel proton mr spectroscopy in hippocampal sclerosis: comparison with mr imaging and positron emission tomography

BACKGROUND AND PURPOSE

Proton MR spectroscopy (MRS) is still in the early stages in the evaluation of epilepsy, and comparisons with MR imaging and positron emission tomography (PET) in the same patients have rarely been documented. The purpose of this study was to evaluate the lateralizing ability of single-voxel MRS in comparison with MR imaging and PET in patients with hippocampal sclerosis.

METHODS

Thirty-three patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis and who underwent anterior temporal lobectomy and had good postsurgical outcome over 1-year follow-up were included in the study. MR spectra were obtained from the hippocampus bilaterally, using the point-resolved spectroscopy sequence. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from the relative peak height measurements. An NAA/Cho ratio of 0.8 or less and an NAA/Cr ratio of 1.0 or less were regarded as abnormal. The MRS results were compared retrospectively with those of MR imaging and PET as to the ability to lateralize the epileptogenic focus.

RESULTS

The sensitivity of MRS and PET (concordance with MR imaging) was 85% each in the lateralization of the ipsilateral lesion side. Bilateral abnormalities were seen in 30% of the patients. False-lateralization rates for MRS and PET were 3% and 6%, respectively. The concordance rate of MRS and PET was 73%, when comparing the results of the ipsilateral lesion side.

CONCLUSION

MRS may be used as an adjunct tool in the evaluation of hippocampal sclerosis, like PET, although its sensitivity has to be improved and the clinical significance of bilateral abnormality is still to be determined.

Spinal intradural extramedullary capillary hemangioma: MR imaging findings

SUMMARY

Spinal intradural extramedullary capillary hemangiomas are extremely rare. We present the MR imaging and histologic findings in three patients with this abnormality. The three patients were men who had symptoms of either myelopathy (n = 2) or radiculopathy (n = 1). The tumors were well demarcated, 1.5-2.0 cm in diameter, and were located at the posterior or posterolateral portion of the thecal sac (one at the L1 level and the other two at the midthoracic level). On MR images, the tumor showed isointensity relative to the spinal cord on T1-weighted images, hyperintensity on T2-weighted images, and strong homogeneous enhancement on contrast-enhanced T1-weighted images in all three patients. In two patients, the dural tail sign was observed. Capillary hemangioma should be included in the differential diagnosis of a spinal intradural extramedullary tumor.

Immunohistochemical detection of Prion protein (PrP-Sc) and epidemiological study of BSE in Korea

Though the aetiology of transmissible spongiform encephalopathies (TSEs) remains uncertain, proteinase resistant prion protein (PrP-Sc), a converted form of the normal cellular prion protein (PrP-C), accumulates in the lysosome of cells of the nervous systems of animals with TSEs. In this study, clinical and epidemiological examinations of bovine spongiform encephalopathy (BSE) were conducted in Korea. During the investigated period, none of the cattle exhibited typical clinical signs of BSE, such as behavioral disturbances, high sensitivity, and abnormal locomotion. Immunohistochemical analysis and western immunoblotting were established to detect PrP-Sc in the brain tissue using monoclonal antibody (MAb) F89/160.1.5, produced by immunizing mice with a synthetic peptide which corresponds to bovine PrP residues 146-159, NH2-SRPLIHFGSDYEDRC-COOH. Although some BSE-like spongiform changes were observed in bovine brains randomly collected from Korean slaughterhouses from 1996 to 1999, no PrP-Sc was detected in those brains with the established immunohistochemistry and western immunoblotting assay. Also, no positive reaction was observed in bovine brains infected with rabies. These immunohistochemical and western immunoblotting methods using MAbs, specifically reactive with conserved epitopes on ruminant PrP, can be used for postmortem diagnosis of BSE. Further, the method can be applied to antemortem and the preclinical diagnosis of ovine scrapie by detecting PrP-Sc in lymphoid tissues, such as the tonsils, third eyelid or peripheral lymph nodes.

Immunostimulatory effects of anionic alkali mineral complex solution Barodon in porcine lymphocytes

The anionic alkali mineral complex solution, Barodon (Barodon-S.F. Corp., Korea), was evaluated for its effectiveness as a nonspecific immunostimulator in pigs. The effects of Barodon were determined by analysis of feed efficiency, growth rate, and phenotype of leukocyte subpopulations using monoclonal antibodies specific to porcine leukocyte differentiation antigens and flow cytometry (FC). The study was focused to investigate the change in proportion of the CD4+CD8+ double positive T lymphocyte subpopulation (dpp) which exists uniquely in pigs. In addition, the mitogen-stimulated lymphoproliferative response, tissue distribution in lymphoid organs and the adjuvant effect of Barodon on hog cholera vaccine efficiency were determined. The study has revealed the average daily gain rates and feed conversion rates were significantly (p<0.05) improved in either group of pigs fed with 0.05% Barodon-spray feed (Tx-1) or pigs fed with 3% Barodon-fermented feed (Tx-2) in comparison with group of pigs fed with feed containing no Barodon (control). The proportion of cells expressing CD4+ antigen in Barodon-treated group increased from 3 weeks posttreatment and was significantly higher (p<0.05) than that of control at 8 weeks posttreatment. Particularly, the significantly higher proportion was maintained from 8 weeks through 13 weeks posttreatment in Tx-1 group (p<0.05). The proportion of cells expressing CD8+ antigen was significantly higher at 3 weeks posttreatment in Tx-2 (p<0.01). Proportion of MHC class II-expressing cells was significantly higher in Tx-1 and Tx-2 group at 11 weeks and 8 weeks posttreatment (p<0.05), respectively. In addition, the proportion of Non T/Non B (N) cells was also significantly higher in Tx-2 at 3 weeks posttreatment (p<0.01) and maintained to 13 weeks posttreatment (p<0.1). Between Barodon-treated groups, the proportion of MHC class II-expressing cells was observed to be larger in Tx-2 than Tx-1 from 3 weeks to 8 weeks posttreatment (p<0.05). However, there were no significant difference in the proportions of CD2+ cells, B cells, monocytes and granulocytes between Barodon-treated and control group during the experiment. Dual-color FC analysis, study has revealed an increased proportion of dpp present in lymphocytes obtained from peripheral blood (PB) and mesenteric lymph node (MLN) of Barodon-treated group at 8 and 11 weeks posttreatment. The proportion of dpp in PB was 27.5% and 32.1% in Tx-1 and Tx-2, respectively, but only 2.2% in control group at 8 weeks posttreatment. In MLN, the proportion was 45.1% and 52.1% in Tx-1 and Tx-2, respectively, otherwise 16.5% in control group at 8 weeks posttreatment. The mitogen-stimulated activity was significantly higher in Tx-1 than in the control group at 11 weeks posttreatment when cells were stimulated with Con A and PHA, respectively (p<0.01). Also, Con A-, PHA and PWM-stimulated activity was significantly higher in Tx-2 than in the control group at the same time (p<0.05). The tissue distribution of CD4+, CD8+ and CD4+CD8+ dpp in MLN and spleen was significantly larger in Tx-1 and Tx-2 than in the control group (p<0.01). Also, a larger proportion of dpp was observed in Tx-2 than Tx-1 in spleen between Barodon-treated groups (p<0.01). In conclusion, the study has demonstrated that Barodon had an immunostimulatory effect on pigs through proliferation and activation of porcine immune cells, specially CD4+CD8+ dpp lymphocytes.

Synthesis and antiviral activity of D- and L-2'-azido-2',3'-dideoxy-4'-thiopyrimidine and purine nucleosides

Novel D- and L-2'-azido-2',3'-dideoxy-4'-thionucleosides were synthesized starting from L- and D-xylose via D- and L-4-thioarabitol derivative as key intermediates and evaluated for antiviral activity, respectively. When the final nucleosides were tested against HIV-1, HSV-1, HSV-2, and HCMV, they were found to be only active against HCMV without cytotoxicity up to 100 micrograms/ml.

A unique pattern of mycelial elongation of Blakeslea trispora and its effect on morphological characteristics and beta-carotene synthesis

The mycelial morphology of Blakeslea trispora was of crucial importance in the production of beta-carotene in submerged cultures of B. trispora. After the spores were inoculated, the time-course variation of mycelial morphology was closely examined under the microscope. With the addition of the non-ionic surfactant (Span 20: Sorbitan monolaurate, E493) to the culture medium, a unique pattern of mycelial elongation was observed: 1) slow formation of germ tubes from spores and 2) appearance of mycelia with very short length, which allowed a well-dispersed growth of B. trispora without significant pellet aggregation. Span 20 appears to act like a paramorphogen. Without Span 20, however, the fungal culture finally formed a big clump of mycelium owing to heavy cross-linking of long mycelia. But the short mycelium maintained in the course of cultivation seemed to be irrelevant to growth inhibition, because the final concentration of dry mycelium was much higher with Span 20 after 3-day cultivation. The 20-fold increase in specific yield of beta-carotene (mg beta-carotene produced per g mycelium) was achieved with this drastic change in the pattern of mycelial elongation. The reason for this result might be more effective mass transfer and/or enhanced sensitivity to environmental oxidative stress in the well-dispersed mycelial cultures of B. trispora.

Infected hydrocele in a neonate

A case of infected hydrocele in a neonate is presented. We describe this unusual condition, and discuss the diagnosis, pathophysiology and treatment.

Secretory production of Arthrobacter levan fructotransferase from recombinant Escherichia coli

Levan fructotransferase (LFTase) from Arthrobacter ureafaciens K2032 was expressed with N-terminal fusion of a LacZ-derived secretion motif (TMITNSSSVP) using the lac promoter system in recombinant Escherichia coli JM109 [pUDF-A81]. In flask cultures, recombinant enzyme activity was detected in culture media, and sequence analysis of N-terminal residues showed that about 40% of the extracellular recombinant LFTase had an authentic N-terminus. In a fed-batch bioreactor containing recombinant E. coli at high cell concentrations (OD(600)>200), the extracellular LFTase accumulated to 46000 U ml(-1) (approximately 2.0 g l(-1)) which was almost 40% of total (intra- and extracellular) recombinant LFTase. The synthesized recombinant enzyme was secreted soon after gene expression was induced by IPTG. Prolonged high secretion caused cell lysis and growth inhibition during the production phase in fed-batch cultures. When lactose was added by continuous feed mode, the secretion of recombinant LFTase and hence the cell lysis were significantly delayed in spite of the increased synthesis level. Therefore the induced cell culture of recombinant E. coli could grow up to a much higher cell concentration with continuing recombinant enzyme synthesis. In the case of the controlled feed of lactose, the maximum activities (U ml(-1)) of total and extracellular LFTase were nearly 100% and 70% higher, respectively.

Enhancement of glucose oxidase production in batch cultivation of recombinant Saccharomyces cerevisiae: optimization of oxygen transfer condition

AIMS

To obtain an optimal combination of agitation speed and aeration rate for maximization of specific glucose oxidase (GOD) production in recombinant Saccharomyces cerevisiae, and to establish a correlation between kLa vis-à-vis oxygen transfer condition and specific glucose oxidase production.

METHODS AND RESULTS

The oxygen transfer condition was manifested indirectly by manipulating the impeller speed and aeration rate in accordance with a Central Composite Rotatory Design (CCRD). The dissolved oxygen concentration and the volumetric oxygen transfer coefficient (kLa) were determined at corresponding combinations of impeller speed and aeration rate. The maximal specific extracellular glucose oxidase production (3.17 U mg-1 dry cell mass) was achieved when the initial dissolved oxygen concentration was 6.83 mg l-1 at the impeller speed of 420 rev min-1 and at the rate of aeration of 0.25 vvm. It was found out that while impeller speed had a direct effect on the production of enzyme, a correlation between kLa and specific GOD production could not be established.

CONCLUSION

At the agitation speed of 420 rev min-1 and at 0.25 vvm aeration rate, the degree of turbulence and the dissolved oxygen concentration were thought to be optimal both for cellular growth and production of enzyme.

SIGNIFICANCE AND IMPACT OF THE STUDY

The combined effect of agitation and aeration on recombinant glucose oxidase production in batch cultivation has not yet been reported in the literature. Therefore, this study gives an insight into the effect of these two important physical parameters on recombinant protein production. It also suggests that since there is no correlation between kLa and specific production of GOD, kLa should not be used as one of the scale-up parameters.

External compression of bronchus by aneurysm from divided major aortopulmonary collateral artery after unifocalization

The right ventricle to pulmonary artery connection with an extracardiac conduit, left pulmonary artery reconstruction, ligation of patent ductus arteriosus, and take-down of right Blalock--Taussig shunt were performed on a 1-year-8-month-old boy who had pulmonary atresia, ventricular septal defect, patent ductus arteriosus, and major aortopulmonary collateral arteries. He previously underwent the unifocalization and right modified Blalock--Taussig shunt at 9 months of age. He repeatedly had a difficulty in weaning from the mechanical ventilator. After removing the aneurysm from the divided major aortopulmonary collateral artery that compressed the left main bronchus externally, it was possible to wean him from the mechanical ventilator.

Practical guidelines for the preservation of the pancreaticoduodenal arteries during duodenum-preserving resection of the head of the pancreas: clinical experience and a study using resected specimens from pancreaticoduodenectomy

BACKGROUND/AIMS

The purpose of this study was to create a practical guideline for vascular preservation during duodenum-preserving resection of the head of the pancreas.

METHODOLOGY

We examined the anatomy of pancreaticoduodenal arteries by specimen angiography and dissection using 12 pancreaticoduodenectomy specimens. We also reviewed our experiences with duodenum-preserving resection of the head of the pancreas.

RESULTS

In the specimens, the posterior pancreaticoduodenal artery and its duodenal branches were easily separated from the posterior surface of the pancreas, and its papillary branch was identified in two-thirds of the cases. It was difficult to dissect the anterior superior pancreaticoduodenal arteries from the pancreas because they were partially buried in the pancreatic parenchyma. The anterior inferior pancreaticoduodenal artery located in the posterior and inferior surface of the pancreas could be safely dissected in two-thirds of the cases. Duodenum-preserving resection of the head of the pancreas was performed in 7 patients. In every case, the anterior superior pancreaticoduodenal artery was sacrificed and the anterior inferior pancreaticoduodenal artery was preserved. In 3 cases, the entire posterior pancreaticoduodenal artery was preserved and in 4 cases a short segment of the posterior pancreaticoduodenal artery was removed accidentally. The pancreatic head was totally removed and the intrapancreatic common bile duct was preserved. There were 3 postoperative complications, pancreatic leakage, intraabdominal fluid collection and bile duct stricture. They improved with conservative management.

CONCLUSIONS

To safely perform duodenum-preserving resection of the head of the pancreas, preservation of the whole posterior pancreaticoduodenal artery and anterior inferior pancreaticoduodenal artery is recommended because they can be safely dissected from the pancreas, and the posterior pancreaticoduodenal artery provides the major blood supply to the papilla and distal bile duct. However, removal of a short segment of posterior pancreaticoduodenal artery does not preclude a good blood supply to the duodenum because of bidirectional blood flow.

N-(3-Acyloxy-2-benzylpropyl)-N'-(4-hydroxy-3-methoxybenzyl) thiourea derivatives as potent vanilloid receptor agonists and analgesics

A series of N-(3-acyloxy-2-benzylpropyl)-N'-(4-hydroxy-3-methoxybenzyl) thiourea derivatives were investigated as vanilloid receptor ligands in an effort to discover a novel class of analgesics. The proposed pharmacophore model of resiniferatoxin. which includes the C20 homovanillic moiety, the C3-carbonyl and the orthoester phenyl ring as key pharmacophoric groups, was utilized as a guide for drug design. The compounds were synthesized after several steps from diethylmalonate and evaluated in vitro in a receptor binding assay and in a capsaicin-activated channel assay. Additional evaluation of analgesic activity, anti-inflammatory activity and pungency was conducted in animal models by the writhing test, the ear edema assay, and the eye-wiping test, respectively. Among the new compounds, 23 and 28 were found to be the most potent receptor agonists of the series with Ki values of 19 nM and 11 nM, respectively. Their strong in vitro potencies were also reflected by an excellent analgesic profile in animal tests with ED50 values of 0.5 microg kg for 23 and 1.0 microg/kg for 28. Relative to capsaicin these compounds appear to be ca. 600 and 300 times more potent. Both 23 and 28 were found to be less pungent than capsaicin based on the eye-wiping test. However, the compounds did not show significant anti-inflammatory activity. A molecular modeling study comparing the energy-minimized structures of resiniferatoxin and 35 demonstrated a good correlation in the spatial disposition of the corresponding key pharmacophores. The thioureas described in this investigation, which were designed as simplified resiniferatoxin surrogates, represent a novel class of potent vanilloid receptor agonists endowed with potent analgesic activity and reduced pungency.

Staphylococcus aureus agr genotypes with enterotoxin production capabilities can resist neutrophil bactericidal activity

Staphylococcus aureus pathogenicity is mainly due to the production of a number of secreted and cell surface-associated proteins under the regulation of the agr gene. A region of the agr gene was used to subgroup S. aureus strains according to restriction fragment length polymorphisms. Additionally, strains were subtyped according to the coagulase gene in order to strengthen discriminatory power. Virulence capabilities of agr genotype subgroups were evaluated using an in vitro neutrophil bactericidal assay, which showed that prevalent genotypes were significantly better at evading this primary host defense. Multiplex PCR was then used to detect enterotoxin genes among the genotype subgroups in order to determine possible virulence candidates that enable strains to combat neutrophil killing. The prevalent genotype strains were found to possess higher production capabilities for enterotoxin A than did low-prevalence strains. The significance of enterotoxin A production capabilities in affecting pathogenicity of S. aureus strains was evaluated and found to have a profound effect on neutrophil killing abilities. The use of a large epidemiological database as a tool for subgrouping strains with varying degrees of pathogenicity has allowed the identification of relevant and previously undefined virulence factors that affect a pathogen's capability to overcome host immune defenses.

N-butyl-2-cyanoacrylate pulmonary embolism after endoscopic injection sclerotherapy for gastric variceal bleeding

PURPOSE

The purpose of this work was to describe the radiologic and clinical manifestations of n-butyl-2-cyanoacrylate pulmonary embolism (PE) after endoscopic injection sclerotherapy (EIS) for gastric variceal bleeding.

METHOD

From 1992 to 1999, the medical records of 140 patients who had undergone EIS using n-butyl-2-cyanoacrylate were reviewed for identification of respiratory symptoms and amount of injection, and their pre- and postprocedure chest radiographs were reviewed to identify PE. In patients with PE, pre- and postprocedure chest radiographs (6/6), chest CT scans (3/6), lung perfusion scans (3/6), and follow-up chest radiographs (6/6) were analyzed retrospectively.

RESULTS

Radiographically evident PE was observed in 6 (4.3%) of 140 patients. In comparison with patients without emboli, these patients received a higher mean volume of injection (4.2 vs. 1.8 ml) (p = 0.0011). Four of the six patients with pulmonary emboli had respiratory symptoms. Chest radiographs and CT scans showed unusual tubular or nodular, radiopaque pulmonary emboli along the pulmonary vessels. Multiple peripheral, wedge-shaped, subsegmental perfusion defects were seen on perfusion lung scans. In five of six patients, the radiographic abnormalities showed complete or partial resolution. There were no fatalities directly associated with PE.

CONCLUSION

Radiographically evident PEs are uncommonly observed following EIS and appear to be more common in patients receiving a higher volume of liquid acrylate. Affected patients were either mildly symptomatic or asymptomatic, and there were no direct fatalities of this complication.

The excisional, plication and internal drainage techniques: a comparison of the results for idiopathic hydrocele

OBJECTIVE

To assess the results of the excision, plication and internal drainage techniques for hydrocele repair.

PATIENTS AND METHODS

Between January 1990 and June 1998, 132 patients (mean age 54.36 years, range 16-83) underwent repair for idiopathic hydrocele using one of three techniques (excision, eversion/plication or internal drainage); the complication and recurrence rates of each technique were evaluated.

RESULTS

The excisional technique resulted in the highest complication rate (81%) and the internal drainage technique the lowest (7%). Postoperative scrotal oedema occurred in 74% of patients after plication and this was the highest rate among the techniques (P < 0.001). Differences in the rates of wound infection and haematoma among the three techniques were not statistically significant. The internal drainage technique had the highest recurrence rate (85%) and the excisional technique the lowest (1.3%; P < 0.001).

CONCLUSIONS

Although useful, the internal drainage technique has a high recurrence rate and we suggest abandoning its use for hydrocele repair. The present results suggest that plication is better than excision, causing fewer complications, and better than internal drainage, as the results are more favourable.

A genetic map of cucumber composed of RAPDs, RFLPs, AFLPs, and loci conditioning resistance to papaya ringspot and zucchini yellow mosaic viruses

The watermelon strain of papaya ringspot virus (PRSV-W) and zucchini yellow mosaic virus (ZYMV) are potyviruses that cause significant disease losses in cucumber. Resistances have been identified primarily in exotic germplasm that require transfer to elite cultivated backgrounds. To select more efficiently for virus resistances, we identified molecular markers tightly linked to PRSV-W and ZYMV resistances in cucumber. We generated F6 recombinant inbred lines (RILs) from a cross between Cucumis sativus L. 'Straight 8' and a line from 'Taichung Mou Gua', TMG1 (susceptible and resistant, respectively, to both viruses), and studied the segregations of amplified fragment length polymorphism (AFLP) markers, randomly amplified polymorphic DNAs (RAPDs), restriction fragment length polymorphisms (RFLPs), and resistances to PRSV-W and ZYMV. A 353-point map of cucumber was generated, delineating 12 linkage groups at LOD 3.5. Linkage arrangements among RFLPs were consistent with previously published maps; however linkages among RAPDs in our map did not agree with a previously published map. Resistances to PRSV-W and ZYMV were tightly linked (2.2 cM) and mapped to the end of one linkage group. One AFLP cosegregated with resistance to ZYMV.

K-ras oncogene mutation in cancer and precancerous lesions of the gallbladder

BACKGROUND AND OBJECTIVES

To determine whether K-ras mutation plays any role in the development and progression of gallbladder cancer, or has any clinical or pathological significance in gallbladder cancer patients, we investigated the presence and incidence of this mutation in the normal mucosa, and precancerous and cancerous lesions of the gallbladder.

METHODS

DNA was obtained from normal mucosa, dysplastic mucosa, primary cancer tissues, and metastatic lymph nodes that were identified and microdissected from the paraffin blocks of 20 gallbladder cancer cases. K-ras codon 12 mutations were investigated using a modified two-step polymerase chain reaction and the restriction fragment length polymorphism method, and by direct sequencing with an automated sequencer.

RESULTS

K-ras mutations were detected in the tissues of 10 out of the 20 patients. A mutation was present in the dysplastic epithelium associated with the primary carcinoma in 3 out of 12 specimens, in metastatic carcinoma in 1 out of 5 patients, and in primary carcinoma in 8 out of 20 patients. Mutation was found only once in the dysplastic, noncancerous epithelium, and only once in a metastatic tumor although not detectable in the primary cancer. Direct sequencing showed that the mutations were G to C substitutions (GGT-->CGT) at the first site of codon 12, except in two cases (GGT-->TGT). There were no correlations between K-ras mutations and clinicopathological factors.

CONCLUSIONS

K-ras mutations were detected in half of the gallbladder cancer cases. We suggest that K-ras mutation may play a role in the development of premalignant lesions or early carcinogenesis in some gallbladder cancers. We were unable to find any evidence that K-ras mutation plays any role in tumor progression or metastasis, or that it has any clinicopathological significance.

Rhodococcus pyridinivorans sp. nov., a pyridine-degrading bacterium

The taxonomic position of a bacterial strain (PDB9T) that is capable of degrading pyridine was clarified by a polyphasic taxonomic approach using phenotypic, chemotaxonomic and genetic methods. The cells, which are rods and branched filaments during the early growth phase, fragment into short rods or cocci, thereby completing the growth cycle. Strain PDB9T was found to have a cell wall of chemotype IV, MK-8(H2) as the predominant menaquinone, mycolic acids with 36-46 carbon atoms and C16:0' C18:1 cis9, 10-methyl-C18:0 (TBSA) as the major fatty acids. The G+C content of the DNA was 66 mol%. The phylogenetic tree showed that strain PDB9T falls within an evolutionary radiation comprising Rhodococcus species and is most closely related to the type strain of Rhodococcus rhodochrous, sharing 99% 16S rDNA similarity. The differences in some phenotypic characteristics and the genetic distinctiveness distinguish strain PDB9T from the Rhodococcus species described previously. Therefore, strain PDB9T should be placed in the genus Rhodococcus as a new species, for which the new name Rhodococcus pyridinivorans sp. nov. is proposed. The type strain of the new species is strain PDB9T (= KCTC 0647BPT = KCCM 80005T).

Comparative sequence analyses of the ribonuclease P (RNase P) RNA genes from LL-2,6-diaminopimelic acid-containing actinomycetes

Ribonuclease P (RNase P) RNA genes of LL-2,6-diaminopimelic acid (LL-A2pm)-containing actinomycetes, except Streptomyces species, were sequenced after PCR-amplification and cloning. By using the sequence data, the relationships between species within genera and the relationships between taxa above genus level were investigated and the usefulness of the RNase P RNA gene as another phylogenetic marker was evaluated. RNase P RNA gene sequences of all strains used in this study contained relatively conserved regions along with highly variable regions. The mean RNase P RNA gene similarity value was approximately 82 +/- 18% and the mean RNase P RNA gene similarity value when gaps were included was approximately 76 +/- 24%. The nucleotide similarities between the RNase P RNA genes of different strains were mostly fewer than the 16S rDNA similarities. The RNase P RNA gene was more useful than 16S rDNA for clearly differentiating the relationships between species belonging to a genus and the relationships between some genera. However, nucleotide sequences of RNase P RNA genes were not necessarily appropriate for comparisons at all taxonomic levels (such as those between species, between genera and between families).