Ginsenoside-Rp1 inhibits platelet activation and thrombus formation via impaired glycoprotein VI signalling pathway, tyrosine phosphorylation and MAPK activation

BACKGROUND AND PURPOSE

Ginsenosides are the main constituents for the pharmacological effects of Panax ginseng. Such effects of ginsenosides including cardioprotective and anti-platelet activities have shown stability and bioavailability limitations. However, information on the anti-platelet activity of ginsenoside-Rp1 (G-Rp1), a stable derivative of ginsenoside-Rg3, is scarce. We examined the ability of G-Rp1 to modulate agonist-induced platelet activation.

EXPERIMENTAL APPROACH

G-Rp1 in vitro and ex vivo effects on agonist-induced platelet-aggregation, granule-secretion, [Ca(2+) ](i) mobilization, integrin-α(IIb) β(3) activation were examined. Vasodilator-stimulated phosphoprotein (VASP) and MAPK expressions and levels of tyrosine phosphorylation of the glycoprotein VI (GPVI) signalling pathway components were also studied. G-Rp1 effects on arteriovenous shunt thrombus formation in rats or tail bleeding time and ex vivo coagulation time in mice were determined. KEY RESULT: G-Rp1 markedly inhibited platelet aggregation induced by collagen, thrombin or ADP. While G-Rp1 elevated cAMP levels, it dose-dependently suppressed collagen-induced ATP-release, thromboxane secretion, p-selectin expression, [Ca(2+) ](i) mobilization and α(IIb) β(3) activation and attenuated p38(MAPK) and ERK2 activation. Furthermore, G-Rp1 inhibited tyrosine phosphorylation of multiple components (Fyn, Lyn, Syk, LAT, PI3K and PLCγ2) of the GPVI signalling pathway. G-Rp1 inhibited in vivo thrombus formation and ex vivo platelet aggregation and ATP secretion without affecting tail bleeding time and coagulation time, respectively.

CONCLUSION AND IMPLICATIONS

G-Rp1 inhibits collagen-induced platelet activation and thrombus formation through modulation of early GPVI signalling events, and this effect involves VASP stimulation, and ERK2 and p38(-MAPK) inhibition. These data suggest that G-Rp1 may have therapeutic potential for the treatment of cardiovascular diseases involving aberrant platelet activation.

Degradation and toxicity assessment of sulfamethoxazole and chlortetracycline using electron beam, ozone and UV

Recently, the occurrence of antibiotics in sewage treatment plant effluent, as well as drinking water, has raised concern about their potential impacts on the environment and public health. Antibiotics are found in surface and ground waters, which indicate their ineffective removal by conventional wastewater treatment processes. Therefore, advanced oxidation processes (AOPs) have received considerable attention for the removal of antibiotics. This study was conducted to evaluate the degradation and mineralization of antibiotics (sulfamethoxazole and chlortetracycline) using an electron beam, ozone and UV, and the change of toxicity. Also, the electrical energy consumption based on the EE/O parameter (the electrical energy required per order of pollutants removal in 1 m(3) wastewater) was used to quantify the energy cost associated with the different AOPs (electron beam, ozone and UV) for the degradation of antibiotics. The results showed that an electron beam effective for the removals of both sulfamethoxazole and chlortetracycline in aqueous solutions. However, degradation of the target compounds by ozone and UV showed different trends. The oxidation efficiency of each organic compound was very dependent upon the AOP used. Algal toxicity was significantly reduced after each treatment. However, based on the electrical energy, the electron beam was more efficient than ozone and UV. Electron beam treatment could be an effective and safe method for the removal of antibiotic compounds.

Biochemical effects of veterinary antibiotics on proliferation and cell cycle arrest of human HEK293 cells

The purpose of this study was to examine the effects of veterinary antibiotics, including amoxicillin (AMX), chlortetracycline (CTC) and tylosin (TYL), on the biochemical mechanism of human embryonic kidney cells (HEK293). CTC and TYL inhibited HEK293 cell proliferation, in both time- and dose-dependent manners, and changed the cell morphology; whereas, AMX showed no cytotoxic effects. The cell cycle analysis of CTC and TYL revealed G1-arrest in HEK293 cells. Western blot analysis also showed that CTC and TYL affected the activation of DNA damage responsive proteins, as well as cell cycle regulatory proteins, such as p53, p21(Waf1/Cip1) and Rb protein, which are crucial in the G1-S transition. The activation of p21(Waf1/Cip1) was significantly up-regulated over time, but there was no change in the level of CDK2 expression. The results of this study suggest that veterinary antibiotics, even at low level concentrations on continuous exposure, can potentially risk the development of human cells.

Embryonic toxicity changes of organic nanomaterials in the presence of natural organic matter

When elucidating the potential fate and bioavailability of nanomaterials (NMs) in an aquatic system, it is important to consider the interactions between NMs and natural organic matter (NOM). The present study compared the toxicities of carbon-based NMs, with disparate physicochemical properties, on Japanese medaka (Oryzias latipes) embryos after the addition of NOM. The measured embryonic toxicity parameters were mortality, malformation and hatching delay. Various physicochemical properties of water suspended fullerenes (nC(60)) and multi-walled carbon nanotubes (MWNTs) were modulated by organic exchange (Tol/nC(60)), stirring over time (Aqu/nC(60)) and acid treatment (f-MWNTs) followed by characterization. Tol/nC(60) produced relatively more hydrophobic surfaces and exhibited smaller closed spherical agglomerates than Aqu/nC(60). Acid-treated f-MWNTs displayed functionalized hydrophilic surfaces compared to raw MWNTs (r-MWNTs). The resultant embryonic toxicities, in the absence of NOM, were ranked in the order: f-MWNTs>Tol/nC(60)>Aqu/nC(60). As the NOM concentrations were increased, no changes in embryonic toxicities were observed on exposure of Aqu/nC(60) and r-MWNTs; whereas, the toxicities were reduced on exposure to Tol/nC(60) and f-MWNTs, due to a disappearance of hydrophobic primary spherical aggregates and partial coating, respectively. These data suggest that in the presence of NOM, the morphological differences of NMs, as well as their physicochemical properties, play a significant role in their reactions and subsequent medaka embryonic nanotoxicity.

Does donor kidney to recipient body weight ratio influence long-term outcomes of living-donor kidney transplantation?

This study evaluated the effect of the donor kidney to recipient body weight (Kw/Rw) ratio on long-term graft function and survival. We investigated retrospectively whether there was any association between Kw/Rw ratio and long-term graft survival and function after a follow-up of >10 years. We studied a consecutive series of 123 adult-to-adult living kidney transplants. According to the Kw/Rw ratio, patients were divided into 3 groups: "low" (Kw/Rw <2.85; n = 29), "medium" (2.85 ≤ Kw/Rw < 4.04; n = 63), and "high" (≥4.04; n = 31). Among the 3 groups, the mean serum creatinine levels at 1 and 6 months as well as 1 year after transplantation were significantly lower among patients with a high Kw/Rw ratio than in those with a medium or low ratio, but serum creatinine levels at 3 and 5 years did not differ significantly (P = .394 and 0.620, respectively). Graft survival rates at 5 and 10 years after transplantation were significantly lower in the "low" group. We observed a significant association between Kw/Rw ratio and graft survival (P = .018). The Kw/Rw ratio is an important factor for long-term graft survival and early graft function. However, it did not significantly affect subsequent renal function.

The individual and population effects of tetracycline on Daphnia magna in multigenerational exposure

Multigenerational exposure of Daphnia magna to tetracycline was carried out through four consecutive generations. The effects of tetracycline on the survival, reproduction and growth of D. magna were assessed over a period of 21 days per generation. The evaluated endpoints were overall fecundity (total mean neonates per female over 21 days), time to first reproduction, longevity, molting number and somatic growth, such as body weight and body length. Using the results obtained for reproduction and survival rates, the intrinsic population growth rate (PGR) was calculated and compared throughout the generations. Reproductive impairment was observed in all generations and magnified with increasing generation number. The value of no observed effect concentration on D. magna also markedly decreased with increasing generation number. This subsequently resulted in a reduction of the PGR value. In addition, the PGR value was decreased with increasing exposure concentration, decreasing by about 30 and 60% at 0.1 and 5.0 mg/L tetracycline, respectively. On the other hands, somatic growth increased with increasing generation number, because the remaining input energy from the reduced reproduction was mainly used for body maintenance. As a result, the somatic growth and reproduction showed reversed trends on continuous exposure of tetracycline to four generations. In conclusion, multigenerational exposure of tetracycline can induce overall responses on reproduction and the somatic growth of D. magna. Moreover, the PGR value of D. magna exposed to tetracycline was reduced with increasing generation number; thereby, inhibiting the long term propagation of D. magna.

Pesticide poisonings in South Korea: findings from the National Hospital Discharge Survey 2004-2006

OBJECTIVES

Pesticide poisoning stands as a major public health issue worldwide. The objective of this study was to examine the epidemiologic characteristics of pesticide-related hospitalizations in South Korea.

METHODS

Data from the Korea National Hospital Discharge Survey were analyzed to describe the epidemiologic characteristics of pesticide poisoning among hospitalized patients from 2004 through 2006. Pesticide-related hospitalizations were identified using the International Classification of Diseases, Tenth Revision codes. National estimates of pesticide-related hospitalizations were calculated using sampling weights for number of hospitalizations.

RESULTS

A total of 25,982 pesticide-related hospitalizations were estimated during the years 2004-2006, yielding an average annual pesticide-related hospitalization rate of 17.8 per 100,000 population in South Korea. Age-specific rates for pesticide-related hospitalization increased with age, with the highest rate noted among those aged 70 or above. The majority of pesticide-related hospitalization was cases of intentional poisoning in rural areas. Seasonal variation in the rate was observed, with summer being the highest among both men and women.

CONCLUSIONS

Pesticide-related hospitalization is prevalent and demonstrates demographic and seasonal and regional variations. More effective strategies to reduce pesticide-related hospitalizations are required in South Korea.

Oocyte maturity in repeated ovarian stimulation

Objective

During stimulated IVF cycles, up to 15% of oocytes are recovered as immature. The purpose of this study was to investigate the trend of oocyte maturity in repeated ovarian stimulation for IVF.

Methods

One hundred forty-eight patients were selected who underwent two consecutive IVF cycles using same stimulation protocol during 2008 to 2010. Ovarian stimulation was performed with FSH and human menopausal gonadotropin and flexible GnRH antagonist protocol in both cycles. Oocyte maturity was assessed according to presence of germinal vesicle (GV) and the first polar body. Immature oocyte was defined as GV stage or metaphase I oocyte (GV breakdown with no visible polar body) and cultured up to 48 hours. If matured, they were fertilized with ICSI.

Results

Percentages of immature oocytes were 30.8% and 32.9% (p=0.466) and IVM rates of immature oocytes were 36.2% and 25.7% (p=0.077), respectively. A significant correlation was noted between percentage of immature oocytes in the two cycles (R=0.178, p=0.03). Women with >40% immaturity in both cycles (n=21) showed lower fertilization rate of in vivo matured oocytes (56.4% vs. 72.0%, p=0.005) and lower pregnancy rate (19.0% vs. 27.1%, p=0.454) after the second cycle when compared with women with <40% immaturity (n=70). In both groups, female age, number of total retrieved oocyte and embryos transferred were similar.

Conclusion

In repeated ovarian stimulation cycles for IVF, the immature oocyte tended to be retrieved repetitively in consecutive IVF cycles.

Effects of biodegradation and sorption by humic acid on the estrogenicity of 17β-estradiol

The removal of 17β-estradiol (E2) by biodegradation and sorption onto humic acid (HA) was examined at various HA concentrations. Subsequently, estrogenicity associated with E2 removal was estimated using E-screen bioassay. Results showed that E2 biodegradation and its subsequent transformation to estrone (E1) were significantly reduced with increasing HA concentration. In addition, the presence of nutrients enhanced the biodegradation of E2. Overall, E2 biodegradation was the dominating contributor to its removal, which demonstrated a significantly negative correlation with E2 sorption at various HA concentrations. The sorption of E2 by HA was significantly enhanced with increasing HA concentration. Estrogenicity associated with residual E2 showed that there existed a significant difference among various HA concentrations, with the lowest value in the absence of HA. The findings suggest that the presence of HA and nutrients in natural waters should be considered in assessing estrogenicity of environmental samples due to complex sorption and biodegradation processes.

Avoiding abdominal flank bulge after anterolateral approaches to the thoracolumbar spine: cadaveric study and electrophysiological investigation

Object

The thoracolumbar junction is frequently accessed through an anterolateral approach with the incision and muscle dissection extending from the lower thoracic region to the lateral border of the rectus abdominis muscle. This approach is frequently associated with the subsequent development of an unsightly and uncomfortable relaxation of the ipsilateral abdominal wall, or flank bulge, caused by denervation injury to the intercostal nerves. However, the etiology of this complication is not widely recognized by spine surgeons. The object of this study was to better define the relevant anatomy and innervation of the anterolateral abdominal wall musculature.

Methods

The authors performed 32 cadaveric dissections and 6 intraoperative electromyography (EMG) evaluations.

Results

The cadaveric dissection studies and intraoperative EMG evaluations provided detailed anatomy of the anterolateral abdominal wall and its innervation. Cadaveric dissections revealed that the most significant intercostal nerve contributions to the anterolateral abdominal wall arise from T11 and T12. Electrophysiological confirmation of these findings was accomplished through intraoperative stimulation in 6 patients undergoing anterolateral retroperitoneal approaches to the thoracolumbar junction. The authors confirmed T11 and T12 innervation of the anterolateral abdominal wall musculature by direct intraoperative EMG recording in all 6 patients.

Conclusions

The authors classified the 3 potential zones of injury that can be affected during an anterolateral approach to the thoracolumbar junction. Modifications to the operative technique are suggested to avoid the complication of flank bulge. The most significant intercostal nerve contributions to the anterolateral abdominal wall arise from T11 and T12.

Optochiasmatic cavernous angioma with rapid progression after biopsy despite radiation therapy

We present a rare case of optochiasmatic cavernous angioma (CA) that progressed despite radiation therapy. A 31-year-old female patient presented with sudden loss of left visual acuity and right homonymous hemianopsia. Magnetic resonance imaging (MRI) revealed a suprasellar mass and findings compatible with a craniopharyngioma or an optic glioma with bleeding. An open biopsy was conducted using the transcranial approach, and histological examination revealed gliosis. During the one-year follow-up period, imaging suggested intratumoral bleeding and the mass continued to grow. We recommended re-operation, but the patient refused due to fear of surgery. Consequently, the patient received fractionated radiation therapy (3,000 cGy) to the parasellar area. Despite the radiotherapy, the mass continued to grow for the following 6 years. The final MRI before definitive treatment revealed a multilobulated, multistage hematoma with calcification in the parasellar area, extending into the third ventricle and midbrain. The patient ultimately underwent reoperation due to the growth of the tumor. The mass was completely removed with transcranial surgery, and the pathologic findings indicated a cavernous angioma (CA) without evidence of glioma. As shown in our case, patients may suffer intratumoral hemorrhage after biopsy and radiotherapy. This case places the value of biopsy and radiotherapy for a remnant lesion into question. It also shows that reaching the correct diagnosis is critical, and complete surgical removal is the treatment of choice.

Ossification of the posterior longitudinal ligament: a review

Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, the elderly, and Asian patients. There are many diseases associated with OPLL, such as diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, and other spondyloarthropathies. Several factors have been reported to be associated with OPLL formation and progression, including genetic, hormonal, environmental, and lifestyle factors. However, the pathogenesis of OPLL is still unclear. Most symptomatic patients with OPLL present with neurological deficits such as myelopathy, radiculopathy, and/or bowel and bladder symptoms. There are some reports of asymptomatic OPLL. Both static and dynamic factors are related to the development of myelopathy. Plain radiography, CT, and MR imaging are used to evaluate OPLL extension and the area of spinal cord compression. Management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be made case by case, depending on the patient's condition, level of pathology, type of OPLL, and the surgeon's experience. In this paper, the authors attempt to review the incidence, pathology, pathogenesis, natural history, clinical presentation, classification, radiological evaluation, and management of OPLL.

Biodegradation of estrogen conjugates by bacteria isolated from river sediments

The objective of this study was to investigate the ability of E. coli in river sediments to degrade estrogen conjugates. Biodegradation experiments on glucuronide estrogens (E1-GLU, E2-GLU and E3-GLU) using E. coli, non-E. coli bacteria as well as sediment crude extracts were carried out in batch mode. A pure identified E. coli strain (KCTC 2571) was used for comparison of enzyme activity. The results showed that the degradation rate of estrogen conjugates by KCTC 2571 and E. coli isolated from sediments followed a similar trend. Fecal bacteria showed a high ability to deconjugate glucuronided estrogens. Approximately 50% of glucuronide moieties were cleaved within 4 h of contact time in experiments using pure E. coli. The degradation rate was slower in experiments using crude extracts of sediments, and conjugated estrogens were not completely degraded even after 12 h of reaction. These results provide a clear understanding of the fate and behavior of estrogen by bacteria in the environment.

Effect of preparation methods on toxicity of fullerene water suspensions to Japanese medaka embryos

The physicochemical properties of fullerene water suspensions (nC(60)) and their subsequent toxicity were influenced by different preparation methods. The nC(60) suspensions were produced by three methods: toluene exchange (Tol/nC(60)), DMSO dissolving (DMSO/nC(60)), and stirring overtime (Aqu/nC(60)). The particle size, zeta potential, and nC(60) structure were strongly dependent on both the type of aggregates formed and the test medium addition. Specifically, Tol/nC(60) exhibited small and spherical closed aggregates, whereas DMSO/nC(60) and Aqu/nC(60) presented mesoscale aggregates of smaller spherical aggregates. These differences in the physicochemical properties of nC(60) determined the embryonic toxicity and oxidative stress of Japanese medaka (Oryzias latipes). The mortality and glutathione (GSH) induction of embryos were ranked in the order of Tol/nC(60)>DMSO/nC(60)>Aqu/nC(60), and the morphological malformations were in the order of DMSO/nC(60)>Tol/nC(60)>Aqu/nC(60). The mortality of Tol/nC(60) was attributed to its closely packed fullerene structure, which remained as largely underivatized C(60). The malformations of DMSO/nC(60) might have originated from the co-effect of organic solvent remaining in the fullerene colloid. To summarize, these findings clearly illustrated the need to consider the effect of preparation method on the physicochemical properties when assessing nC(60) toxicity.

Role of arachidonic acid-derived metabolites in the control of pulmonary arterial pressure and hypoxic pulmonary vasoconstriction in rats

BACKGROUND

The roles of arachidonic acid (AA) metabolites in hypoxia-induced pulmonary vasoconstriction (HPV), a critical physiological mechanism that prevents ventilation/perfusion mismatch, are still incompletely understood.

METHODS

Pulmonary arterial pressure was measured in ventilated/perfused rat lungs. Isometric tones of rat intralobar pulmonary arteries were also measured, using a myograph.

RESULTS

Hypoxia (Po₂, 3%)-induced pulmonary arterial pressure increases (ΔPAP(hypox)) were stable with blood-mixed perfusate, but decayed spontaneously. ΔPAP(hypox) was inhibited by 29%, 16%, and 28% by the thromboxane A₂ (TXA₂) antagonist SQ-29548, the 5-lipoxygenase inhibitor, MK886, and the leukotriene D₄ antagonist, LY-171883, respectively. The prostacyclin synthase inhibitor tranylcypromine augmented ΔPAP(hypox) by 5%, whereas inhibition of cytochrome P450 did not affect ΔPAP(hypox). Consistently, the TXA₂ analogue U46619 increased ΔPAP(hypox) whereas prostacyclin abolished ΔPAP(hypox). However, leukotriene D₄ had no direct effect on ΔPAP(hypox). In the isolated pulmonary arteries, pretreatment with U46619 was essential to demonstrate hypoxia-induced contraction.

CONCLUSIONS

The above results suggest that TXA₂ and cysteinyl leukotrienes, other than leukotriene D₄, are endogenous factors that facilitate HPV in rats. The indispensable role of TXA₂-induced pretone in the HPV of isolated pulmonary arteries indicates that the signal from thromboxane receptors might be a critical component of oxygen sensation mechanisms.

Angiographic and clinical outcomes of stent-alone treatment for spontaneous vertebrobasilar dissecting aneurysm

PURPOSE

Spontaneous vertebrobasilar dissecting aneurysm (VBD) is a very challenging disease with an unpredictable clinical course and controversies on treatment strategy. The present study reports radiological and clinical outcomes of stent-alone treatment (SAT) for VBD.

METHODS

Twenty-four VBDs treated with SAT are included in the present study. Clinical and angiographic data were reviewed retrospectively.

RESULTS

A total of 24 lesions in 22 patients with a mean follow-up period of 16.21 months were included. Of the 24 individual lesions, 23 were intracranial vertebral artery lesions and 1 lesion was located in the basilar artery. There were six cases of ruptured dissections with the other cases having various symptoms. The immediate post-SAT angiographic outcomes included 5 lesions with good remodeling over 90% recovery and 19 poorly remodeled lesions. The latest angiographic outcomes included 17 cases of good remodeling (remodeling rate over 90%), 6 cases of poor remodeling (remodeling rate below 70%), and 1 case with morphological aggravation. The overlapping stent technique was used in seven cases and it was significantly associated with good angiographic results. None of the rupture cases underwent re-rupture post SAT. There was one case of a symptomatic complication of a femoral arteriovenous fistula.

CONCLUSIONS

The SAT could be a feasible alternative for the treatment of VBD. The overlapping technique was significantly associated with good angiographic outcome. We expect that technological development of the intracranial stent will allow better procedural outcomes of SAT.

Effect of perfluorooctanesulfonate on osmoregulation in marine fish, Sebastes schlegeli, under different salinities

Effect of potassium salt of perfluorooctane sulfonic acid (PFOS) on the osmoregulation of marine teleost (blackrock fish), Sebastes schlegeli, was investigated under varying salinities, by monitoring serum osmolality, Na(+), K(+), Cl(-), Ca(2+) and Mg(2+) concentrations in serum, serum glucose, and gill Na(+)-K(+) ATPase (NKA) activity. The fish was acclimatized to four salinity levels (10, 17.5, 25, and 34 psu) for 2 weeks before a 6-d exposure to 100 or 1000 microg L(-1) of PFOS. Six fish from each exposure group were sampled at 24, 48, and 144 h after exposures, and serum, liver and gills were collected for analysis. NKA activity decreased by 34% and 31% relative to control at salinity levels of 25 and 34 psu, respectively, following exposure to 1000 microg L(-1) PFOS. PFOS did not affect serum osmolality, Na(+), Cl(-), Ca(2+) and Mg(2+) concentrations; however, serum K(+) concentration increased during initial exposure period and then decreased after 144 h. Serum glucose levels decreased with increasing PFOS concentrations, implying high energy demand in response to exposure. Overall, PFOS exposure impaired NKA activity, altered potassium ion concentrations in serum, and reduced serum glucose levels while no other effects on serum concentrations of ionic salts were observed.

Sorption of estrogens onto different fractions of sediment and its effect on vitellogenin expression in male Japanese medaka

This study investigated the sorption capacity of estrogenic compounds-such as estrone (E1), 17beta-estradiol (E2), and 17alpha-ethynylestradiol (EE2)-of different sediment particle fractions. Two-sized fractions of sediment were used in the experiments, with a particle size <1 microm (mostly from 450 to 800 nm) and >1 microm up to 50 microm. Sorption kinetics were followed using a two-step reaction in which the major amount of chemicals was sorbed rapidly within minutes and then gradually increased until equilibrium was reached after 48 h. The sorption capacity of the fine particle fraction (particle size <1 microm) was shown to be significantly higher than that of the large fraction (1 microm < particle size < 50 microm). The sorption kinetics and isotherm were adequately predicted by using a pseudo second-order model and the Freundlich equation, respectively. Total organic carbon (TOC) content and surface area of particle fractions were also measured. Although the effects of TOC on the sorption of estrogens could not be verified, a higher surface area of fine particle fractions may significantly increase sorption capacity to target compounds. Sorption of estrogens onto sediment particles could be used to explain the differences of estrogenic activity of E2 spiked into different size fractions of particle suspensions.

Pseudomonas stutzeri YPL-1 Genetic Transformation and Antifungal Mechanism against Fusarium solani, an Agent of Plant Root Rot

An actively antagonistic bacterium that could be used as a biocontrol agent against Fusarium solani, which causes root rots with considerable losses in many important crops, was isolated from a ginseng rhizosphere and identified as a strain of Pseudomonas stutzeri. In several biochemical tests with culture filtrates of P. stutzeri YPL-1 and in mutational analyses of antifungal activities of reinforced or defective mutants, we found that the anti-F. solani mechanism of the bacterium may involve a lytic enzyme rather than a toxic substance or antibiotic. P. stutzeri YPL-1 produced extracellular chitinase and laminarinase when grown on different polymers such as chitin, laminarin, or F. solani mycelium. These lytic extracellular enzymes markedly inhibited mycelial growth rather than spore germination and also caused lysis of F. solani mycelia and germ tubes. Scanning electron microscopy revealed degradation of the F. solani mycelium. Abnormal hyphal swelling and retreating were caused by the lysing agents from P. stutzeri YPL-1, and a penetration hole was formed on the hyphae in the region of interaction with the bacterium; the walls of this region were rapidly lysed, causing leakage of protoplasm. Genetically bred P. stutzeri YPL-1 was obtained by transformation of the bacterium with a broad-host-range vector, pKT230. Also, the best conditions for the transformation were investigated.