Genetic divergence with ongoing gene flow is maintained by the use of different hosts in phytophagous ladybird beetles genus Henosepilachna.

Adaptation to different environments can promote population divergence via natural selection even in the presence of gene flow - a phenomenon that typically occurs during ecological speciation. To elucidate how natural selection promotes and maintains population divergence during speciation, we investigated the population genetic structure, degree of gene flow and heterogeneous genomic divergence in three closely related Japanese phytophagous ladybird beetles: Henosepilachna pustulosa, H. niponica and H. yasutomii. These species act as a generalist, a wild thistle (Cirsium spp.) specialist and a blue cohosh (Caulophyllum robustum) specialist, respectively, and their ranges differ accordingly. The two specialist species widely co-occur but are reproductively isolated solely due to their high specialization to a particular host plant. Genomewide amplified fragment-length polymorphism (AFLP) markers and mitochondrial cytochrome c oxidase subunit I (COI) gene sequences demonstrated obvious genomewide divergence associated with both geographic distance and ecological divergence. However, a hybridization assessment for both AFLP loci and the mitochondrial sequences revealed a certain degree of unidirectional gene flow between the two sympatric specialist species. Principal coordinates analysis (PCoA) based on all of the variable AFLP loci demonstrated that there are genetic similarities between populations from adjacent localities irrespective of the species (i.e. host range). However, a further comparative genome scan identified a few fractions of loci representing approximately 1% of all loci as different host-associated outliers. These results suggest that these three species had a complex origin, which could be obscured by current gene flow, and that ecological divergence can be maintained with only a small fraction of the genome is related to different host use even when there is a certain degree of gene flow between sympatric species pairs.

Regeneration and coexistence of two Abies species dominating subalpine forests in central Japan.

The mechanism of coexistence of the dominant firs Abies veitchii and A. mariesii is described in relation to regeneration patterns for climax subalpine forests of the northern Yatsugatake Mountains, central Honshu, Japan. Two mature stand types, pure conifer stands of Abies spp., and mixed stands of Abies spp. and hardwoods (mainly the birch Betula ermanii), are distinguished. Pure stands are likely to show simultaneous decay, followed by evenaged regeneration of stand-floor seedlings (<20 cm tall), Rapidly growing A. veitchii dominates over A. mariesii in this type of regeneration, which is occasionally invaded by light-demanding Betula. In constrast, mixed stands degenerate rather slowly, followed by the regeneration of Abies from the bank of suppressed saplings (>20 cm tall), which persist only in mixed stands. The more shade-tolerant A. mariesii is supeior in this type of regeneration, while Betula does not succeed, and mixed stands change to pure stands with time. The fact that two patterns of Abies regeneration occur in a certain ratio in the forest is what enables the two Abies species to coexist. A simple dynamical system model supports this conclusion.

Glucocorticoids and TGF-beta1 synergize in augmenting fibroblast mediated contraction of collagen gels.

TGF-beta plays a central role in the initiation and progression of pulmonary fibrosis. Glucocorticoids are frequently used to treat fibrotic diseases, but beneficial effects are often modest. Both TGF-beta and glucocorticoids have been reported to increase fibroblast contraction of native collagen gels, a model of fibrotic tissue remodeling. Therefore, we sought to determine how glucocorticoids interact with TGF-beta in this system. In this study, human fetal lung fibroblasts (HFL-1) were pretreated with or without TGF-beta for 72 h before they were cast into type I collagen gels. Various concentrations of glucocorticoids (budesonide or hydrocortisone) were added at the time of casting. Gel size was then monitored at different times after gel release. The surrounding media were collected for the assay of prostaglandin E2 (PGE2) and the cell lysates were analyzed for cyclooxygenase (COX) expression by immunoblot. Glucocorticoids alone significantly enhanced fibroblast-mediated contraction of collagen gels (P < 0.01) and dose-dependently inhibited PGE2 release by HFL-1 fibroblasts. TGF-beta significantly augmented gel contraction but also induced a 30% increase in PGE2 release and increased the expression of COX-1. Glucocorticoids inhibited TGF-beta1 induced-PGE2 release, and enhanced TGF-beta augmented gel contraction without significantly affecting TGF-beta augmented COX-1 expression. Indomethacin, a COX inhibitor, increased TGF-beta augmented gel contraction but had no further effect when added together with glucocorticoids. Thus, glucocorticoids can synergize with TGF-beta in augmenting fibroblast mediated collagen gel contraction through the inhibition of PGE2 production. Such interactions between glucocorticoids and TGF-beta may account, in part, for the lack of response of fibrotic diseases to glucocorticoids.

Persistence of TGF-beta1 induction of increased fibroblast contractility.

Fibroblast contraction of collagen gels is regarded as a model of wound contraction. Transforming growth factor (TGF)-beta added to such gels can augment contraction consistent with its suggested role as a mediator of fibrotic repair. Since fibroblasts isolated from fibrotic tissues have been suggested to express a "fibrotic phenotype," we hypothesized that TGF-beta exposure may lead to a persistent increase in fibroblasts' contractility. To evaluate this question, confluent human fetal lung fibroblasts were treated with serum-free Dulbecco modified Eagle medium (DMEM), with or without 100 pM [corrected] TGF-beta1, TGF-beta2, or TGF-beta3 for 48 h. Fibroblasts were then trypsinized and cast into gels composed of native type I collagen isolated from rat tail tendons. After 20 min for gelation, the gels were released and maintained in serum-free DMEM. TGF-beta-pretreated fibroblasts caused significantly more rapid gel contraction (52.5+/-0.6, 50.9+/-0.2, and 50.3+/-0.5% by TGF-beta1, -beta2, and -beta3 pretreated fibroblasts, respectively) than control fibroblasts (74.0+/-0.3%, P < 0.01). This effect is concentration dependent (50-200 nM), and all three isoforms had equal activity. The effect of TGF-beta1, however, persisted for only a short period of time following the removal of TGF-beta, and was lost with sequential passage. These observations suggest that the persistent increase in collagen-gel contractility, mediated by fibroblasts from fibrotic tissues, would not appear to be solely due to previous exposure of these cells to TGF-beta.

Isolation of SMTP-3, 4, 5 and -6, novel analogs of staplabin, and their effects on plasminogen activation and fibrinolysis.

Four novel triprenyl phenol metabolites, designated SMTP-3, -4, -5, and -6, have been isolated from cultures of Stachybotrys microspora IFO 30018 by solvent extraction and successive chromatographic fractionation using silica gel and silica ODS columns. A combination of spectroscopic analyses showed that SMTP-3, -4, -5, and -6 are staplabin analogs, containing a serine, a phenylalanine, a leucine or a tryptophan moiety in respective molecules in place of the N-carboxybutyl portion of the staplabin molecule. SMTP-4, -5, and -6 were active at 0.15 to 0.3 mM in enhancing urokinase-catalyzed plasminogen activation and plasminogen binding to fibrin, as well as plasminogen- and urokinase-mediated fibrinolysis. On the other hand, the concentration of staplabin required to exert such effects was 0.4 to 0.6 mM, and SMTP-3 was inactive at concentrations up to 0.45 mM.

Budding of crystalline domains in fluid membranes.

Crystalline domains embedded in fluid membrane vesicles are studied by Monte Carlo simulations of dynamically triangulated surfaces and by scaling arguments. A budding transition from a caplike state to a budded shape is observed for increasing spontaneous curvature C0 of the crystalline domain as well as increasing line tension lambda. The location of the budding transition is determined as a function of C0, lambda, and the radius R(A) of the crystalline domain. In contrast to previous theoretical predictions, it is found that budding occurs at a value of the spontaneous curvature C0, that is always a decreasing function of the domain size R(A). Several characteristic scaling regimes are predicted. The distribution of five- and sevenfold disclinations as the budding transition is approached is determined, and the dynamics of the generation of defects is studied.

Fatal pulmonary infection due to multidrug-resistant Mycobacterium kansasii which developed in an immunocompetent young man.

A 32-year-old immunocompetent man developed fever and malaise that persisted for three years. As he had no health insurance, he never received any medical treatment. On admission, chest X-ray revealed multiple cavitary lesions and his sputnum yielded acid-fast bacilli, that were identified as Mycobacterium kansasii with multidrug resistance. Although his general status improved transiently by antituberculous agents, he died of respiratory insufficiency after four months. The prognosis of Mycobacterium kansasii pulmonary disease is reported to be relatively good among non-tuberculous mycobacteriosis, however, physicians must pay careful attention to cases of delayed start of therapy or multidrug resistance, or both.

A novel antiallergic drug epinastine inhibits IL-8 release from human eosinophils.

Eosinophils are believed to be one of the important sources of cytokines at the site of allergic inflammation. A novel antiallergic agent epinastine showed a dose- and time-dependent suppressive effect on IL-8, one of the chemokines for eosinophils, released from eosinophils isolated from atopic diseases. The time-dependent accumulation of IL-8 inhibited by cycloheximide and the evaluation of the IL-8 mRNA levels by reverse transcriptase-polymerase chain reaction suggested that its action occurred in the posttranscriptional processes. It was suggested that epinastine might prevent the autocrine cycle for recruitment of human eosinophils by inhibiting IL-8 release from these cells.

Fourteen-member macrolides inhibit interleukin-8 release by human eosinophils from atopic donors.

Macrolide antibiotics such as erythromycin have been reported to be effective for asthma. However, the precise mechanisms of this effect remain unclear. We studied the effect of erythromycin, clarithromycin, josamycin, and other antibiotics on the release by eosinophils of interleukin-8 (IL-8), a potent chemokine for inflammatory cells, including eosinophils themselves. Human eosinophils were isolated from atopic patients, and the effects of the drugs on IL-8 release were evaluated. Only 14-member macrolides (erythromycin and clarithromycin) showed a concentration-dependent suppressive effect on IL-8 release (control, 100%; erythromycin at 1 microgram/ml, 67.82% +/- 3.45% [P < 0.01]; clarithromycin at 5 micrograms/ml, 56.81% +/- 9.61% [P < 0.01]). The effect was found at therapeutic concentrations and appeared to occur at the posttranscriprtional level. In contrast, a 16-member macrolide (josamycin) had no significant effect. We suggest that 14-member macrolides inhibit IL-8 release by eosinophils and may thereby prevent the autocrine cycle necessary for the recruitment of these cells into the airways.

A potent immunosuppressant FK506 inhibits IL-8 expression in human eosinophils.

FK506, a potent immunosuppressant, has attracted attention for its potential effectiveness in allergic diseases. Although eosinophils are believed to be one of the important effector cells at the site of allergic inflammation, there have been few reports about the direct effect of FK506 on eosinophils. In the present study, we evaluated if FK506 had any effect on the production of IL-8, one of the important chemokines for a variety of inflammatory cells, from human peripheral eosinophils. Purified eosinophils constitutively released IL-8, which was increased with calcium ionophore (10(-6) M). FK506 showed a dose-dependent suppressive effect on IL-8 production by eosinophils stimulated with calcium ionophore, but showed no effect on unstimulated cells. Evaluation of IL-8 mRNA levels by reverse transcription and polymerase chain reaction demonstrated that FK506 suppressed IL-8 gene expression only in activated eosinophils. FK506 further showed a suppressive effect on eotaxin and MCP-1 release from eosinophils. These findings suggested that FK506 might prevent infiltration of inflammatory cells such as eosinophils by, at least in part, inhibiting chemokine release from eosinophils.

[Importance of interstitial lung disease in collagen vascular disease: analysis of outcome].

We studied length of survival and related clinical findings in 715 inpatients with collagen-vascular diseases (1984 through 1994), the diagnostic Kaplan-Meier analysis showed that patients with polymyositis/dermatomyositis and those with systemic sclerosis did not survive as long as those with other types of collagen-vascular disease. Of the patients who died 37% died of respiratory failure due to interstitial lung disease. Patients with interstitial lung disease had better outcomes than did those with idiopathic interstitial pneumonia: they were younger, had higher initial vital capacities, and fewer episodes of acute exacerbation of lung disease than did those with idiopathic interstitial pneumonia. Among patients with interstitial lung disease, those who died of polymyositis/dermatomyositis did so within 1 year, but those who died of systemic sclerosis lived longer. Interstitial lung disease is an important prognostic factor in collagen-vascular disease, and needs further evaluation.

[Primary pulmonary non-Hodgkin's lymphoma in a patient with dermatomyositis].

A 47-year-old man with dermatomyositis and interstitial pneumonia had been treated with prednisolone since May, 1992, and with azathioprine since April, 1993. During the sixth month of this treatment, primary pulmonary non-Hodgkin's lymphoma (T-cell, diffuse, pleomorphic) developed. Chemotherapy (vincristine and adriamycin) was begun but there was no response. An invasive lesion of the brain was seen on a CT image. Despite cranial radiotherapy, the patient died of respiratory suppression due to progressive brain disease on December 14, 1993. Primary pulmonary non-Hodgkin's lymphoma develops only rarely in patients with dermatomyositis. In this case, oncogenesis may have been related to the use of immunosuppressants.

Interactions between monocytes and smooth-muscle cells can lead to extracellular matrix degradation.

BACKGROUND: Chronic infiltration of the airway wall with inflammatory cells characterizes both asthma and chronic bronchitis. Remodeling of the airway wall is also a feature of both diseases. OBJECTIVE: We hypothesized that collagen degradation may take place during coculture of monocytes with smooth-muscle cells (SMCs) and that this degradation might be altered by agents that modify the inflammatory regimen. METHODS: Monocytes (4.5 x 10(5)/mL) were cast into collagen gels containing human airway SMCs (4.5 x 10(5)/mL) and released into serum-free Dulbecco's modified Eagle's medium containing neutrophil elastase. Collagen content was quantified as total insoluble hydroxyproline on day 5. Zymography and immunoblotting were used to detect matrix metalloproteinases. RESULTS: Monocytes cocultured with SMCs in 3-dimensional native type I collagen gels produced TNF-alpha and IL-1beta and resulted in collagen degradation (30.5 vs 17.9 mg per gel) through inducing matrix metalloproteinase 1, 2, and 9 by means of SMCs. PGE(2) was significantly increased in coculture (0.9 vs 10.5 ng/mL). Indomethacin (1 micromol/L) completely inhibited PGE(2) production but augmented collagen degradation (17.9 vs 2.3 microg per gel), and this was blocked by the addition of exogenous PGE(2). Dexamethasone also inhibited collagen degradation in coculture. CONCLUSION: The current study supports the concept that interactions among cells present in the airway inflammatory milieu that characterize airway disease can lead to alterations in tissue structure and suggests mechanisms by which therapeutic strategies can be designed to modify tissue remodeling.

Potentiation of human lung fibroblast chemotaxis by the thromboxane A(2) analog U-46619.

Fibroblast production of extracellular matrix is crucial not only for normal tissue development and maintenance of tissue structure but also for the repair and remodeling processes after injury. Thromboxane A(2) (TXA(2)) is a potent mediator in inflammatory processes. The aim of this study was to investigate the effect of TXA(2) on chemotaxis of human fetal lung (HFL-1) fibroblasts induced by human plasma fibronectin or platelet-derived growth factor BB (PDGF-BB). By using the blindwell chamber technique, the TXA(2) agonist U-46619 alone had no chemotactic activity. However, U-46619 (200 nmol/L) stimulated HFL-1 fibroblast chemotaxis to human plasma fibronectin (20 microg/mL; 161.8% +/- 13.4%; P <.005) and to PDGF-BB (10 ng/mL; 188.5% +/- 7.0%; P <.005). Checkerboard analysis of human plasma fibronectin-directed migration confirmed that the TXA(2) agonist increased both chemotaxis and chemokinesis. The stimulatory effect of the TXA(2) agonist was concentration dependent and increased with time. Another agent known for stimulating the protein kinase C pathway, phorbol 12-myristate 13-acetate (10(-8) mol/L), had a similar effect, stimulating chemotaxis to fibronectin (146.2% +/- 8.6%). The stimulatory effect of the TXA(2) agonist on HFL-1 fibroblast chemotaxis was inhibited by the synthetic thromboxane receptor antagonist SQ29,548 (10(-5) mol/L) and the protein kinase C inhibitor calphostin (10(-7) mol/L). In summary, TXA(2) appears to stimulate fibroblast chemotaxis to fibronectin and PDGF, perhaps by modulating the rate of fibroblast migration. Such an effect may contribute to regulation of wound healing and the development of fibrotic disorders.

Erythromycin and clarithromycin attenuate cytokine-induced endothelin-1 expression in human bronchial epithelial cells.

Erythromycin and its fourteen-member macrolide analogues have attracted attention for their efficacy in bronchial asthma. However, their mechanisms of action remain unclear. We evaluated the effects of the macrolide antibiotics on endothelin-1 (ET-1) expression in normal and transformed human bronchial epithelial cells, one of the sources of this potent bronchoconstrictor important in the pathogenesis of asthma. Human bronchial epithelial cells were obtained from the resected bronchi, and the effect of several antimicrobial and antiasthmatic drugs on the production and messenger ribonucleic acid (mRNA) levels of ET-1 was evaluated. Bronchoepithelial cells were also isolated from the mucosa of asthmatic patients under fibreoptic bronchoscopy, and the modulating effects of the drugs were studied. Erythromycin and clarithromycin uniquely suppressed mRNA levels as well as the release of ET- at therapeutic and non-cytotoxic concentrations (percentage inhibition of ET-1 protein release: 26.4+/-5.22% and 31.2+/-7.45%, respectively, at 10(-6) M). Furthermore, erythromycin and clarithromycin inhibited ET-1 expression in bronchoepithelial cells from patients with chronic, stable asthma. A glucocorticosteroid, dexamethasone, also inhibited ET-1 expression. In contrast, theophylline, salbutamol and FK506 had no effect on ET-1 production. Our findings demonstrated that these fourteen-member macrolide antibiotics had an inhibitory effect on endothelin-1 expression in human bronchial epithelial cells. Moreover, this new mode of action may have some relevance to their clinical efficacy in bronchial asthma.

Prostaglandin D2 inhibits fibroblast migration.

Fibroblasts play an important role in the repair and remodelling processes following injury. Prostaglandin D2 (PGD2) is a potent mediator in inflammatory processes. In this study, the effect of the PGD2 on human foetal lung fibroblasts (HFL-1) chemotaxis induced by human plasma fibronectin (HFn) was investigated using the blindwell chamber technique. PGD2 inhibited HFL-1 chemotaxis to HFn (20 microg x mL(-1)) by 20.8 +/- 3.8% (p<0.05). Checkerboard analysis of HFn-directed migration confirmed that PGD2 inhibited both chemotaxis and chemokinesis. The effect of PGD2 was concentration-dependent and the inhibitory effect diminished with time. The PGD2 receptor (DP) agonist BW245C (500 nM) had a similar effect, inhibiting chemotaxis to 39.4 +/- 6.3%. The inhibitory effects of both PGD2 and BW245C on HFL-1 chemotaxis were blocked by the DP receptor antagonist AH6809 (2 microM). The inhibitory effect of PGD2 on fibroblast chemotaxis was also blocked by the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) inhibitor, KT5720, suggesting a DP receptor-initiated, cAMP-dependent effect mediated by PKA. Prostaglandin D2 appears to inhibit fibroblast chemotaxis, perhaps by modulating the rate of fibroblast migration. Such an effect may contribute to regulation of the wound healing response following injury in asthma patients.

Eosinophil adhesion to human bronchial epithelial cells: regulation by cytokines.

BACKGROUND: Eosinophil infiltration into the airways and interaction with bronchial epithelial cells are important in the pathogenesis of asthma. The purpose of the present study was to elucidate the regulatory mechanisms of eosinophil adhesion to human bronchial epithelial cells. METHODS: We cultured a human bronchial epithelial cell line, BEAS-2B, on a collagen-coated glass slide. Highly purified human eosinophils were added to each well to allow attachment to epithelium for 30 min. The number of attached eosinophils was counted. RESULTS: Eosinophil adhesion to epithelial cells was increased when the BEAS-2B cells were pretreated with interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Although IFN-gamma upregulated ICAM-1 expression as shown by flow cytometry, specific neutralizing antibody to ICAM-1 failed to block eosinophil adhesion. Dexamethasone significantly suppressed eosinophil adhesion to bronchial epithelial cells. CONCLUSION: Eosinophil adhesion to bronchial epithelium was dynamically regulated by cytokines, and this process might be a target for therapeutic intervention in the treatment of asthma.

Thrombin induces collagen gel contraction partially through PAR1 activation and PKC-epsilon.

The ability of fibroblasts to contract three-dimensional collagen gels has been used as an in vitro model of the tissue contraction which characterises both normal repair and fibrosis. Among its actions, thrombin can activate the protease-activated receptor (PAR)1 and, thereby, stimulate inflammation and repair. The current study evaluated whether thrombin could stimulate fibroblast-mediated collagen gel contraction by activating PAR1 and whether its downstream signalling depends on protein kinase C (PKC)-epsilon. Human foetal lung fibroblasts (HFL-1) were cultured in three-dimensional collagen gels and the area of the gels was measured by image analyser. Both thrombin and TFLLR, a selective PAR1 agonist, stimulated collagen gel contraction mediated by HFL-1. After RNA interference-mediated PAR1 knockdown in HFL-1, both thrombin and the PAR1 agonist-induced gel contraction were partially inhibited (by 22.4+/-2.2% and 17.6+/-5.6%, respectively). The gel contraction stimulated by thrombin was also reduced by a nonspecific PKC inhibitor and a calcium-independent PKC-epsilon inhibitor. Both thrombin and TFLLR significantly increased PKC-epsilon activity, and this effect was blocked by PAR1 knockdown. Thrombin stimulates collagen gel contraction at least partially through activation of protease-activated receptor 1 and protein kinase C-epsilon, and may contribute to tissue remodelling in inflammatory airway and lung diseases.