Plasma blob generation due to cooperative elliptic instability

Using fast-camera measurements the generation mechanism of plasma blobs is investigated in the linear device CSDX. During the ejection of plasma blobs the plasma is dominated by an m=1 mode, which is a counterrotating vortex pair. These flows are known to be subject to the cooperative elliptic instability, which is characterized by a cooperative disturbance of the vortex cores and results in a three-dimensional breakdown of two-dimensional flows. The first experimental evidence of a cooperative elliptic instability preceding the blob-ejection is provided in terms of the qualitative evolution of the vortex geometries and internal wave patterns.

Generation of a sheared plasma rotation by emission, propagation, and absorption of drift wave packets

Collisional electron drift wave turbulence generates drift wave packet structures with density and vorticity fluctuations in the central plasma pressure gradient region of a linear plasma device. Tracking these packets reveals that they follow an outward directed spiral-shaped trajectory in the (r,θ) plane, are azimuthally stretched, and develop anisotropy as they approach an axisymmetric, radially sheared azimuthal flow located at the plasma boundary. Nonlinear energy transfer measurements and time-delay analysis confirm that structure absorption amplifies the sheared flow. Similar mechanisms likely operate at the edge of confined toroidal plasmas and should lead to the amplification of sheared flows at the boundary of these devices as well.

Progression to insulin deficiency in Korean patients with Type 2 diabetes mellitus positive for anti-GAD antibody

AIMS

To investigate the rate of progression to insulin deficiency in Korean patients with Type 2 diabetes mellitus positive for anti-GAD antibody (GADA) and to determine the factors related to progression to insulin deficiency.

METHODS

We retrospectively analysed data on 87 GADA-positive and 87 age- and sex-matched GADA-negative patients with Type 2 diabetes. GADA-positive patients were further subclassified into high-titre (≥ 250 WHO units/ml) (n = 24) and low-titre (< 250 WHO units/ml) (n = 63) subgroups. Cox proportional hazard analysis was used to identify factors associated with progression to insulin deficiency.

RESULTS

Over a period of 6 years, two of 87 (2.3%) GADA-negative and 37 of 87 (42.5%) GADA-positive patients had progressed to insulin deficiency. The rate of progression to insulin deficiency was higher in the high-titre than in the low-titre subgroup (75.0 vs. 30.2%). Multivariate analysis in GADA-positive patients showed that high-titre GADA and low BMI at diagnosis were independent factors significantly related to progression to insulin deficiency.

CONCLUSIONS

The presence of GADA predicted the progression to insulin deficiency in Korean patients with Type 2 diabetes. In GADA-positive patients, high-titre GADA and low BMI were associated with this progression.

Valve replacement in pediatric patients: a single center experience

BACKGROUND

Reconstructive surgery is the primary goal in pediatric patients with valve disease. However, in cases with irreparable valve lesions, valve replacement is the only option. This study aimed to retrospectively analyze the clinical experience of heart valve prosthesis replacement in children.

METHODS

Between January 1990 and July 2009, 35 pediatric patients (16 boys, 19 girls) underwent mechanical valve replacement in Shandong University Qilu Hospital. The ages ranged from 2.5 to 14 years (mean, (8.8 ± 3.8) years) and body weight varied from 11 to 37 kg (mean, (22.1 ± 5.2) kg). Mechanical valve replacement was performed because of congenital heart disease in 23 patients, rheumatic disease in ten patients and infective endocarditis in two patients. St. Jude bileaflet mechanical valves were implanted in all the 35 patients including mitral valve replacement (MVR) in 18, aortic valve replacement (AVR) in 12, tricuspid valve replacement (TVR) in two, AVR and MVR in two and MVR and TVR in one. The size of the prostheses ranged between 19 and 27 mm. All patients received long-term anticoagulation treatment with sodium warfarin, aiming to maintain an international normalized ratio between 1.5 to 2.0. Follow-up was performed in all the patients with a total follow-up of 119.4 patient-years.

RESULTS

The operative mortality was 8.57% (3/35). One patient, who underwent cardiac debridement and AVR, died 2 hours after being admitted to the intensive care unit because of severe low cardiac output syndrome and ventricular fibrillation. Two patients died of cardiogenic shock and renal failure during initial hospitalization after the operation. One patient who received replacement of a tricuspid valve developed complete heart block requiring temporary pacing and recovered sinus rhythm 4 days later. Thirty-two patients survived and their cardiac function was in New York Heart Association (NYHA) class I to class II when discharged. Late events included hemorrhage and endocarditis. Two patients required reoperation. No late deaths occurred during the follow-up.

CONCLUSIONS

Mechanical valve replacement remains an acceptable treatment option in children when the valve reparation is impossible or unsuccessful. The operative mortality and incidence of any valve-related events such as endocarditis, reoperation, thromboembolism or anticoagulation-related bleeding are acceptable.

[Prognostic analysis of 336 patients with chronic severe hepatitis B]

OBJECTIVE

To investigate the risk factors related to outcome of chronic severe hepatitis B.

METHODS

A total of 336 consecutive patients with chronic severe hepatitis B (CSHB) were analysed retrospectively. According to the outcome, objects were divided into survival group (n = 137) and death group(n = 199), then to observe the differences between them in respect to age, sex, family history, prothrombin activity (PTA), complications including ascites, infection, electrolyte disturbance, upper gastrointestinal bleeding, hepatic encephalopathy, hepatorenal syndrome and the corresponding quantity of complications in each individual, antivirus therapy, artificial liver support system (ALSS) therapy, and alprostadil therapy. Finally, risk factors related to prognosis were selected by stepwise Logistic regression analyse.

RESULTS

In univariate analyse, significant differences between the two groups were found related to age, PTA, complications and its quantity (P < 0.01 for all), and antivirus therapy (P < 0.05) rather than sex, family history and treatment of ALSS or alprostadil. Logistic regression revealed that risk factors comprised of PTA and quantity of complications, antivirus therapy was the only protective factor.

CONCLUSION

A numbers of factors including age, PTA, complications and its quantity, and antivirus therapy affect the prognosis of CSHB, among which, antivirus therapy can reduce the death rate.

[Study on the changes of the T-lymphocyte subsets and their significance in influenza A (H1N1) virus patients]

OBJECTIVE

To study the changes of T-Lymphocyte and activated T-Lymphocyte subsets in influenza A (H1N1) virus patients.

METHODS

The percentages of the subsets of Lymphocyte were detected by flow cytometry in influenza A (H1N1) virus patients (n = 144) and normal controls (n = 41). Furthermore, the subsets of T-Lymphocyte and activated T-lymphocyte were analyzed in 83 among those patients before and after treatment.

RESULTS

Compared with the control group, the counts of Lymphocyte in patients with influenza A (H1N1) virus was significantly discreased, the counts of Lymphocyte in patients with influenza A virus concurrent pneumonia was significantly discreased those of no concurrent pneumonia; Compared with the control group, the percentage of T-lymphocyte in patients with influenza A virus concurrent pneumonia was significantly discreased. The counts and percentage of CD3 and CD8 cells was significantly discreased in patients (n = 83) before treatment; The counts of CD4 cells was significantly discreased before treatment. The percentage of HLA-DR+ CD+, HLA-DR+ CD4+ and HLA-DR+ CD8+ cells was significantly discreased in patients (n = 83) before treatment.

CONCLUSIONS

To understand the expression of the T-Lymphocyte and activated T-Lymphocyte subsets in influenza A (H1N1) virus patients may help to evaluate the patients' cellular immune status, but also be a guideline of early diagnosis of Influenza A (H1N1) virus.

Intrinsic rotation from a residual stress at the boundary of a cylindrical laboratory plasma

An azimuthally symmetric radially sheared azimuthal flow is driven by a nondiffusive, or residual, turbulent stress localized to a narrow annular region at the boundary of a cylindrical magnetized helicon plasma device. A no-slip condition, imposed by ion-neutral flow damping outside the annular region, combined with a diffusive stress arising from turbulent and collisional viscous damping in the central plasma region, leads to net plasma rotation in the absence of momentum input.

[The expression of CD95 and activated antigens in peripheral blood lymphocyte subsets in patients with hand foot and mouth disease (HFMD)]

OBJECTIVE

To investigate the expression of CD95 and special marker for activation of peripheral blood lymphocytes in patients with hand foot and mouth disease (HFMD) and its significance.

METHODS

Immunofluorescent two-color flow cytometry was used to study the expression of CD95 and HLA-DR on lymphocytes in 58 patients with HFMD and 34 normal controls.

RESULTS

Expression of CD3+ T cells was significantly lower in patients (63.82 +/- 7.74)% than that in controls (P < 0.001), meanwhile the expression of CD4+ T cells was (34.29 +/- 7.33)%, significantly lower than that of the controls (P < 0.005). The percentage of lymphocytes expressing HLA-DR in patients was (23.77 +/- 5.78)%, significantly higher than that of the controls (P < 0.005). Significant difference was observed in the expression of HLA- DR on CD8+ T cells in patients (1.34 +/- 1.12)% as compared with controls (P < 0.005). No significant difference in the expression of CD95 on lymphocytes was observed between patients and the controls (P > 0.05).

CONCLUSION

The findings support that cellular immunodeficiency exists in patients and that lymphocytes were abnormally activated in the patients. The activation of peripheral blood T lymphocytes in patients mainly involves CD8 subset and it may play an important role in the immune response to antiviral infection.

[Comparative study on the immunogenicity of human homologous cardiac valve and great artery homograft cryopreserved with liquid nitrogen]

OBJECTIVE

To study the differences on the immunogenicity of the leaflets, arterial wall and myocardium of conduit valved homograft (CVH) cryopreserved with liquid nitrogen.

METHODS

Mono-cell suspension of leaflets cells and arterial cells of CVH were respectively co-cultured with human lymphatic cells whose blood groups were the same with that of CVH donors. Expressive levels of CD25 and HLA-DR of these lymphatic cells were detected by flow cytometry in the different cultural duration and compared with that of lymph cells alone cultured (comparative group).

RESULTS

The immunogenicity of CVH artery walls was more severe than that of CVH leaflets, and expressive level of whose CD25 and HLA-DR was higher. The immunogenicity of CVH myocardium was not studied because the myocardial cell suspension were not be acquired in this study.

CONCLUSION

It is proved that in vitro experimental study that the immunogenicity of arterial walls of cryopreserved CVH is more severe than that of leaflets.

[Impact of shengmal injection on changes of immunological function in patients after cardiopulmonary bypass]

OBJECTIVE

To study the impact and mechanism of Shengmai Injection (SMI) on the immunological function changes after cardiopulmonary bypass.

METHODS

Forty patients with rheumatic heart valve disease were selected and assigned randomly to two groups: 20 in the control group and 20 in the SMI group. Peripheral blood samples were taken at various time points, i.e. 3 days before operation (T1), 10 min after terminal of CPB (T2), the first (T3), third (T4), and seventh (T5) day after operation, for counting white blood cell (WBC), neutrophils and lymphocytes; percentage of T lymphocytes (CD3+ mononuclear cells) and its subsets (CD4+ and CD8+) to calculate CD4+/CD8+ ratio; and the serum content of immunoglobulins (IgG, IgA, IgM) as well as serum concentration of interleukin-8 (IL-8) and interleukin-10 (IL-10) were assayed.

RESULTS

Compared with the control group, in the SMI group, WBC and neutrophil count were lower at T2 (P < 0.01); percentages of CD3+ and CD4+ lower at T4 and T5 (P < 0.05 or P < 0.01); percentage of CD8+ higher at T2 to T5 (P < 0.05 or P < 0.01); CD4+/CD8+ ratio lower at T3 to T5 (P < 0.05 or P < 0.01); IgG lower at T2 (P < 0.05); IgA higher at T3 (P < 0.05); IgM higher at T3 to T5 (P < 0.05); IL-8 lower at T2 to T4 (P < 0.05); and IL-10 higher at T2 (P < 0.05).

CONCLUSION

Application of SMI in the perioperative period can enhance the humoral immunity and inhibit the cellular immunity after CPB, it could also reduce the systemic inflammatory reaction and improve the prognosis of patients.

Spectrally filtered fast imaging of internal magnetohydrodynamic activity in the DIII-D tokamak

The detailed poloidal structure of internal magnetohydrodynamic (MHD) modes is imaged using broadband visible bremsstrahlung emission from the core of the DIII-D tokamak. Spectral analysis of individual pixel time series recorded by a fast framing camera (up to 26,000 frames/s at 256x256 spatial resolution) is used to reconstruct two-dimensional images of mode amplitude. Application of this spectrally filtered fast imaging (SFFI) technique reveals spatially extended coherent structures that correspond to a (m,n)=(1,1) kink mode and a (2,1) neoclassical tearing mode rotating in the laboratory frame. The SFFI technique produces images with significantly less noise than images produced with the commonly used background subtraction method. Extension of SFFI to other core MHD events and coherent fluctuations in general is straightforward and could lead to further understanding of core MHD activity in fusion devices.

Dust measurements in tokamaks (invited)

Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 microm in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C(2) dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

[Curcumin inhibits the expression of vascular endothelial growth factor and androgen-independent prostate cancer cell line PC-3 in vitro]

OBJECTIVE

To study the effects of curcumin on the expression of the vascular endothelial growth factor (VEGF) and androgen-independent prostate cancer cell line PC-3, and to explore its anticarcinogenic mechanism.

METHODS

PC-3 cells were treated with curcumin at the concentration of 0, 6.25, 12.5, 25 and 50 micromol/L respectively. Then the cell activity was assayed by dyed rate of Typan blue and MTT at 12, 24, 36, 48, 72 and 96 hours, the cell cycle and morphological changes observed by flow cytometry (FCM) and electronic microscopy at 24 hours, the VEGF mRNA expression measured by semi-quantitative RT-PCR, and the secreting protein levels of VEGF in the supernatants determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The growth of PC-3 cells was suppressed obviously by curcumin in a dose- and time-dependent manner in vitro. There were significant differences in inhibition rate among different concentration and time groups (P < 0.01). Furthermore, curcumin arrested the cell cycle of PC-3 cells in the G2/M phase in a dose-dependent manner (P < 0.01). The percentages of apoptotic cells were significantly higher in different concentration groups than in the controls (P < 0.01). Apoptosis-associated morphological changes were observed in PC-3 cells at 24 hours, and a marked decline in the expression of VEGF was noted after the exposure to different concentrations of curcumin within 24 hours.

CONCLUSION

Curcumin can suppress the growth of PC-3 cells, promote their apoptosis and arrest their cell cycle in the G2/M phase, and reduce the expression of VEGF mRNA and proteins, which may sever to explain its inhibitory effect on tumor and angiogenesis.

Observation of turbulent-driven shear flow in a cylindrical laboratory plasma device

An azimuthally symmetric radially sheared plasma fluid flow is observed to spontaneously form in a cylindrical magnetized helicon plasma device with no external sources of momentum input. A turbulent momentum conservation analysis shows that this shear flow is sustained by the Reynolds stress generated by collisional drift turbulence in the device. The results provide direct experimental support for the basic theoretical picture of drift-wave-shear-flow interactions.

[Curcumin-induced apoptosis in androgen-dependent prostate cancer cell line LNCaP in vitro]

OBJECTIVE

To explore the apoptosis induction by curcumin in androgen-dependent prostate cancer cell line LNCaP).

METHODS

After LNCaP cells were induced by 10, 25, 50, 75, 100 micromol/L curcumin respectively, the cell activity was assayed by MTT at 5, 12 and 24 hours. Flow cytometry and electronic microscopy were adopted to observe cell cycle and morphological changes of LNCaP cells at 24 hours. After 5 hours, the expression of IkappaBalpha in LNCaP cells was detected by Western blotting.

RESULTS

The growth of LNCaP cells was suppressed obviously by curcumin in dose-dependent and time-dependent manners in vitro. There were significant differences in inhibition rate among different concentrations and time groups (P < 0.05). Furthermore, curcumin could arrest the cell cycle of LNCaP cells at G2/M phase in a dose-dependent manner (P <0.01). The ratios of apoptosis were significantly higher than those of controls (P < 0. 5). Curcumin could lead to characteristic morphological changes of apoptosis in LNCaP cells after 24 hours. The expression of IkappaBalpha in LNCaP cell did not show marked changes after the exposure to different concentrations of curcumin within 5 hours.

CONCLUSION

Curcumin can suppress the growth of LNCaP, and promotes their apoptosis.

Fluid echoes in a pure electron plasma

Experimental observations of diocotron wave echoes on a magnetized electron column are reported, representing Kelvin wave echoes on a rotating near-ideal fluid. The echoes occur by reversal of an inviscid wave damping process, and the phase-space mixing and unmixing are directly imaged. The basic echo characteristics agree with a simple nonlinear ballistic theory. At late times, the echo is degraded, and the maximal observed echo times agree with a theory of electron-electron collisions acting on separately evolving velocity classes.

[Application of one-way valved patch in treatment of patients with congenital heart disease with severe pulmonary hypertension]

OBJECTIVE

To explore the effect of one-way valved patch used in congenital heart disease with severe pulmonary hypertension.

METHODS

One-way valved patch was used in 30 patients of congenital heart disease with severe pulmonary hypertension (PP/PS > 0.75) in operation. Follow-up of 6 approximately 86 months was conducted to observe its effect.

RESULTS

The pulmonary artery pressure was significantly decreased without trans-patch shunt in 11 cases postoperatively. Trans-patch shunt was determined in 27 cases within postperative 72 hours. There were 2 postoperative deaths out of these 27 patients: one died of low cardiac output syndrome 72 hours after operation, and the other died of right heart failure 4 weeks after operation. Thirty-six patients were restored to health and discharged. Three-month follow-up showed trans-patch shunt in 7 cases, including right-to left shunt in 4 cases and two-side shunt in other 3 cases. Color Doppler ultrasonography conducted 6 months after operation proved trans-patch shunt in 4 cases, right-to-left shunt in 1 case, two-side shunt in 2 cases, and left-to-right shunt in 1 case (PP/PS = 0.45).

CONCLUSION

One-way valved patch is useful in selected patients in which postoperative right heart failure can be anticipated so as to shunt the blood in the right heart to the left heart and increase the blood volume in the left heart system to ensure the left heart output and minimize the risk of postoperative right heart failure, at the expense of systemic low oxygen saturation that is, however, well tolerated.

Rapid habituation of hippocampal serotonin and norepinephrine release and anxiety-related behaviors, but not plasma corticosterone levels, to repeated footshock stress in rats

Prior stress exposure is known to alter the activation response to a subsequent stressor. In the present study, we examined neurochemical, neuroendocrinological, and behavioral correlates of short-term adaptation to homotypic stressors administered 60 min apart. An initial electric footshock significantly induced extracellular levels of both serotonin (5-HT) and norepinephrine (NE) in the rat hippocampus (650% and 200% above baseline, respectively), as measured by in vivo microdialysis. A rapid habituation in this response was evident in the inability of a second footshock to evoke similar increases. In contrast, the hypothalamic-pituitary-adrenal (HPA) response was augmented further after the second shock session: plasma corticosterone (CORT) levels were 18.1, 316.5, and 441.6 mg/ml in nonstressed, one-footshock-, or two-footshock-treated rats, respectively. In a social interaction paradigm, rats subjected to a single footshock showed several fear- and anxiety-related behaviors such as increases in freezing and decreases in rearing and active approach for social interaction. Exposure to a second footshock completely blocked the freezing response and restored rearing behavior without affecting the disruption in social interactions. Taken together, these data raise the possibility that neurochemical and neuroendocrine adaptations to short-term homotypic stressors differentially contribute to expression of different fear and anxiety-like responses in the rat.

Recruitment of a repressosome complex at the growth hormone receptor promoter and its potential role in diabetic nephropathy

The growth hormone (GH)-GH receptor (GHR) axis modulates growth and metabolism and contributes to complications of diabetes mellitus. We analyzed the promoter region of the dominant transcript (L2) of the murine GHR to determine that a cis element, L2C1, interacts with transcription factors NF-Y, BTEB1, and HMG-Y/I. These proteins individually repress GHR expression and together form a repressosome complex in conjunction with mSin3b. The histone deacetylase inhibitor trichostatin A increases expression of the murine GHR gene, enhances association of acetyl-H3 at L2C1, inhibits formation of the repressosome complex, and decreases NF-Y's association with L2C1. Our studies reveal that murine models of experimental diabetes mellitus are characterized by reduced hepatic GHR expression, decreased acetyl-H3 associated with L2C1, and increased formation of the repressosome complex. In contrast, in the kidney diabetes mellitus is associated with enhanced GHR expression and lack of alteration in the assembly of the repressosome complex, thus permitting exposure of kidneys to the effects of elevated levels of GH in diabetes mellitus. Our findings define a higher-order repressosome complex whose formation correlates with the acetylation status of chromatin histone proteins. The delineation of the role of this repressosome complex in regulating tissue-specific expression of GHR in diabetes mellitus provides a molecular model for the role of GH in the genesis of certain microvascular complications of diabetes mellitus.

Using a stages of readiness model to address community capacity on tobacco control in the Asian American and Pacific Islander community

OBJECTIVES

This paper describes the Asian Pacific Partners for Empowerment and Leadership (APPEAL) Stages of Community Readiness Model, a framework for assessing and evaluating tobacco control in the diverse Asian American and PaCific Islander (AAPI) communities.

METHODS

This model extends the work of existing community capacity models by applying a "stage of readiness" continuum of the five stages of pre-contemplation, contemplation, preparation, action and maintenance in terms of developing, launching and sustaining AAPI tobacco control efforts.

FINDINGS

The APPEAL Model allows communities to diagnose, then address their unique needs through appropriate technical assistance, training and resources. The APPEAL Model benefits both communities and funders through its ability to better understand their readiness to conduct tobacco control and have realistic expectations on the outcomes of those efforts.

CONCLUSIONS

This paper describes the elements of the Readiness model for AAPIS, particularly those addressing research and data issues, current applications of the model in specific AAPI ethnic communities, and the lessons learned thus far regarding the model's applicability to, and support of, the development of AAPI tobacco control efforts nationally.

Trapped-particle asymmetry modes in single-species plasmas

Novel trapped-particle asymmetry modes propagate on cylindrical electron columns when axial variations in the wall voltage cause particle trapping. These modes consist of E x B drifts of edge-trapped particles, partially shielded by axial flows of interior untrapped particles. A simple model agrees well with the observed frequencies and eigenfunctions, but the strong mode damping is as yet unexplained. These modes may be important in coupling trap asymmetries to particle motions and low frequency E x B drift modes.

YUA001, a novel aldose reductase inhibitor isolated from alkalophilic Corynebacterium sp. YUA25. II. Chemical modification and biological activity

A series of novel N-substituted tyramine (2-p-hydroxyphenylethylamine) derivatives (1 to approximately 11) were synthesized and evaluated for their inhibitory activity against pig kidney aldose reductase (EC 1, 1, 1, 21). Of these compounds, N-2-p-hydroxyphenylethyl maleamic acid (10) exhibits the strongest aldose reductase inhibitory activity, which is 22 times more potent than that of YUA001.

The nsdD gene encodes a putative GATA-type transcription factor necessary for sexual development of Aspergillus nidulans

The ability to reproduce both sexually and asexually is one of the characteristics of the homothalic ascomycete Aspergillus nidulans. Unlike the other Aspergillus species, A. nidulans undergoes sexual development that seems to be regulated by internal and external stimuli. To begin to understand the sexual reproduction of A. nidulans we previously isolated and characterized several NSD (never in sexual development) mutants that failed to produce any sexual reproductive organs, and identified four complementation groups, nsdA, nsdB, nsdC, and nsdD. The nsdD gene has been isolated, and it is predicted to encode a GATA-type transcription factor with the type IVb zinc finger DNA-binding domain. The mRNA of the nsdD gene started to accumulate in the early phase of vegetative growth, and the level increased as sexual development proceeded. However, it decreased during asexual sporulation and no nsdD mRNA was detected in conidia. Deletion of nsdD resulted in no cleistothecia (fruiting bodies) formation, even under the conditions that preferentially promoted sexual development, indicating that nsdD is necessary for sexual development. In contrast, when the nsdD gene was over-expressed, sexual-specific organ (Hülle cell) was formed even in submerged culture, which normally completely blocked sexual development, and the number of cleistothecia was also dramatically increased on solid medium. These results lead us to propose that the nsdD gene functions in activating sexual development of A. nidulans. Multiple copies of the nsdD gene could suppress nsdB5 and veA1, indicating that either nsdD acts downstream of these genes or possibly functions in overlapping pathway(s).

Rb-associated protein 46 (RbAp46) inhibits transcriptional transactivation mediated by BRCA1

The retinoblastoma suppressor (Rb)-associated protein 46 (RbAp46) is a member of the WD-repeat protein family and a component of the histone modifying and remodeling complexes. Previously, we demonstrated that RbAp46 is a potent growth inhibitor that can suppress the transformed phenotype of tumor cells. To explore the molecular mechanisms of RbAp46 function, we used RbAp46 as a bait in a yeast two-hybrid screening and found that RbAp46 interacts specifically with the C-terminal region of BRCA1 (the BRCT domain), a domain involved in the t transactivation activity of BRCA1. Coimmunoprecipitation assays demonstrated that the interaction of RbAp46 with BRCA1 requires the first two of the four Trp-Asp (WD)-repeats of RbAp46. We also showed that expression of RbAp46 represses the transactivation activity mediated by the BRCT/Gal4 fusion protein and inhibits the transactivation of the p21 promoter mediated by the full-length BRCA1. Interestingly, the association of BRCA1 and RbAp46 is disrupted in cells treated with DNA-damaging agents. These results suggest that RbAp46 may specifically interact with BRCA1 and modulate its transactivation activity in response to DNA damage.