In vitro zygotic embryo culture of wild Musa acuminata ssp.malaccensis and factors affecting germination and seedling growth

In vitro zygotic embryo culture of wild banana significantly increased the germination compared to greenhouse grown seeds. Embryo orientation and BAP concentration significantly affected germination rate. These factors together with gelling agent, dark and light conditions and coconut water, also showed variable effects on the number of roots per plant, root length, shoot length, number of days to root emergence and number of days to shoot emergence.     

Dissecting the cofactor-dependent and independent bindings of PDE4 inhibitors

Type 4 phosphodiesterases (PDE4s) are metallohydrolases that catalyze the hydrolysis of cAMP to AMP. At the bottom of its active site lie two divalent metal ions in a binuclear motif which are involved in both cAMP binding and catalysis [(2000) Science 288, 1822-1825; (2000) Biochemistry 39, 6449-6458]. Using a SPA-based equilibrium [(3)H]rolipram binding assay, we have determined that Mg(2+), Mn(2+), and Co(2+) all mediated a high-affinity (K(d) between 3 and 8 nM) and near stoichiometric (R)-rolipram binding to PDE4. In their absence, (R)-rolipram binds stoichiometrically to the metal ion-free apoenzyme with a K(d) of approximately 150 nM. The divalent cation dose responses in mediating the high-affinity rolipram/PDE4 interaction mirror their efficacy in catalysis, suggesting that both metal ions of the holoenzyme are involved in mediating the high-affinity (R)-rolipram/PDE4 interaction. The specific rolipram binding to the apo- and holoenzyme is differentially displaced by cAMP, AMP, and other inhibitors, providing a robust tool to dissect the components of metal ion-dependent and independent PDE4/ligand interactions. cAMP binds to the holoenzyme with a K(s) of 1.9 microM and nonproductively to the apoenzyme with a K(d) of 179 microM. In comparison, AMP binds to the holo- and apoenzyme with K(d) values of 7 and 11 mM, respectively. The diminished Mg(2+)-dependent component of AMP binding to PDE4 suggests that most of the Mg(2+)/phosphate interaction in the cAMP/PDE4 complex is disrupted upon the hydrolysis of the cyclic phosphoester bond, leading to the rapid release of AMP.     

Further phenotypic delineation of subtelomeric (terminal) 4q deletion with emphasis on intracranial and reproductive anatomy

Hypoplastic left heart syndrome(HLHS) refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the left ventricular outflow tract. In addition, the syndrome includes underdevelopment of the left ventricle, aorta, and aortic arch, as well as mitral atresia or stenosis. HLHS has been reported to occur in approximately 0.016 to 0.036% of all live births. Newborn infants with the condition generally are born at full term and initially appear healthy. As the arterial duct closes, the systemic perfusion becomes decreased, resulting in hypoxemia, acidosis, and shock. Usually, no heart murmur, or a non-specific heart murmur, may be detected. The second heart sound is loud and single because of aortic atresia. Often the liver is enlarged secondary to congestive heart failure. The embryologic cause of the disease, as in the case of most congenital cardiac defects, is not fully known. The most useful diagnostic modality is the echocardiogram. The syndrome can be diagnosed by fetal echocardiography between 18 and 22 weeks of gestation. Differential diagnosis includes other left-sided obstructive lesions where the systemic circulation is dependent on ductal flow (critical aortic stenosis, coarctation of the aorta, interrupted aortic arch). Children with the syndrome require surgery as neonates, as they have duct-dependent systemic circulation. Currently, there are two major modalities, primary cardiac transplantation or a series of staged functionally univentricular palliations. The treatment chosen is dependent on the preference of the institution, its experience, and also preference. Although survival following initial surgical intervention has improved significantly over the last 20 years, significant mortality and morbidity are present for both surgical strategies. As a result pediatric cardiologists continue to be challenged by discussions with families regarding initial decision relative to treatment, and long-term prognosis as information on long-term survival and quality of life for those born with the syndrome is limited.     

Hip joint replacement surgery for idiopathic osteoarthritis aggregates in families

In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA), we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with hip OA than in those with knee OA.     

Catalytic inactivation of protein tyrosine phosphatase CD45 and protein tyrosine phosphatase 1B by polyaromatic quinones

Polyaromatic quinones, such as the environmental pollutants 9,10-phenanthrenediones, elicit a wide range of responses including growth inhibition, immune suppression, and glucose normalization in diabetic models. Yet the molecular mechanisms behind these effects remain controversial. Here we report that many of them are oxygen-dependent and catalytic inactivators of protein tyrosine phosphatases (PTP). Under aerobic conditions, the PTP inactivation by 2-nitro-9,10-phenanthrenedione followed a pseudo-first-order process, with the rate of inactivation increasing nearly linearly with increasing inhibitor concentration, yielding apparent inactivation rate constants of 4300, 387, and 5200 M(-1) s(-1) at pH 7.2 against CD45, PTP1B, and LAR, respectively. The rate of CD45 inactivation increased approximately 25-fold from pH 6.0 to 7.5, with complete inactivation achieved using a catalytic amount (0.05 molar equiv) of the inhibitor. The quinone-catalyzed CD45 inactivation was prevented by catalase or superoxide dismutase. Inactivated CD45 after (125)I-9,10-phenanthrenedione treatment carried no radioactivity, indicating the absence of a stable inhibitor/enzyme complex. The activity of inactivated CD45 was partially restored ( approximately 10%) by hydroxylamine or dithiothreitol, supporting the presence of a small population of sulfenic acid or sulfenyl-amide species. Treatment of PTP1B with 2-nitro-9,10-phenanthrenedione resulted in the specific and sequential oxidation of the catalytic cysteine to the sulfinic and sulfonic acid. These results suggest that reactive oxygen species and the semiquinone radical, continuously generated during quinone-catalyzed redox cycling, mediate the specific catalytic cysteine oxidation. Naturally occurring quinones may act as efficient regulators of protein tyrosine phosphorylation in biological systems. Aberrant phosphotyrosine homeostasis resulting from continued polyaromatic hydrocarbon quinone exposure may play a significant role in their disease etiology.     

饲喂黄曲霉毒素B_1大鼠肝中AFB_1-DNA加合物的免疫组织化学研究

应用免疫组织化学ＳＰ法对４例饲喂黄曲霉毒素Ｂ１的Ｗｉｓｔａｒ大鼠肝组织中ＡＦＢ１－ＤＮＡ加合物的染色及常规ＨＥ染色发现,４例肝细胞核均出现异型性,但未见肝细胞坏死、增生灶及肝细胞癌;免疫组化揭示部分肝细胞核出现棕黄色、不均质状的ＡＦＢ１－ＤＮＡ加合物,阳性细胞数占１０～８５％。结果提示免疫组织化学方法可作为一种ＡＦＢ１的定位方法,ＡＦＢ１在动物致癌过程中ＡＦＢ１－ＤＮＡ加合物可能具有启动作用     

Encounter with New Resources Causes Polarized Growth of the Cord-Forming Basidiomycete Phanerochaete velutina on Soil

Abstract The development and physiology of cord-forming saprotrophic basidiomycetes, which form extensive and persistent mycelial networks in woodland ecosystems, can be conveniently studied on non-sterile soil in laboratory microcosms mimicking field conditions. Morphological responses of Phanerochaete velutina mycelial systems to resource encounters, and decay partitioning following encounters, varied according to whether simulated woody litter was unsterile or autoclaved and on whether encounter took place at the mycelial foraging front or behind the margin (simulating litter fall onto established systems in the field). Results show that encounter of discrete resources by P. velutina is rapidly communicated to the entire mycelial system; that resource capture takes high priority at the expense of continued system extension and decay-derived carbon reallocation; and that polarized growth toward newly encountered resources, previously considered to occur infrequently with this species, may be readily detected using image analysis techniques. Potential advantages of polarized development of P. velutina are discussed.     

Antibody to mouse alpha/beta interferon abrogates Pichinde virus-induced liver lesions in suckling mice.

Infection of newborn C3HeB/FeJ mice with the arenavirus Pichinde resulted in stunted growth, severe liver cell degeneration, and death. Administration of sheep anti-mouse alpha/beta interferon globulin completely abrogated liver lesions in virus-infected mice, although it did not decrease the incidence of mortality. These results indicate that endogenous interferon may be responsible for some manifestations of viral disease.