bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphological and physiological analysis of cleistogamy in barley (Hordeum vulgare)
Authors: Honda Ichiro , Turuspekov Yerlan , Komatsuda Takao , Watanabe Yoshiaki
Published: July 2005

We previously reported that cleistogamy/chasmogamy (CL/CH) of barley (Hordeum vulgare L.) is controlled by either two tightly linked genes or one gene with multiple alleles. To clarify the morphological and physiological mechanisms of barley CL, we analysed the lodicule size and auxin response of two cultivars whose CL/CH was controlled by two different genes, cly1 and Cly2. In both cases, lodicules of the CL parent were smaller than those of the CH parent. Analyses of lodicule size and flowering phenotype of f1 plants and segregation analyses of the mapping population indicated that lodicule size co‐segregated with the flowering phenotype. Indole‐3‐acetic acid (IAA) and other synthetic auxins, such as 2,4‐dichlorophenoxyacetic acid, induced abnormal flowering in CH ears, in which florets remained open for a few days instead of the normal hour or so, but not in CL ears. This auxin effect also co‐segregated with the flowering phenotype. Analyses of auxin‐related compounds in the floret organs revealed that the anther contained high levels of IAA, whereas indole‐3‐carboxylic acid, a putative decarboxylated metabolite of IAA, accumulated only in lodicules of CH plants just at flowering. These results indicate that lodicule size and auxin response are pleiotropic effects of the CL gene, which may play a role in auxin response or metabolism.
Chilling tolerance of cucumber (Cucumis sativus) seedling radicles is affected by radicle length, seedling vigor, and induced osmotic‐ and heat‐shock proteins
Authors: Kang Ho‐Min , Park Kuen‐Woo , Saltveit Mikal E.
Published: July 2005

Cucumber seedling radicles decrease in chilling tolerance as they increase in length or decrease in vigor. The protein content of the apical 5 mm of the radicle decreased with decreases in chilling tolerance (R2 = 0.92). This general reduction in protein content was reflected in a decrease of six dehydrin‐like proteins with apparent molecular weights of 13.0, 15.0, 16.8, 23.0, 26.8, and 33.5 kDa. The disappearance of naturally occurring dehydrin‐like proteins in cucumber seedling radicles as they elongate or lose vigor was correlated with a loss of chilling tolerance. Exposure to an osmotic (0.6 M mannitol) or heat (2 min at 45°C) stress enhanced chilling tolerance. The osmotic‐shock treatment induced both chilling tolerance and the appearance or strengthening of dehydrin‐like proteins previously present in radicles. The heat‐shock treatment also induced high levels of chilling tolerance and protein(s) that reacted with a 23 and 70 kDa antibody. However, these heat‐shock protein (HSPs) did not cross react with the probe for dehydrin‐like proteins. When organized into high, medium, and low chilling tolerance groups, radicle that were chilling tolerant contained either the 13.0 and 16.8 kDa dehydrin‐like proteins, or the 15.0 and 23.0 kDa dehydrin‐like proteins, or the 23 or 70 kDa HSP.
Suicidal ideation and associated factors among community‐dwelling elders in Taiwan
Authors: YEN YUNG‐CHIEH , YANG MING‐JEN , YANG MEI‐SANG , LUNG FOR‐WEY , SHIH CHUN‐HUA , HAHN CHENG‐YI , LO HSIN‐YI
Published: July 2005

Abstract  The purpose of the present study was to explore the suicidal ideation of community‐dwelling elderly and the factors associated with their intention to commit suicide. Using a multilevel stratified sampling strategy, 1000 elderly subjects were recruited (aged 65–74 years old) in Taiwan during the year 2001. The degree of depression and its correlates were assessed. Suicidal ideation was measured by asking respondents if they had had any suicidal thoughts in the previous week. In all, 16.7% of respondents reported suicidal ideation within the past week; its occurrence was related to sex, religious belief, employment status, marital status, average family monthly income, physical health status, depressive symptoms, and community activity participation. Further multivariate logistic regression revealed that, aside from depressive symptoms and a lower level of education, no community participation in the past 6 months was significantly associated with the appearance of suicidal ideation. The prevalence of suicidal ideation among the elderly in Taiwan is higher than in Western countries. Participation in social activities is negatively associated with elderly suicidal ideation. The dimension of social participation deserves further exploration and should be considered in community mental health promotion interventions for elderly people.
Influence of depression and HIV serostatus on the neuropsychological performance of injecting drug users
Authors: WALDROP‐VALVERDE DRENNA , OWNBY RAYMOND L. , KUMAR MAHENDRA
Published: July 2005

Abstract  Depression is common in injecting drug users (IDUs), a group at significant risk for HIV infection. Moreover, both HIV infection and depression have been shown to adversely effect neurocognitive abilities. Understanding the effects of depression and HIV infection on the neurocognitive functioning of drug users is essential for appropriate management and/or treatment of these deficits in this population. Therefore, the purpose of the present study was to investigate the effects of depression and HIV status on cognitive functioning in 100 male and female IDUs. Participants were categorized into three groups of depression severity based on their scores on the Beck Depression Inventory: no depression, mild depression, and moderate to severe depression. The effects of depression and HIV serostatus as well as their interaction were assessed. Results indicated that regardless of serostatus, those with moderate to severe depression had lower scores on cognitive measures. These findings suggest that although depression contributes to poor neuropsychological performance in IDUs, this effect was not exacerbated by HIV infection. The finding also illustrates the importance of addressing depression‐related neurocognitive deficits in IDUs.
Twelve‐month prevalence, severity, and treatment of common mental disorders in communities in Japan: preliminary finding from the World Mental Health Japan Survey 2002–2003
Authors: KAWAKAMI NORITO , TAKESHIMA TADASHI , ONO YUTAKA , UDA HIDENORI , HATA YUKIHIRO , NAKANE YOSHIBUMI , NAKANE HIDEYUKI , IWATA NOBORU , FURUKAWA TOSHIAKI A. , KIKKAWA TAKEHIKO
Published: July 2005

Abstract To estimate the prevalence, severity, and treatment ofDiagnostic and Statistical Manual of Mental Disorders(4th edn; DSM‐IV) mental disorders in community populations in Japan, face‐to‐face household surveys were conducted in four community populations in Japan. A total of 1663 community adults responded (overall response rate, 56%). The DSM‐IV disorders, severity, and treatment were assessed with the World Mental Health version of the World Health Organization (WHO) Composite International Diagnostic Interview (WMH‐CIDI), a fully structured lay‐administered psychiatric diagnostic interview. The prevalence of any WMH‐CIDI/DSM‐IV disorder in the prior year was 8.8%, of which 17% of cases were severe and 47% were moderate. Among specific disorders, major depression (2.9%), specific phobia (2.7%), and alcohol abuse/dependence (2.0%) were the most prevalent. Although disorder severity was correlated with probability of treatment, only 19% of the serious or moderate cases received medical treatment in the 12 months before the interview. Older and not currently married individuals had a greater risk of having more severe DSM‐IV disorders if they had experienced any within the previous 12 months. Those who had completed high school or some college were more likely to seek medical treatment than those who had completed college. The study confirmed that the prevalence of DSM‐IV mental disorders was equal to that observed in Asian countries but lower than that in Western countries. The percentage of those receiving medical treatment was low even for those who suffered severe or moderate disorders. Possible strategies are discussed.
Prevalence of restless legs syndrome in non‐institutionalized Japanese elderly
Authors: MIZUNO SOICHI , MIYAOKA TSUYOSHI , INAGAKI TAKUZI , HORIGUCHI JUN
Published: July 2005

Abstract  The purpose of the present paper was to evaluate the prevalence of restless legs syndrome (RLS) in a non‐institutionalized Japanese elderly population. The subjects consisted of 8900 elderly people >65 years of age belonging to the Seniors Association in Izumo City in November 2000. The present study was conducted in two parts. The phase 1 investigation was a screening by mailed questionnaire and the phase 2 investigation was diagnosis by face‐to‐face interview. Subjects with possible cases of RLS in phase 1 proceeded to phase 2 and definite cases of RLS were then detected. In phase 1, a total of 3287 subjects completely answering all questionnaire items, were defined as the subjects of the present study. A total of 150 were classified as having ‘probable RLS’, resulting in a prevalence of 4.6%. These subjects with probable RLS in phase 1 were detected as the subjects of phase 2. By face‐to‐face interview and various clinical examinations, a total of 35 subjects (nine male, 26 female) were diagnosed as having definite RLS, resulting in a prevalence of 1.06%. Furthermore, seven subjects (two male, five female) with symptomatic RLS were detected and finally 28 subjects (seven male, 21 female) were diagnosed as having idiopathic RLS. It was significantly higher in women for both the total and idiopathic RLS groups (0.60% male vs 1.46% female; 0.46% male vs. 1.18% female, respectively). The prevalence of RLS may be lower in the Japanese elderly than that in Caucasian subjects. These results could enhance understanding of the differences in predisposition between the races.
Depression and associated factors of informal caregivers versus professional caregivers of demented patients
Authors: TAKAHASHI MEGUMI , TANAKA KATSUTOSHI , MIYAOKA HITOSHI
Published: July 2005

Abstract  To examine the differences in depressive state and associated factors between informal and professional caregivers, a cross‐sectional study was carried out in 23 informal home‐based caregivers of demented patients, 24 professional caregivers working in the dementia ward of a psychiatric hospital, and 31 controls. Measurements included severity of dementia (Clinical Dementia Rating Scale, Mini Mental State Examination, MMSE) and levels of caregivers depression (Beck Depression Inventory; BDI), care burden (Zarit Caregiver Burden Interview; ZBI) and quality of life (World Health Organization–Quality of Life‐26, WHO‐QOL26). Informal caregivers had the highest BDI score and ZBI and the lowest QOL among the three studied groups. Regarding informal caregivers, there was a strong positive correlation between BDI and ZBI scores. The BDI and ZBI scores were significantly high when patients exhibited behavioral problems. The four WHO‐QOL categories (physical domain, psychological domain, social relationships and environment) had a strong negative correlation with BDI. Regression analysis demonstrated that the psychological domain points of WHO‐QOL, role strain factor of ZBI and MMSE score were significantly associated with BDI. Regarding professional caregivers, their BDI score had a strong negative correlation with the physical and psychological domains and environment categories of WHO‐QOL. Regression analysis demonstrated that their BDI score was significantly associated with the psychological domain and environment. It is thus very important to provide sufficient social care services and/or personal support to informal caregivers.
Continuation electroconvulsive therapy for relapse prevention in middle‐aged and elderly patients with intractable catatonic schizophrenia
Authors: SUZUKI KAZUMASA , AWATA SHUICHI , TAKANO TAKEHISA , EBINA YUKIO , IWASAKI HITOSHI , MATSUOKA HIROO
Published: July 2005

Abstract  The authors have previously studied the short‐term effect of the first acute electroconvulsive therapy (ECT) course (phase 1 study) on intractable catatonic schizophrenia and the 1‐year relapse rate after response to the acute ECT (phase 2 study) in middle‐aged and elderly patients. Results indicated that, although acute ECT has an excellent short‐term effect, the 1‐year relapse rate after response to acute ECT is high despite the use of continuation neuroleptics. In the present prospective study the effect was explored of continuation ECT with neuroleptics on the prevention of relapse after response to a second acute ECT course in the relapsed participants of the phase 2 study. The present study included seven consecutive patients >45 years of age with catatonic schizophrenia (Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM‐IV) who relapsed (despite the use of neuroleptics) within 1 year after response to the first acute ECT course, and then responded to the second acute ECT course. The patients were given continuation ECT combined with neuroleptics; four ECT sessions at weekly intervals, then four ECT sessions every 2 weeks, then three ECT sessions every 4 weeks. Clinical symptoms were evaluated by means of the Brief Psychiatric Rating Scale (BPRS) weekly for 48 weeks or until relapse. Relapse was defined as a BPRS score of at least 37 for 3 consecutive days. Three out of the seven patients (42.9%) had a sustained response to ECT during the 1‐year follow‐up period. In the seven patients the probability of relapse within 1 year under treatment with neuroleptics alone (phase 2 study) was statistically higher than that under continuation ECT combined with neuroleptics (present study). No statistical differences were seen between the phase 2 study and the present study in the severity of psychiatric symptoms, global social function, the number of acute ECT sessions or the dosage of neuroleptics. No patient experienced a severe cognitive or physical adverse effect resulting from continuation ECT. Continuation ECT with neuroleptics is an efficacious and safe treatment for maintaining a response in middle‐aged and elderly patients with intractable catatonic schizophrenia who have relapsed after a positive response to acute ECT despite the use of continuation neuroleptics.
CYP2D6 gene deletion allele in patients with neuroleptic malignant syndrome: Preliminary report
Authors: KATO DAIJI , KAWANISHI CHIAKI , KISHIDA IKUKO , FURUNO TAKU , MATSUMURA TAKEHIKO , HASEGAWA HANA , SUZUKI KYOKO , HIRAYASU YOSHIO
Published: July 2005

Abstract  Neuroleptic malignant syndrome (NMS) is a potentially fatal adverse reaction to psychopharmacologic treatment. Reported herein are two NMS patients with schizophrenia who were found to possess a CYP2D6 gene deletion allele (CYP2D6*5). The deletion results in decreased CYP2D6 activity, possibly leading to drug accumulation. Both patients with NMS had been treated with neuroleptics, including CYP2D6 substrates. Polymerase chain reaction (PCR) followed by restriction fragment length polymorphism analyses and long PCR were performed to detect CYP2D6 genotype. One patient was found to possess *5/*10; the other had a *1/*5 genotype. The present preliminary report suggests that pharmacokinetic factors cannot be excluded and the CYP2D6 polymorphism is possibly associated with the etiology of NMS.
Dumping in a Linder Model of Trade with Multiple Retail Channels
Authors: Chung Ling Wei , Hartigan James C.
Published: July 2005

The last decade has witnessed an accelerating adoption of AD laws by LDCs and their increasing usage against developed countries. Our model of third degree price discrimination with heterogenous consumers that have differing preferences for quality in the two countries suggests that this is likely to continue. Duopolistic interaction may yield bilateral dumping, or unilateral dumping in either direction, under free trade. Even when dumping is unidirectional, there is a compelling basis for the introduction of AD laws by both governments. This mitigates competition, which is beneficial for both firms, and portends pessimism for an abatement of this recent proliferation of AD laws and complaints.
On the Equivalence of Tariffs and Quotas under a Revenue Constraint
Authors: Chiou Jiunn‐Rong , Hwang Hong , Lin Yan‐Shu
Published: July 2005

This paper sets out a duopolistic model to examine the price and welfare equivalence of tariffs and quotas, given the quota rent is equal to the tariff revenue. It shows that the domestic welfare ranking of the two trade policies crucially depends on the relative costs of the domestic and foreign firms; when the domestic firm's relative costs are lower than those of the foreign firm, a quota regime generally leads to a higher welfare level than that of an equivalent tariff regime. This finding contrasts sharply with the conclusions of Dasgupta and Stiglitz (1977), where it was found that a tariff regime always generates higher domestic welfare.
Income Inequality and Macroeconomic Volatility: An Empirical Investigation
Authors: Breen Richard , García‐Peñalosa Cecilia
Published: July 2005

We explore the impact of macroeconomic volatility on the distribution of income. Using a cross‐section of developed and developing countries, we find that greater output volatility, defined as the standard deviation of the rate of output growth, is associated with a higher Gini coefficient and income share of the top quintile. The coefficients suggest that a strong effect on inequality resulting from a reduction in volatility: the Gini coefficient of a country like Chile would fall by 6 points if it were to reduce its volatility to the same level as Sweden or Norway. Our results seem not to be driven by the high‐inequality/high‐volatility Latin American countries.
Caste, Inequality, and Poverty in India
Authors: Borooah Vani K.
Published: July 2005

This paper analyses inequality and poverty in India within the context of caste‐based discrimination. It does so by decomposing the difference between (caste) Hindu and Scheduled Caste (SC) and Scheduled Tribe (ST) households in: their average household incomes; their probabilities of being in different income percentiles; their probabilities of being at different levels of poverty into: a “discrimination effect”, which stems from the fact that a household's income level, into which its (income‐generating) profile translates, depends on whether it is SC/ST; an “attributes (or residual) effect” which stems from the fact that there are systematic differences between SC/ST and Hindu households in their (income‐generating) profiles. The results, based on unit record data for 28,922 households, showed that at least one‐third of the average income/probability differences between Hindu and SC/ST households was due to the “unequal treatment” of the latter.
The Persistence of Income Shocks: Evidence from Rural Indonesia
Authors: Newhouse David
Published: July 2005

This paper estimates the persistence of transient income shocks to farm households in rural Indonesia. Persistence is defined as the elasticity of a household's 1997 household per capita income with respect to its 1993 per capita income, controlling for time‐invariant characteristics of the household. Local rainfall levels are used as an exogenous source of transitory variation in 1993 income. Four main conclusions emerge. First, roughly 30% of household income shocks remain after four years. Second, the persistence of negative and positive shocks is approximately equal; if anything, positive shocks last longer. Third, neither positive nor negative income shocks disproportionately affect poor households. Finally, measurement error in income and unobserved household heterogeneity are important sources of bias. These findings cast doubt on common arguments advocating public intervention to stabilize or redistribute income, and suggest that anti‐poverty policy should address more permanent causes of household poverty.
Long-Lasting Cephalic Jabs (?) The Vågå Study of Headache Epidemiology
Authors: Sjaastad O , Pettersen H , Bakketeig LS
Published: July 2005

Jabs (stabs) usually last ≤3 s and are located in the skull area, mostly anteriorly. In many cases, there are only a few jabs during lifetime. With this definition, jabs are frequent, thus at 35.2% in the Vågå study of headache epidemiology. Long-lasting jabs (?), i.e. paroxysms lasting 10-120 s, were present in six out of 1779 parishioners. These pain paroxysms seemed mainly to be side-locked, but could not be provoked. Possibly, these long-lasting jabs after all mainly are regular jabs. To include the ≤2-minute-long paroxysms among the jabs will necessitate a rather drastic change of criteria. This group of jabs may, nevertheless, be heterogeneous. In two parishioners, the paroxysms were associated with a migraine-like pain. The paroxysms occasionally became most intense (2-10 times the basal pain), and then, and only then, were they combined with stark, visual phenomena: wave-like movements ('undulation'), anopsia, but also: immense dizziness, nausea/vomiting. The nature of the side-locked basal pain, although migraine-like, remains unsolved.
Gene expression profiling of cultured human NF1 heterozygous (NF1+/–) melanocytes reveals downregulation of a transcriptional cis‐regulatory network mediating activation of the melanocyte‐specific dopachrome tautomerase (DCT) gene
Authors: Boucneau Joachim , De Schepper Sofie , Vuylsteke Marnik , Van Hummelen Paul , Naeyaert Jean‐Marie , Lambert Jo
Published: July 2005

One of the major primary features of the neurocutaneous genetic disorder Neurofibromatosis type 1 are the hyperpigmentary café‐au‐lait macules where disregulation of melanocyte biology is supposed to play a key etiopathogenic role. To gain better insight into the possible role of the tumor suppressor gene NF1, a transcriptomic microarray analysis was performed on human NF1 heterozygous (NF1+/–) melanocytes of a Neurofibromatosis type 1 patient and NF1 wild type (NF1+/+) melanocytes of a healthy control patient, both cultured from normally pigmented skin and hyperpigmented lesional café‐au‐lait skin. From the magnitude of gene effects, we found that gene expression was affected most strongly by genotype and less so by lesional type. A total of 137 genes had a significant twofold or more up‐ (72) or downregulated (65) expression in NF1+/– melanocytes compared with NF1+/+ melanocytes. Melanocytes cultured from hyperpigmented café‐au‐lait skin showed 37 upregulated genes whereas only 14 were downregulated compared with normal skin melanocytes. In addition, significant genotype ×lesional type interactions were observed for 465 genes. Differentially expressed genes were mainly involved in regulating cell proliferation and cell adhesion. A high number of transcription factor genes, among which a specific subset important in melanocyte lineage development, were downregulated in the cis‐regulatory network governing the activation of the melanocyte‐specific dopachrome tautomerase (DCT) gene. Although the results presented have been obtained with a restricted number of patients (one NF1 patient and one control) and using cDNA microarrays that may limit their interpretation, the data nevertheless addresses for the first time the effect of a heterozygous NF1 gene on the expression of the human melanocyte transcriptome and has generated several interesting candidate genes helpful in elucidating the etiopathology of café‐au‐lait macules in NF1 patients.
The ocular albinism type 1 (OA1) protein and the evidence for an intracellular signal transduction system involved in melanosome biogenesis
Authors: Schiaffino M. Vittoria , Tacchetti Carlo
Published: July 2005

Ocular albinism type 1 is an X‐linked disorder characterized by severe reduction of visual acuity, retinal hypopigmentation, foveal hypoplasia, optic misrouting and the presence of giant melanosomes (macromelanosomes) in skin melanocytes and retinal pigment epithelium. The protein product of the OA1 gene is a pigment cell specific membrane glycoprotein, displaying structural and functional features of G protein‐coupled receptors (GPCRs). However, in contrast to all other previously characterized GPCRs, OA1 is not localized to the plasma membrane, but is targeted to intracellular organelles, namely late endosomes/lysosomes and melanosomes. These unique characteristics suggest that OA1 represents the first example described so far of an exclusively intracellular GPCR and regulates melanosome biogenesis by transducing signals from the organelle lumen to the cytosol. These findings support previous hypotheses that GPCR‐mediated signaling might also operate at the internal membranes in mammalian cells.
Early disease onset and increased risk of other autoimmune diseases in familial generalized vitiligo
Authors: Laberge Greggory , Mailloux Christina M. , Gowan Katherine , Holland Paulene , Bennett Dorothy C. , Fain Pamela R. , Spritz Richard A.
Published: July 2005

Generalized vitiligo is an autoimmune disorder in which acquired white patches of skin and overlying hair result from autoimmune loss of melanocytes from involved areas. Although usually sporadic, family clustering of vitiligo may occur, in a non‐Mendelian pattern typical of multifactorial, polygenic inheritance. Sporadic vitiligo is associated with autoimmune thyroid disease, pernicious anemia, Addison's disease, and lupus; these same disorders occur at increased frequency in patients’ first‐degree relatives. Here, we studied 133 ‘multiplex’ generalized vitiligo families, with multiple affected family members. The age of onset of vitiligo is earlier in these ‘multiplex’ families than in patients with sporadic vitiligo. Affected members of the multiplex vitiligo families have elevated frequencies of autoimmune thyroid disease, rheumatoid arthritis, psoriasis, adult‐onset insulin‐dependent diabetes mellitus, pernicious anemia, and Addison's disease. Probands’ unaffected siblings have elevated frequencies of most of these same autoimmune diseases, particularly if the proband had non‐vitiligo autoimmune disease. Familial generalized vitiligo is thus characterized by earlier disease onset and a broader repertoire of associated autoimmune diseases than sporadic vitiligo. This mostly likely reflects a greater inherited genetic component of autoimmune susceptibility in these families. These findings have important implications for autoimmune disease surveillance in families in which multiple members are affected with vitiligo.
Melanocytes in conditional Rb–/– mice are normal in vivo but exhibit proliferation and pigmentation defects in vitro
Authors: Tonks Ian D. , Hacker Elke , Irwin Nicole , Muller H. Konrad , Keith Patricia , Mould Arne , Zournazi Anna , Pavey Sandra , Hayward Nicholas K. , Walker Graeme , Kay Graham F.
Published: July 2005

The function of the retinoblastoma tumour suppressor (Rb1), and the pocket protein family in general, has been implicated as an important focal point for deregulation in many of the molecular pathways mutated in melanoma. We have focused on the role of Rb1 in mouse melanocyte homeostasis using gene targeting and Cre/loxP mediated tissue‐specific deletion. We show that constitutive Cre‐mediated ablation of Rb1 exon 2 prevents the production of Rb1 and recapitulates the phenotype encountered in other Rb1 knockout mouse models. Mice with conditional melanocyte‐specific ablation of Rb1 manifest overtly normal pigmentation and are bereft of melanocytic hyperproliferative defects or apoptosis‐induced depigmentation. Histologically, these mice have melanocyte morphology and distribution comparable with control littermates. In contrast, Rb1‐null melanocytes removed from their in vivo micro‐environment and cultured in vitro display some of the characteristics associated with a transformed phenotype. They proliferate at a heightened rate when compared with control melanocytes and have a decreased requirement for mitogens. With progressive culture the cells depigment at relatively early passage and display a gross morphology which, whilst reminiscent of early passage melanocytes, is generally different to equivalent passage control cells. These results indicate that Rb1 is dispensable for in vivo melanocyte homeostasis when its ablation is targeted from the melanoblast stage onwards, however, when cultured in vitro, Rb1 loss increases melanocyte growth but the cells are not fully transformed.
Diagnosis of ankylosis in permanent incisors by expert ratings, Periotest® and digital sound wave analysis
Authors: Campbell Karen M. , Casas Michael J. , Kenny David J. , Chau Tom
Published: July 2005

Abstract –  The objectives of this investigation were to: (i) assess the reliability of expert raters to detect ankylosis from recordings of percussion sounds, (ii) measure differences in Periotest® values (PTV) between ankylosed and non‐ankylosed incisors and (iii) identify characteristic differences in recorded percussion sounds from ankylosed and non‐ankylosed incisors using digital sound wave analysis. A convenience sample of healthy children (age range 7–18 years) was invited to participate. Ankylosis group children had one or more documented ankylosed maxillary incisors. Control group children had intact, non‐ankylosed incisors. Digital recordings of percussion sounds and PTV were acquired for each incisor of interest. Four experienced pediatric dentists rated the randomized percussion sound pairs for the presence of ankylosis. Percussion sounds were also subjected to digital sound wave analysis. Overall agreement for the expert raters was substantial (K = 0.7). Intra‐rater agreement was substantial to almost perfect (K = 0.6–0.9). Diagnosis of ankylosis demonstrated sensitivity of 76–92% and specificity of 74–100%. PTV from ankylosed incisors were statistically lower than PTV from non‐ankylosed incisors. Ankylosed incisor digital sound wave signals exhibited significantly more energy in high‐frequency bands than non‐ankylosed incisors. This investigation demonstrated that: (i) experienced pediatric dentists reliably detected ankylosis by percussion sound alone; (ii) PTV for ankylosed incisors were statistically lower than PTV from non‐ankylosed incisors; and (iii) ankylosed incisors exhibited a higher proportion of their signal energy in high‐frequency bands.
Retention of the duplicated cellular retinoic acid‐binding protein 1 genes (crabp1a and crabp1b) in the zebrafish genome by subfunctionalization of tissue‐specific expression
Authors: Liu Rong‐Zong , Sharma Mukesh K. , Sun Qian , Thisse Christine , Thisse Bernard , Denovan‐Wright Eileen M. , Wright Jonathan M.
Published: July 2005

The cellular retinoic acid‐binding protein type I (CRABPI) is encoded by a single gene in mammals. We have characterized two crabp1 genes in zebrafish, designated crabp1a and crabp1b. These two crabp1 genes share the same gene structure as the mammalian CRABP1 genes and encode proteins that show the highest amino acid sequence identity to mammalian CRABPIs. The zebrafish crabp1a and crabp1b were assigned to linkage groups 25 and 7, respectively. Both linkage groups show conserved syntenies to a segment of the human chromosome 15 harboring the CRABP1 locus. Phylogenetic analysis suggests that the zebrafish crabp1a and crabp1b are orthologs of the mammalian CRABP1 genes that likely arose from a teleost fish lineage‐specific genome duplication. Embryonic whole mount in situ hybridization detected zebrafish crabp1b transcripts in the posterior hindbrain and spinal cord from early stages of embryogenesis. crabp1a mRNA was detected in the forebrain and midbrain at later developmental stages. In adult zebrafish, crabp1a mRNA was localized to the optic tectum, whereas crabp1b mRNA was detected in several tissues by RT‐PCR but not by tissue section in situ hybridization. The differential and complementary expression patterns of the zebrafish crabp1a and crabp1b genes imply that subfunctionalization may be the mechanism for the retention of both crabp1 duplicated genes in the zebrafish genome.
A mitochondrial cytochrome b mutation causing severe respiratory chain enzyme deficiency in humans and yeast
Authors: Blakely Emma L. , Mitchell Anna L. , Fisher Nicholas , Meunier Brigitte , Nijtmans Leo G. , Schaefer Andrew M. , Jackson Margaret J. , Turnbull Douglass M. , Taylor Robert W.
Published: July 2005

Whereas the majority of disease‐related mitochondrial DNA mutations exhibit significant biochemical and clinical heterogeneity, mutations within the mitochondrially encoded human cytochrome b gene (MTCYB) are almost exclusively associated with isolated complex III deficiency in muscle and a clinical presentation involving exercise intolerance. Recent studies have shown that a small number of MTCYB mutations are associated with a combined enzyme complex defect involving both complexes I and III, on account of the fact that an absence of assembled complex III results in a dramatic loss of complex I, confirming a structural dependence between these two complexes. We present the biochemical and molecular genetic studies of a patient with both muscle and brain involvement and a severe reduction in the activities of both complexes I and III in skeletal muscle due to a novel mutation in the MTCYB gene that predicts the substitution (Arg318Pro) of a highly conserved amino acid. Consistent with the dramatic biochemical defect, Western blotting and BN‐PAGE experiments demonstrated loss of assembled complex I and III subunits. Biochemical studies of the equivalent amino‐acid substitution (Lys319Pro) in the yeast enzyme showed a loss of enzyme activity and decrease in the steady‐state level of bc1 complex in the mutant confirming pathogenicity.
Oxidative stress is involved in the permeabilization of the inner membrane of brain mitochondria exposed to hypoxia/reoxygenation and low micromolar Ca2+
Authors: Schild Lorenz , Reiser Georg
Published: July 2005

From in vivo models of stroke it is known that ischemia/reperfusion induces oxidative stress that is accompanied by deterioration of brain mitochondria. Previously, we reported that the increase in Ca2+ induces functional breakdown and morphological disintegration in brain mitochondria subjected to hypoxia/reoxygenation (H/R). Protection by ADP indicated the involvement of the mitochondrial permeability transition pore in the mechanism of membrane permeabilization. Until now it has been unclear how reactive oxygen species (ROS) contribute to this process. We now report that brain mitochondria which had been subjected to H/R in the presence of low micromolar Ca2+ display low state 3 respiration (20% of control), loss of cytochrome c, and reduced glutathione levels (75% of control). During reoxygenation, significant mitochondrial generation of hydrogen peroxide (H2O2) was detected. The addition of the membrane permeant superoxide anion scavenger TEMPOL (4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl) suppressed the production of H2O2 by brain mitochondria metabolizing glutamate plus malate by 80% under normoxic conditions. TEMPOL partially protected brain mitochondria exposed to H/R and low micromolar Ca2+ from decrease in state 3 respiration (from 25% of control to 60% of control with TEMPOL) and permeabilization of the inner membrane. Membrane permeabilization was obvious, because state 3 respiration could be stimulated by extramitochondrial NADH. Our data suggest that ROS and Ca2+ synergistically induce permeabilization of the inner membrane of brain mitochondria exposed to H/R. However, permeabilization can only partially be prevented by suppressing mitochondrial generation of ROS. We conclude that transient deprivation of oxygen and glucose during temporary ischemia coupled with elevation in cytosolic Ca2+ concentration triggers ROS generation and mitochondrial permeabilization, resulting in neural cell death.
Purification and properties of the glutathione S‐transferases from the anoxia‐tolerant turtle, Trachemys scripta elegans
Authors: Willmore William G. , Storey Kenneth B.
Published: July 2005

Glutathione S‐transferases (GSTs) play critical roles in detoxification, response to oxidative stress, regeneration of S‐thiolated proteins, and catalysis of reactions in nondetoxification metabolic pathways. Liver GSTs were purified from the anoxia‐tolerant turtle, Trachemys scripta elegans. Purification separated a homodimeric (subunit relative molecular mass =34 kDa) and a heterodimeric (subunit relative molecular mass = 32.6 and 36.8 kDa) form of GST. The enzymes were purified 23–69‐fold and 156–174‐fold for homodimeric and heterodimeric GSTs, respectively. Kinetic data gathered using a variety of substrates and inhibitors suggested that both homodimeric and heterodimeric GSTs were of the α class although they showed significant differences in substrate affinities and responses to inhibitors. For example, homodimeric GST showed activity with known α class substrates, cumene hydroperoxide and p‐nitrobenzylchloride, whereas heterodimeric GST showed no activity with cumene hydroperoxide. The specific activity of liver GSTs with chlorodinitrobenzene (CDNB) as the substrate was reduced by 2.6‐ and 8.7‐fold for homodimeric and heterodimeric GSTs isolated from liver of anoxic turtles as compared with aerobic controls, suggesting an anoxia‐responsive stable modification of the protein that may alter its function during natural anaerobiosis.
Catalytic residues Lys197 and Arg199 of Bacillus subtilis phosphoribosyl diphosphate synthase
Authors: Hove‐Jensen Bjarne , Bentsen Ann‐Kristin K. , Harlow Kenneth W.
Published: July 2005

Eleven of the codons specifying the amino acids of the flexible catalytic loop [KRRPRPNVAEVM(197–208)] of Bacillus subtilis phosphoribosyl diphosphate synthase have been changed individually to specify alanine. The resulting variant enzyme forms, as well as the wildtype enzyme, were produced in an Escherichia coli strain lacking endogenous phosphoribosyl diphosphate synthase activity and purified to near homogeneity. The B. subtilis phosphoribosyl diphosphate synthase mutant variants K197A and R199A were studied in detail. The physical properties of the two enzymes were similar to those of the wildtype enzyme. Kinetic characterization showed that the Vmax values of the K197A and R199A mutant enzymes were more than 30 000‐ and more than 24 000‐fold reduced, respectively, compared to the wildtype enzyme. The Km values for ATP and ribose 5‐phosphate of the two mutant enzymes were essentially unchanged. Vapp values of the remaining mutant enzymes were much less affected, ranging from 20 to 100% of the Vmax value of the wildtype enzyme. The data presented show that Lys197 and Arg199 are important in stabilization of the transition state.
Laccase‐catalyzed polymerization of tyrosine‐containing peptides
Authors: Mattinen Maija‐Liisa , Kruus Kristiina , Buchert Johanna , Nielsen Jacob H. , Andersen Henrik J. , Steffensen Charlotte L.
Published: July 2005

Laccase‐catalyzed polymerization of tyrosine and tyrosine‐containing peptides was studied in the presence and absence of ferulic acid (FA). Advanced spectroscopic methods such as MALDI‐TOF MS, EPR, FTIR microscopy and HPLC‐fluorescence, as well as more conventional analytical tools: oxygen consumption measurements and SDS/PAGE were used in the reaction mechanism studies. Laccase was found to oxidize tyrosine and tyrosine‐containing peptides, with consequent polymerization of the compounds. The covalent linkage connecting the compounds was found to be an ether bond. Only small amounts of dityrosine bonds were detected in the polymers. When FA was added to the reaction mixtures, it was found to be incorporated into the polymer structure. Thus, in addition to homopolymers, different heteropolymers containing two or four FA residues were formed in the reactions.
Inhibition of α‐synuclein fibrillization by dopamine analogs via reaction with the amino groups of α‐synuclein
Authors: Li Hong‐Tao , Lin Dong‐Hai , Luo Xiao‐Ying , Zhang Feng , Ji Li‐Na , Du Hai‐Ning , Song Guo‐Qiang , Hu Jun , Zhou Jia‐Wei , Hu Hong‐Yu
Published: July 2005

Fibrillization of α‐synuclein (α‐Syn) is closely associated with the formation of Lewy bodies in neurons and dopamine (DA) is a potent inhibitor for the process, which is implicated in the causative pathogenesis of Parkinson's disease (PD). To elucidate any molecular mechanism that may have biological relevance, we tested the inhibitory abilities of DA and several analogs including chemically synthetic and natural polyphenols in vitro. The MS and NMR characterizations strongly demonstrate that DA and its analogs inhibit α‐Syn fibrillization by a mechanism where the oxidation products (quinones) of DA analogs react with the amino groups of α‐Syn chain, generating α‐Syn–quinone adducts. It is likely that the amino groups of α‐Syn undergo nucleophilic attack on the quinone moiety of DA analogs to form imino bonds. The covalently cross‐linked α‐Syn adducts by DA are primarily large molecular mass oligomers, while those by catechol and p‐benzoquinone (or hydroquinone) are largely monomers or dimers. The DA quinoprotein retains the same cytotoxicity as the intact α‐Syn, suggesting that the oligomeric intermediates are the major elements that are toxic to the neuronal cells. This finding implies that the reaction of α‐Syn with DA is relevant to the selective dopaminergic loss in PD.
Characterization of sequence variations in human histone H1.2 and H1.4 subtypes
Authors: Sarg Bettina , Gréen Anna , Söderkvist Peter , Helliger Wilfried , Rundquist Ingemar , Lindner Herbert H.
Published: July 2005

In humans, eight types of histone H1 exist (H1.1–H1.5, H1°, H1t and H1oo), all consisting of a highly conserved globular domain and less conserved N‐ and C‐terminal tails. Although the precise functions of these isoforms are not yet understood, and H1 subtypes have been found to be dispensable for mammalian development, it is now clear that specific functions may be assigned to certain individual H1 subtypes. Moreover, microsequence variations within the isoforms, such as polymorphisms or mutations, may have biological significance because of the high degree of sequence conservation of these proteins. This study used a hydrophilic interaction liquid chromatographic method to detect sequence variants within the subtypes. Two deviations from wild‐type H1 sequences were found. In K562 erythroleukemic cells, alanine at position 17 in H1.2 was replaced by valine, and, in Raji B lymphoblastoid cells, lysine at position 173 in H1.4 was replaced by arginine. We confirmed these findings by DNA sequencing of the corresponding gene segments. In K562 cells, a homozygous GCC→GTC shift was found at codon 18, giving rise to H1.2 Ala17Val because the initial methionine is removed in H1 histones. Raji cells showed a heterozygous AAA→AGA codon change at position 174 in H1.4, corresponding to the Lys173Arg substitution. The allele frequency of these sequence variants in a normal Swedish population was found to be 6.8% for the H1.2 GCC→GTC shift, indicating that this is a relatively frequent polymorphism. The AAA→AGA codon change in H1.4 was detected only in Raji cells and was not present in a normal population or in six other cell lines derived from individuals suffering from Burkitt's lymphoma. The significance of these sequence variants is unclear, but increasing evidence indicates that minor sequence variations in linker histones may change their binding characteristics, influence chromatin remodeling, and specifically affect important cellular functions.
In vitro selection and characterization of a stable subdomain of phosphoribosylanthranilate isomerase
Authors: Patrick Wayne M. , Blackburn Jonathan M.
Published: July 2005

The (βα)8‐barrel is the most common enzyme fold and it is capable of catalyzing an enormous diversity of reactions. It follows that this scaffold should be an ideal starting point for engineering novel enzymes by directed evolution. However, experiments to date have utilized in vivo screens or selections and the compatibility of (βα)8‐barrels with in vitro selection methods remains largely untested. We have investigated plasmid display as a suitable in vitro format by engineering a variant of phosphoribosylanthranilate isomerase (PRAI) that carried the FLAG epitope in active‐site‐forming loop 6. Trial enrichments for binding of mAb M2 (a mAb to FLAG) demonstrated that FLAG‐PRAI could be identified from a 106‐fold excess of a FLAG‐negative competitor in three rounds of in vitro selection. These results suggest PRAI as a useful scaffold for epitope and peptide grafting experiments. Further, we constructed a FLAG‐PRAI loop library of ≈ 107 clones, in which the epitope residues most critical for binding mAb M2 were randomized. Four rounds of selection for antibody binding identified and enriched for a variant in which a single nucleotide insertion produced a truncated (βα)8‐barrel consisting of (βα)1−5β6. Biophysical characterization of this clone, trPRAI, demonstrated that it was selected because of a 21‐fold increase in mAb M2 affinity compared with full‐length FLAG‐PRAI. Remarkably, this truncated barrel was found to be soluble, structured, thermostable and monomeric, implying that it represents a genuine subdomain of PRAI and providing further evidence that such subdomains have played an important role in the evolution of the (βα)8‐barrel fold.
Structure and activity of the atypical serine kinase Rio1
Authors: LaRonde‐LeBlanc Nicole , Guszczynski Tad , Copeland Terry , Wlodawer Alexander
Published: July 2005

Rio1 is the founding member of the RIO family of atypical serine kinases that are universally present in all organisms from archaea to mammals. Activity of Rio1 was shown to be absolutely essential in Saccharomyces cerevisiae for the processing of 18S ribosomal RNA, as well as for proper cell cycle progression and chromosome maintenance. We determined high‐resolution crystal structures of Archaeoglobus fulgidus Rio1 in the presence and absence of bound nucleotides. Crystallization of Rio1 in the presence of ATP or ADP and manganese ions demonstrated major conformational changes in the active site, compared with the uncomplexed protein. Comparisons of the structure of Rio1 with the previously determined structure of the Rio2 kinase defined the minimal RIO domain and the distinct features of the RIO subfamilies. We report here that Ser108 represents the sole autophosphorylation site of A. fulgidus Rio1 and have therefore established its putative peptide substrate. In addition, we show that a mutant enzyme that cannot be autophosphorylated can still phosphorylate an inactive form of Rio1, as well as a number of typical kinase substrates.
Nuclear import of mPER3 in Xenopus oocytes and HeLa cells requires complex formation with mPER1
Authors: Loop Susanne , Pieler Tomas
Published: July 2005

Several transcription factors with the function of setting the biological clock in vertebrates have been described. A detailed understanding of their nucleocytolasmic transport properties may uncover novel aspects of the regulation of the circadian rhythm. This assumption led us to perform a systematic analysis of the nuclear import characteristics of the different murine PER and CRY proteins, using Xenopus oocytes and HeLa cells as experimental systems. Our major finding is that nuclear import of mPER3 requires complex formation with mPER1. We further show that the nuclear localization signal (NLS) function of mPER1 and not activation of a masked NLS in mPER3 is critical for the import of the mPER1–mPER3 complex. Finally, and as previously described in other cell systems, nuclear import of mPER proteins in Xenopus oocytes correlates positively with their phosphorylation.
Structural analysis of the jacalin‐related lectin MornigaM from the black mulberry (Morus nigra) in complex with mannose
Authors: Rabijns Anja , Barre Annick , Van Damme Els J. M. , Peumans Willy J. , De Ranter Camiel J. , Rougé Pierre
Published: July 2005

The structures of MornigaM and the MornigaM–mannose complex have been determined at 1.8 Å and 2.0 Å resolution, respectively. Both structures adopt the typical β‐prism motif found in other jacalin‐related lectins and their tetrameric assembly closely resembles that of jacalin. The carbohydrate‐binding cavity of MornigaM readily binds mannose. No major structural rearrangements can be observed in MornigaM upon binding of mannose. These results allow corroboration of the structure–function relationships within the small group of Moraceae lectins.