特矮稻ED基因的遗传定位和分析

赤霉素（GA3）鉴定表明,一种新型特矮稻（命名为‘特矮稻-2’）的GA3信号转导途径正常,施加外源GA3不能恢复到正常植株的高度,说明此种矮稻的矮化机制与GA3无关。来源于组合‘特矮稻-2’ב日本晴’的F2群体的遗传分析表明,‘特矮稻-2’的特矮性状受1对隐性基因控制。采用SSR分子标记,将该矮秆基因定位于第12染色体上的RM519和RM235标记之间,遗传距离分别为15.9和22.0cM,该基因暂命名为ED。     

Anti-tumor agents 255: novel glycyrrhetinic acid-dehydrozingerone conjugates as cytotoxic agents

Esterification of glycyrrhetinic acid (GA) with dehydrozingerone (DZ) resulted in a novel cytotoxic GA-DZ conjugate. Based on this exciting finding, we conjugated eleven different DZ analogs with GA or other triterpenoids, including oleanoic acid (OA) or ursolic acid (UA). In an in vitro anti-cancer assay using nine different human tumor cell lines, most of the GA-DZ conjugates showed significant potency. Particularly, compounds 5, 29, and 30 showed significant cytotoxic effects against LN-Cap, 1A9, and KB cells with ED(50) values of 0.6, 0.8, and 0.9 microM, respectively. Similar conjugates between DZ and OA or UA were inactive suggesting that the GA component is critical for activity. Notably, although GA-DZ conjugates showed potent cytotoxic activity, the individual components (GA and DZ analogs) were inactive. Thus, GA-DZ conjugates are new chemical entities and represent interesting hits for anti-cancer drug discovery and development.     

Las 3D/3D+ como herramienta de valoración geriátrica rápida y de adecuación del recurso asistencial al alta de los Servicios de Urgencias

ObjectiveAssess the 3D/3D+ rapid geriatric assessment tool for the early detection of frailty, its usefulness to identify the effects of the acute process on the functional, physical, cognitive and socioenvironmental dimensions, as well as the medications that may have triggered the patient's reason for visit. Finally, assess the usefulness of 3D/3D+ together with the clinical diagnosis to adequate care resource at discharge from the emergency department (ED).MethodRetrospective observational cohort study. Patients ≥75 years old, with clinical complexity visited at the ED were included. Basal frailty status was assessed using 3D (basal component), and the multidimensional impact of the acute process using 3D+ (current component). The main dependent variable was adequacy of the care resource at ED discharge.Results278 patients were included, mean age 86 years (interquartile range: 83–90), 59.7% were women. According to the basal component (3D), 83.1% (95%CI: 78.2–87.3) presented some degree of frailty. The current component (3D+) was altered in 60.1% (95%CI: 54.1–65.9). The adequacy of ED discharge was correct in 96.4% (95%CI: 93.0–98.0). One out of 4 patients was admitted to a medicine ward.Conclusions3D/3D+ facilitates an optimal model of emergency care adapted to patients ≥ 75 years old treated in EDs. It stratifies the level of frailty (3D), detects the severity of patients’ acute problems (3D+) and contributes to decision-making regarding the most appropriate care resource at ED discharge.     

专一识别脱落酸甲酯的单克隆抗体的制备与应用

专一识别２－顺（Ｓ）ＡＢＡ甲酯的单克隆抗体来源于以ＡＢＡ分子中的１－ＣＯＯＨ为偶联位点合成的免疫原。它与游离态ＡＢＡ和结合态ＡＢＡ葡萄糖酯的交叉反应仅分别为１％与３．５％,而与ＡＢＡ类似物,如２－顺－黄质醛、紫黄质以及ＡＢＡ的２－反式异构体和（Ｒ）－对映体则无交叉反应。利用该抗体建立的高度灵敏和精确的ＡＢＡｍｅ酶联免疫测定法,其检测线性范围为０．０４８～１．５２ｐｍｏｌ。通过ＡＢＡｍｅＥＬＩＳＡ和ＧＡ１＋３ＥＬＩＳＡ分析可知羊蹄叶片衰老与内源ＧＡ１＋３／ＡＢＡ比值的下降有关。     

The Nonphosphorylative Entner-Doudoroff Pathway in the Thermoacidophilic Euryarchaeon Picrophilus torridus Involves a Novel 2-Keto-3-Deoxygluconate- Specific Aldolase

The pathway of glucose degradation in the thermoacidophilic euryarchaeon Picrophilus torridus has been studied by in vivo labeling experiments and enzyme analyses. After growth of P. torridus in the presence of [1-¹³C]- and [3-¹³C]glucose, the label was found only in the C-1 and C-3 positions, respectively, of the proteinogenic amino acid alanine, indicating the exclusive operation of an Entner-Doudoroff (ED)-type pathway in vivo. Cell extracts of P. torridus contained all enzyme activities of a nonphosphorylative ED pathway, which were not induced by glucose. Two key enzymes, gluconate dehydratase (GAD) and a novel 2-keto-3-deoxygluconate (KDG)-specific aldolase (KDGA), were characterized. GAD is a homooctamer of 44-kDa subunits, encoded by Pto0485. KDG aldolase, KDGA, is a homotetramer of 32-kDa subunits. This enzyme was highly specific for KDG with up to 2,000-fold-higher catalytic efficiency compared to 2-keto-3-deoxy-6-phosphogluconate (KDPG) and thus differs from the bifunctional KDG/KDPG aldolase, KD(P)GA of crenarchaea catalyzing the conversion of both KDG and KDPG with a preference for KDPG. The KDGA-encoding gene, kdgA, was identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) as Pto1279, and the correct translation start codon, an ATG 24 bp upstream of the annotated start codon of Pto1279, was determined by N-terminal amino acid analysis. The kdgA gene was functionally overexpressed in Escherichia coli. Phylogenetic analysis revealed that KDGA is only distantly related to KD(P)GA, both enzymes forming separate families within the dihydrodipicolinate synthase superfamily. From the data we conclude that P. torridus degrades glucose via a strictly nonphosphorylative ED pathway with a novel KDG-specific aldolase, thus excluding the operation of the branched ED pathway involving a bifunctional KD(P)GA as a key enzyme.Comparative analyses of sugar-degrading pathways in members of the domain Archaea revealed that all species analyzed so far degrade glucose and glucose polymers to pyruvate via modification of the classical Embden-Meyerhof (EM) and Entner-Doudoroff (ED) pathways found in bacteria and eukarya. Modified EM pathways were reported for hyperthermophilic archaea, including, e.g., the strictly fermentative Thermococcales and Desulfurococcales, the sulfur-reducing Thermoproteus tenax, and the microaerophilic Pyrobaculum aerophilum. These pathways differ from the classical EM pathway by the presence of several novel enzymes and enzyme families, catalyzing, e.g., the phosphorylation of glucose and fructose-6-phosphate, isomerization of glucose-6-phosphate, and oxidation of glyceraldehyde-3-phosphate (18, 22, 25).Modified ED pathways have been proposed for aerobic archaea, including halophiles, and thermoacidophilic crenarchaea, such as Sulfolobus species, and the euryarchaea Thermoplasma acidophilum and Picrophilus torridus. The anaerobic Thermoproteus tenax, which degrades glucose predominantly via a modified EM pathway, also utilizes—to a minor extent (<20%)—a modified ED pathway for glucose degradation. The following ED pathway modifications have been reported in archaea (25). A semiphosphorylative ED pathway was reported in halophilic archaea. Accordingly, glucose is converted to 2-keto-3-deoxy-6-gluconate (KDG) via glucose dehydrogenase and gluconate dehydratase. KDG is then phosphorylated by KDG kinase to 2-keto-3-deoxy-6-phosphogluconate (KDPG), which is split by KDPG aldolase to pyruvate and glyceraldehyde-3-phosphate (GAP). GAP is further converted to form another pyruvate via common reactions of the EM pathway, i.e., phosphorylative GAP dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, enolase, and pyruvate kinase. The net ATP yield of this pathway is 1 ATP/mol glucose.From initial enzyme studies of the thermoacidophilic archaea Sulfolobus solfataricus, Thermoplasma acidophilum, and Thermoproteus tenax, a nonphosphorylative ED pathway was proposed (25). In this modification of the ED pathway, glucose is converted to KDG via glucose dehydrogenase and gluconate dehydratase, as in the semiphosphorylative pathway, but then the steps differ as follows: KDG is cleaved into pyruvate and glyceraldehyde via 2-keto-3-deoxygluconate-specific aldolase (KDGA). The subsequent oxidation of glyceraldehyde to glycerate involves either NAD(P)⁺-dependent dehydrogenases or oxidoreductases. Glycerate is then phosphorylated by a specific kinase to 2-phosphoglycerate, which is finally converted to pyruvate via enolase and pyruvate kinase. This modification of the ED pathway was called “nonphosphorylative” since it is not coupled with net ATP synthesis.However, recent comparative genomic studies and refined enzyme analyses suggest that the crenarchaea Sulfolobus and Thermoproteus utilize a so-called branched ED pathway, in which a semiphosphorylated route is simultaneously operative in addition to the nonphosphorylative route (25, 32). Accordingly, the semiphosphorylated route involves—via KDG kinase—the phosphorylation of KDG to KDPG, which is then cleaved to pyruvate and GAP by means of a bifunctional KDG/KDPG aldolase, KD(P)GA. GAP is then converted to another pyruvate via nonphosphorylative GAP dehydrogenase (GAPN), phosphoglycerate mutase, enolase, and pyruvate kinase. The net ATP yield of the branched ED pathway is zero. In support of this pathway, the genes encoding gluconate dehydratase, bifunctional KD(P)GA, KDG kinase, and GAPN were found to be clustered in Sulfolobus solfataricus (see Discussion) and Thermoproteus tenax. The key enzyme of the proposed branched ED pathway is the bifunctional KD(P)GA, which catalyzes the cleavage of KDG to pyruvate and glyceraldehyde and cleavage of KDPG to pyruvate and glyceraldehyde-3-phosphate. This bifunctional aldolase, which has been characterized from S. solfataricus, was found to be identical to a previously described KDG aldolase of the same organism; however, its catalytic property to also utilize KDPG as a substrate has been recognized only recently. In fact, the bifunctional KD(P)GA showed a higher catalytic efficiency for KDPG than for KDG (1, 14). Crystal structures of bifunctional KD(P)GAs of S. solfataricus and T. tenax have been reported (16, 27, 30; G. Taylor [United Kingdom], unpublished data).The branched ED pathway in S. solfataricus has been reported to be promiscuous and therefore represents an equivalent degradation route for both glucose and its C-4 epimer, galactose. Accordingly, glucose dehydrogenase, gluconate dehydratase, KDG kinase, and bifunctional KD(P)GA were found to catalyze the conversion of both glucose and galactose and the corresponding subsequent intermediates, i.e., gluconate/galactonate, KDG/KDGal (KDGal stands for 2-keto-3-deoxygalactonate), and KDPG/KDPGal (KDPGal stands for 2-keto-3-deoxy-6-phosphogalactonate) (4, 12-14).In contrast to crenarchaea, the modified ED pathway in the thermoacidophilic euryarchaea Thermoplasma acidophilum and Picrophilus torridus has not been studied in detail. Enzyme measurements in cell extracts and the characterization of few enzymes suggest the operation of a nonphosphorylative ED pathway in these organisms (2, 3, 17, 19, 25). However, in vivo evidence for the operation of an ED-type pathway, e.g., by ¹³C-labeling experiments with growing cultures, has not been provided yet. Furthermore, the KDG aldolase activity measured in cell extracts of P. torridus and T. acidophilum has not been purified and characterized, in particular with respect to substrate specificity, and the genes encoding these enzymes have not been identified. The biochemical analysis of this aldolase is crucial to define the enzyme as a KDG-specific aldolase, indicative of a nonphosphorylative ED pathway, or as bifunctional KD(P)GA, indicative of the branched ED pathway as proposed for the crenarchaea Sulfolobus and Thermoproteus.In this communication we studied the sugar-degrading pathway in P. torridus by in vivo labeling experiments with [¹³C]glucose, by enzyme measurements, and by characterization of two key enzymes, gluconate dehydratase and KDG aldolase. The data indicate that P. torridus utilizes a strict nonphosphorylative ED pathway, involving a novel KDG-specific aldolase as a key enzyme, and thus exclude the operation of a branched ED pathway, as in crenarchaea involving a bifunctional KD(P)GA as a key enzyme.     

Tracing the origin of HLA-DRB1 alleles by microsatellite polymorphism.

We analyzed the origin of allelic diversity at the class II HLA-DRB1 locus, using a complex microsatellite located in intron 2, close to the polymorphic second exon. A phylogenetic analysis of human, gorilla, and chimpanzee DRB1 sequences indicated that the structure of the microsatellite has evolved, primarily by point mutations, from a putative ancestral (GT)x(GA)y-complex-dinucleotide repeat. In all contemporary DRB1 allelic lineages, with the exception of the human *04 and the gorilla *08 lineages, the (GA)y repeat is interrupted, often by a G-->C substitution. In general, the length of the 3' (GA)y repeat correlates with the allelic lineage and thus evolves more slowly than a middle (GA)z repeat, whose length correlates with specific alleles within the lineage. Comparison of the microsatellite sequence from 30 human DRB1 alleles showed the longer 5' (GT)x to be more variable than the shorter middle (GA)z and 3' (GA)y repeats. Analysis of multiple samples with the same exon sequence, derived from different continents, showed that the 5' (GT)x repeat evolves more rapidly than the middle (GA)z and the 3' (GA)y repeats, which is consistent with findings of a higher mutation rate for longer tracts. The microsatellite-repeat-length variation was used to trace the origin of new DRB1 alleles, such as the new *08 alleles found in the Cayapa people of Ecuador and the Ticuna people of Brazil.     

Sequence optimization as an alternative to de novo analysis of tandem mass spectrometry data

MOTIVATION: Peptide identification following tandem mass spectrometry (MS/MS) is usually achieved by searching for the best match between the mass spectrum of an unidentified peptide and model spectra generated from peptides in a sequence database. This methodology will be successful only if the peptide under investigation belongs to an available database. Our objective is to develop and test the performance of a heuristic optimization algorithm capable of dealing with some features commonly found in actual MS/MS spectra that tend to stop simpler deterministic solution approaches. RESULTS: We present the implementation of a Genetic Algorithm (GA) in the reconstruction of amino acid sequences using only spectral features, discuss some of the problems associated with this approach and compare its performance to a de novo sequencing method. The GA can potentially overcome some of the most problematic aspects associated with de novo analysis of real MS/MS data such as missing or unclearly defined peaks and may prove to be a valuable tool in the proteomics field. We assess the performance of our algorithm under conditions of perfect spectral information, in situations where key spectral features are missing, and using real MS/MS spectral data.     

Clinical and Genetic Factors Associated with Progression of Geographic Atrophy Lesions in Age-Related Macular Degeneration

Worldwide, age-related macular degeneration (AMD) is a serious threat to vision loss in individuals over 50 years of age with a pooled prevalence of approximately 9%. For 2020, the number of people afflicted with this condition is estimated to reach 200 million. While AMD lesions presenting as geographic atrophy (GA) show high inter-individual variability, only little is known about prognostic factors. Here, we aimed to elucidate the contribution of clinical, demographic and genetic factors on GA progression. Analyzing the currently largest dataset on GA lesion growth (N = 388), our findings suggest a significant and independent contribution of three factors on GA lesion growth including at least two genetic factors (ARMS2_rs10490924 [P < 0.00088] and C3_rs2230199 [P < 0.00015]) as well as one clinical component (presence of GA in the fellow eye [P < 0.00023]). These correlations jointly explain up to 7.2% of the observed inter-individual variance in GA lesion progression and should be considered in strategy planning of interventional clinical trials aimed at evaluating novel treatment options in advanced GA due to AMD.     

Impacto del apoyo familiar en la presencia de quejas depresivas en personas mayores de Santiago de Chile

Introduction

Epidemiological changes can have an effect on social and, and in particular, family ties, which are important elements in the mental health of older people. The objective of this study was to evaluate the impact of family support on depressive disorders in older people of the community.

Material and methods

Face to face interviews were conducted on a representative sample of adults 60 years and older, living in urban area of Santiago de Chile. The information on depressive disorders was related to family composition, emotional and instrumental support, presence of conflict, health self-perception, functionality and self-efficiency. Data were analyzed using logistic regression models.

Results

From a total of 394 participants, 62% females, mean age 74 years (SD=8.1), 16% felt depressed almost every day. Depressive disorders were significantly associated in regression models with impaired self-perception of health and efficacy, lower instrumental support, and with the presence of conflict. The variable that most contributed to the model was self-rated poor health, increasing the odds of depressive disorders by 3.2.

Conclusions

Poor perception of health was the main determining factor for depressive complaints in older people, followed by lower family support, specifically instrumental support, and the presence of conflict. This information can help future programs in order to improve the quality of life in older people.     

Desarrollo de un instrumento de registro de implicación/engagement en la actividad para la observación sistemática de personas mayores con deterioro cognitivo

Introduction

As the level of cognitive impairment in people with dementia increases, it seems that the interventions aimed at this group do not obtain the expected results. Thus, it is clear that there is a need to develop specific assessment tools. One of the important aspects in people with dementia is the engagement, involvement in task and activities. Engagement is considered a quality of life and quality of care indicator. The aim of the study is to develop an Engagement recording tool for mapping people with dementia, and to obtain reliability measures.

Method

The present paper aims to present the current development of engagement behaviours. The pilot study had a sample of 19 people distributed into two groups, which were observed in order to obtain inter-rater reliability measurements using the percentage of inter-rater agreement.

Results

An observational mapping instrument was developed that achieved a high inter-rater reliability.

Conclusion

The Engagement recording tool makes it possible to gather promising results on the effects of the interventions for people with severe dementia. On the other hand, these results point to the possibilities of more specific tools to assess the different interventions which aim is to improve quality of life and quality of care in people with dementia.     

Poison de flèches de l'Indochine française

Through an examination of business relationships in the textile industry of Surat, a city in western India, this article evaluates different theories about the importance of social trust in economic development. The case study of Surat raises questions about models that posit a necessary expansion of broad civic ties or legal‐bureaucratic structures at the expense of close personal ties as a basis for industrial development. Surat's business people rely most strongly upon relationships to particular kins‐people, caste‐mates, and co‐religionists rather than broader civic bonds, formal legal controls, or bureaucratic systems as foundations for business trust. Although the expansion of the city's textile industry has created a greater need among the local population for impersonal, universalizing types of social trust, this article argues that these forms, show little sign of replacing personalized trust as the primary basis for local economic activity.     

Desarrollo y validación de un instrumento observacional para la evaluación del bienestar en personas con demencia desde la perspectiva de la atención centrada en la persona: Listado de Indicadores de Bienestar

IntroductionWithin the context of Person Centred Care, the present paper shows the creation and validation process of an observational tool for the assessment of the wellbeing of people with dementia, from a perspective that seeks to highlight the effects that the physical and social environment have on the person, and how these are reflected in the well-being.MethodsThe List of Wellbeing Indicators (LIBE) was created following an inductive iterative process with professionals from different disciplines, until the validated version was reached. It was then validated in two successive studies with a sample of 79 people with dementia. Discrimination capacity of the scale indicators, internal consistency, inter-rater reliability, and convergent and divergent validity were determined.ResultsAn internal consistency of Cronbach́s alpha 0.81 was obtained. The inter-rater reliability, analysing intraclass correlation coefficient (ICC) within the 3 raters, was significant for all the indicators in the tool, with scores between 0.59-1.00. Convergent validity was studied comparing scores in each LIBE indicator with scores in each QUALID indicator, and some significant associations were found between response categories in both tools. For the discriminant validity, the scores obtained in each LIBE indicator were compared with the scores in each PAINAD-Sp item, and no significant associations were found.ConclusionLIBE offers an observational measure of behaviours that can be considered well-being indicators in people with dementia living in residential care. LIBE is a valid and reliable tool that offers a different perspective of measuring a construct that has been infrequently explored in dementia population. Is also an easy to apply tool, with different uses (clinical, intervention, research), and applicable for professionals of several disciplines.     

Light Alters Cytosolic and Plastidic Phosphorylase Distribution in Pearl Millet Leaves

Treatment of pollinated pea (Pisum sativum L. cv Alaska, line V1) ovaries with 3,5-dioxo-4-butyryl-cyclohexane carboxylic acid ethyl ester (LAB), an acylcyclohexanedione derivative that competitively inhibits 2-oxoglutarate-dependent gibberellin (GA) dioxygenases, caused a reduction of pod elongation proportional to the amount of inhibitor applied. The effect of LAB was counteracted by GA1 and GA3, and partially by GA20. The inhibitor decreased the contents of GA1 and GA3 (the purported active GAs) and GA8, increased those of GA19 and GA20, and did not affect that of GA29 in both the pod and the developing seeds. These results provide evidence that GA1 and/or GA3 control pod development in pea and show that GA20 is not active per se. In contrast to its effect on pollinated ovaries, LAB promoted parthenocarpic development of unpollinated ovaries, which is associated with an increase of GA1 and GA8 content. The inhibitor enhanced the response of unpollinated ovaries to GA1 and GA20, but it did not alter the response to GA3. LAB is proposed to promote parthenocarpic development and enhance the response to exogenous GAs by blocking the 2[beta]-hydroxylation of GA1 more efficiently than 3[beta]-hydroxylation of GA20.     

Ectopic expression of pumpkin gibberellin oxidases alters gibberellin biosynthesis and development of transgenic Arabidopsis plants

Immature pumpkin (Cucurbita maxima) seeds contain gibberellin (GA) oxidases with unique catalytic properties resulting in GAs of unknown function for plant growth and development. Overexpression of pumpkin GA 7-oxidase (CmGA7ox) in Arabidopsis (Arabidopsis thaliana) resulted in seedlings with elongated roots, taller plants that flower earlier with only a little increase in bioactive GA4 levels compared to control plants. In the same way, overexpression of the pumpkin GA 3-oxidase1 (CmGA3ox1) resulted in a GA overdose phenotype with increased levels of endogenous GA4. This indicates that, in Arabidopsis, 7-oxidation and 3-oxidation are rate-limiting steps in GA plant hormone biosynthesis that control plant development. With an opposite effect, overexpression of pumpkin seed-specific GA 20-oxidase1 (CmGA20ox1) in Arabidopsis resulted in dwarfed plants that flower late with reduced levels of GA4 and increased levels of physiological inactive GA17 and GA25 and unexpected GA34 levels. Severe dwarfed plants were obtained by overexpression of the pumpkin GA 2-oxidase1 (CmGA2ox1) in Arabidopsis. This dramatic change in phenotype was accompanied by a considerable decrease in the levels of bioactive GA4 and an increase in the corresponding inactivation product GA34 in comparison to control plants. In this study, we demonstrate the potential of four pumpkin GA oxidase-encoding genes to modulate the GA plant hormone pool and alter plant stature and development.     

类风湿关节炎与痛风关节炎患者身心健康、炎症状态及免疫功能的比较

目的:比较类风湿关节炎与痛风关节炎患者身心健康、炎症及免疫状态的差异。方法:选择我院2016年5月至2018年8月收治的66例类风湿关节炎患者及63例痛风关节炎患者作为研究对象,并将之分为类风湿关节炎(Rheumatoid arthritis,RA)组及痛风关节炎(Gouty arthritis,GA)组。同时选取60例体检健康人群作为健康组。观察比较三组研究对象身心健康评分、炎症及免疫相关指标水平。结果:RA组及GA组身心健康评分显著低于健康组(P0.05),炎症及免疫相关指标水平显著高于健康组(P0.05)。RA组患者总体健康评分、社会功能评分、红细胞沉降率(ESR)、C反应蛋白(CRP)、免疫球蛋白G(Ig G)、免疫球蛋白A(Ig A)、免疫球蛋白M(Ig M)及补体3(C3)水平显著高于GA组(P0.05),白细胞(WBC)总数明显少于GA组(P0.05),两组患者生理功能、生理职能、身体疼痛、活力、情感职能、心理健康评分及补体4(C4)水平比较差异不显著(P0.05)。结论:相较于健康人群,类风湿关节炎患者及痛风关节炎患者身心健康状况差,易出现炎症、免疫功能紊乱现象,且类风湿关节炎患者炎症程度较深,免疫功能影响更大。     

A de novo designed 11 kDa polypeptide: Model for amyloidogenic intrinsically disordered proteins

A de novo polypeptide GH₆[(GA)₃GY(GA)₃GE]₈GAH₆ (YE8) has a significant number of identical weakly interacting β‐strands with the turns and termini functionalized by charged amino acids to control polypeptide folding and aggregation. YE8 exists in a soluble, disordered form at neutral pH but is responsive to changes in pH and ionic strength. The evolution of YE8 secondary structure has been successfully quantified during all stages of polypeptide fibrillation by deep UV resonance Raman (DUVRR) spectroscopy combined with other morphological, structural, spectral, and tinctorial characterization. The YE8 folding kinetics at pH 3.5 are strongly dependent on polypeptide concentration with a lag phase that can be eliminated by seeding with a solution of folded fibrillar YE8. The lag phase of polypeptide folding is concentration dependent leading to the conclusion that β‐sheet folding of the 11‐kDa amyloidogenic polypeptide is completely aggregation driven. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 607–618, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Molecular and physiological characterization of Arabidopsis GAI alleles obtained in targeted Ds-tagging experiments

Bioactive gibberellin (GA) is an essential regulator of vascular plant development. The GAI gene of Arabidopsis thaliana (L.) Heynh. encodes a product (GAI) that is involved in GA signalling. The dominant mutant gai allele encodes an altered product (gai) that confers reduced GA responses, dwarfism, and elevated endogenous GA levels. Recessive, presumed loss-of-function alleles of GAI confer normal height and resistance to the GA biosynthesis inhibitor paclobutrazol. One explanation for these observations is that GAI is a growth repressor whose activity is opposed by GA, whilst gai retains a constitutive repressor activity that is less affected by GA. Previously, we described gai-t6, a mutant allele which contains an insertion of a maize Ds transposable element into gai. Here we describe the molecular and physiological characterization of two further alleles (gai-t5, gai-t7) identified during the Ds mutagenesis experiment. These alleles confer paclobutrazol resistance and normal endogenous GA levels. Thus the phenotype conferred by gai-t5, gai-t6 and gai-t7 is not due to elevated GA levels, but is due to loss of gai, a constitutively active plant growth repressor.