bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expansins in growing tomato leaves
Authors: Keller Elvira , Cosgrove Daniel J. 
Published: October 2010

SummaryAn expansin‐like protein from growing tomato leaves was identifed by its ability to restore the ‘acid‐growth’ response to heat‐inactivated tomato walls and by its similarity to expansins from cucumber hypocotyls. Native walls from growing tomato leaves exhibit an endogenous acid‐induced extension (creep) that resembles in various biochemical characteristics the acid‐growth activity of cucumber hypocotyls. For example, the acid‐growth activity is lost when the walls of tomato leaves are briefly heated and is largely restored by addition of a crude protein extract from the walls of growing leaves. Wall proteins from growing leaves enhance the stress relaxation spectrum of tomato walls in a fashion characteristic of cucumber expansins. HPLC fractionation of the crude wall protein from tomato leaves yielded an active fraction containing a major 27 kDa protein that cross‐reacts with an antibody raised against cucumber expansin. The results show that tomato leaf walls possess at least one expansin that is responsible for the acid‐growth property of leaves and indicate that cell wall extension in leaves shares an underlying protein mechanism common to cell wall expansion in stems.
The S locus receptor kinase gene encodes a soluble glycoprotein corresponding to the SRK extracellular domain in Brassica oleracea
Authors: Giranton Jean‐Loïc , Ariza María José , Dumas Christian , Cock J. Mark , Gaude Thierry 
Published: October 2010

SummarySelf‐incompatibility in Brassica is controlled by the S locus which contains at least two genes. SLG encodes a secreted S locus glycoprotein whilst SRK encodes a putative S locus receptor kinase which consists of three domains: an extracellular domain sharing extensive sequence identity with SLG, a transmembrane region, and a cytoplasmic domain exhibiting a serine/threonine protein kinase activity. Here, the existence of truncated forms of the SRK protein corresponding to the extracellular domain of the putative receptor is reported. These proteins were detected by an antibody which recognizes the N‐terminus of SRK3 and, in an F2 progeny segregating for the S3 haplotype, were only expressed in plants possessing the S3 haplotype. The truncated SRK proteins were expressed specifically in stigmas but, unlike the membrane‐spanning SRK3 protein, were soluble and occurred as four different glycoforms sharing the same amino acid backbone as shown by deglycosylation experiments. Several SRK3 transcripts that may code for these truncated SRK3 proteins have been identified by RACE PCR, stigma cDNA library screening and RNA blot analysis. These transcripts are apparently generated by a combination of alternative splicing and the use of alternative polyadenylation signals. The existence of truncated forms of the S locus receptor kinase highlights some similarities between plant and animal receptor kinases. In animals, soluble extracellular domains of receptors have been described and, in some cases, have been shown to play a role in the modulation of signal transduction. By analogy, the soluble, truncated SRK proteins may play a similar role in the self‐incompatibility response.
A microtubule‐associated protein in maize is expressed during phytochrome‐induced cell elongation
Authors: Nick Peter , Lambert Anne‐Marie , Vantard Marylin 
Published: October 2010

SummaryPlants can adapt their shape to environmental stimuli. This response is mediated by the reorganization of cortical microtubules, a unique element of the cytoskeleton. However, the molecular base of this response has remained obscure so far. In an attempt to solve this problem, signal‐dependent changes in the pattern of microtubule‐binding proteins were analysed during coleoptile elongation in maize, that is, under the control of the plant photoreceptor phytochrome. Two putative MAPs of 100 kDa (P100) and 50 kDa apparent molecular weights were identified in cytosolic extracts from non‐elongating and elongating cells. Both proteins co‐assembled with endogenous tubulin, bound to neurotubules and were immunologically related to the neural MAP τ: the P100 protein, depending on the physiological situation, was manifest as a double band and was always found to be heat‐stable. In contrast, the 50 kDa MAP was heat‐stable only for particular tissues and physiological treatments. The P100 protein was present in all tissues, however in a reduced amount in elongating coleoptiles. The 50 kDa MAP was expressed exclusively upon induction of phytochrome‐dependent cell elongation. As shown by immunofluorescence double‐staining, an epitope shared by both proteins colocalized with cortical microtubules in situ, but exclusively in elongating cells. In non‐elongating cells, only the nuclei were stained. Partially purified nuclei from elongating cells were enriched in P100, whereas the 50 kDa MAP became enriched in a partially purified plasma membrane fraction.
A repetitive DNA fragment carrying a hot spot for de novo DNA methylation enhances expression variegation in tobacco and petunia
Authors: Lohuis Michael ten , Müller Andreas , Heidmann Iris , Niedenhof Ingrid , Meyer Peter 
Published: October 2010

SummaryA 1.6 kb repetitive DNA sequence (RPS) from Petunia hybrida was identified that destabilizes expression of a GUS marker transgene. Following polyethylene glycol (PEG)‐mediated tobacco and petunia protoplast transformations, GUS expression patterns analysed on callus and plant levels were clearly more variable when constructs contained the RPS sequence. The effect on transgens expression required chromosomal integration since the two different RPS constructs employed did not exhibit reduced levels of GUS activities in transient assays. DNA methylation analysis implies a hypermethylated default state of endogenous RPS copies present in the petunia genome. Analysis of the transgens DNA in different transgenic tobacco plants showed almost complete hypermethylation of a particular Hhal site of the RPS sequence. It is proposed that, due to the presence of specific signals within the RPS region or based on interaction of RPS with other endogenous homologous sequences, RPS functions as an initiation region for de novo methylation and induces expression variegation in adjacent sequences.
Genetic engineering of the multicellular green algaVolvox: a modified and multiplied bacterial antibiotic resistance gene as a dominant selectable marker
Authors: Hallmann Armin , Rappel Annette 
Published: October 2010

Summary The green alga

Volvox

represents the simplest multicellular organism:

Volvox

is composed of only two cell types, somatic and reproductive.

Volvox

, therefore, is an attractive model system for studying various aspects of multicellularity. With the biolistic nuclear transformation of

Volvox carteri

, the powerful molecular genetic manipulation of this organism has been established, but applications have been restricted to an auxotrophic mutant serving as the DNA recipient. Therefore, a dominant selectable marker working in all strains and mutants of this organism is required. Among several gene constructs tested, the most advantageous results were obtained with a chimeric gene composed of the coding sequence of the bacterial

ble

gene, conferring resistance to the antibiotic zeocin, modified with insertions of two endogenous introns from the

Volvox

arylsulfatase gene and fused to 5′ and 3′ untranslated regions from the

Volvox

β2‐tubulin gene. In the most suitable plasmid used, the gene dosage was increased 16‐fold by a technique that allows exponential multiplication of a DNA fragment. Co‐transformation of this plasmid and a non‐selectable plasmid allowed the identification of zeocin resistant transformants with nuclear integration of both selectable and non‐selectable plasmids. Stable expression of the

ble

gene and of genes from several non‐selectable plasmids is demonstrated. The modified

ble

gene provides the first dominant marker for transformation of both wild‐type and mutant strains of

Volvox

.
The universally conserved HCF101 protein is involved in assembly of [4Fe‐4S]‐cluster‐containing complexes in Arabidopsis thaliana chloroplasts
Authors: Lezhneva Lina , Amann Katrin , Meurer Jörg 
Published: October 2010

SummaryThe seedling‐lethal nuclear Arabidopsis hcf101 (high chlorophyll fluorescence) mutant is impaired in photosynthesis and complemented by the wild‐type HCF101 cDNA. Photosystem I (PSI) activity is abolished, and PSI core complexes fail to accumulate in hcf101, whereas levels of other thylakoid membrane proteins are unaffected. Northern and in vivo labelling analyses as well as studies on polysome loading show that PSI transcript levels and translation rates of proteins, which belong to PSI, are normal in hcf101. PSI‐specific fluorescence at 77 K is shifted from 735 to 728 nm in hcf101, indicating that exitons cannot efficiently be transferred to the PSI reaction centre, whereby the PSI antenna is almost unaffected. Mutant plants not only fail to accumulate mature PSI, which contains three [4Fe‐4S]clusters (FSCs), but also are characterized by reduced levels of the soluble FSC‐containing complex ferredoxin‐thioredoxin reductase (FTR) in the stroma. Inhibited FTR maturation is not a secondary effect stemming from lack of PSI because the mutant hcf145, which also lacks PSI, accumulates FTR at normal levels. Levels of the [2Fe‐2S] cluster‐containing soluble and membrane proteins, ferredoxin and PetC, respectively, were unchanged in hcf101 plants. These data suggest a specific role of HCF101 in FSC biogenesis. HCF101 is plastid localized and belongs to an ancient and universally conserved family of P‐loop ATPases previously designated as the ‘MRP’ (metGrelated protein) family. The function identified for HCF101 suggests a new designation, FSC, for this family.
Involvement of the R2R3‐MYB, AtMYB61, in the ectopic lignification and dark‐photomorphogenic components of the det3 mutant phenotype
Authors: Newman Lisa J. , Perazza Daniel E. , Juda Lusanda , Campbell Malcolm M. 
Published: October 2010

SummaryOverexpression of a pine MYB, PtMYB4, in Arabidopsis caused ectopic lignin deposition and allowed the plants to undergo photomorphogenesis even when they were grown in the dark. The phenotype caused by PtMYB4 overexpression was reminiscent of the previously characterised dark‐photomorphogenic mutant, de‐etiolated 3 (det3); consequently, we tested the hypothesis that MYB misexpression may explain aspects of the det3 phenotype. We show here that AtMYB61, a member of the Arabidopsis R2R3‐MYB family, is misexpressed in the det3 mutant. Semi‐quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) experiments suggested that AtMYB61 was misexpressed in a det3 background relative to wild‐type plants. Examination of AtMYB61 promoter activity in a det3 background showed that the spatial control of AtMYB61 expression was lost. In order to determine if such misexpression could explain the mutant phenotype, AtMYB61 was overexpressed in wild‐type Arabidopsis plants. Transgenic plants that overexpressed AtMYB61 had the same ectopic lignification and dark‐photomorphogenic phenotype as that of the det3 mutant. In order to test if AtMYB61 was necessary for these aspects of the det3 phenotype, AtMYB61 expression was downregulated in det3 plants in both antisense and sense suppression experiments. Suppression of AtMYB61 in a det3 mutant background restored all mutant phenotypes of the det3 mutant associated with development in the dark. Taken together, these results suggest that AtMYB61 misexpression was both sufficient and necessary to explain the ectopic lignification and dark‐photomorphogenic phenotypes of the det3 mutant.
Salicylic acid regulates flowering time and links defence responses and reproductive development
Authors: Martínez Cristina , Pons Elsa , Prats Guillermo , León José 
Published: October 2010

SummaryFlowering relies on signaling networks that integrate endogenous and external cues. Normally, plants flower at a particular season, reflecting day length and/or temperature cues. However, plants can surpass this seasonal regulation and show precocious flowering under stress environmental conditions. Here, we show that UV‐C light stress activates the transition to flowering in Arabidopsis thaliana through salicylic acid (SA). Moreover, SA also regulates flowering time in non‐stressed plants, as SA‐deficient plants are late flowering. The regulation of flowering time by SA seems to involve the photoperiod and autonomous pathways, but it does not require the function of the flowering time genes CONSTANS (CO), FCA, or FLOWERING LOCUS C (FLC).
Two functionally different vacuoles for static and dynamic purposes in one plant mesophyll leaf cell
Authors: Epimashko Svetlana , Meckel Tobias , Fischer‐Schliebs Elke , Lüttge Ulrich , Thiel Gerhard 
Published: October 2010

SummaryIt is a common belief that plant mesophyll cells are occupied up to 95% by a single multipurpose vacuole. The common ice plant, Mesembryanthemum crystallinum L., however, requires two contrasting functions of the vacuole under salt stress. Large amounts of NaCl have to be sequestered permanently for osmotic purpose and for protecting the cytoplasm from NaCl toxicity. A dynamic exchange with the cytoplasm is required because photosynthesis proceeds under these conditions via the metabolic cycle of crassulacean acid metabolism (CAM). Nocturnally acquired CO2 must be kept as malate in the vacuole and re‐mobilized in the daytime. Here, we show that two large independent types of vacuoles with different transport properties meet the requirements for the contrasting functions within the same cell.
Cross‐species microarray transcript profiling reveals high constitutive expression of metal homeostasis genes in shoots of the zinc hyperaccumulator Arabidopsis halleri
Authors: Becher Martina , Talke Ina N. , Krall Leonard , Krämer Ute 
Published: October 2010

Summary Arabidopsis halleri ssp. halleri (accession Langelsheim) is a naturally selected zinc (Zn)‐ and cadmium‐tolerant Zn hyperaccumulator. This plant differs strikingly from its close relative A. thaliana by accumulating Zn specifically in above‐ground tissues. A. thaliana GeneChips were used in order to identify, on a transcriptome‐wide scale, genes with a potential involvement in cellular metal uptake or detoxification in the shoots of A. halleri. Compared to A. thaliana, transcript abundance of several genes was found and confirmed to be substantially higher in A. halleri after 4 days of exposure to low as well as high Zn concentrations in the hydroponic culture medium. The identified candidate genes encode proteins closely related to the following A. thaliana proteins: AtZIP6, a putative cellular Zn uptake system and member of the zinc‐regulated transporter (ZRT)‐iron regulated transporter (IRT)‐like protein (ZIP)‐family of metal transporters, the putative P‐type metal ATPase AtHMA3, the cation diffusion facilitator ZAT/AtCDF1, and the nicotianamine synthase AtNAS3. Heterologous expression in mutant strains of the yeast Saccharomyces cerevisiae suggested that AhHMA3, AhCDF1‐3, and AhNAS3 can function in cellular Zn detoxification. Our data indicate that, at the transcript level, the Zn tolerance strategy of A. halleri involves high constitutive expression of metal homeostasis genes in the shoots to accommodate higher basal levels of Zn accumulation, and possibly to prepare for sudden increases in Zn influx into shoot cells. Furthermore, profiling of metal homeostasis gene transcripts in shoot and root tissues by real‐time RT‐PCR indicated that A. halleri and A. thaliana respond differently to changes in plant Zn status.
Comparative microarray analysis ofArabidopsis thalianaandArabidopsis halleriroots identifies nicotianamine synthase, a ZIP transporter and other genes as potential metal hyperaccumulation factors
Authors: Weber Michael , Harada Emiko , Vess Christoph , Roepenack‐Lahaye Edda v. , Clemens Stephan 
Published: October 2010

SummaryThe hyperaccumulation of zinc (Zn) and cadmium (Cd) is a constitutive property of the metallophyteArabidopsis halleri. We therefore usedArabidopsisGeneChips to identify genes more active in roots ofA. hallerias compared toA. thalianaunder control conditions. The two genes showing highest expression inA. halleriroots relative toA. thalianaroots out of more than 8000 genes present on the chip encode a nicotianamine (NA) synthase and a putative Zn2+uptake system. The significantly higher activity of these and other genes involved in metal homeostasis under various growth conditions was confirmed by Northern and RT‐PCR analyses.A. halleriroots also show higher NA synthase protein levels. Furthermore, we developed a capillary liquid chromatography electrospray ionization quadrupole time‐of‐flight mass spectrometry (CapLC‐ESI‐QTOF‐MS)‐based NA analysis procedure and consistently found higher NA levels in roots ofA. halleri. Expression of a NA synthase in Zn2+‐hypersensitiveSchizosaccharomyces pombecells demonstrated that formation of NA can confer Zn2+tolerance. Taken together, these observations implicate NA in plant Zn homeostasis and NA synthase in the hyperaccumulation of Zn byA. halleri. Furthermore, the results show that comparative microarray analysis of closely related species can be a valuable tool for the elucidation of phenotypic differences between such species.
Neurodevelopmental outcome of very low birth weight babies admitted to a Malaysian nursery
Authors: Ho JJ , Amar HSS , Mohan AJ , Hon TH 
Published: October 2010

Objective: To examine the prevalence and pattern of neurodevelopmental handicap at 2 years of age in very low birth weight infants (VLBW) admitted in 1993 to a level 3 Malaysian nursery. Methods: All VLBW babies born in the hospital or referred for neonatal care during 1993 were enrolled prospectively in the study. At 2 years of age development was assessed using the Griffiths mental scales. Neurological, hearing and visual assessments were graded into five groups according to functional handicap. Control infants were randomly selected during attendance at a primary health care clinic. Results: One hundred and fifty VLBW infants were admitted and 82 (54.6%) survived to 2 years, of whom 77 (93.9%) were assessed. The mean General Quotient (GQ) on the Griffiths Scales was 94 (15.7) for the study group and 104 (8.3) for the 60 controls. For GQ, 21 (27.3%) of the study population were 1 or more SD below the mean (18 between 1 and 2 SD and 3 > 2 SD) compared with 1 (1.6%) of the controls who was 1–2 SD below the mean. Visual impairment occurred in 2 study infants and none of the controls. There was no hearing impairment in either group. Cerebral palsy occurred in 3 (1 mild and 2 moderate‐severe) of the study group and none of the controls. Functionally 18 (23.3%) of the study group had mild handicap, 1 (1.3%) moderate, 2 (2.5%) severe, 2 (2.5%) multiply severe and 54 (70.2%) were normal. Conclusion: Although survival was low, overall rates of functional handicap were similar to those reported in developed countries but the proportion with moderate or severe handicap was low.
Randomised clinical trial of a group parent education programme for Australian Indigenous families
Authors: Turner Karen MT , Richards Mary , Sanders Matthew R 
Published: October 2010

Aim:  Parenting programmes have been shown to improve children’s adjustment and reduce problem behaviour; however, little research has addressed outcomes for Indigenous families. The aim of this project was to assess the impact and cultural appropriateness of a parenting programme tailored for Indigenous families, an adaptation of the evidence‐based Group Triple P – Positive Parenting Program.Methods:  A repeated measures randomised group design methodology was used, comparing the intervention with a waitlist control condition pre‐ and post‐intervention, with a 6‐month follow‐up of the intervention group.Results:  Parents attending Group Triple P reported a significant decrease in rates of problem child behaviour and less reliance on some dysfunctional parenting practices following the intervention in comparison to waitlist families. The programme also led to greater movement from the clinical range to the non‐clinic range for mean child behaviour scores on all measures. Effects were primarily maintained at 6‐month follow‐up. Qualitative data showed generally positive responses to the programme resources, content and process. However, only a small number of waitlist families subsequently attended groups, signalling the importance of engaging families when they first make contact, helping families deal with competing demands, and offering flexible service delivery so families can resume contact when circumstances permit.Conclusions:  This study provides empirical support for the effectiveness and acceptability of a culturally tailored approach to Group Triple P conducted by Child Health and Indigenous Health workers in a community setting. The outcomes of this trial may be seen as a significant step in increasing appropriate service provision for Indigenous families and reducing barriers to accessing available services in the community.
Occurrence of subclinical post‐streptococcal glomerulonephritis in family contacts
Authors: Tasic V , Polenakovic M 
Published: October 2010

Objective:  There are few data in the published literature on the occurrence of subclinical post‐streptococcal glomerulonephritis. In order to estimate the incidence of subclinical disease, 75 families of index cases with sporadic clinical post‐streptococcal glomerulonephritis were screened for the presence of subclinical disease.Methods:  Three hundred and seventeen family contacts were investigated 1−7 days after the admission of the index cases. The diagnosis of subclinical disease was based on the presence of abnormal urinalysis, transitory hypocomplementaemia and increased antistreptolysin O titre.Results:  No cases of clinical/subclinical disease were detected among 147 parents. Abnormal urinalyses were found in 22.3% of sibling contacts. The incidence of nephritis among 170 siblings was 9.4% and the calculated ratio subclinical/clinical disease was 0.11. There were 16 siblings (9.4%) whose abnormal urinalyses could not be explained by appropriate tests; 11 of them had dysmorphic microhaematuria and significantly elevated antistreptolysin O titre.Conclusions:  Sibling contacts have increased risk for the development of clinical/subclinical post‐streptococcal glomerulonephritis compared with their parents. Sibling contacts with unexplained urinary abnormalities might have subclinical nephritis in evolution; their complement levels normalized before occurrence of nephritis in index cases.