bluuebunny/crossref_metadata_2025_split huggingface dataset:
Securing the Faint End of the Galaxy Luminosity Function
Authors: Jerjen Helmut , Tully Brent , Trentham Neil 
Published: December 2004

AbstractThe history of the formation of galaxies must leave an imprint in the properties of the mass function of collapsed objects and in its observational manifestation, the galaxy luminosity function. At present the faint end of the luminosity function is poorly known. Accurate knowledge of the luminosity function over the full range of galaxy clustering scales would provide serious constraints on both initial cosmological conditions and modulating astrophysical processes.Wide field imaging surveys with large ground-based telescopes now provide the capability to identify dwarf galaxy candidates to very faint levels (μR ≈ 26 mag arcsec–2), too low in surface brightness for spectroscopy (measuring redshifts) even with telescopes like Keck. Other means have to be explored to get distance information for these candidates in order to separate cluster members from back/foreground systems beyond doubt. On the quest to establish the properties (slope and possible turning point) of the the faint end of the galaxy luminosity function we are employing the surface brightness fluctuation (SBF) method to determine adequate distances, potentially resulting in the best definition ever of the luminosity function to MR ≈ –11 in the cluster and group environments.
COLCHICINE‐INDUCED ALTERATIONS IN COLONY DEVELOPMENT IN EUDORINA ELEGANS (VOLVOCALES, CHLOROPHYTA)1
Authors: Gottlieb Bruce , Goldstein Melvin E. 
Published: December 2004

ABSTRACTColonies of Eudorina elegans Ehrenberg were treated with a 0.2% colchicine solution for periods of up to 48 h, and a number of alterations were observed in dividing colonies. Nuclear alterations were observed after 20 min of treatment, due to the inhibition of spindle microtubule polymerization. This inhibition resulted in increased ploidy levels, and permanent diploid colonies were obtained. The inhibition of cytoplasmic microtubule polymerization resulted in a number of structural alterations including: unequal cytokinesis of plakeal cells, the partial or complete inhibition of cytokinesis (30 min treatment), production of “stellate” cells (90 min treatment), and the subsequent formation of extra‐cytoplasmic particles around the plakeal cells (3 h treatment). A possible cytoskeletal function of peripherally orient ed microtubules, and the role of the phycoplast microtubules is discussed. In addition, colchicine treatment caused an inhibition of inversion (60 min treatment), an increase in golgi‐associated vesicles, and an excessive production of colonial envelope material (3 h treatment). The latter resulted in the formation of flattened Gonium‐like colonies. The process of inversion is discussed in light of the above results. Chloroplast microtubules, however, were unaffected by colchicine treatment.
NUCLEOTIDE SEQUENCE HOMOLOGY OF SOME ALGAL RIBOSOMAL RNAs1
Authors: Soh Guat Lean , Kochert Gary 
Published: December 2004

ABSTRACTRadioactively labeled ribosomal RNA from seven species of algae was purified and hybridized to purified DNA from Chlamydomonas reinhardtii Dangeard (Chlorophyta). Delta Tm values for the heterologous RNA‐DNA duplexes were obtained by thermal dissociation; values ranged from 3.9 to 10.9 C. Organisms traditionally considered to be less closely related to C. reinhardtii showed the greatest delta Tm values. Ulothrix fimbriata Bold and Klebsormidium flaccidum (Kütz.) S., M. & Bl., although similar morphologically, showed very different delta Tm values and would not appear to be closely related by these criteria.
CHLORIDE UPTAKE BY ANACYSTIS NIDULANS (CYANOPHYCEAE)1
Authors: Craig Susan R. , Budd Kenneth 
Published: December 2004

ABSTRACT Anacystis nidulans (Richt.) Drouet & Daily (UTEX 625), grown in batch culture with 0.5% CO2 in air, was supplied with chloride labelled with 36Cl in light and dark. Uptake in light was stimulated relative to uptake in darkness. A single transport system for Cl− with an apparent Km for Cl− of 0.14 mM was identified. Chloride in the cells reached a maximum value after 30–50 min at 25 C. At this point the internal Cl− concentration was calculated to be 60‐fold the external (0.1 mM) in light and 37‐fold in darkness. DCMU (3‐[3,4‐dichlorophenyl]–1, 1‐dime‐thylurea), at concentrations which abolished photosynthetic O2 evolution did not inhibit Cl− uptake in light. Carbonyl cyanide m‐chlorophenyl hydrazone (CCCP), at uncoupling concentrations for photosynthesis and dark respiration, strongly inhibited Cl− uptake in light and darkness. N,N'‐dicyclohexyl carbodiimide (DCCD), an energy transfer inhibitor, inhibited light Cl− uptake more slowly than photosynthesis but had no effect on dark Cl− uptake. It is concluded that Cl− uptake in A. nidulans was active in light and darkness, and that ATP was the probable energy source for transport.
A MORPHOMETRIC STUDY OF LEAD AND COPPER EFFECTS ON DIATOMA TENUE VAR. ELONGATUM (BACILLARIOPHYTA)1
Authors: Sicko‐Goad Linda , Stoermer Eugene F. 
Published: December 2004

ABSTRACTPolyphosphate bodies containing lead were induced in laboratory cultures of Diatoma tenue var. elongatum Lyngb. by the addition of phosphorus and 0.05 μg‐atoms/l Pb to P deficient medium. Morphometric analysis of cells exposed to Pb showed a significant decrease in number of mitochondria with a concomitant increase in their volume and an increase in membranous organelles in the vacuole compared to phosphorus starved and phosphorus sufficient controls. Exposure of cultures to 0.08 μg‐atoms/l copper resulted in reduction of the number of polyphosphate bodies formed during luxury uptake but no other significant morphological changes in cellular organelles. Ecological implications of the interactions between nutrients and low level trace metal contamination are discussed.
CHLOROPHYLL a:b RATIOS IN MARINE PLANKTONIC ALGAE1
Authors: Wood A. Michelle 
Published: December 2004

ABSTRACTChlorophyll a:b ratios for Chlorella capsulata Guillard, Bold & MacEntee, Chlorosarcinopsis halophila Guillard, Bold,& MacEntee, Nannochloris atomus Butcher and Micromonas pusilla (Butcher) Manton & Parke were found to be 1.74, 2.46, 1.89, and 1.53, respectively. Compared to previously published values in marine planktonic algae, these ratios are similar to the average value (2.17, SD = 1.12) reported for 25 species in 15 genera. Both the new data and previously published data support the hypothesis that marine algae have lower chlorophyll a:b ratios than do other chlorophyll b containing plants.
ON THE TAXONOMY OF CALIFORNIA LAMINARIA (PHAEOPHYTA)1
Authors: Druehl Louis D. 
Published: December 2004

ABSTRACTIt is suggested that Laminaria setchellii Silva be retained as a species separate from L. dentigera Kjellman as there is no evidence suggesting they are conspecific. Further, L. saccharina (L.) Lamouroux and L. groenlandica Rosenvinge should also continue to be recognized as valid components of the California flora.
Xxth International Congress of Photogrammetry and Remote Sensing
Authors: Newby Paul R. T. , Woodsford Peter A. , Mills Jon P. , Holland David A. , Tompkinson William , Holmes Adrian J. , Robson Stuart , Aplin Paul , Buckley Simon J. , Mehner Henny 
Published: December 2004

AbstractThe XXth International Congress of Photogrammetry and Remote Sensing was held at the Istanbul Convention and Exhibition Centre (ICEC), Turkey, from 12th to 23rd July 2004. Reports are given on the Congress as a whole, including the General Assembly, some Technical Commission activities and the Congress Exhibition. Papers from the Congress are published in Volume XXXV of the International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences.
Photoperiod Affects Neuronal Nitric Oxide Synthase and Aggressive Behaviour in Male Siberian Hamsters (Phodopus sungorus)
Authors: Wen J. C. , Hotchkiss A. K. , Demas G. E. , Nelson R. J. 
Published: December 2004

AbstractMany nontropical animals display physiological and behavioural changes in response to seasonal environmental cues including photoperiod (day length). Male Siberian hamsters (Phodopus sungorus) housed in short photoperiod undergo testicular regression accompanied by reduced circulating testosterone and decreased reproductive behaviour. By contrast to the majority of small mammals studied, aggressive behaviour is elevated in short‐day Siberian hamsters when blood testosterone concentrations are not detectable. Because gonadal steroid hormones influence neuronal nitric oxide synthase (nNOS), and this enzyme has been implicated in aggressive behaviour, we hypothesized that nNOS expression would be decreased in short‐day male Siberian hamsters and negatively correlated with the display of territorial aggression. Adult male Siberian hamsters were individually housed in either long (LD 16 : 8 h) or short (LD 8 : 16 h) photoperiods for 10 weeks. Hamsters were assigned to one of two categories by assessing testicular volume and plasma testosterone values: (i) photoperiodic responsive (i.e. regressed testes and low testosterone concentrations) or (ii) photoperiodic nonresponsive (i.e. testes size and circulating testosterone concentrations equivalent to hamsters maintained in long days). At week 10, aggression was assessed using a resident–intruder test. Latency to initial attack, frequency of attacks and duration of total attacks were recorded during a 10‐min aggression trial. Brains were collected immediately after behavioural testing and stained for nNOS expression using immunohistochemistry. All short day‐housed hamsters were significantly more aggressive than long‐day animals, regardless of gonadal size or testosterone concentrations. Short‐day animals, both reproductively responsive and nonresponsive morphs, also had significantly less nNOS‐immunoreactive cells in the anterior and basolateral amygdaloid areas and paraventricular nuclei compared to long‐day hamsters. Together, these results suggest that seasonal aggression in male Siberian hamsters is regulated by photoperiod, through mechanisms that are likely independent from gonadal steroid hormones.
Analysis of the aliphatic monomer composition of polyesters associated with Arabidopsis epidermis: occurrence of octadeca‐cis‐6, cis‐9‐diene‐1,18‐dioate as the major component
Authors: Bonaventure Gustavo , Beisson Frédéric , Ohlrogge John , Pollard Mike 
Published: December 2004

SummaryAlthough the surface waxes from Arabidopsis thaliana leaves and stems have been thoroughly characterized, the monomer composition of the polyesters of the cuticular membrane has not been analyzed. Delipidated Arabidopsis leaves or stems, when depolymerized under conditions to cleave polyesters, produced typical ω–hydroxy fatty acid cutin monomers such as 16‐hydroxy‐palmitate, 10,16‐dihydroxy‐palmitate and 18‐hydroxy‐9,10‐epoxy‐stearate. However, the major monomer was octadeca‐cis‐6, cis‐9‐diene‐1,18‐dioate, with lesser amounts of octadec‐cis‐9‐ene‐1,18‐dioate and hexadeca‐1,16‐dioate. These dicarboxylates were found predominantly in epidermal peels from Arabidopsis stems and are therefore likely to be associated with the cuticular membrane. They were also found in analyses of canola leaves but were absent in tomato and apple fruit cutins. In the fad2‐1 mutant line of Arabidopsis, which has reduced levels of linoleate and linolenate and elevated oleate in cytosolic phospholipids, the amount of octadeca‐cis‐6, cis‐9‐diene‐1,18‐dioate was 50% reduced, with a concomitant increase in octadec‐cis‐9‐ene‐1,18‐dioate. In a fatb‐ko line of Arabidopsis, where the availability of cytosolic palmitate is impaired, there was an 80% loss of C16 monomers and a compensating increase in C18 monomers. The presence of substantial amounts of dicarboxylates in cuticular membranes is unexpected. High amounts of aliphatic dicarboxylates are usually considered as an indicator of suberin, and are reported only as very minor components of cutin. The high level of polyunsaturation is also unusual in cuticles; saturated fatty acid monomers usually predominate, with lesser amounts of monounsaturates. These novel findings for Arabidopsis demonstrate that a broad range of monomer compositions are possible for polyesters of the epidermis.
Comparison of TRY and the closely related At1g01380 gene in controlling Arabidopsis trichome patterning
Authors: Esch Jeffrey J. , Chen Margaret A. , Hillestad Matthew , David Marks M. 
Published: December 2004

SummaryA screen of activation‐tagged Arabidopsis lines resulted in the identification of At1g01380, which encodes a small R3 single repeat MYB gene, as a negative regulator of trichome initiation. Plants that overexpress this gene have fewer trichomes. The gene is closely related to the previously identified negative regulator TRY, and has a similar pattern of expression as TRY in developing leaves. As previously shown for TRY, At1g01380 protein can inhibit the interaction between the positive trichome regulators GL1 and GL3, and likely limits trichome initiation via this inhibition. While TRY and At1g01380 are closely related, they are not completely functionally equivalent. When placed under the transcriptional control of the TRY promoter, At1g01380 can only partially rescue the try mutant. Interestingly, Atg01380 is highly expressed in gl3‐sst trichomes, while TRY expression is greatly reduced. The mutation in gl3‐sst causes a reduced interaction between the GL1 and GL3 proteins and results in fewer leaf trichomes that develop in clusters. The differential expression of TRY and At1g01380 in this mutant can be used to explain how its altered trichome pattern in gl2‐sst is generated.
Arabidopsis glucosyltransferase UGT74B1 functions in glucosinolate biosynthesis and auxin homeostasis
Authors: Douglas Grubb C. , Zipp Brandon J. , Ludwig‐Müller Jutta , Masuno Makoto N. , Molinski Tadeusz F. , Abel Steffen 
Published: December 2004

SummaryGlucosinolates are a class of secondary metabolites with important roles in plant defense and human nutrition. Here, we characterize a putative UDP‐glucose:thiohydroximate S‐glucosyltransferase, UGT74B1, to determine its role in the Arabidopsis glucosinolate pathway. Biochemical analyses demonstrate that recombinant UGT74B1 specifically glucosylates the thiohydroximate functional group. Low Km values for phenylacetothiohydroximic acid (approximately 6 μm) and UDP‐glucose (approximately 50 μm) strongly suggest that thiohydroximates are in vivo substrates of UGT74B1. Insertional loss‐of‐function ugt74b1 mutants exhibit significantly decreased, but not abolished, glucosinolate accumulation. In addition, ugt74b1 mutants display phenotypes reminiscent of auxin overproduction, such as epinastic cotyledons, elongated hypocotyls in light‐grown plants, excess adventitious rooting and incomplete leaf vascularization. Indeed, during early plant development, mutant ugt74b1 seedlings accumulate nearly threefold more indole‐3‐acetic acid than the wild type. Other phenotypes, however, such as chlorosis along the leaf veins, are likely caused by thiohydroximate toxicity. Analysis of UGT74B1 promoter activity during plant development reveals expression patterns consistent with glucosinolate metabolism and induction by auxin treatment. The results are discussed in the context of known mutations in glucosinolate pathway genes and their effects on auxin homeostasis. Taken together, our work provides complementary in vitro and in vivo evidence for a primary role of UGT74B1 in glucosinolate biosynthesis.
Mutations in PMR5 result in powdery mildew resistance and altered cell wall composition
Authors: Vogel John P. , Raab Theodore K. , Somerville Chris R. , Somerville Shauna C. 
Published: December 2004

SummaryPowdery mildews and other obligate biotrophic pathogens are highly adapted to their hosts and often show limited host ranges. One facet of such host specialization is likely to be penetration of the host cell wall, a major barrier to infection. A mutation in the pmr5 gene rendered Arabidopsis resistant to the powdery mildew species Erysiphe cichoracearum and Erysiphe orontii, but not to the unrelated pathogens Pseudomonas syringae or Peronospora parasitica. PMR5 belongs to a large family of plant‐specific genes of unknown function. pmr5‐mediated resistance did not require signaling through either the salicylic acid or jasmonic acid/ethylene defense pathways, suggesting resistance in this mutant may be due either to the loss of a susceptibility factor or to the activation of a novel form of defense. Based on Fourier transform infrared analysis, the pmr5 cell walls were enriched in pectin and exhibited a reduced degree of pectin modification relative to wild‐type cell walls. In addition, the mutant had smaller cells, suggesting a defect in cell expansion. A double mutant with pmr6 (defective in a glycosylphosphatidylinositol‐anchored pectate lyase‐like gene) exhibited a strong increase in total uronic acid content and a more severe reduction in size, relative to the single mutants, suggesting that the two genes affect pectin composition, either directly or indirectly, via different mechanisms. These two mutants highlight the importance of the host cell wall in plant–microbe interactions.
Loss of TIP1;1 aquaporin in Arabidopsis leads to cell and plant death
Authors: Ma Shisong , Quist Tanya M. , Ulanov Alexander , Joly Robert , Bohnert Hans J. 
Published: December 2004

SummaryArabidopsis TIP1;1 (γTIP) is a member of the tonoplast family of aquaporins (AQP). Using RNA interference (RNAi) we reduced TIP1;1 to different extent in various lines. When most severely affected, miniature plants died, a phenotype partially complemented by the TIP1;1 homolog McMIP‐F. Less severely affected lines produced small plants, early senescence, and showed lesion formation. The relative water content in TIP1;1 RNAi plants was not significantly affected. Global expression profiling suggested a disturbance in carbon metabolism in RNAi lines with upregulated transcripts for functions in carbon acquisition and respiration, vesicle transport, signaling and transcription, and radical oxygen stress. Metabolite profiles showed low glucose, fructose, inositol, and threonic, succinic, fumaric, and malic acids, but sucrose levels were similar to WT. Increased amounts were found for raffinose and several unknown compounds. TIP1;1 RNAi plants also contained high starch and apoplastic carbohydrate increased. A GFP‐TIP1;1 fusion protein indicated tonoplast location in spongy mesophyll cells, and high signal intensity in palisade mesophyll associated with vesicles near plastids. Signals in vascular tissues were strongest not only in vesicle‐like structures but also outlined large vacuoles. Compromised routing of carbohydrate and lack of sucrose provision for cell‐autonomous functions seems to characterize this RNAi phenotype. We suggest a function for TIP1;1 in vesicle‐based metabolite routing through or between pre‐vacuolar compartments and the central vacuole. Phenotype and expression characteristics support a view of TIP1;1 functioning as a marker for vesicles that are targeted to the central vacuole.
Endogenous salicylic acid protects rice plants from oxidative damage caused by aging as well as biotic and abiotic stress
Authors: Yang Yinong , Qi Min , Mei Chuansheng 
Published: December 2004

SummarySalicylic acid (SA) is a key endogenous signal that mediates defense gene expression and disease resistance in many dicotyledonous species. In contrast to tobacco and Arabidopsis, which contain low basal levels of SA, rice has two orders of magnitude higher levels of SA and appears to be insensitive to exogenous SA treatment. To determine the role of SA in rice plants, we have generated SA‐deficient transgenic rice by expressing the bacterial salicylate hydroxylase that degrades SA. Depletion of high levels of endogenous SA in transgenic rice does not measurably affect defense gene expression, but reduces the plant's capacity to detoxify reactive oxygen intermediates (ROI). SA‐deficient transgenic rice contains elevated levels of superoxide and H2O2, and exhibits spontaneous lesion formation in an age‐ and light‐dependent manner. Exogenous application of SA analog benzothiadiazole complements SA deficiency and suppresses ROI levels and lesion formation. Although an increase of conjugated catechol was detected in SA‐deficient rice, catechol does not appear to significantly affect ROI levels based on the endogenous catechol data and exogenous catechol treatment. When infected with the blast fungus (Magnaporthe grisea), SA‐deficient rice exhibits increased susceptibility to oxidative bursts elicited by avirulent isolates. Furthermore, SA‐deficient rice is hyperresponsive to oxidative damage caused by paraquat treatment. Taken together, our results strongly suggest that SA plays an important role to modulate redox balance and protect rice plants from oxidative stress.
Gene shuffling‐generated and natural variants of the tomato resistance gene Cf‐9 exhibit different auto‐necrosis‐inducing activities in Nicotiana species
Authors: Wulff Brande B.H. , Kruijt Marco , Collins Peter L. , Thomas Colwyn M. , Ludwig Andrea A. , De Wit Pierre J.G.M. , Jones Jonathan D.G. 
Published: December 2004

SummaryTomato Cf genes encode membrane‐bound proteins with extracellular leucine‐rich repeats, and confer resistance to the fungal tomato pathogen Cladosporium fulvum, and a hypersensitive response (HR) to C. fulvum‐derived race‐specific elicitors. Several Cf genes, including Cf‐4 and Cf‐9, are members of the highly homologous Hcr9 (homologues of C. fulvumresistance gene Cf‐9) gene family. Hcr9s evolve mainly by sequence exchange between paralogues, by which novel Cf genes may be generated. To mimic this aspect of natural evolution, we generated chimeras between multiple Hcr9s in vitro by gene shuffling. The shufflants were tested for novel specificities by transient expression in Nicotiana benthamiana. Many shufflants induced an HR in the absence of fungal elicitors and were designated auto‐activators. We also identified two natural Hcr9 auto‐activators in the wild tomato species Lycopersicon peruvianum, which induced an HR upon expression in N. benthamiana. The Hcr9 auto‐activators exhibit different auto‐necrosis‐inducing specificities in five selected species of the Nicotiana genus, and they were shown to function in the same signalling pathway as Cf‐9. Auto‐activating alleles of nucleotide binding site–leucine‐rich repeat genes and the protein kinase Pto were previously described. The auto‐activators described here, belonging to the Cf‐like structural class of resistance genes, shed light on this important phenotype and may be used as tools to unravel the mechanisms by which this class of resistance proteins function.
A retrospective study comparing the histopathological features and response to treatment in two canine nasal dermatoses, DLE and MCP
Authors: WIEMELT S. P. , GOLDSCHMIDT M. H. , GREEK J. S. , JEFFERS J. G. , WIEMELT A. P. , MAULDIN E. A. 
Published: December 2004

Abstract  Canine discoid lupus erythematosus (DLE) and mucocutaneous pyoderma (MCP) have overlapping clinical and histopathological changes, often making diagnosis difficult. Histopathological features of 27 nasal planum biopsies were scored to determine whether DLE and MCP were histopathologically distinguishable. Long‐term follow‐up, enabling assessment of clinical diagnoses, was available on 15 cases; 11/15 cases were immunomodulatory responsive (ImR) and 4/15 were antibiotic responsive (AbR). Clinical diagnosis, determined by response to treatment for 15/27 cases, was not predictable based on scoring of histopathological features. Distinct histopathological patterns were observed: 2/11 ImR cases had a lymphocyte‐rich interface dermatitis. All other cases had the same histopathological changes: a band‐like diffuse superficial plasmacytic to lymphoplasmacytic dermatitis ± focal basal cell damage, but different clinical diagnoses (4/4 AbR, 9/11 ImR). German shepherd dogs/crosses were over‐represented (44.4% of the cases) and tended to have more multifocal lesions (41.7% vs. 26.7% of all other breeds). Longer duration of disease was associated with a preponderance of plasmacytic infiltrate (P = 0.026).