bluuebunny/crossref_metadata_2025_split huggingface dataset:
A mathematical model of the regulation of the G1 phase of Rb +/+ and Rb —/— mouse embryonic fibroblasts and an osteosarcoma cell line
Authors: Obeyesekere M. N. , Knudsen E. S. , Wang J. Y. J. , Zimmerman S. O. 
Published: May 2008

AbstractA mathematical model integrating the roles of cyclin D, cdk4, cyclin E, cdk2, E2F and RB in control of the G1 phase of the cell cycle is described. Experimental results described with murine embryo fibroblasts (MEFs), either Rb +/+ or Rb —/—, and with the RB‐deficient osteosarcoma cell line, Saos‐2, served as the basis for the formulation of this mathematical model. A model employing the known interactions of these six proteins does not reproduce the experimental observations described in the MEFs. The appropriate modelling of G1 requires the inclusion of a sensing mechanism which adjusts the activity of cyclin E/cdk2 in response to both RB concentration and growth factors. Incorporation of this sensing mechanism into the model allows it to reproduce most of the experimental results observed in Saos‐2 cells, Rb —/— MEFS, and Rb +/+ MEFs. The model also makes specific predictions which have not been tested experimentally.
Modulation of the cell kinetics of pig skin by the topical application of evening primrose oil or Lioxasol
Authors: Morris G. M. , Hopewell J. W. , Harold M. , Ross G. A. , Nadejina N. M. , Gusev I. , Flockhart I. 
Published: May 2008

AbstractThe daily topical application of two compounds, a cream containing 10% evening primrose oil (EPO) and Lioxasol (a compound used clinically to treat radiation burns), resulted in increased cell proliferative activity in the skin of female Large White pigs. The effect was most pronounced in the case of the EPO based cream, and was comparable in magnitude with that observed in a previous study on pig skin using orally administered EPO.There was an increase in the size of the rete pegs in the epidermis by 6 weeks after the start of application of the EPO cream. However, this did not translate into an increase in the total thickness of the viable epidermis (excluding the stratum corneum) due to a reduction in the density of rete pegs, from 2 weeks after treatment. Lioxasol had no overall effect on the size of the rete pegs. The labelling index (LI) of cells in the basal layer of the epidermis of pigs receiving a daily topical application of EPO increased progressively with time from the start of application. The LI was maximal (17.9 ± 2.4%) at the end of the observation period (8 weeks) at which time it was a factor of ∼ 2 higher than in the basal layer prior to treatment. A considerably less marked increase in the LI of the basal layer was seen after the application of Lioxasol. The overall increase was ∼ 20%, relative to the LI in the untreated epidermis.Labelled cell nuclei were also counted in the papillary dermis. After the application of the EPO cream, no significant increase in the number of labelled cells was observed until week 8, at which time values were approximately twice those in untreated skin. In Lioxasol treated skin the effect on the numbers of labelled cells in the papillary dermis was more immediate, with a ∼ 60% increase at 2 weeks. This enhanced level of labelling was maintained until the end of the observation period of 10 weeks. Studies on the cell kinetics of the skin using the alcohol component of the Lioxasol preparation suggested that alcohol rather than Lioxasol was the most signifiant ingredient. It was concluded that the EPO cream merited further evaluation as a potential modulator of skin response to ionizing radiation.
Demonstration of an Na+/H+ exchanger in mouse keratinocytes measured by the novel pH‐sensitive fluorochrome SNARF‐calcein
Authors: van Hooijdonk C. A. E. M. , Colbers R. M. L. , Piek J. , van Erp P. E. J. 
Published: May 2008

AbstractIn many cell types cytoplasmic alkalization is an early marker for cell activation. An amiloride‐sensitive Na+/H+ exchanger is an important regulator of this process. However, in keratinocytes the existence of a Na+/H+ exchanger nor a proliferation‐associated increase in intracellular pH (pHi) has been demonstrated.The aim of this study was to investigate whether or not keratinocytes, derived from the BALB/MK cell line, contain a Na+/H+ exchanger and whether cytoplasmic alkalization is proliferation‐associated in these cells. This mouse keratinocyte cell line can easily be switched between a proliferative and a quiescent state under defined culture conditions. The novel pH‐sensitive dye seminaphthorhodafluor (SNARF)‐calcein proved to be very suitable for flow cytometric pHi measurements in BALB/MK cells. Initial measurements of the pHi using a cocktail of the established fluorochromes 2′,7′‐bis(carboxyethyl)‐5,6‐carboxyfluorescein (BCECF) and SNARF‐1 failed because of the differential uptake and binding kinetics of these pH‐sensitive dyes.Using SNARF‐calcein we were able to show proliferation to be associated with increased pHi. However, culture conditions were critical for these measurements. Our data indicate that the Na+/H+ exchanger is involved in this process, since acid load and pHi‐recovery experiments showed the alkalization to be amiloride‐sensitive.
The Hypersensitive Reaction in Tobacco Leaf Tissue infiltrated with Pseudomonas pisi 4. Scanning Electron Microscope Studies on fractured Leaf Tissue
Authors: Sigee D. C. , Al‐Issa A. N. 
Published: May 2008

AbstractLeaves of tobacco infiltrated with Pseudomonas pisi were fractured at various times during the course of the hypersensitive reaction to expose cell surfaces within the tissue and mesophyll cell contents. Scanning electron microscopy of cross‐fractured mesophyll cells did not reveal any gross change in internal structure during the reaction induction period (0—2 h), but breakdown of tonoplast and collapse of chloroplasts commenced at about 5 h, during the latent period. Death of the mesophyll cells was followed by condensation of cell contents, and pronounced stretching of cell walls, due to desiccation and shrinkage.Between 0—6 h after infiltration, bacteria were largely confined to cell junctions, frequently within droplets. With collapse of the host cells and release of cell fluid, numbers of bacteria increased considerably (many dividing cells), and there was a shift of bacterial distribution to the whole mesophyll cell surface. The progressive desiccation that occurred between 10—20 h prevented further bacterial increase, but numbers of bacteria remained stable. Death of bacteria commenced at about 15 h, and was accompanied by the formation of numerous surface protrusions, which detached and deposited over the whole mesophyll surface.
Mechanism of Genome Expression in a Single‐stranded RNA Virus from the Cultivated Mushroom [Agaricus bisporus (Lange) Imbach]
Authors: Tavantzis M. , Romaine C. P. , Smith S. H. 
Published: May 2008

AbstractThe single‐stranded RNA genome of a bacilliform virus from the common cultivated mushroom, Agaricus bisporus, was translated in an in vitro rabbit reticulocyte system. Optimal conditions for translation of mushroom bacilliform virus (MBV) RNA were 2.5 mM Mg2+, 70 mM K+, pH 7.2, and 60μg/ml RNA. Gel electrophoretic analysis showed that MBV RNA directs the synthesis of two major polypeptides of MW 77,000 and 37,000 and possibly several minor polypeptides (MW 21,000—28,000). An RNA polymerase activity could not be detected in purified virus preparations. The findings support the notion that the MBV genome functions directly as messenger for protein synthesis and further establishes the closer similarity between MBV and viruses of higher plants than mycoviruses.
Elektronenmikroskopische Untersuchungen des Gerstenmehltaus (Erysiphe graminis DC f. sp. hordei Marchal) nach Resistenzinduktion mit mikrobiellen Stoffwechselprodukten
Authors: Ebrahim‐Nesbat F. , Balder H. , Schönbeck F. 
Published: May 2008

Abstract Electron microscopical studies on Mildew of Barley (Erysiphe graminis DC f. sp. hordei Marchal) after induced Resistance with Products of Microbial Metabolism Ultrastructural studies of the infection progress of barley by Erysiphe graminis after induction of resistance with products of microbial metabolism showed that pathogen development was affected through inducer activated defence mechanisms. The formation of papillae‐like structures and an accumulation of electron dense material below the host cell wall at the penetration site appeared to be associated with reduced penetration. The haustoria were also altered in the extrahaustorial membrane and electron dense material accumulated at the cell wall of haustorial body and neck, thus apparently impairing efficient functioning and allowing only limited growth of the pathogen.
Cellulolytic Activity of Botrytis cinerea in vitro and in vivo
Authors: Verhoeff K. , Lihm J. I. , Scheffer R. J. , Surya I. 
Published: May 2008

AbstractExperiments were carried out to determine whether stepwise breakdown of native cellulose is carried out by B. cinereain vitro and in vivo. Protein fractions were obtained from ungerminated conidia, from culture filtrates 24, 48 and 96 h after inoculation with conidia, and from culture filtrates of 12 day‐old cultures growing on cotton wool as the carbon source. In addition, petioles and fruits of tomato plants were inoculated and the protein fraction of the colonized tissues were tested. Using filter paper, carboxymethylcellulose and cellobiose as substrates, all fraction showed c1, glucanase and cellobiase activity respectively.
Foliar Spray of Urea and Rhizosphere Microflora of Corn (Zea mays L.)
Authors: Annapurna Y. , Rao P. Raghuveer 
Published: May 2008

AbstractFoliar application of urea to corn seedlings resulted in the preferential stimulation of gram negative bacteria with consequent reduction in fungal and actinomycete flora in the rhizosphere. The significance of this finding is briefly discussed.
Association of Tobacco Ringspot Virus with a Union Incompatibility of Apple
Authors: Lana Allan Femi , Peterson J. F. , Rouselle G. L. , Vrain T. C. 
Published: May 2008

AbstractA virus‐like disease of apple was observed for the first time in Canada in 1974 in a three year old planting. The disease was characterised by stem pitting, necrosis and breaking or separation of scion/rootstock at the graft union. Foliage was sparse and leaves were chlorotic and diffusely mottled. Using both frozen and freshly harvested leaves of infected apple trees from rootstock suckers as inoculum, a virus was transmitted to herbaceous indicator hosts. Based on host range symptoms, serology and electron microscopy, this virus was identified as tobacco ringspot virus. Initial counts of nematodes in the rhizophere of apple trees affected with union necrosis showed high densities of Xiphinema americanum Cobb., a known vector of nepoviruses. Reports of similar symptoms have indicated that the disease, apple union necrosis and decline was associated with the recovery of tobacco ringspot virus from infected rootstocks. This is the first report associating a union incompatibility condition of apple and tobacco ringspot virus.
Some Properties of Cucumber Fruit Streak Virus
Authors: Gallitelli D. , Vovlas C. , Avgelis A. 
Published: May 2008

AbstractAn isometric virus c. 30 nm in diameter with a single RNA species (mol.wt 1.45 × 106) isolated from cucumber plants from the island of Crete (Greece) is described under the name of cucumber fruit streak virus (CFSV). The most evident symptom on naturally infected plants consisted of longitudinal chlorotic streak of the fruits. In glasshouse, the virus was soil‐transmitted to C. sativus, and, mechanically, to a wide range of herbaceous hosts, most of which were infected only locally.Purified virus preparations sedimented as a single component with sedimentation coefficient of 132S. At equilibrium these preparations were homogeneous in CsCl gradients but formed two bands in Cs2SO4 gradients. Virus particles were stabilized by forces involving divalent cations, pH‐dependent bonds and salt links between protein and RNA. Although some of the properties of CFSV are similar to those of other small spherical viruses with single RNA species there are differences which do not allow for the assignment of the virus to any of established taxonomic group of plant viruses.
Recovery of Pseudocercosporella herpotrichoides Spores from Rain‐Splash Samples
Authors: Fitt B. D. L. , Bainbridge A. 
Published: May 2008

AbstractMethods for recovery of P. herpotrichoides spores from rain‐splash were tested, initially with pure spore suspensions and then with field samples. Provided surfactant was added and samples were processed immediately, centrifugation gave good recovery or spores from field samples which contained few soil particles. Foam‐flotation, glycerol and sucrose methods for separation of spores from soil particles were not satisfactory for P. herpotrichoides spores. A paraffin oil method proved to be the most reliable because it gave good recovery of P. herpotrichoides spores from field samples containing many soil particles.
Plant Viruses Affecting Tomatoes in Jordan. Identification and Prevalence
Authors: Al‐Musa A. , Mansour A. 
Published: May 2008

AbstractA survey was conducted during the period 1979–1982 to identify viruses affecting tomatoes in the Jordan Valley. Results indicated the rare occurrence of mosaic diseases caused by tobacco mosaic virus, cucumber mosaic virus, or potato virus Y. However, tomato yellow leaf curl virus was predominant.
Life Cycle of Botryodiplodia theobromae, a Soft Rot Pathogen of Yam
Authors: Ogundana S. K. 
Published: May 2008

Abstract Botryodiplodia theobromae Pat. forms chlamydospores and specialised hyphae in diseased yam tissues in which condition it tides over unfavourable periods. With favourable conditions the chlamydospores germinate and the specialised hyphae formed serve as sources of infection to new hosts and infect through wounds. Germination tubes infect by means of terminal appressoria, and nutrition within the host is effected by production of haustoria.
Fungitoxicity of Some Higher Plants with Special Reference to the Synergistic Activity Amongst some Volatile Fungitoxicants
Authors: Pandey D. K. , Chandra H. , Tripathi N. N. , Dixit S. N. 
Published: May 2008

AbstractDuring screening of the leaves of 25 plant species for their volatile toxicity against the test pathogen Fusarium lateritium f.sp.cajani, Aegle marmelos (Ae), Citrus aurantifolia (Ci) and Mentha arvensis var. piperascens (Me) exhibited strong toxicity inhibiting the mycelial growth completely. The active volatile constituents from each plant were isolated in the form of essential oil and the fungitoxicity of each oil was tested separately. The Aegle oil was found fungistatic while Citrus and Mentha oils were fungicidal in nature. Three oil combination (1:1 v/v) viz., Ae‐Ci, Ae‐Me and Ci‐Me were made and their fungitoxicity was tested. The oil combinations were found to be more fungitosic than the individual oils, which were fungistatic in nature. The Ci‐Me combination exhibited a broad fungitoxic spectrum while the other two Ae‐Ci and Ae‐Me possessed a narrow range of toxicity. The oils were found to have no toxic effect on seed germination, seedling growth (root and shoot length), and general morphology of the host plant(Cajanus cajan).
A Role for Pectinase and Protease Inhibitors in Fungal Rot Development in Tomato Fruits
Authors: Brown A. E. , Adikaram N. K. B. 
Published: May 2008

Abstract B. cinerea and C. atramentarium rotted wound‐inoculated green tomato fruits and wounded or intact ripe fruits while G. cingulata developed rots only in ripe fruits. Pectic en‐zymes were extracted from the fruit tissue rotted by B. cinerea and C. atramentarium but no pectic enzymes attributable to the fungus were detected in ripe fruits rotted by G. cingulata. G. cingulata produced endo‐PG and endo‐PL in vitro, C. atramentarium produced endo‐PL in vitro and in vivo and B. cinerea produced exo‐PG in vitro and in green fruits but endo‐PG and endo‐PL in ripe fruits. Well ripened tomato fruits contained high levels of endogenous PG. All three fungi produced proteolytic enzymes in vitro and in vivo. Proteases produced by G. cingulata and C. atramentarium had optimum activity at pH 9 to 10 and were not trypsin‐like or chymotrypsin‐like in nature. Protease produced by B. cinerea had optimum activity at pH 7 and showed both trypsin and chymotrypsin‐like activity.Proteins extracted from the cell walls of tomato fruits inhibited both the endo‐PG and endo‐PL produced by G. cingulata and the endo‐PL produced by B. cinerea but did not in‐hibit the activity of PGs produced by B. cinerea, the endo‐PL produced by C. atramentarium or the endogenous PG from tomato fruits.The cell wall proteins also contained trypsin and chymotrypsin inhibitor activity which inhibited 70 % of the activity of the protease produced by B. cinerea, but had little effect on the proteases produced by G. cingulata, C. atramentarium or the tomato endogenous protease.Enzymes produced in vitro by G. cingulata macerated green tomato tissue more slowly than enzymes produced in vitro by C. atramentarium and B. cinerea and the rate of mation was further reduced in the presence of added cell wall proteins. Excess inhibitor of the little effect on the rate of maceration by the enzymes produced by C. atramentarium of the cinerea.
Membrane Permeability of Conidia of Bipolaris oryzae
Authors: Nanda H. P. , Gangopadhyay S. 
Published: May 2008

AbstractGerminability of the conidia of B. oryzae, after an efflux of substances — both electrolytes and non‐electrolytes — was tested in sterilized solutions of plasmolytica and osmotica, ranging from molarity to 10−12 M. Maximum percent germination was recorded at 10−8 M concentration regardless of the exogenous supplement in the order KCl >D‐glucose >Mannitol >NaCl. Germination was very poor or non‐existent in other, higher or lower molarities tested except at 10−7 M wíth c. 50% germination. In nature the conidia, though nutrient independent, are subject to leaching and likely to lose viability; hence the possible role of the proper osmoticum, basing on the observed fact, in maintenance of membrane equilibrium and germinability of the leached conidia has been discussed.
A Messenger RNA for Tobacco Mosaic Virus Coat Protein in Infected Tobacco Mesophyll Protoplasts
Authors: Ogawa M. , Sakai F. , Takebe I. 
Published: May 2008

AbstractThe low molecular weight tobacco mosaic virus (TMV)‐specific RNA component (LMC) was demonstrated in tobacco mesophyll protoplasts by polyacrylamide gel electrophoresis of 14C‐uridine‐labelled RNA from infected protoplasts.Free and membrane‐bound polysomes were isolated from infected protoplasts, and RNA extracted from them was analyzed. TMV‐specific RNA species including full‐length viral RNA, its replicative intermediate, and LMC were found in both free and membrane‐bound polysomes, but were present in free polysomes in much larger amounts. In particular, as much as 37 % of total LMC in protoplasts was found in free polysomes. Fractionation of polysomes by sedimentation in sucrose gradients showed that LMC is associated with small‐sized polysomes (mono‐ to tetrasomes). Polysomes of this size class produced viral coat protein in a cell‐free protein synthesizing system from rabbit reticulocytes. On the other hand, full‐length TMV‐RNA was associated predominantly with larger polysomes which produced in the cell‐free system TMV‐specific high molecular weight polypeptides but no coat protein. These results indicated that LMC, a subgenomic RNA of TMV, in fact functions in vivo as messenger RNA for viral coat protein, as has been postulated on the basis of in vitro studies.
Studies on the Host Range of the Hyperparasite Aphanocladium album
Authors: Koç N. K. , Défago G. 
Published: May 2008

AbstractThe uredospores of the 14 rust species tested and an Ascochyta, sp. were heavily parasitized by A. album. The teliospores of 3 Ustilaginales species were slightly parasitized. Some other important plant parasites were inhibited at distance, some others did not show any damage.
The Effects of Aspirin and Polyacrylic Acid on the Multiplication and Spread of TMV in Different Cultivars of Tobacco with and without the N‐gene
Authors: White R. F. , Antoniw J. F. , Carr J. P. , Woods R. D. 
Published: May 2008

AbstractAspirin treatment of leaves of Nicotiana tabacum cv. Samsun at 20°C induced PR‐proteins and reduced the amount of tobacco mosaic virus (TMV) accumulated 7 days after inoculation. However, at 32°C both the amount of PR‐proteins induced and the reduction of TMV accumulated were less. Polyacrylic acid did not induce PR‐proteins, and caused little or no reduction in the amount of TMV accumulated at 20°C. In cv. Samsun NN at 32°C. aspirin induced the PR‐proteins and reduced the spread of TMV to surrounding tissue as treasured by the size of lesions produced on subsequent transfer to 20°C. Polyacrylic acid did not induce PR‐proteins in Samsun NN and had no effect on the spread of TMV. In cv. Xanthi‐ne, at 32°C aspirin and polyacrylic acid induced PR‐proteins and reduced the spread of TMV. At 35°C, polyacrylic acid induced little or no PR‐proteins and did not affect the spread of TMV.
Physical and Chemical Properties of Potato Aucuba Mosaic Virus and its Coat Protein
Authors: Artyukova E. V. , Krylov A. V. 
Published: May 2008

AbstractSome properties of potato aucuba mosaic virus (PAMV) were studied. PAMV virions have a buoyant density in CsCl of 1.315 g/cm3 and RNA content of 5.06 ± 0.1 %.Limited proteolysis of the PAMV capsid protein at N‐termini has been found in the process of virus isolation and storage. The race of protein degradation was considerably decreased by the presence of phenylmethyl sulphonylfluoride — a protease inhibitor — in resuspending buffer. Molecular weight estimates were 27,480 ± 319 for native PAMV protein and 24,113 ± 129 and 21,634 ± 124 for main breakdown products. Amino acid composition of the native PAMV protein seems to be very similar to that of native PVX protein and differs only in threonine, leucine, histidine, tyrosine and methyonine.All studied properties of PAMV and its protein confirm the belonging of PAMV to the potexvirus group.
Observation of Potato Virus X in Tobacco Mosaic Virus (TMV)‐ Induced Local Lesions and Surrounding Zones in Leaves of Datura stramonium L. in Mixed Infection
Authors: Reunov A. V. , Lega S. N. 
Published: May 2008

AbstractIn mixed infection by Tobacco Mosaic Virus (TMV) and Potato Virus X (PVX) of leaves of Datura stramonium L., PVX particles were observed in the developing local lesions in both the central part and on the periphery, in addition to TMV. PVX virions were found either separately or together with TMV. Sometimes in local lesions mainly in their periphery, PVX‐specific laminar inclusion components were observed and, in certain cases, cylindrical bodies about 120—140 nm in diameter.In 2 mm surrounding zones from the edge of the lesions, TMV particles were not observed. However, in the majority of cells of these zones, PVX intensively accumulated, often forming large masses. In some cases, we observed parts of cells with relatively small amounts of dispersed PVX particles, associated with laminar inclusion bodies. In cell areas with large accumulations of PVX, laminar inclusions were not found.