bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro systems for studying the interaction of root-knot nematode with grapevine
Authors: Savocchia Sandra , Franks Tricia , Van Heeswijck Robyn 
Published: July 2003

AbstractA simple system for in vitro dual culture of grapevine (Vitis spp.) plantlets and root-knot nematode (Meloidogyne javanica (Treub) Chitwood) is described. Based on the presence or absence of mature females, or the total number of nematodes in the roots after 36-day co-culture, the system reliably discriminated resistant (cv. Ramsey) and susceptible (cv. Chardonnay) grapevines. The system was sensitive enough to differentiate between infestation levels of cvs Börner and Chardonnay, both susceptible in the in vitro conditions. A modification of the system to use plantlets from rooted petioles has reduced labour and space requirements and would suit mass screening of grapevine genotypes in traditional or genetic engineering-based breeding programmes. In both systems, nematodes in roots of cv. Ramsey tended to be associated with brown tissue and, compared with those in roots of cv. Chardonnay, were more likely to be confined to tips rather than be distributed along the root after co-culture for 11 or 36 days.
Nematodes of the order Rhabditida from Andalucía Oriental, Spain. The genus Chiloplacus Thorne, 1937, with description of C. maginensis sp. n. and a key to species
Authors: Peña-Santiago Reyes , Abolafia Joaquín 
Published: July 2003

AbstractFive known and one new species of the genus Chiloplacus Thorne, 1937 are studied from natural ecosystems in the SE Iberian Peninsula: C.demani (Thorne, 1925) Thorne, 1937, C. maginensis sp. n., C. minimus (Thorne, 1925) Andrássy, 1959, C. magnus Rashid & Heyns, 1990, C. tenuis Rashid & Heyns, 1990 and C. trilineatus Steiner, 1940. Chiloplacus maginensis sp. n. is characterised by a female body length of 272-345 μm, lateral field starting far anterior near the labial region and with five incisures, lip region with bifurcate labial probolae bearing short prongs, pharyngeal corpus 2.5-3.6 times isthmus length, ovary without flexures posterior to vulva, spermatheca 8-17 μm long, postuterine sac 0.2-0.5 of corresponding body diam. long, female tail conical with rounded terminus (12-20 μm; c´ = 15.0-26.6; c′ = 1.1-1.5), phasmid at 39-48% of tail length. Descriptions, measurements and illustrations, including SEM photographs, are provided for the six species recorded. The diagnosis of Chiloplacus is emended, the nominal species listed and a key provided to those nominal species currently regarded as valid.
Histological studies on the anatomy of the parasitic stages of Australonema sp. (Nematoda: Marimermithida)
Authors: Miljutin Dmitry 
Published: July 2003

AbstractParasitic stages (7-122 mm long) of Australonema sp. (Marimermithida, Enoplia) found in deep-sea polychaetes and in an echiurid from the Southern and Northern Atlantic, were studied histologically. The cephalic sensilla of the anterior end comprise six labial papillae and ten short cephalic papillae. The amphidial apertures are pore-like. Numerous tiny sensilla are distributed throughout the lateral regions of the body and there are eight hypodermal chords. A mouth opening, rectum and anus are all present. The pharynx is long and muscular with a triradial internal lumen, the pharyngeal glands opening almost at the apical part of the labia. The cardia is small with a triradial lumen. The midgut has a spacious lumen. The cervical excretory gland is two-cellular. The female genital system is amphidelphic, the germinal zone extending the length of the ovary (i.e., hologonic).
Comparative morpho-anatomical studies of the female gonoduct within the Pratylenchidae (Nematoda: Tylenchina)
Authors: Borgonie Gaëtan , Bert Wim , Van Gansbeke Ruben , Geraert Etienne , Claeys Myriam 
Published: July 2003

AbstractThe cellular morphology of the gonoduct of six Pratylenchus species, three Pratylenchoides species, Radopholus similis, Zygotylenchus guevarai, Hirschmanniella loofi and Nacobbus aberrans was revealed by dissection and light microscopy. Except for Nacobbus aberrans, all studied species show an overall similarity in gonoduct construction, i.e., an ovary often ending with a ring of cells, an oviduct formed from two rows of four cells and a 12-celled spermatheca followed by a tricolumella containing 16-24 cells. Pratylenchoides magnicauda and Z. guevarai did not diverge from the other Pratylenchidae in this respect, although their gonoduct differs from that of Amplimerlinius and Meloidogyne, both formerly postulated as related genera. The spermatheca structure observed in N. aberrans has not been reported elsewhere in the Nematoda, although the uterus is similar to that reported within the Heteroderinae and Meloidogyninae and the uterus comprises more than 300 cells, enlarging from a tricolumella to a polycolumella. Transmission electron microscopy of Z. guevarai revealed details of the cytoplasmatic contact between epithelial cells and the germ cells; a finger-like ovarian wall cell extension was found penetrating the oocyte. The oviduct lacks a preformed lumen and comprises eight cells with highly plicated cell membranes. The spermatheca is constructed from flattened wall cells and is followed by columnar uterus cells where evidence of eggshell formation was demonstrated.
Ultrastructure of the attachment and feeding sites of Gracilacus latescens Raski, 1976 in timber bamboo roots and selected anatomical details of the female stylet
Authors: Achor Dianne , Duncan Larry , Inserra Renato , Troccoli Alberto 
Published: July 2003

AbstractMature female Gracilacus latescens are sedentary and remain attached by the stylet to the surface of timber bamboo roots (Phyllostachys bambusoides) for their entire life. Observations by transmission electron microscopy (TEM) of the anatomy of the anterior portion of the female body showed the stylet shaft surrounded by a thick stomatal wall sensu Endo (1983) and by large protractor muscles. Cross sections of the root at the site of nematode attachment showed accumulation of electron-opaque material between the nematode body and the epidermal wall penetrated by the stylet. Electron-dense material enwrapped the stylet from the point of its insertion in an epidermal cell wall until its end in the lumen of a sclerenchymal or cortical cell. Two to three cells are penetrated by the stylet. The electron-dense material appeared to originate from the walls of epidermal, cortical parenchymal and sclerenchymal cells perforated by the stylet. The thickness of this material increased with the number of sclerenchyma cell walls penetrated by the stylet. Cross sections of the enwrapped stylet showed it tightly encased in the electron-dense material, which appeared to anchor the stylet and consequently the nematode body to the root surface. A syncytium originates from the innermost cell reached by the enwrapped stylet and expands into the inner cortex and stele. Cell wall dissolution and pit fields are characteristics of the syncytium.
The double contact phase in walking children
Authors: Bastien G. J. , Heglund N. C. , Schepens B. 
Published: July 2003

SUMMARYDuring walking, when both feet are on the ground (the double contact phase), the legs push against each other, and both positive and negative work are done simultaneously. The work done by one leg on the other(Wint,dc) is not counted in the classic measurements of the positive muscular work done during walking. Using force platforms, we studied the effect of speed and age (size) on Wint,dc. In adults and in 3-12-year-old children, Wint,dc (J kg-1 m-1) as a function of speed shows an inverted U-shaped curve, attaining a maximum value that is independent of size but that occurs at higher speeds in larger subjects. Normalising the speed with the Froude number shows that Wint,dc is maximal at about 0.3 in both children and adults. Differences due to size disappear for the most part when normalised with the Froude number, indicating that these speed-dependent changes are primarily a result of body size changes. At its maximum, Wint,dc represents more than 40% of Wext (the positive work done to move the centre of mass of the body relative to the surroundings) in both children and adults.
Into thin air: contributions of aerodynamic and inertial-elastic forces to wing bending in the hawkmothManduca sexta
Authors: Combes S. A. , Daniel T. L. 
Published: July 2003

SUMMARYDuring flapping flight, insect wings must withstand not only fluid-dynamic forces, but also inertial-elastic forces generated by the rapid acceleration and deceleration of their own mass. Estimates of overall aerodynamic and inertial forces vary widely, and the relative importance of these forces in determining passive wing deformations remains unknown. If aeroelastic interactions between a wing and the fluid-dynamic forces it generates are minor compared to the effects of wing inertia, models of insect flight that account for passive wing flexibility would be far simpler to develop. We used an experimental approach to examine the contributions of aerodynamic and inertial-elastic forces to wing bending in the hawkmoth Manduca sexta. We attached fresh Manduca wings to a motor and flapped them at a realistic wing-beat frequency and stroke amplitude. We compared wing bending in normal air versus helium (approx. 15% air density), in which the contribution of fluid-dynamic forces to wing deformations is significantly reduced. This 85% reduction in air density produced only slight changes in the pattern of Manduca wing deformations, suggesting that fluid-dynamic forces have a minimal effect on wing bending. We used a simplified finite element model of a wing to show that the differences observed between wings flapped in air versus helium are most likely due to fluid damping, rather than to aerodynamic forces. This suggests that damped finite element models of insect wings (with no fluid-dynamic forces included) may be able to predict overall patterns of wing deformation prior to calculations of aerodynamic force production, facilitating integrative models of insect flight.
Muscle force-length dynamics during levelversusincline locomotion: a comparison ofin vivoperformance of two guinea fowl ankle extensors
Authors: Daley Monica A. , Biewener Andrew A. 
Published: July 2003

SUMMARYFor a terrestrial animal to move in the complex natural environment, the limb muscles must modulate force and work performance to meet changing mechanical requirements; however, it is not clear whether this is accomplished via a collective shift in function by all limb muscles, or a division of labor among limb muscles. Do muscles differ in their ability to modulate force-length contractile function to meet the mechanical demands of different locomotor tasks? We explore this question by examining the in vivoforce-length performance of the guinea fowl Numida meleagris lateral gastrocnemius (LG) and digital flexor-IV (DF-IV), during level and incline locomotion. During level locomotion, the LG and DF-IV exhibit differing muscle fascicle strain patterns: the LG shortens by 10-15% while developing force,whereas the DF-IV undergoes a stretch-shorten cycle with large strain amplitudes and small net strains of 1-8%. Furthermore, the DF-IV operates at higher muscle stresses (92-130 kPa, compared to 23-39 kPa for LG) and possesses a longer tendon, which allows the DF-IV tendon to recover greater elastic energy than the LG tendon. During incline locomotion, these muscles contribute only one-third of the energy expected for their mass, with the DF-IV exhibiting high stride-to-stride variability in work output. While the stretch-shorten cycle of the DF-IV muscle may allow more economic force production, it also leads to large changes in work output with small changes in the relative timing of force and strain. Thus, while the primary determinants of LG work are net strain and mean force, the primary determinant of DF-IV work is the phase relationship between force and strain. Our results suggest that, in addition to influencing a muscle's mechanical performance during steady level locomotion, morphology also affects its capacity and mechanism for altering work output for different locomotor tasks.
Seasonal acclimatization in water flux rate, urine osmolality and kidney water channels in free-living degus: molecular mechanisms, physiological processes and ecological implications
Authors: Bozinovic Francisco , Gallardo Pedro A. , Visser G. Henk , Cortés Arturo 
Published: July 2003

SUMMARY
The environmental modification of an organism's physiology in the field is often hypothesized to be responsible for allowing an organism to adjust to changing biotic and abiotic environmental conditions through increases in biological performance. Here, we examine the phenotypic flexibility of water flux rate, urine osmolality and the expression of kidney aquaporins (AQP; or water channels) in free-ranging Octodon degus, a South American desert-dwelling rodent, through an integrative study at cellular, systemic and organismal levels. Water flux rates varied seasonally and were significantly lower in austral summer than in winter, while urine osmolality was higher in summer than during winter. The observed water influx rate during summer was 10.3±2.3 ml day-1 and during winter was 40.4±9.1 ml day-1. Mean urine osmolality was 3137±472 mosmol kg-1 during summer and 1123±472 mosmol kg-1during winter. AQP-2 medullary immunolabeling was more abundant in the kidneys of degus captured during summer than those captured during winter. This immunoreactivity was higher in apical cell membranes of medullary collecting ducts of degus in summer. AQP-1 immunostaining did not differ between seasons. Consistently, AQP-2 protein levels were increased in medulla from the summer individuals, as judged by the size of the 29 kDa band in the immunoblot. Here,we reveal how the integration of flexible mechanisms acting at cellular,systemic and organismal levels allows a small desert-dwelling mammal to cope with seasonal water scarcity in its semi-arid habitat.
The osmotic response of the Asian freshwater stingray (Himantura signifer) to increased salinity: a comparison with marine (Taeniura lymma) and Amazonian freshwater (Potamotrygon motoro)stingrays
Authors: Tam Wai L. , Wong Wai P. , Loong Ai M. , Hiong Kum C. , Chew Shit F. , Ballantyne James S. , Ip Yuen K. 
Published: July 2003

SUMMARYThe white-edge freshwater whip ray Himantura signifer can survive in freshwater (0.7‰) indefinitely or in brackish water (20‰) for at least two weeks in the laboratory. In freshwater, the blood plasma was maintained hyperosmotic to that of the external medium. There was approximately 44 mmol l-1 of urea in the plasma, with the rest of the osmolality made up mainly by Na+ and Cl-. In freshwater, it was not completely ureotelic, excreting up to 45% of its nitrogenous waste as urea. Unlike the South American freshwater stingray Potamotrygon motoro, H. signifer has a functional ornithine-urea cycle (OUC) in the liver, with hepatic carbamoylphosphate synthetase III (CPS III) and glutamine synthetase (GS) activities lower than those of the marine blue-spotted fan tail ray Taeniura lymma. More importantly, the stomach of H. signifer also possesses a functional OUC, the capacity(based on CPS III activity) of which was approximately 70% that in the liver. When H. signifer was exposed to a progressive increase in salinity through an 8-day period, there was a continuous decrease in the rate of ammonia excretion. In 20‰ water, urea levels in the muscle, brain and plasma increased significantly. In the plasma, osmolality increased to 571 mosmol kg-1, in which urea contributed 83 mmol l-1. Approximately 59% of the excess urea accumulated in the tissues of the specimens exposed to 20‰ water was equivalent to the deficit in ammonia excretion through the 8-day period, indicating that an increase in the rate of urea synthesis de novo at higher salinities would have occurred. Indeed, there was an induction in the activity of CPS III in both the liver and stomach, and activities of GS, ornithine transcarbamoylase and arginase in the liver. Furthermore, there was a significant decrease in the rate of urea excretion during passage through 5‰, 10‰ and 15‰ water. Although the local T. lymma in full-strength sea water (30‰)had a much greater plasma urea concentration (380 mmol l-1), its urea excretion rate (4.7 μmol day-1 g-1) was comparable with that of H. signifier in 20‰ water. Therefore, H. signifer appears to have reduced its capacity to retain urea in order to survive in the freshwater environment and, consequently, it could not survive well in full-strength seawater.
Postnatal suppression of myomesin, muscle creatine kinase and the M-line in rat extraocular muscle
Authors: Porter John D. , Merriam Anita P. , Gong Bendi , Kasturi Sriram , Zhou Xiaohua , Hauser Kurt F. , Andrade Francisco H. , Cheng Georgiana 
Published: July 2003

SUMMARYThe M-line and its associated creatine kinase (CK) M-isoform (CK-M) are ubiquitous features of skeletal and cardiac muscle. The M-line maintains myosin myofilaments in register, links the contractile apparatus to the cytoskeleton for external force transfer and localizes CK-based energy storage and transfer to the site of highest ATP demand. We establish here that the muscle group responsible for movements of the eye, extraocular muscle (EOM),is divergent from other striated muscles in lacking both an M-line and its associated CK-M. Although an M-line forms during myogenesis, both in vivo and in vitro, it is actively repressed after birth. Transcripts of the major M-line structural proteins, myomesin 1 and myomesin 2, follow the same pattern of postnatal downregulation, while the embryonic heart-specific EH-myomesin 1 transcript is expressed early and retained in adult eye muscle. By immunocytochemistry, myomesin protein is absent from adult EOM sarcomeres. M-line suppression does not occur in organotypic co-culture with oculomotor motoneurons, suggesting that the mechanism for suppression may lie in muscle group-specific activation or workload patterns experienced only in vivo. The M-line is, however, still lost in dark-reared rats, despite the developmental delay this paradigm produces in the visuomotor system and EOMs. EOM was low in all CK isoform transcripts except for the sarcomeric mitochondrial (Ckmt2) isoform. Total CK enzyme activity of EOM was one-third that of hindlimb muscle. These findings are singularly unique among fast-twitch skeletal muscles. Since EOM exhibits isoform diversity for other sarcomeric proteins, the M-line/CK-M divergence probably represents a key physiological adaptation for the unique energetics and functional demands placed on this muscle group in voluntary and reflexive eye movements.
Recovery of C-starts, equilibrium and targeted feeding after whole spinal cord crush in the adult goldfishCarassius auratus
Authors: Zottoli S. J. , Freemer M. M. 
Published: July 2003

SUMMARYCentral nervous system neurons of many adult teleost fish are capable of regrowth across spinal cord lesions, which may result in behavioral recovery of swimming. Since there have been few, if any, studies that examine the return of behaviors other than swimming, we provide a quantitative analysis of the recovery of C-starts that occur in adult goldfish after spinal cord injury. In addition, we include a qualitative analysis of the return of targeted feeding and equilibrium. Whole spinal cord crushes near the junction of the brain and spinal cord [spinomedullary level (SML)] were made in 45 experimental fish. Eight sham-operated goldfish served as controls for the effects of the surgery procedures alone. After spinal cord crush and recovery from the anesthetic, experimental fish lay on their sides with no movement caudal to the wound. The fish were monitored for the return of behaviors for up to 190 days postoperatively. Twenty-five fish survived the course of this study. Of these fish, 12 regained equilibrium and C-starts, two regained equilibrium but not C-starts, and 11 did not regain equilibrium (one of these did display a C-start). Twenty-two of the 25 experimental fish that survived the 190 days were able to target food from the water surface. Quantitative analysis of recovered C-starts in this study revealed that the probability of eliciting the response is reduced, that latencies from stimulus to response are longer and that movement parameters (i.e. angles, distance and velocity)are reduced compared with those of sham-operated control animals for up to 190 days postoperatively. The recovery of C-starts, equilibrium and targeted feeding was due to re-growth across the wound site, since re-crushing the spinal cord at the SML resulted in the loss of these behaviors. Mauthner cells are known to initiate C-starts in goldfish. Since the majority of M-axons that regrow across a crush wound associate with an inappropriate pathway (i.e. the first ventral root), it is unlikely that these cells play a major role in the return of C-starts. We propose that regeneration of Mauthner cell homologues across the wound site is responsible for the recovery of most C-starts. The identifiability of the M-cell and its homologues provides a unique opportunity to analyze the mechanisms underlying behavioral recovery at the cellular level.
Stimulatory effect of sulphide on thiotaurine synthesis in three hydrothermal-vent species from the East Pacific Rise
Authors: Pruski Audrey M. , Fiala-Médioni Aline 
Published: July 2003

SUMMARYSymbiotic associations between marine invertebrates and sulphur-oxidising bacteria are a common feature in communities from sulphide-rich environments,such as those flourishing in the vicinity of hydrothermal vents. While the bacterial endosymbionts provide the host with an undoubted nutritional advantage, their presence also requires specific adaptations for the transport and storage of sulphide, which is a potent toxin of aerobic respiration. Although different mechanisms such as the reversible binding of sulphide to serum binding proteins or its oxidation to less toxic forms have been described, many questions still remained unanswered. In the last decade, large amounts of thiotaurine, an unusual sulphur-amino acid, have been reported in sulphur-based symbioses from hydrothermal vents and cold seeps. Compounds such as thiotaurine are known to take part in trans-sulphuration reactions, so the involvement of thiotaurine in sulphide metabolism has been suggested. We present here an experimental study on thiotaurine biosynthesis in three sulphur-oxidising symbiont-bearing species from the East Pacific Rise: the vesicomyid Calyptogena magnifica, the mytilid Bathymodiolus thermophilus and the vestimentiferan Riftia pachyptila. In all three species, thiotaurine synthesis is stimulated in vitro by an input of sulphide, as well as by thiosulphate in B. thermophilus. Several distinct metabolic pathways seem to occur, however, since hypotaurine is the only precursor in the bivalves C. magnifica and B. thermophilus, whereas thiotaurine is also produced from taurine in R. pachyptila. Hypotaurine(NH2-CH2-CH2-SO2H) and thiotaurine(NH2-CH2-CH2-SO2SH) are two free sulphur amino acids whose chemical formulae differ by only one atom of sulphur. It appears that the extent of thiotaurine synthesis is strongly dependent on the initial equilibrium between these two amino acids, since the strongest thiotaurine synthesis rates are found in tissues with the lowest initial thiotaurine concentration. Moreover, the lack of any effect of sulphide in symbiont-free tissues and in gills of the methanotrophic mussel Bathymodiolus childressi reinforces the assumption that thiotaurine synthesis is a specific adaptation to the thiotrophic mode of life. While the precise function (i.e. transport and/or storage of sulphide) of hypotaurine and thiotaurine has yet to be established, our results strongly support a general role for these free amino acids in the metabolism of sulphide in hydrothermal-vent thiotrophic symbioses.