Second Peak Of Activity Research Articles

Multiple physiological cohorts comprise seasonal activity of wild Amblyomma americanum (Acari: Ixodidae) nymphs

Nymphs of the hard tick Amblyomma americanum (L.) are an important life stage in the maintenance and transmission of tick-borne pathogens. As pathogen composition can vary across developmental cohorts, it is essential to understand the demographic structure of the questing population. Amblyomma americanum nymphs often display a second peak in activity during late summer, but it is unknown whether this peak represents older overwintered ticks or younger newly molted ticks. The objective of this study was to examine the heme concentration in field-captured A. americanum nymphs to determine if the questing population consists of one physiological cohort or multiple cohorts in a season. Ticks were collected from March to August in an old field of primarily non-native grasses, and heme concentration was used to assess physiological age. LOESS modeling depicted that heme concentration in the population declined from March to early July but increased in later sampling sessions. As ticks cannot replenish declining heme stores without a blood meal, a late-summer spike in heme concentration demonstrates that newly molted nymphs are entering the active population. The vector potential of these newly emerging nymphs may differ from those collected earlier in the year as pathogen diversity depends on reservoir host dynamics and timing of larval feeding.

Seasonal activity of ixodid ticks in Podilskyi region

Ixodid ticks are the most important arthropod hematophagies in veterinary medicine. The spread of ticks and tick borne diseases is linked to human activities, including habitat change, deforestation, economic globalization, international animal movements, urbanization and climate change. The research was conducted from March 2018 to March 2019 in Khmelnytsky region. In total were collected 2086 D. reticulatus ticks and 658 I. ricinus ticks. During the studies, two peaks of seasonal activity of both species of ticks were observed according to the average number of specimens in the three study areas. Spring activity began in March, and the peak was observed in April. Males were found to be more active in March and the first half of April, while females dominated males from late May to late June. The second peak of activity in the study area began in mid-September. Since the beginning of September, the activity of ticks has increased almost eight times compared to August. The peak of autumn activity was observed in late October and early November. Active females dominated males from early October to late autumn. From mid-June to mid-September, single specimens of ticks were detected. During the winter, no ticks were found in the experimental plots. On average, in all experimental areas of Khmelnytsky region, ticks were active at a temperature of 10.8 to 27.8 °C (average temperature – 21.6 ± 6.57 °C) and humidity – 39.90–78.20 % (average humidity – 61.79 %). Statistical analysis performed for all study areas showed that air temperature significantly affected the activity of both species of ticks. However, correlations between the number of ticks collected and humidity throughout the study area and in different areas were not observed separately. The largest number of ticks was collected during the period when daylight lasted approximately 12–14 hours; in turn, the lowest number of ticks was detected on days with more than 15 hours of daylight. Statistical analysis confirmed the correlation between the length of daylight and the activity of ticks of both species.

Functional organisation of the endomembrane network in the digestive gland of the Venus flytrap: revisiting an old story with a new microscopy toolbox.

Up-to-date imaging approaches were used to address the spatiotemporal organisation of the endomembrane system in secretory cells of Dionaea muscipula. Different 'slice and view' methodologies were performed on resin-embedded samples to finally achieve a 3D reconstruction of the cell architecture, using ultrastructural tomography, array tomography, serial block face-scanning electron microscopy (SBF-SEM), correlation, and volume rendering at the light microscopy level. Observations of cryo-fixed samples by high-pressure freezing revealed changes of the endomembrane system that occur after trap activation and prey digestion. They provide evidence for an original strategy that adapts the secretory machinery to a specific and unique case of stimulated exocytosis in plant cells. A first secretion peak is part of a rapid response to deliver digestive fluids to the cell surface, which delivers the needed stock of digestive materials 'on site'. The second peak of activity could then be associated with the reconstruction of the Golgi apparatus (GA), endoplasmic reticulum (ER) and vacuolar machinery, in order to prepare for a subsequent round of prey capture. Tubular continuum between ER and Golgi stacks observed on ZIO-impregnated tissues may correspond to an efficient transfer mechanism for lipids and/or proteins, especially for use in rapidly resetting the molecular GA machinery. The occurrence of one vacuolar continuum may permit continuous adjustment of cell homeostasy. The subcellular features of the secretory cells of Dionaea muscipula outline key innovations in the organisation of plant cell compartmentalisation that are used to cope with specific cell needs such as the full use of the GA as a protein factory, and the ability to create protein reservoirs in the periplasmic space. Shape-derived forces of the pleiomorphic vacuole may act as signals to accompany the sorting and entering flows of the cell.

Properties and temporal dynamics of choice- and action-predictive signals during item recognition decisions

Decision-making is in the service of action regardless of whether the decision concerns perceptual information, goods or memories. Compared to recent advances in the neurobiology of perceptual or value-based decisions, however, the neural bases supporting the sampling of evidence in long-term memory, and the transformation of memory-based decisions into appropriate actions, are still poorly understood. In the present fMRI study, we used multivariate pattern analysis to investigate the temporal dynamics of choice- and action-predictive signals during an item recognition task that manipulated the association between memory choices (old/new) and motor responses (eye/hand) across subjects. Choice-predictive activity was mainly observed in striatal, lateral prefrontal and lateral parietal regions, was sensitive to the amount of decision evidence and showed a rapid increase after stimulus onset, followed by a fast decay. Action-predictive signals were found in primary sensory motor, premotor and occipito–parietal regions, were generally observed at the end of the decision phase and were not modulated by decision evidence. These findings suggest that a memory decision variable, potentially represented in a fronto–striato–parietal network, is not directly transformed into an action plan as often observed in perceptual decisions. Regions exhibiting choice predictive activity, and especially the striatum, however, also showed a second peak of decision-related activity that, unlike pure choice- or action-predictive signals, depended on the particular choice–response association. This second peak of activity in the striatum might represent the neural signature of the transformation of a memory decision into an appropriate motor response based on the specific choice–response association.

Factors Affecting Population Dynamics of Thrips Vectors of Soybean vein necrosis virus.

Thrips-infesting soybeans were considered of minor economic importance, but recent evidence of their ability to transmit a newly identified soybean virus, Soybean vein necrosis virus (SVNV), has raised their profile as pests. Season-long surveys were conducted using suction traps to determine the effects of temperature and precipitation on the spatiotemporal patterns of three vector species of SVNV, Neohydatothrips variabilis (Beach) (Thysanoptera: Thripidae) (soybean thrips), Frankliniella tritici (Fitch) (Thysanoptera: Thripidae) (eastern flower thrips), and Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) (tobacco thrips) in soybean fields in Indiana in 2013 and 2014. In addition, soybean fields were surveyed for presence of SVNV in both years. We found that the magnitude and timing of thrips activity varied greatly for the three species. N. variabilis activity peaked in mid-August each year. The peak activity for F. tritici occurred between late-June, and a second peak in activity was observed in early-August, while F. fusca activity remained more or less the same with no peak. There was no gradient in thrips populations from southern to northern locations. This suggests that these insects are not migratory and may overwinter in soil or perennial noncrop host plants and other weed hosts in Indiana. The capture rates of N. variabilis and F. tritici were only related to temperature, and capture rates of F. fusca were not related to either variable. SVNV was first detected in mid-late August, which coincided with the peak of the primary vector, N. variabilis. The virus was not detected earlier in the season despite peaks in F. tritici activity. Our results may be used in weather-based models to predict both thrips dynamics as well as SVNV outbreaks.

Spatial Ecology of Sonoran Desert Tortoises (Gopherus morafkai): I. Fidelity in Home Range, Refuge Use and Foraging Behavior

Abstract The behavioral ecology of Sonoran Desert Tortoises (Gopherus morafkai) remains relatively unstudied. In general, Sonoran Desert Tortoises (SDTs) differentially use incised washes and rocky slopes and avoid open flats and intermountain valleys, except during apparent emigration events. We know relatively little about the temporal pattern of space use in SDTs and even less about such use in relation to sex. We observed activity of adult and juvenile SDTs via radiotelemetry, and hatchling activity incidentally, over a 3-yr period in central Arizona. The SDTs were most active in the fall (August–October) but exhibited a second peak of activity in the spring (April). On average, males moved longer distances than did females in every month of the year when SDTs were active. Distance moved by females in the fall was significantly greater than all other months except April; a similar pattern of greater male movement in the fall was apparent but not statistically significant. Activity of adults was detect...

Modeling of respiratory network: to sigh or not to sigh

The Pre-Botzinger Complex (PreBotC), a medullary brainstem region, is essential for generating breathing. Isolated in a transverse slice preparation, the preBotC continues to generate under normal conditions eupneic and at a lower frequency also sighs. The mechanisms generating the periodicity of fictive sighs as well as its intrinsic nature are largely unknown. Based the experimental observations such as 1) has the biphasic shape characterized as eupneic breath interrupted by augmentation with a second peak of activity, 2) the biphasic shape persists after blockage of inhibitory synapses, 3) the network is heterogeneous, we model PreBotC network that reproduces both types of activities. The model contains three types of neurons: intrinsically tonic spiking, intrinsic bursting neurons and intrinsic quiescent. Neurons within the network are sparsely connected through randomly distributed excitatory synapses. In this model we propose that the mechanism of generation is based slow oscillations generated by glia. Moreover, the model predicts that depending the modularity state of the system, the network exhibits sighs, does not exhibit sighs and shows only eupneic activity, or shows bi-stable activity meaning that sighs can be triggered between on and off states by short perturbation. The bistability depends slow calcium oscillations. The network model predicts that the presence of IP3-like channels is necessary to produce sigh behavior and to mimic transitions between activity states caused by neuromodulators. We analyze the model dynamics and describe dose-response curve to neuromodulator such as norepinephrine. Theoretical data are similar to experimental data from in vitro brain slice preparations and in vivo anesthetized mice.

Why on the snow? Winter emergence strategies of snow-active Chironomidae (Diptera) in Poland.

A long-term study of adult non-biting midges (Chironomidae) active in winter on the snow in mountain areas and lowlands in Poland yielded 35 species. The lowland and mountain communities differed significantly in their specific composition. The mountain assemblage was found to be more diverse and abundant, with a substantial contribution from the subfamily Diamesinae, whereas Orthocladiinae predominated in the lowlands. Orthocladius wetterensis Brundin was the most characteristic and superdominant species in the winter-active chironomid communities in both areas. Only a few specimens and species of snow-active chironomids were recorded in late autumn and early winter. The abundance of chironomids peaked in late February in the mountain and lowland areas with an additional peak in the mountain areas in early April. However, this second peak of activity consisted mainly of Orthocladiinae, as Diamesinae emerged earliest in the season. Most snow-active species emerged in mid- and late winter, but their seasonal patterns differed between the 2 regions as a result of the different species composition and the duration of snow cover in these regions. Spearman's rank correlation coefficient tests yielded positive results between each season and the number of chironomid individuals recorded in the mountain area. A positive correlation between air temperature, rising to +3.5 °C, and the number of specimens recorded on the snow in the mountain community was statistically significant. The winter emergence and mate-searching strategies of chironomids are discussed in the light of global warming, and a brief compilation of most important published data on the phenomena studied is provided.

In an in vitro model of human tuberculosis, monocyte-microglial networks regulate matrix metalloproteinase-1 and -3 gene expression and secretion via a p38 mitogen activated protein kinase-dependent pathway

BackgroundTuberculosis (TB) of the central nervous system (CNS) is characterized by extensive tissue inflammation, driven by molecules that cleave extracellular matrix such as matrix metalloproteinase (MMP)-1 and MMP-3. However, relatively little is known about the regulation of these MMPs in the CNS.MethodsUsing a cellular model of CNS TB, we stimulated a human microglial cell line (CHME3) with conditioned medium from Mycobacterium tuberculosis-infected primary human monocytes (CoMTb). MMP-1 and MMP-3 secretion was detected using ELISAs confirmed with casein zymography or western blotting. Key results of a phospho-array profile that detects a wide range of kinase activity were confirmed with phospho-Western blotting. Chemical inhibition (SB203580) of microglial cells allowed investigation of expression and secretion of MMP-1 and MMP-3. Finally we used promoter reporter assays employing full length and MMP-3 promoter deletion constructs. Student’s t-test was used for comparison of continuous variables and multiple intervention experiments were compared by one-way ANOVA with Tukey’s correction for multiple pairwise comparisons.ResultsCoMTb up-regulated microglial MMP-1 and MMP-3 secretion in a dose- and time-dependent manner. The phospho-array profiling showed that the major increase in kinase activity due to CoMTb stimulation was in p38 mitogen activated protein kinase (MAPK), principally the α and γ subunits. p38 phosphorylation was detected at 15 minutes, with a second peak of activity at 120 minutes. High basal extracellular signal-regulated kinase activity was further increased by CoMTb. Secretion and expression of MMP-1 and MMP-3 were both p38 dependent. CoMTb stimulation of full length and MMP-3 promoter deletion constructs demonstrated up-regulation of activity in the wild type but a suppression site between -2183 and -1612 bp.ConclusionsMonocyte-microglial network-dependent MMP-1 and MMP-3 gene expression and secretion are dependent upon p38 MAPK in tuberculosis. p38 is therefore a potential target for adjuvant therapy in CNS TB.

Production optimization and properties of beta glucosidases from a marine fungus Aspergillus-SA 58

Aspergillus strain SA 58, showing considerable beta glucosidase production was selected as the potential strain. The fungus showed enzyme production in both acidic and alkaline pH. A temperature of 35 degrees C was found to be optimum for enzyme production. Maximum enzyme production was seen when pectin was used as the carbon source (80 U/ml). In solid-state fermentation, an enzyme production of 6200 U/g Initial Dry Substrate was noted. The strain produced two extra cellular enzymes and two intra cellular enzymes. For both the extra cellular enzymes (BGL A and BGL B), 60 degrees C was found to be optimum temperature for activity. BGL A showed an optimum pH of 4.0 while BGL B showed an optimum pH of 3.0 for activity. Both the enzymes showed a second peak of activity at pH 9.0. Both BGL A and BGL B showed high thermal stabilities with residual activities of 86% and 85% even after 6h of incubation at 50 degrees C.

Specific features of nitrogen transformation in the gut and coprolites of earthworms

It has been found that nitrogenase activity in the guts and coprolites of three earthworm species (Lumbricus terrestris, Aporrectodea rosea, and Aporrectodea caliginosa) is one to three orders of magnitude higher than that in the control soil. In A. caliginosa earthworms, the actual nitrogenase activity remains high upon keeping them in soils of different types. However, it reaches a peak in the gut lumen and decreases to a minimum on its wall, which is evidence for a major role of transitional microflora in intestinal nitrogen fixation. Nitrogen fixation activity in freshly excreted coprolites decreases to one-half or one-third of that in the gut and then increases again, reaching a peak on days 3-5 of exposure in the soil. According to the results of multisubstrate testing, the functional diversity of nitrogen-fixing soil microorganisms increases in the course of passage through the earthworm gut. Thus, the microbial community in coprolites retains its functional potential and, within a few days, shows the second peak of activity in the soil. Due to a short-term increase in the rate of nitrogen fixation, coprolites contain a pool of bound amino acids, which become involved in the formation of new humus substances.

Stachybotrys atra BP-A produces alkali-resistant and thermostable cellulases

A cellulose-degrading fungal strain has been isolated from a rotten rag. Morphological characterization and ITS1, 5.8S and ITS2 rDNA sequencing showed that the strain is a new isolate of Stachybotrys atra. The strain secreted high cellulase activity in media supplemented with rice straw. However, cellulases were not produced in glucose-supplemented media. The crude cellulase showed the highest activity on amorphous celluloses such as carboxymethyl cellulose, while activity on crystalline celluloses such as Avicel was lower. The optimal temperature and pH for CMCase activity were 70 degrees C and pH 5 respectively, although a second peak of activity was found at pH 8. Activity was strongly inhibited by Cu(2+), Mn(2+) and Hg(2+). Analysis by SDS-PAGE, isoelectric focusing and zymography showed that the strain secretes a complex cellulase system comprising several enzymes. Most of these enzymes are alkali-resistant CMCases that remained stable at pH 9 and 65 degrees C for at least 1 h. Cellulose binding assays showed notable differences among the CMCases. While some CMCase bands did not bind Avicel, other bands bound to this polymer and were eluted either with NaCl or by boiling with SDS. Analysis by two-dimensional electrophoresis showed that the band eluted by SDS boiling contained at least 4 different polypeptides. The complex set of cellulases produced by the strain, and their activity and stability at alkaline pH and a high temperature indicate that both the isolated strain and the cellulases identified are good candidates for biotechnological applications involving cellulose modification.

Separate Modulations of Human V1 Associated with Spatial Attention and Task Structure

Functional magnetic resonance imaging (fMRI) was used while normal human volunteers engaged in simple detection and discrimination tasks, revealing separable modulations of early visual cortex associated with spatial attention and task structure. Both modulations occur even when there is no change in sensory stimulation. The modulation due to spatial attention is present throughout the early visual areas V1, V2, V3, and VP, and varies with the attended location. The task structure activations are strongest in V1 and are greater in regions that represent more peripheral parts of the visual field. Control experiments demonstrate that the task structure activations cannot be attributed to visual, auditory, or somatosensory processing, the motor response for the detection/discrimination judgment, or oculomotor responses such as blinks or saccades. These findings demonstrate that early visual areas are modulated by at least two types of endogenous signals, each with distinct cortical distributions.

Xylanases of marine fungi of potential use for biobleaching of paper pulp.

Microbial xylanases that are thermostable, active at alkaline pH and cellulase-free are generally preferred for biobleaching of paper pulp. We screened obligate and facultative marine fungi for xylanase activity with these desirable traits. Several fungal isolates obtained from marine habitats showed alkaline xylanase activity. The crude enzyme from NIOCC isolate 3 (Aspergillus niger), with high xylanase activity, cellulase-free and unique properties containing 580 U l(-1) xylanase, could bring about bleaching of sugarcane bagasse pulp by a 60 min treatment at 55 degrees C, resulting in a decrease of ten kappa numbers and a 30% reduction in consumption of chlorine during bleaching. The culture filtrate showed peaks of xylanase activity at pH 3.5 and pH 8.5. When assayed at pH 3.5, optimum activity was detected at 50 degrees C, with a second peak of activity at 90 degrees C. When assayed at pH 8.5, optimum activity was seen at 80 degrees C. The crude enzyme was thermostable at 55 degrees C for at least 4 h and retained about 60% activity. Gel filtration of the 50-80% ammonium sulphate-precipitated fraction of the crude culture filtrate separated into two peaks of xylanase with specific activities of 393 and 2,457 U (mg protein)(-1). The two peaks showing xylanase activity had molecular masses of 13 and 18 kDa. Zymogram analysis of xylanase of crude culture filtrate as well as the 50-80% ammonium sulphate-precipitated fraction showed two distinct xylanase activity bands on native PAGE. The crude culture filtrate also showed moderate activities of beta-xylosidase and alpha- l-arabinofuranosidase, which could act synergistically with xylanase in attacking xylan. This is the first report showing the potential application of crude culture filtrate of a marine fungal isolate possessing thermostable, cellulase-free alkaline xylanase activity in biobleaching of paper pulp.

Gene expression changes accompanying p53 activity during estrogen treatment of osteoblasts

Estrogen is known to be anabolic for bone and we have used estrogen treatment as a paradigm to understand how p53 may affect osteoblast differentiation. In previous studies we have shown estrogen treatment to increase p53 functional activity in osteoblasts. Estrogen has been suggested to inhibit apoptosis in osteoblasts. Since the significance of a p53 increase during estrogen treatment is not apparent, we investigated the environment within osteoblasts after treatment with estrogen. We observed two peaks of p53 activity during continuous treatment of 17-[beta]-estradiol (E 2) for 72h. The gene expression profile of different cell cycle regulators and apoptosis related genes at different times during treatment with 17-[beta]-estradiol were tested using gene arrays. There was an early increase in expression of several genes involved in apoptosis. This was followed by changes in expression of several genes involved in cell survival and stress response. The second peak of activity was associated with increase in expression of cell cycle regulators. Our results suggest that p53 activity may be a result of activation of several signaling pathways involving apoptosis, cell survival and cell cycle arrest. P53 may have a role in integrating these responses, which eventually results in cell cycle arrest and expression of differentiation markers.

Purification, Characterization, and Subunit Structure of Rat Core 1 β1,3-Galactosyltransferase

The O-linked oligosaccharides (O-glycans) in mammalian glycoproteins are classified according to their core structures. Among the most common is the core 1 disaccharide structure consisting of Galbeta1-->3GalNAcalpha1-->Ser/Thr, which is also the precursor for many extended O-glycan structures. The key enzyme for biosynthesis of core 1 O-glycan from the precursor GalNAc-alpha-Ser/Thr is UDP-Gal:GalNAc-alpha-Ser/Thr beta3-galactosyltransferase (core1 beta3-Gal-T). Core 1 beta3-Gal-T activity, which requires Mn2+, was solubilized from rat liver membranes and purified 71,034-fold to apparent homogeneity (>90% purity) in 5.7% yield by ion exchange chromatography on SP-Sepharose, affinity chromatography on immobilized asialo-bovine submaxillary mucin, and gel filtration chromatography on Superose 12. The purified enzyme is free of contaminating glycosyltransferases. Two peaks of core 1 beta3-Gal-T activity were identified in the final step on Superose 12. One peak of activity contained protein bands on non-reducing SDS-PAGE of approximately 84- and approximately 86-kDa disulfide-linked dimers, whereas the second peak of activity contained monomers of approximately 43 kDa. Reducing SDS-PAGE of these proteins gave approximately 42- and approximately 43-kDa monomers. Both the 84/86-kDa dimers and the 42/43-kDa monomers have the same novel N-terminal sequence. The purified enzyme, which is remarkably stable, has an apparent Km for UDP-Gal of 630 microm and an apparent Vmax of 206 micromol/mg/h protein using GalNAcalpha1-O-phenyl as the acceptor. The reaction product was generated using asialo-bovine submaxillary mucin as an acceptor; treatment with O-glycosidase generated the expected disaccharide Galbeta1-->3GalNAc. These studies demonstrate that activity of the core 1 beta1,3-Gal-T from rat liver is contained within a single, novel, disulfide-bonded, dimeric enzyme.

Indices to describe different muscle activation patterns, identified during treadmill walking, in people with spastic drop-foot

This study was concerned with individuals who were unable to effectively dorsiflex their ankle when walking, as a result of a lesion of the central nervous system (CNS). Indices that categorise and quantify different patterns of calf and anterior tibial muscle activation patterns during treadmill walking have been derived from a sample of fifteen individuals with established hemiplegia following stroke and twelve age-matched individuals without impairment. As subjects walked on a treadmill, force sensitive foot-switches under the heel and first metatarsal head allowed EMG signals from the calf and anterior tibial muscles to be related to phases of the gait cycle. Normal activation periods for each muscle group were identified as percentiles of the gait cycle and indices for muscle activation periods were derived using ratios of integrated EMG during selected periods. Indices were derived that identified statistically significant differences, between normal and hemiplegic subjects, in calf activation during both push-off phase ( P<0.001) and early stance phase ( P<001), but not activation of tibialis anterior during swing ( P=0.325) Observation suggested that integrated tibialis anterior activity during swing phase in hemiplegic subjects was not dissimilar to normal subjects, but the profile in hemiplegic subjects tended to lack the normal second peak of activity at initial foot contact. The reasons for drop-foot were shown to be varied and complex. The indices defined may be useful for directing therapy and measuring outcome.

Histone deacetylases in replicative senescence: evidence for a senescence-specific form of HDAC-2

To analyze mechanisms of senescence-associated gene expression, we have investigated histone deacetylases (HDACs) in human fibroblasts undergoing replicative senescence. We found that the overall acetylation pattern of histones does not vary detectably with replicative senescence. By Northern blot and Western blot, we found a significant decrease in the abundance of HDAC-1 in senescent cells. Biochemical analysis of deacetylase activities in extracts from old and young cells revealed a striking difference. While by anion exchange chromatography we found a single peak of activity in extracts from young cells, which coincided with the elution of both HDAC-1 and HDAC-2, in senescent cells a second peak of activity was found. This second peak of activity is associated with HDAC-2 but does not contain HDAC-1. These results suggest that HDAC-2 is present in at least two distinct forms, one of which is specific for senescent cells. Further biochemical characterization of the enzyme activity revealed that addition of nicotinamide adenine dinucleotide (NAD) did not detectably influence the activity of any fraction, suggesting that NAD is not an essential co-factor for the analyzed HDACs from diploid human fibroblasts.

Positional specificity of a phospholipase A activity induced by wounding, systemin, and oligosaccharide elicitors in tomato leaves

Phospholipase A (PLA) activity, as measured by the accumulation of (14)C-lysophosphatidylcholine in leaves of tomato plants, increased rapidly and systemically in response to wounding. The increase in PLA activity in the systemic unwounded leaves was biphasic in wild-type tomato plants, peaking at 15 min and again at 60 min, but the second peak of activity was absent in transgenic prosystemin antisense plants. Supplying young excised tomato plants with the polypeptide hormone systemin also caused (14)C-lysophosphatidylcholine to increase to levels similar to those induced by wounding, but the increase in activity persisted for >2 hr. Antagonists of systemin blocked both the release of (14)C-lysophosphatidylcholine and the accumulation of defense proteins in response to systemin. (14)C-lysophosphatidylcholine levels did not increase in response to jasmonic acid. Chemical acylation of the lysophosphatidylcholine produced by wounding, systemin, and oligosaccharide elicitors followed by enzymatic hydrolysis with lipases of known specificities demostrated that the lysophosphatidylcholine is generated by a PLA with specificity for the sn-2 position.

Changes in the Creatine Kinase and Lactate Dehydrogenase Activities in Cerebrospinal Fluid of Dogs with Thoracolumbar Disc Disease

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