Presence Of Exudates Research Articles

Redescriptions of species of Ancyrocephaloides Yamaguti, 1938 (Monogenea: Ancyrocephalidae) from triacanthid fishes caught off Peninsular Malaysia and a report of their haptoral secretions

Numerous specimens of Ancyrocephaloides triacanthi Yamaguti, 1938 and A. chauhani Bychowsky & Nagibina, 1975 were collected from two triacanthid fishes, Triacanthus biaculeatus and Tripodichthys blochii, off Peninsular Malaysia. The two monogenean species are redescribed and considered to be the only valid species of Ancyrocephaloides Yamaguti, 1938. Examinations of these worms revealed new features, e.g. the presence of exudates (both net-like and bundle-like) and superficial grooves in the anchors in both species, which necessitated re-descriptions of the two species and amendments to the generic diagnosis. Both species have relatively small anchors with two lateral superficial grooves along the shaft and point, peduncular glands and four large, pyriform secretory reservoirs in the peduncular-haptoral region, each with a single tubular extension to an associated anchor, and net-like structures (exudate) attached to the anchors. The net-like structures are one of the external manifestations of the secretion produced in the peduncular glands and stored in the pyriform secretory reservoirs. When released within the gill-tissue of the host, the exudate is in the form of bundles which extend within the gill-filament. The small anchors convey secretions from the secretory reservoirs via lateral superficial grooves into the gills as the anchors pierce the host tissue for attachment. The secretion coagulates as left and right thread-like bundles of exudate within the gill tissues and is only apparent as nets when it is released into the surrounding water. The recurved point of the anchor and position of the point of exudation allow the nets to remain attached to the anchor point, even after the detachment of the anchors from the gill tissue. This exudate possibly acts somewhat like a 'belay device' or 'safety belt', preventing the parasite from being washed away by the respiratory current during the onset of its leech-like locomotion, as well as assist the relatively small anchors in attachment.

Changes in Azospirillum brasilense motility and the effect of wheat seedling exudates

The rhizobacterium Azospirillum brasilense Sp245 swims, swarms (Swa(+) phenotype) or, very rarely, migrates with the formation of granular macrocolonies (Gri(+) phenotype). Our aims were (i) to identify Sp245 mutants that swarm faster than the parent strain or differ from it in the mode of spreading and (ii) to compare the mutants' responses to wheat seedling exudates. In isotropic liquid media, the swimming speeds of all motile A. brasilense strains were not influenced by the exudates. However, the exudates significantly stimulated the swarming of Sp245. In several Sp245 mutants, the superswarming phenotype was insensitive to local colonial density and to the presence of wheat seedling exudates. An A. brasilense polar-flagellum-defective Gri(+) mutant BK759.G gave rise to stable Swa(++) derivatives with restored flagellum production. This transition was concurrent with plasmid rearrangements and was stimulated in the presence of wheat seedling exudates. The swarming rate of the Swa(++) derivatives of BK759.G was affected by the local density of their colonies but not by the presence of the exudates.

The influence of Myriophyllum verticillatum and artificial plants on some life history parameters of Daphnia magna

Submerged macrophytes are known to serve as refuge for zooplankton but also seem to suppress the zooplankton growth. Thus, there is a conflict between the positive and negative role of macrophytes for zooplankton. We tested the influence of physical structure using artificial macrophytes, chemicals released by a macrophyte (Myriophyllum verticillatum), as well as the combined effects of these two factors on the life history of Daphnia magna. Daphnids matured at a smaller size and produced fewer eggs but larger individual offspring in the presence of artificial and real plants. Thus, under conditions with plants, we observed a trade off between number of eggs produced and the individual size of the offspring. Daphnids grown in the presence of exudates without plants were larger at maturity and showed no reduction in clutch size as compared with the control. We suggest that the macrophytes (real and artificial) negatively affected the daphnids in two ways: (1) food particles were settling down faster on the plant structures and this reduced the available food for Daphnia, (2) the plant structures were obstacles for the daphnids causing them to spent more energy during swimming. Both effects resulted in a reduced somatic growth, whereas the increased individual offspring size was probably a response to the reduced food level. Daphnia was not negatively affected by Myriophyllum exudates.

Onicolisis con exudado del hiponiquio secundaria a quimioterapia con paclitaxel y capecitabina

A 39-year-old female patient who consulted due to onycholysis, subungual hyperkeratosis and presence of exudates in the big toe of the right foot. The lesions appeared during oncology treatment of bilateral breast cancer with lymphatic metastases with paclitaxel every three weeks and capecitabine daily. Clinical manifestations are due to the involvement of the nail bed caused by the chemotherapy. These should be known and taken into account due to the increased use of this type of cytotoxic agents.

Features associated with surgical outcome in patients with stages 4 and 5 retinopathy of prematurity.

To present ocular features associated with surgical outcomes in infants with stages 4 and 5 retinopathy of prematurity (ROP). Twenty-two infants (35 eyes) were referred for vitreoretinal surgery for stages 4 and 5 ROP. The following ocular features recorded before the development of retinal detachment requiring surgical intervention were analyzed: clock hour extent of ridge elevation, vitreous state, plus disease, prominent iris vessels, neovascularization, and the presence of exudates. Surgical procedures included scleral buckle, lensectomy-vitrectomy, and lens-sparing vitrectomy. Univariate and multivariate analyses were used to determine features associated with failure to achieve retinal reattachment as the main outcome variable. Of the 35 eyes that underwent at least one surgical procedure, nine had successful retinal reattachment after the first surgery, and 18 achieved it at the end of follow-up. After accounting for the correlation between the eyes, features significantly associated with surgical failure after the first surgery were vitreous haze, hemorrhage, or organization; plus disease; and neovascularization. The presence of exudates was significantly associated with a successful outcome. When eyes were analyzed by stage at the first procedure, vitreous organization and plus disease were associated with failed retinal reattachment in stage 4 eyes, whereas at least 6 clock hours of ridge elevation and plus disease were significant in stage 5 eyes. The need to perform a lensectomy-vitrectomy was associated with a poor surgical outcome. Neither stage nor number of procedures performed was associated with the development of phthisis. Vitreous haze, neovascularization, and plus disease are associated with a poor surgical outcome in eyes that progress after treatment for threshold ROP requiring surgical intervention for retinal detachment. When eyes were divided by stage of ROP at first surgery, plus disease remained a significant variable associated with failed retinal reattachment. Close observation of eyes after laser treatment for threshold ROP is necessary. If neovascularization and plus disease persist and progression of ROP is noted, additional laser should be considered before surgery for retinal detachment. Additional studies with a larger patient sample will be necessary to further define ocular features associated with surgical outcome for ROP.

Turnover and distribution of root exudates of Zea mays

Decomposition and distribution of root exudates of Zea mays L. were studied by means of 14CO2 pulse labeling of shoots on a loamy Haplic Luvisol. Plants were grown in two-compartment pots, where the lower part was separated from the roots by monofilament gauze. Root hairs, but not roots, penetrated through the gauze into the lower part of the soil. The root-free soil in the lower compartment was either sterilized with cycloheximide and streptomycin or remained non-sterile. In order to investigate exudate distribution, 3 days after the 14C labeling, the lower soil part was frozen and sliced into 15, one-mm thick layers using a microtome. Cumulative 14CO2 efflux from the soil during the first 3 days after 14C pulse labeling did not change during plant growth and amounted to about 13–20% of the total recovered 14C (41–55% of the carbon translocated below ground). Nighttime rate of total CO2 efflux was 1.5 times lower than during daytime because of tight coupling of exudation with photosynthesis intensity. The average CO2 efflux from the soil with Zea mays was about 74 μg C g−1 day−1 (22 g C m−2 day−1), although, the contribution of plant roots to the total CO2 efflux from the soil was about 78%, and only 22% was respired from the soil organic matter. Zea mays transferred about 4 g m−2 of carbon under ground during 26 days of growth. Three zones of exudate concentrations were identified from the distribution of the 14C-activity in rhizosphere profiles after two labeling periods: (1) 1–2 (3) mm (maximal concentration of exudates) 2) 3–5 mm (presence of exudates is caused by their diffusion from the zone 1); (3) 6–10 mm (very insignificant amounts of exudates diffused from the previous zones). At the distance further than 10 mm no exudates were found. The calculated coefficient of exudate diffusion in the soil was 1.9 × 10−7 cm2 s−1.

A contribution of image processing to the diagnosis of diabetic retinopathy-detection of exudates in color fundus images of the human retina

In the framework of computer assisted diagnosis of diabetic retinopathy, a new algorithm for detection of exudates is presented and discussed. The presence of exudates within the macular region is a main hallmark of diabetic macular edema and allows its detection with a high sensitivity. Hence, detection of exudates is an important diagnostic task, in which computer assistance may play a major role. Exudates are found using their high grey level variation, and their contours are determined by means of morphological reconstruction techniques. The detection of the optic disc is indispensable for this approach. We detect the optic disc by means of morphological filtering techniques and the watershed transformation. The algorithm has been tested on a small image data base and compared with the performance of a human grader. As a result, we obtain a mean sensitivity of 92.8% and a mean predictive value of 92.4%. Robustness with respect to changes of the parameters of the algorithm has been evaluated.

Fusobacterium nucleatum in endodontic flare-ups.

The extent to which Fusobacterium nucleatum is recovered from root canals of teeth that present with an interappointment flare-up following endodontic instrumentation was investigated. Included in the study were 28 patients that sought emergency treatment after initiation of root canal therapy. Only non-painful teeth that had been treated because of a necrotic pulp and periapical inflammatory lesion were studied. Root canal samples for bacterial analysis were taken, transported to a bacteriological laboratory, and processed for a semiquantitative assessment of bacterial isolates. Bacterial findings were correlated with self-assessed pain intensity as recorded by means of a Visual Analogue Scale. Clinical presentation of swelling and presence of exudate in the treated root canals were also linked. Bacteria were recovered from all teeth examined. Gram-negative anaerobic coccoid rods (Prevotella species and Porphyromonas species) were frequent isolates. All teeth in patients who were reported to be in severe pain (Visual Analogue Scale > or = 6) displayed F nucleatum. Nine out of 10 of these teeth also had swelling and exudate in the root canals. Samples from the remaining patients that had teeth with less pain score showed a variable bacterial recovery. None of these teeth displayed F nucleatum. F nucleatum appears to be associated with the development of the most severe forms of interappointment endodontic flare-ups.

Antibiotics as an adjunct to phenol matrixectomy did not decrease healing time of ingrown toenails

(2000) Arch Fam Med 9, 930. Reyzelman AM, Trombello KA, Vayser DJ, et al. . Are antibiotics necessary in the treatment of locally infected ingrown toenails? . Sep/Oct; . :...

Effects of a fraction from maize root exudates on haploid strains of Sporisorium reilianum f. sp. zeae

Sporisorium reilianum f. sp. zeae is the causal agent of head smut of maize. Although the main symptom of this disease is the formation of a black fungal sorus on the reproductive parts of the maize, the infection always occurs via the roots. Early infection stages are characterised by a hyphal proliferation of the fungus around the roots. In this paper, we describe effects of a fraction extracted from maize root exudates on growth of S. reilianum f. sp. zeae. The fungus grew as a yeast form on artificial medium, but in presence of these fractions, some yeasts switched to a hyphal form. In addition, an increased proliferation of the yeast form was also observed with exudates from a variety of maize susceptible to head smut. In the presence of exudates obtained from a tolerant variety of maize, proliferation of the yeast form was inhibited, whereas the induction of yeast-hypha transition was always observed. These results indicated that some molecules in root exudates could play a role in the pre-infectious stage between maize and S. reilianum f. sp. zeae.

Sporulation of Phytophthora fragariae shows greater stimulation by exudates of non-mycorrhizal than by mycorrhizal strawberry roots

Arbuscular mycorrhizal fungi (AMF) show significant potential for biocontrol of Phytophthora spp., but there is little evidence for the mechanisms involved in the process. This study establishes that microorganism free exudates from roots colonised by AMF result in significantly less sporulation of P. fragariae than those from uncolonised plants. Experiments in vitro showed that after 48 h in the presence of exudates from strawberry roots colonised by Glomus etunicatum and G. monosporum, sporulation of P. fragariae was reduced by ca 67% and 64% relative to sporulation in the presence of uncolonised roots. After 72 h sporulation was reduced by 83% and 89% respectively. These data were then confirmed in an in vivo system in which Phytophthora fragariae was inoculated into the mycorrhizosphere of either uncolonised strawberry plants or those colonised by G. etunicatum. A similar trend was observed, with a 69% reduction in sporulation of P. fragariae after 72 h in the mycorrhizosphere of colonised plants relative to sporulation in the mycorrhizosphere of uncolonised plants.

Microbe-Mediated Germination of Ascospores of Monosporascus cannonballus

ABSTRACT Ascospores of Monosporascus cannonballus germinated readily in the rhizosphere of cantaloupe plants growing in field soil. However, little or no germination occurred in the rhizosphere of melon plants growing in field soil that was autoclaved prior to infestation with ascospores. The latter data suggested that root exudates alone do not stimulate ascospore germination and that the soil microflora may be involved in the induction of ascospore germination. Amending field soil with streptomycin (which inhibits gram-negative microorganisms) did not suppress ascospore germination in the rhizosphere of cantaloupe plants. However, amending the soil with penicillin (which inhibits gram-positive microorganisms) did suppress ascospore germination. Pentachloronitrobenzene (PCNB), which inhibits the gram-positive actinomycetes but does not inhibit gram-positive or gram-negative bacteria, also suppressed ascospore germination. These results suggest that actinomycetes, either directly or indirectly, are involved in the induction of ascospore germination in field soil in the presence of exudates from cantaloupe roots. Optimum germination occurred at temperatures ranging from 25 to 35 degrees C, and data indicate that a high percentage (>/=72%) of the ascospore population within 500 mum of a root are capable of germination and subsequent penetration of cantaloupe roots.

Morphological structure of the stigma and style of several genotypes of Prunus armeniaca L.

ABSTRACT The morphology of the stigmatic surface and style of apricot (Prunus armeniaca L.) is described, in order to extend current knowledge of stylar and stigmatic structures. Eight apricot cultivars of different geographical origin and characterised by a different self-compatibility behaviour were analysed. Whole pistils were removed from flowers at different phenological stages. Analyses were performed on frozen-hydrated specimens by Low-Temperature SEM. Morphological observations were conducted on: stigma (shape, size and presence of exudate), stigmatic papillae (shape, size, density and distribution) and style (inner structures). A comparative study of the different apricot cultivars showed several morphological differences related to the genotype.

Algal cyst dormancy: a temporal escape from herbivory

Many phytoplankton species form resting cysts and remain dormant for part of the year. The subsequent excystment is regulated by the external environment and internal maturation processes. Here we assessed the excystment of the dinoflagellates Ceratium hirundinella and Peridinium aciculiferum in relation to herbivores and temperature in laboratory and field studies. C. hirundinella, which has a grazer-resistant morphology, forms summer blooms, whereas P. aciculiferum, which is vulnerable to grazers, grows underneath the ice during winter. In our study, herbivore abundance, and thereby grazing pressure, was low during periods when water temperatures were low, and the abundance of P. aciculiferum was high. In the laboratory experiment, excystment of C. hirundinella occurred at high temperatures irrespective of whether zooplankton exudate was added or not, whereas at intermediate temperatures, excystment was lower if zooplankton exudate was added. Germination of P. aciculiferum cysts was lower in the presence of exudate from a zooplankton culture than in controls at all temperatures. Our studies suggest that dinoflagellates use the presence of zooplankton in addition to temperature as a cue to determine when to excyst. Consequently, not only abiotic factors, but also the composition of the food web, may determine succession and composition of phytoplankton communities.

A Novel Wound Dressing With an Antibiotic Delivery System Stimulated by Microbial Infection

The aim of this study was to develop a new wound dressing with controlled release of antibiotics only in the presence of inflection. In the first experiment using an infected dorsal pouch of rats, exudate containing proteinases from pouches contaminated with Staphylococcus aureus or Pseudomonas aeruginosa showed significantly higher hydrolytic activity toward Boc-Val-Pro-Arg-MCA than that from noninfected wounds. The authors then developed a new type of wound dressing (AGX), a drug delivery system in which gentamicin is bound to polyvinylalcohol hydrogel through an enzymatically degradable peptide linker containing a -(D)-Phe-Pro-Arg- sequence. To investigate in vitro effectiveness, AGX was incubated with exudate from S. aureus infected or P. aeruginosa infected wounds. Gentamicin was selectively released from AGX in the presence of the exudate from S. aureus infected or P. aeruginosa infected wounds, but was not released in the presence of exudate from noninfected wounds. Next, AGX or the polyvinylalcohol hydrogei that served as control was incubated with S. aureus in the presence of human plasma. After 24 hours, S. aureus concentration was markedly lower in the case with AGX than in that with polyvinylalcohol hydrogei. These results indicate that proteinases from wounds infected with S. aureus or P. aeruginosa cleaved the linker and gentamicin was released. ASAIO Journal 1997; 43:M854-M857.

A novel wound dressing with antibiotic delivery system stimulated by microbial infection

The aim of this study was to develop a new wound dressing with controlled release of antibiotics only in the presence of infection. In the first experiment using an infected dorsal pouch of rats, exudate containing proteinases from pouches contaminated with Staphylococcus aureus or Pseudomonas aeruginosa showed significantly higher hydrolytic activity toward Boc-Val-Pro-Arg-MCA than that from noninfected wounds. The authors then developed a new type of wound dressing (AGX), a drug delivery system in which gentamicin is bound to polyvinylalcohol hydrogel through an enzymatically degradable peptide linker containing a -(D)-Phe-Pro-Arg-sequence. To investigate in vitro effectiveness, AGX was incubated with exudate from S. aureus infected or P. aeruginosa infected wounds. Gentamicin was selectively released from AGX in the presence of the exudate from S. aureus infected or P. aeruginosa infected wounds, but was not released in the presence of exudate from noninfected wounds. Next, AGX or the polyvinylalcohol hydrogel that served as control was incubated with S. aureus in the presence of human plasma. After 24 hours, S. aureus concentration was markedly lower in the case with AGX than in that with polyvinylalcohol hydrogel. These results indicate that proteinases from wounds infected with S. aureus or P. aeruginosa cleaved the linker and gentamicin was released.

Defenses in phytoplankton against grazing induced by nutrient limitation, UV-B stress and infochemicals

It is becoming increasingly evident that the efficiency of zooplankton grazing on algae is not only a matter of quantity of the grazer relative to its food. Planktonic primary producers are not defenseless food-particles that are easily harvested by the consumers. Several algal species are able to adjust their phenotype (colony formation, spines, size) in such a way that it results in a reduced grazing pressure. It was recently demonstrated that morphological changes in the cell wall of green algae, induced by nutrient limitation and UV-B stress, may reduce their digestibility. A high fraction of induced cells pass intact and viable through the gut of the zooplankters, such that the grazing impact on the population is strongly reduced. It was also found that the presence of exudates (infochemicals) released by daphnids may change the morphology of algae. Unicellular green algae of the genus Scenedesmus were induced to form eight-cell coenobial types, heavily armed with spines, within three to five days after adding filtered water from an algal culture with Daphnia present. Both defence mechanisms may play an important role in zooplankton production and competition, and may serve as an example of highly efficient strategies to resist heavy grazing pressure.

Repellency of oral exudate to eastern and western spruce budworm larvae (Lepidoptera: Tortricidae)

A two-choice feeding bioassay was used to investigate the intra-specific repellency of the larval oral exudate of eastern and western spruce budworms,Choristoneura fumiferana (Clem.) andC. occidentalis Free., respectively. Results of the bioassay indicated that feeding behavior on artificial diet-drop feeding stations was modified in the presence of exudate, with feeding stations treated with conspecific exudate being avoided when an untreated station was available 3 cm away. Feeding was suppressed when a single, exudate-treated station was provided, or when the treated and untreated stations were separated by only 1 cm. The repellent effect functioned both inter- and intraspecifically. When induced to produce exudate,C. occidentalis larvae were not immediately repelled by either their own or other individuals' exudate. However, 24 hr after induction, test larvae were repelled by exudate from either source. In both species, larval oral exudate probably functions to repel conspecific competitors.

Antigenic Change in the Lipopolysaccharide ofRhizobiumef/iCFN42 Induced by Exudates ofPhaseolus vulgaris

Growth of Rhizobium etli CE3 in the presence of exudates from Phaseolus vulgaris resulted in a modified lipopolysaccharide (LPS) that no longer reacted with monoclonal antibody JIM28. However, the overall LPS structure appeared not to be greatly altered, as revealed by unchanged mobility in gel electrophoresis and partial or unaltered reactivity with other antibodies. Activity that triggered LPS antigenic conversion was exuded from both seeds and roots, but reactivity with one of the antibodies indicated that the resulting alterations were not identical. Antibody binding to the LPS decreased as a function of the concentration of exudate present during growth of the bacteria. The antigenic change did not occur if purified LPS or nongrowing bacteria were incubated with the exudates. Exudate-induced LPS modification did not require the Sym plasmid.

The use of intracerebral microdialysis for the determination of pharmacokinetic profiles of anticancer drugs in tumor-bearing rat brain.

The use of intracerebral microdialysis as a tool to measure the penetration of anticancer agents in brain tumor was investigated. Following intravenous (iv) administration of 75 mg/kg. concentration-time profiles of methotrexate (MTX) were determined in brain cortical dialysate and in plasma. The individual ratio of the area under the curve of MTX in brain dialysate over that in plasma (MTX penetration) was determined in normal brain, in tumor-bearing brain and in brain after sham tumor implantation. Individual brains were examined histologically on the presence of tumor, as well as for other factors that might influence local MTX penetration. Histological scores were related to the individual data on penetration of MTX. MTX penetration values were higher in cortical brain at the site of the tumor, as compared to the levels measured in normal or sham implanted brain (mean increase to 250%). In the cortical brain contralateral to the tumor, MTX penetration values were found to be lower than in normal brain (mean reduction of 65%). Furthermore, it appeared that in the absence of tumor tissue, the presence of exudate around the probe was independently associated with increased penetration of MTX into the brain. Tumor tissue appeared to be the most important parameter in changing local MTX penetration in brain after tumor implantation. In general, it is anticipated that intracerebral microdialysis combined with histological examination can be used to investigate effects of brain tumor presence on regional (periprobe) penetration of anticancer drugs into the brain.