Changes in long-range connectivity and neuronal reorganization in partial cortical deafferentation model of epileptogenesis.

Severe brain injuries can trigger epileptogenesis, a latent period that eventually leads to epilepsy. Previous studies have demonstrated that changes in local connectivity between cortical neurons are a part of the epileptogenic processes. In the present study we aimed to investigate whether changes in long-range connectivity are also involved in epileptogenesis. We performed a large unilateral transection (undercut) of the white matter below the suprasylvian gyrus in cats. After about 2 months, we either injected retrograde tracer (cholera toxin, sub-unit B, CTB) or performed Golgi staining. We analyzed distribution of retrogradely labeled neurons, counted dendritic spines in the neocortex (Golgi staining), and analyzed dendritic orientation in control conditions and after the injury. We found a significant increase in the number of detected cells at the frontal parts of the injured hemisphere, which suggests that the process of axonal sprouting occurs in the deafferented area. The increase in the number of retrogradely stained neurons was accompanied with a significant decrease in neocortical spine density in the undercut area, a reduction in vertical and an increase in horizontal orientation of neuronal processes. The present study shows global morphological changes underlying epileptogenesis. An increased connectivity in the injured cortical regions accompanied with a decrease in spine density suggests that excitatory synapses might be formed on dendritic shafts, which probably contributes to the altered neuronal excitability that was described in previous studies on epileptogenesis.

Identification and Distribution of Fungi Associated with Fairy Rings on Golf Putting Greens.

Traditional methods for identification of fairy ring fungi rely on the morphology of mature basidiocarps, which are ephemeral and often do not reach maturity on golf greens due to management practices. From 2007 to 2009, basidiocarps and soil samples were collected from 15 hybrid bermudagrass and 30 bentgrass greens exhibiting fairy ring symptoms in California, Florida, Hawaii, Illinois, Oklahoma, North Caroline, South Carolina, and Wisconsin. Genomic DNA was extracted from 122 unknown samples. Extractions were made from mycelium isolated from puffball or mushroom tissue, from mycelium isolated from a soil block, or through direct DNA extraction from infested soil. DNA also was extracted from 16 reference isolates. The internal transcribed spacer (ITS) region of ribosomal DNA was amplified and sequenced using the basidiomycete-specific primer sets ITS1f/ITS4b and Basid0001/2R. Phylogenetic trees were constructed with the neighborjoining algorithm, with nodes evaluated by bootstrap analysis. Most samples grouped into one of three clades corresponding to species within the family Lycoperdaceae: Arachnion album, Bovista dermoxantha, and Vascellum curtisii. Although over 60 different basidiomycetes have been associated with fairy rings in turfgrasses, relatively few species were found on golf putting greens in this study. Presently, DNA sequencing may be the most efficient method for attempting speciation of fairy ring fungi from infested soil.

Cirsimarin, a potent antilipogenic flavonoid, decreases fat deposition in mice intra-abdominal adipose tissue.

OBJECTIVE: We previously reported that the flavonoid cirsimarin exerts in vitro a strong lipolytic activity on isolated adipocytes. This study was therefore designed to evaluate in vivo the effects of cirsimarin on white adipose tissue (WAT) accretion in mice. METHODS: Male CD1 mice were injected daily with either vehicle (intraperitoneal (i.p.)) or cirsimarin (25 or 50 mg kg(-1) per day, i.p.) for 18 days. Mice were killed and fat pads weighted. Epididymal fat pads were used for cellularity measurement. Effects of cirsimarin treatment on lipolysis and lipogenesis in WAT were assessed. RESULTS: Mice treated with 25 or 50 mg kg(-1) per day cirsimarin showed a decrease in retroperitoneal (-29 and -37% respectively, P<0.005) and epididymal (-25 and -28% respectively, P<0.005) fat pad weights compared with controls. This effect was restricted to intra-abdominal WAT as no difference was noticed for subcutaneous inguinal WAT. The decrease in intra-abdominal WAT accretion was due to a decrease in adipose cell diameter (-5 and -8% for 25 and 50 mg kg(-1) per day cirsimarin, respectively) resulting in a 14 and 35% decrease in adipose cell volume while no change was noticed in total adipocyte number. Direct injection of cirsimarin (50 mg kg(-1)) to rats did not trigger lipolysis. In contrast, cirsimarin showed in vivo as well as in vitro a strong antilipogenic activity, which may be the critical aspect of its effects on fat accretion in mice. The inhibitory concentration 50% of cirsimarin on lipogenic activity in isolated adipocytes was found to be 1.28±0.04 µM. Cirsimarin given orally reduced intra-abdominal fat accretion in mice. CONCLUSION: Cirsimarin exerts potent antilipogenic effect and decreases adipose tissue deposition in mice. Cirsimarin could therefore be a potential candidate for the treatment of obesity.

A 3D slim-base probe array for in vivo recorded neuron activity.

This paper introduces the first experimental results of a new implantable slim-base three-dimensional (3D) probe array for cerebral applications. The probes are assembled perpendicularly into the slim-base readout platform where electrical and mechanical connections are achieved simultaneously. A new type of micromachined interconnect has been developed to establish electrical connection using extreme planarization techniques. Due to the modular approach of the platform, probe arrays of different dimensions and functionality can be assembled. The platform is only several hundred microns thick which is highly relevant for chronic experiments in which the probe array should be able to float on top of the brain. Preliminary tests were carried out with the implantation of a probe array into the auditory cortex of a rat.

Temporal and Spatial Epidemiology of Phytophthora Root Rot in Fraser Fir Plantations.

In 1999, 19 plots of Fraser fir (Abies fraseri) with a disease focus were established in commercial plantings grown for Christmas tree production in the mountains of five western North Caro-lina counties. Progress of Phytophthora root rot caused by Phytophthora cinnamomi as estimated by mortality was followed in each plot over 3 to 4 years in an attempt to understand dispersal of inoculum. Slope, aspect, and field production age at the time plots were established were recorded. Rainfall estimated from National Weather Service stations each growing season also was recorded. The relationship of site parameters and rainfall to dispersal and disease was investigated. Disease incidence and mortality were assessed in June and September each year for 3 or 4 years depending on plot. Phytophthora root rot as estimated by mortality counts over time in a logistic regression model progressed in only five of 19 plots over 3 years. None of the site parameters correlated with mortality data, although slightly more disease was found in plots with a north aspect. Rainfall was below normal in the 3 years of the study and did not correlate with mortality in any year. Lack of disease progress in the majority of plots was attributed to drought conditions in the region. In the five plots where mortality increased over time, spatial analysis suggested an aggregated pattern of diseased plants. Aggregation was apparent but not very strong among nearest neighbors, but was considerably stronger among groups of trees within a local area. This aggregation within groups was stronger when larger group sizes were examined by beta-binomial analysis. A spatial analysis by distance indices method (SADIE) indicated the presence of secondary clusters occurring several meters away from the main focus. A stochastic model also was employed that indicated a combination of spatial processes were likely involved, specifically a tendency toward spread within a local area, but not necessarily to the nearest neighboring trees, combined with an influence of background inoculum that could not be accounted for within local areas and may have come from external sources. Thus, all sources of inoculum including infected planting stock, inoculum in soil, infected trees, and contaminated equipment were equally important in epidemics of Phytophthora root rot in Fraser fir and dispersal of P. cinnamomi.

Stem Canker on Cotton Caused by Phoma exigua in North Carolina and Virginia.

Numerous reports about a disease of unknown etiology on cotton, Gossypium hirsutum L., in northeastern North Carolina and southeastern Virginia were received on 18 June 1999 following several days of cool weather with persistent mist and fog during the week of 14-19 June. Several fields were visited by consultants and county extension staff the following week. In some instances, the cotton stem was girdled, causing the upper portion of the plant to wilt and die. Cotton plants exhibiting various symptoms, including death, wilting, streaking of the vascular system, black sunken lesions on stems, and terminal necrosis were collected for examination and isolation. Pycnidia and spores of the fungus Phoma exigua were abundant in stem and terminal tissues. The fungus was isolated from infected stem tissue and cultured on PDA. A suspension containing 2.5 × 108 spores of P. exigua was sprayed on cotton leaves or injected into the stems to confirm pathogenicity. Controls were sprayed or injected with distilled water. Plants were placed in 100% humidity for 72 h and maintained in the greenhouse thereafter. The experiment was replicated five times and repeated once. Typically, streaking of the vascular system extended 1 to 5 cm from the point of stem inoculation. Inoculated cotton leaves had lesions resembling those attributed to Ascochyta gossypii. Reisolation of the fungus P. exigua from inoculated tissue on potato-dextrose agar (PDA) was successful in all treatments. Crossan (2) considered many isolates of Ascochyta taken from various hosts in North Carolina, including A. gossypii, to be synonymous with Ascochyta phaseolorum. A. phaselorum was subsequently synonomyzed with P. exigua (1). Ascochyta blight (also called ashen spot, or wet weather blight [4]) is usually a minor leaf spot caused by P. exigua (syn. Ascochyta gossypi) and is common in North Carolina. Stem canker caused by P. exigua has not been reported previously in North Carolina (3) or Virginia. The sunken canker at a node is the best diagnostic symptom for cotton stem canker. Dark streaks in vascular tissue extend below and above the canker but do not usually extend to the root system, as with wilt diseases. The disease was widespread and found in most fields north of I-40 in North Carolina into Virginia and east of I-95. Crop consultants and county extension staff estimated disease incidence in individual fields from less than 1 to over 90% in North Carolina and 6 to 25% in Virginia. Disease incidence did not appear to be affected by cotton cultivar, tillage, or crop rotation. This pathogen was also responsible for brittle cotton stems late in the season, resulting in boll loss. Proper identification of the causal organism is essential in formulating management strategies, since P. exigua has an extensive host range and rotation is unlikely to aid in management of this disease in the future. References: (1) G. H. Boerema. Ascochyta phaseolorum synonymous with Phoma exigua. Neth. J. Plant Pathol. 78:113-115, 1972. (2) D. F. Crossan. The relationships of seven species of Ascochyta occurring in North Carolina. Phytopathology 48:248-255, 1958. (3) L. F. Grand, ed. North Carolina Plant Disease Index. Tech. Bul. 240, 1985. (4) G. M. Watkins. Leaf spots. Pages 28-30 in: Compendium of Cotton Diseases, 1st ed. American Phytopathological Society, St. Paul, MN, 1981.

Incidence of Phytophthora Root Rot of Fraser Fir in North Carolina and Sensitivity of Isolates of Phytophthora cinnamomi to Metalaxyl.

A survey of Fraser fir Christmas trees in North Carolina for incidence of Phytophthora root rot was conducted during 1997 and 1998. Field sites (7- to 13-year-old trees) and nursery transplant beds (4- to 5-year-old trees) selected at random were surveyed based on foliar symptoms of Phytophthora root rot. Field sites were surveyed with a random transect method (>3,000 trees/field) or by counting all trees (<3,000 trees/field). Overall, incidence of Phytophthora root rot averaged 9% over the 58 field sites sampled, with a range of 0 to 75%. No relationship was found between number of years Fraser fir had been planted in the field site and disease incidence. Disease incidence did not increase as field sites were rotated through second or third crops of Fraser fir. Phytophthora spp. were recovered from 1.8% of asymptomatic trees sampled from 58 field sites across the state. P. cinnamomi accounted for 91% of the Phytophthora isolates recovered. In nursery transplant beds where a systematic sampling procedure was used, incidence of diseased trees averaged 2%, with a range of 0 to 12% across 16 locations. Recovery of Phytophthora spp. averaged 1.2% from root samples collected from 50 asymptomatic seedlings at each location. Isolates collected from the field and nursery transplant beds were grown on cornmeal agar incorporated with 0, 1, 1.25, 10, or 100 µg a.i. metalaxyl/ml. All 166 isolates of P. cinnamomi tested were sensitive to metalaxyl at 1 or 1.25 µg a.i. metalaxyl/ml. Although incidence of Phytophthora root rot has not increased in the state compared to a survey done in 1976 to 1977, the disease continues to limit production of Fraser fir in North Carolina.

First Report of the Telial Stage of Gymnosporangium exiguum on Ashe Juniper Adjacent to Hawthorn with Rust in Southwest Texas.

The telial stage of Gymnosporangium exiguum (2) on Ashe juniper (Juniperus ashei) was observed in Bandera County, TX, in April and May 1999 after rain events. Symptomatic plants with multiple lesions were found at low frequencies in dense J. ashei populations. Orange telia formed on scales and bark and on 2- to 3-mm-diameter twigs and became nearly inconspicuous when dry. No hypertrophy was observed. Previously reported telial hosts include J. californica and J. excelsa cv. Stricta in California; J. mexicana and J. scopulorum in Oklahoma; J. virginiana in Texas; and J. deppeana var. pachyphloea in Oklahoma and Texas (1). An aecial stage identified as G. exiguum has been observed for many years on native hawthorns (Crataegus crus-galli, C. greggiana, C. mollis, C. stevensiana, C. tracyi, C. turnerorum, C. viridis var. desertorum, and several natural hybrids) in Bandera, Bexar, Edwards, Gillespie, Kendall, Kimble, Real, and Uvalde counties, Texas. Prominent roestelioid aecia were observed on hawthorn leaves, petioles, fruits, peduncles, thorns, and, less often, on twigs. In two experimental plantings of hawthorns in Bandera County, rust severity was rated as low to moderate in six populations of C. greggiana and hybrids; moderate in two populations each of C. stevensiana and C. tracyi; moderate to severe in three populations of C. crus-galli and hybrids; and severe in one population each of C. mollis and C. viridis var. desertorum. G. exiguum was previously reported on a Crataegus sp. in Texas and on Heteromeles arbutifolia in California (1). Flowers, fruits, plant forms, and drought tolerances are characteristics of some endemic hawthorns that provide landscape and wildlife advantages. G. exiguum causing rust disease may limit the ornamental potential of highly susceptible hawthorn species in southwest Texas. Inconspicuous infections on susceptible ornamental Juniperus spp. also could have phytosanitary implications. Voucher specimens (aecia and telia) are on deposit in the Mycological Herbarium, Department of Plant Pathology, North Carolina State University, Raleigh. References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. (2) F. D. Kern. 1973. A Revised Taxonomic Account of Gymnosporangium. The Pennsylvania State University Press, University Park.

First Report of Thyronectria austroamericana Canker on Thornless Honey Locust in North Carolina.

Specimens from a thornless honey locust (Gleditsia triacanthos var. inermis 'Shade Master') with cankers were submitted in May 1999 to the North Carolina State University Plant Disease and Insect Clinic by staff from the North Carolina Zoological Park (Asheboro). Abundant stromata of Gyrostroma austroamericana, the anamorph of Thyronectria austroamericana, were associated with the cankers. A visit to the Zoological Park during August 1999 revealed seven additional honey locust trees with multiple branch and stem cankers and dieback. All infected trees had perithecia of T. austroamericana and/or its anamorph. The fungus is distinguished by the large clusters of yellow-brown perithecia with dark brown tips produced on stromata emerging from lenticels, elliptical muriform ascospores, and sparse ascoconidia (1,2). Ascoconidia form as the result of ascospores budding within the ascus. Other trees of the cultivar are an integral part of the landscaping theme of the African Pavilion of the park, and park staff were concerned about disease spread. Infected trees were 8 years old, and several had evidence of sunscald cankers, a common infection court of T. austroamericana (2). Thornless cultivars of honey locust are popular landscape plants in the central and eastern United States and may be seriously affected by T. austroamericana (2). Apparently 'Shade Master' is very susceptible to the fungus and should not be used as a landscape tree, especially where the disease has been reported. This is the first report of T. austroamericana in North Carolina on any host. Voucher specimens have been deposited in the National Fungus Collection, Beltsville, MD (BPI 74693), and in the Mycological Herbarium, Department of Plant Pathology, North Carolina State University, Raleigh. References: (1) E. V. Seeler, Jr. J. Arnold Arbor. Harv. Univ. 21:429, 1940. (2) W. A. Sinclair et al. 1993. Diseases of Trees and Shrubs. Cornell University Press, Ithaca, NY.

A case of tracheal fibrolipoma.

We report the case of a tracheal fibrolipoma in a 40-year-old man successfully treated by laser photocoagulation. The clinical and pathological aspects, as well as the therapeutical options of this rare upper airway benign tumor are discussed.

Radiation-induced augmentation of host resistance to histocompatible tumor in mice. Detection of a graft antitumor effect of syngeneic bone marrow transplantation.

Lethally irradiated and syngeneic bone marrow-reconstituted (C57BL/6JxDBA/2J) F1 female mice demonstrated prolonged survival following challenge with the DBA/2 mastocytoma P815-X2 compared with non-irradiated littermate controls. This radiation-induced augmentation of host resistance to P815-X2 was not abolished by the adoptive transfer of normal syngeneic spleen cells. In addition, this phenomenon was not detectable in adult thymectomized recipients, suggesting the requirement for an intact host thymus. This effect was also absent in syngeneic F1 male recipients. We suggest that lethal irradiation and marrow reconstitution may result in activation of a nonspecific immune effector mechanism against tumor cells--and, as such, may serve as a model to explore the graft-antitumor effect of bone marrow transplantation.

Growth, ectomycorrhizae and nonstructural carbohydrates of loblolly pine seedlings exposed to ozone and soil water deficit.

Loblolly pine (Pinus taeda) seedlings from three full-sib families were exposed to 0, 50, 100 or 150 ppb ozone (O(3)) (5 h/d, 5 d/week for 6 or 12 weeks). Soil water potential was maintained near pot capacity (-0.03 MPa) or soil was allowed to dry to approximately -1.0 MPa and resaturated. Chlorotic mottling and flecking of needles due to O(3) injury were observed for seedlings from all pine families. Soil water deficit lessened the intensity of O(3) symptoms, possibly due to stomatal closure. Exposure to O(3) and soil water deficit each resulted in less seedling volume growth and dry weight, and changed the nonstructural carbohydrate content of seedlings compared with controls. Increasing O(3) concentrations resulted in a linear reduction in foliar starch content but did and affect hexose or sucrose content. Soil water deficit resulted in less starch and soluble sugar contents in above- and below-ground plant parts compared with controls. Soil water deficit did not affect numbers or percentages of roots that formed ectomycorrhizal tips. A linear dose-response relationship between O(3) and ectomycorrhizae was observed. The number of ectomycorrhizal tips/cm long root and the percentage of feeder roots that formed ectomycorrhizae were lower as O(3) concentration increased. Overall, each stress alone caused less seedling growth and carbohydrate content compared with controls, but only O(3) was responsible for suppression of ectomycorrhizae.

Effects of simulated rain acidity on ectomycorrhizae of red spruce seedlings potted in natural soil.

Formation of ectomycorrhizae of red spruce (Picea rubens) grown in natural soil was measured after seedlings were exposed to 25 or 50 applications of simulated rain of pH 5.5, 3.5 or 2.5. Ectomycorrhizae were quantified as the total number of ectomycorrhizal tips per centimeter, and as the number of ectomycorrhizal tips for each morphotype and for Cenococcum geophilum. Rain solutions were applied to the soil alone, to foliage and stem alone, or to entire potted seedlings. Final soil pH was linearly related to rain solution acidity. Lower base saturation, calcium and zinc content, and higher exchangeable acidity were observed after pH 2.5 treatments if the soil was exposed. Rain solutions and the subsequent changes in soil characteristics did not affect the total numbers of ectomycorrhizal tips. Four morphotypes of ectomycorrhizae observed for these seedlings were unaffected by simulated rain. However, the numbers of ectomycorrhizal tips formed by C. geophilum tended to increase with rain solution acidity after 50 applications. Method of rain deposition did not affect ectomycorrhizae, suggesting both plant and soil mediated responses may favor certain mycobionts. The results of this study indicate that short-term acidic deposition does not induce significant changes in the frequency of ectomycorrhizae, but higher numbers of C. geophilum tips suggest there may be changes in the relative occurrence of specific morphotypes of fungus species.

Specific induction of erythroleukemia and myelogenous leukemia in Sprague-Dawley rats.

The experimental induction of leukemias of two sorts by two powerful chemical carcinogens was investigated in rats of a single strain. In Sprague-Dawley rats a series of intravenous injections of N-nitroso-N-methylurea selectively elicited myelogenous leukemia in high yields, whereas erythroleukemia was not evoked. Conversely, a set of intravenous injections of 7,8,12-trimethylbenz[a]anthracene specifically elicited erythro-leukemia in high incidence in the rats, whereas myelogenous leukemia was not produced.