Studies in mycorrhizal and psuedomycorrhizal fungi from an experimental afforestation area

The investigations here described were carried out in connection with afforestation experiments at Wareham Forest, Dorset. The thesis consists of three papers. The first paper of the thesis deals with the mycelial and physiological characters of Boletus bovinus Linn, in pure culture, and with its growth reactions on such organic composts as are of interest in forestry practice. In connection with this, two types of mycorrhizal associations formed by Boletus bovinus with Pinus spp. at the experimental area, are described. The second paper is concerned with the cultural behaviour of several forms and strains of Mycelium radicis Melin, and with the description of various types and degrees of pseudo-myeorrhiza formation by this mycelium. Discussing the pathogenicity, attention is drawn to the fact that it is the proportion of pseudo-mycorrhizas and mycorrhizas formed by any individual tree which is of significance in respect to its general health. The third paper of the thesis deals with experiments and observations connected with analysis of the factors responsible for the suppression of growth in the experimental area. The anomalous features in the humus constituent of the experimental soil were studied by the effect of addition of cellulosic materials to this soil. The results obtained support the hypothesis that changes in the biological activities of the soil through addition of certain organic products have a direct effect on tree growth.<p

Molecular epidemiologic investigations of Mycoplasma gallisepticum conjunctivitis in songbirds by random amplified polymorphic DNA analyses.

An ongoing outbreak of conjunctivitis in free-ranging house finches (Carpodacus mexicanus) began in 1994 in the eastern United States. Bacterial organisms identified as Mycoplasma gallisepticum (MG) were isolated from lesions of infected birds. MG was also isolated from a blue jay (Cyanocitta cristata) that contracted conjunctivitis after being housed in a cage previously occupied by house finches with conjunctivitis, and from free-ranging American goldfinches (Carduelis tristis) in North Carolina in 1996. To investigate the molecular epidemiology of this outbreak, we produced DNA fingerprints of MG isolates by random amplification of polymorphic DNA (RAPD). We compared MG isolates from songbirds examined from 1994 through 1996 in 11 states, representing three host species, with vaccine and reference strains and with contemporary MG isolates from commercial poultry. All MG isolates from songbirds had RAPD banding patterns identical to each other but different from other strains and isolates tested. These results indicate that the outbreak of MG in songbirds is caused by the same strain, which suggests a single source; the outbreak is not caused by the vaccine or reference strains analyzed; and MG infection has not been shared between songbirds and commercial poultry

TCR Alpha LCR and non-LCR cis-elements contributing to tissue specific expression of the TCR Alpha gene in thymic and peripheral T cells

Orchestrated expression of multiple genes residing in the complex TCRα/δ/Dad1 locus requires tight control from multiple cis-acting elements. The TCRα locus control region (LCR), is positioned between TCRα and Dad1 gene, and has been implicated in the differential expression of both genes. In this study, we focus our work on the hypersensitive site (HS)1 prime (HS1\u27), located 3\u27 of the classical Eα enhancer, within the TCRα LCR. We investigated its non- redundant role in TCRα expression in thymic and peripheral T cells as assayed by in vivo and in vitro studies. Furthermore, formation of HS1\u27 in both lymphoid and non-lymphoid tissue raised the possibility of HS1\u27 playing a dual role in regulating both the upstream (TCRα) as well as the downstream (Dad1) genes. To answer this question, we created wild type and mutant HS1\u27 dual-reporter BACs utilizing human and rat CD2 reporter genes in the position of TCRα and Dad1, respectively. We find HS1\u27 important for TCRα expression in thymus and spleen T cells, but dispensable for Dad1 expression. We widened our focus to include sequences outside of the TCRα LCR. Specifically, DNase I hypersensitivity assay revealed a cluster of active chromatin just 5\u27 of the constant region Cα exons. Analysis of this 3.9-kb region using a BAC transgenic mouse model reveals its importance for TCRα gene expression in thymic and splenic T cells.Interestingly, this novel DNase hypersensitive regulatory complex will remain present upon the Vα-Jα rearrangement of the TCRα gene given its location 3\u27 of the most downstream functional joining (J) segment, Jα2. Therefore, the novel cis-acting region may contribute to endogenous TCRα gene activity

Characterization of in vivo-acquired resistance to macrolides of Mycoplasma gallisepticum strains isolated from poultry

The macrolide class of antibiotics, including tylosin and tilmicosin, is widely used in the veterinary field for prophylaxis and treatment of mycoplasmosis. In vitro susceptibility testing of 50 strains of M. gallisepticum isolated in Israel during the period 1997-2010 revealed that acquired resistance to tylosin as well as to tilmicosin was present in 50% of them. Moreover, 72% (13/18) of the strains isolated from clinical samples since 2006 showed acquired resistance to enrofloxacin, tylosin and tilmicosin. Molecular typing of the field isolates, performed by gene-target sequencing (GTS), detected 13 molecular types (I-XIII). Type II was the predominant type prior to 2006 whereas type X, first detected in 2008, is currently prevalent. All ten type X strains were resistant to both fluoroquinolones and macrolides, suggesting selective pressure leading to clonal dissemination of resistance. However, this was not a unique event since resistant strains with other GTS molecular types were also found. Concurrently, the molecular basis for macrolide resistance in M. gallisepticum was identified. Our results revealed a clear-cut correlation between single point mutations A2058G or A2059G in domain V of the gene encoding 23S rRNA (rrnA, MGA_01) and acquired macrolide resistance in M. gallisepticum. Indeed, all isolates with MIC ≥ 0.63 μg/mL to tylosin and with MIC ≥ 1.25 μg/mL to tilmicosin possess one of these mutations, suggesting an essential role in decreased susceptibility of M. gallisepticum to 16-membered macrolides

A Subsumption Agent for Collaborative Free Improvisation

This paper discusses the design and evaluation of an artificial agent for collaborative musical free improvisation. The agent provides a means to investigate the underpinnings of improvisational interaction. In connection with this general goal, the system is also used here to explore the implementation of a collaborative musical agent using a specific robotics architecture, Subsumption. The architecture of the system is explained, and its evaluation in an empirical study with expert improvisors is discussed. A follow-up study using a second iteration of the system is also presented. The system design and connected studies bring together Subsumption robotics, ecological psychology, and musical improvisation, and contribute to an empirical grounding of an ecological theory of improvisation

Binocular Rivalry in Children on the Autism Spectrum

When different images are presented to the eyes, the brain is faced with ambiguity, causing perceptual bistability: visual perception continuously alternates between the monocular images, a phenomenon called binocular rivalry. Many models of rivalry suggest that its temporal dynamics depend on mutual inhibition among neurons representing competing images. These models predict that rivalry should be different in autism, which has been proposed to present an atypical ratio of excitation and inhibition [the E/I imbalance hypothesis; Rubenstein & Merzenich, 2003]. In line with this prediction, some recent studies have provided evidence for atypical binocular rivalry dynamics in autistic adults. In this study, we examined if these findings generalize to autistic children. We developed a child-friendly binocular rivalry paradigm, which included two types of stimuli, low- and high-complexity, and compared rivalry dynamics in groups of autistic and age- and intellectual ability-matched typical children. Unexpectedly, the two groups of children presented the same number of perceptual transitions and the same mean phase durations (times perceiving one of the two stimuli). Yet autistic children reported mixed percepts for a shorter proportion of time (a difference which was in the opposite direction to previous adult studies), while elevated autistic symptomatology was associated with shorter mixed perception periods. Rivalry in the two groups was affected similarly by stimulus type, and consistent with previous findings. Our results suggest that rivalry dynamics are differentially affected in adults and developing autistic children and could be accounted for by hierarchical models of binocular rivalry, including both inhibition and top-down influences

Traditional and non-traditional treatments for autism spectrum disorder with seizures: an on-line survey

<p>Abstract</p> <p>Background</p> <p>Despite the high prevalence of seizure, epilepsy and abnormal electroencephalograms in individuals with autism spectrum disorder (ASD), there is little information regarding the relative effectiveness of treatments for seizures in the ASD population. In order to determine the effectiveness of traditional and non-traditional treatments for improving seizures and influencing other clinical factor relevant to ASD, we developed a comprehensive on-line seizure survey.</p> <p>Methods</p> <p>Announcements (by email and websites) by ASD support groups asked parents of children with ASD to complete the on-line surveys. Survey responders choose one of two surveys to complete: a survey about treatments for individuals with ASD and clinical or subclinical seizures or abnormal electroencephalograms, or a control survey for individuals with ASD without clinical or subclinical seizures or abnormal electroencephalograms. Survey responders rated the perceived effect of traditional antiepileptic drug (AED), non-AED seizure treatments and non-traditional ASD treatments on seizures and other clinical factors (sleep, communication, behavior, attention and mood), and listed up to three treatment side effects.</p> <p>Results</p> <p>Responses were obtained concerning 733 children with seizures and 290 controls. In general, AEDs were perceived to improve seizures but worsened other clinical factors for children with clinical seizure. Valproic acid, lamotrigine, levetiracetam and ethosuximide were perceived to improve seizures the most and worsen other clinical factors the least out of all AEDs in children with clinical seizures. Traditional non-AED seizure and non-traditional treatments, as a group, were perceived to improve other clinical factors and seizures but the perceived improvement in seizures was significantly less than that reported for AEDs. Certain traditional non-AED treatments, particularly the ketogenic diet, were perceived to improve both seizures and other clinical factors.</p> <p>For ASD individuals with reported subclinical seizures, other clinical factors were reported to be worsened by AEDs and improved by non-AED traditional seizure and non-traditional treatments.</p> <p>The rate of side effects was reportedly higher for AEDs compared to traditional non-AED treatments.</p> <p>Conclusion</p> <p>Although this survey-based method only provides information regarding parental perceptions of effectiveness, this information may be helpful for selecting seizure treatments in individuals with ASD.</p

Mapping of partially overlapping de novo deletions across an autism susceptibility region [AUTS5] in two unrelated individuals affected by developmental delays with communication impairment

Autism is a neurodevelopmental disorder characterized by deficits in reciprocal social interaction and communication, and repetitive and stereotyped behaviors and interests. Previous genetic studies of autism have shown evidence of linkage to chromosomes 2q, 3q, 7q, 11p, 16p, and 17q. However, the complexity and heterogeneity of the disorder have limited the success of candidate gene studies. It is estimated that 5% of the autistic population carry structural chromosome abnormalities. This article describes the molecular cytogenetic characterization of two chromosome 2q deletions in unrelated individuals, one of whom lies in the autistic spectrum. Both patients are affected by developmental disorders with language delay and communication difficulties. Previous karyotype analyses described the deletions as [46,XX,del(2)(q24.1q24.2)dn]. Breakpoint refinement by FISH mapping revealed the two deletions to overlap by approximately 1.1Mb of chromosome 2q24.1, a region which contains just one gene—potassium inwardly rectifying channel, subfamily J, member 3 (KCNJ3). However, a mutation screen of this gene in 47 autistic probands indicated that coding variants in this gene are unlikely to underlie the linkage between autism and chromosome 2q. Nevertheless, it remains possible that variants in the flanking genes may underlie evidence of linkage at this locus

Topiramate Monotherapy in Infantile Spasm

Infantile spasm is an age-related refractory epilepsy. Topiramate is a new anticonvulsant with multiple mechanisms of action, and it may be effective for treating pediatric epilepsies. To evaluate the efficacy and tolerability of first-line topiramate treatment for infantile spasm, 20 patients received topiramate monotherapy during this study. They were treated with an initial dose of 1 mg/kg/day, with a progressive titration of 1 mg/kg a week until their spasms were controlled and a maximum dose of 12 mg/kg/day was achieved. The evaluation of the treatment efficacy was based on the spasm frequency data that was obtained by the scalp and video-EEG, and by the parental count of spasm. Thirty percent of the subjects became spasm-free during the study. Six of 20 subjects (30%) had cessation of spasm and disappearance of hypsarrhythmia as seen via the video EEG; four (50%) of eight idiopathic patients had a response, whereas two (17%) of 12 patients with symptomatic infantile spasm responded. Seventy of the patients, including the spasm-free patients, had a reduction in their seizure frequency of more than 50%, and 10% of the patients had a reduction in their seizure frequency of less than 50%. The clusters of spasm frequency decreased from 10.6 ± 8.5 to 3.5 ± 1.4 clusters/day. Topiramate is effective and tolerated in those patients suffering from infantile spasm. Our results suggest that this drug should be considered as a new first-line drug for treating infantile spasm

Apraxia of speech and cerebellar mutism syndrome: a case study

Background Cerebellar mutism syndrome (CMS) or posterior fossa syndrome (PFS) consists of a constellation of neuropsychiatric, neuropsychological and neurogenic speech and language deficits. It is most commonly observed in children after posterior fossa tumor surgery. The most prominent feature of CMS is mutism, which generally starts after a few days after the operation, has a limited duration and is typically followed by motor speech deficits. However, the core speech disorder subserving CMS is still unclear. Case presentation This study investigates the speech and language symptoms following posterior fossa medulloblastoma surgery in a 12-year-old right-handed boy. An extensive battery of formal speech (DIAS = Diagnostic Instrument Apraxia of Speech) and language tests were administered during a follow-up of 6 weeks after surgery. Although the neurological and neuropsychological (affective, cognitive) symptoms of this patient are consistent with Schmahmann’s syndrome, the speech and language symptoms were markedly different from what is typically described in the literature. In-depth analyses of speech production revealed features consistent with a diagnosis of apraxia of speech (AoS) while ataxic dysarthria was completely absent. In addition, language assessments showed genuine aphasic deficits as reflected by distorted language production and perception, wordfinding difficulties, grammatical disturbances and verbal fluency deficits. Conclusion To the best of our knowledge this case might be the first example that clearly demonstrates that a higher level motor planning disorder (apraxia) may be the origin of disrupted speech in CMS. In addition, identification of non-motor linguistic disturbances during follow-up add to the view that the cerebellum not only plays a crucial role in the planning and execution of speech but also in linguistic processing. Whether the cerebellum has a direct or indirect role in motor speech planning needs to be further investigated