Auditory Processing in High-Functioning Adolescents with Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a pervasive developmental disorder including abnormalities in perceptual processing. We measure perception in a battery of tests across speech (filtering, phoneme categorization, multisensory integration) and music (pitch memory, meter categorization, harmonic priming). We found that compared to controls, the ASD group showed poorer filtering, less audio-visual integration, less specialization for native phonemic and metrical categories, and a higher instance of absolute pitch. No group differences were found in harmonic priming. Our results are discussed in a developmental framework where culture-specific knowledge acquired early compared to late in development is most impaired, perhaps because of early-accelerated brain growth in ASD. These results suggest that early auditory remediation is needed for good communication and social functioning.     

An optimised PCR/T-RFLP fingerprinting approach for the investigation of protistan communities in groundwater environments

Due to the scarcity or complete absence of higher organisms, protists may represent an important higher trophic level (above Prokaryotes) in the food webs of groundwater habitats. Nevertheless, the importance of aquifer protists, especially in contaminated groundwater environments, is poorly understood. Partly, this may be due to a lack of adequate PCR and fingerprinting approaches for protists in aquifers, which can be considered low in protistan or high in non-target rRNA gene copy numbers. Therefore, we have validated the suitability of distinct eukaryote-targeted primer pairs and restriction endonucleases for T-RFLP fingerprinting of protistan communities. By in silico predictions, and by fingerprinting, cloning and sequencing of microeukaryote amplicons from hydrocarbon-contaminated aquifer sediment DNA, we show that the Euk20f/Euk516r primer set in combination with Bsh1236I digestion is best suited for the recovery of diverse protistan 18S rRNA lineages. In contrast to other tested primer sets, a preferred recovery of fungal and archaeal non-target amplicons was not observed. In summary, we present an optimised microeukaryote-targeted PCR/T-RFLP fingerprinting approach which may be of value for the characterisation of protistan communities in groundwater and other habitats.     

Allelochemical interactions and short-term effects of the dinoflagellate Alexandrium on selected photoautotrophic and heterotrophic protists

The marine dinoflagellate genus Alexandrium (Halim) Balech contains members that produce highly potent phycotoxins (PSP toxins or spirolides) as well as lytic substances and other allelochemicals of unknown structure and ecological significance. One isolate each of six Alexandrium species (A. tamarense, A. ostenfeldii, A. lusitanicum, A. minutum, A. catenella, A. taylori), of the closely related gonyaulacoid dinoflagellate Fragilidium subglobosum, and of the peridinioid Scrippsiella trochoidea were tested in 24 h co-incubation experiments for their short-term deleterious effects on a diversity of marine protists. Both autotrophs (Rhodomonas salina, Dunaliella salina, Thalassiosira weissflogii) and heterotrophs (Oxyrrhis marina, Amphidinium crassum, Rimostrombidium caudatum) were included as target species. All donor isolates except S. trochoidea exhibited lytic effects on at least some target species. Lytic effects were observed with all Alexandrium species, for both whole cell samples and culture filtrate (<10 μm and <0.2 μm). Antibiotic treated cultures with drastically reduced bacterial numbers did not show any general reduction in lytic capacity, therefore direct involvement of extracellular bacteria in allelochemical production is unlikely. Values of EC₅₀, defined as the Alexandrium cell concentration causing lysis of 50% of target cells, differed by two orders of magnitude depending on the donor/target combination, from 3.1 × 10³ cells ml⁻¹ (A. minutum/O. marina) down to 0.02 × 10³ cells ml⁻¹ (A. catenella/D. salina). Within the array of nine donor Alexandrium/target combinations, variable ratios in EC₅₀ values between donor/target combination cannot be explained by quantitative differences in allelochemical production, but rather indicate qualitative differences in the composition of compounds produced by different Alexandrium strains. In conclusion, our study confirms the widespread lytic capacity within the genus Alexandrium, although allelochemical effects are not restricted to this genus. Allelochemical interactions mediated by such lytic substances may be significant in explaining the formation and maintenance of Alexandrium blooms through direct destructive effects on competing algae or unicellular grazers.     

Effect of acclimation temperature on routine metabolic rate in triploid salmonids

The objective of this research was to determine whether triploid fish differ from diploids in their routine metabolic rates across a range of acclimation temperatures. Sibling diploids and triploids were acclimated to 12, 15 and 18 degrees C (Atlantic salmon; Salmo salar) and to 9, 12 and 15 degrees C (brook charr; Salvelinus fontinalis) prior to experimentation. Routine metabolic rates were then determined three times over a two-month period. Triploids of both species had higher metabolic rates than diploids at lower temperatures, and lower metabolic rates than diploids at higher temperatures, demonstrating that triploids have different (i.e., lower) thermal optima than diploids. This likely explains prior observations of high mortality of triploids at chronically elevated, but sub-lethal, rearing temperatures for sibling diploids.     

Restrictive surgical approach to palliate angina in a patient with coronary three vessel disease and biventricular metastatic hepatocellular carcinoma

Background

Metastatic cardiac tumors may cause different symptoms including angina, symptoms of heart failure and/or arrhythmia. In patients with concomitant coronary artery disease, it may be difficult to distinguish between angina caused by metastases to the heart, for example, by stealing perfusion from the coronary arteries, and angina caused by coronary stenosis. Identifying the origin of the symptoms is, however, essential for designing appropriate surgical strategies.

Case presentation

A 69-year-old male with multifocal recurrence of a hepatocellular carcinoma (HCC) presented with increasing ventricular arrhythmia and angina several weeks after posterior myocardial infarction and PCI of the RCA culprit lesion during which two further lesions present in the distal RCX and a posterolateral branch, and a chronically occluded LAD had not been addressed. MRI showed a large metastatic tumor infiltrating the walls of both ventricles as well as the interventricular septum. His debilitating symptoms were attributed to steal phenomena and/or perivascular compression caused by the metastatic tumor rather than the remaining coronary lesions, and he was offered a restrictive surgical approach consisting of debulking of the metastasis with an option for subsequent coronary intervention. The palliative surgical procedure resulted in a reduction of the tumor mass by half and sufficiently reduced the patient’s symptoms so that further coronary intervention was not required.

Conclusions

Palliative surgery for metastases to the heart may benefit patients, provided that the origin of symptoms is identified correctly. It goes without saying that in a palliative setting, surgery should be limited to treating symptoms rather than performing extensive procedures addressing, for example, coronary artery or valve disease. Interventional cardiac procedures addressing not only CAD but also valve disease may supplement palliative tumor surgery.

     

A comparative approach to study inhibition of grazing and lipid composition of a toxic and non-toxic clone of Chrysochromulina polylepis (Prymnesiophyceae)

Since the massive bloom in 1988 in the North Sea, the prymnesiophyte flagellate Chrysochromulina polylepis Manton et Parke has been known for its ichtyotoxicity. Laboratory experiments using two different clones of C. polylepis were conducted in a comparative approach. Both clones were nearly similar in size and shape, but differed in their toxicity, as demonstrated by the Artemia bioassay. In order to study the effects of toxic C. polylepis on protozooplankton grazers, grazing experiments were performed with the heterotrophic dinoflagellate Oxyrrhis marina Dujardin as grazer. A first experiment was carried out in order to follow batch culture growth and initial grazing of O. marina when fed toxic or non-toxic clones of C. polylepis. Ingestion of the toxic clone was 27% of ingestion when fed with the non-toxic clone. When O. marina was fed with the toxic clone, vacuoles within O. marina contained fewer food particles per cell and the cells attained slower division rate (58% of the division rate estimated for the non-toxic clone). A second experiment was conducted to determine the grazing and growth response of O. marina as a function of algal food concentration. Profound differences in ingestion, clearance, division and gross growth efficiency of O. marina when fed the two clones of C. polylepis again were apparent. However, even at algal concentrations of 400×10³ ml⁻¹, O. marina is not killed by the presence or by the ingestion of toxic C. polylepis, indicating that the toxin deters grazers. In addition to grazing experiments, lipid classes and fatty acids of both algal clones were analysed and compared in order to follow the hypothesis that toxicity of C. polylepis is caused by liposaccharides, lipids, or fatty acids. However, the chemical composition with respect to lipid classes and fatty acids of both clones were quite similar, making an involvement of these substances in the toxicity towards Artemia and O. marina unlikely.     

Axial Differences in Community Structure of Crenarchaeota and Euryarchaeota in the Highly Compartmentalized Gut of the Soil-Feeding Termite Cubitermes orthognathus

Methanogenesis represents an important electron sink reaction in the hindgut of soil-feeding termites. This is the first comprehensive analysis of the archaeal community structure within the highly compartmentalized intestinal tract of a humivorous insect, combining clonal analysis and terminal restriction fragment (T-RF) length polymorphism (T-RFLP) fingerprinting of the archaeal communities in the different gut compartments of Cubitermes orthognathus. We found that the morphological and physicochemical heterogeneity of the gut is reflected in a large phylogenetic diversity and pronounced axial differences in the composition of the archaeal gut microbiota, notably among those clones or ribotypes that could be assigned to methanogenic taxa. Comparative analysis of the relative frequencies of different archaeal lineages among the small-subunit rRNA gene (SSU rDNA) clones and their corresponding T-RF indicated that the archaeal community in the anterior, extremely alkaline hindgut compartment (P1) consists mainly of members of the Methanosarcinaceae, whereas Methanobacteriaceae and Methanomicrobiales predominate in the subsequent, more posterior compartments (P3/4a and P4b). The relative abundance of Thermoplasmales increased towards the rectum (P5). SSU rDNA sequences representing Crenarchaeota, which have not yet been reported to occur in the intestinal tracts of arthropods, were detected in all gut sections. We discuss how the spatial distribution of methanogenic populations may be linked to axial heterogeneity in the physicochemical gut conditions and to functional adaptations to their respective ecological niches.     

A cDNA clone from Zea mays endosperm sucrose synthetase mRNA

A cDNA clone for maize endosperm sucrose synthetase of 62o nucleotide pairs length was obtained by cloning double stranded DNA obtained from the total maize endosperm poly(A) RNA in pBR322, and identifying the appropriate clone by hybrid-promoter translation. In Southern blotting to genomic BamHI-digested DNA, a single band only of approximately 20 Kb lights up, indicating that the sucrose synthetase gene is unique, or that closely linked copies are located on this DNA fragment.