Anticipatory Smooth Eye Movements in Autism Spectrum Disorder

Smooth pursuit eye movements are important for vision because they maintain the line of sight on targets that move smoothly within the visual field. Smooth pursuit is driven by neural representations of motion, including a surprisingly strong influence of high-level signals representing expected motion. We studied anticipatory smooth eye movements (defined as smooth eye movements in the direction of expected future motion) produced by salient visual cues in a group of high-functioning observers with Autism Spectrum Disorder (ASD), a condition that has been associated with difficulties in either generating predictions, or translating predictions into effective motor commands. Eye movements were recorded while participants pursued the motion of a disc that moved within an outline drawing of an inverted Y-shaped tube. The cue to the motion path was a visual barrier that blocked the untraveled branch (right or left) of the tube. ASD participants showed strong anticipatory smooth eye movements whose velocity was the same as that of a group of neurotypical participants. Anticipatory smooth eye movements appeared on the very first cued trial, indicating that trial-by-trial learning was not responsible for the responses. These results are significant because they show that anticipatory capacities are intact in high-functioning ASD in cases where the cue to the motion path is highly salient and unambiguous. Once the ability to generate anticipatory pursuit is demonstrated, the study of the anticipatory responses with a variety of types of cues provides a window into the perceptual or cognitive processes that underlie the interpretation of events in natural environments or social situations.     

Cytometry and flow cytometry of 4',6-diamidino-2-phenylindole (DAPI)-stained suspensions of nuclei released from fresh and fixed tissues of plants

Cytometry and flow cytometry were used to study characteristics of fluorescence of the DNA-DAPI complex in nuclei released from different fresh and formaldehyde-fixed pea ( Pisum sativum L. cv. Lincoln) tissues. The two methods of isolation are compared and discussed as well as their possible use for quantitative analysis of DNA in plant tissues. With fixed tissues it is possible to obtain a number of nuclei sufficient for the flow cytometric analysis, even using small amounts of plant tissue.     

Open-Face, Epoxy Embedding of Single Cells for Ultrathin Sections

Intact stamens of Tradescantia were fixed, dehydrated, and infiltrated with an epoxy resin. Each stamen was then put into a drop of resin on a microscope slide, which was transferred to the stage of a dissecting microscope so that individual hairs could be detached from the filament with fine tungsten needles. The detached hairs were transferred to drops of resin ca. 2 mm in diameter (6 or 7 in each of two rows) lying on a slide heavily coated with evaporated carbon. Polymerization was carried out in an oven until the resin attained a degree of viscosity that permitted orientation of the isolated hairs (by using a compound microscope) without their subsequent dislocation. When the small drops of resin had hardened after further polymerization, the positions of the hairs were marked by circumscribing the cells with India ink. The block was pried from the slide after rapid cooling with solid CO₂, and was then trimmed and sectioned. Cells suspended in culture medium were embedded in much the same way; they were centrifuged to obtain a pellet, which was fixed, dehydrated, and infiltrated. A small fragment of the pellet with a little resin was placed on a microscope slide, where the cells were dissociated under a dissecting microscope at ca. 100 × magnification. Individual cells were then picked up with tungsten needles and transferred to droplets of resin on a carbon-coated slide. The subsequent steps were similar to those described for the staminate hairs. Pieces of tissue in the 50-500 μ range were also handled by the foregoing technique. However, after infiltration they were put into large drops of resin on a slide coated with silicone mold-release rather than on a surface coated with carbon.     

Inhibition of elongation and H+ and K+ transport by the phosphodiesterase inhibitor aminophylline in plant tissue

Aminophylline, an inhibitor of cyclic nucleotide phosphodiesterase (EC 3.1.4.17), inhibits elongation and correlated H⁺ and K⁺ transport in embryos of Haplopappus gracilis and in pea internode segments. Moreover, the drug strongly inhibits the stimulation of these processes by fusicoccin and indole-3-acetic acid and reduces passive permeability of the membrane. The possible mechanisms of action of aminophylline are discussed.Abbreviations cAMP adenosine 3:5-cyclic monophosphate - FC fusicoccin - IAA indole-3-acetic acid - MES 2-N-morpholinoethanesulfonic acid - PDE cyclic nucleotide phosphodiesterase     

Contributo alla sistematica degli attinomiceti: XVII actinomices scabies (Thaxter) Waksman

Riassunto Gli autori studiano un ceppo di attinomicete che essi identificano comeA. scabies. Con l'occasione essi precisano le caratteristiche diagnostiche di questa specie secondo quanto risulta da un esame critico della bibliografia in argomento, mettendo in evidenza che i ceppi collezionati sotto questo nome nelle varie micoteche hanno spesso caratteristiche differenti. La base di questo equivoco è, nelle considerazioni degli autori, da trovare nel riferimento patogenetico, cioè, in altri termini, nel voler considerare la malattia dei tuberi scabbiosi come provocata da un'unica specie.Dopo aver dato le caratteristiche delle specie presentano il seguente quadro tassonomico: Actinomyces scabies (Thaxter 1890)Gussov (1914) emendamentoWaksman (1919)=Oospora scabies Thaxter (1890)Diagnosi: vedi pag. 273.Habitat: frequente nel Nord America; isolato per la prima volta in Europa daSpalla eComaschi da tuberi scabbiosi provenienti dalla Germania. Actinomyces scabies varietàanglica Baldacci eBoncompagni =Actinomyces scabies Thaxter emendamentoMillard eBurr.Differisce dalla specie per il micelio vegetativo grigio, il micelio aereo spiccatamente grigio e per il pigmento giallo diffuso nel substrato.Habitat: isole inglesi.

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Zusammenfassung Die Verfasser studieren einen Stamm von Actinomyceten, den sie alsActinomyces Scabies identifizieren. In diesem Zusammenhang stellen sie die diagnostischen Merkmale dieser Art fest, bei kritischer Berücksichtigung der Literatur. Sie stellen fest, dass die unter diesem Namen gesammelten Stämme in den verschiedenen Mycoteken oft verschiedene Merkmale besitzen.Der Grund dieses Missverständnisses liegt, nach den Verfassern, in der pathogenischen Beziehung, i.c., dass man die in den vom Schorf befallenen Knollen die Krankheit als von einer einzigen Art verursacht annehmen will.Nachdem sie die Merkmale der Art festgelegt haben, geben sie die folgende Classification: Actinomyces scabies (Thaxter 1890)Gussov (1914), verbessert von Waksman (1919)=Oospora scabies Thaxter (1890).Diagnose: sieh Seite 273.Habitat: in Nord America ziemlich verbreitet und in Europa das erste Mal vonSpalla undComaschi aus schorfigen Knollen aus Deutschland isoliert. Actinomyces scabies Varietätanglica Baldacci eBoncompagni=Actinomyces scabies Thaxter verbessert vonMillard undBurr.Er unterscheidet sich von der Art durch ein graues vegetatives Mycel, durch ein sehr deutliches graues Luftmycel und durch ein gelbes im Substrat verbreitetes Pigment.Habitat: in England.

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I precedenti Contributi sono stati integralmente pubblicati sugli Atti dell'Istituto Botanico di Pavia e, in riassunto, su questa Rivista.     

Sugarcane (Saccharum X officinarum): A Reference Study for the Regulation of Genetically Modified Cultivars in Brazil

Global interest in sugarcane has increased significantly in recent years due to its economic impact on sustainable energy production. Sugarcane breeding and better agronomic practices have contributed to a huge increase in sugarcane yield in the last 30?years. Additional increases in sugarcane yield are expected to result from the use of biotechnology tools in the near future. Genetically modified (GM) sugarcane that incorporates genes to increase resistance to biotic and abiotic stresses could play a major role in achieving this goal. However, to bring GM sugarcane to the market, it is necessary to follow a regulatory process that will evaluate the environmental and health impacts of this crop. The regulatory review process is usually accomplished through a comparison of the biology and composition of the GM cultivar and a non-GM counterpart. This review intends to provide information on non-GM sugarcane biology, genetics, breeding, agronomic management, processing, products and byproducts, as well as the current technologies used to develop GM sugarcane, with the aim of assisting regulators in the decision-making process regarding the commercial release of GM sugarcane cultivars.     

Praziquantel Treatment Decreases Schistosoma mansoni Genetic Diversity in Experimental Infections

Background

Schistosomiasis has a considerable impact on public health in many tropical and subtropical areas. In the new world, schistosomiasis is caused by the digenetic trematode Schistosoma mansoni. Chemotherapy is the main measure for controlling schistosomiasis, and the current drug of choice for treatment is praziquantel (PZQ). Although PZQ is efficient and safe, its repetitive large-scale use in endemic areas may lead to the selection of resistant strains. Isolates less susceptible to PZQ have been found in the field and selected for in the laboratory. The impact of selecting strains with a decreased susceptibility phenotype on disease dynamics and parasite population genetics is not fully understood. This study addresses the impact of PZQ pressure on the genetics of a laboratory population by analyzing frequency variations of polymorphic genetic markers.

Methodology

Infected mice were treated with increasing PZQ doses until the highest dose of 3×300 mg/Kg was reached. The effect of PZQ treatment on the parasite population was assessed using five polymorphic microsatellite markers. Parasitological and genetic data were compared with those of the untreated control. After six parasite generations submitted to treatment, it was possible to obtain a S. mansoni population with decreased susceptibility to PZQ. In our experiments we also observed that female worms were more susceptible to PZQ than male worms.

Conclusions

The selective pressure exerted by PZQ led to decreased genetic variability in S. mansoni and increased endogamy. The understanding of how S. mansoni populations respond to successive drug pressure has important implications on the appearance and maintenance of a PZQ resistance phenotype in endemic regions.