Spontaneous cortical activity reveals hallmarks of an optimal internal model of the environment     

Berkes P  Orbán G  Lengyel M  Fiser J 《Science (New York, N.Y.)》2011,331(6013):83-87

The brain maintains internal models of its environment to interpret sensory inputs and to prepare actions. Although behavioral studies have demonstrated that these internal models are optimally adapted to the statistics of the environment, the neural underpinning of this adaptation is unknown. Using a Bayesian model of sensory cortical processing, we related stimulus-evoked and spontaneous neural activities to inferences and prior expectations in an internal model and predicted that they should match if the model is statistically optimal. To test this prediction, we analyzed visual cortical activity of awake ferrets during development. Similarity between spontaneous and evoked activities increased with age and was specific to responses evoked by natural scenes. This demonstrates the progressive adaptation of internal models to the statistics of natural stimuli at the neural level.  相似文献   

A selective activity-dependent requirement for dynamin 1 in synaptic vesicle endocytosis     

Ferguson SM  Brasnjo G  Hayashi M  Wölfel M  Collesi C  Giovedi S  Raimondi A  Gong LW  Ariel P  Paradise S  O'toole E  Flavell R  Cremona O  Miesenböck G  Ryan TA  De Camilli P 《Science (New York, N.Y.)》2007,316(5824):570-574

Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. Unexpectedly, mice lacking dynamin 1 were able to form functional synapses, even though their postnatal viability was limited. However, during spontaneous network activity, branched, tubular plasma membrane invaginations accumulated, capped by clathrin-coated pits, in synapses of dynamin 1-knockout mice. Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity.  相似文献   

Influence of shearing on oxidative stress and some physiological parameters in ewes     

Giuseppe PICCIONE  Francesco FAZIO  Stefania CASELLA  Pietro PENNISI  Giovanni CAOLA 《Animal Science Journal》2011,82(3):481-485

The aim of the present study was to evaluate the effect of shearing on physiological and oxidative stress parameters in ewes. Twenty Comisana ewes were used and divided into two groups. Ten ewes were left unshorn as a control group (Group A) and 10 ewes were shorn (Group B). All measurements were taken before and after shearing, and repeated 8 h after shearing and 1, 2, 3, 4, 5, 10 and 15 days after shearing. Reactive oxygen species (dROMs), antioxidant barrier (oxy‐adsorbent), thiol antioxidant barrier (SHp) and packed cell volume (PCV) were assessed in blood samples collected by means of jugular venipuncture. Rectal temperature (RT), respiratory rate (RR) and heart rate (HR) were also measured. Two‐way repeated measures analysis of variance (ANOVA), followed by Bonferroni's test, was used for the assessment of significant effects due to shearing and time. The statistical analysis showed significant increases (P < 0.01) of dROMs, oxy‐adsorbent, SHp, and a significant decrease (P < 0.01) of RT and RR associated with time and shearing. Our results indicate that shearing causes a change in the ewe's homeostatic balance that leads to oxidative stress.  相似文献   

The diversity inVavilov's Mediterranean Gene Center     

Pietro Perrino 《Genetic Resources and Crop Evolution》1988,36(1):85-105

  相似文献   

High levels of genetic differentiation between Wolbachia-infected and non-infected populations of Folsomia candida (Collembola, Isotomidae)     

Francesco Frati  Ilaria Negri  Pietro P. Fanciulli  Marco Pellecchia  Vincenzo De Paola  Valerio Scali  Romano Dallai 《Pedobiologia》2004,48(5-6):461-468

The Gram-negative -Proteobacterium Wolbachia pipientis has been described as an obligate endosymbiont in many arthropod species, where it induces a variety of reproductive alterations, including parthenogenesis. Recently, this microorganism has also been detected in the parthenogenetic collembolan Folsomia candida. Here, we confirm the occurrence of the endosymbiont also in two Italian parthenogenetic populations of F. candida using ultrastructural (electron microscopy) and molecular (PCR screening on two bacterial genes) evidence. The strain isolated in the Italian populations has almost-identical gene sequences compared to that previously isolated in other populations of F. candida. In addition, we discovered a population of Folsomia cf. candida, which showed the presence of both males and females. This population is not infected by Wolbachia. A screening of two mitochondrial genes (COI and COII) showed that the bisexual population has high levels of genetic divergence in comparison with the parthenogenetic ones, even suggesting the possibility that it belongs to a different species. Furthermore, the remarkably high levels of genetic divergence between the two parthenogenetic populations suggests a possible influence of Wolbachia on inducing such differentiation, and, in the long term, speciation.  相似文献   

Impact of Land Use and Urban Runoff on the Contamination of the Sarno River Basin in Southwestern Italy     

Arienzo  Michele  Adamo  Paola  Rosaria Bianco  Maria  Violante  Pietro 《Water, air, and soil pollution》2001,131(1-4):349-366

A study was conducted to determine the contaminantlevel of the Sarno River basin, a small creek located insouthwestern Italy. Six sampling site locations were selected tocoincide with two previous studies conducted in 1975 and 1985 toprovide a basis for comparison. For each location, twelve sampleswere collected over the period October 1997–September 1998.Results indicated a degradation in river water quality, especiallynear the mouth. This was reflected by a dissolved oxygenconcentration of about 0.8 mg L^-1 near the urban areas ofScafati, Pompei and Castellamare of Stabia. At the same locations,BOD₅ and COD values were two to five times higher than theallowable regulatory maximum levels, respectively. About 4 kmfrom the headwaters, the average oxygen concentration was 4.7 mgL^-1, BOD₅ values were close to the standard limit (37 vs 40 mg L^-1), and COD values were above the standard limits(252 vs 160 mg L^-1). Highest concentrations were detectedduring peak tomato production. During this time, settleable solidswere also elevated, two to six times the regulatory standard.Coliform bacteria densities were found in excess of the standardlimits at all sites. Near the head of the river, mean fecalcoliform (22,571 MPN mL^-1) and streptococci densities (14,214 MPN mL^-1) surpassed the regulatory level of 120 and 20 MPN mL^-1, respectively, reflecting the input from the urbansettings of Sarno and agricultural fields. The heavy metaldissolved concentrations were low at all sampling sites. Most ofthe analyzed contaminants increased when comparend with 1985data. BOD₅ increased 5 to 10 times at sites near the urbansettings of Scafati, Pompei and Castellamare di Stabia, whereasCOD increases were twofold at all sites. A decline of chromiumlevels was observed due to the recent effective treatment ofwaste water from the tanning plants.  相似文献   

Collection of land-races of cultivated plants in South Italy, 1984     

Pietro Perrino  Karl Hammer 《Genetic Resources and Crop Evolution》1985,33(2):225-236

Summary In continuation of collecting missions in the last four years a further mission has been carried out in South Italy jointly by staff members of the Istituto del Germoplasma, Bari, and the Zentralinstitut für Genetik und Kulturpflanzenforschung, Gatersleben, in September 1984 for studying and collecting indigenous forms of cultivated plants and their wild relatives. 185 samples, mainly of cereals, vegetables and grain legumes have been collected. The material represents highly variable old land-races; this is especially true for wheat, oats, maize,Brassica spp., french beans and faba beans. In Sicily wildBrassica spp. have been collected and in some places introgression from wild into cultivatedBrassica races could be observed. The results of this mission increase our knowledge concerning the flora of cultivated plants of South Italy considerably and stress the necessity for continuing the exploration of plant genetic resources in this region.

---

Sammlung von Kulturpflanzen-Landsorten in Süditalien 1984

Zusammenfassung In Fortführung von Sammelreisen der letzten vier Jahre wurde eine weitere Reise in Süditalien gemeinsam von Mitarbeitern des Istituto del Germoplasma, Bari, und des Zentralinstituts für Genetik und Kulturpflanzenforschung, Gatersleben, im September 1984 unternommen, die dem Studium und der Sammlung indigener Formen von Kulturpflanzen und ihrer verwandten Wildsippen diente. 185 Proben, vor allem von Getreiden, Gemüsen und Körnerleguminosen, wurden gesammelt. Das Material besteht aus hochvariablen alten Landsorten, besonders von Weizen, Hafer, Mais, Kohlsippen, Gartenbohnen und Ackerbohnen. In Sizilien wurden Wildkohle gesammelt, und an einigen Stellen konnten Introgressionen von Wildin Kultursippen beobachtet werden. Die Ergebnisse dieser Sammelreise, die unsere Kenntnisse der Kulturpflanzenflora Süditaliens beträchtlich erweitern, unterstreichen die Notwendigkeit zur Fortführung der Exploration pflanzengenetischer Ressourcen dieses Gebietes.

---

1984

. 1984 . . 185 , , , ; ; , , , , , . , . , , .

  相似文献   

Report on a travel to the Socialist People's Libyan Arab Jamahiriya 1983 for the collection of indigenous taxa of cultivated plants     

Pietro Perrino  G. Battista Polignano  Karl Hammer  Christian O. Lehmann 《Genetic Resources and Crop Evolution》1984,32(2):197-206

  相似文献   

Sicilian wheat varieties     

Pietro Perrino  Dr. Karl Hammer 《Genetic Resources and Crop Evolution》1983,31(2):227-279

  相似文献   

Lettuce response to organic and phosphate fertilizers and root mycorrhization     

Luis Miguel Brito  Áurea Sampaio  Rui Pinto  Isabel Mourão  João Coutinho 《Journal of plant nutrition》2016,39(6):842-849

The response of lettuce to production system, organic and phosphate fertilizers and root mycorrhization, was evaluated in two pot trials with factorial treatment combination of: (i) soil type (from organic and from conventional production systems) and organic fertilizer (0, 2 and 4 t ha^?1) in the first trial; and (ii) mycorrhizal inoculation (mycorrhized and non-mycorrhized plants) and Gafsa phosphate (0, 100 and 200 kg P₂O₅ ha^?1) in the second. Lettuce growth decreased with increasing rates of the organic fertilizer because of its very high electrical conductivity (50.1 dS m^?1) and lack of maturation. However, the fertilizer harmful effects were minimized in the soil from organic production. The application of Gafsa phosphate significantly increased lettuce yield and nutrient uptake. However, for the highest rate of phosphate, mycorrhized lettuce yield decreased compared to non-mycorrhized lettuce, suggesting that high soil available P may have harmful effects on the activity of mycorrhizal fungi.  相似文献