On the Megasporogenesis in Chamaecyparis Lawsoniana Parl.

SUMMARYIn Chamaecyparis lawsoniana Parl, the megaspore mother cell (MMC) differentiates in the middle and innermost region of the nucellus as is generally the case in Gymnosperms. During its development the MMC attains a size much larger than that of the surrounding somatic cells and accumulates a considerable amount of food-storage substances. These consist of starch and droplets which could be, at least partly, of lipidic nature. During prophase I the MMC becomes a fully polarized cell since all or almost all the mitochondria are restricted to the chalazal cytoplasm. In the authors' opinion this is determined by the trophically privileged position of the chalazal cytoplasm. The polarization of the chondriome determines the course of the subsequent events in such a way that the meiotic divisions give rise to a linear triad, in which the two micropylar megaspores soon degenerate while the chalazal one inherits all of the mithochondria from the megasporocyte and remains functional. On the other hand the fo..

Observations on Certain Plastids of the Ovule of Ginkyo Biloba L.

SUMMARYAs reported in the literature for several groups of algae and for certain cells of higher plants, among which the endosperm (CAMEFORT and SCHAEFFER 1965) and the oosphere of Ginkyo biloba L. (CAMEFORT 1965), the authors observe that there is also often a contiguity between endoplasmic reticulum and plastids in the tapetum and in the central cell of the archegonium of this plant. The functional significance of this relationships is hypothesized. Moreover, the authors note that in the central cell and in the coenocytic pro-embryo the outer membrane of the plastidial wall bears some evaginations that extend into the cytoplasm. These evaginations seem, in certain cases, to connect two plastids in the central cell, for which it is thought that their formation is due to a particular scission process of the plastids themselves

ANGIOGENESI, INFIAMMAZIONE E FUNZIONE ENDOTELIALE IN DONNE IN POST MENOPAUSA AFFETTE DA SINDROME METABOLICA

Background: La prevalenza della sindrome metabolica (METS) aumenta dopo l’inizio della menopausa. Tuttavia non sono state ancora ben delucidate le concomitanti modificazioni del profilo vascolare, endoteliale e del processo infiammatorio. Obiettivo: Misurare marker specifici relativi all’angiogenesi, infiammazione e funzione endoteliale in donne in post-menopausa affette o meno dalla sindrome metabolica. Metodi: Sul siero di 100 partecipanti è stata valutata la concentrazione di Angiopoietina-2, Interleuchina-8 (IL-8), Ligando solubile di FAS (sFASL); Interleuchina-6 (IL-6), Tumor Necrosis Factor-α (TNF-α), Ligando solubile del CD40 (sCD40L), Inibitore-1 dell’attivatore del Plasminogeno (PAI-1), Attivatore urochinasi del plasminogeno (uPA). I confronti sono stati effettuati rispetto alla presenza o meno della Sindrome Metabolica e rispetto ai suoi specifici componenti. La presenza della sindrome metabolica è stata definita utilizzando i criteri diagnostici di Modified Adult Treatment Panel III Risultati: Il 57% (n=57/100) dei campioni di siero analizzati appartenevano a soggetti con Sindrome metabolica, il 47% (n=47) a individui sani. L’età e il tempo dall’inizio della menopausa era simile nei due gruppi. In generale le donne con la METS hanno mostrato una tendenza a elevati valori delle varie molecole analizzate. Nonostante questo, solo i livelli di IL-6 e quelli di uPA sono risultati rispettivamente più alti e più bassi, in maniera statisticamente significativa, nelle donne con la METS rispetto al controllo. Quando i valori degli analiti sono stati confrontati rispetto alla presenza delle singole componenti diagnostiche della METS è stato osservato che i livelli di IL-6 erano più alti fra le donne con obesità addominale, bassi valori di HDL-C e alti livelli di trigliceridi. Donne con ipertrigliceridemia e bassi livelli di HDL-C presentavano significative basse concentrazioni di uPA. Quelle con iperglicemia e bassi valori di HDL-C, invece, mostravano significativi alti livelli di sCD40L. Conclusioni: Nel nostro studio donne in post-menopausa con la METS hanno mostrato elevati livelli di IL-6 (infiammazione) e bassi livelli di uPA (disfunzione endoteliale) rispetto al controllo. Questi risultati sono principalmente connessi con alterazioni lipidiche e metaboliche. A questo proposito sono necessarie ulteriori ricerche. Background: Prevalence of the metabolic syndrome (METS) increases after the menopause; nevertheless, concomitant vascular, inflammatory and endothelial changes have not been completely elucidated. Objective: To measure serum markers of angiogenesis, inflammation and endothelial function in postmenopausal women screened for the METS. Methods: Serum of 100 postmenopausal women was analyzed for angiopoietin-2, interleukin-8 (IL-8), soluble FAS ligand (sFASL), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), soluble CD40 ligand (sCD40L), plasminogen activator inhibitor-1 (PAI-1), and urokinase-type plasminogen activator (uPA). Comparisons were made in accordance to the presence or not of the METS and each of its components. Modified Adult Treatment Panel III criteria were used to define the METS. Results: Women with the METS (n=57) had similar age and time since menopause as compared to those without the syndrome (n=43). In general, women with the METS displayed a trend for higher levels of the analyzed markers. Nevertheless, only IL-6 levels were found to be significantly higher and uPA levels significantly lower among METS women as compared to those without the syndrome. When analyte levels were compared as to presenting or not each of the diagnostic features of the METS, it was found that IL-6 levels were higher among women with abdominal obesity, low HDL-C and high triglyceride levels. Women with low HDL-C and high triglyceride levels presented significantly lower uPA levels and those with high glucose and low HDL-C displayed significantly higher sCD40L levels. Conclusion: Postmenopausal women with the METS in this sample displayed higher IL-6 (inflammation) and lower uPA levels (endothelial dysfunction). These were mainly related to metabolic and lipid abnormalities. More research is warranted in this regard

Connell and Slatyer's models of succession in the biodiversity era

Understanding how species interactions drive succession is a key issue in ecology. In this study we show the utility of combining the concepts and methodologies developed within the biodiversity–ecosystem functioning research program with J. H. Connell and R. O. Slatyer’s classic framework to understand succession in assemblages where multiple interactions between early and late colonists may include both inhibitory and facilitative effects. We assessed the net effect of multiple species interactions on successional changes by manipulating the richness, composition, and abundance of early colonists in a low-shore assemblage of algae and invertebrates of the northwestern Mediterranean. Results revealed how concomitant changes in species richness and abundance can strongly alter the net effect of inhibitory vs. facilitative interactions on succession. Increasing richness of early colonists inhibited succession, but only under high levels of initial abundance, probably reflecting the formation of a highly intricate matrix that prevented further colonization. In contrast, increasing initial abundance of early colonists tended to facilitate succession under low richness. Thus, changes in abundance of early colonists mediated the effects of richness on succession

Leccese sheep breed from Apulia: evidence of genetic substructuring from STR loci

Leccese is an originally triple-purpose sheep breed from Southern Italy. Due to major changes in rural society and livestock production, the breed has experienced in the last decades a drastic population size reduction. Nowadays roughly one thousand animals are reared in about ten farms located in Apulia. In order to evaluate the genetic variability within the Leccese breed, a total of 97 animals, sampled from five different farms in the provinces of Bari, Taranto, Brindisi, and Lecce were genotyped at 19 microsatellite loci belonging to the ISAG-FAO panel for Domestic Animal Diversity. Samples were chosen according to genealogical records in order to minimize relatedness among animals. Although being a local bottlenecked breed, the Leccese sample displayed a valuable number of alleles (187 over 19 loci, with a minimum of 4 in BM1824 and OarFCB193 and a maximum of 16 in MAF70 and MCM140). A high proportion of private alleles was observed for each farm (7.7 alleles on average). In addition, a high level of linkage disequilibrium was observed in the total sample, also among non syntenic locus pairs, suggesting the presence of population sub-structuring. To test the hypothesis of a genetic partitioning at the farm hierarchical level we first calculated the pair-wise FST between the different farms, which highlighted significant (P<0.001) though moderate values (0.055 to 0.065). Then, we performed both a likelihood-based and a Bayesian population assignment test, respectively implemented in the Arlequin and Structure software packages, in order to verify the degree of differentiation between the five farms. A correct allocation was obtained for 96.9% of animals by using the Arlequin software and 92.8% when using Structure, thus highlighting a clear genetic differentiation at the farm level, counterbalanced by a marked within-herd genetic similarity. These results suggest that reproductive isolation and/or different selection strategies across farms contributed to the observed pattern of genetic sub-structuring; this should be seriously taken into consideration, due to the critical implications for the breed conservation

Subtle differences in growth rate drive contrasting responses of ephemeral primary producers to recurrent disturbances

Although the importance of time after disturbance is well established in the ecological literature, studies examining how differences in growth rate affect species recovery and persistence in relation to the interval between recurrent perturbations are rare. We examined the response of two ephemeral primary producers inhabiting high-shore rock pools, epilithic microphytobenthos (EMPB), and green filamentous algae, to disturbance regimes varying for the time interval between consecutive events. Informed from an empirically parametrized growth model's outcomes, we tested the hypothesis that EMPB would be able to recover from more frequent disturbance compared with filamentous algae in a field experiment involving three physical disturbance patterns differing for the clustering degree: high, moderate, and low (20, 40, and 80 days between disturbances). We predicted that: high clustering would prevent the recovery of both taxa; moderate clustering would prevent the recovery of the slower growing taxon only (filamentous algae); both taxa would recover under low clustering. Results showed that EMPB persisted independently of the clustering degree, whereas filamentous algae did not withstand any disturbance regime. Dramatically different effects of disturbance on organisms with subtle differences in their growth rate indicate that even stronger responses may be expected from taxa with more markedly contrasting life histories

Effects of grazer diversity on marine microphytobenthic biofilm: a ‘tug of war’ between complementarity and competition

Species loss is one of the most striking problems related to human-driven environmental changes. Nevertheless, biodiversity and ecosystem functioning experiments have mainly focused on primary producers, paying less attention to the consequences of changing diversity at higher trophic levels. We performed a field experiment using cage enclosures to test the effects of species richness, identity and density of gastropod grazers on the photosynthetic efficiency and biomass of intertidal biofilm on an exposed rocky shore in the northwest Mediterranean. The diversity and composition of intertidal grazers affected the photosynthetic efficiency of biofilm with only negligible effects on biomass. Individual species showed strong identity effects. In assemblages of 2 or more species, positive or negative complementarity effects occurred. The magnitude of the ecosystem response is expected to depend on the particular species assemblage and its density, which will determine whether niche partitioning or competition is the prevailing process. Grazer preference in specific components of biofilm, characterized by different photosynthetic efficiency and competitive abilities, might explain concomitant changes in photosynthetic efficiency and comparable levels in biomass among treatments. The effects of grazers declined following the natural trend of decreasing biomass of biofilm during the study period, highlighting the importance of considering temporal variability in the effects of biodiversity on ecosystem functioning. This work emphasizes the key role of species identity to predict effects on their resources and ecosystem functioning.This work was partially supported by the University of Pisa

A new system for quantitative evaluation of infant gaze capabilities in a wide visual field.

Background: The visual assessment of infants poses specific challenges: many techniques that are used on adults are based on the patient’s response, and are not suitable for infants. Significant advances in the eye-tracking have made this assessment of infant visual capabilities easier, however, eye-tracking still requires the subject’s collaboration, in most cases and thus limiting the application in infant research. Moreover, there is a lack of transferability to clinical practice, and thus it emerges the need for a new tool to measure the paradigms and explore the most common visual competences in a wide visual field. This work presents the design, development and preliminary testing of a new system for measuring infant’s gaze in the wide visual field called CareToy C: CareToy for Clinics. Methods: The system is based on a commercial eye tracker (SmartEye) with six cameras running at 60 Hz, suitable for measuring an infant’s gaze. In order to stimulate the infant visually and audibly, a mechanical structure has been designed to support five speakers and five screens at a specific distance (60 cm) and angle: one in the centre, two on the right-hand side and two on the left (at 30° and 60° respectively). Different tasks have been designed in order to evaluate the system capability to assess the infant’s gaze movements during different conditions (such as gap, overlap or audiovisual paradigms). Nine healthy infants aged 4–10 months were assessed as they performed the visual tasks at random. Results: We developed a system able to measure infant’s gaze in a wide visual field covering a total visual range of ±60° from the centre with an intermediate evaluation at ±30°. Moreover, the same system, thanks to different integrated software, was able to provide different visual paradigms (as gap, overlap and audio-visual) assessing and comparing different visual and multisensory sub-competencies. The proposed system endowed the integration of a commercial eye-tracker into a purposive setup in a smart and innovative way. Conclusions: The proposed system is suitable for measuring and evaluating infant’s gaze capabilities in a wide visual field, in order to provide quantitative data that can enrich the clinical assessment