Frammenti cotiledonari di Aesculus hippocastanum L. coltivati in vitro. Primi dati sul comportamento dell'amido e dell'escina

Abstract

Fragments of Aesculus hippocastanum L. cotyledons grown in vitro. First results about starch and aescin characteristic features.—Cotyledon fragments of Aesculus hippocastanum grown in vitro in different media have been able to form callus and roots. The starch granules in the new cells are compound in structure and morphologically different from the simple cotyledon granules, whereas they are similar to the granules of the other parts of the plant in toto. Moreover, the callus has no aescin even though it originates from the cotyledor tissues.     

A geostatistical model to describe root vitality and ectomycorrhization in Norway spruce

Abstract

The spatial distribution of vital root tips and ectomycorrhizal (ECM) communities in forest soils is characterized by patchiness at a microscale level, mostly related to the distribution patterns of biotic and abiotic factors. A geostatistical model was applied to verify if spatial analyses could be useful in identifying an appropriate sampling method to study root tip vitality, ectomycorrhization and the ECM community. Root samples were collected from two high mountain Norway spruce forests (Trentino province, Italy) following a geometrical design. Laboratory microscopic and geostatistical ordinary kriging analyses were used to map tip vitality and ectomycorrhization degree, ECM richness and distribution grouped in “exploration types” (amount of emanating hyphae or presence and differentiation of rhizomorphs). Spatial gradients of the examined features existed at plant level, associated to the up-downslope direction (root tip vitality and ectomycorrhization, ECM richness) and distance from the stem base (ECM exploration types). The effectiveness of the geostatistical model used demonstrates that a geometrical sampling design, associated to spatial mapping techniques, can be useful in research where the tree, and not the forest, is the subject (mycological and phytopathological studies).     

Tegumento seminale e germinazione in Cercis siliquastrum L.

Abstract

Seminal integument and germination of Cercis siliquastrum L. – A histological study of the seminal integument of Cercis siliquastrum L. has been carried out, in order to explain whether the obstacle to the germination, removed by a cold-treatment, was caused by a mechanical action of the integument itself. We have noted that both the cold-treated seeds which germinate and the non-treated control seeds which don't germinate show in the long run the same modifications. We have therefore come to the conclusion that the inability to germinate found in the non-treated seeds is not due to the mechanical resistance of the integument and we think it necessary to return to further researches, also at a biochemical level.     

L'Influenza Delle Condizioni Fotoperiodiche e Termiche Sull'Accrescimento e Riproduzione della Salvia Longistyla Benth

Summary

Observations on growth and development of Salvia longistyla Benth., in several photoperiodic and termoperiodic conditions, both natural and artificial, were performed. The conclusions of my work are the following

I° - It has been proved that Salvia longistyla is a typical short-day plant and that its critical point of reaction lies approssimately on the 14 hours, when the average night-temperature is about 18°C; the flowering does not succeed if the night-temperature is decidedly below 15°C.

II° - The plant' requires short-day conditions not only for the formation of the flower buds, but also for the subsequent development, i. e. the full bloom; consequently the plant belongs to Eguchi's S. S. class (short day-plant for both the manifestations).

III. - Under natural conditions, in our latitude, Salvia longistyla flowers only in Autumn, because only in this season we have suitable photoperiod and concomitantly suitable night-temperature. In Spring, though the day is short, the night-temperature is not sufficiently high; in Winter and in Spring, the flowering is possible only in a warm green-house, with a night-temperature of about 18°C. In orange green-houses Salvia longistyla can continue the flowering begun in Autumn; during Winter and Spring new blooms do not succeed, just because the night-temperature, in such green houses, is never sufficiently high.

IV. - We can obtain fruiting only by artificial pollination (lack of natural pollination agency).

V. - The basal branches do not flower even in optimal photo- and termoperiodical conditions (which allow apical flowering) on acount of a mechanism of correlative inhibition.

VI. - The elongation of the internodes is relatively inhibited at a very long photoperiod, differently from what we observe in most plants.

These prerogatives, verified in repeated experiments, are in perfect accordance with the characteristics of the ambient in which the plant is naturally diffused (Mexico). The altitude and latitude of the stations in which the plant has usually been found, have a short photoperiod all year long, and temperatures (also night-temperatures) costantly suitable for a good growth and bloom. The plants, in the natural ambient, are perennial and bushy. The pluri-annuality can be referred to the flowering inhibition of the lateral and basal branches, that takes place in a specimen and that keeps on for a long time, also after the full flowering of the principal axis. The basal shoots show a tendency to the vegetative growth, even though the external conditions are suitable to the flowering of the apical parts of the plant. Therefore we must attribute the pluriannuality of S. longistyla to this correlative flower-inhibiting mechanism.     

Anti-cyclic citrullinated peptide antibody titer predicts time to rheumatoid arthritis onset in patients with undifferentiated arthritis: results from a 2-year prospective study

Introduction

The diagnostic, predictive and prognostic role of anti-cyclic citrullinated peptide (CCP) antibodies in rheumatoid arthritis (RA) patients is widely accepted. Moreover, detection of these antibodies in subjects presenting with undifferentiated arthritis (UA) is associated with a significant risk to develop the disease. On the other hand, clinical and prognostic significance of evaluating anti-CCP levels in subjects with inflammatory arthritis at disease onset has not been fully clarified. The goal of this prospective study is to analyze the value and prognostic significance of anti-CCP titer quantification in UA subjects.

Methods

Serial anti-CCP assays were measured in 192 consecutive patients presenting with UA lasting less than 12 weeks. Clinical and serological data and arthritis outcome were evaluated every 6 months until two years of follow-up.

Results

Anti-CCP positivity, at both low and high titer, and arthritis of hand joints significantly predicted RA at two years, risk increasing in subjects with high anti-CCP titers at baseline. Moreover, time to RA diagnosis was shorter in patients with high anti-CCP2 titers at enrollment with respect to those with low antibody concentration.

Conclusions

Presence of anti-CCP antibodies, at both low and high concentration, is significantly associated with RA development in subjects with recent onset UA. However, time interval from the onset of the first symptoms to the fulfilment of the classification criteria appears to be directly related to the initial anti-CCP level.     

Effect of invader removal: pollinators stay but some native plants miss their new friend

Removal of invasive species often benefits biological diversity allowing ecosystems’ recovery. However, it is important to assess the functional roles that invaders may have established in their new areas to avoid unexpected results from species elimination. Invasive animal-pollinated plants may affect the plant–pollination interactions by changing pollinator availability and/or behaviour in the community. Thus, removal of an invasive plant may have important effects on pollinator community that may then be reflected positive or negatively on the reproductive success of native plants. The objective of this study was to assess the effect of removing Oxalis pes-caprae, an invasive weed widely spread in the Mediterranean basin, on plant–pollinator interactions and on the reproductive success of co-flowering native plants. For this, a disturbed area in central Portugal, where this species is highly abundant, was selected. Visitation rates, natural pollen loads, pollen tube growth and natural fruit set of native plants were compared in the presence of O. pes-caprae and after manual removal of their flowers. Our results showed a highly resilient pollination network but also revealed some facilitative effects of O. pes-caprae on the reproductive success of co-flowering native plants. Reproductive success of the native plants seems to depend not only on the number and diversity of floral visitors, but also on their efficiency as pollinators. The information provided on the effects of invasive species on the sexual reproductive success of natives is essential for adequate management of invaded areas.     

Efficient plasmid-mediated gene transfection of ovine bone marrow mesenchymal stromal cells

Background aimsGiven the close similarity between ovine and human cardiomyocytes, sheep models of myocardial infarction and heart failure are increasingly used in studies of stem cell-mediated heart regeneration. In these studies, mesenchymal stromal cells (MSCs) are frequently employed. To enhance the paracrine effects of these MSCs, ex vivo transfection with genes encoding growth factors has been proposed. Although viral vectors exhibit higher transfection efficiency than plasmids, they entail the risks of uncontrolled transgene expression and immune reactions that preclude repeated administration. Our aim was to optimize the efficiency of plasmid-mediated transfection of ovine MSCs, while preserving cell viability.MethodsVarying amounts of diverse cationic lipids were used to obtain the reagent-to-DNA mass ratio showing highest luciferase activity. Transfection efficiency (flow cytometry) was tested on plasmid-green fluorescent protein-transfected MSCs at increasing DNA mass.ResultsLipofectamine LTX 5 μL and Plus reagent 4 μL with 2 μg of DNA yielded 42.3 ± 4.7% transfection efficiency, while preserving cell viability. Using these transfection conditions, we transfected MSCs with a plasmid encoding human vascular endothelial growth factor (VEGF) and found high VEGF protein concentrations in the culture supernatant from day 2 (1968 ± 324 pg/mL per μg DNA) through at least day 12 (888 ± 386 pg/mL per μg DNA) after transfection.ConclusionsPlasmid-mediated transfection of ovine MSCs to over-express paracrine heart-regenerative growth factors is feasible and efficient and overcomes the risks and limitations associated with the use of viral vectors.