Osservazioni Sulle Infrastrutture di Anabaena Cycadinae E delle Cellule dei Tubercoli Radicali di Cycas Revoluta

Abstract

Observations on the infrastructures of ANABAENA CYCADINAE and of root-nodules cells of CYCAS REVOLUTA. — Light and electron microscope observations carried on the fine and ultrafine sections of root-nodules of Cycas revoluta, brought in evidence differences structural and infrastructural of cells. These differences concern mainly the modifications presented by reticulum endoplasmic which in middle-aged cells takes a fragmentary and vescicular aspect, and the mitochondria which, in the same cells, show short cristae starting by outside wall of the organul.

About the plastyds, I could bring in evidence that there is plenty of leucoplasts but the proplastyds are still numerous, as the cloroplastyds showing some development of the lamellar system and of grana. Plastyds green are present either in while nodules, either in the root-tops.

In no nodules it has been possible to point out the presence of bacteria while it has been possible to verify that Algae have some polymorphism of structure because the chromatoplasma may result essentially of tree different aspects, by me, indicated as reticular type (fig. 12), lamellar type (fig. 10) and type at mixed structure (fig. 11).     

Ricerche istochimiche e al micro scopio elettronico sui tubi malpighiani di Dacus oleae Gmel.

Summary The Dacus oleae larva possesses four Malpighian tubules, two anterior and two posterior ones, which in pairs enter into a ureter. Before opening into the gut, at the level of the transition zone between the mid- and hindgut, each ureter is dilated into an ampulla.The anterior tubules are divided into four regions: distal, transition, middle and proximal ones: while in the posterior tubules only middle and proximal segments are detectable. The distribution of the enzyme systems is indicated in Fig. 3, while the ultrastructural organization which is typical of the cells composing the different regions is schematically represented in Fig. 1. According to the ultrastructural and enzymatic findings, and the discussion on this subject in the literature, the authors are led to assume that in the distal segment occurs the segregation of uric acid, urates and calcium salts. In the transition segment, and still more in the intermediate one, an indiscriminate transport of water and solutes occurs from the haemocoel into the lumen of the tubule by pinocytosis. A fraction of the catabolites is precipitated as chromolipoidal pigments. The transition stages between cytosomes and pigment are described. Along with secretory phenomena the resorption of useful substances occurs in the proximal region. A similar function is performed by the ureter. In the ampulla, which is characterized by a conspicuous system of deep tubular infoldings both at the apical and basal surfaces of its cells, a massive water resorption is presumed to occur.     

Ricerche sui pigmenti fotosintetici di Gracilaria verrucosa (Huds.) Papenfuss. Dosaggio quantitativo della ficoeritrina

Abstract

Research on photosynthetic pigments from Gracilaria verrucosa (Huds.) Papenfuss. Quantitative analysis of phycoerythrin. – Among biliproteins of Rhodophycean algae, phycoerythrin is very interesting for constant distribution, in large amounts, in the different species. Phycoerythrin's extinction coefficients have been already calculated for some Bangiophycean and only two species of Rhodophycean algae. In this work we have analyzed all photosynthetic pigments and isolated pure phycoerythrin from Gracilaria verrucosa (Huds.) Papenfuss [= Gracilaria confervoides (L.) Grev.] belonging to Gigartinales. The aim of our research was to evaluate the quantitative ratio between this pigment and the others in a sistematic group for which there are only qualitative data. Phycoerythrin of Gracilaria is the R-classical type, with three absorption maxima. Average values of absorption coefficients, calculated on a large number of samples are E₁ ^%cm (565 nm) = 53.8, E₁ ^%cm (540 nm) = 48.4, E₁ ^1%cm (498 nm) = 49.1. These values are different from those obtained for R-phycoerythrin of Ceramium rubrum and B-phycoerythrin of Rhodochorton floridulum, both species belonging to Floridean algae. Our several experiments by chromatography and gel-electrophoresis process have demonstrated that the R-phycoerythrin we isolated is substantially pure. Thus we suggest that different absorption coefficient values are due either to a more complicated protein in the pigment molecule or to a different chromophore/protein ratio. This could result very interesting for the chemotaxonomic and phylogenetic aspect, but the small number of algae till now analyzed does not allow to draw any general conclusion.     

Ricerche Sul Movimento Degli Stami in Alcune Berberidacee

Riassunto

L'A. studia i movimenti degli stami di Berberis in natura: trova che nel bocciolo i movimenti sono dovuti a fatti di diversità di accrescimento e di evoluzione dei singoli tessuti: determina il momento e le condizioni fisiologiche in cui si iniziano e la sensibilità e le proprietà contrattili (movimento rapido): mediante osservazioni di tipo sperimentale prova che il movimento rapido di contrazione e quello lento di estensione non dipende da relazioni umorali o di altro genere tra il filamento e gli altri organi del fiore ma è unicamente proprietà intrinseca della cellula contrattile: basandosi su questo fatto e sui dati ottenuti negli altri lavori riporta ad un unico schema i vari movimenti che lo stame compie da quando ha acquistato la proprietà contrattile fino al suo distacco dall'asse fiorale.     

Ricerche sui microrganismi produttori della fioretta nel vino

Zusammenfassung Aus 54 italienischen Weinproben mit Kahmhaut wurden 119 Reinkulturen isoliert, die aus den sporenbildenden Hefen Zygopichia chiantigiana Castelli, Pichia Derossii Castelli, Pichia membranae faciens Hansen sowie einer neuen Varietät dieser Art, var. acidificans, bestanden. Ferner fanden sich die nicht sporenbildenden Hefen Mycoderma cerevisiae Desmazières, M. Lafarii Janke, M. vini De'Rossi, M. acidificans De'Rossi, M. tenax De'Rossi, M. duplex De'Rossi und eine neue Varietät dieser Art, var. degradans. Ferner wurden noch acht nicht bestimmbare Mycoderma-Stämme gefunden und beschrieben. Alle festgestellten Formen unterscheiden sich stark in ihrer Fähigkeit zum Alkoholverbrauch und der Säurebildung.     

Ricerche sui rapporti endocrini fra il pancreas e l'ovaio

Zusammenfassung Die Resultate der wenigen Versuche über die Einwirkung von Insulin auf den Eierstock vorweggenommen, deutet der Verf. die interessantesten Data der experimentellen Pathologie und die klinischen Beobachtungen über die Beziehungen der inneren Sekretion der Bauchspeicheldrüse und des Eierstockes.Der Verf. hat erwachsene Ratten einer längeren Insulinbehandlung unterworfen und in diesen Tieren eine temporäre, über 6 Monate lang anhaltende, Sterilität erzielt.Der mikroskopische Befund der untersuchten Eierstöcke wies die Anwesenheit einer großen Zahl von Corpora lutea auf; im Restteil des Ovarparenchyms, das wie in die Zwischenräume zwischen den verschiedenen Corpora lutea verbannt erschien und nur wenige Gefäße aufwies, konnte man nur wenige Follikel kleiner und mittlerer Größe erblicken, deren einige in luteiniger Umbildung, andere von einer hohen Schicht zusammengepreßter Zellen umgeben waren, die sich tief färbten; eine derartige Verdickung, wenn auch in kleinerem Ausmaße, ließ sich auch rund um die wenigen primären Follikeln beobachten; die einzelnen Eizellen erschienen normal. Derartige histologische Veränderungen erklären es dem Verf. nach genügend, warum das Weibchen nicht befruchtet werden kann, wenigstens für eine gewisse Zeit; es erscheint daher überflüssig, nach anderen Hypothesen zu greifen, wie es einige Verf. getan, um die sterilisierende Wirkung des Inkrets der Bauchspeicheldrüse zu erklären.Verschiedene Hypothesen, teils auf Grund der neuesten Errungenschaften der diesbezüglichen Forschungen, werden vom Verf. bei der Frage des Wirkungsmechanismus des Insulins einer eingehenden Kritik unterworfen.Es wird an erster Stelle auf die Analogie im Verhalten zwischen dem Insulin und dem wässerigen antihypophysären Extrakt, was die Auswirkung am Eierstock anbetrifft, eingegangen; es wird nicht ausgeschlossen, daß das Insulin, bei Vermittlung der Hypophyse, die durch das Insulin selbst in ihrer Aktivität verstärkt würde, wie dies in der neuesten Zeit angenommen wird, einen indirekten Einfluß ausüben könne, wenn auch die Wirkung einzelner Corpora-lutea-Extrakte der des Insulins näherstehend erscheinen könnte.Die Hypothese, die der Verf. formulieren zu können glaubt und die u. a. die einfachste und die logischeste zu sein scheint, besagt, daß das Insulin die massenweise luteinige Umbildung der Ovarfollikel hervorruft, da dieses Insekret, das sichtliche Analogien mit dem Follikulin aufweist, in übermäßiger Menge in den Organismus eingeführt, in den Versuchen der Hyperhormonisierung mit dieser Substanz, ähnlich dem Follikulin sich auswirken könnte.     

Modificazioni Anatomiche ed Istologiche in Apici Radicali di Plantule di Pinus Pinea L. Germinate in Vitro al Buio da Semi Immaturi

Abstract

Histological and anatomical modifications in the root apex of PINUS PINEA L. seedlings grown in vitro from immature seeds, in the dark. — The seeds of Pinus pinea L. take three years to develop reaching maturity during the spring of the forth year. Immature seeds were collected at successive stages and cultivated in vitro in Heller's medium. The seedlings showed atrophy of the root togheter with histological and anatomical modifications of the root apex and formation of a small tuber. The extent of these modifications depends on the age of the seed and on how long the seedling is cultivated in vitro.

Seedlings derived from seeds planted on August 31st and kept in vitro for about a month had an atrophic root through lack of meristematic capacity; in it the secretory and conducting apparatuses had developed but with mixed radical and hypocotilar characters.

Seedlings from unripe seeds planted on September 30th and kept in culture for about one month showed an atrophic root owing to a rapid process of differentiation accompanied by the formation of isolated tracheid-like elements and of discontinuos vascular strands very near to the apex. Lateral proliferations gave rise to masses of various size of unorganised parenchyma which could separate the cortical and cap parenchyma from the central cylinder. In some cases the root cortex, clearly recognisable owing to an advanced process of differentiation, cut off from the central cylinder the root cap cells which degenerated.

Seedlings obtained from seeds planted on October 11th and kept in culture for about one month showed a radical tubercle deriving from fasciation of the main axis which had ceased growing and had formed various abnormal lateral root primordia.     

Effetto Dell'attinomicina Sulla Crescita di Alcune Specie di Alghe

Abstract

Action of Actinomycin on the growth of Algae. — Actinomycin C inhibits the growth of two strains of Euglena gracilis, of Chlorella vulgaris, of Prototheca zopfii and of Scenedesmus sp. The growth inhibitory effect is evident on both autotrophically and heterotrophically grown cultures. DNA extracted from C. vulgaris appears to form a complex with Actinomycin C similar to that observed in the case of other organisms.     

Ricerche Sull'ultrastruttura dei Tubi Cribrosi di Piccioli di Foglie di Edera

Abstract

The ultrastructure of sieve tubes in leaf petioles of HEDERA HELIX. — The structural organization of the sieve elements in Hedera leaf petiole at the beginning of the second year of life has been studied. At this stage of life the sieve tubes are completely developed, but still in full activity.

Their plasmatic structures, though altered, show that they are still alive. The cytoplasm forms a parietal layer; mitochondria, endoplasmic reticulum and plastids are present although very peculiar in aspect. The cytoplasm is bounded externally by a plasmalemma; on the contrary no tonoplast is detectable.

The data reported in this paper are favourable to the idea of an active partecipation of the sieve tubes in the translocation of organic solutes, in agreement with the findings concerning the oat coleoptile.     

Ricerche Sui Fenomeni di Contrazione di Mitocondri Isolati di Internodio di Pisello

Abstract

Study on the contraction phenomena of isolated mitochondria of pea internodes. — The action of the phosphorylative inhibitors atractylate and oligomycin on ATP-induced contraction of isolated pea mitochondria has been studied. Oligomycin has proved to be an efficient inhibitor of mitochondrial contraction; no effect is seen on the contrary upon addition of atractylate. Both atractylate and oligomycin inhibit completely oxygen consumption of mitochondria with succinate as substrate. On the base of these results it is postulated that the two inhibitors act upon different sites of the phosphorylative reaction sequence.     

Ricerche Sull'infrastruttura del Coleottile di Avena

Abstract

Researches on ultrastructure of Avena coleoptile. 3. The sieve elements. — A study on the ultrastructural organization of the mature sieve elements of Avena coleoptile has been carried out. Data suggest that functional phloem tubes are alive and remain alive until they are working. Judging on morphological basis, the metabolic activity of sieve elements should be of peculiar type and low in comparison to that of the companion cells. In fact the cytoplasm is located in a narrow parietal strand, mitochondria, Golgi apparatus and endoplasmic reticulum are present, but they appear very modified; plastids and nucleus are absent. The cytoplasm is bounded externally by a normal plasmalemma, whilst the vacuole has no visible limits: a tonoplast is, therefore not identifiable.

The strands connecting the superimposed sieve elements with one another through the sieve plate result to be made by a double membrane system very similar to the endoplasmic reticulum, which we believe to realize cytoplasmic continuity between phloem tubes.

The data reported are more favorable to the existence in the sieve tubes of an active mechanism of translocation of organic solutes than a passive mass-flow.

The collaboration of companion cells in the translocation mechanism has been discussed.     

Ricerche morfologiche ed istochimiche sui lipidi nel pancreas dei mammiferi

Con 10 figure nel testo.     

L'osmo-Resistenza di Dunaliella Salina Ricerche Ultrastrutturali

Abstract

The resistance of DUNALIELLA SALINA TO OSMOTIC STRESSES. ULTRASTRUCTURAL RESEARCHES. — The mechanisms which confer to Dunaliella salina its high resistance to osmotic stresses have been studied from a cytological point of view. For this purpose the Authors have examined the ultrastructural changes following a great rise or fall in the osmolarity of the normal culture medium.

When the tonicity of the nutrient medium is suddenly lowered the response of the alga is given by an instantaneous and general swelling. The whole cell and the single cytoplasmic structures appear equally swollen and the state of dispersion of the stroma of cellular organelles is highly increased. This shows clearly that a conspicuous amount of water has penetrated in every part of cell and suggests that the plasmatic cell membrane and the inner cytoplasmic boundaries may be considered as semipermeable membranes. The response of the different cellular organelles to a hypertonic shock is not quite identical; the mitochondria show for example a quite uniform type of swelling which does not alter deeply their morphological aspect, whilst in the inner space of the nuclear envelope wide sacks appear suggesting that the outer layer of the double membrane of the nucleus may be more permeable to water than the inner one. In the chloroplasts the flattened sacks formed by paired lamellae having blind endings in the peristromium swell up giving rise to conspicuous vesicles. This proves that the permeability to water of the lamellae is greater than that of the external plastidial boundary.

A sudden and strong hypertonic stress causes a great loss of water from every part of the cell. The alga appears indeed shrunken and shrinking phenomena can be see in all cytoplasmic organelles together with a greater electron density of their stroma. The two layers of the nuclear membrane and the lamellar pairs forming the sacculi in the chloroplasts stick closely together causing a nearly total disappearance of the inner space. This shows that the formation of large vesicles after a sudden hypotonic shock is really due to a different permeability of the two layers of the membrane and not to localised osmotic gradients.

In both cases the quite conspicuous structural variations appear reversible and the alga returns to the normal aspect in a comparatively short time.

From these observations it is concluded that the resistance of Dunaliella salina to severe osmotic shocks (which in our experimental conditions were probably more sudded than in the natural environment of the cells) is not due to a mechanism isolating the cells from the external medium or maïntaining homeostatic conditions but rather to a ready permeability of the plasmatic membranes to water and ions. As a consequence an equilibrium between internal and external osmotic conditions is established within the cell in a sufficiently short time allowing normal life conditions.

It has to be observed that during the short time span necessary for the restablishment of a new osmotic equilibrium and of a normal aspect of the plasmatic structures the cells show some clear symptome of suffering consisting in a loss of the motility and in an altered metabolism. Although this time is rather short, it appears clear that the hardness of Dunaliella to osmotic shocks involves a specific resistance of plasma proteins to denaturation.     

Ricerche istofisiologiche sullo spadice di arum

Riassunto

L'A. studia la struttura anatomica della clava dello spadice di Arum, indaga le intime modificazioni cellulari che avvengono durante il suo periodo di accrescimento, di maturità e di senescenza, e viene a rilevare alcuni segni della senescenza cellulare. Inoltre mette in evidenza le differenze morfologiche tra i procossi di necrobiosi in natura e in ambiente asfittico; segnala la vacuolizzazione delle masse cromatiniche come la causa principale della cariocinesi. Fa infine osservare che il parossismo termico (funzione prima di tale organo) rimane nei limiti biologici senza dirette azioni deleterie sulla struttura citologica della clava.