Ricerche istologiche sull' innervazione del timo dei Sauropsidi

Zusammenfassung Die sehr zahlreichen Nervenfasern für die Thymus der Sauropsiden gehen hauptsächlich vom zervikalen sympathischen Strang, aber zum Teil auch vom Vagus und vielleicht von den ventralen Ästen der zervikalen Nerven aus und erreichen die Thymus, indem sie den Gefäßen entlang laufen.Die Faserbündelchen, in welchen man oft isolierte oder in Gruppen gesammelte sympathische Zellen antrifft, dringen in das Thymusparenchym ein und hier verästeln sie sich sehr stark. Ein kleiner Teil der Nervenfasern sind Vasomotoren, ein anderer ebenfalls kleiner Teil verschwindet innerhalb von Gruppen von epithelioiden Zellen, welche oft mit drüsenähnlichen Höhlungen versehen sind (einige von diesen epithelioiden Anhäufungen erinnern im Aussehen an dieHassall-Körperchen der Säugetiere); echte typische H. K. sind sehr selten in erwachsenen Tieren nachweisbar.Der größte Teil der Nervenfasern erreicht jedoch die myoiden Zellen und verbindet sich mit denselben. Bei Cheloniern und bei Hühnern ist der Nervenanteil, der den myoiden Elementen vorbehalten ist, wirklich übermäßig groß.Die myoiden Zellen sind bekanntlich ein oft sehr ansehnlicher Bestandteil der Thymus der Sauropsiden, wie bei anderen Wirbeltiergruppen. Sie sind regressiven und progressiven Veränderungen unterworfen: je nach den Jahreszeiten (Dustin), ebenso besonderen funktionellen Bedingungen wie Fasten, Winterschlaf (Hammar); sie zeigen beim Huhn eine Hyperplasie-Hypertrophie als Folge der Kastration und des Alters (Terni).In vorliegenden Untersuchungen sind nebenbei einige neue Tatsachen über die Morphologie der myoiden Zellen festgestellt worden, unter anderen folgende: a) ihre histologische Differenzierung während der Entwicklung tritt sehr spät ein; b) sie sind räumlich von dem retikulär-kollagenen Netze des Thymusläppchens unabhängig, und sie besitzen keine retikulosarkolemmale Membran; c) die strahlenförmige (konzentrische) oder regellose Anordnung der Querstreifung der Myofibrillen in den großen myoiden Elementen bildet sich als Resultat der Verschmelzung von vorher unabhängigen Zellen (weshalb die besprochenen Elemente echte Syncytien sind); d) im Protoplasma der myoiden Zellen finden sich Spuren von Glykogen; usw.Die Verbindungen zwischen Nervenfasern und myoiden Elementen und andere Einzelheiten der feineren Verteilung der Nervenelemente im Thymusläppchen wurden bei Cheloniern und Vögeln besonders eingehend untersucht. An der Oberfläche der myoiden Zellen bilden die Nervenfasern Windungen oder spatel-, knopf-, keulchen- oder füßchenförmige Verbreitungen, welche der myoiden Substanz anhängen (neuromyoide Verbindungen).Die Nervenfasern, welche sich durch diese Endigungsweise mit den myoiden Zellen verbinden, gehören sehr wahrscheinlich zu den postganglionären Neuronen, welche entweder im Thymus (intraparenchymale oder perivasale mikroskopische Ganglien) oder im zervikalen sympathischen Gefäßgeflecht oder im sympathischen Grenzstrang liegen.Über Wesen, Zweck und Ziel der Vagusfibern habe ich mir kein bestimmtes Urteil bilden können.Außerdem befinden sich im Thymusläppchen wenige Nervenzellen des gewöhnlichen sympathischen Typus und in größerer Zahl kleine isolierte Nervenzellen, die zweifellos mit den interstiziellen ZellenCajals zu identifizieren sind. Diese interstiziellen Neuronen befinden sich meistensin der Nähe der myoiden Zellen und liegen oft auf der Oberfläche derselben, indem sie sie mit ihren verästelten Fortsätzen umfassen. Manchmal verbindet sich ein langer und feiner Fortsatz der interstiziellen Neuronen mit einer entfernt gelegenen myoiden Zelle. Diese Nervenzellen müssen zum größten Teil alsautonome effektorische Neurone aufgefaßt werden, wegen ihrer innigen Verbindung mit der kontraktilen Substanz. Wenn eine Kontraktionsmöglichkeit der myoiden Zellen auch nicht in Abrede zu stellen ist, ist es nicht recht verständlich, was für eine nützliche Wirkung ihre Kontraktion haben könnte (darum gebrauchen wir den Ausdruck effektorisch und nicht motorisch).Man kann oft beobachten, daß an der Oberfläche einer und derselben myoiden Zelle sich sowohl Fäden von exogenen Nervenfasern, als auch verästelte Fortsätze einer kleinen interstiziellen paramyoiden Zelle ausbreiten.Obwohl in der Thymus (wie auch im Darm;Cajal) das Wesen der Fortsätze der interstiziellen Neuronen zweifelhaft ist, mangels sicherer differentialer Merkmale zwischen Neuriten und Dendriten, ist doch das Aussehen der mit den myoiden Zellen verbundenen Fasern ganz verschieden von demjenigen der Fortsätze der interstiziellen Zellen.In einigen wenigen Fällen ist es möglich, einen dünnen und langen Fortsatz (Neurit?) der interstiziellen Zelle zu verfolgen, welcher ein kleines Blutgefäß erreicht; es ist möglich, daß er längs desselben eine proximale Richtung verfolgt. Dieses Verhalten läßt die Vermutung zu, daß wenigstens einigen dieser Neuronen die Bedeutung vonrezeptorischen Neuronen zuzuschreiben sei.Die Deutung des reichen Zuflusses und der ansehnlichen Verteilung des nervösen Anteils im Thymusparenchym der Sauropsiden ist, vom Gesichtspunkt ihrer möglicherweise endokrinen Funktion, nicht leicht: Sei es, weil die Innervation anderer endokriner Drüsen histologisch nicht genau bekannt ist (mit Ausnahme der Paraganglien); sei es, weil es überhaupt zweifelhaft ist, ob die Thymus eine innere Sekretion besitzt.Es ist möglich, daß die Anwesenheit der neuromyoiden Synapsen in der Thymus (welche hier zum ersten Male hervorgehoben wird), wenn auch die myoiden Zellen nicht kontraktionsfähig sein sollten, trotzdem mit dem Kohlenhydratenstoffwechsel in Zusammenhang steht, ähnlich wie es für die neuromuskularen Synapsen des zerebrospinalen Systems angenommen wird (Roncato).Der beinahe übergroße Reichtum nervöser Verzweigungen und neuromyoider Verbindungen, besonders bei Cheloniern, legt die Vermutung nahe, daß in zyklischen degenerativen Vorgängen des Thymusparenchyms eine Zerstörung und nachfolgende übermäßige Regeneration von Nervenfasern stattfindet; andererseits läßt die Zunahme der Zahl und Verzweigung der Nervenfasern im Kapaun und alten Hahn (Terni) die begründete Vermutung zu, daß es sympathische Neuronen gibt, welche einer auch verspäteten progressiven histologischen Differenzierung ihrer Neuriten fähig sind (eine verspätete histologische Vervollkommnung des Zellenleibes und der Dendriten in sympathischen Neuronen ist schon in menschlichen Ganglien bekannt;Terni).Aus diesen Gründen lassen die voliegenden Beobachtungen über die Thymus der Sauropsiden den Gedanken aufkommen, daß die stark entwickelte autonome Innervation der Thymus in der Funktion dieses Organs eine bedeutende Rolle spielt: sei es als Sitz besonderer Reize, welche sich wahrscheinlich in den neuromyoiden Apparaten entladen, sei es, weil die Nervenfasern mit Vorrichtungen versehen sind, welche auf lokale oder allgemeine Reize mit besonderer Empfindlichkeit morphologisch reagieren.     

Ricerche Sulla Vegetazione dei Dintorni di Firenze

Summary

It is related on some phytocenoses of the southerly Florence hills, lying on the boundary of the two basal biochores of peninsular vegetation. Although the proximity and the chorographical analogy at the south-westerly ones and at Ceceri Mount, which are included yet in the » Quercetum Ilicis « ambit, these hills are whereas sensible displaced in the » Quercetum pubescentis «. They have microtherme elements of higher planes, but they have in yet the marks of littoral biochore, for instance Smilax aspera, abundantly penetrating in hedges and in a pine-grove but non in coppices of Quercus Cerris.     

Ricerche Sulla Vegetazione dei Dintorni di Firenze

Riassunto

L'A. espone in questo lavoro i risultati di ricerche sistematiche e fitogeografiche sulla vegetazione di Monte Ferrato (presso Prato in Toscana), piccolo gruppo di colline costituite da rocce ofiolitiche (serpentino, eufotide ecc.), Dopo averne elencata la florula, dove riporta anche le diagnosi di alcune forme nuove, l'A. prende in esame la vegetazione dei principali tipi di stazione, che vi ha potuto riconoscere, in base a criteri fisionomici e statistici. Considera poi le caratteristiche morfologiche delle specie pi[ugrave] significative del serpentino, che raggruppa in cinque tipi di speciali morfosi. Sulla base dell'analisi della distribuzione geografica di alcune notevoli entità che si presentano a M. Ferrato in stazione disgiunta rispetto al loro areale, dello studio geografico e sistematico degli endemismi, e in genere poi di tutte le specie pi[ugrave] significative di questa Flora, l'A. ne discute il valore fitogeografico e climatico, rilevando e discutendo la convivenza di specie di diverso valore fitogeografico, in rapporta alle particolari condizioni microstazionali.     

Ricerche Sulla Flora e Vegetazione dei Fontanili Dell'Agro Milanese

Abstract

Nucleic Acids in Ripening of Castor Bean Endosperm. - I. Quantitative and Qualitative Changes of total RNA. — The ripe Castor Bean seed endosperm (Ricinus Communis var. Sanguinea) has a very low level of nucleic acids and particularly of ribosomal RNA. However, they rapidly increase during the germination of the seed (S. Cocucci et al., Acc. Naz. Lincei, 38, 545, 1965).

The behaviour of the nucleic acids, obtained by phenol extraction from Castor Bean seed endosperm at different ripening stages, is the following:

1. From the moment when the developing seed has reached the maximal fresh weight to the moment of its complete ripening, the RNA content decreases from about 700 μg per seed to about 200 μg.

2. During the same period the DNA level (about 13–15 μg per seed) remains nearly costant.

3. Fractionation by sucrose density gradient of the phenol extracted RNA (H. L. Sanger and C. A. Knight, Biochem. Biophys. Reserch Commun., 13, 445, 1963) shows that during the ripening of the seed the high molecular weight RNA decreases much more than the low molecular weight RNA.

4. Radioactive phosphate injected in the seeds is incorporated in the RNA at all the stages. Fractionation by sucrose density giadient shows that the phosphate is essentially incorporated in low molecular weight RNA and there is pratically no labelling of the heavier RNA after quite a long period (2 hr.).

These data suggest that the decrease of the RNA during the ripening of the seed can be due to a fall in the ability to synthesize high molecular RNA.     

Ricerche morfologiche ed istochimiche sui lipidi nel pancreas dei mammiferi

Con 10 figure nel testo.     

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 Sugli Stami dei Fiori Sani e Parassitati del Melandrium Album (Miller) Garcke

Abstract

Researchs on the stamens of the healty and parasited flovers of Melandrium album. — The author has examined the structure of the stamens filaments in the healthy and parasited flowers of Melandrium album. The structural modifications induced by the mycelial hyphae of Ustilago violacea expecially in such filaments are pointed out.     

Influenza dell' aria rarefatta sull' ontogenesi

A.Aggazzotti, Nota I. La perspirazione delle ova di gallina durante lo sviluppo in alta montagna. Arch. f. Entw.-Mech. Bd. 36. 1913. S. 633 e Atti dei Laboratorii »A. Mosso« sul Monte Rosa. Vol. 4.     

Ricerche Embriologiche Sulle Martyniaceae

Riassunto

L'A. ha studiato lo sviluppo del gametofito e dell'albume in Proboscidea Jussieui Steud. e in P. lutea Stapf: il gametofito risulta di tipo normale e Palbume di tipo cellulare fino all'inizio. Particolare attenzione è stata posta nel descrivere le caraterristiche morfologiche di due tessuti di nutrizione dell'ovulo: una modesta epistasi ed una ipostasi di proporzione notevole, fornita anche di un cambiforme. E stata pure messa in rilievo l'importanza dell'epidermide. Interna del tegumento per il mantenimento allo stato embrionale dei tessuti circostanti. Il numero dei cromosomi è 2n=30 in ambedue le specie.     

Ricerche Sull'ultrastruttura della Parete Cellulare

Abstract

A study about the cell wall of AVENA coleoptile epidermis cells. — A new type of lamellae structures embedded in the outer periclinal wall of oat coleoptile epidermis cells has been observed. These structures are present more frequently in the inner non-cutinized portion of the cell wall; their orientation, most often parallel to the cell surface, follows a regular pattern. They are formed by alternate layers of electrontransparent and electron-dense bands. The thickness of these lamellar bodies is about 200–300 Å; their length is rather difficult to determinate. They are bounded by a 30–40 Å thick membrane; the inner compartment is formed by a central highly manganophilic zone 50–70 Å thick where several thin lamellae can be seen and by two lateral zones about 40–50 Å in thickness.

Embedded in the cutinized portion of the wall some elliptical bodies have also been observed, surroundedd by a single membrane, 20 Å in thickness. The interior of these bodies shows thin lamellae enclosed in an electron-transparent stroma.

In experimental conditions unfavourable to growth, the frequency of these structures falls greatly. When the cell distension comes to end, their aspect undergoes deep changes. It is proposed in this paper that these new structures are involved in cell wall growth and development.     

Ricerche sulla fisiologia dell'acido ascorbico

Summary

Structural viscosity of plasm in plants varies over a wide range under the influence of a number of different stimuli, as both internal and surrounding factors are bound to affect it. If viscosity is regarded as an index of the dispersion degree of plasmatic colloids, it will be easily gathered that, parallel with it, also the reactive surface of these is subject to both quantitative and qualitative variations. The result is that such stimuli as determine the aforesaid variations in the living plasm structure, ultimately should have a bearing on the intensity of all such functions as are controlled by plasm. Of all the stimuli bound to exert the effects referred to above, the Authors have devoted their special attention to auxins. Under their influence the plasm structure undergoes such modifications — which can be appraised with the plasmolysis method — that an increase in viscosity is noted, the latter phenomenon being followed — in the Authors' opinion — by an increase in the dispersion degree of the plasmatic colloids. Consequently, several functions are enhanced, the most evident of these being the cells' growth. On the other hand, in such cells where the membrane have reached such a degree of evolution as to be no longer extensible, the auxins cause the same phenomena as in the plasm, without this being, however, accompanied by a resumption of the growing process.

The Authors have expressed the opinion that plants may have a way to regulate the rate of such functions as are controlled by plasm not only by producing some substances wich, by causing a higher dispersion of the plasmatic colloids, act as stimulants, but also by producing some other substances having an opposite action; these substances, by exerting the contrary effect on the plasmatic colloids, would act as inhibiting agents. According to this assumption the auxin-type substances would be offest by some anti-auxinic substances, the actual extent of all functions, as well as the reaction to surrounding stimuli, would thus be controlled by a system of two classes of regulators having opposite effects, and by their relative amount. In the last few years several researchers have investigated the anti-auxin field; the Authors, however, specifically refer to the ascorbic acid (AA) as the mos widely diffused an the one having the most general significance.

In this paper the Authors propose to study antagonist relation between auxins and AA under the limited standpoint of the effect that the two substances exert on the plasm's structural viscosity. Their experimental results have shown that

a) the administration of AA, no matter which technique has been used, cuts the plasmolisys time (if concave in the controls, the latter become convex in the tissues treated), consequently decreasing the plasm viscosity. Such a reduction, which is noted in both the stem and roots, is, at least to a certain extent, proportional to the amount of AA actually to be found in the organs;

b) the very same result is obtained when a variation is introduced in the surrounding conditions which, by affecting the photosynthetic process, influence the amount of AA which is present in the organ. More particularly, it has been found that, after being kept for a certain number of hours in the dark, the vegetal organs — notably the leaves and green stems — contain far lower amounts of AA than those which could be found when the same organs were exposed to the light. Likewise, the plasm viscosity is far higher in the dark than in the light.

Etiolated plants, too, contain a far lesser amount of AA than the controls which have grown in the light, and their plasm is far more viscous than in the green controls. The experimental introduction of AA, anyway, lowers the plasmatic viscosity both in the etiolated specimens and in the controls.

The roots, wich are extremely poor in AA contents as compared with the green organs, also have a far more viscous plasm;

c) the antagonist relation between the action of the AA and the substances having an auxinic action is also indirectly evidenced by the AA being capable of cutting or even offsetting the action of the auxinic type substance. As a matter of fact, in such plants as have been experimentally enriched in their AA contents the plasm viscosity undergoes only a very slight variation subsequent to the administration of substances exerting an auxinic action.

It is, anyway, a well-know fact that roots, being extremely poor in AA as compared with the stem, are influenced to a far larger extent than the latter by the action of all growth-promoting substances; d) AA is not a specific antagonist of the auxins. As a matter of fact, it has been found that it opposes the action developed by indoleacetic and indolebutyric acids, as well as the action exerted by some other substances, such as xanthine, uric acid and colchicine whose auxin-like action on both plasm viscosity and cellular enlargement has already been detected.     

Ricerche Sulla Vegetazione Dell'etruria Marittima

Summary

The dates of foundation of the oldest university botanical gardens.

The dates of foundation of the oldest Botanical Gardens in Italy are not well known to the greatest part of the students of Botanical History.

Also today Ms. A. Guillaumin in his « Histoire de la Botanique en France (Paris, 1954) pag. 188» writes it was « Serenissima Repubblica Veneta » who founded the first Botanical Garden in 1533, whilst in that year only the chair of Bonafede had been constituded and the foundation of the Botanical Garden in Padoa happened later in 1545.

Really the most ancient Botanical Garden in the world is not that of Padoa, but that of Pisa.

Recently in the « Archivio di Stato » of Florence has been discovered by Fedeli a letter dated July 4 th 1545 written by Luca Ghini. From it it is clear that already a month before that date Luca Ghini was collecting plants to be coultivated in the academic garden of Pisa « for utility of students ».

The critical analysis of many papers by Luigi Anguillara allowe us to establish that Luca Ghini with the same Anguillara collected plants in the surreoundings of Pisa and on the Apuane Alps, from 1543 to 1544, and planted them in the academic garden of Pisa, which therefore must be considered the first Botanical Garden in the world, founded in the Summer 1543.

The second Botanical Garden in order of time is that of Padoa having been established by the « Senato Veneto » in 1545 and actually founded on July 7 th 1545 (de Visiani). The first director of Botanical Garden of Padoa was Luigi Anguillara after having left Pisa where he cooperated with Luca Ghini to found the Botanical Garden of Pisa.

Finally the third Botanical Garden is that of Florence (« Giardino dei Semplici ») founded as a dependance of that of Pisa by Luca Ghini, for school utility during the holyday, when the Florentine students remained at home. The date of its founding is December 1st 1545, as it appears from an an attorney document dated November 16th 1545 preserved in the « Archivio di Stato » of Florence (Volpi).

In conclusion the right chronology of the oldest University Botanical Gardens in the world is as follows:

1st: Pisa, Summer 1543

2nd: Padoa, July 7th 1545

3rd: Florence, December 1st 1545.