Contributo alla conoscenza dell'ecologia delle biocenosi sulle cascade travertinose nella regione Carstica Jugoslava

Riassunto Il nostro lavoro di molti anni sulle cascade travertinose dei fiumi carstici jugoslavi era diretto verso le esplorazioni delle condizioni di vita su questi specifici biotopi. A causa di questa specificità loro erano potuti popolati solo da determinati specie di piante e di animali, i queli sono adattati su queste condizioni speciali. Esse creano le associazioni, ai queli fa la base la vigorosa vegetazione di muschi e di alghe, e un po'di meno anche di altri piante. Questa vegetazione e accompagnata da numerosi rappresentanti dai diversi gruppi di animali, come queli di Turbellaria, Gastropoda, Oligochaeta, Hirudinea, Amphipoda, Insecta ed a.Dai fattori ecologici erano esplorati le condizioni di vita fisicochimiche e biologiche. In estate la temperatura dell'aqua era sempre oltre la temperatura-limite di deposizione (oltre 14° C), e durante l'inverno generalmente erano le condizioni inconvenienti per i processi di deposizione.Nella parte superficiale delle cascade abiamo constatato due specie di abitazione in relazione della luce. Forte illuminate cascade erano popolate dalle associazioni della luce, ed a causa di meno calcificata vegetazione erano molto più. ricche di animali. Meno illuminate cascade avevano più favorevoli condizioni per il sviluppo della vegetazione travertinosa, la quale era molto calcificata, the cosa non porgeva favorevoli condizioni per il sviluppo del mondo animale.Abiamo constatato the la più favorevole velocità dell'aqua per lo sviluppo dei organismi, i quali popolano i posti delle cascade travertinose, è tra 0,5 e l,5 m/sec., sebbene sui singoli abitazioni la velocita dell'aqua era fra 0,5–3,5 m/sec.A causa di una favorevole alcalità, la quale nelle aque esplorate ammonta tra 2,8 e 5,2, i processi di deposizione sono molto attivi. E costattato un graduale abassamento dell'alcalità in direzione scendente del flume, the cosa si mette in relazione colla perdita del carbonato durante il processo di deposizione.La quantità del ossigeno ammontava da 3,5–9 ccm/l. e perciò generalmente tutte queste aque si possono considerare come poliossitipiche.Per le biocenosi delle cascade travertinose e caratteristica una grande dinamica nel Toro sviluppo. Le più primitive forme delle associazioni sono composte principalmente dai idrofiti. Con un avanzato sviluppo delle formazioni travertinose appariscono nuove stazioni con nuove associazioni. Il climax presenta la vegetazione fanerogama, la quala crew stazioni ombreggiate, dove si sviluppa speciale vegetazione travertinosa dell' ombra. Questi cambiamenti di vegetazione vengono accompagnati da numerose specie di animali dei gruppi Amphipoda, Ephemerida, Trichoptera, Plecoptera, Coleoptera ed a.In fine sono dimostrate le principali caratteristiche di vita in relazione colle condizioni fisico-chimiche e biologiche.

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Summary For a number of years, our work on travertine cascades of Yugoslav Karstic rivers has been directed towards the study of living conditions in these specific biotypes. Owing to their specificity, they could have been inhabited only by certain plant and animal species which have been adapted to these specific conditions. Their communities have been created on a rich moss and seaweed vegetation basis and, to a somewhat smaller extent, also on that of other plants. This vegetation is accompanied by numerous representatives of various animal groups such as: turbellaria, gastropods, oligochaeta, hirudinoids, amphipods, insects et al.As far as ecologic factors are concerned, physical, chemical and biological living conditions have been studied. In summer, water temperature is always above the deposition boundary (above 14°C), while in winter, conditions are generally unfavourable for deposition processes.In connection with light, two habitats were observed on the surface parts of the cascades. The strongly lighted cascades were inhabited by light communities which were considerably richer in animal population, owing to poorly calcified vegetation. As to the development of travertine vegetation, poorly lighted cascades which had been amply calcified, were in a much more favourable position and thus provided unfavourable conditions for the development of animal life.The water speed most favourable for the development of organisms inhabiting travertine cascades has been found to lie between 0.5 and 1.5 meters per second, although in individual habitats water speed amounted to between 0.5 and 3.5 meters per second.Owing to favourable alkalinity, amounting, in the waters investigated, to between 2.8 and 5.2, depositing processes have been very intense. The gradual lowering of alkalinity in the downstream course of rivers, which is brought into connection with the losing of carbonates during the deposition process, has also been established.As the quantity of oxygen amounted to between 3.5–9 ccm/l, these waters can be considered to be polyoxitypical.The biocenosis on travertine cascades are characterized by their very dynamic development. The most primitive forms of communities are mainly composed of hydrophytes. The further development of travertine forms brings about new habitats with new communities. The climax is represented by phanerogamic vegetation, creating rocky habitats where special travertine shade vegetation develops. These changes in vegetation have been accompanied by numerous animal species of the afore-mentioned groups.Finaly, the main characteristics of life in terms of physical, chemical and biological conditions have been presented.

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Zusammenfassung Die mehrjärige Arbeit der Autoren auf den Kalktuffbildenden Wasserfällen der jugoslawischen Karstgewässer war den Erforschungen der Lebensbedingungen auf diesen spezifischen Biotopen gewidmet. Wegen ihrer Eigentümlichkeit konnten die Kalktuffwasserfälle nur von bestimmten Pflanzen- und Tierarten besiedelt werden, die an these besonderen Bedingungen angepasst sind. Sie bilden Gemeinschaften auf eine üppige Moos- und Algenvegetation und etwas weniger auch auf anderen Pflanzen. Diese Vegetation wird von zahlreichen Vertretern verschiedener Tiergruppen begleitet, wie Turbellaria, Gastropoda, Oligochaeta, Hirudinea, Amphipoda, Insecta u.a.Von ökologischen Faktoren wurden die physikalisch-chemischen und biologischen Bedingungen untersucht. Im Sommer war die Wassertemperatuur immer über der Grenztemperatur der Ablagerung (über 14°C), während die Ablagerungsbedingungen im Winter im allgemeinen ungünstig waren.In den oberflächenlichen Teilen der Wässer\:falle wurden, im Verhältnis zu dem Licht, zwei Arten von Standorten festgestellt. Die stark belichteten Wasserfälle sind von Lichtgerneinschaften besiedelt, die wegen der weniger kalzifizierten Vegetation viel mehr Tiere enthalten. Weniger belichtete Wasserfälle zeigen günstigere Bedingungen für eine Entwicklung der Kalktuffvegetation. Diese Vegetation wird sehr kalzifiziert und ist für der Entwicklung der Tierwelt ungünstig.Es wurde festgestellt, dass die günstige Wassergeschwindigkeit für die Entwicklung von Organismen, die die Standorte der Kalktuffwasserfälle besiedeln, zwischen 0,5 and 1,5 m-Sek ist, wiewohl die Wassergeschwindigkeit an einzelnen Standorten zwischen 0,5 and 3,5 m-Sek betrug.Wegen der günstigen Alkalität (2,8–5,2) sind die Ablagerungsvorgänge sehr aktiv. Flussabwärts wurde ein allmählicher Fall der Alkalitätwerte festgestellt, was auf den Verlust des Karbonates während der Ablagerungsvorgänge zurückgeführt wird.Die Sauerstoffmenge beträgt zwischen 3,5–9 ccm/l; im allgemeinen können wir deshalb all these Gewässer als polyoxytypisch betrachten.Für die Gemeinschaften der Kalktuffwasserfälle ist eine grosse Dynamik in ihrer Entwicklung charakteristisch. Die primitivsten Formen der Lebensgemeinschaften sind hauptsächlich aus Hydrophyten zusammengesetzt. Mit der weiteren Entwicklung der Kalktufformen erscheinen neue Standorte mit neuen Gemeinschaften. Das Klimax stellt die Vegetation der höheren Pflanzen tar, die Schattenstandorte macht, wo sich eine besondere Schattenkalktuf-vegetation entwickelt. Diese Vegetationsänderungen werden von zahlreichen Tierarten der genanten Gruppen begleitet.Zum Schluss wird die Hauptcharakteristik des Lebens in Bezug auf die physikalisch-chemischen und biologischen Bedingungen dargestellt.

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Botaniki institut Univerziteta Zagreb

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Bioloki institut Univerziteta Zagreb     

Effect of isoflavone genistein on insulin receptors in perfused liver of ovariectomized rats

The experiments were carried out on ovariectomized Wistar rats. Their livers were perfused with basic perfusion medium (BPM) or BPM supplemented with isoflavone genistein, insulin or combination of the two factors. The obtained results support the hypothesis that genistein influences the kinetics of insulin binding to cell membranes changing the number of insulin receptors and dissociation constant (Kd). BPM supplementation with genistein decreased number of high affinity insulin receptors (HAIR) both in livers treated and untreated with insulin. The amount of HAIR diminished significantly from 610 +/- 77 x 10(-15) (no genistein) to 238 +/- 72 x 10(-15) mol/mg of membrane protein (supplement of genistein). Similarly, genistein reduced slightly the amount of HAIR even when added together with insulin (372 +/- 59 x 10(-15) mol/mg) in comparison to rats perfused with medium containing insulin but not the isoflavone (421 +/- 46 x 10(-15) mol/mg). Simultaneously, genistein decreased significantly Kd for HAIR (perfusion with BPM--1.44 +/- 0.18 x 10(-9) mol/l; perfusion with BMP + genistein--0.83 +/- 0.20 x 10(-9) mol/l). Such effects of genistein during liver perfision did not take place when the liver membranes were in vitro incubated with this xenobiotic.     

Roundness of epithelial nuclei in bronchial mucosa

OBJECTIVE: To estimate the shape of epithelial nuclei in bronchial mucosa. STUDY DESIGN: Bronchoscopic mucosal samples from 12 patients with chronic bronchitis and 14 patients with squamous cell bronchial carcinoma were routinely processed and stained with the hematoxylin and eosin method. Fields with stratification and squamous metaplasia were selected. The roundness of epithelial nuclei was estimated using Lucia, version 3.51 ab, with an objective of 40:1 (NA = 0.65) and final magnification of 1,900:1. The images were manually edited. Roundness was calculated from area and perimeter. RESULTS: The mean roundness in stratification and squamous metaplasia in bronchial mucosa from carcinoma patients (0.90 +/- 0.04) was significantly greater than in bronchial mucosa from chronic bronchitis patients (0.80 +/- 0.006) (P < .05). CONCLUSION: Our results indicate that cell nuclei in stratification and squamous metaplasia in patients without bronchial cancer are more elongated than nuclei found under the same conditions in patients with squamous cell carcinoma.     

Digital image analysis of silver-stained nucleolar organizer region--associated proteins in endometrial cytologic samples

OBJECTIVE: Digital image analysis was applied to determine the number, area and size of silver-stained nucleolar organizer regions (AgNORs) in cytologic samples from curettage in normal, hyperplastic and malignant endometrium. STUDY DESIGN: Thirty-two archival cytologic smears from curettage (previously stained by the Papanicolaou method) with the histologic diagnosis (4 inactive endometrium, 5 secretion, 5 proliferation, 5 simple hyperplasia, 5 complex hyperplasia, 3 atypical hyperplasia, 5 adenocarcinoma, grade 1) were analyzed with the AgNOR technique. Count, area and size of AgNORs were analyzed in 50 cells per sample using a magnification of 1,000x. Quantitative analysis was performed on an SFORM digital imaging system. Data were analyzed with the SPSS/PC+ program. Mann-Whitney and chi 2 tests were performed. RESULTS: The average value of AgNOR count increased from normal to hyperplastic endometrium and well-differentiated adenocarcinoma. Differences were significant except between atypical hyperplasia and adenocarcinoma. Four, five and more AgNORs in 40% or more of the nuclei were found in complex and atypical hyperplasia and adenocarcinoma. Proliferation, and simple and atypical hyperplasia had similar mean values of AgNOR area. The mean total AgNOR area value increased from normal to hyperplastic had similar mean values of AgNOR area. The mean total AgNOR area value increased from normal to hyperplastic and well-differentiated adenocarcinoma. Differences were statistically significant. AgNOR size in well-differentiated adenocarcinoma was significantly different from that in normal endometrium and different grades of hyperplasia. CONCLUSION: Digital image analysis of AgNOR count, area and size enabled a distinction to be made between normal, hyperplastic and malignant endometrium.     

Development of cytotrophoblast columns from explanted first-trimester human placental villi: role of fibronectin and integrin alpha5beta1

Human first-trimester floating mesenchymal villi explanted onto gels of collagen I or Matrigel were observed to undergo de novo development of anchoring sites. These consisted of cytotrophoblast columns that formed by proliferation of stem villous cytotrophoblast cells, as revealed by whole-mount and thin-section microscopy and incorporation of bromodeoxyuridine into DNA. Column formation occurred exclusively at the distal tips of the villi. No column formation was observed in tissue explanted onto agarose. On Matrigel, the developing columns penetrated downwards into the matrix, whereas on collagen I, cytotrophoblast sheets spread across the surface of the gel and merged to form a shell. The developing columnar cytotrophoblast up-regulated integrins alpha1beta1 and alpha5beta1 and produced an extracellular matrix containing oncofetal fibronectin, as in vivo. Function-blocking antibodies were used to investigate the role of the integrin-fibronectin interaction in anchoring villus development on collagen I. Antibodies to fibronectin and the integrin subunits alpha5 and beta1, added at 24 h, all changed the pattern of cytotrophoblast outgrowth. Anti-fibronectin caused cell rounding within the cytotrophoblast sheet and increased the population of single cells at its periphery. Anti-integrin alpha5 caused rounding and redistribution of cells within the outgrowth. In the presence of anti-integrin beta1, cell-collagen interactions within the sheet were destabilized, often leading to the appearance of an annulus of aggregated cells at the periphery. These results show that 1) mesenchymal villi retain the potential to form anchoring sites until at least the end of the first trimester, 2) adhesion to a permissive extracellular matrix stimulates cytotrophoblast proliferation and differentiation along the extravillous lineage, 3) integrin alpha5beta1-fibronectin interactions contribute significantly to anchorage of the placenta to uterine extracellular matrix. We suggest that as the developing placenta ramifies, new sites of anchorage form whenever peripheral villi contact decidua. This process is predicted to contribute to the stability of the placental-decidual interface.     

An EPR study of the transfer and trapping of holes produced by radiation in guanine(thioguanine) hydrochloride single crystals

Single crystals of guanine hydrochloride monohydrate, guanine hydrochloride dihydrate and anhydrous guanine dihydrochloride, doped with thioguanine, were irradiated with X and gamma rays. In all three systems the dominant radicals were associated with thioguanine. In the former two systems the stabilized species is the thiyl radical, formed by initial loss of an electron at some of the guanines in the crystal lattice, followed by hole migration to thioguanine and subsequent deprotonation of the radical formed. In the anhydrous guanine(thioguanine) dihydrochloride, that process is followed by acquisition of a chlorine ion. In the guanine hydrochloride monohydrate and guanine hydrochloride dihydrate lattices, systems of interacting closely spaced stacked bases and strings of chloride ions might support the migration of electrons and/or holes. In anhydrous guanine dihydrochloride, neither the bases nor the Cl- ions alone are capable of providing the means for the long-range electron, energy and spin transfer. It is the interchangeable sequence of the charged bases and the Cl- ions that makes the supporting strings or networks. The ultimate chlorination of the thioguanine-centered electron-loss radicals depends mainly on the availability of the Cl- ions and the space for their accommodation in the vicinity of the sulfur atom.     

Inhibition of p56(lck) tyrosine kinase by isothiazolones

Lck encodes a 56-kDa protein-tyrosine kinase, predominantly expressed in T lymphocytes, crucial for initiating T cell antigen receptor (TCR) signal transduction pathways, culminating in T cell cytokine gene expression and effector functions. As a consequence of a high-throughput screen for selective, novel inhibitors of p56(lck), an isothiazolone compound was identified, methyl-3-(N-isothiazolone)-2-thiophenecarboxylate(A-125800), which inhibits p56(lck) kinase activity with IC50 = 1-7 microM. Under similar assay conditions, the isothiazolone compound was equipotent in blocking the ZAP-70 tyrosine kinase activity but was 50 to 100 times less potent against the catalytic activities of p38 MAP kinase and c-Jun N-terminal kinase 2alpha. A-125800 blocked activation-dependent TCR tyrosine phosphorylation and intracellular calcium mobilization in Jurkat T cells (IC50 = 35 microM) and blocked T cell proliferation in response to alloantigen (IC50 = 14 microM) and CD3/CD28-induced IL-2 secretion (IC50 = 2.2 microM) in primary T cell cultures. Inhibition of p56(lck )by A-125800 was dose- and time-dependent and was irreversible. A substitution of methylene for the sulfur atom in the isothiazolone ring of the compound completely abrogated the ability to inhibit p56(lck) kinase activity and TCR-dependent signal transduction. Incubation with thiols such as beta-ME or DTT also blocked the ability of the isothiazolone to inhibit p56(lck) kinase activity. LC/MS analysis established the covalent modification of p56(lck) at cysteine residues 378, 465, and 476. Together these data support an inhibitory mechanism, whereby cysteine -SH groups within the p56(lck) catalytic domain react with the isothiazolone ring, leading to ring opening and disulfide bond formation with the p56(lck) enzyme. Loss of p56(lck) activity due to -SH oxidation has been suggested to play a role in the pathology of AIDS. Consequently, a similar mechanism of sulfhydryl oxidation leading to p56(lck) inhibition, described in this report, may occur in the intact T cell and may underlie certain T cell pathologies.     

AFM imaging of surface adsorbed polymeric 3-alkylpyridinium salts from the marine sponge Reniera sarai

Bioactive 3-alkylpyridinium polymers (poly-APS) have recently been isolated from the marine sponge Reniera sarai. Previous results have shown that these molecules in aqueous solutions form supramolecular aggregates with an average hydrodynamic radius of 23±2 nm. To obtain additional evidences about the shape and the dimensions of poly-APS aggregates, we used atomic force microscopy (AFM) operating in tapping mode. The images clearly showed adsorbed aggregates with a lateral dimension of ≈40 nm and a thickness of the order of ≈1 nm. The distribution of volumes of the adsorbed aggregates is very similar to the distribution of hydrodynamic radii as obtained from the dynamic light scattering experiments. The volume distribution of these aggregates shows a maximum at 1750 nm³, which corresponds to a sphere with a radius of 7.5 nm.     

Molecular properties of 4-substituted indole-3-acetic acids affecting pea pericarp elongation

Pea (Pisum sativum L.) fruit naturally contain the auxins, indole-3-acetic acid (IAA) and 4-chloroindole-3-acetic acid (4-Cl-IAA). However, only 4-Cl-IAA can substitute for the seeds in maintaining pea fruit growth in planta. The importance of the substituent at the 4-position of the indole ring was tested by comparing the molecular properties of 4-X-IAA (X = H, Me, Et, F, or Cl) and their effect on the elongation of pea pericarps in planta. Structure-activity is discussed in terms of structural data derived from X-ray analysis, computed conformations in solution, semiempirical shape and bulk parameters, and experimentally determined lipophilicities and NH-acidities. The size of the 4-substituent, and its lipophilicity are associated with growth promoting activity of pea pericarp, while there was no obvious relationship with electromeric effects.     

Temperature dependence of delayed fluorescence induction curve transients

The temperature dependence of delayed millisecond fluorescence (DF) induction curve transients was investigated. The transients were obtained by keeping intact maize leaf segments in the dark for 30 to 300 s before illumination. The temperature dependence of DF induction revealed abrupt changes in activation energy of the recombination process. Those changes highly overcome the lowest energy barriers for certain types of chemical reactions, implying significant possible alterations in the DF mechanism itself. On the other hand, the particular transients responses expressed some specificities. Both the electrochemical gradient controlled changes, and the temperature induced changes contribute to it.