Differentiation of two locally sympatric Protopolystoma (Monogenea: Polystomatidae) species by temperature-dependent larval development and survival

The developmental response of egg stages to different environmental temperature regimes was studied in Protopolystoma xenopodis and Protopolystoma orientalis (Monogenea: Polystomatidae) isolates from southern Africa. Eggs failed to develop at 10 degrees C, whilst at 15 degrees C only P. xenopodis completed larval development, hatching 49--88 days post-collection. Respective hatching windows were 26--34 (P. xenopodis) and 37--49 (P. orientalis) days at 20 degrees C, and 18--26 and 27--37 days at 25 degrees C. Continuous maintenance at 30 degrees C was lethal for eggs of both species. There were no consistent interspecific differences in the response of egg stages to low and high temperature shocks during early embryonic development.     

Crystal structure of alkaline phosphatase from human placenta at 1.8 A resolution. Implication for a substrate specificity

Human placental alkaline phosphatase (PLAP) is one of three tissue-specific human APs extensively studied because of its ectopic expression in tumors. The crystal structure, determined at 1.8-A resolution, reveals that during evolution, only the overall features of the enzyme have been conserved with respect to Escherichia coli. The surface is deeply mutated with 8% residues in common, and in the active site, only residues strictly necessary to perform the catalysis have been preserved. Additional structural elements aid an understanding of the allosteric property that is specific for the mammalian enzyme (Hoylaerts, M. F., Manes, T., and Millán, J. L. (1997) J. Biol. Chem. 272, 22781-22787). Allostery is probably favored by the quality of the dimer interface, by a long N-terminal alpha-helix from one monomer that embraces the other one, and similarly by the exchange of a residue from one monomer in the active site of the other. In the neighborhood of the catalytic serine, the orientation of Glu-429, a residue unique to PLAP, and the presence of a hydrophobic pocket close to the phosphate product, account for the specific uncompetitive inhibition of PLAP by l-amino acids, consistent with the acquisition of substrate specificity. The location of the active site at the bottom of a large valley flanked by an interfacial crown-shaped domain and a domain containing an extra metal ion on the other side suggest that the substrate of PLAP could be a specific phosphorylated protein.     

Regulation of von Willebrand factor binding to the platelet glycoprotein Ib-IX by a membrane skeleton-dependent inside-out signal

The platelet receptor for von Willebrand factor (vWF), glycoprotein Ib-IX (GPIb-IX), mediates initial platelet adhesion and activation. We show here that the receptor function of GPIb-IX is regulated intracellularly via its link to the filamin-associated membrane skeleton. Deletion of the filamin binding site in GPIb(alpha) markedly enhances ristocetin- (or botrocetin)-induced vWF binding and allows GPIb-IX-expressing cells to adhere to immobilized vWF under both static and flow conditions. Cytochalasin D (CD) that depolymerizes actin also enhances vWF binding to wild type GPIb-IX. Thus, vWF binding to GPIb-IX is negatively regulated by the filamin-associated membrane skeleton. In contrast to native vWF, binding of the isolated recombinant vWF A1 domain to wild type and filamin binding-deficient mutants of GPIb-IX is comparable, suggesting that the membrane skeleton-associated GPIb-IX is in a state that prevents access to the A1 domain in macromolecular vWF. In platelets, there is a balance of membrane skeleton-associated and free forms of GPIb-IX. Treatment of platelets with CD increases the free form and enhances vWF binding. CD also reverses the inhibitory effects of prostaglandin E1 on vWF binding to GPIb-IX. Thus, GPIb-IX-dependent platelet adhesion is doubly controlled by vWF conformation and a membrane skeleton-dependent inside-out signal.     

Modulation of CD8+ T cell response to antigen by the levels of self MHC class I

The response of H-Y-specific TCR-transgenic CD8(+) T cells to Ag is characterized by poor proliferation, cytolytic activity, and IFN-gamma secretion. IFN-gamma secretion, but not cytotoxic function, can be rescued by the B7.1 molecule, suggesting that costimulation can selectively enhance some, but not all, effector CD8(+) T cell responses. Although the H-Y epitope binds H-2D(b) relatively less well than some other epitopes, it can induce potent CTL responses in nontransgenic mice, suggesting that the observed poor responsiveness of transgenic CD8(+) T cells cannot be ascribed to the epitope itself. Previously reported reactivity of this TCR to H-2A(b) is also not the cause of the poor responsiveness of the H-Y-specific CD8(+) T cells, as H-Y-specific CD8(+) T cells obtained from genetic backgrounds lacking H-2A(b) also responded poorly. Rather, reducing the levels of H-2(b) class I molecules by breeding the mice to (C57BL/6 x B10.D2)F(1) or TAP1(+/-) backgrounds partially restored cytotoxic activity and enhanced proliferative responses. These findings demonstrate that the self MHC class I gene dosage may regulate the extent of CD8(+) T cell responsiveness to Ag.     

Platelet serotonin concentration in dialysis patients with somatic symptoms of depression

Platelet serotonin (5-HT) concentration was measured in 65 male and 45 female chronic renal patients on hemodialysis (HD) with different somatic symptoms of depression (crying spells, irritability, sleep disturbance, fatigability, loss of appetite, weight loss, somatic preoccupation and loss of libido), to find out the relationship between the severity of symptoms and platelet 5-HT concentration. Male and female patients had significantly lower platelet 5-HT concentration than 62 male and 38 female healthy subjects. Gender-differences in platelet 5-HT values observed in healthy subjects were not found in patients. Platelet 5-HT concentration differed in the groups of patients with the different scores of particular somatic symptoms (loss of appetite and loss of libido), but was similar in patients with other somatic symptoms. There was no relationship between platelet 5-HT concentration and the severity of somatic symptoms, or between platelet 5-HT concentration and age of the patients. Gender-related differences in the occurrence of somatic symptoms were detected in patients with the different degrees of weight loss, somatic preoccupation and loss of libido. Our results suggest that platelet 5-HT concentration could not be used as a biological marker for the severity of somatic symptoms in chronic renal patients on HD.     

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.