Fine structure of the gills of some Indian air-breathing fishes

A detailed account is given of the structure of the gills of Clarias batrachus, Heteropneustes (= Saccobranchus) fossilis, Channa punctata, Monopterus (= Amphipnous) cuchia and Boleophthalmus boddaerti, based upon light and electron microscopy. In all five species the basic organization into primary and secondary lamellae is apparent but the latter are very much more modified in Monopterus. Three main layers separate the water and blood on the surface of the secondary lamellae. The outer epithelium is usually two layered but may be multilayered close to the origin of the secondary lamellae from the gill filament. The basement membrane is relatively thin and a middle dense layer containing collagen fibrils separates two clear layers. The pillar cells, so characteristic of secondary lamellae, are present in all except Monopterus and flanges from these cells surround the blood channels with the exception of the marginal channels. The latter are lined by endothelial cells which line all the blood channels of Monopterus. The overall thickness of the three layers comprising the water/blood barrier ranges from 1.5 to 13 microns. A number of modifications to this basic organization can be related to the degree of dependence of the different species on air-breathing. Boleophthalmus is the only species commonly found in brackish water and its secondary lamellae have well developed lymphoid spaces between two layers of the epithelium. Special densely-stained regions of the pillar cell flanges were also present in this fish and may have a supporting function.     

The primary color-factors ofLychnis and color-inhibitors ofPapaver Rhoeas

Ohne Zusammenfassung

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The primary color-factors ofLychnis and color-inhibitors ofPapaver Rhoeas

     

Testing optimal foraging models for air-breathing divers

Models of diving optimality qualitatively predict diving behaviours of aquatic birds and mammals. However, none of them has been empirically tested. We examined the quantitative predictions of optimal diving models by combining cumulative oxygen uptake curves with estimates of power costs during the dives of six tufted ducks, Aythya fuligula. The effects of differing foraging costs on dive duration and rate of oxygen uptake (V_O2up) at the surface were measured during bouts of voluntary dives to a food tray. The birds were trained to surface into a respirometer after each dive, so that changes in V_O2up over time could be measured. The tray held either just food or closely packed stones on top of the food to make foraging energetically more costly. In contrast to predictions from the Houston & Carbone model, foraging time (t_f) increased after dives incorporating higher foraging energy costs but surface time (t_s) remained the same. While optimal diving models have assumed that the cumulative oxygen uptake curve is fixed, V_O2up increased when the energy cost of the dive increased. The optimal breathing model quantitatively predicted ts in both conditions and oxygen consumption during foraging (m₂t_f) in the control condition, for the mean of all ducks. This offers evidence that the ducks were diving optimally and supports the fundamentals of optimal diving theory. However, the model did not consistently predictt_s or m₂t_f for individual birds. We discuss the limits of optimal foraging models for air-breathing divers caused by individual variation. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.      

Forms of reduplication primary and secondary

Ohne Zusammenfassung

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Forms of reduplication primary and secondary

     

Fragmenta mycologica VI. Has keratinomyces ajelloi vanbreuseghem, 1952 microconidiums?

Summary It is demonstrated and the primary observation ofVanbreuseghem is again confirmed thatKeratinomyces ajelloi does not produce microconidiums.

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Zusammenfassung Es wird gezeigt und die Beobachtung vonVanbreuseghem wird wiederum bestätigt, dassKeratinomyces ajelloi keine Mikrokonidien entwickelt.

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Résumé On a démontré et confirmé de nouveau l'observation primaire deVanbreuseghem queKeratinomyces ajelloi ne produit pas de microconidies.

     

Die Epidermisskulptur als Gattungsmerkmal bei primitiven Angiospermen

Stereoscan investigations of more than 350 leaf epidermis samples fromAnnonaceae, Myristicaceae andMonimiaceae reveal that primary and secondary cuticular sculptures in some cases are stable markers on the generic level. A comparison betweenAsimina andDeeringothamnus shows the two genera to be systematically distinct but apparently closely related.

     

Zur Evolution des Parasitismus bei denScrophulariaceae undOrobanchaceae

Different growth forms and life forms of parasitic plants inScrophulariaceae andOrobanchaceae were studied from a comparative point of view. The most primitive form of parasitism is found in small, annual root parasites. Small wart-haustoria in the hypocotylar region of larger root parasites point towards a tendency of these plants to form hypocotylar tubercles as primary haustoria. Wart-haustoria also can develop on scale leaves, demonstrating an evolutionary trend towards the most advanced form of parasitism in these two families the formation of large leaf haustoria.

     

Zur Feinstruktur der Maxillarnephridien von Scutigerella immaculata Newport (Symphyla,Myriapoda)

Zusammenfassung Die Feinstruktur der Maxillarnephridien von Scutigerella immaculata Newport mit ihren drei Abschnitten Sacculus, Tubulus und Ausführgang wurde untersucht. Die Zellen des Sacculus sind typische Podocyten, an denen eine Ultrafiltration ablaufen kann. Möglicherweise wird die Filtration durch einen den Sacculus umgebenden Muskel unterstützt. Die Zellen des Tubulus zeigen basale Einfaltungen und im proximalen Teil auch Mikrovilli. Sowohl im Tubulus als auch im Ausführgang, dessen Zellen ebenfalls basale Einfaltungen aufweisen, werden Reabsorptionsprozesse vermutet.

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The fine structure of the maxillary kidney of the garden centipede, Scutigerella immaculata Newport (Symphyla, Myriapoda)

Summary The fine structure of the maxillary kidney of Scutigerella immaculata Newport (Symphyla) has been investigated. It may be compared with segmental organs of other Arthropoda having an end-sac which forms a primary urine by ultrafiltration. The filtration may be supported by a muscle surrounding the end-sac. The tubular part of the nephridium and the efferent duct show structures which may be involved in reabsorption.

     

Experimentelle Induktion sektoraler Handschwingenmauser bei adulten m?nnlichen Staren (Sturnus vulgaris)

Zusammenfassung Im Gegensatz zu den Ergebnissen früherer, unter natürlichen Photoperiodebedingungen durchgeführter Versuche, konnte unter Konstantbedingungen (LD 12 : 12) bei männlichen Staren eine Verschiebung des Mauserfocus durch Testosteronbehandlung induziert werden. Diese Befunde zeigen in Übereinstimmung mit den Freilanddaten vonEvans (1986), daß die sektorale Erneuerung der Handschwingen bei kontinentaleuropäischen Starenpopulationen als eine von mehreren Strategien zur Kompensation eines verspäteten Mauserbeginns prinzipiell vorhanden und unter bestimmten Voraussetzungen auch realisierbar ist.

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Experimental induction of eccentric primary moult in adult male European Starlings (Sturnus vulgaris)

Summary In contrast to the results of earlier studies carried out under natural photoperiodic conditions, testosterone treatment induced eccentric primary moult in male European Starlings kept in constant conditions (LD 12 : 12). These results are in line with the field data compiled byEvans (1986), and demonstrate, that skipping the first primaries in the sequence is one of several strategies to compensate for a delay of the onset of postnuptial moult in continental starling populations.

     

Quelques nouvelles données sur le phytoplancton marin et la production primaire à Tuléar (Madagascar)

Summary A list of 152 Diatoms and 158 Dinoflagellates is given and its biogeographic composition is discussed. Some quantitative data are presented: cells counts after sedimentation, spectrophotometric determination of plant pigments, and in situ primary production measurement using 14-C method. A nycthemeral study, carried out during 30 hours, shows that chlorophyll a values are highest between 15.00 and 21.00, and that photosynthesis increases from morning to evening.

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Quelques nouvelles données sur le phytoplancton marin et la production primaire à Tuléar (Madagascar)

     

Facteurs contrôlant la production primaire dens deux rivières soumises a une forte réduction de débit

The effects of river diversion on phytoplankton primary production and biomass in the downstream part of two rivers were studied in relation to physical and chemical variables. These rivers, situated north of the 52nd parallel, are characteristic of oligotrophic systems with phytoplankton primary production less than 10.76 mg C m^–2 h^–1, chlorophyll -a lower than 3.0 mg m^–3 and biomass between 118–1007 mg m^–3. The decrease in flow favored the establishment of an algal biomass approximately two times greater then that present before diversion. This increase in biomass was associated in one river with an increase of 2.5 times of the mean primary production. In the other river the primary production per unit of surface area remained stable but increased when expressed by unit volume, due to a great decrease in underwater light penetration, consequence of inorganic particular matter increase.

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Facteurs contrôlant la production primaire dens deux rivières soumises a une forte réduction de débit

     

Bimodal oxygen uptake in a freshwater air-breathing fish,Notopterus chitala

Measurements of bimodal oxygen uptake have been made in a freshwater air-breathing fish,Notopterus chitala at 29.0±1(S.D.)°C. xhe mean oxygen uptake from continuously flowing water without any access to air, was found to be 3.58±0.37 (S.E.) ml O₂ · h^?1 and 56.84+4.29 (S.E.) ml O₂ · kg^?1 · h^?1 for a fish weighing 66.92 + 11.27 (S.E.) g body weight. In still water with access to air, the mean oxygen uptake through the gills were recorded to be 2.49 ± 0.31 (S.E.) ml O₂ · h^?1 and 38.78 ± 1.92 (S.E.) ml O₂ · kg^?1 · h^?1 and through the accessory respiratory organs (swim-bladder) 6.04±0.87 (S.E.) ml O₂ · h^?1 and 92.32±2.91 (S.E.) ml O₂ · kg^?1 · h^?1 for a fish averaging 66.92±11.27 (S.E.) g. Out of the total oxygen uptake (131.10 ml O₂ · kg^?1 · h^?1), about 70% was obtained through the aerial route and the remainder 30% through the gills.     

Les cellules sensorielles des papilles de la trompe chez Glycera convoluta Keferstein (Annélide Polychète)

Résumé Chaque papille de la trompe chez Glycera convoluta contient un groupe central de deux à quatre cellules sensorielles primaires. Chaque cellule possède un noyau allongé situé à mi-hauteur de la papille. Le processus péripherique ou dendritique porte cinq à six cils qui traversent la cuticule et sont entourés chacun par un cercle de microvillosités; les cils se prolongent dans le cytoplasme par de fines racines ciliaires qui se réunissent pour former une seule énorme racine montrant une striation périodique. Le processus central ou axonal se prolonge dans le plexus nerveux sous-épithélial. Le rôle physiologique de ces cellules est discuté.

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Sensory cells of the papillae in the proboscis of Glycera convoluta keferstein (Annelida, Polychaeta)

Summary Each papilla in the proboscis of Glycera convoluta contains a central group of two to four primary sensory cells. Each one shows an elongated nucleus situated at half-height of the papilla. The peripheric or dendritic process bears five to six cilia traversing the cuticle; each of them is circled by a ring of microvilli. The cilia are prolonged in the cytoplasm by fine ciliary rootlets which gather themselves in a very big single root showing a periodic striation. The central or axonal process runs in the subepithelial nervous plexus. The physiological role of the cells is discussed.

     

Secondary cortex formation inOsmundaria prolifera (Amansieae: Rhodomelaceae)

Summary 1. The development of the pericentral cells, lateral wings, and primary cortex is briefly described in the rhodophyceanOsmundaria prolifera Lamouroux.2. During subsequent development of the blades, a large part of the outer margins of the lateral wings is lost, presumably by sand abrasion.3. The loss of the lateral wings appears to stimulate the primary cortex into meristematic activity, thereby producing a secondary cortex, attaining a thickness of up to 0.5 cm.4. Secondary cortex formation in this species produces leathery, terete stipes which may be an adaptation towards perennation.

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Entwicklung einer sekundären Rinde beiOsmundaria prolifera (Amansieae: Rhodomelaceae)

Kurzfassung Die polysiphonen Sprosse der RotalgeOsmundaria prolifera tragen an jeder Gliederzelle 5 Perizentralzellen. Mit Ausnahme der ventral gelegenen bilden die jeweils benachbarten Perizentralen je eine Reihe von Flügelzellen. Der so entstehende zweischichtige Flügelsaum wird frühzeitig von einer dicht geschlossenen, kleinzelligen Rinde eingehüllt. An den älteren Teilen des Thallus gehen die Flügelsäume verloren, wahrscheinlich werden sie durch Sand abgerieben. Dadurch dürften die primären Rindenzellen zu erneuter meristematischer Tätigkeit angeregt werden, so daß eine sekundäre Rinde entsteht; diese kann bis zu 0,5 cm dick werden. So ergibt sich die rundliche und knorpelige Achse im unteren Teil des Thallus.

     

Plasmatische Strukturen in Experimentell Hervorgerufenen Zellwandverdickungen von Micrasterias Denticulata Bréb

Zusammenfassung Mit Hilfe einer modifizierten Färbemethode nach Crafts (1931) konnte festgestellt werden, daß die bei Teilungsstadien von Micrasterias denticulata nach Turgorverminderung auftretenden Zellwandverliekungen von plasmatischen Fäden durchzogen sind. Das periphere Plasma löst sich daher trotz der Sekretion von Wandmaterial nicht vollständig von der Primärwand.Es wird die mögliche Funktion von plasmatischen Fäden unterschiedlicher Dehnbarkeit für die Form der Wandverdickung diskutiert.

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Protoplasmic structures in artificially produced cell-wall thickenings

Summary With the aid of a modified technique by Crafts (1931) it could be shown that cell-wall thickenings in Micrasterias denticulata, artificially produced by turgor-reduction during cell-growth, are penetrated by protoplasmic filaments. The outer protoplasmic layer is therefore not removed completely from the primary wall during the secretion of cell-wall material. The possible function of protoplasmic filaments differing in their extensibility is discussed in relation to the characteristic form and pattern of the wall-thickenings.

     

Understanding the gastrointestinal physiology and responses to feeding in air-breathing Anabantiform fishes

The Mekong Delta is host to a large number of freshwater species, including a unique group of facultative air-breathing Anabantiforms. Of these, the striped snakehead (Channa striata), the climbing perch (Anabas testudineus), the giant gourami (Osphronemus goramy) and the snakeskin gourami (Trichogaster pectoralis) are major contributors to aquaculture production in Vietnam. The gastrointestinal responses to feeding in these four species are detailed here. Relative intestinal length was lowest in the snakehead, indicating carnivory, and 5.5-fold greater in the snakeskin, indicating herbivory; climbing perch and giant gourami were intermediate, indicating omnivory. N-waste excretion (ammonia-N + urea-N) was greatest in the carnivorous snakehead and least in the herbivorous snakeskin, whereas the opposite trend was observed for net K⁺ excretion. Similarly, the more carnivorous species had a greater stomach acidity than the more herbivorous species. Measurements of acid–base flux to water indicated that the greatest postprandial alkaline tide occurred in the snakehead and a potential acidic tide in the snakeskin. Additional findings of interest were high levels of both PCO₂ (up to 40 mmHg) and HCO₃⁻ (up to 33 mM) in the intestinal chyme of all four of these air-breathing species. Using in vitro gut sac preparations of the climbing perch, it was shown that the intestinal net absorption of fluid, Na⁺ and HCO₃⁻ was upregulated by feeding but not net Cl⁻ uptake, glucose uptake or K⁺ secretion. Upregulated net absorption of HCO₃⁻ suggests that the high chyme (HCO₃⁻) does not result from secretion by the intestinal epithelium. The possibility of ventilatory control of PCO₂ to regulate postprandial acid–base balance in these air-breathing fish is discussed.     

Stammesspezifische Acetylierungen verschiedener Alkohole bei der Gattung Ceratocystis

Zusammenfassung An sieben Arten der Gattung Ceratocystis wird das Spektrum der wasserdampfflüchtigen Stoffe und besonders der Essigsäureester untersucht. Dabei werden prinzipielle Unterschiede in der Fähigkeit festgestellt, gewisse selbstgebildete primäre und sekundäre Alkohole zu acetylieren.Diese Untersuchungen werden auf 14 Stämme von Ceratocystis coerulescens ausgedehnt. Hier kann gezeigt werden, daß die Spezifität der Acetylierungs-reaktionen gegenüber primären und sekundären Alkoholen verschiedener Kettenlänge gewisse Rückschlüsse auf die Verwandtschaft der untersuchten Stämme zuläßt.Durch Variation der Kulturbedingungen lassen sich enge Beziehungen zwischen den Acetylierungsreaktionen und dem Citronensäurecyclus nachweisen.

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Strain-specific acetylation of different alcohols in the genus Ceratocystis

Summary The steam-volatile products, especially the acetylated alcohols, of 7 Ceratocystis-species were analyzed. There are fundamental differences in the ability for acetylation of certain primary and secondary alcohols.These studies were extended to 14 strains of Ceratocystis coerulescens. From the specifity of the acetylation reactions concerning primary and secondary alcohols of different chainlength, certain conclusions can be drawn on the relationship between the strains of this study.By variation of cultural conditions it has been possible to show close connections between the acetylation reactions and the tricarboxylic acid cycle.

     

Differenzierungsvorgänge in der keimenden Gemmula vonEphydatia fluviatilis

Zusammenfassung Die beschalten Dauerstadien (Gemmulae) des SüßwasserschwammesEphydatia fluviatilis enthalten uniforme, totipotente Statocyten (Thésocyten), aus denen sich im Keimungsverlauf Archaeocyten (ein- und zweikernige) und Histoblasten differenzieren. Letztere treten nach einem gewissen Inkubationszeitraum in der zapfenartigen Zone unter der Mikropyle auf, während sich die übrigen Zelltypen zu einem an der Schalenöffnung orientierten, dreidimensionalen Muster gefälleartig anordnen.Nach Ausbildung eines einschichtigen Pinacocyten-Epithels (primäres Pinacoderm) aus peripher gelegenen, einkernigen Zellen schlüpft das nunmehr im Kapselinneren entstandene Primordium durch die offene Mikropyle und nimmt mit dem Substrat Verbindung auf.Das Primordium entwickelt sich zum frühen Jungschwamm, in den die restlichen Archaeocyten, Histoblasten und auch vereinzelt Skleroblasten einwandern.

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Differentiation processes in the germinating Gemmula ofEphydatia fluviatilis

Summary The dormant shelled gemmulae of the fresh water spongeEphydatia fluviatilis contain uniform, totipotent statocytes (thésocytes), which can differentiate either into archaeocytes (mono- and binucleated) or into histoblasts. The histoblasts accumulate at the villus near the micropyle. The other cell types orientate in a three-dimensional pattern at the micropyle, according to a developing gradient.After the primary pinacoderm is formed, the sponge primordium is released through the open micropyle. The primordium develops into a new sponge, into which archaeocytes, histoblasts and scleroblasts migrate.

     

Über die Primärwindungen menschlicher Chromosomen

Zusammenfassung In Routinepräparat befinden sich 70–80% der Chromosomensätze im Stadium der Metaphase. Die Zahl der Coils pro Chromosom ist konstant. Nach Zählung der Windungen kann danach karyotypiert werden. Die Zahl der Windungen bei Prophasechromosomen ist größer, die der Anaphasechromosomen kleiner. Die Ganghöhe ist in diesen drei untersuchten Stadien der Mitose konstant=0,55 (±0,15 ).

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The primary coils of human chromosomes

Summary In a routine chromosome preparation 70–80% of chromosome sets are at the stage of metaphase. The number of coils per chromosome is constant. Karyotyping is possible on the basis of the number of primary coils. There are more primary coils in chromosomes at the stage of prophase and less in chromosomes in anaphase. The pitch is constant in all three stages of mitosis examined=0.55 (±0.15 ).