Reduction of potassium tellurite by Candidas

Summary A technique for observing the reduction of potassium tellurite byCandidas was developed. Various species of these yeasts reduce it at different concentrations, but that which is most useful for differentiation is 0.02 % added to Sabouraud dextrose agar basal medium. Of the yeasts studied,C. albicans, C. parapsilosis andC. tropicalis all reduced potassium tellurite to the concentration mentioned before, while the growth ofC. krusei, C. parakrusei andC. pseudotropicalis was inhibited. Without exception,C. pseudotropicalis reduced this salt at lower concentrations. The two strains ofC. guilliermondii tested gave contradictory results: one of them grew and reduced potassium tellurite, while the growth of the other was inhibited.Professor of Microbiology.     

Zur Morphologie der braunen Inguinaldrüse des Kaninchens

Zusammenfassung Die braune Inguinaldrüse des Kaninchens ist eine einfach gebaute tubulöse Drüse. Das Epithel der Drüsenschläuche ist einschichtig kubisch bis hochzylindrisch und wird von spindelförmigen Myoepithelzellen unterlagert. Die Drüsenzellen besitzen nahezu organellenfreie, fein granulierte Cytoplasmaprotrusionen, die weit in das Lumen hineinragen; in der Lichtung werden häufig isolierte Cytoplasmabereiche gefunden. Der Sekretionsmodus ist somit deutlich apokrin (decapitation secretion).Das endoplasmatische Retikulum ist überall in der Zelle zu erheblich zerklüfteten Cisternen erweitert; Golgi-Apparate sind spärlich. Große, matrixreiche Mitochondrien zeichnen sich durch Armut an Cristae aus. Elektronendichte Sekretpfützen liegen vornehmlich supranukleär; Sekretvakuolen kommen nicht vor.

---

On the morphology of the brown inguinal gland of the rabbit

Summary The tubular brown inguinal glands of the rabbit have been studied by light and electron microscopy. The apocrine secretory cells are columnar elements with prominent apical cytoplasmic caps and protrusions extending into the glandular lumen. These protrusions contain neutral mucopolysaccharides demonstrable by light microscopy. The secretory cells are characterized by the presence of large mitochondria with scant cristae and an electron dense matrix. Electron dense plaques, presumably secretory masses, are present in the supranuclear cytoplasm. The cytoplasm contains cisternae of a granular endoplasmic reticulum. Myoepithelial cells are situated between the secretory cells and the basal lamina.

---

---

Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Neue Befunde zur Beschaffenheit des basalen Labyrinthes im Nierentubulus

Zusammenfassung Normale Rattennieren werden von der Aorta her mit Ferritin-Lösung perfundiert. Bei einer Versuchsgruppe wird die Nierenvene während der Perfusion abgeklemmt und die Ferritin-Infusion unter Überdruck kurzfristig fortgesetzt, wobei eine deutliche Volumenzunahme des Organes eintritt. Noch während der Perfusion wird durch Auftropfen von Osmiumtetroxydlösung auf die Nierenoberfläche fixiert.Die elektronenmikroskopische Untersuchung subkapsulär gelegener Tubuluskonvolute führt zu folgenden Ergebnissen: 1. In den Nieren ist nach Ferritin-Infusion unter Überdruck eine größere Ferritin-Menge durch die Wand der peritubulären Kapillaren in das Interstitium und in das interzelluläre Labyrinthsystem des Tubulusepithelwalles — bis an die Zonula adhaerens der Schlußleistenkomplexe — vorgedrungen. Damit erweist sich das Labyrinth-system als einheitlicher Diffusionsraum. 2. Regelmäßig ist in das Labyrinth des distalen Tubulus mehr Ferritin eingeströmt als in das des proximalen, wobei eine Erweiterung der Labyrinthspalten gegenüber den Kontrollen nicht festzustellen ist. 3. Bei Ferritin-Perfusion ohne Erhöhung des hydrostatischen Druckes in den peritubulären Kapillaren bleibt der Einstrom in das Labyrinth aus.In intravitalfixierten Kontrollnieren zeigen die interzellulären Labyrinthspalten des proximalen und des distalen Tubulus eine ziemlich konstante, aber unterschiedliche Weite (proximal 19,8±2,9 nm, distal 32,7±2,3 nm). Mikrodensitometrisch wird innerhalb der Labyrinthspalten die gleiche durchschnittliche Dichte registriert wie im Grundplasma des intravitalfixierten Tuhulusepithels. Es wird angenommen, daß das Labyrinthsystem eine organische Interzellularsubstanz enthält, deren funktionelle Bedeutung weiterer Klärung bedarf.

---

Summary Using a solution of ferritin an arterial perfusion was carried out in rat kidneys, until the blood had left the renal vascular system. Then the renal vein was clamped and the arterial infusion with ferritin was continued. During this procedure we intensified the pressure of the arterial infusion, until the volume of the kidney has been increased significantly (about factor 1.5). Under these conditions the kidney cortex was fixed in situ by dripping of OsO₄-solution on the surface of the organ. Electron microscopic studies of subcapsular convoluted tubules led to following results:1. Numerous ferritin molecules have left the lumen of the peritubular capillaries passing the pores of the endothelium, both the endothelial and the epithelial basement membrane and finally they have gained access to the intercellular spaces (basal labyrinth) of the tubular epithelial wall. By this the ferritin molecules could be located directly below the zonula adhaerens of the junctional complex. 2. Constantly more ferritin rushed into the labyrinth of distal than into that of proximal tubules. The labyrinth spaces containing ferritin are not widened in comparison with these of control tubules. 3. In additional perfusion experiments without ligature of the renal vein and without increased hydrostatic pressure no inrush of ferritin into the basal labyrinth had been observed. Therefore it can be concluded that the inrush of ferritin into the intercellular labyrinth is a consequence of an elevated hydrostatic capillary pressure during the infusion.In control kidneys fixed in vivo using isotonic OsO₄-solution (by dripping on the surface of the kidney or by tubular microperfusion) the intercellular spaces of both proximal and distal convoluted tubules show a rather constant, but different width (proximal 19.8±2.9 nm, distal 32.7±2.3 nm). Morphological and microdensitometric findings demonstrate within the intercellular labyrinth spaces the same average density as in the groundplasm of the intravital fixed tubular epithelium. It is suggested that the labyrinth system contains an organic intercellular substance the functional significance of which is not yet clear and must be further investigated.

---

---

Auf die Befunde an den peritubulären Kapillaren bei Ferritin-Durchtritt soll im Rahmen dieser Arbeit nicht näher eingegangen werden.     

Zur Biologie,Morphologie und Verhaltensweise von Apion virens Hrbst. (Col., Curculionidae)

Zusammenfassung Die vorliegende Arbeit soll einen Beitrag zur Monographie von Apion virens liefern. Von den einzelnen Stadien werden die Entwicklungsdauer sowie verschiedene morphologische Einzelheiten angegeben. Die Lebensdauer der Imagines beträgt 11–12 Monate, wobei die Käfer allerdings während der Überwinterung Nahrung aufnehmen müssen.Die Ausfärbung der Puppen und Imagines erfolgt progressiv. Der Fortgang dieser Prozesse wird im einzelnen beschrieben.Die Zahl der abgelegten Eier betrug maximal 166/.Untersuchungen zur Phänologie ergaben verschiedene gut abtrennbare Phasen im Laufe des Jahres.Im Wirtspflanzenspektrum der Art spielen Trifolium-Arten die wichtigste Rolle.Die Vorzugstemperatur- und-lichtbereiche zeigen charakteristische Veränderungen ihrer Lage im Laufe des Jahres. Dabei ergeben sich hinsichtlich der Temperatur auch Unterschiede zwischen und .Von den Verhaltensweisen der Imagines werden Kopulation, Eiablage und Putzhandlungen eingehend beschrieben.

---

On the biology, morphology and behaviour of apion virens Hrbst. (Col., Curculionidae)

Summary This paper intends to give a contribution to a monography of Apion virens. From the different stages the duration of development and some details of the morphology are presented. The longevity of the adults reaches 11 to 12 months when uptake of food during hibernation is possible.The pigmentation of pupae and adults, which is described in detail, takes place progressively.The maximum number of eggs per female was 166.Investigations about the phenology showed several well separated phases in the course of one year. Trifolium species are the most suitable host plants of A. virens.The range of preference of temperature and humidity changes characteristically during the year. — Between and there exist also differences in the optimum temperature range.Copulation, egg-laying and cleaning behaviour are described in detail.

     

A comparative study of the chromosomes in the incipient species of the Drosophila paulistorum complex

Summary Drosophila paulistorum Dobzhansky et Pavan is a complex of six races or incipient species. The races are mostly allopatric, but they are reproductively isolated sufficiently to permit them to exist also sympatrically in some places. The gene arrangements in the chromosomes of the races have been compared by means of examination of the giant chromosomes in the larval salivary glands; 28 strains of all races, and about an equal number of interracial hybrids have been studied.Chromosomal inversion polymorphism has been discovered in all races, even in the Guianan race of which only a single strain is available. Inversion heterozygotes are found in every one of the five chromosomal strands which the species has. Interracial hybrids tend to be heterozygous for more inversions than are present in the strains of the parental races. The Transitional race has however much the same gene arrangements as the widespread Andean — South Brazilian race.With the exception of the Transitional race, and of three other possible exceptions, each race has a collection of its own race-specific inversion polymorphs, not found in the other races. This very striking finding is discussed in connection with the hypothesis which envisages the origin of new species from marginal colonies at the periphery of the geographic distribution area of the ancestral species.The work reported in this article has been carried under Contract No. AT-(30-1)-1151, U.S. Atomic Energy Commission, mostly at the Department of Zoology, Columbia University, New York.     

Cytological and autoradiographic studies in Sciara coprophila salivary gland chromosomes

Summary Morphological and metabolic changes on the salivary chromosomes of Sciara coprophila were followed during the later half of the fourth larval instar.Cytological maps were prepared for five successive stages from mid-fourth instar to the prepupal stage. These maps, which constitute a revision of those published earlier by Crouse, summarized our cytological findings and were the basis for studies on DNA replication of these chromosomes.Similar to earlier studies in Chironomidae, differences in the puffing pattern were noted between the anterior and the posterior portions of the salivary gland. The most striking difference was noted in region 2B on chromosome III which produces a large puff only in nuclei from the anterior part of the gland. Other autosomal puffs, although present in both parts of the gland, showed constant differences in size.An increase in the number of bands from mid-fourth to late fourth instar was observed. The new bands are all of the light-staining kind.In Sciara the puffed area may include a large number of bands in addition to the bands which originated the puff. The maximal extent of puffs was determined in terms of chromosomal map regions and the number of bands subject to obliteration.In the autoradiographic experiments use was made of H³-thymidine as DNA precursor. The aim of these studies was to detect any asynchronies in the replication time of bands. In fact, marked differences in the relative rates of uptake of H³-thymidine of a number of bands in a certain proportion of chromosomes have been observed, while others showed uniform incorporation. Since these latter were found with higher frequency the period of uniform labeling must comprise a larger part of the replication cycle then the periods of localized labeling. To assess the validity and constancy of the observed patterns of unequal incorporation, a semiquantitative analysis was carried out. It showed that the bands showing localized uptake may be separated into two broad groups. In one of these groups are the centromere regions and certain chromosomal ends, which are presumably heterochromatic. The other group comprises most of the puff sites and bulbs. Since late replication is characteristic of heterochromatin, we assumed that bands of the former group (C) replicate late in the cycle, while puffs and bulbs start replication early, and the period of equal labeling is intermediate. Other intermediate labeling patterns were observed and are described.It is known that in the fourth instar from two to three DNA replications occur in the salivary gland nuclei, the last of which coincides with puffing. Several stages may be distinguished in the puffing process based on morphology and rates of isotope uptake of the puffs. The first sign of puffing is a very high rate of incorporation at puffs. It is maintained throughout this last DNA synthesis period and only declines when all other chromosomal regions have ceased to replicate. A pattern of high and exclusive uptake at the heterochromatic sites (pattern C) was never observed in this replication; instead puffs are the last regions to terminate DNA synthesis.These results are discussed in relation to several current problems, such as, asynchronous DNA replication, the problem of metabolic DNA, and the concept of the heterochromatic state.Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, in the Faculty of Pure Science, Department of Zoology, Columbia University, New York. This work has been supported by U.S. Public Health Training Grant No. 2Tl-GM-216-05; partial support has been received also from Grants GB 42 and G-14043 from the National Science Foundation to Dr. H. V. Crouse.     

Elektronenmikroskopischer Beitrag zur Differenzierung des Ependyms am Rückenmark von Hühnerembryonen

Zusammenfassung Am Rückenmark von 2, 3, 41/2, 51/2, 8, 81/2, 9, 13 und 16 Tage alten Hühnerembryonen wurde die Ependymdifferenzierung des Zentralkanals elektronenmikroskopisch untersucht und mit den Befunden bei jungen Küken verglichen. Die Ependymentwicklung geht von den undifferenzierten neuroektodermalen Matrixzellen aus, führt über die primitiven und polaren Glioblasten (die Spongioblasten der älteren Literatur) zu den Ependymoblasten und schließlich zu den reifen Ependymzellen. Elektronenmikroskopisch gelingt der Nachweis, daß die Entwicklung der Ependymzellen nicht nur mit charakteristischen Gestaltänderungen, sondern auch mit typischen Veränderungen der Zytoplasmafeinstruktur verbunden ist. Dabei zeigen sich Unterschiede zwischen den zentralen (apikalen) und den peripheren (basalen) Fortsätzen. Allen diesen Zellen ist eine sich immer mehr aufprägende Bipolarität eigen. Vor allem die polaren Glioblasten haben schon eine starke Polarisierung, erkennbar an den Unterschieden der zentralen und peripheren Fortsätze. Die apikale Zytoplasmadifferenzierung wird beherrscht von der Bildung zahlreicher Mikrovilli und Zilien an der freien Oberfläche und einer durch die quantitativen Veränderungen der Zellorganellen gekennzeichneten Zytoplasmaaktivierung. An den peripheren Fortsätzen kann schon im ersten Drittel der Embryonalperiode die Synthese von Gliafilamenten beobachtet werden, was auf die später immer deutlicher werdende gliöse Differenzierung hinweist. Die elektronenmikroskopischen Befunde erlauben den Schluß, daß die Entwicklung des Ependyms einem bipolaren Differenzierungstyp entspricht. Auf die entwicklungsgeschichtlichen elektronenmikroskopischen Untersuchungen am Ventrikelependym wird vergleichend eingegangen. Funktionelle Aspekte der embryonalen Ependymzellen werden nur am Rande berührt.

---

Summary An electronmicroscopic study of the ependymal differentiation and the development of the central canal has been carried out on the spinal cord of chicken embryos incubated for 2, 3, 41/2, 51/2, 8, 81/2, 9, 13 and 16 days old. The ependymal cells arise from the undifferentiated matrix cells. The first stage of differentiation is the formation of primitive and polar glioblasts (spongioblasts) in the region of the basal and roof plates. The fine structure of the polar glioblasts differs in the regions of the internal processes, the perikarya and the long processes extending towards the surface of the neural tube. The cytoplasmic differentiation within the internal region of these glioblasts is characterized by the development of diverse microvilli and of cilia on the surface, the accumulation of mitochondria and the development of a prominent Golgi apparatus in the cytoplasm. The synthesis of glial filaments occurs only in the peripheral processes. In the region of the perikaryon there are numerous free ribosomes and some profiles of a granular endoplasmic reticulum. The differentiation of the polar glioblasts into ependymal cells leads to a modified bipolar glial-epithelial structure. On the other hand, the transformation of the polar glioblasts into migrating glioblasts and finally into protoplasmatic and fibrous astrocytes—studied in the region of the glial septum dorsale—is characterized by a retraction of the internal processes with loss of epithelial differentiation. During all stages of development the ependymal cells retain their basic bipolarity, but time-related modifications of this nature can be observed.