Cell differentiation and pigment composition in Anabaena cylindrica

Summary Cell differentiation in Anabaena cylindrica is accompanied with characteristic changes in the pigment composition of heterocysts and spores. In both the absence of phycocyanin is consistent with the lack of CO₂-fixing ability previously reported. The presence of chlorophyll and -carotene suggests a functional photosystem I in heterocysts. In the spores chlorophyll is largely replaced by pheophytin. The quantitative distribution of carotenoids is also affected. An increase in the proportion of -carotene is characteristic of heterocysts while spores show a larger proportion of xanthophylls compared with the intact filament.     

Beobachtungen zur fortpflanzungsbiologie und zum verhalten der geißelspinne tarantula marginemaculata C. L. Koch (Chelicerata,Amblypygi)

The social behaviour of T. m. includes ritualized fights. Sperm transfer is achieved by means of a spermatophore deposited on the ground and by the male pulling the female over it. The behaviour and the spermatophore are described and compared to those of other arachnids and the phylogenetical implications are discussed.     

Die Feinstruktur der peribronchialen Mikroparaganglien beim Meerschweinchen

Zusammenfassung Das Parenchym der peribronchialen Mikroparaganglien wird von zwei Zellarten aufgebaut: Chromaffine Zellen (Typ I-Zellen) und Hüllzellen (Typ II-Zellen).Die chromaffinen Zellen sind durch ihren reichen Gehalt an Vesikeln mit elektronendichtem Inhalt gekennzeichnet, deren Durchmesser 700–1300 Å beträgt. Markfreie Nerven ziehen an die Typ I-Zellen heran und bilden synaptische Kontakte aus. Die chromaffinen Zellen sind dabei der postsynaptische Teil der Verbindung. Die Hüllzellen entsprechen strukturell und funktionell den Schwannschen Zellen.Ein Mikroparaganglion wird von 10 bis 15 chromaffinen Zellen und deren Hüllzellen aufgebaut. Sie liegen dicht um fenestrierte Kapillaren, die von den Aa. bronchiales aus versorgt werden. Die Paraganglien sind von den Nervenzellen des peribronchialen Plexus durch dessen Perineurium getrennt. Selten findet man solitäre chromaffine Zellen innerhalb der Nervengeflechte. Es wird angenommen, daß die Paraganglien endokrine Funktionen erfüllen.

---

The fine structure of the guinea pig peribronchial micro-paraganglia

Summary The parenchyma of peribronchial microparaganglia consists of two different cell types: chromaffin cells (type I-cells) and surrounding cells (type II-cells).The chromaffin cells contain numerous vesicles with electron dense content, their diameter ranging from 700 to 1,300 Å. Unmyelinated nerves form synapses with type I-cells. The surrounding cells structurally and functionally correspond to Schwann cells.A micro-paraganglion consists of ten to fifteen chromaffin cells and their satellite cells. They are situated close to fenestrated capillaries, which are supplied from the Aa. bronchiales. A perineurial sheath separates the paraganglia from the nerve cells of the peribronchial plexus. Single chromaffin cells are found seldom within the nervous plexus.The paraganglia are thought to have an endocrine function.

     

Biology of budding bacteria

Summary Budding bacteria from aquatic or terrestrial habitats were found to accumulate ferric oxide hydrate (ferric hydroxide) on their cell surfaces. Metal paper clips served as the source of oxidizable iron. Pure cultures deposited ferric hydroxide during growth on sea water medium at a pH of 7.8, but not in a mineral salts medium of normal ionic strength, of pH 7.2, and without NaCl, although some active strains came from fresh water or soil.Ferric iron deposition was found to be initiated at primary active sites on the cell surface; the hyphae and rods eventually become completely encased by the heavy coat.The presence of iron depositing, budding bacteria in fresh water, brackish water or sea water indicates an ubiquitous distribution of these microorganisms.Actively depositing isolates from marine environments are more closely related to Pedomicrobium than to Hyphomicrobium spp. because of their multiple formation of hyphae from rod-shaped swarmer cells. A taxonomic and cultural study of these new forms is in progress.     

Über die Lokalisierung der Saccharoseaufnahme bei Submersmycel von Aspergillus niger

Zusammenfassung Junges Submersmycel von Aspergillus niger ist in seiner ¹⁴C-Saccharoseinkorporation uneinheitlich. Weiterhin konnte gefunden werden, daß die Saccharoseaufnahme gleichmäßig über die Hyphen junger Pellets erfolgt. Eine verstärkte radioaktive Markierung der Hyphenspitze nach längerer Inkubation ist die Folge des Spitzenwachstums. Altes Mycel verhält sich anders. Hier sind Orte intensiven Stoffwechsels proliferierende Conidienträger.

---

On the localization of the sucrose uptake by submerged Aspergillus niger mycel

Summary It was found, that joung pellets of Aspergillus niger are inhomogen in relation to the incorporation of ¹⁴C-sucrose. In joung pellets the uptake takes place uniformly over the surface of the hyphae. With extending of the incorporation time the radioactivity was localized mainly in growing tips of the hyphae. Growth centres in old pellets are not the hyphae but the proliferating conidiophores.

     

Weitere Untersuchungen zur phytochrominduzierten Akkumulation von Ascorbinsäure beim Senfkeimling (Sinapis alba L.)

Summary The accumulation of ascorbic acid (AS) in the young mustard seedling is greatly increased by the action of the active form of phytochrome (P₇₃₀) (see Schopfer, 1966). There is no photosynthesis in continuous far-red light, which was used throughout the experiments. The phytochrome-mediated increase in AS approximately parallels the synthesis of anthocyanin in the seedling, although the onset of AS-accumulation precedes the anthocyanin synthesis by 2–3 hours (Fig. 4 and 5).—The action of P₇₃₀ increases the amount of AS in every part of the seedling (cotyledons, hypocotyl, radicula) (Fig. 1–3). This increase in AS parallels the formation of P₇₃₀ rather than the different growth responses of these organs (enlargement of the cotyledons, inhibition of hypocotyl and radicula lengthening). The lag in AS-accumulation after onset of far-red irradiation is the same in all 3 parts of the seedling (about 1 hour under the experimental conditions; Fig. 4).—Actinomycin D (10 g/ml), which strongly inhibits anthocyanin synthesis (Fig. 9 and 10), has no corresponding effect on P₇₃₀-dependent increase in AS-accumulation (Fig. 7 and 8). This result support the hypothesis that already active genes are only slightly influenced by actinomycin D (see Lange and Mohr, 1965). It also shows that, in contrast to its role in anthocyanin synthesis, P₇₃₀ probably does not act by initiating potentially active genes in the case of AS-accumulation. — A dark synthesis of anthocyanin in the cotyledons can be obtained by application of AS to the seedlings (Fig. 11). Glucose and sucrose are ineffective in this respect (Table 2). The effect of AS-feeding on anthocyanin synthesis can be inhibited by actinomycin D in very much the same way as light induced anthocyanin synthesis is inhibited (Table 3). — Also the RNA content of the cotyledons is increased by feeding AS in the dark (Table 4).These results are in line with the earlier suggested hypothesis (see Schopfer, 1966) that increase in AS-accumulation is a very early event in the mediation of some positive photoresponses, e.g. anthocyanin synthesis. According to the hypothesis of Mohr (1966 a, b) it has been concluded that AS functions as a part of the signal chain of phytochrome-mediated photomorphogenesis. This signal chain is thought to start differential gene activation to bring about positive photoresponses.