Effect of neurectomy on nuclease activity in skeletal muscles of rats

Author followed up the activity of the three enzymes involved in the catabolism of nucleic acids--acid deoxyribonulease (DNase II), alkaline ribonuclease (RNase I), and acid ribonuclease (RNase II)--in the denervated gastrocnemius and soleus muscles of rats for 28 postoperative days. The activity of both acid nucleases increased in both types of denervated muscles, compared with the respective controls. Up to the 14th postoperative day, the activity excess of both acid nucleases was more significant in the m. gastrocnemius than in the m. soleus. The RNase I ran below the control activity during the whole period in the m. soleus and up to the 14th day in the m. gastrocnemius. The role of nucleases and nuclease inhibitors in the changes of nucleic acid catabolism in neurogenic muscular atrophies is discussed.     

The effect of increasing glucose in CPD on the quality of stored blood

Changes in quality of blood units containing one and a half or double amounts of glucose, stored at +4 degrees C for three weeks were analysed. An experimental preservative containing glucose and fructose (1 : 1) was also used. No other additives (purine or purine-nucleoside) were applied. A standard CPD preservative of the National Inst. of Haematology and Blood Transfusion was used as control. The pH, plasma free haemoglobin, K+ content, red blood cell (RBC) ATP and 2,3-DPG content, and RBC fragility index were determined in each sample. Increase of glucose concentration, the addition of fructose had a beneficial effect on blood pH, and on plasma free haemoglobin and K+ concentration. 150% glucose improved the 2,3-DPG maintenance in stored blood.     

Vacuolar localization of wound-induced carboxypeptidase inhibitor in potato leaves

The wound-induced carboxypeptidase inhibitor in potato leaves was shown to be localized in the central vacuoles of the cells. The inhibitor was quantified by immunological assays (ELISA) in protoplasts and vacuoles isolated from upper unwounded leaves of 5- to 6-week old potato plants that had been wounded on their lower leaves 48 hours earlier to induce the accumulation of the carboxypeptidase inhibitor. The regulation of the synthesis and compartmentation of the inhibitor is similar to that of wound-induced serine proteinase Inhibitors I and II in potato and tomato leaves and appears to be part of an induced defense response against attacking pests.     

Suppressor mutations identify box9 as a central nucleotide sequence in the highly ordered structure of intron RNA in yeast mitochondria.

Data presented here lend support to the notion that RNA splicing in yeast mitochondria depends on the formation of hybrid structures involving the well-conserved intron sequences box9 and box2. Starting with the cis-dominant splicing-defective box2 mutant G2590, a G----A transition, we isolated a revertant having a mitochondrial second site suppressor mutation, which restores splicing competence in the presence of the original mutation. Sequence analysis reveals that the suppressor mutation is a C----T transition in box9(5' part). This second mutation compensates for the first one in box2 and restores a box2/box9(5') hybrid. Combined with previous data demonstrating an interaction of the adjacent sequence box9(3' part) with the upstream box9c sequence in intron 4, the central role of box9 in the formation of the intron 4, the central role of box9 in the formation of the intron 4 RNA high order structure becomes evident.     

Processing of yeast mitochondrial RNA: involvement of intramolecular hybrids in splicing of cob intron 4 RNA by mutation and reversion

Revertants have been obtained from six mutants of the box9 cluster, which are supposed to be defective in RNA splicing as a result of alterations in a splice signal sequence. This sequence is in the 5' part of intron 4 of the cob gene, 330 to 340 bp downstream from the 5' splice site. Sequencing reveals that reversion to splicing competence is achieved by restoration of the wild-type box9 sequence; by creation of novel box9 sequences; and by introduction of a second site or suppressor mutation (sup-) compensating for the effect of the primary box9- mutation. The sup- mutation alters a sequence in intron 4,293 bp upstream from the box9- primary mutation. The box9 sequence and this upstream sequence can base pair to form an intramolecular hybrid in intron RNA in which box9- and sup- are compensatory base pair exchanges (G----A and C----U, respectively). Thus intramolecular hybrid structures of intron RNA are essential for RNA splicing.     

Funktionelle Morphologie des Geruchsorgans und Histologie der Kopfanhänge der NasenmuräneRhinomuraena ambonensis (Teleostei,Anguilliformes)

Zusammenfassung 1. An drei, wahrscheinlich adulten Exemplaren der Nasenmuräne,Rhinomuraena ambonensis Barbour, wurden die funktionelle Morphologie des Geruchsorgans sowie dessen Histologie und die der bartelartigen Kopfanhänge untersucht.2. Die Ränder der vorderen Riechöffnungen sind zu trichterförmigen Hautlappen ausgewachsen. Die in ihrer Ausrichtung und Form durch Körperbewegungen kaum beeinflußbaren Trichter leiten auch im Ruhezustand des Tieres Wasser in die Riechhöhle, da ihre weite Öffnung im Strömungsbereich des Atemwassers liegt. Auf diese Weise erfolgt eine effektive Ventilation der Riechhöhle.3. Im mehrschichtigen Epithel der Trichter liegen Sekretzellen und vereinzelt Sinnesknospen; unmittelbar über den Epithelbildungszellen verlaufen Nervenfasern. Im Bindegewebe, das beidseitig von Epithel bedeckt ist, liegen Gefäße, Nervenbündel (Nervus trigeminus) und Pigmentzellen. Muskelgewebe fehlt. Neben dem Bindegewebe gibt es kein anderes Stützgewebe.4. Die beiden Riechhöhlen sind von extremer Ausdehnung. Die Zahl der lamellenartigen Riechfalten, die in zwei Doppelreihen nach dem 90°-Typ liegen, beträgt ca. 200. Zwischen den Innenrändern der Falten einer Doppelreihe, dorsal von der Mittelraphe, erstreckt sich eine zylindrische Rinne, die der Duftwasserpassage dient.5. Die Riechfalten sind bis auf die lateralen, dorsalen Teile und Teile der ventralen Faltenansätze kontinuierlich mit Riechepithel bedeckt. Der histologische Aufbau des Riechepithels entspricht dem des Aals. Die Rezeptorendichte schwankt zwischen 2–3×10⁴ pro mm². Im Verhältnis zur Riechhöhlenausdehnung ist die Riechfeldgröße erheblich.6. Tuscheexperimente zeigten, daß — ausgelöst durch die in die Längsrinne der Riechhöhle ragenden fingerförmigen Innenränder der Riechfalten — Mikroturbulenzen entstehen, die neben der Flimmerbewegung durch Kinocilien für die Mikroventilation des Faltensystems sorgen.7. Das auf der Symphyse des Oberkiefers zwischen den Trichterbasen sitzende Rostrum ist eine Hautprojektion, deren bindegewebiger Zentralteil ein mehrschichtiges Epithel trägt. Im Bindegewebe sind Gefäße, feine Nerven und Pigmentzellen eingebettet. Im Epithel finden sich geschmacksknospenähnliche Sinnesorgane. Prinzipiell haben die drei Mandibularbarteln den gleichen histologischen Aufbau wie das Rostrum. Auch ihr Epithel weist Sinnesknospen auf, die wie jene des Rostrums und der Trichter vielleicht als chemische Sinnesorgane beim Nahrungstest fungieren.8. Nach dem Ergebnis vorliegender Untersuchungen wirdRhinomuraena ambonensis in die Gruppe der makrosmatischen Knochenfische eingereiht.

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Functional morphology of the olfactory organ and histology of the head appendages of the moray eelRhinomuraena ambonensis (Teleostei, Anguilliformes)

In three individuals of the moray eelRhinomuraena ambonensis (Barbour), the functional morphology and histology of the olfactory organ as well as the histology of the different head appendages were investigated. The edges of the anterior nares are extremely extended, forming a funnel-like wide opening through which the odour water passes. Even when the fish does not move, an effective ventilation of the olfactory chambers is maintained by a permanent water current towards the funnel opening induced by the peristaltic movements of the musculature of the gill chamber (principle ofBernoulli). The histological structure of the head appendages (funnels, rostrum and mandibulary barbels, which are all skin projections) is described. The epithelia of all these appendages bear sensory organs which are similar to taste buds. The two olfactory organs are of extremely large size. Each chamber contains about 100 olfactory lamellae which are arranged in two lines (90°-type;Holl 1965). A cylindrical cavity extends between the inner edges of the olfactory lamellae through which the water runs to the posterior nare. Interlamellar microventilation is produced by numerous turbulences which are caused by the edges of the olfactory lamellae and by the kinocilia of the olfactory epithelium. The histological structure of the olfactory epithelium is similar to that ofAnguilla anguilla. The different results demonstrate thatRhinomuraena ambonensis is probably a macrosmatic fish.

     

Isolation and biochemical characterization of fusicoccin-insensitive variant lines of Arabidopsis thaliana (L.) Heynh

Arabidopsis thaliana lines have been isolated that are insensitive to the fungal toxin fusicoccin (FC). Initial screening was done by selecting for plants that either grew well on high concentrations of FC or did not respond to FC by increases in H⁺-extrusion. All selected plants were tested, in several additional rounds of screening, for binding to microsomal proteins of a ³H-labeled radioligand of fusicoccin. A novel assay allowing for the direct selection of individual plants exhibiting reduced binding of FC was developed and used as screening procedure. Independent variant lines (43) with stably expressed, reduced binding of FC were isolated and subjected to a detailed characterization of their binding sites. The lines could be subdivided into several distinct classes with respect to these characteristics. In class-I lines, the data indicate a partial conversion of high-affinity binding sites to a low-affinity state. In class-II lines, the affinity of the binding site to FC is strongly reduced while the number of sites, as well as several other biochemical parameters, is completely unchanged, suggesting a specific alteration in the properties of the fusicoccin-binding protein. In class-III lines, the ligand-binding protein complex, while retaining its high affinity, is destabilized at supraoptimal concentrations of FC (such as those used for screening). In wild-type plants, only the high-affinity binding site was detected. Combined, these data prove that the high-affinity sites represent the plant's FC receptor.Abbreviations A_o binding site concentration - FC fusicoccin - FCBP fusicoccin-binding protein - FCol 9-nor-8-hydroxyfusicoccin - K_D dissociation constant of the FCBP-radioligand complex We are grateful to Iris Sandorf and Gudrun Henrichs for excellent technical assistance. This work was supported by the Deutsche Forschungsgemeinschaft, Bonn, Germany and by Fonds der Chemischen Industrie (literature provision).