Flavonoids and coumarins from Platymiscium praecox

The wood of Platymiscium praecox Mart. (Leguminosae-Lotoideae) contains sitosterol, 4,2′,4′-trihydroxychalcone, (2R)-7-hydroxyflavanone, (±)-7,4′-dihydroxyflavanone, (2S, 3S)-3,7-dihydroxyflavanone, 3,7-dihydroxyflavone, 3,7,4′-trihydroxyflavone, 6,7-dihydroxy-4′-methoxyisoflavone and 6,7-dimethoxycoumarin. It also contains three novel compounds: 7-hydroxy-4-methoxy-5-methylcoumarin, 7-O-glucosyloxy-4-methoxy-5-methylcoumarin and 7-hydroxy-4,8-dimethoxy-5-methylcoumarin.     

New Technique for Biotyping

An efficient technique for biotyping, using disposable trays instead of glass tubes and agar instead of liquid media, is described.     

Escherichia coli O Antigen Typing by Means of a Mechanized Microtechnique

A mechanized microtechnique for the serological typing of Escherichia coli cultures is described.     

Substances with cytokinin activity extracted from growing apices of apple-tree shoots

The presence of native cytokinins was studied in growing apices of apple-tree annual shoots. During June the presence of two compounds showing cytokinin activity in biotest was observed and their R_F value was determined in three chromatographic systems.     

Turnover of mucopeptide during the life cycle ofBacillus megaterium

Sporogenic and asporogenicBacillus megaterium strains, as well asBacillus cereus degraded the murein component of the cell wall labelled with¹⁴C-diaminopimelic acid to TCA-soluble compounds during growth. The rate of murein turnover was about 15% during one generation in all three cases. The addition of chloramphenicol instantaneously markedly decreased the degradation rate, whereas in the presence of penicillin the degradation proceeded at the beginning at a rate comparable with that in the control and decreased only after a certain time interval. The cell wall degradation was considerably or completely stopped during the stationary phase of growth. In sporogenic strains ofBacillus megaterium andBacillus cereus the release of mature spores was associated with a new wave of the wall degradation, during which the wall of the sporangial cell was completely digested to TCA-soluble fragments. Free spores contained practically no mucopeptide component (cortex or spore wall) originating from the wall of the vegetative cell. A possible existence of a stable fraction of the cell wall not subject to turnover was investigated by measuring the³H/¹⁴C ratio in cells labelled simultaneously with³H (or¹⁴C)-diaminopimelic acid and¹⁴C (or³H)-leucine. The ratio changed during five generations, remaining constant later. This indicates that a certain portion of murein could be stable. The murein degradation during growth was not associated with secretion or release of a significant quantity of autolytic enzymes into the medium. The wall was apparently attacked from the inside. On the other hand, the release of the spore was accompanied by an increasing autolytic activity in the medium. This latter activity reached values corresponding to 3–8 μg lysozyme/ml. The results published here were presented at the 2nd Harden Conference “Cell walls and cell membranes”, Wye, Kent, England in September 1970.     

La cuticule proctodéale des insectes

Résumé La formation des divers types de cuticule rectale a été suivie au cours de la mue chezKalotermes flavicollis (Isoptera). Dans l'épithélium rectal, l'épicuticule externe est formée de couches alternativement sombres et claires, comme dans les autres types de cuticule; l'épicuticule interne présente d'abord une fine lamellation de sa région superficielle, lamellation qui disparaît ensuite. Sur les papilles rectales, l'épicuticule externe a d'abord le même aspect, mais ensuite des différences apparaissent dans l'évolution des différentes couches; ces différences sont encore plus accentuées dans les dépressions épicuticulaires, où les couches superficielles de l'épicuticule externe disparaissent. Sur le cadre bordant les papilles, le dépôt de l'épicuticule externe est peu différent de ce qu'on observe sur l'épithelium rectal; l'épicuticule interne, très mince, présente là aussi une lamellation temporaire; le reste de la cuticule acquiert d'emblée la structure homogène observée pendant l'intermue. Dans tous les cas, la sécrétion de la cuticule (y compris la sous-cuticule) est terminée au moment de l'exuviation. Les modifications des cellules sont brièvement décrites; les cellules des papilles rectales subissent une dédifférenciation complète de leur surface apicale, mais, sur les faces latérales, les associations des mitochondries avec les replis des membranes plasmiques subsistent en grande partie.

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Proctodeal cuticle of insectsII. Formation during the molt

Summary The formation of the different kinds of rectal cuticle has been followed during the molt inKalotermes flavicollis (Isoptera).In the rectal epithelium, the outer epicuticle consists of alternating dark and light layers, as previously described in other types of cuticle; the inner epicuticle first exhibits in its superficial part a thin multilayered pattern, which later disappears.In the rectal papillae, the outer epicuticle has primarily the same appearance, but the evolution of the various layers is somewhat different; even more pronounced differences occur in the epicuticular depressions where the more superficial layers of the outer epicuticle disappear.In the border of the rectal papillae, the outer epicuticle is laid down according nearly the same way as in the rectal epithelium; the temporary multilayered pattern of the very thin inner epicuticle also may be observed; the underlying part of the cuticle, as soon as it is formed, shows the homogeneous appearance observed during the intermolt.In all the cases, the secretion of the cuticle (sub-cuticle included) is achieved when the ecdysis occurs.The modifications affecting the cells are briefly described; the apical surface of the rectal papillae cells undergoes a complete dedifferentiation, but, on the lateral faces, the associations of mitochondria with plasma membrane interdigitations for a large part remain unchanged.

     

A cinefluorographic study of mandibular movement during feeding in the rat (Rattus norvegicus)

The anatomy of the masticatory apparatus, and particularly of the mandibular joints, has led to the view that mandibular movement in the Rodentia is predominantly propalinal, or forwards and backwards in direction. As part of an investigation into the mechanism of function of the mandibular joints in these animals, the feeding behaviour of "August" strain and "Wistar" rats was examined by cinephotography and cinefluorography. The rats were trained to feed on barium sulphate impregnated biscuit and animal cake and to drink radio-opaque liquids. Cinefluorographic recordings of ingestion, mastication, deglutition and of drinking were taken in both the lateral and dorso-ventral projections.
Analysis of the recordings has shown a fundamental separation of ingestive and masticatory activity in the rat, which can be attributed to the morphology of the jaws and particularly to the disparity in the lengths of the mandibular and maxillary diastemas. To bring the incisor teeth into occlusion for ingestion, the mandible is brought forward through the rest position and the condyle into articulation with the anterior part of the fossa. In mastication the condyle is moved backwards to bring the molar teeth into occlusion and the condyle into articulation with the posterior articular facet on the fossa. Once the mandible has been moved into the appropriate position for either ingestion or mastication and deglutition, the movements involved in the separation or chewing of the food are cyclical with combined horizontal and transverse movements as well as the fundamental vertical movement acting to open and close the mouth. The basic movement of ingestion carries the mandibular incisors upwards and forwards across the lingual surfaces of the maxillary incisors, so separating the bite. The grinding stroke of mastication is a horizontal movement carrying the mandibular molars anteriorly across the maxillary.