Light Microscopic Observations of Infraciliature and Morphogenesis in Six Species of Rumen Ostracodinium Ciliates

Infraciliature and morphogenesis of six rumen ciliates, Ostracodinium mammosum, O. munham, O. dilobum, O. rugoloricatum, O. iwawoi, and O. tiete are described from pyridinated silver carbonate-impregnated specimens. These six Ostracodinium have a similar polybrachykinety arrangement, distinct from that of other ophryoscolecid ciliates and intermediate between those of O. gracile and 0. damaliscus. Buccal infraciliature is composed of three polybrachykineties, a kinety loop, and paralabial kineties. Small dorso-adoral polybrachykinety, slender vestibular polybrachykinety, and kinety loop are characteristic. Dorsal infraciliature consists of the dorsal polybrachykinety that extends laterally along the dorsal side of the body. Morphogenesis is different from that of O. gracile, because the right end of ventral primordium extends dorsally to grow into a right primordium without separation.     

Effects of Organic Matter on Solubilities and Crystal Form of Carbonates

The results of a study of the role of organic compounds in theformation of carlxmate crystals in marine biological systemsare reported. In an increasing concentration of certain organiccompounds which complex calcium ions, the proportion of aragonitedecreases and that of calcite increases. In increasing concentrationsof magnesium ions the proportion of aragonite increases andthat of calcite and vaterite decreases. When the influence oforganic compounds is greater or smaller than that of magnesiumions, only calcite or only aragonite is formed, respectively.Organic compounds forming a strong complex with calcium ionscause the formation of magnesium-rich calcite, and with an increasein temperature and the concentration of magnesium ions, themagnesium carbonate content of precipitated magnesian calciteincreases. When the influence of organic compounds is almostequivalent to that of magnesium ions, in increasing or decreasingtemperatures, the proportion of calcite decreases or increases,respectively, and the proportion of aragonite increases or decreases,respectively. The concentration of magnesium ions in the bodyfluids of marine calcareous organisms seems to differ littlefrom that of other organisms, and seems to be similar to thatof sea water. Only the presence of certain organic compoundsbrings about the formation of the carbonate crystals observedin marine biological systems. The very important role of organicmatter in the formation of crystals found in skeletal carbonatesis emphasized.     

Melanoma Antigen and Transforming Gene

We summarize our recent studies on the analysis of melanoma antigen and the melanoma gene recently cloned. The melanoma antigen analyzed by syngeneic monoclonal antibodies is composed of a complex of GM3 ganglioside and protein molecules. The epitope recognized by antimelanoma cytotoxic T lymphocytes seemed to be the combinatorial determinants of GM3 and proteins, whereas the epitope for the suppressor T cells was found to be solely GM3 (NeuAc). The genomic DNA controlling the melanoma antigen was recently isolated and was found to possess transforming activity. The structure of this transforming gene is discussed based on the sequence data of the corresponding cDNA clone.     

Pattern and Time Course of Cleavages in Early Development of the Ovoviviparous Pond Snail, Sinotaia quadratus historica

The pattern and time course of cleavage during early development of the ovoviviparous pond snail, Sinotaia quadratus historica , in in vitro culture were investigated. The fertilized egg, 25–30 μm in diameter, underwent cleavage by repeated constriction and compaction as in blastocyst formation in mammalian embryos. The cleavage was slightly unequal and dextrally spiral, although a slight time lag in cleavages of blastomeres was observed after the 2nd cleavage. A small polar lobe was formed at the 1st cleavage, but not at the 2nd cleavage. Each cleavage proceeded very slowly under the experimental conditions, the 1st, 2nd, 3rd and 4th cleavages taking 22 hr or more, 9 hr and 10 hr, respectively. The cleavage pattern in in vitro cultures observed by light microscopy was confirmed by scanning electron microscopy.     

Studies on nitrogen metabolism in tobacco plants IX. Effect of various compounds on proline biosynthesis in the green leaves

In order to obtain information on the correlation between thebiosynthesis of proline from glutamate and photosynthesis ingreen leaves, the effects of various substances on proline formationfrom ¹⁴C-glutamate have been investigated using tobacco leafdisks in the light. Inhibitors of oxygen evolution in photosynthesis,such as CMU, strongly inhibited the proline formation. The inhibitioncould not be reversed by the addition of reduced NADP, ascorbateplus 2,6-dichlorophenol-indophenol or ATP. Uncouplers or inhibitorsof photophosphorylation such as DNP, arsenate, chlorpromazineand octyl guanidine suppressed the formation of proline fromglutamate. In old leaves, the addition of ADP or ATP markedlyaccelerated proline formation, while neither of these compoundswas effective in young leaves. It was inferred that the reductionof glutamate to ¹-pyrroline-5-carboxylate in green leaves isclosely associated with noncyclic photophosphorylation. (Received August 17, 1967; )     

ACQUISITION OF COMPETENCE FOR CULMINATION DURING FINGER FORMATION IN DICTYOSTELIUM DISCOIDEUM

Finger-like structures of the cellular slime mold, Dictyostelium discoideum , were disrupted with a fine needle and the resulting cell masses were allowed to develop. When complete fingers formed under overhead lighting were disrupted, the cell masses rapidly became transformed into fruiting bodies. Development of similar cell masses from fingers reared in the dark was affected by the lighting conditions after disruption: under overhead lighting the cell masses rapidly culminated; under unilateral lighting, they formed fingers again and then migrating slugs.
In contrast, the cell masses from mounds with tips formed fingers regardless of the lighting conditions.
It is concluded from these findings that the cells become competent for culmination during finger formation under overhead lighting.     

Crown Spread Patterns for Five Deciduous Broad-leaved Woody Species: Ecological Significance of the Retention Patterns of Larger Branches

Patterns of crown spread and branch retention of two shade-intolerantspecies (Betula platyphyllaandB. maximowicziana) were comparedwith three more tolerant species (Quercus mongolica,Acer sieboldianumandMagnoliaobovata). Branching height (height of the lowest living branch)rose more rapidly with age for the twoBetulaspecies than forthe shade tolerant species. Branching heights ofA. sieboldianumandM.obovatawere similar, irrespective of tree height and age, andlarger trees tended to produce wider crowns than theBetulaspecieswhen trees of similar height were compared. In all species,the branch basal area (cross-sectional area of a branch at itsbase) and the leaf area per branch generally increased as thebranch position on a stem became lower. Therefore, retaininglarger branches contributed significantly to the support ofa larger leaf area per tree. The number of larger branches (branchbasal area >80 cm²) for bothBetulaspecies was significantlysmaller than that of the shade tolerant species. The branchretention pattern ofBetulaspecies was probably a consequenceof intolerance of the leaves to shade. The decline ofBetulaspecieswith forest succession is likely to occur through their inabilityto retain branches with a large base area in closed forests.Copyright1997 Annals of Botany Company Shade tolerance; crown spread; branch retention; branch size; broad-leaved woody species; leaf area index per tree