Efficient separation of subfossil Chironomidae from lake sediments

Electron transport system (ETS) activity, CO₂ evolution, O₂ consumption, N₂-fixation (C₂H₂ reduction) and methanogenesis were appropriately measured in aerobic and anaerobically incubated sediment at 4, 10 and 20 ° C to better characterize these activities under different incubation conditions. ETS activity was always higher in the aerobically incubated sediment at all three incubation temperatures, whereas (C₂H₂ reduction was always greater in the anaerobic sediment. Carbon dioxide evolution was detected only in the aerobic sediment at 10 and 20 ° C but not at 4 ° C. Methane evolution in anaerobic sediment increased gradually with an increase in the incubation temperature.     

An isomer of xanthanol from Xanthium orientale

The aerial parts of Xanthium orientale afforded an isomer of xanthanol.     

Cell Arrangement in Coenobia of Pediastrum

An account is given of the arrangement of cells in the discoidcoenobia of Pediastrum boryanum. Cells are in concentric circlesaround a core of 1, 2, or rarely 3 individuals. In 8-celledcoenobia the arrangement is 2+6; in 16-celled coenobia 1+5+10is most usual; in 32-celled coenobia 1+6+10+15 is the commonestpattern. In 64-celled coenobia the central core appears to be2 (or 3) cells with a pattern such as 2+8+13+19+22. The patternsdeveloped are shown to be more consistent with a close huddlingof zoospores into a symmetrical plate, rather than constrictionby an external circle.     

Delphinium orientale Gay

Ohne ZusammenfassungWeitere Mittheilungen, auch von anderer Seite, dürften noch zu erwarten sein.     

Recovery from acidification in boreal lakes inferred from macroinvertebrates and subfossil chironomids

Acidification of waters and soils caused by emissions and the long-range transport of air pollutants has been a serious worldwide problem during the last decades. The extent of the acidification problem in Finnish acid-sensitive forest lakes was examined in the Acidification Research Project (HAPRO) in the mid-1980s. The recent decline in the emissions of air pollutants has resulted in the chemical recovery of watersheds in many regions, and the present work on the recovery processes in acidified Finnish headwater lakes (REPRO) was launched to examine whether the chemical recovery has already been accompanied by biological recovery. The patterns of recovery were studied by re-sampling littoral macrozoobenthos in a subset of the previously sampled HAPRO lakes. Paleolimnological samples were taken in order to assess the possible dependence of lacustrine chironomid communities on the changing degree of acidification. Acid sensitive and moderately acid sensitive benthic species revealed slight recovery in the formerly most acidic (pH 5.5) but recently recovered lakes. The most significant factors affecting the response of benthic communities were increased mean lake pH and decreased labile aluminium concentration. Paleolimnological chironomid analysis revealed a slight response along the pH gradient, but also significant structural similarity between the present and pristine chironomid assemblages. This implies that no major changes in chironomid communities of these acidic lakes have occurred during the past centuries. The alternative future trends and threats to biological recovery in small headwater lakes are discussed.     

Thalictricoside, a new phenolic compound from Thalictrum orientale

From the underground parts of Thalictrum orientale Boiss., a new phenolic compound 1 was isolated in addition to one known cyanoglycoside, lithospermoside (2). For the structure elucidation of all compounds, 1D- and 2D-NMR techniques (DEPT, COSY, HMBC, HSQC) and MS (HR-MALDI) were used. The structure of the new compound was established as 2-(4'-hydroxyphenyl)-nitroethane-4'-O-[beta-xylopyranosyl-(1 --> 6)-beta-glucopyranoside] (1).     

The subfossil monkey femur and subfossil monkey tibia of the Antilles: A review

The proximal portion of a subfossil monkey femur found in a Jamaican cave shares all the femoral characters of a mature male Cebus apella.The fragment alone, however, does not prove conspecificity. The Jamaican femur is also of a size that could belong to the extinct Xenothrix mcgregoriof the same island. In contrast, the distal portion of a monkey tibia recovered from a kitchen midden in the Dominican Republic cannot be identified with that of any known living platyrrhine or catarrhine monkey. Geological age, geographic locality, and size of fragment point to probable alignment of the tibia with the recently extinct cebid Saimiri bernensis.Although no conclusive identifications are made, the distinctive characters of the two limb bones are described on the basis of comparisons with femurs and tibias representing all genera of living platyrrhines, most genera of catarrhine monkeys, and some strepsirhines.     

NADH Oxidation by Mitochondria from the Thermogenic Plant Arum orientale

The enzyme content of the mitochondrial respiratory chain was investigated in the heat-producing plant Arum orientale. It is shown that mitochondria isolated from thermogenic tissues of this plant (with respect to non-thermogenic tissues of A. orientale or to Zea mays) demonstrate significantly elevated levels of activities of two non-coupled NADH dehydrogenases oxidizing intramitochondrial and cytoplasmic NADH pools. It is postulated that operation of a completely non-coupled respiratory chain consisting of non-coupled NADH:quinone oxidoreductases and cyanide-resistant alternative quinol-oxidase is the main mechanism of heat production in thermogenic plants.     

Size, space, and adaptation in some subfossil lemurs from Madagascar

We examine several explanations for the geographic pattern of body size variation exhibited by the subfossil lemur Archaeolemur. Part and partial correlation analysis and multiple regression analysis are applied in a stepwise, hierarchical fashion to help to determine variable interdependencies. Variance in site means for body size is best explained by the richness of the plant community and by several correlated climatic variables (bioclimatic zone and mean annual rainfall). Body size differentiation in Archaeolemur roughly mirrors patterns observed among many other Malagasy lemur species and subspecies groups. This consistency alone suggests that common ecological factors have strongly affected size differentiation in lemurs, most probably (as suggested by our correlation analyses) by uniformly influencing the productivity of their niches. Smaller individuals tend to inhabit arid regions, and larger individuals tend to inhabit wetter regions. The interplay between selective differentiation and allopatric speciation appears to have yielded the concordant pattern of size variation observed in Malagasy lemurs.     

Dental microwear texture analysis of two families of subfossil lemurs from Madagascar

This study employs dental microwear texture analysis to reconstruct the diets of two families of subfossil lemurs from Madagascar, the archaeolemurids and megaladapids. This technique is based on three-dimensional surface measurements utilizing a white-light confocal profiler and scale-sensitive fractal analysis. Data were recorded for six texture variables previously used successfully to distinguish between living primates with known dietary differences. Statistical analyses revealed that the archaeolemurids and megaladapids have overlapping microwear texture signatures, suggesting that the two families occasionally depended on resources with similar mechanical properties. Even so, moderate variation in most attributes is evident, and results suggest potential differences in the foods consumed by the two families. The microwear pattern for the megaladapids indicates a preference for tougher foods, such as many leaves, while that of the archaeolemurids is consistent with the consumption of harder foods. The results also indicate some intraspecific differences among taxa within each family. This evidence suggests that the archaeolemurids and megaladapids, like many living primates, likely consumed a variety of food types.     

Pattern formation of the coenobial algae Pediastrum biwae Negoro

It is suggested that flat colony patterns of the coenobial green algae Pediastrum biwae Negoro can be determined only by some properties of the zoospores without any other control system as a whole. These suggestions are made through observations of colony patterns and colony formation during asexual reproduction and digital electronic computer simulation. The zoospore can be regarded as a sphere which has two C-sites (presumptive sites for connection) and one H-site (presumptive site for horn formation) on its equator. This sphere swims rapidly at random in a transparent vesicle and undergoes a series of changes in its properties: (i) the regions along the equator might come to have a slight affinity for each other, which could cause the arrangement of the zoospores into a plane; (ii) the two C-sites might become connection sites and the zoospores, therefore, might form strings, leading to the characteristic pattern of the adult colony (e.g. a few concentric circular strings, a spiral string and so on); and finally, (iii) the H-site of the zoospore determines whether it grows to a horn or not, i.e. the zoospore grows into a horn cell or a triangular cell according to the absence or presence of other zoospores which prevent its growth.     

Control of palmelloid formation in the green alga Pediastrum

Pediastrum tetras, normally a non-motile colony of eight cells,aggregates into large masses of up to 1500 µ in diameterwhen grown in certain nutrient media. These masses ("palmelloids")can be prevented from forming or can be dissociated into separatecolonies by either high pH or ferric ions. The average particlesize is inversely proportional to the concentration of Fe⁺⁺⁺between zero and about 300 µM. Iron chelators such asEDDHA have no effect. These data are discussed in comparisonwith the control of palmelloid formation in other genera. (Received February 12, 1972; )     

Mitosis, Cytokinesis and Colony Formation in Pediastrum boryanum

Uninucleate cells of Pediastrum become multinucleate by a seriesof synchronous mitoses. Mitotic nuclei are enclosed by a perinuclearenvelope of endoplasmic reticulum. Cytoplasmic cleavage of themultinucleate cells leads to the production of uninucleate,biflagellate zoospores (zooids) which are subsequently releasedinto a lenticular vesicle through a rupture in the outer layerof the parental cell wall. Within the vesicle, presumably derivedfrom part of the inner layer of parental wall, the zooids swarmactively before aggregating in a planar array. Bands of microtubulesunderlie the plasmalemma of the zooids which, when the zooidsaggregate, are usually coplanar with the newly formed colony.The role of microtubules in patterned colony formation and inthe development of the characteristic horns on peripheral cellsof colonies of Pediastrum is discussed.     

Modified subfossil aye-aye incisors from southwestern Madagascar: species allocation and paleoecological significance

Two of the three drilled aye-aye incisors collected in 1901 by Grandidier at the subfossil site of Lamboharana were recently rediscovered in uncatalogued collections of the Institut de Paléontologie in Paris. These teeth are not much wider or thicker than those of the extant aye-aye (Daubentonia madagascariensis), but their arc of curvature is noticeably greater. These facts indicate that the teeth probably belong to D. robusta, a large extinct aye-aye whose dentition is otherwise unknown. No other remains referable to Daubentonia have been reported from Lamboharana, although D. robusta is known from other localities in the southwest. The presence of Daubentonia in southern Madagascar does not demonstrate that this region was markedly more humid or densely forested in the recent past. It remains to be established whether the extinction of D. robusta throughout its range in southern Madagascar, and local disappearance of D. madagascariensis everywhere but in the eastern forest biotope, is due to late Holocene climatic change, to anthropogenic effects, or both factors combined.     

Division of Chloroplasts in a Green Alga, Pediastrum duplex

The division of chloroplasts in a green alga, Pediastrum duplex,was studied by electron microscopy. Cells were treated for observationwith the freeze-substitution method. Fibrils, or fibrous belts,which we had observed previously at the dividing constrictionsof chloroplasts in Trebouxia potteri were not visible in Pediastrum,even though the method of preparation was the same for bothsets of samples. Microtubules (MTs) and the septum seem notto participate directly in the division of the single chloroplastin Pediastrum cells. Many thin fibrils, 7–20 nm in diameter,attached to, or protruding from, the surface of the dividingconstriction were seen. These fibres were less densely distributedat the constrictions of non-dividing chloroplasts. It is suggestedthat these fibrils are involved in the divison of chloroplastsin Pediastrum duplex. Cell wall, chloroplast division, freeze-substitution, intermediate fibres, Pediastrum duplex, transmission electron microscopy     

Alisolide, alisols O and P from the rhizome of Alisma orientale

A nor-protostane, alisolide (1), a rearranged protostane, alisol O (2), and a 2,3-seco-protostane triterpene, alisol P (3), were isolated from the rhizomes of Alisma orientale, along with eight known protostane triterpenes. The structures were elucidated to be (17S)-3,11-dioxo-23-nor-protost-12-en-23(17)-olide, 3-oxo-11beta,23-dihydroxy-24,24-dimethyl-26,27-dinorprotost-13(17)-en-25-oic acid, and (20R,23S,24R)-23,24,25-trihydroxy-2,3-seco-protost-13(17)-en-3-oic acid 2,11beta-lactone, respectively, by interpretation of spectroscopic data.     

泽泻染色体的核型分析

对泽泻体细胞染色体计数,并对其核型进行分析,结果表明：泽泻的染色体数目为2n=14;核型公式为2n=2x=14=10m 4T,染色体相对长度组成为2n=14=2L 6M2 2M1 4S,属于2B型。全组染色体总长40．15μm,长臂总长为25．14μm,核型不对称系数为62.62％。染色体总体积为104．26μm^3。