ALBERT

Notes: Abstract The elemental composition and spectroscopic properties of dissolved fulvic acids isolated from different sampling media (topsoil, ground and surface water) of a natural fen area (high portion of organic soils) were examined to reveal the effects of land use history. These effects need to be known if dissolved humic substances are to be a major factor in identifying the impact of present and future changes in land use. Dissolved fulvic acids (topsoil, groundwater) from highly degraded peatlands (due to a long-term agricultural use) exhibit lower C/N ratios, higher absorption in the UV spectra, and higher absorption at 1,620 cm−1 in the FTIR spectra compared with fulvic acids from relatively intact peatlands. These properties illustrate that long-term agricultural use with high inputs results in increased aromatic structures and a further humification of dissolved fulvic acids due to very strong peat decomposition compared with relatively intact peatlands. Synchronous fluorescence spectra also indicate the higher level of aromatic structures within fulvic acids isolated from sites with long-term agricultural use (high peat decomposition) compared with a land use history resulting in a lower peat decomposition. The different sources of fulvic acids in surface water (precipitation, runoff, interflow, groundwater) are the main reason for these effects not being detected in fulvic acids isolated from surface water. Short-term changes in land use characterized by a transition from crop farming to an unimproved grassland were found not to affect the spectroscopic properties of dissolved fulvic acids. A humification index deduced from the synchronous fluorescence spectra is proposed. We have strong evidence that dissolved humic substances indicate changes in the environmental conditions (both anthropogenic and natural) of wetlands with a high proportion of organic soils.

Notes: Abstract The elemental composition and spectroscopic properties of dissolved fulvic acids isolated from different sampling media (topsoil, ground and surface water) of a natural fen area (high portion of organic soils) were examined to reveal the effects of land use history. These effects need to be known if dissolved humic substances are to be a major factor in identifying the impact of present and future changes in land use. Dissolved fulvic acids (topsoil, groundwater) from highly degraded peatlands (due to a long-term agricultural use) exhibit lower C/N ratios, higher absorption in the UV spectra, and higher absorption at 1,620 cm−1 in the FTIR spectra compared with fulvic acids from relatively intact peatlands. These properties illustrate that long-term agricultural use with high inputs results in increased aromatic structures and a further humification of dissolved fulvic acids due to very strong peat decomposition compared with relatively intact peatlands. Synchronous fluorescence spectra also indicate the higher level of aromatic structures within fulvic acids isolated from sites with long-term agricultural use (high peat decomposition) compared with a land use history resulting in a lower peat decomposition. The different sources of fulvic acids in surface water (precipitation, runoff, interflow, groundwater) are the main reason for these effects not being detected in fulvic acids isolated from surface water. Short-term changes in land use characterized by a transition from crop farming to an unimproved grassland were found not to affect the spectroscopic properties of dissolved fulvic acids. A humification index deduced from the synchronous fluorescence spectra is proposed. We have strong evidence that dissolved humic substances indicate changes in the environmental conditions (both anthropogenic and natural) of wetlands with a high proportion of organic soils.

Notes: Abstract Neutral complex-type N-glycans of the envelope glycoprotein 120 of HIV-2, propagated in different host cells, display cell-type specific variations. In order to identify typical structural elements, glycans were analysed by gel filtration, by enzymic sequencing and, in part, by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The characteristic substituents of di- tri- and tetraantennary carbohydrate units thus observed include N-acetyllactosamine repeats, bisecting N-acetylglucosamine and fucose linked to the chitobiose core as well as to N-acetyllactosamine antennae. Each glycoprotein preparation displayed a characteristic set of glycoforms. Abbreviations: endo H, endo-β-N-acetylglucosaminidase H; E-PHA, Phaseolus vulgaris agglutinin E4; GlcNAcOH, N-acetyl-glucosaminitol; gp120/HUT78(MOLT4/Mφ/PBL/U937), external envelope glycoprotein 120 of HIV-2, strain D194, propagated in HUT78 (MOLT4, Mφ, PBL, U937) cells; gu, glucose units; HPAEC, high-pH anion-exchange chromatography; MALDI-TOF-MS, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; Mφ, human monocytes/macrophages; PBL, human peripheral blood lymphocytes; PNGase F, peptide-N4-(N-acetyl-β-glucosaminyl)asparagine amidase F

Notes: Abstract. Multimedia streams such as audio and video impose tight temporal constraints for their presentation. Often, related multimedia streams, such as audio and video, must be presented in a synchronized way. We introduce a novel scheme to ensure the continuous and synchronous delivery of distributed stored multimedia streams across a communications network. We propose a new protocol for synchronized playback and compute the buffer required to achieve both, the continuity within a single substream and the synchronization between related substreams. The scheme is very general and does not require synchronized clocks. Using a resynchronization protocol based on buffer level control, the scheme is able to cope with server drop-outs and clock drift. The synchronization scheme has been implemented and the paper concludes with our experimental results.

Notes: Summary The first spermatocyte division has been investigated in Rhabdophaga batatas Walsh and Wachtliella persicariae L. It was shown that the course of this division cannot be described as mitosis, either “unipolar” or “modified bipolar”. Its essential features are: complete absence of pairing and the segregation of the chromosomes into two groups composed of 4 and 30-odd chromosomes. The segregation is accomplished by a peculiar expulsion of the group of 4 chromosomes from the main nucleus followed by an unequal cytokinesis. The spindle is absent and the nuclear membrane remains present during the entire course of the division. The second spermatocyte division occurs only in the smaller cell, which contains 4 chromosomes and bears all features of normal mitosis. For the description of the course of the first spermatocyte division and chromosome distribution, which occurs in this division, the terms “segregating division” and “monocentric configuration” were proposed. The available descriptions of the first spermatocyte division in other species of Cecidomyiidae have been analyzed. The pattern of this division in all so far investigated cecidomyiid species is very uniform and the terms “unipolar” or “modified bipolar” mitoses are here also inadequate. The cases were discussed in which the peculiar chromosome arrangements arise merely as a result of positive or negative interrelations between the centriole and the chromosome parts. With this as background, the monocentric configurations in Cecidomyiidae were explained in terms of an attraction between the centriole and centromeres, operating in one group, and a repulsion between the centriole and the chromosome ends acting in the second. The other so-called unipolar mitoses have been analyzed. It was shown that under this term at least three intrinsically different configurations have been described. For the cases of Sciara, Micromalthus debilis and Cecidomyiidae, the common denominator can be found: the chromosome movements in Sciara and M. debilis can also be explained as set forth above for Cecidomyiidae, i.e. in terms of two kinds of forces operating between the centriole and the chromosomes. The several spindle fibers present in Sciara and Micromalthus do not seem to be crucial for the chromosome movements.

Notes: Summary The structure and behavior of XY bivalent in mice is discussed. The view that XY bivalent in pachytene is embedded within the sex vesicle was fully confirmed. X and Y are paired end-to-end by a nonchiasmatic connection, which is established already in pachytene and persists until first meiotic metaphase. The pachytene complement in mice consists of 19 rod-shaped autosomal bivalents and the XY bivalent embedded within the sex vesicle. A satisfactory identification of individual autosomes in male pachytene has not been found possible.

Notes: Summary The extensive genetical analysis of the T-locus in mice, carried out by Dunn and his co-workers, has revealed that the breeding pattern of t-alleles is very peculiar. The complexity of the T-locus indicates that some structural rearrangements are involved here. The purpose of the present work was to gain some informations on the structure of chromosomes in which t-alleles are present. 2. The course of spermatogenesis in the lines of mice of the following genotypes was investigated: +/+; T/+; T/t n — namely T/t 0, T/t12, T/tw1, T/tw6, T/tw18; tn/tx — namely t 0/t12, t0/tw18, t12/tw18, tw1/t12, tw1/t0, tw1/tw6, tw1/tw18, and in heterozygotes for translocations T138 and T190, both involving the fragment of linkage group IX in which some t-alleles are present and used as markers. 3. The alleles T and t w1 are not connected with structural rearrangements, as far as detectable by the methods used. The alleles t 0, tw6 and t w18 are interstitial deficiencies involving different chromosomal regions. The most complete data were obtained for t 0: in T/t 0 heterozygotes a loop corresponding to a big interstitial deficiency was present, in all t 0/tn compounds the aberrant structure of one of the bivalents indicated that an interstitial deficiency is here involved. By analysis of translocation T190 the deficiency loop is localized in the chromosome representing linkage group IX. The identification of t w6 as a small interstitial deficiency is based on the analysis of T/t w6 heterozygotes and its localization in linkage group IX on the presence of this deficiency in translocation T138. The description of tw18 as a small interstitial deficiency stems from the analysis of T/tw18 and t 0/tw18, the localization in linkage group IX is shown by its presence in t 0/tw18 in the same bivalent as t 0. The evidence obtained for t 12 indicates that it is either a big terminal deficiency or a small interstitial one inducing constant asynapsis in adjacent terminal segments of the bivalent. 4. The reasons why loops encountered in genotypes involving t 0, tw6 and t w18 are considered as deficiencies and not as duplications are based on available embryological and genetical data. The possible connections between the mode of action of the investigated t-alleles as embryonic lethals and the cytological results on their structure and localization are discussed. 5. Most of the lethal t-alleles suppress crossing-over in the region T-tf. Factors reducing the frequency of recombination in other organisms are discussed in comparison. It is concluded that the pattern of aberation in meiotic behavior of the bivalent carrying t-alleles is for almost each of the studied alleles rather specific and does not permit for suggesting any general mechanism which could account for the action of investigated lethal t-alleles as crossing-over suppressors. 6. A diagram of the presumable localisation of genetical factors in linkage group IX is presented. It is concluded that the so-called T-locus occupies the main part of the long arm of the chromosome corresponding to linkage group IX and that the investigated t-alleles are not unilocal neither with the gene T nor each with other, but scattered along the chromosome. 7. The possible modes of the origin of new t-alleles are discussed, and the hypothesis is advanced that this event might be connected with mistakes of replication of the strand on which a new t-allele arises.

Notes: Zusammenfassung In der vorliegenden Arbeit wurde die Wirkung des Ultraschalls auf die Tryptophanase in Escherichia coli untersucht. Es konnte nachgewiesen werden, daß Ultraschall das Tryptophanase-Protein angreift, während das Coenzym Pyridoxalphosphat nicht verändert wird. Weiterhin wurde die Veränderung des Pyridoxalphosphats durch Ultraschall in vitro festgestellt.

Notes: Zusammenfassung Um zu klären, ob der Tod von lebenden Zellen nach Röntgenbestrahlung auf eine Zerstörung des in der Zelle vorhandenen Pyridoxalphosphats und damit auf eine Blockierung der pyridoxalabhängigen Enzyme zurückzuführen ist, wurde in bestrahlten und unbestrahlten Escherichia coli der Pyridoxalphosphat-Gehalt bestimmt. Die Untersuchung wurde an ruhenden und wachsenden Zellen durchgeführt. Durch Bestrahlung mit 10,40 und 80 kr wird der Pyridoxalphosphat-Gehalt der Zelle nicht verändert. Alle Kulturen begannen zur gleichen Zeit am Ende der log-Phase des Wachstums mit der Neubildung von Pyridoxalphosphat.