A turbidimetric method for the screening of amylase-producing mutants of Aspergillus niger

Summary The method is based on the assumption that extracellular amylase, which is produced by strains ofAspergillus niger in liquid culture, hydrolyses the starch in the media and brings about a corresponding decrease in the turbidity of the media. Mutant strains which produced different quantities of amylase exhibited different degrees of decrease in turbidity of the media. The results showed that a greater degree of decrease in turbidity was observed for a higher quantity of amylase produced.     

A method for automatic recording of serum lysozyme activity with the fragiligraph

Summary A quick and simple method for the estimation of lysozyme activity using the Fragiligraph, was described. Diminution of turbidity in a suspension ofMicrococcus lysodeikticus produced by the addition of standard lysozyme (hen egg white) or serum sample, was continuously recorded for 5 min by the Fragiligraph. The normal mean serum lysozyme activity value obtained by this method is 6,80 g/ml±1.85.We gratefully acknowledge the excellent technical assistence of MissM. Touma.     

Elektronenmikroskopische Aufnahmen von Pollenschläuchen

Summary Electron micrographs were made of the cellulose part of the cell walls of pollen tubes ofPetunia hybrida, grown in selfed self-sterile plants and on agar plates. In sterile plants the tubes showed denser membranes but the orientation of the cellulose strands is the same as in cells germinated on agar.     

Sterility in tsetse flies (Glossina morsitans Westwood) caused by loss of symbionts

Summary Tsetse flies fed on blood containing oxytetracycline, sulphaquinoxaline or lysozyme do not reproduce. It could be proved that primarily the symbionts in flies are damaged, which secondarily leads to sterility.I thank Dr.A. M. Jordan, Tsetse Research Laboratory at Bristol, for providing me with pupae ofG. morsitans, Dr.H. Wetzel, International Atomic Energy Authority, Vienna, for providing antibiotictreated flies and the Gesellschaft für Strahlen und Umweltforschung, München, for financial support.     

Nuclear fusion and irregular cytokinesis in binucleate and tetraploid cells ofVicia faba after caffeine treatment

Summary By means of 3 h treatment with 0.2% caffeine solution, binucleate and tetraploid cells were obtained in the lateral root meristem ofVicia faba. During recovery changing rates of fused interphases were noticed. Cell walls were formed in the equatiorial plane of the preceeding division of binucleate and tetraploid cells at interphase and in the course of bimitosis or 4n-mitosis at prophase or metaphase; during bitelophase a constriction of the fused nuclei could be seen. The conclusion is that the basic requirements of cytokinesis are not affected by caffeine.     

Heterozygous effects on cell yield and generation time inSaccharomyces cerevisiae

Summary The data obtained analyzing generation time, cell yield and their variability in different culture media in diploid strains ofSaccharomyces cerevisiae demonstrate the existence of a biochemically determined heterotic effect, that could be of some relevance for the study of yeast population genetics, as well as for the improvement of microbial fermentation processes.     

Different effects of D-glucose anomers for respiration of bacterial germinated spores

Summary Effects of - or -D-glucose on the respiration of germinated spores (only germinated spores not including swollen spores and elongated spores) ofBacillus subtilis andB. megaterium were studied. In our conditions, net amount of oxygen consumed by 10¹⁰ germinated spores ofB. subtilis per min after addition of - or -D-glucose was 1.6 g or 6.6 g (/=4.13), while that byB. megaterium was 4.5 g or 6.8 g (/=1.51), respectively. However, the net amounts of oxygen consumed by 10¹⁰ vegetative cells per min after addition of - or -D-glucose were identical, forB. subtilis in both cases 443.0 g and forB. megaterium in both cases 604.4 g.     

Host cell reactivation capacity of different strains ofE. coli B resistant or sensitive to ozone

Summary Host cell reactivation capacity for ozonated or irradiated phage was determined for different strains ofE. coli either more sensitive or resistant to ozone than the wild type strain. The results suggest that theozr gene product could be involved in the same repair pathway for ozone-induced lesions on DNA as thepolA gene. The possible involment of a specific endonuclease for these lesions is also considered.This research was sponsored by the National Sciences and Engineering Research Council of Canada. P.L.H. acknowledges a postgraduate scholarship from the NSERC of Canada.     

Regeneration of plants from mesophyll protoplasts ofAtropa belladonna

Summary Isolated leaf mesophyll protoplasts ofAtropa belladonna when cultured in defined liquid culture media regenerate cell walls, divide and form calli. Subsequent induction of shoot and root organogenesis leads to plantlets which grow to maturity after transfer to soil.Acknowledgment. We are indebted to Václav Mandák for skilful technical assistance.     

Urochordates carry multiple genes for goose-type lysozyme and no genes for chicken- or invertebrate-type lysozymes

Genome clones and expressed sequence tags (ESTs) from the ascidian Ciona intestinalis and from the larvacean Oikopleura dioica were analysed for the presence of lysozyme-encoding genes. Two genes were found to potentially code for goose-type lysozymes in Oikopleura, while three or possibly more g-type proteins form the lysozyme complement of C. intestinalis, and at least one of these genes from each species is expressed based on EST data. No genes for chicken- or invertebrate-type lysozymes were found in either urochordate species. Consistent with this finding, extracts of Oikopleura animals possessed hydrolysing activity on bacterial cell walls, and this activity was not inhibited in the presence of a known inhibitor of chicken-type lysozyme. A wide range of isoelectric points for the predicted lysozymes from Ciona (pI 4.4, 6.4 and 9.9) and from Oikopleura (pI 5.0 and 8.0) suggests tissue-specific adaptations as well as specific functional roles of the lysozymes. Comparisons of gene structures, encoded sequences, cysteine residue content and their positions in the proteins indicate that the g-type lysozymes of Ciona intestinalis are more closely related to those of vertebrates than are the g-type lysozymes of Oikopleura. Multiple genes from each species may result from separate and lineage-specific duplications followed by functional specialisation.Received 29 June 2003; received after revision 24 July 2003; accepted 29 July 2003     

The course ofPlasmodium berghei infection in mice latently infected withToxoplasma gondii

Summary The course of infection with 2 different virulent strains ofPlasmodium berghei was investigated in mice latently infected withToxoplasma gondii. When given the highly virulent ANKA strain ofP. berghei all Toxoplasma-infected mice died but the survival time was prolonged. After infection with the less virulent strain K 173 mice could survive the subsequent infection. In these cases levels of parasitemia depended upon the duration of theT. gondii infection. Mice infected for about 6 weeks withT. gondii showed maximum protection. These studies were conducted in the Institut für Medizinische Parasitologie der Universit?t Bonn (D-5300 Bonn, Federal Republic of Germany).     

Effect of hot formamide on gram-positive and gram-negative cell walls

Zusammenfassung Die obere Schicht der Zellwände vonB. megaterium M undB. subtilis wurde mittels Extraktion mit heissem Formamid beseitigt. Zurückbleibende stäbchenförmige, etwa 110 Å dicke Membranen entsprechen offenbar der rigiden Mucopeptid-Basalmembran der Bakterienzellwände     

Incorporation of uridine diphospho-N-acetyl-D-glucosamine in the resting sporangium wall ofSynchytrium endobioticum

Summary The microfibrils that constitute the walls ofSynchytrium endobioticum resting sporangia are laid down at the periphery of developing walls and are packed in discrete orientation. Incorporation of uridine diphospho-N-acetyl-D-glucosamine, a precursor of chitin, is restricted to the periphery of the developing wall of the resting sporangium.     

Antigenic components of germinated spores ofBacillus megaterium

Riassunto Sono stati studiati gli antigeni di forme vegetative, spore quiescenti e germinate diB. megaterium. È. stato possibile individuare che le 3 forme possiedono sia antigeni propri sia antigeni comuni.     

Plant constitutents involved in coating practices among traditional African potters

A phytochemical survey of several plant species used in sub-Saharan Africa for the treatment of pottery, as well as some coating experiments carried out with purified extracts ofBridelia ferruginea stem bark, indicated that procyanidin fractions play a predominant role in the coating properties of the plant extracts. The analysis by high performance gel permeation chromatography of organic compounds isolated from the vessel walls suggested that products deriving from pyrolysis of procyanidins are detectable both in contemporary and older pottery, and their analysis could be useful for archaeological purposes.     

Das Spitzenwachstum der Fasern beiLinum perenne L

Summary In shoots ofLinum perenne apical growth was observed at both ends of the fibres. Their rounded tips, rich in protoplasm, protude into the middle lamellae of adjacent fibres or parenchyma cells. In addition to their apical growth, the fibre walls undergo symplastic growth with the walls of neighbouring cells. The formation of the pointed ends of fully developed fibres is described.     

Endotoxin-like activity inPseudomonas paucimobilis (group IIK biotype 1) andFlavobacterium multivorum (group IIK biotype 2)

Summary 7 strains ofPseudomonas paucimobilis and 7 strains ofFlavobacterium multivorum (formerly groups IIK biotype 1 and biotype 2, respectively) showed endotoxin-like activity in vitro by the limulus amoebocyte lysate test.     

Experiments on sexual isolation between Chilean and European strains ofDrosophila subobscura

Summary Males and females of Chilean strains ofDrosophila subobscura exhibit a pronounced tendency toward homogamic mating. This tendency shows a clear relation to the distance between the geographic localities from which the respective strains came. Nevertheless, when the Chilean flies are confronted with European strains, the ethological isolation is observed in some cases but not in others, depending on the geographic origin of the strains.Acknowledgments. This work has been partially supported by grants from the Univ. of Chile (Project B 729-8345) and PNUD/UNESCO (RLA 78/024). We are most grateful to Prof. D. Sperlich of the University of Tübingen who provided theD. subobscura strains from Tübingen and Sicily, and Prof. A. Prevosti from the University of Barcelona and R. de Frutos from the University of Valencia who provided the strains of Mallorca and Almería. We are finally obliged to Mr E. Zárate for his technical assistance.     

Lysozyme inhibitor conferring bacterial tolerance to invertebrate type lysozyme

Invertebrate (I-) type lysozymes, like all other known lysozymes, are dedicated to the hydrolysis of peptidoglycan, the major bacterial cell wall polymer, thereby contributing to the innate immune system and/or digestive system of invertebrate organisms. Bacteria on the other hand have developed several protective strategies against lysozymes, including the production of periplasmic and/or membrane-bound lysozyme inhibitors. The latter have until now only been described for chicken (C-) type lysozymes. We here report the discovery, purification, identification and characterization of the first bacterial specific I-type lysozyme inhibitor from Aeromonas hydrophila, which we designate PliI (periplasmic lysozyme inhibitor of the I-type lysozyme). PliI has homologs in several proteobacterial genera and contributes to I-type lysozyme tolerance in A. hydrophila in the presence of an outer membrane permeabilizer. These and previous findings on C-type lysozyme inhibitors suggest that bacterial lysozyme inhibitors may have an important function, for example, in bacteria-host interactions.     

The chromosomes ofBufo rubropunctatus andBufo chilensis (Anura,Bufonidae) and other species of thespinolosus group

Summary The chromosomes ofBufo rubropunctatus andB. chilensis (on basis of adults) are described for the first time. These chromosomic sets are compared with the karyotypes ofB. spinolosus andB. variegatus and other species ofspinolosus group. The importance of the secondary constrictions applied to the phylogeny ofBufo are discussed.Supported by Proyecto N⁰ S-77-47, Dirección de Investigación, Universidad Austral de Chile.I would like to thank Dr J. M. Cei for collecting the Argentinian toads. Mr N. Diaz collected the specimens from Santiago, Chile.The technical assistence of Sonia Lacrampe is acknowledged with appreciation.