Nucleotide sequence, secondary structure and evolution of the 5S ribosomal RNA from five bacterial species

The nucleotide sequences of the 5S ribosomal RNAs of the bacteria Agrobacterium tumefaciens, Alcaligenes faecalis, Pseudomonas cepacia, Aquaspirillum serpens and Acinetobacter calcoaceticus have been determined. The sequences fit in a generally accepted model for 5S RNA secondary structure. However, a closer comparative examination of these and other bacterial 5S RNA primary structures reveals the potential of additional base pairing and of multiple equilibria between a set of slightly different alternative secondary structures in one area of the molecule. The phylogenetic position of the examined bacteria is derived from a 5S RNA sequence alignment by a clustering method and compared with the position derived on the basis of 16S ribosomal RNA oligonucleotide catalogs.     

Morphologische untersuchungen an zwei drüsentypen (Thoraxdrüse,Mandibeldrüse) von Lepidopterenraupen

Two types of possibly homologous glands different in structure and formation have been found. One of them is represented in C. vinula L. and N. anceps Goeze, it is an endocrine organ. The other in S. ligustri, S. ocellata, M. neustria and L. monacha has an excretory duct and therefore is an exocrine organ.

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Mit dankenswerter Unterstützung der Deutschen Forschungsgemeinschaft.     

Characterization of the Rhizobium leguminosarum biovar phaseoli nifA gene,a positive regulator of nif gene expression

We report the isolation, mutational analysis and the nucleotide sequence of the Rhizobium leguminosarum bv. phaseoli nifA gene. Comparison of the deduced amino acid sequence with other NifA sequences indicated the presence of the conserved central activator and the C-terminal DNA-binding domains. Nodules elicited by a R. leguminosarum bv. phaseoli nifA mutant were symbiotically ineffective. The expression of a nifA-gusA fusion was shown to be independent on the oxygen status of the cell. We cloned the three nifH copies of R. leguminosarum bv. phaseoli and determined the nucleotide sequence of their promoter regions. The expression of nifH-gusA fusions is induced under microaerobic conditions and is dependent on the presence of NifA.Abbreviations bp base pair(s) - kb kilobase(s) - ORF open reading frame     

Agitation,aeration and perfusion modules for cell culture bioreactors

For an optimized bioreactor design which is adapted to the cultivation of sensitive animal cells different modular bioreactor components for gentle agitation, sufficient aeration and long-term perfusion were developed and investigated with respect to their suitability from laboratory to production scale. Aeration systems have been designed for both shear sensitive cells and cells which tolerate bubbles. The systems are based on either membranes for bubble-free aeration or stainless steel sparger systems. They were characterized by determination of their oxygen transfer capacity and optimized in cultivation processes of different cell lines under process conditions such as batch and perfusion mode.Different impellers for suspension cells and cells grown on carriers were investigated for their suitability to ensure homogeneous gentle mixing. A large pitch blade impeller as well as a novel 3-blade segment impeller are appropriate for homogeneous mixing at low shear rates. Especially with the 3-blade segment impeller fluid mechanical stress can be reduced at a given stirrer speed which is advantageous for the cultivation of cells attached to microcarriers or extremely shear sensitive suspension cells. However, our results indicate that shear sensitivity of animal cells has been generally overestimated.Continuous perfusion of both suspension cell cultures and cells cultivated on microcarriers could be successfully performed over extended periods of time using stainless steel spinfilters with appropriate pore sizes and systems based on microporous hydrophilic membranes. Spinfilters are suitable cell retention systems for technical scale bioreactors allowing continuous perfusion cultures of suspension cells (pore size 10 to 20 m) as well as anchorage dependent cells grown on microcarriers (pore size 75 m) over six weeks to 3 months.Applying the developed modules for agitation, aeration and perfusion process adapted bioreactor set-ups can be realized which ensure optimum growth and product formation conditions in order to maximize cell and product yields.     

The nucleotide sequences of the 5 S rRNAs of seven molds and a yeast and their use in studying ascomycete phylogeny.

The sequences of the 5 S rRNAs isolated from 8 ascomycete species belonging to the genera Aspergillus, Penicillium, Acremonium and Candida are reported. Two of the examined strains each yielded a mixture of 3 slightly different 5 S RNAs, which were individually sequenced after fractionation. A previously published sequence for Aspergillus nidulans 5 S RNA was found to contain errors. Reconstruction of an evolutionary tree based on 5 S RNA sequences showed that the 16 presently examined ascomycetes form three clusters. The same threefold partition can be observed in the secondary structure pattern, each cluster showing a slightly different variant of the general 5-helix model for 5 S rRNA (De Wachter, Chen and Vandenberghe (1982) Biochimie 64, 311-329), and different sets of secondary structure equilibrium forms in helices C and E of the aforementioned model.     

The use of light green and organge II as quantitative protein stains,and their combination with the feulgen method for the simultaneous determination of protein and DNA

Summary The protein dyes Light Green and Orange II were studied separately and in combination with the Feulgen-Pararosanilin(SO₂) and-Thionin(SO₂) method for the simultaneous determination of DNA and protein. — With polyacrylamide modelfilms the pH dependency, specificity and stoichiometry of Light Green and Orange II have been investigated. The results of both staining methods with different biological objects have been compared. — In addition, the Feulgen-Thionin(SO₂) method was studied with model films with respect to its specificity and stoichiometry. In biological objects it has been compared with the Feulgen-Pararosanilin(SO₂) method. — When combining the Light Green staining with the Feulgen-Pararosanilin(SO₂) procedure and the Orange II staining with Feulgen-Thionin-(SO₂), both Feulgen-DNA stainings, which were first applied, proved to be unaffected by the following protein staining procedure. When the Feulgen procedure was carried out without the dye, followed by Light Green staining, the latter became reduced when a sulfite water rinse was included but was unaffected when a running tap water rinse was used. In the case of the Orange II staining a serious reduction in dye binding capacity was found in both situations. — When the Feulgen-Pararosanilin(SO₂) Light Green procedure was carried out on isolated nuclei with all dyes present, a decrease of protein dye binding was observed, similar to that found with the well-known Feulgen-Pararosanilin(SO₂) Naphthol Yellow S combination. It is concluded that in spite of this reduction the latter two combinations can be used for the cytophotometric analysis of DNA and protein in the same object.This work was supported by the Dutch Cancer Foundation Koningin Wilhelmina Fonds grant NUKC 1981-15     

The ultrastructure of campaniform sensilla on the eye of the cricket,Gryllus campestris

Summary The structure of the campaniform sensilla of the cricket eye was investigated by light and electron microscopy. Each sensillum is innervated by a single bipolar neuron. Its axon extends through the retina into a side-branch of the nervus tegumentarius. The dendrite extends through a cuticular channel to the surface of the cornea. The distal part of the dendrite, the sensory process, contains a tubular body and is attached to a cuticular cap which is obliquely inserted into the exocuticle between the corneal lenslets. Some particular structural features as well as the function of the campaniform sensillum of the cricket eye are discussed.Supported by the Deutsche Forschungsgemeinschaft, grant Ho 463/10The authors are indebted to Prof. H. Altner, University of Regensburg, and Mrs. Evelyn Thury, Contron GmbH, München for use of the scanning electron microscope facilities