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Biomedical subjects

H Reichenbach

Publications and source records attributed to H Reichenbach.

At least 55 records · Page 3Linked to original sources
PubMed1994

The soraphens: a family of novel antifungal compounds from Sorangium cellulosum (Myxobacteria). I. Soraphen A1 alpha: fermentation, isolation, biological properties.

An antifungal activity was detected in the culture broth of Sorangium cellulosum (Myxococcales), strain So ce26. The activity was excreted into the supernatant during the log and early stationary phase. The active substance was quantitatively bound to XAD absorber resin added to the medium at the beginning of the fermentation. The new secondary metabolite was called soraphen and is of special interest to plant disease control for its inhibitory activity against numerous phytopathogenic fungi.

Antifungal Agents↗
PubMed1994

Crocacin, a new electron transport inhibitor from Chondromyces crocatus (myxobacteria). Production, isolation, physico-chemical and biological properties.

Crocacin was isolated from the biomass of the myxobacterium Chondromyces crocatus, strain Cm c3. It inhibited the growth of a few Gram-positive bacteria and a wide spectrum of yeasts and molds. In beef heart submitochondrial particles, crocacin blocked the electron transport within the bc1-segment (complex III) and caused a red shift in the reduced spectrum of cytochrome b with a maximum at 569 nm.

Anti-Bacterial Agents↗
PubMed1993

Biologically active secondary metabolites from myxobacteria.

New chemical structures with proven biological activity still are badly needed for a host of applications and are intensively screened for. Suitable compounds may be used as such, or in the form of their derivatives or, equally important, may serve as lead compounds for designing synthetic analogs. One way to new compounds is the exploitation of new producer organisms. During the past 15 years the myxobacteria have been shown in our laboratories to be a rich source of novel secondary metabolites, many of the compounds showing interesting and sometimes unique mechanisms of action. About 50 basic structures and nearly 300 structural variants have been elucidated, and almost all of them turned out to be new compounds. Several myxobacterial substances may have a good chance of an application.

Journal Article↗
PubMed1993

Rhizopodin, a new compound from Myxococcus stipitatus (myxobacteria) causes formation of rhizopodia-like structures in animal cell cultures. Production, isolation, physico-chemical and biological properties.

A new cytostatic compound, rhizopodin, was isolated from the culture broth of the myxobacterium, Myxococcus stipitatus. The compound inhibited growth of various animal cell cultures without killing the cells. The ID50, measured by an MTT assay, was 12 approximately 30 ng/ml, depending on the cell line. Especially cells growing fibroblast-like showed typical morphological changes. They became larger and within hour formed long branching and reticular runners. These morphological changes were irreversible. Rhizopodin suppresses bleb formation in K-562 cells, and therefore could act by interacting with protein phosphorylation.

Animals↗
PubMed1993

[Multiple abnormalities in a child with male karyotype due to familial partial Xp duplication].

A child with multiple abnormalities and intersexual external genitals is presented. The child has a male karyotype with a partial duplication Xp. Using additionally methods of molecular genetics the SRY-region was detected. We reviewed the only few persons described in the literature with male karyotype and partial duplications Xp. There are similarities in phenotype including sex inversion or intersexual genitals if the duplication is localised in the region Xp 21-->Xp 22. Whether these affected patients represent a new syndrome is a moot point. We also found the aberrant X-chromosome in the mother of the child. In the present pregnancy of the mother there is, therefore, a risk of recurrence.

Abnormalities, Multiple↗
PubMed1993

[A further case with Baller-Gerold syndrome (craniosynostosis--radial aplasia syndrome)--overview and new viewpoints on a rare syndrome].

The Baller-Gerold syndrome is a rare malformation syndrome with craniosynostosis. A radial defect is the main feature of this combination besides the premature craniosynostosis. The entity and the etiology of this inherited trait was often discussed in recent years. This syndrome is further characterised and presented as a distinct entity with the reported new case. Parents of such a child should be aware of the 25% recurrence risk in subsequent siblings because of an autosomal recessive mode of inheritance.

Acrocephalosyndactylia↗
PubMed1993

[Brachydactyly type A4 (brachymesophalangia II and V, Temtamy type). A rare type of brachydactyly].

Brachydactyly is classified into 5 main types. In type A brachydactylies the shortening is mainly confined to the middle phalanges of the digits and toes. Brachydactyly type A4 is characterised by brachymesophalangy II and V. We found this rare type of brachydactyly in a child and his mother. We examined the hands and feet of these individuals radiologically. The reported malformation had affected members of 2 respectively 3 generations. There is no doubt about the autosomal dominant mode of inheritance.

Bone Diseases, Developmental↗
PubMed1992

[The heart-hand syndrome. A new variant of disorders of heart conduction and syndactylia including osseous changes in hands and feet].

A male infant was born at the 36th week of gestation by cesarean section because of an intrauterine bradycardy. There was a 2nd degree a. v.-bloc postnatal. The heart rate was normal after the 5th day of life with a QT-interval of 150 percent resp. 120 percent after the 15th day. Additionally there were syndactylies of hands and feet. The infant suddenly died at the age of 5 months. Examination of the parents revealed a QT-interval of 115 percent as well as synostoses of the carpus in the father. These microsymptoms are very important for genetic counseling of the family. There is a recurrence risk of 50 percent for further children because a dominant trait is to be suggested.

Electrocardiography↗
PubMed1989

Myxochelin A, a new iron-chelating compound from Angiococcus disciformis (Myxobacterales). Production, isolation, physico-chemical and biological properties.

Myxochelin A, a new catechole siderophore, was isolated from the culture broth of the myxobacterium, Angiococcus disciformis strain An d30. As is the case with other iron-chelating compounds the production of myxochelin A could be markedly increased up to 44 mg/liter by fermentation at low iron concentrations (10(-7) M FeCl3). The new substance showed weak activity against some bacteria.

Chemical Phenomena↗
PubMed1988

Utilization of IncP-1 plasmids as vectors for transposon mutagenesis in myxobacteria.

No free plasmid has ever been found in the myxobacterium Myxococcus xanthus, but IncP-1 plasmids are able to integrate into the chromosome of this bacterium. The frequency of integration depends greatly upon the structure of the IncP-1 plasmid used. This property has been used to devise new delivery systems for transposon mutagenesis in this species. Plasmids with low integration efficiencies have proved to be efficient donors of Tn5, while plasmids with very high frequencies of integration could be used directly to generate mutations. These vectors have also proved efficient for Tn5 transfer into other species of myxobacteria, which have not so far been susceptible to genetic analysis.

DNA Transposable Elements↗
PubMed1988

Saframycin Mx1, a new natural saframycin isolated from a myxobacterium.

A new natural saframycin was discovered in the culture broth of the myxobacterium, Myxococcus xanthus strain Mx x48. The fermentation and isolation of the antibiotic are described. The name, saframycin Mx1, is proposed. The compound appears to interact with cellular DNA.

Anti-Bacterial Agents↗
PubMed1987

The aurachins, new quinoline antibiotics from myxobacteria: production, physico-chemical and biological properties.

The aurachins, new quinoline alkaloids, were extracted with acetone from the biomass of the myxobacterium, Stigmatella aurantiaca strain Sg a15 and purified by column chromatography. The four described aurachins A, B, C and D, were inhibitory for Gram-positive bacteria and a few yeasts and molds. They blocked NADH oxidation in beef heart submitochondrial particles.

Anti-Bacterial Agents↗
PubMed1987

The sorangicins, novel and powerful inhibitors of eubacterial RNA polymerase isolated from myxobacteria.

A new antibiotic, sorangicin, was isolated from the culture supernatant of the myxobacterium, Sorangium (Polyangium) cellulosum strain So cel2. It is a macrocyclic lactone carbonic acid and is produced in two structural variants, sorangicins A and B. In addition small quantities of the respective glycosides, sorangiosids A and B, may be found. The antibiotic acts mainly against Gram-positive bacteria, including myocobacteria, with MIC values between 0.01 and 0.1 microgram/ml, but at higher concentrations (MIC 3 approximately 30 micrograms/ml) Gram-negatives are also inhibited. Yeasts and molds are completely resistant. The new antibiotic is a specific inhibitor of eubacterial RNA polymerase which it blocks, however, only if added before RNA polymerization has started.

Aminoglycosides↗
PubMed1986

Determination of bacterial ammonia pools using Myxococcus virescens as an example.

Samples (150 microliters) from liquid cultures of known cell density of Myxococcus virescens (Myxobacterales) were used for the determination of the intracellular NH3/NH+4 concentrations (= total ammonia). The cells were separated from the culture broth within 30 s by centrifugation through a silicone layer and were lysed immediately with 20 microliters of a disintegration liquid at the bottom of the centrifugation tube. The ammonia concentrations of the lysates were determined with a Dohrmann nitrogen analyzer. The intracellular ammonia concentrations were calculated after corrections for trapped supernatant had been made by adding radioactive glucose, which cannot be taken up by the organism. Control experiments with permeabilized cells and radioactive methylamine corroborated the reliability of the method.

Ammonia↗
PubMed1986

The myxobacteria: common organisms with uncommon behaviour.

The gliding myxobacteria, common and easily obtainable soil organisms, exhibit a fascinating social organization which culminates in the formation of fruiting bodies by an ordered cooperation of hundreds of thousands of cells. Inside the fruiting body, the vegetative cells transform themselves into dormant myxospores. The myxobacteria have become potent model systems for studying morphogenetical problems at the prokaryotic organizational level, particularly since the methods of modern genetics now may be readily applied to them.

Base Composition↗