Proflavin: an unusual mutagen

In the Salmonella typhimurium mutagenicity assay, proflavin (PF), in the dark, was shown to possess some direct-acting frameshift mutagenic activity for strains TA1537 and TA98. In the presence of microsomal enzymes from mouse, hamster and rat livers, frameshift mutagenic activity for strain TA1538 and enhanced mutagenicity for strain TA1537 was observed. Exposure of bacteria to PF in the presence of visible light resulted in base substitution (strain TA1535) as well as frameshift (TA1537, TA1538, TA98) genetic activities. The findings are taken to indicate that PF possesses direct-acting frameshift activity (TA1537 and TA98) by virtue of its ability to intercalate between DNA basepairs. The frameshift activity (TA1538, TA98 and enhanced TA1537) seen following metabolic or photo-activation may be due to the formation of chemical adducts between the cellular DNA and oxidation products of PF (a base-displacement effect). The light-induced base-substitution activity probably results from the generation of singlet oxygen which reacts with the guanine moiety of DNA. The mutagenic photoproduct of PF appears to be stable.     

Cyclopia-synotia: an unusual presentation

An infant showing an unusual combination of craniofacial abnormalities is described. Synotia, astomia, a rudimentary proboscis, and a central placode in the hairline were observed. Serial sections of the head were examined microscopically. The proboscis contained a mass of striated muscle, but no bony or nervous tissue. Cyclopia was suggested by the central placode, the latter consisting of a thin, stratified, squamous nonkeratinized epithelium attached to an incomplete orbit by a strand of connective tissue. The orbit consisted of a bony shelf with bundles of nerves, striated muscle, and degenerate retinal tissue. The central nervous system cranial to the hindbrain was poorly developed. The midbrain and diencephalon were rudimentary, and there was poor separation of the small cerebral hemispheres. The auditory system was well represented. The maxilla and mandible were present, but there was no evidence of tooth formation. The wide range of midline abnormalities and anodontia suggest that this is a case of cranial neural crest deficiency.     

Biological and chemical diversity go hand in hand: Basidiomycota as source of new pharmaceuticals and agrochemicals

The Basidiomycota constitutes the second largest higher taxonomic group of the Fungi after the Ascomycota and comprises over 30.000 species. Mycelial cultures of Basidiomycota have already been studied since the 1950s for production of antibiotics and other beneficial secondary metabolites. Despite the fact that unique and selective compounds like pleuromutilin were obtained early on, it took several decades more until they were subjected to a systematic screening for antimicrobial and anticancer activities. These efforts led to the discovery of the strobilurins and several hundreds of further compounds that mainly constitute terpenoids. In parallel the traditional medicinal mushrooms of Asia were also studied intensively for metabolite production, aimed at finding new therapeutic agents for treatment of various diseases including metabolic disorders and the central nervous system. While the evaluation of this organism group has in general been more tedious as compared to the Ascomycota, the chances to discover new metabolites and to develop them further to candidates for drugs, agrochemicals and other products for the Life Science industry have substantially increased over the past decade. This is owing to the revolutionary developments in –OMICS techniques, bioinformatics, analytical chemistry and biotechnological process technology, which are steadily being developed further. On the other hand, the new developments in polythetic fungal taxonomy now also allow a more concise selection of previously untapped organisms. The current review is dedicated to summarize the state of the art and to give an outlook to further developments.     

Carbon monoxide: an unusual drug

The highly toxic gas carbon monoxide (CO) displays many physiological roles in several organs and tissues. Although many diseases, including cancer, hematological diseases, hypertension, heart failure, inflammation, sepsis, neurodegeneration, and sleep disorders, have been linked to abnormal endogenous CO metabolism and functions, CO administration has therapeutic potential in inflammation, sepsis, lung injury, cardiovascular diseases, transplantation, and cancer. Here, insights into the CO-based therapy, characterized by the induction or gene transfer of heme oxygenase-1 and either gas or CO-releasing molecule administration, are reviewed.     

Atrial fibrillation: an unusual cause

A 28-year-old male presenting with atrial fibrillation (AF) underwent successful electrical cardioversion to restore sinus rhythm. He had no prior history of AF or other cardiac disease. However, transthoracic echocardiography (TTE), performed to exclude structural abnormalities as a cause of AF, demonstrated a large mass in the left atrium (LA). For further analysis the patient was referred to our centre, and echocardiography, multislice detector computed tomography (MDCT) and cardiovascular magnetic resonance imaging (CMR) were performed for further noninvasive diagnostic work-up.     

Meckel's syndrome: an unusual pedigree

The authors report the case, in the same family, of two children with the Meckel's syndrome, of two mis-arriages (one foetus with anencephalia, the other one with occipital meningocele), and of two still-born children (one with anencephalia, the other one with occipital meningocele). The genetic problems raised by this unusual genealogy are discussed.     

The Amaryllidaceae alkaloids: an untapped source of acetylcholinesterase inhibitors

Phytochemistry Reviews - The AChE inhibitory activity of alkaloid extracts and compounds has been in the focus of research on the plants of Amaryllidoideae subfamily since the approval of...     

A nose that looks like a hand and acts like an eye: the unusual mechanosensory system of the star-nosed mole

The star-nosed mole (Condylura cristata) has a snout surrounded by 22 fleshy and mobile appendages. This unusual structure is not an olfactory organ, as might be assumed from its location, nor is it used to manipulate objects as might be guessed from its appearance. Rather, the star is devoted to the sense of touch, and for this purpose the appendages are covered with thousands of small mechanoreceptive Eimer's organs. Recent behavioral studies find that the star acts much like a tactile eye, having a small behavioral focus, or “fovea” at the center – used for detailed explorations of objects of interest. The peripheral and central nervous systems of the mole reflect these behavioral specializations, such that the small behavioral focus on the nose is more densely innervated in the periphery, and has a greatly enlarged representation in the somatosensory cortex. This somatosensory representation of the tactile fovea is not correlated with anatomical parameters (innervation density) as found in other species, but rather is highly correlated with patterns of behavior. The many surprising parallels between the somatosensory system of the mole, and the visual systems of other mammals, suggest a convergent and perhaps common organization for highly developed sensory systems. Accepted: 31 May 1999