Human Karyotyping by Heat-Giemsa Staining and Comparison with Fluorochrome Techniques

CHARACTERISTIC patterns resembling those revealed by the fluorochrome techniques¹ appear along human mitotic metaphase chromosomes when methanol-acetic acid-fixed preparations are heated to 69° C and stained with Giemsa solution. This procedure is a greatly simplified version of one developed by F. E. Arrighi and T. C. Hsu (personal communication) which heavily stains the centromere regions and produces distinct patterns on the chromosome arms. We chose the conditions for pretreatment of the preparations on the basis of the finding of Marmur and Doty² that the transition temperature, that is, the temperature at which the double helical configuration of DNA changes to a disordered coiling, for adenine-thymine nucleotide pairs, is 69° C. For cytosine-guanine pairs they found that the transition temperature is 110° C. Heating to the lower transition temperature should therefore denature regions of DNA rich in adenine-thymine pairs, leaving regions rich in cytosine-guanine pairs intact; such differences might be reflected in the staining properties, although the differential staining that occurs after heat treatment is obviously open to alternative interpretations.     

Major morphological changes in a Lake Victoria cichlid fish within two decades

During the upsurge of the introduced predatory Nile perch in Lake Victoria in the 1980s, the zooplanktivorous Haplochromis ( Yssichromis ) pyrrhocephalus nearly vanished. The species recovered coincident with the intense fishing of Nile perch in the 1990s, when water clarity and dissolved oxygen levels had decreased dramatically due to increased eutrophication. In response to the hypoxic conditions, total gill surface in resurgent H. pyrrhocephalus increased by 64%. Remarkably, head length, eye length, and head volume decreased in size, whereas cheek depth increased. Reductions in eye size and depth of the rostral part of the musculus sternohyoideus, and reallocation of space between the opercular and suspensorial compartments of the head may have permitted accommodation of larger gills in a smaller head. By contrast, the musculus levator posterior, located dorsal to the gills, increased in depth. This probably reflects an adaptive response to the larger and tougher prey types in the diet of resurgent H. pyrrhocephalus . These striking morphological changes over a time span of only two decades could be the combined result of phenotypic plasticity and genetic change and may have fostered recovery of this species.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 41–52.     

Development of microsatellite markers for the red‐listed wood‐decay fungus Phlebia centrifuga

Seven polymorphic microsatellite markers were developed for the wood‐decay basidiomycete Phlebia centrifuga. The primers were identified using two techniques, based on intersimple sequence repeats (ISSR) and amplified fragment length polymorphism (AFLP), respectively. The markers were screened on 27 isolates from Europe and North America. Two markers varied only on a worldwide scale, but not within Europe. The other five showed variation on both scales. These markers will now be used to characterize populations of P. centrifuga, which is red‐listed as near‐threatened in its natural habitat due to human disturbance.     

Are Robertsonian variations a frequent phenomenon in mouse populations in Eurasia?

We examined the karyotypes of 212 specimens of the house mouse obtained from 44 localities in central and eastern Europe, and several regions of Asia. The Robertsonian chromosome fusion 5.12 was found in a population of Mus musculus musculus in Czechoslovakia. Two large HSRs on chromosome 1 were ascertained in four female mice from western Siberia. In most of the localities under study, the mice possessed a normal karyotype with 40 acrocentric chromosomes.     

Breeding of the Seychelles Magpie Robin Copsychus sechellarum and implications for its conservation

The total population of the Seychelles Magpie Robin Copsychus sechellarum declined from 38–41 birds in 12–13 territories in 1977–1978 to 17–21 birds in eight to nine territories in 1988–1990 and was entirely confined to Fregate Island (210 ha) in the Seychelles. After a successful cat eradication program in 1981–1982, recruitment improved, although the abandonment of agriculture had caused a reduction in the amount of feeding habitat and hence in the carrying capacity of the island. The population declined because of the failure of recruitment to compensate for the annual adult mortality. Foraging activity of the Magpie Robin was greater in high-quality territories (measured by soil invertebrates available), leading to increased reproductive success. Through supplementary feeding, five times as many recruits were produced. Of the 11.5 potential annual breeding recruits, 5.3 are required to compensate for adult mortality, and the other 6.2 recruits can be regarded as “surplus” contributing to an increase. Magpie Robins prefer to breed in rotten trees, which are a scarce resource. The greater the distance between the nest site and feeding areas, the less time was spent in incubation and nest guarding, resulting in greater egg loss. Because of lack of suitable areas for establishing territories, many young Magpie Robins became “floaters”. Nest disturbance, both by these floaters and by the introduced Indian Mynah Acridotheres tristis, had adverse effects on the breeding success of robins. A recovery plan has been designed to save the Magpie Robin. Territories have been improved for feeding (by tree planting) and for breeding (by providing nestboxes and reducing nest disturbances). Given the vulnerability of one small island, the presence of surplus birds (supported mainly by supplementary food) and the suitability of neighbouring Aride Island (68 ha), successful translocations to this island took place in 1992 and 1994. Given the presence now of 47 individuals on two islands, it is hoped that the species will pull back from the brink of extinction.     

Characterization of Encephalitozoon (Septata) intestinalis Isolates Cultured from Nasal Mucosa and Bronchoalveolar Lavage Fluids of Two AIDS Patients

ABSTRACT. Microsporidia are obligate intracellular protozoan parasites that can cause opportunistic infections in AIDS patients. Species from five genera of microsporidia are presently known to infect man. One species, Septata intestinalis originally was detected in stool specimens of individuals with chronic diarrhea and subsequently was found to disseminate to the kidneys, lungs, and nasal sinuses. This organism has since been reclassified as Encephalitozoon and in this study, we report the culture of Encephalitozoon intestinalis from a bronchoalveolar lavage specimen and a nasal mucus aspirate of two AIDS patients living in the USA. The bronchoalveolar and nasal microsporidian isolates grew in several continuous cell lines including RK-13, MDCK, HT-29, Caco-2, Vero, and 1047. Transmission electron microscopy of the clinical and cell culture specimens revealed that the new isolates appeared to be E. intestinalis based on morphology and growth of organisms in septated membrane-bound parasitophorous vacuoles. The new E. intestinalis isolates were characterized and compared with the first isolated E. intestinalis that was cultured from stool to confirm their identity and to determine if there existed any minor differences, as seen in the closely related Encephalitozoon cuniculi strains. By the methods of sodium dodecyl sulfate-polyacrylamide gel electrophoresis staining for proteins and carbohydrates, Western blot immunodetection, and polymerase chain reaction-based methods with restriction endonuclease digestion, double-stranded DNA heteroduplex mobility shift analysis, and DNA sequencing of the ribosomal DNA intergenic spacer region, the new isolates were identical to each other and to the reference isolate of E. intestinalis. In addition, with any of these methods, the E. intestinalis organisms could be distinguished from the three E. cuniculi strains, Encephalitozoon hellem, and Vittaforma corneae, which is important for diagnostics, therapeutic strategies, and epidemiology.     

NEOSELACHIAN SHARK AND RAY TEETH FROM THE VALANGINIAN, LOWER CRETACEOUS, OF WĄWAŁ, CENTRAL POLAND

Abstract:  Valanginian strata at Wąwał in central Poland have yielded the oldest marine neoselachian assemblages from the Cretaceous of Europe. The faunas comprise seven taxa including Heterodontus polonicus sp. nov., an indeterminate orectolobiform, Protolamna sp., Palaeoscyllium sp., Synechodus nitidus , Squatina cranei and Belemnobatis sp. Heterodontus polonicus is recognized primarily by the high amount of reticulate ornamentation on the lower labial side of the anterior teeth. The faunas from Wąwał are numerically dominated by neoselachian genera such as Synechodus , Heterodontus and Belemnobatis that were already well established in the Jurassic. More modern taxa include the oldest recorded occurrence of the true Squatina -lineage, and the presence of Protolamna is one of the earliest undoubted lamniform occurrences so far reported.