Two new species of oribatid mites of the genus Truncozetes (Acari,Oribatida, Epactozetidae) from?Ecuador

Two new oribatid mite species of the genus Truncozetes (Oribatida, Epactozetidae), Truncozetes ecuadoriensis sp. n. and Truncozetes monodactylus sp. n., are described from the Ecuadorian soils. The morphology of the gnathosoma and the legs is presented in detail for the first time for the species of Truncozetes. An identification key to all known species of the family Epactozetidae is given.     

Cytosolic ascorbate peroxidase in Gymnosperms

ABSTRACT

Sixteen species of Gymnosperms have been screened for cytosolic ascorbate peroxidase by means of native polyacrylamide gel electrophoresis. This analysis shows that a single form of the enzyme is the most common situation. The enzyme reveals a similar electrophoretic mobility in species belonging to the same genus and sometimes to different genera. In some Pinaceae, two bands of activity were observed. The presence in the archaic spermatophyte Ginkgo biloba, as well as in the more advanced monocotyledons, of three isoforms of ascorbate peroxidase, might suggest that three different cytosolic ascorbate peroxidase genes were already present in this archaic species.     

Scapharca inæquivalvis Tetrameric Hemoglobin A and B Genes: Evidence for a Minigene

Vertebrate and many invertebrate globin genes have a three-exon/two-intron organization, with introns in highly conserved positions. According to the ``intron early' hypothesis, introns are the vestigial segments which flank previously independent coding sequences, thus providing evidence for the assembly of the ancient proteins by ``exon shuffling.' In this paper, we report the analysis of the genes of the bivalve mollusk Scapharca inaequivalvis tetrameric hemoglobin (HbII), which support this hypothesis, at least for the hemoglobin genes. We show the existence of ``minigenes' in the IIA and IIB globin genes, spanning part of the first and second introns, ``in frame' with the heme-binding domain coded by the second exon. Further support for the exon shuffling hypothesis can be found in the degree of identity of the ``new' translated sequences with those flanking the central protein domain of some invertebrate hemoglobins. Received: 31 July 1997 / Accepted: 12 December 1997     

Effects of three strains of bifidobacteria on cholesterol

To determine the validity of the hypothesis of assimilation or precipitation of cholesterol by Bifidobacterium species, resting cell assays and cultures were undertaken in TPY medium containing oxgall. With resting cell assays (pH 5), cholesterol was precipitated and redissolved in phosphate buffer (pH 7). At the end of the cultures, only part of the removed cholesterol from the culture medium was found in the phosphate buffer, while the missing cholesterol was in cell extracts. It appeared that removal of cholesterol during culturing was not solely due to its precipitation. It is concluded that growing bifidobacteria cells are able to remove cholesterol both by precipitation and assimilation.     

New cases of thalidomide embryopathy in Brazil

Thalidomide is the best known human teratogen. Although withdrawn from the market in 1961, thalidomide was remarketed after 1965 in several countries, for the treatment of erythema nodosum leprosum. Thalidomide has a potent immunomodulatory property and has now a number of approved and off-label uses in dermatologic, oncologic, infectious and gastrointestinal conditions. In the U.S., FDA approved the use of thalidomide in 1998, but no cases of thalidomide embriophaty were registered after that. Since 1996 no new cases were reported in Latin America. However, the Teratogen Information Service (TIS) Porto Alegre, recorded three new cases of thalidomide embriophaty born in Brazil since 2005. Considering that these three cases were not registered through a systematic surveillance system, but that came to our attention through a series of coincidental random events, it can be assumed that the actual occurrence of affected babies by thalidomide continues being as frequent as denounced ten years ago.     

Stable isotope ratios in hair and teeth reflect biologic rhythms

Biologic rhythms give insight into normal physiology and disease. They can be used as biomarkers for neuronal degenerations. We present a diverse data set to show that hair and teeth contain an extended record of biologic rhythms, and that analysis of these tissues could yield signals of neurodegenerations. We examined hair from mummified humans from South America, extinct mammals and modern animals and people, both healthy and diseased, and teeth of hominins. We also monitored heart-rate variability, a measure of a biologic rhythm, in some living subjects and analyzed it using power spectra. The samples were examined to determine variations in stable isotope ratios along the length of the hair and across growth-lines of the enamel in teeth. We found recurring circa-annual periods of slow and fast rhythms in hydrogen isotope ratios in hair and carbon and oxygen isotope ratios in teeth. The power spectra contained slow and fast frequency power, matching, in terms of normalized frequency, the spectra of heart rate variability found in our living subjects. Analysis of the power spectra of hydrogen isotope ratios in hair from a patient with neurodegeneration revealed the same spectral features seen in the patient's heart-rate variability. Our study shows that spectral analysis of stable isotope ratios in readily available tissues such as hair could become a powerful diagnostic tool when effective treatments and neuroprotective drugs for neurodegenerative diseases become available. It also suggests that similar analyses of archaeological specimens could give insight into the physiology of ancient people and animals.     

Spontaneous calcification process in primary renal cells from a medullary sponge kidney patient harbouring a GDNF mutation

Medullary nephrocalcinosis is a hallmark of medullary sponge kidney (MSK). We had the opportunity to study a spontaneous calcification process in vitro by utilizing the renal cells of a patient with MSK who was heterozygous for the c.‐27 + 18G>A variant in the GDNF gene encoding glial cell‐derived neurotrophic factor. The cells were obtained by collagenase digestion of papillary tissues from the MSK patient and from two patients who had no MSK or nephrocalcinosis. These cells were typed by immunocytochemistry, and the presence of mineral deposits was studied using von Kossa staining, scanning electron microscopy analysis and an ALP assay. Osteoblastic lineage markers were studied using immunocytochemistry and RT‐PCR. Staminality markers were also analysed using flow cytometry, magnetic cell separation technology, immunocytochemistry and RT‐PCR. Starting from p2, MSK and control cells formed nodules with a behaviour similar to that of calcifying pericytes; however, Ca₂PO₄ was only found in the MSK cultures. The MSK cells had morphologies and immunophenotypes resembling those of pericytes or stromal stem cells and were positive for vimentin, ZO1, αSMA and CD146. In addition, the MSK cells expressed osteocalcin and osteonectin, indicating an osteoblast‐like phenotype. In contrast to the control cells, GDNF was down‐regulated in the MSK cells. Stable GDNF knockdown was established in the HK2 cell line and was found to promote Ca₂PO₄ deposition when the cells were incubated with calcifying medium by regulating the osteonectin/osteopontin ratio in favour of osteonectin. Our data indicate that the human papilla may be a perivascular niche in which pericyte/stromal‐like cells can undergo osteogenic differentiation under particular conditions and suggest that GDNF down‐regulation may have influenced the observed phenomenon.