The sequence variability of the ribosomal internal transcribed spacer (ITS) region, which comprises the 5.8 gene and the flanking regions ITS1 and ITS2, was investigated in the arbuscular mycorrhizal fungus Gigaspora margarita. DNA analysis of a multispore preparation and three single spores led to the identification of 11 slightly different sequences (three variants within a single spore), indicating substantial intersporal and intrasporal genetic variability (up to 9% sequence divergence). The sequence variations inside a single spore may be higher than that observed between spores. Even so, primers designed on the ITS1 and ITS2 regions identified Gi. margarita isolates and detected the endophyte during colonization.
The phylogeny of the Afro-Asian Lorisoidea is controversial. While postcranial data attest strongly to the monophyly of the Lorisidae, most molecular analyses portray them as paraphyletic and group the Galagidae alternately with the Asian or African lorisids. One of the problems that has bedevilled phylogenetic analysis of the group in the past is the limited number of taxa sampled for both ingroup families. We present the results of a series of phylogenetic analyses based on 635 base pairs (bp) from two mitochondrial genes (12S and 16S rRNA) with and without 36 craniodental characters, for 11 galagid and five lorisid taxa. The outgroup was the gray mouse lemur (Microcebus murinus). Analyses of the molecular data included maximum parsimony (MP), neighbor joining (NJ), maximum likelihood (ML), and Bayesian methods. The model-based analyses and the combined "molecules+morphology" analyses supported monophyly of the Lorisidae and Galagidae. The lorisids form two geographically defined clades. We find no support for the taxonomy of Galagidae as proposed recently by Groves [Primate Taxonomy, Washington, DC: Smithsonian Institution Press. 350 p, 2001]. The taxonomy of Nash et al. [International Journal of Primatology 10:57-80, 1989] is supported by the combined "molecules+morphology" analysis; however, the model-based analyses suggest that Galagoides may be an assemblage of species united by plesiomorphic craniodental characters.
The formaldehyde (FA) genotoxic potential in occupationally exposed individuals is conflicting. A relevant indoor-air FA pollution was found in hospitals and scientific institutions where FA is used as a bactericide and tissue preservative. In the present study, we evaluated the frequency of chromosomal aberrations (CAs) in peripheral blood lymphocytes from workers in pathology wards who have been exposed to FA, compared with a group of unexposed subjects. The subjects were also analyzed for the GSTM1 and GSTT1 metabolic gene polymorphisms. The exposed subjects showed a significant increase in the frequency of CA per cell and in the percentage of cells with aberrations compared to control subjects. The different GST genotypes did not affect the level of cytogenetic damage since CA frequencies were not statistically different between the GST "null" genotypes and the GST "positives". The generalized linear models showed that the number of CAs and cells with CAs increased with age, but, independent of age, it was significantly higher in the experimental rather than in the control group. Cubic-spline regression confirmed the linear relationship between CAs and age, but it provided evidence for a non-linear relationship between CAs and the number of years of FA exposure. Similar results were observed when the model included the number of cells with CAs as dependent variables. Our results demonstrate that air FA induces CAs even consequently to low levels of daily exposure, indicating an increased risk of genetic damage for workers exposed to this air pollutant.
Chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) frequencies were estimated in peripheral lymphocytes from 21 radiology technicians, and from 21 nonexposed control subjects. We exclusively considered individuals who neither smoke nor consume drugs or alcohol for a period of at least two years prior to the analysis. Significant differences were found between exposed and controls in terms of SCEs and CAs frequencies. Technicians showed a significant higher number of high-frequency individuals (HFIs) with respect to the control group. Nevertheless, the mean frequency of SCEs observed among technician HFIs did not significantly differ with respect to that observed among control HFIs. Vice versa, the nonHFIs belonging to technicians group showed a statistically higher difference in the SCEs/NSM value with respect to the non-HFIs belonging to control group. Since the differences in the SCEs frequencies between the two groups are due to non-HFIs, our results seem to indicate a general genotoxic effect of the IR, not affected by HFIs. Among technicians, the level of chromosome damage correlated neither with years of radiation exposure nor with the age of the subjects. Vice versa, in the control group, a positive correlation was found between the number of SCEs and age. In both samples the gender status did not influence the frequencies of CAs and SCEs. Our results suggest that chronic long-term exposure to low doses of ionizing radiation could increase the CAs and SCEs frequencies. This study reinforces the relevance of the biomonitoring of hospital workers chronically exposed to ionizing radiation.
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