Orthovanadate increased the frequency of aneuploid mouse sperm without micronucleus induction in mouse bone marrow erythrocytes at the same dose level

The objective of the current study was to investigate the ability of orthovanadate to induce aneuploidy in mouse sperm and micronuclei in mouse bone marrow cells at the same dose levels. The BrdU-incorporation assay was performed to test if the chemical treatment altered the duration of the meiotic divisions. It was found that orthovanadate (25mg/kg bw) treatment did not cause meiotic delay. To determine the frequencies of hyperhaploid and diploid sperm, male mice were treated by intraperitoneal (i.p.) injection with 5, 15 or 25mg/kg bw orthovanadate and sperm were sampled from the Caudae epididymes 22 days later. Fluorescence in situ hybridization (FISH) was performed with DNA-probes for chromosomes 8, X or Y. Significant increases in the frequencies of total hyperhaploid sperm (p<0.01) were found with 15 and 25mg/kg bw orthovanadate, indicating induced non-disjunction during male meiosis. The dose-response was described best by a linear equation. Orthovanadate did not significantly increase the frequencies of diploid sperm at any of the three doses tested, indicating that no complete meiotic arrest occurred. Orthovanadate was investigated also by the micronucleus test at i.p. doses of 1, 5, 15 or 25mg/kg bw, followed by bone marrow sampling 24h after treatment. None of the orthovanadate doses caused a significant increase in the rates of micronuclei (MN). Since the results show that orthovanadate induced non-disjunction during male meiosis without an accompanying induction of MN in bone marrow erythrocytes under the present experimental conditions and doses, it is concluded that male germ cells (meiosis) are more sensitive to the aneugenic effects of orthovanadate than somatic cells (mitosis). However, induction of micronuclei was reported in the literature with orthovanadate, vanadylsulfate and ammonium metavanadate, which contradicts the notion that vanadium compounds might be unique germ cell aneugens.     

Earliest record of a parapithecid anthropoid from the Jebel Qatrani formation, Northern Egypt

A fifth anthropoid (= anthropoidean, simian or simiiform) genus and species from the late Eocene Fayum Quarry L-41, Abuqatrania basiodontos gen. et sp. nov., further augments the already remarkable primate diversity from this locality and provides the first convincing extension of the enigmatic family Parapithecidae into the oldest productive vertebrate fossil-bearing stratum of the Jebel Qatrani Formation. A. basiodontos exhibits no clear autapomorphies nor any apomorphies that are shared exclusively with any other parapithecid species, and it is most parsimoniously interpreted as the sister taxon of a Qatrania-Parapithecus-Apidium clade. Reevaluation of two contemporaries of A. basiodontos, Serapia and Arsinoea, suggests that neither genus should be ranked as a basal parapithecid. Serapia is more derived than primitive parapithecids in the morphology of the lower fourth premolar and exhibits greater overall similarity to Proteopithecus in cusp placement and the shape and proportions of its lower teeth; accordingly, we place Serapia in the family Proteopithecidae. Arsinoea is much more problematic and does not fit well with any hitherto known Afro-Arabian anthropoid group; we place this genus in a new anthropoid family, Arsinoeidae.     

The effect of ribose pre-treatment of cortical bone on γ-irradiation sterilization effectiveness

Reconstruction of large skeletal defects is a significant and challenging issue. Tissue banks often use γ-irradiation (15–35 kGy) to sterilize bone allografts, which, however, drastically impairs the post-yield mechanical properties. In previous studies, we reported the development of a method that protects human bone collagen connectivity through ribose crosslinking while still undergoing γ-irradiation. Given these promising results, the next step was to determine if the presence of ribose within the bone tissue would interfere with the effectiveness of the γ-irradiation sterilization against bacteria. This study had two stages. The aim of the first stage was to assess the protective effect of ribose in solution using a Bacillus pumilus spore strip model. The aim of the second stage was to assess the protective effect of ribose (R) on spores within a human cortical bone model in comparison to conventionally irradiated bone (I). Treatment of B. pumilus spore strips with ribose in solution led to temperature-dependent effects on spore viability versus spore strips treated with PBS alone. Ribose solution at 60 °C led to a notable two logs decrease in spore count relative to PBS at 60 °C. In the human bone model, the number of spores in the I and R groups were greatly decreased in comparison to the non-irradiated N group. No spore colonies were detected in the R group (n = 4) whereas two of the four plates of group I formed colonies. This study provides evidence that the method of pre-treating bone with ribose crosslinking prior to irradiation sterilization, while improving irradiation sterilized bone allograft quality, also may improve the effectiveness of the sterilization process.     

Effects of constitutive heterochromatin and genotype on frequency and distribution of chiasmata in the seven individual rye bivalents

Summary Number and distribution of chiasmata were studied in the single pair of homologous rye chromosomes in 29 chromosomal F₁ hybrids between the seven disomic wheat rye addition lines of Chinese Spring/ Imperial and five selected inbred genotypes of cultivated rye by using the differential Giemsa staining technique. The results indicate that the number and position of chiasmata is independent from the amount and position of C-heterochromatin. Genotype had an effect on chiasma number, whereas chiasma distribution within bivalents appeared to be determined by morphological features of chromosomes. Late replicating DNA in constitutive heterochromatin may delay the separation of half bivalents if chiasmata are formed between them and the centromere.Supported by Deutsche Forschungsgemeinschaft, Bonn     

A Neurosecretory Phenomenon in Some Cerebral Nervous Cells of the Land Snail

Some cerebral neurosecretory cells of the land snail Helix aspersa maxima have been studied using light microscopy combined with image analysis. The amount of neurosecretion varies during the course of the day, displaying a peak at 22:00 GMT. This peak is in phasis with the maxima of the locomotor and food-intake activities recorded by means of a video apparatus.