Current status of the river buffalo (Bubalus bubalis L.) gene map.

Ninety-nine loci have been assigned to river buffalo chromosomes, 67 of which are coding genes and 32 of which are anonymous DNA segments (microsatellites). Sixty-seven assignments were based on cosegregation of cellular markers in somatic cell hybrids (synteny), whereas 39 were based on in situ hybridization of fixed metaphase chromosomes with labeled DNA probes. Seven loci were assigned by both methods. Of the 67 assignments in somatic cell hybrids, 38 were based on polymerase chain reaction (PCR), 11 on isozyme electrophoresis, 10 on restriction endonuclease digestion of DNA, 4 on immunofluorescence, and 4 on chromosomal identification. A genetic marker or syntenic group has been assigned to each arm of the five submetacentric buffalo chromosomes as well as to the 19 acrocentric autosomes, and the X and Y chromosomes. These same markers map to the 29 cattle autosomes and the X and Y chromosomes, and without exception, cattle markers map to the buffalo chromosome or chromosomal region predicted from chromosome banding similarity.

Mutagenicity of cidial (phenthoate). I: Effect on maternal and fetal somatic cells.

Cidial, an organophosphorous insecticide (also known as phenthoate), was tested for its genotoxic effect on both maternal and fetal cells. Cidial was administered at three different dose levels (53.5, 106.9, and 171 mg/kg) to pregnant mice on day 16 of gestation. Maternal bone marrow and embryonic liver cells were examined for chromosomal aberrations and cellular proliferation. Cidial was found to increase the percentage of cells with chromosomal aberrations in both mothers and fetuses. It also significantly inhibited the rate of mitotic activity of both maternal and fetal cells, with the inhibitory effect being more appreciable in fetal cells than in maternal cells. The data indicate that cidial, which is widely used in rural areas, is hazardous to both mothers and their transplacentally exposed babies.

Synteny mapping in river buffalo.

The cosegregation of ten coding loci has been investigated, in a panel of 37 somatic cell hybrids resulting from the fusion of a hamster cell line and river buffalo lymphocytes, by use of Southern hybridization technique. Five syntenic groups, TCRB-PGY3, ASS-ABL, FUCA1P-CRYG, MBP-YES1, and CGN1-ACTA1, previously assigned to cattle as U13, U16, U17, U28, and U29 respectively, were also found to be syntenic in buffalo. Based on the extensive syntenic conservation and banding homology between cattle and river buffalo, comparative mapping predicts the localization of these syntenic groups on river buffalo Chromosomes (Chrs) :BBU7, BBU12, BBU2q, BBU22, and BBU4q respectively as they have been previously localized on cattle Chrs BTA4, BTA11, BTA2, BTA24 & BTA28.

Chromosome aberrations in spermatogonia and sperm abnormalities in Curacron-treated mice.

Curacron is an organophosphorus pesticide widely used in cotton fields. In order to assay its mutagenic potential in mammalian germ cells chromosomal aberrations in spermatogonial cells and sperm abnormalities were examined in mice after Curacron treatment. For studying chromosomal aberrations mice were treated both acutely (single treatment) and subacutely (for 5 consecutive days) with 3 dose levels of Curacron, 12, 36 and 72 mg/kg. Curacron was found to produce a significant increase in structural chromosomal aberrations after acute and subacute treatments. This increase was dose-dependent. A dose-dependent inhibition in mitotic activity in spermatogonia was also found. For studying sperm abnormalities mice were treated for 5 consecutive days with 20, 40 and 60 mg/kg. Morphological sperm abnormalities increased significantly after treatment with Curacron. The increase was dose-dependent. An inhibition of 40.2% in sperm count and of 74.5% in sperm motility occurred after treatment with 60 mg/kg Curacron. These results show that Curacron has a damaging effect on spermatogonial cells as well as on sperm morphology.

In vivo evaluation of the genotoxic potential of curacron in somatic cells of mice.

Cytogenetic effects produced in somatic cells by Curacron, a phosphoric acid ester insecticide, were assessed in mice by three criteria: chromosome aberrations, sister chromatid exchange (SCE), and micronucleus induction. Curacron significantly increased the frequency of all three in an apparent dose-dependent manner. Curacron also inhibited the mitotic activity. The increased number of micronuclei is comparable to the increase in chromosome aberrations; the latter were mainly breaks. The frequency of SCE was considerably less than the frequencies of micronuclei and chromosome aberrations.

Chromosomal and biochemical studies on the effect of kat extract on laboratory rats.

Kat is being used extensively in many countries as a central nervous system stimulant. The effect of three doses of crude kat extract on chromosomal division and abnormalities in bone marrow, as well as on DNA, RNA, and total protein content in brain and liver was studied in laboratory rats in order to test the possible mutagenicity of the drug. Kat was given as a single subcutaneous injection at 0.05 (usage dose), 0.52 (intermediate dose), and 1.00 (sublethal dose) g/kg body weight. Animals were sacrificed at 6, 24, and 48 hr after treatment. Also, some animals were exposed subacutely for 5 consecutive days with sacrifice occurring 6 hr after the last injection. The mitotic index was reduced by all treatments, with the greatest effect occurring in the subacute treatment. Chromosomal abnormalities were induced by kat at all three doses, administered acutely or subacutely. The significant chromosomal aberrations were in the form of gaps, breaks, centromeric attenuations, and centric fusions. The concentration of DNA, RNA, and total protein in liver and brain decreased at all doses, with the greatest decrease occurring after subacute treatment. These findings suggest that kat has a profound effect on cell proliferation, on chromosomal abnormalities, and on DNA, RNA, and total protein synthesis.

Cytogenetic effect of two antimonial antibilharzial drugs: tartar emetic and bilharcid.

The effects of tartar emetic and bilharcid, two antimonial antibilharzial drugs, on the chromosomes of laboratory rats are studied. The drugs were administered intraperitoneally in three doses--clinical, intermediate, and maximum tolerated--both acutely (6, 24, and 48 hours) and subacutely. The two drugs produced the same types of chromosomal aberrations with tartar emetic, inducing a higher rate of incidence. No significant differences in the number of cells with chromosomal aberrations were generally observed among the 6, 24, and 48 hours of the acute treatment with both tartar emetic and bilharcid. The dose-response relationship was examined for both the acute and the subacute treatments. Whereas the acute treatment of tartar emetic showed a dose-dependent linear increase in the number of cells with chromosomal aberrations, the subacute treatment of tartar emetic and the acute and subacute treatments of bilharcid displayed their maximum effects at an intermediate dose.