Cytobios最新文献

A second function of carbonic anhydrase (CA) isoforms has already been proposed. This involves the dispersal of complexes in which six carbon dioxide molecules sequester a hydroxyl ion when the gas reacts with liquid water. The semi-catalytic reaction does not require the formation of bicarbonate as an essential corollary. This function is, therefore, a likely activity of carbonic anhydrase related proteins that have recently been discovered and which lack the active zinc site essential for the hydration of carbon dioxide. Re-examination of possible functions for the complex of six CO2 molecules with a hydroxyl anion have brought to light several circumstances where the presence of fully reversible complexes could have physiological advantages. A catalytic synthesis and dissolution of the complexes could thus be the important function for the carbonic anhydrase-related proteins (CA-RP) molecules as well as of some CA isoforms. The possible mechanisms for this extended second catalytic function and examples are briefly discussed.

Thirty-six accessions, representing the full complement of all the nine annual Cicer L. species, viz C. arietinum, C. reticulatum, C. echinospermum, C. pinnatifidum, C. judaicum, C. bijugum, C. chorassanicum, C. yamashitae and C. cuneatum, were subjected to karyotype analysis for the first time in a single comprehensive study. The detailed karyotype of C. chorassanicum was also investigated for the first time. A 12 h cold water pretreatment and 13 min 60 degrees C 1 N HCl hydrolysis confirmed a somatic chromosome number of 2n = 16 in all the species. Within species interchromosomal size variation was observed to be quite large in C. arietinum, C. reticulatum and C. echinospermum, but not in the remaining six species. Individual chromosome size ranged from 3.77 microns in C. echinospermum to 1.32 microns in C. arietinum while the haploid genome length ranged from 20.65 microns in C. echinospermum to 14.92 microns in C. cuneatum. Ample rearrangement of chromatin among chromosomes within a species was implied to have played a role in Cicer genome evolution. The nine species were classified in two groups based on karyotypic similarity, with the first group comprising the inter-crossable species C. arietinum, C. reticulatum and C. echinospermum, while the remaining species forming the second group. The first group species are also genetically close to each other as deduced by other morphological, biochemical and DNA based studies. Circumstantial evidence has lead to the speculation that perhaps karyotypic similarity and interspecific crossability are positively related to each other.

The vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) levels of 36 patients with adrenal gland tumours were analysed. The mean age of patients was 43 years (29-67 years), and there were 25 women (69.4%) and 11 men (31.6%). In 34 patients adrenalectomy was performed and in two cases lesions were considered inoperable. In all cases VEGF and bFGF were measured preoperatively and in all operated patients the level of VEGF was measured at 1 month postoperatively. A statistically significant increase in VEGF levels before surgery in comparison with the controls was recorded in all patients with adrenal tumours. No correlation between the size of a tumour and VEGF levels was observed. The serum level of VEGF decreased in patients after surgical removal of the tumour, no matter which type of tumour, with the exception of a patient showing a recurrence of cortex cancer. A statistically significant decrease was found only in patients operated on for cortex cancers and hormonally active and inactive cortex and medulla inactive benign tumours. The postoperative recurrence of the malignant tumour may be preceded by an increase in plasma VEGF levels. Such correlations were not found with bFGF.

Infection with Methorchis bilis was recognized for the first time in the residents of Novosibirsk area (Russia). During a serological survey (37 patients in toto), it was possible to demonstrate that 48.5% of the serum samples tested possessed antibodies to Opisthorchis felineus antigens, 37.8% to both Opisthorchis felineus and Methorchis bilis antigens, and 13.5% to Methorchis bilis antigens only.

Rabbit erythrocytes in methanolic phosphate medium were used to bioassay the activity of authentic samples of methyl stearate and methyl palmitate (in 10% methanol:90% water, v/v), which had been identified as apparent oceanic naturally occurring cytolins (APONIN-3 and -4) produced by Nannochloris oculata. The two natural products are notable for cytolytic activity toward the unarmoured dinoflagellate, Gymnodinium breve Davis, an organism responsible for red tides consisting of harmful algal blooms in the Gulf of Mexico and along the eastern coast of the United States. Bioassays were done with heparinized rabbit blood. The absorbance at 540 nm was observed for 15 min in comparison with a sample treated with haemolysing agent. The results indicated that at reasonable concentrations of 1-10 ppm, neither was a haemolysin, although such concentrations caused cytolysis of G. breve cultures.

Previous investigations in which metaphase plates of cells in rapid division were incubated in phosphate buffer at high temperature revealed numerous heterochromatic dots in chromosomes after Giemsa staining. In contrast, chromosomes from cells with a reduced capacity for reproduction were devoid of such dots, or the dots were sloughed-off into rings and patches of heterochromatin. In two types of cells which were rapidly dividing, namely HeLa cells (cervical cancer) and cells from regenerating planaria, phosphate incubation followed by Giemsa staining revealed an 'aura' or 'glowing' effect on the chromosomes, consisting of a densely staining core surrounded by a lightly stained periphery. This finding might be developed into a diagnostic test for certain malignancies, for cells undergoing dedifferentiation, or for tissues undergoing regeneration.

The activities of phosphatases and other biochemical parameters were examined in rats treated with isosaline leaf and stem-bark extracts of Harungana madagascariensis (L). Results show that both the leaf and stem-bark extracts significantly increased the activities of serum and liver alkaline phosphatase, liver acid phosphatase, liver and kidney glucose-6-phosphatase, fructose-1,6-diphosphatase and glycogen in the treated rats. While the stem-bark extract significantly elevated the activities of fructose-1,6-diphosphatase and glycogen in the kidney, these biochemical parameters were not affected by treatment with the leaf extract. The activity of serum acid phosphatase was unaffected by the two extracts. The results obtained clearly show that these extracts caused a marked increase in gluconeogenesis in the liver and kidney of the treated rats. While the stem-bark extract increased gluconeogenesis in both liver and kidney, the leaf extract caused an increase in gluconeogenesis only in the liver. The increased serum alkaline phosphatase activity caused by these extracts may, aside from having other tissues contributing to it, be due to damage caused by these extracts to the hepatocytes. The extent of pathological changes as well as the implications of these findings to folklore medicine requires further investigation.

The present experiments were conducted to test 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) accumulation in the tissues, and its influence on cell proliferation and steroid secretion. A dose of 3.2 ng of TCDD/g tissue was added at the beginning of the culture, and the media were changed every 24 h or not changed till the end (96 h) of the culture. TCDD in the tissue was analysed by mass spectrometry, and the percentage of proliferating cells was measured using the MIB-1 labelling index. TCDD added to the culture medium accumulated in the tissues after 24 h (59.3%) and 96 h (81.2%) of exposure. The accumulative effect of TCDD was manifested by a reduction in the percentage of proliferating cells (53.5 and 33.8%, after 24 and 96 h exposure, respectively). A single exposure to TCDD had no effect on progesterone, reduced testosterone secretion and caused a significant increase in oestradiol secretion. Prolonged exposure to TCDD caused an increase in the concentration of the three steroids investigated in the culture medium. The results suggest that TCDD action is complex in the follicles.

The relationship between the basic quantitative characteristics of the Q-heterochromatin (Q-HR) region variability of autosomes and of the Y chromosome in human populations was examined. A definite relationship between the mean number of Q-HR per individual, the distribution and frequencies of Q-HR on autosomes and the size of the Q-heterochromatin segment of the Y chromosome at the population level was shown to exist. The amount of autosomal Q-HR was lower in individuals with larger Q-heterochromatin segments on Y chromosomes, and vice versa. The hypothesis that the amount of chromosomal Q-HR in the genome of modern human populations may be under the control of natural selection, is discussed.

The karyotype of a male pigmy anteater, Cyclopes didactylus, an endangered species from the Amazon region, is described. The size and morphology of the X and Y chromosomes in mitotic and meiotic analyses is recorded and discussed.