MICROARCHITECTONICS OF FEMALE SHARPTOOTH CATFISH GONADS GROWN IN AN ARTIFICIAL ENVIRONMENT

The article presents the research results obtained by use of probiotic «Sporothermin» for the cultivation of females of African sharptooth catfish in an artificial environment. Sporothermin is a probiotic that is a mixture of Bacillus subtilis and Bacillus licheniformis, which provides an increase in the adaptive abilities of fish to the long-term action of various adverse factors, which is relevant when growing in an artificial environment. The histological structure of the gonads of female sharptooth catfish was analyzed using a research motorized universal microscope Axio Imager. M2 (Carl Zeiss, Germany). The results of our research have shown that in sharptooth catfish grown using the probiotic «Sporothermin», germ cells are observed, represented by oogonia and young oocytes of the protoplasmic growth period. Oocytes appear, that finished protoplasmic growth as well as oocytes that have completed trophoplasmic growth. At this stage, oocytes in the cytoplasm contain fat droplets that are part of the yolk grains, coloring from light yellow to orange with various shades. Female sharptooth catfish (Clarias gariepinus) of the control group, grown without the use of the probiotic «Sporothermin», have a violation of the synthesis of yolk granules, as well as edema of the follicular layer of the gonads, resorption of yolk grains and edema of the connective tissue egg-bearing plate, there is no striation of the radial layer, and deformation of the trophoplasmic oocyte is noted. In histological studies of the gonads of female sharptooth catfish, it was found that the use of the probiotic «Sporothermin» leads to a decrease in disorders in their microstructure, due to the strengthening of the membranes of the gonad cells.

Estimation of tool wear according to cutting forces during machining procedure

Purpose The main purpose of the study was to analyze the relationship between cutting forces and tool wear during turning of steel 30CrNiMo8. Design/methodology/approach It is very important to find the optimal machining conditions to increase the tool life and to improve product quality. Width of tool wear was measured by universal microscope. Findings During experimental procedure, one chip shape was obtained for the given machining parameters. Results showed negligible tool wear for the given experimental conditions. In other words, the tool wear is negligible for one chip shape. Originality/value To increase tool wear, there are different chip shapes.

Imaging sub-micron objects with light microscopy: Visualization of the T-4 bacteriophage

While light microscopy has been used to image sub-micron objects, numerous problems with diffraction-limitations often preclude extraction of useful information. Using conventional dark-field and phase contrast light microscopy coupled with image processing, we have studied the following objects: (a) polystyrene beads (88nm, 264nm, and 557mn); (b) frustules of the diatom, Pleurosigma angulatum, and the T-4 bacteriophage attached to its host, E. coli or free in the medium. Equivalent images of the same areas of polystyrene beads and T-4 bacteriophages were produced using transmission electron microscopy.For light microscopy, we used a Zeiss universal microscope. For phase contrast observations a 100X Neofluar objective (N.A.=1.3) was applied. With dark-field, a 100X planachromat objective (N.A.=1.25) in combination with an ultra-condenser (N.A.=1.25) was employed. An intermediate magnifier (Optivar) was available to conveniently give magnification settings of 1.25, 1.6, and 2.0. The image was projected onto the back focal plane of a film or television camera with a Carl Zeiss Jena 18X Compens ocular.

Karyotype analysis of ten accessions of Hausa potato in Nigeria

Plant species may be classified according to their karyotype features. Variation in chromosome features is believed to have accompanied evolutionary divergence of many plant and animal species. The cytological characteristics of crop species vary with geographical location of plants. Knowledge of the karyotype relationships can be explored for effective genetic and breeding studies, especially in crops like the Hausa potato (Solenostemon rotundifolius) that have not received adequate research attention. This paper reports the results of the karyotype analysis of ten accessions of the Hausa potato cultivated in some parts of Nigeria. The accessions were raised in plastic bowls containing vermiculite soil, from which root-tips were harvested for slide preparation and karyotyping. The conventional squashing in aceto-orcein of root tissues after heating was used. The tissues were photographed under Nikon Universal Microscope, equipped with an MC 100 camera. The chromosomes were then measured under x400 magnification using a micrometer. Results showed that all the accessions were diploid with somatic chromosome number of 2n = 2x = 64. The total length of long-arms ranged from 108.80 µm in accession Pankshin to 118.14 µm in accession NRCRI (1). The total length of short arms ranged from 81.88 µm – 89.34 µm. The total length of long plus short arms ranged from 199.88 µm - 200.06 µm. The mitotic phases varied with accessions. Similarly, the arm ratio, r-value, centromeric index, coefficient of variation, total form, intra-chromosomal index and inter-chromosomal index varied with the accessions. The accessions were grouped into four clusters: accessions Hong (1), Hong (2), Manchok and Gembu in cluster I; accessions Pankshin and Langtang in cluster II; accessions NRCRI (1) and NRCRI (2) in cluster III; accessions Bokkos (1) and Bokkos (2) in cluster IV. The principal component analysis showed that variation in the complement length and the centromeric position accounted for 99.997% of the total variation amongst the accessions. The study demonstrated that cytological differences exist in the Hausa potato. Some accessions showed close phylogenetic relationship, but others were distantly related. These differences could be explored for the improvement of the Hausa potato accessions cultivated in Nigeria.