Effect of age of cell donors of nuclei on effectivness of developing cloned rabbit embryos]

We studied the capacity of nuclei of rabbit fibroblasts taken from various developmental stages for reprogramming in the cytoplasm of mature aging enucleated oocytes and development of the cloned embryos to the preimplantation stages. A negative correlation was found between the age of an animal--donor of fibroblasts and efficiency of the development of cloned embryos (rmorula-blastocyst = -0.826, rblastocyst = -0.7139). A reliably decreased capacity for reprogramming of the nuclei of donor fibroblasts was shown upon transition from prenatal development to the postnatal one, as well as a trend to a decreased capacity of nuclei for reprogramming during aging. Aging of cells in the culture, at least until the 10th passage, did not affect the capacity of the nuclei of fetal fibroblasts for reprogramming and development of cloned embryos.     

Methyl Jasmonate Increases the Tropane Alkaloid Scopolamine and Reduces Natural Herbivory in Brugmansia suaveolens: Is Scopolamine Responsible for Plant Resistance?

The tropane alkaloid (TA) scopolamine is suggested to protect Brugmansia suaveolens (Solanaceae) against herbivorous insects. To test this prediction in a natural environment, scopolamine was induced by methyl jasmonate (MJ) in potted plants which were left 10?days in the field. MJ-treated plants increased their scopolamine concentration in leaves and herbivory decreased. These findings suggest a cause?Ceffect relationship. However, experiments in laboratory showed that scopolamine affect differently the performance of the specialist larvae of the ithomiine butterfly Placidina euryanassa (C. Felder & R. Felder) and the generalist fall armyworm Spodoptera frugiperda (J. E. Smith): the specialist that sequester this TA from B. suaveolens leaves was not negatively affected, but the generalist was. Therefore, scopolamine probably acts only against insects that are not adapted to TAs. Other compounds that are MJ elicited may also play a role in plant resistance against herbivory by generalist and specialist insects, and deserve future investigations.     

Age-Related Effect of Cells as Donors of Nuclei: On the Efficiency of the Development of Cloned Rabbit Embryos

We studied the capacity of the nuclei of rabbit fibroblasts taken from various developmental stages for reprogramming in the cytoplasm of mature aging enucleated oocytes and the development of the cloned embryos to the preimplantation stages. A negative correlation was found between the age of an animal donor of fibroblasts and the efficiency of the development of cloned embryos (r _{morula-blastocyst}= –0.826, r _blastocyst= –0.7139). A reliably decreased capacity for reprogramming of the nuclei of donor fibroblasts was shown upon the transition from prenatal development to postnatal development, as well as a trend to a decreased capacity of nuclei for reprogramming during aging. The aging of cells in the culture, at least until the tenth passage, did not affect the capacity of the nuclei of fetal fibroblasts for reprogramming and the development of cloned embryos.     

Production of cloned bovine embryos by somatic cell transfer into enucleated zona-free oocytes

Cloned bovine embryos were produced at the blastocyst stage. Prior to enucleation, oocytes were freed from the zona pellucida. Fibroblasts isolated from the bovine fetus were used as nuclear donors. Pairs of fetal fibroblasts and enucleated oocytes (cytoplasts) were glued in phytohemagglutinin solution under a binocular microscope. The subsequent electrofusion of 39 fetal fibroblast-cytoplast pairs yielded 36 reconstructed one-cell embryos (92.3%). After culturing in synthetic oviduct fluid for 7.5 days, seven cloned embryos developed to the blastocyst stage (19.4%) and six blastocysts were considered fit for transplantation. The applied technique of bovine embryo growth allowed 31.1% zona-free oocytes parthenogenetically activated by to reach the blastocyst stage.     

Cyanotoxins in small artificial dams in Kenya utilised for cage fish farming – a threat to local people?

Nine small artificial dams located in different climatic regions of Kenya were studied. The local communities use the stored water for various purposes, such as irrigation, domestic use, watering of livestock and cage fish farming. Such intense use is commonly accompanied by eutrophication, including fast growth of cyanobacteria, which at times produce cyanotoxins threatening human and animal life. We studied the pelagic community, analysed abiotic variables and identified microcystins by means of high performance liquid chromatography and ELISA kits at monthly intervals over a period of one year. Mass spectrometry (MALDI-TOF MS) was used to identify structural variants of microcystins by their protonated masses (M + H). Three dams contained microcystins, with the highly toxic Microcystin-LR being identified as the most prominent substance. Cell content of the toxin varied from 7.2 to 686.7 fg cell^?1. Basic limnological variables that indicate the probability of toxin presence were also recorded. Non-parametric Mann–Whitney U-test revealed significant differences in soluble reactive phosphorous, nitrate-N, water depth, total hardness and post-Nauplii stages sampled between toxin-producing and non-toxin-producing dams. Although most of the samples did not contain high amounts of cyanobacteria, the cyanotoxin-problem was evident, suggesting the need for regular cyanotoxin monitoring programs.     

Structure of Ecologo-Climatic Niches of <Emphasis Type="Italic">Poa palustris</Emphasis> L. and <Emphasis Type="Italic">P. nemoralis</Emphasis> L. (Роасеае) in Asian Russia

In addition to a specific morphotype, each species has a unique ecologo-climatic niche and a geographical area. The study of ecologo-climatic and geographical divergence may significantly contribute to the comprehension of species genesis and amount. The aim of this work is to compare ecologo-climatic niches of Poa palustris L., P. nemoralis L., and populations combining the features of both species (assigned in this work to the hybridogenic complex of P. intricata Wien), as well as reveal their identity. As a result of these researches, the areas of the both species were verified. The ecologo-climatic niches were determined with the use of GIS technologies and on the basis of their coordinates. Then potential areas of species—the regions where climatic conditions are favorable for their growth—were determined on the basis of six independent bioclimatic variables. A comparison of the ecologo-climatic niches calculated by MaxEnt software has shown that their distinctions are statistically significant.     

Aflatoxicosis in rabbits: Effectiveness of Egyptian raw bentonite in prevention or diminution the detrimental effects of naturally aflatoxin contaminated diets

Thirty five females and 15 males of New Zealand White mature rabbits about 6 months of age, were assigned to 1–5 dietary treatments (7 does+3 bucks for each): uncontaminated control diet, naturally aflatoxin contaminated diet without or with 1,2 and 3% bentonite. Rabbit fed with the aflatoxin-diet had a decreased (P<0.01 or 0.05) physical semen characteristics of bucks and a reproductive performance traits of does. The values of conception rate (%), gestation length (days), litter size (n) and litter weights (g) at birth and viability (%) of litters of doe rabbits, fed with the aflatoxin-diet, recorded, respectively: 64.5; 31.0; 4.4; 275.0 and 57.1 versus 85.6; 30.3; 7.9; 508.0; and 100 for those fed with the uncontaminated diet. Addition of bentonite to the aflatoxin contaminated diet improved in general the physical semen characteristics of buck and reproductive performance traits of doe rabbits. The results of the study demonstrate that adding 1% of Egyptian raw bentonite to the naturally aflatoxin contaminated rabbit diets can provide an effective, cheap and safe practical technique for preventing the aflatoxicosis in mature rabbits.     

A study of factors affecting the efficiency of electrofusion of enucleated eggs and cell-donors of nuclei

We studied the capacity of rabbit oocytes for electrofusion with morula blastomeres and fetal fibroblasts. The morula blastomeres fused with aging ooplasts more readily than the fetal fibroblasts: 92.9 versus 63.0%, p < 0.001. The fetal fibroblasts fused with young enucleated oocytes more efficiently than with the aging ones: 98.4 versus 63.0%, p < 0.001. Serum starvation of the fetal fibroblasts in DMEM medium for 7-14 days reduced their capacity for fusion with young ooplasts, as compared to that after starvation for 0-4 days: 67.2 versus 98.9%, p < 0.01). The increased time of "starvation" in an "impoverished" medium reduced the capacity of fetal fibroblasts with aging ooplasts as compared to the fibroblasts cultivated in the full medium and in the "impoverished" medium for one or two days: 64.5 versus 37.4%, p < 0.01. Hence, the efficiency of the fusion of the oocytes with nuclear donor cells depends on the age of the recipient oocyte, the origin of nuclear donor cells, and the conditions of cultivation.