Analysis and Evaluation of the Functional State of the Cardiovascular System in Cosmonauts during Long-term Spaceflights

Forty-four cosmonauts participating in 28 main long-term (73–438 days) missions on the Mirorbital station performed functional tests with graded physical exercise using a bicycle ergometer. There were two types of this functional load. The cosmonauts that participated in the first eight main missions performed a two-step exercise with a total load power of 1150 W. In the remaining cosmonauts, the exercise was three-step, with a total power of 1350 W. The results obtained during the flight were compared with the results of the same tests performed before the flight, which served as control values for each cosmonaut. To estimate the load tolerance, the heart rate (HR), systolic blood pressure, stroke volume (SV), cardiac output (CO), and cardiac index were analyzed. The data were grouped according to the load, taking into account the type of blood circulation for each group before and during the flight. The ratio between different types of blood circulation was found to change during the flight. The responses to both types of exercises before the flight were less favorable in the cases of the hyperkinetic type of circulation. In these cases, the dominance of the chronotropic function of the heart determined the increase in CO. In the cases of the hypo- and eukinetic types of circulation, the response to the exercise was close to normotonic. In microgravity, irrespective of the circulation type and the exercise, the mechanism of the CO formation changed: the effect of HR was dominant, and there was no increase in SV. Insufficient venous return to the chambers of the heart is the main cause of the decreased response of SV to exercises during spaceflight.     

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.     

Inhibition of agrobacterial oncogene expression by means of antisense RNAs

Infection of plants by soil bacterium Agrobacterium tumefaciens induces tumors referred to as crown galls. Tumor development is determined by the introduction of agrobacterial genes governing phytohormone (auxin and cytokinin) production into the plant genome. The most important of these genes are iaaM and ipt. Development of transgenic plants inhibiting the expression of these genes allows a raise of varieties resistant to crown gall disease. For this purpose, single and double tobacco transformants with antisense copies of iaaM and ipt fused with single and double promoters for the 35S RNA of the cauliflower mosaic virus (CaMV 35S and CaMV 35SS) were obtained. Inoculation of transgenic plants harboring the antisense oncogene copies with virulent A. tumefaciens strains C58 (pTiC58) and A6 (pTiA6) revealed significant, but still incomplete, inhibition of these genes. Agrobacterium-mediated transformation of transgenic plants gave rise to weakened tumors, which varied in morphology and allowed regeneration of whole plants. Analysis of the inhibition of the iaaM and ipt expression in tumor cells demonstrated that the RNA interference strategy is promising for developing plant varieties resistant to agrobacterial infection.     

Harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters – state of knowledge and research needs

Cyanobacterial blooms have increased in freshwater ecosystems worldwide in the last century, mostly resulting from eutrophication and climate change. These blooms represent serious threats to environmental and human health because of the production of harmful metabolites, called cyanotoxins. Like many countries, Egypt has been plagued with cyanobacterial blooms in most water sources, including the Nile River, irrigation canals, lakes and fishponds. However, the data about cyanotoxins produced in these blooms are limited. Only two types of cyanotoxins, microcystins and cylindrospermopsin, have been identified and characterised, mainly from Microcystis and Cylindrospermopsis blooms. The data revealed the presence of microcystins in raw and treated drinking waters at concentrations (0.05–3.8 µg l^?1), exceeding the WHO limit (1 µg l^?1) in some drinking water treatment plants. In addition, Nile tilapia Oreochromis niloticus caught from ponds containing heavy cyanobacterial blooms have accumulated considerable amounts of cyanotoxins in their edible tissues. The data presented here could be the catalyst for the establishment of a monitoring and management programme for harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters. This review also elucidates the important research gaps and possible avenues for future research on cyanobacterial blooms and cyanotoxins in Egypt.