Combined reaction of the lymphoid organs and the adrenals to stress in mature animals subjected to cold in the early period of postnatal ontogeny

Structural-functional organization of the lymphoid organs and functional state of the adrenals have been studied in animals, subjected to cold in early postnatal period, as well as changes of the parameters mentioned to a short and prolonged cooling in mature rats. For the animals increase in the thymus mass and in reproduction rate of lymphocytes in the thymus, spleen and lymph nodes is specific against the background of high corticosteroid secretion. When the control animals are kept in cold for a long time, after the phase of an acute stress, accompanied with hypercorticism and a pronounced lymphatic effect, during the period of an increased cold stability, the high secretion of glucocorticoid hormones is accompanied with a certain activation of thymus-dependent zones in the peripheral lymphoid organs. In the mature rats, subjected to cold at early ontogenesis both stress-reaction to cooling and rearrangement in the regulatory systems studied does not develop at adaptation to cold.     

RNA approaches the B‐form in stacked single strand dinucleotide contexts

Duplex RNA adopts an A‐form structure, while duplex DNA interconverts between the A‐ and B‐forms depending on the environment. The C2′‐endo sugar pucker seen in B‐form DNA can occur infrequently in ribose sugars as well, but RNA is not understood to assume B‐form conformations. Through analysis of over 45,000 stacked single strand dinucleotide (SSD) crystal structure conformations, this study demonstrates that RNA is capable of adopting a wide conformational range between the canonical A‐ and B‐forms at the localized SSD level, including many B‐form‐like conformations. It does so through C2′‐endo ribose conformations in one or both nucleotides, and B‐form‐like neighboring base stacking patterns. As chemical reactions on nucleic acids involve localized changes in chemical bonds, the understanding of how enzymes distinguish between DNA and RNA nucleotides is altered by the energetic accessibility of these rare B‐form‐like RNA SSD conformations. The existence of these conformations also has direct implications in parametrization of molecular mechanics energy functions used extensively to model nucleic acid behavior., 2016. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 65–82, 2016     

Analysis of plastid DNA-like sequences within the nuclear genomes of higher plants

A wide-ranging examination of plastid (pt)DNA sequence homologies within higher plant nuclear genomes (promiscuous DNA) was undertaken. Digestion with methylation-sensitive restriction enzymes and Southern analysis was used to distinguish plastid and nuclear DNA in order to assess the extent of variability of promiscuous sequences within and between plant species. Some species, such as Gossypium hirsutum (cotton), Nicotiana tabacum (tobacco), and Chenopodium quinoa, showed homogenity of these sequences, while intraspecific sequence variation was observed among different cultivars of Pisum sativum (pea), Hordeum vulgare (barley), and Triticum aestivum (wheat). Hypervariability of plastid sequence homologies was identified in the nuclear genomes of Spinacea oleracea (spinach) and Beta vulgaris (beet), in which individual plants were shown to possess a unique spectrum of nuclear sequences with ptDNA homology. This hypervariability apparently extended to somatic variation in B. vulgaris. No sequences with ptDNA homology were identified by this method in the nuclear genome of Arabidopsis thaliana.      

Incidence and levels of fumonisin contamination in Colombian corn and corn products

A survey was conducted to determine the levels of fumonisins B1 and B2 in corn and corn-based products available in Colombia for human and animal consumption. A total of 120 samples were analyzed by acetonitrile-water extraction, cleanup with a strong-anion-exchange column, and liquid chromatography with o-phthaldialdehyde-2-mercaptoethanol derivatization and fluorescence detection. The samples of corn and corn-based products for animal intake were taken at different feed manufacturing plants, whereas the samples used for human foods where purchased from local retail stores. The number of positive samples for fumonisin B1 was 20.0% higher in corn and corn-based products for animal intake (75.0%) than in corn and corn-based products for human consumption (55.0%). The levels of fumonisin B1 were also higher in corn and corn-based products for animal intake (mean = 694 μg/kg; range = 32–2964 μg/kg), than in corn and corn-based products for human intake (mean = 218 μg/kg; range = 24–2170 μg/ kg). The incidence and levels of fumonisin B2 were lower than those for fumonisin B1. Corn and corn-based products for animal consumption had an incidence of fumonisin B2 of 58.3%, with a mean value of 283 μg/kg, and a range of 44–987 μg/kg. The incidence of fumonisin B2 in corn-based products for human intake was 35.0%, with a mean value of 118 μg/kg and a range of 21–833 μg/kg. The highest incidence and levels of fumonisins were found in samples of hominy feed, with concentrations ranging from 86 to 2964 μg/kg fumonisin B1 and 57 to 987 μg/kg fumonisin B2.     

Dynamics of indices of the rat endocrine and lymphatic systems during cold adaptation

A study was made of the content of corticosterone, thyroxine and triiodothyronine in the blood, of the thymic weight and cytomorphological characteristics of rat lymph nodes during prolonged cold (4-5 degrees C) adaptation. Interrelated alterations in the characteristics under study were revealed at different stages of adaptation. The morphofunctional recovery of the lymphoid tissue occurs in the phase of the increased specific stability in spite of the fact that the action of cold is continued and the blood corticosterone concentration is elevated. A new type of the endocrine-lymphoid relationships is supposed to be formed during lengthy adaptation, with this type being different from that both in the starting state and acute stress.     

Nutritional Status in the Experiment with 105-Day Isolation as the First Phase of the Mars-500 Project

In a 105-day experiment simulating crew life in a interplanetary spaceship, shifts in the nutritional status were assessed in six volunteersthat differed in the body weight index, basal metabolic rate, attitude to the proposed diet, physical exercise, and workload. The results of the investigation showed that hard physical work under the conditions of the experiment led to the formation of the nutritional status against the background of more intensive basal metabolism, elevated metabolism of carbohydrates and lipids, and their increased mobilization from fat depot. Food ration, though it was sufficient to sustain health and fairly high calorie, did not fully meet individual taste preferences of some crewmembers and energy needs for physical activities. Under these conditions, heavy workloads required mobilization of lipids from fat depot and reducedthe hepatic detoxification and metabolic capacities. Self-limitation of eating protein-rich desserts led to a relative deficiency of protein intake. These changes in the diet were the reason why four out of six test subjects reduced their basal metabolism and lost body mass. The recovery of metabolism and slowdown of the body weight loss were achieved under these conditions by supplementing meals with digestible proteincontaining products.