Individual strategies of human adaptation under extreme conditions

Starting from the investigations of Sechenov, Pavlov, and Uchtomsky, the Russian psychophysiological school has been considering adaptation in connection with the biological and social origin of the person (human as a rational being) as an integrated, coordinated, and self-controlled system. On the basis of the problem of man and the environment, Medvedev added to the theory of human adaptation the activity paradigm that enables us to uncover the distinctive features of occupational activities under various environment conditions. The theoretical and practical investigations based on the activity methodology presented the opportunity to find new principles of interaction between man and the environment and of the strategy of adaptive behavior. From the investigations one could see that the main characteristic of the human-environment interaction is that the active factor is the human who could simulate different adaptation strategies.     

Water balance and adaptation strategy in insects of Central Yakutia to extreme climatic conditions

Original experimental data describing the strategy for cold adaptation of the winter form of blackveined white Aporia crataegi L. living in Central Yakutia, a region with a harsh continental climate and long and very cold winters, are presented in comparison with other insects of Yakutia. Open wintering insects were shown to develop an efficient water-saving mechanism in a frozen state. This can be significant for their survival in post-diapause. Certain relationships between water balance, wintering mode, and strategy for cold adaptation have been revealed by the example of several insect species of this region in comparison with insects living in less severe climatic conditions.     

Structural stability of polypeptide nanofilms under extreme conditions

Self-assembly of designed peptides is a promising area of biomaterials research and development. Here, polypeptide nanofilms have been prepared by electrostatic layer-by-layer self-assembly (LBL) of cysteine (Cys)-containing 32mers designed to be oppositely charged at neutral pH, and structural stability of the films has been probed by subjecting them to various extreme physical and chemical conditions. The results suggest that although electrostatic attraction plays a key role in strengthening polypeptide films, stability is inversely related to absolute net charge of the supramolecular complex. This behavior is similar to the typical behavior of small globular proteins. Film structure is very stable in organic solvent and, when dehydrated, at extreme temperatures. Such stability is in marked contrast to the behavior of proteins, which tend to denature under comparable conditions. Similar to proteins, peptide nanofilms cross-linked by disulfide (S-S) bonds are considerably stronger than films stabilized by electrostatic, van der Waals, or hydrophobic interactions alone. This effect is particularly evident at extremes of pH and at elevated temperature when the film is hydrated. These results, the great variety of possible peptide structures, the inherent biocompatibility of l-amino acids, and current applications of thin films in commercial products together suggest that polypeptide films are promising for the development of new or enhanced products in food technology, drug delivery and medical device coatings, and biomaterials.     

Principles of membrane stability and phase behavior under extreme conditions

Biological membranes consist of a complex assortment of lipids and proteins. The arrangement of the components, particularly in regard to their lateral disposition in the plane of the membrane under physiological conditions, is dependent on the phase behavior of the different membrane lipids and the way that this behavior is modified by interaction with other membrane components and electrolytes in the aqueous medium. Irreversible phase separation of components within the membrane may result from exposure to extreme environmental conditions including temperature, pressure, or electrolyte concentration. The principles underlying the phase-mixing behavior of model membrane systems can be used to provide useful information about the factors that determine the stability of biomembranes under physiological and non-physiological conditions. These data are reviewed and used to predict events that take place when membranes are exposed to environmental stress.     

Life under extreme conditions: aspects of evolutionary adaptation to temperature in crustacean proteases

Summary The kinetic properties of a trypsin-like protease — based on cleavage of an artificial substrate — were investigated in several crustacean species from the Weddell Sea and compared to those obtained from species from tropical, temperate and subarctic regions. Decisive steps of thermal acclimation occurred in the lower temperature range, resulting in pronounced cold adaptation of the Antarctic benthic species; this becomes evident from lowered activation energies of the trypsin-like proteases and in comparatively high enzymic activities at 0°C. In contrast, species living at high ambient temperatures are more favoured by thermostability at higher temperatures rather than by a change of activation energy.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation     

Protein adaptation and biogeography: Threshold effects on molecular evolution

Protein adaptations to the physical environment play critical roles in determining the biogeographical distributions of species. The study of closely related species in habitats differing slightly in temperature or pressure offers an excellent experimental approach for discerning environmental thresholds of protein perturbation and the types of amino acid substitutions that are effective in maintaining optimal protein properties. These adaptations may involve amino acid replacements other than at the active site residues involved in catalysis or binding, a discovery with implications for the debate between adherents to the Neutralist and Selectionist points of view.     

Physical and molecular bases of protein thermal stability and cold adaptation

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Morphology and anatomy ofCaloplaca coralligera (Teloschistaceae) as adaptation to extreme environmental conditions in the maritime Antarctic

The anatomical and morphological structure of the lichenCaloplaca coralligera (Hue.)Zahlbr. was investigated in connection with mechanisms of colonization and adaptation to the special conditions of maritime Antarctic.Caloplaca coralligera seems to be endemic to the antarctic region. The lichen is unique in its morphology, growing like a crustose lichen with a prothallus, but the very thallus being composed of many vertical, frutescent branches not higher than large isidia. Due to fusions of the distal parts of the branches the morphology is characterized by air-filled cavities between the erect thallus parts where the phycobionts are located only close to the outermost surface. But also anatomically a system of air-filled cavities is developed by a net-like structure of hyphae. This may result in an insulation from temperature exchanges with the rocky substrate. It is speculated that this peculiar thallus structure might be advantageous to a lichen growing on compact substrates by buffering the diurnal temperature extremes which are characteristic for rocks under a strong radiation exchange with the atmospheric surrounding.Dedicated to Prof. DrO. L. Lange on the occasion of his retirement and of his 65th birthday.     

Molecular adaptation to an extreme environment: origin of the thermal stability of the pompeii worm collagen

The annelid Alvinella pompejana is probably the most heat-tolerant metazoan organism known. Previous results have shown that the level of thermal stability of its interstitial collagen is significantly greater than that of coastal annelids and of vent organisms, such as the vestimentiferan Riftia pachyptila, living in colder parts of the deep-sea hydrothermal environment. In order to investigate the molecular basis of this thermal behavior, we cloned and sequenced a large cDNA molecule coding the fibrillar collagen of Alvinella, including one half of the helical domain and the entire C-propeptide domain. For comparison, we also cloned the 3' part of the homologous cDNA from Riftia. Comparison of the corresponding helical domains of these two species, together with that of the previously sequenced domain of the coastal lugworm Arenicola marina, showed that the increase in proline content and in the number of stabilizing triplets correlate with the outstanding thermostability of the interstitial collagen of A. pompejana. Phylogenetic analysis showed that triple helical and the C-propeptide parts of the same collagen molecule evolve at different rates, in favor of an adaptive mechanism at the molecular level.     

The participation of the nontraditional neuromediator nitric oxide in the mechanisms of adaptation to extreme conditions]

The investigation was performed on the medial (MMS) and lateral (LMS) magnocellular subdivisions of the hypothalamic paraventricular nuclei (HPN). The histochemical activity NO synthesizing enzyme nitric oxide synthase or NOS whose histochemical marker is NADPH-diaphorase (NADPH-D), immunocytochemical content of oxytocin (OXY), vasopressin (VP) and nucleoli sizes (squares) were studied in the mature male rats under experimental reconstruction of the both micro- and macrogravity, which are factors of the gravity field changes acting to the body during the space flight. Two experimental effects were used: B--tail suspending (imitation of the microgravity effects), C--centrifugation at 2 G (imitation of the macrogravity effects). The effect durations were designed as a time period when body is mostly affected by (1 day) and adapted (15 days) to the stress. There were 6 animal groups. 1--B(15 days), 2--B(15 days) succeeded by C(1 day), 3--B(15 days) succeeded by C(15 days), 4--C(1 day), 5--C(15 days), 6--intact animals. The histochemically and immuno-cytochemically stained neurons developing the high, moderate and small reaction intensity were counted in serial HPN sections under the light microscope and the results obtained were transformed to percent neuron contents. The nucleoli squares were examined by using the TV analyser. The histochemical staining intensity of NADPH-D in MMS is enhanced in the animals of the groups 1-4; the number of NADPH-D staining neurons with high enzyme activity was increased in 8-14 times. In the animals of group 5 the NADPH-D activity did not differ from the intact animals. The number of MMS neurons with high OXY immunoreactivities was increased up to 1.5-1.7 times in groups 1-5 if compared to those of intact controls. VP-positive neurons of LMS developed the similar increase in number of the high staining neurons in experimental animals as well as OXY-positive neurons of MMS. The nucleoli enlargement was observed in MMS (in 1.3-1.5 times) of groups 1-5 (insignificantly in group 5) and in the most magnocellular neurons LMS (in 1.5-1.7 times) of group 2-5 except group 1 where nucleoli were insignificantly decreased. The nucleoli sizes of group 4 were more than group 5. So the hypothalamo-neurohypophyseal system was activated in the animals subjected of the earthly correlates of micro- and macrogravity. The data obtained suggest involvement both the nonconventional neurotransmitter NO and stress-related peptides OXY and VP in the mechanisms subserving adaptation to the extreme factors by what a human has to be faced with during the space flight.     

The blood system and the organism adaptation to extreme factor

The formation of blood system adoptive reaction in many cases is defined by the type of action and the condition of hemopoietic inductive microenvironment: hemodynamics of hemopoietic tissue, functional conditions of bone marrow macrophages, mast cells and glycosaminoglycans content. The shift in hemodlobin fraction occurs in extreme conditions requiring an increased gas transport by the blood. In case of tissue lesion, lymphocytes stimulate their regeneration. Morphogenetic function of lymphoid cells may be alerted by immunomodulators. Blood cells participate in angiogenesis, and this property may be used for vessel grafts production.     

Heliotropium thermophilum,an extreme heat tolerant species,promises plants about adaptation to high soil temperature conditions

To understand high temperature tolerance, Heliotropium thermophilum, a flowering plant thriving in a geothermal field with a soil temperature ranging between 55 and 65 °C, was grown in controlled laboratory conditions and two different soil temperatures were applied to the plants. One of them was the control group (CT 25 ± 3 °C) and the other was the high temperature group (HT 60 ± 4 °C). Water potential, dry weight, cell membrane injury (CMI), lipid peroxidation, hydrogen peroxide, chlorophylls, carotenoids, flavonoids, anthocyanins, proline and total soluble sugar contents were measured. Contents of total soluble sugars, phenolics, flavonoids, anthocyanins, proline were found to be higher in HT group than CT while CMI was opposite. Moreover, no difference was determined in water potential, dry weight, lipid peroxidation, total chlorophyll and carotenoids between CT and HT. H. thermophilum plants adapted to high temperature under laboratory conditions through changing membrane lipid saturation, accumulating osmotically active compounds to save water or increase its uptake and inducing antioxidants such as phenolic compounds to keep reactive oxygen species under control. In conclusion, this study showed that H. thermophilum plant was highly resistant to high soil temperature under optimized laboratory conditions. Moreover, a plant that can withstand 60 °C for a long period of time up to 60 days under laboratory conditions was reported for the first time.