Leaching: use of a thermophilic and chemoautotrophic microbe

A chemoautotrophic, thermophilic, and acidophilic microorganism capable of oxidizing reduced sulfur and iron compounds and leaching concentrates of molybdenite and chalcopyrite at 60 degrees C has been characterized by transmission and scanning electron microscopy. This constitutes the first direct observations of microorganisms on ore fines.     

High abrasion resistance with sparse mineralization: copper biomineral in worm jaws

Biominerals are widely exploited to harden or stiffen tissues in living organisms, with calcium-, silicon-, and iron-based minerals being most common. In notable contrast, the jaws of the marine bloodworm Glycera dibranchiata contain the copper-based biomineral atacamite [Cu2(OH)3Cl]. Polycrystalline fibers are oriented with the outer contour of the jaw. Using nanoindentation, we show that the mineral has a structural role and enhances hardness and stiffness. Despite the low degree of mineralization, bloodworm jaws exhibit an extraordinary resistance to abrasion, significantly exceeding that of vertebrate dentin and approaching that of tooth enamel.     

Predatory fish select for coordinated collective motion in virtual prey

Movement in animal groups is highly varied and ranges from seemingly disordered motion in swarms to coordinated aligned motion in flocks and schools. These social interactions are often thought to reduce risk from predators, despite a lack of direct evidence. We investigated risk-related selection for collective motion by allowing real predators (bluegill sunfish) to hunt mobile virtual prey. By fusing simulated and real animal behavior, we isolated predator effects while controlling for confounding factors. Prey with a tendency to be attracted toward, and to align direction of travel with, near neighbors tended to form mobile coordinated groups and were rarely attacked. These results demonstrate that collective motion could evolve as a response to predation, without prey being able to detect and respond to predators.     

Nitrogen Flows in Agrocenosis of Winter Wheat Under Conditions of Different Reactions of Typical Chernozem Medium (Based on Application of <Superscript>15</Superscript>N)

It is shown that an increase in winter wheat on typical chernozem characterized by the acid reaction of the soil medium leads to a decrease in grain yield to 30% and straw weight to 25%. The crop reached the maximum level after introducing urea and manure wastes (the yield gain was 199% in neutral soil and 165% in acidic soil). The improvement of plant nitrogen nutrition by introducing fertilizers led to an increase in the protein content in grain by 1.2 times on both soils; at the same time, the protein content was 1.1 times lower in acidic soil than in the neutral one. The maximum content of protein in winter wheat grain accumulated after both types of fertilizers were applied on neutral soil; the use of manure wastes alone decreased the protein content in grain. It has been revealed that a decrease in the yield of grain and a decrease in the content of crude protein in this grain after acidification of typical chernozem is due to a decrease in the amount of mineral nitrogen in soil and an increase in its gaseous losses. The pattern of nitrogen transformation in soil, as well as the availability of nitrogen for the plants, varied as the reaction of the medium changed. In acidic soil, the consumption of mineral fertilizer nitrogen and manure wastes by the plants decreased by 12–13% and the consumption of soil nitrogen decreased by 45%. The effect of wastes decreased the consumption of urea nitrogen by 49% (neutral soil) and by 69% (acidic soil). The consumption of fertilizer nitrogen by the plants decreased by 12–15% after acidifying typical chernozem and by 12–17% after immobilizing this type of chernozem and increased gaseous losses by 18–81%. It has been concluded that the agrophytocenosis of winter wheat maintains the ecological balance (homeostasis) when wastes from a pig-breeding complex are used and is exposed to stress when urea is applied in acid chernozem. Soil acidification decreased the resistance of agrophytocenosis to the level that is observed when manure wastes were applied and to adaptive depletion when urea was used.     

Alcohol drinking: abnormal intake caused by tetrahydropapaveroline in brain

Tetrahydropapaveroline (THP), a dopamine-dopaldehyde condensation product, was delivered directly into the cerebral ventricle of rats automatically every 15 minutes for 12 days. The animals were given access to both water and ethylalcohol, the latter being presented in 12 concentrations from 3 to 30 percent. Within 3 to 6 days of the start of the infusion of THP, the rats, which normally rejected alcohol, drank alcohol solutions in increasingly excessive amounts; this was accompanied by symptoms that were similar to those of withdrawal and intoxication. These results provide evidence that an abnormal metabolite in the brain may produce the addictive state caused by alcoholic beverages.     

Induction of cellular senescence in immortalized cells by human chromosome 1

The control of cellular senescence by specific human chromosomes was examined in interspecies cell hybrids between diploid human fibroblasts and an immortal, Syrian hamster cell line. Most such hybrids exhibited a limited life span comparable to that of the human fibroblasts, indicating that cellular senescence is dominant in these hybrids. Karyotypic analyses of the hybrid clones that did not senesce revealed that all these clones had lost both copies of human chromosome 1, whereas all other human chromosomes were observed in at least some of the immortal hybrids. The application of selective pressure for retention of human chromosome 1 to the cell hybrids resulted in an increased percentage of hybrids that senesced. Further, the introduction of a single copy of human chromosome 1 to the hamster cells by microcell fusion caused typical signs of cellular senescence. Transfer of chromosome 11 had no effect on the growth of the cells. These findings indicate that human chromosome 1 may participate in the control of cellular senescence and further support a genetic basis for cellular senescence.