Domestication of cereal crops in the old world: in search of a new approach to solving old problem

N.I. Vavilov's theory of the centres of origin of cultivated plants is still as a methodological base for studying processes of domestication. This theory, along with archaeological, botanical, and molecular genetic data, helped to determine the most probable regions where the principal cultivated species were introduced into culture. The search for the mechanisms of origins of morphological changes in the course of domestication is one of evolutionary biology's oldest problems. Employing novd molecular biological data for solving this problem provides a key to the understanding of these mechanisms and helps to reconstruct a possible scenario of how the traits that distinguish domesticated plants from their wild relatives got involved into selection. It is hypothesized that distinct physiological and morphological differences important to ancient agrarians originated from quantitative and/or qualitative changes in the loci regulating the programmes of plant ontogeny. This hypothesis helps to reveal the mechanisms of origin of certain traits in the course of domestication, to study the connection between the direction of selection and how such traits are genetically controlled, and to outline particular ways for further detailed studies of the evolutionary aspect of domestication processes.     

Using new tools to solve an old problem: the evolution of endothermy in vertebrates

During the past 30 years, the evolution of endothermy has been a topic of keen interest to palaeontologists and evolutionary physiologists. While palaeontologists have found abundant Permian and Triassic fossils, suggesting important clues regarding the timing of origin of endothermy, physiologists have proposed several plausible hypotheses of how the metabolic elevation leading to endothermy could have occurred. More recently, molecular biologists have developed powerful tools to infer past adaptive processes, and gene expression mechanisms that describe the organization of genomes into phenotypes. Here, we argue that the evolution of endothermy could now be elucidated based on a joint, and perhaps unprecedented, effort of researchers from the fields of genomics, physiology and evolution.     

Metabolic control: a new solution to an old problem

The phenomenon whereby the presence of oxygen regulates the rate of glucose metabolism was first described by Louis Pasteur. A novel mechanism has now been discovered, involving the AMP-activated protein kinase cascade, that can account for the Pasteur effect in ischaemic heart muscle.     

Critical temperatures in lactating dairy cattle: A new approach to an old problem

Thermoregulatory reactions of lactating cows (33 Kg milk/day) have been measured in summer (T_g 25° – 39°C) and in winter (T_g 9, 5° – 24°C) at 3-hr intervals, during four 24-hr cycles. The animals maintained an almost continuous peripheral vasodilation throughout the experimental period. The upper ambient temperatures at which a dairy cow maintains homoeothermy were calculated for different metabolic rates. At the maintenance level a dry cow may maintain homoeothermy at up to 24°C without sweating and up to 40°C if sweating at 50% of the maximal sweating capacity. For a cow producing 30 kg milk/day, the respective figures were 12°C and 24°C respectively. These data indicate that the thermoregulatory capacity of the animals in the natural climate considerably expands the thermal comfort temperature range.

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Zusammenfassung Die wärmeregulatorischen Reaktionen milchgebender Kühe (33 kg Milch/Tag) wurden im Sommer (T_g 25° – 39°C) und im Winter (T_g 9, 5° – 24°C) in 3-Stunden Intervallen während 4 mal 24 Stunden periodisch gemessen. Die Tiere hatten eine beinahe kontinuierliche periphere Gefässerweiterung während der Versuchsperioden. Die obere Umgebungstemperatur, bei der Milchkühe homoiothermisch bleiben, wurde aus verschiedenen Stoffwechselraten berechnet. Auf dem Erhaltungsniveau kann eine trocken stehende Kuh die Homoiothermie bis 24°C ohne Schwitzen halten und bis auf 40°C bei Schwitzen bis 50% des maximalen Schwitzvermögens. Für eine Kuh, die 30 kg Milch/Tag leistet sind die entsprechenden Werte 12°C beziehungsweise 24°C. Diese Werte zeigen, dass das Wärmeregulationsvermögen der Tiere im natürlichen Klima den Wärmekomfort-Temperaturbereich erheblich ausdehnt.

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Resume On a mesuré l'aptitude de thermorégulation de vaches en lactation (33 kg de lait par jour) toutes les 3 heures durant 4 cycles de 24 heures et cela aussi bien en été (T_g 25° à 39°C) qu'en hiver (T_g 9, 5° à 24°C). Les animaux ont présenté une vasodilatation périphérique assez constante durant toute la période des essais. On a en outre calculé, en partant de différents taux de métabolisme, la température ambiante maximum pour laquelle une vache laitière peut maintenir son homéothermie. Pour une vache sèche, ce maximum est de 24°C sans transpirer et de 40°C si elle transpire le 50% de sa capacité maximum. Pour une vache donnant 30 kg de lait par jour, ces chiffres s'abaissent à 12°C dans le premier cas, à 24°C dans le second. Ces chiffres montrent que la capacité de thermorégulation du bétail bovin augmente considérablement l'amplitude de la zone de confort thermique en climat naturel.

     

Childlessness in old age--an anthropological approach to a current problem

The amount of aged and old aged people is increasing markedly in all industrialized nations as well as in many developing countries. Additionally to the increasing life expectancy, a trend towards voluntary childlessness is observable. This trend will not only result in a continuing change of the population structure, it will also result in several individual problems of the aged population caused by childlessness. In the present paper the possible effects of voluntary childlessness on quality of life during old age are discussed from an anthropological point of view.     

Neuromolecular computing: a new approach to human brain evolution

Evolutionary approaches in human cognitive neurobiology traditionally emphasize macroscopic structures. It may soon be possible to supplement these studies with models of human information-processing of the molecular level. Thin-film, simulation, fluorescence microscopy, and high-resolution X-ray crystallographic studies provide evidence for transiently organized neural membrane molecular systems with possible computational properties. This review article examines evidence for hydrophobic-mismatch molecular interactions within phospholipid microdomains of a neural membrane bilayer. It is proposed that these interactions are a massively parallel algorithm which can rapidly compute near-optimal solutions to complex cognitive and physiological problems. Coupling of microdomain activity to permenant ion movements at ligand-gated and voltage-gated channels permits the conversion of molecular computations into neuron frequency codes. Evidence for microdomain transport of proteins to specific locations within the bilayer suggests that neuromolecular computation may be under some genetic control and thus modifiable by natural selection. A possible experimental approach for examining evolutionary changes in neuromolecular computation is briefly discussed. Received: 2 October 1998 / Accepted in revised form: 19 March 1999     

Novel knowledge-based potentials for ligand docking: variational approach to the old problem

The variational approach of evaluation for knowledge-based potentials is considered for the first time. In this approach, the problem to derive knowledge-based potentials is solved as the optimization task in the multiparametric model of atom types, reference states and interaction cutoff radii. Using analogy to liquid state theory we offered four new reference states and derived corresponding knowledge-based potentials. The cutoff radii and atom types are optimized to minimize averaged root-mean square deviations (RMSD) of the ligand docked positions regarding to the experimentally determined poses. The number of atom types is varied on the developed atom type tree with 6 root (C, N, O, S, P and the halogen type) and 49 apical atom types. We showed a pronounced effect of atom type choice on docking accuracy and proved that splitting of elements C, N and O of the periodic system up to the 18 optimal atom types essentially improves docking accuracy.     

Insecticide resistance in malaria vectors: a new approach to an old subject

The application of biochemical and molecular biological techniques to the study of insecticide resistance has revolutionized our understanding of the underlying genetic basis of resistance. Using the examples of glutathione S-transferase and esterase-based metabolic insecticide resistance, three different routes via which increased insecticide detoxication can be achieved are elucidated. An understanding of these molecular pathways opens up new avenues for manipulating mosquito populations to restore insecticide susceptibility to the vectors.     

Early hominid brain evolution: a new look at old endocasts

Early hominid brain morphology is reassessed from endocasts of Australopithecus africanus and three species of Paranthropus, and new endocast reconstructions and cranial capacities are reported for four key specimens from the Paranthropus clade. The brain morphology of Australopithecus africanus appears more human like than that of Paranthropus in terms of overall frontal and temporal lobe shape. These new data do not support the proposal that increased encephalization is a shared feature between Paranthropus and early Homo. Our findings are consistent with the hypothesis that Australopithecus africanus could have been ancestral to Homo, and have implications for assessing the tempo and mode of early hominid neurological and cognitive evolution.     

Evolution of genome size: new approaches to an old problem

Eukaryotic genomes come in a wide variety of sizes. Haploid DNA contents (C values) range > 80,000-fold without an apparent correlation with either the complexity of the organism or the number of genes. This puzzling observation, the C-value paradox, has remained a mystery for almost half a century, despite much progress in the elucidation of the structure and function of genomes. Here I argue that new approaches focussing on the genetic mechanisms that generate genome-size differences could shed much light on the evolution of genome size.     

Biofilms: new ideas for an old problem

Microbial cells, under moist conditions, are able to adhere to surfaces and to form structured communities embedded in a matrix of extracellular polymeric substances (EPS). In industrial environments, biofilms can cause heat and mass transfer limitations whilst in medical facilities they can be a source of contamination and proliferation of infections. Biofilm formation is related to the pathogenicity of some bacterial strains and cells in biofilms are usually resistant to antimicrobials agents, which increases the interest in new and sound methods for their prevention and destruction.     

Predicting the height of fossil plant remains: an allometric approach to an old problem

Interspecific correlations between plant height and basal stem diameter (the allometry of height) and between stem length distal to where diameter is measured (the allometry of stem taper) were determined for a total of 265 species with self-supporting stems and for the shoots of five conifers and 15 angiosperm vine species. The allometric equations obtained for these data are proposed as a method to predict the heights of fossil plants for which basal stem diameters are either known or inferred, and to predict the missing lengths of fragmented stems based on the most proximal stem diameters observed.