Interrelationships between hydrogen-supplying reactions, respiration rate and extramitochondrial adenine nucleotide pattern

1. The influence of a diminished hydrogen supply on the regulation of oxidative phosphorylation of isolated rat liver mitochondria in dependence on the extramitochondrial (ATP)/(ADP) ratio was investigated. 2. The hydrogen supply was diminished by using various (beta-hydroxybutyrate)/(acetoacetate) ratios as a redox buffer and the results were compared with those of experiments using perifusion of immobilized mitochondria with non-saturating substrate concentrations. 3. In both experimental approaches the influence of a diminished hydrogen pressure on the maximum (ATP)/(ADP) ratio at minimum flux was low. An extreme decrease in the (beta-hydroxybutyrate)/(acetoacetate) ratio by more than two orders of magnetitude causes the (APT)/(ADP) ratio to decrease by about 50%. 4. The load capacity of oxidative phosphorylation (maximum flux) is considerably decreased by diminished hydrogen pressure. 5. The borderline cases of purely kinetic and thermodynamic limitations of hydrogen supply were calculated by computer simulation with respect to the regulating behaviour of oxidative phosphorylation and changes in the control strength of adenine nucleotide translocator and hydrogen supply in the overall reaction. 6. A prevalent thermodynamic influence of hydrogen supply on oxidative energy transformation in the cell is discussed in the light of experimental data.     

Molecular Co-occupancy Identifies Transcription Factor Binding Cooperativity In Vivo

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Der Feldbegriff in seiner Anwendung auf das Problem der Zellteilung

Summary The authors show that in certain isolated tissues (cornea of frog, mouse cancer) the mitotic processes continue during at least one hour. They are very strongly stimulated by heat and also by mitogenetic radiation. In the case of the cancer cells new mitoses are promoted in considerable number. A detailed analysis of both energy factors leads to the conclusion that they effect a disturbance of the unstable constellations (structures) of the elementary particles in the cell-body. Thus a certain degree of disorganisation of its plasma seems to stimulate cell-division. This statement is, in the opinion of the authors a proof that cell-division is controlled by a field, the trajectories of the elementary particles of the cell-body being a function of their coordinates relative to the cell-axes.

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Résumé Les auteurs démontrent que dans certains tissus survivants (la cornée des yeux de grenouille et le cancer de souris) les mitoses continuent leur processus d'évolution durant au moins une heure. Par l'application de chaleur aussi bien que par l'irradiation mitogénétique on peut accélérer beaucoup le rhythme des mitoses en cours d'évolution et provoquer (dans les cas de cancer seulement) l'apparition d'un nombre considérable de nouvelles mitoses. L'analyse de l'action de ces deux facteurs d'énergie aboutit à la conclusion qu'il ne peut s'agir que d'un dérangement des constellations instables des éléments du corps cellulaire. On peut en déduire qu'un certain degré de désorganisation du plasme est favorable aux divisions cellulaires. En poursuivant et en développant cette conception, les auteurs arrivent à la conception du champ cellulaire de division, définissant les trajectoires des particules élémentaires comme fonction de ses coordonnés relativement aux axes des cellules.

     

Selection of flowering forbs for conserving natural enemies in rice fields

The diversity of natural enemies harboured by flowering forbs on rice field bunds was recorded. Ageratum conozoides with a maximum Shannon diversity index of 1.8 followed by Acmella uliginosa, Eclipta alba and Tridax procumbens are amenable for ecological engineering, providing nectar, pollen and alternate prey to natural enemies.     

Loud calls of adult male red howling monkeys (Alouatta seniculus)

Loud calls of adult male red howlers (Alouatta seniculus) inhabiting a deciduous and semideciduous open woodland site in Venezuela were recorded opportunistically and categorized by ear and sonographically as barks and roars. Five to six different bark syllables were identified as occurring singly or in sequences of doublets and triplets. In barks, spectral energy was concentrated in bands at 350-400 Hz, 900-1,100 Hz, 1,800-2,200 Hz and 3,000-3,500 Hz, but not all higher bands were present in each syllable. Roars appeared sonographically like prolonged barks composed of a pulsated preface, a long legato climax and a brief, fractionated and at times pulsated coda; each part varied internally to the ear and in acoustic structure. All loud calls were of the noisy type (nonharmonic energy over a broad frequency range). Acoustic characteristics of the calls are interpreted in terms of the subserving vocal tract anatomy. I compare loud calls of red howlers with those of mantled (A. palliata) and black (A. caraya) howlers.     

Soil and root nutrient chemistry structure root-associated fungal assemblages in temperate forests

Root-associated fungi (RAF) link nutrient fluxes between soil and roots and thus play important roles in ecosystem functioning. To enhance our understanding of the factors that control RAF, we fitted statistical models to explain variation in RAF community structure using data from 150 temperate forest sites covering a broad range of environmental conditions and chemical root traits. We found that variation in RAF communities was related to both root traits (e.g., cations, carbohydrates, NO₃⁻) and soil properties (pH, cations, moisture, C/N). The identified drivers were the combined result of distinct response patterns of fungal taxa (determined at the rank of orders) to biotic and abiotic factors. Our results support that RAF community variation is related to evolutionary adaptedness of fungal lineages and consequently, drivers of RAF communities are context-dependent.