Uncoupling effect of protonophoric and nonprotonophoric analogs of carbonyl cyanide phenylhydrazone on mitochondrial oxidative phosphorylation

Analogs of carbonyl cyanide phenylhydrazone providing no reaction with nucleophilic groups and lacking acidobasic properties, respectively, were synthesized for study of mechanism of uncoupling effect on oxidative phosphorylation. Their retention, influence on proton transport, abilities to SH--groups modify and to stimulate respiration in rat liver mitochondria, together with their physico-chemical properties, namely lipophilicity, acidobasicity and reactivity were characterized. The substitution of acidic hydrogen of the imino group resulted in the loss of both acidobasicity and uncoupling effect on oxidative phosphorylation. A decreased reactivity resulted from the substitutions of nitrile groups with the uncoupling activity remaining preserved.     

Variable Chlorophyll a Fluorescence and CO(2) Uptake in Water-Stressed White Spruce Seedlings

Regulation of photosynthetic activity can contribute to the prevention of photodamage in stress resistant plants during exposure to drought or low temperatures. Responses to increasing levels of water stress were examined in seedlings of the stress resistant forest conifer, white spruce (Picea glauca [Moench.] Voss). Some seedlings were grown under aseptic in vitro conditions and others in pots. In relatively resistant in vivo seedlings, photosynthetic activities changed slowly in response to increasing water stress. Highly sensitive in vitro seedlings responded to water deficits similarly to in vivo seedlings but over a much shorter time scale. Fluorescence, CO₂ exchange, and stomatal conductance data reported here suggest possible mechanisms for the regulation of photochemical activity in these plants.     

Effects of acid-base imbalance on pulmonary angiotensin-converting enzyme in vivo

The effects of acid-base balance disturbances on pulmonary endothelial angiotensin-converting enzyme (ACE) were studied in anesthetized mechanically ventilated rabbits. Enzyme function was estimated from [3H]benzoyl-Phe-Ala-Pro ([3H]BPAP) utilization under first-order reaction conditions during a single transpulmonary passage and expressed as 1) substrate metabolism (M), 2) Amax/Km (Amax being equal to the product of enzyme mass and the constant of product formation), and 3) (Amax/Km)/100 ml blood flow. When respiratory acidosis/alkalosis was produced by altering respiratory rate at constant airway pressure, substrate (BPAP) utilization varied proportionally to arterial pH and inversely proportionally to arterial PCO2 (PaCO2) (P less than 0.05). Percent BPAP metabolism (%M) ranged from 92 +/- 3 (respiratory alkalosis) to 85 +/- 3 (normal), 82 +/- 3 (respiratory acidosis), and 78 +/- 2% (severe respiratory acidosis). Amax/Km similarly decreased from 899 +/- 129 to 825 +/- 143, 601 +/- 74, and 450 +/- 34 ml/min, respectively, and (Amax/Km)/100 ml blood flow was reduced from 176 +/- 26 to 131 +/- 22, 111 +/- 12, and 97 +/- 5, respectively. However, when respiratory acidosis/alkalosis was produced by altering both respiratory rate and airway pressure, no changes were observed in either %M, Amax/Km or (Amax/Km)/100 ml blood flow. Similarly metabolic alkalosis or acidosis did not alter M, Amax/Km or (Amax/Km)/100 ml blood flow. These results indicate that pulmonary endothelial ACE function can be affected by acid-base disturbances, probably indirectly through changes in perfused microvascular surface area.     

RPM2, independently of its mitochondrial RNase P function, suppresses an ISP42 mutant defective in mitochondrial import and is essential for normal growth.

RPM2 is identified here as a high-copy suppressor of isp42-3, a temperature-sensitive mutant allele of the mitochondrial protein import channel component, Isp42p. RPM2 already has an established role as a protein component of yeast mitochondrial RNase P, a ribonucleoprotein enzyme required for the 5' processing of mitochondrial precursor tRNAs. A relationship between mitochondrial tRNA processing and protein import is not readily apparent, and, indeed, the two functions can be separated. Truncation mutants lacking detectable RNase P activity still suppress the isp42-3 growth defect. Moreover, RPM2 is required for normal fermentative yeast growth, even though mitochondrial RNase P activity is not. The portion of RPM2 required for normal growth and suppression of isp42-3 is the same. We conclude that RPM2 is a multifunctional gene. We find Rpm2p to be a soluble protein of the mitochondrial matrix and discuss models to explain its suppression of isp42-3.     

Computer analysis of living cells: movements of the chromatoid body in early spermatids compared with its ultrastructure in snap-frozen preparations

 Quantitative analyses of cytoplasmic and nuclear organelle movements in living interphase cells at defined stages of differentiation are few. By phase contrast videomicroscopy and digital imaging techniques, we have traced the path of the chromatoid body (CB) and analysed its rapidly changing positions in relation to the nuclear envelope, Golgi complex and nuclear pale chromatin areas in living early spermatids of the rat. The CB had intimate interactions with the nuclear envelope and moved both in parallel and perpendicular fashion in relation to it. It had successive short contacts with the Golgi complex and nuclear pale chromatin areas. It was also seen to scan between two pale chromatin areas and it had pinocytosis-like transient engulfments during interactions with the pale chromatin. In ultrastructural analysis of snap-frozen preparations, the CB had a large contact area with the nuclear envelope with several intermediate organelles that may be involved in nucleocytoplasmic material transport. It is evident that quantitative image analysis of living cells is a powerful guide for ultrastructural analyses. The snap-freezing technique gives new possibilities for studies of structures that are sensitive to conventional fixation procedures. Accepted: 23 January 1997     

Fish stock assessments in Lake Konnevesi

In 1977, the average fish yield in the oligotrophic and oligohumic lake Konnevesi was 6.4 kg ha^–1 (2.6 kg vendace, 1.3 kg perch, 0.7 kg whitefish, 0.5 kg roach, 0.3 kg pike and 0.3 kg burbot). In that year the stock of vendace was exceptionally poor. A study was made to determine the optimum strategy for exploiting the stocks. The field work included test fishing (1970–78), sampling of catches (1977–80) and collection of catch per unit effort data (1978–80), and catch statistics (1969, 1970, 1977). The stocks were assessed by the Beverton and Holt method. Whitefish is exploited at a proper level. Fishing of vendace and roach can be increased, and the yield of pike would be greater, if the recruiting age were higher than at present.     

über die Natur der deuterenkephalen Leistung in der embryonalen Induktion

Zusammenfassung Jungen Gastrulen oder Epidermisexplantaten von Trituras wurde simultan Leber- und Knochenmarkgewebe des Meerschweinchens implantiert. Es war bekannt, da\ das erstgenannte Gewebe ausschlie\lich kephale, das letztere wiederum hauptsächlich mesodermale Gebilde induzierte. Auf Grund der Resultate wurde eine Schema des die Normogenese steuernden Induktionssystems ausgearbeitet, nach welchem die Regionalität des Keimes von zwei Induktionsfaktoren (N undM) bewirkt würde. Diese Faktoren sollen auf der Dorsalseite des Keimes Wirkungsfelder bilden, die einander teils überschneiden und als Gradienten in verschiedener Richtung schwächer werden.Das genannte, anfänglich als Arbeitshypothese bestimmte Schema wurde später kontrolliert, indem als Induktoren rein archenkephal induzierende, wärmebehandelte HeLa-Zellen sowie nichtvorbehandelte HeLa-Zellen, die sowohlN- wieM-Faktor enthielten, benutzt wurden. Diese Zellen wurden entweder für sich als Induktoren benutzt, oder sie wurden in verschiedenem Verhältnis miteinander vermischt. Die Resultate zeigten, da\ die im Induktor enthaltene unterschiedliche Quantität desM-Faktors das Zentralnervensystem dazu bestimmt, sich zu Deuterenkephalon oder Neuralrohr zu entwickeln, während wiederum bei fehlendemM-Paktor die Leistung rein archenkephal ist.Bei den Versuchen wurden Epidermisexplantate 24 Std lang neuralisiert oder mesodermalisiert und danach disaggregiert. Durch Reaggregation der Zellen zweier auf verschiedene Weise induzierter Blasen konnte ein Explantat zustande gebracht werden, in dem sich Deuterenkephalon und Ohrblasen entwickelten, die keiner der beiden Induktoren allein hervorzurufen vermöchte. Die Resultate wurden so gedeutet, da\ derN- und derM-Faktor primär die Zellen zur Differenzierung in neuraler bzw. mesodermaler Richtung determiniert. Die verschiedene Regionalität des Zentralnervensystems würde später durch die Einwirkung einer Interaktion zwischen den inM- und N-Richtung determinierten Zellen bestimmt, wobei die Natur der Regionalität von einem bestimmten quantitativen Verhältnis derN- undM-Zellen abhängig wäre.Verschiedene Hypothesen, die zur Deutung der Primärinduktion vorgebracht worden sind, werden diskutiert sowie ferner auch die Ergebnisse, in denen der Masseneffekt und die Spätinteraktion zwischen Zellen und Geweben behandelt wird.Zum Andenken an den am 9. 11. 62 gestorbenen Prof. Dr.Hermann Bautzmann, den berühmten Vertreter der entwicklungsmechanischen Schule vonSpemann, gewidmet. — Die Untersuchungen sind von der Sigrid Juselius-Stiftung und von The National Cancer Institute, National Institutes of Health, Public Health Service (C-5347) finanziell unterstützt worden.     

Bioreactor studies on hairy root cultures of Catharanthus roseus: Comparison of three bioreactor types

Summary Hairy roots of Catharanthus roseus were cultivated in three different types of bioreactors. The best growth and indole alkaloid production was achieved in an airsparged bioreactor with no other mixing. In the stirred bioreactor or in the bioreactor with medium circulation the roots did not grow, suggesting that hairy roots of C. roseus are more sensitive to stress than root cultures of many other plant species.     

<Emphasis Type="Italic">Methylophilaceae</Emphasis> and <Emphasis Type="Italic">Hyphomicrobium</Emphasis> as target taxonomic groups in monitoring the function of methanol-fed denitrification biofilters in municipal wastewater treatment plants

Molecular monitoring of bacterial communities can explain and predict the stability of bioprocesses in varying physicochemical conditions. To study methanol-fed denitrification biofilters of municipal wastewater treatment plants, bacterial communities of two full-scale biofilters were compared through fingerprinting and sequencing of the 16S rRNA genes. Additionally, 16S rRNA gene fingerprinting was used for 10-week temporal monitoring of the bacterial community in one of the biofilters. Combining the data with previous study results, the family Methylophilaceae and genus Hyphomicrobium were determined as suitable target groups for monitoring. An increase in the relative abundance of Hyphomicrobium-related biomarkers occurred simultaneously with increases in water flow, NO _x ^? load, and methanol addition, as well as a higher denitrification rate, although the dominating biomarkers linked to Methylophilaceae showed an opposite pattern. The results indicate that during increased loading, stability of the bioprocess is maintained by selection of more efficient denitrifier populations, and this progress can be analyzed using simple molecular fingerprinting.