Effects of experimentally altered glutathione levels on life span, metabolic rate, superoxide dismutase, catalase and inorganic peroxides in the adult housefly, Musca domestica

Effects of varied levels of glutathione, an intracellular redox buffer, were examined in the adult male housefly in order to study the inter-relationship between enzymic and non-enzymic antioxidant defenses. An increase of over 100% in the concentrations of glutathione was induced by the administration of 3 mM L-2-oxothiazolidine-4-carboxylate (LOC), which increases the intracellular level of cysteine. A decrease in glutathione concentration of up to 85% was achieved by the administration of L-buthionine-SR-sulfoximine (BUS), which irreversibly inhibits glutamylcysteine synthetase. Life spans of houseflies were shortened by a decrease in the glutathione concentration, but were not prolonged by augmentation of glutathione. Metabolic rate and superoxide dismutase activity were independent of glutathione concentration. H2O2 was increased by both experimental regimes, whereas catalase activity was decreased by BUS. Results suggest that catalase activity is influenced by glutathione concentration.     

Comparison of fiber types in skeletal muscles from ten animal species based on sensitivity of the myofibrillar actomyosin ATPase to acid or copper

Summary Comparisons were made of the histochemical characteristics of skeletal muscle from 10 animal species. The basic comparison was made from the staining patterns for the myofibrillar actomyosin ATPase produced by preincubation of fresh frozen cross-sections of muscle at alkaline pH (10.30) or acid pH (4.60) with those produced by preincubation in media containing Cu²⁺ at alkaline pH (10.30), near neutral pH (7.40), or acid pH (4.60). Muscle sections were also stained for reduced nicotinamide adenine dinucleotide tetrazolium reductase and alpha-glycerophosphate dehydrogenase to provide an indication of the relative oxidative and glycolytic capacity of the different fiber types. Type II fibers in mixed fibered muscles were either very sensitive, moderately sensitive, or relatively insensitive to inactivation of the myofibrillar actomyosin ATPase after acid preincubation. These fibers were identified as type IIA1, IIA2, and IIA3, respectively. The myofibrillar actomyosin ATPase of the type I fibers of these muscles, with the exception of those in mouse muscle, was activated by pretreatment with acid. A separation of animal species was possible based on the stability of the IIA1 fibers to inclusion of Cu²⁺ in the preincubation medium. For one group of animals (rat, mouse, monkey, man, dog, rabbit, and cow), a reciprocal relationship existed between lability to acid and stability to Cu²⁺ for type IIA1 and IIA3 fibers, respectively. For the second group of animals (horse, ass, and cat) there was a parallel relationship between lability or stability of the type IIA1 and IIA3 fibers to pretreatment with either acid or Cu²⁺ Visiting scholar from the Laboratory of Biomechanics and Physiology, College of General Education, Yamaguchi University, Yamaguchi 753, JapanSupported in part by Washington State Equine Research Program grant #105 3925 0042     

Mapping of brain activity in mesencephalic and diencephalic structures of toads during presentation of visual key stimuli: a computer assisted analysis of (14C)2DG autoradiographs

Summary The (¹⁴C)2DG autoradiographic technique has been employed to quantitatively map glucose utilization in the mesencephalon, the diencephalon and the cerebellum, of toads in response to configurational moving visual stimuli: (i) a 0.4 cm × 2.8 cm worm-like stripe (W) which elicited prey catching responses, (ii) a 8.4 cm × 8.4 cm square (S) that released predator avoidance responses, and (iii) a 2.8 cm × 0.4 cm antiworm-like stripe (A) which elicited no motor activity.For various brain nuclei different relationships were obtained: The optic tectum showed statistical significant higher 2DG uptake during worm-stimulation (¯X _W) than during antiworm stimulation (¯X _A), i.e.¯X _W>¯X _A. The latter visual pattern led to a 2DG utilization that was statistically significant stronger than during stimulation with a square (¯X _S), i.e.¯X _A>¯X _S. Thus, in comparison between right and left hemisphere as well as between brains the following ratios were obtained:Optic tectum:¯X _W>¯X _A>¯X _S; nucleus isthmi:¯X _W>¯X _A-¯X _s; posterodorsal lateral thalamic nucleus:¯X _S>¯X _A>¯X _W; posteroventral lateral thalamic nucleus:¯X _S>¯X _A¯X _W; posterior thalamic nucleus:¯X _W>¯X _A¯X _S; anteripr division of the lateral thalamic nucleus:¯X _W>¯X _A¯X _S; anterior thalamic nucleus:¯X _A>¯X _S>¯X _W; nucleus of Bellonci and dorsal division of the ventrolateral thalamic nucleus:¯X _W¯X _A¯X _S; cerebellum:¯X _S¯X _W>¯X _A.Abbreviations A anterior thalamic nucleus - Cb cerebellum - Hyp hypothalamus - Ist nucleus isthmi - cl. Ist contralateral Ist - La lateral thalamic nucleus, anterior division - Lpd lateral thalamic nucleus, posterodorsal division - Lpv lateral thalamic nucleus, posteroventral division - MP medial pallium - NB/VLd nucleus of Bellonci and ventrolateral thalamic nucleus, dorsal division - P posterior thalamic nucleus - PO preoptic area - Sna snapping evoking area=ventrolateral tectum - Str striatum - Tec tectum opticum     

Cellular morphogenesis in a halophilic archaebacterium

Cultures of a red halophilic archaebacterium exhibiting a complex morphology and cellular morphogenesis were obtained on a medium containingHalobacterium cutirubrum cell lysate. On primary culture the organism grew as an amorphous cellular mass 20 or more micrometers in diameter and underwent multiple internal cellular subdivision to produce a multicellular structure consisting of cuboidal cells of submicron dimensions. These disaggregated, elongated, cells became motile and multiplied by budding, thereby resembling the eubacteriumGeodermatophilus. The new isolates are identified as archaebacteria on the basis of their response to antibiotics, probable absence of peptidoglycan, and the presence of ether-linked lipids.     

The effect of glucose on cellobiose uptake and β-D-glucosidase activity inStreptomyces granaticolor

Glucose inhibits the inducible synthesis of β-D-glucosidase inStreptomyces granaticolor. Neither cAMP nor cGMP influence the inhibitory effect of glucose. Glucose also inhibits the inducible synthesis of the cellobiose uptake system but has no effect on its activity. This may be the mechanism underlying glucose inhibition of induction of β-D-glucosidase inS.granaticolor.     

A comparative study of the enzymatic hydrolysis of acid-pretreated white pine and mixed hardwood

Removal of hemicellulose by acid pretreatment in a flow reactor followed by enzymatic hydrolysis of the neutralized slurry has resulted in glucose yields as high as 95% for mixed hardwood. For white pine, however, the maximum glucose yield is 65%. Although pine has a higher extractives content, removal of the extractives prior to enzymatic hydrolysis does not increases the glucose yield. Pore size measurements reveal that the increase in pore volume, in the size range of the cellulase molecule, following pretreatment for pine is only about one-half the value obtained with mixed hardwood. This suggests that pore volume is an important determinant of substrate-enzyme reactivity.     

Model of calcium movements during activation in the sarcomere of frog skeletal muscle

A model of calcium movement during activation of frog skeletal muscle is described. The model was based on the half sarcomere of a myofibril and included compartments representing the terminal cisternae, the longitudinal sarcoplasmic reticulum, the extramyofibrillar space, and the myofibrillar space. The calcium-binding proteins troponin, parvalbumin, and calsequestrin were present in appropriate locations and with realistic binding kinetics. During activation a time-dependent permeability in the terminal cisternal wall led to calcium release into the myoplasm and its diffusion through the myoplasm longitudinally and radially was computed. After adjustment of three parameters, the model produced a myoplasmic free-calcium concentration that was very similar to those recorded experimentally with calcium indicators. The model has been used to demonstrate the importance of parvalbumin in the relaxation of skeletal muscle, to describe the time course and magnitude of calcium gradients associated with diffusion across the sarcomere, and to estimate the errors associated with the use of aequorin as an intracellular calcium indicator in muscle.     

Trace fossils in upper cretaceous argillaceous marine facies of the U.S. Western interior

Argillaceous strata of the Greenhorn and Niobrara depositional cycles contain an extensive, though spottily developed, record of tracemaking organisms. These beds are assignable to five facies, four of which represent the gradation from nearshore sandy shales to far offshore calcareous shales, the fifth representing anoxic or nearly anoxic bottom conditions. In strata studied by us the best potential for trace fossil preservation was in deposits characterized by pronounced textural variation, such as shales with sandstone interbeds, shales with thin lenses of siltstone or sandstone, or sandy and silty shales (= mudstones). In pure clayey shales and calcareous shales, trace fossils are preserved best in concretionary structures. Our study suggests that except for shales rich in organics, trace-making organisms were common and widespread in argillaceous muds of the Western Interior. Initial fluidity, high degree of compaction, and textural homogeneity are principal reasons for the poor record of trace makers in pure, clayey shales.     

Retrieval of lysosomal membrane and acid phosphatase from phagolysosomes of Paramecium caudatum

Little is known about the fate of lysosomal membrane in phagocytic cells. Because the age of the digestive vacuoles in Paramecium caudatum can be easily determined, we have been able to study the dynamic membrane events in the older vacuoles. Late in the phagolysosomal stage (DV-III) the vacuole membrane undergoes a burst of tubule formation. The tubules expand into vesicles which have characteristics resembling lysosomes in both thin sections and freeze-fracture replicas. The tubules also contain acid phosphatase activity when they arise from acid phosphatase-reactive vacuoles. We conclude that after active digestion lysosomal membrane is retrieved in whole or in part along with some membrane-associated hydrolases. A logical extension of these results is that the lysosome-like vesicles, after being recharged with hydrolases by fusing with primary lysosomes, are recycled back to DV-II for reuse.