Tumor necrosis factor-α in macrophages of heart,liver, kidney,and in the pituitary gland

The relationship between myonuclear number, cellular size, succinate dehydrogenase activity, and myosin type was examined in single fiber segments (n=54; 9±3 mm long) mechanically dissected from soleus and plantaris muscles of adult rats. One end of each fiber segment was stained for DNA before quantitative photometric analysis of succinate dehydrogenase activity; the other end was double immunolabelled with fast and slow myosin heavy chain monoclonal antibodies. Mean±S.D. cytoplasmic volume/myonucleus ratio was higher in fast and slow plantaris fibers (112±69 vs. 34±21x10³ m³) than fast and slow soleus fibers (40±20 vs. 30±14x10³ m³), respectively. Slow fibers always had small volumes/myonucleus, regardless of fiber diameter, succinate dehydrogenase activity, or muscle of origin. In contrast, smaller diameter (<70 m) fast soleus and plantaris fibers with high succinate dehydrogenase activity appeared to have low volumes/myonucleus while larger diameter (>70 m) fast fibers with low succinate dehydrogenase activity always had large volume/myonucleus. Slow soleus fibers had significantly greater numbers of myonuclei/mm than did either fast soleus or fast plantaris fibers (116±51 vs. 55±22 and 44±23), respectively. These data suggest that the myonuclear domain is more limited in slow than fast fibers and in the fibers with a high, compared to a low, oxidative metabolic capability.     

Quantitative analysis of muscle breakdown during starvation in the marine flatfish Pleuronectes platessa

Summary The present study describes the effects of starvation for a duration of four months on the ultrastructure of skeletal muscles from the marine flatfish (Pleuronectes platessa L.). Starvation is associated with a decrease in resting metabolic rate from 20.1±2.2 to 11.6±1.5mg-O₂/kg/h (P<0.05) and muscle wasting. Median fibre size fell from 700 m² to 500 m² in intermediate (fast oxidative) and from 1,800 m² to 600 m² in starved, white (fast-glycolytic) muscle fibres. In contrast, median fibre size in red (slow oxidative) muscle remained within the range 300–400 m². The fraction of red fibre volume occupied by myofibrils (58.6%) and mitochondria (24.5%) did not change significantly with starvation. There was, however, a decrease in stored lipid (10.7% to 3.2%) and an alteration in the structure of the cristae in mitochondria from red muscle.Atrophy of white muscle fibres is associated with a decrease in both the diameter and fractional volume occupied by myofibrils (85.7% to 61.9% P < 0.01). In a high proportion of white fibres peripheral degeneration of Z-discs is evident causing an unravelling of the thin filament lattice. It is suggested that this allows a partial decrease in myofibril diameter and hence the maintenance of contractile function in muscle from starved fish. In severely degenerating white fibres, disorganised thick and thin filaments and numerous multimembrane lysosome-like vesicles are observed.Starvation results in an increase in the average content of mitochondria in white fibres from 2.2 to 6.7% (P<0.01). In fed plaice mitochondria constitute less than 1% of the volume of the white fibre in 43.5% of the fibres. The proportion of white fibres containing more than 6% mitochondria increases from 6.5% to 58% with starvation.     

Calcium in isolated mitochondria from the left ventricular wall

Summary The content of calcium per mg mitochondrial protein has been measured by conventional biochemical methods in myocardial tissue of some mammalian species. In addition, a method is presented for (1) the analysis of mitochondrial volumes in the same tissues and (2) calculating the amount of calcium in units of 10⁶ mitochondria.It appears that a highly significant correlation exists between the calcium content and the number of mitochondria, with a positive correlation coefficient of 0.92. The mean mitochondrial volume in fractions of the rabbit myocardium was found to be 1.3386 m³. Electron microscopic studies demonstrate pure mitochondrial fractions and only moderate structural alterations. The method described may represent a useful supplement for the estimation of calcium fluxes in mitochondria and of alterations in their volume, number and structure under conditions of myocardial ischemia.This work was supported by grants from the Norwegian Council on Cardiovascular Disease and from The Norwegian Research Council for Science and the Humanities     

Oxygen consumption and the composition of skeletal muscle tissue after training and inactivation in the European woodmouse (Apodemus sylvaticus)

Summary In European woodmice the amount and intensity of daily activity was compared to oxygen uptake and to the potential for oxidative metabolism of heart and skeletal muscle. One group of animals was inactivated by exposition to light during night time; another group of animals was trained by enforced running on a treadmill. The oxidative potential of the muscle tissue was assessed by morphometry of capillaries and mitochondria. A novel sampling technique was used which allowed us to obtain morphological data related to single muscles, to muscle groups, and finally to whole body muscle mass.Reducing the spontaneous activity by ten fold had no effect on oxygen uptake nor on capillaries or mitochondria in locomotory muscles. Mitochondrial volume was reduced, however, in heart and diaphragm. Enforced running increased the weight specific maximal oxygen uptake significantly. It also increased the mitochondrial volume in heart and diaphragm as well as in M. tibialis anterior. Capillary densities were neither affected by training nor by inactivation. A significant correlation was found between the capillary density and the volume density of mitochondria in all muscles analysed morphometrically. For the whole skeletal muscle mass of a European woodmouse the inner mitochondrial membranes were estimated to cover 30 m². The oxygen consumption per unit time and per unit volume of muscle mitochondrion was found to be identical in all groups of animals (4.9 ml O₂ min^–1 cm^–3).Symbols S _v (im,m) surface area of inner mitochondrial membranes per unit mitochondrial volume - V _v (mt, f) volume density of mitochondria (mitochondrial volume per fiber volume) - V (mt) total mitochondrial volume - V (f) muscle volume - N _A (c, f) capillary density - (f) mean fiber cross-sectional area     

Capillarization,mitochondrial densities,oxygen diffusion distances and innervation of red and white muscle of the lizard Dipsosaurus dorsalis

Summary The white and red regions of the iliofibularis muscle of the lizard Dipsosaurus dorsalis were analyzed using histologic and morphometric analysis. These regions are composed of fast glycolytic (FG) and both fast oxidative, glycolytic (FOG) and tonic fibers, respectively. Endplate morphology and number of endplates per fiber were estimated from fibers from both areas. Capillary volume densities of the red and white regions were quantified from transverse sections. Mitochondrial volume of fibers from the red and white regions were estimated from electron micrographs.All fibers from the white region of the iliofibularis possessed a single, well defined endplate, as did most red region fibers. The remaining red fibers (28±5%) possessed an average of 14.7±3 endplates each, distributed along the entire length of the fiber at intervals of approximately 1124 m.Red fibers possessed twice the mitochondrial volume of white fibers (7.6±0.4%, red; 3.8±0.3%, white). Mitochondria were distributed uniformly through the fibers from both regions. Capillary anisotropy was low ( = 1.018) in both regions. Capillary densities of the red region (629±35 mm^-2) were much greater than those of the corresponding White region (73±8 mm^-2).The data indicate that capillary densities, mitochondrial volumes and theoretical diffusion distances correlate well with the oxidative capacity of lizard muscle fibers. Tonic fibrs of this species appear oxidative and therefore metabolically capable of functioning during locomotion. The similar mitochondrial volumes and capillary densities of reptilian and mammalian muscles suggest that the greater oxidative capacity of mammalian muscle is due in part to possession of more oxidatively active mitochondria rather than to possession of more mitochondria per se.     

Quantitation of pulmonary neuroepithelial bodies in pre- and postnatal rabbits

Summary The size, density and total number of neuroepithelial bodies (NEB) in the lungs of late fetal, neonatal, and mature rabbits were determined using fluorescence microscopy. In this study lungs from 27-, 29-, 30-, and 31-day fetuses; neonates of ages 2, 7, and 30 days; and 4- and 7(+)-month-old rabbits, were used. The total number of NEB in the entire lung of rabbits from each age group was estimated based on measurements of collapsed lung volume, average NEB diameter, and NEB density (number/mm²). Average NEB diameter increased between 27 and 29 days gestation, then remained constant at 42–44 m between 29 days gestation and two days post-partum. Thereafter the diameter was significantly reduced in the 7-day group (33.7 m) and further reduced in the 4-month group (20.3 m). NEB density was initially high in 27-day fetuses (3.87/mm²), decreased significantly by 30 days gestation, increased to a high level by 2 days post-partum, then fell steadily, reaching the lowest level in the adult (0.15/mm²). This steady decrease in density was paralleled by a large increase in lung volume. The estimated total number of NEB in the lung was constant in all age groups except for a significant drop at 30 and 31 days gestation. These data indicate that the total number of NEB is maintained into adulthood; however, the density and average diameter of NEB decreases rapidly after 2 days postpartum. A sharp decrease in both total number and density observed under fluorescence microscopy at 30 and 31 days gestation suggests a change in NEB cellular activity just prior to birth.     

Slow type muscle cells in the earthworm gizzard with a distinct,Ca2+-regulated myosin isoform

Summary Histochemical staining of the gizzard from the earthworm,Lumbricus terrestris, reveals low ATPase and high succinic dehydrogenase activity for all muscle cells as compared to the main part of the body wall. In accordance with the presence of slow type muscle cells in the gizzard, isolated actomyosin shows an ATPase activity three times lower than the body wall actomyosin.Gizzard myosin represents an isoform, distinct from those of the body wall muscle, by comparison of the light chain pattern in isoelectric focusing. No difference was observed in the Ca²⁺-regulatory properties between gizzard and body wall actomyosin. Gizzard actomyosin is dual-regulated, and the myosin contains a regulatory light chain which is reversibly dissociated by EDTA. Isolated gizzard binds two molecules of Ca²⁺ per molecule, in the same range of free Ca²⁺ concentrations over which actomyosin is activated, suggesting that the myosin-linked regulatory system is mediated by direct binding of Ca²⁺.The molar ratios of the major contractile proteins of body wall and gizzard actomyosins differ considerably, indicating a structural diversity of fast and slow type muscle cells.Abbreviations DTNB 5,5-dithio-bis-(2-nitrobenzoic acid) - DTT dithiothreitol - EDTA ethylenediaminetetraacetic acid - EGTA ethyleneglycol-bis(-aminoethyl ether)-N,N,N,N-tetraacetic acid - HC myosin heavy chain(s) - HMM heavy meromyosin (product of limited proteolytic cleavage of myosin) - IEF isoelectric focusing - LC myosin light chain(s) - PAGE polyacrylamide gel electrophoresis - PMSF phenylmethylsulfonyl fluoride - SDH succinic dehydrogenase - SDS sodium dodecyl sulfate - Tris tris(hydroxymethyl)aminomethane     

Release of serotonin from nerve endings byl-5-hydroxytryptophan,α-methyl-m-tyramine,and elevated potassium ions

The release of [³H]5-hydroxytryptamine ([³H]5-HT) byl-5-hydroxytryptophan (L-5-HTP),-methyl-m-tyramine (-MMTA), and elevated levels of K⁺ was studied using crude synaptosomal preparations (P₂) isolated from the telencephalon of the rat and pigeon. Studies were conducted in vitro in the presence of either 2×10^–5 M tranylcypromine, which inhibited the MAO activity of both the extrasynaptosomal mitochondria and the mitochondria contained within the nerve endings (intrasynaptosomal mitochondria), or 2×10^–5 M nialamide, which inhibited the MAO activity of the extrasynaptosomal mitochondria under the experimental conditions used. In the P₂ fraction isolated from the rat, either 55 mM K⁺, 0.10 mMl-5-HTP, or 0.03 mM-MMTA significantly increased the release of [³H]5-HT above control levels, regardless of which MAO inhibitor was present in the medium. In the presence of tranylcypromine, this increased release by 55 mM K⁺ or 0.10 mMl-5-HTP was partially suppressed if Ca²⁺ was omitted from the medium. In the presence of nialamide, the release by 55 mM K⁺ was completely prevented if Ca²⁺ was omitted; the release byl-5-HTP was only partially affected. The release of [³H]5-HT by-MMTA did not appear to be markedly affected by removal of Ca²⁺, regardless of which MAO inhibitor was present. Very similar data were obtained in the presence of nialamide using the P₂ fraction isolated from the telencephalon of the pigeon, with the exception that 0.10 mMl-5-HTP caused an increase in the release of [³H]5-HIAA (which was not calcium-dependent) instead of [³H]5-HT. The data are discussed in     

Quantitative cytology of the egg and central cell of Plumbago zeylanica and its impact on cytoplasmic inheritance patterns

Summary The egg and central cells of Plumbago zeylanica have an average volume of 543,000 m³ and 2,560,000 m³ respectively, with surface areas of 38,600 m² and 154,000 m². The egg contains an average of 39,900 mitochondria and 730 plastids. The majority of the plastids are perinuclear (> 60%) with less than 40% in lateral areas or near the filiform apparatus. After fertilization, the number of maternal organelles exceeds paternal organelles by a ratio of 11,000 for mitochondria and 154 for plastids. The central cell contains an average of 178,700 mitochondria and 1,840 plastids. After fertilization, these organelles far exceed the number of sperm organelles transmitted, by a ratio of approx. 14,000 for plastids and 1820 for mitochondria. Biparental inheritance of plastids in the embryo is possible, but not favored; the only comparable data in Oenothera and Impatiens reveals that biparental inheritance is possible in up to 124 ratios. Plants lacking biparental plastid inheritance do not contain plastids in the sperm, and thus the presence of even few sperm plastids may result in expression. The number of paternal mitochondria transmitted into the central cell is greater than that transmitted into the egg as the result of preferential fertilization with the mitochondrion-rich dimorphic sperm cell, although the ratio of paternal to maternal mitochondria is 11,000 in the egg and 1820 in the central cell. The similarity in these ratios suggests that there is a critical dosage of mitochondria that is permissible within the zygotic and endospermatic lineages. This may represent either: (1) a maximum permissible value to prevent expression of paternal mitochondrial genome, (2) a minimum ratio required in order to permit recombination of maternal and paternal mitochondrial genomes, or (3) a cytoplasmic genome balance number.Abbreviations mtDNA mitochondrial DNA - S_ua sperm cell unassociated with the vegetative nucleus - S_vn sperm cell physically associated with the vegetative nucleus     

DIFFERENTIATION OF THE DIGESTIVE TRACT EPITHELIUM UNDER THE INFLUENCE OF THE HETEROLOGOUS MESENCHYME OF THE DIGESTIVE TRACT IN THE BIRD EMBRYOS

The endoderm of the oesophagus, proventriculus, gizzard or small intestine of the 5-day-old chick or quail embryo was cultivated in combination with homologous or heterologous mesenchyme on a WxxxOLFFyyy and HxxxAFFHNyyy medium for 7 to 21 days or on the chorio-allantoic membrane (CAM) for 8 days. With homologous mesenchyme the epithelium always differentiated homotypically. In association with heterologous mesenchyme, the differentiation of the epithelium was both homotypical and heterotypical depending on the region of the digestive tract. The oesophagus and small intestine differentiate mainly homotypically both in culture and on CAM, but the gizzard and proventriculus show heterotypic differentiation particularly on CAM. Thus, the endoderm of the digestive tract of the 5-day-old chick or quail embryo, though rather "determined", still reacts to the heterologous stimuli of the mesenchyme to some degree.     

Ultrastructural analysis ofSpinacia oleracea sperm cells isolated from mature pollen grains

Summary In isolated condition, the sperm cells ofSpinacia oleracea are no longer arranged in pairs as in the pollen grain. The vegetative membrane, which surrounds a sperm cell pair in a mature pollen grain, is lost during the isolation procedure. The sperm cells become spherical in shape.The isolated sperm cell is surrounded by an intact plasma membrane. The heterochromatic or euchromatic sperm cell nucleus is located in the cell center. Mitochondria are round to oval and have distinct cristae. Often they are clustered in groups of 5 to 10 mitochondria. Dictyosomes are present in the cytoplasm and consist of 4 to 5 cisterns. Endoplasmatic reticulum is mostly situated at the sperm cell periphery, as single cisterns very near the plasma membrane.From diameters of sectioned sperm cells in electron micrographs, it is possible to calculate the average diameter of the whole sperm cell. This average diameter is 3.66 m with a variation of 3.0 m to 4.2 m, resulting in an average volume of 25.6 m³. The nuclear volume is 12.8 m³ (50.0% of the whole cell) and the mitochondrial volume is 0.7 m³ (2.5% of the whole cell). The frequency distribution of the isolated sperm cells diameters shows only one peak with a normal distribution, indicating that there is no dimorphism in volume.     

Mitochondria in fine afferent nerve fibres of the knee joint in the cat: a quantitative electron-microscopical examination

The distribution of mitochondria, their content and concentration (expressed as the ratio of the mean volume of mitochondria and the surface of the sensory axon) were determined in group-III and-IV nerve fibres innervating the knee joint capsule in the cat. Mitochondria mainly accumulated in axonal swellings (beads) and end bulbs of the terminal branches. Between single nerve fibres, marked differences in the content and the concentration of mitochondria were obtained in proximal portions (inside of the perineurium) and in distal portions (unmyelinated sensory endings). In group-III nerve fibres, the mitochondrial concentration ranged from 0.005 to 0.030 m³/m² (proximal portion) and from 0.016 to 0.080 m³/m² (distal portion). In unmyelinated group-IV nerve fibres, the values also showed a broad variation ranging from 0.001 to 0.011 m³/m² (proximal portion) and from 0.003 to 0.019 m³/m² (distal portion). The wide range of mitochondrial concentrations may reflect different energy consumption during receptive processes: nerve fibres with a low mechanical threshold and a high probability of excitatory events may be rich in mitochondria, whereas fibres with a high mechanical threshold and a low probability of excitatory events may be poor in mitochondria.     

Genotypic effects on pollen morphology in sesame (Sesamum indicum L.)

Summary The morphology (shape, exine wall pattern, diameter, volume, surface area) of mature pollen grains from eight genotypes, four within each of two capsule types (dehiscent, indehiscent) was studied. The shape was a flattened sphere (oblate) with a P (polar axis diameter): E (equatorial axis diameter) ratio = 0.69. The exine wall pattern consisted of a series of furrows passing through the poles and intersecting the equatorial plane at right (90°) angles. In cross section, the furrows appeared to be associated with shallow U-shaped structures with the intine protruding between these structures. Over the eight genotypes, the diameter, volume, and surface area were 65 m, 147300 m³, and 13444 m², respectively. For all three related characters, highly significant differences between capsule type and genotypes within capsule type were obtained. For each character, the dehiscent capsule type mean was larger than the indehiscent capsule type mean with minimum overlap among the four genotype means within each capsule type. Possibly, the numerous and diverse pleiotropic effects associated with this simply-inherited recessive indehiscent capsule type character includes pollen dimensions.     

Detection of QTL controlling digestive efficiency and anatomy of the digestive tract in chicken fed a wheat-based diet

Background

Improving digestive efficiency is a major goal in poultry production, to reduce production costs, make possible the use of alternative feedstuffs and decrease the volume of manure produced. Since measuring digestive efficiency is difficult, identifying molecular markers associated with genes controlling this trait would be a valuable tool for selection. Detection of QTL (quantitative trait loci) was undertaken on 820 meat-type chickens in a F2 cross between D- and D+ lines divergently selected on low or high AMEn (apparent metabolizable energy value of diet corrected to 0 nitrogen balance) measured at three weeks in animals fed a low-quality diet. Birds were measured for 13 traits characterizing digestive efficiency (AMEn, coefficients of digestive utilization of starch, lipids, proteins and dry matter (CDUS, CDUL, CDUP, CDUDM)), anatomy of the digestive tract (relative weights of the proventriculus, gizzard and intestine and proventriculus plus gizzard (RPW, RGW, RIW, RPGW), relative length and density of the intestine (RIL, ID), ratio of proventriculus and gizzard to intestine weight (PG/I); and body weight at 23 days of age. Animals were genotyped for 6000 SNPs (single nucleotide polymorphisms) distributed on 28 autosomes, the Z chromosome and one unassigned linkage group.

Results

Nine QTL for digestive efficiency traits, 11 QTL for anatomy-related traits and two QTL for body weight at 23 days of age were detected. On chromosome 20, two significant QTL at the genome level co-localized for CDUS and CDUDM, i.e. two traits that are highly correlated genetically. Moreover, on chromosome 16, chromosome-wide QTL for AMEn, CDUS, CDUDM and CDUP, on chromosomes 23 and 26, chromosome-wide QTL for CDUS, on chromosomes 16 and 26, co-localized QTL for digestive efficiency and the ratio of intestine length to body weight and on chromosome 27 a chromosome-wide QTL for CDUDM were identified.

Conclusions

This study identified several regions of the chicken genome involved in the control of digestive efficiency. Further studies are necessary to identify the underlying genes and to validate these in commercial populations and breeding environments.     

Morphology of horseradish peroxidase (HRP)-injected glial cells in the myenteric plexus of the guinea-pig

Glial cells of the myenteric plexus from guinea pig small intestine were intracellulary filled with horseradish peroxidase (HRP), and histochemically stained. Camera lucida-like drawings of twenty cells were morphologically and morphometrically analyzed. The cells have very small ellipsoid, somata (85±0.7 m equivalent diameter, i.e., about 330 m³ volume), and send up to 20 thin and short processes (less than 26 to about 110 m in length). The morphology of the cells appears to depend on their location within the plexus. Glial cells located within the ganglia are similar to CNS protoplasmic astrocytes; they are star-shaped, and their very short processes are irregularly, branched. In contrast, glial cells within the interganglionic fiber tracts resemble CNS fibrous astrocytes. They extend longer processes that are parallel to the fiber tracts, and show less tendency to branch. We propose that the morphology of enteric glia is determined by the structure of the microenvironment. Both cell types form several flat endfeet at a basal lamina either surrounding blood vessels or at the ganglionic border. Furthermore, the occurrence of holes in the glial cell processes suggests that particular neuronal cell processes may be enwrapped in a specific manner. Fractal analysis of camera lucida-like drawings of the cells showed that the cells have a highly complex surface structure, comparable to that of protoplasmic astrocytes in the brain. These tiny cells may possess a membrane surface area of 2000 m², almost 90% of which are contributed by the cell processes. This geometry may enable an intense exchange of metabolites and ions between neurons, glial cells, and the capillaries and/or environment of enteric ganglia.     

Quantitative immunocytochemical studies on differential induction of serine

Summary Differential induction of serine: pyruvate aminotransferase (SPT) in rat liver parenchymal cells by administration of glucagon or di-(2-ethylhexyl)phthalate (DEHP) was studied using post-embedding immunocytochemical techniques and morphometric methods. Two groups of rats were fasted for 5 days and daily received peritoneal injection of glucagon (300 g/100 g) or physiological saline. Another two groups of rats were fed on laboratory chow with or without 2% DEHP for 2 weeks. Livers were perfusionfixed, cut into tissue sections (50–100 ), and processed to cytochemistry for catalase, immunocytochemistry for SPT, and conventional procedures for electron microscopy. The morphometric analysis showed that glucagon injection has negligible effect on the volume and numerical density and mean diameter of peroxisomes, whereas volume density of mitochondria was decreased by 25%. By DEHP administration peroxisomes were about 3-fold increased in the volume and numerical density. Mitochondria was increased about 40% in the numerical density, but unchanged in the volume density. Light and electron microscopic immunocytochemistry demonstrated that glucagon injection exclusively enhanced mitochondrial SPT, whereas DEHP administration exclusively induced in peroxisomal SPT. Quantitative analysis showed that by the glucagon injection, the labeling density of mitochondria was increased about 4-fold, but that of peroxisomes was 1.6 times as much as control, while by DEHP administration, the labeling density of peroxisomes was enhanced about 3-fold but that of mitochondria was decreased by 13%. The results clearly indicate that glucagon induces mitochondrial SPT, whereas peroxisome proliferator, DEHP induces peroxisomal SPT.     

Muscle fibre types and metabolism in post-larval and adult stages of notothenioid fish

Summary A histochemical study was carried out on muscle fibre types in the myotomes of post-larval and adult stages of seven species of notothenioid fish. There was little interspecific variation in the distribution of muscle fibre types in post-larvae. Slow fibres (diameter range 15–60 m) which stained darkly for succinic dehydrogenase activity (SDHase) formed a superficial layer 1–2 fibres thick around the entire lateral surface of the trunk. In all species a narrow band of very small diameter fibres (diameter range 5–62 m), with only weak staining activity, occurred between the skin and slow fibre layer. These have the characteristics of tonic fibres found in other teleosts. The remainder of the myotome was composed of fast muscle fibres (diameter range 9–75 m), which stain weakly for SDHase, -glycerophosphate dehydrogenase, glycogen and lipid. Slow muscle fibres were only a minor component of the trunk muscles of adult stages of the pelagic species Champsocephalus gunnari and Pseudochaenichthys georgianus, consistent with a reliance on pectoral fin swimming during sustained activity. Of the other species examined only Psilodraco breviceps and Notothenia gibberifrons had more than a few percent of slow muscle in the trunk (20%–30% in posterior myotomes), suggesting a greater involvement of sub-carangiform swimming at cruising speeds. The ultrastructure of slow fibres from the pectoral fin adductor and myotomal muscles of a haemoglobinless (P. georgianus) and red-blooded species (P. breviceps), both active swimmers, were compared. Fibres contained loosely packed, and regularly shaped myofibrils numerous mitochondria, glycogen granules and occasional lipid droplets. Mitochondria occupied >50% of fibre volume in the haemoglobinless species P. georgianus, each myofibril was surrounded by one or more mitochondria with densely packed cristae. No significant differences, however, were found in mean diameter between fibres from red-blooded and haemoglobinless species. The activities of key enzymes of energy metabolism were determined in the slow (pectoral) and fast (myotomal) muscles of N. gibberifrons. In contrast to other demersal Antarctic fish examined, much higher glycolytic activities were found in fast muscle fibres, probably reflecting greater endurance during burst swimming.     

Power input measurements in a production scale bioreactor

Summary Power input measurements are carried out in a production bioreactor with a liquid volume up to 25 m³. The results show that the cavity formation principle is applicable to reactors at this scale. It can also be observed that empirical correlations are not useful to predict gassed power input accurately. It is found that at gas flow rates for normal production conditions (N_Q =0.1), the gassed power input is about 30–40 % of the non gassed power input.Nomenclature C_p specific heat J/kgK - D impeller diameter m - D_b1 impeller blade diameter m - d baffle diameter m - Fr Froude number - - g gravitation m/s² - h impeller clearance m - H liquid height m - N stirrer speed s^-1 - N_p power number - - N_Q gas flow (aeration) number - - N_Q ^* critical gasflow number for 3 cavity formation - - P_o ungassed power consumption W - P_g gassed power consumption W - Q gas flow rate (273 K, 10⁵ N/m²) m³/s - Re Reynolds number - - T tankdiameter m temperature K - t time s - V liquid volume m³ - ^Vtip impeller tip speed m/s - V_s impeller correlated superficial gas flow rate m/s - W impeller blade width m - density kg/m³     

Erythrocytes of Japanese Quail for Hemagglutination by Rubella Virus

Erythrocytes (RBC) of adult Japanese quail, Coturnix coturnix japonica, were found to be as sensitive as day-old chick RBC for rubella virus hemagglutination (HA). Various factors involved in the HA were studied with quail RBC as well as with adult pigeon and day-old chick RBC. Pigeon RBC, unlike chick and quail RBC, tended to show, without hemagglutinin, a pattern of sedimented RBC resembling the HA pattern by the virus at 4 C, to a lesser extent at room temperature, in 0.85% NaCl solution buffered with m/100 phosphate (PBS), and were prevented from doing so by addition of a small amount of bovine plasma albumin to the diluent. A small amount (about 10^?3 m ) of CaCL₂ in PBS gave higher HA titers. The HA titer was higher at 4 C than at room temperature and much reduced at 36 C with chick and quail RBC. With pigeon RBC, addition of bovine plasma albumin to the diluent tended to reduce HA titers. The HA titer was highest at pH 5.8 to 6.8, and was inversely proportional to the RBC concentration. Under the conditions established on the basis of these findings, chick and quail RBC gave similar HA titers, but pigeon RBC gave consistently higher titers. However, these types of RBC gave no significant difference in HA-inhibiting antibody titer when 4 units of hemagglutinin as determined with the homologous RBC was used.