Treatment of dairy industry wastewater with an anaerobic filter

Summary Concentrations of up to 10.2 g COD/L were applied to an horizontal anaerobic filter at 40°C, obtaining efficiencies in COD removal of 85%. The contents of the reactor are kept mixed by recycling and at a pH value of 6.9.The addition of alkali to the influent increases the production of biogas reaching a maximum of 250 L of methane per kg of COD removed.Career Investigator of the Consejo Nacional de Investigaciones Cientificas y Técnicas (R. Argentina).Fellow of the Consejo Nacional de Investigaciones Cientificas y Técnicas (R. Argentina).     

Effect of exogenous application of gibberellic acid on color change and phenylalanine ammonia-lyase, chlorophyllase, and peroxidase activities during ripening of strawberry fruit (Fragaria x ananassa Duch.)

The effect of exogenously applied gibberellic acid (GA₃) on the postharvest color change of strawberry fruit was evaluated through their external color and surface color parameters. A significant delay on color evolution was observed in fruits treated with GA₃. The evolution of activities of phenylalanine ammonia-lyase (PAL), chlorophyllase, and peroxidase was also analyzed. PAL activity increased during strawberry ripening, but in fruits treated with GA₃ the increase in such activity was slower, and, probably as consequence, the development of red color was delayed. Moreover, the activity of chlorophyllase and peroxidase, enzymes possibly involved in chlorophyll metabolism, decreased during strawberry ripening. However, a delay was observed in the decrease of such activities in GA₃-treated fruits.Abbreviations PAL phenylalanine ammonia-lyase - GA₃ gibberellic acid₃ - PVPP polyvinylpolyprrolidone - CEAU chlorophyllase enzymic activity unit - PEAU peroxidase enzymic activity unit - LSD least significant difference. Fellow of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) de la República Argentina. Author for correspondence.Members of the Research Career of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) de la República Argentina.     

Light and electron microscopy of granules in the toad choroid plexus

Summary Two types of granules can be distinguished in the toad choroid plexus under the light microscope: pigment granules, mainly localized in the cells that line the free ends of the choroidal villi, and Gomori-positive granules, present in most epithelial cells.The ultrastructural analysis of the choroid plexus reveals three types of granules: multivesicular bodies (MVB), multigranulous bodies (MGB) and dense bodies (DB), and intermediate stages between the last two bodies. The pigment granules seen under the light microscope probably correspond to the DB of the electron micrographs, and the Gomori-positive granules to the MGB. The probable role of these bodies is discussed and so is the significance of the glycogen present in the choroidal cells, their processes and endothelium.This study was partially supported by the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the Rockefeller Foundation (School grant RF — 58028).Fellow of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina. The author wishes to thank Prof. M. H. Burgos for his constant interest. His thanks are also due to Prof. H. Heller for providing certain facilities in his department and for his criticism.     

ZIO staining in synaptic vesicles of the rat pineal nerves after inhibition of serotonin and noradrenaline synthesizing enzymes

Summary Two compartments have been defined in monoaminergic synaptic vesicles: the core or central compartment, storage site for monoamines, and the matrix or outer compartment, of unknown function. The outer compartment reacts with the mixture of zinc iodide-osmium tetroxide (ZIO). This reaction is temperature and time dependent and may be abolished by -SH reagents.The effect of drugs inhibiting the synthesis of serotonin and noradrenaline (stored in the core) on the ZIO reaction in the matrix was studied in synaptic vesicles of rat pineal nerves. The inhibitors of monoamine synthesis abolish or decrease the ZIO reaction directly or in combination with the administration of tyramine. This effect is temperature dependent suggesting that the drugs act on different components of the matrix that react with ZIO at different temperatures. A comparison of the present results with those obtained with -SH reagents seems to indicate that the drugs assayed act, at least in part, by changing the accessibility of-SH groups in vesicle proteins. (An abstract of this paper was presented at the 7th International Congress of Pharmacology, Paris, 1978.)Supported by grants from the Consejo Nacional de Investigaciones Cientificas y Técnicas, CONICET, and the Secretaría de Ciencia y Técnica, SECYT, ArgentinaWe are grateful to Margarita López de Cáceres for technical assistance, to Adriana Contreras for the electron micrographs and to María Aued de Rau for the illustrations. Rita Cardoni is a fellow of the Consejo Nacional de Investigaciones Cientificas y Técnicas, Argentina     

Horizontal reactor for the continuous production of ethanol by yeasts immobilized in pectin

Summary Yeast cells (Saccharomyces cerevisiae) were immobilized in pectin gel, incubated 12 h at 30°C and then used for the continuous production of ethanol employing a wedge-shaped horizontal reactor and sugar cane molasses as the carbon source. Under steady state conditions the mean residence time was 1.6 h and the volumetric productivity 40 g EtOH/hl. The gas evolved was easily released. Successive batch incubation in a synthetic medium substantially restored the fermentative capacity of the beads already used in the continuous assay.Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del IPN, México D.F.Member of the Scientific Researcher's Career of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.     

Cytochemistry of 5-hydroxytryptamine at the electron microscope level

Summary The nerves of rat pineal gland are known to contain norepinephrine and 5-hydroxytryptamine. With the glutaraldehyde-dichromate reaction for the cytochemical localization of unsubstituted catechol- and indoleamines, dense reactive granules could be demonstrated in such endings. A similar reaction was observed in the adrenergic nerves supplying the vas deferens and storing exclusively norepinephrine. Formaldehyde fixation, prior to the glutaraldehyde-dichromate treatment, interferes with the reaction given by catecholamines not affecting the indolic reactive sites. After this combined procedure pineal nerves still exhibited the dense reactive granules, while these were not found in the nerves of the vas deferens. Following bilateral cervical sympathectomy reactive granules disappeared from the perivascular processes of the pineal gland. No reaction could be observed in the cytoplasm of parenchymal cells neither in their perivascular processes.These cytochemical results suggest that both catecholamines and 5-hydroxytryptamine are contained within the granulated vesicles of pineal nerves.This work has been supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina and U.S.Air Force (AF-AFOSR 963-66).Fellow of the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina. We want to express our gratitude to Prof. E. De Robertis for his constant help and encouragement; and to Miss Nélida Fernández Oranges, Mr. Raúl Castelli and Mr. Alberto Sáenz for their skillful technical assistance.     

Differences between median eminence and neural lobe in amphibians

Summary The neurohypophysis of the toad Bufo arenarum Hensel can be subdivided into two well defined zones: the median eminence and the neural lobe. In its turn, the median eminence consists of two zones: a neural subependymal one, containing the axons of the hypothalamic-neurohypophysial tract; and a glandular one, made up of the capillaries of the primary plexus of the portal hypophysial system and of neurosecretory axons.Different staining techniques and certain experimental procedures (inanition, dehydration and adenohypophysectomy) showed that there are differences between the neurosecretory material of the neural lobe, which is a place of hormone liberation into the systematic circulation, and the neurosecretory material of the median eminence, which is the site of release of adenohypophysis-stimulating substances into the portal vessels.This work was introduced at the III Sesiones Científicas de Biología, Rosario, Argentina, March, 1965. The study was partially supported by the Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina) and The Rockefeller Foundation (School grant RF-58028).Fellow of the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina. The author wishes to express his indebtedness to Dr. M. H. Burgos and Dr. F. Sacerdote for their help and criticism, to Miss B. Rodriguez. Miss M. Masot and Mr. L. Castro for their technical assistance.     

The effects of adenohypophysectomy on the hypothalamic-hypophysial neurosecretory system and the adrenal gland of the toad Bufo arenarum Hensel

Summary The effects of adenohypophysectomy were studied on the hypothalamichypophysial neurosecretory system and the adrenal glands of Bufo arenarum Hensel. An increase in vascularization of the pars intermedia was found and the neurosecretory material (NSM) in the glandular region of the median eminence disappeared. Its reappearance later was accompanied by hypertrophy of the pars intermedia; differentiated chromophil cells appeared in the pars intermedia around the vessels and, at the same time, the adrenal reverted to normal. These findings are interpreted as hypertrophy and differentiation of the pars intermedia with replacement, at least partly, of the functions of the pars distalis. The probable mechanism of differentiation and the functions of chromophil cells of the pars intermedia are discussed.This paper was presented at the VI Reunión de la Asociación Latinoamericana de Ciencias Fisiológicas (A.L.A.C.F.), Viña del Mar, Chile, 1964. It was carried out under the auspices of the Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina) and the Rockefeller Foundation (School grant RF-58028).Fellow of the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.The authors wish to thank Prof. M. H. Burgos for his constant interest, Prof. B. A. Houssay, Prof. H. Heller and Dr. J. H. Tramezzani for their criticisms, Miss B. Rodriguez and Mr. L. Castro for their technical assistance.     

Seasonal variation of carrageenans in tetrasporic,cystocarpic and ‘sterile’ stages of Gigartina skottsbergii S. et G. (Rhodophyta,Gigartinales)

Cystocarpic and sterile plants of Gigartina skottsbergii produce -carrageenans, while tetrasporophytes produce -carrageenans. No seasonal variation in the carrageenan yields in the three stages was evident. Yields were clearly higher in cystocarpic (34.1–64.7%) and sterile samples (32.3–71.8%) than in tetrasporic plants (10.1–34.0%). Chemical characteristics of the polysaccharides for any stage are the same throughout the year.The authors are Research Members of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.The authors are Research Members of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.     

The reticular substance of the medulla oblongata of the albino rat

Summary The region of the reticular giganto-cellular nucleus, perfused with formalin and postfixed in osmium tetroxide, was studied with histochemical and electron microscopic techniques. The perikarya of the neurons have two zones. The peripheral cytoplasm contains Nissl bodies, mitochondria, and free RNP particles. The juxtanuclear cytoplasm contains the Golgi complex, mitochondria, RNP particles and dense bodies. The nucleus is indented and has a prominent nucleolus and a paranucleolar body. Dense bodies are found along the axon and dendrites as well. Three different types of synapses are described and two types of synaptic vesicles (spherical and ellipsoidal) are shown.The capillary endothelium shows microvilli and marginal flaps. The endothelial cytoplasm contains vacuoles, micropinocytotic vesicles, and a few dense bodies. Processes of pericapillary cells, surrounded by a basement membrane, also contain dense bodies. The dense bodies found in the neurons and endothelial cells show acid phosphatase activity. On the basis of their morphology and their enzymatic activity these bodies are identified as lysosomes.Partially supported by a school grant No RF 62051 from the Rockefeller Foundation, New York, USA, and Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.Fellows of the Consejo National de Investigaciones Científicas y Técnicas, Argentina. The authors wish to thank Dr. Mario H. Burgos for his constant interest and criticism, and to Dr. Eduardo Rodriguez Echandia and Dr. Fabio L. Sacerdote for their valuable assistance.     

Neuronal and glial differentiation in reaggregation cultures

Summary Dissociation and reaggregation cultures from different portions of the chick embryo neural tube were made, and the resulting aggregates were fixed for electron microscopy after 1, 5, 8, 14, 16 and 22 days in vitro. All cultures (pure aggregates of telencephalon, optic lobe or neural retina, and combined aggregates made from mixtures of optic lobe plus neural retina or optic lobe plus telencephalon) show a common timing of neuronal and glial morphological differentiation.During the first week in vitro, some cells developed neuronal characteristics in the absence of morphological evidence of glial differentiation. Numerous axonic processes usually formed fascicles with all the fibers running parallel to each other. Axonic growth cones were abundant and a few immature synapses were also present. The second week in culture was characterized by the disappearance of growth cones and the increase in number and morphological maturation of synapses. Morphologically detectable glial differentiation began by the end of this week, and during the third week almost every neuronal element, including the axonic fascicles, became associated with glial cells showing astrocytic features.The authors are indebted to Mrs. N.A. de Pinto for her competent technical assistanceA.M.S. and R.A. are members of the Carrera del Investigador del Consejo Nacional de Investigaciones Cientifícas y Técnicas de la República ArgentinaThis work was supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina, and by NIH grant 5 ROI NS 06953-09 NEUA to Prof. Dr. E. De Robertis     

Diabetes-induced alteration in subcellular distribution of poly(A)-rich RNA from skeletal muscle

Summary Skeletal muscle ribosome preparations from diabetic rats have lower polysome content than those from normal animals. The ratio of poly(A) containing RNA between polysomes and postribosomal supernatant has been measured both in normal and diabetic rats. The results suggest that in diabetic animals there is a greater proportion of free poly(A) containing RNA, in postribosomal supernatant.This work was supported by Grants from the Consejo Nacional de Investigaciones Cientificas y Técnicas (República Argentina), Universidad Nacional de Buenos Aires, and partly under contract of the Ministére de la Politique Scientifique within the framework of the Association Euratom—University of Brussels—University of Pisa.     

Vascularization of the hypophysial region of the normal and adenohypophysectomized toad

Summary The study of standarized sections of the hypophysial regions, and in vivo observations showed the presence of communicating vessels between the capillary network of the median eminence and the large capillaries of the neurointermediate junction. Moreover, direct branches from the hypophysial artery are described which give off branches, at the level of the neural stalk, to the median eminence and to the large capillaries of the neurointermediate junction.A second portal system similar to the one described by Cruz has been observed. Its primary plexus originates in several encephalic regions, and its secondary plexus is distributed through the neural lobe and thence to the pars intermedia. The course of flow in this system is a descending one. The arterial contribution to this system appears to arise from branches from the basilar and retroinfundibular arteries. — There are small venous-type vessels between the large capillaries of the neurointermediate junction and the posterodorsal region of the pars distalis. — After adenohypophysectomy, the blood which normally goes towards the pars distalis, flows towards the pars intermedia, following the path of the communicating vessels between the median eminence and the pars intermedia.This paper was presented at the VII Reunion de la Asociación Latinoamericana de Ciencias Fisiológicas (A.L.A.C.F.), Mar del Plata, Argentina, 1966. It was carried out under the auspices of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the Rockefeller Foundation (School grant RF-58028).Fellows of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina. — The authors wish to thank Prof. B. A. Houssay and Drs. J. H. Tramezzani and J. la Pointe for their criticism, to Prof. M. H. Burgos and Dr. F. Sacerdote for their help.     

Enzyme polymorphism in a population of Calomys musculinus (Rodentia,Cricetidae)

NAD-linked lactate, malate, glycerophosphate, alcohol and nonspecific dehydrogenases, aspartate aminotransferases, and soluble esterases from extracts of tissues of individuals from a wild population of Calomys musculinus (Rodentia, Cricetidae) have been analyzed by means of starch gel electrophoresis and specific staining. Allelic frequencies and heterozygosity have been determined. Mendelian inheritance of some of the variants detected was confirmed by breeding experiments. Ten out of fifteen (66.6%) of the genetic loci investigated presented polymorphism. Mean heterozygosity per locus was very high (H=0.2014, se 0.046).This work has been supported, in part, by grants from the Secretaria de Ciencia y Tecnología de la Nación (National Program for Endemic Diseases) and from the Fundación Emilio Ocampo. C. N. G. is a Fellow and A. B. a Career Investigator of the Consejo Nacional de Investigaciones Científicas y Técnicas of Argentina.     

Cyclic AMP-dependent protein kinase from Ustilago maydis

Summary Ustilago maydis was surveyed for cyclic AMP-dependent protein kinase activity. Using a combination of ion-exchange and molecular filtration techniques, we demonstrate that there is only one form of cyclic AMP-dependent protein kinase in the cytosolic fraction of the fungus. The kinase activity is specifically activated by cyclic AMP and utilizes protamine and kemptide as substrates. Most, if not all, of the cyclic AMP binding detected in the soluble fraction is associated with the protein kinase activity. Cyclic AMP-dependent protein kinase is completely dissociated by cyclic AMP into catalytic and regulatory subunits having an apparent molecular weight of 35 000 daltons as judged by sucrose gradient centrifugation.Post graduate fellow from the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, Argentina).Career investigator from CONICET.     

Ultrastructural changes of the neurohypophysis of the rat after castration

Summary The infundibular processes of the neurohypophysis of male and female rats were studied after different periods of castration. After seven days an increase in neurosecretory granules was observed. Two types of neurosecretory nerve endings were identified: dark ones, with dense neurosecretory elementary granules of 1600 A, and clear ones, with lighter neurosecretory granules of 1800 A. Protoplasmatic pituicytes showed a large increase in lipid granules together with a general hypertrophy. After one week of castration but with hormonal therapy the protoplasmatic pituicytes appeared normal or even showed less lipid granules than in the controls.With one month of castration the changes already mentioned in the nerve endings and pituicytes were more pronounced and after six months even more accentuated. Two types of neurosecretory nerve endings were clearly identified and the protoplasmatic pituicytes were loaded with lipid granules.The probable significance of the two different neurosecretory axons was discussed in relation to recent studies on the isolation of neurosecretory terminals from the neurohypophysis. The changes in the protoplasmatic pituicytes were considered in relation to the possible significance of the lipid granules.Supported by grants from the Consejo Nacional de Investigaciones Cientificas y Técnicas and by the Air Force Office of Scientific Research (AF-AFOSR 963-67).We are deeply indebted to Mrs. Defilippi-Novoa and Mr. Alberto Saenz for their skillful assistence.Associated Investigator, Consejo Nacional de Investigaliones Científicas y Técnicas, Argentina.     

Presynaptic tubular structures in photoreceptor cells

Summary After the application of fixatives including phosphotungstic acid or a mixture of osmium tetroxide and zinc iodide, complex tubular structures are evident in the presynaptic side of the synapses between photoreceptor and bipolar cells of the rat's retina. In the first case only the limiting membranes are visualized, while in the second only the content of the tubules is stained. These tubules seem to be related, on a morphological ground, with the formation of synaptic vesicles. These tubular structures are not observed when fixation is done with osmium tetroxide or glutaraldehyde-osmium tetroxide.This work has been supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina, and from National Institutes of Health, U.S.A., (5 RO1 NS 06953-05 NEUA).We want to express our gratitude to Mrs. Haydée Agoff de Zimman and Mr. Alberto Saénz for their skillful technical assistance.     

On the regeneration of the eye in Helix aspersa and Cryptomphallus aspersa

Summary The distal half of the posterior tentacle of adult Helix aspersa and Cryptomphallus aspersa was removed and the proximal half was studied with light and electron microscopy after different intervals. The tentacle itself does not regenerate, but the receptor organs at the distal end of the normal tentacle differentiate at the level of the section. The newly formed eye is smaller than the control; however, its components and subcellular characteristics resemble those of the normal eye.Work supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina, and from National Institutes of Health (2 RO1 NS 06953-07 NEUA) USA.We are greatly indebted to Miss Margarita López for her skilful technical assistance and to Mr. Alberto Saénz for the electron micrographs.     

DNA of Akodon (Rodentia,Cricetidae). I. Biophysical characterization

Buoyant density in CsCl, melting temperature, and G + C base content of the DNA from four species of Akodon (Rodentia, Cricetidae) were determined. The buoyant density values of 1.699–1.701 g/cm³ were in accordance with the data reported for other cricetids. No satellite bands were seen in neutral CsCl. The T _m values determined in 1 × SSC ranged from 86.2 to 87.0 C, which corresponds to G + C contents of 41.2–43.2%. There was good agreement in DNA base composition of the four species, although values were slightly higher in A. obscurus, suggesting a certain degree of interspecies variability.This study was supported by grants from Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, and Organización de Estados Americanos.     

Twenty-four-hour rhythm in the mitotic activity and in the water and dry matter content of regenerating liver

Summary A twenty-four hour rhythm is described in the variations of mitotic activity, dry weight, and water content of the regenerating liver of mice hepatectomized about noon. These variables have their maximal value at the onset of the rest periods in the morning and their minimal values at the initiation of the body activity periods in the evening. The rhythm is well defined on the second day and is repeated on the third day on a higher level.We acknowledge the assistance of Mrs. R. Cavoura in performing the hepatectomies and that of Mrs. M. A. V. Albornoz in making the histologic slides.The present work was carried out with the help of grants from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and Liga Mendocina de Lucha contra el Cáncer.