Effects of feeding and starvation on growth and swimming activity in an obligatory air-breathing fish

Reared in (tubular) aquaria containing different depths of water, Ophiocephalus striatus (0.7 g, 4.5 cm body length), an obligatory air-breathing tropical fish, swam long or short distances to enable themselves to exchange atmospheric air. In each tested depth (2.5, 5.0, 15.5, 31.0 and 40.0 cm) series, one group was starved, while the other was fed ad libitum twice a day on fish muscle. In the shallowest water (2.5 cm depth), the feeding group surfaced 1,294 times, travelling 64.7 m at an energy cost of 20.4 mg dry fish substance/g live fish/day, against those exposed to the deepest water (40 cm depth), which expended 35.8 mg/g/day, swimming 1,503.4 m on 1,879 visits to the surface. The starving group surfaced only 482 times, travelling 24.1 m at an expense of 5.8 mg/g/day in the shallowest water, while those at 40 cm depth surfaced 504 times, swimming 403.2 m at an energy cost of 7.4 mg/g/day. Owing to the sustained swimming activity and the consequent fatigue, the test individuals belonging to both groups in all the tested series hang to the surface for a definite interval, repaying the O₂ debt. Observations were also made to assess the duration of hanging to precisely estimate the distance travelled. Irrespective of changes in depths of water, the duration of hanging to surface was only 3.0 hr/day for the feeding groups, while it was as much as 15.5 hr/day for the starving groups. The maximum sustained metabolic level of O.striatus reared in 40 cm depth was equivalent to 1.23 ml O₂/g/hr, which is about 2 times higher than the value reported for the active metabolism of swimming Oncorhynchus nerka at 15°C in Brett's (1964) respirometer. O.striatus reared in 2.5 cm depth fed 32.0 mg and converted 6.7 mg dry food/g live fish/day, while those exposed to the deepest water fed 49.1 mg, but converted only 5.5 mg/g/day. Culturing obligatory air-breathing fishes in shallow waters will be advantageous.     

Mycologie medicale dans l'ouest de la France: Contribution du service de Parasitologie de l'Universite de NANTES (1963–1973)

Résumé Le service de Parasitologie de l'Université de NANTES s'est intéressé aux problèmes de Mycologie hospitalière, d'épidémiologie des mycoses ainsi que d'expérimentation sur les affinités fongiques, à l'échelon régional, et de 1963 à 1973.La contribution clinique a porté essentiellement sur les levuroses étudiées soit au niveau des cavités buccales irradiées, soit chez les malades des services de Réanimation où l'interprétation du rôle pathogène de Candida parapsilosis nécessite des épreuves immunologiques.Nous avons décrit une forme de Blastomycose chéloïdienne à Aureobasidium pullulans.Nos études morphologiques ont surtout porté sur l'observation au microscope électronique à balayage des ultrasculptures présentées par les champignons kératinophiles, ce qui nous a permis de distinguer les différentes espèces du complexe Microsporum gypseum. Il ne semble pourtant pas que cette technique d'observation permette de résoudre tous les problèmes. La conservation des Dermatophytes en eaudistillée par la méthode de Castellani s'est révélée particulièrement remarquable: une souche de M. gypseum a été récupérée après 6 ans de conservation par ce procédé.Notons, en matière d'épidémiologie la prédominance de Trichophyton rubrum sur T. mentagrophytes, survenue récemment: la recrudescence passagère d'Epidermophyton floccosum; la présence d'Arthroderma simii sur une plage. Une étude des champignons kératinophiles telluriques du massif armoricain a porté sur près de 3000 échantillons de terre, ce qui a permis de retrouver, assez rarement d'ailleurs, Arthroderma benhamiae.Nos expérimentations ont porté sur les réponses sérologiques et histologiques de lapins à une imprégnation aspergillaire par instillation intra-trachéale: les résultats obtenus ont été comparés aux examens sérologiques obtenus chez l'homme atteint d'aspergillose. Enfin, nous avons remarqué que le contact levures-cellules sarcomateuses opéré in vitro permet aux levures d'acquérir un pouvoir immunisant antitumoral par emprunt antigénique. La création d'un service de Parasitologie, Mycologie et Immunologie Parasitaire à l'Unité d'Enseignement et de Recherche des Techniques Médicales de NANTES nous a permis non seulement d'aborder les problèmes du diagnostic biologique des mycoses humaines, mais aussi d'entreprendre des enquêtes épidémiologiques dans la région nantaise ainsi que des expériences sur les affinités fongiques.

---

     

The physico-chemical mechanism of mediated transport. I. Facilitated diffusion

On the basis of the currently accepted model for the cell membrane structure, a physico-chemical model for mediated transport is developed and solved for the case of polar non-electrolyte migration through the cell membrane. The model considers the interstitial space defined by the transport protein subunits to be the migration pathway for polar solutes. A Langmuir-type adsorption equilibrium is assumed at the interfaces and a multicomponent diffusion mechanism of solute and water is postulated within the migration pathway, where the polar residues of the transport protein represent another component of the system. Membrane selectivity is governed by the adsorption constants, which are shown to affect strongly the kinetics of transport. Isosmotic transport and the volume change of the cell are important features incorporated in the model, which is shown to fulfill the peculiar properties of facilitated diffusion systems. It is concluded that the same type of pathway can be used for the transport of other polar solutes through existing or induced hydrophilic channels, for which a similar approach is suggested.     

An optimal dietary non-phytate phosphorus level of broilers fed a conventional corn–soybean meal diet from 4 to 6 weeks of age

It is imperative to evaluate precise nutrient requirements of animals in order to optimize productivity and minimize feed cost and nutrient excretions. The current non-phytate phosphorus (NPP) recommendation for broilers is based on the papers published 30 years ago. However, today’s commercial birds are quite different from those before 30 years. Therefore, the present experiment was conducted with growing male broiler chickens to evaluate an optimal dietary NPP level of broiler chickens fed a conventional corn–soybean meal diet from 4 to 6 weeks of age. The 1-day-old chicks were fed corn–soybean meal diet containing 0.39% NPP from 1 to 3 weeks of age. At 22 days of age, 360 birds were selected and randomly allotted by BW to one of 10 dietary treatments with six replicate cages of six birds per cage for each treatment. Birds were fed the P-unsupplemented corn–soybean meal basal diet and the basal diet supplemented with inorganic P as CaHPO₄·H₂O ranging from 0.00% to 0.45% with 0.05% increment from 4 to 6 weeks of age. The dietary NPP levels were 0.09%, 0.14%, 0.20%, 0.24%, 0.30%, 0.34%, 0.38%, 0.45%, 0.49% and 0.54%, respectively, and the dietary Ca level was fixed at 0.90% for all treatments. The results showed that average daily gain, serum inorganic P concentration, tibia bone strength, tibia ash percentage and P percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage and P percentage, middle toe BMC, total body BMC and BMD were affected (P<0.0001) by dietary NPP level, and increased linearly (P<0.0001) and quadratically (P<0.003) as dietary NPP levels increased. Optimal dietary NPP levels estimated based on fitted broken-line models (P<0.0001) of the above indices are 0.21%, 0.29%, 0.29%, 0.29%, 0.29%, 0.31%, 0.29%, 0.30%, 0.27%, 0.29% and 0.28%, respectively. It is suggested that the total body BMC and BMD, and middle toe ash P and BMC might be new, sensitive and non-invasive criteria to evaluate the dietary NPP requirements of broilers. The optimal dietary NPP level would be 0.31% for broiler chickens fed a conventional corn–soybean meal diet from 4 to 6 weeks of age.     

Antibody formation by one or both lymphoid populations present in chimeric marmosets

Development of an isoimmune serum capable of identifying a specific leukocyte antigen in the marmoset, Saguinus fuscicollis illigeri, permitted detection of lymphoid cell chimerism in this species by the cytotoxic test. This reagent was then used to identify the cell population in the chimera responsible for antibody production against a test antigen, sheep red blood cells. Primary in vitro antibody formation as measured by plaque-forming cells with blood leukocytes or splenic lymphocytes of six animals chimeric for the leukocyte antigen, MLA-1, revealed an immune response by both cell types of the chimeric population from three animals and a response by only one cell type in the other three.     

Estrogen target cells. Establishment of a cell line derived from the rat pituitary tumor MtT/F4.

Pretreatment of rabbit kidney cells with cytochalasins B and D (CB, CD) enhanced herpes simplex virus type 2 (HSV-2) DNA infectivity 3- to 6-fold over values obtained using the standard CaCl₂ technique. Cells were pretreated with CB for 4–6 h to achieve infectivity enhancement. A lower concentration of CD, and shorter pretreatment periods, resulted in comparable DNA infectivity. Separate exposure of cells to colchicine, colcemid, or vinblastine increased DNA infectivity 7-, 6-, and 5-fold, respectively, over control values. Additional enhancement was obtained when CD was used together with any one of the aforementioned drugs. Maximal enhancement of HSV-2 DNA infectivity was obtained by pretreating recipient cells with a drug mixture containing colchicine, colcemid, and CD. This treatment maximized infectivity levels 20- to 30-fold over CaCl₂ control values.     

Combined effect of glycerol concentration and cooling velocity on motility and acrosomal integrity of boar spermatozoa frozen in 0.5 ml straws

The interaction of glycerol concentrations of 0-10% and cooling rates from 1 to 1,500 degrees C/min with boar spermatozoa motility and acrosomal integrity (proportion of spermatozoa with normal apical ridge) was studied after thawing 0.5 ml straws at a constant rate. While increasing the glycerol concentration from 0 to 4% progressively improved motility, the percentage of spermatozoa with a normal apical ridge gradually decreased. The magnitudes of the respective changes depended on cooling rate. A peak value of 48.1% and rating 3.8 were obtained in semen protected with 4% glycerol, frozen at 30 degrees C/min. Increasing the glycerol levels above 6% resulted in a gradual decrease in motility. The proportion of spermatozoa with normal apical ridge was highest in semen protected with 0-1% glycerol after cooling at 30 degrees C/min (64.4% and 66.1%, respectively), but at these glycerol concentrations the percentage of motile spermatozoa was low. At the 30 degrees C/min cooling rate, the decline in the proportion of cells with normal apical ridge due to increasing the glycerol levels to 3 and 4% was relatively slow (57.3% and 49.4%, respectively). Cooling at 1 degrees C/min was detrimental to acrosomal integrity, which decreased with increasing glycerol concentration, in contrast to increasing motility, which even at its maximum, remained low. The direct plunging of straws into liquid nitrogen (1,500 degrees C/min) resulted in damaged acrosomes in all spermatozoa with the total loss of motility. Balancing motility and acrosomal integrity, freezing boar semen protected with 3% glycerol by cooling at 30 degrees C/min resulted in optimal survival for boar semen frozen in 0.5 ml French straws.     

The induction of cell-mediated immunity and tolerance to insulin with insulin coupled to syngeneic lymphoid cells

The induction of delayed type hypersensitivity (DTH) and tolerance to DTH against bovine insulin in mice were explored. DTH was induced with insulin in complete Freund's adjuvant (CFA) and was assessed by ear swelling in vivo and by antigen-driven cell proliferation in vitro. Using the concept that thymus cell unresponsiveness is most easily accomplished via antigen on syngeneic membranes, tolerance was induced by iv injection of syngeneic lymphoid cells which had been coupled to insulin with carbodiimide. Mice tolerized with insulin-coupled cells and then sensitized with insulin-CFA had diminished ear swelling in vivo and decreased insulin-driven cell proliferation in vitro. This unresponsiveness was antigen specific but was also inconstant in degree with regard to suppression of ear swelling, most likely because of variability in coupling of insulin to cells. Proliferative responses were more uniformly suppressed, suggesting the possibility that two target cells were being tolerized. Thus, as with other proteins, the biologically active insulin can be used to induce tolerance.     

The ability of nonspecific T-cell stimulators to induce helper-cell-dependent increases in either polyclonal or isotype-restricted Ig production in vivo

In order to delineate the various roles of T cells in B-cell activation, mice were exposed to a variety of specific or nonspecific T-cell stimuli including mitogens, e.g., concanavalin A, adjuvants, e.g., complete Freund's adjuvant, and colchicine plus nonimmunogenic doses of antigen, anti-lymphocyte serum, and pathogens and their spleens analyzed for total class-specific immunoglobulin-secreting cells as indicators of helper cell generation. The results demonstrate that, depending on the mode of stimulation, markedly different Ig-secreting cell response patterns were induced, differing with respect to their kinetics and the isotype induced. In contrast to polyclonal T-cell stimuli such as concanavalin A and 17X lethal malaria which induced increases in all classes of Ig-recruiting cells, injection of many T-cell-activating agents resulted in the selective production of IgG clones in particular IgG 1. Such findings are discussed in terms of the different mechanisms of T-cell help and provide further evidence for functional heterogeneity in the T-helper-cell pool.