Development of post-hatching melatonin rhythm in zebra finches (Poephila guttata)

We examined levels of melatonin in the pineal, eyes and plasma over a 24 h period during development in the altricial zebra finch. Beginning as early as 2 days after hatching there was a distinct 24 h rhythm in melatonin in the pineal and plasma. Beginning at day seven after hatching there was also a 24 h rhythm present in the eyes. In the pineal and eyes the amplitude of the 24 h rhythm increased with age. In contrast, the amplitude of the plasma melatonin rhythm at 2 days was already within the range of adults and did not increase with age. These results confirm and expand earlier findings in the European starling and parallel those from precocial birds indicating that the circadian system is already competent at or shortly after hatching even in atricial birds.     

Sexual differences in the development of plasma thyroxine levels in the embryo and young chick]

Plasma thyroxine (T4) levels were separately ascertained in male and female embryo and young chicken from the 12th day of incubation till the 4th day after hatching by the thyroxine binding globulin technique. In both sexes, plasma T4 reach a peak the 20th day of incubation, but values are significantly higher in females. A sharp decrease occurred thereafter, plasma T4 tending toward adult values the 4th day after hatching.     

Effect of the substratum on the growth of CFU-c in continuous marrow culture

Cellular and Molecular Life Sciences - The effect of the substratum on the maintenance of granulocyte-macrophage progenitors (CFU-c) was studied in continuous mouse marrow culture. Glass and...     

Imprinting of the Peking duck (Anas platyrhynchos) and dependence on exposure to light during ontogenesis

Embryos of Peking ducks were either incubated in complete darkness up t o hatching or were put into light one week before hatching. Control embryos were incubated under dim light conditions which corresponded broadly to the natural conditions. Under standardized imprinting conditions the controls and both groups of the light deprived ducklings showed the 'following response'. Most of the dark-incubated embryos, however, did not distinguish between imprinting and test objects of different shapes. Since most of the embryos kept in darkness only for 21 days also failed to develop the capacity for shape discrimination, there is apparently a critical period for light influences on the development of this capacity at some time during the early prenatal period.     

Demonstration of Yersinia pseudotuberculosis in in cultivated soils]

The bacteriological analysis of 37 pools of cultivated soils collected in a limited area in the Parisian district permits the isolation of 14 strains of Y. pseudotuberculosis: 9 strains are of serotype II, 3 of serotype I, 1 of serotype III, and of serotype IV. This diversity contrasts with the prevalence of serotype I in infections of man and animals and the scarcity of type III and IV in these species. The abundance of our isolates is in favour of a large distribution of the germ in this substratum, which can be considered as a potential contamination source.     

Relationship between regeneration of cell surface glycoproteins in trypsin-treated chick embryo fibroblasts and cell adhesion to the substratum

The ability of cells to adhere to a substratum was altered by treatment with trypsin but was restored after a 1.5-h culture. A concomitant incorporation of [3H] leucine and [14C] glucosamine in the trypsin-sensitive cell surface glycoproteins was observed and almost reached a plateau within 1.50 h following the treatment with trypsin.     

The Bursa of Fabricius isolated from intestinal flow in chicken at hatching: The surgical technique

Summary A proposed operational technique is described whereby the intestinal flow from the Bursa of Fabricius in chickens at hatching is excluded.     

Placing the activity rhythm in Araneus cornutus]

Araneus cornutus spiderling activities recorded from hatching to scattering show a particular distribution of the general motor activity over a 24-hour period. More motor activity is first observed during the light sequence, while at a nocturnal activity distribution appears after the 2nd nymphean ecdysis.     

Formation of cutaneous nerve trunks in the chick. Ultrastructural and quantitative analysis]

In chick skin structuration of nervous trunks takes place at 14-15 days of incubation, at the time of formation of the adult pattern of cutaneous innervation. At this same stage, myelogenesis begins, but develops mainly after hatching: only 4% of axons are myelinated at hatching, 40% in 6-week old Chickens and 60% in adults. This "critical" stage (14-15 days of incubation) apparently corresponds to the stabilization of cutaneous nerve supply.     

Effects of gamma irradiation on dermal equivalents in vitro

Summary Dermal equivalents (DE), collagen lattices, were produced in vitro and used as a model for studying the possible role of a pure population of fibroblasts in post-radiotherapeutic dermal fibrosis. Single doses of gamma irradiation induced a partial inhibition of the collagen lattice retraction and of protein synthesis. The collagen production was less inhibited than was synthesis of non-collagen protein, which resulted in an increase of the relative amount of collagen synthesized by irradiated fibroblasts. These data suggest that gamma irradiation might be able to select some fibroblast clones able to produce increasing amounts of collagen. This selection process could be involved in the development of tissue fibrosis after therapeutic radiation.     

Effects of gamma irradiation on dermal equivalents in vitro

Dermal equivalents (DE), collagen lattices, were produced in vitro and used as a model for studying the possible role of a pure population of fibroblasts in post-radiotherapeutic dermal fibrosis. Single doses of gamma irradiation induced a partial inhibition of the collagen lattice retraction and of protein synthesis. The collagen production was less inhibited than was synthesis of non-collagen protein, which resulted in an increase of the relative amount of collagen synthesized by irradiated fibroblasts. These data suggest that gamma irradiation might be able to select some fibroblast clones able to produce increasing amounts of collagen. This selection process could be involved in the development of tissue fibrosis after therapeutic radiation.     

The implantation of sepharose beads in mouse livers as an aid in the study of hepatic schistosomal fibrosis

Summary An experimental model of schistosomal portal fibrosis is described. Sepharose beads the size of schistosome eggs, loaded or not with soluble egg antigen (SEA) fromSchistosoma mansoni, are injected into the coecal vein of C3H/Sn mice and become embolized in the liver. Only SEA-coated beads evoke a granulomatous reaction; this is enhanced by simultaneous priming of the mice with spleen cells fromSchistosoma mansoni-infected syngeneic animals. The fibrosis, which ensues around the beads, is stable and is much more evident after priming. Preliminary collagen tissue immunotyping reveals the presence of collagen deposits of types I and III collagen. Type IV collagen remains unchanged in the portal tracts. The model appears to be well suited for studies of the pathogenesis of portal fibrosis.This work was supported by a contract from INSERM (Action Spéciale No 3).     

The effect of cyclic cytidine 3',5'-monophosphate (cCMP) on the in vitro development, hatching and attachment of the mouse blastocyst

The in vitro development and attachment of hatched mouse blastocysts on the untreated substratum was enhanced by 10 microM dibutyryl cCMP (dbcCMP). The result suggests that cCMP has an effect on embryonic development and on the blastocyst attachment process.     

Collagen in aging muscles.

The salt, acid and insoluble collagen fractions were estimated in red, white and cardiac muscles of 10-, 15- and 20-month-old albino rats. The total collagen level with reference to total proteins is more in red than in white and cardiac muscle. Accumulation of more of insoluble collagen and decrease in salt extractable collagen is seen in all three muscles with aging.     

Chemotaxis is not a special case of haptotaxis

Serum peptides containing classical anaphylatoxin (CAT) produce marked chemotatic orientation of human neutrophil granulocytes without modifying cell attachment to the substratum. Furthermore gradients of adhesion produced with gammaglobulins fail to induce morphological orientation of neutrophils. The results suggest that chemotaxis is not a special case of haptotaxis.     

Renewal of pulmonary insoluble collagen in the adult rat]

Study of polymeric pulmonary collagen in adult Rats showed that about 70% of collagen was renewed with a half-time equal to 525 days. This value is to be compared with the median life-span of this rat strain, 890 days. The remaining 30% of polymeric collagen is renewed with a shorter half time, about 30 days.     

Differential regulation of collagen types I and III expression in cardiac fibroblasts by AGEs through TRB3/MAPK signaling pathway

Advanced glycation end products (AGEs) play an important role in collagen deposition in diabetic cardiomyopathy. TRB3, a mammalian homolog of Drosophila tribbles, functions to increase glucose intolerance and regulates cell proliferation. We demonstrated that AGEs induce collagen type I expression but inhibit collagen type III expression, accompanied by increased TRB3 expression. Furthermore, the collagen type I induced byAGEs was down-regulated after inhibition of ERK and p38-MAPK, the collagen type III reduced by AGEs was up-regulated after inhibition of ERK. The expression of collagen types I and III regulated by AGEs through MAPK was partly reversed after treatment with TRB3 siRNA. It suggests that the TRB3/MAPK signaling pathway participates in the regulation of collagen types I and III by AGEs and may provide new therapeutic strategies for diabetic cardiomyopathy. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 08 May 2008; received after revision 25 June 2008; accepted 22 July 2008 M. Tang, M. Zhong: These two authors contributed equally to this work.     

Relationship between regeneration of cell surface glycoproteins in trypsin-treated chick embryo fibroblasts and cell adhesion to the substratum

Summary The ability of cells to adhere to a substratum was altered by treatment with trypsin but was restored after a 1.5-h culture. A concomitant incorporation of [³H] leucine and [⁴C] glucosamine in the trypsin-sensitive cell surface glycoproteins was observed and almost reached a plateau within 1.50 h following the treatment with trypsin.     

Amoeboid movement: A review and proposal of a ‘membrane ratchet’ model

Summary Diverse cell types, including Amoebae, leukocytes, embryonic cells and tumour cells move about on solid surfaces to accomplish such activities as feeding, bacterial destruction, embryological development and metastasis. Theories of the mechanism of this movement are reviewed and a model is proposed which invokes the existence of specific, laterally mobile, transmembranous structures in the cell membrane, which are reversibly adhesive for both the contractile apparatus of the cell internally, and the substratum externally. By this model, the movement of all these cell types can be explained.     

The effect of adhesion on survival and growth of microorganisms

Summary Adhesion of microorganisms to solid surfaces or water/air interfaces can significantly influence cellular metabolic activity, development and viability. Attachment is of advantage particularly for organisms growing under oligotrophic or otherwise extreme conditions. However, the ability to detach and migrate is of vital importance when prevailing conditions become too harsh or in situations of population explosion.Adhesion can cause alterations in the physical and chemical properties of substratum surfaces as well, by means of degradation, aggregation, emulsification etc.