Relationships between tail-flicking, morphology, and body condition in Moorhens

ABSTRACT.   Prey-predator communication of alertness has been reported for Moorhens ( Gallinula chloropus ) and other species of birds. Because ability to flee is probably related to body condition, healthy potential prey may behave more conspicuously to send predators an unambiguous message. Moorhens have a contrasting rump patch that is flashed by rapid tail-flicking. During two winter months, we observed sex-related differences in the rate of tail-flicking. Females tail-flicked at a faster rate than males, and more vigilant and more symmetrical males tail-flicked faster. The rate of tail-flicking was negatively correlated to the heterophil/lymphocyte ratio in both sexes and positively correlated to hematocrit and albumin/globulin ratio in females. These results suggest that male and female Moorhens in better physical condition tail-flick at a faster rate and support the pursuit deterrent hypothesis, with healthy individuals appearing to inform predators that they would be difficult to capture.     

Cellular cadmium distribution in the common winkle, Littorina littorea (L.) determined by X-ray microprobe analysis and histochemistry

Various tissues of common winkles, Littorina littorea (L.), experimentally exposed to cadmium (Cd) chloride were examined using light and electron microscopy and their elemental composition determined by X-ray microanalysis and histochemistry. Membrane granules in gill epithelial cells with paddle cilia contain carbonates, phosphates and sulphides associated with different cations in different types of granules. Traces of Cd have been found only in those granules containing sulphur and iron. Nephrocytes also contain small amounts of this metal in the cytoplasm of excretory cells. X-ray microanalysis reveals that concretions of basophilic cells are minor sites for Cd sequestration while BTAN-ASSG stain for unbound Cd indicates that most of the Cd is located within the lysosomes of digestive cells in association with proteins. Low amounts of the metal have been evidenced in the granules of epithelial mantle cells rich in sulphur. The results also indicate that hemocytes contain granules of calcium phosphate and iron sulphide. Cd is also associated to sulphur rather than to phosphate. These hemocytes may act as Cd carrier from gills to kidney and digestive gland. A hypothetical pathway for Cd accumulation and detoxification is suggested.     

Fine structure of the nephridial muscle layer cells of Phascolosoma granulatum (Sipuncula)

The nephridial muscle layer of Phascolosoma granulatum consists of a network of longitudinal and circular cells separated by connective tissue matrix. The muscle fibers are densely packed with thick and thin myofilaments, among which are scattered cytoplasmic dense bodies. The nucleus and noncontractile cytoplasmic organelles occupy a lateral projection from the contractile portion of the fiber. Cytoplasmic dense bodies are the result of a clustering of an indeterminate number of the thin actin filaments that fill the cytoplasm between thick filaments. Attached to the cytoplasmic face of the cell membrane are membrane-associated electron-dense plaques. These sites are linked to the contractile myofilaments by narrow filamentous bridges. Extracellular narrow filaments extend from these plaques to collagen fibers of the connective tissue matrix. Differences in length of the dense plaques may be related to differences in thick myofilament diameter in three types of muscle fiber, types A, B and C, statistically distinguished by mean fiber size differences. The plaques may serve as connecting links for the transmission of tension from contractile units to the connective tissue of the muscle layer. © 1993 Wiley-Liss, Inc.     

Histochemistry and elemental composition of the stomach cells in Littorina littorea (L.)

The present work deals with the histochemical, histoenzymological and micro-analytical study of the stomach of Littorina Littorea (L.). The results suggest the existence of intracellular digestion within the stomach cells. Thus, the occurrence of lysosomes in the mid-cytoplasm of stomach cells has been revealed by demonstration beta-glucuronidase activity in cryostat sections of frozen tissues. Other enzymatic activities have been proved with the same tissues. Accordingly, the results on lipid and pigment histochemistry indicate a certain digestion in this cell type. Mucocytes show a protective role for the epithelium, their main secretions being acid MPS. The elemental composition of electron dense concretions from the stomach cells indicate the presence of very high amounts of iron associated to lower peaks for sulphur, phosphorous and other cations found as calcium, copper and zinc.     

Validation of a planimetric procedure to quantify stress in Littorina littorea (Gastropoda: Mollusca): is it independent of the reproductive cycle?

This study forms part of a larger project in which five planimetric parameters have been used to study changes in the digestive epithelium of Littorina littorea under different environmental and physiological conditions. Our aim was to examine the effect of the reproductive cycle on these parameters in order to assess their usefulness as indicators of stress. A one way anova shows that the absolute parameters of mean epithelial thickness (MET), mean diverticulum radius (MDR) and mean luminal radius (MLR) vary significantly depending on the time of the year. This variation is highly correlated to the amount of digestive tissue present and hence negatively correlated to the reproductive state because gonad and digestive tissue volume are inversely related. Consequently, these parameters are not good indicators of stress. However, whereas the absolute size of the digestive acinus varies with the reproductive state of the animal, the MET, MDR and MLR retain the same proportions and therefore the ratios MET/MDR and MLR/MET remain constant. This makes them useful indicators of stress because they are independent of intrinsic variables such as the reproductive cycle.     

The reversible effect of colchicine on the taste bud cells of the central circumvallate papilla in the rat

Summary It is believed that differentiation and maintenance of taste buds in vertebrates is dependent on the trophic function of their sensory nerve supply. In the present work colchicine was injected into the circumvallate papilla of the rat. This produced a reversible blockade of neuroplasmic transport and disappearance of taste buds. Colchicine inhibited the further differentiation of bud cells, but apparently did not change the life cycle of the cells present already at the time of injection. It is speculated that the neurotrophic factors in this particular cell system are effective to induce cell differentiation only.This work was supported by CAIT Grant No 1776     

Gene frequencies of caprine αs1-casein polymorphism in Spanish goat breeds

Using electrophoretic techniques (PAGE-SDS and IEF), we report allelic frequencies of caprine α_s1-casein (Cn) locus in four Spanish milking breeds: Murciana-Granadina, Malagueña, Payoya and Canaria. The E allele (intermediate content of α_s1-Cn in milk) was predominant in dairy breeds Murciana-Granadina, E:0.59; Malagueña, E:0.65 and Payoya, E:0.76, while alleles A and B (high content of α_s1-Cn) were more frequent in the Canaria dairy breed (A:0.28 and B:0.32). Among the Spanish breeds, Canaria represents a particular case where 60% of the alleles were of the high type (A and B). The ethnical group Canaria Palmera was particularly high in the frequency of alleles A and B (91%) very similar to the Italian Garganica breed (98%). The low frequency of F allele (reduced level of α_s1-Cn) in Spanish breeds (Murciana-Granadina, F:0.08; Malagueña, F:0.04; Payoya, F:0.00 and Canaria, F: and Saanen breeds. It is important to note that in the Payoya breed no low or null alleles (F, D, 0) were detected. It seems unlikely that genetic selection for milk production has had a significant influence in determining the α_s1-Cn allelic distribution in goat populations. The direct relationship existing between these allelic variants and differences in the Cn content and in the physico-chemical properties of milk, can be used as a tool in the improvement of milk processing quality and cheese yields of Spanish milking breeds.