Search results for " zoology"
showing 10 items of 2242 documents
Pheromones linked to sexual behaviors excite the appetitive phase of feeding behavior of Aplysia fasciata II. Excitation of C-PR, a neuron involved i…
1998
Pheromones presumably released by conspecifics amplify both the appetitive and the consummatory components of feeding in Aplysia. These effects can be mimicked by administering homogenate of the large hermaphroditic duct containing atrial gland tissue, as well as peptides from the bag cells. Identified cerebro-pedal regulator (C-PR) neuron is thought to command various behaviors that comprise the appetitive phase of feeding. In a reduced preparation, we investigated the effects on the C-PR of applying these substances to the rhinophores, the sensory organs which detect pheromones. Stimuli that excite feeding in the animal were also found to affect the C-PR. Large hermaphroditic duct homogen…
Connection between body condition score, chemical characteristics of body and reproductive traits of rabbit does.
2008
Abstract Body condition scoring (BCS) is widely used to evaluate the nutritional status of livestock (cows, ewes, sows). In intensive systems, rabbit does are generally inseminated 11 days post partum and, due to a hormonal antagonism and an energy deficit caused by concurrent lactation and pregnancy, they show low fertility. The aim of this investigation was to assess an in vivo method for scoring the body condition of does by verifying the association with the body fat depots, the chemical composition of body tissues, the ovarian status, the hormonal response and the reproductive performance. The evaluation of BCS, involving 66 multiparous lactating does inseminated at 11 days post partum…
Geschlecht und Gender in der Medizin
2005
Gender specific medicine is a part of gender-research, which has been insufficiently considered up to the present in medicine, sanitation and politics. Part of the scientific medicine simply ignores the knowledge that menand women are different in feeling, thinking and social acting without any question. Doctors often incline to treat all their patients as if there was just one gender: i. e. the male one. It is without dispute that men and women vastly suffer from the same diseases, but they often go through them quite differently. The female body seems to work differently from the male one in nearly all respects - starting with the brain, going on with the heart, cardiovascular, lungs, sto…
Behaviour influences cholesterol plasma levels in a pig model
2012
Little is known about the relationship between feed intake behaviour and cholesterol levels in humans. This can be attributed to the fact that feed intake behaviour in humans is difficult to assess. The relationships between feed intake, feed efficiency and feed intake behaviour, and cholesterol and triglyceride levels were investigated at an average age of 187 days, in a pig model consisting of 202 Duroc barrows. Feed intake and feed intake behaviour were recorded individually and daily by means of an electronic identification system. Animals with high levels of total cholesterol also had high levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol and triglycer…
The toxic and lethal effects of the trehalase inhibitor trehazolin in locusts are caused by hypoglycaemia
2003
SUMMARY The main blood sugar of locusts is trehalose, which is hydrolysed to two glucose units by trehalase. Homogenates of locust flight muscles are rich in trehalase activity, which is bound to membranes. A minor fraction of trehalase is in an overt form while the remainder is latent, i.e. active only after impairing membrane integrity. Trehazolin, an antibiotic pseudosaccharide,inhibits locust flight muscle trehalase with apparent Ki-and EC50 values of 10–8 mol l–1and 10–7 mol l–1, respectively. Trehazolin is insecticidal: 50 μg injected into locusts completely and selectively blocked the overt form of muscle trehalase (with little effect on latent activity) and killed 50% of the insects…
Presence of thyroid hormones in ascidian larvae and their involvement in metamorphosis
2001
In this study we investigated the presence and localization of thyroxine in Ciona intestinalis larvae and its involvement in metamorphosis. To date, the mechanisms regulating the metamorphosis of ascidians remain largely unknown. In vivo treatment of swimming larvae with exogenous L-thyroxine and thiourea, and in vitro experiments utilizing high performance liquid chromatography, radioimmunoassay, and immunoperoxidase staining demonstrate the presence of thyroxine at the larval stage. This suggests that this hormone may participate in the control of metamorphosis and thus play a different role from that observed in adults.
Social control of testicular steroidogenic capacities in the Siamese fighting fishBetta splendens Regan
1987
Male Siamese fighting fish (Betta splendens Regan) of the veiltail variety were raised. At the age of 4 ½ months they were either isolated or community-housed for 2 ½ months. After that time the relative fin lengths were determined, and the in vitro metabolism of testosterone by the testes of the fishes was investigated. Community-housed specimens had shorter fins than the isolated males. Their testes formed less 11-oxy- and more 5β-steroids than those of the isolated males. This difference was even larger when high- and low-ranking community-based specimens were compared. The appearance of low-ranking males resembled that of females, and the main products of their testes were 5β-reduced st…
Effects of juvenile hormone analogues upon soldier differentiation in the termite Reticulitermes santonensis (Rhinotermitidae, Heterotermitinae).
2018
Under the influence of juvenile hormone analogues (JHAs), termite workers are induced to differentiate into soldiers. In Reticulitermes santonensis, such induced differentiation is often incomplete, resulting in intercaste production. The morphology of the structures most affected during differentiation was analyzed descriptively and biometrically in normal workers, presoldiers, and soldiers, and in experimental intercastes. We observed that intercastes form a morphological and biometrical continuum between workers and presoldiers (presoldier intercastes), and between presoldiers and soldiers (soldier intercastes). We also compared the biochemistry of the normal individuals and of the inter…
Specific, concentration-dependent uptake of vitellin by the oocytes ofNereis virens (Annelida, Polychaeta) in vitro
1991
One purpose of this study was the development of methods for radioactive labeling and handling of the yolk protein of Nereis virens, another, the utilization of this tracer in nereid oocyte cultures to describe the kinetics and specificity of yolk protein uptake. Accumulation of labeled yolk protein by growing oocytes is linear over time, specific for yolk protein, and dependent on tracer concentration in the medium. Incorporation of yolk protein follows saturation kinetics which allows us to reproducibly determine the characteristics of this process. The apparent KM of ∼ 1 × 10−8 M indicates the high affinity of the transport system; the Vmax (160–400 pg protein/day × oocyte) reveals that …
Identification of the yolk receptor protein in oocytes of Nereis virens (Annelida, Polychaeta) and comparison with the locust vitellogenin receptor
1992
In oviparous animals large amounts of yolk proteins of extraovarian origin are accumulated by developing oocytes during vitellogenesis. The yolk protein precursors, the vitellogenins (VTG), are transported into the oocytes by receptor-mediated endocytosis. In oocytes of the polychaetous annelid, Nereis virens, the receptor protein for VTG was visualized by ligand blotting studies as a protein with an apparent molecular mass of 190 kDa under non-reducing conditions. Anti-Locusta VTG receptor antibodies recognize the Nereis VTG receptor protein. The Nereis VTG receptor protein binds Locusta and Schistocerca VTG; the VTG receptor proteins of both locust species bind the Nereis vitellin. These …