How to find your way through the thymus: a practical guide for aspiring T cells

Thymocytes must complete an elaborate developmental program in the thymus to ultimately generate T cells that express functional but neither harmful nor useless TCRs. Each developmental step coincides with dynamic relocation of the thymocytes between anatomically discrete thymic microenvironments, suggesting that thymocytes’ migration is tightly regulated by their developmental status. Chemokines produced by thymic stromal cells and chemokine receptors on the thymocytes play an indispensable role in guiding developing thymocytes into the different microenvironments. In addition to long-range migration, chemokines increase the thymocytes’ motility, enhancing their interaction with stromal cells. During the past several years, much progress has been made to determine the various signals that guide thymocytes on their journey within the thymus. In this review, we summarize the progress in identifying chemokines and other chemoattractant signals that direct intrathymic migration. Furthermore, we discuss the recent advances of two-photon microscopy in determining dynamic motility and interaction behavior of thymocytes within distinct compartments to provide a better understanding of the relationship between thymocyte motility and development.     

A prostaglandin-like activity in small intestine and postirradiation gastrointestional syndrome.

A correlation between the postirradiation increase of the small intestine motility and the prostaglandin-like activity in this organ during gastrointestional syndrome was observed. Indomethacin decreased the elevated motility of intestine and reduced the prostaglandin-like activity in this syndrome.     

Decrease in motor activity - an early symptom in the course of experimental allergic encephalomyelitis (EAE).

Motor activity has been followed in rats during an experimental allergic encephalomyelitis (EAE). The disease was produced by transfer of lymph node cells from sensitized syngenic donors. Small and large movements were permanently registered by an electric activity meter. It could be demonstrated that a decrease of the motility is an early symptome of the disease. Therefore the measurement of the motoric activity might be a useful parameter in the classification of EAE.     

A prostaglandin-like activity in small intestine and postirradiation gastrointestinal syndrome

Summary A correlation between the postirradiation increase of the small intestine motility and the prostaglandin-like activity in this organ during gastrointestinal syndrome was observed. Indomethacin decreased the elevated motility of intestine and reduced the prostaglandin-like activity in this syndrome.Acknowledgments. The work was supported by the Polish Academy of Sciences.     

Prolongation of the duration of motility and fertilizing ability of rainbow trout spermatozoa by the addition of theophylline to the dilution medium

After rainbow Trout sperm were diluted in 0.01 and 0.001 M theophylline media, motility and fertilizing ability were prolonged as compared to the control media without theophylline. However, the motility observed was lower and of a different type than normal motility. This suggests that other factors besides cyclic nucleotides intervene in the motility of Trout spermatozoa.     

The effects of sodium and amiloride on the motility of the caudal epididymal spermatozoa of the rat

Summary The forward motility of the rat caudal epididymal spermatozoa has been studied in different Na⁺ concentrations. When spermatozoa were suspended in a completely Na⁺-free solution, the forward motility suffered a progressive fall and after 3 h was completely suppressed. This effect was fully reversible on resuspending the spermatozoa in a solution containing Na⁺. Amiloride caused a fall in motility and the effect was similar to that of Na⁺ removal. The inhibition by amiloride of the motility was concentration dependent and the dose response curve showed an IC₅₀-value of about 5×10^–5 M. The role of Na⁺ influx in the maintenance of sperm motility was discussed.This work was supported by the World Health Organization.The technical assistance of Mr C.M. Li and the gift of amiloride from Merck, Sharp and Dohme are gratefully acknowledged.     

Defining motility in the <Emphasis Type="Italic">Staphylococci</Emphasis>

The ability of bacteria to move is critical for their survival in diverse environments and multiple ways have evolved to achieve this. Two forms of motility have recently been described for Staphylococcus aureus, an organism previously considered to be non-motile. One form is called spreading, which is a type of sliding motility and the second form involves comet formation, which has many observable characteristics associated with gliding motility. Darting motility has also been observed in Staphylococcus epidermidis. This review describes how motility is defined and how we distinguish between passive and active motility. We discuss the characteristics of the various forms of Staphylococci motility, the molecular mechanisms involved and the potential future research directions.     

Decrease in motor activity — an early symptom in the course of experimental allergic encephalomyelitis (EAE)

Summary Motor activity has been followed in rats during an experimental allergic encephalomyelitis (EAE). The disease was produced by transfer of lymph node cells from sensitized syngenic donors. Small and large movements were permanently registered by an electric activity meter. It could be demonstrated that a decrease of the motility is an early symptome of the disease. Therefore the measurement of the motoric activity might be a useful parameter in the classification of EAE.To whom reprint requests should be addressed.Acknowledgments. We thank ABFARAD Nyborgsgränd 1, 12634 Hägersten (Sweden) for making the Animex activity meter available to us. The experiments were supported by the Deutsche Forschungsgemeinschaft.     

Beziehungen zwischen Funktion und Stoffwechsel des Zentralnervensystems nach Pervitin

Summary The ATP- and coenzyme-A-content increases in the brain of white mice during excitation produced by Pervitin (2–3µg/g bodyweight) proportional to motility, rate of respiration and oxygen-uptake. These facts, observed in this almost physiological excitation, are contrary to the reduction of the energy-rich phosphates in the brain during convulsions.     

Effect of benzatropine on the O-methylation of striatal dopamine]

After treatment by nialamid, benztropine administered to Rats produced an increase in the level of 3-O-methyldopamine in the corpus striatum. It produced a slight increase in the level of striatal dopamine and no change in the level of norepinephrine. The monoamine oxydase and catechol-O-methyltransferase activities of remaining brain showed no variations by benztropine. The results suggest the possible involvement of striatal dopamine and its extraneuronally catabolism in the antiparkinsonian effect of benztropine.     

Effects of aresenite and oxamate on the in vitro functional activity of estrogen-dominated rate uterine horns.

Arsenite but not oxamate produce in vitro a distinct depression of estrogen-dominated uterine motility, both in the absence of substrate as well as in the presence of exogenous glucose or lactate. The addition of oxamate to preparations suspended in a medium with lactate as the sole external substrate ameliorates the depression of uterine motility elicited by arsenic.     

Disruption of mitochondrial function as the basis of the trypanocidal effect of trifluoperazine on Trypanosoma cruzi.

The tricyclic anti-calmodulin drug trifluoperazine (TFP) inhibited growth and motility of epimastigotes of Trypanosoma cruzi, at concentrations lower than 100 microM, and motility and infectivity of the bloodstream trypomastigote form at 200 microM. Electron microscopy of TFP-treated epimastigotes showed that the major effect was at the mitochondrial level, with gross swelling and disorganization. The oligomycin-sensitive, mitochondrial ATPase was completely inhibited by 20 microM TFP, and the same drug concentration caused a 60% decrease in intracellular ATP content. The results suggest that the trypanocidal effect of TFP may be related more to mitochondrial damage than to the well-known anticalmodulin effect of the drug.     

Rosette formation by human T and B lymphocytes in the presence of adrenergic and cholinergic drugs.

It was shown that adrenergic drugs, which increase the intracellular levels of cAMP, inhibit the rosette formation by T-lymphocytes, but stimulate the rosettes produced by B-lymphocytes. Cholinergic drugs, which increase the levels of cGMP, on the contrary, stimulate the formation of rosettes by T-lymphocytes but inhibit those produced by B-lymphocytes.     

MSAP enhances migration of C6 glioma cells through phosphorylation of the myosin regulatory light chain

A key regulatory mechanism in cell motility is the control of myosin activity, which in non-muscle cells is determined by phosphorylation of the myosin regulatory light chain (MRLC). Here we show that MRLC-interacting protein (MIR)-interacting saposin-like protein (MSAP) enhances cell spreading in fibroblasts and migration of rat C6 glioma cells through increases in MRLC phosphorylation. Overexpression of MSAP enhanced the motility of glioma cells measured in matrigel invasion chambers and using a scratch assay. Downregulation of MSAP by RNA interference significantly decreased glioma cell migration and phosphorylation of MRLC. Inhibition of the corresponding MRLC kinase by ML-7 did not affect migration of MSAP-overexpressing cells. The present results show that MSAP controls glioma cell migration via enhancement of MRLC phosphorylation. This effect is independent of the activity of MRLC kinase. Thus, MSAP is a novel modulator of cell motility that influences migration of glioma cells and possibly other tumors.Received 9 February 2005; received after revision 2 March 2005; accepted 21 March 2005     

The effect of corticotropin-releasing factor and pro-opiomelanocortin-derived peptides on the phagocytosis of molluscan hemocytes

The effect of corticotropin-releasing factor (CRF) and pro-opiomelanocortin (POMC)-derived peptides on hemocyte phagocytosis in two molluscs,Planorbarius corneus andViviparus ater was studied. The peptides and related fragments examined are those which have been shown to influence hemocyte motility in the two species. The results obtained revealed that the effects on phagocytosis are not directly correlated with previous findings on cell motility. Furthermore, the mode of action of an individual peptide could be species-specific and dose-dependent. The relationships between peptides, locomotion and phagocytosis in these molluscs are discussed.     

Effects of retinoic acid on the fibrinolytic activity of HL 60 human promyelocytic leukemia cells

Summary Fibrinolytic activity of HL 60 human leukemic cells was found to increase in parallel with myeloid differentiation following retinoic acid but not dimethylsulfoxide treatment. However, both retinoic acid and dimethylsulfoxide produced an increase in acid phosphatase and a decrease in muramidase.     

Two-step acquisition of motility by insect spermatozoa

High motility of eupyrene sperm of a grasshopper (Omocestus ventralis) was induced by cAMP. Both trypsin and cAMP were necessary for high motility of eupyrene sperm of three other species of grasshoppers. The same was found for apyrene sperm of the silkmoth,Bombyx mori, when they had been wahsed free from seminal plasma. On the other hand, in locusts (Locusta migratoria), in which the yellow gland has high Arg-C endopeptidase activity, sperm motility was induced by trypsin, like that of apyrene sperm of Lepidoptera. Thus in these two orders of Insecta, sperm motility appears to be induced by the same two-step process: the first step by Arg-C endopeptidase, and the second by cAMP.     

Electrically-induced mechanical activity of the isolated guinea-pig sciatic nerve. Influences of calcium and anoxia

Summary The electrically induced motility of isolated segments of guinea-pig sciatic nerves is reported. This motility was characterized by waves of tensional variations. The removal of Ca²⁺ from the suspending solution, the addition of EDTA as well as anoxia, resulted in a decrement of tension accompanied by a prolongued duration of the cycles of mechanical activity.This work was supported by grant 6638, from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina (C.O.N.I.C.E.T.).     

Rosette formation by human T and B lymphocytes in the presence of adrenergic and cholinergic drugs

Summary It was shown that adrenergic drugs, which increase the intracellular levels of cAMP, inhibit the rosette formation by T-lymphocytes, but stimulate the rosettes produced by B-lymphocytes. Cholinergic drugs, which increase the levels of cGMP, on the contrary, stimulate the formation of rosettes by T-lymphocytes but inhibit those produced by B-lymphocytes.Acknowledgments. This investigation was supported by Grant from National Council for Scientific and Technological Development (CNPq), Rio de Janeiro, Brazil.     

The hypothalamic somatostatinergic pathways mediate feeding behavior in the rat

The level of somatostatin in the hypothalamus was higher in satiated rats than in hungry rats. Elevating hypothalamic somatostatin levels by administering somatostatin into the hypothalamus produced a decrease in food intake, whereas lowering hypothalamic somatostatin levels by administering cysteamine into the peritoneal cavity produced an increase in food intake in rats.