Evaluation of conservation status of Lactoris fernandeziana Philippi (Lactoridaceae) in Chile

The Juan Fernández Archipelago is located 667 km (about 360 nautical miles) west of central Chile (33° S). It is composed of three islands: Robinson Crusoe, Santa Clara and Alejandro Selkirk. Since its discovery in 1574, the islands have been exposed to strong anthropogenic disturbance as a product of colonization. The vascular flora presents a high degree of endemism. Among the Magnoliophyta, 68% of the species are endemic, 15% of the genera and the monotypic family, Lactoridaceae, has only one species, Lactoris fernandeziana, Phil., which is found exclusively on Robinson Crusoe island. This species is a shrub which has been catalogued as extremely rare. More than 960 individuals of Lactoris fernandeziana, over 30 cm in height, were found in 14 localities. The height structure of the individuals suggests a species in recovery. In germination tests under experimental conditions the species shows a light requirement; seedling establishment was difficult and all individuals died within six months. Results are discussed in the light of the conservation measures undertaken by the administration of the Juan Fernández Archipelago National Park. Further studies on the population dynamics and the genetic structure of L. fernandeziana are needed to assure its conservation.     

An ultrastructural approach to feeding behaviour in Philodina roseola and Brachionus calyciflorus (rotifers) III. Cilia and muscles. Conclusions

The orientation of the cilia pseudotrochus is controlled by muscles inserted on their rootlets. The peculiar structures of buccal and pharyngeal cilia are described: their beating leads the food towards the mastax. The circular and longitudinal muscles of the buccal funnel allow peristaltic movements and probably the rejection of food items not accepted by the mastax receptors.     

Effects of prolonged treatment with diltiazem on pituitary secretion of luteinizing hormone, follicle-stimulating hormone, thyrotropin and prolactin.

In previous studies it has been observed that acute administration or short-term treatment with calcium channel blockers can influence the secretion of some pituitary hormones. In this study, we have examined the effect of the long-term administration of diltiazem on luteinizing-hormone (LH), follicle-stimulating hormone (FSH), thyrotropin (TSH) and prolactin (PRL) levels under basal conditions and after gonadotropin-releasing hormone (GnRH)/thyrotropin-releasing-hormone (TRH) stimulation in 12 subjects affected by cardiovascular diseases who were treated with diltiazem (60 mg 3 times/day per os) for more than 6 months and in 12 healthy volunteers of the same age. The basal levels of the studied hormones were similar in the two groups. In both the treated patients and the control subjects, a statistically significant increase (p < 0.01) in LH, FSH, TSH and PRL levels was observed after GnRH/TRH administration. Comparing the respective areas under the LH, FSH, TSH and PRL response curves between the two groups did not present any statistically significant difference. These findings indicate that long-term therapy with diltiazem does not alter pituitary hormone secretion.     

Kinetic characteristics of microsomal NAD-glycohydrolase natural and solubilized with a non-ionic surface-active substance

Microsomal rat spleen NAD-glycohydrolase was solubilized by Nonidet P40. The solubilized enzyme shows Nicotinamide inhibition and pH dependence at the same extent as unsolubilized microsomal one. It differs from the latter in having a higher affinity for NAD and NADP, and in showing two peaks, instead of one, on electrofocusing: the former with a pH 5 pI without any activity, the latter with a pH 4, 1 pI with a high NAD-ase activity.     

Feeding and anhydrobiosis in bdelloid rotifers: a preparatory study for an experiment aboard the International Space Station

Abstract. Here we report the effect of food concentration on the recovery from anhydrobiosis of a bdelloid rotifer, Macrotrachela quadricornifera . Cohorts were either starved, or fed high or low concentrations of food, before being dried and their subsequent recovery rates determined. The rotifers starved for 3 d before anhydrobiosis recovered in significantly higher proportion, and those fed lower food concentration recovered better than those fed higher food concentration. In addition, starvation did not decrease the recovery of other bdelloid species ( Philodina roseola and Adineta sp. 1) which were either fed or starved before anhydrobiosis. These results suggest that a successful recovery from anhydrobiosis is not dependent on prior resource level supplied to the bdelloids. However, the lack of resources might not be the only factor in a successful recovery from anhydrobiosis. Observations using scanning electron microscopy of fed individuals of M. quadricornifera entering anhydrobiosis showed that some food remained in the digestive tract. Thus, we propose that the negative effect of rich food may be due to a purely mechanical effect and may be interfering with a proper folding of the rotifer body at the onset of anhydrobiosis. This contribution results from studies carried out in preparation for biological experiments scheduled on the International Space Station (ISS).     

In-vitro evaluation of morphine dependence. I. Response of the rat "fundus" to ACh]

The kinetic of cholinergic receptor systems was studied in an in vitro model for opiate tolerance and dependence. The fundus strip of rats chronically treated with morphine and sacrificed at different time intervals and in different conditions (with and without abstinence signs) was used. In evaluating the responses of fundus to ACh, the cholinergic receptor system showed the same response both in a condition of abstinence and in a condition of non-abstinence in vivo and in vitro. The response does vary however, according to the duration of the treatment: after an initial increase it comes back to its normal values, thus reproducing the tolerance pattern.