NOR polymorphism in the Iberian species Chondrostoma lusitanicum (Pisces: Cyprinidae)

Chromosomal polymorphism regarding number of NOR sites in the cyprinid fish Chondrostoma lusitanicum was examined using C-banding, silver-staining (Ag), and fluorescent staining with chromomycin A₃ (CMA₃). The analysis of heterochromatic regions allowed a more precise identification of the centromeric regions and the proposal of a revised haploid chromosome formula (7M: 15S: 3A). We describe variability in the number of NOR regions per genome, number of active NOR sites per cell, and relative size of individual NORs. Individuals expressed two or four NOR-bearing chromosomes. Polymorphism was detected in all the populations studied and sex-related differences were not found. The observed chromosomal NOR phenotypes suggest the occurrence of structural rearrangements during the evolutionary process of this diploid leuciscine cyprinid.     

Measurement of nutrient spiralling during a period of continuous surface flow in a Mediterranean temporary stream (Arroyo de La Montesina, Spain)

Uptake rate of calcium, potassium, nitrate-N and phosphorus were measured in a second order Mediterranean temporary stream, in February and March 1992. This study analyzed a period of continuous surface flow between two hydrologic disturbance events (flood and drought) of an annual hydrological cycle (1991–92).The lowest values of uptake length were recorded for nitrate-N in February 92 and calcium in March 92. Nitrate had the highest uptake rate in both release performances, and potassium showed the lowest uptake rate values. The increase of calcium and nitrate uptake rate between February 92 and March 92 suggested a higher ecosystem efficiency in nutrient retention with a higher temperature and light intensity and slower water velocity, discharge and water depth. These results obtained were similar to those reported in permanent streams, indicating that in periods of continuous surface flow (without extreme hydrologic disturbance), abiotic factors can influence nutrient retention in temporary streams.     

Flocculation of industrial and laboratory strains ofSaccharomyces cerevisiae

Summary A comparative study has been made of different laboratory and industrial wild-type strains ofSaccharomyces cerevisiae in relation to their flocculation behavior. All strains were inhibited by mannose and only one by maltose. In regard to the stability of these characters in the presence of proteases and high salt concentrations, a relevant degree of variation was found among the strains. This was to such an extent that it did not allow their inclusion in the Flol or NewFlo phenotypes. Genetic characterization of one wild-type strain revealed that the flocculation-governing gene was allelic toFLO1 found in genetic strains.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues.     

Histoplasma capsulatum peritonitis associated with continuous ambulatory peritoneal dialysis

This paper reports a case of infection byHistoplasma capsulatum apparently restricted to the peritoneum in a woman submitted to continuous ambulatory peritoneal dialysis. Diagnosis was established by culture of dialysis fluid and peritoneal nodule and by histopathologic examination.     

Chemical composition and larvicidal activity of essential oils of three Artemisia species

Aedes aegypti L. (Diptera: Culicidae) is a vector for serious diseases in tropical regions. This pest is mainly controlled by commercial larvicides but the application of such products has led to environmental problems. Essential oils (EO) have been consistently reported as molecules with insecticidal activity and can be used to produce more environmentally friendly larvicides in the control of A. aegypti. In this study, the larvicidal effect of essential oils (EO) from the leaves of three Artemisia species was evaluated against A. aegypti. The oils were obtained from steam distillation and their chemical composition was determined by gas chromatography–mass spectrometry. The EO of Artemisia camphorata was the most active in the screening bioassay and presented LC₅₀ and LC₉₅ of 64.95 and 74.18 μg ml⁻¹, respectively. In addition, we found that germacrene D-4-ol was the constituent responsible for the toxicity of this EO. Artemisia camphorata EO and its major constituent, germacrene D-4-ol, are promising for the development of natural larvicides against A. aegypti.     

Genetic differentiation and detection of cryptic species in the genus Lepismachilis (Insecta: Microcoryphia) from the Western Mediterranean region

Different species of the bristletail genus Lepismachilis were collected in 14 localities in Italy and Spain and an allozyme electrophoretic survey was carried out to estimate the degree of genetic variability and differentiation at intra- and interspecific levels. Four morphological species were initially identified (L osellai, L. y-signata, L. affinis, L. targionii), but the electrophoretic analysis demonstrated the presence of two additional species among the individuals of L. targionii (Lepismachilis spl and sp2). The validity of these species and their differentiation from L targionii were demonstrated by the fixation of alternative allelic patterns at several loci (7 in Lepismachilis spl and 8 in Lepismachilis sp2), coupled with fixed, previously undetected, morphological differences. In addition, Lepismachilis sp2 was sympatric with L. targionii in three collecting sites, where the fixation of alternative allelic patterns unequivocally demonstrated reproductive isolation. Genetic variability did not seem to be correlated with local ecological factors, and differences between species should rather be explained by different historical factors. Low levels of gene flow, estimated with two different indirect methods, were observed in L. targionii and L. y-signata, and were due to high levels of structuring among populations. Genetic differentiation among conspecific populations was not correlated to their geographical arrangement and the presence of loci fixed for different alleles among them suggested that stochastic factors (such as genetic drift) may have played a role in determining genetic differentiation of geographically isolated populations. Genetic divergence values indicated that the six species are well differentiated and allozyme profiles were diagnostic for all of them. On the other hand, allozyme data did not provide adequate information to resolve evolutionary relationships among the species, nor did they confirm the validity of the two subgenera (Lepismachilis and Berlesilis) in which the genus Lepismachilis is traditionally divided.     

A case of congenital syphilis during the colonial period in Mexico City

Congenital syphilis has been diagnosed very seldom in ancient populations. The case that we examined comes from San Jeronimo's Church (17th and 18th centuries AD; Mexico City). Coffin 43 contained an incomplete skeleton of an approximately 2-year-old infant. The pathological lesions of this skeleton include bilateral osteochondritis, diaphyseal osteomyelitis, and osteitis and/or periostitis on the long bones. The radiographic appearance depicts symmetrical osteomyelitic foci, particularly at the proximal extremity of both tibiae (Wimberger's sign). The skull exhibits hydroceph-aly and periosteal changes on the vault, and the unerupted upper incisors evince dental hypoplasia and other pathological alterations reminiscent of Hutchinson's incisors. All these features strongly suggest a case of early Congenital syphilis. © 1995 Wiley-Liss, Inc.     

Cutaneous zygomycosis caused byAbsidia corymbifera in a leukemic patient

A case of cutaneous zygomycosis caused byAbsidia coryabifera in a leukemic patient submitted to chemotherapy is reported. The lesion was located on the little finger of the right hand and probably resulted from a latent osteomyelitis. It progressed to form extensive necrotic area. No systemic infection was detected and the lesion did not appear to be associated with any trauma.