Cryptic speciation in the field vole: a multilocus approach confirms three highly divergent lineages in Eurasia

Species are generally described from morphological features, but there is growing recognition of sister forms that show substantial genetic differentiation without obvious morphological variation and may therefore be considered ‘cryptic species’. Here, we investigate the field vole (Microtus agrestis), a Eurasian mammal with little apparent morphological differentiation but which, on the basis of previous sex‐linked nuclear and mitochondrial DNA (mtDNA) analyses, is subdivided into a Northern and a Southern lineage, sufficiently divergent that they may represent two cryptic species. These earlier studies also provided limited evidence for two major mtDNA lineages within Iberia. In our present study, we extend these findings through a multilocus approach. We sampled 163 individuals from 46 localities, mainly in Iberia, and sequenced seven loci, maternally, paternally and biparentally inherited. Our results show that the mtDNA lineage identified in Portugal is indeed a distinct third lineage on the basis of other markers as well. In fact, multilocus coalescent‐based methods clearly support three separate evolutionary units that may represent cryptic species: Northern, Southern and Portuguese. Divergence among these units was inferred to have occurred during the last glacial period; the Portuguese lineage split occurred first (estimated at c. 70 000 bp ), and the Northern and Southern lineages separated at around the last glacial maximum (estimated at c. 18 500 bp ). Such recent formation of evolutionary units that might be considered species has repercussions in terms of understanding evolutionary processes and the diversity of small mammals in a European context.     

Use of acyclovir in the prevention of herpes infections after allogenic bone marrow grafts

In a double-bind controlled study, oral Acyclovir has been compared to a placebo in a series of 39 consecutive patients undergoing bone marrow transplantation. A dose of 200 mg was given every 6 h from day 8 to day 35 after transplantation. Pharmacokinetic studies have shown the good absorption of the drug despite intestinal damage related to chemoradiotherapy or gut graft-versus-host disease (GVHD), there was no sign of toxicity. The protection against herpes simplex virus (HSV) infection was complete in the treated group when compared to the control group even in patients with high anti-HSV antibody titres. The same protection was observed against cytomegalovirus (CMV) infection. The incidence of HSV and CMV was the same in both groups after treatment ended. This study confirms the efficacy of Acyclovir against HSV infection and possibly against CMV infection when it is given prophylactically after bone marrow transplantation.     

Nisin stimulates oxygen consumption by Staphylococcus aureus and Escherichia coli.

Nisin stimulated oxygen consumption by nongrowing, glucose-metabolizing Staphylococcus aureus and Escherichia coli cells, indicating a protonophore mode of action. A similar stimulation in E. coli cells osmotically stressed to disrupt the outer cell membrane confirmed the cytoplasmic membrane as the site of nisin action and showed that nisin uptake was not prevented by the outer membrane.     

The cytotaxonomy ofEmilia spp. (Asteraceae: Senecioneae) occurring in Brazil

Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes.     

Gating properties of channels formed by colicin Ia in planar lipid bilayer membranes

Summary Colicin Ia forms voltage-dependent channels when incorporated into planar lipid bilayers. A membrane containing many Colicin Ia channels shows a conductance which is turned on when high positive voltages (>+10 mV) are applied to thecis side (side to which the protein is added). The ionic current flowing through the membrane in response to a voltage step shows at first an exponential and then a linear rise with time. The relationship between the steady-state conductance, achieved immediately after the exponential portion, and voltage is S-shaped and is adequately fit by a Boltzmann distribution. The time constant () of the exponential is also dependent on voltage, and the relation between these two parameters is asymmetric aroundV _o (voltage at which half of the channels are open). In both cases the steepness of the voltage dependence, a consequence of the number of effective gating particles (n) present in the channel, is greatly influenced by the pH of the bathing solutions. Thus, increasing the pH leads to a reduction inn, while acidic pH's have the opposite effects. This result is obtained either by changing the pH on both sides of the membrane or on only one side, be itcis orrans. On the other hand, changing pH on only one side by addition of an impermeant buffer fails to induce any change inn. At the single-channel level, pH had an effect both on the unitary conductance, doubling it in going from pH 4.5 to 8.2, as well as on the fraction of time the channels stay open,F _(v). For a given voltage,F _(v) is clearly diminished by increasing the pH. This titration of the voltage sensitivity leads to the conclusion that gating in the Colicin Ia molecule is accomplished by charged amino-acid residues present in the protein molecule. Our results also support the notion that these charged groups are inside the aqueous portion of the channel.     

Gelatin as a vehicle for food and vitamin administration to marmosets

For a period of three years, gelatin was used as a vehicle for administration of food, vitamin complex and drugs to laboratory maintained Callithrix penicillata and Callithrix jacchus marmosets and a breeding colony of C. penicillata. In both circumstances, results were satisfactory. The animals survived for long periods of time, with adult, young and juvenile primates in the breeding colony showing good physical condition.     

Conditioned media from cultured cystic fibrosis fibroblasts inhibits Na/K ATPase activity

Conditioned culture media taken from fibroblast cell lines derived from skin biopsies of control or of patients with Cystic Fibrosis (CF) were incubated with membranes of rat submandibular glands. The Na/K - ATPase activity of these membranes was inhibited when treated with CF-media, including both ouabain sensitive and insensitive activities. However, the membrane associated Mg-ATPase, Ca-ATPase, and both basal and hormone-stimulated adenylate cyclase activities were relatively unaffected. Thus, a factor or factors produced by CF-fibroblasts was shown to be active in a cell-free system derived from an exocrine gland.     

Chemotherapy of Aspergillus fumigatus keratitis: An experimental study

An experimental Keratitis study of Aspergillus fumigatus was performed in 130 rabbits divided into 12 groups of ten animals each. Three antifungal drugs (myconazole, amphotericin B and pimaricin) were tested using two procedures (topical drops and subconjunctival injections) and two different concentrations (500 and 10 000 times the MIC). In each case, the drugs were applied every 3 h starting 14 h after inoculation. Miconazole was useful at 10 mg/ ml concentration by topical drops and subconjunctival injections, but was less useful at 5 mg/ ml. Amphotericin B was useful at 5 mg/ ml concentration by topical drops and less useful at 2 mg/ ml.No differences were found between the two concentrations by subconjunctival administration. Pimaricin was useful by topical drops at 50 mg/ ml concentration and less useful at 10 mg/ ml as well as by subconjunctival injections.     

A pre-formed Pyrogenic Factor Released by Lipopolysaccharide Stimulated Macrophages

The aim of this study was to investigate the pyrogenic activity of factor(s) released by rat peritoneal macrophages following a brief stimulation with LPS. The effect of this factor on the number of circulating leukocytes and serum Fe, Cu and Zn levels, was also evaluated. The possibility that the content of interleukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF) in the supernatant could explain the observations was investigated. Supernatant produced over a period of 1 h by peritoneal macrophages, following a 30 min incubation with LPS at 37 degrees C, was ultrafiltered through a 10 000 MW cut-off Amicon membrane, sterilized, and concentrated 2.5, 5, 10 and 20 times. The intravenous (i.v.) injection of this supernatant induced a concentration-dependent fever in rats with a maximal response at 2 h. The pyrogenic activity was produced by macrophages elicited with thioglycollate and by resident cells. The supernatants also induced neutrophilia and reduction in Fe and Zn 6 h after the injection. Absence of activity in boiled supernatants, or supernatants from macrophages incubated at 4 degrees C with LPS, indicates that LPS was not responsible for the activity. In vitro treatment with indomethacin (Indo), dexamethasone (Dex), or cycloheximide (Chx) did not modify the release of pyrogenic activity into the supernatant or its effects on the reduction in serum metal levels. Although Chx abolished the production of mediator(s) inducing neutrophilia, and Dex reduced the induction of IL-1beta, TNF and IL-6, injection of the highest concentration of these cytokines detected in the supernatants did not induce fever. In vivo treatment with Dex, but not Indo, abolished the fever induced by the supernatant. These results suggest that macrophages contain pre-formed pyrogenic mediator(s), not related to IL-1beta, IL-6 or TNF, that acts indirectly and independently of prostaglandtn. It also seems likely that the pyrogenic activity is related to the factor responsible for the reduction of serum Fe and Zn levels, but not the neutrophilia.