Mimosa splendida Barneby (Mimosoideae, Leguminosae) rediscovered in Central Brazil: preliminary studies for conservation of a rare species

The poorly known Mimosa splendida Barneby has been rediscovered in the Chapada dos Veadeiros, Brazil, 105 years after its single record in 1895. Data on its habitat description, demography, reproductive parameters, and geographic range are presented. Preliminary results suggest that the rarity of M. splendida in herbarium collections is associated with a narrow geographic range, and a specialized habitat preference on rocky slopes.

Juvenile dynamics of the endemic and rare Enterolobium glaziovii Benth. (Mimosaceae) around reproductive trees in the Atlantic forest, Brazil

Studies on the regeneration and seedling mortality of rare tree species are important, but scarce. The aim of this study was to investigate the annual variation in recruitment, growth and mortality of juveniles of Enterolobium glaziovii Benth., a rare tree species from the Brazilian Atlantic Rain Forest. All seedlings and juveniles around four reproductive trees were labeled and their fate was followed from 1996 to 1999. There were no annual differences in juveniles' recruitment below and beyond the parental crown, but juveniles' survival and growth were lower below than beyond of the parental tree crowns. Small individuals (< 15 cm tall) showed the greatest mortality and the lowest growth, followed by medium (from 15 to 50 cm tall) and large ones (> 50 cm tall). Large juveniles were more widely dispersed from the conspecific parental tree than were medium and small ones. This suggests that distance dependent mortality of juveniles mediated by the parental tree is an important cause of spacing shifts associated with the growth of small individuals of E. glaziovii into large ones. Widely dispersed juveniles may escape the high mortality associated with pathogens, herbivores or seed predators concentrated around adult conspecifics. The negative influence of the parental tree on its juveniles may explain the sparse distribution of its adults in the forest.

Occurrence of the rare genus Microcrocis P. Richter (Chroococcales, Cyanobacteria) in a coastal lagoon from southern Brazil

The paper records the first occurrence of the genus Microcrocis P. Richter (Chroococcales, Cyanobacteria), represented by M. pulchella (Buell) Geitler, in Brazil. The species was found in two zones, one with freshwater and the other with brackish water, of a coastal lagoon of Rio Grande do Sul State (31°15’-31°30’ S and 50°54’-51°09’ W). Comparison between M. pulchella and its most closely related species is presented. Up to now this species had occurrence records limited to freshwater systems in temperate regions. Its presence in a subtropical coastal lagoon from southernmost Brazil, either in fresh or in brackish water, broadened the knowledge of the distribution area of M. pulchella.

Rare adverse events associated with oral poliovirus vaccine in Brazil

Oral poliovirus vaccine (OPV) developed by A. Sabin has been effectively used to control poliomyelitis in Brazil, and the last case with the isolation of a wild poliovirus strain occurred in March 1989. Although the vaccine controlled the circulation of wild strains and poliomyelitis cases associated with these strains were not detected during the last eight years, rare cases classified as vaccine-associated paralytic poliomyelitis (VAPP) have been detected. Molecular characterization studies of poliovirus strains isolated from VAPP cases and from healthy contacts have confirmed that the isolates are derived from the Sabin vaccine strains and also detected genomic modifications known or suspected to increase neurovirulence such as mutations and recombination. The molecular characterization of polioviruses isolated during the last eight years from paralysis cases classified as Guillain-Barré (GBS) syndrome and transverse myelitits (TM), and from facial paralysis (FP) cases also confirmed the vaccine origin of the strains and demonstrated mutations known to increase neurovirulence. Analysis of the epidemiologic data of these GBS, TM and FP cases demonstrated that in most of them the last OPV dose was given months or years before the onset of the disease and the isolation of the polioviruses. The temporal association between the isolation of these strains and the GBS, TM and FP suggested that the Sabin vaccine-derived poliovirus strains could also rarely trigger the diseases.

The quality control of glycoprotein folding in the endoplasmic reticulum, a trip from trypanosomes to mammals

The present review deals with the stages of synthesis and processing of asparagine-linked oligosaccharides occurring in the lumen of the endoplasmic reticulum and their relationship to the acquisition by glycoproteins of their proper tertiary structures. Special emphasis is placed on reactions taking place in trypanosomatid protozoa since their study has allowed the detection of the transient glucosylation of glycoproteins catalyzed by UDP-Glc:glycoprotein glucosyltransferase and glucosidase II. The former enzyme has the unique property of covalently tagging improperly folded conformations by catalyzing the formation of protein-linked Glc1Man7GlcNAc2, Glc1Man8GlcNac2 and Glc1Man9GlcNAc2 from the unglucosylated proteins. Glucosyltransferase is a soluble protein of the endoplasmic reticulum that recognizes protein domains exposed in denatured but not in native conformations (probably hydrophobic amino acids) and the innermost N-acetylglucosamine unit that is hidden from macromolecular probes in most native glycoproteins. In vivo, the glucose units are removed by glucosidase II. The influence of oligosaccharides in glycoprotein folding is reviewed as well as the participation of endoplasmic reticulum chaperones (calnexin and calreticulin) that recognize monoglucosylated species in the same process. A model for the quality control of glycoprotein folding in the endoplasmic reticulum, i.e., the mechanism by which cells recognize the tertiary structure of glycoproteins and only allow transit to the Golgi apparatus of properly folded species, is discussed. The main elements of this control are calnexin and calreticulin as retaining components, the UDP-Glc:glycoprotein glucosyltransferase as a sensor of tertiary structures and glucosidase II as the releasing agent.

An EDTA-β-cyclodextrin adsorbent for the adsorption of rare earth elements and its application in preconcentration of ultratrace rare earth elements from seawater

The objectives of this work were synthesizing an EDTA-β-CD adsorbent and investigating its adsorption potential and applications in preconcentration of REEs from aqueous phase. The adsorption capacity of EDTA-β-CD was investigated. The adsorption studies were performed by batch techniques both in one- and multi-component systems. The effects of pH, contact time and initial concentration were evaluated. The analytical detection methods and characterization methods were presented. EDTA-β-CD adsorbent was synthesized successfully with high EDTA coverage. The maximum REEs uptake was 0.310 mmol g-1 for La(III), 0.337 mmol g-1 for Ce(III) and 0.353 mmol g-1 for Eu(III), respectively. The kinetics of REEs onto EDTA-β-CD fitted well to pseudo-second-order model and the adsorption rate was affected by intra-particle diffusion. The experimental data of one component studies fitted to Langmuir isotherm model indicating the homogeneous surface of the adsorbent. The extended Sips model was applicable for the isotherm studies in three-component system. The electrostatic interaction, chelation and complexation were all involved in the adsorption mechanism. The preconcentration of RE ions and regeneration of EDTA-β-CD were successful. Overall, EDTA-β-CD is an effective adsorbent in adsorption and preconcentration of REEs.

Emission, kinetic and magnetic phenomena in rare-earth and transition metal doped ZnSe single crystals

In this work emission, optical, electrical and magnetic properties of the d- and f- elements doped zinc selenide crystals were investigated within a wide temperature range. Doping was performed in various technological processes: during the growth by chemical vapor transport method; by thermal diffusion from the Bi or Zn melt. Concentration of the doping impurity in the crystals was controlled by amount of the dopant in the source material or by its concentration in the doping media. Special interest in the work was paid to the influence of the different concentrations of Cr and Yb impurities on ZnSe crystals’ properties, correlations between observed effects and similarities with the Ni, Mn and Gd dopants are analysed. Possibility of formation of the excitons bound to the doping d-ions was shown. In contrast to this, it was observed that f-elements do not bound excitons, but prevent formation of excitons bound to some uncontrolled impurities. A mechanism of Cr doping impurity interaction with background impurities and zinc selenide structural defects was proposed based on experimental data. An assumption about resonant energy transfer between double charged chromium ions and complexes based on crystals’ vacancy defects was made. A correlation between emission and magnetic properties of the d- ions doped samples was established. Based on this correlation a mechanism explaining the concentration quench of the emission was proposed. It was found that f-ions bind electrically active shallow and deep donor and acceptor states of background impurity to electrically neutral complexes. This may be observed as “purification” of ZnSe crystals by doping with the rare-earth elements, resulting i tendency of the properties of f-ion doped crystals to the properties of intrinsic crystals, but with smaller concentration of uncontrolled native and impurity defects. A possible interpretation of this effect was proposed. It was shown that selenium substituting impurities decrease efficiency of the Yb doping. Based on this experimental results an attempt to determine ytterbium ion surroundings in the crystal lattice was made. It was shown that co-doping of zinc selenide crystals with the d- and f- ions leads to the combination of the impurities influence on the material’s properties. On the basis of obtained data an interaction mechanism of the d- and f-elements co-dopants was proposed. Guided by the model of the ytterbium ion incorporation in the selenide sublattice of the ZnSe crystals, an assumption about stabilization of single charged chromium ions in the zinc sublattice crystal nodes, by means of formation of the local charge compensating clusters, was made.

Defensive responses to threat scenarios in Brazilians reproduce the pattern of Hawaiian Americans and non-human mammals

A former study with scenarios conducted in Hawaii has suggested that humans share with non-human mammals the same basic defensive strategies - risk assessment, freezing, defensive threat, defensive attack, and flight. The selection of the most adaptive strategy is strongly influenced by features of the threat stimulus - magnitude, escapability, distance, ambiguity, and availability of a hiding place. Aiming at verifying if these strategies would be consistent in a different culture, 12 defensive scenarios were translated into Portuguese and adapted to the Brazilian culture. The sample consisted of male and female undergraduate students divided into two groups: 76 students, who evaluated the five dimensions of each scenario and 248 medical students, who chose the most likely response for each scenario. In agreement with the findings from studies of non-human mammal species, the scenarios were able to elicit different defensive behavioral responses, depending on features of the threat. "Flight" was chosen as the most likely response in scenarios evaluated as an unambiguous and intense threat, but with an available route of escape, whereas "attack" was chosen in an unambiguous, intense and close dangerous situation without an escape route. Less urgent behaviors, such as "check out", were chosen in scenarios evaluated as less intense, more distant and more ambiguous. Moreover, the results from the Brazilian sample were similar to the results obtained in the original study with Hawaiian students. These data suggest that a basic repertoire of defensive strategies is conserved along the mammalian evolution because they share similar functional benefits in maintaining fitness.

A simple model for circadian timing by mammals

Circadian timing is structured in such a way as to receive information from the external and internal environments, and its function is the timing organization of the physiological and behavioral processes in a circadian pattern. In mammals, the circadian timing system consists of a group of structures, which includes the suprachiasmatic nucleus (SCN), the intergeniculate leaflet and the pineal gland. Neuron groups working as a biological pacemaker are found in the SCN, forming a biological master clock. We present here a simple model for the circadian timing system of mammals, which is able to reproduce two fundamental characteristics of biological rhythms: the endogenous generation of pulses and synchronization with the light-dark cycle. In this model, the biological pacemaker of the SCN was modeled as a set of 1000 homogeneously distributed coupled oscillators with long-range coupling forming a spherical lattice. The characteristics of the oscillator set were defined taking into account the Kuramoto's oscillator dynamics, but we used a new method for estimating the equilibrium order parameter. Simultaneous activities of the excitatory and inhibitory synapses on the elements of the circadian timing circuit at each instant were modeled by specific equations for synaptic events. All simulation programs were written in Fortran 77, compiled and run on PC DOS computers. Our model exhibited responses in agreement with physiological patterns. The values of output frequency of the oscillator system (maximal value of 3.9 Hz) were of the order of magnitude of the firing frequencies recorded in suprachiasmatic neurons of rodents in vivo and in vitro (from 1.8 to 5.4 Hz).

Triorganotin as a compound with potential reproductive toxicity in mammals

Organotin compounds are typical environmental contaminants and suspected endocrine-disrupting substances, which cause irreversible sexual abnormality in female mollusks, called "imposex". However, little is known about the capability of triorganotin compounds, such as tributyltin and triphenyltin, to cause disorders in the sexual development and reproductive functions of mammals, including humans and rodents. Moreover, these compounds can act as potential competitive inhibitors of aromatase enzyme and other steroidogenic enzymes, affecting the reproductive capacity of male and female mammals. In this review, we discuss the cellular, biochemical, and molecular mechanisms by which triorganotin compounds induce adverse effects in the mammalian reproductive function.

Lipoprotein glomerulopathy: a case report of a rare disease in a brazilian child

Lipoprotein glomerulopathy (LPG) is a rare autosomal recessive glomerulopathy associated with the deposition of lipoprotein thrombi in the capillary lumina due to apoE gene mutations. Abnormal plasma lipoprotein profile and marked increase in serum apoliprotein E (apoE) are characteristic clinical data. The compromised patients can present nephrotic syndrome, hematuria, and progressive renal failure. Herein, the authors present the first described case of LPG in a Brazilian male patient, 11 years, who presented with a steroid-resistant nephrotic syndrome. Renal function was normal. Kidney biopsy showed markedly enlarged glomerulus, with dilated capillary loops and weak eosinophilic lipoprotein thrombi in the capillary lumina. Interstitium, tubules, arteries, and veins showed normal histologic aspect. Genotypic study for the apoE gene showed the presence of the alleles E3 and E4. The diagnosis of LPG was then performed. The patient received lipid-lowering treatment. After 2 years of follow-up, renal function is gradually decreasing, with persisting heavy proteinuria, despite a marked decrease in serum cholesterol and triglycerides levels.

Cat Scratch Disease in kidney transplant receptors: is it a rare or underdiagnosed pathology?

Cat Scratch Disease (CSD) is an infectious disorder which appears after cat scratching particularly in children and adolescents. Bartonella henselae is the etiologic agent more frequently involved. There are only a few recent reports demonstrating the disease after transplantation, although the illness is not infrequent in immunologically competent people. Indeed CSD in transplant receptors has only been recently emphasized in the literature and it was concluded that fever and lymphadenopathy in patients who had been exposed to cats should prompt clinicians to maintain a suspicion for the infection. In this report CSD infecting a renal transplanted adolescent complaining of headache, blurred vision and fever, presenting a cat scratching lesion in the right arm, with a bilateral painful cervical lymphadenopathy was related. He also presented indirect immunofluorescency identifying that the two subtype's titles of Bartonella-henselae and quintana- were elevated. Treatment with doxicicline e rifampicin was introduced and the patient became asymptomatic in about 3 weeks.

Carriage of herpes simplex virus and human papillomavirus in oral mucosa is rare in young women: a long-term prospective follow-up

Herpes simplex -virus 1 (HSV-1) ja ihmisen papilloomavirus (HPV) infektoivat suun epiteelisoluja. Useimmissa tapauksissa näiden virusten infektio on kliinisesti oireeton. Suun limakalvojen oireeton HPV-infektio on aikuisilla yleinen, ja valtaosa näistä infektioista ovat ohimeneviä ja vain pieni osa johtaa krooniseen HPV-infektioon. Krooninen HPV-infektio lisää riskiä epiteelisolujen transformoitumiseen kohti syöpäsolua. HPV infektio ei ole yksinään riittävä aiheuttamaan syöpäsolun, vaan siihen tarvitaan myös muita riskitekijöitä.. Muut infektiot, kuten esimerkiksi HSV-1-infektio saattaa olla yksi näistä riskitekijöistä. Tämän syventävän opinnäytetyön tutkimuksen tavoitteena oli selvittää HSV-1-infektion esiintymistä naisten suun limakalvonäytteissä kuuden vuoden seurannassa. Toinen tavoitteemme oli selvittää HSV-1 ja HPV -yhteisinfektion esiintymistä suun epiteelisoluissa, erityisesti naisilla joilla havaittiin suun krooninen HPV-infektio. Tämä tutkimus on osa kuusivuotista seurantatutkimusta (Finnish Family HPV -tutkimus), joka suunniteltiin selvittämään HPV-infektioiden dynamiikkaa ja riskitekijöitä 329 suomalaisperheessä. Suun limakalvoilta otettiin harjausnäyte ennen synnytystä ja kuusi kertaa synnytyksen jälkeen kuuden vuoden aikana. Näytteistä eristettyä DNA:ta oli saatavilla riittävästi HSV-1-analyysiä varten yhteensä 304 naiselta (keski-ikä 25.6 vuotta). Kaikkiaan tutkittavia näytteitä oli 1,873, joista HSV-1:n esiintyminen tutkittiin käyttäen kvantitatiivista PCR:ää. Lisäksi epävarmat PCR-tulokset varmistettiin PCR-tuotteen Southern Blot hybridisaatiolla. HSV-1 tuloksia verrattiin aikaisemmin saatuihin HPV-tuloksiin. Suun limakalvonäytteistä 2.2% oli HSV-1-positiivisia ja 19.6% oli HPV-positiivisia. Yhteensä 11.8%:lla äideistä suunäyte oli HSV-1-DNA -positiivinen ainakin kerran seurannan aikana. HSV-1 ja HPV -yhteisinfektio löydettiin vain neljältä äidiltä. Suurin osa äideistä, jotka olivat HSV-1-positiivisia ennen syntymää, pysyivät HSV-1-positiivisina myös synnytyksen jälkeen. Kolmella naisella todettiin persistentti HPV-16 infektio ja kahdella heistä oli samanaikainen HSV-1 infektio. Tuloksemme osoittaa, että HSV-1:n ja HPV:n esiintyminen yhtä aikaa nuorten naisten suun limakalvolla on harvinaista. On suositeltavaa, että yhteisinfektion omaavia äitejä seurataan myös tulevaisuudessa, sillä HSV-1-infektio saattaa olla yksi riskitekijä suun limakalvon malignissa muutoksessa kroonisen HPV-infektion yhteydessä.