Habitat monitoring and genotoxicity in Ucides cordatus (Crustacea: Ucididae), as tools to manage a mangrove reserve in southeastern Brazil

In Brazil, the state of São Paulo contains both preserved areas (Juréia-Itatins Ecological Station) and extremely impacted ones (Cubatão Municipality). This study evaluated the concentrations of five metals (Cu, Cd, Cr, Pb, and Hg) in two mangroves with different levels of anthropogenic impact and the apparent genotoxicity to Ucides cordatus. Water and sediment samples were obtained, and metal concentrations were determined with an atomic absorption spectrophotometer. The genotoxic impact was quantified based on the number of micronucleated cells per 1,000 analyzed (MN‰), using hemolymph slides stained with Giemsa. Metal concentrations in water were below the detection limit, except for lead, although no significant difference was observed between the areas (P > 0.05). Sediment from Cubatão had higher concentrations of Cd, Pb, Cr, and Cu than sediment from Juréia-Itatins (P < 0.05), but no significant differences in metal concentrations were detected among depth strata of the sediment (P > 0.05). Crabs from Cubatão had a 2.6 times higher mean frequency of micronucleated cells (5.2 ± 1.8 MN‰) than those from Juréia-Itatins (2.0 ± 1.0 MN‰; P < 0.0001). The more-polluted conditions found in the mangrove sediments of Cubatão were reflected in the micronucleus assay, demonstrating their genotoxic effect; however, genetic damage should be attributed to a synergistic effect with other kinds of pollutants previously recorded in different environments of Cubatão. U. cordatus proved to be an excellent bioindicator of mangrove pollution. This study established, for the first time, the normal frequency of MN‰ in a population of this species within an ecological station. © 2013 Springer Science+Business Media Dordrecht.

Aspects of Mechanical Behavior and Modeling of a Tropical Unsaturated Soil

The research studies the applicability of two elastoplastic models for the collapse prediction of the lateritic soil profile from Southeastern Brazil. These tropical soils have peculiar geotechnical behavior, due to their mineralogical composition and porous structure coming from intense process of formation. Two elastoplastic models were analyzed: the Barcelona Basic Model (BBM) and another one based on BBM, however developed for tropical soils. Oedometric tests with suction control were performed at three distinct depths of the soil profile. The BBM was not suitable for the upper layer of the soil profile, because BBM considers the compressible behavior of the soil in function of the reduction of the elastoplastic compressibility index with the increase of the matric suction. The model developed for tropical soils showed better suited to the compressible behavior of the soil profile, resulting in good prediction of the collapse potential, mainly by accepting increasing values of the elastoplastic compressibility index of the soil profile with the matric suction rise. © 2013 Springer Science+Business Media Dordrecht.

Topological K-classification of finitely determined map germs

We consider smooth finitely C 0-K-determined map germs f: (ℝn, 0) → (ℝp, 0) and we look at the classification under C 0-K-equivalence. The main tool is the homotopy type of the link, which is obtained by intersecting the image of f with a small enough sphere centered at the origin. When f -1(0) = {0}, the link is a smooth map between spheres and f is C 0-K-equivalent to the cone of its link. When f -1(0) ≠ {0}, we consider a link diagram, which contains some extra information, but again f is C 0-K-equivalent to the generalized cone. As a consequence, we deduce some known results due to Nishimura (for n = p) or the first named author (for n < p). We also prove some new results of the same nature. © 2012 Springer Science+Business Media Dordrecht.

Influence of potassium and sodium nutrition on leaf area components in Eucalyptus grandis trees

Background and Aims: Recent studies showed a positive tree response to Na addition in K-depleted tropical soils. Our study aimed to gain insight into the effects of K and Na fertilizations on leaf area components for a widely planted tree species. Methods: Leaf expansion rates, as well as nutrient, polyol and soluble sugar concentrations, were measured from emergence to abscission of tagged leaves in 1-year-old Eucalyptus grandis plantations. Leaf cell size and water status parameters were compared 1 and 2 months after leaf emergence in plots with KCl application (+K), NaCl application (+Na) and control plots (C). Results: K and Na applications enhanced tree leaf area by increasing both leaf longevity and the mean area of individual leaves. Higher cell turgor in treatments +K and +Na than in the C treatment resulting from higher concentrations of osmotica contributed to increasing both palisade cell diameters and the size of fully expanded leaves. Conclusions: Intermediate total tree leaf area in treatment +Na compared to treatments C and +K might result from the capacity of Na to substitute K in osmoregulatory functions, whereas it seemed unable to accomplish other important K functions that contribute to delaying leaf senescence. © 2013 Springer Science+Business Media Dordrecht.

Leaf senescence in tomato mutants as affected by irradiance and phytohormones

We explored the interaction between radiation of different wavelength and jasmonic acid (JA) or brassinosteroids (BR) on leaf senescence-induced oxidative stress. Three approaches were used: 1) jasmonic acid insensitive1-1 (jai1-1) and brassinosteroid-deficient [dumpy (dpy)] mutants were treated with red (R) or far-red (FR) radiation; 2) phytochromedeficient aurea (au) and high pigment-1 (hp-1) (radiation exaggerated response) mutants were treated with methyl jasmonate (MeJA) or epibrassinolide (epiBL); and 3) double mutants au jai1-1 and au dpy were produced. Leaf chlorophyll content, lipid peroxidation, and antioxidant enzyme activities were determined. After senescence induction in detached leaves, we verified that the patterns of chlorophyll degradation of hormonal and photomorphogenic mutants were not significantly different in comparison with original cv. Micro-Tom (MT). Moreover, there was no significant change in lipid peroxidation measured as malondialdehyde (MDA) production, as well as catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities in the hormonal mutants. Exogenous BR increased CAT and APX activities in MT, au, and hp-1. As concerns the double mutants, severe reduction in H2O2 production which was not accompanied by changes in MDA content, and CAT and APX activities was observed during senescence in au dpy. The results suggest that JA and BR do not participate in light signaling pathway during leaf senescence-induced oxidative stress. © 2013 Springer Science+Business Media Dordrecht.

Thermal degradation of both latex and latex cast films forming membranes: combined TG/FTIR investigation

Latex collected from natural rubber trees forming membranes can be used as biomaterials in several fields being the temperature a key parameter. Thermogravimetry (TG) coupled to Fourier transform infrared spectroscopy (FTIR) is a useful technique to investigate the thermal degradation of both latex and cast films (membranes), wich were obtained from Hevea brasiliensis (RRIM 600 clone) and used without stabilization. The membranes were prepared by casting the latex onto a glass substrate at 65 degrees C for 6 h. The thermal degradation was followed by FTIR spectra acquisition along the process, allowing the identification of the gaseous components evolved upon the thermal treatment. According to TG measurements, the main processes of thermal degradation of the latex and membranes occur at three temperature intervals for both.

Solid-state compounds of 2-methoxybenzylidenepyruvate with some bivalent metal ions - Synthesis, characterization and thermal behavior studies

Solid-state M-2-MeO-BP compounds, where M represents bivalent Mn, Fe, Co, Ni, Cu, Zn and 2-MeO-BP is 2-methoxybenzylidenepyruvate have been synthesized. Simultaneous thermogravinietry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal stability and thermal decomposition of these compounds. The results led to information about the composition, dehydration, crystallinity and thermal decomposition of the isolated compounds.

Biological evolution of replicator systems: towards a quantitative approach

The aim of this work is to study the features of a simple replicator chemical model of the relation between kinetic stability and entropy production under the action of external perturbations. We quantitatively explore the different paths leading to evolution in a toy model where two independent replicators compete for the same substrate. To do that, the same scenario described originally by Pross (J Phys Org Chem 17:312–316, 2004) is revised and new criteria to define the kinetic stability are proposed. Our results suggest that fast replicator populations are continually favored by the effects of strong stochastic environmental fluctuations capable to determine the global population, the former assumed to be the only acting evolution force. We demonstrate that the process is continually driven by strong perturbations only, and that population crashes may be useful proxies for these catastrophic environmental fluctuations. As expected, such behavior is particularly enhanced under very large scale perturbations, suggesting a likely dynamical footprint in the recovery patterns of new species after mass extinction events in the Earth’s geological past. Furthermore, the hypothesis that natural selection always favors the faster processes may give theoretical support to different studies that claim the applicability of maximum principles like the Maximum Metabolic Flux (MMF) or Maximum Entropy Productions Principle (MEPP), seen as the main goal of biological evolution.

Angiotensin II type 2 receptor (AT2R) is associated with increased tolerance of the hyperthyroid heart to ischemia-reperfusion

Background Thyroid hormone induces cardiac hypertrophy and preconditions the myocardium against Ischemia/Reperfusion (I/R) injury. Type 2 Angiotensin II receptors (AT2R) are shown to be upregulated in cardiac hypertrophy observed in hyperthyroidism and this receptor has been reported to mediate cardioprotection against ischemic injury. Methods The aim of the present study was to evaluate the role of AT2R in the recovery of myocardium after I/R in isolated hearts from T3 treated rats. MaleWistar rats were treated with triiodothyronine (T3; 7 μg/100 gBW/day, i.p.) in the presence or not of a specific AT2R blocker (PD123,319; 10 mg/Kg) for 14 days, while normal rats served as control. After treatment, isolated hearts were perfused in Langendorff mode; after 30 min of stabilization, hearts were subjected to 20 min of zero-flow global ischemia followed by 25 min, 35 min and 45 min of reperfusion. Results T3 treatment induced cardiac hypertrophy, which was not changed by PD treatment. Post-ischemic recovery of cardiac function was increased in T3-treated hearts after 35 min and 45 min of reperfusion as compared to control and the ischemic contracture was accelerated and intensified. AT2R blockade was able to return the evaluated functional parameters of cardiac performance (LVDP, +dP/dtmáx and −dP/dtmin) to the control condition. Furthermore, AT2R blockade prevented the increase in AMPK expression levels induced by T3, suggesting its possible involvement in this process. Conclusion AT2R plays a significant role in T3-induced cardioprotection.

Relative CO2/NH3 permeabilities of human RhAG, RhBG and RhCG

Mammalian glycosylated rhesus (Rh) proteins include the erythroid RhAG and the nonerythroid RhBG and RhCG. RhBG and RhCG are expressed in multiple tissues, including hepatocytes and the collecting duct (CD) of the kidney. Here, we expressed human RhAG, RhBG and RhCG in Xenopus oocytes (vs. H2O-injected control oocytes) and used microelectrodes to monitor the maximum transient change in surface pH (ΔpHS) caused by exposing the same oocyte to 5 % CO2/33 mM HCO3 − (an increase) or 0.5 mM NH3/NH4 + (a decrease). Subtracting the respective values for day-matched, H2O-injected control oocytes yielded channel-specific values (*). (ΔpH∗S)CO2 and (−ΔpH∗S)NH3 were each significantly >0 for all channels, indicating that RhBG and RhCG—like RhAG—can carry CO2 and NH3. We also investigated the role of a conserved aspartate residue, which was reported to inhibit NH3 transport. However, surface biotinylation experiments indicate the mutants RhBGD178N and RhCGD177N have at most a very low abundance in the oocyte plasma membrane. We demonstrate for the first time that RhBG and RhCG—like RhAG—have significant CO2 permeability, and we confirm that RhAG, RhBG and RhCG all have significant NH3 permeability. However, as evidenced by (ΔpH∗S)CO2/(−ΔpH∗S)NH3 values, we could not distinguish among the CO2/NH3 permeability ratios for RhAG, RhBG and RhCG. Finally, we propose a mechanism whereby RhBG and RhCG contribute to acid secretion in the CD by enhancing the transport of not only NH3 but also CO2 across the membranes of CD cells.

Rickettsial infection in Amblyomma cajennense ticks and capybaras (Hydrochoerus hydrochaeris) in a Brazilian spotted fever-endemic area

Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, is the deadliest spotted fever of the world. In most of the BSF-endemic areas, capybaras (Hydrochoerus hydrochaeris) are the principal host for the tick Amblyomma cajennense, which is the main vector of BSF. In 2012, a BSF case was confirmed in a child that was bitten by ticks in a residential park area inhabited by A. cajennense-infested capybaras in Itú municipality, southeastern Brazil. Host questing A. cajennense adult ticks were collected in the residential park and brought alive to the laboratory, where they were macerated and intraperitoneally inoculated into guinea pigs. A tick-inoculated guinea pig that presented high fever was euthanized and its internal organs were macerated and inoculated into additional guinea pigs (guinea pig passage). Tissue samples from guinea pig passages were also used to inoculate Vero cells through the shell vial technique. Infected cells were used for molecular characterization of the rickettsial isolate through PCR and DNA sequencing of fragments of three rickettsial genes (gltA, ompA, and ompB). Blood serum samples were collected from 172 capybaras that inhabited the residential park. Sera were tested through the immunofluorescence assay using R. rickettsii antigen. A tick-inoculated guinea pig presented high fever accompanied by scrotal reactions (edema and marked redness). These signs were reproduced by consecutive guinea pig passages. Rickettsia was successfully isolated in Vero cells that were inoculated with brain homogenate derived from a 3rd passage-febrile guinea pig. Molecular characterization of this rickettsial isolate (designated as strain ITU) yielded DNA sequences that were all 100% identical to corresponding sequences of R. rickettsii in Genbank. A total of 83 (48.3%) out of 172 capybaras were seroreactive to R. rickettsii, with endpoint titers ranging from 64 to 8192. A viable isolate of R. rickettsii was obtained from the tick A. cajennense, comprising the first viable R. rickettsi isolate from this tick species during the last 60 years. Nearly half of the capybara population of the residential park was seroreactive to R. rickettsii, corroborating the findings that the local A. cajennense population was infected by R. rickettsii.

The effect of bone allografts combined with bone marrow stromal cells on the healing of segmental bone defects in a sheep model

Background: The repair of large bone defects is a major orthopedic challenge because autologous bone grafts are not available in large amounts and because harvesting is often associated with donor-site morbidity. Considering that bone marrow stromal cells (BMSC) are responsible for the maintenance of bone turnover throughout life, we investigated bone repair at a site of a critically sized segmental defect in sheep tibia treated with BMSCs loaded onto allografts. The defect was created in the mid-portion of the tibial diaphysis of eight adult sheep, and the sheep were treated with ex-vivo expanded autologous BMSCs isolated from marrow aspirates and loaded onto cortical allografts (n = 4). The treated sheep were compared with control sheep that had been treated with cell-free allografts (n = 4) obtained from donors of the same breed as the receptor sheep. Results: The healing response was monitored by radiographs monthly and by computed tomography and histology at six, ten, fourteen, and eighteen weeks after surgery. For the cell-loaded allografts, union was established more rapidly at the interface between the host bone and the allograft, and the healing process was more conspicuous. Remodeling of the allograft was complete at 18 weeks in the cell-treated animals. Histologically, the marrow cavity was reestablished, with intertrabecular spaces being filled with adipose marrow and with evidence of focal hematopoiesis. Conclusions: Allografts cellularized with AOCs (allografts of osteoprogenitor cells) can generate great clinical outcomes to noncellularized allografts to consolidate, reshape, structurally and morphologically reconstruct bone and bone marrow in a relatively short period of time. These features make this strategy very attractive for clinical use in orthopedic bioengineering

Isolation of Sporothrix schenckii from the claws of domestic cats (indoor and outdoor) and in captivity in São Paulo (Brazil)

Sporotrichosis is a subcutaneous mycosis and is also a zoonosis (sapro- and anthropozoonosis). The objective of the present study was to determine the occurrence of sporotrichosis in domestic cats and in wild or exotic felines in captivity through the isolation of Sporothrix spp. from claw impressions in a culture medium. The samples included 132 felines, of which 120 (91.0 %) were domestic cats, 11 (8.3 %) were wild felines, and one (0.7 %) was an exotic felid. Twenty-one (17.5 %) were outdoor cats. Of the total, 89 (67.4 %) had contact with other animals of the same species. It was possible to isolate Sporothrix schenckii from the claws of one (0.7 %) of the felids probed; this animal exhibited generalised sporotrichosis and had infected a female veterinarian. The potential pathogenic agents Microsporum canis and Malassezia pachydermatis were isolated in 12.1 and 5.3 % of the animals, respectively. The following anemophilous fungi, which were considered to be contaminants, were also isolated: Penicillium sp. (28 or 21.2 %), Aspergillus sp. (13 or 9.8 %), Rhodotorula sp. (5 or 3.8 %), Candida sp. (5 or 3.8 %), Trichoderma sp. (1 or 0.7 %), and Acremonium sp. (1 or 0.7 %). Due to the low magnitude of occurrence (0.7 %) of Sporothrix in feline claws, the potential of the cats evaluated in this study to be sources of infection in the city of São Paulo is considerably low.

Ornithodoros peropteryx (Acari Argasidae) in Bolivia an argasid tick with a single nymphal stage

By the end of the 1960s, the argasid tick Ornithodoros peropteryx was described from larval specimens collected from the bat Peropteryx macrotis in Colombia. Since its original description, no additional record of O. peropteryx has been reported, and its post-larval stages have remained unknown. During July 2010, 18 larvae were collected from 9 bats (Centronycteris maximiliani), resulting in a mean infestation of 2.0 ± 2.2 ticks per bat (range 1–8). These bats were captured in a farm in northeastern Bolivia close to Guapore´ River in the border with Brazil. Morphological examinations of the larvae revealed them to represent the species O. peropteryx. One engorged larva that was kept alive in the laboratory moulted to a nymph after 9 days. Fourteen days after the larval moulting, the nymph moulted to an adult female without taking any blood meal during the nymphal period. This adult female was used for a morphological description of the female stage of O. peropteryx. In addition, the larvae were used for a morphological redescription of this stage. One larva and two legs extirpated from the adult female were submitted to DNA extraction and PCR targeting a fragment of the mitochondrial 16S rDNA gene, which yielded DNA sequences at least 11 % divergent from any available argasid sequence in Genbank. We show that O. peropteryx ontogeny is characterized by a single, non-feeding, nymphal stage. This condition has never been reported for ticks.

Effects of ischemia and reperfusion on subpopulations of rat enteric neurons expressing the P2X7 receptor

BACKGROUND: Intestinal ischemia followed by reperfusion (I/R) may occur following intestinal obstruction. In rats, I/R in the small intestine leads to structural changes accompanied by neuronal death. AIM: To analyze the impact of I/R injury on different neuronal populations in the myenteric plexus of rat ileum. METHODS: The ileal artery was occluded for 35 min and animals were euthanized 6, 24, and 72 h, and 1 week later. Immunohistochemistry was performed with antibodies against the P2X7 receptor as well as nitric oxide synthase (NOS), calbindin, calretinin, choline acetyltransferase (ChAT), or the pan-neuronal marker anti-HuC/D. RESULTS: Double immunolabeling demonstrated that 100% of NOS-, calbindin-, calretinin-, and ChAT-immunoreactive neurons in all groups expressed the P2X7 receptor. Following I/R, neuronal density decreased by 22.6% in P2X7 receptor-immunoreactive neurons, and decreased by 46.7, 38, 39.8, 21.7, and 20% in NOS-, calbindin-, calretinin-, ChAT-, and HuC/D-immunoreactive neurons, respectively, at 6, 24, and 72 h and 1 week following injury compared to the control and sham groups. We also observed a 14% increase in the neuronal cell body profile area of the NOS-immunoreactive neurons at 6 and 24 h post-I/R and a 14% increase in ChAT-immunoreactive neurons at 1 week following I/R. However, the average size of the calretinin-immunoreactive neurons was reduced by 12% at 6 h post-I/R and increased by 8% at 24 h post-I/R. CONCLUSIONS: This work demonstrates that I/R is associated with a significant loss of different subpopulations of neurons in the myenteric plexus accompanied by morphological changes, all of which may underlie conditions related to intestinal motility disorder