Cystyl aminopeptidase activity in the plasma, viscera and brain of the snake Bothrops jararaca

The relationship between plasma osmolality and cystyl aminopeptidase was characterized in the snake Bothrops jararaca and comparisons were made with the emerging picture of this relationship in rats. The profile of cystyl aminopeptidase activity under basal conditions was determined in the soluble and membrane-bound forms in visceral organs and in the central nervous system in comparison with that of alanyl aminopeptidase. The regional localization of cystyl and alanyl aminopeptidase activities was studied in the central nervous system. The basal level of plasma cystyl aminopeptidase, four- to six-fold higher than in rats, suggests its importance to help regulate circulating levels of neurohypophysial peptides in B. jararaca snake. The osmotic sensitivity of this plasma enzyme, undetectable in male, but about three-fold higher in female snakes than in rats, reveals a sexual dimorphism. In marked contrast to those observed in rats, low levels of soluble and particulate forms in the kidney indicate that cystyl aminopeptidase plays a minor metabolizing role at this anatomical location in B. jararaca. Despite of the regional-specific divergence between the levels of rat and snake enzymes, the bilaterally symmetric pattern of the diencephalic distribution of alanyl aminopeptidase reflects functional homologies between these two distantly related species.     

Morphological effects of oestradiol-17beta, and selective oestrogen receptor alpha and beta agonists on luteinising hormone-secreting cells in tamoxifen-treated ovariectomised rats

To investigate the role played by the different rat gonadotroph oestrogen receptor (ER) pools in the effects of oestradiol-17beta (E2) on gonadectomy cells, two-week ovariectomised (OVX) rats were used. The basic experimental group of rats was injected with 3 mg of the selective ER modulator tamoxifen (TX) on days 15-20 after OVX. Groups of TX-treated OVX rats were additionally injected on days 18-20 after OVX with 10 microg oestradiol benzoate (EB), 1 mg of the selective ERalpha agonist propylpyrazole triol (PPT), or 1 mg of the selective ERbeta diarylpropionitrile (DPN). Negative and positive control groups were OVX rats injected over six days after OVX with 0.2 ml oil and EB, respectively. On day 21 after OVX, anterior pituitary glands were dissected out and divided into halves. One hemipituitary was processed for light microscopy and immunocytochemistry for betaLH subunit and progesterone receptor (PR), and the other hemipituitary for ultrastructural evaluation. Results showed that: gonadotrophs were the only pituitary cell type expressing PR; treatment with TX alone shrunk gonadectomy cells and induced both reorganization of membrane-enclosed intracellular organelles and PR expression, and treatment with DPN or EB, but not PPT, reduced the agonistic morphological effects of TX. Considering that TX activates nuclear ERalpha, the results indicate that activation of nuclear ERalpha is determinant for the reversal effects of E2 on gonadotrope morphology and PR expression, and the simultaneous activation of ERbeta modulates the action of ERalpha in an inhibitory fashion.     

Quantification of Inter-particle Spacing Caused by Thiol Self-Assembled Monolayers Using Transmission Electron Microscopy

Plasmonics - Nano-surface modification techniques have been increasingly reported in a multitude of applications. However, the metal-ligand interface can be difficult to characterize, mainly due to...     

DNA Barcoding of Neotropical Sand Flies (Diptera,Psychodidae, Phlebotominae): Species Identification and Discovery within Brazil

DNA barcoding has been an effective tool for species identification in several animal groups. Here, we used DNA barcoding to discriminate between 47 morphologically distinct species of Brazilian sand flies. DNA barcodes correctly identified approximately 90% of the sampled taxa (42 morphologically distinct species) using clustering based on neighbor-joining distance, of which four species showed comparatively higher maximum values of divergence (range 4.23–19.04%), indicating cryptic diversity. The DNA barcodes also corroborated the resurrection of two species within the shannoni complex and provided an efficient tool to differentiate between morphologically indistinguishable females of closely related species. Taken together, our results validate the effectiveness of DNA barcoding for species identification and the discovery of cryptic diversity in sand flies from Brazil.     

Ethnobotany in a coastal environmental protected area: shifts in plant use in two communities in southern Brazil

Background

We investigated local knowledge of plants in terms of plant use shifts and losses, in two coastal communities within a protected area in southern Brazil. Our hypothesis is that people’s livelihoods are associated with different ethnobotanical knowledge, and changes in these activities can reflect shifts in ethnobotanical knowledge such as stopping using some plants.

Methods

We interviewed 125 inhabitants after prior informed consent, asking her/him about their socioeconomic profile and to free list the plants they know. The free lists were analyzed by frequency of cited plants. To compare averages of cited plants and age in both communities, we used the Wilcoxon test with a significance of 5%. Spearman correlation was tested with number of plants cited in the past and the interviewees’ age. Permanence and change in economic activities in each community were represented using a graph and compared through a chi-squared test with a significance of 5%. Qualitative analyses of the interviews and a field diary were used to analyze driving forces for the abandonment of used plants.

Results

We identified 231 plant species that were currently used mainly for food and medicine. Despite being in a protected area, most of the cited plants were exotic and cultivated in home gardens. We do not confirm the hypothesis that changes in livelihoods are reflected in the plants used; however, qualitative analyses showed potential drivers for shifts and losses of plant use. “Environmental law” and “protected area” were the drivers most related to the abandonment of plant use.

Conclusions

While recognizing the importance of the protected area to maintain local people and their traditions, we documented a shift in plant use that is mainly correlated to construction activities that disappeared from daily practices.

     

Hyperglycemia and aberrant <Emphasis Type="Italic">O-GlcNAc</Emphasis>ylation: contributions to tumor progression

A number of cancer types have shown an increased prevalence and a higher mortality rate in patients with hyperglycemic associated pathologies. Although the correlation between diabetes and cancer incidence has been increasingly reported, the underlying molecular mechanisms beyond this association are not yet fully understood. Recent studies have suggested that high glucose levels support tumor progression through multiple mechanisms that are hallmarks of cancer, including cell proliferation, resistance to apoptosis, increased cell migration and invasiveness, epigenetic regulation (hyperglycemic memory), resistance to chemotherapy and altered metabolism. Most of the above occur because hyperglycemia through hexosamine biosynthetic pathway leads to aberrant O-GlcNAcylation of many intracellular proteins that are involved in those mechanisms. Deregulated O-GlcNAcylation is emerging as a general feature of cancer. Despite strong evidence suggesting that aberrant O-GlcNAcylation is or may be involved in the acquisition of all cancer hallmarks, it remains out of the list of the next generation of emerging hallmarks. Here, we discuss some of the current understanding on how hyperglycemia affects cancer cell biology and how aberrant O-GlcNAcylation stands in this context.     

The effect of a myocardial infarction on the normalized time-varying elastance curve.

It has been suggested that the shape of the normalized time-varying elastance curve [E(n)(t(n))] is conserved in different cardiac pathologies. We hypothesize, however, that the E(n)(t(n)) differs quantitatively after myocardial infarction (MI). Sprague-Dawley rats (n = 9) were anesthetized, and the left anterior descending coronary artery was ligated to provoke the MI. A sham-operated control group (CTRL) (n = 10) was treated without the MI. Two months later, a conductance catheter was inserted into the left ventricle (LV). The LV pressure and volume were measured and the E(n)(t(n)) derived. Slopes of E(n)(t(n)) during the preejection period (alpha(PEP)), ejection period (alpha(EP)), and their ratio (beta = alpha(EP)/alpha(PEP)) were calculated, together with the characteristic decay time during isovolumic relaxation (tau) and the normalized elastance at end diastole (E(min)(n)). MI provoked significant LV chamber dilatation, thus a loss in cardiac output (-33%), ejection fraction (-40%), and stroke volume (-30%) (P < 0.05). Also, it caused significant calcium increase (17-fold), fibrosis (2-fold), and LV hypertrophy. End-systolic elastance dropped from 0.66 +/- 0.31 mmHg/microl (CTRL) to 0.34 +/- 0.11 mmHg/microl (MI) (P < 0.05). Normalized elastance was significantly reduced in the MI group during the preejection, ejection, and diastolic periods (P < 0.05). The slope of E(n)(t(n)) during the alpha(PEP) and beta were significantly altered after MI (P < 0.05). Furthermore, tau and end-diastolic E(min)(n) were both significantly augmented in the MI group. We conclude that the E(n)(t(n)) differs quantitatively in all phases of the heart cycle, between normal and hearts post-MI. This should be considered when utilizing the single-beat concept.     

Differential Targeting of SLC30A10/ZnT10 Heterodimers to Endolysosomal Compartments Modulates EGF‐Induced MEK/ERK1/2 Activity

The solute carrier 30A (SLC30A) family of zinc exporters transports zinc into the lumen of intracellular organelles in order to prevent zinc toxicity. We reported that formation of tyrosine dimers is required for ZnT3 (zinc transporter 3) zinc transport activity and targeting to synaptic‐like microvesicles (SLMVs) in PC12 cells and the formation of ZnT3/ZnT10 heterodimers. Here, we focused on ZnT10 to determine the role of heterodimerization in the sorting of ZnTs in the endolysosomal pathway. Using cell fractionation, immunoprecipitation and immunofluorescence approaches, we found that ZnT10 resides in transferrin receptor and Rab5‐positive endosomes and forms covalent heterodimers and oligomers with ZnT2, ZnT3 and ZnT4. The interaction of ZnT10 with ZnT3, mediated by dityrosine bonds, was unable to target ZnT10 into SLMVs in vitro or into synaptic vesicles isolated from mouse brain in vivo. However, ZnT3/ZnT10 heterodimers regulate epidermal growth factor receptor (EGF‐R) signaling by increasing the phosphorylation of mitogen‐activated protein kinase kinase (MEK) and extracellular signal‐regulated kinase (ERK1/2), but not EGF‐R, C‐Raf or Akt phosphorylation in response to EGF. Further, mutation of tyrosine 4 in ZnT10 reduced ZnT3/ZnT10 dityrosine‐mediated heterodimerization and zinc transport, as well as MEK and ERK1/2 phosphorylation, which were also reduced by the zinc chelator TPEN. Phosphorylation of these kinases is likely to occur in the cytosol as no differences in phosphorylation were observed in membrane fractions of control and ZnT3/ZnT10‐expressing cells. We propose that ZnT10 plays a role in signal transduction, which is mediated by homo and heterodimerization with other ZnTs.      

Therapeutic efficacy in BALB/C mice of extract from marine alga <Emphasis Type="Italic">Canistrocarpus cervicornis</Emphasis> (Phaeophyceae) against herpes simplex virus type 1

Studies with diterpenes from marine brown alga Canistrocarpus cervicornis showed the antiviral potential of the products from this alga in controlling the replication of HSV-1 and maintaining low cytotoxicity. Hence, the aim of this work was to evaluate the anti-herpetic efficacy of C. cervicornis extract ointment in BALB/c mice. To test the anti-herpetic efficacy in vivo, four groups of BALB/c mice (n?=?5) were used: 1—untreated, 2—extract ointment (2 % or 0.4 mg cm^?2 dose^?1), 3—Acyclovir cream (5 % or 1.0 mg cm^?2 dose^?1), and 4—ointment base. The right midflank of each mouse was clipped and depilated with a chemical depilatory. After 2 days, the skin area was scratched and inoculated with HSV-1. The ointments and cream were applied three times a day over a 16-day period, beginning 1 h after virus inoculation. The development of skin lesions was continuously monitored and scored. To evaluate the effect of C. cervicornis topical treatment on biochemical parameters and on body weight, two uninfected groups were formed: an untreated group and a group treated with ointment C. cervicornis extract (2 %). The signs of infection appeared from the second day after infection, while on the 10th day of the experiment, the ointment base and untreated groups had significantly more severe lesions than did the groups that were treated with extract (p?<?0.05) or acyclovir (p?<?0,01). The topical application of extract ointment did not change body weight, hepatic, or renal function suggesting that the extract has a low toxicity in this route of administration. These results suggest that the extract may be useful in reducing the severity of HSV-1 cutaneous lesions.