Differential Expression Patterns of N-Acetylglucosaminyl Transferases and Polylactosamines in Uterine Lesions

Polylactosamine (polyLacNAc) is a fundamental structure in glycoconjugates and it is expressed in specific cells/tissues associated with the development and carcinogenesis. β1,3-N-acetylglucosaminyl transferases ((β3GnTs) play an important role in polyLacNAc synthesis, however the roles of these glycosyltransferases and their products in cancer progression are still unclear. In this sense, this work aimed to evaluate differential expression pattern of the N-acetylglucosaminyl transferases and polylactosamines in invasive and premalignant lesions of the uterus cervix. The expression of β3GnT2 and β3GnT3 were evaluated in normal (n=10) and uterine cervix lesions (n=120), both malignant [squamous carcinoma (SC)] and premalignant [cervical intraepithelial neoplasia (CIN), grades 1, 2 and 3] using immunohistochemistry. Besides, lectin histochemistry with Phytolacca americana lectin (PWM) and Wheat germ agglutinin (WGA) was also carried out to observe the presence of polyLacNAc chains and N-acetylglucosamine (GlcNAc), respectively. The β3GnT3 was expressed in almost all samples (99%) and β3GnT2 was higher expressed in disease samples mainly in CIN 3, when compared with normal (P=0.002), CIN 1 (P=0.009) and CIN 2 (P=0.03). The expression of polyLacNAc was higher is SC samples, when compared with normal (P=0.03), CIN 1 (P=0.02) and CIN 3 (P=0.004), and was observed only nuclear expression in nearly 50% of the SC samples, showing a statistically significant when compared with normal (P=0.01), CIN 1 (P=0.002), CIN 2 (P=0.007) and CIN 3 (P=0.04). Deferring from transferases and polyLacNAc chains, GlcNAc (WGA ligand) reveals a gradual staining pattern decrease with the increase of the lesion degree, being more expressed in CIN 1 lesions when compared with normal (P<0.0001), CIN 2 (P<0.0001), SC (P<0.0001) and CIN 3 (P=0.0003). Our data reveal that β3GnT2 and polyLacNAc may be involved in the progression of the pre-malignant lesions of the human uterine cervix. In addition, polyLacNAc expression only in the nucleus can be associated a poor prognostic in uterine lesions.     

Increased nitric oxide production in platelets from severe chronic renal failure patients

Nitric oxide (NO) production occurs through oxidation of the amino acid L-arginine by NO synthase (NOS). NO inhibits platelet activation by increasing the levels of cyclic guanosine monophosphate (cGMP), thus maintaining vascular homeostasis. Our group previously demonstrated (da Silva et al. 2005) an enhancement of the L-arginine-NO-cGMP pathway in platelets taken from chronic renal failure (CRF) patients on haemodialysis associated with reduced platelet aggregation. We investigate the platelet L-arginine-NO-cGMP pathway, platelet function, and inflammation from patients in CRF on conservative treatment. A total of 42 CRF patients and 42 controls (creatinine clearance = 27 ± 3 vs. 93 ± 1 mL per min per 1.73 m2, respectively) participated in this study. NOS activity and expression and cGMP concentration were measured in platelets. Platelet aggregation induced by collagen or ADP was evaluated and plasma levels of fibrinogen were determined by the Clauss method. A marked increase in basal NOS activity was seen in undialysed CRF patients compared with controls, accompanied by an elevation of fibrinogen plasma levels. There were no differences in expression of NOS and in cGMP levels. In this context, platelet aggregation was not affected. We provide the first evidence of increased intraplatelet NO biosynthesis in undialysed CRF patients, which can be an early marker of future haemostatic abnormalities during dialysis treatment.     

Protein kinase C gamma associates directly with the GluR4 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor subunit. Effect on receptor phosphorylation

Ionotropic glutamate receptors mediate the majority of excitatory synaptic transmission in the brain and are thought to be involved in learning and memory formation. The activity of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-type glutamate receptors can be regulated by direct phosphorylation of their subunits, which affects the electrophysiological properties of the receptor, and the receptor association with numerous proteins that modulate membrane traffic and synaptic targeting of the receptor. In the present study we investigated the association of protein kinase C (PKC) gamma isoform with the GluR4 AMPA receptor subunit. PKC gamma was co-immunoprecipitated with GluR4 AMPA receptor subunit in rat cerebellum and in cultured chick retina cell extracts, and immunocytochemistry experiments showed co-localization of GluR4 and PKC gamma in cultured chick retinal neurons. Pull-down assays showed that native PKC gamma binds the GluR4 C-terminal membrane-proximal region, and recombinant PKC gamma was retained by GST-GluR4 C-terminal fusion protein, suggesting that the kinase binds directly to GluR4. Furthermore, GST-GluR4 C-terminal protein was phosphorylated on GluR4 Ser-482 by bound kinases, retained by the fusion protein, including PKC gamma. The GluR4 C-terminal segment that interacts with PKC gamma, which lacks the PKC phosphorylation sites, inhibited histone H1 phosphorylation by PKC, to the same extent as the PKC pseudosubstrate peptide 19-31, indicating that PKC gamma bound to GluR4 preferentially phosphorylates GluR4 to the detriment of other substrates. Additionally, PKC gamma expression in GluR4 transfected human embryonic kidney 293T cells increased the amount of plasma membrane-associated GluR4. Our results suggest that PKC gamma binds directly to GluR4, thereby modulating the function of GluR4-containing AMPA receptors.     

Central 5-HT3 receptor stimulation by m-CPBG increases blood glucose in rats.

The aim of the present study was to investigate the role of central 5-HT3 receptors on the control of blood glucose in stressed and non-stressed rats in both fasted and fed states. Adult Wistar male rats had each their third ventricle cannulated 7 days before the experiments. Injections of m-CPBG, a selective 5-HT3 receptor agonist, induced a significant increase in blood glucose in non-stressed rats in both fasted and in fed states. The same procedure was unable to modify stress-induced hyperglycemia. The hyperglycemic effect of m-CPBG central administration was blocked by pretreatment with ondansetron, a specific 5-HT3 receptor antagonist, indicating that the effects here obtained with m-CPBG were a result of its interaction with 5-HT3 receptors. Third ventricle injections of ondansetron alone were not able to modify blood glucose in non-stressed animals and did not change the hyperglycemic responses observed after immobilization stress. We conclude that pharmacological activation of the central 5-HT3 receptor induces a hyperglycemic effect in non-stressed animals.     

Secret lives of maned wolves (Chrysocyon brachyurus Illiger 1815): as revealed by GPS tracking collars

The maned wolf Chrysocyon brachyurus is a nocturnal and shy species, which has proven difficult to study in the field; consequently, data about its behavioural biology are almost absent from the scientific literature. However, recent advances in global positioning system (GPS) technology mean that it is now possible to study the socio-spatial dynamics of this species in the field. In the present study three related maned wolves (an adult pair and their juvenile female offspring) were monitored by GPS tracking collars for a 6-month period, which included the birth of a litter of pups to the adult pair. The three GPS collars were programmed to record the position of the wearer every 2 h (simultaneously for all three individuals). Analyses of the data from the three individuals showed that the female had the largest home range, then the male and finally the juvenile. Furthermore, there was considerable overlap in home-range use by all three individuals. The home ranges of the adult pair also varied in relation to the birth of pups (decreasing dramatically and then showing a slow increase). During the night, which is the normal period of activity for this species, the three individuals avoided contact with each other. However, during the day, the adult pair usually slept together and their juvenile slept within a few hundred metres of their location. The distance travelled at night was greatest for the female, then the male and finally the juvenile. These data suggest that (1) the social bond between the male and female is strong, (2) maned wolves are highly tolerant of their juvenile offspring, even in the case of new pups being born, and (3) that maned wolves do not hunt together and, in fact, avoid each other when hunting.     

First observations of nest attendance behavior by wild maned wolves,Chrysocyon brachyurus

In many species of canids the male's role in reproduction extends to providing extensive or some parental care to his offspring. Maned wolves are a monogamous canid species whose males have been observed providing parental care to their offspring in captivity, but no field observations exist. We observed a wild pair of maned wolves at their nest site in a period soon after the female had given birth for a total period of 65 days. We made five observation sessions with an average of 3–4 days each separated by approximately 2 weeks. Direct visual observations of maned wolves were made each 30 min during the hours of darkness (17:00–07:00) using night-vision binoculars and confirmed by VHF radiotelemetry. During observations we recorded the location of the male and the female in relation to the nest (i.e., in the nest, nearby or long way from the nest). The results showed that the female spent more than 60.44% of her time in or near the nest. The male spent 28.90% of his time in or near the nest. There was a positive significant correlation between the female and the male in terms of the amount of time spent in or near the nest (P<0.01). The maned wolves showed a strong temporal variation in time spent in or near the nest. In conclusion, our data show that wild male maned wolves—probably—provide parental care through provision of food to their female and presumed offspring rather than “babysitting.” Zoo Biol 28:69–74, 2009. © 2008 Wiley-Liss, Inc.     

Altitudinal distribution and diversity of insects in miombo woodlands in Inhamacari,Manica Province,central Mozambique

To evaluate the role of altitude on distribution pattern and diversity of entomofauna on miombo woodlands, four altitudes (850, 1,000, 1,250 and 1,400 m) were selected in a characteristic mountainous forest of Inhamacari in Mozambique in July 2015. In each sampling altitude, a linear transect with 16 yellow pan traps spaced 2 m apart was established for insect capture. Capture results allowed assessment of insect distribution by determination of insect abundance and relative frequency. Insect diversity estimates were determined by Shannon–Wiener and Simpson indices. Altitude similarity was assessed by the Jaccard coefficient. The chi-square test () was used to compare insect abundance and distribution along the altitudinal gradient. Altitude significantly affected insect abundance, relative frequency and distribution, with a nonlinear decrease with increasing altitude. Families Formicidae (Hymenoptera) and Cecidomyiidae (Diptera) were most dominant. Highest diversity and more families confined to unique altitudinal positions were found at 1,250 m while the lowest diversity was observed at 1,000 m.a.s.l. Among the altitudes, greater similarity was found between 1,000 and 1,400 m. In conclusion, altitude had a significant effect on insect family's distribution. However, further research is recommended in order to understand effect of vegetation composition and structure on insect diversity at different altitudes.