Ion-exchange voltammetry and electrocatalytic sensing capabilities of cytochrome c at polyestersulfonated ionomer coated glassy carbon electrodes

The incorporation and electrochemical behaviour of cytochrome c (Cyt C) at glassy carbon electrodes modified with the polyestersulfonated ionomer Eastman AQ 55 are examined. The presence of the polyelectrolytic coating allows the preconcentration of the protein within the polymer and the observation of the direct electrochemistry of Cyt C at the modified electrode without addition of promoters or mediators in the solutions. The dependence of voltammetric signals on typical parameters such as solution pH and nature or concentration of the supporting electrolyte supports the ion-exchange nature of the incorporation process. The relevant role of the permselectivity of the polymeric modifier is highlighted also by the study of electrocatalytic processes which take place at the modified electrode loaded with Cyt C. No electrocatalytic effect is observed when the electrogenerated dication (ferricenylmethyl)trimethylammonium is present as possible oxidant. On the contrary, electrocatalytic current enhancements are observed for anionic substrates such as Fe(CN)(6)(3-) (oxidant) and ascorbate (reductant). Catalytic currents increase with the substrate concentration, with higher sensitivity for Fe(CN)(6)(3-). Due to ionic repulsion, the reaction with anions occurs at the polymer-solution interface. In the case of chemically unstable substrates, such as superoxide anion, ionic repulsion slow down the approach rate of the substrate so that spontaneous decomposition can prevail over the reaction with Cyt C incorporated in the coating.     

Purification of p47f,a Necrosis‐Inducing Protein Fraction from the Secretome of Phytophthora capsici

The oomycete Phytophthora capsici causes wilting disease in chilli pepper and another solanaceous plants, with important economic consequences. Although much investigation has been conducted about this pathogen, little is still known about which of its proteins are involved in the infection process. In this study, the bioassay‐guided fractionation of the secretome of P. capsici resulted in the purification of a phytotoxic protein fraction designated as p47f, capable of inducing wilting and necrosis on leaves of Capsicum chinense Jacq, and having a 47 kDa polypeptide with proteolytic activity as the major component. The isolated p47f fraction induced DNA degradation and decreased cell survival of C. chinense cell suspension culture. Sequencing of p47f indicated the presence of 15 proteins, which could be grouped into seven classes including a protease group, cell wall remodelling proteins and the transglutaminase elicitor M81D, among others. This is the first report of P. capsici secreting proteins that modulate cell responses mediated by ROS in the host.     

Follow-up assessment of patients with Pure Neural Leprosy in a reference center in Rio de Janeiro—Brazil

IntroductionPure Neural Leprosy (PNL) is a rare clinical form of leprosy in which patients do not present with the classical skin lesions but have a high burden of the disability associated with the disease. Clinical characteristics and follow up of patients in PNL are still poorly described in the literature.ObjectiveThis paper aims to describe the clinical, electrophysiological and histopathological characteristics of PNL patients, as well as their evolution after multidrug therapy (MDT).MethodsFifty-two PNL patients were selected. Clinical, nerve conduction studies (NCS), histopathological and anti-PGL-1serology were evaluated. Patients were also assessed monthly during the MDT. At the end of the MDT, all of the patients had a new neurological examination and 44 were submitted to another NCS.ResultsParesthesia was the complaint most frequently reported by patients, and in the neurological examination the most common pattern observed was impairment in sensory and motor examination and a mononeuropathy multiplex. Painful nerve enlargement, a classical symptom of leprosy neuropathy, was observed in a minority of patients and in the motor NCS axonal injuries, alone or in combination with demyelinating features, were the most commonly observed. 88% of the patients did not present any leprosy reaction during MDT. There was no statistically significant difference between the neurological examinations, nor the NCS pattern, performed before and after the MDT.DiscussionThe classical hallmarks of leprosy neuropathy are not always present in PNL making the diagnosis even more challenging. Nerve biopsy is an important tool for PNL diagnosis as it may guide therapeutic decisions. This paper highlights unique characteristics of PNL in the spectrum of leprosy in an attempt to facilitate the diagnosis and management of these patients.     

Factors Associated with Low Levels of HIV Testing among Men Who Have Sex with Men (MSM) in Brazil

The aim of this study was to assess risk factors associated with low levels of HIV testing among MSM recruited through respondent driven sampling (RDS) in Brazil. Of 3,617 participants, 48.4% had never tested previously for HIV. A logistic model indicated that younger age, lower socioeconomic class, education, poor HIV/AIDS knowledge, no history of cruising, and having been tested during the study were characteristics independently associated with low levels of previous HIV testing. The HIV testing rate among MSM in Brazil is still low in spite of the availability of a large number services providing universal and free access to HIV/AIDS diagnosis and treatment. To respond to low utilization, the authors propose a higher priority for testing for key populations such as MSM, expanded education, expanding testing sites and a welcoming and nonjudgmental environment in health services.     

Urinary markers of nephrotoxicity following administration of 2 bromoethanamine hydrobromide a comparison with hexachlorobutadiene

2 bromoethanamine hydrobromide (BEA) has been widely considered to be a target selective nephrotoxin that causes necrosis of the medulla in 24-48 h, but recent reports suggest that early cortical injury is also associated with this lesion. In order to assess the cortical effects of BEA (100 mg kg^-1 bw single ip injection), several urinary markers of renal injury were evaluated over a 7 day period in male Wistar Albino rats. Hexachlorobutadiene (HCBD 150 mg kg^-1 bw in peanut oil ip), a renal toxin which targets selectively for the proximal tubule, was used as a comparison. After BEA treatment, urinary levels of alanine aminopeptidase, gamma-glutamyl-transpeptidase, alkaline phosphatase and glucose increased transiently. Each of the proximal tubule marker enzymes peaked earlier following HCBD treatment and elevation of alanine aminopeptidase and gamma glutamyl transpeptidase was sustained for longer periods than for BEA. Following BEA treatment, lactate dehydrogenase rose prominently on day 1 followed by a return to control values on day 2 and a further rise on day 3 and remained high until the end of the study. BEA also increased the urinary excretion of total protein and albumin. After HCBD treatment, lactate dehydrogenase showed a transient elevation and glucose levels were slightly increased. Based on the present observations the changes induced by BEA administration on urinary markers of renal injury are different from those observed following HCBD treatment. These findings suggest that BEA toxicity also involves other parts of the kidney besides the papilla.     

Architectural models for apical patterns in Gelidium (Gelidiales, Rhodophyta): hypothesis of growth

The great morphological variation in the apical region of main axes and branches in species of Gelidium and Pterocladia suggests different patterns of growth. Those patterns have been reconstructed from the ontogenetic sequence of morphological stages and regeneration of the apex. Using the architectural approach, models for four species of Gelidium from the Pacific coast of central Chile and the Pacific coast of Mexico's tropical region, were constructed based on the following criteria: growth pattern, specialization of laterals, symmetry, apical dominance and rhythm of apical and lateral growth. Those models allow for a formal evaluation of apical differences between species.     

Polyamines modify the components of phospholipids-based signal transduction pathway in Coffea arabica L. cells.

Recent results, fundamentally obtained from animal tissues, suggest that polyamines (Pas), essential compounds for the growth and development of all life organisms, may interact with a signal transduction cascade. Because Pas are highly positive charged compounds, their binding with phospholipids involved in signal transduction is likely to be the case. In this work, the in vivo effect of Pas on some important components of phospholipid signal transduction pathway was studied, by the first time, in plant tissue. Endogenous Pas content varied during the culture cycle of Coffea arabica cells: putrescine (Put) levels increased at the end of the stationary phase, both spermidine (Spd) and spermine (Spm) accumulated at the beginning of the linear growth phase. Cells that were incubated with Put presented a significant increase in phospholipase D (PLD) (EC: 3.1.4.4) activity, phospholipase C (PLC) (EC: 3.1.4.3) activity decreased, and the effect on lipid kinases was less marked. However, the incubation of the cells with Spd and Spm significantly stimulated the lipid kinases activities, fundamentally increased the formation of phosphatidyl inositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2), while the effect on PLC and PLD activities was minor when compared with the cells treated with Put. The results presented here suggest that Pas may modulate the cellular signal of C. arabica cells by differentially affecting components of the phospholipid cascade.