Development of Rhodnius prolixus (Hemiptera: Reduviidae) under Constant and Cyclic Conditions of Temperature and Humidity

Development of Rhodnius prolixus after eclosion until the adult stage was studied at constant temperatures (T), 15, 20, 25, 28, 35°C, and relative humidities (RH), 75, 86 and 97%, and fluctuating (16/8 hr) temperatures, T I/II, 15/28°C, 20/25°C, 25/28°C and 25/35°C, and relative humidities, RH I/II, 86/75% and 97/75%. Eclosion or molting were not observed at 15°C and 86 or 97% RH, respectively. At 35°C and 75% RH only few insects molted. By alternating T I/II, 15/28°C and 25/35°C, insects developed at high frequency. Cumulating the average lengths of the interphases within independent groups for each instar, R. prolixus reached the adult stage most rapidly (86.7 days) and at highest frequency per instar (mean: 91.8%) at 28°C and 75% RH. Under fluctuating T I/II, development was completed within 100 days or less at 25/28°C and 25/35°C with high rates of hatch and molting. Development was slowest at fluctuating TI/II, 15/28°C and 20/25°C (>185 days), and at constant 20°C (>300 days). Mortality was higher at constant 97% RH or fluctuating RH I, 97%, than at constant or fluctuating 86% RH. Refeeding was minimal at optimal conditions of T and RH for development. The most refeeding was observed at a constant 35°C.

Cyclic 3'-5' guanosine monophosphate-dependent activity in Leishmania amazonensis

Although there are some data concerning the nitric oxide and the cyclic 3'-5'guanosine monophosphate (cGMP) signaling pathway in trypanosomatids, there is no report about the cGMP-dependent enzymatic activity identification. In this sense, a cGMP dependent activity was detected on soluble fraction from Leishmania amazonensis promastigotes with a high metacyclic level. This information is valuable in order to explore the metabolic pathway of G kinase protein in this parasite.

Polymers as carriers for rhizobial inoculant formulations

The aim of this work was to evaluate the efficiency of carboxymethyl cellulose (CMC) and starch blends as carrier materials of rhizobial inoculants regarding their capacity to maintain viable cells and promote cowpea (Vigna unguiculata) nodulation. The experimental design adopted was completely randomized, with three replicates. Forty different compositions of carboxymethyl cellulose (CMC) with starch, compatibilized or not with different proportions of MgO or ZnO, were evaluated regarding their ability of maintaining rhizobial viable cells during the storage period of one month at room temperature, in an initial screening. Thereafter, selected inoculant carrier blends were evaluated regarding their ability to maintain viable rhizobial cells for a period of 165 days, and their performance as inoculant carriers was compared to a peat-based inoculant carrier under greenhouse conditions. Rhizobial cells were better maintained in blends containing 50-60% CMC. Compatibilizing agents did not increase survival of rhizobial cells for 30 days of storage. The cowpea nodulation of polymer blends was statistically the same of peat-based inoculants. CMC/starch polymer blends are efficient carriers to rhizobial inoculants for up to 165 days of storage, when compatibilized with MgO (1%).

Influência da acidez do meio sobre a síntese e o comportamento redox do polipirrol

The influence of acidity on the synthesis and redox behavior of polypyrrole films was studied using galvanostatic and potentiodynamic techniques employing aqueous solutions formed by H2SO4/Na2SO4 , HCl/NaCl and HCl/CsCl. The chemical structure of the films were investigated using the FTIR technique. The polymer behavior as a function of the pH used in the cyclic voltammetric measurements is explained in terms of the mechanism responsible for the charge compensation formed during the polymer chain oxidation. From the FTIR measurements, it is seen that the water nucleophilic attack during the synthesis, does not occur under the experimental conditions employed in this work.

Polímeros biomiméticos em química analítica. Parte 1: preparo e aplicações de MIP ("Molecularly Imprinted Polymers") em técnicas de extração e separação

MIPs are synthetic polymers that are used as biomimetic materials simulating the mechanism verified in natural entities such as antibodies and enzymes. Although MIPs have been successfully used as an outstanding tool for enhancing the selectivity or different analytical approaches, such as separation science and electrochemical and optical sensors, several parameters must be optimized during their synthesis. Therefore, the state-of-the-art of MIP production as well as the different polymerization methods are discussed. The potential selectivity of MIPs in the extraction and separation techniques focusing mainly on environmental, clinical and pharmaceutical samples as applications for analytical purposes is presented.

Polímeros biomiméticos em química analítica. Parte 2: aplicações de MIP ("Molecularly Imprinted Polymers") no desenvolvimento de sensores químicos

The aim of this paper is the description of the strategies and advances in the use of MIP in the development of chemical sensors. MIP has been considered an emerging technology, which allows the synthesis of materials that can mimic some highly specific natural receptors such as antibodies and enzymes. In recent years a great number of publications have demonstrated a growth in their use as sensing phases in the construction of sensors . Thus, the MIP technology became very attractive as a promising analytical tool for the development of sensors.

Stereoselective syntheses of (+)- isoretronecanol and (+)-5-epi-tashiromine via addition of chiral titanium (iv) enolates to cyclic n-acyliminium ions

The stereoselective addition of the titanium (IV) enolates derived from (S)-4-isopropyl-N-4-chlorobutyryl-1,3-thiazolidine-2-thione (8) and from (S)-4-isopropyl-N-4-chloropentanoyl-1,3-thiazolidine-2-thione (9) to N-Boc-2-methoxypyrrolidine (5b) afforded the addition products (+)-10 and (+)-11 in 84% yield in both cases, as 8.6:1 and 10:1 diastereoisomeric mixtures, respectively. A three-step sequence allowed to convert these adducts to (+)-isoretronecanol (1) and (+)-5-epi-tashiromine (2) in 43% and 49% overall yield, respectively.

Aplicação de ciclodextrinas em processos têxteis

Cyclodextrins (CDs) are water soluble cyclic sugars with a hydrophobic nanometric cavity that permits the formation of host/guest inclusion complexes with a large variety of molecules, alternating their physical-chemical properties. In the present review CD research related to the processing of textiles is revised and discussed. CDs may function as encapsulating, dispersing and levelling agents in the dyeing and washing of textiles. Furthermore they may be anchored to polymers and textile fibers in order to impart special properties such as odor reduction, UV protection or for the controlled release of perfumes, aromas, mosquito repellents or substances with therapeutical effects.

Poly(o-methoxyaniline) modified electrode for detection of lithium ions

This paper reports the use of an electrode modified with poly(o-methoxyaniline) for detecting lithium ions. These ions are present in drugs used for treating bipolar disorder and that requires periodical monitoring of the concentration of lithium in blood serum. Poly(o-methoxyaniline) was obtained electrochemically by cyclic voltammetry on the surface of a gold electrode. The results showed that the electrode modified with a conducting polymer responded to lithium ions in the concentration range of 1 x 10-5 to 1 x 10-4 mol L-1 . The results also confirmed that the performance of the modified electrode was comparable to that of the standard method (atomic emission spectrophotometry).

Romp as a versatile method for the obtention of differentiated polymeric materials

Ring Opening Metathesis Polymerization (ROMP) of cyclic olefins is a powerful transition metal-catalyzed reaction for syntheses of polymers and copolymers. The key feature of this reaction is the [2+2]-cycloaddition mechanism, with retention of the olefinic unsaturation in the polymer chain and occurrence of living polymerization. With the development of metal-carbene type catalysts for this process, many addressed polymeric materials have been successfully prepared to be employed in several fields of the science and technology. This review summarizes recent examples of syntheses of polymers with amphiphilic features such as block, graft, brush or star copolymers; as well syntheses of biomaterials, dendronized architectures, photoactive polymers, cross-linked or self-healing materials, and polymers from renewed supplies.

Use of new silica fillers as additives for polymers used in packaging of fruit

The objective of this work was to synthesize nanosilicas with different degree of hydrophobicity by the sol-gel method, using tetraethyl orthosilicate as a precursor. For this purpose, 3-aminopropyl triethoxysilane (APS) and 1,1,1,3,3,3 - hexamethyldisilazane (HMDS), were added during synthesis as modifiers. A commercial biopolymer (Hexamoll Dinch, BASF) intended for packaging of apples, was added to the new nanosilicas. The materials obtained were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, potentiometric titration, porosity, specific surface area and hydrophobicity/hydrophilicity by wetting test. Colorimetry was used to evaluate change in apple pulp color after contact with the different silicas.

Chiral separations of mandelic acid by HPLC using molecularly imprinted polymers

Styrene is used in a variety of chemical industries. Environmental and occupational exposures to styrene occur predominantly through inhalation. The major metabolite of styrene is present in two enantiomeric forms, chiral R- and S- hydroxy-1-phenyl-acetic acid (R-and S-mandelic acid, MA). Thus, the concentration of MA, particularly of its enantiomers, has been used in urine tests to determine whether workers have been exposed to styrene. This study describes a method of analyzing mandelic acid using molecular imprinting techniques and HPLC detection to perform the separation of diastereoisomers of mandelic acid. The molecularly imprinted polymer (MIP) was prepared by non-covalent molecular imprinting using (+) MA, (-) MA or (+) phenylalanine, (-) phenylalanine as templates. Methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) were copolymerized in the presence of the template molecules. The bulk polymerization was carried out at 4ºC under UV radiation. The resulting MIP was grounded into 25~44¼m particles, which were slurry packed into analytical columns. After the template molecules were removed, the MIP-packed columns were found to be effective for the chromatographic resolution of (±)-mandelic acid. This method is simpler and more convenient than other chromatographic methods.

Morphological features and vascularization study of caprine cyclic corpus luteum

Corpus luteum is a temporary endocrine gland that regulates either the estrous cycle and pregnancy. It presents extreme dependency on the adequate blood supply. This work aims to evaluate goat corpus luteum (CL) vascular density (VD) over the estrous cycle. For that purpose, 20 females were submitted to estrus synchronization/ovulation treatment using a medroxyprogesterone intra-vaginal sponge as well as intramuscular (IM) application of cloprostenol and equine chorionic gonadotrophine (eCG). After sponge removal, estrus was identified at about 72hs. Once treatment was over, female goats were then subdivided into 4 groups (n=5 each) and slaughtered on days 2, 12, 16 and 22 after ovulation (p.o). Ovaries were collected, withdrawn and weighted. CL and ovaries had size and area recorded. Blood samples were collected and the plasma progesterone (P4) was measured through RIA commercial kits. The VD was 24.42±6.66, 36.26±5.61, 8.59±2.2 and 3.97±1.12 vessels/mm² for days 2, 12, 16 and 22 p.o, respectively. Progesterone plasma concentrations were 0.49±0.08, 2.63±0.66, 0.61±0.14 and 0.22±0.04ng/ml for days 2, 12, 16 e 22 p.o, respectively. Studied parameters were affected by the estrous cycle phase. Values greater than 12 p.o were observed. In the present work we observed that ovulation occurred predominantly in the right ovary (70% of the animals), which in turn presented bigger measures than the contra lateral one. There is a meaningful relationship between the weight and size of the ovary and these of CL (r=0.87, r=0.70, respectively, p<0.05). It is possible to conclude that morphology of goat's ovaries and plasma progesterone concentration changed according to estrous cycle stages. We propose these parameters can be used as indicators of CL functional activity.

Cellular signaling with nitric oxide and cyclic GMP

During the past two decades, nitric oxide signaling has been one of the most rapidly growing areas in biology. This simple free radical gas can regulate an ever growing list of biological processes. In most instances nitric oxide mediates its biological effects by activating guanylyl cyclase and increasing cyclic GMP synthesis. However, the identification of effects of nitric oxide that are independent of cyclic GMP is also growing at a rapid rate. The effects of nitric oxide can mediate important physiological regulatory events in cell regulation, cell-cell communication and signaling. Nitric oxide can function as an intracellular messenger, neurotransmitter and hormone. However, as with any messenger molecule, there can be too much or too little of the substance and pathological events ensue. Methods to regulate either nitric oxide formation, metabolism or function have been used therapeutically for more than a century as with nitroglycerin therapy. Current and future research should permit the development of an expanded therapeutic armamentarium for the physician to manage effectively a number of important disorders. These expectations have undoubtedly fueled the vast research interests in this simple molecule.