Capacidad de enraizamiento de plantas matrices promisorias de Myrciaria dubia (Kunth) Mc Vaugh en cámaras de subirrigación¹

Camu camu es una fruta nativa de la Amazonía, que llama la atención por el alto contenido de vitamina C (6,116 mg/ 100 g de pulpa), está en proceso de domesticación, por lo cual se está investigando un método de propagación vegetativa que permita avanzar en el proceso de mejoramiento genético. El objetivo de este trabajo fue evaluar la capacidad rizogénica de plantas matrices promisorias de camu camu "Myrciaria dubia (Kunth) McVaugh" según el aumento del número de hojas, mediante la técnica de estacas herbáceas en cámaras de subirrigación. El ensayo fue conducido mediante un Diseño de Bloques Completamente al Azar (DBCA) con arreglo factorial 9Ax3B, con 3 repeticiones y 15 estacas por unidad experimental. El factor A, estuvo constituido por nueve plantas matrices y el factor B: pares de hojas con 3 niveles: 1; 2 y 3 pares. El enraizamiento fue evaluado después de 90 días. Se observó que existió interacción estadística significativa para las variables: porcentaje de enraizamiento, longitud y número de raíces. Para las variables porcentaje de callo y porcentaje de mortalidad se encontró efecto de la planta matriz y pares de hojas. Los resultados muestran que el porcentaje de enraizamiento estuvo influenciado por efectos intrínsecos adherentes a la variabilidad genotípica de las plantas matrices, presentando un alto grado de dispersión, que osciló entre 91,11 % y 0,00 %, mostrando una alta variabilidad y marcada influencia de la planta matriz sobre el proceso de rizogénesis, influyendo de manera altamente significativa en el enraizamiento. Con respecto al área foliar, estacas con 2 y 3 pares de hojas, independiente de la planta matriz, presentaron mayor capacidad de enraizamiento. Con base en estos resultados se concluye que el efecto de la variabilidad genotípica y el área foliar influyen de manera altamente significativa en el proceso de rizogénesis de estacas herbáceas de camu camu.

Evaluation of HA negatively charged membranes in the recovery of human adenoviruses and hepatitis A virus in different water matrices

Human adenoviruses (HAdV) and hepatitis A virus (HAV) are shed in the faeces and consequently may be present in environmental waters, resulting in an increase in pathogen concentration that can affect water quality and human health. The aim of this study was to evaluate an adsorption-elution method which utilizes negatively charged membrane HA to determine the efficient recovery of HAdV and HAV from different water matrices and to combine this procedure with a qualitative molecular method (nested RT-PCR and nested PCR). The best efficiency recovery was achieved in distilled water and treated wastewater effluent (100%) for both viruses and in recreational lagoon water for HAV (100%). The efficiency recovery was 10% for HAdV and HAV in seawater and 10% for HAdV in lagoon water. The viral detection limit by nested PCR for HAV in water samples ranged between 20-0.2 FFU/mL and 250 and 25 TCID50/mL for HAdV. In conclusion, these results suggest that the HA negatively charged membranes vary their efficiency for recovery of viral concentration depending upon the types of both enteric viruses and water matrices.

Solid phase extraction of iron and lead in environmental matrices on amberlite xad-1180/pv

A solid phase extraction procedure using Amberlite XAD-1180/Pyrocatechol violet (PV) chelating resin for the determination of iron and lead ions in various environmental samples was established. The procedure is based on the sorption of lead(II) and iron(III) ions onto the resin at pH 9, followed by elution with 1 mol/L HNO3 and determination by flame atomic absorption spectrometry. The influence of alkaline, earth alkaline and some transition metals, as interferents, are discussed. The recoveries for the spiked analytes were greater than 95%. The detection limits for lead and iron by FAAS were 0.37 µg/L and 0.20 µg/L, respectively. Validation of the method described here was performed by using three certified reference materials (SRM 1515 Apple Leaves, SRM 2711 Montana Soil and NRCC-SLRS-4 Riverine Water). The procedure was successfully applied to natural waters and human hair.

A low-cost ultrasonic spray dryer to produce spherical microparticles from polymeric matrices

The spray-drying technique has been widely used for drying heat-sensitive foods, pharmaceuticals, and other substances, because it leads to rapid solvent evaporation from droplets. This method involves the transformation of a feed from a fluid state into a dried particulate, by spraying the feed into a hot medium. Despite being most often considered a dehydration process, spray drying can also be used as an encapsulation method. Therefore, this work proposes the use of a simple and low-cost ultrasonic spray dryer system to produce spherical microparticles. This equipment was successfully applied to the preparation of dextrin microspheres on a laboratory scale and for academic purposes.

Un método de bajo costo para la determinación de cobre a nivel de vestigios en matrices de interés ambiental por espectrofotometría en fase sólida (EFS)

A method for determining copper by solid phase spectrophotometry (SPS) was optimized using the Doehlert design. Copper(II) was sorbed on a styrene-divinylbenzene anion-exchange resin as a Cu(II)-1-(2-pyridylazo)-2-naphthol (PAN) complex, at pH 7.0. Resin phase absorbances at 560 and 800 nm were measured directly. The detection limit was found to be 2.5 µg L-1. The relative standard deviation on ten replicate determinations of 10 µg Cu(II) in 1000 mL samples was 1.1%. The linear range of the determination was 5.0-100 µg L-1. The method was applied successfully to the determination of Cu(II) in natural water and vegetable samples.

Instability of a square sheet under symmetric biaxial loading

An early experiment found that a square rubber sheet under symmetric biaxial loading may not remain square. This curious result has been one of the most instructive examples in finite elasticity. Here thermodynamic considerations are used to analyze this instability.

Building bone tissue: matrices and scaffolds in physiology and biotechnology

Deposition of bone in physiology involves timed secretion, deposition and removal of a complex array of extracellular matrix proteins which appear in a defined temporal and spatial sequence. Mineralization itself plays a role in dictating and spatially orienting the deposition of matrix. Many aspects of the physiological process are recapitulated in systems of autologous or xenogeneic transplantation of osteogenic precursor cells developed for tissue engineering or modeling. For example, deposition of bone sialoprotein, a member of the small integrin-binding ligand, N-linked glycoprotein family, represents the first step of bone formation in ectopic transplantation systems in vivo. The use of mineralized scaffolds for guiding bone tissue engineering has revealed unexpected manners in which the scaffold and cells interact with each other, so that a complex interplay of integration and disintegration of the scaffold ultimately results in efficient and desirable, although unpredictable, effects. Likewise, the manner in which biomaterial scaffolds are "resorbed" by osteoclasts in vitro and in vivo highlights more complex scenarios than predicted from knowledge of physiological bone resorption per se. Investigation of novel biomaterials for bone engineering represents an essential area for the design of tissue engineering strategies.

Symmetric pollen mitosis I and suppression of pollen mitosis II prevent pollen development in Brachiaria jubata (Gramineae)

Microsporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata (BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains were prepared by squashing and staining with 0.5% propionic carmine. The meiotic process was typical of polyploids, with precocious chromosome migration to the poles and laggards in both meiosis I and II, resulting in tetrads with micronuclei in some microspores. After callose dissolution, microspores were released into the anther locule and appeared to be normal. Although each microspore initiated its differentiation into a pollen grain, in 11.1% of them nucleus polarization was not observed, i.e., pollen mitosis I was symmetric and the typical hemispherical cell plate was not detected. After a central cytokinesis, two equal-sized cells showing equal chromatin condensation and the same nuclear shape and size were formed. Generative cells and vegetative cells could not be distinguished. These cells did not undergo the second pollen mitosis and after completion of pollen wall synthesis each gave rise to a sterile and uninucleate pollen grain. The frequency of abnormal pollen mitosis varied among flowers and also among inflorescences. All plants were equally affected. The absence of fertile sperm cells in a considerable amount of pollen grains in this accession of B. jubata may compromise its use in breeding and could explain, at least in part, why seed production is low when compared with the amount of flowers per raceme.

Comorbidity of psychiatric disorders and symmetric distal polyneuropathy among type II diabetic outpatients

The objective of the present study was to establish the frequency of psychiatric comorbidity in a sample of diabetic patients with symmetric distal polyneuropathy (SDPN). Sixty-five patients with type 2 diabetes mellitus were selected consecutively to participate in the study at Instituto Estadual de Diabetes e Endocrinologia. All patients were submitted to a complete clinical and psychiatric evaluation, including the Portuguese version of the structured clinical interview for DSM-IV, the Beck Depression Inventory, the Neuropathy Symptom Score, and Neuropathy Disability Score. SDPN was identified in 22 subjects (33.8%). Patients with and without SDPN did not differ significantly regarding sociodemographic characteristics. However, a trend toward a worse glycemic control was found in patients with SDPN in comparison to patients without SDPN (HbA1c = 8.43 ± 1.97 vs 7.48 ± 1.95; P = 0.08). Patients with SDPN exhibited axis I psychiatric disorders significantly more often than those without SDPN (especially anxiety disorders, in general (81.8 vs 60.0%; P = 0.01), and major depression - current episode, in particular (18.2 vs 7.7%; P = 0.04)). The severity of the depressive symptoms correlated positively with the severity of SDPN symptoms (r = 0.38; P = 0.006), but not with the severity of SDPN signs (r = 0.07; P = 0.56). In conclusion, the presence of SDPN seems to be associated with a trend toward glycemic control. The diagnosis of SDPN in diabetic subjects seems also to be associated with relevant psychiatric comorbidity, including anxiety and current mood disorders.

QUANTITATIVE VS. CONVENTIONAL PCR FOR DETECTION OF HUMAN ADENOVIRUSES IN WATER AND SEDIMENT SAMPLES

SUMMARY Human Adenoviruses (HAdV) are notably resistant in the environment. These agents may serve as effective indicators of fecal contamination, and may act as causative agents of a number of different diseases in human beings. Conventional polymerase chain reaction (PCR) and, more recently, quantitative PCR (qPCR) are widely used for detection of viral agents in environmental matrices. In the present study PCR and SYBR(r)Green qPCR assays were compared for detection of HAdV in water (55) and sediments (20) samples of spring and artesian wells, ponds and streams, collected from dairy farms. By the quantitative methodology HAdV were detected in 87.3% of the water samples and 80% of the sediments, while by the conventional PCR 47.3% and 35% were detected in water samples and sediments, respectively.

Dot enzyme-linked immunosorbent assay (dot-ELISA) for schistosomiasis diagnosis using dacron as solid-phase

Dacron and nitrocellulose were evaluated as matrices for the dot enzyme linked immunosorbent assay (dot-ELISA) for schistosomiasis and compared to indirect immunofluorescence (IMF). Titration of sera from 18 schistosomiasis patients against soluble worm antigen preparation (SWAP) was carried out and sera from healthy individuals from non-endemic areas were used as controls. The IMF was less sensitive than the dot-ELISAs, although the difference was not statistically significant (p > 0.05). The dot-ELISA based on nitrocellulose was as sensitive as that using dacron. Stability did not differ between nitrocellulose and dacron. Specificity was lower when dacron was used than when nitrocellulose was used, although the difference was not statistically significant (p > 0.05). In conclusion, this work showed that nitrocellulose and dacron performed similarly in dot-ELISA, suggesting that they may be used alternatively in population surveillance in endemic areas.

Variación florística de especies arbóreas a escala local en un bosque de tierra firme en la Amazonia colombiana

El presente estudio se llevó a cabo en cinco hectáreas de una parcela permanente establecida en el Parque Nacional Amacayacu, Amazonia colombiana. En éste, se evaluó el efecto de la variación ambiental y la configuración espacial sobre los patrones florísticos de las especies arbóreas (DAP>10 cm) a escala local en un bosque de tierra firme. Se estudió la variación florística y ambiental en cuadrantes de 20x20 m. Adicionalmente, se consideraron diferentes categorías de abundancia (total, alta, media y baja). Se utilizó el Análisis de Correspondencia Linealizado y el Análisis de Correspondencia Canónica, seguido de una partición de la variación, para cuantificar la magnitud a la cual el ambiente y la limitación en dispersión determinan la variación florística. La fracción espacial, representando procesos de autocorrelación como la limitación en dispersión, se analizó mediante dos métodos: Asumiendo un polinomio de tercer grado y por el método de Coordenadas Principales de Matrices Vecinas (PCNM). La diversidad beta de la parcela fue baja. El PCNM aparece como el método de análisis más apropiado para estudios a esta escala. Las diferencias florísticas explicadas a lo largo de la parcela de 5-ha fueron principalmente asociadas con procesos biológicos como la limitación en dispersión. La mayor parte de la variación florística, no obstante, no fue explicada por las variables ambientales o espaciales consideradas. En conclusión, estos resultados sugieren que procesos aleatorios son determinantes esenciales de la variación espacial de las especies arbóreas a escala local en tierra firme en los bosques en el Parque Nacional Amacayacu.