Fabrication and Characterization of Native and Oxidized Potato Starch Biodegradable Films

The need to replace conventional polymers due to environmental pollution caused by them has led to increased production of biodegradable polymers such as starch. Thus, the application possibilities of starch have increased. In this study, we produced and characterized biodegradable films derived from native and oxidized potato starch. The film-forming solution was prepared with different concentrations of extracted starch (native or oxidized) and a plasticizer (glycerol or sorbitol). Then, the mechanical, barrier, morphological, and structural properties of the films were characterized. The moisture content of the films varied from 15.35?±?1.31 to 21.78?±?0.49%. The elastic modulus of the films ranged from 219?±?14.97 to 2299?±?62.91 MPa. The film of oxidized starch plasticized with sorbitol in the lowest content was the most resistant and flexible; moreover, this film also presented lower water vapor permeability and low solubility in water. Fourier-transform infrared spectroscopic analysis of the biodegradable films indicated the presence of same functional groups as those of starch with bands in the same regions. The film thickness was lower for the films plasticized with glycerol whereas the color variation (Δ?) was lower for the ones plasticized with sorbitol. In case of both plasticizers, the increase in their content decreased the Δ? value. All the biodegradable films presented stability against water absorption owing to their low solubility in water. Morphological evaluation revealed the presence of partially gelatinized starch granules in the films. The roughness parameter (Rq) of the films varied from 3.39 to 10.9 nm, indicating that their surfaces are smooth. X-ray diffraction studies showed a B-type pattern for the starches, which is representative of tubers. Further, the films present higher relative crystallinity (RC) compared to the starches. The biodegradable starch films are uniform, transparent and with low solubility in water. The oxidation of starch and use of sorbitol as a plasticizer resulted in improved properties of the starch films, which is suitable for application.     

Morphological study for understanding the sexual pattern in ghost shrimp Callichirus major (Crustacea: Axiidea)

Callichirus major is a species of ghost shrimp that has burrowing habits, building underground galleries in the intertidal region of beaches. This study aimed to analyse some morphological parameters to verify its type of sexual pattern. A sample of 79 individuals, collected at the beach of Corujão, Espírito Santo, Brazil, was used. Data on the external morphology, presence of gonopores, carapace length (CL) and cheliped lengths (Lch) were obtained. In addition, the gonads were processed for histological analysis. The animals were divided into three categories: A, individuals with male characteristics; B, those presenting exclusively female characteristics; C, animals with characteristics of intersex, which presented supernumerary gonopores. Positive allometries were found for Lch versus CL only for category A, characterizing the group's marked heterochely. Histologically, it was possible to observe the presence of oocytes in category A and one case of male tissue in an intersex individual (category C). However, no genital ducts of both sexes were found in that individual. Callichirus major presents controversial sexual characters, which makes it difficult to understand the reproductive parameters and sexual pattern. However, maybe that species can develop a sexual system of hermaphroditism.     

Changing Mortality Profile among HIV-Infected Patients in Rio de Janeiro,Brazil: Shifting from AIDS to Non-AIDS Related Conditions in the HAART Era

Introduction

We describe temporal trends in the mortality rates and factors associated with AIDS and non-AIDS related mortality at the Evandro Chagas Clinical Research Institute (IPEC), Oswaldo Cruz Foundation (FIOCRUZ).

Methods

Adult patients enrolling from 1986 through 2009 with a minimum follow up of 60 days were included. Vital status was exhaustively checked using patients’ medical charts, through active contact with individuals and family members and by linkage with the Rio de Janeiro Mortality database using a previously validated algorithm. The CoDe protocol was used to establish the cause of death. Extended Cox proportional hazards models were used for multivariate modeling.

Results

A total of 3530 individuals met the inclusion criteria, out of which 868 (24.6%) deceased; median follow up per patient was 3.9 years (interquartile range 1.7–9.2 years). The dramatic decrease in the overall mortality rates was driven by AIDS-related causes that decreased from 9.19 deaths/100PYs n 1986–1991 to 1.35/100PYs in 2007–2009. Non-AIDS related mortality rates remained stable overtime, at around 1 death/100PYs. Immunodeficiency significantly increased the hazard of both AIDS-related and non-AIDS-related causes of death, while HAART use was strongly associated with a lower hazard of death from either cause.

Conclusions

Our results confirm the remarkable decrease in AIDS-related mortality as the HIV epidemic evolved and alerts to the conditions not traditionally related to HIV/AIDS which are now becoming more frequent, needing careful monitoring.     

Cell surface hydrophobicity and slime production of Staphylococcus epidermidis Brazilian isolates

The cell surface hydrophobicity of 60 isolates and three reference strains of Staphylococcus epidermidis was assayed by means of bacterial aggregation in liquid broth, phosphate-buffered saline, and in ammonium sulfate, as well as by affinity of the bacteria to n-hexadecane and polystyrene surfaces. In order to better characterize the isolates, the influence of bacterial growth time and enzyme treatment on cell hydrophobicity and the analysis of the slime production were also investigated. The strains presented the following profiles when assayed by the ammonium sulfate aggregation test (SAT): SAT < 1M, SAT 1M - <2M, SAT 2M - <4M, and SAT >or=4M. When SAT < 1M, the strains showed positive results for most of the cell surface hydrophobicity tests. None of the strains belonging to the groups with SAT >or= 1M showed spontaneous aggregation (SA), auto-aggregation (AA), or glass adherence, albeit 32 (62.7%) strains were polystyrene adherent and 42 (82.3%) presented weak adherence to n-hexadecane (>20%). The best correlation of the results was found among the AA and glass adherence tests (100%), followed by SA/ glass adherence (98%) and SA/ AA test (98%). The polystyrene adherence test and microbial adherence to n-hexadecane test (MATH) showed 78% correlation. Proteinase K treatment reduced bacterial adherence to polystyrene, but did not influence the SAT values. Three distinct groups of strains were distinguished by the polystyrene micromethod and glass tube adherence assay: 0.0-0.4 O.D. group, including non-glass adherent isolates; 0.5-0.7 O.D. group, including strains with variable profiles (adherent or non-adherent); and 0.8-1.3 O.D. group, composed of glass-adherent strains. Evaluation by a single method seemed not to reliably determine the surface hydrophobicity characteristics of S. epidermidis clinical isolates. Auto-aggregation properties of the strains that adhered to glass seemed related to slime expression, rather than cell surface hydrophobicity. Data also suggested involvement of protein components in adherence to polystyrene, but not in auto-aggregation properties assayed by SAT.     

Biofouling control using microparticles carrying a biocide

This study presents a new technological approach to minimize the use of antimicrobial (AMB) agents and their deleterious effects, based on the principle of drug-delivery systems whereby the AMB chemicals are transported on microparticles. The efficacy of microparticles carrying the quaternary ammonium compound (QAC), benzyldimethyldodecyl ammonium chloride (BDMDAC), was assessed against Pseudomonas fluorescens in both the planktonic and the biofilm state. The microparticles were prepared using a layer-by-layer (LBL) self-assembly technique. Oppositely charged molecules of polyethyleneimine (PEI), sodium polystyrene sulfonate (PSS), and BDMDAC were assembled on polystyrene (PS) cores. BDMDAC-coated particles were observed by CryoSEM and their composition analyzed by X-ray microanalysis. Zeta potential measurements indicated that changes in surface charge were compatible with a BDMDAC/particle interaction. This biocidal carrier structure had significant stability, verified by the release of only 15% of the BDMDAC when immersed in water for 18 months. Biocidal carrier activity was evaluated by determining the survival ratio of P. fluorescens planktonic and biofilm cells after different exposure periods to BDMDAC-coated particles. Tests with biofilm cells were also performed with the free QAC. An efficient AMB effect (minimum bactericidal concentration) against suspended cells was found for a concentration of 9.2 mg l^?1 of BDMDAC on coated particles after incubation for 30 min and 6.5 mg l^?1 of BDMDAC on coated particles after 60 min. Exposure of biofilms to PS-PEI/PSS/BDMDAC (0.87 mg l^?1) resulted in a decrease in viability of 60.5% and 66.5% of the total biofilm population for 30 and 60 min exposure times, respectively. Exposure for 60 min to 6.33 mg l^?1 and 11.75 mg l^?1 of BDMDAC in PS-PEI/PSS/BDMDAC particles promoted inactivation of 80.6% and 87.2% of the total population, respectively. The AMB effects obtained with the application of free BDMDAC were statistically similar to those promoted by the application of BDMDAC coated particles. The overall results indicate that this novel AMB strategy has potential for the control of microbial growth of planktonic cells and biofouling. Moreover, the technique allows the reuse of AMB molecules and consequently reduces the environmental risks associated with excessive use of AMB agents, thereby providing real benefits to public health.     

Homogeneously sized groups increase aggressive interaction and affect social stress in Thai strain Nile tilapia (Oreochromis niloticus)

Social fish raised in farms are usually kept in groups of similar-sized individuals. However, social animals of similar size typically have similar fighting ability, which increases aggressive interaction for social rank establishment, as well as social stress. We compared Thai strain Nile tilapia fish, Oreochromis niloticus (L.), held under two treatments: (1) The Homogeneous one, with five adult male fish of similar size and (2) the Heterogeneous treatment with five adult males of different sizes. We recorded the frequency of aggressive interactions and checked social stability and stress levels (cortisol) after five days in the groups. Grouping similar sized Thai Nile tilapia increased the aggressive interactions and delayed rank stability with increased body injuries as a consequence. Homogeneous-sized individuals showed a similar level of stress while heterogeneous-sized individuals showed different stress levels with dominants being more stressed than subordinates. The data indicate that the practice of selecting fish of similar size in aquaculture management could reduce the welfare of social fish and that the effect is observed in different lineages.     

Effect of Phase Shift from Corals to Zoantharia on Reef Fish Assemblages

Consequences of reef phase shifts on fish communities remain poorly understood. Studies on the causes, effects and consequences of phase shifts on reef fish communities have only been considered for coral-to-macroalgae shifts. Therefore, there is a large information gap regarding the consequences of novel phase shifts and how these kinds of phase shifts impact on fish assemblages. This study aimed to compare the fish assemblages on reefs under normal conditions (relatively high cover of corals) to those which have shifted to a dominance of the zoantharian Palythoa cf. variabilis on coral reefs in Todos os Santos Bay (TSB), Brazilian eastern coast. We examined eight reefs, where we estimated cover of corals and P. cf. variabilis and coral reef fish richness, abundance and body size. Fish richness differed significantly between normal reefs (48 species) and phase-shift reefs (38 species), a 20% reduction in species. However there was no difference in fish abundance between normal and phase shift reefs. One fish species, Chaetodon striatus, was significantly less abundant on normal reefs. The differences in fish assemblages between different reef phases was due to differences in trophic groups of fish; on normal reefs carnivorous fishes were more abundant, while on phase shift reefs mobile invertivores dominated.     

A pharmacological comparison of [3H]GBR12935 binding to rodent striatal and kidney homogenates: binding to dopamine transporters?

Binding of [3H]GBR12935 to homogenates of mouse and rat striatum and kidney was studied. [3H]GBR12935 bound to both tissue preparations with high affinity (mouse striatum Kd = 2.4 +/- 0.4 nM, n = 4; mouse kidney Kd = 3.8 +/- 0.9 nM, n = 4), in a saturable (striatal Bmax = 1.5 +/- 0.4 pmol/mg protein; kidney Bmax = 4.9 +/- 0.5 pmol/mg protein) and reversible manner. Saturation experiments revealed the presence of a single class of high affinity binding sites in both tissues of both species. Mouse kidney appeared to possess a greater density of [3H]GBR12935 binding sites than the striatum while the reverse situation prevailed for the rat. Although two dopamine uptake inhibitors, namely GBR12909 and benztropine, displaced [3H]GBR12935 binding from striatal and kidney homogenates with a similar affinity in both tissues of these species, unlabelled mazindol, (+/-)cocaine, nomifensine and amfonelic acid were significantly (P < 0.001-0.02) more potent inhibitors of [3H]GBR12935 binding in the striatum than in the kidney. While the pharmacological profile of [3H]GBR12935 binding in the rodent striatum compared well with that of the dopamine transporter reported previously, the pharmacology in the kidney was considerably different to that in the striatum. GBR12909 (1-30 mg/kg, i.p.), a close analog of GBR12935, induced significant antidiuretic and antinatriuretic effects in spontaneously hypertensive rats. These data suggest that while [3H]GBR12935 labels the dopamine uptake sites in the brain, it does not appear to label similar sites in the kidney. The mechanism of action of GBR12909 on sodium and water excretion remains to be determined.