Influence of the Processing Parameters on the Characteristics of Spherical Bacterial Cellulose     

Ricardo Brandes  Letícia de Souza  Daniel V. F. Vanin  Claudimir A. Carminatti  Eliana M. Oliveira  Regina V. Antônio  Derce O. S. Recouvreux 《Fibers and Polymers》2018,19(2):297-306

Bacterial Cellulose (BC) biosynthesized under agitated conditions can produce hydrogels with spherical shapes and the processing parameters govern this formation of BC hydrogels. The variations of these parameters cause different results in the formation of spherical BC and it is relevant to evaluate these effects. Carbon source, inoculum concentration, volume of the culture medium, stirring speed and incubation temperature were the processing parameters evaluated in this work. Therefore, the results obtained were characterized in terms of dry mass production, water uptake and sphericity of the spherical BC. To do so, Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were employed as tools for morphological and chemical evaluations. Among the parameters analyzed, the carbon source had the greatest effect on the production of dry mass and water uptake. Glycerol had the greatest growing rate, generating a higher dry mass production with spherical and homogeneous bodies with excellent water absorption indexes. Furthermore, the morphological analysis of BC revealed a typical structure, with high crystallinity index and the presence of typical functional groups. These results indicate a path for the optimized and controlled production of spherical BC, allowing it to be used in many applications, such as enzyme immobilization, water treatment, bone regeneration, spherical cancer model, as adsorption agent and drug delivery.  相似文献   

Genetic basis of Spodoptera frugiperda (Lepidoptera: Noctuidae) resistance to the chitin synthesis inhibitor lufenuron          下载免费PDF全文

Antonio Rogério Bezerra do Nascimento  Juliano Ricardo Farias  Daniel Bernardi  Renato Jun Horikoshi  Celso Omoto 《Pest management science》2016,72(4):810-815

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Intraguild predation of Geocoris punctipes on Eretmocerus eremicus and its influence on the control of the whitefly Trialeurodes vaporariorum          下载免费PDF全文

Lourdes Bao‐Fundora  Ricardo Ramirez‐Romero  Carla V Sánchez‐Hernández  José Sánchez‐Martínez  Nicolas Desneux 《Pest management science》2016,72(6):1110-1116

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Water Quality and Chlorophyll Measurement Through Vegetation Indices Generated from Orbital and Suborbital Images     

Anny Keli Aparecida Alves Cândido  Antonio Conceição Paranhos Filho  Marcelo Ricardo Haupenthal  Normandes Matos da Silva  Jonas de Sousa Correa  Maria Lucia Ribeiro 《Water, air, and soil pollution》2016,227(7):224

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Interaction of Rotylenchulus reniformis and Meloidogyne javanica with mealybug wilt of pineapple,in microplots     

Thiago de Freitas Ferreira  Ricardo Moreira Souza  Karla Daiana dos Santos Ferreira  Welington Sérgio Silva Idalino 《European journal of plant pathology / European Foundation for Plant Pathology》2015,141(4):761-768

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Production of Hyaluronic Acid by Streptococcus zooepidemicus on Protein Substrates Obtained from Scyliorhinus canicula Discards     

José A. Vázquez  Lorenzo Pastrana  Carmen Pi?eiro  José A. Teixeira  Ricardo I. Pérez-Martín  Isabel R. Amado 《Marine drugs》2015,13(10):6537-6549

This work investigates the production of hyaluronic acid (H) by Streptococcus equi subsp. zooepidemicus in complex media formulated with peptones obtained from Scyliorhinus canicula viscera by-products. Initially, in batch cultures, the greatest productions were achieved using commercial media (3.03 g/L) followed by peptones from alcalase hydrolyzed viscera (2.32 g/L) and peptones from non-hydrolyzed viscera (2.26 g/L). An increase of between 12% and 15% was found in subsequent fed-batch cultures performed on waste peptones. Such organic nitrogen sources were shown to be an excellent low-cost substrate for microbial H, saving more than 50% of the nutrient costs.  相似文献   

Leucocyte profile and growth rates as indicators of crowding stress in pejerrey fingerlings (Odontesthes bonariensis)          下载免费PDF全文

Yuri Dornelles Zebral  Bruna Zafalon‐Silva  Mabel Wiegand Mascarenhas  Ricardo Berteaux Robaldo 《Aquaculture Research》2015,46(9):2270-2276

Crowding is one of the most common stressors found in intensive aquaculture, compromising growth rates and immune function. Plasmatic cortisol is a classic stress biomarker for fish, but its quantification is expensive and demands blood volumes that small individuals do not provide, constraining the usage of this technique to assess stress in fingerlings. The leucocyte profile is an alternative methodology to quantify stress with reduced costs and volumes of blood. Stress conditions promote neutrophilia and lymphocytopenia as response to elevated glucocorticoids levels. Considering the difficulties to assess stress imposed by intensive fish farming using measurement of glucocorticoid hormones, this study aimed to evaluate the stress‐induced changes in leucocyte profiles and growth rates imposed by crowding in fingerlings of Odontesthes bonariensis, a promising South‐American candidate for freshwater aquaculture. To meet these objectives, fingerlings (initial weight 0.05 ± 0.06 g and length 1.68 ± 0.13 cm) were reared for 45 days under three rearing densities (1, 5 and 10 fingerlings L^?1). At the end of this period, fish were anaesthetized and euthanized to obtain the leucocyte profile, neutrophil:lymphocyte ratio (N:L) and growth rate. Increasing density promoted: significant reduction in growth (final length, weight and specific growth rate); neutrophilia and lymphocytopenia; and increased N:L ratio. Concluding, the tested rearing densities imposed distinct levels of stress characterized by different N:L ratio, demonstrating that the leucocyte profile is a reliable alternative to measure stress levels in O. bonariensis fingerlings and probably in other fish species.  相似文献   

Acute tolerance and histopathological effects of ammonia on juvenile maroon clownfish Premnas biaculeatus (Block 1790)     

Ricardo Vieira Rodrigues  Luis Alberto Romano  Michael Hans Schwarz  Brendan Delbos  Luís André Sampaio 《Aquaculture Research》2014,45(7):1133-1139

This study evaluated the median lethal concentration values (LC₅₀) and the histopathological effects of un‐ionized ammonia (NH₃^‐‐N) on juvenile maroon clownfish Premnas biaculeatus. After 96 h of exposure to different concentrations of ammonia, juveniles were sampled for histopathological evaluation. The 24 and 96 h LC50 values of NH₃^?‐N determined were 1.68 and 0.89 mg L^?1 respectively. Maroon clownfish exposed to different ammonia concentrations displayed histopathological alterations in the gills, kidney, liver and brain. Gill tissue damage included lamellar hyperplasia, lamellar shorting and hyperplasia and hypertrophy of mucous cells. The kidney showed hyperanaemia, enlarged sinusoids within an apparently decreased amount of haematopoietic tissue, oedema on tubular cells and tubular necrosis, and an enlarged Bowman's capsule. The liver presented dilatation of hepatic sinusoids, fatty deposition in hepatocytes and Mallory bodies. Examination of the brain revealed a proliferation of glial cells, and the Virchow‐Robin space indicated a severe perivascular oedema and signs of neuronal suffering with satellitosis. The results of this study indicate that juvenile maroon clownfish are relatively sensitive to ammonia and particular attention must be given to this toxic compound in culture systems.  相似文献   

Pancytopenia in a cat with visceral leishmaniasis     

Ricardo Marcos  Marta Santos  Fernanda Malhão  Rui Pereira  Ana Cristina Fernandes  Luís Montenegro  Paola Roccabianca 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2009,38(2):201-205

Abstract: A 4‐year‐old, domestic shorthair, female spayed cat was presented for decreased appetite and depression. Severe pancytopenia with erythrocyte autoagglutination was found. The cat was seronegative for feline immunodeficiency and leukemia viruses. Immune‐mediated hemolytic anemia was suspected but no response to treatment with a blood transfusion, enrofloxacin, and prednisone was observed. Blood and bone marrow smears obtained 11 days later contained Leishmania amastigotes in the cytoplasm of neutrophils and macrophages, respectively. Serologic and PCR testing of peripheral blood confirmed infection with Leishmania infantum. Despite treatment, the cat worsened clinically and was euthanized. At necropsy, visceral dissemination of the parasite was confirmed. The findings in this case indicate that visceral leishmaniasis should be considered as a differential diagnoses in cats with pancytopenia in areas endemic for Leishmania. In addition, amastigotes may be observed in peripheral blood neutrophils.  相似文献   

Impact of mole drains on salinity of a vertisoil under irrigation     

Paulo J.N. Castanheira  Ricardo P. Serralheiro 《Biosystems Engineering》2010,105(1):25-33

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