Scielo RSS <![CDATA[Brazilian Archives of Biology and Technology]]> vol. 58 num. 1 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Purification of C-phycocyanin from Spirulina platensis in aqueous two-phase systems using an experimental design]]> C-phycocyanin from Spirulina platensis was purified in aqueous two-phase systems (ATPS) of polyethylene glycol (PEG)/potassium phosphate, varying the molar mass of the PEG. Results using a full factorial design showed that an increase in the concentration of salt and decrease in the concentration of PEG caused an increment in the purification factor for all the ATPS studied. Optimization of the conditions of the purification was studied using a central composite rotatable design for each molar mass of PEG. The ATPS composed of 7% (w/w) PEG 1500 or 4% (w/w) PEG 8000 (g/gmol) and 23 or 22.5% (w/w) of phosphate resulted a purification factor of 1.6-fold for C-phycocyanin, with total and 57% recovery, respectively. Process conditions were optimized for the purification factor for the system with PEG 1500. The ATPS with 4% (w/w) PEG 4000 or 4% (w/w) PEG 6000 and 21% (w/w) phosphate resulted purification factors of 2.1 and 2.2-fold, recovering 100% and 73.5%, respectively of C-phycocyanin in the top phase. <![CDATA[Seasonal influence on the essential oil production of Nectandra megapotamica (Spreng.) Mez]]> This study evaluated the seasonal influence on the yield and chemical composition of the essential oil (EO) of Nectandra megapotamica. Fresh young (YL) and old leaves (OL) obtained from three trees in each season (Nov/2010 to Sep/2011) collected in Santa Maria-RS were hydrodistilled in triplicate. The chemical composition was determined by the gas chromatography coupled to mass spectrometry (GC-MS) and the yield on dry basis was evaluated by two-way ANOVA (seasons, development stage). Spring (Sp) and summer (Su) showed higher average incomes (0.45 and 0.33%), which occurred when flowering, fruiting, and growth of YL and senescence of OL took place, while autumn (Au) presented the lowest yield (0.25%) during the rustification of OL. The highest yield was obtained for the YL in Sp (0.59%) and the lowest for the OL in Au (0.21%). The major constituents of the EO were independent from the season and were identified as α-pinene, bicyclogermacrene, β-pinene, germacrene D, and limonene. Seasonality and phenology influenced the production of EO probably due to morphological and metabolic alterations in the leaves as well as due to the needs of the tree, such as attraction and/or protection. <![CDATA[Slow-release urea in supplement fed to beef steers]]> Replacing regular urea (RU) by slow-release urea (SRU) at two levels of non-protein nitrogen (NPN) in concentrate, offered with low-quality roughage, was evaluated in beef steers on dry matter intake (DMI), ruminal fermentation parameters, plasma urea nitrogen (PUN), total tract apparent digestibility of diets and in situ degradability of nitrogen sources. Eight ruminally cannulated steers were allocated into two 4x4 Latin squares, totalizing four treatments: 40 NPN/0 SRU: 40% of concentrate crude protein (CP) as NPN, resulting from 0% of SRU and 100% of RU; 40 NPN/50 SRU: 40% of concentrate CP as NPN, resulting from 50% of SRU and 50% of RU; 40 NPN/100 SRU: 40% of concentrate CP as NPN, resulting from 100% of SRU and 0% of RU; 80 NPN/100 SRU: 80% of concentrate CP as NPN, resulting from 100% of SRU and 0% of RU. Results showed that partial substitution of regular urea by slow-release urea did not alter dry matter intake, pattern of ruminal fermentation or plasma urea nitrogen concentrations and increased the total tract apparent digestibility of crude protein in steers diets. The increase in non-protein nitrogen content in crude protein of the concentrate could compromise feed intake and the efficiency of nutrient utilization in the steers fed complete diets based on low quality forage. <![CDATA[Triplaris americana L. (Polygonaceae), a New Host Plant For Aethalion reticulatum (Linnaeus, 1767) (Hemiptera: Aethalionidae)]]> Triplaris americana is a plant that has been applied as ornamental specie and also as natural medicine. Adults and immature stages of Aethalion reticulatum were observed colonizing specimens of this plant in Sinop, MT, Brazil, which represent the first record of this leafhopper colonizing this specie. <![CDATA[Use of Different Kinds of Solutes Alternative to Sucrose in Osmotic Dehydration of Yacon]]> The present work aimed to evaluate glycerol, maltodextrin, polydextrose and sorbitol for the osmotic dehydration of yacon for diabetics, keeping its properties as prebiotic. Osmotic dehydration was carried out using a yacon to 33% concentrated syrup weight ratio of 1:12, with magnetic stirring at 23ºC and atmospheric pressure. The best results were achieved for glycerol and sorbitol with 80 ± 4% and 81± 1% of water removal and increase of 3.73 ± 0.11 and 4.30 ± 0.16 times in total soluble solids respectively. Maltodextrin did not promote dehydration. <![CDATA[Antidepressant effects of standardized extract of Commiphora mukul Engl. in olfactory bulbectomized rats]]> The objective of this work was to evaluate the effects of standardized hydroalcholic extract of Commiphora mukul (HECM) in animal model of chronic stress medicated depression, namely olfactory bulbectomy (OBX) model in rats. Effects of 14-day (subacute) oral pretreatment of HECM (50, 100 and 200 mg/kg) were evaluated on depression and stress related parameters on OBX rats. Separate groups for sham control, OBX control and positive controls namely imipramine (20 mg/kg), fluoxetine (30 mg/kg) and desipramine (15 mg/kg) were also maintained. Behavioral and physiological parameters in open field and elevated plus maze were recorded. HECM showed dose-dependent reversal of OBX-induced physiological effects such as reduction of body weight, body temperature, heart rate and serum sodium concentration. HECM also showed reversal effects on OBX induced food intake increase and hyperactivity in open field and elevated plus maze paradigm. In conclusion, HECM demonstrated restorative effects in OBX induced depression model in rats probably due to stress reliving mechanisms. <![CDATA[Atraumatic restorative treatment - glass ionomer sealants survival after a postgraduate training program in Ecuador: 2-year follow-up]]> This study aimed to evaluate the survival of atraumatic restorative treatment high-viscosity glass ionomer sealants (ART-hvGIS) and its relationship with carious lesions incidence in underserved communities of Ecuador. A total of 483 first permanent molars with ART-hvGIS were included after treatment, in which fifteen students of the First Preventive Dentistry Post Graduate Program of Universidad Central del Ecuador assisted 176 schoolchildren, from 5 to 12 year-old. All the students had previously participated in a training course in ART approach. After one and two years follow-up, schoolchildren were reevaluated in relation to sealants retention and new carious lesions development. After first year of evaluation ART-hvGIS retention rate was about 30% and after second year 20%. Incidence of carious lesions was 4.0 and 3.4% after first and second periods, respectively. Although there was an extensive ART-hvGIS loss, carious lesions incidence was low in both the periods of evaluation. ART-hvGIS might be an important key to prevent tooth decay in underserved communities. <![CDATA[Detection of Streptococcus mutans using padlock probe based on Rolling Circle Amplification (RCA)]]> The aim of this study was to develop and evaluate a padlock probe based on the Rolling Circle Amplification (RCA), which targeted to 16S-23S rDNA region of S. mutans. The specificity of developed padlock probe was tested for DNA within a panel strains, including S. mutans isolated from the saliva and reference strains of the genus Streptococcus, as well as total DNA samples of biofilm and saliva. The results were positive either for DNA samples of S. mutans or DNA samples recovered from the biofilm and saliva revealing the specificity of designed padlock probe. The padlock probe based on the RCA was proved to be an effective, reproducible method for S. mutans detection and demonstrated the possibility of a rapid detection and accurate identification of S. mutans infection. <![CDATA[In vitro cytotoxic, genotoxic and antioxidant/oxidant effects of guaiazulene on human lymphocytes]]> The aim of this study was to evaluate for the cytotoxicity, genotoxicity and antioxidant/oxidant activity of GYZ on human peripheral blood lymphocytes (PBLs). Guaiazulene (GYZ) was added into culture tubes at various concentrations (0-400 µg/mL-1). Cytotoxicity against the human lymphocytes cultures was examined by lactate dehydrogenase (LDH) release assay. The proliferative response was estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Antioxidant/oxidant activity was evaluated by measuring the total oxidant status (TOS) and total antioxidant capacity (TAC) levels. Micronucleus (MN) and chromosomal aberration (CA) tests were used in genotoxicity studies. The results showed that GYZ caused cytotoxicity in the PBLs at high concentrations, but TOS level were not affected, while the level of TAC was significantly increased. GYZ also did not induce chromosomal aberrations when compared to that of the control group. Results this study clearly revealed that GYZ was not genotoxic and also increased the capacity of the antioxidant in the culture of human PBL cells. This report is first report on the impact of GYZ on human PBL cells. <![CDATA[Lead Nitrate Induced Testicular Toxicity in Diabetic and Non-Diabetic Rats: Protective Role of Sodium Selenite]]> Among heavy met als, lead is one of the common pollutants found in the environment and biological system. In the present study, streptozotocin-induced diabetic and normal non-diabetic male Wistar rats were given sodium selenite (1.0 mg/kg bw), lead nitrate (22.5 mg/kg bw) and sodium selenite plus lead nitrate (1.0 mg/kg+22.5 mg/kg bw, respectively) through gavage. At the end of 4th week, malondialdehyde (MDA) levels, antioxidant enzyme activities [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST)], and histopathological changes of testes were investigated compared to the control group. No significant differences were observed between the control and sodium selenite treated groups. However, lead nitrate increased the levels of MDA, SOD, CAT, GPx and GST activities compared with the control group in diabetic and non-diabetic rats. Light microscopic analyses revealed that lead nitrate induced numerous histopathological changes in testis tissues of diabetic and non-diabetic rats. In the diabetic and non-diabetic sodium selenite plus lead nitrate treated groups, there were statistically significantly decreased MDA levels and antioxidant enzymes activities and mild pathological changes. As a result, sodium selenite significantly reduced lead nitrate induced testicular toxicity for both diabetic and non-diabetic rats. <![CDATA[The investigation of cytogenetic and oxidative effects of diffractaic acid on human lymphocyte cultures]]> Diffractaic acid (DA) is a naturally occurring depside derivative found in several lichen species. It has a wide range of important biological effects such as analgesic and antiviral properties, although its cytotoxic, cytogenetic and oxidative effects have not been investigated in human blood tissue yet. Therefore, increasing concentrations (1, 5, 10, 25, 50, 100 and 200 mgL-1) of DA was added into human whole blood cultures. 3-(4.5-dimethylthiazol-2-yl)-2.5-diphenyl tetrazolium bromide (MTT) assay was used to assess the cell viability and/or cytotoxicity and genotoxic damage potential of DA using chromosome aberration (CA) and micronucleus (MN) tests were performed. In addition, oxidative alterations were determined by the total antioxidant capacity (TAC) and total oxidant status (TOS) assays. The results revealed that DA reduced cell viability at higher concentrations than 50 mgL-1. The all tested concentrations of DA were non-genotoxic. In vitro treatments with DA led to increases of TAC levels in the cultured blood cells without changing the TOS levels as compared to the control group. Consequently, DA exhibited a significant non-mutagenic and antioxidant potential in vitro. <![CDATA[Age-related Changes in DNA Methylation Status of hTERT Gene Promoter of Oral Epithelial Cells]]> The purpose of this study was to investigate the effect of aging on the DNA methylation status of two genes involved in tumorigenesis (telomerase gene hTERT and DNA repair gene- MLH1) and one in metabolism (methylenetetrahydrofolate reductase gene- MTHFR) in oral epithelial cells. DNA methylation analysis was performed by Methylation Sensitive Restriction Enzymes (MSRE) of healthy oral epithelial cells of child (6-10 years, n=21), young (20-25 years, n=19) and elderly (over 60 years, n=25). The results for the hTERT gene showed significant variation in the methylation frequency at CpG dinucleotides among the groups (p=0.0001), with the methylated condition more frequently in children and young people. In relation to MLH1 and MTHFR, no differences were observed among the groups and the unmethylated condition were present in most individuals (p&gt;0.05). Thus, it was concluded that aging of oral epithelial cells was associated with hypomethylation of the hTERT gene promoter and this could be a promising marker for screening a set of age-related alterations. <![CDATA[Cloning and Functional Assessment of the Recombinant Human Hepcidin-25 in the Baculovirus Expression System]]> Hepcidin is the primary regulatory hormone responsible for lowering the iron content in the blood circulation. Due to its biodegradability and low cytotoxicity, hepcidin is considered as an alternative for iron chelators. The baculovirus expression system may be suitable for human hepcidin production because the expressed proteins generally exhibit proper folding, post-translational modifications, and oligomerization. Using data from two vector maps, pFastBac1 and pFastBac HTB, a unique vector was designed encoding human hepcidin-25 as fusion recombinant peptide. Expression analysis showed that it was expressed as a peptide with a molecular weight near to 5 kDa. After purification and TEV treatment, findings revealed that recombinant human hepcidin-25 was functional and its effect was dose dependent (P=0.001). It was concluded that baculovirus expression was a suitable expression system for production of functional recombinant human hepcidin-25. <![CDATA[Extraction of Indigo from Some Isatis species and Dyeing Standardization Using Low-technology Methods]]> Fresh leaves of four Isatis species culture form of I. tinctoria L and wild forms of I. buschiana Schischkin, I. candolleana Boiss. (endemic) and I. tinctoria L. subsp. corymbosa. (Boiss.) were used for indigo production. Dyes were extracted by fermentation and hot water application. The extracted dyes were optimized with different pH and reducing agents. Results showed that the dye from hot water application produced the desired dying quality at pH 11. Reducing agent concentrations had no significant effect on color quality. Dark blue and blue colors were obtained from I. tinctoria and I. candolleana extracts although I. tinctoria subsp. corymbosa and I. buschiana produced mostly yellow-gray colors. Light, dry and wet rubbing fastness values varied between 3 and 3/4 while washing fastness was between 2 and 4/5. The highest indigo amounts were determined spectrophotometrically as 4.19 mg/g and 2.53 mg/g in I. tinctoria and I. candolleana, respectively. Results also showed that harvesting season was important for indigo production and the highest indigo amount was observed in mid-June. <![CDATA[Grazing Scar Characteristics Impact Degree of Fungal Facilitation in Spartina alterniflora Leaves in a South American Salt Marsh]]> Grazing scars of burrowing crabs and Hemiptera insects were simulated on leaves of the salt marsh grass Spartina alterniflora. Simulations of crab feeding generated two-fold higher fungal (ergosterol) content in leaves in comparison to that generated by insect scar simulations (1.26 ±0.55 and 0.57 ±0.25 µg per cm², respectively). This study provided evidence that herbivory could facilitate microbial infection by fungi in dominant South American salt marsh plants and indicated that specific feeding mechanisms used by different herbivores might differentially impact the strength of this interaction. <![CDATA[Soft Collagen-Gelatine Sponges by Convection Drying]]> This study showed that thermally labile fibrillar collagen could be processed continuously in combination with gelatine as foaming additive by convection drying. The procedure led to stable sponges with similar structural and physical properties as found for freeze-dried collagen samples. The fibrillar collagen remained native, while gelatine acted as foaming additive. The absorbency of the sponges was improved by opening the surface with abrasives. A use as medical device with hemostyptic properties would be possible. <![CDATA[Physiological Changes in the Seeds of Jatropha curcas L. at Different Stages of Fruit Maturity]]> The objective of present study was to determine appropriate fruit harvesting stage for Jatropha curcas L. for getting seeds with good oil content and better germination. The seeds separated from the fruits harvested at yellow capsule stage (C2) showed maximum germination efficiency, both under laboratory and nursery conditions whereas seeds separated from the fruits harvested at brownish black stage (C3) yielded highest oil content. Yellow capsule stage (C2) was physiologically mature fruit stage, which should be harvested to obtain the seeds with higher oil content besides showing maximum germination efficiency. <![CDATA[Immobilized Biofilm in Thermophilic Biohydrogen Production using Synthetic versus Biological Materials]]> Biohydrogen production was studied from the vermicelli processing wastewater using synthetic and biological materials as immobilizing substrate employing a mixed culture in a batch reactor operated at the initial pH 6.0 and thermophilic condition (55 ± 1ºC). Maximum cumulative hydrogen production (1,210 mL H2/L wastewater) was observed at 5% (v/v) addition of ring-shaped synthetic material, which was the ring-shaped hydrophobic acrylic. Regarding 5% (v/v) addition of synthetic and biological materials, the maximum cumulative hydrogen production using immobilizing synthetic material of ball-shaped hydrophobic polyethylene (HBPE) (1,256.5 mL H2/L wastewater) was a two-fold increase of cumulative hydrogen production when compared to its production using immobilizing biological material of rope-shaped hydrophilic ramie (609.8 mL H2/L wastewater). SEM observation of immobilized biofilm on a ball-shaped HBPE or a rope-shaped hydrophilic ramie was the rod shape and gathered into group. <![CDATA[Hepatic Cytochrome P450 as Biomarkers of Cypermethrin Toxicity in Freshwater Teleost, Channa punctatus (Bloch)]]> In this study, Channa punctatus was treated with sub-lethal concentration of cypermethrin (6.6 µg/L) for 5, 10 and 15 days and its effect on total CYP 450 and the activity of hepatic CYP450 isoforms measured. Total CYP450 content and CYP1A mediated EROD activity was significantly induced (p&lt;0.05) in all three treated groups compared to control whereas only 15 days treated group showed significant induction in CYP2B mediated N,Ndimethylaniline demethylase activity. CYP2E1 mediated aniline hydroxylase activity showed only a marginal increase while there was inhibition of CYP3A4 mediated erythromycin demethylase activity. Liver somatic index (LSI) also showed a marginal increase in all the treated groups. Results showed differential induction of CYP1A, CYP2B, CYP2E1 and inhibition of CYP3A4 isoform due to cypermethrin treatment in C. punctatus. The study clearly showed CYP1A isoform as the most responsive and important biomarker for monitoring the aquatic pollution. <![CDATA[Microbial Diversity: Relevance and Relationship Between Environmental Conservation And Human Health]]> This work presents bibliographic data on the role and function of microbial diversity. The increasing use of probiotics and prebiotics foods has led to the studies on their actual functions in the human body. It is known that in the environment, microorganisms are extremely important in recycling of nutrients, balance of trophic chains, vital physiological activities in the plants and animals, as well as the conservation of natural habitats. In human food, these microscopic organisms contribute from flavoring products to the synthesis of antimicrobial substances and vitamins essential to living beings.