Scielo RSS <![CDATA[Brazilian Archives of Biology and Technology]]> vol. 55 num. 3 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Efficient Regeneration of <i>Eucalyptus urophylla </i>x<i> Eucalyptus grandis</i> from Stem Segment</b>]]> The aim of the present study was to establish an efficient regeneration system for the hybrid E. urophylla x E. grandis by means of organogenesis. Stem segments from seedlings were used as explants and cultured in a modified Murashige and Skoog medium (MS), supplemented with 13.2 µM N-phenyl-N'-[6-(2-chlorobenzothiazol)-yl] urea (PBU) and 0.285 µM indole-3-acetic acid (IAA). PBU was a useful growth regulator. After cultivating for 5 d, 96% explants formed callus. After 30 d, the calli obtained were transferred to MS medium containing different combinations of 6-benzyladenine (BA) and naphthalene acetic acid (NAA). Compared with other growth regulator combinations, PBU stimulated more vigorous calli and restrained browning. In addition, a large percentage (91.3%) of the calli induced by PBU showed adventitious buds formation. Shoot elongation was then stimulated on half-strength MS mineral salts medium supplemented with 6.6 µM PBU and 0.285 µM IAA for 20 d. For rooting, the elongated shoots were cultivated on root induction medium containing 2.46 µM indole-3-butyric acid (IBA). Plantlets were then successfully transplanted to a greenhouse. This procedure represented an efficient way of E. urophylla x E. grandis plant regeneration. <![CDATA[<b>Micropropagation of an elite F1 watermelon (<i>Citrullus lanatus</i>) hybrid from the shoot tip of field grown plants</b>]]> The aim of this work was to develop a protocol for rapid micropropagation of an elite F1 hybrid watermelon cultivar using shoot tip of field-grown plants. Maximum frequency (73%) of shoot tip showed growth response in MS medium supplemented with 5 mg l-1 benzyl adenine (BA) and 0.1 mg l-1 indole-3 acetic acid (IAA). Upon transfer to cytokinin-enriched medium, the cultures produced multiple shoots and 2.0 mg l-1 BA was optimum in this respect. Addition of gibberellic acid (GA3) in the multiplication medium resulted in better growth of shoots. Rooting rate was 100% when shoots were obtained from second subculture were cultured in medium with 1.0 mg l-1 indole-3 butyric acid (IBA). The shoots produced more roots with increasing number of subcultures. About 72% of the regenerated plantlets acclimatized successfully and survived in the soil condition. <![CDATA[<b>Patent application in biotechnology at subclass C12N in Brazil at the period of 2001 to 2005</b>]]> An analysis of Instituto Nacional de Propriedade Industrial (INPI) patent database from 2001 to 2005 showed that less than 5% of the total patent deposited in the subclass C12N, which referred to "Microorganisms or Enzymes, Compositions thereof, Propagating, Preserving or Maintaining Microorganisms, Mutation or Genetic Engineering, Culture Media", were from national depositors. In contrast, more than 34% of all these deposits came from the United States of America during the same period. Among the national depositors, public universities and government research institutions contributed with 83% over all the deposits, demonstrating that research and development in the field of Biotechnology in Brazil has been concentrated within Brazilian public institutions during this period. <![CDATA[<b>Phenotypic Diversity of Apple <i>(Malus</i> sp.<i>)</i> Germplasm in South Serbia</b>]]> To determine the overall degree of polymorphism, detect similarities among the accessions and collect highly valued genotypes of native apples, 21 characters of 18 autochthonous apple cultivars were studied for three years. Particular individual accessions were selected from the south region of Serbia according to economically valuable characters and tested in situ. Agronomic evaluation of germplasm accessions revealed considerable diversity among different accessions for all the characters studied. The analysis of variance revealed significant differences among the accessions and among years for some characters as well. Cluster analysis distinguished Malus sp. accessions into three distinct groups. Despite of the significant differences among the accessions, yield and fruit weight were a clear separation between the clusters. Among the germplasm of a small geographic area, it was possible to find the cultivars with valuable morphological traits that could be immediately distributed to the market or employed in breeding programs. <![CDATA[<b>Relationships of photosynthetic photon flux density, air temperature and humidity with tomato leaf diffusive conductance and temperature</b>]]> The objective was to study the leaf temperature (LT) and leaf diffusive vapor conductance (gs) responses to temperature, humidity and incident flux density of photosynthetically active photons (PPFD) of tomato plants grown without water restriction in a plastic greenhouse in Santa Maria, RS, Brazil. The plants were grown in substrate and irrigated daily. The gs was measured using a steady-state null-balance porometer on the abaxial face of the leaves during the daytime. Both leaf surfaces were measured in one day. The PPFD and LT were measured using the porometer. Leaf temperature was determined using an infrared thermometer, and air temperature and humidity were measured using a thermohygrograph. The leaves on the upper layer of the plants had higher gs than the lower layer. The relationship between the gs and PPFD was different for the two layers in the plants. A consistent relationship between the gs and atmospheric water demand was observed only in the lower layer. The LT tended to be lower than the air temperature. The mean value for the gs was 2.88 times higher on the abaxial than adaxial leaf surface. <![CDATA[<b>Comparison between deep intracornual artificial insemination (dIAI) and conventional artificial insemination (AI) using low concentration of spermatozoa in beef cattle</b>]]> This study aimed to compare the pregnancy rate using the conventional artificial insemination (AI) or deep intracornual artificial insemination (DIAI), with low number of spermatozoa (4.0 million sperm) in 270 Nelore cows. The animals were divided in two groups (G: G1 (135 cows) conventional AI was performed (=semen deposition in the uterine body) and in G2 (135 cows) to DIAI, in ipsilateral horn where the dominant follicle in the ovary had previously been detected, by ultrasound examinations. For both the methods, a single artificial insemination was carried out after visual estrus observation, checked three times a day (morning, afternoon and evening). The pregnancy diagnosis after 45 days was conducted by ultrasound. Results showed a better pregnancy rate in the DIAI group (67.4% - p<0.01), when compared to conventional AI (48.8%) with low spermatozoa concentration. <![CDATA[<b>Detection of Lsr2 gene of <i>Mycobacterium leprae</i> in nasal mucus</b>]]> In the present study, nasal mucus from patients with leprosy were analyzed by PCR using specific primers for Lsr2 gene of Mycobacterium leprae. The presence of Lsr2 gene in the nasal mucus was detected in 25.80% of patients with paucibacillari leprosy, and 23.07% of contacts. Despite the absence of clinical features in the contact individuals, it was possible to detect the presence of Lsr2 gene in the nasal mucus of these individuals. Therefore, PCR detection of M. leprae targeting Lsr2 gene using nasal mucus samples could contribute to early diagnosis of leprosy. <![CDATA[<b>Determination of eye irritation potential of low-irritant products</b>: <b>comparison of <i>in vitro</i> results with the <i>in vivo</i> draize rabbit test</b>]]> In an attempt to build the evaluation strategies to assess the human eye irritation, a reassessment of some in vitro tests is necessary, particularly concerning the non-irritants, mild and moderate irritants. Thus, the correlations between results obtained from the Draize test with the in vitro methods HET-CAM (Hens Egg Test-Chorion Allantonic Membrane) and RBC haemolysis assay to assess the ocular irritancy potential of 20 eye drops were examined. Parameters such as accuracy (%) and specificity (%) were determined. All results were correlated with RBC correctly with the results obtained in the Draize test. The HET-CAM presented four false-positive results, showing a tendency of data overestimation. Despite the high specificity provided mainly by the RBC, it would be necessary to test a wider range of products representing all the scales of irritation to confirm its ability to be used as a first alternative to test products that could be presumptive non-irritants. <![CDATA[<b>Infliximab treatment prevents hyperglycemia and the intensification of hepatic gluconeogenesis in an animal model of high fat diet-induced liver glucose overproduction</b>]]> The effect of infliximab on gluconeogenesis in an animal model of diet-induced liver glucose overproduction was investigated. The mice were treated with standard diet (SD group) or high fat diet (HFD group). HFD group were randomly divided and treated either with saline (100 µl/dose, ip, twice a day) or infliximab (10 µg in 100 µl saline per dose, ip, twice a day, i.e., 0.5 mg/kg per day). SD group also received saline. The treatment with infliximab or saline started on the first day of the introduction of the HFD and was maintained during two weeks. After this period, the mice were fasted (15 h) and anesthetized. After laparotomy, blood was collected for glucose determination followed by liver perfusion in which L-alanine (5 mM) was used as gluconeogenic substrate. HFD group treated with saline showed higher (p < 0.05) liver glucose production from L-alanine and fasting hyperglycemia. However, these metabolic changes were prevented by infliximab treatment. Therefore, this study suggested that infliximab could prevent the glucose overproduction and hyperglycemia related with glucose intolerance and type 2 diabetes. <![CDATA[<b>Antifouling effect of bioactive compounds from marine sponge <i>Acanthella elongata</i> and different species of bacterial film on larval attachment of <i>Balanus amphitrite</i> (cirripedia, crustacea)</b>]]> The antifouling activity of bioactive compounds from marine sponge Acanthella elongata (Dendy) and five species of bacterial biofilm were studied. Larvae of Balanus amphitrite (Cyprids and nauplii) were used to monitor the settlement inhibition and the extent to which inhibition was due to toxicity. The crude extract and partially purified fractions of A.elongata showed significant inhibition over the settlement individually, and with the interaction of bacterial species. No bacterial film stimulated the barnacle settlement. The high but variable levels of antifouling activity in combination with less amount of toxicity showed the potential of these metabolites in environmentally-friendly antifouling preparations. <![CDATA[<b>Interannual and seasonal variability of macroinvertebrates in monsoonal climate streams</b>]]> The aim of this study was to assess the interannual and seasonal changes in the community composition, abundance and presence-absence of macroinvertebrates in the streams of the northwestern of Argentina. The importance of environmental variability in determining these changes was also analyzed. Macroinvertebrates were collected in eleven streams during high (March) and low (September) water periods during two years. Physical variables and water parameters were also recorded at each site. Community composition and abundance differed significantly between seasons, but the presence-absence data did not exhibit a clear pattern of seasonal change. Rapid recolonization of disturbed substrate could ensure the recuperation of benthic community. Small body sizes, short life cycles and continous reproduction could be important strategies that ensure the rapid resilience and persistence of macroinvertebrate assemblages in time. <![CDATA[<b>Physiological Responses of Callus from <i>Gerbera jamesonii</i> Bolus ex. Hook f. to Gamma Irradiation</b>]]> In the present study, in vitro mutagenesis techniques were applied to investigate the effects of gamma irradiation at 0, 10, 20, 30, 40, 50 and 60 Gy on physiological changes in callus of Gerbera jamesonii Bolus ex. Hook f. Biochemical changes in chlorophyll and soluble protein content of pre- and post- irradiated Gerbera callus were studied. Non-irradiated callus demonstrated the highest amount of chlorophyll content as compared to callus irradiated at 10, 20, 30, 40, 50 and 60 Gy. In addition, the amount of chlorophyll b was relatively higher than chlorophyll a in both the irradiated and non-irradiated callus, except for callus irradiated at 10 Gy. Biochemical differentiation based on total soluble protein content revealed gradual reduction after day 9 of exposure to gamma irradiation. Reduction of soluble protein content was observed in all the treatments as the increase of incubation period. <![CDATA[<b>Tolerance of <i>Anadenanthera peregrina</i> to <i>Eucalyptus camaldulensis</i> and <i>Eucalyptus grandis</i> essential oil as condition for mixed plantation</b>]]> With the purpose of selecting the species of woody Caatinga for mixed plantations with Eucalyptus spp., the allelophatic effects of E. camaldulensis and E. grandis essential oil were studied on the growth activities of Anadenanthera peregrina. The plants were closed in glass chambers in the presence of volatile oil of E. camaldulensis or E. grandis at the concentration of 13 The number of leaves, height and diameter at soil lever were compared before, immediately after and after 30 days. Chlorophyll a and b, carotenoids and dry mass were evaluated after the treatment application. There was no inhibitory effect of E. camaldulensis and E. grandis oils on A. peregrina. E. camaldulensis, which was more adapted to semi-arid conditions, was planted in mixture stands with two native legume species, inoculated with Rhizobium and arbuscular mycorrhizal fungi. E. camaldulensis did not inhibit native species growth after two years of cultivation. <![CDATA[<b>Advantages and Applications of Cryopreservation in Fisheries Science</b>]]> Cryopreservation is a long-term storage technique to preserve the biological material without deterioration for extended period of time at least several thousands of years. The ability to preserve and store both maternal and paternal gametes provides a reliable source of fish genetic material for scientific and aquaculture purposes as well as for conservation of biodiversity. Successful cryopreservation of fish sperm have been achieved for more than 200 fish species and many fish species have been adequated for the purpose of cryobanking. Cryopreservation of fish embryo is not viable, mainly because of the same limitations as in fish oocytes, i.e., high chilling sensitivity and low membrane permeability. However, cryopreservation of isolated embryonic cells is another option for preserving both maternal and paternal genome. In this paper, an overview of the current state of aquatic species is followed by a discussion on the sperm, embryos, oocytes and embryonic cells - blastomeres. <![CDATA[<b>Antimicrobial activity of lactic acid bacteria and the spectrum of their biopeptides against spoiling germs in foods</b>]]> The objective of this study was to isolate LAB from dairy, meat products and agro-industrial wastes and to investigate their antagonist activity. A total of 141 isolates were screened for the inhibitory effect on ten indicator strains in the agar spot test. Results showed that strain LBbb0141 contained antimicrobial compound with wide spectrum that inhibited the growth of ten indicator Gram-positive and Gram-negative strains. The bacteriocin activity attained its maximum value using the MRS agar at initial pH 7.5 and 30°C incubation temperature. <![CDATA[<b>Ractopamine as a metabolic modifier feed additive for finishing pigs</b>: <b>a review</b>]]> The β-adrenergic agonist ractopamine is increasingly used in the swine industry due to higher consumer demand for leaner pork products. Redirecting nutrients to favor leanness rather than fat deposition, ractopamine improves growth and carcass traits of finishing pigs. However, the impact of this agonist on pork quality is not clearly defined. Understanding the biological effects of dietary ractopamine dose, treatment period, lysine levels, and the lysine to metabolizable energy ratio will help pork producers achieve improvements in animal performance, carcass leanness, and economic efficiency in swine production systems. <![CDATA[<b>Fast assessment of mineral constituents in grass by inductively coupled plasma optical emission spectrometry</b>]]> A method for evaluating inorganic constituents in the grass by ICP OES is proposed. The samples were digested with nitric acid plus hydrogen peroxide in a microwave system. Seventeen samples were collected in the metropolitan area of Curitiba and Castro in the Paraná State, Brazil. The following elements were studied: Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se and Zn. The linear coefficients of the curves were higher than 0.999 and the precision, expressed as the relative standard deviation, which was below 10%, being considered adequate. The accuracy was validated by using the recovery test (recoveries from 80 to 107%) and by the analysis of botanical certified materials. For one sample, two other digestion procedures, using two different mixtures of nitric and hydrochloric acids, produced results in agreement with the adopted procedure. Eleven out of the twenty studied elements could be quantified in real samples. High concentrations of Ca, K, Mg and P, the essential elements for bovines and other animals, were found. The results were evaluated using the principal component analysis that gathered the samples in three groups, according to the areas where the plants were grown. <![CDATA[<b>Viability in the production of a drug extracted from <i>Ananas comosus</i> by a flat membrane system</b>]]> The aim of this work was to study the production of e bromelain from the Ananas comosus L. Merril, by determining the process conditions using flat membranes. The production system modeling generated a hyperbolical curve and the optimization by response surfaces showed an influence of the transmembrane pressure higher than the pH influence. The cost of the production of bromelain from A. comosus was estimated 9 to 13 times lower than Sigma's retail sales price and 6.5 to 8.5 times lower than when this enzyme was obtained through a liquid-liquid extraction, which showed the economical feasibility of the process. <![CDATA[<b>Decolourization of textile dye effluent by non-viable biomass of <i>Aspergillus fumigatus</i></b>]]> The aim of this work was to study the decolourization of textile dye effluent by non-viable biomass of Aspergillus fumigates. The dried non-viable fungal biomass exhibited maximum dye removal at pH 7.0 with temperature of 30ºC and 3 g/l (w/v) biomass concentration, after 24 h contact time. The results showed that the non-viable biomass possessed high efficiency for dye removal from textile effluent. <![CDATA[<b>Using fluid bed granulation to improve the dissolution of poorly water-soluble drugs</b>]]> In this study, fluid bed granulation was applied to improve the dissolution of nimodipine and spironolactone, two very poorly water-soluble drugs. Granules were obtained with different amounts of sodium dodecyl sulfate and croscarmellose sodium and then compressed into tablets. The dissolution behavior of the tablets was studied by comparing their dissolution profiles and dissolution efficiency with those obtained from physical mixtures of the drug and excipients subjected to similar conditions. Statistical analysis of the results demonstrated that the fluid bed granulation process improves the dissolution efficiency of both nimodipine and spironolactone tablets. The addition of either the surfactant or the disintegrant employed in the study proved to have a lower impact on this improvement in dissolution than the fluid bed granulation process.