Scielo RSS <![CDATA[Brazilian Archives of Biology and Technology]]> vol. 57 num. 5 lang. es <![CDATA[SciELO Logo]]> <![CDATA[Endophytes: exploitation as a tool in plant protection]]> Endophytes are symptomless fungal or bacterial microorganisms found in almost all living plant species reported so far. They are the plant-associated microbes that form symbiotic association with their host plants by colonizing the internal tissues, which has made them valuable for agriculture as a tool in improving crop performance. Many fungal endophytes produce secondary metabolites such as auxin, gibberellin etc that helps in growth and development of the host plant. Some of these compounds are antibiotics having antifungal, antibacterial and insecticidal properties, which strongly inhibit the growth of other microorganisms, including plant pathogens. This article reviews the endophyte isolated from different plants, mode of endophytic infection and benefits derived by the host plant as a result of endophytism. <![CDATA[Growth of microalgae <em>Scenedesmus</em> sp in ethanol vinasse]]> This study evaluated the feasibility of using vinasse as a nutrient source for microalgae cultivation. The Scenedesmus sp was grown in a medium supplemented with vinasse and process variables were optimized using a factorial design and a Central Composite Design (CCD). The factorial design results showed that it was possible to cultivate microalgae at concentrations of up to 40% of vinasse in the culture medium. The CCD results showed that the light intensity and vinasse concentration influenced the amount of biomass produced. <![CDATA[Influence of calcium content of tissue on hyperhydricity and shoot-tip necrosis of in vitro regenerated shoots of Lavandula angustifolia Mill.]]> In the present study, the effects of two CaCl2.2H2O levels (440 and 1320 mg L-1) and two subcultures were evaluated on in vitro shoots of Lavandula angustifolia cv. Provence Blue. Ca2+ content of the apical, middle and basal portion of shoots was determined. Increasing CaCl2.2H2O level in the culture medium increased tissue Ca2+ content and decreased hyperhydricity. Shoot-tip necrosis also decreased with 1320 mg L-1 CaCl2.2H2O, but it did not occur in the second subculture. The middle and basal portion had higher Ca2+ content than apical portion. In non-hyperhydric tissues, there were smaller and more juxtaposed cells. Scanning electron microscopy of the leaves demonstrated that trichomes from in vitro leaf surface occurred in smaller quantities. <![CDATA[Mixed Cultures Fermentation for the Production of Poly- ß-hydroxybutyrate]]> Poly-ß-hydroxybutyrate (PHB) is a biodegradable intracellular microbial product produced by many bacteria and it is comparable to some of the petrochemical derived thermoplastics such as polypropylene. One of the main barriers for the commercial exploitation is the high cost of the substrate for the production of biopolymer. The utilization of mixed microbial cultures facilitates the use of complex substrates thereby reducing the cost of PHB production. In the present study, mixed culture systems were evaluated for PHB production. Bacillus firmus NII 0830 was used for the production of PHB since it accumulates a large amount of PHB and a second organism Lactobacillus delbrueckii NII 0925 was used to provide lactic acid. FTIR and 1H NMR analyses revealed that the PHB extracted from pure culture and mixed culture showed exact match to that of standard PHB. Biodegradation studies of the PHB blends showed 87% degradation. It was also found that a consortium of organisms degraded the films faster than a single organism. <![CDATA[Optimization of fibrinolytic protease production from Bacillus subtilis I-2 using agro-residues]]> The aim of this work was to study the production of fibrinolytic protease by Bacillus subtilis I-2 on agricultural residues. Molasses substantially enhanced (63%) protease production (652.32 U/mL) than control (398.64 U/mL). Soybean meal supported maximum protease production (797.28 U/mL), followed by malt extract (770.1 U/mL), cotton cake (761.04 U/mL), gelatin (742.92 U/mL) and beef extract (724.8 U/mL). Based on the Plackett-Burman designed experiments, incubation time, soybean meal, mustard cake and molasses were identified as the significant fermentation parameters. Ammonium sulfate precipitation and DEAE sephadex chromatography resulted 4.8-fold purification of protease. Zymography showed the presence of three iso-forms in the partially purified protease preparation, which was confirmed by the SDS-PAGE analysis (42, 48, 60 kDa). Protease exhibited maximum activity at 50oC and at pH 8.0. Significant stability was observed at 30-50oC and at pH 7.0-10.0. Mg2+, Zn2+, Co2+, Ca2+, Mn2+ and Cu2+,EGTA, EDTA and aprotinin severely decreased the enzyme activity. <![CDATA[Physico-chemical characterization of Ilex paraguariensis St. Hil. during the maturation]]> In Brazil, yerba mate is consumed after processing; however, in Chile and Uruguay, the consumers prefer the cured product, which acquires a yellow color. For that yerba-mate is stored for a period of six months to one year, which increases the cost of the final product for the overseas market. This study evaluated the effect of humidity and temperature in maturation chamber on the time required for the product to get this characteristic. The changes in the color, pH, moisture and water activity were evaluated during the time of storage in different conditions of temperature and humidity. Yerba-mate subjected to higher temperature and humidity showed nearest color of the product submitted to natural storage. The loss of green color was related to the reduction in pH and increase in the moisture of the samples. The higher humidity allowed the mate to reach conditions near to market requirements abroad in approximately 60 days of maturation. <![CDATA[Use of the arbuscular mycorrhizal fungus Glomus intraradices as biological control agent of the nematode Nacobbus aberrans parasitizing tomato]]> The plant-parasitic nematode Nacobbus aberrans is an endoparasite that induces gall formation in the roots and causes severe losses to diverse crops. Some populations of this nematode show preference for certain hosts, revealing the existence of "races/groups" with different behaviour and making nematode management difficult. A possible biological control alternative to reduce the damage caused by this species may be the use of arbuscular mycorrhizal fungi (AMF). In the present work, the effect of Glomus intraradices on tomato plants inoculated with the nematode at transplanting and three weeks later was tested. At 60 days, the following parameters were estimated: percentage of AMF colonization, root and aerial dry weight, number of galls and egg masses, and reproduction factor (RF=final population/initial population) of N. aberrans. AMF colonization was higher in the presence of the nematode. The use of AMF favoured tomato biomass and reduced the number of galls and RF on the plants inoculated with the nematode at transplanting. <![CDATA[Antitumor activity of C-phycocyanin from Arthronema africanum (Cyanophyceae)]]> Pure C-phycocyanin (C-PC) was isolated from Arthronema africanum to evaluate its potential antitumor effects in vivo and in vitro. Experimental myeloid Graffi tumor in hamsters was used as a model. The cell proliferation assay showed that C-PC treatment, at concentration of 100 µg mL-1 for 24 h, significantly inhibited the growth of Graffi tumor cells (51.4% viability). Agarose gel electrophoresis of the genomic DNA of treated cells displayed time-and concentration-dependent fragmentation pattern, typical for apoptosis. Apoptotic process was related to the increase in cellular manganese and copper/zinc superoxide dismutases and glutathione reductase activities, coupled with a low catalase activity. In vivo C-PC administration (5.0 mg kg-1 body weight) suppressed the tumor transplantability and growth, while the mean survival time of the tumor-bearing hamsters was increased. The results revealed promising antitumor activities of A. africanum C-PC and suggested the potential of this natural biliprotein pigment for future pharmacological and medical applications. The study provided new data on the mechanism of the C-PC induced apoptosis in which the imbalance of antioxidant enzymes that favoured hydrogen peroxide accumulation might play a leading role. <![CDATA[Current status of rodenticide intoxication in Brazil: a preliminary survey from 2009 to 2011]]> The chemical control of rodents with anticoagulant products, especially derivatives of the coumarin chemical group, is legally authorised in Brazil. These products provide effective control and are safe for humans. However, the use of illegal 'rodenticides' has increased in many Brazilian cities recently, accompanied by increased numbers of suicides, homicides, and intoxications. The National Toxicology Information System (Sinitox) registers the number of rodenticide intoxications, including suicides, but does not differentiate between the legal and illegal rodenticides. Intoxications by rodenticides outnumber those by illicit drugs and pesticides. A survey of data from 2005-2011 revealed an average of about 3,800 intoxications per year, about 60% of which were suicides. Many of these intoxications probably involved illegal rodenticides, some with unknown chemical compositions, which confound the data on rodenticide intoxication. This evaluation of Sinitox data highlighted the need to ensure the proper use of the term 'rodenticide' when registering intoxication cases. Intoxication by-products that are not rodenticides, but are erroneously used for this purpose, should be classified separately to improve the quality of information. <![CDATA[Molecular docking of Anopheles gambiae and Aedes aegypti glutathione S-transferases epsilon 2 (GSTE2) against usnic acid: an evidence of glutathione conjugation]]> The aim of this study was to develop a theoretical model using Anopheles gambiae GSTE2 structure as template for Aedes aegypti GSTE2 by homology modeling Docking simulations were performed for both the enzymes against usnic acid in neutral and anionic forms. Ramachandran plot revealed that 93.9% of the GSTE2 model residues were located on most favored regions. Model evaluation was made by the ANOLEA and GROMOS analysis. Docking results indicated that the enzymes were able to form glutathione-conjugate with usnic acid in both the forms (anionic and neutral). <![CDATA[Performance of calves submitted to protocols using extruded or ground starter]]> Feed processing can affect rumen development in new born calves, and potentially define animal performance. Two feed management systems, extruded starter (Ruter) with possible early weaning and ground starter (control), were evaluated in thirty-two Holstein calves (16 females and 16 males). Animals were randomly assigned to the treatments using a randomized block design with birth weight as a covariate. They were weaned when starter intake reached 800 g for two consecutive days. Twenty-one days after the weaning, males were slaughtered and the stomach compartments were isolated. Rumen and omasum fragments were processed for morphological evaluation. Animal performance, clinical condition and stomach compartment weight did not differ between the treatments (P&gt; 0.05), despite weaning weight of animals receiving extruded starter being 5.68% higher than the control animals. Extruded starter stimulated cell proliferation of the ruminal epithelium (P &lt;0.05), but did not affect the dimensions of the papillary rumen and omasum mitotic index (MI). The Ruter feeding system was potentially beneficial for weight gain and morphofunctional rumen development in lactating animals; however, this treatment did not allow early weaning as proposed by the feeding system. <![CDATA[Pre-eclampsia: a life-threatening pregnancy syndrom]]> Pre-eclampsia is a serious pathological state affecting 5-10% of pregnant women. Currently, it is diagnosed in the second half of pregnancy, particularly after the 20th week. Symptoms mostly correspond to the changes of blood vessels and kidneys. The severity of pre-eclampsia is proportional to symptomatic manifestations, thus the more symptoms present, the higher is of pre-eclampsia development. Although there are several studies dealing with pre-eclampsia pathology, the complete etiology is still unknown. In this review paper, several theories are presented and discussed. <![CDATA[Date and their processing byproducts as substrates for bioactive compounds production]]> Date is the most popular fruit in middle-east countries. However, the date production process is accompanied by a substantial increase of loss during picking, storage, commercialization and conditioning process. Date and their byproducts have many essential elements for the growth of microorganisms. Thus, they can be converted into value-added compounds through biotechnology. In this paper, date and their processing byproducts used as substrates for producing value-added products such as organic acids, exopolysaccharide, antibiotics, date flavored probiotic fermented dairy, bakery yeast, etc, were reviewed. <![CDATA[Endophytic fungi found in association with Bacopa monnieri as potential producers of industrial enzymes and antimicrobial bioactive compounds]]> This study aimed to screen the endophytic fungal species of ethano-medicinal plant Bacopa monnieri (L.) Pennell for their ability to produce antimicrobial substances against Bacillus subtilis, Pseudomonas aeroginosa, Salmonella typhimurium, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, and Candida albicans. Endophytes were also screened for their ability to produce amylase, cellulase, protease and lipase to evaluate their ecological role within the host plant. Twenty-six endophytes were isolated and seventeen were identified. All the isolated endophytes exhibited amylolytic activity. Lipolytic, cellulolytic, proteolytic activity was shown by 98, 28 and 31% isolates, respectively. Similarly, all the endophytes (100%) exhibited significant antimicrobial activity against K. pneumonia, while seventeen endophytes (89.5%) were active against S. aureus. Fourteen endophytes (78.9%) showed significant antimicrobial activity against B. subtilis and C. albicans. Eleven (57.8%), nine (50%), four (21%) endophytes were active against S. typhimurium, E. coli and P. aeruginosa, respectively. <![CDATA[Filamentous fungi isolated from Brazilian semiarid tolerant to metallurgical industry wastes: an ex situ evaluation]]> The purpose of this study was to assess the impact of metallurgical industry wastes on the semiarid soil microbiota using physico-chemical and microbiological parameters, highlighting the filamentous fungi assembly. Soil samples were collected in an area of industrial waste deposit contaminated with lead and mixed with natural soil (control soil) in seven different concentrations (0, 7.5, 15, 30, 45, 60 and 100%). The results showed alterations on the physico-chemical properties of the soil treated with industrial wastes, with a gradate increase of the soil's pH (5.6-10.4) and electrical conductivity (0.3-14.7 dS m-1) and also reduction of organic matter (7.0-1.8%). The use of microbiological parameters (fungal richness and diversity, CO2 emission, and the carbon on the microbial biomass) enabled the identification of alterations on the microbial community due to stress caused by the exposure to industrial wastes, despite the presence of Thielavia, Chaetomium and Aspergillus tolerant to high concentrations of the scoria. Therefore, these filamentous fungi could be used in biomonitoring and bioremediation studies in the soils contaminated by industrial wastes. <![CDATA[Molecular characterization of arabica and Conilon coffee plants genotypes by SSR and ISSR markers]]> The molecular characterization of ten genotypes of the Coffea arabica plants and of seven genotypes of C. canephora having interesting features for coffee breeding programs was carried to select the parents for breeding. A total of 40 SSR and 29 ISSR primers were used. The primers generated a total of 331 (307 polymorphic and 24 monomorphic) bands. Analysis of genetic diversity presented dissimilarity intervals ranging from 0.22 to 0.44 between the Conilon genotypes, from 0.02 to 0.28 between the Arabica genotypes, and from 0.49 to 0.60 between the genotypes of the two species in the joint analysis. Four groups were formed: I = genotypes of C. arabica, II = four progenies of C. canephora, Conilon group, and one non defined C. canephora (Conilon or Robusta), III = one progeny of un-defined C. canephora (Conilon or Robusta) and IV = one progeny of C. canephora of Robusta group. The grouping formed was consistent with the origins of each group. High stabilities of the bifurcations were found by bootstrap analysis. The use of molecular markers of the SSR and ISSR types in the diversity study was efficient in distinguishing genotypes between and within C. arabica and C. canephora. <![CDATA[Activity of encapsulated Lactobacillus bulgaricus in alginate-whey protein microspheres]]> In this work, alginate-whey protein was used as wall materials for encapsulating Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus). The characteristics of encapsulated and free L. bulgaricus showed that the free L. bulgaricus lost viability after 1 min exposure to simulated gastric fluid (SGF) at pH 2.0 and 2.5. However, the viability of encapsulated L. bulgaricus did not decrease in SGF at pH 2.5 for 2 h incubation. The viable numbers of encapsulated L. bulgaricus decreased less than 1.0 log unit for 2 h incubation in SGF at pH 2.0. For bile stability, only 1.2 log units and 2.0 log units viability of the encapsulated L. bulgaricus was lost in 1 and 2% bile for 1 h exposure, respectively, compared with no survival of free L. bulgaricus under the same conditions. Encapsulated L. bulgaricus was completely released from the microspheres in simulated intestinal fluid (SIF, pH 6.8) in 3 h. The viability of the encapsulated L. bulgaricus retained more 8.0 log CFU/g after stored at 4°C for four weeks. However, for free L. bulgaricus, only around 3.0 log CFU/mL was found at the same storage conditions. Results showed that the encapsulation could improve the stability of L. bulgaricus. <![CDATA[Effect of CLA supplementation to low-protein diets on the growth performance, carcass characteristics, plasma urea nitrogen concentration, and fatty acid profile in the meat of pigs]]> To analyze the effect of conjugated linoleic acid (CLA) on the meat of pigs (0,1%) and three crude protein (CP) levels (nursery: 20.5, 16.0, 14.5%; growing: 16, 14.5, 11.5%; and finishing: 14.0, 12.5, 11% CP), studies were conducted with 36 hybrid (Yorkshire×Landrace×Duroc) barrows (17.3-83.5 kg), which were individually penned and allotted in a completely randomized design in a factorial (2×3) arrangement for 84 d. The analysis by phases indicated that CP level affected some variables. Average daily gain, average daily feed intake, fat free lean gain, backfat thickness, longissimus muscle area and final body weight were reduced (P≤0.05) feeding the lowest CP diet in nursery and growing pigs. Plasma urea nitrogen concentration was also lower (P≤0.05) in the growing and finishing phases when fed the lowest CP level. The global analysis showed that all the analyzed variables (except feed gain ratio, lean meat percentage and plasma urea nitrogen concentration) were reduced (P≤0.05) in the pigs fed low-protein diets; plasma urea nitrogen concentration tended to be lower (P=0.07) when CP was reduced. The fatty acid profile of the meat (semimembranosus and longissimus muscles) indicated that CLA addition increased CLA isomers and total saturated fatty acids, and reduced the total monounsaturated fatty acids (P≤0.05). α-Linolenic acid was lowered in longissimus muscle of pigs fed LPD (P=0.08). These results indicated that reducing the crude protein concentration in the diet of fattening pigs from 20.5 to 16.0% in nursery phase; from 16.0 to 14.5% in growing stage; and from 14.0 to 12.5% in finishing pigs, did not negatively affect the growth performance, nor carcass characteristics. The results also showed that the addition of CLA did not improve pig response and the concentration of unsaturated fatty acids and total lipids altered the feeding LPD. <![CDATA[Evaluation of probiotic properties of Pediococcus acidilactici B14 in association with Lactobacillus acidophilus ATCC 4356 for application in a soy based aerated symbiotic dessert]]> The aim of this study was to evaluate the probiotic properties of Pediococcus acidilactici B14 and to study its resistance in the gastrointestinal system when combined with Lactobacillus acidophilus ATCC 4356 and used in a potentially symbiotic aerated soy based dessert. P. acidilactici B14 showed some important probiotic characteristics such as survival rate of 45.9% at pH 2.5; 72.4% in 0.3% bile salts and 95.8% after gastrointestinal transit at pH 4.0. Tolerance against the antibiotics cephalexin, neomycin, vancomycin, cefotaxime and penicillin G was also observed. The strain inhibited antagonism against the following cultures: Escherichia coli ATCC 25922, Bacillus cereus ATCC 33018, Staphylococcus aureus ATCC 6538P and Salmonella sp. The mixed culture of P. acidilactici B14 with L. acidophilus ATCC 4356 showed a survival rate of 92.4% after the passage through the gastrointestinal system at pH 4.0. Furthermore, in the presence of the food matrix, an average increase in cell viability, after being subjected to the gastrointestinal system of 9.9% at pH 2.0 and 6.1% at pH 4.0, was observed. This characterized the adequacy of the associated culture as probiotic in the development of a functional food such as soy based aerated symbiotic dessert. <![CDATA[Soybean β-Glucosidase immobilisated on chitosan beads and its application in soy drink increase the aglycones]]> The objective of this study was to investigate the immobilisation efficiency of soybean β-glucosidase (181.6 U/mL; 23.8 mg protein/mL) on activated chitosan beads. Central Composite Rotational Design (CCDR) 23 was used and the application of immobilised enzyme in commercial soy drink was evaluated. The activation of chitosan beads was achieved with established 2.5% glutaraldehyde, pH 7.5, 8 h incubation time (6 h with agitation and 2 h without agitation) at 37ºC. The highest immobilisation efficiency (%) of soybean β-glucosidase on chitosan beads obtained was 37.74 U/mL and 18.84 mg protein/4 chitosan beads at pH 7.5 and 20 h coupling time of enzyme-matrix (7 h with agitation and 13 h without agitation) at 4ºC. The immobilised enzyme incubated at 50ºC, pH 5.5 resulted in 24% increase in the aglycones content in commercial soy drink after 60 min. <![CDATA[Does adaptive strategy for delayed seed dispersion affect extinction probability of a desert species? an assessment using the population viability analysis and glass house experiment]]> Canopy seed bank is an important adaptive evolutionary trait that provides various types of protection to the seeds. However, costing of such evolutionary trait on plant survival is largely unknown. Present investigation provided a new insight on the serotonious habit of Blepharis sindica associated with its endangerment status. Extinction probabilities of two available population of B. sindica were quantified using two types of census data, i.e., fruiting body number and actual population size. Population Viability Analysis (PVA) revealed that delayed seed release tendency (higher fruiting body number) was not synchronized with actual ground conditions (lower population size). PVA analysis based on actual population size indicated that both the available populations would vanish within 20 years. The mean time of extinction calculated from both type census data indicated its extinction within 48 years. For assessing the conservation criteria, a glass house experiment was carried out with different soil types and compositions. Pure sand and higher proportions of sand -silt were more suitable compared to clay; further, gravelly surface was the most unsuitable habitat for this species. Collection of the seeds from mature fruits/capsule and their sowing with moderate moisture availability with sandy soil could be recommended. <![CDATA[Biofiltration of a styrene/acetone vapor mixture in two reactor types under conditions of styrene overloading]]> This aim of study was to compare the performance of a biofilter (BF) and trickle bed reactor (TBR) under increased styrene loading with a constant acetone load, 2 gc/m3/h. At styrene loading rates up to 30 gc/m3/h, the BF showed higher styrene removal than TBR. However, the BF efficiency started to drop beyond this threshold loading and could never reach steady state, whereas the TBR continued to yield a 50% styrene removal. The acetone removal remained constant (93-98%) in both the reactors at any styrene loading. Once the overloading was lifted, the BF recovered within 26 min, whereas the TBR efficiency bounced back only to 95%, gradually returning to complete removal only in 10 h. <![CDATA[Characterization of diesel degrading bacterial species from contaminated tropical ecosystem]]> The bacterial diversity in a diesel contaminated tropical soil was investigated using diesel oxidation in gradient cultures dynamics (pH and OD) of the pure cultures. The diesel dependent growths of these isolates were assessed for 15 days by monitoring the gradient fluxes in the pH and Optical density OD of the media. Results showed an increase in OD as well as fluctuations in pH values. The mean OD data obtained was 0.515- 1.187 with pH of 6.95-7.2. From the morphological and biochemical characterization and comparison with respect to the standard references, the isolates S1P1, S3P3, S2P2, S2P1,and S3P2 were presumably the members of the genera Bacillus, Pseudomonas and Mycobacterium species. From the study, it was apparent that the tropical ecosystems contained unique organisms with the ability to deal with diesel contamination. <![CDATA[Electronic tongue system to evaluate flavor of soybean (Glycine Max (L.) Merrill) genotypes]]> An electronic tongue system was tested as a fast and efficient analytical tool for flavor evaluation of soybean genotypes. Grain samples of 25 soybean lines were analyzed using 0.25 g of milled samples added to 100 mL of distilled water and mixing for one minute on a magnetic stirrer. An aliquot (50 mL) from the filtered liquid was used for the analysis on a pre-fixed frequency of 1 kHz and alternate tension of 50 mV. Two analyses were conducted in a complete randomized design with three replicates. Electrical response (capacitance) of eight polymeric chemical sensors used to analyze the soybean lines were submitted to Principal Component Analysis (PCA). In the spatial distribution of the PCA graphic, the lines close to each other were similar, while the distant ones showed different characteristics. The electronic tongue system was efficient in discriminating flavor of soybean lines. <![CDATA[Validation of computationally predicted substrates for laccase]]> Present study reports the validation (oxidation) of computationally predicted oxidation of xenobiotic contaminants by commercially available pure laccase from Trametes versicolor. Selected contaminants were predicted as potential targets for laccase oxidation by using in-silico docking tool. The oxidation by laccase was measured by change in absorbance at specific λ max of each compound. Sinapic acid and tyrosine were taken as positive and negative controls, respectively. Oxidation was observed in m-chlorophenol, 2,4 di-chlorophenol, 2,4,6 tri-chlorophenol, captan, atrazine and thiodicarb, except malathion, which showed no activity. It could be speculated that the predicted substrates showing oxidation shared homology at structural and chemical level with positive control compounds. In case of malathion, structural non-homology with sinapic acid could be attributed to its inactivity towards laccase that required further structural analysis. Thus, a remediation tool proposing an advanced remediation approach combining the application of theoretical in-silico method and subsequent experimental validation using pure laccase could be proposed. As number and type of xenobiotics increase, the unfeasibility to screen them experimentally for bioremediation also rise. This approach would be useful to reduce the time and cost required in other screening methods.