Scielo RSS <![CDATA[Biological Research]]> http://www.scielo.cl/rss.php?pid=0716-976020130004&lang=en vol. 46 num. 4 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<strong>Editorial</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400001&lng=en&nrm=iso&tlng=en <![CDATA[<b>Are good ideas enough?</b>: <b>The impact of socio-economic and regulatory factors on GMO commercialisation</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400002&lng=en&nrm=iso&tlng=en In recent years scientific literature has seen an increase in publications describing new transgenic applications. Although technically-sound, these promising developments might not necessarily translate into products available to the consumer. This article highlights the impact of external factors on the commercial viability of Genetically Modified (GM) animals in the pharmaceutical and food sectors. Through the division of the production chain into three Policy Domains -Science, Market and Public- I present an overview of the broad range of regulatory and socio-economic components that impacts on the path towards commercialisation of GM animals. To further illustrate the unique combination of forces that influence each application, I provide an in-depth analysis of two real cases: GM rabbits producing human polyclonal antibodies (pharmaceutical case study) and GM cows producing recombinant human lactoferrin (food case study). The inability to generalise over the commercial success of a given transgenic application should encourage researchers to perform these type of exercises early in the R & D process. Furthermore, through the analysis of these case studies we can observe a change in the biopolitics of Genetically Modified Organisms (GMOs). Contrary to the GM plant biopolitical landscape, developing states such as China and Argentina are placing themselves as global leaders in GM animals. The pro-GM attitude of these states is likely to cause a shift in the political evolution of global GMO governance. <![CDATA[<strong>Cisgenesis and Intragenesis</strong>: <strong>New tools For Improving Crops</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400003&lng=en&nrm=iso&tlng=en Genetically Modified Organisms (GMO) could be the answer for many relevant problems affecting crops. However, improving crops through GMO is also often associated with safety concerns, environmental risks and health issues due to the presence of foreign DNA. These limitations have prompted the development of alternative technologies. Recently, cisgenesis and intragenesis have been developed as new tools aimed to modify crops. While cisgenesis involves genetic modification using a complete copy of natural genes with their regulatory elements that belong exclusively to sexually compatible plants, intragenesis refers to the transference of new combinations of genes and regulatory sequences belonging to that particular species. So far, application of cisgenesis and intragenesis as alternatives to conventional transgenesis are limited to a few species, mainly due to the lack of knowledge of the regulatory sequences required. The grape is one of the most cultivated crops worldwide and is the most economically relevant crop in Chile. Its genomic sequence has been completed, making available new sources of information to improve grape traits by genetic manipulation. This review is focused on the current alternatives to transgenesis in plants, including new approaches to develop marker-free crops, their application to economically relevant crops and future perspectives in the area. Also, the identification of grapevine promoters with a wide range of expression profiles is shown. The expression pattern of these genes was analyzed in different tissues and developmental stages, as well as under several stresses and stimuli, giving a broad range of expression patterns, including genes expressed exclusively during ripening, in response to sugars, senescence and biotic stress, among others. Genes with strong and constitutive expression were also identified. Functional analysis using reporter genes has been conducted in order to confirm the promoter's transcription activity, opening new possibilities for developing cisgenic/intragenic grapevines. <![CDATA[<strong>Benzothiadiazole (BTH) induces resistance to <i>Pepper golden mosaic virus</i> (PepGMV) in pepper <i>(Capsicum annuum L.)</i></strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400004&lng=en&nrm=iso&tlng=en Pepper is an economically important crop in many countries around the world but it is susceptible to many diseases. In Mexico, diseases caused by bipartite begomoviruses have emerged as important problems in pepper. Several control strategies have been explored wiht little success; most of them are based on the avoidance of virus transmission and the breeding for resistance. Abiotic inducers can act at various points in the signaling pathways involved in disease resistance, providing long-lasting, wide-spectrum resistance. Benzothiadiazole (BTH) shares the property of activating the systemic acquired resistance pathway downstream from the SA signaling. In this work, resistance to PepGMV infection was induced in pepper plants by activating the SA pathway using BTH treatment. The resistance was characterized by evaluating symptom appearance, virus accumulation and viral movement. Our results showed that BTH could be an attractive alternative to induce geminivirus resistance in pepper plants without a significant damage of the fruit quality and productivity. <![CDATA[Biological applications of honeys produced by <i>Apis mellifera</i>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400005&lng=en&nrm=iso&tlng=en Honey is a natural product with many attributes that are useful for humans. The consumption of honey is increasing because of its beneficial biological properties, including antioxidant and antibacterial activities. Even though honey is produced worldwide, many variants of this product have not been studied and their biological potential for alternative uses has not been evaluated. Because of its varied endemic native flora, Chile produces several types of honey. It is likely that these apian products have important biological properties inherited from specific floral sources, but it is absolutely necessary to conduct further chemical analyses to identify and characterize these biological attributes. Sadly, the potential antimicrobial and antitumor activities of Chilean honeys remain unproven at the present time. Further studies are needed to identify these attributes. In addition, the impact of human activities on the natural production of honey by bees should be considered. The use of honey as an environmental marker of pollution should also be considered, and care must be taken to diminish the effect of industry and human procedures on natural environments<hr/>Honey is a natural product with many attributes useful for human beings. Nowadays, the consumption of honey is increasing due to its described biological properties such as antioxidant and antibacterial activities. However, honey is produced around the world and there still are many samples of this product that have not been studied or characterized in terms of their biological potential or alternative uses. Chile produces several kinds of honey, owing to the presence of a diverse endemic native flora. These bee products appear to have important biological properties inherited from specific floral sources, but further chemical analyses directed to determine the presence of biological attributes are absolutely necessary. Sadly, many potential effects against bacteria, fungi or antitumor or antiviral activities remain unknown at the present time. Further studies may reveal those attributes in the future. Another fact to be considered is the human activities that may affect the natural production of honey by bees. Despite the limited usefulness of honeys as environmental markers of pollution, they warn that industrial and human procedures should aim to decrease their impact on natural environments. <![CDATA[<b>Using genomics to improve fruit quality</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400006&lng=en&nrm=iso&tlng=en New fruit varieties are needed to satisfy consumers, and the industry is facing new challenges in order to respond to these demands. The emergence of genomic tools is releasing information on polymorphisms that can be utilized to expedite breeding processes in species that are difficult to breed, given the long periods of time required to get new varieties. The present review describes the current stages of the ongoing efforts that are being taken to apply these technologies to obtain varieties with improved fruit quality in species of the family Rosaceae. <![CDATA[<strong>Genomic Approaches in Marine Biodiversity and Aquaculture</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400007&lng=en&nrm=iso&tlng=en Recent advances in genomic and post-genomic technologies have now established the new standard in medical and biotechnological research. The introduction of next-generation sequencing, NGS,has resulted in the generation of thousands of genomes from all domains of life, including the genomes of complex uncultured microbial communities revealed through metagenomics. Although the application of genomics to marine biodiversity remains poorly developed overall, some noteworthy progress has been made in recent years. The genomes of various model marine organisms have been published and a few more are underway. In addition, the recent large-scale analysis of marine microbes, along with transcriptomic and proteomic approaches to the study of teleost fishes, mollusks and crustaceans, to mention a few, has provided a better understanding of phenotypic variability and functional genomics. The past few years have also seen advances in applications relevant to marine aquaculture and fisheries. In this review we introduce several examples of recent discoveries and progress made towards engendering genomic resources aimed at enhancing our understanding of marine biodiversity and promoting the development of aquaculture. Finally, we discuss the need for auspicious science policies to address challenges confronting smaller nations in the appropriate oversight of this growing domain as they strive to guarantee food security and conservation of their natural resources. <![CDATA[<strong>Heavy Metal Resistance Strategies of Acidophilic Bacteria and Their Acquisition</strong>: <strong>Importance for Biomining and Bioremediation</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400008&lng=en&nrm=iso&tlng=en Microbial solubilizing of metals in acid environments is successfully used in industrial bioleaching of ores or biomining to extract metals such as copper, gold, uranium and others. This is done mainly by acidophilic and other microorganisms that mobilize metals and generate acid mine drainage or AMD, causing serious environmental problems. However, bioremediation or removal of the toxic metals from contaminated soils can be achieved by using the specific properties of the acidophilic microorganisms interacting with these elements. These bacteria resist high levels of metals by using a few "canonical" systems such as active efflux or trapping of the metal ions by metal chaperones. Nonetheless, gene duplications, the presence of genomic islands, the existence of additional mechanisms such as passive instruments for pH and cation homeostasis in acidophiles and an inorganic polyphosphate-driven metal resistance mechanism have also been proposed. Horizontal gene transfer in environmental microorganisms present in natural ecosystems is considered to be an important mechanism in their adaptive evolution. This process is carried out by different mobile genetic elements, including genomic islands (GI), which increase the adaptability and versatility of the microorganism. This mini-review also describes the possible role of GIs in metal resistance of some environmental microorganisms of importance in biomining and bioremediation of metal polluted environments such as Thiomonas arsenitoxydans, a moderate acidophilic microorganism, Acidithiobacillus caldus and Acidithiobacillus ferrooxidans strains ATCC 23270 and ATCC 53993, all extreme acidophiles able to tolerate exceptionally high levels of heavy metals. Some of these bacteria contain variable numbers of GIs, most of which code for high numbers of genes related to metal resistance. In some cases there is an apparent correlation between the number of metal resistance genes and the metal tolerance of each of these microorganisms. It is expected that a detailed knowledge of the mechanisms that these environmental microorganisms use to adapt to their harsh niche will help to improve biomining and metal bioremediation in industrial processes. <![CDATA[<b>Cyanobacterial defense mechanisms against foreign DNA transfer and their impact on genetic engineering</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400009&lng=en&nrm=iso&tlng=en Cyanobacteria display a large diversity of cellular forms ranging from unicellular to complex multicellular filaments or aggregates. Species in the group present a wide range of metabolic characteristics including the fixation of atmospheric nitrogen, resistance to extreme environments, production of hydrogen, secondary metabolites and exopolysaccharides. These characteristics led to the growing interest in cyanobacteria across the fields of ecology, evolution, cell biology and biotechnology. The number of available cyanobacterial genome sequences has increased considerably in recent years, with more than 140 fully sequenced genomes to date. Genetic engineering of cyanobacteria is widely applied to the model unicellular strains Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942. However the establishment of transformation protocols in many other cyanobacterial strains is challenging. One obstacle to the development of these novel model organisms is that many species have doubling times of 48 h or more, much longer than the bacterial models E. coli or B. subtilis. Furthermore, cyanobacterial defense mechanisms against foreign DNA pose a physical and biochemical barrier to DNA insertion in most strains. Here we review the various barriers to DNA uptake in the context of lateral gene transfer among microbes and the various mechanisms for DNA acquisition within the prokaryotic domain. Understanding the cyanobacterial defense mechanisms is expected to assist in the development and establishment of novel transformation protocols that are specifically suitable for this group. <![CDATA[Synthetic Biology: opportunities for Chilean bioindustry and education]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400010&lng=en&nrm=iso&tlng=en In an age of pressing challenges for sustainable production of energy and food, the new field of Synthetic Biology has emerged as a promising approach to engineer biological systems. Synthetic Biology is formulating the design principles to engineer affordable, scalable, predictable and robust functions in biological systems. In addition to efficient transfer of evolved traits from one organism to another, Synthetic Biology offers a new and radical approach to bottom-up engineering of sensors, actuators, dynamical controllers and the biological chassis they are embedded in. Because it abstracts much of the mechanistic details underlying biological component behavior, Synthetic Biology methods and resources can be readily used by interdisciplinary teams to tackle complex problems. In addition, the advent of robust new methods for the assembly of large genetic circuits enables teaching Biology and Bioengineering in a learning-by-making fashion for diverse backgrounds at the graduate, undergraduate and high school levels. Synthetic Biology offers unique opportunities to empower interdisciplinary training, research and industrial development in Chile for a technology that promises a significant role in this century's economy. <![CDATA[<b>A roadmap to directed enzyme evolution and screening systems for biotechnological applications</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400011&lng=en&nrm=iso&tlng=en Enzymes have been long used in man-made biochemical processes, from brewing and fermentation to current industrial production of fine chemicals. The ever-growing demand for enzymes in increasingly specific applications requires tailoring naturally occurring enzymes to the non-natural conditions found in industrial processes. Relationships between enzyme sequence, structure and activity are far from understood, thus hindering the capacity to design tailored biocatalysts. In the field of protein engineering, directed enzyme evolution is a powerful algorithm to generate and identify novel and improved enzymes through iterative rounds of mutagenesis and screening applying a specific evolutive pressure. In practice, critical checkpoints in directed evolution are: selection of the starting point, generation of the mutant library, development of the screening assay and analysis of the output of the screening campaign. Each step in directed evolution can be performed using conceptually and technically different approaches, all having inherent advantages and challenges. In this article, we present and discuss in a general overview, challenges of designing and performing a directed enzyme evolution campaign, current advances in methods, as well as highlighting some examples of its applications in industrially relevant enzymes. <![CDATA[<b>Nanoparticles and microparticles of polymers and polysaccharides to administer fish vaccines</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400012&lng=en&nrm=iso&tlng=en Aquaculture has become an important economic sector worldwide, but is faced with an ongoing threat from infectious diseases. Vaccination plays a critical role in protecting commercially raised fish from bacterial, viral and parasitic diseases. However, the production of effective vaccines is limited by the scarcity of knowledge about the immune system of fish. Improving vaccines implies using antigens, adjuvants and employing methods of administration that are more effective and less harmful to the fish. In this context, in recent year there have studies of methods of encapsulating antigens in matrices of different types to apply in fish vaccines. This work reviews the new methods to improve fish vaccines by encapsulating them in polymers and polysaccharides. <![CDATA[<strong>Osteogenic molecules for clinical applications</strong>: <strong>improving the BMP-collagen system</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400013&lng=en&nrm=iso&tlng=en Among the osteogenic growth factors used for bone tissue engineering, bone morphogenetic proteins (BMPs) are the most extensively studied for use in orthopaedic surgery. BMP-2 and BMP-7 have been widely investigated for developing therapeutic strategies and are the only two approved for use in several clinical applications. Due to the chemical and biological characteristics of these molecules, their authorised uses are always in combination with a carrier based on collagen type I. Although the use of these growth factors is considered safe in the short term, the very high doses needed to obtain significant osteoinduction make these treatments expensive and their long-term safety uncertain, since they are highly pleiotropic and have the capacity to induce ectopic ossification in the surrounding tissues. Therefore it is necessary to improve the currently used BMP-collagen system in terms of efficiency, biosecurity and costs. There are several strategies to increase the clinical effectiveness of these treatments. In this review we summarize the most promising results and our related work focused on this field through two different approaches: i) the development of recombinant BMPs with additional features, and ii) complementing these systems with other growth factors or molecules to enhance or accelerate osteogenesis <![CDATA[<strong>TAPCells, the Chilean dendritic cell vaccine against melanoma and prostate cancer</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400014&lng=en&nrm=iso&tlng=en Here we summarize 10 years of effort in the development of a biomedical innovation with global projections. This innovation consists of a novel method for the production of therapeutic dendritic-like cells called Tumor Antigen Presenting Cells (TAPCells®). TAPCells-based immunotherapy was tested in more than 120 stage III and IV melanoma patients and 20 castration-resistant prostate cancer patients in a series of phase I and I/II clinical trials. TAPCells vaccines induced T cell-mediated memory immune responses that correlated with increased survival in melanoma patients and prolonged prostate-specific antigen doubling time in prostate cancer patients. Importantly, more than 60% of tested patients showed a Delayed Type Hypersensitivity (DTH) reaction against the lysates, indicating the development of anti-tumor immunological memory that correlates with clinical benefits. The in vitro analysis of the lysate mix showed that it contains damage-associated molecular patterns such as HMBG-1 protein which are capable to improve, through Toll-like receptor-4, maturation and antigen cross-presentation of the dendritic cells (DC). In fact, a Toll-like receptor-4 polymorphism correlates with patient clinical outcomes. Moreover, Concholepas concholepas hemocyanin (CCH) used as adjuvant proved to be safe and capable of enhancing the immunological response. Furthermore, we observed that DC vaccination resulted in a three-fold increase of T helper-1 lymphocytes releasing IFN-γ and a two-fold increase of T helper-17 lymphocytes capable of producing IL-17 in DTH+ with respect to DTH- patients. Important steps have been accomplished for TAPCells technology transfer, including patenting, packaging and technology assessment. Altogether, our results indicate that TAPCells vaccines constitute an exceptional Chilean national innovation of international value. <![CDATA[<strong>Clinical and experimental approaches to knee cartilage lesion repair and mesenchymal stem cell chondrocyte differentiation</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400015&lng=en&nrm=iso&tlng=en Cartilage has poor regeneration capacity due to the scarcity of endogenous stem cells, its low metabolic activity and the avascular environment. Repair strategies vary widely, including microfracture, autologous or allogenic tissue implantation, and in vitro engineered tissues of autologous origin. However, unlike the advances that have been made over more than two decades with more complex organs, including vascular, cardiac or bone tissues, similar advances in tissue engineering for cartilage repair are lacking. Although the inherent characteristics of cartilage tissue, such as the lack of vascularity and low cellular diversity, suggest that it would be one of the more simple tissues to be engineered, its functional weight-bearing role and implant viability and adaptation make this type of repair more complex. Over the last decade several therapeutic approaches and innovative techniques show promise for lasting and functional regeneration of hyaline cartilage. Here we will analyze the main strategies for cartilage regeneration and discuss our experience. <![CDATA[<b>Culture medium composition affects the gene expression pattern and</b> <b><i>in vitro</i></b> <b>development potential of bovine somatic cell nuclear transfer (SCNT) embryos</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000400016&lng=en&nrm=iso&tlng=en Different culture systems have been studied that support development of somatic cell nuclear transfer (SCNT) embryos up to the blastocyst stage. However, the use of sequential and two-step culture systems has been less studied. The objective of the present study was to examine the developmental potential and quality of bovine SCNT embryos cultured in different two-step culture media based on KSOM, SOF and the macromolecules FBS and BSA (K-K/FBS, K-S/BSA and K-K/BSA, respectively). No differences were observed in the cleavage rate for any of the culture systems. However, there was a significant difference (P<0.01) in the rate of blastocyst development, with the K-K/ FBS culture system yielding a higher rate of blastocysts (28%) compared to other treatments (18 and 15%, for K-S/BSA and K-K/BSA, respectively). Although quality of embryos, as assessed by the total number of cells, was not different, the apoptosis index was significantly affected in the sequential culture system (K-S/BSA). Gene expression analysis showed alterations of DNMT1, IGF2, LIF, and PRDX6 genes in embryos cultured in K-S/FBS and of SOD2 in embryos cultured in K-K/BSA. In conclusion, we demonstrated that culture medium may affect not only the developmental potential of SCNT embryos but also, more importantly, the gene expression pattern and apoptotic index, presenting the possibility to manipulate the culture medium composition to modulate global gene expression and improve the overall efficiency of this technique.