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Detection of Vibrio campbellii and V. parahaemolyticus carrying full-length pirABVp but only V. campbellii produces PirVp toxins
No full textAcute hepatopancreatic necrosis disease (AHPND) is a newly emerging disease of penaeid shrimps caused by a unique strain of Vibrio species that carries a plasmid harboring PirABVp-binary toxin gene. Since the first outbreak in 2009, the diseases have been reported in a number of countries in Asia, America, and Latin America. In the present study, we obtained 51 bacterial isolates recovered from five AHPND suspected shrimp farms in South America for PCR diagnosis using AP4 nested PCR method. There were 3/51 isolates (34, 36 and 43) from two farms which tested positive by AP4 primers targeting PirABVp toxin genes. The detection results were also confirmed by duplex pirABVp PCR assay. Subsequently, integrity of full length pirABVp genes in the three positive isolates was revealed by sequencing analysis. Bacterial species identification by ldh-specific PCR combined with multilocus sequencing analysis (MLSA) revealed that the two isolates 36 and 43 are V. parahaemolyticus while the isolate 34 is V. campbellii. Surprisingly, pirABVp mRNA transcript was detected from only V. campbellii 34 while that of V. parahaemolyticus 36 and 43 were undetectable. The results coincide with Western blot analysis that only V. campbellii 34 produces both PirAVp and PirBVp toxins while two isolates of V. parahaemolyticus pirAVp+ and pirBVp+ express neither PirAVp nor PirBVp toxins. Experimental challenge revealed that PirABVp-containing V. campbellii 34 and atypical V. parahaemolyticus isolates 36 and 43 were pathogenic to shrimp. Massive cell sloughing of hepatopancreatic tubule epithelial cells, characteristic of AHPND, was observed from shrimp exposed to isolate 34 while isolates 36 and 43 caused extensive collapsed hepatopancreatic tubule epithelia. The findings in this study indicated that there is a proportion of Vibrio isolates harboring intact pirABVp that were tested positive by PCR but did not produce AHPND PirABVp toxins. We thus suggested that investigation of pirABVp expression at transcriptional and translational levels as well as bioassay is required for confirmation of AHPND-causing Vibrio strain.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Fibrinogen-clotting enzyme, pictobin, from Bothrops pictus snake venom. Structural and functional characterization
No full textA thrombin-like enzyme, pictobin, was purified from Bothrops pictus snake venom. It is a 41-kDa monomeric glycoprotein as showed by mass spectrometry and contains approx. 45% carbohydrate by mass which could be removed with N-glycosidase. Pictobin coagulates plasma and fibrinogen, releasing fibrinopeptide A and induces the formation of a friableiporous fibrin network as visualized by SEM. The enzyme promoted platelet aggregation in human PRP and defibrination in mouse model and showed catalytic activity on chromogenic substrates S-2266, S-2366, S-2160 and S-2238. Pictobin interacts with the plasma inhibitor alpha 2-macroglobulin, which blocks its interaction with fibrinogen but not with the small substrate BApNA. Heparin does not affect its enzymatic activity. Pictobin cross reacted with polyvalent bothropic antivenom, and its deglycosylated form reduced its catalytic action and antivenom reaction. In breast and lung cancer cells, pictobin inhibits the fibronectin-stimulated migration. Moreover, it produces strong NADH oxidation, mitochondrial depolarization, ATP decrease and fragmentation of mitochondria! network. These results suggest by first time that a snake venom serinprotease produces mitochondrial dysfunction by affecting mitochondrial dynamics and bioenergetics. Structural model of pictobin reveals a conserved chymotrypsin fold beta/beta hydrolase. These data indicate that pictobin has therapeutic potential in the treatment of cardiovascular disorders and metastatic disease.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Phytochemical screening and DPPH radical scavenging activity of three morphotypes of Mauritia flexuosa L.f. from Peru, and thermal stability of a milk-based beverage enriched with carotenoids from these fruits
No full textMauritia flexuosa L.f. is a palm tree which presents great morphological variability (morphotypes), represented mainly by the mesocarp color of its fruits. The objective of the study was to characterize the physicochemical and antioxidant properties of three morphotypes of Mauritia flexuosa L.f. (Yellow, Colour and Shambo) of greater economic importance in the Peruvian Amazon. Shambo showed a significantly high content of bioactive compounds (total phenolics, flavonoids and carotenoids) and DPPH radical scavenging activity compared to the Yellow and Colour morphotypes (p <= 0.05). There was a significant correlation between DPPH radical scavenging activity and total phenolics, flavonoids and carotenoids (p <= 0.01). Furthermore, milk-based beverages enriched with carotenoids of those morphotypes of Mauritia flexuosa L.f. have been shown to be a good source of bioactive compounds for use in the food industry. The milk-based beverages enriched with carotenoids of those morphotypes of Mauritia flexuosa L.f. showed higher lightness (L*) and yellowness (b*).Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
CRISPR-Cas13d Induces Efficient mRNA Knockdown in Animal Embryos
No full textEarly embryonic development is driven exclusively by maternal gene products deposited into the oocyte. Although critical in establishing early developmental programs, maternal gene functions have remained elusive due to a paucity of techniques for their systematic disruption and assessment. CRISPR-Cas13 systems have recently been employed to degrade RNA in yeast, plants, and mammalian cell lines. However, no systematic study of the potential of Cas13 has been carried out in an animal system. Here, we show that CRISPR-RfxCas13d (CasRx) is an effective and precise system to deplete specific mRNA transcripts in zebrafish embryos. We demonstrate that zygotically expressed and maternally provided transcripts are efficiently targeted, resulting in a 76% average decrease in transcript levels and recapitulation of well-known embryonic phenotypes. Moreover, we show that this system can be used in medaka, killifish, and mouse embryos. Altogether, our results demonstrate that CRISPR-RfxCas13d is an efficient knockdown platform to interrogate gene function in animal embryos.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Assessment of the mechanical properties of peruvian Stipa Obtusa fibers for their use as reinforcement in composite materials
No full textThis paper presents the study of the mechanical properties of technical fibers extracted from the Stipa Obtusa grass considering three different alkali treatment times, 1.5, 3 and 5 h; additionally, fiber/matrix compatibility is evaluated via the single fiber fragmentation test, and the best treatment in terms of mechanical properties and compatibility is used to test the effect of gage length, strain rate and cyclic deformation. Result shows that mechanical properties increase with treatment time until a maximum (strength similar to 569 MPa, modulus similar to 28 GPa and strain 0.026), and afterwards decreases; furthermore, strength and strain decreases as the fiber length increases; while, the strain rate's effect is negligible unless at very low speed, and a cyclic deformation leads to an increase of the modulus (similar to 13%). It can be concluded that fibers extracted from the Stipa Obtusa show potential and can compete with commercial natural fibers as a reinforcement in polymeric matrix composites.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
The Role of Feral Goats in Maintaining Firebreaks by Using Attractants
No full textThe threat of large forest fires is increasing, and the main causes are the depopulation of rural areas, along with the effects of climate change. To counter this threat in recent decades, there have been numerous proposals and actions aimed at promoting grazing in the forest as a tool for controlling biomass fuel. However, the continued disappearance of traditional herds makes this activity difficult. Rural depopulation has also meant that domestic species become feral, being habitual in the case of goats. Currently, little is known about the role that feral goats can play in the fight against forest fires. In this work, an analysis is made on the effect of feral goats on the control of the vegetation in firebreak areas. Furthermore, the effect of attractants, such as water, salt, or food, on goat behavior is also studied. The study was carried out on the island of Mallorca, where a population of feral goats occupies the mountain areas, and where it is common for them to graze on the network of firebreaks. The results showed that these areas in themselves exert an attractive effect with respect to the neighboring forest, and that the herbaceous biomass is reduced. This effect was enhanced with the implementation of water and salt points, although only in certain periods of the year. In general, it was possible to reduce the phytovolume of many species without affecting biodiversity in the short or medium term. Therefore, strategic management of feral animals, aimed at firebreak areas, could contribute not only to reducing the risk of fires and, consequently, to the mitigation of climate change, but also to attracting these animals to the forests, thus avoiding their dispersion to conflictive places such as roads, residences, agricultural fields, and gardens.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Taxonomic revision of the Menticirrhus americanus (Linnaeus, 1758) and M. littoralis (Holbrook, 1847) (Percomorphacea: Sciaenidae) species complexes from the western Atlantic
No full textThe genus Menticirrhus is widely distributed in the Neotropical region, where its species are common and abundant in shallow coastal waters and estuaries. The diversity, biogeography, and evolutionary relationships of the Menticirrhus species are still poorly known, due primarily to the difficulty of differentiating the species, given the broad similarities in their external morphology. The present study is based on the analysis of morphological and molecular data, with the examination of type specimens and a comprehensive collection of non-type specimens from an ample geographic range. These analyses indicated that two widely distributed Western Atlantic species, Menticirrhus americanus and M. littoralis, represent species complexes. The M. littoralis species complex is characterized by the absence of dark bars on body side, and a smaller, light-colored pectoral fins, that barely reaching the tip of the depressed pelvic fins, with fewer pectoral-fin rays. This complex includes three species: M. littoralis, found in the Gulf of Mexico, M. gracilis, from the southeastern and southern coast of South America, and a new species, described here, from the northern to eastern Brazilian coast. The M. americanus species complex is characterized by the presence of dark bars on body side, and a large, dark pectoral fin, that surpass the tip of the depressed pelvic fin, with more pectoral-fin rays. This complex has two species, M. americanus, which occurs on the east coast of the United States and in the Gulf of Mexico, and M. martinicensis, found from Caribbean to Argentina, that represents a cryptic allopatric species. An identification key to all species of the genus is presented.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Nutritional evaluation and human health-promoting potential of compounds biosynthesized by native microalgae from the Peruvian Amazon
No full textA plausible strategy to mitigate socioeconomic problems in the Peruvian Amazon is through the sustainable exploitation of biodiversity resources, such as native microalgae. Several studies worldwide affirm that these microorganisms are excellent sources of higher value products for human nutrition and possess health-promoting biochemicals, but these attributes are unknown for the native microalgae of Peru. Therefore, the aim of this investigation was to evaluate the nutritional and human health-promoting potential of compounds biosynthesized by native microalgae from the Peruvian Amazon. Ten native microalgae strains of the groups cyanobacteria and chlorophyta were cultured in BG-11 medium and their biomass harvested and dried. Standardized methods were then used to determine proximate composition, fatty acids and amino acids composition, antioxidant activity, and total phenolic content. All ten microalgae strains produce primary nutrients, the entire spectrum of essential amino acids, essential fatty acids, and 3 of the 10 microalgae strains produced eisosapentaenoic acid. Additionally, all microalgae strains exhibited antioxidant activities and contained phenolic compounds. In conclusion, native microalgae strains from the Peruvian Amazon analyzed in this study possess the ability to biosynthesize and accumulate several nutrients and compounds with human health-promoting potential.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Coherence-based measurement of non-Markovian dynamics in an open quantum system
No full textWe present a theoretical scheme and its experimental proof of principle for an open quantum system undergoing Markovian and non-Markovian evolutions. We exhibit these two regimes by diagnosing them with the relative entropy of coherence of two polarization qubits playing the roles of system and ancilla. These are initially prepared in a polarization maximally entangled state of a photon pair produced by spontaneous parametric down-conversion. We induce Markovian and non-Markovian regimes in the system's dynamics with the help of two auxiliary qubits, experimentally implemented by optical paths in a layout of Sagnac and Mach-Zehnder interferometers. We replicate system-environment interactions by means of an amplitude damping channel and a suitably designed inversion of it. In our scheme, one needs only two experimentally accessible parameters to achieve Markovian and non-Markovian regimes.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Mygalin: An Acylpolyamine With Bactericidal Activity
No full textInappropriate use of antibiotics favors the selection and spread of resistant bacteria. To reduce the spread of these bacteria, finding new molecules with activity is urgent and necessary. Several polyamine analogs have been constructed and used to control microorganisms and tumor cells. Mygalin is a synthetic acylpolyamine, which are analogs of spermidine, derived from the hemolymph of the spider Acanthoscurria gomesiana. The effective activity of polyamines and their analogs has been associated with their structure. The presence of two acyl groups in the Mygalin structure may give this molecule a specific antibacterial activity. The aim of this study was to identify the mechanisms involved in the interaction of Mygalin with Escherichia coli to clarify its antimicrobial action. The results indicated that Mygalin exhibits intense dose and time-dependent bactericidal activity. Treatment of E. coli with this molecule caused membrane rupture, inhibition of DNA synthesis, DNA damage, and morphological changes. The esterase activity increased along with the intracellular production of reactive oxygen species (ROS) after treatment of the bacteria with Mygalin. In addition, this molecule was able to sequester iron and bind to LPS. We have shown that Mygalin has bactericidal activity with underlying mechanisms involving ROS generation and chelation of iron ions that are necessary for bacterial metabolism, which may contribute to its microbicidal activity. Taken together, our data suggest that Mygalin can be explored as a new alternative drug with antimicrobial potential against Gram-negative bacteria or other infectious agents.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy