Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Foods ; 13(9)2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38731769

RESUMEN

Plant-based proteins have gained popularity in the food industry as a good protein source. Among these, chickpea protein has gained significant attention in recent times due to its high yields, high nutritional content, and health benefits. With an abundance of essential amino acids, particularly lysine, and a highly digestible indispensable amino acid score of 76 (DIAAS), chickpea protein is considered a substitute for animal proteins. However, the application of chickpea protein in food products is limited due to its poor functional properties, such as solubility, water-holding capacity, and emulsifying and gelling properties. To overcome these limitations, various modification methods, including physical, biological, chemical, and a combination of these, have been applied to enhance the functional properties of chickpea protein and expand its applications in healthy food products. Therefore, this review aims to comprehensively examine recent advances in Cicer arietinum (chickpea) protein extraction techniques, characterizing its properties, exploring post-modification strategies, and assessing its diverse applications in the food industry. Moreover, we reviewed the nutritional benefits and sustainability implications, along with addressing regulatory considerations. This review intends to provide insights into maximizing the potential of Cicer arietinum protein in diverse applications while ensuring sustainability and compliance with regulations.

2.
Chemosphere ; 349: 140833, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38043620

RESUMEN

New materials' synthesis and utilization have shown many critical challenges in healthcare and other industrial sectors as most of these materials are directly or indirectly developed from fossil fuel resources. Environmental regulations and sustainability concepts have promoted the use of natural compounds with unique structures and properties that can be biodegradable, biocompatible, and eco-friendly. In this context, nanocellulose (NC) utility in different sectors and industries is reported due to their unique properties including biocompatibility and antimicrobial characteristics. The bacterial nanocellulose (BNC)-based materials have been synthesized by bacterial cells and extracted from plant waste materials including pineapple plant waste biomass. These materials have been utilized in the form of nanofibers and nanocrystals. These materials are found to have excellent surface properties, low density, and good transparency, and are rich in hydroxyl groups for their modifications to other useful products. These materials are well utilized in different sectors including biomedical or health care centres, nanocomposite materials, supercapacitors, and polymer matrix production. This review explores different approaches for NC production from pineapple waste residues using biotechnological interventions, approaches for their modification, and wider applications in different sectors. Recent technological developments in NC production by enzymatic treatment are critically discussed. The utilization of pineapple waste-derived NC from a bioeconomic perspective is summarized in the paper. The chemical composition and properties of nanocellulose extracted from pineapple waste may have unique characteristics compared to other sources. Pineapple waste for nanocellulose production aligns with the principles of sustainability, waste reduction, and innovation, making it a promising and novel approach in the field of nanocellulose materials.


Asunto(s)
Ananas , Nanopartículas , Celulosa/química , Biomasa , Nanopartículas/química , Polímeros
3.
Front Genet ; 14: 1079048, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37007955

RESUMEN

Improved knowledge of the diversity within and among local animal populations is increasingly necessary for their sustainable management. Accordingly, this study assessed the genetic diversity and structure of the indigenous goat population of Benin. Nine hundred and fifty-four goats were sampled across the three vegetation zones of Benin [i.e., Guineo-Congolese zone (GCZ), Guineo-Sudanian zone (GSZ), and Sudanian zone (SZ)] and genotyped with 12 multiplexed microsatellite markers. The genetic diversity and structure of the indigenous goat population of Benin were examined using the usual genetic indices (number of alleles Na, expected and observed heterozygosities He and Ho, Fixation index FST, coefficient of genetic differentiation GST), and three different methods of structure assessment [Bayesian admixture model in STRUCTURE, self-organizing map (SOM), and discriminant analysis of principal components (DAPC)]. The mean values of Na (11.25), He (0.69), Ho (0.66), FST (0.012), and GST (0.012) estimated in the indigenous Beninese goat population highlighted great genetic diversity. STRUCTURE and SOM results showed the existence of two distinct goat groups (Djallonké and Sahelian) with high crossbreeding effects. Furthermore, DAPC distinguished four clusters within the goat population descending from the two ancestry groups. Clusters 1 and 3 (most individuals from GCZ) respectively showed a mean Djallonké ancestry proportion of 73.79% and 71.18%, whereas cluster 4 (mainly of goats from SZ and some goats of GSZ) showed a mean Sahelian ancestry proportion of 78.65%. Cluster 2, which grouped almost all animals from the three zones, was also of Sahelian ancestry but with a high level of interbreeding, as shown by the mean membership proportion of only 62.73%. It is therefore urgent to develop community management programs and selection schemes for the main goat types to ensure the sustainability of goat production in Benin.

4.
Biology (Basel) ; 11(4)2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35453803

RESUMEN

We investigated the changes in genetic diversity over time and space of the cultivated potato (Solanum tuberosum L.) for the period pre-1800 to 2021. A substantial panel of 1219 potato varieties, belonging to different spatiotemporal groups, was examined using a set of 35 microsatellite markers (SSR). Genotypic data covering a total of 407 alleles was analyzed using both self-organizing map (SOM) and discriminant analysis of principal components (DAPC) de novo and a priori clustering methods, respectively. Data analysis based on different models of genetic structuring provided evidence of (1) at least two early lineages that have been maintained since their initial introduction from the Andes into Europe in the 16th century, followed by later ones coming from reintroduction events from the US in the mid-1800s; (2) a level of diversity that has gradually evolved throughout the studied time periods and areas, with the most modern variety groups encompassing most of the diversity found in earlier decades; (3) the emergence of new genetic groups within the current population due to increases in the use of germplasm enhancement practices using exotic germplasms. In addition, analysis revealed significant genetic differentiation both among and within the spatiotemporal groups of germplasm studied. Our results therefore highlight that no major genetic narrowing events have occurred within the cultivated potato over the past three centuries. On the contrary, the genetic base shows promising signs of improvement, thanks to extensive breeding work that is gaining momentum. This overview could be drawn on not only to understand better how past decisions have impacted the current genetic cultivated potato resources, but also to develop appropriate new strategies for breeding programs consistent with the socio-economic and sustainability challenges faced by agrifood systems.

5.
PLoS One ; 16(10): e0258761, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34665825

RESUMEN

Knowledge of both the genetic diversity and geographical distribution of animal genetic resources is a prerequisite for their sustainable utilization, improvement and conservation. The present study was undertaken to explore the current morphological variability within the sheep population in Benin as a prelude for their molecular characterization. From November 2018 to February 2020, 25 quantitative linear body measurements and 5 qualitative physical traits were recorded on 1240 adult ewes from the 10 phytogeographic zones that comprise the three vegetation zones of Benin. Fourteen morphological indices were calculated based on the linear body measurements. The collected data were first analyzed using multiple comparisons of least-square means (LSmeans), followed by generalized linear model (GLM) procedures, to explore the relationships among the measured morphometric traits and the 10 phytogeographic zones. Next, the presence of any genetic sub-populations was examined using multivariate analytical methods, including canonical discriminant analysis (CDA) and ascending hierarchical clustering (AHC). Univariate analyses indicated that all quantitative linear body measurements varied significantly (P<0.05) across the phytogeographic zones. The highest values (LSmean± standard error) of withers height (68.3±0.47 cm), sternum height (46.0±0.35 cm), and rump height (68.8±0.47 cm) were recorded in the Mekrou-Pendjari zone, the drier phytogeographic zone in the North, whereas the lowest values, 49.2±0.34, 25.9±0.26, and 52.0±0.35 cm, respectively, were recorded in the Pobe zone in the South. Multivariate analyses revealed the prevalence of four distinct sheep sub-populations in Benin. The sub-population from the South could be assimilated to the short-legged and that from the North to the West African long-legged sheep. The two other sub-populations were intermediate and closer to the crossbreeds or another short-legged sub-breed. The proportion of individuals correctly classified in their group of origin was approximately 74%. These results uncovered a spatial morphological variation in the Beninese sheep population along a South-North phytogeographic gradient.


Asunto(s)
Ovinos/anatomía & histología , Ovinos/clasificación , Animales , Benin , Biometría , Demografía , Análisis Discriminante , Hibridación Genética , Modelos Lineales , Análisis Multivariante , Fenotipo , Filogenia
6.
Planta Med ; 87(10-11): 868-878, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34237787

RESUMEN

Translesion synthesis is a DNA damage tolerance mechanism that relies on a series of specialized DNA polymerases able to bypass a lesion on a DNA template strand during replication or post-repair synthesis. Specialized translesion synthesis DNA polymerases pursue replication by inserting a base opposite to this lesion, correctly or incorrectly depending on the lesion nature, involved DNA polymerase(s), sequence context, and still unknown factors. To measure the correct or mutagenic outcome of 8-oxo-7,8-dihydro-2'-deoxyguanosine bypass by translesion synthesis, a primer-extension assay was performed in vitro on a template DNA bearing this lesion in the presence of nuclear proteins extracted from human intestinal epithelial cells (FHs 74 Int cell line); the reaction products were analyzed by both denaturing capillary electrophoresis (to measure the yield of translesion elongation) and pyrosequencing (to determine the identity of the nucleotide inserted in front of the lesion). The influence of 14 natural polyphenols on the correct or mutagenic outcome of translesion synthesis through 8-oxo-7,8-dihydro-2'-deoxyguanosine was then evaluated in 2 experimental conditions by adding the polyphenol either (i) to the reaction mix during the primer extension assay; or (ii) to the culture medium, 24 h before cell harvest and nuclear proteins extraction. Most of the tested polyphenols significantly influenced the outcome of translesion synthesis, either through an error-free (apigenin, baicalein, sakuranetin, and myricetin) or a mutagenic pathway (epicatechin, chalcone, genistein, magnolol, and honokiol).


Asunto(s)
ADN Polimerasa Dirigida por ADN , Desoxiguanosina , 8-Hidroxi-2'-Desoxicoguanosina , ADN , Replicación del ADN , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Humanos
7.
Food Microbiol ; 62: 133-140, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27889139

RESUMEN

The beneficial contributions of Kazachstania servazzii are well-established in various food processes. This yeast also contributes in the spoilage of finished packaged food due to abundant gas production. In particular, an occurrence of K. servazzii was recently positively correlated with the formation of severe package swelling of some prepared fresh pizzas. To circumscribe this concern, a quantitative SYBR green real-time PCR assay based on a newly designed specific primer pair targeting the ribosomal ITS1-5.8S-ITS2 region of K. servazzii was developed. The quantification was enabled using a standard curve created from serially diluted plasmids containing the target sequence of the K. servazzii strain. A validation of the assay was achieved by enumeration of K. servazzii DNA copies from artificially infected culture broths containing non-contaminated pizza substrates. The newly developed method was then tested on total DNA extracted from packaged fresh pizzas, in which certain lots were swollen and thus suspected of containing K. servazzii. This study highlights that this newly developed quantitative assay is not only sufficiently sensitive, specific and reliable to be functionally used in food control as a routine method of detection, but also promising in specific studies that seek to further characterize the dynamic of this yeast in some increasingly popular food processes.


Asunto(s)
Microbiología de Alimentos/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Saccharomycetales/aislamiento & purificación , Cartilla de ADN , Medición de Riesgo , Saccharomyces cerevisiae/genética , Saccharomycetales/genética , Especificidad de la Especie
8.
PeerJ ; 4: e1786, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26989623

RESUMEN

Phenotypic variations allow a lineage to move into new regions of the adaptive landscape. The purpose of this study is to analyse the life history of the pearlfishes (Carapinae) in a phylogenetic framework and particularly to highlight the evolution of parasite and commensal ways of life. Furthermore, we investigate the skull anatomy of parasites and commensals and discuss the developmental process that would explain the passage from one form to the other. The genus Carapus forms a paraphyletic grouping in contrast to the genus Encheliophis, which forms a monophyletic cluster. The combination of phylogenetic, morphologic and ontogenetic data clearly indicates that parasitic species derive from commensal species and do not constitute an iterative evolution from free-living forms. Although the head morphology of Carapus species differs completely from Encheliophis, C. homei is the sister group of the parasites. Interestingly, morphological characteristics allowing the establishment of the relation between Carapus homei and Encheliophis spp. concern the sound-producing mechanism, which can explain the diversification of the taxon but not the acquisition of the parasite morphotype. Carapus homei already has the sound-producing mechanism typically found in the parasite form but still has a commensal way of life and the corresponding head structure. Moreover, comparisons between the larval and adult Carapini highlight that the adult morphotype "Encheliophis" is obtained by going beyond the adult stage reached by Carapus. The entrance into the new adaptive landscape could have been realised by at least two processes: paedomorphosis and allometric repatterning.

9.
Mol Phylogenet Evol ; 66(1): 161-81, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23063883

RESUMEN

Although the status of Crinoidea (sea lilies and featherstars) as sister group to all other living echinoderms is well-established, relationships among crinoids, particularly extant forms, are debated. All living species are currently placed in Articulata, which is generally accepted as the only crinoid group to survive the Permian-Triassic extinction event. Recent classifications have recognized five major extant taxa: Isocrinida, Hyocrinida, Bourgueticrinina, Comatulidina and Cyrtocrinida, plus several smaller groups with uncertain taxonomic status, e.g., Guillecrinus, Proisocrinus and Caledonicrinus. Here we infer the phylogeny of extant Crinoidea using three mitochondrial genes and two nuclear genes from 59 crinoid terminals that span the majority of extant crinoid diversity. Although there is poor support for some of the more basal nodes, and some tree topologies varied with the data used and mode of analysis, we obtain several robust results. Cyrtocrinida, Hyocrinida, Isocrinida are all recovered as clades, but two stalked crinoid groups, Bourgueticrinina and Guillecrinina, nest among the featherstars, lending support to an argument that they are paedomorphic forms. Hence, they are reduced to families within Comatulida. Proisocrinus is clearly shown to be part of Isocrinida, and Caledonicrinus may not be a bourgueticrinid. Among comatulids, tree topologies show little congruence with current taxonomy, indicating that much systematic revision is required. Relaxed molecular clock analyses with eight fossil calibration points recover Articulata with a median date to the most recent common ancestor at 231-252mya in the Middle to Upper Triassic. These analyses tend to support the hypothesis that the group is a radiation from a small clade that passed through the Permian-Triassic extinction event rather than several lineages that survived. Our tree topologies show various scenarios for the evolution of stalks and cirri in Articulata, so it is clear that further data and taxon sampling are needed to recover a more robust phylogeny of the group.


Asunto(s)
Evolución Biológica , Equinodermos/clasificación , Filogenia , Animales , Teorema de Bayes , Núcleo Celular/genética , ADN Mitocondrial/genética , Equinodermos/genética , Fósiles , Funciones de Verosimilitud , Alineación de Secuencia , Análisis de Secuencia de ADN
10.
Biol Bull ; 223(2): 217-25, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23111133

RESUMEN

The shelter of the tube-dwelling polychaete Sabellaria alveolata is composed of mineral particles assembled with spots of a proteinaceous cement. The adhesive proteins constituting the cement were identified on the basis of their sequence similarity with proteins of a phylogenetically related species, Phragmatopoma californica. Two positively charged proteins, Sa-1 and Sa-2, share common features: they both have a mass of 22 kDa; are rich in glycine, tyrosine and basic residues; and show repeated peptide motifs. The consensus repeat of Sa-1 is KGAYGAKGLGYGNKAGYGAYG (occurring 6-8 times), while Sa-2 displays the consensus heptapeptide VHKAAWG (5 times) and undecapeptide VHKAAGYGGYG (8 times). Two variants of a serine-rich protein, Sa-3A (22 kDa) and Sa-3B (21 kDa), were also identified. Their serine residues account for 75 mol% and are probably phosphorylated, meaning that Sa-3 is very acidic and negatively charged. Moreover, tyrosine residues of all adhesive proteins are presumably modified into DOPA. Although protein sequences are not well-conserved between S. alveolata and P. californica, their main characteristics (including amino acid composition, post-translational modifications, repeated patterns, isoelectric point, and mass) are shared by both species. This suggests that these features are more important for their function than the primary structure of the proteins. The mRNA abundance for each protein was estimated by quantitative real-time PCR, revealing relative expression levels of about 5, 11, 1.5, and 1 for Sa-1, -2, -3A, and -3B, respectively. These levels could be indicative of charge neutralization phenomena or could reflect their function (interface vs. bulk) in the cement.


Asunto(s)
Poliquetos/genética , Poliquetos/metabolismo , Proteínas/genética , Proteínas/metabolismo , Adhesivos Tisulares/metabolismo , Aminoácidos/análisis , Animales , Perfilación de la Expresión Génica , Datos de Secuencia Molecular , Peso Molecular , Proteínas/química , Reacción en Cadena en Tiempo Real de la Polimerasa , Secuencias Repetitivas de Aminoácido , Análisis de Secuencia de ADN , Adhesivos Tisulares/química
11.
BMC Evol Biol ; 11: 365, 2011 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-22182416

RESUMEN

BACKGROUND: Clownfishes are colorful coral reef fishes living in groups in association with sea anemones throughout the Indo-Pacific Ocean. Within their small societies, size hierarchy determines which fish have access to reproduction. These fishes are also prolific callers whose aggressive sounds seem to play an important role in the social hierarchy. Agonistic interactions being involved in daily behaviour suggest how acoustic communication might play an important role in clownfish group. Sounds were recorded and compared in fourteen clownfish species (some of which have never been recorded before) to evaluate the potential role of acoustic communication as an evolutionary driving force. RESULTS: Surprisingly, the relationship between fish size and both dominant frequency and pulse duration is not only species-specific; all the specimens of the 14 species are situated on exactly the same slope, which means the size of any Amphiprion can be predicted by both acoustic features. The number of pulses broadly overlaps among species, whereas the pulse period displays the most variation even if it shows overlap among sympatric species. Sound comparisons between three species (A. akallopisos, A. ocellaris and A. frenatus) having different types of teeth and body shape do not show differences neither in the acoustic waveform nor in the power spectrum. CONCLUSION: Significant overlap in acoustic features demonstrates that the sound-producing mechanism is highly conservative among species. Differences in the calls of some species are due to size dimorphism and the sound variation might be in this case a by-product. This morphological constraint does not permit a consideration of acoustic communication as the main driving force in the diversification of clownfishes. Moreover, calls are not produced to find mate and consequently are less subject to variations due to partner preference, which restricts the constraints of diversification. Calls are produced to reach and defend the competition to mate access. However, differences in the pulse period between cohabiting species show that, in some case, sounds can help to differentiate the species, to prevent competition between cohabiting species and to promote the diversification of taxa.


Asunto(s)
Acústica , Evolución Biológica , Perciformes/fisiología , Vocalización Animal , Animales , Tamaño Corporal , Perciformes/anatomía & histología , Especificidad de la Especie
12.
J Hered ; 101(6): 663-75, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20538757

RESUMEN

We studied patterns of genetic diversity within and among 5 populations (318 individuals) of Galápagos marine iguanas (Amblyrhynchus cristatus) from the island Santa Fé. Populations were separated by distances of 0.2 to 9.9 km. We sequenced 1182 base pairs of the mitochondrial control region and screened 13 microsatellite loci for variability. We also added data from 5 populations (397 individuals) sampled on 4 neighboring islands (Santa Cruz, Floreana, Espanola, and San Cristobal). The 5 Santa Fé populations, revealed as genetically distinct from populations on other islands, present relatively low levels of genetic diversity, which are similar for both microsatellite (average observed heterozygosity from 0.7686 to 0.7773) and mitochondrial DNA (mtDNA) markers (haplotypic and nucleotide diversity from 0.587 to 0.728 and from 0.00079 to 0.00293, respectively), and comparable with those observed in similar-sized sampling sites on other islands. There was frequency-based evidence of genetic structure between northern and southern sites on Santa Fé (F(st) of 0.0027-0.0115 for microsatellite and 0.0447-0.2391 for mtDNA), but the 4 southern sites showed little differentiation. Most of the intra-island genetic variation was allocated within rather than between sites. There was no evidence of sex-biased dispersal or population substructuring due to lek-mating behavior, suggesting that these 2 observed behaviors are not strong enough to leave an evolutionary signal on genetic patterns in this species.


Asunto(s)
ADN Mitocondrial/genética , Flujo Genético , Variación Genética , Iguanas/genética , Animales , Organismos Acuáticos/genética , Secuencia de Bases , Cruzamiento , Ecuador , Evolución Molecular , Femenino , Flujo Génico , Haplotipos , Masculino , Repeticiones de Microsatélite/genética , Mitocondrias , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa
13.
Mol Phylogenet Evol ; 54(2): 357-71, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19686859

RESUMEN

Although molecular-based phylogenetic studies of hosts and their associates are increasingly common in the literature, no study to date has examined the hypothesis of coevolutionary process between hosts and commensals in the marine environment. The present work investigates the phylogenetic relationships among 16 species of obligate symbiont marine worms (Myzostomida) and their echinoderm hosts (Crinoidea) in order to estimate the phylogenetic congruence existing between the two lineages. The combination of a high species diversity in myzostomids, their host specificity, their wide variety of lifestyles and body shapes, and millions years of association, raises many questions about the underlying mechanisms triggering their diversification. The phylogenetic relationships, inferred using a three-genes dataset (18S rDNA, 16S rDNA, and COI) and two-genes dataset (18S rDNA, and COI) for the myzostomids and crinoids, respectively, were congruent with the literature. The overall congruence between the two phylogenies was statistically significant according to topology-based, distance-based, and data-based approaches: a significant pattern of cophylogeny was found, though not perfect probably resulting from occasional host switches, duplications or extinction events. A minimum of 8 cospeciation events was estimated, which is significantly higher than it would have been expected due to chance alone.


Asunto(s)
Anélidos/genética , Equinodermos/genética , Evolución Molecular , Especiación Genética , Filogenia , Simbiosis/genética , Animales , Anélidos/clasificación , ADN Mitocondrial/genética , ADN Ribosómico/genética , Equinodermos/clasificación , Alineación de Secuencia , Análisis de Secuencia de ADN
14.
BMC Evol Biol ; 9: 297, 2009 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-20028547

RESUMEN

BACKGROUND: Marine iguanas (Amblyrhynchus cristatus) inhabit the coastlines of large and small islands throughout the Galápagos archipelago, providing a rich system to study the spatial and temporal factors influencing the phylogeographic distribution and population structure of a species. Here, we analyze the microevolution of marine iguanas using the complete mitochondrial control region (CR) as well as 13 microsatellite loci representing more than 1200 individuals from 13 islands. RESULTS: CR data show that marine iguanas occupy three general clades: one that is widely distributed across the northern archipelago, and likely spread from east to west by way of the South Equatorial current, a second that is found mostly on the older eastern and central islands, and a third that is limited to the younger northern and western islands. Generally, the CR haplotype distribution pattern supports the colonization of the archipelago from the older, eastern islands to the younger, western islands. However, there are also signatures of recurrent, historical gene flow between islands after population establishment. Bayesian cluster analysis of microsatellite genotypes indicates the existence of twenty distinct genetic clusters generally following a one-cluster-per-island pattern. However, two well-differentiated clusters were found on the easternmost island of San Cristóbal, while nine distinct and highly intermixed clusters were found on youngest, westernmost islands of Isabela and Fernandina. High mtDNA and microsatellite genetic diversity were observed for populations on Isabela and Fernandina that may be the result of a recent population expansion and founder events from multiple sources. CONCLUSIONS: While a past genetic study based on pure FST analysis suggested that marine iguana populations display high levels of nuclear (but not mitochondrial) gene flow due to male-biased dispersal, the results of our sex-biased dispersal tests and the finding of strong genetic differentiation between islands do not support this view. Therefore, our study is a nice example of how recently developed analytical tools such as Bayesian clustering analysis and DNA sequence-based demographic analyses can overcome potential biases introduced by simply relying on FST estimates from markers with different inheritance patterns.


Asunto(s)
Flujo Génico , Iguanas/genética , Animales , Núcleo Celular/genética , ADN Mitocondrial/genética , Ecuador , Femenino , Variación Genética , Genética de Población , Región de Control de Posición , Masculino , Repeticiones de Microsatélite
15.
Dev Genes Evol ; 219(4): 211-6, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19319567

RESUMEN

Using degenerate primers, we were able to identify seven Hox genes for the myzostomid Myzostoma cirriferum. The recovered fragments belong to anterior class (Mci_lab, Mci_pb), central class (Mci_Dfd, Mci_Lox5, Mci_Antp, Mci_Lox4), and posterior class (Mci_Post2) paralog groups. Orthology assignment was verified by phylogenetic analyses and presence of diagnostic regions in the homeodomain as well as flanking regions. The presence of Lox5, Lox4, and Post2 supports the inclusion of Myzostomida within Lophotrochozoa. We found signature residues within flanking regions of Lox5, which are also found in annelids, but not in Platyhelminthes. As such the available Hox genes data of myzostomids support an annelid relationship.


Asunto(s)
Anélidos/genética , Genes Homeobox , Secuencia de Aminoácidos , Animales , Anélidos/clasificación , Proteína con Homeodominio Antennapedia/química , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , Alineación de Secuencia
16.
PLoS One ; 2(12): e1285, 2007 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-18074011

RESUMEN

The El Niño-Southern Oscillation (ENSO) is a major source of climatic disturbance, impacting the dynamics of ecosystems worldwide. Recent models predict that human-generated rises in green-house gas levels will cause an increase in the strength and frequency of El Niño warming events in the next several decades, highlighting the need to understand the potential biological consequences of increased ENSO activity. Studies have focused on the ecological and demographic implications of El Niño in a range of organisms, but there have been few systematic attempts to measure the impact of these processes on genetic diversity in populations. Here, we evaluate whether the 1997-1998 El Niño altered the genetic composition of Galápagos marine iguana populations from eleven islands, some of which experienced mortality rates of up to 90% as a result of El Niño warming. Specifically, we measured the temporal variation in microsatellite allele frequencies and mitochondrial DNA diversity (mtDNA) in samples collected before (1991/1993) and after (2004) the El Niño event. Based on microsatellite data, only one island (Marchena) showed signatures of a genetic bottleneck, where the harmonic mean of the effective population size (N(e)) was estimated to be less than 50 individuals during the period between samplings. Substantial decreases in mtDNA variation between time points were observed in populations from just two islands (Marchena and Genovesa). Our results suggests that, for the majority of islands, a single, intense El Niño event did not reduce marine iguana populations to the point where substantial neutral genetic diversity was lost. In the case of Marchena, simultaneous changes to both nuclear and mitochondrial DNA variation may also be the result of a volcanic eruption on the island in 1991. Therefore, studies that seek to evaluate the genetic impact of El Niño must also consider the confounding or potentially synergistic effect of other environmental and biological forces shaping populations.


Asunto(s)
Iguanas/genética , Tiempo (Meteorología) , Animales , Secuencia de Bases , Cartilla de ADN , Estudios de Factibilidad , Repeticiones de Microsatélite/genética
17.
Syst Biol ; 55(2): 208-27, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16537291

RESUMEN

The fossil record indicates that Myzostomida, an enigmatic group of marine worms, traditionally considered as annelids, have exhibited a symbiotic relationship with echinoderms, especially crinoids, for nearly 350 million years. All known extant myzostomids are associated with echinoderms and infest their integument, gonads, celom, or digestive system. Using nuclear (18S rDNA) and mitochondrial (16S and COI) DNA sequence data from 37 myzostomid species representing nine genera, we report here the first molecular phylogeny of the Myzostomida and investigate the evolution of their various symbiotic associations. Our analyses indicate that the two orders Proboscidea and Pharyngidea do not constitute natural groupings. Character reconstruction analyses strongly suggest that (1) the ancestor of all extant myzostomids was an ectocommensal that first infested crinoids, and then asteroids and ophiuroids, and (2) parasitism in myzostomids emerged multiple times independently.


Asunto(s)
Anélidos/genética , Anélidos/fisiología , Equinodermos/parasitología , Evolución Molecular , Filogenia , Simbiosis , Animales , Anélidos/ultraestructura , Interacciones Huésped-Parásitos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...