155 research outputs found
On the role of the proventricle region in reproduction and regeneration in Typosyllis antoni (Annelida: Syllidae)
Background: Syllids are a species rich annelid family possessing remarkable regenerative ability, which is not only the response after traumatic injury, but also a key step during the life cycle of several syllid taxa. In these animals the posterior part of the body becomes an epitoke and is later detached as a distinct unit named stolon. Such a
sexual reproductive mode is named schizogamy or stolonization. The prostomium and the proventricle, a modified foregut structure, have been proposed to have a control function during this process, though the concrete mechanisms behind it have never been elucidated. Results: By using different experimental set-ups, histology and immunohistochemistry combined with subsequent cLSM analyzes, we investigate and document the regeneration and stolonization in specimens of Typosyllis antoni that were amputated at different levels throughout the antero-posterior body axis. The removal of the anterior end including the proventricle implies an incomplete anterior regeneration as well as severe deviations from the usual reproductive pattern, i.e. accelerated stolonization, masculinization and the occurrence of aberrant stolons. The detailed anatomy of aberrant
stolons is described. A histological study of the proventricle revealed no signs of glandular or secretory structures. The ventricle and the caeca are composed of glandular tissue but they are not involved in the reproductive and regenerative processes. Conclusions: As in other investigated syllids, the proventricle region has a significant role during stolonization and reproduction processes in Typosyllis antoni. When the proventricle region is absent, anterior and posterior regeneration are considerably deviated from the general patterns. However, proventricle ultrastructure does not show any glandular component, thereby questioning a direct involvement of this organ itself in the control of reproduction and regeneration. Our findings offer a comprehensive starting point for further studies of regeneration and reproductive control in syllids as well as annelids in general
Cellular proliferation dynamics during regeneration in Syllis malaquini (Syllidae, Annelida)
BACKGROUND: In syllids (Annelida, Syllidae), the regenerative blastema was subject of many studies in the mid and late XX(th) century. This work on syllid regeneration showed that the blastema is developed by a process of dedifferentiation of cells near the wound, followed by their proliferation and redifferentiation (cells differentiate to the original cell type) or, in some specific cases, transdifferentiation (cells differentiate to a cell type different from the original). Up to date, participation of stem cells or pre-existing proliferative cells in the blastema development has never been observed in syllids. This study provides the first comprehensive description of Syllis malaquini’s regenerative capacity, including data on the cellular proliferation dynamics by using an EdU/BrdU labelling approach, in order to trace proliferative cells (S-phase cells) present before and after operation. RESULTS: Syllis malaquini can restore the anterior and posterior body from different cutting levels under experimental conditions, even from midbody fragments. Our results on cellular proliferation showed that S-phase cells present in the body before bisection do not significantly contribute to blastema development. However, in some specimens cut at the level of the proventricle, cells in S-phase located in the digestive tube before bisection participated in regeneration. Also, our results showed that nucleus shape allows to distinguish different types of blastemal cells as forming specific tissues. Additionally, simultaneous and sequential addition of segments seem to occur in anterior regeneration, while only sequential addition was observed in posterior regeneration. Remarkably, in contrast with previous studies in syllids, sexual reproduction was not induced during anterior regeneration of amputees lacking the proventricle, a foregut organ widely known to be involved in the stolonization control. CONCLUSIONS: Our findings led us to consider that although dedifferentiation and redifferentiation might be more common, proliferative cells present before injury can be involved in regenerative processes in syllids, at least in some cases. Also, we provide data for comparative studies on resegmentation as a process that differs between anterior and posterior regeneration; and on the controversial role of the proventricle in the reproduction of different syllid lineages. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12983-021-00396-y
The making of a branching annelid: an analysis of complete mitochondrial genome and ribosomal data of Ramisyllis multicaudata
Ramisyllis multicaudata is a member of Syllidae (Annelida, Errantia, Phyllodocida) with a remarkable branching body plan. Using a next-generation sequencing approach, the complete mitochondrial
genomes of R. multicaudata and Trypanobia sp. are sequenced and analysed, representing the first ones from Syllidae. The gene order in these two syllids does not follow the order proposed as the putative ground pattern in Errantia. The phylogenetic relationships of R. multicaudata are discerned using a phylogenetic approach with the nuclear 18S and the mitochondrial 16S and cox1 genes. Ramisyllis multicaudata is the sister group of a clade containing Trypanobia species. Both genera, Ramisyllis and Trypanobia, together with Parahaplosyllis, Trypanosyllis, Eurysyllis, and Xenosyllis are located in a long branched clade. The long branches are explained by an accelerated mutational rate in the 18S rRNA gene. Using a phylogenetic backbone, we propose a scenario in which the
postembryonic addition of segments that occurs in most syllids, their huge diversity of reproductive modes, and their ability to regenerate lost parts, in combination, have provided an evolutionary basis to develop a new branching body pattern as realised in Ramisyllis
Utilization of lactose and presence of the phospho-β-galactosidase (lacG) gene in Lactococcus garvieae isolates from different sources
This study evaluates the utilization of lactose (Lac) and the presence of the phospho-β-galactosidase (lacG) gene as markers for distinguishing between fish (Lac-/lacG-) and dairy isolates (Lac+/lacG+) of Lactococcus garvieae, using a panel of L. garvieae isolates from different sources. None of the fish isolates produced acid from lactose (Lac-), however Lac-/lacG- isolates were observed in pigs, cows, birds and humans. Most of the dairy isolates (77.8%) were Lac+/lacG+, but some dairy isolates did not produce acid from this sugar. Data in the present study show that the ability to metabolize lactose and the presence of the lacG gene are heterogeneously scattered among L. garvieae isolates of different sources. Therefore, the use of these criteria as markers to differentiate between L. garvieae isolates of dairy and fish origin should be considered with caution. [Int Microbiol 2010; 13(4):189-193
El uso de las piedras de corte en los monumentos y en la construcción: 1. Areniscas y calizas
Se describen diversas variedades de areniscas y calizas no pulimentadas empleadas habitualmente en la construcción, indicando en que terrenos aparecen y como se deteriora
Utilization of lactose and presence of the phospho-β-galactosidase (lacG) gene in Lactococcus garvieae isolates from different sources
This study evaluates the utilization of lactose (Lac) and the presence of the phospho-β-galactosidase (lacG) gene as markers for distinguishing between fish (Lac-/lacG-) and dairy isolates (Lac+/lacG+) of Lactococcus garvieae, using a panel of L. garvieae isolates from different sources. None of the fish isolates produced acid from lactose (Lac-), however Lac-/lacG- isolates were observed in pigs, cows, birds and humans. Most of the dairy isolates (77.8%) were Lac+/lacG+, but some dairy isolates did not produce acid from this sugar. Data in the present study show that the ability to metabolize lactose and the presence of the lacG gene are heterogeneously scattered among L. garvieae isolates of different sources. Therefore, the use of these criteria as markers to differentiate between L. garvieae isolates of dairy and fish origin should be considered with caution
La academia, la historia de las mujeres y las historiadoras
Entenem que els estudis de gènere tenen com a objectiu crear i desenvolupar un coneixement científic on siguin presents les dones amb una nova metodologia que contempli les relacions entre homes i dones. Però aquest coneixement no deu romandre estanc en els “tallers” que conformen els congressos de caràcter nacional o internacional que s'organitzen periòdicament, ni tampoc en les ponents convidades als mateixos. Invitació convertida en una mena de diàleg de “dones que parlen per a les dones sobre altres dones” i, en el pitjor dels casos, en un soliloqui inútil i estèril. La complaença de veure com figuren els temes de gènere en els programes dels congressos i com són desenvolupats per aquelles col·legues (sempre dones) que millor els dominen, per la seva especialització i dedicació durant anys, pot disfressar la realitat i oferir-nos en la seva lloc un "mirall d'igualtat" fabricat per la forma subtil en què es manifesta de vegades el patriarcat i la relacions entre homes i dones.We understand that gender studies aim to create and develop scientific knowledge where women are present with a new methodology that contemplates the relationships between men and women. But this knowledge should not remain stagnant in the "workshops" that make up the national or international congresses that are periodically organized, nor in the speakers invited to them. Invitation turned into a kind of dialogue of "women who speak for women about other women" and, in the worst case, into a useless and sterile soliloquy. The satisfaction of seeing how gender issues appear in the conference programs and how they are developed by those colleagues (always women) who best master them, due to their specialization and dedication over the years, can disguise reality and offer us in its instead a “mirage of equality” fabricated by the subtle way in which patriarchy and relations between men and women are sometimes manifested.Entendemos que los estudios de género tienen como objetivo crear y desarrollar un conocimiento científico donde estén presentes las mujeres con una nueva metodología que contemple las relaciones entre hombres y mujeres. Pero este conocimiento no debe de permanecer estanco en los “talleres” que conforman los congresos de carácter nacional o internacional que se organizan periódicamente, ni tampoco en las ponentes invitadas a los mismos. Invitación convertida en una suerte de diálogo de “mujeres que hablan para las mujeres sobre otras mujeres” y, en el peor de los casos, en un soliloquio inútil y estéril. La complacencia de ver cómo figuran los temas de género en los programas de los congresos y cómo son desarrollados por aquellas colegas (siempre mujeres) que mejor los dominan, por su especialización y dedicación durante años, puede disfrazar la realidad y ofrecernos en su lugar un “espejismo de igualdad” fabricado por la forma sutil en la que se manifiesta a veces el patriarcado y la relaciones entre hombres y mujeres
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From Epidemic Meningitis Vaccines for Africa to the Meningitis Vaccine Project
Background. Polysaccharide vaccines had been used to control African meningitis epidemics for >30 years but with little or modest success, largely because of logistical problems in the implementation of reactive vaccination campaigns that are begun after epidemics are under way. After the major group A meningococcal meningitis epidemics in 1996–1997 (250 000 cases and 25 000 deaths), African ministers of health declared the prevention of meningitis a high priority and asked the World Health Organization (WHO) for help in developing better immunization strategies to eliminate meningitis epidemics in Africa. Methods. WHO accepted the challenge and created a project called Epidemic Meningitis Vaccines for Africa (EVA) that served as an organizational framework for external consultants, PATH, the US Centers for Disease Control and Prevention (CDC), and the Bill & Melinda Gates Foundation (BMGF). Consultations were initiated with major vaccine manufacturers. EVA commissioned a costing study/business plan for the development of new group A or A/C conjugate vaccines and explored the feasibility of developing these products as a public–private partnership. Representatives from African countries were consulted. They confirmed that the development of conjugate vaccines was a priority and provided information on preferred product characteristics. In parallel, a strategy for successful introduction was also anticipated and discussed. Results. The expert consultations recommended that a group A meningococcal conjugate vaccine be developed and introduced into the African meningitis belt. The results of the costing study indicated that the “cost of goods” to develop a group A – containing conjugate vaccine in the United States would be in the range of US1.35 per dose, depending on composition (A vs A/C), number of doses/vials, and presentation. Following an invitation from BMGF, a proposal was submitted in the spring of 2001. Conclusions. In June 2001, BMGF awarded a grant of US$70 million to create the Meningitis Vaccine Project (MVP) as a partnership between PATH and WHO, with the specific goal of developing an affordable MenA conjugate vaccine to eliminate MenA meningitis epidemics in Africa. EVA is an example of the use of WHO as an important convening instrument to facilitate new approaches to address major public health problems
Indicators of Good Practices of Service-Learning University
The proliferation of innovative experiences in university education has been confirmed in different forums, as well as the evidence of their impact in research. However, the available tools are limited when trying to address the quality assessment of University Service-Learning (USL) projects. We present a tool for the evaluation of your SL projects. The goal of the Matrix is to specify the essential and secondary indicators needed to develop good practices in USL: IM_USL.
A protocol is established to carry out its assessment. Dimensions and phases indicators of a project are specied, as well as the agents or people involved in it. This tool tries to guide the development of USL projects and to specify different points to improve. The application of the IM_USL will allow you to explore, exhaustively, each of the dimensions and indicators that make up a USL project, regarding both the AGENTS involved and the PHASES that make up a programme. In order to gather information on the reality of the projects, the phases and agents involved in a USL project will be reviewed in particular, determining the level of achievement of the indicators that compose it and of the dimensions that specify the particularities of each indicator. Finally, a series of questions are proposed to guide the process of analysis and reflection on the quality of the evaluated project. As a result, we will be able to obtain an X-ray of the quality of the project and the possible aspects for improvement.Funding: Spanish Ministry of Science and Innovation.
Grant: I+D 2019. REFERENCIA DEL PROYECTO/AEI/10.13039/50110001103
Multidisciplinary exercises: coordination practices and applications from fundamental to applied subjects in agriculture engineering
This activity is carried out in the framework of an innovation project, whose main objective is to coordinate mathematical, physical and engineering contents for a transversal educational path focused on mechatronics, automated control and information and communication technologies. In such sense one important task in this project is the elaboration of practices and joint applications which will be proposed to the students in successive matters upon different points of view: “Common Practices”. Through this activity students will be guided to establish relationships between their scientific basic training and their technological formation. The students will work on the same example during different academic years and semesters using common materials and working spaces. The whole experience will be displayed in Moodle, a virtual learning environment. A preliminary proposal of “Common practice” is presented in this paper as one example: “Design and Analysis of Suspensions Systems for Stabilizing the Roll of Spray Booms”. In this example students of different academic levels are asked to solve the complexity of the problem along different subjects: Field measurements (analysis of variability on chemical applications using a spray boom) will be realized in the Agriculture Machinery topic - equivalent to 4.5 ECTS -. Analytical models for the analysis of different suspension systems in the Mechanics and Mechanisms topic -4.5 ECTS -. In Agriculture Applied Electronics – 2.5 ECTS – sensors and actuators will be studied to design controllers. Control strategies for damping the resonance frequency of the suspension will be studied in Process Simulation and Optimization – 3.5 ECTS –. And, finally, the design and development of a vehicle with a spray bar and the corresponding suspension systems will be done in the Robotics topic – 7 ECTS –
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