Effect of starvation and subsequent feeding on glycogen concentration, behavior and mortality in the golden mussel Limnoperna Fortunei (Dunker, 1857) (Bivalvia: Mytilidae)

The success of Limnoperna fortunei as an invasive species is related to its physiological plasticity that allows them to endure adverse environmental conditions. Starvation tolerance is considered to be an important trait associated with bivalve invasiveness. In natural ecosystems, food resources can vary during the year, exposing mussels to variable periods of starvation or limited food availability. Thus, mussels have developed physiological strategies to tolerate fluctuations in food availability. Glycogen concentration has been used in different monitoring studies as an indicator of the nutritional condition of bivalves. The aim of this study was to investigate the physiological responses of L. fortunei based on the glycogen concentrations of specimens under four treatments, comprising differentcombinations of feeding and starvation, during 125 days. The experiment was carried out in two phases. In the phase I, mussels were divided in two treatments: starvation (S) and feeding (F). After 100 days, tissue samples were collected to quantify glycogen concentrations and, each phase I group was divided in two subgroups: starvation (S) and feeding (F), resulting in four treatments. In the phase II, that lasted 25 days, starvation specimens (S) from phase I were allowed to feed (starvation-feeding treatment, or S-F), or continued to undergo starvation (starvation-starvation treatment, or S-S) and the feeding specimens (F) continued feeding (feeding-feeding group, or F-F), or were subjected to starvation (feeding-starvation treatment, or F-S). Behavior (valve-closing) and mortality were recorded in 24 h intervals. After the 25 days (phase II) all specimens were killed, and thei r soft tissue was removed to quantify glycogen concentrations. The glycogen concentration of the S-F treatment was lower than that of the F-S treatment, which was initially allowed to feed (phase I) and then subjected to starvation (phase II). Stability in the glycogen concentrations was observed when the phase II feeding conditions were maintained during the experiments, as observed in the S-S (continued starvation) and F-F (continued feeding) treatments. Based on our glycogen concentrations results, the golden mussel shows a higher tolerance to starvation (125 days) than has previously been published, which suggests that its tolerance strongly influences its invasive behavior.Facultad de Ciencias Naturales y Muse

Effect of starvation and subsequent feeding on glycogen concentration, behavior and mortality in the golden mussel Limnoperna Fortunei (Dunker, 1857) (Bivalvia: Mytilidae)

The success of Limnoperna fortunei as an invasive species is related to its physiological plasticity that allows them to endure adverse environmental conditions. Starvation tolerance is considered to be an important trait associated with bivalve invasiveness. In natural ecosystems, food resources can vary during the year, exposing mussels to variable periods of starvation or limited food availability. Thus, mussels have developed physiological strategies to tolerate fluctuations in food availability. Glycogen concentration has been used in different monitoring studies as an indicator of the nutritional condition of bivalves. The aim of this study was to investigate the physiological responses of L. fortunei based on the glycogen concentrations of specimens under four treatments, comprising differentcombinations of feeding and starvation, during 125 days. The experiment was carried out in two phases. In the phase I, mussels were divided in two treatments: starvation (S) and feeding (F). After 100 days, tissue samples were collected to quantify glycogen concentrations and, each phase I group was divided in two subgroups: starvation (S) and feeding (F), resulting in four treatments. In the phase II, that lasted 25 days, starvation specimens (S) from phase I were allowed to feed (starvation-feeding treatment, or S-F), or continued to undergo starvation (starvation-starvation treatment, or S-S) and the feeding specimens (F) continued feeding (feeding-feeding group, or F-F), or were subjected to starvation (feeding-starvation treatment, or F-S). Behavior (valve-closing) and mortality were recorded in 24 h intervals. After the 25 days (phase II) all specimens were killed, and thei r soft tissue was removed to quantify glycogen concentrations. The glycogen concentration of the S-F treatment was lower than that of the F-S treatment, which was initially allowed to feed (phase I) and then subjected to starvation (phase II). Stability in the glycogen concentrations was observed when the phase II feeding conditions were maintained during the experiments, as observed in the S-S (continued starvation) and F-F (continued feeding) treatments. Based on our glycogen concentrations results, the golden mussel shows a higher tolerance to starvation (125 days) than has previously been published, which suggests that its tolerance strongly influences its invasive behavior.Facultad de Ciencias Naturales y Muse

Effect of starvation and subsequent feeding on glycogen concentration, behavior and mortality in the golden mussel Limnoperna Fortunei (Dunker, 1857) (Bivalvia: Mytilidae)

The success of Limnoperna fortunei as an invasive species is related to its physiological plasticity that allows them to endure adverse environmental conditions. Starvation tolerance is considered to be an important trait associated with bivalve invasiveness. In natural ecosystems, food resources can vary during the year, exposing mussels to variable periods of starvation or limited food availability. Thus, mussels have developed physiological strategies to tolerate fluctuations in food availability. Glycogen concentration has been used in different monitoring studies as an indicator of the nutritional condition of bivalves. The aim of this study was to investigate the physiological responses of L. fortunei based on the glycogen concentrations of specimens under four treatments, comprising differentcombinations of feeding and starvation, during 125 days. The experiment was carried out in two phases. In the phase I, mussels were divided in two treatments: starvation (S) and feeding (F). After 100 days, tissue samples were collected to quantify glycogen concentrations and, each phase I group was divided in two subgroups: starvation (S) and feeding (F), resulting in four treatments. In the phase II, that lasted 25 days, starvation specimens (S) from phase I were allowed to feed (starvation-feeding treatment, or S-F), or continued to undergo starvation (starvation-starvation treatment, or S-S) and the feeding specimens (F) continued feeding (feeding-feeding group, or F-F), or were subjected to starvation (feeding-starvation treatment, or F-S). Behavior (valve-closing) and mortality were recorded in 24 h intervals. After the 25 days (phase II) all specimens were killed, and thei r soft tissue was removed to quantify glycogen concentrations. The glycogen concentration of the S-F treatment was lower than that of the F-S treatment, which was initially allowed to feed (phase I) and then subjected to starvation (phase II). Stability in the glycogen concentrations was observed when the phase II feeding conditions were maintained during the experiments, as observed in the S-S (continued starvation) and F-F (continued feeding) treatments. Based on our glycogen concentrations results, the golden mussel shows a higher tolerance to starvation (125 days) than has previously been published, which suggests that its tolerance strongly influences its invasive behavior.Fil: Cordeiro, Nelmara I. S.. Universidade Federal de Minas Gerais; BrasilFil: Andrade, Jennifer T. M.. Universidade Federal de Minas Gerais; BrasilFil: Montresor, Lângia C.. Fundación Oswaldo Cruz; BrasilFil: Luz, Dalva M. R.. Universidade Federal de Minas Gerais; BrasilFil: Martinez, Carlos B.. Universidade Federal de Minas Gerais; BrasilFil: Darrigran, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; ArgentinaFil: Pinheiro, Jairo. Universidade Federal Rural Do Rio de Janeiro;Fil: Vidigal, Teofânia H. D. A.. Universidade Federal de Minas Gerais; Brasi

Effect of temperature on behavior, glycogen content, and mortality in Limnoperna fortunei (Dunker, 1857) (Bivalvia: Mytilidae)

Limnoperna fortunei (Dunker 1857) is a freshwater mussel with physiological tolerance to different environmental conditions, which may explain its success as an invasive species. The role of abiotic factors in its establishment, abundance and projections of risk of further spread into several areas has been studied. These mussels may respond to multiple environmental stressors, such as temperature, through physiological mechanisms, behavioral responses, mortality or some combination of these. The aim of this study was to investigate the behavioral responses (valve closing), glycogen concentrations and mortality of L. fortunei under four different temperatures (5°C, 10°C, 20°C and 30° C) during a chronic test (30 days). Two-way analysis of variance (ANOVA) was used to compare glycogen concentrations across days of the experiment and at the different temperatures. Differences in valve-closing behavior and mortality among temperatures were tested using repeated-measures ANOVA. We observed that most of the mussels maintained at 5°C closed their valves (74.7 ± 15.3%), indicating that they remain inactive at low temperatures. The glycogen levels significantly differed among the temperatures tested. These differences occurred mainly due to the high glycogen values observed in mussels exposed to 10°C. Stability in glycogen concentrations was observed within each particular temperature. The cumulative mortality was higher at extreme temperatures (5°C and 30°C). The ideal temperature for laboratory maintenance and tests is approximately 20°C. Our data also show that L. fortunei can survive and maintain their energy reserves (glycogen) for several days at 5°C, an important feature related to its invasion success

Molecular studies in Brazilian malacology: Tools, trends and perspectives

Made available in DSpace on 2015-10-02T12:45:05Z (GMT). No. of bitstreams: 2 license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) langia_montresor_etal_IOC_2013.pdf: 750672 bytes, checksum: d166a3d7603ea082e88cedc32dbbbed4 (MD5) Previous issue date: 2013Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Zoologia. Laboratório de Malacologia. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Zoologia. Laboratório de Malacologia. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Malacologia. Rio de Janeiro, RJ, Brasil.The use of molecular tools in Brazilian malacological studies was analyzed. We searched for these molecular tools by screening the annals of malacological events in Brazil and Latin America within the last 15 years. Information was obtained from a Brazilian curricula data bank (curriculum Lattes), which enabled the identification of the main national research groups, their main researchers and research focuses. An estimate of the scientific production on the basis of the analysis of these curricula is also provided. The main techniques and molecular markers employed were indicated. The data showed that these studies were concentrated in institutions in the South and Southeast regions and emphasized gastropods of medical importance. However, molecular studies that examined other gastropods, cephalopods and bivalves were also performed. No research study was found in the Central-West region of the country. The growth of this field of study in the country is expected, considering the molecular studies that have been performed and the great diversity of the molluscan fauna in Brazil. Future molecular studies on some taxa in the country, which have not yet been studied, should be contemplated. The increase in the use of sequencing techniques will help to bridge the gaps in our taxonomic and phylogenetic knowledge, contributing to the studies on biodiversity and conservation

Polymerase Chain Reaction and Restriction Fragment Length Polymorphism of Cytocrome Oxidase Subunit I Used for Differentiation of Brazilian Biomphalaria Species Intermediate Host of Schistosoma mansoni

The intermediate hosts of Schistosoma mansoni   , in Brazil, Biomphalaria glabrata   , B. tenagophila and B. straminea , were identified by restriction fragment length polymorphism analysis of the mitochondrial gene cytochrome oxidase I (COI). We performed digestions with two enzymes (AluI and RsaI), previously selected, based on sequences available in Genbank. The profiles obtained with RsaI showed to be the most informative once they were polymorphic patterns, corroborating with much morphological data. In addition, we performed COI digestion of B. straminea snails from Uruguay and Argentina

Compatibility Polymorphism Based on Long-Term Host-Parasite Relationships: Cross Talking Between Biomphalaria glabrata and the Trematode Schistosoma mansoni From Endemic Areas in Brazil

Sympatric snail populations have been kept in the laboratory since the isolation of the parasite from the field. To evaluate the influence of the intermediate host in the infectivity of S. mansoni, this allopatric strain was compared to two sympatric strains, from different geographical origins, and with different time of maintenance in the laboratory. Snail–trematode compatibility was accessed for a total of nine possible combinations (three snail populations, three schistosome strains), using different charges of parasite: 1, 5, 10, and 15 miracidia/snail. Each S. mansoni strain was characterized according to its infectivity phenotype that reflects the efficiency of their infection mechanism and all B. glabrata populations were characterized according to its (in)compatible phenotype that reflects the level of (un)susceptibility they display. For all host-parasite combinations tested the dose-response relation indicated a trend for an increase in the infectivity of S. mansoni when higher miracidial doses were used. SmRES-2 presented the highest overall infectivity rate, especially in the SmRES-2/BgRES interaction with 15 miracidia/snail. However, SmRES was more infective to BgBAR than SmRES-2, indicating that SmRES strain was more infective at the first contact with this new host than after 2 years of interaction (SmRES-2). BgBAR presented the highest susceptibility to infection. SmRES and SmRES-2 are the same parasite strains. It seems that during these 2 years of interaction, BgBAR acted like a filter and shifted the compatibility polymorphism of the strain SmRES. SmRES-2 became more infective to BgRES (sympatric) than to BgBAR (allopatric), and conversely, SmRES was more infective to BgBAR (allopatric) than to BgRES (sympatric). This interplay suggests that epigenetic mechanisms are prompting these changes. This study concerns with infection of B. glabrata snails from different Brazilian localities with S. mansoni in allopatric and sympatric associations that will partially help in understanding the natural epidemiology of schistosomiasis within natural snail populations in watercourses. This work demonstrates that there is a shift on the compatibility polymorphism profile resulting from sympatric and allopatric interactions of B. glabrata and S. mansoni that constantly change during the time of interaction

Predicting the distribution of Omalonyx (Mollusca: Pulmonata: Succineidae) species from literature review, museum databases and new sampling efforts in Brazil

<div><p>Abstract Accurate distributional information is crucial for studies on systematics, biodiversity and conservation. To improve the knowledge regarding the geographical distribution of Omalonyx in South America, we present updated information based on data from a literature review, institutional collections and malacological surveys. All this information composed the dataset used to predict species distribution employing the Maximum Entropy Algorithm (MaxEnt). The model was run using data on species distribution, altitude and bioclimatic variables (WorldClim database). The model had consistent performance, and areas presenting similar conditions to areas where the species were recorded were considered areas of occurrence. The predicted occurrence areas included those that were already surveyed and those that are considered potential occurrence areas. The results demonstrate that the genus has widespread distribution in the Neotropical region and occurs in the tropical, temperate and arid regions of South America and Lesser Antilles. Omalonyx spp. were recorded in all South American countries and hydrographic regions. However, in some countries, there were only isolated records (ex: Colombia and Ecuador). Here, we also present the first record of Omalonyx spp. in four Brazilian States (Acre, Rondônia, Piaui, and Amapá). The genus was found in all hydrographic regions within Brazil and among 27 federative unities; it was absent from only two unities (Roraima State and Distrito Federal). This work contributes to the knowledge on Omalonyx spp. distribution and provides an important basis for the work of ecologists and taxonomists.</p></div

High connectivity and migration potentiate the invasion of Limnoperna fortunei (Mollusca: Mytilidae) in South America

Even after almost 30 years of Limnoperna fortunei introduction into South America, it is still unclear how the source and propagules are connected. Here, we present genetic evidence of population connectivity and gene flow of L. fortunei propagules from Asia into South America, proposing the main invasion routes into South America. To achieve that we expanded the sampling effort to cover all occurrence points of L. fortunei in South America. We sequenced the mtDNA COI gene and genotyped eight microsatellite loci (ML), and we evaluated the genetic source of the recently introduced population in Sobradinho hydroelectric power plant reservoir in Northeast Brazil. Our results revealed that China is the main genetic source of propagules for the Sobradinho population. We also found COI haplotypes and ML genotypes unique to South American populations, demonstrating a bridgehead effect likely caused by local mutation, adaptation, and admixture patterns that are maintained by high levels of gene flow among them. However, two genetic barriers were also detected. We concluded that L. fortunei is a well-established invader and is still rapidly expanding in Brazil, and the Amazon hydrographic basin is under an alarming threat of invasion.Fil: Ludwig, Sandra. Universidade Federal de Minas Gerais; BrasilFil: Sari, Eloisa H. R.. Universidade Federal de Minas Gerais; BrasilFil: Paixão, Hugo. Universidade Federal de Minas Gerais; BrasilFil: Montresor, Lângia C.. René Rachou Institute; BrasilFil: Araújo, Juliano. Universidade Federal de Minas Gerais; BrasilFil: Brito, Cristiana F. A.. René Rachou Institute; BrasilFil: Darrigran, Gustavo Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Pepato, Almir R.. Universidade Federal de Minas Gerais; BrasilFil: Vidigal, Teofania Heloisa Dutra Amorim. Universidade Federal de Minas Gerais; BrasilFil: Martinez, Carlos B.. Universidade Federal de Minas Gerais; Brasi