Search

Mountain ranges are known for their particular level of biodiversity typically including a striking amount of endemism. This has been comparatively well studied for certain mountain ranges worldwide such as the Alps in Europe, the Himalayas in Asia, the Rocky Mountains in North America and the Andes in South America. Apparently, this is not the case for the mountains on the African continent and especially their freshwater fauna. One of Africa's largest high-elevated regions is the Ethiopian Highlands. The study of freshwater molluscs might potentially allow to provide valuable insights into the interplay of environmental variation and evolutionary change. Here, we present the first genetically based study of Afromontane sphaeriid bivalves in a worldwide phylogenetic framework which allowed us to assess and describe the recent diversity and endemism as well as the fauna's biogeographic background. Additionally, a new Ethiopian species of Sphaeriidae, Pisidium boessnecki Albrecht & Clewing sp. nov., could be discovered and is formally described here. Our study revealed a total of six sphaeriid species for the restricted study region in the Ethiopian Highlands of which the first two are most likely endemic: Pisidium boessnecki sp. nov., P. ethiopicum, P. cf. kenianum, P. cf. pirothi, P. cf. viridarium, and Pisidium sp. V. Based on the multigene phylogeny generated, we conclude that the observed diversity might have been caused by multiple independent colonization events from Africa. The zoogeographic affinities of all Ethiopian sphaeriids are related to the Afrotropics. The importance of these findings is discussed. [ABSTRACT FROM AUTHOR]

Galba humilis (Say, 1822) is a freshwater mollusc belonging to the family Lymnaeidae, and it is distributed in North America. The present article documented the first record of this mollusc in Japan, which is outside the indigenous distribution range of the species. The species was identified using molecular phylogenetics. This is the first report of G. humilis introduction in the world, including Japan. [ABSTRACT FROM AUTHOR]

Pomacea sp. is a freshwater gastropod that is capable of withstanding oxidative stress during extreme environmental changes. The snail enzymatic oxidative responses have already been elucidated through biochemical, transcriptomics, and proteomics analysis. However, their non-enzymatic oxidative responses have yet to be elucidated. Therefore, this study aims to characterize the antioxidant activity and identify the non-enzymatic antioxidant compounds from Pomacea maculata. To address the aims, a polar and non-polar extraction of snail-whole body extract was conducted using methanol and chloroform, respectively. The antioxidant activity of both extracts was elucidated by Folin Ciocalteau (FC), DPPH, and reducing power assay. LCMS/MS was then used to profile both extracts. The results demonstrated that the crude methanol extract (CME) contains a higher antioxidant capacity (FC=43.22 ± 3.02 mg GAE/g extract, DPPH IC50=0.073 mg/mL, and reducing the power of methanol and chloroform extract are 0.361 ± 0.07 and 0.051 ± 0.003 respectively). Profiling of the snail metabolites by LCMS/MS from both extracts resulted in the identification of uric acid and phenolic compounds. The former was detected at the highest intensity in CME followed by crude chloroform extract (CCE). The phenolic compounds, however, were hypothetically identified as plant metabolites. Therefore, the study suggested that antioxidant activity exhibited by P. maculata extracts were due to non-enzymatic compounds such as uric acid and phenolic compounds originated from the animal's metabolic activity and plants, respectively. [ABSTRACT FROM AUTHOR]

Cage fish farming is an important economic activity in Brazil where tilapia (Oreochromis niloticus) is the main cultivated species. To investigate the cage fish farm as a vector for golden mussel invasion, we hypothesised that: (1) Limnoperna fortunei, a freshwater bivalve mollusc, finds greater food availability in the cage fish farm; (2) the cage fish farm favours mollusc colonisation and its nutritional status; and (3) its performance in the reservoir would vary over the year.We obtained data from limnological variables as well as the number of larvae and adult individuals, to evaluate condition index (CI) monthly from February 2015 to January of 2016. We established sampling stations at three points with fish farming and three points without fish farming (controls) in the Canoas II Reservoir, Paranapanema River, Brazil. We used principal component analysis (PCA) to identify spatial and temporal distribution of samples according to limnological variables. We performed a linear mixed model analysis to test the hypothesis of no difference between areas (fish farm and control) and time (months) for larval density and CI of L. fortunei.The first PCA axis (28.48% of variance) revealed a temporal gradient, showing the separation between cold and hot months. The second PCA axis (19.61% of variance) separated the samples of control and fish farms; fish farms displayed higher concentrations of total phosphorus, nitrite, and chlorophyll a. Larval densities of L. fortunei were higher in fish cage areas with time being responsible for 35% of this variation. Mussel CI was also higher in fish farms and time was responsible for 36% of the variation.We conclude that fish production in cages contributes to the establishment of golden mussels in the reservoir. Our results serve as a warning that other molluscs or invasive species may be favoured by aquaculture activities in aquatic environments. The colonisation of the mussel in the reservoir varies during the year in response to seasonality. [ABSTRACT FROM AUTHOR]

Abstract: The macromolecules contributed by the freshwater gastropod Biomphalaria glabrata, intermediate host of Schistosoma mansoni, to developing offspring inside egg masses are poorly known. SDS-PAGE fractionated egg mass fluids (EMF) of M line and BB02 B. glabrata were analyzed by MALDI-TOF (MS and tandem MS). A MASCOT database was assembled with EST data from B. glabrata and other molluscs to aid in sequence characterization. Of approximately 20 major EMF polypeptides, 16 were identified as defense-related, including protease inhibitors, a hemocyanin-like factor and tyrosinase (each with possible phenoloxidase activity), extracellular Cu–Zn SOD, two categories of C-type lectins, Gram-negative bacteria-binding protein (GNBP), aplysianin/achacin-like protein, as well as versions of lipopolysaccharide binding protein/bacterial permeability-increasing proteins (LBP/BPI) that differed from those previously described from hemocytes. Along with two sequences that were encoded by “unknown” ESTs, EMF also yielded a compound containing a vWF domain that is likely involved in defense and a polypeptide with homology to the Aplysia pheromone temptin. Further study of B. glabrata pheromones is warranted as these could be useful in efforts to control these schistosome-transmitting snails. Several of the EMF polypeptides were contained in the albumen gland, the organ that produces most EMF. Thus, parental investment of B. glabrata in immunoprotection of its offspring is indicated to be considerable. [Copyright &y& Elsevier]

A survey of freshwater molluscs was conducted in southern Manitoba in 1998 and was compared with a similar survey from 1975-1978. Sites were classified according to main type of human impact: crops, livestock, logging, recreation, mining, hydro and minimal impact. All development categories increased at the expense of minimal impact sites. Frequencies of freshwater mussels and most gastropods declined, and some species recorded in the earlier survey were not found in 1998. Meanspecies richness of gastropod communities decreased at all site categories. The lowest richness was consistently observed at sites affected by mining and intensive livestock production. Small gastropod species appeared to show the most precipitous declines. [ABSTRACT FROM AUTHOR]

Two bivalve species (Anodonta sp. and Unio pictorum) and two gastropod species (Radix ovata and Viviparus sp.) were tested as bioindicators in moderately metal-polluted Danube River habitats of Vienna. Molluscs, two sediment fractions and water samples were collected betweenApril 1993 and May 1994 at six sampling sites located at five watersin Vienna. The unionid clams were dissected into viscera, gill, mantle, adductor muscle and shell, gastropods into soft body and shell. Analyses of Cd, Pb, Cu and Zn were carried out with atomic absorption spectrophotometry. Bioaccumulation of metals varied strongly according to sampling site, metal and mollusc species. Cd, Cu and Zn loads ofthe molluscs exceeded environmental concentrations, but not so for the apparently less bioavailable Pb. Sampling site had a significant influence on metal bioconcentrations, e.g. the Neue Donau sampling sites, where traffic emissions probably caused increased metal contents.High environmental metal concentrations in Danube harbours were poorly reflected by the bioindicator species. The gastropods showed about20-fold higher concentrations than the bivalves. This may indicate ahigher Cu regulation capacity of bivalves. The suitability of the investigated mollusc species as bioindicators depends on their specificrelationship to the environmental compartment. Anodonta sp. and R. ovata concentrations were more likely related to the contents of the fine sediment fraction, which may be explained by their close association to the sediments. The metal concentrations of the deposit- and filter-feeder Viviparus sp. correlated more closely with suspended matter and filtrate contents. [ABSTRACT FROM AUTHOR]