Crustacean Species Research Articles

The efficacy of electrical stunning of New Zealand rock lobster (Jasus edwardsii) and freshwater crayfish (Paranephrops zealandicus) using the Crustastun™.

Large numbers of decapod crustacea are farmed and harvested globally for human consumption. Growing evidence for the capacity of these animals to feel pain, and therefore to suffer, has led to increased concern for their welfare, including at slaughter. In New Zealand, decapod crustacea are protected by animal welfare legislation. There is a requirement that all farmed or commercially caught animals of these species killed for commercial purposes are first rendered insensible. The aim of this study was to evaluate the efficacy of the Crustastun™, a commercially available bench-top electrical stunner, in two commercially important New Zealand crustacean species; the rock lobster (Jasus edwardsii) and kōura (freshwater crayfish [Paranephrops zealandicus]). Animals were anaesthetised via intramuscular injection of lidocaine and instrumented to record the electrical activity of the nervous system, prior to being stunned according to the manufacturer's instructions. Stunning efficacy was determined by analysing neural activity and observing behaviour post stunning. All ten P. zealandicus and three J. edwardsii appeared to be killed outright by the stun. Of the remaining J. edwardsii, six exhibited some degree of muscle tone and/or slow unco-ordinated movements of the limbs or mouthparts after stunning, although there was no recovery of spontaneous or evoked movements. One J. edwardsii was unable to be stunned successfully, likely due to its very large size (1.76kg). None of the successfully stunned animals showed any evidence of return of awareness in the five minutes following stunning. It was concluded that the Crustastun™ is an acceptable method for killing P. zealandicus and for stunning all but the largest J. edwardsii.

Changes in bacterioplankton and zooplankton communities in response to Covid-19 forced lockdown at dolphin surfacing sites in the River Ganga

Abstract The spread of Covid-19 has reduced human intervention in aquatic ecosystems, which has shown a discernible improvement in air and water quality. Ganges River, being a historical, economic and cultural icon of India providing multiple ecosystem services as industrial, provisioning, regulatory and cultural services, constitutes an important habitat for Gangetic Dolphin (Platanista gangetica). The surfacing of dolphins in Ganga river is patchy and unpredictable. The present study unravels 25 different chemical, microbiological, biological and meta-genomics of most abundant bacteria at dolphin surfacing sites in Ganges water during October 2017 February 2018 and January 2021 to elicit the impact of Covid-19 lock down at the Garhmukteshwar (28.7601°N, 78.1437°E) stretch in Hapur district of Uttar Pradesh, India. The most abundant bacteria at dolphin surfacing site was Bacillus subtilis in February 2018 which was replaced by Aeromonas sp. in January 2021. The zooplankton community was dominated by rotifers during pre-Covid period however the dominance pattern recorded a shift towards larger herbivorous crustacean species during Covid −19 lock down. Overall bacterial count decreased whereas Chl a level increased during the lock down. The total zooplankton abundance did not show a significant difference, but relative proportion of larger herbivorous crustacean zooplankton increased in January 2021 samples. The present results convincingly establish effects of shutdown on chemical, metagenomics and biological components of the riparian ecosystem and the information of micro to mesoplanktonic community may be useful for characterizing dolphin surfacing sites, enhancing existing water quality monitoring efforts and also for human epidemiological studies associated with recreational use of Ganga water.

The effect of diflubenzuron (Dimilin® 25 WP) on some non-target aquatic insect and crustacean species

The study is aimed at evaluating, under laboratory conditions, the side effects of a commercial formulation of diflubenzuron (Dimilin® 25 WP), which is an insecticide considered a chitin synthesis inhibitor, on some non-targeted aquatic species. The effect of two lethal doses of Dimilin LC10 (3.9 ng/L) and LC50 (16 ng/L) previously determined on fourth instar larvae of Culex pipiens L. 1758 were tested on some non-target aquatic species, abundant in the Lake of Birds (Northeast Algeria), a site classified under Ramsar Convention. The tested species belonged to two classes of invertebrates (Insects and Crustaceans). The insects included four species of Heteroptera: Corixa punctata Illiger, 1807, Notonecta glauca Latreille, 1802, Anisops sardea Latreille, 1802 and Plea minutissima Leach, 1817, and one species of Coleoptera Berosus signaticollis Charpentier,1825. For benthic crustaceans Daphnia magna Straus, 1820 (Cladocera) was retained. The results showed significant mortality recorded in C. punctata and medium mortality for B. signaticollis, A. sardea, N. glauca, P. minutissima and D. magna. Three-way ANOVA indicated highly significant effects of species, dose, and time. According to the sensitivity to Dimilin, the pairwise comparison of Tukey's test indicates that the most sensitive species was C. punctata followed by B. signaticollis and the least sensitive was N. glauca, followed by D. magna; then A. sardea and finally P. minutissima.

Crustaceans of the Northwest Pacific Ocean: Species richness and distribution patterns

Biodiversity patterns of marine crustaceans are still unknown in many locations or might have been overlooked due to our knowledge gaps, despite increasing sampling and data sharing efforts during the last decades. By analysing big data extracted from open portals such as Ocean Biodiversity Information System (OBIS) and Global Biodiversity Information System (GBIF), we aim to revisit the distribution and biodiversity patterns of the highly speciose and abundant Crustacea in the Northwest Pacific (NWP) from shallowest depths to the deep sea. This study focussed on selected benthic and pelagic crustacean (sub) classes and their species richness, sampling effort, and expected species richness (ES50) using equal/sized hexagonal cells, 5° latitudinal bands, 500 m depth intervals were analyzed. Crustacean species richness was highest in the tropical Philippines as well as around the Japanese islands. Pelagic crustacean species richness peaked at 30° latitude and declined beyond that. Benthic taxa; however, depicted high levels of species richness across most of the latitudinal gradient, reaching its highest point at 45° latitude. Due to the prevalence of certain crustacean orders in the deep sea, benthic species richness showed a distribution pattern with two distinct peaks across bathymetric gradients; with highest species richness recorded at shallow-water depths and also at abyssal depths. The most important environmental drivers of benthic and pelagic crustacean species richness were primary productivity (positive correlation) and salinity (negative correlation). Our study provides first insights into biodiversity patterns of the highly diverse Crustacea in the NWP and highlights strong differences between benthic and pelagic taxa. The results presented here could help us to better understand whether benthic or pelagic taxa might respond differently to climate changes in the NWP based on their distinct physiological and biological characteristics. This information is crucial in establishing species management strategies and ecosystem restorations in both shallow water and deep-sea environments.

Dietary selenium supplementation alleviates low salinity stress in the Pacific white shrimp Litopenaeus vannamei: growth, antioxidative capacity and hepatopancreas transcriptomic responses.

Se is an essential trace element associated with animal growth and antioxidant and metabolic processes. However, whether Se, especially organic Se with higher bioavailability, can alleviate the adverse effects of low salinity stress on marine economic crustacean species has not been investigated. Accordingly, juvenile Pacific white shrimp (Litopenaeus vannamei) were reared in two culture conditions (low and standard salinity) fed diets supplemented with increasing levels of l-selenomethionine (0·41, 0·84 and 1·14 mg/kg Se) for 56 d, resulting in four treatments: 0·41 mg/kg under standard seawater (salinity 31) and 0·41, 0·84 and 1·14 mg/kg Se under low salinity (salinity 3). The diet containing 0·84 mg/kg Se significantly improved the survival and weight gain of shrimp under low salinity stress and enhanced the antioxidant capacity of the hepatopancreas. The increased numbers of B and R cells may be a passive change in hepatopancreas histology in the 1·14 mg/kg Se group. Transcriptomic analysis found that l-selenomethionine was involved in the regulatory pathways of energy metabolism, retinol metabolism and steroid hormones. In conclusion, dietary supplementation with 0·84 mg/kg Se (twice the recommended level) effectively alleviated the effects of low salinity stress on L. vannamei by regulating antioxidant capacity, hormone regulation and energy metabolism.

Human Health Risk Assessment of Heavy Metal Concentration in Seafood Collected from Pattani Bay, Thailand.

A significant impact of marine pollution is the contamination of seafood which has raised concerns due to its potential human health risks. This current study investigated seasonal bioaccumulation of 9 heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in 14 commercially important seafood species, including 4 fish, 5 molluscs, and 5 crustacean species. Samples were collected from Pattani Bay, Pattani province, Thailand, during the dry (July 2020) and wet (February 2021) seasons. The edible samples were analyzed for heavy metal concentrations using a flame atomic absorption spectrophotometer. The bioaccumulation trend of heavy metals decreased in the sequence of molluscs > crustaceans > fish. The possible human health risks associated with heavy metal-contaminated seafood consumption were assessed. The parameters investigated for non-carcinogenic and carcinogenic were target hazard quotient (THQ), total hazard index (HI), and target cancer risk (TR). The average ranges of THQs (7.79 × 10-8-8.97 × 10-3), HIs (4.30 × 10-5-1.55 × 10-2), and TRs (2.70 × 10-9-1.34 × 10-5) were observed in the studied seafood species. The results revealed no non-carcinogenic and carcinogenic health risks from consuming these 14 kinds of seafood.

Impact of Titanium Dioxide-Graphene Oxide (TiO2-GO) Composite Nanoparticle on the Juveniles of the Giant River Prawn, Macrobrachium rosenbergii: Physio-Biochemistry and Transcriptional Response

Nanomaterials are used in many fields, resulting in inevitably releasing into the aquatic environment. The presence of nanomaterials, including TiO2-GO in the aquatic environment, can be toxic to aquatic organisms. However, few studies have focused on the effects of TiO2-GO composite nanoparticle on crustaceans. In the present study, the giant river prawn Macrobrachium rosenbergii juveniles were exposed to two concentrations of TiO2-GO composite nanoparticle (0.1 and 0.5mg/L). The effects of TiO2-GO composite exposure on activities of digestive and antioxidant-related enzymes and expressions of growth and immune-related genes at the transcriptome were studied. The results showed that the survival rate and growth performance were not negatively affected by TiO2-GO composite at the two exposure levels. Nevertheless, exposure to TiO2-GO composite causes an effect on the activities of digestive and antioxidant enzymes in the juvenile prawns. The enzyme activities of CAT, SOD, GSH-Px, AMS, TPS, and LPS in the 0.1mg/L TiO2-GO composite experimental group were markedly reduced than those in the control group. Additionally, the expression level of genes involved in growth and immunity was significantly affected by TiO2-GO composite. After exposure to the 0.1mg/L TiO2-GO composite, the mRNA expression level of MSTN was significantly increased, but the level of EcR, Raptor, and CaBP was significantly decreased. However, the mRNA levels of the CTL, TLR, JAK, and STAT were significantly increased after exposure to the 0.5mg/L concentration of TiO2-GO composite. Furthermore, to understand the molecular mechanism of M. rosenbergii under TiO2-GO composite exposure, RNA-Seq was employed to analyze the changes of the muscle and hepatopancreas transcriptome. Compared with the control group, we identified 5166 and 4784 differentially expressed genes (DEGs) in the muscle and hepatopancreas, respectively (p < 0.05). Based on gene ontology and KEGG analysis, significant differences were observed in the DEGs involved in activity and binding, metabolism, immune response, and environmental information processing. These results showed that exposure to TiO2-GO composite nanoparticle led to the changes of enzyme activity and gene expression, suggesting that TiO2-GO composite existing in aquatic environments would disrupt the physiology of M. rosenbergii. This study will serve as a foundation for subsequent research into the evaluation of nanomaterial toxicity on crustacean species.

MORPHOMETRIC AND MERISTIC STUDY OF MANTIS SHRIMP (Harpiosquilla raphidae) IN SEI BEROMBANG WATERS, LABUHANBATU REGENCY, NORTH SUMATERA

As basic information on identification process, the morphometric and meristic of mantis shrimp study can be used to initiate of mantis shrimp resource from Indonesia especially from North Sumatera. Mantis shrimp (Harpiosquilla raphidea) have big chance as one of the potential crustacean species as the source nutrition of future but not used optimally. This research was used the quantitative method were determining the sampling point through the purposive random sampling method. This study was conducted from November 2021 to January 2022 in around of Sei Berombang coastal water. The H. raphidea samples was carried out at 3 observation sites using trawl nets. The morphometric result showed that H. raphidea body length size was found range from 8.45 to 30.32 cm. In the meristic analysis of mantis shrimp, there were 5-6 telson spines, 7-8 spines for dactylus, and 15-17 for propodus. These results were described that the body length size of mantis shrimp dominated by small size class. and with this part has confirmed that the mantis found in Berombang estuary waters is H. raphidea.

Microbial Interactions, Growth, and Health of Aquatic Species in Biofloc Systems

Biofloc technology involves the manipulation of the culture system’s carbon: nitrogen ratio to promote bacterial community growth to convert toxic nitrogenous wastes and organics into functional microbial protein; this protein can then be used as a food source and mediate water quality. Biofloc systems have several advantages, which include improved biosecurity, feed conversion, water use efficiency, and nutrient processing. Analyzing the nutritional value and the relationship between high production of aquacultural practices using biofloc is essential. Many studies have demonstrated that biofloc increases the growth of aquatic species by acting as a food source or providing bioactive compounds. Other than this, the beneficial micro-organisms in biofloc systems contain compounds such as organic acids that could resist the growth of pathogenic microbes. They will also serve as a natural probiotic and increase the immunity and survival of fish and shrimp. This technology could be useful for further integration within many aspects of aquaculture production when microbial interactions are considered. However, future studies must fully understand the principles and mechanisms behind the benefits of interactions between biofloc and cultured fish and crustacean species.

Identification of potential functions of polo-like kinase 1 in male reproductive development of the oriental river prawn (Macrobrachium nipponense) by RNA interference analysis.

Polo-like kinase 1 (Plk1) has multiple functions in the cell cycle, including in the maturation of centrosomes during the G2/M transition, the separation of centrosomes, and the activation of cyclin-dependent kinase 1 expression and spindle assembly. In this study, we investigated the potential regulatory roles of Plk1 in the reproductive development of the male oriental river prawn (Machrobrachium nipponense). The full cDNA sequence of Mn-Plk1 was 2360 base pairs long, with an open reading frame of 1836 base pairs encoding 611 amino acids. Protein sequence alignment identified a conserved serine/threonine kinase domain and two Polo-boxes. Phylogenetic tree analysis revealed that Mn-Plk1 had the closest evolutionary distance with Plk1s of freshwater prawns and then with those of crustacean species, whereas the evolutionary distance with mollusks was much more distant. Quantitative PCR analysis predicted that Mn-Plk1 plays essential roles in the regulation of gonad development. RNA interference analysis and histological observations showed that expression of insulin-like androgenic gland hormone decreased as the expression of Mn-Plk1 decreased, and fewer than 5% of cells were sperm cells at day 14 in the dsPlk1 injected prawns. This result indicated that Plk1 positively regulated testis development in M. nipponense by affecting the expression of this hormone. Our results highlight the functions of Plk1 in M. nipponense and provide valuable information that can be applied to establish artificial techniques to regulate testis development in this species.

Giáp xác ký sinh trên ghẹ chữ thập Charybdis feriata Linnaeus, 1758 khu vực vịnh Nha Trang

Charybdis feriata (Linnaeus, 1758) is wide distribution and high economic value species in many countries around the world. In Vietnam, Charybdis feriata is on the list of endangered species that need to be conserved. Parasites cause many effects on the growth and development of crabs, which may be one of the causes leading to the decline of host populations. This paper presents the species composition, parasitic sites and infection status of parasitic crustaceans on C. feriata in Nha Trang Bay. From 113 individuals of Charybdis feriata collected in June and July 2022, we have identified 6 species of parasitic crustaceans, of which 2 species have been recorded for the first time on this crab, including: Octolasmis neptuni, Semibalanus sp.. Each infested crab is infected with up to 5 species of parasites. Octolasmis angulata was the dominant species with the highest prevalence and median intensity of infection at 44.4% and 6.5 individuals/infected crabs, respectively. Comparison of infection status by sex and host size showed that Sacculina serenei infection rate was higher in female crabs than male crabs, while infection intensity in male crabs was higher than female crabs. The prevalence and intensity of infection with Octolasmis angulata species increased significantly with host size. There was no statistical difference between the different host groups of sex and size. The data on parasitic crustaceans on Charybdis feriata contribute to the basis for the recovery, sustainable development of this endangered species.

Automated tracking of aquatic crustaceans with potential application on the quantification of animals movement

Here, we present a set of algorithms using the Python programming language, that will allow using a routine for object detection and tracking in experimental videos. We developed a script, under the fundamentals of background subtraction and image thresholding (using the OpenCV package), that makes it possible to track a wide spectrum of animals under different conditions. We have validated this script through testing on semi-terrestrial and aquatic crustacean species and under different experimental scenarios (laboratory and field sampling and using video created under nocturnal and diurnal conditions). The open-source nature of the script allows for flexibility and scalability, so it can be easily customized and is thus transferable to other species/experiments in the context of behavioral ecology. The tracking script is easy customizable and free alternative to commercial video tracking systems and therefore, applicable to a wide variety of both educational and research programs.

Contamination from microplastics and other anthropogenic particles in the digestive tracts of the commercial species Engraulis encrasicolus and Sardina pilchardus

Fragments of microplastics (<5 mm) found in commercial species of fish, crustaceans, and bivalves, are an issue of global concern. The bioaccumulation of microplastics and other anthropogenic particles in different levels of the food web may provoke unwanted impacts on marine ecosystems and cause pernicious effects on human health. Here, we study the presence of anthropogenic particles and the fraction of microplastics in the target organs of two representative commercial fish species in Spain; the European anchovy (Engraulis encrasicolus) and the European pilchard (Sardina pilchardus). The individuals were sampled along the continental shelf of the Gulf of Cádiz, from the Bay of Cádiz to Cape Santa Maria. The isolation of the microplastics (MPs) was carried out with a complete alkaline-oxidant organic digestion (KOH-H2O2) of the digestive tract, including both the contents ingested and the muscle tissues. Anthropogenic particles were found in all individuals of both species with an average of 8.94 ± 5.11 items·ind−1. Fibres made up 93 % of the items while fragments and films were represented by the remaining 7 %. The average size of the anthropogenic particles was 0.89 ± 0.82 mm. In addition to the fragment and film particles identified as microplastics, 29 % of the fibres were estimated to be microplastics by Fourier-transform infrared spectroscopy (FTIR) analysis. The main polymer found in both species was nylon. No significant correlation was found between the abundance and size of anthropogenic particles ingested and individual size or other body variables. The analysis of similarities (ANOSIM) and the distanced-based multiple linear regression model showed a high homogeneity in anthropogenic particle contamination in both species throughout the study area along the continental shelf of the Gulf of Cádiz.

Ecological status of macrobenthic communities in the Saudi waters of the western Arabian Gulf

In view of the unique oceanographic conditions combined with human pressure, we assessed the ecological status of macrobenthos from the entire Saudi waters (including open waters and inner bays) of the Gulf in 2013. A total of 328 macrobenthic species (228 polychaete species, 47 crustacean species, 46 mollusc species, and seven species belonging to other taxa) was recorded from the study area. Species richness, species diversity, and density had an overall average ±SE of 34 ± 2.0, 4.02 ± 0.1 and 1,373 ± 160 ind. m−2, respectively. As per the results of AZTI’s Marine Biotic Index (AMBI), in open waters, 10% of stations belonged to undisturbed and the remaining 90% belonged to slightly disturbed categories, while in sheltered inner bays, 95% of the stations belonged to slightly disturbed and the remaining 5% belonged to moderately disturbed categories. According to Multivariate AMBI (M-AMBI), 4% of the stations showed high status, 74% good status, 23% moderate status and 1% poor status in open waters. In inner bays, 2% of the stations showed high status, 73% good status, 14% moderate status and 4% poor status. The open waters, where extensive industrial activities take place, are not under major stress, which might be due to the implementation of appropriate mitigation measures during the construction and operation of the offshore facilities and the natural dispersal of potential pollutants. The stressed conditions on benthos in inner bays might be due to coastal discharges besides extreme oceanographic conditions, including the poor water flushing rates, which increase the exposure to pollutants.

Small-scale population structuring results in differential susceptibility to pesticide exposure

Central European riverine networks are subject to widely varying local anthropogenic pressures, forcing species with limited dispersal abilities to adapt or become locally extinct. Previous catchment-wide studies have shown that some invertebrates tend to have pronounced population structuring throughout mountainous river networks, raising the question of whether this also translates into small-scale phenotypic differentiation and adaptation to local stressors. One such species is the headwater crustacean species Gammarus fossarum clade 11 (or lineage B), which we restudied in terms of population structure four years after first assessment. Our aim was not only to document the temporal stability/dynamics of the population structure, but we asked whether a small-scale genetic structuring also results in phenotypic differentiation and different susceptibility to a commonly applied pesticide. Therefore, we re-assessed population structure based on COI haplotypes and their frequencies, and quantified key parameters related to morphological and life-history differentiation. Furthermore, we examined the difference in sensitivity towards the pyrethroid insecticide deltamethrin. COI haplotype patterns were found to be stable over time and confirmed the small-scale population structuring within the catchment, with isolated headwater populations and connected downstream populations. While little life-history differentiation was observed, marked differences in susceptibility to the pyrethroid insecticide were found. Populations from pristine sites responded significantly more tolerant than populations from anthropogenically impacted sites—showing that prior exposure to a spectrum of stressors does not automatically increase tolerance to a specific stressor. Therefore, our study demonstrates that limited dispersal capacity is reflected not only in population structure, but also in small-scale variation in susceptibility to anthropogenic disturbance. The system thus provides a suitable experimental landscape to test the impact of further stressors (e.g., other novel entities, including pesticides with other modes of action) on locally isolated populations. Based on these findings, important recommendations for the protection of riverine species and their intraspecific genetic variation can be developed.

An improved duplex real-time PCR method for the systematic detection of commercially relevant crustaceans in food

Crustaceans are known food allergens that can cause severe reactions for allergic patients. Hitherto, methods to detect commercial relevant crustacean species often consist of many PCR systems. In this study, we developed a highly specific duplex PCR (polymerase chain reaction) method for the detection of most commercially relevant crustaceans in food. The nuclear 18S rRNA and the mitochondrial 16S rRNA genes were selected for the detection of the suborders Pleocyemata and Dendrobranchiata, respectively. Both suborders belong to the order Decapoda, which comprises about 96% of all crustaceans consumed as food. We cross-tested over 100 different plant and animal species, including 25 species of crustaceans and eight species of farmed insects. Eight different food products were tested, to ensure practical applicability. The limit of detection (LOD12) is 1 pg of crustacean DNA or 10 ppm (mg/kg) of crustacean sample in food matrix. Finally, a robustness test confirmed the practical use of the protocol.

A checklist of species of Podophryidae (Ciliophora: Suctoria) as Epibionts of Crustaceans

The epibiotic relationship between crustaceans and ciliates is frequent, for example, with species of suctorians. This work aims to present an updated list of species of the family Podophryidae worldwide distributed as epibionts of crustaceans and its geographic distribution. The available literature was checked, and all the species were verified. We found four species and four species indeterminata attached to 16 species of crustaceans. For the American continent, we obtained four species, and for Africa and Oceania, we did not find any species.

RNA interference analysis of potential functions of cyclin A in the reproductive development of male oriental river prawns (Macrobrachium nipponense).

Cyclin A (CycA) plays essential roles in regulating multiple steps of the cell cycle, and it affects gonad development in mammals and invertebrates. Previous RNA interference (RNAi) analysis revealed that knocking-down the expression of CycA in female oriental river prawns (Macrobrachium nipponense) inhibited ovarian development. CycA was also predicted to have regulatory roles in reproductive development of male M. nipponense based on significant changes of Mn-CycA expression after eyestalk ablation. The goal of this study was to investigate the potential functions of CycA in the reproductive development of male M. nipponense using RNAi and histological observations. Quantitative real-time PCR analysis revealed that both single-side and double-side eyestalk ablation stimulated the expressions of Mn-CycA, and the expression was higher in prawns with double-side eyestalk ablation (p < 0.05). Mn-CycA expression was significantly higher in the testis and androgenic gland during the reproductive season than during the non-reproductive season (p < 0.05). In the RNAi analysis, Mn-CycA expression significantly decreased after prawns were injected with dsCycA, and the expression of insulin-like androgenic gland hormone (Mn-IAG) also decreased as Mn-CycA expression decreased. This result indicated that CycA positively regulated the expression of IAG in M. nipponense. Histological observations revealed that the number of sperm decreased dramatically to <5% of the total cells in the testis of the dsCycA-treated group compared to that of control group on day 14, indicating that knockdown of Mn-CycA expression inhibited testis development by affecting the expression of Mn-IAG in M. nipponense. These results highlighted the functions of CycA in male reproductive development of M. nipponense, which can be applied to future studies of male reproduction in other crustacean species.

Detection of Fish Allergens in Foods Using an In-House Real-Time PCR Targeting the Ribosomal 18S rRNA Gene.

Fish is one of the major food allergens which, in sensitised individuals, can cause life-threatening allergic reactions, even when present in small amounts. To protect consumers' health, the correct labeling of foods is important. The objective of the present study was to validate an in-house real-time PCR method targeting the ribosomal 18S rRNA gene as universal DNA marker for the detection of fish in foods. The specificity of the primers was assessed on 20 fish species commonly marketed in the Mediterranean basin and other species of molluscs and crustaceans and foods of animal and plant origin. The absolute detection of the method was assessed using DNA extracted from a fish mixture and the SureFood® QUANTARD Allergen 40 reference material. The relative amount was assessed on a fish and béchamel sauce blend. Commercial food samples either labelled with or without fish in the ingredient list, were tested for the presence of fish DNA. The primer showed high specificity against the selected fish species. The limit of detection (LOD) and limit of quantification (LOQ) of the in-house method were 0.5 pg/µL and 5 pg/µL, respectively. The relative quantification in fish and béchamel blend samples detected a concentration as low as 0.000025%, corresponding to 0.25 mg/kg of fish, indicating the suitability of the method in a food matrix. The presence of fish DNA was always detected in commercial samples in which the presence of fish was listed in the ingredient list. The method was able to detect the presence of fish DNA also in samples in which the presence of fish was indicated as traces or was not declared on the label. The proposed method was demonstrated to be a reliable, specific, and sensitive method for the detection of fish allergens in foods. Therefore, the proposed real-time PCR method could be used as a useful instrument in the verification of compliance with allergen labelling regulations.

Impact of overgrazing and climate change on the lake ecosystem in arid region

Mongolia's geographical location, extreme climate, fragile ecosystems, agricultural dependence on climate requires adaptation to global climate change and smart usage of natural resources. The water level of most lakes in Mongolia had been steadily increasing from mid-1960s to 1995 and declining from 1996. The purpose of this study is to determine current condition by each ecosystem compartment in and around the Lake Duruutsagaan and to define cause of the lake shrinking and deterioration of ecosystem. The Lake Duruutsagaan ecosystem study was carried out in the following natural elements: climate, hydrology, hydrobiology, forest, soil, pasture, plant species composition, and animals. The lake surface area was slightly decreased by 24.21% from 10.02 km2 in 2003 to 7.59 km2 in 2017. The lake water is highly mineralized, probably due to increases of evaporation of water. Also elevated concentrations of some chemical elements are detected in the lake water, including Phosphorus (22.6 mg L-1) and Arsenic (198 mg L-1). The high concentration of these two elements shown different kind of pollution existed in the lake. Probably, arsenic content in lake water is related to the geological composition of surrounding area, but elevated concentration of P can be attributed to the nutrient pollution due to soil erosion in surrounding area of lake. Species diversity in this lake is limited and only a few species of crustaceans that can tolerate under high salinity and polluted condition are present. All of soil samples have a low content of clay particles (between 2.6-8.5%). According to the soil samples data, pasture land in study area is moderately 80.95%, strongly 7.04% deteriorated due to direct and indirect effects of overgrazing. Especially, natural regeneration is not observed in the forest area. According to the study results, current condition of Lake Duruutsagaan and its surrounding area is indicating the need for some protection and restoration management.