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Keywords = comb jelly

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12 pages, 2550 KiB  
Article
Feeding Habits of the Invasive Ctenophore Mnemiopsis leidyi in the Gulf of Trieste (Adriatic Sea)
by Borut Mavrič, Danijel Ivajnšič, Davor Lučić, Alenka Malej and Lovrenc Lipej
Water 2025, 17(4), 470; https://doi.org/10.3390/w17040470 - 7 Feb 2025
Viewed by 1264
Abstract
The diet of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste was examined during its peak occurrence in the summer and early-autumn months (July to October) from 2017 to 2019, through the analysis of stomach contents. Altogether 506 specimens were individually [...] Read more.
The diet of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste was examined during its peak occurrence in the summer and early-autumn months (July to October) from 2017 to 2019, through the analysis of stomach contents. Altogether 506 specimens were individually caught for the analysis. A total of 3215 prey items were isolated and identified. Copepods emerged as the primary prey (relative abundance 66.7%), followed by cladocerans (7.7%), and bivalve larvae (6%). Notably, specimens of M. leidyi constituted a significant portion of the diet (5.4.%), providing further evidence of cannibalism within this species. Copepods were also the most commonly occurring prey items in the diet of M. leidyi. Most of them were represented by calanoid and cyclopoid nauplii (48.2%), followed by a harpacticoid M. norvegica (28.3%), and calanoids (26.8%). Other frequently occurring taxa were bivalve larvae (19.3%), M. leidyi (18.7%), and cladoceran Penilia avirostris (16.1%). The rate of cannibalism peaked in July, coinciding with a period of limited food availability. Additionally, the study revealed that fish eggs and larvae were infrequently found in the stomachs of M. leidyi. However, the presence of massive aggregations of M. leidyi may impact microzooplankton populations in late summer or autumn, potentially leading to competition with small pelagic fish. Full article
(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)
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12 pages, 2396 KiB  
Article
Effects of Sucrose Feeding on the Quality of Royal Jelly Produced by Honeybee Apis mellifera L.
by Ying Wang, Lanting Ma, Hongfang Wang, Zhenguo Liu, Xuepeng Chi and Baohua Xu
Insects 2023, 14(9), 742; https://doi.org/10.3390/insects14090742 - 4 Sep 2023
Cited by 8 | Viewed by 2869
Abstract
Royal jelly (RJ) is a highly nutritious secretion of the honeybees’ hypopharyngeal glands (HPGs). During RJ production, colonies are occasionally subjected to manual interventions, such as sucrose feeding for energy supplementation. This study aimed to assess the impact of sucrose feeding on the [...] Read more.
Royal jelly (RJ) is a highly nutritious secretion of the honeybees’ hypopharyngeal glands (HPGs). During RJ production, colonies are occasionally subjected to manual interventions, such as sucrose feeding for energy supplementation. This study aimed to assess the impact of sucrose feeding on the composition of RJ. The results indicated that RJ obtained from sucrose-fed colonies exhibited significantly higher levels of fructose, alanine, glycine, tyrosine, valine, and isoleucine compared to the honey-fed group. However, no significant differences were observed in terms of moisture content, crude protein, 10-HDA, glucose, sucrose, minerals, or other amino acids within the RJ samples. Moreover, sucrose feeding did not have a significant effect on midgut sucrase activity, HPGs development, or the expression levels of MRJP1 and MRJP3 in nurse bees. Unsealed stored food samples from sucrose-fed bee colonies demonstrated significantly higher sucrose levels compared to sealed combs and natural honey. Additionally, natural honey exhibited higher moisture and Ca levels, as well as lower levels of Zn and Cu, in comparison to honey collected from bee colonies fed sucrose solutions. Based on these findings, we conclude that sucrose feeding has only a minor impact on the major components of RJ. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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17 pages, 3566 KiB  
Article
Antimicrobial Peptides Originating from Expression Libraries of Aurelia aurita and Mnemiopsis leidyi Prevent Biofilm Formation of Opportunistic Pathogens
by Lisa Ladewig, Leon Gloy, Daniela Langfeldt, Nicole Pinnow, Nancy Weiland-Bräuer and Ruth A. Schmitz
Microorganisms 2023, 11(9), 2184; https://doi.org/10.3390/microorganisms11092184 - 29 Aug 2023
Cited by 4 | Viewed by 1904
Abstract
The demand for novel antimicrobial compounds is rapidly growing due to the rising appearance of antibiotic resistance in bacteria; accordingly, alternative approaches are urgently needed. Antimicrobial peptides (AMPs) are promising, since they are a naturally occurring part of the innate immune system and [...] Read more.
The demand for novel antimicrobial compounds is rapidly growing due to the rising appearance of antibiotic resistance in bacteria; accordingly, alternative approaches are urgently needed. Antimicrobial peptides (AMPs) are promising, since they are a naturally occurring part of the innate immune system and display remarkable broad-spectrum activity and high selectivity against various microbes. Marine invertebrates are a primary resource of natural AMPs. Consequently, cDNA expression (EST) libraries from the Cnidarian moon jellyfish Aurelia aurita and the Ctenophore comb jelly Mnemiopsis leidyi were constructed in Escherichia coli. Cell-free size-fractionated cell extracts (<3 kDa) of the two libraries (each with 29,952 clones) were consecutively screened for peptides preventing the biofilm formation of opportunistic pathogens using the crystal violet assay. The 3 kDa fraction of ten individual clones demonstrated promising biofilm-preventing activities against Klebsiella oxytoca and Staphylococcus epidermidis. Sequencing the respective activity-conferring inserts allowed for the identification of small ORFs encoding peptides (10–22 aa), which were subsequently chemically synthesized to validate their inhibitory potential. Although the peptides are likely artificial products from a random translation of EST inserts, the biofilm-preventing effects against K. oxytoca, Pseudomonas aeruginosa, S. epidermidis, and S. aureus were verified for five synthetic peptides in a concentration-dependent manner, with peptide BiP_Aa_5 showing the strongest effects. The impact of BiP_Aa_2, BiP_Aa_5, and BiP_Aa_6 on the dynamic biofilm formation of K. oxytoca was further validated in microfluidic flow cells, demonstrating a significant reduction in biofilm thickness and volume by BiP_Aa_2 and BiP_Aa_5. Overall, the structural characteristics of the marine invertebrate-derived AMPs, their physicochemical properties, and their promising antibiofilm effects highlight them as attractive candidates for discovering new antimicrobials. Full article
(This article belongs to the Special Issue Feature Papers in Microbial Biofilms)
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22 pages, 4371 KiB  
Article
Honey Bee Exposure to the Fungicide Propiconazole in Lowbush Blueberry Fields
by Francis Andrew Drummond
Agronomy 2022, 12(12), 3081; https://doi.org/10.3390/agronomy12123081 - 5 Dec 2022
Cited by 8 | Viewed by 3455
Abstract
The fungicide propiconazole is a commonly used fungicide in small fruit and tree fruit production in the U.S.A. In Maine wild blueberry production, it is used almost exclusively for mummy berry disease control. The goal of this study is to assess the risk [...] Read more.
The fungicide propiconazole is a commonly used fungicide in small fruit and tree fruit production in the U.S.A. In Maine wild blueberry production, it is used almost exclusively for mummy berry disease control. The goal of this study is to assess the risk of exposure to honey bee colonies deployed in wild blueberry fields for pollination. The study was conducted over a six-year period (2009–2014) in both the field and laboratory. Field surveys (2009–2011) measured the residues on blueberry flowers in 41 commercial fields across the blueberry growing region. A two-year study (2010–2011) determined the decay rate of propiconazole in blueberry fields after application. A laboratory study determined the contact LD50 of propiconazole to honey bee workers (2013). A field exposure/effect study was conducted over three years (2011–2013). In this study, 8–18 previously unexposed colonies were randomly assigned to one of two treatments, (1) isolated fields that were treated prior to bloom with the fungicide, propiconazole, but no other pesticides, or (2) isolated fields that were not treated with propiconazole or any other pesticides. The measures taken to evaluate effects of exposure monitored each year were (1) estimation of the exposure to colonies, measured as residues on flowers, workers, and in pollen brought back to hives; (2) colony population size (workers and brood); (3) queen status and presence; (4) queen oviposition rate; (5) supersedure rate; (6) egg hatch success; (7) mortality of developing larvae and pupae; (8) royal jelly deposition in wax comb cells; (9) worker longevity; (10) foraging activity; (11) treated bloom repellency to foragers; (12) colony overwintering success; (13) worker hypopharyngeal gland acini size; and (14) pathogen and parasite incidence and intensity. The results of these experiments and surveys showed that the propiconazole contact LD50 was 24,747 ppb. Residues of propiconazole were found to be commonly abundant on flowers in treated commercial fields after application with a mean concentration of 2083.8 ± 851.3 (se). The decay of propiconazole to non-detectable levels took about 40 days after application. The three-year hive deployment study showed that residues in treated fields were detected on flowers, pollen, and worker bees, demonstrating that exposure to this fungicide occurs even though it is applied before bloom. Also in the hive deployment study, evidence of reduced colony populations, increased supersedure, decreased queen oviposition rate, increased pathogen or parasite incidence and intensity, and increased overwintering colony loss due to propiconazole exposure was not found. However, propiconazole exposed colonies exhibited reduced worker longevity (17.3%), hypertrophy of 5 d old nurse bee hypopharyngeal acini (8.3%), and a 3.5 h repellency of foragers to treated bloom. Full article
(This article belongs to the Special Issue Ecological Research on Crop Pollinators)
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15 pages, 2815 KiB  
Review
Whole-Body Regeneration in the Lobate Ctenophore Mnemiopsis leidyi
by Allison Edgar, Dorothy G. Mitchell and Mark Q. Martindale
Genes 2021, 12(6), 867; https://doi.org/10.3390/genes12060867 - 5 Jun 2021
Cited by 19 | Viewed by 10677
Abstract
Ctenophores (a.k.a. comb jellies) are one of the earliest branching extant metazoan phyla. Adult regenerative ability varies greatly within the group, with platyctenes undergoing both sexual and asexual reproduction by fission while others in the genus Beroe having completely lost the ability to [...] Read more.
Ctenophores (a.k.a. comb jellies) are one of the earliest branching extant metazoan phyla. Adult regenerative ability varies greatly within the group, with platyctenes undergoing both sexual and asexual reproduction by fission while others in the genus Beroe having completely lost the ability to replace missing body parts. We focus on the unique regenerative aspects of the lobate ctenophore, Mnemiopsis leidyi, which has become a popular model for its rapid wound healing and tissue replacement, optical clarity, and sequenced genome. M. leidyi’s highly mosaic, stereotyped development has been leveraged to reveal the polar coordinate system that directs whole-body regeneration as well as lineage restriction of replacement cells in various regenerating organs. Several cell signaling pathways known to function in regeneration in other animals are absent from the ctenophore’s genome. Further research will either reveal ancient principles of the regenerative process common to all animals or reveal novel solutions to the stability of cell fates and whole-body regeneration. Full article
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22 pages, 5312 KiB  
Review
Diversity and Physiological Tolerance of Native and Invasive Jellyfish/Ctenophores along the Extreme Salinity Gradient of the Baltic Sea
by Cornelia Jaspers, Nicholas Bezio and Hans-Harald Hinrichsen
Diversity 2021, 13(2), 57; https://doi.org/10.3390/d13020057 - 2 Feb 2021
Cited by 17 | Viewed by 8759
Abstract
Global change has led to manifold changes of marine ecosystems and biodiversity world-wide. While it has been shown that certain jellyfish and comb jelly species have increased regionally, it remains to be investigated if this is a general trend or localized phenomenon. Especially [...] Read more.
Global change has led to manifold changes of marine ecosystems and biodiversity world-wide. While it has been shown that certain jellyfish and comb jelly species have increased regionally, it remains to be investigated if this is a general trend or localized phenomenon. Especially for the economically important Baltic Sea, which is characterized by an extreme physical environmental gradient, this question has not been addressed to date. Here we present a detailed account of the gelatinous macro-zooplankton community including their physiological tolerance towards abiotic conditions and resulting distribution ranges in the Baltic. We show that the arrival and establishment of non-indigenous species has led to a rising importance of jellyfish and comb jellies in the Baltic. This accounts for the comb jelly Mnemiopsis leidyi, which was first observed in Northern Europe in 2005, as well as for the hydromedusae Blackfordia virginica, first sighted in 2014. Both species have been shown to attain high population densities with pronounced grazing impact in other invasive regions. Given the current and anticipated changes of the physical environment of the Baltic Sea, especially ongoing warming, amplification of their impact can be expected. Full article
(This article belongs to the Special Issue Patterns and Ecology of Jellyfish in Marine Environment)
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