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Neurobiology of Disease May 2024CLN8 is an endoplasmic reticulum cargo receptor and a regulator of lysosome biogenesis whose loss of function leads to neuronal ceroid lipofuscinosis. CLN8 has been...
CLN8 is an endoplasmic reticulum cargo receptor and a regulator of lysosome biogenesis whose loss of function leads to neuronal ceroid lipofuscinosis. CLN8 has been linked to autophagy and lipid metabolism, but much remains to be learned, and there are no therapies acting on the molecular signatures in this disorder. The present study aims to characterize the molecular pathways involved in CLN8 disease and, by pinpointing altered ones, to identify potential therapies. To bridge the gap between cell and mammalian models, we generated a new zebrafish model of CLN8 deficiency, which recapitulates the pathological features of the disease. We observed, for the first time, that CLN8 dysfunction impairs autophagy. Using autophagy modulators, we showed that trehalose and SG2 are able to attenuate the pathological phenotype in mutant larvae, confirming autophagy impairment as a secondary event in disease progression. Overall, our successful modeling of CLN8 defects in zebrafish highlights this novel in vivo model's strong potential as an instrument for exploring the role of CLN8 dysfunction in cellular pathways, with a view to identifying small molecules to treat this rare disease.
PubMed: 38763444
DOI: 10.1016/j.nbd.2024.106536 -
Environment International May 2024Liquid crystal monomers (LCMs) are the raw material for liquid crystal displays, and their use is steadily increasing in electronic products. Recently, LCMs have been...
Liquid crystal monomers (LCMs) are the raw material for liquid crystal displays, and their use is steadily increasing in electronic products. Recently, LCMs have been reported to be novel endocrine disrupting chemicals, however, the mechanisms underlying their potential for thyroid hormone disruption and visual toxicity are not well understood. In this study, six widely used fluorinated LCMs (FLCMs) were selected to determine putative mechanisms underlying FLCM-induced toxicity to the zebrafish thyroid and visual systems. Exposure to FLCMs caused damage to retinal structures and reduced cell density of ganglion cell layer, inner nuclear layer, and photoreceptor layer approximately 12.6-46.1%. Exposure to FLCMs also disrupted thyroid hormone levels and perturbed the hypothalamic-pituitary-thyroid axis by affecting key enzymes and protein in zebrafish larvae. A thyroid hormone-dependent GH3 cell viability assay supported the hypothesis that FLCMs act as thyroid hormone disrupting chemicals. It was also determined that FLCMs containing aliphatic ring structures may have a higher potential for T3 antagonism compared to FLCMs without an aliphatic ring. Molecular docking in silico suggested that FLCMs may affect biological functions of thyroxine binding globulin, membrane receptor integrin, and thyroid receptor beta. Lastly, the visual motor response of zebrafish in red- and green-light was significantly inhibited following exposure to FLCMs. Taken together, we demonstrate that FLCMs can act as thyroid hormone disruptors to induce visual dysfunction in zebrafish via several molecular mechanisms.
PubMed: 38761427
DOI: 10.1016/j.envint.2024.108747 -
Ecotoxicology and Environmental Safety May 2024Over the past few years, there has been growing interest in the ability of insect larvae to convert various organic side-streams containing mycotoxins into insect...
Over the past few years, there has been growing interest in the ability of insect larvae to convert various organic side-streams containing mycotoxins into insect biomass that can be used as animal feed. Various studies have examined the effects of exposure to aflatoxin B (AFB) on a variety of insect species, including the larvae of the black soldier fly (BSFL; Hermetia illucens L.; Diptera: Stratiomyidae) and the housefly (HFL; Musca domestica L.; Diptera: Muscidae). Most of these studies demonstrated that AFB degradation takes place, either enzymatic and/or non-enzymatic. The possible role of feed substrate microorganisms (MOs) in this process has thus far not been investigated. The main objective of this study was therefore to investigate whether biotransformation of AFB occurred and whether it is caused by insect-enzymes and/or by microbial enzymes of MOs in the feed substrate. In order to investigate this, sterile and non-sterile feed substrates were spiked with AFB and incubated either with or without insect larvae (BSFL or HFL). The AFB concentration was determined via LC-MS/MS analyses and recorded over time. Approximately 50% of the initially present AFB was recovered in the treatment involving BSFL, which was comparable to the treatment without BSFL (60%). Similar patterns were observed for HFL. The molar mass balance of AFB for the sterile feed substrates with BSFL and HFL was 73% and 78%, respectively. We could not establish whether non-enzymatic degradation of AFB in the feed substrates occurred. The results showed that both BSFL and substrate-specific MOs play a role in the biotransformation of AFB as well as in conversion of AFB into aflatoxin P and aflatoxicol, respectively. In contrast, HFL did not seem to contribute to AFB degradation. The obtained results contribute to our understanding of aflatoxin metabolism by different insect species. This information is crucial for assessing the safety of feeding fly larvae with feed substrates contaminated with AFB with the purpose of subsequent use as animal feed.
PubMed: 38759532
DOI: 10.1016/j.ecoenv.2024.116449 -
Journal of Chromatography. B,... May 2024Depending on the respective research question, LC-MS/MS based bottom-up proteomics poses challenges from the initial biological sample all the way to data evaluation....
Depending on the respective research question, LC-MS/MS based bottom-up proteomics poses challenges from the initial biological sample all the way to data evaluation. The focus of this study was to investigate the influence of sample preparation techniques and data analysis parameters on protein identification in Tribolium castaneum by applying free software proteomics platform Max Quant. Multidimensional protein extraction strategies in combination with electrophoretic or chromatographic off-line protein pre-fractionation were applied to enhance the spectrum of isolated proteins from T. castaneum and reduce the effect of co-elution and ion suppression effects during nano-LC-MS/MS measurements of peptides. For comprehensive data analysis, MaxQuant was used for protein identification and R for data evaluation. A wide range of parameters were evaluated to gain reproducible, reliable, and significant protein identifications. A simple phosphate buffer, pH 8, containing protease and phosphatase inhibitor cocktail and application of gentle extraction conditions were used as a first extraction step for T.castaneum proteins. Furthermore, a two-dimensional extraction procedure in combination with electrophoretic pre-fractionation of extracted proteins and subsequent in-gel digest resulted in almost 100% increase of identified proteins when compared to chromatographic fractionation as well as one-pot-analysis. The additionally identified proteins could be assigned to new molecular functions or cell compartments, emphasizing the positive effect of extended sample preparation in bottom-up proteomics. Besides the number of peptides during post-processing, MaxQuant's Match between Runs exhibited a crucial effect on the number of identified proteins. A maximum relative standard deviation of 2% must be considered for the data analysis. Our work with Tribolium castaneum larvae demonstrates that sometimes - depending on matrix and research question - more complex and time-consuming sample preparation can be advantageous for isolation and identification of additional proteins in bottom-up proteomics.
PubMed: 38759531
DOI: 10.1016/j.jchromb.2024.124128 -
Bird Conservation International 2024The endemic Little Vermilion Flycatcher (LVF), , has suffered a drastic decline on Santa Cruz Island, where it was common 30 years ago. Currently, less than 40...
The endemic Little Vermilion Flycatcher (LVF), , has suffered a drastic decline on Santa Cruz Island, where it was common 30 years ago. Currently, less than 40 individuals remain in the last remnants of natural humid forest in the Galapagos National Park on this island. This small population has low reproductive success, which is contributing to its decline in Santa Cruz. Previous studies have identified Avian Vampire Fly, , parasitism, changes in food sources, and habitat alteration as threats to this species. In Santa Cruz, invasive plants may strongly affect the reproductive success of the LVF because they limit accessibility to prey near the ground, the preferred foraging niche of these birds. Since 2019, we restored the vegetation in seven plots of one hectare each by removing invasive blackberry plants and other introduced plant species. In all nests that reached late incubation, we also reduced the number of Avian Vampire Fly larvae. In this study, we compared foraging and perch height, pair formation, incubation time and reproductive success between managed and unmanaged areas. As predicted, we found significantly lower foraging height and perch height in 2021 in managed areas compared to unmanaged areas. In 2020, daily failure rate (DFR) of nests in the egg stage did not differ between management types; however, in 2021, DFR in the egg stage was significantly lower in managed areas than in unmanaged areas. The DFR during the nestling stage was similar between managed and unmanaged areas in 2020, but in 2021, only nests in managed areas reached the nestling stage. Females brooded significantly more during the incubation phase in managed areas. Additionally, we found significantly higher reproductive success in managed areas compared to unmanaged areas in 2021, but not in 2020. Habitat restoration is a long-term process and these findings suggest that habitat management positively affects this small population in the long term.
PubMed: 38756994
DOI: 10.1017/S0959270924000091 -
Frontiers in Microbiology 2024Yeast is one of the important symbiotic flora in the insect gut. However, little is known about the gut yeast in (Lepidoptera: Noctuidae) under various dietary...
Yeast is one of the important symbiotic flora in the insect gut. However, little is known about the gut yeast in (Lepidoptera: Noctuidae) under various dietary conditions. The composition and function of the intestinal yeast community also remain unclear. In this research, we explored the composition of yeast microorganisms in larvae under different feeding environments, including apple, pear, tomato, artificial diet (laboratory feeding), , , and (wild environment) using high-throughput sequencing. Results showed that a total of 43 yeast OTU readings were obtained, comprising 33 yeast genera and 42 yeast species. The yeast genera with a total content of more than 5% were (36.27%), (21.47%), (16.20%), (12.96%) and (6.38%). was predominant when fed indoors with fruits, whereas was only detected in the wild group (, , ) and the artificial diet group. After transferring the larvae from artificial diet to apple, pear and tomato, the composition of intestinal yeast community changed, mainly reflected in the increased relative abundance of and the decreased abundance of . Simultaneously, the results of α diversity index indicated that the intestinal yeast microbial diversity of fed on wild plants was higher than that of indoor artificial feeding. PCoA and PERMANOVA analysis concluded that there were significant differences in the gut yeast composition of larvae on different diets. Our results confirmed that gut yeast communities of can be influenced by host diets and may play an important role in host adaptation.
PubMed: 38756734
DOI: 10.3389/fmicb.2024.1287083 -
Frontiers in Microbiology 2024Entomopathogenic fungi (EPF) are economical and environmentally friendly, forming an essential part of integrated pest management strategies. We screened six strains of...
Entomopathogenic fungi (EPF) are economical and environmentally friendly, forming an essential part of integrated pest management strategies. We screened six strains of (B1-B6) (Hypocreales: Cordycipitaceae), of which B4 was the most virulent to (Hendel) (Diptera: Tephritidae). We further assessed the biological characteristics of strain B4 and the environmental factors influencing its ability to infect . We also evaluated the effects of B4 on two of the natural predators of . We found that strain B4 was the most virulent to 3rd instar larvae, pupae, and adult , causing mortality rates of 52.67, 61.33, and 90.67%, respectively. B4 was not toxic to eggs. The optimum B4 effects on were achieved at a relative humidity of 91-100% and a temperature of 25°C. Among the six insecticides commonly used for control, 1.8% abamectin emulsifiable concentrate had the strongest inhibitory effect on B4 strain germination. B4 spraying affected both natural enemies ( and ), reducing the number of and killing adults. We found a valuable strain of EPF (B4) that is virulent against many life stages of and has great potential for the biological control of . We also provide an important theoretical and practical base for developing a potential fungicide to control .
PubMed: 38756732
DOI: 10.3389/fmicb.2024.1362089 -
BMC Microbiology May 2024The world faces a major infectious disease challenge. Interest in the discovery, design, or development of antimicrobial peptides (AMPs) as an alternative approach for...
BACKGROUND
The world faces a major infectious disease challenge. Interest in the discovery, design, or development of antimicrobial peptides (AMPs) as an alternative approach for the treatment of bacterial infections has increased. Insects are a good source of AMPs which are the main effector molecules of their innate immune system. Black Soldier Fly Larvae (BSFL) are being developed for large-scale rearing for food sustainability, waste reduction and as sustainable animal and fish feed. Bioinformatic studies have suggested that BSFL have the largest number of AMPs identified in insects. However, most AMPs identified in BSF have not yet undergone antimicrobial evaluation but are promising leads to treat critical infections.
RESULTS
Jg7197.t1, Jg7902.t1 and Jg7904.t1 were expressed into the haemolymph of larvae following infection with Salmonella enterica serovar Typhimurium and were predicted to be AMPs using the computational tool ampir. The genes encoding these proteins were within 2 distinct clusters in chromosome 1 of the BSF genome. Following removal of signal peptides, predicted structures of the mature proteins were superimposed, highlighting a high degree of structural conservation. The 3 AMPs share primary sequences with proteins that contain a Kunitz-binding domain; characterised for inhibitory action against proteases, and antimicrobial activities. An in vitro antimicrobial screen indicated that heterologously expressed SUMO-Jg7197.t1 and SUMO-Jg7902.t1 did not show activity against 12 bacterial strains. While recombinant SUMO-Jg7904.t1 had antimicrobial activity against a range of Gram-negative and Gram-positive bacteria, including the serious pathogen Pseudomonas aeruginosa.
CONCLUSIONS
We have cloned and purified putative AMPs from BSFL and performed initial in vitro experiments to evaluate their antimicrobial activity. In doing so, we have identified a putative novel defensin-like AMP, Jg7904.t1, encoded in a paralogous gene cluster, with antimicrobial activity against P. aeruginosa.
Topics: Animals; Defensins; Anti-Bacterial Agents; Diptera; Larva; Microbial Sensitivity Tests; Amino Acid Sequence; Insect Proteins; Antimicrobial Peptides; Salmonella typhimurium; Gram-Negative Bacteria
PubMed: 38755524
DOI: 10.1186/s12866-024-03325-1 -
Parasitology Research May 2024The metastrongyloid nematode Angiostrongylus cantonensis causes eosinophilic meningitis in a variety of homeothermic hosts including humans. Third-stage infectious...
The metastrongyloid nematode Angiostrongylus cantonensis causes eosinophilic meningitis in a variety of homeothermic hosts including humans. Third-stage infectious larvae develop in gastropods as intermediate hosts. Humans are usually infected by intentional or incidental ingestion of an infected mollusk or paratenic host (poikilothermic vertebrates and invertebrates). The infection may also hypothetically occur through ingestion of food or water contaminated by third-stage larvae spontaneously released from gastropods. Larvae are thought to be released in greater numbers from the intermediate host exposed to stress. This study aimed to compare larval release from stressed with unstressed gastropods. Experimentally infected Limax maximus and Lissachatina fulica were exposed to a stress stimulus (shaking on an orbital shaker). The mucus was collected before and after the stress and examined microscopically and by qPCR for the presence of A. cantonensis larvae and their DNA. In the case of L. maximus, no larvae were detected microscopically in the mucus, but qPCR analysis confirmed the presence of A. cantonensis DNA in all experimental replicates, without clear differences between stressed and non-stressed individuals. In contrast, individual larvae of A. cantonensis were found in mucus from Li. fulica after stress exposure, which also reflects an increased number of DNA-positive mucus samples after stress. Stress stimuli of intensity similar to the transport or handling of mollusks can stimulate the release of larvae from highly infected intermediate hosts. However, these larvae are released in small numbers. The exact number of larvae required to trigger neuroangiostrongyliasis is unknown. Therefore, caution is essential when interacting with potential intermediate hosts in regions where A. cantonensis is endemic.
Topics: Animals; Angiostrongylus cantonensis; Larva; Stress, Physiological; Gastropoda; Strongylida Infections; Mucus; Real-Time Polymerase Chain Reaction
PubMed: 38755287
DOI: 10.1007/s00436-024-08232-y -
Scientific Reports May 2024Seagrass habitats play a major role in fisheries productivity through nursery functions and feeding grounds for diverse fish species. However, little is known about the...
Seagrass habitats play a major role in fisheries productivity through nursery functions and feeding grounds for diverse fish species. However, little is known about the seasonal distribution of fish larvae at large spatial scales in coastal East Africa. We investigated drivers of the seasonal fish larvae abundance and composition in seagrass habitats in Kenya and Tanzania. We found a high diversity of fish larvae (54 families) inhabiting seagrass habitats that differed between sites and seasons. Fish larvae abundance were highest in Kenya, particularly during the northeast monsoon season. Overall, total larval abundances per site were low, reaching less than 190 individuals/100 m in Kenya and less than 40 individuals/100 m in Tanzania, likely related to the low productivity and strong hydrodynamic processes in this region. Our data suggests that most of the fish spawn year-round in these tropical waters as we did not find strong seasonal patterns. All sites had a high relative abundance of larvae from demersal spawning fishes, indicating that many fish species move to coastal sites for spawning. Primary productivity and dissolved oxygen, driven by hydrodynamics conditions are positively related to fish larvae productivity both in Kenya and Tanzania. These findings indicate that the occurrence of both resident and transient fish larvae in seagrass meadows is driven by strong hydrodynamic and tidal processes that transport fish larvae across adjacent habitats.
Topics: Animals; Seasons; Fishes; Larva; Ecosystem; Kenya; Tanzania; Africa, Eastern; Biodiversity
PubMed: 38755235
DOI: 10.1038/s41598-024-62012-3