Insights from Melipona bicolor hybrid genome assembly: a stingless bee genome with chromosome-level scaffold
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SUBMITTER: Araujo N
PROVIDER: S-EPMC10863234 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:Stingless bee colonies typically consist of one single-mated mother queen and her worker offspring. The stingless bee Melipona bicolor (Hymenoptera: Apidae) shows facultative polygyny, which makes this species particularly suitable for testing theoretical expectations concerning social behavior. In this study, we investigated the social structure and genetic relatedness among workers from eight natural and six manipulated colonies of M. bicolor over a period of one year. The populations of M. bicolor contained monogynous and polygynous colonies. The estimated genetic relatedness among workers from monogynous and polygynous colonies was 0.75 ± 0.12 and 0.53 ± 0.16 (mean ± SEM), respectively. Although the parental genotypes had significant effects on genetic relatedness in monogynous and polygynous colonies, polygyny markedly decreased the relatedness among nestmate workers. Our findings also demonstrate that polygyny in M. bicolor may arise from the adoption of related or unrelated queens.
| S-EPMC3115332 | biostudies-literature
Project description:Olfactory learning and floral scents are co-adaptive traits in the plant-pollinator relationship. However, how scent relates to cognition and learning in the diverse group of Neotropical stingless bees is largely unknown. Here we evaluated the ability of Melipona eburnea to be conditioned to scent using the proboscis extension reflex (PER) protocol. Stingless bees did not show PER while harnessed but were able to be PER conditioned to scent when free-to-move in a mini-cage (fmPER). We evaluated the effect of: 1) unconditioned stimulus (US) reward, and 2) previous scent-reward associations on olfactory learning performance. When using unscented-US, PER-responses were low on day 1, but using scented-US reward the olfactory PER-response increased on day 1. On day 2 PER performance greatly increased in bees that previously had experienced the same odor and reward combination, while bees that experienced a different odor on day 2 showed poor olfactory learning. Bees showed higher olfactory PER conditioning to guava than to mango odor. The effect of the unconditioned stimulus reward was not a significant factor in the model on day 2. This indicates that olfactory learning performance can increase via either taste receptors or accumulated experience with the same odor. Our results have application in agriculture and pollination ecology.
| S-EPMC6920981 | biostudies-literature
Project description:BackgroundIn contrast to the essentially fully assembled genome sequences of the kinetoplastid pathogens Leishmania major and Trypanosoma brucei the assembly of the Trypanosoma cruzi genome has been hindered by its repetitive nature and the fact that the reference strain (CL Brener) is a hybrid of two distinct lineages. In this work, the majority of the contigs and scaffolds were assembled into pairs of homologous chromosomes based on predicted parental haplotype, inference from TriTryp synteny maps and the use of end sequences from T. cruzi BAC libraries.ResultsUltimately, 41 pairs of chromosomes were assembled using this approach, a number in agreement with the predicted number of T. cruzi chromosomes based upon pulse field gel analysis, with over 90% (21133 of 23216) of the genes annotated in the genome represented. The approach was substantiated through the use of Southern blot analysis to confirm the mapping of BAC clones using as probes the genes they are predicted to contain, and each chromosome construction was visually validated to ensure sufficient evidence was present to support the organization. While many members of large gene families are incorporated into the chromosome assemblies, the majority of genes excluded from the chromosomes belong to gene families, as these genes are frequently impossible to accurately position.ConclusionNow assembled, these chromosomes bring T. cruzi to the same level of organization as its kinetoplastid relatives and have been used as the basis for the T. cruzi genome in TriTrypDB, a trypanosome database of EuPathDB. In addition, they will provide the foundation for analyses such as reverse genetics, where the location of genes and their alleles and/or paralogues is necessary and comparative genome hybridization analyses (CGH), where a chromosome-level view of the genome is ideal.
| S-EPMC2698008 | biostudies-literature
Project description:There is growing evidence in the literature suggesting that caste differentiation in the stingless bee, Melipona scutellaris, and other bees in the genus Melipona, is triggered by environmental signals, particularly a primer pheromone. With the proper amount of food and a chemical stimulus, 25% of females emerge as queens, in agreement with a long-standing "two loci/two alleles model" proposed in the 1950s. We surmised that these larvae must be equipped with an olfactory system for reception of these chemical signals. Here we describe for the first time the diversity of antennal sensilla in adults and the morphology of larvae of M. scutellaris. Having found evidence for putative olfactory sensilla in larvae, we next asked whether olfactory proteins were expressed in larvae. Since the molecular basis of M. scutellaris is still unknown, we cloned olfactory genes encoding chemosensory proteins (CSP) and odorant-binding proteins (OBPs) using M. scutellaris cDNA template and primers designed on the basis CSPs and OBPs previously reported from the European honeybee, Apis mellifera. We cloned two CSP and two OBP genes and then attempted to express the proteins encoded by these genes. With a recombinant OBP, MscuOBP8, and a combinatorial single-chain variable fragment antibody library, we generated anti-MscuOBP8 monoclonal antibody. By immunohistochemistry we demonstrated that the anti-MscuOBP8 binds specifically to the MscuOBP8. Next, we found evidence that MscuOBP8 is expressed in M. scutellaris larvae and it is located in the mandibular region, thus further supporting the hypothesis of olfactory function in immature stages. Lastly, molecular modeling suggests that MscuOBP8 may function as a carrier of primer pheromones or other ligands.
| S-EPMC5396885 | biostudies-literature
Project description:The stingless bee, Melipona fasciculata Smith (Apidae, Meliponini), is a native species from Brazil. Their products have high biotechnological potential, however there are no studies about the biological activities of pollen collected by M. fasciculata. In this context, the present study investigated the chemical composition, anti-oxidant, anti-inflammatory, and analgesic activities of hydroethanolic pollen extracts collected by M. fasciculata in three cities in Maranhão State, Brazil. We verified the antioxidant activity of the extracts and inhibitory activity against the cyclooxygenase enzyme using in vitro assays and in allowed to select the extract with higher efficiency to be used on in vivo assays. In these trials, the selected extract showed high anti-inflammatory activity as well as nociceptive effects at central and peripheral level, suggesting that this extract acts on inhibition of histamine release and decreased synthesis of prostaglandins and the in-silico study suggested that polyphenols and acids fatty acids in the extract may be associated with these activities. The results of the present study report the high biological potential of pollen extract and we conclude that the pollen collected by M. fasciculata can be considered as the object of research for new pharmacological alternatives.
| S-EPMC6770349 | biostudies-literature
Project description:Brazil has the highest biodiversity of native stingless bees in the world. However, Brazilian regulations are based on protocols standardized by the Organization for Economic Cooperation and Development (OECD), which uses Apis mellifera as a model organism. The safety of the use of an exotic species as a substitute for a native species is a problem that concerns members of the academy and the government agencies responsible for studies of this nature in the neotropical regions where there are occurrences of stingless bee species. Regarding the exposure of larvae to pesticides, several indicators suggest that the same rearing method for A. mellifera cannot be applied to stingless bees, mainly because of their different feeding systems. Thus, it is necessary to establish an in vitro rearing method for native social bees. We developed a larval rearing method for the stingless bee species Melipona scutellaris and evaluated parameters such as the defecation rate, pupation, emergence, mortality and morphometry of the newly emerged workers. The control was represented by the morphometry of individuals that emerged from natural combs (in vivo). In addition, we determined the average lethal concentration (LC50) of the insecticide dimethoate, the standard active ingredient used for the validation of toxicity tests. Procedures conducted prior to the in vitro bioassays allowed us to obtain the actual dimensions of the rearing cells for making acrylic plates for use in establishing how much each larva consumes during its development, that is, determining how much larval food should be placed in every artificial cell. Tests performed with M. scutellaris indicated an average of 80.2% emergence of individuals relative to the larvae, 92.61% relative to the pupae and a mean of 7.42% larval mortality. The mean of the intertegular distance, head width and wing asymmetry parameters were not significantly different between individuals from the in vitro and in vivo rearing methods. The LC50 value determined was 27.48 ng dimethoate / μL diet. The method described for M. scutellaris showed development rates above OECD standards, which requires at least 75% emergence, and produced newly emerged workers with similar dimensions to those produced under natural conditions; thus these results enable their use as a rearing protocol for this species (or genus) and, consequently, their use in toxicity tests. The results produced with M. scutellaris are the first steps for a proposed toxicity test protocol for stingless bee larvae that can be standardized and included as a protocol in the OECD.
| S-EPMC6426188 | biostudies-literature
Project description:Stingless bees, important pollinating insects in the tropics, produce honey whose unique quality features differentiate their origin. The feasibility of multivariate data analysis for quality discrimination of stingless bee honey from different genera (Melipona bicolor, quadrifasciata, marginata and Scaptotrigona bipunctata) by mineral content, physicochemical and microbiological properties were investigated. The principal component analysis explained 72.12% of the total variance of the data, and the separation into two main groups in a scatter plot was observed. Group 2 was formed by Scaptotrigona genus, that showed the highest values of pH, ash, and soluble solids. Potassium was the most abundant mineral followed by calcium and sodium for both groups quantified by inductively coupled plasma optical emission spectrometry. This honey has higher acidity and moisture than Apis mellifera honey. Microbiological analyses showed that total aerobic mesophiles ranged between 2.00 and 4.77 log CFU/g. Salmonella spp. was not detected, while the mould and yeast content was above the maximum allowed under the Apis mellifera honey legislation. The evaluated honey samples presented the lactic acid bacteria, which are considered a benefit. The multivariate statistical analysis was efficient in discriminate stingless bee honey, contributing to approaches that can be used for standardization and regulation.
| S-EPMC6801274 | biostudies-literature
Project description:Melipona scutellaris is a Brazilian stingless bee that is important for pollinating wild flora and agriculture crops. Fungicides have been widely used in agriculture, and floral residues can affect forager bees. The goal of our study was to evaluate the effects of sublethal concentrations of pyraclostrobin on the midgut ultrastructure of M. scutellaris forager workers. The bees were collected from three non-parental colonies and kept under laboratory conditions. The bees were orally exposed continuously for five days to pyraclostrobin in syrup at concentrations of 0.125 ng a.i./µL (FG1) and 0.005 ng a.i./µL (FG2). The control bees (CTL) were fed a no-fungicide sucrose solution, and the acetone solvent control bees (CAC) received a sucrose solution containing acetone. At the end of the exposure, the midguts were sampled, fixed in Karnovsky solution, and routinely processed for transmission electron microscopy. Ultrastructural analysis demonstrated that both the fungicide concentrations altered the midgut, such as cytoplasmic vacuolization (more intense in FG1), the presence of an atypical nuclear morphology, and slightly dilated mitochondrial cristae in the bees from the FG1 and FG2 groups (both more intense in FG1). Additionally, there was an alteration in the ultrastructure of the spherocrystals (FG1), which could be the result of cellular metabolism impairment and the excretion of toxic metabolites in the digestive cells as a response to fungicide exposure. The results indicate that ingested pyraclostrobin induced cytotoxic effects in the midgut of native stingless bees. These cellular ultrastructural responses of the midgut are a prelude to a reduced survival rate, as observed in previous studies.
| S-EPMC10748086 | biostudies-literature
Project description:The species Melipona rufiventris Lepeletier, 1836 is a Brazilian native stingless bee that is part of a species complex known as the 'rufiventris group', making it difficult to distinguish between the different species. Populations in this group are facing a severe decline, leading to the risk of local extinction, and therefore, their conservation should be treated as a major concern. This study describes the first set of tri- and tetranucleotide microsatellite markers, using next-generation sequencing technology for use in the identification of genetic diversity and population structure in the 'rufiventris group'. A total of 16 microsatellite loci displayed polymorphism. Analysis of the whole data set (n = 50) detected 63 alleles in all loci, ranging from 2 to 7 with a mean of 3.9 alleles/locus. A genetic diversity analysis revealed high values for population differentiation estimates (FST = 0.252, RST = 0.317, and DEST = 0.284) between the Atlantic Forest, Cerrado, and Caatinga biomes. An additional evidence for genetic divergence among populations was also found in the 'rufiventris group'; these should be treated as separate conservation units or even as separate species. These microsatellite markers have demonstrated a strong potential for assessing population discrimination in this threatened stingless bee group.
| S-EPMC6955984 | biostudies-literature
Project description:The Bicolor Angelfish, Centropyge bicolor, is a tropical coral reef fish. It is named for its striking two-color body. However, a lack of high-quality genomic data means little is known about the genome of this species. Here, we present a chromosome-level C. bicolor genome constructed using Hi-C data. The assembled genome is 650 Mbp in size, with a scaffold N50 value of 4.4 Mbp, and a contig N50 value of 114 Kbp. Protein-coding genes numbering 21,774 were annotated. Our analysis will help others to choose the most appropriate de novo genome sequencing strategy based on resources and target applications. To the best of our knowledge, this is the first chromosome-level genome for the Pomacanthidae family, which might contribute to further studies exploring coral reef fish evolution, diversity and conservation.
| S-EPMC9650296 | biostudies-literature