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1.
mSystems ; 9(5): e0140523, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38557130

RESUMO

The gut microbiome affects the health status of the host through complex interactions with the host's intestinal wall. These host-microbiome interactions may spatially vary along the physical and chemical environment of the intestine, but these changes remain unknown. This study investigated these intricate relationships through a gene co-expression network analysis based on dual transcriptome profiling of different intestinal sites-cecum, transverse colon, and rectum-of the primate common marmoset. We proposed a gene module extraction algorithm based on the graph theory to find tightly interacting gene modules of the host and the microbiome from a vast co-expression network. The 27 gene modules identified by this method, which include both host and microbiome genes, not only produced results consistent with previous studies regarding the host-microbiome relationships, but also provided new insights into microbiome genes acting as potential mediators in host-microbiome interplays. Specifically, we discovered associations between the host gene FBP1, a cancer marker, and polysaccharide degradation-related genes (pfkA and fucI) coded by Bacteroides vulgatus, as well as relationships between host B cell-specific genes (CD19, CD22, CD79B, and PTPN6) and a tryptophan synthesis gene (trpB) coded by Parabacteroides distasonis. Furthermore, our proposed module extraction algorithm surpassed existing approaches by successfully defining more functionally related gene modules, providing insights for understanding the complex relationship between the host and the microbiome.IMPORTANCEWe unveiled the intricate dynamics of the host-microbiome interactions along the colon by identifying closely interacting gene modules from a vast gene co-expression network, constructed based on simultaneous profiling of both host and microbiome transcriptomes. Our proposed gene module extraction algorithm, designed to interpret inter-species interactions, enabled the identification of functionally related gene modules encompassing both host and microbiome genes, which was challenging with conventional modularity maximization algorithms. Through these identified gene modules, we discerned previously unrecognized bacterial genes that potentially mediate in known relationships between host genes and specific bacterial species. Our findings underscore the spatial variations in host-microbiome interactions along the colon, rather than displaying a uniform pattern throughout the colon.


Assuntos
Microbioma Gastrointestinal , Redes Reguladoras de Genes , Animais , Microbioma Gastrointestinal/genética , Callithrix/microbiologia , Interações entre Hospedeiro e Microrganismos/genética , Perfilação da Expressão Gênica/métodos , Transcriptoma , Intestinos/microbiologia , Algoritmos
2.
mSystems ; 7(5): e0052022, 2022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36005400

RESUMO

The intestinal microbiome is closely related to host health, and metatranscriptomic analysis can be used to assess the functional activity of microbiomes by quantifying microbial gene expression levels, helping elucidate the interactions between the microbiome and the environment. However, the functional changes in the microbiome along the host intestinal tract remain unknown, and previous analytical methods have limitations, such as potentially overlooking unknown genes due to dependence on existing databases. The objective of this study is to develop a computational pipeline combined with next-generation sequencing for spatial covariation analysis of the functional activity of microbiomes at multiple intestinal sites (biogeographic locations) within the same individual. This method reconstructs a reference metagenomic sequence across multiple intestinal sites and integrates the metagenome and metatranscriptome, allowing the gene expression levels of the microbiome, including unknown bacterial genes, to be compared among multiple sites. When this method was applied to metatranscriptomic analysis in the intestinal tract of common marmosets, a New World monkey, the reconstructed metagenome covered most of the expressed genes and revealed that the differences in microbial gene expression among the cecum, transverse colon, and feces were more dynamic and sensitive to environmental shifts than the abundances of the genes. In addition, metatranscriptomic profiling at three intestinal sites of the same individual enabled covariation analysis incorporating spatial relevance, accurately predicting the function of a total of 10,856 unknown genes. Our findings demonstrate that our proposed analytical method captures functional changes in microbiomes at the gene resolution level. IMPORTANCE We developed an analysis method that integrates metagenomes and metatranscriptomes from multiple intestinal sites to elucidate how microbial function varies along the intestinal tract. This method enables spatial covariation analysis of the functional activity of microbiomes and accurate identification of gene expression changes among intestinal sites, including changes in the expression of unknown bacterial genes. Moreover, we applied this method to the investigation of the common marmoset intestine, which is anatomically and pharmacologically similar to that of humans. Our findings indicate the expression pattern of the microbiome varies in response to changes in the internal environment along the intestinal tract, and this microbial change may affect the intestinal environment.


Assuntos
Microbioma Gastrointestinal , Microbiota , Animais , Humanos , Callithrix/genética , Microbiota/genética , Metagenoma , Intestinos , Microbioma Gastrointestinal/genética
3.
BMC Genomics ; 21(Suppl 3): 243, 2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-32241258

RESUMO

BACKGROUND: The common marmoset (Callithrix jacchus) is one of the most studied primate model organisms. However, the marmoset genomes available in the public databases are highly fragmented and filled with sequence gaps, hindering research advances related to marmoset genomics and transcriptomics. RESULTS: Here we utilize single-molecule, long-read sequence data to improve and update the existing genome assembly and report a near-complete genome of the common marmoset. The assembly is of 2.79 Gb size, with a contig N50 length of 6.37 Mb and a chromosomal scaffold N50 length of 143.91 Mb, representing the most contiguous and high-quality marmoset genome up to date. Approximately 90% of the assembled genome was represented in contigs longer than 1 Mb, with approximately 104-fold improvement in contiguity over the previously published marmoset genome. More than 98% of the gaps from the previously published genomes were filled successfully, which improved the mapping rates of genomic and transcriptomic data on to the assembled genome. CONCLUSIONS: Altogether the updated, high-quality common marmoset genome assembly provide improvements at various levels over the previous versions of the marmoset genome assemblies. This will allow researchers working on primate genomics to apply the genome more efficiently for their genomic and transcriptomic sequence data.


Assuntos
Callithrix/genética , Mapeamento Cromossômico/métodos , Genoma/genética , Animais , Biologia Computacional/métodos , Mapeamento de Sequências Contíguas/métodos , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Alinhamento de Sequência
4.
J Biosci Bioeng ; 128(6): 690-696, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31272833

RESUMO

Poly-γ-glutamic acid (γPGA) production by Bacillus subtilis is regulated by the quorum sensing system where DegQ transmits the cell density signal to a DNA-binding protein DegU. A mutation suppressing the γPGA-negative phenotype of degQ gene knock-out mutant (ΔdegQ) was identified through whole genome sequencing. The mutation conferred an amino acid substitution of Ser103 to phenylalanine (S103F) in yabJ that belongs to the highly conserved YjgF/YER057c/UK114 family. Genetic experiments including LacZ-fusion assay of γPGA synthetic operon confirmed that the suppressor mutation (yabJS103F) was responsible for the recovery of γPGA production. The yabJ itself was not essential for the γPGA production and the mutant allele enabled γPGA production of the ΔdegQ strain even in the presence of wild type yabJ. Thus, yabJS103F was a dominant positive allele. degU-lacZ fusion gene was hyper-expressed in cells carrying the yabJS103F, but disruption of yabJ did not affect the transcription level of the degU-lacZ. These observations suggested that YabJ acquired a function to stimulate expression of degU by the S103F mutation which is involved in the regulation of γPGA synthesis.


Assuntos
Bacillus subtilis/metabolismo , Proteínas de Bactérias/metabolismo , Mutação com Ganho de Função , Ácido Poliglutâmico/análogos & derivados , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Óperon , Ácido Poliglutâmico/biossíntese , Percepção de Quorum , Supressão Genética , Transativadores/metabolismo
5.
Sci Rep ; 8(1): 12994, 2018 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-30158594

RESUMO

Recent years have witnessed substantial progress in understanding tumor heterogeneity and the process of tumor progression; however, the entire process of the transition of tumors from a benign to metastatic state remains poorly understood. In the present study, we performed a prospective cancer genome-sequencing analysis by employing an experimental carcinogenesis mouse model of squamous cell carcinoma to systematically understand the evolutionary process of tumors. We surgically collected a part of a lesion of each tumor and followed the progression of these tumors in vivo over time. Comparative time-series analysis of the genomes of tumors with different fates, i.e., those that eventually metastasized and regressed, suggested that these tumors acquired and inherited different mutations. These findings suggest that despite the occurrence of an intra-tumor selection event for malignant alteration during the transformation from early- to late-stage papilloma, the fate determination of tumors might be determined at an even earlier stage.


Assuntos
Carcinogênese , Carcinoma de Células Escamosas/patologia , Genômica , Mutação , Neoplasias Cutâneas/patologia , Animais , Modelos Animais de Doenças , Estudos Longitudinais , Camundongos , Análise de Sequência de DNA , Fatores de Tempo
6.
PLoS One ; 12(11): e0188285, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29161291

RESUMO

High-throughput RNA sequencing technology is widely used to comprehensively detect and quantify cellular gene expression. Thus, numerous analytical methods have been proposed for identifying differentially expressed genes (DEGs) between paired samples such as tumor and control specimens, but few studies have reported methods for analyzing differential expression under multiple conditions. We propose a novel method, DEclust, for differential expression analysis among more than two matched samples from distinct tissues or conditions. As compared to conventional clustering methods, DEclust more accurately extracts statistically significant gene clusters from multi-conditional transcriptome data, particularly when replicates of quantitative experiments are available. DEclust can be used for any multi-conditional transcriptome data, as well as for extending any DEG detection tool for paired samples to multiple samples. Accordingly, DEclust can be used for a wide range of applications for transcriptome data analysis. DEclust is freely available at http://www.dna.bio.keio.ac.jp/software/DEclust.


Assuntos
Perfilação da Expressão Gênica/estatística & dados numéricos , Sequenciamento de Nucleotídeos em Larga Escala/estatística & dados numéricos , Software , Transcriptoma/genética , Análise por Conglomerados , Humanos
7.
Bioinformatics ; 32(12): i369-i377, 2016 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-27307639

RESUMO

MOTIVATION: Deep sequencing of the transcripts of regulatory non-coding RNA generates footprints of post-transcriptional processes. After obtaining sequence reads, the short reads are mapped to a reference genome, and specific mapping patterns can be detected called read mapping profiles, which are distinct from random non-functional degradation patterns. These patterns reflect the maturation processes that lead to the production of shorter RNA sequences. Recent next-generation sequencing studies have revealed not only the typical maturation process of miRNAs but also the various processing mechanisms of small RNAs derived from tRNAs and snoRNAs. RESULTS: We developed an algorithm termed SHARAKU to align two read mapping profiles of next-generation sequencing outputs for non-coding RNAs. In contrast with previous work, SHARAKU incorporates the primary and secondary sequence structures into an alignment of read mapping profiles to allow for the detection of common processing patterns. Using a benchmark simulated dataset, SHARAKU exhibited superior performance to previous methods for correctly clustering the read mapping profiles with respect to 5'-end processing and 3'-end processing from degradation patterns and in detecting similar processing patterns in deriving the shorter RNAs. Further, using experimental data of small RNA sequencing for the common marmoset brain, SHARAKU succeeded in identifying the significant clusters of read mapping profiles for similar processing patterns of small derived RNA families expressed in the brain. AVAILABILITY AND IMPLEMENTATION: The source code of our program SHARAKU is available at http://www.dna.bio.keio.ac.jp/sharaku/, and the simulated dataset used in this work is available at the same link. Accession code: The sequence data from the whole RNA transcripts in the hippocampus of the left brain used in this work is available from the DNA DataBank of Japan (DDBJ) Sequence Read Archive (DRA) under the accession number DRA004502. CONTACT: yasu@bio.keio.ac.jp SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Algoritmos , Sequenciamento de Nucleotídeos em Larga Escala , Análise por Conglomerados , Bases de Dados de Ácidos Nucleicos , RNA não Traduzido , Análise de Sequência de RNA , Software
8.
PLoS One ; 10(10): e0141369, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26505996

RESUMO

Bacillus subtilis is the main component in the fermentation of soybeans. To investigate the genetics of the soybean-fermenting B. subtilis strains and its relationship with the productivity of extracellular poly-γ-glutamic acid (γPGA), we sequenced the whole genome of eight B. subtilis stains isolated from non-salted fermented soybean foods in Southeast Asia. Assembled nucleotide sequences were compared with those of a natto (fermented soybean food) starter strain B. subtilis BEST195 and the laboratory standard strain B. subtilis 168 that is incapable of γPGA production. Detected variants were investigated in terms of insertion sequences, biotin synthesis, production of subtilisin NAT, and regulatory genes for γPGA synthesis, which were related to fermentation process. Comparing genome sequences, we found that the strains that produce γPGA have a deletion in a protein that constitutes the flagellar basal body, and this deletion was not found in the non-producing strains. We further identified diversity in variants of the bio operon, which is responsible for the biotin auxotrophism of the natto starter strains. Phylogenetic analysis using multilocus sequencing typing revealed that the B. subtilis strains isolated from the non-salted fermented soybeans were not clustered together, while the natto-fermenting strains were tightly clustered; this analysis also suggested that the strain isolated from "Tua Nao" of Thailand traces a different evolutionary process from other strains.


Assuntos
Bacillus subtilis/genética , Genoma Bacteriano , Glycine max/microbiologia , Ácido Poliglutâmico/análogos & derivados , Elementos de DNA Transponíveis/genética , Microbiologia de Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Ácido Poliglutâmico/genética , Ácido Poliglutâmico/metabolismo , Alimentos de Soja/microbiologia , Subtilisinas/genética , Tailândia
9.
PLoS One ; 9(10): e109999, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25329997

RESUMO

De novo microbial genome sequencing reached a turning point with third-generation sequencing (TGS) platforms, and several microbial genomes have been improved by TGS long reads. Bacillus subtilis natto is closely related to the laboratory standard strain B. subtilis Marburg 168, and it has a function in the production of the traditional Japanese fermented food "natto." The B. subtilis natto BEST195 genome was previously sequenced with short reads, but it included some incomplete regions. We resequenced the BEST195 genome using a PacBio RS sequencer, and we successfully obtained a complete genome sequence from one scaffold without any gaps, and we also applied Illumina MiSeq short reads to enhance quality. Compared with the previous BEST195 draft genome and Marburg 168 genome, we found that incomplete regions in the previous genome sequence were attributed to GC-bias and repetitive sequences, and we also identified some novel genes that are found only in the new genome.


Assuntos
Bacillus subtilis/genética , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Genes Bacterianos/genética
10.
J Biosci Bioeng ; 115(6): 654-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23318248

RESUMO

The ability to produce exoenzymes of a Bacillus subtilis natto starter strain was improved through selection of a rifampicin-resistant phenotype. Proteomic and zymographic analyses showed increased production of cellulolytic and proteolytic enzymes and decreased production of levansucrase. This mutant had a mutation (S487L) in the ß-subunit of the RNA polymerase.


Assuntos
Antibióticos Antituberculose/farmacologia , Bacillus subtilis/enzimologia , Celulases/biossíntese , Fermentação , Peptídeo Hidrolases/biossíntese , Rifampina/farmacologia , Alimentos de Soja , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/genética , Farmacorresistência Bacteriana , Espaço Extracelular/enzimologia , Fenótipo
11.
J Comp Neurol ; 509(3): 271-82, 2008 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-18473389

RESUMO

The nervous system of the brachiolaria larva of the starfish, Asterina pectinifera, was characterized using immunohistochemistry with the neuron-specific monoclonal antibodies 1E11 and 1F9 and an anti-serotonin antibody. The antigen recognized by 1F9 was determined by immunoprecipitation, peptide identification by mass spectrometry, and cDNA cloning as a novel START (steroidogenic acute regulatory protein [StAR]-related lipid transfer) domain-containing protein. Nerve cells are prominent in the brachiolar arms, ciliary bands, and adult rudiment. The brachiolar arms contain sensory-like nerve cells in the adhesive papillae, flask-shaped nerve cells in the adhesive disk, and bundles of fibers with branches interconnecting them. In the ciliary bands, nerve cells are interconnected with axon bundles along the ciliary bands and some neurons send fibers toward the oral and aboral epidermis. These neural components of the ciliary bands are regionally modified to form masses such as lateral and oral ganglia. The future aboral epidermis of the adult rudiment forms a nerve plexus with cell bodies enriched over spicules. Serotonergic nerve cell bodies are found throughout the nervous system except in the adhesive disk, the bipinnaria arms, and the adult rudiment. In addition, there are neural components in the esophagus and in the coelom where nerve fibers or bundles have distinct orientations with respect to the muscle fibers. The neuroanatomy of the brachiolaria suggests how it may function in controlling larval physiology and identifies intriguing problems on the origin of larval and adult nerves.


Assuntos
Asterina/anatomia & histologia , Gânglios dos Invertebrados/embriologia , Sistema Nervoso/embriologia , Animais , Western Blotting , Eletroforese em Gel de Poliacrilamida , Imuno-Histoquímica , Imunoprecipitação , Larva , Reação em Cadeia da Polimerase Via Transcriptase Reversa
12.
Int J Dev Biol ; 51(4): 345-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17554688

RESUMO

The planarian Dugesia ryukyuensis reproduces both asexually (fissiparous) and sexually (oviparous) and can switch from the asexual mode to the sexual mode. By feeding with mature Bdellocephala brunnea oviparous worms, the fissiparous worms, which do not possess sexual organs, can be converted to fully sexualized worms in a process termed sexualization. As sexualization proceeds, the sexual organs are formed uniformly and five stages (stages 15) of the process have been identified histologically. In order to clarify the sexualization process, we attempted to isolate the genes expressed specifically at stage 5 by the differential display method. We isolated five genes expressed in the testis and two genes expressed in the yolk gland, which is an organ specific to sexualized worms. By BLAST search, one of the testis-specific genes was coded as testis-specific alpha-tubulin and two yolk gland-specific genes are similar to ribose-phosphate pyrophosphokinase I and F-box/SPRY-domain protein 1. Drs1, Drs2 and Drs3 were expressed in spermatocytes and spermatids from the early stage of spermatogenesis and Drs4 and Drs5 were expressed in spermatogonia, spermatocytes and spermatids. These genes are useful markers for elucidating the sexualization process.


Assuntos
Genes de Helmintos , Ovário/metabolismo , Planárias/anatomia & histologia , Planárias/genética , Testículo/metabolismo , Animais , Feminino , Hibridização In Situ , Masculino , Dados de Sequência Molecular , Ovário/citologia , Espermátides/metabolismo , Espermatócitos/metabolismo , Espermatogênese , Espermatogônias/metabolismo
14.
Zygote ; 14(2): 133-41, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16719949

RESUMO

Asterosap, a group of equally active isoforms of sperm-activating peptides from the egg jelly of the starfish Asterias amurensis, functions as a chemotactic factor for sperm. It transiently increases the intracellular cGMP level of sperm, which in turn induces a transient elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)). Using a fluorescent Ca(2+)-sensitive dye, Fluo-4 AM, we measured the changes in sperm [Ca(2+)](i) in response to asterosap. KB-R7943 (KB), a selective inhibitor of Na(+)/Ca(2+) exchanger (NCX), significantly inhibited the asterosap-induced transient elevation of [Ca(2+)](i), suggesting that asterosap influences [Ca(2+)](i) through activation of a K+-dependent NCX (NCKX). An NCKX activity of starfish sperm also shows K(+) dependency like other NCKXs. Therefore, we cloned an NCKX from the starfish testes and predicted that it codes for a 616 amino acid protein that is a member of the NCKX family. Pharmacological evidence suggests that this exchanger participates in the asterosap-induced Ca(2+) entry into sperm.


Assuntos
Asterias/metabolismo , Cálcio/metabolismo , Líquido Intracelular/metabolismo , Trocador de Sódio e Cálcio/fisiologia , Espermatozoides/metabolismo , Sequência de Aminoácidos , Animais , Masculino , Dados de Sequência Molecular , Potássio/fisiologia
15.
Dev Genes Evol ; 212(12): 585-92, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12536322

RESUMO

We have investigated sexualization of asexual worms in the planarian Dugesia ryukyuensis. During sexualization there is a point from which an animal cannot return to the asexual state (point-of-no-return). To isolate the genes related to the point-of-no-return, we performed differential screening and isolated one novel gene that was expressed specifically in yolk glands of the worms after the point-of-no-return and named it Dryg. It encoded 655 amino acids with a predicted molecular mass of 79 kDa. We performed a series of experiments using Dryg as a molecular marker in the yolk gland. At first, we monitored how the yolk gland was formed during sexualization. The expression in sexualizing worms at stage 3 is limited to a single type of cell that has characteristics of neoblasts, the totipotent somatic cells; however, the expression is observed in the yolk gland in sexualized worms. Furthermore, we monitored yolk glands for expression during regeneration. The original yolk glands seem to disappear after ablation, then new yolk glands appeared along the ventral nerve cords. Because this expression pattern looks like that of sexualizing worms at stage 3, we speculate that yolk gland cells may differentiate from neoblasts during regeneration as observed during sexualization.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Genes de Helmintos , Planárias/genética , Planárias/fisiologia , Reprodução/fisiologia , Transcrição Gênica , Animais , Fatores Biológicos/farmacologia , Planárias/crescimento & desenvolvimento , Regeneração , Reprodução/efeitos dos fármacos , Reprodução Assexuada/efeitos dos fármacos , Reprodução Assexuada/fisiologia , Fatores de Tempo
16.
Integr Comp Biol ; 43(2): 242-6, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21680428

RESUMO

Many metazoans convert the reproductive modes presumably depending upon the environmental conditions and/or the phase of life cycle, but the mechanisms underlying the switching from asexual to sexual reproduction, and vice versa, remain unknown. We established an experimental system, using an integrative biology approach, to analyze the mechanism in the planarian, Dugesia ryukyuensis (Kobayashi et al., 1999). Worms of exclusively asexual clone (OH strain) of the species gradually develop ovaries, testes and other sexual organs, then copulate and eventually lay cocoons filled with fertilized eggs, if they are fed with sexually mature worms of Bdellocephala brunnea (an exclusively oviparous species). This suggests the existence of a sexualizing substance(s) in sexually mature worms. Random inbreeding of experimentally sexualized worms (acquired sexuals) produces an F1 population of spontaneous sexuals (innate sexuals) and asexuals in a ratio of approximately 2:1. All regenerants from various portions of innate sexuals become sexuals. In the case of acquired sexuals, head fragments without sexual organs regenerated into asexuals though regenerants from other portions became sexuals. Thus, we conclude that neoblasts, the totipotent stem cells in the planarians, of acquired sexuals remain "asexual" and the worms require external supply of a sexualizing substance for the differentiation of sexual organs and gametes. On the other hand, some, if not all, neoblasts in innate sexuals are somehow "sexual" and do not require external supply of a sexualizing substance for the eventual differentiation of themselves and/or other neoblasts into sexual organs and gametes. It is also shown that sexuality in acquired sexuals is maintained by the putative sexualizing substance(s) of their own. The sexualization is closely coupled with cessation of fission, and the worms seem to have an unknown way of controlling the karyotype. Our integrative approach integrates multiple fields of study, including classic breeding, regeneration, and genetics experiments, as well as karyotyping, and biochemical and molecular biological analyses; none of which would have revealed much about the intricate mechanisms that regulate sex and fission in these animals.

17.
Zoolog Sci ; 19(6): 667-72, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12130794

RESUMO

Asexual worms of an exclusively fissiparous strain (the OH strain) of the planarian Dugesia ryukyuensis keep developing hermaphroditic reproductive organs and eventually undergo sexual reproduction instead of asexual reproduction, namely fission, if they are fed with sexually mature worms of an exclusively oviparous planarian, Bdellocephala brunnea, suggesting that the sexually mature worms has a sexualizing substance(s). The fully sexualized worms no longer need the feeding on sexual worms to maintain the sexuality. Here, we demonstrate that the sexualized worms produce enough of their own sexualizing substance similar to that contained in B. brunnea. In case of surgical ablation of the sexualized worms, the fragments with sexual organs regenerate to become sexual, while those without sexual organs, namely head fragments, regenerate to return to the asexual state. The asexual regenerants from the sexualized worms are also fully sexualized by being fed with B. brunnea. Additionally, it was reported that head region in sexually mature worms lacks the putative sexualizing substance necessary for complete sexualization (Sakurai, 1981). These results suggest that the fragments without sexual organ lack enough of an amount of the putative sexualizing substance and the sexuality is maintained by the sexualizing substance contained in the sexualized worms.


Assuntos
Planárias/fisiologia , Reprodução Assexuada/fisiologia , Reprodução/fisiologia , Animais , Fatores Biológicos/administração & dosagem , Fatores Biológicos/metabolismo , Fatores Biológicos/farmacologia , Morfogênese/efeitos dos fármacos , Planárias/efeitos dos fármacos , Planárias/crescimento & desenvolvimento , Planárias/metabolismo , Regeneração , Reprodução/efeitos dos fármacos , Reprodução Assexuada/efeitos dos fármacos
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