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Journal of Fungi (Basel, Switzerland) Aug 2021is recognized as one of the most important oomycetes pests of salmon and trout species. The amplified fragment length polymorphism (AFLP) and method sequence data of...
is recognized as one of the most important oomycetes pests of salmon and trout species. The amplified fragment length polymorphism (AFLP) and method sequence data of the internal transcribed spacer (ITS) were used to study the genetic diversity and relationships of spp. collected from Canada, Chile, Japan, Norway and Scotland. AFLP analysis of 37 spp. isolates using six primer combinations gave a total of 163 clear polymorphic bands. Bayesian cluster analysis using genetic similarity divided the isolates into three main groups, suggesting that there are genetic relationships among the isolates. The unweighted pair group method with arithmetic mean (UPGMA) and principal coordinate analysis (PCO) confirmed the pattern of the cluster analyses. ITS analyses of 48 sequences resulted in five well-defined clades. Analysis of molecular variance (AMOVA) revealed greater variation within countries (91.01%) than among countries (8.99%). We were able to distinguish the isolates according to their species, ability to produce oogonia with and without long spines on the cysts and their ability to or not to cause mortality in salmonids. AFLP markers and ITS sequencing data obtained in the study, were found to be an efficient tool to characterize the genetic diversity and relationships of spp. The comparison of AFLP analysis and ITS sequence data using the Mantel test showed a very high and significant correlation ( = 0.8317).
PubMed: 34575751
DOI: 10.3390/jof7090713 -
Development (Cambridge, England) Oct 2021Emerging evidence suggests that ribosome heterogeneity may have important functional consequences in the translation of specific mRNAs within different cell types and...
Emerging evidence suggests that ribosome heterogeneity may have important functional consequences in the translation of specific mRNAs within different cell types and under various conditions. Ribosome heterogeneity comes in many forms, including post-translational modification of ribosome proteins (RPs), absence of specific RPs and inclusion of different RP paralogs. The Drosophila genome encodes two RpS5 paralogs: RpS5a and RpS5b. While RpS5a is ubiquitously expressed, RpS5b exhibits enriched expression in the reproductive system. Deletion of RpS5b results in female sterility marked by developmental arrest of egg chambers at stages 7-8, disruption of vitellogenesis and posterior follicle cell (PFC) hyperplasia. While transgenic rescue experiments suggest functional redundancy between RpS5a and RpS5b, molecular, biochemical and ribo-seq experiments indicate that RpS5b mutants display increased rRNA transcription and RP production, accompanied by increased protein synthesis. Loss of RpS5b results in microtubule-based defects and in mislocalization of Delta and Mindbomb1, leading to failure of Notch pathway activation in PFCs. Together, our results indicate that germ cell-specific expression of RpS5b promotes proper egg chamber development by ensuring the homeostasis of functional ribosomes.
Topics: Animals; Drosophila Proteins; Drosophila melanogaster; Female; Infertility; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Mutation; Oogenesis; Oogonia; Ovarian Follicle; Protein Transport; RNA, Ribosomal; Receptors, Notch; Signal Transduction
PubMed: 34495316
DOI: 10.1242/dev.199511 -
Pathogens (Basel, Switzerland) Aug 2021Alder dieback remains a major problem in European alder stands and its spread continues to threaten their existence. The causal agent of this disease is the so-called...
Alder dieback remains a major problem in European alder stands and its spread continues to threaten their existence. The causal agent of this disease is the so-called alder species complex, which includes the hybrid × and its parental species and . Little is known about the survival of these species in alder. The aim of our investigations was to find out whether, and if so where, the pathogen survives. The subject of these studies was alder roots. Therefore, artificial infection studies and histological studies with . × and were carried out on seedlings of black alder (). These histological studies revealed oogonia and oospores of . × and in different parts of the root tissue.
PubMed: 34451441
DOI: 10.3390/pathogens10080977 -
Zoological Studies 2021This study evaluates the gonadal histology of present in the upper Paraná River floodplain and samples of limnological variables to understand its reproductive cycle....
This study evaluates the gonadal histology of present in the upper Paraná River floodplain and samples of limnological variables to understand its reproductive cycle. was monitored monthly from December 2013 to February 2015. Spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa were identified in the male follicles of the hermaphrodites. Oogonia, oogonial nests, previtellogenic oocytes, early vitellogenic oocytes, middle vitellogenic oocytes and full-grown vitellogenic oocytes were identified in the female follicles of the hermaphrodites and females. The reproductive phases were described as developing, active spawning/sperm releasing, regression and regeneration. Higher values of temperature, dissolved oxygen, total nitrogen and total phosphorous were identified during flood periods, while higher values of pH and conductivity were obtained during dry periods. The species either does not reproduce or reduces the intensity of reproduction in cold months, with the sex ratio not differing significantly between hermaphrodites and females with regard to month and reproductive phase. Thus, reproduction is synchronized with the flood period and its limnological characteristics and when the increase in connectivity between floodplain environments facilitates the larval dispersion of this non-native species into other environments.
PubMed: 34322169
DOI: 10.6620/ZS.2021.60-03 -
Proceedings of the National Academy of... Jul 2021Germ cells form the basis for sexual reproduction by producing gametes. In ovaries, primordial germ cells exit the cell cycle and the pluripotency-associated state,...
Germ cells form the basis for sexual reproduction by producing gametes. In ovaries, primordial germ cells exit the cell cycle and the pluripotency-associated state, differentiate into oogonia, and initiate meiosis. Despite the importance of germ cell differentiation for sexual reproduction, signaling pathways regulating their fate remain largely unknown. Here, we show in mouse embryonic ovaries that germ cell-intrinsic β-catenin activity maintains pluripotency and that its repression is essential to allow differentiation and meiosis entry in a timely manner. Accordingly, in β-catenin loss-of-function and gain-of-function mouse models, the germ cells precociously enter meiosis or remain in the pluripotent state, respectively. We further show that interaction of β-catenin and the pluripotent-associated factor POU5F1 in the nucleus is associated with germ cell pluripotency. The exit of this complex from the nucleus correlates with germ cell differentiation, a process promoted by the up-regulation of , a negative regulator of WNT/β-catenin signaling. Together, these data identify the molecular basis of the transition from primordial germ cells to oogonia and demonstrate that β-catenin is a central gatekeeper in ovarian differentiation and gametogenesis.
Topics: Animals; Cell Differentiation; Female; Germ Cells; Mice; Mice, Inbred C57BL; Octamer Transcription Factor-3; Pluripotent Stem Cells; Wnt Proteins; beta Catenin
PubMed: 34301885
DOI: 10.1073/pnas.2023376118 -
Frontiers in Cell and Developmental... 2021The human germ cell lineage originates from primordial germ cells (PGCs), which are specified at approximately the third week of development. Our understanding of the...
The human germ cell lineage originates from primordial germ cells (PGCs), which are specified at approximately the third week of development. Our understanding of the signaling pathways that control this event has significantly increased in recent years and that has enabled the generation of PGC-like cells (PGCLCs) from pluripotent stem cells . However, the signaling pathways that drive the transition of PGCs into gonia (prospermatogonia in males or premeiotic oogonia in females) remain unclear, and we are presently unable to mimic this step in the absence of gonadal tissue. Therefore, we have analyzed single-cell transcriptomics data of human fetal gonads to map the molecular interactions during the sex-specific transition from PGCs to gonia. The CellPhoneDB algorithm was used to identify significant ligand-receptor interactions between germ cells and their sex-specific neighboring gonadal somatic cells, focusing on four major signaling pathways WNT, NOTCH, TGFβ/BMP, and receptor tyrosine kinases (RTK). Subsequently, the expression and intracellular localization of key effectors for these pathways were validated in human fetal gonads by immunostaining. This approach provided a systematic analysis of the signaling environment in developing human gonads and revealed sex-specific signaling pathways during human premeiotic germ cell development. This work serves as a foundation to understand the transition from PGCs to premeiotic oogonia or prospermatogonia and identifies sex-specific signaling pathways that are of interest in the step-by-step reconstitution of human gametogenesis
PubMed: 34222234
DOI: 10.3389/fcell.2021.661243 -
Plant Disease Jul 2021Hiroshima Prefecture has the highest production area of hydroponically grown Welsh onions ( L.) in Japan. Since the cultivation began in 1988, root rot (Fig. 1A)...
Hiroshima Prefecture has the highest production area of hydroponically grown Welsh onions ( L.) in Japan. Since the cultivation began in 1988, root rot (Fig. 1A) followed by leaf browning (Fig. 1B) has caused significant economic losses. Approximately 80% (loss of 45 million JPY) of plant loss occurred from May to Sep 2009 (Shimizu, unpublished), and the disease was observed again in 2020. Diseased Welsh onions (five to six leaf stage) were collected in 2009. Abundant nonseptate hyphae of -like organisms were observed in the rotted roots (Fig. 1C). Disinfected symptomatic tissue samples were placed on NARF medium (Morita and Tojo 2007) and incubated at 25°C for 3 to 7 days. Six -like organisms were isolated, and their morphological features on a grass blade culture, potato carrot agar (PCA) (van der Plaats-Niterink 1981), cornmeal agar (CMA) and V8 juice agar (Miller 1955) were examined. Hyphal growth rates from 1-46°C were measured by culturing on PCA. The ribosomal internal transcribed spacer (ITS) regions and mitochondrial of the isolates were amplified and sequenced according to Ueta and Tojo (2016). All six isolates obtained showed similar morphology, hyphal growth rates, and sequences of ITS and . Detailed descriptions are provided here for the representative isolate 72 (MAFF246451). The isolate produced asexual structures but did not form sexual structures, including oogonia, antheridia, and oospores on all the media used. Hyphae were up to 6.8 μm wide. Appressoria were knob-like terminations (Fig. 1D). Sporangia were filamentous and indistinguishable from the hyphae. Zoospores (Fig. 1E) were formed at 5-25°C. The diameter of encysted zoospores ranged 7.4-10.1 (av. 8.9) μm (Fig. 1F). Cardinal temperatures for hyphal growth on PCA were 5°C min, 28-31°C opt, and 35°C max. The daily growth rate at 25°C was 15.0 mm per day. The sequence analysis of all isolates, including isolate 72 (GenBank ac nos AB700596 for ITS, LC630955 for ) showed the present isolates belonged to Cluster B2a (Robideau et al. 2011) (Fig. 2). Based on these features, the six isolates were identified as Cluster B2a sp. In the inoculation test, isolate 72 was cultured on CMA at 25°C for 5 days. Mycelium disks (5 mm diam) obtained from the culture were placed on the primary roots of 8-day-old Welsh onion seedlings (cv Koutou), which were grown at a density of six plants on rock wool cubes moistened with tap water in a 50 mL plastic pot. The inoculated and non-inoculated plants were grown at 28°C for 7 days in a growth chamber. The experiment was repeated twice using three pots per replication. The plants inoculated with isolate 72 wilted, and their roots rotted 7 days after inoculation. No disease was found observed on the non-inoculated plants. The isolate of Cluster B2a sp. was consistently re-isolated from the diseased plants, thus, fulfilling Koch's postulates. Pythium Cluster B2a sp. causing stem rot on lettuce has been recorded in Italy (Garibaldi et al. 2017). To our knowledge, this is the first report of Cluster B2a sp. on Welsh onions. Since significant losses to root rot of Welsh onion have occurred in Japan, identification of the causal organism will enable the development of management practices to reduces losses.
PubMed: 34213971
DOI: 10.1094/PDIS-06-21-1211-PDN -
Cells & Development Sep 2021P-Element-induced wimpy testis (Piwi) subfamily proteins form complexes that bind to Piwi-interacting RNA. This interaction is crucial for stem cell regulation and...
P-Element-induced wimpy testis (Piwi) subfamily proteins form complexes that bind to Piwi-interacting RNA. This interaction is crucial for stem cell regulation and formation, maintenance of germline stem cells, and gametogenesis in several metazoans. Planarians are effective models for studying stem cells. In the planarian Dugesia ryukyuensis, DrPiwi-1 is essential for the development of germ cells, but not somatic cells and sexual organs. DrPiwi-2 is indispensable for regeneration. In this study, we aimed to investigate the effects of Piwi on the differentiation of germ cells using monoclonal antibodies against DrPiwi-1 and DrPiwi-2. DrPiwi-1 and DrPiwi-2 co-localized more in immature germ cells than in mature germ cells in the ovary. DrPiwi-1 was found in the cytoplasm of early oogonia as undifferentiated germ cells, whereas DrPiwi-2 was found to localize not only in the nuclei but also in the cytoplasm of early oogonia. In descendant germ cells (oocytes), DrPiwi-2 was not present in the cytoplasm, but was strongly detected in the nucleolus. Moreover, we found that DrPiwi-1 forms a complex with DrPiwi-2. The cause of DrPiwi-1 depletion may be the severe reduction in the DrPiwi-2 level in the cytoplasm of oogonia. These results suggest that the formation of the DrPiwi-1 and DrPiwi-2 complex in the cytoplasm of oogonia is essential for oocyte differentiation. Our findings support the conclusion that DrPiwi-1 forms a complex with DrPiwi-2 in the cytoplasm of undifferentiated germ cells, and it signifies the start of gametogenesis. In contrast, in the testes, Drpiwi-1 was found in undifferentiated germ cells (spermatogonia), whereas DrPiwi-2 was found in descendant germ cells (spermatocytes). The process of germ cell differentiation from adult stem cells in planarians may be regulated in different ways in female and male germ lines by the Piwi family.
Topics: Animals; Cell Differentiation; Cytoplasm; Female; Male; Oocytes; Oogonia; Ovary; Planarians; Proteins; Testis
PubMed: 34171535
DOI: 10.1016/j.cdev.2021.203710 -
Nature Communications Jun 2021In the Caenorhabditis elegans germline, thousands of mRNAs are concomitantly expressed with antisense 22G-RNAs, which are loaded into the Argonaute CSR-1. Despite their...
In the Caenorhabditis elegans germline, thousands of mRNAs are concomitantly expressed with antisense 22G-RNAs, which are loaded into the Argonaute CSR-1. Despite their essential functions for animal fertility and embryonic development, how CSR-1 22G-RNAs are produced remains unknown. Here, we show that CSR-1 slicer activity is primarily involved in triggering the synthesis of small RNAs on the coding sequences of germline mRNAs and post-transcriptionally regulates a fraction of targets. CSR-1-cleaved mRNAs prime the RNA-dependent RNA polymerase, EGO-1, to synthesize 22G-RNAs in phase with translating ribosomes, in contrast to other 22G-RNAs mostly synthesized in germ granules. Moreover, codon optimality and efficient translation antagonize CSR-1 slicing and 22G-RNAs biogenesis. We propose that codon usage differences encoded into mRNA sequences might be a conserved strategy in eukaryotes to regulate small RNA biogenesis and Argonaute targeting.
Topics: Animals; Argonaute Proteins; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Catalysis; Codon Usage; Cytosol; Mutation; Oogonia; Protein Biosynthesis; RNA Interference; RNA, Messenger; RNA, Small Interfering; RNA-Dependent RNA Polymerase; Ribosomes
PubMed: 34108460
DOI: 10.1038/s41467-021-23615-w -
Plant Disease Jun 2021In Aug 2019, approximately 10% of mung bean plants at the experimental farm of the Jiangsu Academy of Agricultural Science (32.03 N; 118.88 E) showed symptoms of...
In Aug 2019, approximately 10% of mung bean plants at the experimental farm of the Jiangsu Academy of Agricultural Science (32.03 N; 118.88 E) showed symptoms of stunting and wilting. Brown and water-soaked stem lesions were often observed at the base of the diseased plants. In severe cases, the plants collapsed and cumulous aerial mycelia were visible on the basal stem surface (Figure S1 A). To identify the causal agent, a total of 20 tissue fragments (5 mm long) were excised from roots and basal stems of five symptomatic plants. The fragments were surface sterilized in 2% sodium hypochlorite solution then plated on 2.5% potato dextrose agar (PDA) plates containing 10 μg/mL pimaricin, 100 μg/mL ampicillin, 10 μg/mL rifampicin, and 10 μg/mL pentachloronitrobenzene (PARP; Beckerman et al. 2017). After 3-4 days incubation at 25C in dark, 14 colonies with white and cumulous mycelia grew from the tissue pieces (named as JS19-1 to JS19-14). JS19-1 and JS19-2 were purified by hyphal tipping, then grown on PDA medium for 7 days for morphological observation using a compound microscope (Figure S1 B, C). Width of coenocytic hyphae ranged from 3.7 to 8.9 (avg. 6.1, n=20) μm. Terminal oogonia were globose and with a diameter of 13.8 to 25.8 (avg. 22, n=20) μm. Antheridia were barrel-shaped, and mostly intercalary, sometimes terminal. Most of antheridia were diclinous, with 6.2 to 12.5 (avg. 9.3, n=20) μm in width and 7.6 to 15.3 (avg. 12.8, n=20) μm in length. Oogonia were fertilized with one or two (rare) antheridia. Oospores were aplerotic, 10.1 to 23.5 (avg. 20.4, n=20) μm in diameter. Sporangia had terminal inflated hyphal branches (Figure S1 D, E). The two isolates were preliminary identified as . For molecular identification, the sequences of internal transcribed spacer (ITS) rDNA, cytochrome oxidase subunit I (CoxI) (Robideau et al. 2011), and β-tubulin (Kroon et al. 2004) of JS19-1 were detected, and deposited in GenBank (MT949538, MT949539 and MT949540). The ITS and CoxI sequences were identical with CBS28779 ITS (759/759 bp, HQ643439.1) and PYT01 CoxI (640/640 bp, MH760243.1) respectively, the β-tubulin sequence showed 99% (830/840 bp) similarity of P2 (AY564048.1). Thus, JS19-1 was confirmed as . To fulfill Koch's postulates, the pathogenicity of JS19-1 was tested using the procedure of Kiyoshi et al. (2021) with some modifications. Barley grains infested with JS19-1 were as inoculum and thoroughly mixed with potting mixture at a rate of 10% in volume. Six mung bean seeds were sown per pot and then grown in a greenhouse. Potting mixture with no inoculum was used as control. Three pots of replicate plants used for inoculation and control. After 3 weeks, emergence in the inoculated pots was 33% and symptoms of stunting and root rot similar to those in field were observed, while control plants were asymptomatic (FigureS1 F, G). was successfully reisolated from symptomatic plants of both methods. The pathogenicity tests were repeated twice. causes seed rot, pre- and postemergence damping-off, or stem/root rot of a wide range of industrial crops and vegetables (Liu et al, 2018). To our knowledge, this is the first report of causing disease on mung bean in China. Since (Sun et al, 2020) and (Yan et al, 2021) have been reported causing mung bean root rot, integrated disease management should be adopted to reduce damage.
PubMed: 34077250
DOI: 10.1094/PDIS-02-21-0297-PDN