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91.
Daniela Pica Aline Tribollet Stjepko Golubic Marzia Bo Cristina Gioia Di Camillo Giorgio Bavestrello 《Marine Biology Research》2016,12(6):573-582
Microboring or euendolithic microorganisms, which colonize and penetrate various carbonate substrates, are abundant in coral reef ecosystems and play a major role in reef carbonate dissolution. A few studies reported the presence of euendoliths in stylasterid coral skeletons but the biological identity, distribution and abundance of these microorganisms remain largely unknown. Observations of over 100 stylasterid colonies, collected in the Indo-Pacific area, revealed for the first time that the association between these corals and euendolith organisms appears to be quite common in shallow tropical waters. The most abundant euendolith was identified as a cryptic stage in the development of the rhodophyte Porphyra (Conchocelis stage). The euendoliths were observed in the skeletons of seven species of three genera (four Stylaster, two Distichopora and one Lepidotheca). The presence of euendoliths inside skeletons conferred a particular colour to the studied stylasterid corals. Distribution and abundance of microborings varied significantly among stylasterid species and among branches of a single colony and so did the colour of their skeletons. Colonization of skeletons and the associated colour distribution were almost uniform in some stylasterids, forming an upward gradually diminishing or sharply limited gradient. This study shows that patterns of euendolith colonization and growth in stylasterid skeletons may depend on the stage of the euendolith development as well as on their environmental requirements such as light exposure. 相似文献
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Hox genes are a remarkable example of conservation in animal development and their nested expression along the head‐to‐tail axis orchestrates embryonic patterning. Early in vertebrate history, two duplications led to the emergence of four Hox clusters (A‐D) and redundancy within paralog groups has been partially accommodated with gene losses. Here we conduct an inventory of squamate Hox genes using the genomes of 10 lizard and 7 snake species. Although the HoxC1 gene has been hypothesized to be lost in the amniote ancestor, we reveal that it is retained in lizards. In contrast, all snakes lack functional HoxC1 and ‐D12 genes. Varying levels of degradation suggest differences in the process of gene loss between the two genes. The vertebrate HoxC1 gene is prone to gene loss and its functional domains are more variable than those of other Hox1 genes. We describe for the first time the HoxC1 expression patterns in tetrapods. HoxC1 is broadly expressed during development in the diencephalon, the neural tube, dorsal root ganglia, and limb buds in two lizard species. Our study emphasizes the value of revisiting Hox gene repertoires by densely sampling taxonomic groups and its feasibility owing to growing sequence resources in evaluating gene repertoires across taxa. 相似文献
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Ran Zuo Aline de Oliveira Enrica Bullita Maria Ines Torino Kaylie A. Padgett-Pagliai Christopher L. Gardner Natalie A. Harrison Danilo da Silva Marcelo L. Merli Claudio F. Gonzalez Graciela L. Lorca 《Environmental microbiology》2019,21(12):4822-4835
Liberibacter asiaticus is the prevalent causative pathogen of Huanglongbing or citrus greening disease, which has resulted in a devastating crisis in the citrus industry. A thorough understanding of this pathogen's physiology and mechanisms to control cell survival is critical in the identification of therapeutic targets. YbeY is a highly conserved bacterial RNase that has been implicated in multiple roles. In this study, we evaluated the biochemical characteristics of the L. asiaticus YbeY (CLIBASIA_01560) and assessed its potential as a target for antimicrobials. YbeYLas was characterized as an endoribonuclease with activity on 3′ and 5′ termini of 16S and 23S rRNAs, and the capacity to suppress the E. coli ΔybeY phenotype. We predicted the YbeYLas protein:ligand interface and subsequently identified a flavone compound, luteolin, as a selective inhibitor. Site-directed mutagenesis was subsequently used to identify key residues involved in the catalytic activity of YbeYLas. Further evaluation of naturally occurring flavonoids in citrus trees indicated that both flavones and flavonols had potent inhibitory effects on YbeYLas. Luteolin was subsequently examined for efficacy against L. asiaticus in Huanglongbing-infected citrus trees, where a significant reduction in L. asiaticus gene expression was observed. 相似文献
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Natalie Groves Imogen OKeeffe Wendy Lee Alexandra Toft Daniel Blackmore Saurabh Bandhavkar Elizabeth J. Coulson Perry F. Bartlett Dhanisha J. Jhaveri 《Developmental neurobiology》2019,79(9-10):868-879
Brain‐derived neurotrophic factor (BDNF) signaling plays a major role in the regulation of hippocampal neurogenesis in the adult brain. While the majority of studies suggest that this is due to its effect on the survival and differentiation of newborn neurons, it remains unclear whether this signaling directly regulates neural precursor cell (NPC) activity and which of its two receptors, TrkB or the p75 neurotrophin receptor (p75NTR) mediates this effect. Here, we examined both the RNA and protein expression of these receptors and found that TrkB but not p75NTR receptors are expressed by hippocampal NPCs in the adult mouse brain. Using a clonal neurosphere assay, we demonstrate that pharmacological blockade of TrkB receptors directly activates a distinct subpopulation of NPCs. Moreover, we show that administration of ANA‐12, a TrkB‐selective antagonist, in vivo either by systemic intraperitoneal injection or by direct infusion within the hippocampus leads to an increase in the production of new neurons. In contrast, we found that NPC‐specific knockout of p75NTR had no effect on the proliferation of NPCs and did not alter neurogenesis in the adult hippocampus. Collectively, these results demonstrate a novel role of TrkB receptors in directly regulating the activity of a subset of hippocampal NPCs and suggest that the transient blockade of these receptors could be used to enhance adult hippocampal neurogenesis. 相似文献
99.
Elvita Eglite Martin Graeve Jrg Dutz Dirk Wodarg Iris Liskow Detlef Schulz‐Bull Natalie Loick‐Wilde 《Ecology and evolution》2019,9(17):9916-9934
Increasing sea surface temperatures (SST) and blooms of lipid‐poor, filamentous cyanobacteria can change mesozooplankton metabolism and foraging strategies in marine systems. Lipid shortage and imbalanced diet may challenge the build‐up of energy pools of lipids and proteins, and access to essential fatty acids (FAs) and amino acids (AAs) by copepods. The impact of cyanobacterial blooms on individual energy pools was assessed for key species temperate Temora longicornis and boreal Pseudo‐/Paracalanus spp. that dominated field mesozooplankton communities isolated by seasonal stratification in the central Baltic Sea during the hot and the cold summer. We looked at (a) total lipid and protein levels, (b) FA trophic markers and AA composition, and (c) compound‐specific stable carbon isotopes (δ13C) in bulk mesozooplankton and in a subset of parameters in particulate organic matter. Despite lipid‐poor cyanobacterial blooms, the key species were largely able to cover both energy pools, yet a tendency of lipid reduction was observed in surface animals. Omni‐ and carnivory feeding modes, FA trophic makers, and δ13C patterns in essential compounds emphasized that cyanobacterial FAs and AAs have been incorporated into mesozooplankton mainly via feeding on mixo‐ and heterotrophic (dino‐) flagellates and detrital complexes during summer. Foraging for essential highly unsaturated FAs from (dino‐) flagellates may have caused night migration of Pseudo‐/Paracalanus spp. from the deep subhalocline waters into the upper waters. Only in the hot summer (SST>19.0°C) was T. longicornis submerged in the colder subthermocline water (~4°C). Thus, the continuous warming trend and simultaneous feeding can eventually lead to competition on the preferred diet by key copepod species below the thermocline in stratified systems. A comparison of δ13C patterns of essential AAs in surface mesozooplankton across sub‐basins of low and high cyanobacterial biomasses revealed the potential of δ13C‐AA isoscapes for studies of commercial fish feeding trails across the Baltic Sea food webs. 相似文献