Patterning and cell differentiation in Hydra: novel genes and the limits to conservation

2002 ◽  
Vol 80 (10) ◽  
pp. 1670-1677 ◽  
Author(s):  
Thomas C.G Bosch ◽  
Konstantin Khalturin

In the last few years more than 100 genes have been identified from Hydra, and well over 80 have been characterized. Since most genes are homologs of genes found in bilaterians, the genetic mechanisms for axial patterning and cell differentiation are evolutionarily conserved. This constitutes something of a paradox. If key developmental-control genes are the same in Hydra and all other organisms, how does one account for the marked differences in development and morphology of the different animal groups? How are taxon-specific features encoded? To examine whether in Hydra, in addition to conserved mechanisms, there are genetic features that control uniquely taxon-specific (Hydra/Hydrozoa/Cnidaria) aspects, we used an experimental strategy that does not require sequence data from related taxa. By means of this unbiased ("knowledge-independent") approach we have identified genes from Hydra encoding signal molecules and effector genes with no sequence similarity to genes in other organisms. When tested functionally, the novel genes were found to be essential for axial patterning and differentiation of Hydra-specific characteristics. Experimental analysis of the cis-regulatory apparatus of these novel genes reveals target sites for novel trans-acting factors. The use of unbiased screening approaches for several other organisms also reveals a large number of novel and taxon-specific genes of as yet unknown function. Thus, comparative data alone may not be sufficient for gaining a full understanding of the development of taxon-specific characteristics.

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1036
Author(s):  
Ajani Athukorala ◽  
Jade K. Forwood ◽  
David N. Phalen ◽  
Subir Sarker

Wild birds harbour a large number of adenoviruses that remain uncharacterised with respect to their genomic organisation, diversity, and evolution within complex ecosystems. Here, we present the first complete genome sequence of an atadenovirus from a passerine bird that is tentatively named Passerine adenovirus 1 (PaAdV-1). The PaAdV-1 genome is 39,664 bp in length, which was the longest atadenovirus to be sequenced, to the best of our knowledge, and contained 42 putative genes. Its genome organisation was characteristic of the members of genus Atadenovirus; however, the novel PaAdV-1 genome was highly divergent and showed the highest sequence similarity with psittacine adenovirus-3 (55.58%). Importantly, PaAdV-1 complete genome was deemed to contain 17 predicted novel genes that were not present in any other adenoviruses sequenced to date, with several of these predicted novel genes encoding proteins that harbour transmembrane helices. Subsequent analysis of the novel PaAdV-1 genome positioned phylogenetically to a distinct sub-clade with all others sequenced atadenoviruses and did not show any obvious close evolutionary relationship. This study concluded that the PaAdV-1 complete genome described here is not closely related to any other adenovirus isolated from avian or other natural host species and that it should be considered a separate species.


2006 ◽  
Vol 56 (4) ◽  
pp. 821-826 ◽  
Author(s):  
Hanno Biebl ◽  
Brian J. Tindall ◽  
Rüdiger Pukall ◽  
Heinrich Lünsdorf ◽  
Martin Allgaier ◽  
...  

Within a collection of marine strains that were shown to contain the photosynthesis reaction-centre genes pufL and pufM, a novel group of alphaproteobacteria was found and was characterized phenotypically. The 16S rRNA gene sequence data suggested that the strains belonged to the order Rhizobiales and were closest (98·5 % sequence similarity) to the recently described species Hoeflea marina. The cells contained bacteriochlorophyll a and a carotenoid, presumably spheroidenone, in small to medium amounts. Cells of the novel strains were small rods and were motile by means of single polarly inserted flagella. Good growth occurred in complex media with 0·5–7·0 % sea salts, at 25–33 °C (optimum, 31 °C) and at pH values in the range 6–9. With the exception of acetate and malate, organic carbon sources tested supported poor growth or no growth at all. Growth factors were required; these were provided by small amounts of yeast extract, but not by standard vitamin solutions. Growth occurred under aerobic to microaerobic conditions, but not under anaerobic conditions, either in the dark or light. Nitrate was not reduced. Photosynthetic pigments were formed at low to medium salt concentrations, but not at the salt concentration of sea water (3·5 %). On the basis of smaller cell size, different substrate utilization profile and photosynthetic pigment content, the novel strains can be classified as representatives of a second species of Hoeflea, for which the name Hoeflea phototrophica sp. nov. is proposed. The type strain of Hoeflea phototrophica sp. nov. is DFL-43T (=DSM 17068T=NCIMB 14078T).


2007 ◽  
Vol 19 (8) ◽  
pp. 967 ◽  
Author(s):  
Anna E. Zielak ◽  
Niamh Forde ◽  
Stephan D. E. Park ◽  
Fiona Doohan ◽  
Paul M. Coussens ◽  
...  

Follicle development is regulated by the interaction of endocrine and intrafollicular factors, as well as by numerous intracellular pathways, which involves the transcription of new genes, although not all are known. The aim of the present study was to determine the expression of a set of unknown genes identified by bovine cDNA microarray analysis in theca and granulosa cells of dominant and subordinate follicles, collected at a single stage of the first follicular wave using quantitative real-time polymerase chain reaction. Differences were further examined at three stages of the follicular wave (emergence, selection and dominance) and bioinformatics tools were used to identify these originally unknown sequences. The suggested name function and proposed role for the novel genes identified are as follows: MRPL41 and VDAC2, involved in apoptosis (dominant follicle development); TBC1D1 stimulates cell differentiation (growth associated with dominant follicle selection and development); STX7, promotes phagocytosis of cells (subordinate follicle regression); and SPC22 and EHD3, intracellular signalling (subordinate follicle regression). In conclusion, we have identified six novel genes that have not been described previously in ovarian follicles that are dynamically regulated during dominant follicle development and presumably help mediate intracellular signalling, cell differentiation, apoptosis and phagocytosis, events critical to follicular development.


Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 219
Author(s):  
Subir Sarker ◽  
Christabel Hannon ◽  
Ajani Athukorala ◽  
Helle Bielefeldt-Ohmann

Emerging viral disease is a significant concern, with potential consequences for human, animal and environmental health. Over the past several decades, multiple novel viruses have been found in wildlife species, including reptiles, and often pose a major threat to vulnerable species. However, whilst a large number of viruses have been described in turtles, information on poxvirus in cheloniids remains scarce, with no molecular sequence data available to date. This study characterizes, for the first time, a novel poxvirus, here tentatively designated cheloniid poxvirus 1 (ChePV-1). The affected cutaneous tissue, recovered from a green sea turtle (Chelonia mydas) captured off the Central Queensland coast of Australia, underwent histological examination, transmission electron microscopy (TEM), DNA extraction and genomic sequencing. The novel ChePV-1 was shown to be significantly divergent from other known poxviruses and showed the highest sequence similarity (89.3%) to avipoxviruses (shearwater poxvirus 2 (SWPV2)). This suggests the novel ChePV-1 may have originated from a common ancestor that diverged from an avipoxvirus-like progenitor. The genome contained three predicted unique genes and a further 15 genes being truncated/fragmented compared to SWPV2. This is the first comprehensive study that demonstrates evidence of poxvirus infection in a marine turtle species, as well as a rare example of an avipoxvirus crossing the avian-host barrier. This finding warrants further investigations into poxvirus infections between species in close physical proximity, as well as in vitro and in vivo studies of pathogenesis and disease.


2019 ◽  
Vol 18 (4) ◽  
pp. 109-117 ◽  
Author(s):  
M. A. Zaytseva ◽  
L. A. Yasko ◽  
L. I. Papusha ◽  
A. E. Druy

Gliomas are the most common central nervous system tumors demonstrating an extremely broad range of clinical behavior. Over last few decades the understanding of molecular genetic mechanisms of tumor initiation and progression increased significantly. Furthermore, the identification of prognostic and predictive biomarkers aids the development of personalized and risk-adapted therapeutic approaches. In this review, we summarize the molecular findings in pediatric gliomas, both low and high grade (LGG and HGG), focusing on recurrent somatic mutations. There are nucleotide substitutions in BRAF, H3F3A, Hist1H3B/С, IDH1/2 genes, BRAF and NTRK1/2/3 fusions, and CDKN2A/B copy-number aberrations, known to be clinically relevant in the prognosis defining or predicting the efficacy of targeted therapy. We also describe how these findings could pave the way towards the novel genetic classification and risk-group stratification for pediatric patients with glial tumors.


2006 ◽  
Vol 56 (3) ◽  
pp. 583-586 ◽  
Author(s):  
Elena P. Ivanova ◽  
John P. Bowman ◽  
Richard Christen ◽  
Natalia V. Zhukova ◽  
Anatoly M. Lysenko ◽  
...  

A yellow-pigmented, non-motile, Gram-negative bacterium, designated Fg 69T, was isolated from a sediment sample collected in Chazhma Bay (Sea of Japan). The novel organism grew at 10–35 °C, was neutrophilic and required 3–10 % NaCl for optimal growth. Strain Fg 69T was able to degrade starch and to hydrolyse gelatin and Tween 80 weakly but not casein or agar. Predominant cellular fatty acids comprised n-C15 and n-C16 branched-chain and straight-chain saturated and unsaturated fatty acids, including iso-C15 : 0 (5 %), anteiso-C15 : 0 (11 %), C15 : 0 (9 %), iso-C15 : 1 (5 %), iso-C16 : 0 (8 %), C16 : 0 (5 %) and C16 : 1 ω7 (5 %) and iso- and anteiso-branched 2-OH and 3-OH C15 : 0 to C17 : 0 fatty acids (26 % in total). The G+C content of the DNA was 40·4 mol%. 16S rRNA gene sequence data indicated that strain Fg 69T belonged to the genus Salegentibacter but was distinct from recognized Salegentibacter species (94–95 % sequence similarity). Based on these results, a novel species, Salegentibacter flavus sp. nov., is proposed. The type strain is Fg 69T (=KMM 6000T=CIP 107843T).


2013 ◽  
Vol 63 (Pt_4) ◽  
pp. 1417-1420 ◽  
Author(s):  
Masanori Tohno ◽  
Maki Kitahara ◽  
Hidehiko Inoue ◽  
Ryuichi Uegaki ◽  
Tomohiro Irisawa ◽  
...  

A taxonomic study was conducted on two Gram-reaction-positive, catalase-negative, irregular short-rod-shaped or coccoid lactic acid bacteria, designated strains SG25T and SG23, that were isolated from grains of fermented Japanese rice (Oryza sativa L. subsp. japonica). A phylogenetic analysis based on 16S rRNA gene sequence data clearly showed that the strains belonged to the genus Weissella and were most closely related to Weissella soli LMG 20113T (with a sequence similarity of 96.9 % for each novel strain). The peptidoglycan of each strain contained the amino acids glutamic acid, lysine, serine and alanine in a molar ratio of 1.0 : 1.2 : 0.5 : 3.0, respectively. On the basis of the unusual phenotypic characteristics of the novel strains and the low levels of DNA–DNA relatedness recorded between each novel strain and Weissella soli JCM 12536T, strains SG25T and SG23 represent a single novel species in the genus Weissella , for which the name Weissella oryzae sp. nov. is proposed. The type strain is SG25T ( = JCM 18191T  = DSM 25784T).


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dimitri Boeckaerts ◽  
Michiel Stock ◽  
Bjorn Criel ◽  
Hans Gerstmans ◽  
Bernard De Baets ◽  
...  

AbstractNowadays, bacteriophages are increasingly considered as an alternative treatment for a variety of bacterial infections in cases where classical antibiotics have become ineffective. However, characterizing the host specificity of phages remains a labor- and time-intensive process. In order to alleviate this burden, we have developed a new machine-learning-based pipeline to predict bacteriophage hosts based on annotated receptor-binding protein (RBP) sequence data. We focus on predicting bacterial hosts from the ESKAPE group, Escherichia coli, Salmonella enterica and Clostridium difficile. We compare the performance of our predictive model with that of the widely used Basic Local Alignment Search Tool (BLAST). Our best-performing predictive model reaches Precision-Recall Area Under the Curve (PR-AUC) scores between 73.6 and 93.8% for different levels of sequence similarity in the collected data. Our model reaches a performance comparable to that of BLASTp when sequence similarity in the data is high and starts outperforming BLASTp when sequence similarity drops below 75%. Therefore, our machine learning methods can be especially useful in settings in which sequence similarity to other known sequences is low. Predicting the hosts of novel metagenomic RBP sequences could extend our toolbox to tune the host spectrum of phages or phage tail-like bacteriocins by swapping RBPs.


2010 ◽  
Vol 60 (3) ◽  
pp. 603-609 ◽  
Author(s):  
Lyudmila A. Romanenko ◽  
Naoto Tanaka ◽  
Galina M. Frolova

Two bacterial strains, KMM 3891T and KMM 3892, were isolated from internal tissues of the marine mollusc Umbonium costatum collected from the Sea of Japan. The novel isolates were Gram-negative, aerobic, faint pink–reddish-pigmented, rod-shaped, non-motile, stenohaline and psychrotolerant bacteria that were unable to degrade most tested complex polysaccharides. Polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Fatty acid analysis revealed C17 : 1 ω6c, C17 : 0, C16 : 0 and C16 : 1 ω7c as the dominant components. The major isoprenoid quinone was Q-7. The DNA G+C content of strain KMM 3891T was 51.7 mol%. According to phylogenetic analysis of 16S rRNA gene sequences, strains KMM 3891T and KMM 3892 were positioned within the Gammaproteobacteria as a separate branch, sharing <93 % sequence similarity to their phylogenetic relatives including Saccharophagus degradans, Microbulbifer species, Endozoicomonas elysicola, Simiduia agarivorans and Teredinibacter turnerae. Based on phenotypic characterization and phylogenetic distance, the novel marine isolates KMM 3891T and KMM 3892 represent a new genus and species, for which the name Umboniibacter marinipuniceus gen. nov., sp. nov. is proposed. The type strain of Umboniibacter marinipuniceus is KMM 3891T (=NRIC 0753T =JCM 15738T).


2011 ◽  
Vol 61 (7) ◽  
pp. 1515-1520 ◽  
Author(s):  
Jaewoo Yoon ◽  
Satoru Matsuda ◽  
Kyoko Adachi ◽  
Hiroaki Kasai ◽  
Akira Yokota

A Gram-negative-staining, obligately aerobic, non-motile, rod-shaped and chemoheterotrophic bacterium, designated strain MN1-1006T, was isolated from an ascidian (sea squirt) sample, and was studied using a polyphasic taxonomic approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the new isolate shared approximately 93–99% sequence similarity with recognized species of the genus Rubritalea within the phylum ‘Verrucomicrobia’. DNA–DNA hybridization values between strain MN1-1006T and Rubritalea squalenifaciens HOact23T and Rubritalea sabuli YM29-052T were 57% and 14.5%, respectively. Strain MN1-1006T produced carotenoid compounds that rendered the cell biomass a reddish pink colour. The strain also contained squalene. The cell-wall peptidoglycan of the novel strain contained muramic acid and meso-diaminopimelic acid. The DNA G+C content of strain MN1-1006T was 51.4 mol%. The major cellular fatty acids were iso-C14:0, iso-C16:0 and anteiso-C15:0. The major isoprenoid quinone was MK-9. On the basis of these data, it was concluded that strain MN1-1006T represents a novel species of the genus Rubritalea, for which the name Rubritalea halochordaticola sp. nov. is proposed. The type strain is MN1-1006T ( = KCTC 23186T = NBRC 107102T).


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