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At least 19 recordsLinked to original sources
PubMed2026

Novelty, diversity, and genetic dark matter in enterococci of invertebrates.

Enterococci appear to have originated in the guts of early terrestrializing arthropods and invertebrates over 425 million years ago-hosts that are now highly diverse and widespread in nature today. Yet most knowledge of the genus comes from human infection-associated lineages with genomes swollen by the recent accretion of foreign DNA conveyed by mobile elements. Because invertebrates dominate terrestrial animal diversity and biomass, they would be predicted to constitute a major but little-explored reservoir of enterococcal diversity. We therefore systematically examined Enterococcus association and species diversification in invertebrate hosts of the comparatively natural, isolated, but well-characterized environment of the Azorean island of Terceira. Over 100 invertebrate specimens were examined for associated enterococci, which were taxonomically classified by whole-genome sequencing. Supporting the existence of a large pool of uncharacterized enterococci and Enterococcus-adapted genes, 40% (eight of 20) of the Enterococcus species identified were either undescribed, including four candidate new species described here, or very recently discovered. In contrast, control isolates from vertebrates were exclusively of known species typical of sampling elsewhere, discounting geographic isolation as a main driver of the novelty observed. Further, because of the abundance of E. casseliflavus and E. flavescens in this collection, we obtained the resolution necessary to quantify the divergence and decipher the drivers of speciation in the controversial division between these naturally vancomycin-resistant species. These findings provide robust support for the existence of a large pool of new species and unexplored adaptive traits in invertebrate-associated enterococci-diverse environmental survival traits optimized for expression in an enterococcal background, and well positioned for transmission into human-associated enterococcal strains.IMPORTANCEEnterococci are auxotrophic gut-associated bacteria that co-evolved with their terrestrial hosts over many eons. In the last 75 years-the "antibiotic era"-E. faecalis and E. faecium gained genes for antibiotic resistance and enhanced virulence, emerging as leading causes of multidrug-resistant infection. Little is known about the source of those genes or the pathway by which they entered human-associated strains. A recent global survey suggested a potentially large repository of uncharacterized genetic diversity in the enterococci of invertebrates. We directly tested this prospect by examining enterococci of invertebrate hosts in a largely natural and pastoral environment. Our findings provide clear evidence that invertebrates naturally harbor vast unexplored enterococcal diversity. Moreover, associations are likely driven by intrinsic host selection factors rather than geographic isolation. This expands our knowledge of Enterococcus biodiversity, including the identification of four novel species, identifying a vast reservoir of enterococcal genes available to species that colonize and infect humans.

Animals↗
PubMed2025

Pseudoalteromonas is a novel symbiont of marine invertebrates that exhibits broad patterns of phylosymbiosis.

Despite growing insights into the composition of marine invertebrate microbiomes, our understanding of their ecological and evolutionary patterns remains poor, owing to limited sampling depth and low-resolution datasets. Previous studies have provided mixed results when evaluating patterns of phylosymbiosis between marine invertebrates and marine bacteria. Here, we investigated potential animal-microbe symbioses in Pseudoalteromonas, an overlooked bacterial genus consistently identified as a core microbiome taxon in diverse invertebrates. Using a pangenomic analysis of 236 free-living and invertebrate-associated bacterial strains (including two new nematode-associated isolates generated in this study), we confirm that Pseudoalteromonas is a novel symbiont with substantial evidence of phylosymbiosis across at least three marine invertebrate phyla (e.g., Nematoda, Mollusca, and Cnidaria). Patterns of symbiosis were consistent irrespective of geography (including in Antarctica), with FISH images from nematodes indicating that bacterial symbionts form biofilms in the mouth and esophagus. The evolutionary history of Pseudoalteromonas is marked by substantial host-switching and lifestyle transitions, and host-associated genomes suggest that these bacteria are facultative symbionts involved in nutritional mutualisms. In marine environments, we hypothesize that horizontally-acquired symbionts may have co-evolved with invertebrates, using host mucus as a physical niche and food source, while providing their animal hosts with Vitamin B, amino acids, and bioavailable carbon compounds in return.

Marine Invertebrates↗
PubMed2026

DNA methylation-based ageing in a deuterostome invertebrate: an epigenetic clock for the crown-of-thorns seastar (Acanthaster cf. solaris).

Accurate and reliable ageing tools are essential for wildlife conservation and management. While DNA methylation has emerged as a promising tool for age estimation in vertebrates, its application to invertebrates remains contested and has been limited to arthropods. Here, we develop an epigenetic clock for the Pacific crown-of-thorns seastar (CoTS; Acanthaster cf. solaris), a destructive coral predator contributing to habitat degradation across Indo-Pacific reefs. Using Oxford Nanopore Technologies, we generated whole-genome DNA methylation profiles across five age groups and identified 1910 CpG sites with methylation patterns significantly associated with age. We then fitted age prediction models using elastic net regression and evaluated predictive performance with leave-one-out cross-validation (LOOCV), achieving a mean absolute error of 0.31 ± 0.22 years, corresponding to 4-6% of the CoTS lifespan (5-8 years). This accuracy suggests the potential to differentiate annual cohorts, supporting future management-relevant inference. To facilitate practical implementation, we constructed an optimized epigenetic clock from 14 CpG sites consistently selected across LOOCV iterations. Our results demonstrate that DNA methylation-based age estimation is feasible in a deuterostome invertebrate, extending epigenetic ageing approaches beyond arthropods and establishing their potential to advance age determination and management in invertebrates that lack reliable ageing methods.

Animals↗
PubMed1976

Activities of citrate synthase and NAD+-linked and NADP+-linked isocitrate dehydrogenase in muscle from vertebrates and invertebrates.

1. The activities of citrate synthase, NAD+-linked and NADP+-linked isocitrate dehydrogenase were measured in muscles from a large number of animals, in order to provide some indication of the importance of the citric acid cycle in these muscles. According to the differences in enzyme activities, the muscles can be divided into three classes. First, in a number of both vertebrate and invertebrate muscles, the activities of all three enzymes are very low. It is suggested that either the muscles use energy at a very low rate or they rely largely on anaerobic glycolysis for higher rates of energy formation. Second, most insect flight muscles contain high activities of citrate synthase and NAD+-linked isocitrate dehydrogenase, but the activities of the NADP+-linked enzyme are very low. The high activities indicate the dependence of insect flight on energy generated via the citric acid cycle. The flight muscles of the beetles investigated contain high activities of both isocitrate dehydrogenases. Third, other muscles of both vertebrates and invertebrates contain high activities of citrate synthase and NADP+-liniked isocitrate dehydrogenase. Many, if not all, of these muscles are capable of sustained periods of mechanical activity (e.g. heart muscle, pectoral muscles of some birds). Consequently, to support this activity fuel must be supplied continually to the muscle via the circulatory system which, in most animals, also transports oxygen so that energy can be generated by complete oxidation of the fuel. It is suggested that the low activities of NAD+-linked isocitrate dehydrogenase in these muscles may be involved in oxidation of isocitrate in the cycle when the muscles are at rest. 2. A comparison of the maximal activities of the enzymes with the maximal flux through the cycle suggests that, in insect flight muscle, NAD+-linked isocitrate dehydrogenase catalyses a non-equilibrium reaction and citrate synthease catalyses a near-equilibrium reaction. In other muscles, the enzyme-activity data suggest that both citrate synthase and the isocitrate dehydrogenase reactions are near-equilibrium.

Animals↗
PubMed1976

The maximum activities of hexokinase, phosphorylase, phosphofructokinase, glycerol phosphate dehydrogenases, lactate dehydrogenase, octopine dehydrogenase, phosphoenolpyruvate carboxykinase, nucleoside diphosphatekinase, glutamate-oxaloacetate transaminase and arginine kinase in relation to carbohydrate utilization in muscles from marine invertebrates.

Comparison of the activities of hexokinase, phosphorylase and phosphofructokinase in muscles from marine invertebrates indicates that they can be divided into three groups. First, the activities of the three enzymes are low in coelenterate muscles, catch muscles of molluscs and muscles of echinoderms; this indicates a low rate of carbohydrate (and energy) utilization by these muscles. Secondly, high activities of phosphorylase and phosphofructokinase relative to those of hexokinase are found in, for example, lobster abdominal and scallop snap muscles; this indicates that these muscles depend largely on anaerobic degradation of glycogen for energy production. Thirdly, high activities of hexokinase are found in the radular muscles of prosobranch molluscs and the fin muscles of squids; this indicates a high capacity for glucose utilization, which is consistent with the high activities of enzymes of the tricarboxylic acid cycle in these muscles [Alp, Newsholme & Zammit (1976) Biochem. J. 154, 689-700]. 2. The activities of lactate dehydrogenase, octopine dehydrogenase, phosphoenolpyruvate carboxykinase, cytosolic and mitochondrial glycerol 3-phosphate dehydrogenase and glutamate-oxaloacetate transaminase were measured in order to provide a qualitative indication of the importance of different processes for oxidation of glycolytically formed NADH. The muscles are divided into four groups: those that have a high activity of lactate dehydrogenase relative to the activities of phosphofructokinase (e.g. crustacean muscles); those that have high activities of octopine dehydrogenase but low activities of lactate dehydrogenase (e.g. scallop snap muscle); those that have moderate activities of both lactate dehydrogenase and octopine dehydrogenase (radular muscles of prosobranchs), and those that have low activities of both lactate dehydrogenase and octopine dehydrogenase, but which possess activities of phosphoenolpyruvate carboxykinase (oyster adductor muscles). It is suggested that, under anaerobic conditions, muscles of marine invertebrates form lactate and/or octopine or succinate (or similar end product) according to the activities of the enzymes present in the muscles (see above). The muscles investigated possess low activities of cytosolic glycerol 3-phosphate dehydrogenase, which indicates that glycerol phosphate formation is quantitatively unimportant under anaerobic conditions, and low activities of mitochondrial glycerol phosphate dehydrogenase, which indicates that the glycerol phosphate cycle is unimportant in the re-oxidation of glycolytically produced NADH in these muscles under aerobic conditions. Conversely, high activities of glutamate-oxaloacetate transaminase are present in some muscles, which indicates that the malate-aspartate cycle may be important in oxidation of glycolytically produced NADH under aerobic conditions. 3. High activities of nucleoside diphosphate kinase were found in muscles that function for prolonged periods under anaerobic conditions (e.g...

Adenosine Triphosphate↗
PubMed2025

The ecology, evolution, and physiology of Cardinium: a widespread heritable endosymbiont of invertebrates.

Candidatus Cardinium hertigii (Cardinium) are maternally transmitted obligate intracellular bacteria found in a wide range of invertebrate hosts, including arthropods and nematodes. Infection with Cardinium has substantial consequences for host biology, with many strains manipulating host reproduction to favor symbiont transmission by (i) feminizing male hosts, (ii) altering host sex allocation, (iii) inducing parthenogenesis, or (iv) causing cytoplasmic incompatibility. Other Cardinium strains can confer benefits to their host or alter host behavior. Cardinium-modified host phenotypes can result in selective sweeps of cytological elements through host populations and potentially reinforce host speciation. Cardinium has potential for applications in controlling arthropod pest species and arthropod-vectored disease transmission, although much remains to be explored regarding Cardinium physiology and host interactions. In this review, we provide an overview of Cardinium evolution and host distribution. We describe the various host phenotypes associated with Cardinium and how biological and environmental factors influence these symbioses. We also provide an overview of Cardinium metabolism, physiology, and potential mechanisms for interactions with hosts based on recent studies using genomics and transcriptomics. Finally, we discuss new methodologies and directions for Cardinium research, including improving our understanding of Cardinium physiology, response to environmental stress, and potential for controlling arthropod pest populations.

Symbiosis↗
PubMed1977

Evidence for new catecholamines or related amino acids in some invertebrate sensory neurons.

In certain sensory neurons of many different invertebrate species, including the sea anemones. Metridium senile and Tealia felina and the crustacean Artemia salina, fluorophores are formed during the course of the fluorescent histochemical technique of Falck-Hillarp. The presumed catecholamine nature of the neuronal fluorogenic compound was investigated by microspectrofluorometry, and the spectral characteristics of the fluorescence in the taxonomically different species was found to be very similar (excitation maximum at 375 nm with a smaller peak or shoulder at 330 nm and sometimes a shoulder in the spectrum at 410 nm; emission maximum at 475 nm). The emission maximum coincides with that of the catecholamines and DOPA (475 nm). The excitation maximum (375 nm) directly after formaldehyde treatment, however- differs from that of the catecholamines and DOPA (410 nm), but is similar to the excitation maximum displayed by these catechol derivatives at acid pH. The spectral characteristics of the fluorophore in the sensory cells might therefore theoretically be explained by an acid pH in the cells. This means improbable, however, and it is suggested that the phenomenon is due to the presence of unknown catechol derivatives. Analyses of the pH-dependent spectral changes indicate that the presumed catechol derivative in Tealia felina is beta-hydroxylated, whereas that in Artemia salina is not.

Amino Acids↗
PubMed2024

Vertebrate and invertebrate animal infection models of Candida auris pathogenicity.

Candida auris is an emerging fungal pathogen with several concerning qualities. First recognized in 2009, it has arisen in multiple geographically distinct genomic clades nearly simultaneously. C. auris strains are typically multidrug resistant and colonize the skin much better than most other pathogenic fungi; it also persists on abiotic surfaces, enabling outbreaks due to transmission in health care facilities. All these suggest a biology substantially different from the 'model' fungal pathogen, Candida albicans and support intensive investigation of C. auris biology directly. To uncover novel virulence mechanisms in this species requires the development of appropriate animal infection models. Various studies using mice, the definitive model, are inconsistent due to differences in mouse and fungal strains, immunosuppressive regimes, doses, and outcome metrics. At the same time, developing models of skin colonization present a route to new insights into an aspect of fungal pathogenesis that has not been well studied in other species. We also discuss the growing use of nonmammalian model systems, including both vertebrates and invertebrates, such as zebrafish, C. elegans, Drosophila, and Galleria mellonella, that have been productively employed in virulence studies with other fungal species. This review will discuss progress in developing appropriate animal models, outline current challenges, and highlight opportunities in demystifying this curious species.

Animals↗
PubMed2026

Di-, tri-, and tetranucleotide frequencies covary with lifespan and genome size across protostome invertebrates.

Animal lifespans span orders of magnitude, yet how genome sequence covaries with lifespan remains poorly characterized outside vertebrates. Although promoter CpG density has been linked to vertebrate longevity due to its gene-regulatory function through DNA methylation, it is unclear whether such patterns are promoter- and CpG-specific, or if they reflect broader sequence evolution. We curated maximum lifespan estimates for 466 protostome species spanning eight phyla with available genome assemblies and quantified mono-, di-, tri-, and tetranucleotide composition across whole genomes, intergenic regions, and six gene-associated regions (two upstream regions, exons, introns, and two downstream regions) defined using Benchmarking Universal Single-Copy Orthologs. Dinucleotide observed/expected ratios showed significant associations with lifespan and genome size in different ways. Lifespan-associated motifs were most pronounced in gene-associated non-coding regions, especially in introns and downstream regions, whereas genome-size effects were strongest in whole-genome and intergenic sequence. Tri- and tetranucleotide observed/expected ratios broadly recapitulated this regional organization. In contrast, GC content was not associated with lifespan across regions, indicating that the observed signals are not explained by mononucleotide composition but instead by how those nucleotides are arranged into short sequence motifs. These results suggest that lifespan and genome size show distinct but overlapping associations with regional sequence composition across invertebrate species and that lifespan-associated motif evolution extends beyond vertebrate promoter methylation architectures.

CpG density↗
PubMed1976

The activator of human cerebroside sulphatase. Activating effect on the acidic forms of the sulphatases from invertebrates.

1) Acidic forms of the sulphatase were partially purified from the following invertebrate species: Tethya aurantium (Porifera), Patella vulgata (mollusca), Maja squinado (Arthropoda), Marthasterias glacialis (Echinodermata) and Microcosmus sulcatus (Tunicata). Enzyme preparations thus obtained cleaved cerebroside sulphates (sulphatides) only in the presence of either specific detergents (e.g. taurodeoxycholate) or an activator protein isolated from human liver. This corresponds to the findings on purified sulphatase A of human origin. 2) At low concentrations, the activating effect was proportional to the amount of activator protein applied; at higher concentrations, proportionality was obtained only in some cases. On a molar basis, less of the activator protein was required to achieve the same activation as taurodeoxycholate. At optimum concentrations of the detergent however, the activation was much higher. 3) The enzyme specificity of the activator and some evolutionary implications are discussed.

Acetylglucosaminidase↗
PubMed1977

Adenosine triphosphate-activated adenylate deaminase from marine invertebrate animals. Properties of the enzyme from lugworm (Arenicola cristata) body-wall muscle.

Adenylate deaminase (AMP aminohydrolase, EC 3.5.4.6) from lugworm (Arenicola cristata) body-wall muscle was partially purified by extraction in KCl solutions and chromatography on phosphocellulose. Enzyme activity was eluted from the column at two salt concentrations. Both forms show co-operative binding of AMP (Hill coefficient, h, 2.85) with s0.5 values of 20 mM and 15.6 mM. ATP and ADP act as positive effectors lowering h to 1.07 and s0.5 to 2mM. The apparent Ka (activation) for ATP was 1.5mM. GTP is an inhibitor with an apparent Ki of 0.12 mM. In vivo the ATP-activated adenylate deaminase is in the active form and may be regulated by changes in GTP concentrations. Adenylate deaminase may act as a primary ammonia-forming enzyme in ammonotelic marine invertebrates with the purine nucleotide cycle.

AMP Deaminase↗
PubMed1976

Enzyme activities associated with an invertebrate iridovirus: nucleotide phosphohydrolase activity associated with iridescent virus type 6 (CIV).

A nucleoside triphosphate phosphohydrolase activity is firmly associated with a purified invertebrate iridovirus, iridescent virus type 6. The enzyme activity hydrolyzes all the nucleoside triphosphates, but has a high preference for ATP. The products of the reaction are nucleoside diphosphates. Conditions for nucleoside triphosphate phosphohydrolase activity are described.

Adenosine Diphosphate↗
PubMed1977

Distribution of sulfated mucopolysaccharides in invertebrates.

The sulfated mucopolysaccharide composition of 22 species of invertebrates belonging to the phyla Arthropoda, Mollusca, Annelida, Tunicata, Echinodermata, Coelenterata, and Porifera was analyzed. It is shown that all the species contain variable amounts of one or more types of sulfated mocopolysaccharides, most of which similar to the ones found in vertebrates. It is shown also that each species has a characteristic composition, differing from each other regarding the relative amount and type of chondroitin sulfates A, B, and C, heparitin sulfate, and heparin. The possible biological role of the sulfated mucopolysaccharides in cell recognition or aggregation or both is discussed in view of the present findings.

Animals↗
PubMed1977

Lead levels in small mammals and selected invertebrates associated with highways of different traffic densities.

Lead levels in small mammals were studied in 6 areas -- 3 associated with highways of different traffic densities, and 3 control sites in forested areas. Lead levels were also studied in insects from 2 traffic areas and in earthworms from different distances from 2 traffic areas. Lead levels were low in insects ranging from 3.84 microng/g to 3.35 microng/g. Lead levels in earthworms were highest in those recovered closest to highways and from the area with the higher traffic volume. Lead levels in mammals generally was highest in mammals from areas of higher traffic densities. Higher levels of lead were found in shrews than in Peromyscus and Microtus.

Animals↗