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12 recordsLinked to original sources
PubMed2026

Comparative transcriptome analysis provides insights into dorso-ventral color pattern formation of Holothuria edulis.

Animal body color patterns are highly diverse and play critical roles in camouflage, intraspecific communication, and environmental adaptation. Holothuria edulis, an important echinoderm inhabiting tropical waters, exhibits a typical dorsoventral dichromatism. This unique body color difference represents a key phenotypic trait for its habitat adaptation; however, the core differential genes regulating this trait remain to be elucidated. In this study, comparative transcriptome sequencing was performed on the dorsal and ventral body wall tissues of H. edulis, leading to the identification of a number of differentially expressed genes (DEGs), followed by GO functional annotation and KEGG pathway enrichment analysis. GO enrichment analysis indicated that the DEGs were significantly enriched in functional categories such as extracellular region, peptidase inhibitor activity, and tetrapyrrole binding. KEGG pathway analysis further revealed significant enrichment of protein digestion and absorption, the TNF signaling pathway, and cholesterol metabolism. Notably, the pigmentation-related gene FMO2 was highly expressed in the dorsal body wall tissue, whereas cyp1a1, ZIC1, Slc7a11, WNT-1, and ADAMTS20 were highly expressed in the ventral body wall tissue. This study identified DEGs and enriched pathways associated with dorsoventral body color differences in H. edulis, providing new insights into the molecular regulatory mechanisms underlying body color pattern formation. From the perspective of aquaculture applications, body color is one of the important traits affecting the quality and market value of sea cucumber products. Elucidating the molecular mechanisms of body color variation can provide a scientific basis for molecular marker-assisted breeding of superior sea cucumber variety.

Animals↗
PubMed2024

Proteome analysis provides insights into sex differences in Holothuria Scabra.

Sex-determining mechanism is still ambiguous for sea cucumber Holothuria scabra which only manifests gonochorism in gonad. In this study, proteomic analysis was employed to delineate sex-related proteins and genes in gonads of H. scabra, subsequently validated through Quantitative real-time polymerase chain reaction (qRT-PCR). A total of 5,313 proteins were identified via proteome sequencing. Among these, 817 proteins exhibited expression in both the ovary and testis, with 445 proteins displaying up-regulation and 372 proteins showing down-regulation (ovary vs testis). Furthermore, 136 and 69 proteins were identified as ovary-specific and testis-specific Differentially Abundant Proteins (DAPs), respectively. And 9 DAP coding genes which play crucial role in ovary and testis were verified by qRT-PCR. Notably, 24 ovary-bias proteins enriched in ribosome pathway strongly indicated the crucial role of ribosome in ovary. This study serves to furnish novel evidence pertaining to sex differences in H. scabra.

Animals↗
PubMed1979

Nucleosome organization during germ cell development in the sea cucumber Holothuria tubulosa.

Conformational changes that occur in chromatin from developing germ cells of the echinoderm Holothuria tubulosa have been probed with micrococcal nuclease. The results indicate that the extent of DNA degradation to acid-soluble nucleotides is highest in chromatin at the early stages of gonad growth, being drastically subdued in the mature sperm cell. Production of nucleosomal particles also varies with development, involving at least 70% of the chromatin at the final stage of maturation, whereas in immature germ cells it remains much lower. In contrast, electrophoretic analysis for DNA size has shown that the average nucleosome repeat length, about 227 base pairs, does not change throughout the maturation process. However, kinetics of the enzyme reaction have revealed that, although brief digestion of chromatin from both immature gonads and sperm yields comparable series of higher oligomers, extensive digest patterns differ widely. Sperm chromatin, highly protected, releases a 275 base pair intermediate fragment, wholly absent in immature gonads. The 145 base pair core released in both chromatins is not further digested in sperm. In comparison to sperm chromatin, that of immature germ cells is much more susceptible to fragmentation, yielding the usual set of smaller subnucleosomal fragments. These data suggest the induction of differential accessibilities of chromatin DNA with maturation, which is not accompanied by displacement of the histone complement. The histone variants present in this species may well be instrumental in the process.

Animals↗
PubMed1975

Evolutionary variation between a monomer and a dimer arginine kinase. Purification of the enzyme from Holothuria forskali and a comparison of some properties with that from Homarus vulgaris.

1. A purification procedure for the dimeric arginine kinase of the sea cucumber Holothuria forskali is described. 2. The enzyme has a mean molecular weight of 77250 and is composed of two equal, dissociable subunits. 3. It also shows co-operativity between substrate binding at one catalytic site to a much greater extent than the nomomeric lobster arginine kinase for which such co-operativity could not be detected unambiguously. The constants for substrate binding are reported assuming that the enzyme follows rapid-equilibrium random kinetics. From a comparison with other species, the development of co-operativity between the nucleotide- and guanidine-binding sites on one subunit is suggested to have occurred more than once in the evolution of the phosphagen kinases and is not dependent on subunit aggregation. 4. Both enzymes show similar pH profiles for thermal inactivation at 22 degrees C and have very similar stabilities. Above 40 degrees C the dimeric enzyme is much more stable than the monomer. Rate constants for heat inactivation and Arrhenius activation energies are reported. 5. The dimeric enzyme is also more stable to urea inactivation. Substrates and argininic acid all improve the stability of both enzymes. The effects of individual substrates are more distincitive with the dimeric enzymes and increase its stability to an extent that makes it about as stable as dogfish creatine kinase. In the physiological range dimerization does not seem to confer any particular advantage with respect to stability over the monomer form.

Animals↗
PubMed1975

Effects of anions on a monomeric and a dimeric arginine kinase.

1. Some effects of anions on the rates of phosphoarginine synthesis by monomeric (lobster) and by dimeric (Holothuria forskali) arginine kinases are reported. 2. As with creatine kinase, acetate ions activate both enzymes: Cl- was also found to activate both although this was an inhibitor of creatine kinase. 3. NO3- inhibits the lobster enzyme. Inhibition is of the mixed type with respect to MgATP. Ki greater than Ki' and Ks greater than Ks' indicating that the presence of NO3- promotes the binding of substrate and vice versa. 4. NO3- alone has no effect on the difference spectrum of the lobster enzyme but in the presence of arginine, MgATP, MgADP, MgAMP or MgIDP the difference spectrum is greatly enhanced. A profound effect on the ionization state of tyrosine residues is inferred. 5. With the Holothuria enzyme low concentrations of NO3- activate in a manner that is competitive with arginine. Higher concentrations cause inhibition of the mixed type with respect to arginine in a similar manner to that found with MgATP for the lobster kinase. 6. Of a range of anions tested only NO3- and NO2- enhanced the inhibition of enzyme activity by MgADP, indicating the formation of a pseudo-transition-state dead-end complex, enzyme-arginine-NO3--MgADP. The effect was essentially independent of temperature with the Holothuria enzyme, but with the lobster enzyme was much less marked and temperature dependent. The difference may reflect the different stabilities of the monomer and dimer enzymes, although with neither arginine kinase is the stabilization of the dead-end complex as marked as is found with creatinine kinase.

Adenosine Diphosphate↗
PubMed1976

Effects of arginine and some analogues of the partial adenosine triphosphate-adenosine diphosphate exchange reaction catalysed by arginine kinase. Evolutionary divergence in the mechanism of action of a monomer and a dimer arginine kinase.

1. Both the monomer arginine kinase from lobster muscle and the dimer arginine kinase from Holothuria forskali catalyse the ATP-ADP partial exchange reaction at rates equal to 3 and 0.6% of the normal rate of transphosphorylation respectively. The Mg2+-nucleotide complex is the substrate for this as it is for the kinase reaction. 2. Analogues of arginine inhibit the exchange reaction of the lobster enzyme but enhance that of the Holothuria enzyme. 3. With the lobster enzyme NO3- has no effect on the exchange reaction alone and inhibit only slightly the apparent enhancement of the exchange reaction produced by the addition of arginine. This is compatible with previous findings for this enzyme that formation of the anion-stabilized dead-end complex, enzyme-arginine-MgADP-NO3-, does not occur to any marked degree. 4. About 80% of the ADP-ATP exchange reaction of the lobster enzyme remains after inhibition with iodoacetamide. This is further decreased to 65% by the addition of L-arginine, indicating that this substrate does bind to the thiolmodified enzyme. 5. It is concluded that the partial exchange reaction is a genuine phenomenon not mediated by trace amounts of arginine. From the effects of arginine and related compounds it would appear that during the normal kinase reaction the partial ATP-ADP exchange reaction is suppressed in the lobster enzyme but enhanced in the Holothuria enzyme. This reflects a remarkable evolutionary divergence of two homologous enzymes.

Adenosine Diphosphate↗
PubMed1978

Comparative levels of muscle glycolytic enzymes in mammals, fish, echinoderm and molluscs.

1. Levels of glycolytic enzymes were determined in terms of units of enzyme/mg protein in rat striated muscle, carp lateral muscle, holothuria longitudinal muscle of the body wall, and a snail foot muscle. 2. An attempt has been made to correlate levels of glycolytic enzymes as a parameter to establish a "biochemical distance" at molecular level and correlate this with the phylogenetic position in animals sufficiently separated in the animal tree of evolution. 3. The possibility of a peculiar kinetic behaviour of the glycolytic pathway in each muscle tissue studied, has been analyzed as the profiles of the ratios of pairs of enzymes bearing a substrate-product dependence. 4. A possible "futile synthesis" of some glycolytic enzymes, such as FDP-aldolase in the case of fish muscle, is proposed.

Animals↗
PubMed1976

Isotonic and isometric responses of different tonic muscles to agonists and antagonists.

1 With isotonic recording the percentage of muscle shortening as compared with the maximal possible shortening, and with isometric recording the percentage of developed tension were determined. In relatively 'thick' muscles, such as dorsal leech muscle, frog rectus abdominis or protractor pharynx of holothuria (0.3-0.8 mm thick), the concentrations of a full agonist (carbachol) producing a given percentage of tension, (e.g. 50%) are about 5 times greater than the concentrations, producing the same percentage of shortening. In 'thin' muscles the difference between the percentage of shortening and tension is either small (retractor dentis of the sea urchin, 0.1 mm thick, response to carbachol) or absent (guinea-pig ileum, 0.06 mm thick, responses to methylfurmethide). The possible mechanism underlying this difference is discussed. 2 With partial agonists (dodecamethonium and heptamethonium) the fractional tension of the frog rectus abdominis is always less than the fractional shortening and the correlation between shortening and tension is the same as in the case of full agonists. 3 The blocking activity of (+)-tubocurarine on the frog rectus abdominis is the same in isotonic and in isometric conditions. 4 On the frog rectus abdominis the alkylating agent, decamethonium mustard, does not produce any 'parallel shift' of the dose-response curve for carbachol, the only result of alkylation being a decrease in maximal response, which is more pronounced in isometric than in isotonic conditions. The degree of decrease is in accordance with the correlation between percentage of shortening and percentage of tension in the absence of alkylating agent. Probably this muscle does not possess any 'spare receptors'. 5 On the frog muscle the dose-isometric response curve for acetylcholine (ACh) is shifted toward greater concentration about 33-fold as compared with the dose-isotonic response curve but after the inhibition of cholinesterases the shift is only about 6-fold. The same shift (5-fold) is observed for carbachol, which is not hydrolysed by cholinesterases. The results with ACh are due to the fact, that after cholinesterase inhibition the sensitivity to ACh increases in isotonic conditions only 13-fold, but in isometric conditions it increases 71-fold. Probably under isometric conditions, when the muscle remains in the extended state, the rate of hydrolysis of ACh is much greater than under isotonic conditions when the muscle is shortened during contraction.

Acetylcholine↗
PubMedDate not supplied

[Comparative findings on the stereoselectivity of cholinoreceptors].

The potency of the optical isomers of the muscarinomimetic agent 2-methyl-4-dimethylaminomethyl-1.3-dioxolane methiodide (F-2268) was compared on cholinoreceptors, (ChR) of different animals. The greatest difference between optical isomers was observed on the muscarinic ChR of guinea pig ileum smooth muscle cis-L(+)isomer being more than hundred times as potent as cis-D(-)isomer. On the ChR of muscarinic type in the holothuria Cucumaria japonica retractor muscle, cis-L(+)isomer was 25 times as efficient as cis-D(-)isomer. On the ChR of sea urchin and sipunculid locomotor muscles, optical isomers differ only 3 to 5 times. There was no difference between the effect of optical isomers on the ChR of muscarinic type which mediate hyperpolarization in the neurones of the gastropod mollusc Planorbarius corneus. This suggest that some changes in ChR stereoselectivity may occur in the course of evolution.

Animals↗