Grammistes Research Articles

Diversity of intertidal fishes in Porok Beach, Gunungkidul, Yogyakarta

Porok Beach is one of the beaches in Gunung Kidul which has high diversity of fish species, especially in the intertidal zone. The diversity of fish species in Porok Beach needs to be maintained for its sustainability. This research aims to determine the diversity of fish in the intertidal zone of Porok Beach, Gunungkidul, Yogyakarta. The research was conducted on 17th October 2020 and 29th August 2021 with a purposive random sampling method by using a hand net. The results show that there are 5 families and 10 species of fish that were discovered, which consists of 5 species from family Pomacentridae: Pomacentrus brachialis, Stegastes obreptus, Plectroglyphidodon leucozonus, Abudefduf sordidus, and Abudefduf vaigiensis; 2 species from family Gobiidae: 1 individu of Acentrogobius caninus and 2 individu of Istigobius ornatus; 1 species from family Blenniidae: Blenniella gibbifrons; 1 species from family Clinidae: Springeratus xanthosoma; and 1 species from family Serranidae: Grammistes sexlineatus. This indicates that the condition of the intertidal zone in Porok Beach supports many fish species to live well.

Trophic structure of pelagic fishery organism assemblage in the central and western South China Sea in spring revealed by carbon and nitrogen stable isotope analysis

Carbon and nitrogen stable isotope analysis was carried out on pelagic fishery organisms caught in light traps and falling nets in the central and western South China Sea in the spring of 2018. The stable isotope values of the sampled individuals were used to elucidate the isotopic variations for the pelagic fishery organisms, to classify species into trophic functional groups, and to compare the differences of trophic structure among the classified trophic functional groups. The results showed that among 23 fishery species the mean δ13C value of Coryphaena hippurus was the lowest (-17.58‰±0.21‰), and that of Grammistes sexlineatus was the highest (-19.86‰±0.33‰). The mean δ15N values ranged from 8.31‰ in Psenes cyanophrys to (12.46±0.74)‰ in Chirocentrus dorab. The continuous trophic spectrum indicated that the trophic level (TL) for the sampled pela-gic fishery organisms ranged from 3.01 to 4.23, of which 19 species (83% of the total) fell between TL 3.0 and 4.0. The 23 species of fishery organisms were classified into three trophic functional groups, i.e., plankton feeding functional group (PFFG), nekton feeding functional group (NFFG), and mixed feeding functional group (MFFG). The analysis of standard ellipse area (SEA) showed that the PFFG occupied the largest trophic niche width (SEA=1.56‰2), followed by the MFFG (SEA=0.99‰2) and NFFG (SEA=0.31‰2). The MFFG overlapped with PFFG and NFFG in the trophic niche, with a relative percentage of 17% and 26%, respectively. There was no overlap between PFFG and NFFG.

The complete mitochondrial genome of Diploprion bifasciatum (Perciformes, Serranidae)

The complete mitochondrial genome (mitogenome) of Diploprion bifasciatum was first determined. The mitogenome was 16,805 bp in length and contained 13 protein-coding genes, 24 tRNAs, 2 rRNA, and 2 non-coding regions. The overall base composition of the mitogenome was estimated to be T 25.72%, G 17.10%, A 28.24%, and C 28.94%, with a slight A + T bias of 53.96%, indicating an obvious anti-G bias commonly observed invertebrates. It shared 78.9%, 78.7%, 76.8%, and 72.5% identities with that of Grammistes sexlineatus, Epinephelus moara, Plectropomus areolatus, and Hypoplectrus gemma, respectively.

The complete mitochondrial genome of Grammistes sexlineatus (Perciformes, Serranidae)

The complete mitochondrial genome of Grammistes sexlineatus was first determined and studied in the present study. The mitochondrial genome was 16,502 nucleotides that contained 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes and one putative control region. The overall base composition of G. sexlineatus was T 23.74%, C 31.05%, A 28.79%, and G 16.42%, with a slight A + T bias of 52.53%. The gene order and composition of G. sexlineatus mitogenome was similar to the most vertebrate. Meanwhile, a termination-associated sequence (TAS) and the conserved sequence blocks (CSB-2 and CSB-3) were determined in G. sexlineatus control region. The mitochondrial genome would play key role in phylogenetics analysis of the Serranidae.

Further isolation and characterization of grammistins from the skin secretion of the soapfish Grammistes sexlineatus

Soapfishes contain peptide toxins (grammistins) in the skin secretion. Two grammistins (Gs 1 and Gs 2) and six grammistins (Pp 1, Pp 2a, Pp 2b, Pp 3, Pp 4a and Pp 4b) have already been isolated from Grammistes sexlineatus and Pogonoperca punctata, respectively. In this study, five grammistins (Gs A–E), together with grammistins Gs 1 and Gs 2, were further isolated from G. sexlineatus by gel filtration and reverse-phase HPLC. Sequence analyses revealed that grammistins Gs A (28 residues) and Gs C (26 residues) are analogous to grammistin Pp 3 and grammistin Gs B (12 residues) to grammistin Pp 1, while grammistins Gs D (13 residues) and Gs E (13 residues) are identical with grammistins Pp 1 and Pp 2b, respectively. Grammistins Gs A–C exhibited antibacterial activity with a broad spectrum against nine species of bacteria in common with the other grammistins but had no hemolytic activity differing from the other grammistins. Grammistins Gs A–E, Gs 1 and Gs 2 could release carboxyfluorescein entrapped within liposomes made of either phosphatidylcholine or phosphatidylglycerol/phosphatidylcholine (3:1), demonstrating their membrane-lytic activity. However, no clear relationship between the membrane-lytic activity and the biological activity of grammistins was recognized.

Interaction of grammistins with lipids and their antibacterial activity

: Grammistins are hemolytic and ichthyotoxic peptides in the skin secretion of soapfishes and are structurally characterized by their abundance in amphiphilic α-helicity. In the present study, their interaction with lipids and lipid vesicles as well as antibacterial activity were examined using four grammistins (Gs 1 and Gs 2 from Grammistes sexlineatus and Pp 1 and Pp 3 from Pogonoperca punctata). The hemolytic activity of grammistins was inhibited by phospholipids but not by cholesterol. Moreover, grammistins released carboxyfluorescein entrapped within liposomes made of phosphatidylcholine. In contrast, grammistins were found to have antibacterial activity with a broad spectrum against nine species of bacteria, including both Gram-negative and Gram-positive groups. The potency of their antibacterial activity was not related to that of hemolytic activity, suggesting that grammistins bind to membrane phospholipids but lyse erythrocyte and bacterial membranes via different mechanisms. Conclusively, grammistins are new members of the family of cell non-selective membrane-lytic peptides with amphiphilic α-helices, being similar to pardaxins, which are secreted from the skin of soles, and to melittin, which is derived from bee venom.

Primary and secondary structures of grammistins, peptide toxins isolated from the skin secretion of the soapfish Pogonoperca punctata

SUMMARY: Six peptides (grammistins Pp 1, 2a, 2b, 3, 4a and 4b) with both hemolytic and ichthyotoxic activities were isolated from the skin secretion of the soapfish Pogonoperca punctata by gel filtration and reverse-phase high performance liquid chromatography. They were completely sequenced and found to be simple peptides differing from the previous suggestion that they are peculiar peptides with tertiary amine or quaternary ammonium base moieties. Grammistins Pp 1, 2a and 2b were composed of 13 residues, Pp 3 of 25 residues and Pp 4a and 4b of 24 residues. While grammistins Pp 4a and 4b were identical and highly homologous with grammistin Gs 2 previously isolated from another soapfish Grammistes sexlineatus, the other grammistins did not have homologies with any proteinic or peptidic toxins known to date. Judging from circular dichroism data, helical wheel projections and hydrophobic moment plots, all the isolated grammistins are surface-seeking peptides with an abundance in amphiphilic α-helicity, similar to pardaxins from the skin secretion of two species of soles and melittin from bee venom as well as the G. sexlineatus grammistins.

Isolation and structures of grammistins, peptide toxins from the skin secretion of the soapfish Grammistes sexlineatus

Two peptide toxins (named grammistins Gs 1 and Gs 2) with hemolytic and ichthyotoxic activities were isolated from the skin secretion of the soapfish Grammistes sexlineatus. Grammistin Gs 2 showed 6–11× higher hemolytic activity and 10× higher ichthyotoxicity than grammistin Gs 1. The complete amino acid sequences of Gs 1 comprising 25 residues and Gs 2 comprising 24 residues were determined. Although a search by the database failed to find any homologous toxins from other sources, the grammistins were similar in secondary structures as well as biological activities to the two classes of peptide toxins, melittin from the bee venom and pardaxins from the skin secretion of two species of soles. CD experiments and helical wheel projections showed that the grammistins were randomly coiled in distilled water but formed amphiphilic α-helices in the presence of SDS micelles. In addition, they were found to be surface seeking peptides by the Eisenberg plot and assumed to exist as aggregates of 3–4 molecules. Interestingly, grammistin Gs 2 is much more abundant in amphiphilic α-helices and much higher in biological activities than melittin and pardaxins as well as grammistin Gs 1.

Cryptocaryon irritans (Ciliophora): primary infection in thick‐lipped mullet, Chelon labrosus (Risso)

Abstract. Cryptocaryon irritans (Ciliophora), isolated from the reef fish, Grammistes sexlineatus Thumberg, was established as primary infections in mullet, Chelon labrosus (Risso). Only a small percentage (<22%) of exposed theronts established infection under controlled conditions. This is discussed in relation to the probability of host parasite contact and susceptibility. There was no evidence of density‐dependent or intra‐specific competition in trophont establishment, a strong linear relationship being found between the levels of exposure and infection. Infection intensity was assessed in relation to host survival, indicating a 90% probability of host death following levels of >200 trophonts per gram of host. A close temporal association between host death and trophont exit was found, possibly as a result of epidermal disruption leading to dysfunction of osmoregulatory and respiratory systems.

Cryptocaryon irritans Brown, 1951 (Ichthyophthiriidae): the ultrastructure of the somatic cortex throughout the life cycle

Abstract. Cryptocaryon irritans was isolated from Grammistes sexlineatus and maintained in aquaria under controlled conditions using the mullet, Chelon labrosus (Risso), as an experimental host. The pellicle and cortical cytoplasm of the trophont, tomont, tomite and theront stages were investigated with the aid of transmission electron microscopy. The general structural organization of the pellicle resembles that of the freshwater holotrich, Ichthyophthirius multifiliis; however, the pellicular alveoli are characterized by the accumulation of electron‐dense material in the trophont, tomite and theront, this material being lost in the newly‐encysted tomont. The outer membranes of the pellicle are infolded into the alveoli of the trophont. Cilia are present at all stages of the life cycle, although at encystment their numbers are greatly reduced by shedding. Mitochondria, mucocysts and Golgi‐like cisternae are distributed throughout the cortical cytoplasm. Mucocysts differ from those of I. multifiliis in size, shape and distribution and are of uniform electron density. The role of the pellicle and cortical cytoplasm is discussed in relation to the invasion of the fish epidermis, possible intertransferance of materials between parasite and host and the process of encystment.

ヌノサラシ科4魚種のgrammistin成分の比較

Grammistins of Grammistes sexlineatus, Diploprion bifasciatum and Aulacocephalus temmincki were fractionated by Sephadex LH-20 column chromatography and countercurrent distribution, and compared with those obtained from Pogonoperca punctata. Three grammistin components corresponding to grammistins A, B and C of P. punctata were separated from G. sexlineatus, suggesting a close relationship between these two species. Grammistins of D. bifasciatum and A. temmincki revealed a very different pattern of elution and distribution from those of P. punctata. The major grammistin from A. temmincki was a fairly large molecule. In addition to the four grammistins, D. bifasciatum contained a large amount of a fat soluble hemolysin, which was a small tertiary or quaternary amine without a peptide moiety.

Occurrence of a toxic substance in the skin of a sea bass Pogonoperca punctata

The skin of the sea bass Pogonoperca punctata was found to contain a toxic substance. It caused ciguatera-like effects in cats and showed a resemblance in its pharmacological properties to the toxin from a soapfish, and pahutoxin from a boxfish. It was soluble in acidic water, 70 per cent ethanol, n-butanol and n-amyl alcohol, and insoluble in most fat solvents. It was dialyzed very slowly and precipitated nearly quantitatively as a complex at a half-saturation with NaCl or (NH 4) 2SO 4. On thin-layer chromatography, the preparation partially purified by precipitation with NaCl and subsequent extraction with n-butanol consisted of four or five toxic components, each positive to the Dragendorff reagent and negative to both the biuret and ninhydrin reagents. A toxin obtained from the secretions of another sea bass, Grammistes sexlineatus, was almost identical. A wide distribution of a similar toxin in members of the subfamily Grammistinae is suggested.