Hepcidin, initially identified in human blood ultrafiltrate as cysteine rich Liver Expressed Antimicrobial Peptide (LEAP-1), is a core molecular conduit between iron trafficking and immune response. ...Though a great share of studies has been focused on the iron regulatory function of hepcidins, investigations on the antimicrobial aspects are relatively less. The present study is aimed at identification of hepcidin from a teleost fish, Alepes djedaba followed by its recombinant expression, testing antibacterial property, stability and evaluation of cytotoxicity. Modes of action on bacterial pathogens were also examined. A novel hepcidin isoform, Ad-Hep belonging to the HAMP1 (Hepcidin antimicrobial peptide 1) group of hepcidins was identified from the shrimp scad, Alepes djedaba. Ad-Hep with 2.9 kDa size was found to be a cysteine rich, cationic peptide (+4) with antiparallel beta sheet conformation, a furin cleavage site (RXXR) and ‘ATCUN’ motif. It was heterologously expressed in E. coli Rosettagami B(DE3)PLysS cells and the recombinant peptide, rAd-Hep was found to have significant antibacterial activity, especially against Edwardsiella tarda, Vibrio parahaemolyticus and Escherichia coli. Membrane depolarization followed by membrane permeabilization and Reactive Oxygen Species (ROS) production were found to be the modes of action of rAd-Hep on bacterial cells. Ad-Hep was found to be non-haemolytic to hRBC and non-cytotoxic in mammalian cell line. Stability of the peptide at varying temperature, pH and metal salts qualify them for applications in vivo. With significant bactericidal activity coupled with direct killing mechanisms, the rAd-Hep can be a promising drug candidate for therapeutic applications in medicine and fish culture systems.
•A novel hepcidin isoform, Ad-Hep was isolated from the shrimp scad, Alepes djedaba.•The 2.92 kDa Ad-Hep was cysteine-rich and cationic (+4) with 4 disulfide bonds.•rAd-Hep inhibited Edwardsiella tarda, Vibrio parahaemolyticus and Escherichia coli.•rAd-Hep effected membrane permeabilization and reactive oxygen species production.•Ad-Hep was non-haemolytic to hRBC and non-cytotoxic to normal cell line (CHO-K1).
Carangidae are ecologically and economically important marine fish. The complete mitogenomes of three Carangidae species (
,
, and
) were sequenced, characterized, and compared with 29 other species ...of the family Carangidae in this study. The length of the three mitogenomes ranged from 16,530 to 16,610 bp, and the structures included 2 rRNA genes (
and
), 1 control region (a non-coding region), 13 protein-coding genes, and 22 tRNA genes. Among the 22 tRNA genes, only
(GCT) was not folded into a typical cloverleaf secondary structure and had no recognizable DHU stem. The full-length sequences and protein-coding genes (PCGs) of the mitogenomes of the three species all had obvious AT biases. The majority of the AT-skew and GC-skew values of the PCGs among the three species were negative, demonstrating bases T and C were more plentiful than A and G. Analyses of Ka/Ks and overall p-genetic distance demonstrated that
showed the highest evolutionary rate and
/
were the most conserved genes in the three species. The phylogenetic tree based on PCGs sequences of mitogenomes using maximum likelihood and Bayesian inference analyses showed that three clades were divided corresponding to the subfamilies Caranginae, Naucratinae, and Trachinotinae. The monophyly of each superfamily was generally well supported. The divergence time analyses showed that Carangidae evolved during three geological periods, the Cretaceous, Paleogene, and Neogene.
began to differentiate from other species about 27.20 million years ago (Mya) in the early Miocene, while
(21.25 Mya) and
(14.67 Mya) differentiated in the middle Oligocene.
Objective: To evaluate the stock of Alepes djedaba (A. djedaba) by describing the length composition, growth parameters, mortality rates of A. djedaba captured in Arabian Gulf off Saudi Arabia and ...adopting yield per recruit and biomass per recruit models. Methods: A random sample of 490 fish representing a moderate range of total lengths (16.5-32.4 cm) and weights (60-410 g) were sampled in Arabian Gulf off Dammam, Saudi Arabia during the period from August 2008 to July 2009. LFD5 software was used for estimation of growth parameters. Total mortality was calculated using the length converted catch curve. Natural mortality was estimated using Pauly and David's formula. Fishing mortality was computed by subtracting natural mortality from total mortality. Per recruit analysis was made using Beverton and Holt model. Results: Length-frequency analysis revealed four peaks and the length range from 22 cm to 27 cm dominated the catch, constituting about 71% of the catch. Values of the von Bertalanffy growth parameters were computed using LFD5 software as follows: the asymptotic length (L sub(infinity))=41.71 cm, curvature parameter (K)= 0.36 year super(-1), and hypothetic age at zero length (t sub(a) = -0.76 year. The total mortality (Z) was estimated as 2.07 year super(-1), and natural mortality was 0.8 year super(-1). Fishing mortality F=1.27 year super(-1), which was higher than F sub(a.1) (0.3 year super(-1)), F sub(SB(sa)) (0.59 year super(-1)) and F sub(SB(a0)) (0.86 year super(-1)). At the current levels of fishing and natural mortality, the biomass per recruit is 34% of the virgin biomass. Conclusions: These may indicate an overexploitation state of the fisheries of A. djedaba in Arabian Gulf.
In order to optimize the size selectivity of demersal trawl targeting Banded Scad, Alepes djedaba, in the South China Sea (SCS), we tested and compared the selective properties of four experimental ...codends. These codends included two diamond-mesh codends (T0 codends) with different mesh openings (30 and 35 mm), and two T90 codends (the netting was turned by 90 degrees) with the relatively same mesh opening. The results demonstrated that the T0_30 codend (diamond-mesh codend with 30-mm mesh opening) presented the best size selectivity and is a potential choice to harvest Banded Scad in the studied area among the codends tested. Although applying the T0_35 or T90_30 codend might obtain a little improvement in size selectivity, the loss of marketable-size individuals could be a compromise. Considering the results in our study and those of previous studies, we recommend that the T0_30 codend should be mandated in the fisheries management regulation of trawl fisheries targeting Banded Scad in the SCS.
Our observations on scyphomedusae from selected Philippine embayments identified specific animals commensal with five species of rhizostome scyphomedusae,
Acromitoides purpurus
,
Mastigias
sp.,
...Phyllorhiza punctata, Rhopilema hispidum
and
Versuriga anadyomene. Acromitoides purpurus
medusae harbor the crab
Charybdis feriata
, the carangid fish
Alepes djedaba
and the poecilostomatoid copepod
Paramacrochiron
sp. The carangid
A. djedaba
was an associate of the blue morph of
A. purpurus
and
Rhopilema hispidum
in Panguil Bay. A black-pigmented
Alepes
sp. was found associated with burgundy
A. purpurus
medusae in Carigara Bay.
Charybdis feriata
juveniles are common commensals of all morphs of
A. purpurus
,
R. hispidum
and
P. punctata
medusae
.
Only the zooxanthelate
Mastigias
sp. lacked animal symbionts. We invoke the “meeting-point hypothesis” and the general theory of fish aggregation to floating structures to explain fish symbiosis with their medusan hosts. The invertebrate-medusa associations are attributed to feeding behaviors and predator avoidance by resident commensals. This study provides record of the poorly studied scyphozoan species and their association with animals in Philippine waters. Finally, we discuss the potential reasons why the golden spotted jellyfish,
Mastigias
sp., appears to lack animal commensals.
A wide variety of fish and invertebrates are associated with marine jellyfishes, and their interactions are diverse. We preliminarily investigated symbionts on two species of rhizostome jellyfishes ...collected from Leyte and Palawan Islands, the Philippines, in August 2013. The collected jellyfishes were Lobonemoides robustus Stiasny on both islands and Acromitus maculosus Light on Palawan Island. Lobonemoides robustus is commercially harvested on both islands, and seems to have been previously misidentified as Lobonema smithi Mayer. The associated fish juveniles on these hosts were identified as Alepes djedaba (Forsskål) and Carangoides equula (Temminck & Schlegel). Alepes djedaba is closely associated with many species of scyphozoan jellyfish broadly in the southeastern Asian waters. The associations of carangids with jellyfish are also reviewed.
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