It is well known that exosomes could serve as anti-microbial immune factors in animals. However, despite growing evidences have shown that the homeostasis of the hemolymph microbiota was vital for immune regulation in crustaceans, the relationship between exosomes and hemolymph microbiota homeostasis during pathogenic bacteria infection has not been addressed. Here, we reported that exosomes released from Vibrio parahaemolyticus-infected mud crabs (Scylla paramamosain) could help to maintain the homeostasis of hemolymph microbiota and have a protective effect on the mortality of the host during the infection process. We further confirmed that miR-224 was densely packaged in these exosomes, resulting in the suppression of HSP70 and disruption of the HSP70-TRAF6 complex, then the released TRAF6 further interacted with Ecsit to regulate the production of mitochondrial ROS (mROS) and the expression of Anti-lipopolysaccharide factors (ALFs) in recipient hemocytes, which eventually affected hemolymph microbiota homeostasis in response to the pathogenic bacteria infection in mud crab. To the best of our knowledge, this is the first document that reports the role of exosome in the hemolymph microbiota homeostasis modulation during pathogen infection, which reveals the crosstalk between exosomal miRNAs and innate immune response in crustaceans.
A great variety of parasites and parasitoids exploit ant societies. Among them are the Mesostigmata mites, a particularly common and diverse group of ant-associated arthropods. While parasitism is ubiquitous in Mesostigmata, parasitoidism has only been described in the genus Macrodinychus. Yet information about the basic biology of most Macrodinychus species is lacking. Out of 24 formally described species, information about basic life-history traits is only available for three species. Here we formally describe two new Macrodinychus species, i.e. Macrodinychus hilpertae and Macrodinychus derbyensis. In both species, immature stages developed as ecto-parasitoids on ant pupae of the South-East Asian army ant Leptogenys distinguenda. By piercing the developing ant with their chelicera, the mites apparently suck ant hemolymph, ultimately killing host individuals. We compare infection rates among all studied Macrodinychus species and discuss possible host countermeasures against parasitoidism. The cryptic lifestyle of living inside ant nests has certainly hampered the scientific discovery of Macrodinychus mites and we expect that many more macrodinychid species await scientific discovery and description.
We report a series of dermatitis cases caused by the staphilinid beetles, Paederusfuscipes Curtis, among university students staying in the residential college in Puncak Alam, Selangor, Malaysia from 1 January to 31 December 2010. A total of 360 cases (6.0%) were recorded in the Student Health Center throughout the year; the majority of patients stayed at a hostel near an oil palm plantation. Skin symptoms included erythema, edema, vesicular papules, painful blisters, burning sensation, pruritus, hyper pigmentation and peeling of skin. The commonly involved sites were the face, neck, shoulders and arms. Most students noticed the symptoms upon awakening in the morning. The patients were treated with fusidic acid cream and the symptoms resolved within 5 days. These beetles are nocturnally active and enter the room whenever a light source is available. The unintentional crushing of these beetles during sleep causes the release of its hemolymph (paederin) which is the cause of the dermatitis.
Sex pheromonal components of the tephritid fruit fly Bactrocera dorsalis (Hendel), 2-allyl-4,5-dimethoxyphenol and (E)-coniferyl alcohol, are biosynthesized from a highly potent male attractant, methyl eugenol, then sequestered and stored in the rectal gland prior to their release during courtship at dusk. These sex pheromonal components have been detected in the haemolymph and crop organ. Hence, attempts were made to separate and identify the haemolymph fractions which contained the sex pheromonal components. Identification of these bioactive fractions in methyl eugenol-fed male flies using gel filtration column chromatography and biodetection using live male flies showed two fractions as highly attractive to conspecific males. These fractions show a significant increase in protein absorbance in the elution profile of haemolymph from methyl eugenol-fed males compared with that from methyl eugenol-deprived males. The molecular mass of these bioactive fractions as determined by using gel filtration was in the peptide range of 3.3 to 5.5 kDa. Subsequent gas chromatography-mass spectrometry analyses further confirmed the presence of the pheromonal components in the bioactive fractions. The presence of these methyl eugenol-derived sex pheromonal components in specific haemolymph fractions suggests the involvement of a sex pheromone binding complex.
Males of Bactrocera dorsalis (Diptera: Tephritidae) are attracted strongly to and feed compulsively on methyl eugenol (1,2-dimethoxy- 4 -(2-propenyl)benzene), a highly potent male attractant. Pharmacophagy of methyl eugenol results in the production of phenylpropanoids 2-allyl-4,5-dimethoxyphenol and (E)-coniferyl alcohol that are sequestered and stored in the rectal gland prior to release as sex pheromonal components during mating at dusk. While these pheromonal components have also been detected in the hemolymph and crop of methyl eugenol-fed males, there is currently little information on the transport of these compounds from the crop to rectal gland in male B. dorsalis. Therefore, using physiological techniques such as parabiosis, rectal gland transplantation and hemolymph transfusion coupled with gas chromatography-mass spectrometry (GC-MS) analyses, we were able to ascertain and confirm the role of the hemolymph in the transport of these sex pheromonal components from the crop to the rectal gland. Further, the temporal profile of these methyl eugenol-derived bioactive compounds in the hemolymph also shows an increase with time post-methyl eugenol-feeding, i.e., 2-allyl-4,5-dimethoxyphenol attaining maximum amounts 15 min after ME consumption and decreasing thereafter, while for (E)-coniferyl alcohol-the increase and decrease are more gradual. These results further demonstrate the ability of insect hemolymph to transport many diverse forms of bioactive molecules including attractant-derived sex pheromonal components.
Natural peptides in insect vectors played an important role in the control of
pathogens. Musca domestica Linnaeus and Chrysomya megacephala Fabricius were
two species of local fly chosen to detect presence of antimicrobial peptide substance.
The screening of the antimicrobial activity was carried using a spectrophotometric
method. Results were obtained much quicker and less laborious. The results showed
larva hemolymph of M. domestica lysed Bacillus subtilis and two Gram negatives,
Escherichia coli and Pseudomona. aeruginosa. The pupae hemolymph only lysed E.
coli. Whereas, the hemolymph of C. megacephala larva showed bactericidal effect
against both of the Gram positives tested, i.e. B. subtilis and Staph. aureus. and no
effect was against the Gram negatives. The pupa showed lytic activity against Staph.
aureus and P. aeruginosa. As a conclusion, the larva and pupa hemolymph of M.
domestica and C. megacephala demonstrated antibacterial activity. However, larva
hemolymph of M. domestica and C. megacephala has broader antibacterial activity
against both Gram positive and negative bacteria.
The present datasets were conducted to investigate glucose concentration in hemolymph, energy levels at selected body parts (hepatopancreas, muscle, gonad), and feces among different sexes of crabs cultured at four different water velocities (0, 20, 40, and 60 cm/s) during a 60-day culture period. A total of 102 immature crabs (51 males, and 51 females) were sampled from Kuala Muda, Kedah coastal water, Peninsular Malaysia (5°39'N 100°19'E) from April to November of 2018. Results indicated that glucose concentration was the highest at water velocity of 60 cm/s for both male and female crabs (♂: 3.76 ± 0.08 mmol/L; ♀: 3.63 ± 0.06 mmol/L), whereas at 0 cm/s, the lowest levels of glucose concentration (♂: 0.13 ± 0.08 mmol/L; ♀: 0.19 ± 0.06 mmol/L) were recorded. As for energy analysis in hepatopancreas, results showed that both male and female crabs recorded the highest levels at 0 cm/s (no flow) with 37.919 ± 0.07 KJ/g and 34.636 ± 0.50 KJ/g, respectively. Energy for locomotion (muscle) of male crabs recorded the highest at 0 cm/s (♂: 26.823 ± 0.06 KJ/g), meanwhile for females, the highest was recorded at 20 cm/s (26.607 ± 0.34 KJ/g). Energy for reproduction of males could not be compared due to an insufficient available amount of testes/vas deferens, whereas female crabs recorded the highest energy usage at 20 cm/s water velocity (♀: 37.895 ± 0.08 KJ/g). For feces, both male and female crabs recorded the lowest energy at 60 cm/s (♂: 5.841 ± 0.03 KJ/g; ♀: 5.393 ± 0.01 KJ/g). Glucose assessment showed a direct relationship between increased velocity and glucose secretion in hemolymph at high velocity of 60 cm/s (stress condition) compared to other treatments. Regarding energy analysis, this research improved the mechanism of hepatopancreas, gonad, muscle and feces functions in development and reproduction, while it shed light on the influence of velocity on energy metabolism of S. olivacea.
Pharmacophagy of methyl eugenol (ME)--a highly potent male attractant, by Bactrocera papayae results in the hydroxylation of ME to sex pheromonal components, 2-ally-4,5-dimethoxyphenol (DMP) and (E)-coniferyl alcohol (CF). These compounds, which are also male attractants, are then sequestered and stored in the rectal gland prior to their release during courtship at dusk. Chemical analyses of the digestive tract (excluding the crop and rectal gland) showed the absence of the sex pheromonal components and their precursor, ME. However, B. papayae males were attracted to and fed on the ME-fed male hemolymph extracts but not on hemolymph extracts of ME-deprived males. After thin layer chromatography in a hexane:ethyl acetate solvent system, flies were attracted to and fed on the original point on the TLC plate where the hemolymph extract had been spotted, suggesting that the pheromone components were bound in polar complexes. Chemical analyses of the ME-fed male hemolymph and crop extracts revealed the presence of the sex pheromonal components. The presence of the ME-derived pheromonal components and the absence of ME in the hemolymph suggest that the hemolymph is involved in the transportation of sex pheromonal components from the crop to the rectal gland.
The evolution of multiple-drug resistant bacteria is contributing to the global antimicrobial crisis, hence driving us to search for novel antimicrobial(s). Among animals, invertebrates represent up to 80% of all known species suggesting their wide distribution. Despite their ubiquitous and plentiful nature, they have been largely unexplored as potential source of antibacterials. In this study, we selected a broad range of invertebrates from terrestrial and marine environments and tested their lysates for antibacterial activity against methicillin-resistant Staphylococcus aereus (MRSA) and neuropathogenic Escherichia coli K1. Cockroaches, centipedes, tarantulas, prawns, lobster, and mud crabs showed antibacterial activity with selected lysates exhibiting more than 90% bactericidal effects. The red-headed centipede's hemolymph showed 90% and 50% bacteriostatic activity against MRSA and E. coli K1, respectively. Tarantula's body extracts exhibited antibacterial activity against MRSA and E. coli K1. Gut extracts of tiger prawn exhibited more than 90% bacteriostatic activity against both bacteria. The selected lobster and mud crab extract exhibited up to 90% growth inhibitory activity against MRSA. Overall, these results showed that selected invertebrates are an untapped source of broad-spectrum antibacterial activity and suggest the presence of biologically active molecules.