EcoZone: Jellyfish Facts
The most poisonous jellyfish, and indeed probably the most venomous marine creature, is the sea wasp or box jellyfish(Chironex fleckeri Southcott) from Australia. An adult is said to have enough poison to be able to kill sixty people, and swimmers do die after being sting by it (at least seventy people killed in the last 100 years). Death comes quickly (four minutes) from the toxin that acts on the heart. Apparently sea wasps can’t sting through tights – so, girls, keep your stockings on if you are paddling in box jellyfish land!
Some jellyfish contain algae (microscopic plants) which photosynthesise and produce carbohydrates which the jellyfish can absorb. The algae, in return, get a safe and stable microhabitat (a kind of jelly greenhouse!) in which to live. This relationship between organisms where both partners benefit is called symbiosis (literally “living together”). One example is the upside-down jellyfish (Cassiopeia xamachana Bigelow) which contains a population of the microscopic alga Symbiodinium microadriaticum Freudenthal within its tissues. The algae release nutrients which the jellyfish absorbs. If the algae die, the jellyfish may waste away, consuming its own body.
Jellyfish are primitive: they have no true eyes, heart, bones or other solid organs. They don’t have a brain but just a network of nerves that enable them to react to their environment, sensing “light”, “dark”, “up”, “down”, etc. We know that jellyfish have been on earth for at least 650 million years.
Most jellyfish are marine and they are found in all the world’s oceans. A few live in lentic (still) fresh water such as inland lakes.
Jellyfish swim by jet propulsion: their bodies pulse rhythmically to push them forward. They can also travel thousands of kilometres on sea currents or blown by the wind. Sometimes thousands or even millions are washed up on beaches.
The largest jellyfish can attain a diameter of almost 2.5 metres. The species with the longest tentacles is the lion’s mane (Cyanea capillata (Linnaeus)), made famous by Sir Arthur Conan Doyle’s Sherlock Holmes story. It is to be found in colder seas, including those around Britain, and in arctic waters. Its tentacles can be 30 metres long.
A jellyfish uses its sting to kill or stun prey. The stinging cells contain tiny capsules or nematocysts which can fire a minute barbed dart to deliver their poison. If a person is stung, don’t rub the sting and provoke more nematocysts to fire! Vinegar poured on liberally to flood the affected area immediately is should help to inhibit the firing of the nematocysts. Advice often given is to follow this by gently rubbing the area with fresh juicy papaya (pawpaw – Carica indica) or a proprietary meat tenderiser mixed with a little water which should aid in destroying the poison. (Meat tenderisers contain the enzyme papain from papaya that breaks down other proteins - the poison is a protein.) The immediate application of hot (not scalding!) water to flood the sting (or just sea water if there is nothing else) and a speedy trip to the doctor or hospital is probably as good advice as any. Like all stings, remember that a serious allergic reaction is a possibility. If you can identify or get a sample of the jellyfish (very carefully!) this makes the right treatment easier. In Australia, lifeguards may carry antivenin for the dangerous box jellyfish - and fast expert treatment is really, really important!
And here is something from the internet for our more advanced readers about papain, which is the active ingredient in many meat tenderisers:
Papain is a sulfhydryl protease from Carica papaya latex. A second protease, chymopapain, and a lysozyme have also been isolated from this plant. Since native crystalline papain is quite unreactive until acted upon by mild reducing agents such as cysteine or cyanide, it may exist as a zymogen. For a general review, see Liener (1974). Barrett and Buttle (1985), Polgár (1984) and Brocklehurst and Salih (1983) report on the classification of papaya latex proteinases. Papain has wide specificity. In her review, Arnon (1970) has indicated that it will degrade most protein substrates more extensively than the pancreatic proteases. It is also an esterase. Papain has been reviewed by Smith and Kimmel (1960). It has been reported by Sluyterman and Wijdenes (1972) that the action of papain on leucine methyl ester produces an insoluble polyleucine peptide. The finding of Thomas (1956) that papain breaks down the intercellular matrix of cartilage (see also McCluskey and Thomas 1958), led to its further study as a chondromucoproteinase (Smith et al. 1962). Proteolytic enzymes are widely used in cell isolation. With some tissues papain has proved less damaging and more effective than other proteases. Lam (1972) found that of the enzymes used for dissociating turtle retina, papain produced the least trauma. Intact single photoreceptor cells have also been isolated from adult salamander retina with papain (Bader et al. 1978, Townes-Anderson et al. 1985). Huettner and Baughman (1986) descrbed a method using papain to obtain high yields of viable, morphologically intact cortical neurons from postnatal rats. Finkbeiner and Stevens (1988) applied the Huettner and Baughman method to the dissociation of postnatal rat hippocampus. Papain is used with fetal as well as postnatal brain regions to provide maximal dissociation and viability of neurons.
Characteristics of Papain from Carica papaya:
• Molecular weight: 23,000 (Dreuth et al. 1968).
• Composition: Papain is a single peptide chain of 211 residues folded into two parts that form a cleft (Dreuth et al. 1968). A three-dimensional structure has been indicated by Wolthers et al. (1970). The molecule has one free SH group which is functional (Smith et al. 1975; Shipton et al. 1975). According to Alecio et al. (1974) there are seven subsites each capable of accommodating a single amino acid residue of a peptide substrate. See also Glick and Brubacker (1974). Other reports on molecular information and its relation to activity are as follows: Fink and Gwyn (1974), Lewis and Shafer (1974), Akalski et al. (1973), Allen and Lowe (1973), Brocklehurst and Little (1973), Mole and Horton (1973), Banks and Shafer (1972), Brocklehurst et al. (1972), Campbell and Kaiser (1971, 1972), Sluyterman and Wijdenes (1972), Hinkle and Kirsch (1971) Jori et al. (1971), Lowe and Yuthavong (1971) and Steiner (1971).
• Optimum pH: 6.0 - 7.0.
• Extinction coefficient: = 25.0 (Mitchel et al. 1970).
• Isoelectric point: pH 9.6 (Sluyterman and DeGraff 1972).
• Activators: Papain is activated by cysteine, sulfide, sulfite, etc. It is enhanced when heavy metal binding agents such as EDTA are also present. Kirschenbaum (1971) indicated that N-bromosuccinimide enhances the activity. Hall et al. (1972) report on the affects of acridine dyes.
• Inhibitors. Substances which react with sulfhydryl groups including heavy metals, carbonyl reagents (Morihara 1967). Westerik and Wolfenden (1972) have studied aldehydes as papain inhibitors and Sluyterman and Wijdenes (1973) report on benzoylamidoacetonitrile as an inhibitor. See Shapira and Arnon (1967) on antibody inhibitors. Papain may be inactivated by H2O2 generated by [[gamma]]-irradiation of H2O- the active SH group being oxidized to sulfenic acid. (Lin et al 1975). See also Allison and Swain (1973).
• Stability. Papain as a crystalline suspension is stable at 5°C for 6-12 months. Stabilizing agents are EDTA, cysteine and dimercaptopropanol.
• To enhance stability as well as solubility it may be advantageous to convert crystalline papain to its mercury derivative (Brubacher and Bender 1966).
Assay
• Method. A titrimetric determinatin of the acid produced during the hydrolysis of benzoyl-L-arginine ethyl ester (BAEE). One unit will hydrolyze one micromole of benzoyl-L-arginine ethyl ester per minute at 25°C and pH 6.2 under the specified conditions.
• Reagents. Enzyme diluent (Activation buffer): Prepare fresh daily by mixing the following:
0.01 M EDTA 10 ml 0.06 M Mercaptoethanol 0.1 ml
0.05 M Cysteine HCl 10 ml
Reagent grade water 70 ml
• Substrate solution: Prepare fresh daily by mixing the following:
0.058 M BAEE 15.0 ml
0.01 M EDTA 0.8 ml
0.05 M Cysteine HCl 0.8 ml
• Adjust pH to 6.2 and dilute to a final volume of 21 ml with reagent grade water.
• Titrant: 0.01-0.02 N NaOH, standardized
• Enzyme. Activate enzyme by dissolving in enzyme diluent to a concentration of 0.05-0.1 mg/ml. Under these conditions activation is complete within 30 minutes.
• Determination of protein concentration
•
• Procedure. The reaction can be measured with either an automatic titrator or a laboratory pH meter. The titration vessel should be maintained at 25°C.
• Pipette the following into the titration vessel at 25°C:
Substrate solution 5.0 ml
3.0 M NaCl 5.0 ml
Reagent grade water 5.0 ml
• At zero time add 0.1 ml of appropriately diluted enzyme and adjust the pH to 6.2. Record the amount of standardized NaOH added per minute to maintain the pH at 6.2 after a constant rate is achieved.
• Calculation
• Technical note: Mercuripapain must be activated before use. Mercury is removed from the enzyme in activation buffer. After 30 minutes in this solution, the enzyme is completely activated and the mercury has been chelated. The mercuripapain suspension contains no free mercury. The product has been extensively dialyzed prior to packaging.