Sections of hydra studied with the electron microscope show various structures which have been identified by referring to control histological sections and to previous descriptions. Certain features have also been examined in frozen-dried sections under the light microscope. In the ectoderm, epithelio-muscular cells contain various organelles, and also smooth longitudinal muscle-fibres with whi...

Sulfur-containing compounds are important components of all organisms, but few studies have explored sulfate utilization in corals. Our previous study found that the expression of a sulfur transporter (SLC26A11) was upregulated in the presence of Symbiodinium cells in juveniles of the reef-building coral Acropora tenuis In this study, we performed autoradiography using (35)S-labeled sulfate ion...

Phospholipase A2 (PLA2) is an enzyme present in snake and other venoms and body fluids. We measured PLA2 catalytic activity in tissue homogenates of 22 species representing the classes Anthozoa, Hydrozoa, Scyphozoa and Cubozoa of the phylum Cnidaria. High PLA2 levels were found in the hydrozoan fire coral Millepora sp. (median 735 U/g protein) and the stony coral Pocillopora damicornis (693 U/g...

We have isolated and characterized a novel hemolytic protein from the venom of the Hawaiian box jelly®sh (Carybdea alata). Hemolysis of sheep red blood cells was used to quantitate hemolytic potency of crude venom extracted from isolated nematocysts and venom after fractionation and puri®cation procedures. Hemolytic activity of crude venom was reduced or lost after exposure to the proteolytic e...

Fishing tentacle nematocysts of the hydrozoan, Physalia utriculus, from Hawaiian coastal waters, were examined by light microscopy, as well as by scanning and transmission electron microscopy (SEM and TEM). Hawaiian P. utriculus has been assumed to be conspecific with the Australian morph based on general macroscopic descriptions. Ultrastructural examination using SEM and TEM revealed that the ...

OBJECTIVE To determine the effect acetic acid (vinegar) has on discharged nematocysts in a simulated sting from Chironex fleckeri. METHOD This research was performed in 2 parts: 1 C. fleckeri tentacles placed on amniotic membrane were electrically stimulated, and venom washings collected before and after application of vinegar. Lyophilised venom washings were run through a fast-performance pr...

A previous electron microscopic study of the cat testis revealed that spermatids derived from the same spermatogonium are joined together by intercellular bridges. The present paper records the observation of similar connections between spermatocytes and between spermatids in Hydra, fruit-fly, opossum, pigeon, rat, hamster, guinea pig, rabbit, monkey, and man. In view of these findings, it is c...

The deadly box jellyfish (Sea Wasp, Habu-kurage in Japanese) Chiropsalmus quadrigatus Haeckel (Cubozoa) is distributed widely in the tropical Pacific region. In Japan, three fatal cases due to stings from this species have been reported officially. We successfully isolated C. quadrigatus toxin-A (CqTX-A, 44 kDa), a major proteinaceous toxin, for the first time, from the nematocysts of C. quadri...

STUDY OBJECTIVE We describe Irukandji syndrome (a painful hypercatecholaminergic condition caused by jellyfish envenoming) in Australia's Northern Territory. METHODS We collected prospectively a standardized data set on patients presenting to health facilities in the Northern Territory. Additional cases were identified retrospectively. Data collected included demographic, geographic, seasonal...

The Myxozoa comprise over 2,000 species of microscopic obligate parasites that use both invertebrate and vertebrate hosts as part of their life cycle. Although the evolutionary origin of myxozoans has been elusive, a close relationship with cnidarians, a group that includes corals, sea anemones, jellyfish, and hydroids, is supported by some phylogenetic studies and the observation that the dist...