Giant Earthworm Research Articles

Conservation of native earthworms and the role of the Giant Gippsland Earthworm as a flagship taxon

Conservation of native earthworms and the role of the Giant Gippsland Earthworm as a flagship taxon

Spectroscopic studies of the met form of the extracellular hemoglobin from Glossoscolex paulistus

Sephadex G-200 chromatography of the extracellular hemoglobin from the giant earthworm G. paulistus in the met form presents a single peak at pH 7.0 and two peaks at pH 9.0 as a result of alkaline dissociation. SDS-PAGE shows that the polypeptide chains are very similar to those observed for the oxy form and the two peaks at pH 9.0 correspond to the trimer contaminated by linkers and monomers which seems to be quite pure. The aquomet acid form is stable as an oligomer of molecular mass 3.1 × 10 6 Da only in a narrow pH range around neutrality. Increasing the pH above 7.5 leads to an irreversible transition from aquomet to hemichrome I which is the low-spin bis-imidazole complex. At pHs above 9.5–10.0 a second reversible transition takes place from hemichrome I to hemichrome II, a high-spin complex which is associated with the weakening and possible disruption of the proximal FeN histidine bond. Thus, increase in pH above 8.0 induces changes in the heme pocket that involve both the distal and proximal sides of the heme. EPR measurements show a very sharp decrease of the aquomet high-spin signal in the range of pH 7.0–8.0 and a very small low-spin signal even at liquid helium temperatures. The transition to hemichrome I is also accompanied by the loss of heme optical activity monitored by CD, which is consistent with the weakening of heme-globin interaction. Hemichrome I in the presence of cyanide gives the typical cyanometHb derivative which has a transition to a hemichrome at much higher pHs. This observation suggests that the dissociation of the oligomer in alkaline medium as well as the stability of the heme on the proximal side, depend both upon the ligand present at the sixth coordination position on the distal side. Hence, we believe that hemi(hemo)chrome formation in G. paulistus Hb and other invertebrate hemoglobins is a common phenomenon, not associated with protein denaturation, which may provide a fine tuning mechanism to control subunit interactions through changes in the distal side of the heme pocket.

Reproductive-Biology of Megascolides Australis Mccoy (Oligochaeta, Megascolecidae)

Observations of gametogenesis facilitated understanding life history and reproductive processes in Megascolides australis, whose reproductive strategies are correlated with longevity, low density and poor dispersal ability. Worms are biparental and have a discrete breeding (egg laying) season in spring and summer. This coincides with the greatest number of mature ova and the glandular epidermis of the clitellar region being thickest. Gametogenesis occurs throughout the year, with sperm present in the spermathecae and available on male funnels ail year. Non-seasonal copulation may occur when two worms meet and conditions are favourable; this trait is advantageous for species in low densities with poor dispersal abilities. The spermathecal structure of M. australis differs from that of other megascolecids recorded in that the structure of the diverticulum includes many multiloculate chambers that do not connect directly with the spermathecal duct. The sperm form orientated bundles (spermatozeugmata) not previously described for Megascolecidae and are stored in the ampulla rather than the diverticula.

Circulation in the Gippsland Giant EarthwormMegascolides australis

Pressures have been measured in the dorsal vessel (DV), ventral vessel (VV), and lateral hearts (LHs) of the giant earthworm, Megascolides australis. Mean pressure in the DV (22.1 ± 9.8 cm H₂O ± 1 SD) was similar to that in the VV (21.8 ± 10.1 cm H₂O) although pressures were much more pulsatile in the DV than VV. Peak and minimum pressures in the DV were significantly above and below, respectively, those in the VV Contraction frequency of the DV was 6. 8 ± 1.9 ‧ min⁻¹. Neither imposing an orthostatic load by raising or lowering the tail, nor simulated autotomy, had any effect on pressure measured in the anterior segments of the worm. Injecting the $tracer^{99m}technetium$ into the anterior of the worm revealed that the circulation has two compartments; blood flow was rapid in the anterior 15 or 20 segments and exceptionally slow in the rest of the worm despite high blood pressure throughout the major distributing vessel, the VV. The anterior rapid circulation subserves the vital functions of the worm whil...

An analysis of the structure of the burrow system of the giant gippsland earthworm megascolides australis McCOY, 1878 using 3D-images

Megascolides australis, the giant earthworm of Gippsland (Victoria, Australia) is one of the larger earthworm inhabiting pasture soils. The burrow system has been partly described during summer; it shows a clear connected network structure with permanent burrows; long burrow (length >1.5m) and group of numerous short ones ranging from 20 to 110cm below the soil surface. A 3D representation, computed from field data, shows the patterns of this system, observed from different points. The structure of the system is discussed regarding the life cycle of this species.

The biology and conservation of the giant gippsland earthworm MEGASCOLIDES AUSTRALIS mccoy, 1878

Megascolides australis McCoy, 1878 is one of the world's largest earthworms and is restricted to a small area in South Gippsland, Victoria, Australia. It is listed by the IUCN as “vulnerable”. Adult worms average ca 750 x 20 mm and weigh upto 381 g. Three developmental (presumably age) classes have been found in the field based on the structure of the clitellum; young worms (mean 33 g), subadults (mean 69 g) and adults (mean 210 g). Adults form the dominant age class of the population at all times of the year, having densities up to four times those of immatures. Reproductively active adults were recorded mainly from September to December. Egg cocoons occur singly at an average depth of 220 mm and a density of 1.6 m -3. Incubation period is at least 12 months. Egg cocoons are 40–70 mm x 10–15 mm in size with an average weight of 9g. Worm distribution is patchy. Systematic sampling in a 2 × (1 × 1) km grid revealed worms in only 6% of the quadrats sampled. Over 80% of the occupied quadrats were within 40 m of the banks of streams or among soaks on south facing slopes. Prospects for conservation of the worm are discussed within the known framework of the species biology.

Biochemical studies on the giant earthworm Glossoscolex giganteus (Leuckart)

1. 1. The sodium, potassium, chloride, calcium, magnesium, inorganic phosphorus, sulphur, copper, bicarbonate, protein, urea, glucose, total lipids, copper oxidase activity, total iodine and protein-bound iodine contents of the blood of the giant earthworm Glossoscolex giganteus (Leuckart) were determined. 2. 2. The osmolarity of the blood was 181 mOsm/l. and the pH was 7·43. 3. 3. No alkaline phosphatase activity was detected in the blood, the uric acid contents being very low. 4. 4. The values for inorganic constituents in septal muscles, parietal muscles with cuticle, pseudo-hearts and faeces are given.

Biophysical and biochemical properties of earthworm-cuticle collagen

Cuticles from common night crawlers and a species of giant earthworm were extracted with acetic acid and purified. The collagenous extract was studied by means of electron microscopy, sedimentation velocity and equilibrium, viscosity, polarimetry, and amino acid analysis, in order to try to explain the lack of gross striated fibrils in the cuticles. It was confirmed that the native fibrils are unstriated, but they did become twisted when treated with formaldehyde. The soluble cuticle collagens were found to be composed of long fibrous particles about 5400 × 15 A ̊ , with molecular weights of about 640000. These particles are approximately twice the length, but otherwise similar in size and shape to vertebrate tropocollagens. The amino acid compositions of the earthworm collagens are qualitatively similar, but quantitatively different in some cases, from vertebrate collagens.

SCIENCE IN WESTERN SZECHUAN

II. BIOLOGICAL AND SOCIAL SCIENCES IN the preceding article* something has been said of the state of physics and chemistry in the five universities at the great city of west Szechuan, Chengtu. On the whole, the biological work there is even more active. On the West China Union (Huahsi) University campus some excellent taxonomic and ecological work is being done. Thus Dr. Chang Ming-Chun of Huahsi specializes on gastropod systematics and embryology, while Dr. Liu Cheng-Chao of Yenching is a really outstanding authority on Asiatic Amphibia. His collections and data are astonishing, including torrent adaptations, strange breeding habits, etc., and many new species, such as Vibrissaphora boringii, a whiskered frog. There are great opportunities for experimental embryology here, which have so far not been taken advantage of. Dr. Liu himself goes on collecting expeditions in the Tibetan borderlands which involve real hardship and danger. For comparative physiology also there are great opportunities, for example, to work with the giant earthworms of the Mount Omei region, species of Pheretima, commonly up to 3 ft. long and at least 1 in. in diameter.

The Giant Earthworm of Gippsland

IN the last issue of NATURE (p. 394) I observe in an article upon Megascolides australis that a supposition is expressed that very large earthworms will be found to occur in South America as well as in other continents. It may be of a little interest to mention that I found near the town of Manaos, in Amazonia, in the year 1874, an earthworm that measured 30 inches in length by ¾ inch in greatest breadth. When found, in the early morning, it was quite fresh, though newly dead, being somewhat crushed near one end, probably by some passer-by in the darkness. Unfortunately the worm spoiled in the rum in which I attempted to preserve it.

The Nephridia of Earthworms.

THE last number of the Quarterly Journal of Microscopical Science has just come into my hands, containing a paper, by Mr. Beddard, on the nephridia of certain earthworms. In November of last year I read a paper, before the Royal Society of Victoria, on the anatomy of the large Gippsland earthworm, Megascolides australis. This, which reaches the length of 6 to 8 feet, is, I believe, the largest recorded earthworm, and its nephridial system is of great interest, corresponding closely in many points to that described by Mr. Beddard, in the above paper, as present in Acanthodrilus multiporus and Perichaeta aspergilium. My drawings have been for some time in the lithographers' hands, but as it will still be one or two months before the full paper is published, I should be glad to draw attention to the, in some ways, still more interesting features of the nephridial system in Megascolides australis. The nephridia are very evident, and can be divided clearly into two sets.