A Comparison of the Effectiveness of Tri-N-Butyltin Chloride and Five other Organotin Compounds in Promoting the Development of Imposex in the Dog-Whelk, Nucella Lapillus

Author(s):  
G. W. Bryan ◽  
P. E. Gibbs ◽  
G. R. Burt

Populations of the common dog-whelk Nucella lapillus (L.) are declining or have already disappeared at many sites on rocky shores around the United Kingdom (Bryan et al. 1986). There is conclusive evidence that this is caused mainly by tributyltin (TBT) compounds leached from ships' antifouling paints (Bryan et al. 1987). These compounds impose male sexual characters (or imposex) on female N. lapillus. Other stenoglossan gastropods including Nassarius obsoletus Say (Smith, 1981a) and Ocenebra erinacea (L.) (Féral & Gall, 1982) are similarly affected by TBT. The intensity of expression of imposex in N. lapillus can generally be related to the sea water concentration of TBT. The appearance of a small penis and the partial development of a vas deferens first occurs at TBT concentrations below 0.5 ng/1 (as tin), although reproduction appears to be unaffected at this level. At 1–2 ng Sn/1 penis size is markedly increased and in some females proliferation of vas deferens tissue overgrows the genital papilla, thus sterilizing the animal. At slightly higher concentrations virtually all females become sterilized and at around 10 ng Sn/1 oogenesis is suppressed and spermatogenesis initiated (Gibbs, Pascoe & Burt, 1988). Since development is direct and there is no planktonic stage, N. lapillus has a very limited capacity for dispersion: thus the sterilization of females heralds the almost certain decline of so affected populations (Gibbs & Bryan, 1986).

Author(s):  
P. E. Gibbs ◽  
P. L. Pascoe ◽  
G. R. Burt

Imposex, the development of a penis and vas deferens in the female (Smith, 1971) is known to occur in over 30 species of marine gastropods but, to date, in only one species has this syndrome been demonstrated to have a serious deleterious effect. This species is the dog-whelk, Nucella lapillus L. Both field and laboratory observations have provided conclusive evidence that imposex in N. lapillus is initiated by tributyltin (TBT), used as a biocide in antifouling paints, at concentrations in water of less than 1 ng Sn/1. This feature is manifest in the widespread occurrence of imposex even in areas far removed from centres of boating activity (see Bryan et al. 1986). Imposex appears to have little effect on the reproductive biology of N. lapillus until this syndrome is developed to its fullest extent when it sterilises the female because the pallial oviduct becomes occluded by vas deferens tissue thus preventing expulsion of the egg capsules (Gibbs & Bryan, 1986). Laboratory experiments have indicated that this condition, found in females close to harbours and marinas, may prevail after prolonged exposure during the first few years of life to TBT levels as low as 2 ng Sn/1 (Gibbs et al. 1987). Of six organotin compounds tested by Bryan, Gibbs & Burt (1988), tributyltin chloride proved the most effective in promoting imposex in N. lapillus.


Author(s):  
P. E. Gibbs ◽  
G. W. Bryan ◽  
P. L. Pascoe ◽  
G. R. Burt

The term ‘imposex’ was coined by Smith (1971) to describe the superimposition of male characters onto unparasitized and parasitized females of gonochoristic gastropods. In Nassarius obsoletus (Say) the development of imposex results in the female having one or more of the following characters: (1) a penis with a duct leading to (2) a vas deferens which passes back to the ventral channel of the capsule gland and (3) convolution of the normally straight gonadial oviduct (Smith, 1980). Imposex in the similarly gonochoristic Nucella lapillus (L.) was first noted by Blaber (1970) who found females with penis-like outgrowths in Plymouth Sound populations. Subsequent studies (Bryan et al. 1986; Gibbs & Bryan, 1986) have demonstrated that the incidence and intensity of imposex have since increased markedly in the same populations and that the phenomenon is widespread around south-west England.


Author(s):  
P. E. Gibbs ◽  
G. W. Bryan

The development of male characters, notably a penis and a vas deferens, on the female (the phenomenon of ‘imposex’) of the dog-whelk, Nucella lapillus, is described. Three stages are recognized: an ‘early’ stage involving the formation of a vas deferens and a small penis, an ‘intermediate’ stage characterized by the enlargement of the female penis to a size approaching that of the male and a ‘late’ stage during which the female opening (vulva) is occluded by overgrowth of vas deferens tissue. This blockage of the pallial oviduct prevents the release of egg capsules and renders the female sterile. The extent and cause of such reproductive failure is evident from the high incidence of females containing aborted capsules in declining populations close to sources of tributyltin (TBT) contamination. These same populations comprise fewer females than expected and it would appear that the accumulation of aborted capsules within the pallial oviduct eventually causes the premature death of the female.


Author(s):  
D. H. Dalby ◽  
E. B. Cowell ◽  
W. J. Syratt ◽  
J. H. Crothers

A rocky shore exposure scale, intended primarily for use in the Fensfjord area, Western Norway, has been prepared. This scale is developed from an earlier scale devised by Ballantine for Milford Haven, Wales, making use of species abundance curves along the wave exposure gradient. Independent evidence for the validity of the scale is provided by shell shape variation in Nucella lapillus and by the height of the black lichen zone in the supralittoral fringe. The successive steps in the preparation of the scale are outlined, definitions of the exposure grades are given in tabular form for the restricted set of species analysed numerically and descriptions are provided in an extended form to provide a fuller picture for users of the scale. It is believed that the scale will prove applicable to other rocky shores around the North Sea.


Author(s):  
D. F. Jefferies ◽  
C. J. Hewett

INTRODUCTIONThe caesium radionuclides, caesium-137 and caesium-134, are important constituents of aqueous radioactive effluents discharged to the environment of the United Kingdom from fuel re-processing plants and nuclear power stations (Howells, 1966; Mitchell, Harvey & Smith, 1968; Harvey, Baker & Mitchell, 1969). Their accumulation by marine fishes has been the subject of several previous studies, beginning with that of Chipman (1959) who noted that caesium-137 was accumulated in the flesh of the killifish (Fundulus heteroclitus) and that accumulation continued even after a period of 72 days. Similarly, Hiyama & Shimizu (1964) showed that the muscle of the common goby (Acanthobus flaviamus) continued to accumulate caesium-134 from sea water after periods of 30 days. Baptist & Price (1962) have examined the whole body uptake of caesium, by absorption from sea water, in two marine species, the flounder (Paralichthys dentatus) and the Atlantic croaker (Micropogon undulatus), and they also investigated the accumulation, tissue distribution and excretion of caesium-137 in the croaker, the little tuna (Euthynnus alleteratus) and the bluefish (Pomatomus saltatoux), following oral administration of single doses. These authors concluded that the heart, liver and spleen of the croaker absorbed caesium-137 from sea water at a faster rate than the muscle, and that orally administered caesium-137 was rapidly absorbed from the digestive tract. Tissue distributions were similar in the croaker, bluefish and tuna. The retention of caesium-137 in croaker tissue was described as a multiple rate process. In later experiments Hiyama & Shimizu (1969) compared turnover rates in various organs and tissues following uptake from sea water and from single injection experiments, and obtained good agreement between the values from the two methods.


2019 ◽  
Vol 99 (7) ◽  
pp. 1601-1614
Author(s):  
J. M. Ruiz ◽  
B. Carro ◽  
N. Albaina ◽  
L. Couceiro ◽  
M. Quintela ◽  
...  

AbstractWe have monitored tributyltin (TBT) pollution in Galicia (NW Spain) for more than a decade by means of assessing gastropod imposex in populations of Nucella lapillus (N ≥ 34) and Tritia reticulata (N ≥ 18) at regular intervals. Several thousand specimens were processed to obtain their shell height (SH), penis length (PL) and vas deferens sequence (VDS); imposex indices (including the VDS index, VDSI) were subsequently calculated. The regional mean SH of both females and males has not changed significantly in either species throughout the study. This also applies to the mean male PL in N. lapillus, but male T. reticulata penises surprisingly enlarged. On the contrary, the regional mean female PL (MFPL) and all imposex indices significantly decreased in both snails. Results confirm previous conclusions based on the chemical analyses of tissues and partial imposex observations. In addition, the close correlations between MFPL and VDSI show some potential applications to TBT biomonitoring.


Author(s):  
P.E. Gibbs

Laboratory breeding of the dog-whelk, Nucella lapillus, has established that the male-sterilizing Dumpton Syndrome (DS)—underdevelopment, or non-development (aphally), of the penis, incomplete formation (non-closure) of the vas deferens, resulting in a split prostate—can be readily observed in male F1 progeny. Cultivated under high ambient concentrations of the antifouling agent tributyltin (TBT), DS-carrying females can be recognized by their lesser degree of masculinization (imposex): sterilization is thereby avoided. When Dumpton females are crossed, under high ambient TBT, with individuals from a non-DS-affected population (Bude, North Cornwall) DS is absent from both sexes. Crosses of these F1 progeny result in F2 progeny exhibiting the classic DS symptoms in both sexes. A Mendelian mechanism for DS inheritance is suggested by the data.


1982 ◽  
Vol 28 (4) ◽  
pp. 414-424 ◽  
Author(s):  
Richard A. Laddaga ◽  
Robert A. MacLeod

Eighteen gram-negative marine bacteria and two terrestrial species, Escherichia coli and Pseudomonas aeruginosa, were examined for their sensitivity to lysis in distilled water after exposure either to a salt solution containing a sea water concentration of Mg2+ (0.05 M) or to 0.5 M NaCl. A spectrum of lytic susceptibility was observed among the marine bacteria ranging from those organisms which lysed in distilled water after exposure to the Mg2+-containing solution, through organisms which could be sensitized to lysis by washing with the NaCl solution, to organisms which failed to lyse in distilled water even after having been washed with a solution of 0.5 M NaCl. Pseudomonas aeruginosa and E. coli fell within this spectrum, the former being capable of being induced to lyse in distilled water by washing with 0.5 M NaCl, while the latter failed to lyse in distilled water after this treatment. It was thus concluded that no overall distinction could be made between marine and terrestrial bacteria on the basis of the sensitivity of the two groups of organisms to lysis in freshwater.Quite large decreases in optical density and increases in the release of ultraviolet-absorbing material took place when cells preexposed to the Mg2+-containing solution or to 0.5 M NaCl were subsequently suspended in distilled water even though in some cases no loss of cell numbers could be detected. In most cases two to three times as much K+ as Na+ and 1/10 to 1/100 as much Mg2+ was required to prevent these changes. For three of the marine bacteria and P. aeruginosa grown in a terrestrial type medium little difference in the requirements for Na+ and K+ to prevent the optical density changes was noted. For P. aeruginosa grown in a marine type medium, cells required more K+ than Na+ to prevent these changes.


Author(s):  
P. E. Gibbs

Tributyltin (TBT) pollution has exterminated populations of the dog-whelk Nucella lapillus along most of the north Kent coast (Thames Estuary) but the species survives as a small enclave around the North Foreland. Males in this enclave exhibit an unusual defect involving the non-development or partial development of the genital system: about 10% lack penes, or have undersized penes, and their gonoducts (vas deferens and prostate) are incompletely developed; in some cases, spermatogenesis appears to be retarded. Laboratory-bred animals display the same characters. This deficiency (‘Dumpton Syndrome’) is manifest also in the atypical development of male sex organs on the females (‘imposex’) induced by exposure to tributyltin (TBT). The evidence points to Dumpton Syndrome being a genetic disorder which has lessened the sterilizing effect of imposex and thereby has permitted the survival of this isolated enclave in an area of high TBT pollution.


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