Correlation Between the Possession of a Chitinous Cuticle and Sensitivity to DDT

Richards, A. Glenn; Cutkomp, L. K.

doi:10.2307/1538214

Cited by 62 publications

(12 citation statements)

References 18 publications

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“…The presence of a chitinous cuticle in both terrestrial and aquatic organisms was suggested to impart sensitivity to DDT because the cuticle acts as site of transport for this nonpolar hydrophobic compound [31] Further research demonstrated that the chitin cuticle was a major site for insecticide accumulation in insects [321 If passive diffusion of hydrophobic contaminants across the integument contributes significantly to the total flux of contaminants into the animal, and if the cuticle does not pass oxygen, then the model of K,, equal to K-O2 is no longer appropriate, even if the efficiency of transfer is the same over the respiratory portion of the organism's surface Instead, the model for contaminant accumulation should indude some function of body size to incorporate the potential passage of the contaminant across the chitin cuticle From the regres-ions, the surface area-to-volume ratio yields the most significant regressions among the comparisons This result mdicates that the total surface area is important for the uptake of these contaminants Based on the Gobas et a1 model [33] for the range of compounds examned, membrane permeation control is suggested as the basic mechanism governing the accumulation of the compounds, because the rate coefficients generally increase with increasing contaminant lipophilicity The model employs several potential rate-determning steps to describe the accumulation of contammants First, an aqueous diffusion layer must be crossed Second, a transfer across the membrane barrier may act as the rate-determining step Third, but not considered in the Gobas model, distribution of contaminants away from the membrane barrier to maintain a chemical activity gradient may also be rate-determining This third potential rate-determining step was important for the accumulation of insecticides by various insects [32] For BaP and HCBP, the clearance was proportional to the surface area-to-volume ratio of the organisms This relationship suggests that the distribution away from the membrane could be rate-hmtmg because the distribution will slow as the volume of the organism increases BaP and HCBP are very hydrophobic compounds, once they are in the membrane, they are likely to resist dissolution into the body water for distribution to the rest of the organism. Thus, the rate-determining step for contaminant distribution likely includes the desorption rate from the membrane.…”

Section: Contaminant Clearancementioning

confidence: 99%

ROLE OF RESPIRATION IN THE ACCUMULATION OF ORGANIC XENOBIOTICS BY THE AMPHIPOD DIPOREIA sp.

Landrum¹,

Stubblefield²

1991

Environ Toxicol Chem

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Accumulation of hydrophobic organic xenobiotics is thought to occur by passive diffusion across the respiratory membrane of aquatic organisms. This route has been confirmed with fish. However, aquatic invertebrates tend to remove organic xenobiotics from water much more efficiently than oxygen, based on the relative uptake clearances. Uptake clearance is the rate coefficient that describes the volume of water stripped of analyte per g of organism per h. For the amphipod Diporeia sp., formerly classified as Pontoporeia hoyi, ratios of the contaminant uptake clearances to oxygen clearance were essentially constant at 3.9 ± 0.4 (X + SE) for benzo[α]pyrene (BaP), 3.8 ± 0.3 for hexachlorobiphenyl (HCBP), and 4.2 ± 0.6 for phenanthrene (Phe). Therefore, based on the membrane transport efficiencies of nonpolar xenobiotics (60–80%) and oxygen (approximately 63%) in fish, and the uptake clearance for organic xenobiotics by Diporeia sp., either xenobiotics are accumulated through routes other than across the respiratory membrane or the accumulation efficiency of oxygen from water is much lower in amphipods than it is in fish. The variability in the uptake clearance for both BaP and HCBP was best described by regressions with the surface area‐to‐volume ratio, whereas the uptake clearance for the more hydrophilic Phe was best described by a total surface area relationship.

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Section: Contaminant Clearancementioning

confidence: 99%

ROLE OF RESPIRATION IN THE ACCUMULATION OF ORGANIC XENOBIOTICS BY THE AMPHIPOD DIPOREIA sp.

Landrum¹,

Stubblefield²

1991

Environ Toxicol Chem

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“…Productivity of T. confusum "Chicago standard" was superior to that of T. castaneum "Brazil cl" when stressed by DDT; whereas, x-radiation caused the reverse species response (Erdman unpublished). The detoxication mechanisms of a species or a strain might be explained on a physiological basis (Grosswald 1934, Welsh andGordon 1947) ; nevertheless, one should not overlook the possibility of morphological (Castle 1936, Richards andCutkomp 1946) or behavioral adaptations (Martinez-Palacios and de Zulueta 1964). The association of a genetically controlled body color difference with insecticide resistance between "sooty" (black) and "Brazil cl" (wild type) will be explored further.…”

Section: Discussionmentioning

confidence: 99%

Modification of Fitness in Species and Strains of Flour Beetles due to X‐Ray and DDT

Erdman¹

1966

Ecology

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Insecticides and ionizing radiations can induce population changes which under selection are beneficial or harmful. Such changes are known in some cases to have a genetic basis. Studies were designed to determine the early effects of DDT and x-radiation, singly and in combination, on mortality and productivity of flour beetle species and strains ( Tribolium confusum Duval "Chicago standard" and T. castaneum Herbst "Brazil cl" and "Sooty"). Five replicate populations each containing ten pairs of virgin beetles x-rayed with 0, I, 2 or 4 kR of x-rays (250 kvp, 30 rna, 0.25 mm Cu + 1.0 mm AI filtration, 0.86 mm Cu HVL and 2.5 inches between target and subjects produced I kR/min) were cultured under standard conditions in food containing 0, 5, IO, 20 or 50 ppm DDT. Every two weeks for six weeks parental mortality was recorded and living adults were placed on fresh comparable food. The old food was reincubated and F 1 adult biomass and numbers were the measures of productivity.Parental mortality was I) unaffected by x-rays, 2) increased for "Brazil cl" at 50 ppm DDT, and 3) greater for females than males but unrelated to radiation or insecticide.Productivity measurements decreased with increasing x-ray or DDT. Productivity of T. confusum was, in general, more radiation-sensitive than that of T. castaneum strains, whereas, both T. castaneum strains were more DDT -sensitive than was T. confusum. Radiation of 4 kR was almost sterilizing to T. confusum; of T. castaneum strain "Brazil cl" left no F 1 at 50 ppm DDT.Proportions of Iethals due to x-ray or DDT were considered genetic dominants and used to quantify the relationship between radiation and insecticide in combination. Observed lethality simulated that expected for genetic dominant lethal effects when "Chicago standard" and "Brazil cl" were stressed with x-ray plus DDT. In "sooty," observed lethality was consistently lower than that predicted on the assumption of dominant lethal effects; i.e., productivity was less adversely affected when both stresses were applied than that expected by multiplying the effects of singly stressed populations.Within a species "sooty" populations showed more lethality due to x-rays than did "Brazil cl" populations; DDT had the opposite effect.

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“…It is not clear how this comes about with pure poisons which are insoluble in water. Insecticides may be more soluble in insect blood than in water itself (Richards & Cutkomp, 1946); some further remarks about this are given in 92C.…”

Section: B Penetration and Particle Sizementioning

confidence: 99%

“…If a poison is injected into the body cavity of an insect, it will come into contact with the blood at once and will diffuse through or be carried by it to the site of action. The solubilities of rotenone and D D T in water are extremely low (Jones & Love, 1937;Richards & Cutkomp, 1946), and if the blood were simply an aqueous solution, there would be no reason to believe that their solubilities in it differed by much. They would both be low, and one might expect that in both cases the smallest particles would be the most toxic, or would act the most quickly.…”

Section: Transport Of Poison By Blood After Injection (See Part 111)mentioning

confidence: 99%

Particle Size of Insecticidal Suspensions and Their Contact Toxicity Iv. Mechanisms of Action of Different‐sized Particles

McIntosh

1951

Annals of Applied Biology

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Two earlier papers showed that in tests of suspensions by dipping, large crystals of D D T could kill grain beetles just as efficiently as colloidal DDT. But with rotenone, colloidal particles were far more toxic than large crystals; this difference was partly in their speeds of action. A third paper showed that in contact action the relative toxicity of small particles is increased by cooling the beetles after treatment. In tests by injection into milkweed bugs, particle size seemed to have no effect on toxicity of rotenone and D D T suspensions if the bugs were kept warm after treatment. In cool bugs, colloid acted more quickly than crystals, but the kills from the two types finally became the same. T h e time for this to come about was less for D D T than for rotenone and less still for D F D T , an analogue of DDT.An explanation of these results is now given. In the action of contact poisons, attention is given to the waxy layer on the outside of the cuticle. Contact poisons must first of all dissolve in this wax layer, and it is suggested that the difference in action between rotenone and D D T is due to a difference in their solubilities in wax.Small particles will always have the advantages, over large, of greater surface area and greater ability to enter openings in the body. With Oryzaephilus surinamensis, a main route of entry by rotenone into the body is possibly through the spiracles, and this may be why colloidal rotenone is so much more toxic than rotenone crystals. T h e solubility of rotenone in wax is thought to be small and if this is so, it will be easy to saturate the wax and the higher solubility of very small particles of rotenone will be of importance. The behaviour of rotenone particles of different sizes is therefore understandable.Entry through the body openings is evidently unimportant for DDT, because large crystals kill as quickly as small ones. Penetration must be through the general cuticle. It is suggested that the solubility of D D T in wax is very high, compared with rotenone ; the wax will not be easily saturated by D D T and small particles will not have the advantage of higher solubility, which is only helpful if saturation is reached.It is shown theoretically that if solubility (in wax) does decide the relative behaviour of different-sized poison particles, then colloidal poison should be more toxic, relative to crystalline poison, if the insects are kept cool after treatment than if they are kept warm.The following explanation is offered for the injection results. The blood of milkweed bugs contains free droplets of oil, and these are mainly responsible for carrying poison from injected crystals to the site of action. Colloidal poison probably diffuses there directly, and more quickly, in the aqueous phase of the blood. The difference in speeds of action of colloidal and crystalline poison will depend on the ratio of dose to solubility in oil. If this is large, saturation of the blood is easy, and * Present address. The author was seconded to New Haven during 1950.

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Correlation Between the Possession of a Chitinous Cuticle and Sensitivity to DDT

Cited by 62 publications

References 18 publications

ROLE OF RESPIRATION IN THE ACCUMULATION OF ORGANIC XENOBIOTICS BY THE AMPHIPOD DIPOREIA sp.

ROLE OF RESPIRATION IN THE ACCUMULATION OF ORGANIC XENOBIOTICS BY THE AMPHIPOD DIPOREIA sp.

Modification of Fitness in Species and Strains of Flour Beetles due to X‐Ray and DDT

Particle Size of Insecticidal Suspensions and Their Contact Toxicity Iv. Mechanisms of Action of Different‐sized Particles

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