Spodoptera Eridania Research Articles

Partial purification and characterization of DNA-dependent RNA polymerases in the southern Armyworm (Spodoptera eridania)

1. Three major forms of DNA-dependent RNA polymerase, tentatively identified as polymerases I, II and III have been solubilized and partially purified by DEAE-Sephadex chromatography from the larval midgut of the southern Armyworm ( Spodoptera eridania, Cramer). 2. The partially purified RNA polymerases exhibited an absolute requirement for all four nucleotide triphosphates and an exogenous template and activity was stimulated by Mn 2+. Greatest activity was observed with poly(dA-sT) as a template. The polymerases were inhibited by actinomycin D with denatured DNA as a template but not with poly(dA-dT). 3. RNA polymerase II was extremely sensitive to inhibition by α-amanitin (I 50 = 10 −9M). 4. RNA polymerase II cochromatographs on DEAE with a third polymerase (tentatively identified as RNA polymerase III) which is highly stimulated by poly(dA-dT) and insensitive to α-amanitin. 5. True RNA polymerase activity could not be measured in fractions prior to DEAE chromatography due to the presence of an endogenous nuclease which interfered with the assay. 6. Unusual ribohomopolymerase activity was observed in the crude nuclear fraction and resulted in the incorporation of any one of the single nucleotide triphosphates. This activity was inhibited by actinomycin D but not by α-amanitin.

Aryl hydrocarbon hydroxylase induction in an insect, spodoptera eridania (cramer), by polychlorinated biphenyls (PCBs)

1. Topical application of PCBs induced aryl hydrocarbon hydroxylase activity in Spodoptera eridania midgut homogenates or microsomes, as measured by increased metabolism of [ 14C]-benzo[a]-pyrene. 2. Low PCB doses produced significant AHH induction. 3. Levels of AHH induction were not proportional to PCB chlorine content. 4. Induction was maximal at 24 hr; the effect persisted for at least 4 days after a single exposure to Aroclor 1254. 5. It appears that AHH induction by PCBs precedes proliferation of smooth endoplasmic reticulum.

The role of DNA-dependent RNA polymerases in microsomal enzyme induction in southern armyworm ( Spodoptera eridania) larvae

RNA polymerase activity in a midgut nuclear fraction from southern armyworm larvae exposed to the microsomal enzyme inducer pentamethylbenzene (PMB, 2000 ppm in diet) was 40% higher than in controls. With the solubilized, partially purified polymerases, the activity of RNA polymerase III increased about 40% in response to the inducing action of PMB; polymerase II activity was only slightly enhanced in induced larvae and no change was observed in the activity of polymerase I. Treatment of larvae with α-amanitin (0.25 μg/larva) or cycloheximide (50 ppm in diet) caused respectively a 60% and 70% reversal of the PMB-induced increase in RNA polymerase activity. Such treatments also cause an essentially complete block of the PMB induction of microsomal N- demethylase and NADPH-cytochrome c reductase. The data are discussed in relation to the involvement of the transcription process in the mechanism of microsomal enzyme induction.

An improved method for the isolation of intact nuclei from southern armyworm ( Spodoptera eridania) larval midgut

Intact nuclei, relatively free of cell debris, were prepared from armyworm midgut tissue by a new, improved procedure involving homogenization in the presence of 0.1% Triton X-100 and 1% polyvinylpyrrolidone followed by sucrose density gradient centrifugation. The nuclear fraction thus prepared was a suitable source for assay of RNA polymerase activity. Polymerase activity was dependent on the presence of all four ribonucleotide triphosphates, was stimulated by Mn 2+ and Mg 2+ and was inhibited by actinomycin D and α-amanitin.

Aryl hydrocarbon hydroxylase in an insect, Spodoptera eridania (cramer)

1. Spodoptera eridania larvae can metabolize the environmental carcinogen benzo[a]pyrene BP) via a microsomal mixed-function oxidase system. Metabolic activation is required for oncogenicity; therefore, BP may be potentially carcinogenic for insects. 2. The enzyme requires NADPH and oxygen and is inhibited by carbon monoxide, indicating cytochrome involvement. Optimal conditions for in vitro BP hydroxylation are defined. 3. Endogenous aryl hydrocarbon hydroxylase inhibitors are located in the gut contents and head capsule. 4. Enzymatic specific activity increases throughout larval development, but declines during the prepupal stage. 5. Spodoptera BP hydroxylase specific activity, while easily demonstrated, is lower than that of several mouse strains.

Cyanogenic glycosides in Lotus corniculatus : Their effect upon growth, energy budget, and nitrogen utilization of the southern armyworm, Spodoptera eridania.

Two genotypes (one cyanogenic and the other acyanogenic) of birds-foot trefoil, Lotus corniculatus L., were used to study the effects of cyanogenic glycosides in leaf tissues upon a polyphagous herbivore, the southern armyworm, Spodoptera eridania Cram. (Lepidoptera). No differences were observed in consumption rate, assimilation efficiency, utilization of plant biomass, or metabolic costs in terms of expended calories between larvae fed acyanogenic or cyanogenic leaves. Similarly no differences were seen in the nitrogen or caloric utilization efficiencies, or in the nitrogen accumulation rate or growth rate of larvae on cyanogenic versus acyanogenic plants. Larval performance and growth on 20-week old plants was generally poorer than on 4 week old plants, however. This was reflected in slower growth, smaller pupal weights, lower nitrogen utilization efficiencies (N.U.E.) and biomass assimilation efficiencies (A.D.) on both the cyanogenic and acyanogenic plants.Although useful as a deterrent to some herbivores, cyanogenesis does not seem to provide an effective defense against this "adapted" herbivore. This study supports current hypotheses of insect/plant coevolution, and suggests that the metabolic costs of processing cyanogenic plant biomass are small in comparison to those imposed by the nutritional status of the plant leaves.

Influence of Stake and Mulch Culture on Lepidopterous Pests of Tomato

Response of various lepidopterous species to staked and artificially mulched culture of tomatoes was evaluated by counting numbers of pests and by examining damage to tomato foliage and fruit. Granulate cutworm, Feltia subterranea (Fab.), numbers and injury to fruit were less in early spring on plants grown on black polyethylene-coated paper mulch. Numbers of granulate cutworms, southern armyworms, Spodoptera eridania (Cramer), and a complex of less abundant noctuid larvae were inhibited by staking. Damage by all species was also reduced in staked plants. Insecticidal sprays applied to staked plants resulted in increased leafmining by tomato pinworms, Keiferia lycopersicella (Walsingham).

Effect of Tomato Cultivars on Insect Damage and Chemical Control

`Pennorange E160A' and `Pearson' tomatoes had fewer fruit damaged by Keiferia lycopersicella (Wals.), the tomato pinworm, and armyworms, primarily Spodoptera eridania (Cramer), the southern armyworm, in 2 tests than on `Walter.' When measured by the number of damaged fruit, the degree of control of the tomato pinworm and southern armyworm with Dipel WP and chlordimeform was significantly affected by tomato cultivar. The number of Liriomyza sativae Blanchard leafmines/10 trifoliates (3 terminal leaflets) was significantly less on UF-763292 (a pubescent mutant breeding line), `Earliana,' `Pennorange E160A' (a cherry tomato), `Pearson,' and `Pritchard' tomato cultivars in 2 tests. Despite significantly more insect damage, `Walter' yielded more than other cultivars, primarily because of less loss from graywall. No large fruited cultivar offered much potential as a replacement for `Walter' in areas where populations of tomato pinworm, armyworms, and leafminers occur annually. `Pennorange E160A' may offer an alternative for home garden use and large, fresh market tomatoes in areas where insects are damaging in most seasons. The multiple resistance of `Pennorange E160A' and `Pearson' to the tomato pinworm, armyworms and the vegetable leafminer may be of benefit in a breeding program.

Herbivore-Plant Interactions: Mixed-Function Oxidases and Secondary Plant Substances

The mixed-function oxidases of a polyphagous insect larva (the southern armyworm, Spodoptera eridania) were found to be induced by a diversity of secondary plant substances. The induction proceeds rapidly and in response to a small quantity of secondary substance. Following induction, the larva is less susceptible to dietary poisoning. It is argued that mixed-function oxidases play a major role in protecting herbivores against chemical stress from secondary plant substances.

Insecticide Solvents: Interference with Insecticidal Action

Several commercial solvent mixtures commonly used as insecticide carriers in spray formulations increase by more than threefold the microsomal N-demethylation of p-chloro N-methylaniline in midgut preparations of southern army-worm (Spodoptera eridania) larvae exposed orally to the test solvents. Under laboratory conditions, the same solvent mixtures exhibit a protective action against the in vivo toxicity of the insecticide carbaryl to the larvae. The data are discussed with respect to possible solvent-insecticide interactions occurring under field conditions and, more broadly, to potential toxicological hazards of these solvents to humans.

Steric factors in the inhibitory interaction of imidazoles with microsomal enzymes

The ability of substituted imidazoles to bind to cytochrome P-450 (type II) and to inhibit microsomal drug-metabolizing enzyme activity is highly dependent on the position of the substituent in the imidazole ring. Compounds containing substituents in the 1-, 4(5)- and 1,5-positions are effective inhibitors of the epoxidation of aldrin in rat liver microsomes and armyworm ( Spodoptera eridania) gut preparations and exhibit low spectral dissociation constants ( K s . In contrast, compounds containing 2- and/or 4-substitutents are essentially inactive as inhibitors and exhibit high K s values (low binding). It appears that both binding and inhibition depend on the accessibility of the non-bonded electrons on the nitrogen atom at position — 3 of the ring.

Structure-activity relationships of 1,2,3-benzothiadiazole insecticide synergists as inhibitors of microsomal oxidation

The activities of 47 substituted 1,2,3-benzothiadiazoles as inhibitors of microsomal epoxidation and/or hydroxylation in enzyme preparations from rat liver or armyworm ( Spodoptera eridania) gut have been evaluated. Many were found to be effective inhibitors of microsomal oxidation, the most active being the 6-butyl and 6-propoxy derivatives with I 50 values of 4.9 × 10 −7 and 7.0 × 10 −7 M, respectively, for the epoxidation reaction. Regression analyses have established that activity of the 5-, 6-, and 5,6-substituted compounds can be satisfactorily described in equations in terms of π 2, π, and σ whereas that of the 4-substituted derivatives depends on π and the steric parameter E 8.

Rosette formation by insect macrophages inhibition by cytochalasin B

Macrophages from the insect Spodoptera eridania possess membrane receptors for unmodified avian and mammalian erythrocytes, with which they form spontaneous rosettes. Rosette formation occurs in the absence of serum proteins and divalent cations. Individual macrophages bear receptors for several types of red cells. The level of naturally-occurring hemagglutinins against a particular test erythrocyte is not correlated with macrophage reactivity against that red cell. In contrast with mammalian macrophages, neuraminidase treatment of either hemocytes or erythrocytes does not cause a marked enhancement of binding. Pretreatment of macrophages or erythrocytes with cytochalasin B causes reversible inhibition of resetting probably by interfering with normal microfilament function, suggesting that optimal binding occurs when membranes are functioning normally on both macrophages and red cells. Colchicine and vinblastine do not influence resetting; therefore, microtubules are probably not involved in erythrocyte binding.

Relationship Between Formamidine Structure and Insecticidal, Miticidal, and Ovicidal Activity

The insecticidal, miticidal, and ovicidal activities of 5 formamidines, including chlordimeform, were examined in laboratory studies against eggs and adults of the twospotted spider mite, Tetranychus urticae Koch, carmine spider mite, T. cinnabarinus (Boisduval), and citrus red mite, Panonychus citri (McGregor), mobile forms of the green peach aphid, Myzus persicae (Sulzer), and eggs and early-stage larvae of the southern armyworm, Spodoptera eridania (Cramer), cabbage looper, Trichoplusia ni (Hubner), bollworm, Heliothis zea (Boddie), and tobacco budworm, H. virescens (F.). In general, excellent ovicidal and larvicidal activity was associated with N′-(2-methyl-4-chlorophenyl) substituted formamidines while the N′-(2,4-dimethylphenyl) analogs were significantly more toxic to adult miles and aphids. In response to treatment by the formamidines, adult mites displayed distinctive behavioral patterns: one, “walkoff” was associated with the nature of the formamidine, the other, “spindown” with the arylthio substituent present on 2 of the compounds. Chemical modifications of insecticidally active parent N-aryl-N-methylformamidines have resulted in the production of more toxic compounds.

Microsomal hydroxylation of aniline in the southern armyworm, Spodoptera eridania

Microsomal hydroxylation of aniline in midguts of the southern armyworm, Spodoptera eridania, was found to differ in its requirements for optimal in vitro activity from those of armyworm and rat liver p- chloro N- methylaniline N- demethylase and rat liver aniline hydroxylase. Apparent K m values for armyworm aniline hydroxylase were substantially higher than those for rat liver aniline hydroxylase and the N- demethylase enzymes. The armyworm aniline hydroxylase was inhibited by several mixed-function oxidase inhibitors as well as by aldrin and nicotine and was highly inducible by pentamethylbenzene and phenobarbital.

Properties of 5-aminolaevulinate synthetase and its relationship to microsomal mixed-function oxidation in the southern armyworm (Spodoptera eridania)

1. Activity of 5-aminolaevulinate synthetase was measured in the midgut and other tissues of the last larval instar of the southern armyworm (Spodoptera eridania Cramer, formerly Prodenia eridania Cramer). 2. Optimum conditions for measuring the activity were established with respect to all variables involved and considerable differences from those reported for mammalian enzyme preparations were found. 3. Maximum activity (20 nmol/h per mg of protein) occurs 18-24 h after the fifth moult and thereafter decreases to trace amounts as the larvae age and approach pupation. 4. Synthetase activity was rapidly induced by oral administration (in the diet) of pentamethylbenzene, phenobarbital, diethyl 1,4-dihydro-2,4,6-trimethylpyridine-3, 5-dicarboxylate, and 2-allyl-2-isopropylacetamide. 5. Puromycin inhibited the induction of synthetase by pentamethylbenzene. 6. Induction of 5-aminolaevulinate synthetase correlated well with the induction of microsomal N-demethylation of p-chloro-N-methylaniline, except for phenobarbital, which induced the microsomal oxidase relatively more than the synthetase.

The cervical and thoracic musculature of Lepidoptera

Summary The cervicothoracic musculature of Manduca sexta (Johannson) and of Spodoptera eridania (Cramer) is described and figured. This brings to 12 the number of lepidopterous families that have been so treated, and thus places the Lepidoptera in an exceptionally favourable position for analysis of their general muscular complement. The description of muscles for Manduca and Spodoptera is given in a form that provides a comprehensive classification of the cervicothoracic muscles of this order.

An Attractant for Males of Spodoptera dolichos (Lepidoptera: Noctuidae)

Cis-9,trans-12-tetradecadien-1-ol acetate (hereafter referred to as Cis-9,tratus-l2-tda) was identified as the sex pheromone of the Indian meal moth, Plodia interpunctella (Hübner) (Kuwahara et al. 1971, Brady et al. 1971), and a component of the sex pheromone of the southern armyworm, Spodoptera eridania (Cramer) (Jacobson et al. 1970). Moreover, Brady and Ganyard (1972) isolated Cis-9,trans-12-tda from females of the beet armyworm, Spodoptera exigua (Hübner). The Indian meal moth is in the superfamily Pyraloidea, and the southern and beet armyworms belong to Noctuoidea. In view of this apparent wide range of attractancy demonstrated by Cis-9,trans-12-tda, a study was conducted at Hastings, Fla., during spring and early summer of 1972 to determine whether this compound possibly might be attractive to still other insect species. The present paper reports the results of studies made to determine the attractiveness of Cis-9,trans-12-tda to males of the armyworm Spodoptera dolichos (F.), and its effect on the response of male soybean loopers, Pseudoplusia includens (Walker), to synthesized Cis-7-dodecenl-ol acetate (hereafter referred to as cis-7-dda), the sex pheromone produced by the female soybean looper (Tumlinson et al. 1972).

Toxicity of certain insecticide standards against the southern armyworm.

Thirty-one insecticide standards in commercial use were tested topically against 4th instars of Spodoptera eridania (Cramer). The toxicity trend among organophosphorus compounds was phosphates. > phosphorothionates > phosphorothiolates > phosphorodithioates. However, topical LD50 values for monocrotophos and chlorpyrifos were 93.52 and 5.68 µg/g, respectively. The same 2 compounds have LC50 values of 11.3 and 11.0 ppm when tested, using the leaf-spray method. Monocrotophos apparently penetrates the cuticle more slowly than does chlorpyrifos.

Antimetabolite Effects on Larval Feeding of Spodoptera eridania12

Tomato leaves soaked in solutions of 7 antimetabolite compounds were offered to larvae of Spodoptera eridania (Cramer) to determine whether these materials affect larval feeding and development. Thiouracil-treated leaves were not appreciably consumed by larvae, weight gain was poor, and only 1 adult was produced from 54 larvae fed this diet. Thiouracil apparently acts as a deterrent to larval feeding.