Observations on lesser-known flatworms: Udonella

Udonella caligorum is acknowledged as a monogenean by some (Baer & Euzet, 1961; Yamaguti, 1963), but not by others (Ivanov, 1952; Bychowsky, 1957). It also has many similarities to Temnocephala, a rhabdocoel turbellarian. Light and electron microscope studies showed that the posterior sucker is glandular and that neither the adult nor eggs possess hooks; the head-gland secretion is eosinophilic and granular, and the tegument composed primarily of secretory granules and mitochondria. Ten pair of cells appearing to be paranephrocytes are present. Udonella larvae were shown to be larger than the host copepod nauplii, so transmission of worms between hosts must occur either during host mating, casual contact of hosts, or through free worms on the surface of the fish which the copepod infests.     

The effect of development of Taenia hydatigena larvae in the peritoneal cavity of dogs on resistance to a challenge infection with Echinococcus granulosus

Activated oncospheres of T. hydatigena within filtration membrane diffusion chambers implanted intraperitoneally into dogs developed into larvae 3 mm in dia possessing a scolex anlage without hooks. Exogenous antigens released by developing T. hydatigena larvae failed to stimulate any measurable resistance in the dogs to challenge infection with E. granulosus protoscolices.     

Development of the braconid wasp Cotesia flavipes in two Crambids, Diatraea saccharalis and Eoreuma loftini: Evidence of host developmental disruption

Cotesia flavipes is an important gregarious larval endoparasitoid of several crambid stem borers, including Diatraea saccharalis. The suitability of two crambid species, Eoreuma loftini and D. saccharalis, pests of sugarcane and rice in Texas, for C. flavipes development was tested. The effect of parasitization by C. flavipes on encapsulation response was assessed in vivo in both D. saccharalis and E. loftini. The results indicated that the parasitoid developed and emerged successfully in D. saccharalis larvae. Although E. loftini larvae were readily parasitized by C. flavipes parasitoids, no wasp larvae hatched from the eggs in this host because eggs were encapsulated by the host's hemocytes. The developmental fate of the E. loftini larvae with encapsulated parasitoids was variable. Most died as abnormal fifth instars or as post-wandering prepupae, while a few developed normally to the pupal stage. In vivo experiments, there was a significant reduction in the percent of beads encapsulated in parasitized larvae in both hosts. However, the percent of beads showing melanization decreased significantly in parasitized D. saccharalis larvae but did not differ significantly in parasitized or unparasitized E. loftini larvae. Our results showed that D. saccharalis is a suitable host for C. flavipes whereas E. loftini is an unsuitable host. This study indicated that lepidopteran stem borers that are taxonomically, behaviorally, and ecologically very similar can differ in their ability to encapsulate a parasitoid species.     

Echinococcus granulosus: Hook-muscle systems and cellular organisation of infective oncospheres

The morphology of the oncospheres of Echinococcus granulosus has been reconstructed from thin and semi-thin serial sections. Four major types of oncospheral cells have been identified. These consist of: (1) a bi-nucleate medullary center, (2) glandular regions (eight nuclei) subdivided into three types of oncospheral glands, (3) ten germinative cells, and (4) 34 muscle cells, of which 16 are somatic and 18 are hook muscle cells. The hook muscle cells of each hook are organized functionally into the three following systems: (1) the protraction system, for hook extension, (2) the abduction system for drawing the hooks together toward the median plane of bilateral symmetry, and (3) the retraction system for pulling the hooks back into the body. The interconnections observed between different muscle fibers provide a structural basis for coordinated hook action.     

Uptake of homologous haemolymph protein by salivary glands of Chironomus thummi

Radioisotopically labelled homologous protein fractions were injected into the haemolymph of Chironomus larvae. Among four different protein fractions, fraction II appears to enter the salivary gland and accumulates in the glandular lumen. Lack of blood pigmentation in the gland and secretion lumen indicates that the haemoglobin is probably not secreted, but a portion of the haemoglobin molecule or a fraction co-precipitating with haemoglobin in fraction II is being transported by the gland. Since only a portion of fraction II is taken up and secreted, the specificity of the process suggests to us a molecular basis for the activity which must ultimately be reflected in the genes of the transporting tissue.     

松果梢斑螟对虫害诱导寄主防御的抑制作用

以松果梢斑螟（Dioryctria pryeri）-油松（Pinus tabuleaformis）（2年生球果和新梢）为研究对象,探讨梢斑螟幼虫对油松球果小卷蛾（Gravitarmata margarotana）先期虫害诱导寄主防御的抑制作用,以及虫害诱导的负防御机制。结果表明,双萜松脂酸作为油松球果和新梢的主要组成和诱导性防御物质,梢斑螟虫害后球果双萜松脂酸极显著增加,10 d后降低到正常水平;而新梢虫害后,松脂酸显著增加,后随新梢基础含量而增加,10 d后虫害新梢松脂酸显著高于球果。梢斑螟幼虫以小卷蛾虫害球果、健康球果和新梢等部位为食料,均为梢斑螟5龄幼虫下唇腺葡萄糖氧化酶（Glucose oxidase,GOX）活性最高,极显著高于4龄和3龄幼虫;且同一龄期,小卷蛾虫害球果中的梢斑螟幼虫GOX活性最高,显著高于新梢和健康球果中幼虫酶活性。研究发现,虫害后萜类防御物质随幼虫GOX活性升高呈下降趋势。梢斑螟幼虫RNA和P含量比较发现,取食小卷蛾虫害球果、健康球果和新梢3种食料,均为梢斑螟3龄幼虫最高,5龄幼虫最小,差异极显著;但同一龄期,3种食料发育的幼虫,其RNA和P含量间无显著差异。这些结果说明,小卷蛾幼虫的先期危害,诱导了寄主防御,但后来的梢斑螟幼虫通过下唇腺GOX抑制了寄主的诱导防御,使其生长率与健康球果和新梢中的幼虫基本一致。     

On the structure of the Z pseudo-organ in Xiphinema diversicaudatum

The structure of the Z pseudo-organ in Xiphinema diversicaudatum consists of a muscular mass of about 80 cells arranged in rings of four cells each. These cells have peripheral nuclei and are connected with a glandular monolayered epithelium, which lines the lumen of the Z pseudo-organ. Globular bodies originate from the membranes of the epithelial tissue. They consist of a series of closed vesicles containing secretions, and of tubules through which the secretions flow into the lumen. The globular bodies have a helicoidal distribution within the lumen of the Z pseudo-organ which presumably slows the passage of the egg. Enzymatic digestion, in vivo, indicates that the secretion consists of acid and basic proteins involved in egg shell formation.     

Combined effect of salinity and temperature on Spirorbis spirorbis L. and Circeus spirillum L. larvae from the White Sea

The combined effect of salinity and temperature on Spirorbis spirorbis L. and Circeus spirillum L. larvae from the White Sea was studied in the laboratory experiments. In the White Sea, S. spirorbis is distributed through the depth of 1-20 m and is affected by all varieties of fluctuations in salinity and temperature. C. spirillum lives in more wide range of depths 1-55 m and is more stenohaline. S. spirorbis larvae are sufficiently more resistant to the low salinity (10‰) than C. spirillum larvae. Both species are stenothermic. Highest survivorship of S. spirorbis larvae was marked under 5 °C in all experimental salinities. Under temperature treatments of 10-15 °C, the larval survivorship was sufficiently restricted in all salinities. Highest survivorship of C. spirillum larvae was also marked under 5 °C but in more narrow salinity range.The number of larvae undergoing metamorphosis in both species was very low, only about 10% of the total number. Highest number of successful attachments in both species was marked in high salinities (25-30‰) and does not exceed 25% of survivors. Experimental data suggests that salinity and temperature affect directly general survivorship of the larvae and secondary-attachment and metamorphosis processes.     

A laboratory evaluation of the pathogenicity of Bacillus popilliae var. rhopaea, the agent of milky disease in Rhopaea verreauxi (Coleoptera: Scarabaeidae)

Two methods of infection, i.e., feeding known numbers of spores and rearing larvae in contaminated peat, were used to bioassay the susceptibility of Rhopaea verreauxi to Bacillus popilliae var. rhopaea at 23°C. The susceptibility of the three larval instars was similar as measured by the ID₅₀ and IC₅₀ values. However, within an instar, newly molted larvae were less susceptible than mature larvae when infected by the contaminated peat method. It is suggested that this was due to reduced food intake. The range of ID₅₀ values for all bioassays with R. verreauxi larvae were 1.1 × 10⁷ to 4.0 × 10⁷ spores per larva, and IC₅₀ values were 3.4 × 10⁶ to 5.0 × 10⁷ spores per g of contaminated peat. The slope of the probit line was always low (0.6 to 1.8) except for young first-instar larvae infected by contaminated peat when the slope was 4.0. Disease per se did not affect food intake, though intake was reduced at high doses of contaminated peat. Young larvae often died without developing symptoms but, with increasing age, infected larvae were more likely to develop symptoms. Bioassays with Othnonius batesi and Rhopaea morbillosa indicated a much lower susceptibility per os than for R. verreauxi. It is concluded that the potential for using B. popilliae var. rhopaea to control R. verreauxi is high, but the bacillus is unlikely to be of value in control of O. batesi or R. morbillosa.     

Interorder transfer of mycoplasma-like microorganisms between Drosophila paulistorum and Ephestia kuehniella: Tissues,dosages, and effects

Testis and head extracts of sterile male intersemispecific hybrid Drosophila paulistorum are pathogenic when injected into Ephestia kuehniella larvae. The time and frequency of death of the recipients is a function of the extract concentration. Extracts of Ephestia recipients are pathogenic and will kill E. kuehniella larvae and D. paulistorum adults. Larval Drosophila recipients of these extracts survive through pupation. A majority of these recipients fail to eclose. Those animals which do survive to the adult stage and which are fertile demonstrate the same pattern of sterility among their progeny as is found in D. paulistorum hybrids and recipients of D. paulistorum extracts. The results indicate that the pathogenicity of the extracts is due to the mycoplasma-like microorganisms which are responsible for the male intersemispecific hybrid sterility in D. paulistorum. The mycoplasma-like microorganisms grow rapidly in E. kuehniella hosts, with a division time of approximately 1.8 hr, and they retain their host specificity for the semispecies of D. paulistorum.     

O-Methyletransferases endoplasmiques de Populus nigra

O-Methyltransferases catalysing the methylation of caffeic acid to ferulic acid, isoferulic acid and dimethylcaffeic acid were extracted from the endoplasmic reticulum of Populus glandular tissue. The significance of methoxylated cinnamic acids in secreted flavonoid biosynthesis is discussed.     

Two new subspecies of Bacillus thuringiensis isolated in Japan: Bacillus thuringiensis subsp. kumamotoensis (serotype 18) and Bacillus thuringiensis subsp. tochigiensis (serotype 19)

Bacteriological and serological characteristics of three Bacillus thuringiensis isolates obtained in Japan were investigated. They formed typical rhomboidal parasporal inclusions but flagellar (H) antigens of these isolates were different from those of the known 17 H serotypes of B. thuringiensis. The three isolates were divided into two new serotypes (serotypes 18 and 19). The serotype 18 isolate (3–71) produced thermostable exotoxin and the inclusions of this isolate were toxic to larvae of the silkworm, Bombyx mori, but nontoxic to larvae of the mosquito, Aedes aegypti. The other isolate (119-72) belonging to serotype 18 produced inclusions nontoxic to larvae of B. mori and A. aegypti and did not produce thermostable exotoxin. However, other bacteriological properties of the isolate 119-72 were similar to those of the isolate 3–71. The serotype 19 isolate (117-72) produced inclusions nontoxic to larvae of B. mori and A. aegypti and did not produce thermostable exotoxin. Acid production from saccharose and the production of brownish purple pigment were observed in the two serotype 18 isolates, while neither of them was observed in the serotype 19 isolate. In other 29 biochemical properties tested, there was no difference among the three isolates. Based on these characteristics, the following two subspecies names are proposed: Bacillus thuringiensis subsp. kumamotoensis (serotype 18) for the type strain 3–71 and Bacillus thuringiensis subsp. tochigiensis (serotype 19) for the type strain 117-72.     

Larvicidal activity of Bacillus thuringiensis subsp. israelensis, serovar H14 in Aedes aegypti: Histopathological studies

Bacillus thuringiensis subsp. israelensis, serovar H14, when applied as a primary commercial powder, caused the rapid death of Aedes aegypti larvae. Mortality started 6 min after application of 4 μg/ml of the pathogen and reached a maximum 27 min later. When the LC₅₀ (10 ng/ml) was applied, mortality began after 37 min and reached a maximum 120 min later. Histopathological changes in B. thuringiensis israelensis-treated larvae could be observed only in the midgut and caeca. In B. thuringiensis israelensis-treated “dead larvae”, the epithelial layer is disorganized, most of the cells have disappeared and the peritrophic membrane is broken. The epithelium in the B. thuringiensis israelensis-treated “living larvae” still maintains its monolayer structure, but with marked cellular hypertrophy and vacuolized cytoplasm. Also, the “brush border” is thinner and disrupted. Based on the fact that mortality of A. aegypti is a quick process, and because the histopathological changes caused by B. thuringiensis israelensis are similar to those found in lepidopterous larvae treated with pure δ-endotoxin of other B. thuringiensis variants, it is suggested that larvicidal activity of B. thuringiensis israelensis in A. aegypti is due to its δ-endotoxin.     

The initiation of coiling behaviour prior to desiccation in the infective larvae of Trichostrongylus colubriformis

Wharton D.A.1981. The initiation of coiling behaviour prior to desiccation in the infective larvae of Trichostrongylus colubriformis. International Journal for Parasitology11: 353–357. Infective larvae of Trichostrongylus colubriformis coil during the evaporation of water films. Decreasing the depth of the liquid film does not initiate coiling but enclosure in capillary tubes of similar diameter to the track width of actively swimming or crawling larvae results in a marked stimulation of coiling behaviour. It is suggested that larvae coil in response to the progressive restriction of lateral movement in an evaporating water film. The behavioural flexibility of the infective larvae of T. colubriformis maximizes both their survival and their chances of infection.     

The comparative susceptibilities of Pieris brassicae and P. rapae to a granulosis virus from P. brassicae

A comparison was made of the dosage-mortality responses of larvae of Pieris brassicae and P. rapae to infection by P. brassicae granulosis virus (GV). Bioassays with first, second, third, and fourth-instar larvae of both species revealed a marked difference in susceptibility between instars and between species. Median lethal dosages (LD₅₀s) for P. rapae larvae ranged from five capsules for the first instar to 662 capsules for the fourth instar. With P. brassicae, this range extended from 66 capsules to 2.3 × 10⁷ capsules. The time-mortality responses of the two species were similar when fed virus dosages equivalent to an LD₉₀. Median lethal times (LT₅₀s) ranged from 5 days for first-instar larvae to 7–8 days for fourth-instar larvae. A comparison between a long-established laboratory stock of P. brassicae and a stock recently acquired from the field showed no significant difference in their susceptibility to GV. The implications of the pronounced species differences in susceptibility to GV infection are discussed in relation to the potential field control of P. rapae and P. brassicae.     

Anisakis spp. larvae in three mesopelagic and bathypelagic fish species of the central Mediterranean Sea

In this work 437 fish samples of species belonging to the families Myctophidae (Electrona risso and Diaphus metopoclampus) and Phosichthyidae (Vinciguerria attenuata) were examined for the presence of Anisakidae larvae. The study was performed with fishes in the central Mediterranean Sea, particularly in the Strait of Sicily and in the Strait of Messina. The visual inspection and chloro-peptic analysis revealed the presence of nematode parasites with prevalence values between 2.9% in Electrona risso samples and 5.4% in Vinciguerria attenuata samples. A positive correlation was found between standard length (SL) and prevalence of infestation in D. metopoclampus samples (p < 0.05). The larvae examined were morphologically ascribed, at genus level, to Anisakis morphotypes I and II and molecularly identified as Anisakis pegreffii, Anisakis ziphidarum and Anisakis physeteris, in 67%, 9% and 24% of the fish samples examined. Overall, A. pegreffii and A. ziphidarum larvae were isolated in 14 and 2 specimens of D. metopoclampus respectively, A. physeteris larvae were found in 3 E. risso and 2 V. attenuata. A positive correlation was found between standard length and prevalence of infestation in D. metopoclampus samples (p < 0.05). First information is provided on the presence of Anisakis spp. larvae of the myctophid fish species E. risso, D. metopoclampus and V. attenuata from the Central Mediterranean. It is also confirmed the role of lanternfishes (Myctophidae) as paratenic hosts for Anisakis spp.     

Local immune response against larvae of Rhipicephalus (Boophilus) microplus in Bos taurus indicus and Bos taurus taurus cattle

Bos taurus indicus cattle are less susceptible to infestation with Rhipicephalus (Boophilus) microplus than Bos taurus taurus cattle but the immunological basis of this difference is not understood. We compared the dynamics of leukocyte infiltrations (T cell subsets, B cells, major histocompatibility complex (MHC) class II-expressing cells, granulocytes) in the skin near the mouthparts of larvae of R. microplus in B. t. indicus and B. t. taurus cattle. Previously naïve cattle were infested with 50,000 larvae (B. t. indicus) or 10,000 larvae (B. t. taurus) weekly for 6 weeks. One week after the last infestation all of the animals were infested with 20,000 larvae of R. microplus. Skin punch biopsies were taken from all animals on the day before the primary infestation and from sites of larval attachment on the day after the first, second, fourth and final infestations. Infiltrations with CD3⁺, CD4⁺, CD8⁺ and γδ T cells followed the same pattern in both breeds, showing relatively little change during the first four weekly infestations, followed by substantial increases at 7 weeks post-primary infestation. There was a tendency for more of all cell types except granulocytes to be observed in the skin of B. t. indicus cattle but the differences between the two breeds were consistently significant only for γδ T cells. Granulocyte infiltrations increased more rapidly from the day after infestation and were higher in B. t. taurus cattle than in B. t. indicus. Granulocytes and MHC class II-expressing cells infiltrated the areas closest to the mouthparts of larvae. A large volume of granulocyte antigens was seen in the gut of attached, feeding larvae.     

In vivo inhibition of Helicoverpa armigera gut pro-proteinase activation by non-host plant protease inhibitors

We evaluated 22 different host and non-host plant protease inhibitors (PIs) for in vivo inhibition of Helicoverpa armigera gut pro- and proteinases, and their biological activity against the pod borer, H. armigera, the most important pest of agriculture and horticultural crops worldwide. In vitro activation of H. armigera gut pro-proteinases (HaGPPs) in larvae fed on non-host plant PIs showed significant in vivo inhibition of HaGPPs activation in solution as well as in gel assays. The larvae fed on diet incorporated with Datura alba ness PIs showed highest inhibition of HaGPPs, followed by Psophocarpus tetragonolobus. Non-host plant PIs from Pongamia pinnata, Mucuna pruriens, Capsicum annuum, and Nigela sativa showed maximum inhibitory potential towards HaGPs in vivo, and also exhibited moderate level of inhibition of pro-proteinases. However, some of non-host plant PIs, such as those from Penganum harmala and Solanum nigrum, and the principal host plant PIs, viz., Cicer arietinum and Cajanus cajan did not inhibit HaGPP activity. Pro-proteinase level increased with the growth of the larvae, and maximum HaGPP activity was observed in the fifth-instars. Larvae fed on diets with D. alba ness PIs showed greater inhibition of HaGPPs as compared to the larvae fed on diets with P. tetragonolobus. Low concentrations of partially purified HaGPs treated with gut extract of larvae fed on D. alba ness showed that out of 10 proteinase isoforms, HaGPs 5 and 9 were activators of pro-proteinases. Larval growth and development were significantly reduced in the larvae fed on the non-host plant PIs, of which D. alba ness resulted in highest stunted growth of H. armigera larvae. The in vivo studies indicated that non-host plant PIs were good candidates as inhibitors of the HaGPs as well as HaGPPs. The PIs from the non-host plants can be expressed in genetically engineered plants to confer resistance to H. armigera.     

Differential synthesis of bacteria-induced proteins of Manduca sexta larvae and pupae

The range of inducible antibacterial and other associated haemolymph proteins in Manduca sexta larvae and pupae was examined by high resolution two-dimensional (2D) isoelectric focusing-polyacrylamide gel electrophoresis. Twenty-two major inducible proteins were consistently resolved on gels of haemolymph from bacteria-injected larvae. Haemolymph from bacteria-injected pupae showed a different pattern of induced proteins. The proteins of the two stages include those which (i) are induced in both stages, (ii) those which are exclusively induced in either larvae or pupae, (iii) those which are inducible in larvae, but consititutively present in pupae, and, (iv) those which are induced in larvae, and which are present at intermediate levels but may be induced to higher levels in pupae.The antibacterial activity of the haemolymph from larvae and pupae was compared on acidpolyacrylamide gels, and the apparent M_r and pI of the inducible proteins determined. Certain of the inducible proteins appear to resemble the cecropin and attacin proteins of Hylophora cecropia.