Programmed cell death and stem cell differentiation are responsible for midgut replacement in <Emphasis Type="Italic">Heliothis virescens</Emphasis> during prepupal instar

We have analyzed midgut development during the fifth larval instar in the tobacco budworm Heliothis virescens. In prepupae, the midgut formed during larval instars undergoes a complete renewal process. This drastic remodeling of the alimentary canal involves the destruction of the old cells by programmed cell-death mechanisms (autophagy and apoptosis). Massive proliferation and differentiation of regenerative stem cells take place at the end of the fifth instar and give rise to a new fully functioning epithelium that is capable of digesting and absorbing nutrients and that is maintained throughout the subsequent pupal stage. Midgut replacement in H. virescens is achieved by a balance between this active proliferation process and cell-death mechanisms and is different from similar processes characterized in other insects. This work was supported by FAR 2006 (University of Insubria) to G.T., by a MIUR-FIRB-COFIN grant (no. RBNE01YXA8/2004077251), and by the Centro Grandi Attrezzature (University of Insubria).     

Response of the wasp (<Emphasis Type="Italic">Cotesia glomerata</Emphasis>) to larvae of the large white butterfly (<Emphasis Type="Italic">Pieris brassicae</Emphasis>)

The large white butterfly (Pieris brassicae L) first invaded northernmost Japan from Siberia around 1994, and after a few years, began to expand its range. The wasp, Cotesia glomerata (L) parasitizes larvae of the small white butterfly (Pieris rapae crucivora Boisduval), a usual host in the same geographic area. Some Pieris brassicae larvae in Hokkaido have been parasitized by Cotesia glomerata, but the parasitism rate of Pieris brassicae larvae tends to be lower than that of Pieris rapae. To examine the process of parasitizing Pieris brassicae larvae, we observed how the parasitoid wasp responded to the host larvae on damaged leaves. Cotesia glomerata females tended to avoid Pieris brassicae larvae, and even when female wasps inserted their ovipositors into Pieris brassicae larvae, none laid eggs. The parasitoids obtained from Pieris rapae larvae failed to parasitize Pieris brassicae during the host-acceptance step.     

Host-discrimination by <Emphasis Type="Italic">Phymastichus coffea</Emphasis>, a parasitoid of the coffee berry borer

Phymastichus coffea (LaSalle) (Hymenoptera: Eulophidae) is an African endoparasitoid of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae) that has been introduced to several countries to control this important pest. In the present study we performed a series of laboratory experiments in order to determine if there was evidence of host discrimination and superparasitism in P. coffea. Our choice experiments demonstrate that P. coffea females showed significant preference to attack unparasitized hosts, rather than those parasitized conspecifically. No significant preferences were detected in self-specific attacks between parasitized hosts and the healthy ones. A further dissection of hosts sequentially attacked either self or conspecifically, revealed that there were no more than two eggs per host. As P. coffea is a species that normally allocates two eggs per host in a single attack, we assumed that females were able to attack already parasitized hosts, but they did not lay eggs in them. Based on this fact, we conclude that there is a host discrimination ability in P. coffea females. With respect to the superparasitism by P. coffea using non-choice experiments, there was no significant difference between self-specific or conspecific attacks with respect to the control after one or two successive attacks. Conspecific attacks yielded the largest numbers of eggs after 3rd, 4th and 5th attacks and significant differences were found between this treatment and the control. The maximum number of eggs found in a single host was six individuals (conspecific treatment). These results confirmed that P. coffea usually laid two eggs per host; however, when there are no hosts available, conspecific attacks can result in the superparasitism in this species.     

Synergistic interaction between sublethal doses of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> and <Emphasis Type="Italic">Campoletis chlorideae</Emphasis> in managing <Emphasis Type="Italic">Helicoverpa armigera</Emphasis>

Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) is an important solitary larval endoparasitoid of the tomato fruit borer Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in India. The interaction between Bacillus thuringiensis subspecies kurstaki (Btk) HD-1 and C. chlorideae was studied under laboratory condition to explore their compatibility in managing H. armigera. The results had indicated that the growth and development of H. armigera was affected in a dose-dependent manner upon feeding on sublethal doses of Btk HD-1-treated diets. There were no larval survivors in lethal doses of Btk HD-1 (LC₇₀ and LC₉₀). The growth and survival of the parasitoid were normal when the host larvae were fed with sublethal doses or subjected to short time exposure to lethal doses of Btk HD-1. However, the parasitoid offsprings developed slowly and pupal as well as adult period, adult weight and adult emergence rate were reduced significantly if the parasitoid was developing inside a severely Bt intoxicated host larvae. There were no evident differences in longevity of parasitoid adults that were fed on honey solution containing different concentrations of Btk HD-1 as compared to adults fed only on honey solution. This indicates no direct adverse effect of Btk HD-1 on C. chlorideae. Further, the gravid female parasitoid did not discriminate Btk HD-1 intoxicated and normal H. armigera larvae for oviposition. The result implies that spore crystal formulation of Btk HD-1 can be effectively used in a synergistic manner along with existing natural or prereleased population of C. chlorideae in organic farming or as components in biointensive IPM module for managing H. armigera.     

The influence of two endoparasitic wasps, <Emphasis Type="Italic">Hyposoter didymator</Emphasis> and <Emphasis Type="Italic">Chelonus inanitus</Emphasis>, on the growth and food consumption of their host larva <Emphasis Type="Italic">Spodoptera littoralis</Emphasis>

The influence of parasitism by Hyposoter didymator (Thunberg; Hymenoptera: Ichneumonidae) and Chelonus inanitus (Linnaeus) (Hymenoptera: Braconidae) on the growth and food consumption of their host Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) was studied in the laboratory. Parasitised larvae consumed significantly less artificial diet than unparasitised ones. Egg parasitisation by C. inanitus affected host larval consumption from the second day after emergence and it was significantly different from that of unparasitised ones. H. didymator, however, started to reduce larval consumption 4 days after parasitisation on the third instar host larvae. The overall reduction achieved by the larval endoparasitoid H. didymator is higher than that caused by the egg-larval endoparasitoid C. inanitus. The final body weight of a parasitised host larva by H. didymator and C. inanitus was only 6.7 and 13.0% of the maximum weight of an unparasitised sixth instar larva respectively. Moreover, parasitised larvae never reached the last instar. Results indicated that parasitised larvae might cause considerable less damage to the host plant than unparasitised ones.     

Inhibitory activity of probiotics <Emphasis Type="Italic">Streptococcus phocae</Emphasis> PI80 and <Emphasis Type="Italic">Enterococcus faecium</Emphasis> MC13 against Vibriosis in shrimp <Emphasis Type="Italic">Penaeus monodon</Emphasis>

Occurrence of widespread epizootics among larval and cultured shrimp has put on viable preventive approaches such as application of probiotics on a high priority in aquaculture. In the present study, four probiotics bacteria were isolated from marine fish and shrimp intestine based on the antagonistic activity and nonpathogenic to the host. The isolates of probiotics strains Streptococcus phocae PI80, Enterococcus faecium MC13, Lactococcus garvieae LC149, B49 and one commercial probiotics (ECOFORCE) were fed to post larvae of Penaeus monodon obtained from two different hatcheries to analyze the growth and protection against Vibrio harveyi and V. parahaemolyticus. Growth of P. monodon post larvae fed with probiotic strain S. phocae PI80 was significantly (P < 0.001) higher when compared with control and other three strains in both experiments. The treatment of post larvae with B49 reduced the growth as well as Specific growth rate. Among the three probiotic strains S. phocae PI80 and E. faecium MC13 have effectively inhibited the pathogens. In experiment I high survival (92%) were observed in S. phocae PI80 treated post larvae when challenged with Vibrio harveyi followed by E. faecium MC13 (84%), B49 (76%) and ECOFORCE (68%) but PI80 did not protect the post larvae in the same experiment when they were exposed to V. parahaemolyticus. The probiotic isolate of MC13 has protected the post larvae against V. parahaemolyticus when compared to other probiotics and control. Similarly in the second experiment feeding of S. phocae enhanced the survival of larvae when challenged with V. harveyi. The laboratory studies proved that bacterial probionts S. phocae and E. faecium isolated from shrimp and brackishwater fish has potential applications for controlling pathogenic vibriosis in shrimp culture.     

<Emphasis Type="Italic">Rab32</Emphasis> and the remodeling of the imaginal midgut in <Emphasis Type="Italic">Helicoverpa armigera</Emphasis>

Midgut remodeling is a complex physiological process in holometabolous insects. During midgut remodeling, the larval midgut is decomposed by apoptosis or autophagy during metamorphosis, and the degraded larval midgut is partially absorbed as nutrients by the imaginal midgut for its formation. The molecular mechanism involved in this process is not clear. Here, we found that a Rab protein, which we have named HaRab32, is related to the organogenesis of insect imaginal midgut. Results show that HaRab32 is up-regulated in epidermis and midgut during metamorphosis. Its expression could be up-regulated by 20E. Immunohistochemistry shows Rab32 is distributed in the epithelium of the imaginal midgut during metamorphosis. Knockdown of HaRab32 by RNA interference disturbs the formation of the imaginal midgut. These data imply HaRab32 plays important roles in midgut remodeling by participating in the imaginal midgut formation.     

Phylogenetic analyses of <Emphasis Type="Italic">Uromyces viciae-fabae</Emphasis> and its varieties on <Emphasis Type="Italic">Vicia</Emphasis>, <Emphasis Type="Italic">Lathyrus</Emphasis>, and <Emphasis Type="Italic">Pisum</Emphasis> in Japan

A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan     

Fecundity and feeding of <Emphasis Type="Italic">Galerucella calmariensis</Emphasis> and <Emphasis Type="Italic">G. pusilla</Emphasis> on <Emphasis Type="Italic">Lythrum salicaria</Emphasis>

Fecundity and feeding of two introduced sibling biological control species, Galerucella calmariensis and G. pusilla (Coleoptera: Chrysomelidae) on purple loosestrife, Lythrum salicaria L. (Lythraceae) were compared at constant temperatures of 12.5, 15, 20, 25, and 27.5 °C. Larval feeding was also carried out at 30 °C, but at this temperature, larvae developed only to the L2 stage and none pupated. Thus, data for this temperature were not used in the analysis. There were significant species × temperature interactions in fecundity. Of the two species, Galerucella pusilla laid more eggs. Although egg production of both species was lowest at 12.5 °C and increased to 20 °C, at higher temperatures, the two species reacted differently. From 25 to 27.5 °C, egg production decreased for G. pusilla, but G. calmariensis fecundity peaked at 27.5 °C. Significant temperature × species × life-stage interactions were also observed in feeding. For each species, the amount of feeding varied with temperature and stage of development. Galerucella pusilla adults consumed more foliage at 15, 20, and 27.5 °C. However, at 12.5 °C G. calmariensis adults fed more than G. pusilla. G. pusilla larvae consumed an average of 25% less foliage than G. calmariensis. The lower larval consumption of G. pusilla suggests that when food is limited, G. pusilla larvae may have a higher survival rate because of its ability to complete larval development with less food and produce more progeny due to its greater fecundity. When food is not limited neither species would have a competitive advantage and both species could coexist temporally and spatially. However, since G. calmariensis larvae consumed more leaf material, the larval stage of this species would have a greater impact on purple loosestrife than G. pusilla.     

Functional response and life history parameters of <Emphasis Type="Italic">Apanteles taragamae</Emphasis>, a larval parasitoid of <Emphasis Type="Italic">Maruca vitrata</Emphasis>

The legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) is a serious pest of cowpea in West-Africa. The parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) that originates from Taiwan is a potential candidate for biological control of M. vitrata. We investigated under laboratory conditions the functional response of the parasitoid by offering each experienced female 10, 20, 30 and 40 larvae of M. vitrata. We studied the influence of different host larval ages on the development, longevity, sex ratio, lifetime fecundity and parasitization rate of the wasp. In a comparative study, we also investigated the life history of A. taragamae and M. vitrata at different temperatures in the range of 20–30°C. The parasitoid successfully parasitized two- and three-day-old host larvae (first and second instars). Younger larvae (one-day-old) were parasitized to a lesser extent, and only males developed in them. Older larvae were not parasitized, partly because of defensive host behaviour. The success of parasitization was positively correlated with the density of two-day-old M. vitrata larvae. Parasitoid developmental time and longevity decreased with increasing temperature. The intrinsic rate of population increase (r _m ) exhibited an optimum curve with a maximum at 24–28°C. For the host M. vitrata, r _m was maximal at temperatures of 26–30°C. The data are discussed in the context of the potential of A. taragamae for biological control of M. vitrata.     

Laboratory rearing of <Emphasis Type="Italic">Theileria annulata</Emphasis>-free <Emphasis Type="Italic">Hyalomma anatolicum anatolicum</Emphasis> ticks

Hyalomma anatolicum anatolicum is a three-host tick which transmits Theileria annulata infection in Indian cattle. Laboratory rearing of ixodid ticks is an essential requirement of any laboratory engaged with research on ticks and tick borne diseases. The Entomology laboratory of Indian Veterinary Research Institute is fully equipped with all the facilities and skilled manpower to maintain a homogenous H. a. anatolicum population throughout the year. The continuous supply of eggs, larvae and adults of H. a. anatolicum is maintained to meet out the demand of different experiments viz., preparation of tick antigens for immunization of animals, experimental challenge, isolation of genomic DNA and RNA. Maintenance of a H. a. anatolicum colony free of T. annulata infection is imperative for the experimental challenge infestation on cross-bred (Bos indicus × B. taurus) calves, in order to prevent the transmission of T. annulata infection to the experimental animals. A system has been developed in the laboratory in which the larvae of H. a. anatolicum were fed on New Zealand white rabbits and the dropped fed nymphs molted to adults are fed on cross-bred calves free of T. annulata infection. This synthetic cycle prevents the transstadial transmission of T. annulata as the rabbits are unsusceptible to T. annulata infection and only the adults were fed on cross-bred animals. Moreover, absence of transovarial transmission of T. annulata prevents the chance of carry over infection to experimental animals in the next cycle. Declaration: The experiments have been conducted in accordance with the approved guidelines of Committee for the Purpose of Control and Supervision of Experimentation on Animals (CPCSEA). Besides, the institute animal ethics committee continuously monitored the animal experimentation.     

Acanthocephalan (Oligacanthorhynchidae) parasitism of the Caribbean termite <Emphasis Type="Italic">Nasutitermes acajutlae</Emphasis>: implications for reproductive success

Summary Few studies have examined the impact of parasitism on free-living social insects. We documented the association between an acanthocephalan parasite and survival, reproduction and growth of a Caribbean termite (Nasutitermes acajutlae). We measured these parameters yearly in 100 termite colonies for 4 years. In 2001 and 2002 we also compared the rate at which parasitized and unparasitized colonies rebuilt damaged foraging trails because trails protect foragers from predation as well as fluctuations in temperature and humidity. Although there were no significant differences in growth or survival between parasitized and unparasitized colonies, parasitized colonies reproduced significantly less often and rebuilt foraging trails significantly more slowly than unparasitized colonies. The average parasitized colony may sustain a loss of alate production =30% in the year in which it is parasitized, and a loss of up to 19% if it is parasitized once in a 5-year period. We conclude that the acanthocephalan parasite is associated with significant alteration of fitness parameters of individual N. acajutlae colonies. However, prevalence of parasitism is low (6.8%) and alate production by non-parasitized colonies is likely to compensate for losses due to parasitism. Therefore, it seems unlikely that this parasite affects N. acajutlae at the population level.Received 5 October 2003; revised 19 November 2003; accepted 3 December 2003.     

Nesting biology of the arboreal fungus-growing ant <Emphasis Type="Italic">Cyphomyrmex cornutus</Emphasis> and behavioral interactions with the social-parasitic ant <Emphasis Type="Italic">Megalomyrmex mondabora</Emphasis>

We describe the extraordinary nesting habits of the fungus-growing ant Cyphomyrmex cornutus (Formicidae, Myrmicinae, Attini) and the natural history of Megalomyrmex mondabora (Formicidae, Myrmicinae, Solenopsidini), a social parasite that inhabits nests of C. cornutus and other small attine ants. The study was carried out at two sites on the Atlantic slope of Costa Rica. The C. cornutus nest is an oblong mass of accreted soil, attached to or suspended from low vegetation in wet forest understory. Less than a fourth of the nest volume has chambers and is inhabited by C. cornutus; the remainder is a semi-solid mass of accreted soil often housing a variety of arthropods, including other unspecialized commensal ant species. Five C. cornutus colonies examined were parasitized by M. mondabora. Colonies of M. mondabora inhabited chambers very near those of the host. In laboratory observations, M. mondabora and C. cornutus workers interacted with little aggression despite the consumption of C. cornutus larvae and fungi by M. mondabora. During most interactions, C. cornutus workers responded submissively, whereas M. mondabora appeared indifferent or nonresponsive. Megalomyrmex mondabora parasitizes several other attine species (Cyphomyrmex costatus, Cyphomyrmex salvini, and Apterostigma goniodes), and it appears therefore a relatively unspecialized social parasite with broad attine hostassociation. The size of M. mondabora workers vary with host species, suggesting M. mondabora sensu lato comprises either cryptic species or the host environment affects worker size. Received 14 September 2006; revised 1 February 2007; accepted 6 February 2007.     

Life cycle of <Emphasis Type="Italic">Uromyces appendiculatus</Emphasis> var. <Emphasis Type="Italic">azukicola</Emphasis> on <Emphasis Type="Italic">Vigna angularis</Emphasis>

Field observations and inoculation experiments revealed that Uromyces appendiculatus var. azukicola has an autoecious and macrocyclic life cycle and produces spermogonia, aecia, uredinia, and telia on Vigna angularis var. angularis and V. angularis var. nipponensis. From inoculation experiments, it was suggested that this rust fungus has different host relationships from other varieties. Morphological examinations revealed that the characteristics of urediniospores and teliospores are different among varieties, although aeciospores are morphologically similar to each other.Contribution no. 182, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan     

Toxin-binding proteins isolated from yellow mealworm <Emphasis Type="Italic">Tenebrio molitor</Emphasis> and wax moth <Emphasis Type="Italic">Galleria mellonella</Emphasis>

A 67-kDa protein that can specifically bind the activated Cry9A endotoxin under ligand-blotting conditions was purified from midgut epithelium apical membranes of wax moth Galleria mellonella by affinity chromatography. N-Terminal amino acid sequencing enabled identification of this protein as aminopeptidase N. In similar experiments, 66- and 58-kDa proteins specific to endotoxin Cry3A were isolated from the midgut epithelium apical membranes of Tenebrio molitor larvae. Mass spectrometry showed close similarity of the 58-kDa protein to the Tenebrio molitor α-amylase.     

The <Emphasis Type="Italic">Caenorhabditis</Emphasis><Emphasis Type="Italic">briggsae</Emphasis> genome contains active <Emphasis Type="Italic">CbmaT1</Emphasis> and <Emphasis Type="Italic">Tcb1</Emphasis> transposons

The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.     

Life history of the predatory mite <Emphasis Type="Italic">Phytoseiulus fragariae</Emphasis> on <Emphasis Type="Italic">Tetranychus evansi</Emphasis> and <Emphasis Type="Italic">Tetranychus urticae</Emphasis> (Acari: Phytoseiidae,Tetranychidae) at five temperatures

Tetranychus evansi Baker and Pritchard and Tetranychus urticae Koch (Acari: Tetranychidae) are important pests of Solanaceae in many countries. Several studies have demonstrated that T. urticae is an acceptable prey to many predatory mites, although the suitability of this prey depends on the host plant. T. evansi, has been shown to be an unfavorable prey to most predatory mites that have been tested against it. The predator Phytoseiulus fragariae Denmark and Schicha (Acari: Phytoseiidae) has been found in association with the two species in Brazil. The objective of this work was to compare biological parameters of P. fragariae on T. evansi and on T. urticae as prey. The study was conducted under laboratory conditions at 10, 15, 20, 25 and 30°C. At all temperatures, survivorship was lower on T. evansi than on T. urticae. No predator reached adulthood at 10°C on the former species; even on the latter species, only about 36% of the predators reached adulthood at 10°C. For both prey, in general, duration of each life stage was shorter, total fecundity was lower and intrinsic rate of population increase (r _m ) was higher with increasing temperatures. The slower rate of development of P. fragariae on T. evansi resulted in a slightly higher thermal requirement (103.9 degree-days) on that prey than on T. urticae (97.1 degree-days). The values of net reproduction rate (R ₀), intrinsic rate of increase (r _m ) and finite rate of increase (λ) were significantly higher on T. urticae, indicating faster population increase of the predator on this prey species. The highest value of r _m of the predator was 0.154 and 0.337 female per female per day on T. evansi and on T. urticae, respectively. The results suggested that P. fragariae cannot be considered a good predator of T. evansi.     

A trypsin inhibitor from <Emphasis Type="Italic">Cassia obtusifolia</Emphasis> seeds: isolation,characterization and activity against <Emphasis Type="Italic">Pieris rapae</Emphasis>

A trypsin inhibitor was isolated from Cassia obtusifolia by ammonium sulfate precipitation, Sepharose 4B-trypsin affinity and Sephadex G-75 chromatography. The inhibitor consisted of a single polypeptide chain with a molecular mass of 19, 812.55 Da. It was stable from pH 2 to 12 for 24 h, whereas it was unstable either above 70°C for 10 min or under reduced conditions. The inhibitor, which inhibited trypsin activity with an apparent Ki of 0.3 μM, had one reactive site involving a lysine residue. The native inhibitor was resistant to pepsin digestion, whereas the heated inhibitor produced 40% degree of susceptibility. The disulfide linkage and lysine residue were important in maintaining its conformation. Partial amino acid sequence of the purified protein showed a high degree of homology with various members of the Kunitz inhibitor family. Moreover, the inhibitor showed significant inhibitory activity against trypsin-like proteases present in the larval midgut on Pieris rapae and could suppress the growth of larvae.     

The Bt gene <Emphasis Type="Italic">cry2Aa2</Emphasis> driven by a tissue specific ST-LS1 promoter from potato effectively controls <Emphasis Type="Italic">Heliothis virescens</Emphasis>

Expression of the Cry2Aa2 protein was targeted specifically to the green tissues of transgenic tobacco Nicotiana tabacum cv. Xanthi plants. This deployment was achieved by using the promoter region of the gene encoding the Solanum tuberosum leaf and stem specific (ST-LS1) protein. The accumulated levels of toxin in the leaves were found to be effective in achieving 100 mortality of Heliothis virescens larvae. The levels of Cry2Aa2 expression in the leaves of these transgenic plants were up to 0.21 of the total soluble proteins. Bioassays with R₁ transgenic plants indicated the inheritance of cry2Aa2 in the progeny plants. Tissue-specific expression of the Bt toxin in transgenic plants may help in controlling the potential occurrence of insect resistance by limiting the amount of toxin to only predated tissues. The results reported here validate the use of the ST-LS1 gene promoter for a targeted expression of Bt toxins in green tissues of plants.     

<Emphasis Type="Italic">Toxoplasma gondii</Emphasis> glycosylphosphatidylinositols are not involved in <Emphasis Type="Italic">T. gondii</Emphasis>-induced host cell survival

Toxoplasma gondii is an intracellular parasite able to both promote and inhibit apoptosis. T. gondii renders infected cells resistant to programmed cell death induced by multiple apoptotic triggers. On the other hand, increased apoptosis of immune cells after in vivo infection with T. gondii may suppress the immune response to the parasite. Glycosylphosphatidylinositol (GPI)-anchored proteins dominate the surface of T. gondii tachyzoites and GPIs are involved in the pathogenicity of protozoan parasites. In this report, we determine if GPIs are responsible for inhibition or induction of host cell apoptosis. We show here that T. gondii GPIs fail to block apoptosis that was triggered in human-derived cells via extrinsic or intrinsic apoptotic pathways. Furthermore, characteristics of apoptosis, e.g. caspase-3/7 activity, phosphatidylserine exposition at the cell surface or DNA strand breaks, were not observed in the presence of T. gondii GPIs. These results indicate that T. gondii GPIs are not involved in survival or in apoptosis of host cells. This absence of effect on apoptosis could be a feature common to GPIs of other parasites.