Name game conundrum: identical specific epithets in Microgastrinae (Hymenoptera, Braconidae)

It is a privilege to recognize a new species and immortalize it with a name. Taxonomists may use etymologies recalling the sampling locality, habitat, species morphology, people (actor, writer, singer, politician, scientist), culture (customs, beliefs), fictional characters (gods, demons, cartoons), brands, ancient names, and others. Naming a species is a creative act that allows scientists to express their love for nature. By drawing on personal and cultural associations, species names are often imbued with far greater meaning than one might initially assume. Unconventional names for species can be an effective way to capture the imagination of the public and make the species memorable. In other words, species names can be both meaningful and whimsical. The central focus of this study was to pinpoint species in the subfamily Microgastrinae that share the same specific epithet that often creates confusion regarding which species is being referred to. The findings showed that 153 specific epithets were repeated representing 340 species in 52 genera, while the remaining 2,823 species have unique epithets. Three of the five categories proposed accommodate the majority of the etymologies: people (42%), morphology (27%), and geography (15%) whereas the categories of other (9%) and biology (7%) achieve the least representation. Approximately 95% of the same specific epithets had a single clear meaning, while for the remaining 5%, it was not possible to trace etymology. The study revealed that the average length of specific epithets was 9.01 letters, the longest contains 18 (eliethcantillanoae) while the shortest four (eros and erro). Additionally, most identical specific epithets were repeated two times (85.25% of the occurrences), although three (12.82%), five, six, and even nine (each one with 0.64%) repetitions were also found. Finally, a list of recommendations for taxonomists when faced with the task of naming a new species is provided.

Ophiclypeus, a new genus of Cardiochilinae Ashmead (Hymenoptera, Braconidae) from the Oriental region with descriptions of three new species

A new genus of the braconid subfamily Cardiochilinae, Ophiclypeusgen. nov., is described and illustrated based on three new species: O.chiangmaiensis Kang, sp. nov. type species (type locality: Chiang Mai, Thailand), O.dvaravati Ghafouri Moghaddam, Quicke & Butcher, sp. nov. (type locality: Saraburi, Thailand), and O.junyani Kang, sp. nov. (type locality: Dalin, Taiwan). We provide morphological diagnostic characters to separate the new genus from other cardiochiline genera. A modified key couplet (couplet 5) and a new key couplet (couplet 16) are provided with detailed images for Dangerfield's key to the world cardiochiline genera to facilitate recognition of Ophiclypeusgen. nov.

Arsenophonus: A Double-Edged Sword of Aphid Defense against Parasitoids

It is widely accepted that endosymbiont interactions with their hosts have significant effects on the fitness of both pests and beneficial species. A particular type of endosymbiosis is that of beneficial associations. Facultative endosymbiotic bacteria are associated with elements that provide aphids with protection from parasitoids. Arsenophonus (Enterobacterales: Morganellaceae) is one such endosymbiont bacterium, with infections being most commonly found among the Hemiptera species. Here, black cowpea aphids (BCAs), Aphis craccivora Koch (Hemiptera: Aphididae), naturally infected with Arsenophonus, were evaluated to determine the defensive role of this bacterium in BCAs against two parasitoid wasp species, Binodoxys angelicae and Lysiphlebus fabarum (both in Braconidae: Aphidiinae). Individuals of the black cowpea aphids infected with Arsenophonus were treated with a blend of ampicillin, cefotaxime, and gentamicin (Arsenophonus-reduced infection, AR) and subsequently subjected to parasitism assays. The results showed that the presence of Arsenophonus does not prevent BCAs from being parasitized by either B. angelicae or L. fabarum. Nonetheless, in BCA colonies parasitized by B. angelicae, the endosymbiont delayed both the larval maturation period and the emergence of the adult parasitoid wasps. In brief, Arsenophonus indirectly limits the effectiveness of B. angelicae parasitism by decreasing the number of emerged adult wasps. Therefore, other members of the BCA colony can survive. Arsenophonus acts as a double-edged sword, capturing the complex dynamic between A. craccivora and its parasitoids.

Dietary Challenges for Parasitoid Wasps (Hymenoptera: Ichneumonoidea); Coping with Toxic Hosts, or Not?

Many insects defend themselves against predation by being distasteful or toxic. The chemicals involved may be sequestered from their diet or synthesized de novo in the insects' body tissues. Parasitoid wasps are a diverse group of insects that play a critical role in regulating their host insect populations such as lepidopteran caterpillars. The successful parasitization of caterpillars by parasitoid wasps is contingent upon their aptitude for locating and selecting suitable hosts, thereby determining their efficacy in parasitism. However, some hosts can be toxic to parasitoid wasps, which can pose challenges to their survival and reproduction. Caterpillars employ a varied array of defensive mechanisms to safeguard themselves against natural predators, particularly parasitoid wasps. These defenses are deployed pre-emptively, concurrently, or subsequently during encounters with such natural enemies. Caterpillars utilize a range of strategies to evade detection or deter and evade attackers. These tactics encompass both measures to prevent being noticed and mechanisms aimed at repelling or eluding potential threats. Post-attack strategies aim to eliminate or incapacitate the eggs or larvae of parasitoids. In this review, we investigate the dietary challenges faced by parasitoid wasps when encountering toxic hosts. We first summarize the known mechanisms through which insect hosts can be toxic to parasitoids and which protect caterpillars from parasitization. We then discuss the dietary adaptations and physiological mechanisms that parasitoid wasps have evolved to overcome these challenges, such as changes in feeding behavior, detoxification enzymes, and immune responses. We present new analyses of all published parasitoid-host records for the Ichneumonoidea that attack Lepidoptera caterpillars and show that classically toxic host groups are indeed hosts to significantly fewer species of parasitoid than most other lepidopteran groups.

Two new genera and one new species of the tribe Adeshini (Hymenoptera, Braconidae, Braconinae) from India and South Africa

Two new genera and one new species of the Braconinae tribe Adeshini are described and illustrated: Crenuladesha Ranjith & Quicke, gen. nov., type species Adeshanarendrani Ranjith, 2017, comb. nov. from India, and Protadesha Quicke & Butcher, gen. nov., type species Protadeshaintermedia Quicke & Butcher, sp. nov. from South Africa. The former lacks the mid-longitudinal propodeal carina characteristic of the tribe, and the latter displays less derived fore wing venation with two distinct abscissae of vein 2CU. A molecular phylogenetic analysis is included to confirm their correct placement. Since neither of the two new genera displays all of the characters given in the original diagnosis of the Adeshini a revised diagnosis is provided, as well as an illustrated key to the genera.

Microplitis manilae Ashmead (Hymenoptera: Braconidae): Biology, Systematics, and Response to Climate Change through Ecological Niche Modelling

The parasitoid wasp Microplitis manilae Ashmead (Braconidae: Microgastrinae) is an important natural enemy of caterpillars and of a range of noctuids, including pest species of armyworms (Spodoptera spp.). Here, the wasp is redescribed and, for the first time, illustrated based on the holotype. An updated list of all the Microplitis species attacking the noctuid Spodoptera spp. along with a discussion on host-parasitoid-food plant associations is offered. Based on information about the actual distribution of M. manilae and a set of bioclimatic variables, the maximum entropy (MaxEnt) niche model and the quantum geographic information system (QGIS) were explored to predict the potential distribution of this wasp in a global context. The worldwide geographical distribution of potential climatic suitability of M. manilae at present and in three different periods in the future was simulated. The relative percent contribution score of environmental factors and the Jackknife test were combined to identify dominant bioclimatic variables and their appropriate values influencing the potential distribution of M. manilae. The results showed that under current climate conditions, the prediction of the maximum entropy model highly matches the actual distribution, and that the obtained value of simulation accuracy was very high. Likewise, the distribution of M. manilae was mainly affected by five bioclimatic variables, listed in order of importance as follows: precipitation during the wettest month (BIO13), annual precipitation (BIO12), annual mean temperature (BIO1), temperature seasonality (BIO4), and mean temperature during the warmest quarter (BIO10). In a global context, the suitable habitat of M. manilae would be mainly in tropical and subtropical countries. Furthermore, under the four greenhouse gas concentration scenarios (representative concentration pathways: RCP2.6, RCP4.5, RCP6.0, and RCP8.5) in the future period of the 2070s, the areas with high, medium, and low suitability showed varying degrees of change from current conditions and are expected to expand in the future. This work provides theoretical backing for studies associated with the safeguarding of the environment and pest management.

A new species of the long-tailed wasp genus Euurobracon Ashmead (Hymenoptera, Braconidae, Braconinae) from Java, Indonesia, is described and the type species redescribed

A new species, Euurobraconbhaskarai Quicke, sp. nov., from West Java, Indonesia, is described, illustrated and differentiated from other members of the genus. It is closely related to the type species of the genus, E.yokahamae Dalla Torre, 1898, which is known from China, India, Japan, Laos, South Korea and Thailand. Euurobraconyokahamae is redescribed and illustrated for comparative purposes. The two species are separable mainly on colouration, but differ markedly based on their mitochondrial gene sequences (cytochrome c oxidase I, cytochrome b and 16S rDNA). The slower-evolving nuclear 28S rDNA and elongation factor 1-alpha did not differentiate E.bhaskarai sp. nov. from E.yokahamae, but consistently split Euurobracon into two species groups.

Completely predatory development is described in a braconid wasp

Hymenopteran parasitoids are well known for their ubiquitous diversity, important ecological roles and biocontrol potential. We report the first detailed documentation of mite predation by a parasitoid wasp, Bracon predatorius Ranjith & Quicke sp. nov., (Insecta: Hymenoptera), first case of obligate predatory behaviour in the family Braconidae and first case of mite feeding within the superfamily Ichneumonoidea. Larvae of a new wasp species are shown to develop entirely as predators of eriophyid mites that induce leaf galls in a commercially important plant. They display highly modified head capsule morphology that we interpret as being associated with this atypical life style. We propose that the new feeding strategy evolved separately from recently described entomophytophagy in another species of the same genus. The divergent larval morphological adaptations of both species indicate a high degree of evolutionary developmental plasticity in the developmental stage.

Review of Venoms of Non-Polydnavirus Carrying Ichneumonoid Wasps

Parasitoids are predominantly insects that develop as larvae on or inside their host, also usually another insect, ultimately killing it after various periods of parasitism when both parasitoid larva and host are alive. The very large wasp superfamily Ichneumonoidea is composed of parasitoids of other insects and comprises a minimum of 100,000 species. The superfamily is dominated by two similarly sized families, Braconidae and Ichneumonidae, which are collectively divided into approximately 80 subfamilies. Of these, six have been shown to release DNA-containing virus-like particles, encoded within the wasp genome, classified in the virus family Polydnaviridae. Polydnaviruses infect and have profound effects on host physiology in conjunction with various venom and ovarial secretions, and have attracted an immense amount of research interest. Physiological interactions between the remaining ichneumonoids and their hosts result from adult venom gland secretions and in some cases, ovarian or larval secretions. Here we review the literature on the relatively few studies on the effects and chemistry of these ichneumonoid venoms and make suggestions for interesting future research areas. In particular, we highlight relatively or potentially easily culturable systems with features largely lacking in currently studied systems and whose study may lead to new insights into the roles of venom chemistry in host-parasitoid relationships as well as their evolution.

A new genus and species of Neotropical gregarious braconine parasitoid (Hymenoptera: Braconidae) of a caterpillar (Lepidoptera: Hesperiidae)

A new genus of braconine parasitoid wasp, Acgorium Sharkey Quicke gen. nov., based on a new species from Costa Rica, Acgorium felipechavarriai Sharkey sp. nov., is described and illustrated, based on specimens reared from wild-caught hesperiid caterpillars of Dyscophellus phraxanor (Hewitson). Acgorium felipechavarriai is the first known braconine gregarious ectoparasitoid of a butterfly caterpillar.

Phylogenetic reassignment of basal cyclostome braconid parasitoid wasps (Hymenoptera) with description of a new, enigmatic Afrotropical tribe with a highly anomalous 28S D2 secondary structure

A new tribe of braconid wasps provisionally included in the Rhyssalinae, Laibaleini trib. nov., type genus Laibalea gen. nov. (type species Laibalea enigmatica sp. nov.), from Kenya and the Central African Republic, is described. A molecular dataset, with emphasis on basally derived taxa based on four gene fragments (28S D2–D3 expansion region, COI barcode, elongation factor 1-alpha and 16S ribosomal DNA), was analysed both alone and in combination with a morphological dataset. Molecular phylogenetic placement of the new species into an existing subfamily is complicated by the extreme sequence divergence of the three sequences obtained for Laibalea. In both the combined sequence analysis and the combined DNA plus morphological tree, Laibalea is recovered as a sister group to the Rhyssalinae plus all non-cyclostome lineage braconids excluding Mesostoinae, Maxfischeriinae and Aphidiinae. A consensus of morphological characters and molecular analyses suggests inclusion of Laibalea either in the otherwise principally Holarctic subfamily Rhyssalinae or perhap more basally, in the principally Gondwanan Mesostoinae s.l., although we cannot exclude the possibility that it might represent a separate basal lineage. We place Laibalea in its own tribe, provisionally included in Rhyssalinae. The DNA sequence data are presented for several genera for the first time. Avga, the type genus of Avgini, is shown not to belong to Mesostoinae s.l. or Hormiinae, but its exact relationships remain uncertain. The generic compositions of Rhyssalinae and Mesostoinae s.l. are revised. Anachyra, Apoavga, Neptihormius, Neoavga and Opiopterus are shown to belong to Mesostoinae s.s. A key to the tribes of Rhyssalinae is provided.

The genus Vipio Latreille (Hymenoptera, Braconidae) in the Neotropical Region

The genus Vipio Latreille is revised for the Neotropical region (south of Nicaragua). All species are fully illustrated. Thirteen species are recognised of which five (V.boliviensis, V.carinatus, V.godoyi, V.hansoni, and V.lavignei) are described as new, all with descriptions attributable to Inayatullah, Shaw & Quicke. All previously described Neotropical species are redescribed. A key is included for the identification of the Vipio species known from the Americas south of Nicaragua, and all species are illustrated.

First record of Odontosphaeropyx Cameron, 1910 from the Oriental Region with description of a new species from Thailand (Hymenoptera, Braconidae, Cheloninae)

Odontosphaeropyxmatasi Quicke & Butcher, sp. n. from Thailand is described and illustrated. The new species represents the first known record of Odontosphaeropyx from outside of the Afrotropical Region. A key is provided to separate it from the apparently closely related O.flavifasciatus Zettel, 1990, with which it shares almost identical colouration, very different from the other five known species.

A new species of Cedria Wilkinson (Hymenoptera: Braconidae: Lysiterminae) from Thailand

The Old World, cyclostome braconid wasp genus Cedria Wilkinson is recorded from Thailand for the first time based on a new species, Cedria wichasei Quicke, Belokobylskij Butcher, sp. nov., which is described, illustrated, and a key provided to enable its separation from the closely-related species, C. galinae Belokobylskij and C. africana Belokobylskij which share strong peri-occular carina and at least rather rugose frons. Similarities to Apocedria van Achterberg Chen, from China, are discussed.

An enigmatic new genus of Hormiinae (Hymenoptera: Braconidae) from South India

A new Hormiinae genus Indohormius gen. nov. with type species I. keralensis sp. nov. is described and illustrated. Comparison of this genus with some Hormiinae and Rhyssalinae genera are provided. The composition of the subfamily Hormiinae and the position of the new genus on a molecular phylogenetic tree are discussed.

New species of Bacuma Cameron (Hymenoptera: Braconidae: Braconinae) from Kenya and West Darfur with a key to species

Three new species of the Afrotropical braconine wasp genus Bacuma are described, and biological observations (nectar feeding) by one of them are noted. The new species are: B. kayserae Quicke & Butcher sp. nov. from Kenya, B. madiensis Quicke & Butcher sp. nov. from Uganda and B. darfurensis Quicke & Butcher sp. nov. from Sudan. A group of four large nominal species with red metasomas and finely sculptured tergites (B. granulatus, B. maculipennis, B. rufa and B. whitei) may represent a single widespread species or a pair of species separated by mesoscutum colour, or four separate but morphologically very similar species. However, given the small number of specimens available for study and the poor condition of some of these, including the types, they are not formally synonymised here. A partial key to the species of Bacuma is presented, which recognizes those species that are clearly distinct, including three new species. Interactive Lucid dichotomous and matrix keys are available on www.waspweb.org.

Revision of the non-Afrotropical species of <i>Trigastrotheca</i> Cameron (Hymenoptera: Braconidae: Braconinae) with descriptions of four new species

The Asian species of Trigastrotheca are revised. Four species are described as new: T. pariyanonthae sp. nov. from Thailand, T. sureeratae sp. nov. from Thailand, T. luzonensis sp. nov. from the Philippines, and T. maetoi sp. nov. from Indonesia (Kalimantan). Trigastrotheca tridentata (Enderlein) is redescribed and recorded from India for the first time. A key is provided to differentiate all non-Afrotropical species of the genus.

Entomophytophagy ('Sequential Predatory, then Phytophagous Behaviour') in an Indian Braconid 'Parasitoid' Wasp (Hymenoptera): Specialized Larval Morphology, Biology and Description of a New Species

The vast majority of braconid wasps are parasitoids of other insects. Although a few cases of pure phytophagy (primary gall production and seed predation) are known, no previous entomophytophagous species (i.e. ones that display entomophagy and phytophagy sequentially), has been discovered among braconids. We describe the detailed biology and specialized larval morphology for the first confirmed entomophytophagous braconid species. Leaf galls on Garuga pinnata Roxb. (Burseraceae) in India, induced by the psyllid, Phacopteron lentiginosum Buckton (Hemiptera: Psylloidea, Phacopteronidae) were sampled throughout a period of several months and found to suffer a high level of attack by a new species Bracon garugaphagae Ranjith & Quicke which is here described and illustrated. The wasps oviposit singly into the galls without paralysing the psyllids. The larvae first attack psyllid nymphs which they seek out within the gall, kill them with a single bite and consume them. Unique dorsal abdominal tubercles, with eversible tips present on the abdominal segments of the larvae that are used to help maintain larval position while feeding, are illustrated. After consuming all available prey, the larvae continue feeding on gall tissue until mature enough to spin cocoons and pupate. The new species illustrates, for the first time, a possible intermediate stage in the evolution of pure phytophagy within the Braconidae. Interestingly, the two unrelated seed predator Bracon species are also associated with Burseraceae, perhaps indicating that this plant family is particularly suited as a food for braconine wasps.

Major range extensions for two genera of the parasitoid subtribe Facitorina, with a new generic synonymy (Braconidae, Rogadinae, Yeliconini)

The genera Conobregma van Achterberg and Facitorus van Achterberg are recorded from the Afrotropical region and the Indian subcontinent, respectively, for the first time, and two new species are described and illustrated: Conobregma bradpitti Quicke & Butcher, sp. n. from South Africa and Facitorus nasseri Ranjith & Quicke, sp. n. from India. Conobregma bradpitti sp. n. is intermediate between Conobregma which was described originally from the New World, and Asiabregma Belokobylskij, Zaldivar-Riverón & Maetô, which was coined for the S. E. Asian and East Palaearctic (Japanese) species described under the name Conobregma, plus more recently discovered taxa, but the differences between these genera are few and slight. Of the four previously proposed diagnostic characters for separating Asiabregma from Conobregma, the new species shares two with each, and therefore, the two genera are formally synonymised. Facitorus was previously known only from the East Palaearctic region and from S. E. Asia (Japan, Nepal, Taiwan and Vietnam).

First record of Aleiodes (Hemigyroneuron) (Hymenoptera: Braconidae: Rogadinae) from the Arabian Peninsula: description of new species with remarkable wing venation convergence to Gyroneuron and Gyroneuronella

A new species of Aleiodes (Hemigyroneuron) from Saudi Arabia is described and illustrated. It represents the first species known from outside of sub-Saharan Africa, Madagascar, South East Asia and the East Palaearctic. It belongs to a species group comprising A. (H.) plurivena, glandularis and sharkeyi, but displays even more derived wing venation which is remarkably convergent with that of two distantly related rogadine genera, Gyroneuron and Gyroneuronella.

Description of a new Betylobraconini-like parasitoid wasp genus and species (Hymenoptera: Braconidae: Rogadinae) from Chile

Gondwanocentrus gen. nov. (type species Gondwanocentrus humphriesi sp. nov.) from Chile is described and illustrated. Morphological and weak molecular evidence indicate that the new genus may be a basal member of the Betylobraconini. The molecular data analysed to assess its placement additionally draw into question the relationship between Betylobraconini and Clinocentrini. Previously, the Betylobraconini were known only from the Australasian region, Oceania and Eocene Europe (Baltic amber), thus if Gondwanocentrus gen. nov. does belong to this group it confirms the groups present day Gondwanan distribution.

Preembobracon gen. nov. (Hymenoptera: Braconidae: Doryctinae: Ypsistocerini: Embobraconina) from Brazil

Preembobracon zaldivarriveroni gen et sp. nov. from Brazil is described and illustrated. It belongs to the poorly known tribe Ypsistocerini for which biology, is only partly known and then only for the genera of nominal subtribe which are both associated with termite colonies. Preembobracon displays both derived and plesiomorphic character states relative to Embobracon the only other genus of its tribe, and its position in relation to the other genera discussed. Its biology is unknown.

A new species of the genus Serrundabracon van Achterberg (Hymenoptera: Braconidae: Braconinae) from Namibia

A second species of the braconine genus Serrundabracon is described and illustrated and distinguished from the type species, S. maraisi Braet. Both species possess the unique combination of a multiple-arched ovipositor and dentate posterior margin to the metasomal tergite 5. Corrections are made to the redescription of S. maraisi. The relationships of, and possible evolutionary transitions to, the genus are discussed.

A new Australian genus and five new species of Rogadinae (Hymenoptera: Braconidae), one reared as a gregarious endoparasitoid of an unidentified limacodid (Lepidoptera)

Teresirogas Quicke & Shaw gen. nov. (type species T. australicolorus Quicke & Shaw sp. nov.) is described and illustrated, based on a series recently reared gregariously from a cocooned mummy of an unidentified species of Limacodidae collected under loose Eucalyptus bark in New South Wales, Australia. Older reared and unreared congeneric specimens represent four additional species, T. billbrysoni Quicke & van Achterberg sp. nov., T. nolandi Quicke & Butcher sp. nov., T. prestonae Quicke & van Achterberg sp. nov., and T. williamsi Quicke & van Achterberg sp. nov., which are also described and illustrated. Three of these additional species have also been reared from Limacodidae cocoons on Eucalyptus, with one, perhaps erroneous, record suggesting a saturniid host. Molecular analysis confirms the placement of the new type species of Teresirogas in the tribe Rogadini, as inferred initially from the claws with pointed basal lobe and host relationships of some of the species, but one species has the claw character poorly developed which had made its affinities uncertain before the more recently reared and sequenceable material became available.

Dysregulation of macrophage signal transduction by Toxoplasma gondii: past progress and recent advances

The opportunistic protozoan parasite Toxoplasma gondii is well known as a strong inducer of cell-mediated immunity, largely as a result of proinflammatory cytokine induction during in vivo infection. Yet, during intracellular infection the parasite suppresses signal transduction pathways leading to these proinflammatory responses. The opposing responses are likely to reflect the parasite's need to stimulate immunity allowing host survival and parasite persistence, and at the same time avoiding excessive responses that could result in parasite elimination and host immunopathology. This Review summarizes past and present investigations into the effects of Toxoplasma on host cell signal transduction. These studies reveal insight into the profound suppression of proinflammatory cytokine responses that occurs when the parasite infects macrophages and other cells of innate immunity.

Functional aspects of Toll-like receptor/MyD88 signalling during protozoan infection: focus on Toxoplasma gondii

Toll-like receptor (TLR)/MyD88 signalling has emerged as a major pathway of pathogen recognition in the innate immune system. Here, we review recent data that begin to show how this pathway controls the immune response to protozoan infection, with particular emphasis on the opportunistic pathogen Toxoplasma gondii. The various ways that the parasite activates and suppresses TLR/MyD88 signalling defines several key principals that illuminate the complexities of the host-pathogen interaction. We also speculate how TLR/MyD88 signalling might be exploited to provide protection against Toxoplasma, as well as other protozoa and infection in general.

Toxoplasma gondii tachyzoites inhibit proinflammatory cytokine induction in infected macrophages by preventing nuclear translocation of the transcription factor NF-kappa B

Control of microbial infection requires regulated induction of NF-kappaB-dependent proinflammatory cytokines such as IL-12 and TNF-alpha. Activation of this important transcription factor is driven by phosphorylation-dependent degradation of the inhibitory IkappaB molecule, an event which enables NF-kappaB translocation from the cytoplasm to the nucleus. In this study, we show that intracellular infection of macrophages with the protozoan parasite Toxoplasma gondii induces rapid IkappaB phosphorylation and degradation. Nevertheless, NF-kappaB failed to translocate to the nucleus, enabling the parasite to invade cells without triggering proinflammatory cytokine induction. Infected cells subsequently subjected to LPS triggering were severely crippled in IL-12 and TNF-alpha production, a result of tachyzoite-induced blockade of NF-kappaB nuclear translocation. Our results are the first to demonstrate the ability of an intracellular protozoan to actively interfere with the NF-kappaB activation pathway in macrophages, an activity that may enable parasite survival within the host.

Rapid recruitment of neutrophils containing prestored IL-12 during microbial infection

Neutrophils are well known to rapidly migrate to foci of infection, where they exert microbicidal functions. We sought to determine whether neutrophils responding to in vivo infection with the protozoan pathogen Toxoplasma gondii were capable of IL-12 production as suggested by recent in vitro studies. Intraperitoneal infection induced a neutrophil influx by 4 h, accompanied by ex vivo IL-12 p40 and p70 release. Approximately 85% of the neutrophils displayed intracellular stores of IL-12, as determined by flow cytometry and confocal fluorescence microscopy. Neutrophils from IFN-gamma knockout mice also expressed IL-12, ruling out an IFN-gamma-priming requirement. Neither infected nor uninfected peritoneal macrophages displayed intracellular IL-12, but these cells were strongly IL-10(+). Infection per se was unnecessary for IL-12 production because peritoneal and peripheral blood neutrophils from uninfected animals contained IL-12(+) populations. Expression of the granulocyte maturation marker Gr-1 (Ly-6G) was correlated with IL-12 production. Mice depleted of their granulocytes by mAb administration at the time of infection had decreased serum levels of IL-12 p40. These results suggest a model in which neutrophils with prestored IL-12 are rapidly mobilized to an infection site where they are triggered by the parasite to release cytokine. Our findings place neutrophils prominently in the cascade of early events leading to IL-12-dependent immunity to T. gondii.

Larvae-induced plasma membrane wounds and glycoprotein deposition are insufficient for Trichinella spiralis invasion of epithelial cells

Trichinella spiralis L1 larvae infect susceptible hosts by invading epithelial cells that line the small intestine. Invasion also occurs in vitro when larvae are inoculated into cultures of epithelial cells from several different animal species. To further investigate the mechanism of invasion, we studied the interaction of larvae with the rat epithelial cell line IEC-6. Larvae did not invade IEC-6 cells, but did cause the cells to take up parasite glycoproteins. Glycoprotein bearing cells remained viable and were detectable in monolayers for as long as 24 h, suggesting that the glycoproteins were not toxic for cells. Immunofluorescence revealed that parasite glycoproteins localized in the nuclei, mitochondria and cytoplasm and we found evidence for selection of certain molecules between nuclear and cytoplasmic compartments. Using fluorescent dextrans as fluid phase markers we found 17-38% of the cells in inoculated monolayers were engorged with dextran and that dextran was free in the cytoplasm. Increased dextran uptake was not lethal, required the presence of activated larvae, and was often associated with uptake of parasite glycoproteins. These observations suggest that larvae caused plasma membrane wounds. Our results showed that neither delivery of glycoproteins nor mechanical wounding is sufficient to allow entry of the parasite into resistant epithelial cells. Because both invasion-resistant and susceptible epithelial cells undergo non-lethal wounding, we propose that larvae-induced injury to epithelial cells may result in release of cell-specific mediators that signal larva to invade a particular cell line or, alternatively, to ignore it.

Perforin-mediated cytolysis plays a limited role in host resistance to Toxoplasma gondii

Resistance of perforin knockout (PKO) mice to infection with Toxoplasma gondii was assessed in models of acute infection and during chronic disease. PKO mice vaccinated with the attenuated mutant, ts-4, displayed severely defective CTL responses against tachyzoite-infected targets. Lysis of the NK target, YAC-1, was also severely impaired in PKO mice following ts-4 vaccination. In contrast, wild-type mice developed high levels of CTL and NK lytic activity after ts-4 vaccination. Despite severely defective lytic activity, vaccinated PKO animals were completely resistant to challenge with the virulent strain RH, which normally causes a lethal acute infection. Resistance was attributable to production of IFN-gamma, which remained unimpaired in the PKO animals. In contrast, when PKO mice were infected with low virulence parasite strain ME49, which progresses to the cyst-forming stage after passage through an acute phase, accelerated mortality was observed beginning at 75 days postinfection. A three- to fourfold increase in brain cyst numbers was also found by day 30 in infected PKO animals. Nevertheless, the PKO strain produced normal levels of IFN-gamma after ME49 infection, ruling out impaired production of the latter cytokine as a cause of increased susceptibility. Together, these results show that perforin-dependent cytolytic function is not required for host resistance to lethal acute infection in preimmunized animals, but that the latter activity contributes to the control of infection during the chronic stage.

Perforin-mediated cytolysis plays a limited role in host resistance to Toxoplasma gondii

Resistance of perforin knockout (PKO) mice to infection with Toxoplasma gondii was assessed in models of acute infection and during chronic disease. PKO mice vaccinated with the attenuated mutant, ts-4, displayed severely defective CTL responses against tachyzoite-infected targets. Lysis of the NK target, YAC-1, was also severely impaired in PKO mice following ts-4 vaccination. In contrast, wild-type mice developed high levels of CTL and NK lytic activity after ts-4 vaccination. Despite severely defective lytic activity, vaccinated PKO animals were completely resistant to challenge with the virulent strain RH, which normally causes a lethal acute infection. Resistance was attributable to production of IFN-gamma, which remained unimpaired in the PKO animals. In contrast, when PKO mice were infected with low virulence parasite strain ME49, which progresses to the cyst-forming stage after passage through an acute phase, accelerated mortality was observed beginning at 75 days postinfection. A three- to fourfold increase in brain cyst numbers was also found by day 30 in infected PKO animals. Nevertheless, the PKO strain produced normal levels of IFN-gamma after ME49 infection, ruling out impaired production of the latter cytokine as a cause of increased susceptibility. Together, these results show that perforin-dependent cytolytic function is not required for host resistance to lethal acute infection in preimmunized animals, but that the latter activity contributes to the control of infection during the chronic stage.

Deficiency in beta1,3-galactosyltransferase of a Leishmania major lipophosphoglycan mutant adversely influences the Leishmania-sand fly interaction

To study the function of side chain oligosaccharides of the cell-surface lipophosphoglycan (LPG), mutagenized Leishmania major defective in side chain biosynthesis were negatively selected by agglutination with the monoclonal antibody WIC79.3, which recognizes the galactose-containing side chains of L. major LPG. One such mutant, called Spock, lacked the ability to bind significantly to midguts of the natural L. major vector, Phlebotomus papatasi, and to maintain infection in the sand fly after excretion of the digested bloodmeal. Biochemical characterization of Spock LPG revealed its structural similarity to the LPG of Leishmania donovani, a species whose inability to bind to and maintain infections in P. papatasi midguts has been strongly correlated with the expression of a surface LPG lacking galactose-terminated oligosaccharide side chains. An in vitro galactosyltransferase assay using wild-type or Spock membranes was used to determine that the defect in Spock LPG biosynthesis is a result of defective beta1,3-galactosyltransferase activity as opposed to a modification of LPG, which would prevent it from serving as a competent substrate for galactose addition. The results of these experiments show that Spock lacks the beta1, 3-galactosyltransferase for side chain addition and that the LPG side chains are required for L. major to bind to and to produce transmissible infection in P. papatasi.

Ligand-induced adhesion to activated endothelium and to vascular cell adhesion molecule-1 in lymphocytes transfected with the N-formyl peptide receptor

Binding of FMLP to the neutrophil N-formyl peptide receptor (FPR) transmits signals through pertussis toxin-sensitive G proteins triggering Ca2+ flux, superoxide production, granule exocytosis, and neutrophil aggregation and adhesion involving the beta 2 (CD18) integrins. Expression of the FPR in mouse fibroblasts or human kidney cells has been shown to confer an N-formyl peptide-inducible Ca2+ flux in transfectants. Here we demonstrate that the transfected receptor can also support ligand-induced alterations in cellular adhesion. We established stable transfectants of mouse L1-2 pre-B cells with cDNA for human FPR (L1-2 FPR cells). The transfectants bind N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein with 1.4 x 10(5) sites per cell and a dissociation constant of 3.3 nM. Stimulation with FMLP induces a transient Ca2+ flux. FMLP also triggers adhesion of L1-2 FPR cells to TNF-alpha- or LPS-activated bEnd3 cells (mouse brain-derived endothelial cells) and to purified mouse VCAM-1. Binding is inhibited by Abs to VCAM-1 and to the alpha-chain of its lymphocyte receptor (the alpha 4 beta 1 integrin, VLA-4). Stimulation with FMLP does not induce a change in cell surface expression of alpha 4. Induced adhesion to VCAM-1 is rapid, detectable at the earliest times measurable (30 to 60 s after FMLP addition), and is inhibited by pertussis toxin. We conclude that FPR can mediate integrin activation not only in neutrophils but also in lymphocytes, and can trigger rapid adhesion via lymphocyte alpha 4 beta 1. The adhesion of lymphocytes is critical to their migration and targeting; our results suggest the possibility of manipulating adhesive responses through expression of chemoattractant receptors in lymphoid cells engineered for cellular therapy, allowing targeted adhesion and potentially migration in response to locally administered ligands.

Ligand-induced adhesion to activated endothelium and to vascular cell adhesion molecule-1 in lymphocytes transfected with the N-formyl peptide receptor

Binding of FMLP to the neutrophil N-formyl peptide receptor (FPR) transmits signals through pertussis toxin-sensitive G proteins triggering Ca2+ flux, superoxide production, granule exocytosis, and neutrophil aggregation and adhesion involving the beta 2 (CD18) integrins. Expression of the FPR in mouse fibroblasts or human kidney cells has been shown to confer an N-formyl peptide-inducible Ca2+ flux in transfectants. Here we demonstrate that the transfected receptor can also support ligand-induced alterations in cellular adhesion. We established stable transfectants of mouse L1-2 pre-B cells with cDNA for human FPR (L1-2 FPR cells). The transfectants bind N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein with 1.4 x 10(5) sites per cell and a dissociation constant of 3.3 nM. Stimulation with FMLP induces a transient Ca2+ flux. FMLP also triggers adhesion of L1-2 FPR cells to TNF-alpha- or LPS-activated bEnd3 cells (mouse brain-derived endothelial cells) and to purified mouse VCAM-1. Binding is inhibited by Abs to VCAM-1 and to the alpha-chain of its lymphocyte receptor (the alpha 4 beta 1 integrin, VLA-4). Stimulation with FMLP does not induce a change in cell surface expression of alpha 4. Induced adhesion to VCAM-1 is rapid, detectable at the earliest times measurable (30 to 60 s after FMLP addition), and is inhibited by pertussis toxin. We conclude that FPR can mediate integrin activation not only in neutrophils but also in lymphocytes, and can trigger rapid adhesion via lymphocyte alpha 4 beta 1. The adhesion of lymphocytes is critical to their migration and targeting; our results suggest the possibility of manipulating adhesive responses through expression of chemoattractant receptors in lymphoid cells engineered for cellular therapy, allowing targeted adhesion and potentially migration in response to locally administered ligands.

Decreased renal excretion of beta-hexosaminidase in adults with insulin-dependent diabetes mellitus and normal renal function

The activities of three lysosomal hydrolases and creatinine levels were measured in the plasma and urine of 11 adults (mean age, 28.1 years) with insulin-dependent diabetes mellitus and 14 non-diabetic controls (mean age, 27.9 years). All of the patients were free of diabetic complications and non exhibited microalbuminuria. Fractional enzyme excretion (FEE) values between the two groups of subjects were calculated and compared for the following enzymes: beta-hexosaminidase (N-acetyl-glucosaminidase), beta-glucuronidase and alpha-galactosidase. The FEE value was calculated as the ratio of enzyme clearance to creatinine clearance. Relative to the non-diabetic control group, the FEE value for beta-hexosaminidase was approximately 2-fold lower (P = 0.02) in the diabetic subjects (means, 0.424 vs. 0.242, respectively). The FEE values for beta-glucuronidase and alpha-galactosidase were not significantly different (P > 0.4) between the diabetic and control groups. These easily measured biochemical parameters in blood and urine and the resultant FEE value for beta-hexosaminidase may provide a means of assessing subtle deteriorative changes in renal function which occur in the early stage of diabetes before the onset of clinically evident complications.

Heparin enhances the interaction of infective Leishmania donovani promastigotes with mouse peritoneal macrophages. A fluorescence flow cytometric analysis

Human visceral leishmaniasis results from the infection of macrophages by the protozoan parasite Leishmania donovani. Both forms of the parasite, the extracellular promastigote and the obligate intracellular amastigote, require cell surface molecules to ensure their recognition and uptake by the host cell, the macrophage. We have proposed previously that the heparin-binding protein on the surface of promastigotes is an adhesion molecule. The present report provides experimental evidence to support this hypothesis. Fluorescence flow cytometry using FITC-heparin was employed to study the heparin-binding protein of L. donovani promastigotes and amastigotes. We demonstrate the presence of the heparin-binding protein on the surface of amastigotes and document the heparin specificity of the binding protein for both forms of the parasite. Two-color fluorescence analysis was performed to compare R-PNA reactivity and FITC-heparin binding during the parasite's 7-day growth curve. Using this strategy we show that the expression of heparin binding activity coincides with the differentiation of the noninfective promastigote into the infective metacyclic from of the parasite. Macrophages that were challenged for 30 min with heparin-treated, FITC-labeled parasites became 2.82-fold more fluorescent than their counterparts which were exposed to non-heparin-treated FITC-labeled promastigotes. Finally, using Kolmogorov-Smirnov analysis we show that the adhesion of promastigotes to mouse peritoneal macrophages is significantly enhanced in the presence of 3.3 microM heparin. The experiments described in the present report provide evidence for the hypothesis that L. donovani's heparin-binding protein is a virulence factor that functions as an adhesion molecule in the parasite-macrophage interaction.

Heparin enhances the interaction of infective Leishmania donovani promastigotes with mouse peritoneal macrophages. A fluorescence flow cytometric analysis

Human visceral leishmaniasis results from the infection of macrophages by the protozoan parasite Leishmania donovani. Both forms of the parasite, the extracellular promastigote and the obligate intracellular amastigote, require cell surface molecules to ensure their recognition and uptake by the host cell, the macrophage. We have proposed previously that the heparin-binding protein on the surface of promastigotes is an adhesion molecule. The present report provides experimental evidence to support this hypothesis. Fluorescence flow cytometry using FITC-heparin was employed to study the heparin-binding protein of L. donovani promastigotes and amastigotes. We demonstrate the presence of the heparin-binding protein on the surface of amastigotes and document the heparin specificity of the binding protein for both forms of the parasite. Two-color fluorescence analysis was performed to compare R-PNA reactivity and FITC-heparin binding during the parasite's 7-day growth curve. Using this strategy we show that the expression of heparin binding activity coincides with the differentiation of the noninfective promastigote into the infective metacyclic from of the parasite. Macrophages that were challenged for 30 min with heparin-treated, FITC-labeled parasites became 2.82-fold more fluorescent than their counterparts which were exposed to non-heparin-treated FITC-labeled promastigotes. Finally, using Kolmogorov-Smirnov analysis we show that the adhesion of promastigotes to mouse peritoneal macrophages is significantly enhanced in the presence of 3.3 microM heparin. The experiments described in the present report provide evidence for the hypothesis that L. donovani's heparin-binding protein is a virulence factor that functions as an adhesion molecule in the parasite-macrophage interaction.

Leishmania donovani: cell-surface heparin receptors of promastigotes are recruited from an internal pool after trypsinization

With the use of [3H]heparin, we recently demonstrated that Leishmania donovani promastigotes express a cell-surface receptor that is specific for the glycosaminoglycan heparin (Mukhopadhyay et al. 1989, The Biochemical Journal, 264, 517-525.). Treatment of the parasite with trypsin abolishes 75-90% of this [3H]heparin-binding activity. When trypsinized promastigotes were resuspended in fresh culture medium in the absence and presence of cycloheximide (10 micrograms/ml), approximately 25-30% of the original heparin-binding capacity was restored within 1 hr, indicating that recruitment of receptors from an internal pool occurred without de novo protein synthesis. Scatchard analysis of the regenerated receptor revealed that the number of regenerated binding sites per cell was 2.3 x 10(5); these sites have a binding affinity of 6.7 x 10(-7) M. Like the native heparin receptors on the surface of freshly isolated cells, the receptors recruited after trypsinization are also highly specific for heparin, as a 25-fold excess of four other glycosaminoglycans displaced less than 10% of bound [3H]heparin from the trypsinized cells. The structural requirements of the ligand heparin, namely the number of monosaccharide units and degree of sulfation, were compared for both the native and regenerated receptor: for both receptors, oversulfated polysaccharide heparin fragments of at least six to eight sugar residues were most efficient at displacing [3H]heparin. The concentrations of oligosaccharide fragments required to displace 50% of [3H]heparin were 0.32 and 0.035 microM for the hexa- and octasaccharides, respectively. Colloidal gold-labeled heparin was bound to promastigotes and visualized by electron microscopy. This analysis revealed that the heparin bound almost exclusively to the flagella of control cells (not subjected to trypsin) and those which had regenerated receptor after trypsinization. The physiological significance of this heparin-binding activity on the surface of promastigotes is discussed.

Use of 4-heptylumbelliferyl-beta-D-glucoside to identify Gaucher's disease heterozygotes

Three fluorometric beta-glucosidase assays were compared for their ability to identify Gaucher's disease heterozygotes, using leukocytes as the source of enzyme: the pH 5.5-taurocholate assay of Peters et al.; the conduritol B epoxide dependent variation of that assay; and the newly developed method described herein. While the first two procedures utilize the standard substrate 4-methylumbelliferyl-beta-D-glucopyranoside to estimate beta-glucosidase activity, the new assay uses 4-heptylumbelliferyl-beta-D-glucoside as (C7UGlc) substrate. Use of this substrate enhances the specificity of the method for lysosomal glucocerebrosidase, thereby minimizing the contribution of the nonspecific cytosolic beta-glucosidase to estimates of substrate hydrolysis. Using Student's t test for the three assays examined, the C7UGlc assay procedure was determined to have the lowest p value (p less than 0.001) and highest t value (t = 4.95) for the discrimination between the mean glucocerebrosidase value of control and obligate Gaucher heterozygote samples. The high reliability and simplicity of the C7UGlc assay lends adequate reason to favor this assay for regular clinical diagnosis of Gaucher heterozygotes.