Neohyadesia microtricha (Acari: Astigmata: Algophagidae): a new species from the sub-Antarctic

The sub-antarctic mite genus Neohyadesia (Acari: Astigmata) is known from two described taxa: N. signyi from Signy Island (South Orkney Islands, South Atlantic Province), and a subspecies, N. s. punctulata from Ile Kerguelen (South Indian Province). This paper describes a second species distinguishable by, in particular, cuticular microtrichae covering the dorsal surface. The new species, N. microtricha sp. nov., has a similarly disjunct sub-antarctic distribution, occurring on both Marion (SIP) and South Georgia (SAP) islands. A systematic synopsis of the sub-antarctic algophagine mites is given. Accepted: 30 June 2000     

Aquaglyceroporins: Generalized metalloid channels

Background

Aquaporins (AQPs), members of a superfamily of transmembrane channel proteins, are ubiquitous in all domains of life. They fall into a number of branches that can be functionally categorized into two major sub-groups: i) orthodox aquaporins, which are water-specific channels, and ii) aquaglyceroporins, which allow the transport of water, non-polar solutes, such as urea or glycerol, the reactive oxygen species hydrogen peroxide, and gases such as ammonia, carbon dioxide and nitric oxide and, as described in this review, metalloids.

Scope of review

This review summarizes the key findings that AQP channels conduct bidirectional movement of metalloids into and out of cells.

Major conclusions

As(OH)₃ and Sb(OH)₃ behave as inorganic molecular mimics of glycerol, a property that allows their passage through AQP channels. Plant AQPs also allow the passage of boron and silicon as their hydroxyacids, boric acid (B(OH)₃) and orthosilicic acid (Si(OH)₄), respectively. Genetic analysis suggests that germanic acid (GeO₂) is also a substrate. While As(III), Sb(III) and Ge(IV) are toxic metalloids, borate (B(III)) and silicate (Si(IV)) are essential elements in higher plants.

General significance

The uptake of environmental metalloids by aquaporins provides an understanding of (i) how toxic elements such as arsenic enter the food chain; (ii) the delivery of arsenic and antimony containing drugs in the treatment of certain forms of leukemia and chemotherapy of diseases caused by pathogenic protozoa; and (iii) the possibility that food plants such as rice could be made safer by genetically modifying them to exclude arsenic while still accumulating boron and silicon. This article is part of a Special Issue entitled Aquaporins.     

Effects of three global change drivers on terrestrial C:N:P stoichiometry: a global synthesis

Over the last few decades, there has been an increasing number of controlled‐manipulative experiments to investigate how plants and soils might respond to global change. These experiments typically examined the effects of each of three global change drivers [i.e., nitrogen (N) deposition, warming, and elevated CO₂] on primary productivity and on the biogeochemistry of carbon (C), N, and phosphorus (P) across different terrestrial ecosystems. Here, we capitalize on this large amount of information by performing a comprehensive meta‐analysis (>2000 case studies worldwide) to address how C:N:P stoichiometry of plants, soils, and soil microbial biomass might respond to individual vs. combined effects of the three global change drivers. Our results show that (i) individual effects of N addition and elevated CO₂ on C:N:P stoichiometry are stronger than warming, (ii) combined effects of pairs of global change drivers (e.g., N addition + elevated CO₂, warming + elevated CO₂) on C:N:P stoichiometry were generally weaker than the individual effects of each of these drivers, (iii) additive interactions (i.e., when combined effects are equal to or not significantly different from the sum of individual effects) were more common than synergistic or antagonistic interactions, (iv) C:N:P stoichiometry of soil and soil microbial biomass shows high homeostasis under global change manipulations, and (v) C:N:P responses to global change are strongly affected by ecosystem type, local climate, and experimental conditions. Our study is one of the first to compare individual vs. combined effects of the three global change drivers on terrestrial C:N:P ratios using a large set of data. To further improve our understanding of how ecosystems might respond to future global change, long‐term ecosystem‐scale studies testing multifactor effects on plants and soils are urgently required across different world regions.     

The first-stage zoeas of Carpilius convexus (Forskal, 1775) and Carpilius maculatus (Linnaeus, 1758) (Crustacea: Decapoda: Brachyura: Xanthoidea: Carpiliidae): an example of heterochrony

The first-stage zoeas of Carpilius convexus (Forskål,1775) and Carpilius maculatus (Linnaeus, 1758) are describedand fully illustrated. Both these Indo-West Pacific speciesexhibited a unique xanthoidean character for the basis of thesecond maxilliped, which possesses five (arranged 1,1,1,2) setaeinstead of the expected four (arranged 1,1,1,1). A comparisonwith the zoeal stages of Carpilius corallinus (Herbst, 1783)as reported by Laughlin et al. (Laughlin et al., 1983) revealedmarked differences including the possession of carapace lateralspines (v. absent in C. convexus only), the subterminal setationof the distal maxillule endopod segment with two subterminalsetae (versus one subterminal seta in Indo-West Pacific species),the terminal setation of the distal maxillule endopod segmentwith four setae (versus three setae in C. convexus only), twolateral spines on the telson (versus three in Indo-West Pacificspecies) and the number of zoeal stages. The first-stage zoeasof the two Indo-West Pacific species appear to have hatchedin a more advanced state of development than those of C. corallinus,and the expression of a number of characters has been accelerated(early onset). In fact, the zoeal stages of both Indo-West Pacificspecies and carpiliid species appear to be abbreviated becausethe first zoeas are considered to be equivalent to the third-stagezoeas of C. corallinus.     

Revision of Tegyrius (Coleoptera: Chrysomelidae: Galerucinae: Alticini), with descriptions of eight new species

The flea beetle genus Tegyrius Jacoby, 1887 (Coleoptera: Chrysomelidae) associated with Piperaceae is revised. Eight new species, namely Tegyrius agasthyai sp. nov. , Tegyrius dalei sp. nov. , Tegyrius nigrotibialis sp. nov. , Tegyrius pucetibialis sp. nov. , Tegyrius radhikae sp. nov. , and Tegyrius tippui sp. nov. , from India, and Tegyrius anupama sp. nov. and Tegyrius buddhai sp. nov. , from Sri Lanka, are described and illustrated. Key to species and host plant information are also provided. Tegyrius piceus Kimoto, 2001 is transferred to Longitarsus Latreille, 1829 (new combination); Tegyrius antennatus ( Medvedev, 2001 ), Tegyrius bicolor ( Medvedev, 2001 ) (both earlier Lankaphthona), and Tegyrius keralaensis ( Doeberl, 2003 ) (earlier Ogloblinia) are proposed as new combinations.     

Phylogeny of the tribe Sciophilini (Diptera: Mycetophilidae: Sciophilinae)

The monophyly and phylogenetic relationships within the species rich Sciophilini (Diptera: Mycetophilidae) were analysed, based on 96 adult morphological characters. The cladistic analysis included 80 Sciophilini exemplar species (representing all but 1 of the 36 genera placed previously in the Sciophilini) and 11 outgroup taxa of other mycetophilid tribes. The monophyly of Sciophilini was supported in the parsimony analysis by four synapomorphies. The tribe now contains 34 genera: Acnemia Winnertz, Acomoptera Vockeroth, Adicroneura Vockeroth, Afrocnemia Matile, Allocotocera Mik, Anaclileia Meunier, Aneura Marshall, Austrosciophila Tonnoir, Azana Walker, Baeopterogyna Vockeroth, Cluzobra Edwards, Drepanocercus Vockeroth, Duretophragma Borkent gen.n. , Eudicrana Loew, Leptomorphus Curtis, Loicia Vockeroth, Megalopelma Enderlein, Monoclona Mik, Morganiella Tonnoir & Edwards, Neoallocotocera Tonnoir, Neoaphelomera Miller, Neotrizygia Tonnoir & Edwards, Neuratelia Rondani, Paramorganiella Tonnoir, Paratinia Mik, Paratrizygia Tonnoir, Parvicellula Marshall, Phthinia Winnertz, Polylepta Winnertz, Sciophila Meigen, Stenophragma Skuse, Tasmanina Tonnoir, Taxicnemis Tonnoir & Edwards, and Trizygia Skuse. Four genera placed previously in Sciophilini (Coelophthinia Edwards, Impleta Plassmann, Speolepta Edwards and Syntemna Winnertz) are transferred to the Gnoristini. Neoneurotelia Shinji and Neoparatinia Shinji are considered nomina dubia . Diagnoses are given for all genera in the tribe. Duretophragma gen.n. is described for the following species (all of which are comb.n. ): Duretophragma andina (Duret), Duretophragma argentina (Duret), Duretophragma glabanum (Johannsen), Duretophragma fusca (Edwards), Duretophragma humeralis (Edwards), Duretophragma intermedia (Edwards), Duretophragma longifurcata (Freeman) (type species), Duretophragma morigenea (Edwards), Duretophragma naumanni (Duret), Duretophragma nigricauda (Edwards), Duretophragma obscura (Duret), Duretophragma ochracea (Freeman), Duretophragma pleuralis (Edwards) and Duretophragma similis (Johannsen). Other new generic combinations include: Trizygia albidens (Oliveira & Amorim) comb.n. , Trizygia alvesi (Oliveira & Amorim) comb.n. , Trizygia balbi (Oliveira & Amorim) comb.n. , Trizygia camargoi (Oliveira & Amorim) comb.n. and Afrocnemia stellamicans (Chandler) comb.n .     

Areography of the genus Dendroctonus (Coleoptera: Curculionidae: Scolytinae) in Mexico

Objective To analyse whether the geographical ranges of Dendroctonus species are (1) associated with factors such as host species or elevation, and (2) in agreement with Halffter's Nearctic distribution pattern. (3) To identify and discuss the factors that are likely to act as barriers to the genus’ geographical distribution. (4) To explore whether there is an association between the size of the geographical ranges of Dendroctonus species and the number of Pinus host species used by each of them, and (5) to assess if these host species are most common at the elevations preferred by the individual Dendroctonus species. Site Mexico. Methods Records of 12 species of Dendroctonus were gathered from entomological collections in Mexico. Distribution ranges were defined by using the propinquity method ( Rapoport, 1975a ). Analysed parameters were: (1) geographical distribution of single species, (2) overlapping of species ranges, (3) disjunction patterns and barriers by means of isoprobabilistic lines, based on the morphotectonic subdivision of Mexico ( Ferrusquía‐Villafranca, 1998 ), (4) spatial variation in species richness with respect to latitude and altitude, (5) size of geographical ranges, and (6) host species for each Dendroctonus species. A correlation was determined between area size and number of pine host species. Results The species ranges varied in shape and size. Geographical ranges tend to be discontinuous in shape. Composite patterns showed that disjunctions among ranges do not closely follow Mexico's morphotectonic subdivision. There are repeated discontinuities among individual distributions, which define five areas: (1) Baja California Peninsula, (2) Sierra Madre Occidental (SMOC), (3) northern Sierra Madre Oriental (SMOR), (4) Sierra Madre de Chiapas, and (5) SMOR + Faja Volcanica Transmexicana (FVT) + Sierra Madre del Sur. The isoprobabilistic lines confirm that the inner part of SMOC provides an optimal environment for the genus, and the FVT province constitutes the broader corridor for it in the country. Richness does not directly decrease or increase with latitude. Richness behaviour of the insect is not associated with that of its host. Elevation distributions showed that most Dendroctonus species move within broad margins of tolerance and species richness is concentrated in the montane interval. Dendroctonus attack 24 of the 47 Pinus species distributed in Mexico. Preferred pine species belong predominantly to Leiophyllae, Ponderosae and Oocarpae subsections. The Spearman rank correlation between area size and number of pine host species was not significant. Dendroctonus clearly belongs to a Nearctic distribution pattern (sensu Halffter, 1987 ). Main conclusions Dendroctonus is present in all montane systems of Mexico and its species coexist within a high geographical sympatry. Overlapping of species distribution appears to be the result of two elements – generalized polyphagy inside Pinus and a wide elevation tolerance within mountainous environments. This behaviour, linked to a high vagility, has allowed the genus Dendroctonus to expand its distribution across Mexico and to employ mountainous systems as corridors separated by barriers that exert a low selective filter effect.     

Walker Evans: Florida

Six Views of a Greek Village Everyday is not a Feast Day (1980, color, 110 minutes; video sale, $150) Thread of the Needle (1982, color, 22 minutes; video sale, $50) Let's Get Married! (1985, color, 35 minutes; video sale, $60) My Family and Me (1986, color, 65 minutes; video sale, $100) A Hard Life (1988, color, 55 minutes; video sale, $90) Charcoal‐Makers (1990, color, 30 minutes; video sale, $55) Filmmaker‐anthropologist: Colette Piault. All films available in 16mm, 1/2‐in. video. Distributed by Les Films du Quotidien, 5 rue des Saints‐Pères, 75006 Paris, France. Tel: 1–42 60 25 76; fax: 1–42 61 67 92); or Dr. Peter Allen, 98 Transit Street, Providence, R.I. 02906 (Tel: 401/274–2397; fax: 401/456–8379).

The Nehru Dynasty Life and Death of a Dynasty Produced by Anne and Robert Drew; narrated by Cliff Robertson. 1991, 90 minutes, color and black‐and‐white, 1/2” videotape, narration in English. Distributor: Direct Cinema Limited, P.O. Box 10003, Santa Monica, CA, 90410. Tel: (800)525–0000; Fax: (313)396–3233. Institutional sale, $195.00; rental $85.00.     

A new species of Gracixalus (Amphibia: Anura: Rhacophoridae) from northern Vietnam

We describe a new species of small tree frog from northern Vietnam based on morphological differences and molecular divergence. Gracixalus waza sp. nov. is distinguishable from its congeners and other small rhacophorid species on the basis of a combination of the following characters: (1) size small (snout-vent length of males 27.1–32.9 mm, of females 37.6 mm); (2) head as wide as or wider than long; (3) vomerine teeth absent; (4) snout rounded and long (16–18 % of the snout-vent length); (5) spines on upper eyelid absent; (6) tibiotarsal projection absent; (7) dorsal skin smooth; (8) dermal fringes on forearm and tarsus absent; (9) dorsal surface of head and body greyish-green to moss-green with dark brown pattern forming an inverse Y marking; and (10) throat and chest with dark marbling. Our molecular data showed that the new species is nested in the same group with Gracixalus jinxiuensis sensu lato.     

Thematic Review Series: Lysophospholipids and their Receptors: Novel lysophosphoplipid receptors: their structure and function

It is now accepted that lysophospholipids (LysoGPs) have a wide variety of functions as lipid mediators that are exerted through G protein-coupled receptors (GPCRs) specific to each lysophospholipid. While the roles of some LysoGPs, such as lysophosphatidic acid and sphingosine 1-phosphate, have been thoroughly examined, little is known about the roles of several other LysoGPs, such as lysophosphatidylserine (LysoPS), lysophosphatidylthreonine, lysophosphatidylethanolamine, lysophosphatidylinositol (LPI), and lysophosphatidylglycerol. Recently, a GPCR was found for LPI (GPR55) and three GPCRs (GPR34/LPS₁, P2Y10/LPS₂, and GPR174/LPS₃) were found for LysoPS. In this review, we focus on these newly identified GPCRs and summarize the actions of LysoPS and LPI as lipid mediators.     

Parasitoids ofPlutella xylostella (Lep.: Plutellidae) in South Africa: An annotated list

Larvae and pupae of diamondback moth,Plutella xylostella (L.) (Lepidoptera: Plutellidae), were collected weekly for two years on unsprayed cabbage plots. Samples were taken to the laboratory and parasitoids that emerged were identified and their incidence determined. Parasitoids were active throughout the year and parasitism was high (reaching 90–100%) except in the winter months of June–August when it was low. Twenty one species were reared: the egg-larval parasitoidsChelonus curvimaculatus Cameron and Chelonus sp. (Braconidae); the larval parasitoidsApanteles eriophyes Nixon,Cotesia plutellae (Kurdjumov),Habrobracon brevicornis (Wesmael) (Braconidae) andPeribaea sp. (Tachinidae); the larvalpupal parasitoidsDiadegma sp.,Itoplectis sp. (Ichneumonidae) andOomyzus sokolowskii (Kurdjumov) (Eulophidae); the pupal parasitoidsBrachymeria sp.,Hockeria sp. (Chalcididae),Diadromus collaris Gravenhorst (Ichneumonidae) andTetrastichus howardi (Olliff) (Eulophidae); and the hyperparasitoidsAphanogmus fijiensis (Ferrière) (Ceraphronidae),Brachymeria sp.,Hockeria sp.Proconura sp. (Chalcididae),Mesochorus sp. (Ichneumonidae),Pteromalus sp. (Pteromalidae),Eurytoma sp. (Eurytomidae) andTetrastichus sp. (Eulophidae).     

Further new species of the plant bug genus Campylomma Reuter from the Oriental Region (Heteroptera: Miridae: Phylinae: Nasocorini)

The fauna of the nasocorine plant bug genus Campylomma Reuter from the Oriental Region, including subtropical Japanese Ryukyu Islands (Okinawa Island of Southwest Islands-group) and Taiwan is updated. Three new species are herein described, C. astica n. sp. (from Okinawa and Taoyuan, Taiwan), C. hibiscicola n. sp. (Bangkok, Thailand) and C. nanrenana n. sp. (Pingtung, Taiwan). Of these, C. astica and C. hibiscicola, were observed to have cryptic habitat-preference, inhabiting bracts, stipules or flower buds of the sea (or coastal) hibiscus, Hibiscus tiliaceus (L.) (Malvaceae), planted for landscaping at urbanized zones. An updated checklist of the 22 Oriental Campylomma species is provided.     

Trichospilus pupivorus (Hymenoptera: Eulophidae): first report of parasitism on Thagona tibialis (Lepidoptera: Lymantriidae) in Brazil

We report the occurrence of Trichospilus pupivorus Ferrière, 1930 (Hymenoptera: Eulophidae) parasitizing pupae of Thagona tibialis Walker, 1855 (Lepidoptera: Lymantriidae) collected on Terminalia catappa L. (Combretaceae) tree in Viçosa, Minas Gerais, Brazil. Fifty to 75 parasitoids emerged from three pupae of Th. tibialis. This is the first record of Tr. pupivorus for the American continent and a new host record.

Relatamos a ocorrência de Trichospilus pupivorus Ferrière, 1930 (Hymenoptera: Eulophidae) parasitando pupas de Thagona tibialis Walker, 1855 (Lepidoptera: Lymantriidae) coletadas em uma árvore de Terminalia catappa L. (Combretaceae) em Viçosa, Minas Gerais, Brasil. Cinqüenta a 75 parasitóides emergiram de três pupas de Th. tibialis. Este é o primeiro relato de Tr. pupivorus no continente americano como também um hospedeiro novo.     

Phylogeny of the treehoppers (Insecta: Hemiptera: Membracidae): evidence from two nuclear genes

We present a molecular systematic investigation of relationships among family-group taxa of Membracidae, comprising nearly 3.5 kb of nucleotide sequence data from the nuclear genes elongation factor-1alpha (EF-1alpha: 958 bp) and 28S ribosomal DNA (28S rDNA: 2363 bp); data partitions are analyzed separately and in combination for 79 taxa. Analysis of the combined sequence data provided a better-resolved and more robust hypothesis of membracid phylogeny than did separate analyses of the individual genes. Results support the monophyly of the family Membracidae and indicate the presence of two major lineages (Centrotinae + Stegaspidinae + Centrodontinae and Darninae + Membracinae + Smiliinae). Within Membracidae, molecular data support the following assertions: (1) the previously unplaced genera Antillotolania and Deiroderes form a monophyletic group with Microcentrini; (2) Centrodontini and Nessorhinini are monophyletic clades that arise independently from within the Centrotinae; (3) Centrotinae is paraphyletic with respect to Centrodontinae; (4) the subfamily Membracinae is monophyletic and possibly allied with the darnine tribe Cymbomorphini; (5) the subfamily Darninae is paraphyletic; (6) the subfamily Smiliinae is paraphyletic, with molecular evidence indicating the exclusion of Micrutalini and perhaps Acutalini and Ceresini; and (7) Membracidae arose and diversified in the New World with multiple subsequent colonizations of the Old World. Our phylogenetic results suggest that morphology-based classifications of the Membracidae need to be reevaluated in light of emerging molecular evidence.     

Revision and phylogenetic analysis of the New World genus Neoclypeodytes Young (Coleoptera: Dytiscidae: Hydroporinae: Bidessini)

The western North American and northern Central American genus Neoclypeodytes Young is revised. Twenty‐five valid species are recognized in the genus. One additional name, N. luctuosus (Guignot) is treated as species of uncertain status. Eleven new species are described: N. amybethae, N. anasinus, N. astrapus, N. challeti, N. edithae, N. haroldi, N. megalus, N. nanus, N. roughleyi, N. similis and N. tumulus. Six new synonymies are established: N. centralis (Sharp) = N. cinctellus (LeConte); N. substriatus (Sharp) = N. discedens (Sharp); N. americanus (Guignot), N. decoratus (Fall) and N. quadrisignatus (Sharp) = N. fryii (Clark); and N. rugulosus (Guignot) = N. obesus (Sharp). Lectotypes are designated for N. curtulus (Sharp), N. discedens, N. discretus (Sharp), N. lynceus (Sharp), N. obesus, N. ornatellus (Fall), N. pictodes (Sharp), N. plicipennis (Crotch), N. quadrinotatus (Sharp), N. quadripustulatus, N. quadrisignatus and N. substriatus. A key is provided for the known species of Neoclypeodytes. Distribution maps, illustrations of important morphological features and natural history notes are provided for each species. A single possible synapomorphy was found supporting the monophyly of Neoclypeodytes, a pattern of two maculae on each elytron. The perplexing and unresolved relationships of Neoclypeodytes to other bidessine genera are discussed. A cladistic analysis using twenty‐two characters of adult morphology is presented for twenty‐five species of Neoclypeodytes, with Uvarus lacustris (Say) and Liodessus affinis (Say) as outgroup taxa (rooted at U. lacustris). A single most parsimonious cladogram was obtained.     

Bioengineering report: Fouling biofilm development: A process analysis

Biofilm development at a surface is the net result of several physical, chemical, and microbial processes including the following: (1)transport of dissolved and particulate matter from the bulk fluid to the surface; (2) firm microbial cell attachment to the surface; (3) microbial transformations (growth, reproduction, etc.) within the biofilm resulting in production of organic matter; (4) partial detachment of the biofilm due primarily to fluid shear stress. This report presents a framework for analyzing the interrelated processes contributing to biofilm development. Some of the available rate and composition data are presented so that the relative process rates can be compared.     

Trioza hopeae sp. nov. (Hemiptera: Triozidae): A pest on Hopea odorata (Malvales: Dipterocarpaceae) in Vietnam

Trioza hopeae sp. nov. is described and illustrated from Vietnam. Trioza hopeae develops on Hopea odorata, a valuable timber tree on which it causes serious damage by inducing leaf galls. The new species is closely related to Trioza minuta (Mathur) comb. nov. (from Ceropsylla Riley), an Indian species associated with Shorea robusta. Differences between the two species are discussed. Another five Indian species are transferred here from Ceropsylla to Trioza Foerster as T. ferruginea ( Mathur, 1975 ) comb. nov., T. fulvida ( Mathur, 1975 ) comb. nov., T. indica ( Kandasamy, 1986 ) comb. nov., T. longivenata ( Kandasamy, 1986 ) comb. nov., and T. parvus ( Kandasamy, 1986 ) comb. nov.     

The genus Coperonus Wilson, 1989 (Crustacea: Isopoda: Asellota: Munnopsidae)

This paper presents a revision of the natatory isopod genus Coperonus (Munnopsidae, Lipomerinae). A key to identify all seven known species of the genus is provided. Four new species are described and Coperonus frigida (Vanhöffen, 1914) is redescribed on the basis of the type material. The biogeography of Coperonus is described.
In dieser Arbeit wird die Gattung Coperonus (Munnopsidae, Lipomerinae), deren Vertreter sich durch gute Schwimmfähigkeit auszeichnen, revidiert. Ein Bestimmungsschlüssel für alle sieben bisher bekannten Arten ist in der Arbeit enthalten. Es werden vier neue Arten beschrieben und Coperonus frigida (Vanhöffen, 1914) wird anhand des Typenmaterials nachbeschrieben. Auβerdem wird in der Arbeit die Biogeographie von Coperonus dargestellt.     

ArsP: a methylarsenite efflux permease

Trivalent organoarsenic compounds are far more toxic than either pentavalent organoarsenicals or inorganic arsenite. Many microbes methylate inorganic arsenite (As(III)) to more toxic and carcinogenic methylarsenite (MAs(III)). Additionally, monosodium methylarsenate (MSMA or MAs(V)) has been used widely as an herbicide and is reduced by microbial communities to MAs(III). Roxarsone (3‐nitro‐4‐hydroxybenzenearsonic acid) is a pentavalent aromatic arsenical that is used as antimicrobial growth promoter for poultry and swine, and its active form is the trivalent species Rox(III). A bacterial permease, ArsP, from Campylobacter jejuni, was recently shown to confer resistance to roxarsone. In this study, C. jejuni arsP was expressed in Escherichia coli and shown to confer resistance to MAs(III) and Rox(III) but not to inorganic As(III) or pentavalent organoarsenicals. Cells of E. coli expressing arsP did not accumulate trivalent organoarsenicals. Everted membrane vesicles from those cells accumulated MAs(III) > Rox(III) with energy supplied by NADH oxidation, reflecting efflux from cells. The vesicles did not transport As(III), MAs(V) or pentavalent roxarsone. Mutation or modification of the two conserved cysteine residues resulted in loss of transport activity, suggesting that they play a role in ArsP function. Thus, ArsP is the first identified efflux system specific for trivalent organoarsenicals.