4×10 Gbit/s bidirectional transmission over 2 km of conventional graded-index OM1 multimode fiber using mode group division multiplexing.

We demonstrate 4 × 10 Gbit/s error-free bidirectional transmission over 2 km of conventional OM1 graded-index multimode fiber using OOK modulation and direct detection. We also perform field transmission to show reach and capacity boosts on legacy multimode infrastructure. Such transmission is enabled by selective mode group division multiplexing, based on multi-plane light conversion over 4 mode groups of the multimode fiber.

Spread of parasites transported with their hosts: case study of two species of cattle tick.

Like all parasites, ticks can be spread easily along with their hosts. Ticks are obligate parasites of vertebrates, to which they attach themselves for varying periods of time, and are well-adapted to this mode of transport. Once the transport stage is complete and they have detached at destination, they are also able to wait several months for the arrival of a new host on which they will continue their life cycle. This leads to the establishment of a secondary tick population. Two tropical cattle tick species, Rhipicephalus microplus and Amblyomma variegatum, have perfected this strategy of colonisation and occupation of favourable zones. Rhipicephalus microplus, which originated from South and Southeast Asia, is highly specific for ungulates, and thanks to cattle movements it has spread throughout the tropical belt, apart from the remotest areas. Amblyomma variegatum, which originated in Africa, was transported to Madagascar and the Mascarene Islands, as well as to the West Indies, during the time of the Atlantic triangular trade. These two ticks are vectors of particularly serious cattle diseases: babesiosis and anaplasmosis in the case of R. microplus, and heartwater (cowdriosis) in the case of A. variegatum. Anticipated climate changes are likely to modify the potential geographical range of these two parasite species and numerous others. Even now there are still many areas of the Americas, Asia and Oceania into which A. variegatum has not yet spread, but which it would find favourable. It could be spread not only by the transport of cattle, but also by the migration of some of its other hosts, such as birds. Surveillance--and know-how--is needed to identify these parasites when they first appear and to rapidly contain new outbreaks. Efforts should be made to raise the awareness of livestock professionals about the risks of transporting cattle. Regulations should be implemented and precautions taken to avoid such artificial expansion of the range of ticks and the diseases they transmit.

Population genetic structure of wild and farmed rusa deer (Cervus timorensis russa) in New-Caledonia inferred from polymorphic microsatellite loci.

Historical records indicate that 12 rusa deer (Cervus timorensis russa) were introduced in New-Caledonia during the 1870s. We used eight polymorphic microsatellite DNA loci to assess the genetic differentiation and diversity of farmed and wild deer populations. Past genetic bottlenecks were detected in both sub-populations, although higher genetic diversity was maintained in farmed populations, probably due to the regular introduction of reproducers from wild populations and from other farms. The genetic structure of farmed and wild populations differed significantly. There was a significant isolation by distance for wild populations, whereas farmed populations were significantly differentiated between farms independently from their geographical proximity. Wild rusa deer consisted of small populations (with effective population sizes ranging between 7 and 19 individuals depending on the methods used), with a low parent-offspring dispersion range (0.20-2.02 km). Genetic tools and direct observations provided congruent estimates of dispersion and population sizes. We discuss the relevance of our results for management purposes.

Diagnosis of amitraz resistance in Boophilus microplus in New Caledonia with the modified Larval Packet Test.

The tick Boophilus microplus represents a serious pathological constraint to livestock production in New Caledonia. Cattle ticks are controlled by chemical application of two acaricides that are currently used in New Caledonia; deltamethrin is used at 46% of the cattle production facilities and amitraz at the remaining 54% premises where resistance to deltamethrin has been identified. In 2003, a modified Larval Packet Test (LPT) was used to conduct a survey for amitraz resistance. Ticks were collected from 29 farms, including farms using deltamethrin (n=8) or amitraz (n=21). Of eighteen different tick populations, sixteen populations were defined susceptible to amitraz and two populations were considered amitraz-resistant. This is the first report of populations of B. microplus being resistant to amitraz, using the modified LPT in New Caledonia. A thorough survey of tick susceptibility to amitraz in cattle farms of the country should be conducted to assess the presence of amitraz-resistant populations. The emergence of amitraz resistance so soon after its introduction has some important implications for the strategy and organisation of tick control in New Caledonia, and this paper discusses some of the urgent actions that should be undertaken.

Zebrafish keratin 8 is expressed at high levels in the epidermis of regenerating caudal fin.

Cytokeratins are structural proteins of the intermediate filament family and are mainly expressed in epithelial cells. In several vertebrates it has been shown that keratin 8 is expressed in simple epithelial tissues, some non-epithelial tissue and in hyper-proliferative tissues during development and tumor transformation. We previously cloned and characterised the zebrafish (Danio rerio) homologous cytokeratin 8 cDNA (zfk8) which was described as an epidermal marker during zebrafish development. It has been found that the zfk8 gene is normally expressed in simple epithelia in embryonic and mature zebrafish. Using whole-mount in situ hybridisation, we show in this report that expression of zfk8 is tightly linked to the regeneration of caudal fin and exclusively observed in epidermal cells. It is strongly expressed in the epidermis overlaying the inter-rays zone of regenerating caudal fin. Our results indicate that in zebrafish, cytokeratin 8 is a suitable epidermal marker during regeneration.

In vivo synthesis and processing of rat hypothalamic prosomatostatin.

The in vivo incorporation of [3H]phenylalanine into an apparent 15 kDa prosomatostatin was observed in the hypothalamus of rats injected with the labeled amino acid in the third ventricle. Precursor-product relationships were established between this newly synthesized material and both somatostatin-28 and -14.

Evidence for a leukotriene A4 hydrolase in Xenopus laevis skin exudate.

Leukotriene A4 hydrolase is a cytosolic metalloenzyme of the arachidonic acid biosynthetic pathway responsible for leukotriene A4 conversion into leukotriene B4. In addition to its epoxide hydrolase properties, this enzyme exhibits an aminopeptidase activity which was used as an assay to monitor the purification of a novel form of leukotriene A4 hydrolase from Xenopus laevis skin exudate. This 70 kDa, secreted, form of leukotriene A4 hydrolase was identified by immunochemical cross-reactivity with anti-human leukotriene A4 hydrolase antibodies and by its capacity to convert leukotriene A4 into leukotriene B4. Moreover this enzyme produced a second metabolite which could be the leukotriene B4 isomer 5S,12R-dihydroxy-6,10-trans-8,14-4-cis-eicosatetraenoic acid, previously shown by Strömberg et al. (Eur.J. Biochem. 238 (1996) 599-605) to be formed by incubation of the leukotriene A4 with amphibian tissue extracts. Partial amino acid sequencing of peptides generated by endolysin C fragmentation of the purified enzyme confirmed the presence, in X. laevis skin secretions, of a related but distinct form of leukotriene A4 hydrolase which is likely to be responsible for the production of these eicosanoid metabolites of leukotriene A4.

COOH-terminally-extended processing forms of oxytocin in human ovary.

Human granulosa cells synthesize and secrete the oxytocin hormone. We have already shown that oxytocin-Gly, the last post-translational maturation intermediate of pro-hormone, is largely secreted by cultured granulosa cells deprived of ascorbate (Plevrakis et al. (1990) J. Endocrinol. 124, R5-R8). Using a combination of high performance liquid chromatography and radioimmunoassay, the oxytocin-like material present in human granulosa cell extracts, in follicular fluid, in cultured granulosa cell supernatants and in corpora lutea extracts was identified. We have demonstrated the presence of oxytocin-Gly, oxytocin-Gly-Lys and oxytocin-Gly-Lys-Arg, the same post-translational maturation intermediates as those we identified in bovine corpus luteum secretory granules. Thus we conclude that post-translational maturation of pro-oxytocin/neurophysin in human ovary proceeds by the same proteolytic events as those we described in bovine post-pituitary gland and corpus luteum.

Synthesis and processing of pro-ocytocin in bovine corpus luteum and granulosa cells.

Bovine corpus luteum is the site of intense production of pro-ocytocin-neurophysin mRNA at day 1 after estrus (Ivell et al. (1985) FEBS Lett. 190, 263-267) which is followed by apparent delayed production of ocytocin. Therefore it is a good model to study both the translational and post-translational production of this neuropeptide in non-hypothalamic tissues and its regulation. In order to assess if this mRNA is translated during the lag period we have analyzed the neurophysin-like species produced in this organ. As early as day 2 after estrus one neurophysin species (pI approximately 4.7) could be detected and was unequivocally identified as pro-ocytocin-neurophysin. In primary cultures of luteinizing granulosa cells, biosynthetic intermediates were characterized, i.e. ocytocin-Gly, ocytocin-Gly-Lys and ocytocin-Gly-Lys-Arg, whereas amidated, fully mature, ocytocin was undetectable. We conclude that translation of pro-ocytocin-neurophysin mRNA takes place soon after transcription and we propose that incomplete processing could be responsible for the low level of ocytocin in the early bovine corpus luteum.

Aminopeptidase-B in the rat testes: isolation, functional properties and cellular localization in the seminiferous tubules.

An aminopeptidase of the B-type, with an apparent M(r) 72,000 and pI = 4.9, was isolated from rat testes and characterized. The enzyme was able to remove only Arg and/or Lys residues from L-amino acid beta-naphthylamide derivatives and from the N-terminus of several peptides. No cleavage occurred in the case of Arg-Pro bonds as found in bradykinin and substance P. The enzyme was sensitive to cysteinyl reagents and to aminopeptidase inhibitors, such as bestatin, amastatin and arphamenines A and B. The aminopeptidase activity, tested with L-Arg beta-naphthylamide and with Arg0-Met-enkephalin as substrates, was inhibited by o-phenanthroline, and restored by Zn2+ suggesting its metallopeptidase character. The partial characterization of an aminopeptidase-B activity in rat brain cortex identified a protein which is biochemically and immunologically related to the testis enzyme. By immunohistochemistry, the aminopeptidase-B was found to be particularly abundant in the seminiferous tubules at late stages of spermatogenesis and was clearly detected in a restricted area of elongated spermatids. Remarkably, the enzyme was observed to concentrate massively in the residual bodies. Since this aminopeptidase-B was able in vitro to trim out N-terminal Arg and/or Lys residues from peptides mimicking processing intermediates, it is proposed that this enzyme may be involved in propeptide and proprotein processing mechanisms in the course of spermatid differentiation.

The role of Amblyomma variegatum in the transmission of heartwater with special reference to Guadeloupe.

Heartwater has been diagnosed in Guadeloupe, Marie-Galante, and Antigua; it induces important losses among goats and European or cross-bred cattle when local zebu creole are highly resistant to infection. Amblyomma variegatum is the vector of the disease in the Caribbean. The tick strain of Martinique, occurring in that island that has apparently been disease-free since 1948, has not lost its ability to experimentally transmit the disease. In Guadeloupe 97% of nymphs and nearly 100% of adults feed on cattle and goats. Some immature ticks (4.5%) feed on wildlife, including birds that may be involved in the spread of infected ticks. Only 1 to 4% of adult ticks are infected and only a proportion of infected ticks are really infective: 53%, 9%, and 50% of nymphs, males, and females, respectively. Nymphs play the major role in the transmission: they are more numerous than adults and engorge faster. Infected ticks have the same maximum longevity as noninfected ticks, that is, 18 months for nymphs and nearly 23 months for adults. Cowdria is not transmitted immediately after tick fixation but after a delay of 2-3 days for nymphs and 4 days for adults. The disease is more often fatal when transmitted by tick biting rather than by needle transmission. The daily infection rate that summarizes all the parameters is very low (0.14% and 0.20% for goats and cattle, respectively), resulting in an unstable epidemiological situation. The transmission of Cowdria by A. variegatum in Guadeloupe shows significant differences compared with the transmission by A. hebraeum in Africa.

Attempts to feed Amblyomma variegatum ticks on artificial membranes.

Feeding jars were used to feed nymphs of Amblyomma variegatum on blood of goats or cattle. Sterile blood was collected daily or weekly (kept at 4 degrees C or frozen until use), with addition either of heparin alone or of heparin and antibiotics/fungicide or of heparin, adenosine triphosphate and glutathione. Membranes were made of a thin (0.12-0.32 mm) film of silicone mastic. Blood in the jars was replaced twice a day, and reached a temperature of 39 degrees C in a waterbath before it became available to the ticks. Attachment of nymphs was stimulated by dropping on the membrane fresh goat hair and squamae collected close to prefed males, skin washing and natural pheromone extracts. Using these devices, attachment of nymphs is rapid and intense (68%). Their body mass when engorged and the molting success, were lower than that of naturally fed ticks. Furthermore, the proportion of engorging ticks was usually much less and the length of the blood meal was much longer than of naturally fed ticks. The best results were obtained with fresh goat blood or cattle blood with antibiotics. Further developments are needed before this method can be used routinely.

Effect of the association of cattle and rusa deer (Cervus timorensis russa) on populations of cattle ticks (Boophilus microplus).

The wild population of rusa deer (Cervus timorensis russa) in New Caledonia (South Pacific) is nearly as large as the cattle population. The cattle tick is widespread and occurs all year round. Opinions are divided on the role of deer in the biological cycle of the tick: i) Do they maintain a sustainable tick population that is secondarily available for cattle? ii) Do they decrease the infestation of the environment by collecting larvae on the pasture, but preventing their development to the engorged female stage? or iii) Do they contribute to both situations? An experiment was conducted in three groups of pastures, each seeded with 450 000 larvae/ha and allowed to be grazed only by cattle, only by deer, and by a mixed herd of deer and cattle (deer representing 30% of the biomass), at approximately the same stocking rate (470-510 kg/ha). After 15 months of exposure, the tick burden per weight unit of host was 42 ticks/kg for the steers-only herd and 0.01/kg for the deer-only herd. The steers in the "mixed group" harbored 7 times fewer ticks (6.2/kg) than the cattle-only group, and the deer in the "mixed group," 130 times more (1.3/kg) than the deer-only group. Five emergency acaricide treatments had to be applied in the cattle-only group, but none in the other groups. The long-term sustainability of a viable tick population on deer as well as the potential benefit resulting from the association of deer and susceptible cattle in the tick control of cattle are highlighted.

Successes and failures in the tropical bont tick eradication campaigns in the French antilles.

The Amblyomma variegatum eradication campaigns, based on three phases and a 5-year program, as in other islands of the Caribbean, started in the French Antilles in April 1994 with various financial inputs. The progress of the campaigns in the two islands of Guadeloupe and Martinique contrast sharply. Owing to a shortage and inadequacy of results with regard to the initial objectives, particularly in organization, communication efforts, cattle identification, and application of acaricides on livestock, the European Community which was the most important donor, did not support the Guadeloupean program in 1996 and 1997. This induced a deep crisis in the local sanitary organization, which has the responsibility for the execution of the project, and the almost total interruption of acaricide treatments in Guadeloupe and its dependencies (Marie-Galante, St Martin, Désirade). In Martinique on the contrary, a well-defined organization, communication strategy, and personnel training effort resulted in a generalized census of livestock owners. Identification of cattle increased dramatically in number and the systematic treatment of livestock started in satisfying conditions. It is too early to anticipate on the final result of the campaign, but it is clear that a longer period of time than previously planned, will be necessary to achieve the program. If this prolongation is accepted, it may allow Guadeloupe to take part again in the campaign, a condition absolutely necessary for its regional success.

Herbage density of third-stage larvae of goat strongyles during the dry season in Guadeloupe.

The objective of this study was to determine the main sources of variation in herbage densities of infective third stage larvae of goat strongyles during the marked dry season of 1994 in Guadeloupe (FWI). Herbage samples were collected for L3 density (LD) determination by an accurate method, 4 times at 4-week intervals in 58 paddocks of 21 farms spread out in five regions of the archipel of Guadeloupe. At the same time, FEC of each grazing animal and fecal culture for parasite genus determination according to sex and age were carried out. Stocking rate, dry matter content of soil, and daily climatic data were also recorded. An index of egg development in larvae (IEDL) was calculated as the ratio of LD to the eggs deposed during the 4th, 3rd, and 2nd weeks before sampling. Medians of LD in herbage were 3397, 1853, 1410, and 324 L3/kg DM for all parasites, Haemonchus, Trichostrongylus, and Oesophagostomum, respectively. Date of sampling, region, and irrigation practice in the northern windward region were the main sources of variation in LD and in frequency of each parasite. LD decreased as the dryness lasted, but it remained important (500 L3/kg DM) despite the drought. LD in windward regions were higher than in other regions. The region, the farm, and the paddock were the main sources of variation of IEDL. LD of each parasites were inversely correlated to global radiation recorded 1 to 3 weeks before herbage sampling, but no relation was found with rainfall data. Trichostrongylus frequency in L3 population increased as the dryness lasted. A dryness axis was extracted from environmental variables (climatic data, dry matter of soil, duration of dryness) by a multiple factorial procedure. LD and Haemonchus frequency in L3 population were inversely correlated to dryness axis (p < 0.01). In contrast, Trichostrongylus frequency was positively correlated to the dryness component.

Development of a computer model of the population dynamics of Amblyomma variegatum and simulations of eradication strategies for use in the Caribbean.

Control or eradication efforts should cover wide areas because of long-range migration potential of immature ticks attached to birds, such as cattle egrets. Careful follow-up inspections are also imperative. Simulation 1 shows how rapidly the population numbers may expand from small numbers, either introduced or missed. Simulation 4 indicates extending the treatment cycle beyond the residual effectiveness of the acaricide to save labor or funds would be false economy. The result could be to maintain the tick population indefinitely, with an accompanying increase in long-term control costs. Simulations 2 and 3 indicate that eradication is possible if response is prompt and the treatment cycle is less than the period of residual effectiveness of the acaricide used.

Potential impact of wildlife on the tropical bont tick eradication program in the Caribbean.

Wildlife are hosts for A. variegatum throughout its range in Africa, and have been demonstrated to serve as hosts for larvae and nymphs on several islands in the Caribbean. Studies conducted in the Caribbean have indicated that most larvae and nymphs and all adults of the tick feed on livestock; therefore, eradication can be approached through the treatment of livestock. However, since small numbers of animals such as the mongoose are infested with larvae and nymphs, these animals may represent a short-term alternative host system. Such infestations potentially could result in a presence of small numbers of ticks for up to 46 months after the onset of a treatment program and could serve as a source to reinfest livestock during the eradication process. Wildlife surveys have been conducted in St. Croix, Puerto Rico, Guadeloupe, and Antigua; but the host status of species present on other islands such as the white-tailed deer on St. Kitts has not been evaluated. As part of the eradication program, the species of wildlife present on each island and the association of these species with infested pastures should be determined. Surveys of wildlife can be used during the eradication to determine if wildlife are serving as an alternative host system. Cattle egrets may serve to disseminate the tick among islands in the region, and to areas outside the region. Cattle egrets have been shown to serve as hosts for the tick, and to move throughout the eastern Caribbean and to North America. The potential for interisland dissemination of ticks by cattle egrets, as well as by other means, substantiates the need for a region-wide eradication program.

Factors of variation of Amblyomma variegatum infestation on Creole cattle in Guadeloupe.

The level of infestation of "Creole" beef cattle of Guadeloupe by the tick Amblyomma variegatum was recorded during a long-term survey in an experimental farm: 61 steers and 83 cows were distributed in different lots according to sex and management. They grazed continuously either on irrigated Digitaria decumbens pastures or on dry native savannahs. Tick numbers as well as animal weights were registered monthly. Climatic data were also recorded. Different acaricide treatments were tested during the survey. But in order to minimize their effect in the data analysis, only tick counts over an average of 5 adult ticks per cattle were taken into account. The level of infestation is analyzed with respect to environmental factors (season, management) and individual factors (sex, weight, physiological stage, genetic effect). The effects of these factors are discussed with regard to alternative tick-control methods, such as the selection of resistant hosts.

Tick reference collection of the late Dr. P.C. Morel: a tool for tick taxonomists and veterinarians.

Host preference of ticks is an important, but still controversial, subject. Recent developments in molecular biology provide new opportunities to test some hypotheses about host preference in a given environment if appropriate specimens are available. Since the unique collection gathered by Dr. P.C. Morel could help achieve this goal, we present an overview of the samples available in his collection.

Tropical bont tick eradication campaign in the French Antilles. Current status.

The Amblyomma variegatum eradication campaign was officially started in April 1994 in Martinique and in Guadeloupe, including its dependencies of Marie Galante, Desirade and St Martin. A budget of $10.5 and $5.9 million for Guadeloupe and Martinique, respectively, was initially (1991) calculated and considered necessary to achieve the program. However, EEC, the most important donor, estimated that 75% only of this proposal was acceptable, on which it agrees to support a maximum of 50%. The balance had to be provided by French government, local political institutions, and animal owners. The current budget actualized in 1995 by veterinary authorities of Martinique and Guadeloupe is $7,200,000 and $9,900,000 respectively. The program will take 5 years: preparation (1 year), acaricide application (3 years), surveillance (1 year). During this first year, a pilot committee was established, and a project leader was designated for each island. Efforts were essentially oriented to organize the program in the field and to obtain funds from French and local counterparts. Funds allowed the recruitment and training of 19 new agents in Guadeloupe and 9 in Martinique, in addition to personnel already involved in the tick control program. Census of animal owners and identification of cattle started or were developed. Tenders were invited to provide vehicles and acaricides. For the latter, choices were made considering the prices and efficacy as well as funds available. Due to a limited budget and cost of pour-on formulations, pour-on acaricides will be used on a maximum of 30% of animals only. In order to investigate animal owners' reticences and the most appropriate media channels to establish a communication and a training program, a survey was conducted in Guadeloupe on a sample of 301 animal owners. The results are presented. In order to strengthen the chances of success of the campaign in the French islands, it is expected that a similar program will take place soon in infested neighboring islands.