A programmable environmental system for maintenance and observation of individually housed ticks

This paper describes an inexpensive, space-saving, and labor-efficient method for housing and making repeated observations of individual ticks held under specific photoperiodic, temperature, and humidity conditions. Using 96-well assay plates to house ticks, various developmental parameters, sex, survival, etc., of several thousand individual ticks can be recorded routinely in less than 1 hr. This design also permits more than 3,500 individual ticks to be maintained in 1 small (18.9-L) aquarium that serves as a humidity chamber. A small, unilluminated constant temperature incubator was converted inexpensively into a light and temperature programmable unit to contain the aquarium by adding a timing system, light fixture, and a second thermostat.     

A scheme of rabbit spermateleosis based upon electron microscopical observations

Summary Rabbit spermateleosis is subdivided into ten stages (A to J) based upon fine structure. Spherical spermatids in stages A to D correspond to the Golgi phase and the cap phase of Leblond and Clermont (1952a). Elongating spermatids in stage E through the first half of stage H correspond to the acrosome phase, and maturating spermatids in the second half of stage H through stage J correspond to the maturation phase. The development of the different organelles during each stage is described and put into a scheme of normal rabbit spermateleosis that can be used as a reference in experimental investigations of ultrastructural changes.This work was supported by grants from Anslaget för främjande av ograduerade forskares vetenskapliga verksamhet vid Veterinärhögskolan.     

A new method for radioautographic observation on isolated cells

Summary The procedure of a new method of radioautographic observation on isolated cells from the liver and the pancreas was described. Through this method binucleato cells are distinctly distinguished from mononucleate cells in radioautographs. Thus, the study on binuclearity in such organs from histochemical viewpoint has come to be carried out without difficulty.

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Zusammenfassung Eine neue Methode für radioautographische Beobachtung über die isolierten Zellen einiger Organe wurde dargestellt. Durch diese Methode kann man leicht zweikernigen Zellen von einkernigen in solchen Organen wie der Leber oder dem Pankreas, die häufig zweikernige Zellen haben, auf radioautographischen Präparaten unterscheiden. Dadurch kann man ohne Schwierigkeit über die Zweikernigkeit aus dem histochemischen Standpunkt studieren.

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With 5 Figures in the Text     

A novel neuropeptide-endocrine interaction controlling ecdysteroid production in ixodid ticks.

Ixodid (hard) ticks are blood-feeding arthropods that require a blood meal to complete each stage of development. However, the hormonal events coordinating aspects of feeding and development are only poorly understood. We have delineated a new neuropeptide-endocrine interaction in the adult tick, Amblyomma hebraeum, that stimulates the synthesis of the moulting hormones, the ecdysteroids. In adult female ticks, ecdysteroid synthesis could be demonstrated in integumental tissue incubated in vitro with a synganglial (central nervous system) extract, but not in its absence. Stimulation by the synganglial extract is both time- and dose-dependent, but is completely abolished by trypsin treatment, suggesting that the activity is due to a peptide/protein. Integumental tissue ecdysteroidogenesis is also stimulated by elevation of the cAMP concentration using forskolin and 3-isobutyl-l-methyl-xanthine, or by 8-bromo-cAMP. This suggests the involvement of at least a cAMP second messenger system in the neuropeptide-ecdysteroidogenesis axis, without precluding a role for other second messengers as well. Despite involving a quite different steroidogenic tissue, the foregoing system has some parallels with the known prothoracicotropic hormone (neuropeptide)-prothoracic gland endocrine axis of insects.     

New Minto virus: a new rhabdovirus from ticks in Alaska

Three strains of a virus were isolated from Haemaphysalis leporis-palustris (Packard) ticks removed from snowshoe hares (Lepus americanus Erxleben) in east central Alaska. We suggest that the virus be named New Minto for the location in which the ticks were collected. Prototype New Minto virus is sensitive to the action of sodium deoxycholate and kills suckling mice by the intracerebral but not intraperitoneal route; weaned mice do not die after intracerebral, intraperitoneal, or subcutaneous inoculation. The virus produces plaque in serially propagated Vero but not in primary Pekin duck embryo cells. By complement-fixation and neutralization tests New Minto is related to Sawgrass Virus, a hitherto ungrouped virus from Florida. The establishment of a Sawgrass group is suggested. In addition, Sawgrass virus was found by electron microscopy to belong to the Family Rhabdoviridae.     

A self-medicating applicator for control of ticks on deer

Abstract. A self-medicating applicator for killing ticks on deer and domestic ungulates by passive transfer of acaricides during feeding is described. The applicator consists of a barrel divided into a food bin (above) and a sealed self-contained acaricide reservoir (below) with a vertical, centrally-located ceramic column that extends from the reservoir into the food bin. Acaricide is drawn up the column from the sealed reservoir by absorption. Animals attracted to the food in the device acquire the acaricide during feeding when they contact the uppermost portion of the column.
White-tailed deer (Odocoileus virginianus) readily utilize the applicator in penned and natural conditions. In a field study, examination of hunter-killed deer demonstrated that animals from a treated site were infested with many fewer Ixodes scapularis (3.4 ± 1.1) than those from a control site (10.8 ± 3.0). Chromatographic analysis of hair samples revealed traces of permethrin on three of the four animals examined, suggesting use of applicators by these deer. In a study using penned goats {Capra hircus) infested with Amblyomma americanum ticks, treatment efficacy reached 86.4% within 4 days of exposure to the applicators. Visual observations confirmed that all animals used the applicators. Gas chromatographic analysis of goat hair samples indicated that permethrin was detectable on all of the treated animals exposed to the device.     

Interspecific differences in the movements of female ticks on reptiles.

Movements of females of two reptile ticks, Amblyomma limbatum and Aponomma hydrosauri were studied to determine whether the behaviour of the species on hosts was similar or different. Experiments were conducted to determine if the movement of females on hosts prior to mating was influenced by the delayed attachment of conspecific males. A field experiment was also undertaken to determine whether data obtained during laboratory experiments reflected the behaviour of females on hosts in the field. Both in laboratory and field experiments, a significantly greater proportion of Ap. hydrosauri females changed their site of attachment prior to mating. Individual Ap. hydrosauri females made significantly more positional changes than Amb. limbatum females. These interspecific differences occurred irrespective of the absence of conspecific males or presence of non-conspecific adults on hosts. These data may have important ecological implications in relation to the success of colonizing females at their parapatric boundary.     

A new genus of hard ticks in Cretaceous Burmese amber (Acari: Ixodida: Ixodidae)

A hard tick larva in Cretaceous Burmese amber is described as Cornupalpatum burmanicum n. g., n. sp. Diagnostic characters include a subcircular body with a marginal groove, 11 festoons, elongate four-segmented palpi with the fourth segment distinct and apical, the absence of an anal groove and eyes, and the presence of claws on palpal segment 3. The last character is unique for all members of the Ixodida, both fossil and extant. Aside from the palpal claws and marginal groove, features of the tick larva closely resemble those of members of the genus Aponomma Neumann 1899, considered one of the most primitive tick lineages today, whose hosts are primarily reptiles.     

A cysteine protease is critical for Babesia spp. transmission in Haemaphysalis ticks

Vector ticks possess a unique system that enables them to digest large amounts of host blood and to transmit various animal and human pathogens, suggesting the existence of evolutionally acquired proteolytic mechanisms. We report here the molecular and reverse genetic characterization of a multifunctional cysteine protease, longipain, from the babesial parasite vector tick Haemaphysalis longicornis. Longipain shares structural similarity with papain-family cysteine proteases obtained from invertebrates and vertebrates. Endogenous longipain was mainly expressed in the midgut epithelium and was specifically localized at lysosomal vacuoles and possibly released into the lumen. Its expression was up-regulated by host blood feeding. Enzymatic functional assays using in vitro and in vivo substrates revealed that longipain hydrolysis occurs over a broad range of pH and temperature. Haemoparasiticidal assays showed that longipain dose-dependently killed tick-borne Babesia parasites, and its babesiacidal effect occurred via specific adherence to the parasite membranes. Disruption of endogenous longipain by RNA interference revealed that longipain is involved in the digestion of the host blood meal. In addition, the knockdown ticks contained an increased number of parasites, suggesting that longipain exerts a killing effect against the midgut-stage Babesia parasites in ticks. Our results suggest that longipain is essential for tick survival, and may have a role in controlling the transmission of tick-transmittable Babesia parasites.     

Aplasia of the thumbs and great toes as the outstanding feature of Yunis and Varon syndrome. A new entity. A new observation

Aplasia of the thumbs and great toes, and aplasia of terminal and dysplasia of middle phalanges with absence of nails were noted in the child of related parents, who died at the age of 3 months from cardiorespiratory insufficiency. This is the 7th case of an (AR) genetic syndrome called after Yunis and Varon.     

Studies on ticks of veterinary importance in Nigeria XII. Oviposition and eclosion in five species of IXODID ticks in contrasting habitats

The preoviposition and oviposition periods, the eclosion periods and numbers of eggs laid by adult ticks of five species, namelyAmblyomma variegatum, Boophilus decoloratus, B. geigyi, Hyalomma rufipes andH. truncatum, maintained in a natural habitat were compared with those maintained in semi-natural and artificial habitats. Within the natural habitats, open and shady sites were distinguished.Maximum oviposition occurred during the peak of the rains in engorgedA. variegatum andB. decoloratus, and the numbers of eggs laid by those kept in the natural and semi-natural habitats were significantly lower in the dry season than in the rainy season. Maximum oviposition in engorgedH. rufipes kept in the natural habitat occurred during the early rains while minimum oviposition took place during the peak of the rains.Oviposition in engorgedH. truncatum was poor among those kept in the natural habitat during the peak and end of the rains. EngorgedA. variegatum andB. decoloratus kept in shady sites of the natural habitat laid significantly more eggs than in all other habitats at all seasons, while forH. truncatum andH. rufipes, numbers of eggs laid in the open site were significantly higher than those laid in other habitats at all seasons.In all species investigated, success in oviposition was aided by moisture provided by light to moderate rainfall, while excessive moisture in terms of heavy rainfall adversely affected oviposition.     

A non-specific aggregation pheromone in two Australian reptile ticks

Larvae, nymphs, adult males and adult females of each of the Australian reptile tick species Aponomma hydrosauri and Amblyomma limbatum took up significantly aggregated distributions when left for 12 h in the dark in petri dishes. Nymphs of the two species placed together formed co-aggregations. Pheromonal communication was implicated by the attraction of nymphs to filter paper squares which had been in contact with other nymphs. Each species was attracted to pheromone from the other species and no conspecific preference was detected. A common ancestral pheromone is suggested, which may have been retained after speciation by stabilizing selection for a behaviour of major importance to tick survival.     

Hemolymph proteins in ticks

In comparison to insects and Crustacea, our knowledge of the predominant hemolymph proteins in ticks is minimal. The hemolymph protein most studied in ticks has been vitellogenin (Vg). Vg is synthesized by the tick fat body after female adults obtain a blood meal, is released into the hemolymph and is absorbed by developing oocytes as vitellin (Vn). Much of what we know about Vg is from studies of Vn. In general, the carbohydrate, lipid and amino acid composition is similar to insects except that in the tick, Vg contains heme, most likely from the digestion of host hemoglobin. In the American dog tick, Dermacentor variabilis, Vg is comprised of two native proteins and seven subunits on SDS-PAGE. Vg has been characterized in five tick species but the amino acid sequence is not yet available. Another predominant hemolymph protein, apparently a carrier protein (CP), has recently been studied in two tick species. This protein is found in the hemolymph of both male and females adults, in adult tissues outside of the hemolymph in some tick species, in coxal fluid of soft ticks and in whole body homogenates from eggs, larvae and nymphs. CP from the hard tick, D. variabilis, contains cholesterol, phospholipids, monoacylglycerides, triacylglycerides, free fatty acids, carbohydrate and heme. Under identical assay conditions, the analogous protein in the soft tick, Ornithodoros parkeri, did not contain heme. CP in the American dog tick consists of two subunits, one of which has 61% identity to the biliprotein, artemocyanin, from the fairy shrimp. CP is identical to a heme-lipoprotein (HeLp) from Boophilus microplus. The exact roles of CP and HeLp have not yet been fully determined, but they apparently are important in heme sequestration and as a storage depot for protein and lipid. Macroglobulin, lectin, antimicrobial, JH binding, JH esterase, and other tick hemolymph proteins are also discussed.     

Borrelia sp. in ticks recovered from white-tailed deer in Alabama.

Six hundred sixty-five hunter-killed white-tailed deer (Odocoileus virginianus) from 18 counties in Alabama (USA) were examined for ticks. Most of the collections were made at state-operated wildlife management areas. Four species of ticks (n = 4,527) were recovered: the lone star tick Amblyomma americanum (n = 482); the Gulf Coast tick A. maculatum (n = 11); the winter tick Dermacentor albipictus (n = 1,242); and the black-legged tick Ixodes scapularis (n = 2,792). Fifty-six percent of the ticks (n = 2,555) were examined for Borrelia sp. spirochetes using an immunofluorescent, polyclonal antibody assay. Spirochetes were detected in I. scapularis (five females, seven males) from Barbour, Butler, Coosa, and Lee counties and A. americanum (four males, four nymphs) from Hale, Lee, and Wilcox counties. Area-specific prevalences in ticks were as high as 3.3% for I. scapularis and 3.8% for A. americanum.     

Pericentric inversions of the X chromosome. A new observation and review of the published cases

A pericentric inversion of the X chromosome-inv(X) (p11.3q22) is transmitted in 3 generations. Male and female carriers are normal. The proposita is tetraplegic, severely retarded and suffers from general seizures. Grand mal seizures are known in the mother and grandmother. Different proportions of inactive X chromosomes in the proposita and the normal sister are discussed. The published cases of inv(X) are reviewed.