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The deep fovea, sideways vision and spiral flight paths in raptors.

Raptors - falcons, hawks and eagles in this study - have two regions of the retina in each eye that are specialized for acute vision: the deep fovea and the shallow fovea. The line of sight of the deep fovea points forwards and approximately 45 degrees to the right or left of the head axis, while that of the shallow fovea also points forwards but approximately 15 degrees to the right or left of the head axis. The anatomy of the foveae suggests that the deep fovea has the higher acuity. Several species of raptors in this study repeatedly moved their heads among three positions while looking at an object: straight, with the head axis pointing towards the object; or sideways to the right or left, with the head axis pointing approximately 40 degrees to the side of the object. Since raptors do not rotate their eyes noticeably in the sockets, these movements presumably cause the image of the object to fall on the shallow and deep foveae. The movements occurred approximately every 2 s on average in hawks and falcons, and approximately every 5 s in bald eagles. The proportion of time that the raptors spent looking straight or sideways at an object depended on how far away the object was. At a distances closer than 8 m, they spent more time looking at the object straight, but as the distance increased to 21 m, they spent more time looking at it sideways. At distances of 40 m or more, raptors looked sideways at the object 80 % or more of the time. This dependence of head position on distance suggests that raptors use their more acute sideways vision to look at distant objects and sacrifice acuity for stereoscopic binocular vision to look at close objects. Having their most acute vision towards the side causes a conflict in raptors such as falcons, which dive at prey from great distances at high speeds: at a speed of 70 m s(-)(1), turning their head sideways to view the prey straight ahead with high visual acuity may increase aerodynamic drag by a factor of 2 or more and slow the raptor down. Raptors could resolve this conflict by diving along a logarithmic spiral path with their head straight and one eye looking sideways at the prey, rather than following the straight path to the prey with their head turned sideways. Although the spiral path is longer than the straight path, a mathematical model for an 'ideal falcon' shows that the falcon could reach the prey more quickly along the spiral path because the speed advantage of a straight head more than compensates for the longer path.

Air Movements↗

A survey of the aerobic bacteria in the feces of captive raptors.

Feces of 47 captive raptors belonging to the order Falconiformes or Strigiformes were cultured for bacteria. Gram-negative bacteria, which were cultured from the feces of 45 of the 47 raptors, were the most common isolates. A wide variety of species were identified, including a newly described genus (Moellerella wisconsensis), two newly described species (Escherichia fergusonii and Proteus penneri), and a member of a newly described enteric group (CDC Enteric group 41). Additional organisms identified that have not been reported in previous bacteriological surveys of raptors were Salmonella heidelberg, Salmonella braenderup, Morganella morganii, Yersinia ruckeri, Serratia spp., and Kluyvera sp. Escherichia coli, isolated from the feces of 42 of the 47 raptors, was the most frequently recovered. Streptococcus faecalis, the second most common isolate, was cultured from 30 birds. Several differences were observed between fecal bacteria isolated from raptors fed commercially prepared chicken and those isolated from raptors not fed chicken. The most obvious difference was that birds fed chicken had more varied gram-negative bacterial species and in greater numbers per fecal sample. The potential for the isolated bacteria from raptors as pathogens in humans and avian species is discussed.

Animals↗

Raptor, a binding partner of target of rapamycin (TOR), mediates TOR action.

mTOR controls cell growth, in part by regulating p70 S6 kinase alpha (p70alpha) and eukaryotic initiation factor 4E binding protein 1 (4EBP1). Raptor is a 150 kDa mTOR binding protein that also binds 4EBP1 and p70alpha. The binding of raptor to mTOR is necessary for the mTOR-catalyzed phosphorylation of 4EBP1 in vitro, and it strongly enhances the mTOR kinase activity toward p70alpha. Rapamycin or amino acid withdrawal increases, whereas insulin strongly inhibits, the recovery of 4EBP1 and raptor on 7-methyl-GTP Sepharose. Partial inhibition of raptor expression by RNA interference (RNAi) reduces mTOR-catalyzed 4EBP1 phosphorylation in vitro. RNAi of C. elegans raptor yields an array of phenotypes that closely resemble those produced by inactivation of Ce-TOR. Thus, raptor is an essential scaffold for the mTOR-catalyzed phosphorylation of 4EBP1 and mediates TOR action in vivo.

Adaptor Proteins, Signal Transducing↗

GbetaL, a positive regulator of the rapamycin-sensitive pathway required for the nutrient-sensitive interaction between raptor and mTOR.

mTOR and raptor are components of a signaling pathway that regulates mammalian cell growth in response to nutrients and growth factors. Here, we identify a member of this pathway, a protein named GbetaL that binds to the kinase domain of mTOR and stabilizes the interaction of raptor with mTOR. Like mTOR and raptor, GbetaL participates in nutrient- and growth factor-mediated signaling to S6K1, a downstream effector of mTOR, and in the control of cell size. The binding of GbetaL to mTOR strongly stimulates the kinase activity of mTOR toward S6K1 and 4E-BP1, an effect reversed by the stable interaction of raptor with mTOR. Interestingly, nutrients and rapamycin regulate the association between mTOR and raptor only in complexes that also contain GbetaL. Thus, we propose that the opposing effects on mTOR activity of the GbetaL- and raptor-mediated interactions regulate the mTOR pathway.

Adaptor Proteins, Signal Transducing↗

Pasteurella multocida in raptors: prevalence and characterization.

Several cases dealing with Pasteurella multocida infection have been documented in raptors. However, the isolates have not been fully characterized nor has the prevalence of P. multocida in raptors been determined. Three hundred ninety-eight raptors were cultured for P. multocida. Results indicated that P. multocida was not normally carried in the pharyngeal, choanal, or cloacal regions. However, P. multocida was isolated from raptors with avian cholera. Isolates from eight cases were characterized by biotype, somatic serotype, and antibiogram. Most (six of eight) of the P. multocida isolates belonged to somatic serotype 1. The remaining two P. multocida isolates belonged to somatic serotypes 3 and 3,4. The majority of the isolates belonged to the subspecies multocida. All isolates were susceptible to penicillin G, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. Various restriction site heterogeneities of P. multocida chromosomal DNA were found among the raptor isolates. Results indicated that isolates of P. multocida somatic serotype 1 from diurnal raptors were genetically related.

Animals↗

Lead poisoning of raptors in France and elsewhere.

Although lead poisoning, through the ingestion of gunshot embedded in prey, is known to have been a significant mortality factor for several raptor species in the United States (Haliaeetus leucocephalus and Gymnogyps Californianus), very little published information is available concerning raptors in Europe. This paper presents the results of liver lead analysis from 222 raptors collected throughout France and reviews other published and unpublished European information. Of the 11 diurnal and 6 nocturnal raptor species investigated in this study, elevated liver lead concentrations, suggestive of shot ingestion, were found in 3 (Accipiter nisus, A. gentilis, Buteo buteo). The likelihood of a species to ingest shot appears related to feeding habits, with scavengers and predators that take game species the most susceptible. Raptor species at risk from lead poisoning, including some of high conservation value, are described, and future priorities for lead poisoning research and policy are suggested.

Animals↗

mTOR interacts with raptor to form a nutrient-sensitive complex that signals to the cell growth machinery.

mTOR/RAFT1/FRAP is the target of the immunosuppressive drug rapamycin and the central component of a nutrient- and hormone-sensitive signaling pathway that regulates cell growth. We report that mTOR forms a stoichiometric complex with raptor, an evolutionarily conserved protein with at least two roles in the mTOR pathway. Raptor has a positive role in nutrient-stimulated signaling to the downstream effector S6K1, maintenance of cell size, and mTOR protein expression. The association of raptor with mTOR also negatively regulates the mTOR kinase activity. Conditions that repress the pathway, such as nutrient deprivation and mitochondrial uncoupling, stabilize the mTOR-raptor association and inhibit mTOR kinase activity. We propose that raptor is a missing component of the mTOR pathway that through its association with mTOR regulates cell size in response to nutrient levels.

Adaptor Proteins, Signal Transducing↗

Prevalence of encysted Toxoplasma gondii in raptors from Alabama.

Little is known about the prevalence of encysted Toxoplasma gondii in wild birds. We examined the hearts and breast muscles from 101 raptors for encysted T. gondii. All of the raptors had been submitted for necropsy to the State Veterinary Diagnostic Laboratory, Auburn, Alabama. Tissues were digested in acid-pepsin solution and inoculated into groups of 3-5 laboratory mice. Toxoplasma gondii was isolated from 27 of 101 (26.7%) raptors: 8 of 12 (66.7%) red-shouldered hawks (Buteo lineatus), 13 of 27 (41.1%) red-tailed hawks (Buteo jamaicensis), 1 of 4 (25%) Cooper's hawks (Accipiter cooperi), 1 of 5 (20%) great horned owls (Bubo virginianus), 4 of 15 (26.7%) barred owls (Strix varia), and 1 of 3 (33.3%) kestrels (Falco sparverius). Toxoplasma gondii was not isolated from 3 broad-winged hawks (Buteo platypterus), 3 sharp-shinned hawks (Accipiter striatus), 6 barn owls (Tyto alba), 9 screech owls (Asio otus), a Mississippi kite (Ictinia misisippiensis), 2 golden eagles (Aquila chrysaetos), a bald eagle (Haliaeetus leucocephalus), 4 ospreys (Pandion haliaetus), 4 turkey vultures (Cathartes aura), or 2 black vultures (Coragyps atratus). No significant difference (P > 0.05) in prevalence was detected based on sex using chi-square analysis. Chi-square analysis of the data demonstrated that adult raptors had encysted stages of T. gondii significantly (P < 0.05) more often than did immature raptors.

Age Factors↗

A retrospective study of morbidity and mortality of raptors in Florida: 1988-1994.

A retrospective study was conducted on 390 raptors admitted to the University of Florida Veterinary Medical Teaching Hospital (VMTH) during 1988-1994. Representatives of 20 species were admitted; the five most common species were the barred owl (Strix varia, 72), eastern sreech owl (Otus asio, 63), red-shouldered hawk (Buteo lineatus, 49), bald eagle (Haleaeetus leucocephalus, 43), and red-tailed hawk (Buteo jamaicensis, 38). A primary clinical diagnosis was determined in 340 (87%) of the 390 raptors admitted to the VMTH; a diagnosis was not made for the remaining 50 birds. Eighty-two percent (279) had traumatic injuries, and 87% (243) of those were directly related to human activity. The primary clinical diagnoses in the remaining 61 raptors included toxicosis (21), poor nutrition (15), infectious disease (11), orphaned young (11), and electrocution (3). The disposition of the 390 raptors was as follows: 61% (237) died or euthanized, 21% (80) released to the wild, 15% (57) outcome unknown, and 4% (16) permanent captives. Necropsies were performed on 32 of the 237 raptors that died.

Animals↗

Raptor therapeutics.

Developing a therapeutic plan for raptors can be challenging because the veterinarian must take numerous and sometimes conflicting factors into consideration. Successful therapy depends on proper management of the raptor patient, beginning with its initial presentation and continuing throughout its time in captivity. Important considerations concerning medicine and natural history peculiar to raptors are addressed. Guidelines for constructing an effective therapeutic plan for the treatment of common diseases and conditions seen in wild raptors are presented.

Animals↗

Emergency care of raptors.

Emergency care of raptors often requires extensive diagnostics and therapeutic regimens to stabilize and support the ill or injured raptor. Whether falconry birds, educational birds, or raptors from the wild are presented, various medical conditions must be addressed to help guide the practitioner toward a complete recovery for the raptor.

Animal Husbandry↗

Trypanosoma avium of raptors (Falconiformes): phylogeny and identification of vectors.

Avian trypanosomes are widespread parasites of birds, the transmission of which remains mostly unclear, with various blood-sucking insects mentioned as possible vectors. A search for vectors of trypanosomes of sparrowhawk (Accipiter nisus), buzzard (Buteo buteo), lesser-spotted eagle (Aquila pomarina) and kestrel (Falco tinnunculus) was performed in Czech and Slovak Republics. Black flies (Eusimulium spp.), hippoboscid flies (Ornithomyia avicularia), mosquitoes (Culex pipiens pipiens) and biting midges (Culicoides spp.), trapped while attempting to feed on raptor nestlings, were found to contain trypanosomatids in their intestine. Trypanosomes from the raptors and blood-sucking insects were isolated, and their 18S rRNA sequences were used for species identification and for the inference of intra- and interspecific relationships. Together with the trypanosome isolated from a black fly, the bird trypanosomes formed a well-supported Trypanosoma avium clade. The isolates derived from hippoboscid flies and mosquitoes are most likely also avian trypanosomes infecting birds other than the studied raptors. Analysis of the kinetoplast, that has features characteristic for the avian trypanosomes (minicircle size; dimensions of the kinetoplast disc), provided further evidence for the identification of vectors. It is suggested that all trypanosomes isolated from raptors included in this study belong to the T. avium complex and are transmitted by the ornithophilic simuliids such as Eusimulium securiforme.

Animals↗

Habitat loss and raptor predation: disentangling long- and short-term causes of red grouse declines.

The number of red grouse (Lagopus lagopus scoticus) shot in the UK has declined by 50% during the 20th century This decline has coincided with reductions in the area of suitable habitat and recoveries in the populations of some avian predators. Here we use long-term records of shooting bags and a large-scale manipulation of raptor density to disentangle the effects of habitat loss and raptor predation on grouse populations. The numbers of grouse harvested on the Eskdale half of Langholm Moor in southern Scotland declined significantly during 1913-1990 and grouse bags from the whole moor from 1950 to 1990 exhibited an almost identical but non-significant trend. Hen harriers (Circus cyaneus) and peregrine falcons (Falco peregrinus) were absent or bred at low densities on this moor throughout this period but heather-dominant vegetation declined by 48% between 1948 and 1988. Harrier and peregrine breeding numbers on Langholm Moor increased to high levels following protection in 1990 whilst grouse density and grouse bags declined year after year until shooting was abandoned in 1998. The prediction of a peak in grouse bags on Langholm Moor in 1996 based on the patterns of bags during 1950-1990 was supported by the observed peaks in 1997 on two nearby moors with few raptors which formerly cycled in synchrony with Langholm Moor. This study demonstrates that, whilst long-term declines in grouse bags were most probably due to habitat loss, high levels of raptor predation subsequently limited the grouse population and suppressed a cycle. This study thus offers support to theoretical models which predict that generalist predators may suppress cycles in prey populations.

Animals↗

A retrospective study of the success of medical and surgical treatment of wild Australian raptors.

OBJECTIVE: To evaluate the results of medical and surgical regimens utilised to treat injured and diseased wild Australian raptors presented at our practice, and to determine if the time, effort and cost of treating the birds was justified in terms of the outcomes achieved. PROCEDURE: All the practice's clinical records relating to the examination and treatment of wild raptors were reviewed for the period April 1994 to December 1998. The species of birds, the aetiology of their injuries or diseases, the treatment protocols and the outcomes of those treatments were correlated and tabulated for evaluation. RESULTS: Fifteen Australian species of raptor were examined and treated. Complete records were available for 104 birds of prey, 73 being Accipitriformes and 31 Strigiformes. The poorest prognosis was for birds involved in motor vehicle impacts, while birds suffering malnutrition or starvation had higher survival rates. The overall rate of survival was 50%. CONCLUSION: Based on the severity of diseases and injuries at the time of presentation, the survival rate was considered acceptable. Veterinary involvement in the treatment of the wild raptors was necessary for the maintenance of the birds' welfare, and to determine appropriate treatments. Intangible benefits included increased practice staff satisfaction, and improving the veterinary professions' public image by providing pro bono treatment for Australian wildlife.

Animals↗

Environmental exposure and distribution of lead in four species of raptors in Southeastern Spain.

The purpose of this study was to monitor exposure to lead in four species of raptors in Southeastern Spain (Murcia Region). Samples of liver, kidney, brain, blood, and bone from two species of diurnal raptors (European kestrel (Falco tinnunculus) and European buzzard (Buteo buteo)) and two species of nocturnal raptors (Eagle owl (Bubo bubo) and Little owl (Athene noctua)) were obtained during 1994. Relationships were found between size and age of the birds, the nearness to areas of human activity and lead concentrations in tissues. The lead distribution pattern reveals that the bone is the principle organ for accumulation (0.62-43 mg/Kg, dry weight), followed by the kidney (0.03-0.66 mg/Kg, wet weight), and liver (0. 017-0.05 mg/Kg, w.w.), and to lesser extent, the brain (0.013-0.223 mg/Kg, w.w.). This distribution pattern indicates that raptors in Southeastern Spain were exposed to environmental low lead levels continuously over an extended period of time. Correlations between lead in bone and lead in soft tissues were higher in European buzzards (r = 0.87-0.95) and Eagle owl (r = 0.71-0.86) than those found in European kestrels (r = 0.53-0.58) and Little owls (r << 0). However, correlations between lead concentrations in soft tissues and in blood were high (r = 0.85-0.99).

Animals↗

The mammalian target of rapamycin (mTOR) partner, raptor, binds the mTOR substrates p70 S6 kinase and 4E-BP1 through their TOR signaling (TOS) motif.

The mammalian target of rapamycin (mTOR) controls multiple cellular functions in response to amino acids and growth factors, in part by regulating the phosphorylation of p70 S6 kinase (p70S6k) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). Raptor (regulatory associated protein of mTOR) is a recently identified mTOR binding partner that also binds p70S6k and 4E-BP1 and is essential for TOR signaling in vivo. Herein we demonstrate that raptor binds to p70S6k and 4E-BP1 through their respective TOS (conserved TOR signaling) motifs to be required for amino acid- and mTOR-dependent regulation of these mTOR substrates in vivo. A point mutation of the TOS motif also eliminates all in vitro mTOR-catalyzed 4E-BP1 phosphorylation and abolishes the raptor-dependent component of mTOR-catalyzed p70S6k phosphorylation in vitro. Raptor appears to serve as an mTOR scaffold protein, the binding of which to the TOS motif of mTOR substrates is necessary for effective mTOR-catalyzed phosphorylation in vivo and perhaps for conferring their sensitivity to rapamycin and amino acid sufficiency.

Adaptor Proteins, Signal Transducing↗

Two motifs in the translational repressor PHAS-I required for efficient phosphorylation by mammalian target of rapamycin and for recognition by raptor.

Mammalian target of rapamycin (mTOR) is the central element of a signaling pathway involved in the control of mRNA translation and cell growth. The actions of mTOR are mediated in part through the phosphorylation of the eukaryotic initiation factor 4E-binding protein, PHAS-I. In vitro mTOR phosphorylates PHAS-I in sites that control PHAS-I binding to eukaryotic initiation factor 4E; however, whether mTOR directly phosphorylates PHAS-I in cells has been a point of debate. The Arg-Ala-Ile-Pro (RAIP motif) and Phe-Glu-Met-Asp-Ile (tor signaling motif) sequences found in the NH2- and COOH-terminal regions of PHAS-I, respectively, are required for the efficient phosphorylation of PHAS-I in cells. Here we show that mutations in either motif markedly decreased the phosphorylation of recombinant PHAS-I by mTOR in vitro. Wild-type PHAS-I, but none of the mutant proteins, was coimmunoprecipitated with hemagglutinin-tagged raptor, an mTOR-associated protein, after extracts of cells overexpressing raptor had been supplemented with recombinant PHAS-I proteins. Moreover, raptor overexpression enhanced the phosphorylation of wild-type PHAS-I by mTOR but not the phosphorylation of the mutant proteins. The results not only provide direct evidence that both the RAIP and tor signaling motifs are important for the phosphorylation by mTOR, possibly by allowing PHAS-I binding to raptor, but also support the view that mTOR phosphorylates PHAS-I in cells.

Adaptor Proteins, Signal Transducing↗

Chlamydiosis in captive raptors.

Chlamydia psittaci was isolated from four red-tailed hawks (Buteo jamaicensis) that died suddenly and from seven birds that survived at a raptor rehabilitation center in California in 1983. One hundred captive raptors representing 14 species in five families were subsequently tested serologically and by direct cloacal culture. C. psittaci was isolated from seven clinically normal birds. Forty-four percent of the raptors were considered positive using an enzyme-linked immunosorbent assay (ELISA), and 19% were suspects. The ELISA was repeated on 54 raptors in 1986. Forty-one percent of the birds were considered positive, and 35% were suspect, indicating that C. psittaci is endemic in the population.

Animals↗