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At least 109 records · Page 6Linked to original sources
PubMed1999

Identification of genes controlling malpighian tubule and other epithelial morphogenesis in Drosophila melanogaster.

The Drosophila Malpighian tubule is a model system for studying genetic mechanisms that control epithelial morphogenesis. From a screen of 1800 second chromosome lethal lines, by observing uric acid deposits in unfixed inviable embryos, we identified five previously described genes (barr, fas, flb, raw, and thr) and one novel gene, walrus (wal), that affect Malpighian tubule morphogenesis. Phenotypic analysis of these mutant embryos allows us to place these genes, along with other previously described genes, into a genetic pathway that controls Malpighian tubule development. Specifically, wal affects evagination of the Malpighian tubule buds, fas and thr affect bud extension, and barr, flb, raw, and thr affect tubule elongation. In addition, these genes were found to have different effects on development of other epithelial structures, such as foregut and hindgut morphogenesis. Finally, from the same screen, we identified a second novel gene, drumstick, that affects only foregut and hindgut morphogenesis.

Animals↗
PubMed1989

Trichinosis in the Canadian Arctic: report of five outbreaks and a new clinical syndrome.

Trichinosis is a serious but understudied medical problem in the Arctic. Forty-nine consecutive cases in the Inuit population of northeastern Canada are described. Most developed the disease after eating raw walrus, and the clinical presentation of most of these cases differed from previously reported descriptions of classic trichinosis due to Trichinella spiralis. Unlike the classic syndrome of a brief period of diarrhea followed by fever, myalgia, muscle weakness, and edema, the most common presentation in these cases was a prolonged diarrhea without fever and with brief muscle symptoms. High peripheral eosinophilia, high Trichinella antibody serotiters, and little direct or indirect evidence of muscle invasion in many of those with the chronic diarrheal presentation suggest a new clinical syndrome due to a different species of Trichinella seen in the Arctic or to reinfection with Trichinella.

Animals↗
PubMed1995

Arctic indigenous women consume greater than acceptable levels of organochlorines.

Exposure to polychlorinated biphenyls and organochlorine pesticides through traditional food resources was examined for Arctic Indigenous women living in two cultural and environmental areas of the Canadian Arctic--one community representing Baffin Island Inuit in eastern Arctic and two communities representing Sahtú Dene/Métis in western Arctic. Polychlorinated biphenyls, toxaphene, chlorobenzenes, hexachlorocyclohexanes, dichlorodiphenyltrichloroethane, chlordane-related compounds and dieldrin were determined in local food resources as normally prepared and eaten. Quantified dietary recalls taken seasonally reflected normal consumption patterns of these food resources by women in three age groups: 20-40 y, 41-60 y and > or = 61 y. There was wide variation of intake of all organochlorine contaminants in both areas and among age groups for the Sahtú. Fifty percent of the intake recalls collected from the Baffin Inuit exceeded the acceptable daily intake for chlordane-related compounds and toxaphene, and a substantial percentage of the intake records for dieldrin and polychlorinated biphenyls exceeded the acceptable or tolerable daily intake levels. Primary contributing foods to organochlorine contaminants intake for the Baffin Inuit were meat and blubber of ringed seal, blubber of walrus and mattak and blubber of narwal. Important foods contributing organochlorine contaminant to the Sahtú Dene/Métis were caribou, whitefish, inconnu, trout and duck. The superior nutritional benefits and potential health risks of traditional food items are reviewed, as are implications for monitoring organochlorine contaminant contents of food, clinical symptoms and food use.

Adult↗
PubMed2006

Primer Extension Enrichment Reaction (PEER): a new subtraction method for identification of genetic differences between biological specimens.

We developed a conceptually new subtraction strategy for the detection and isolation of target DNA and/or RNA from complex nucleic acid mixtures, called Primer Extension Enrichment Reaction (PEER). PEER uses adapters and class IIS restriction enzymes to generate tagged oligonucleotides from dsDNA fragments derived from specimens containing an unknown target ('tester'). Subtraction is achieved by selectively disabling these oligonucleotides by extension reaction using ddNTPs and a double stranded DNA template generated from a pool of normal specimens ('driver'). Primers that do not acquire ddNTP are used to capture and amplify the unique target DNA from the original tester dsDNA. We successfully applied PEER to specimens containing known infectious agents (Hepatitis B Virus and Walrus Calicivirus) and demonstrated that it has higher efficiency than the best comparable technique. The strategy used for PEER is versatile and can be adapted for the identification of known and unknown pathogens and mutations, differential expression studies and other applications that allow the use of subtractive strategies.

Caliciviridae↗
PubMed2001

Ecological risk assessment framework for low-altitude aircraft overflights: II. Estimating effects on wildlife.

An ecological risk assessment framework for aircraft overflights has been developed, with special emphasis on military applications. This article presents the analysis of effects and risk characterization phases; the problem formulation and exposure analysis phases are presented in a companion article. The framework addresses the effects of sound, visual stressors, and collision on the abundance and production of wildlife populations. Profiles of effects, including thresholds, are highlighted for two groups of endpoint species: ungulates (hoofed mammals) and pinnipeds (seals, sea lions, walruses). Several factors complicate the analysis of effects for aircraft overflights. Studies of the effects of aircraft overflights previously have not been associated with a quantitative assessment framework; therefore no consistent relations between exposure and population-level response have been developed. Information on behavioral effects of overflights by military aircraft (or component stressors) on most wildlife species is sparse. Moreover, models that relate behavioral changes to abundance or reproduction, and those that relate behavioral or hearing effects thresholds from one population to another are generally not available. The aggregation of sound frequencies, durations, and the view of the aircraft into the single exposure metric of slant distance is not always the best predictor of effects, but effects associated with more specific exposure metrics (e.g., narrow sound spectra) may not be easily determined or added. The weight of evidence and uncertainty analyses of the risk characterization for overflights are also discussed in this article.

Aircraft↗
PubMed2002

The squatters and the blowflies.

Cutaneous myiasis in Australian sheep became an increasing problem in the early years of the 20th century after the import of the wrinkly Vermont Merinos and the introduction of Lucillia cuprina. WE Abbott, a successful pastoralist in New South Wales at that time, wrote a little-known and unusual description of early methods of control: a parody based on an episode in Through the Looking Glass by Lewis Carroll. The plight of struck sheep and the lives and times of Abbott, several other pastoralists and the entomologists of the New South Wales Department of Agriculture are illuminated as the Walrus and the Carpenter walk again across the hills and pastures of New South Wales.

Animals↗
PubMed2004

Localization of aerial broadband noise by pinnipeds.

Although many pinnipeds (seals, sea lions, and walruses) emit broadband calls on land as part of their communication system, few studies have addressed these animals' ability to localize aerial broadband sounds. In this study, the aerial sound localization acuities of a female northern elephant seal (Mirounga angustirostris), a male harbor seal (Phoca vitulina), and a female California sea lion (Zalophus californianus) were measured in the horizontal plane. The stimulus was broadband white noise that was band pass filtered between 1.2 and 15 kHz. Testing was conducted in a hemi-anechoic chamber using a left/right forced choice procedure to measure the minimum audible angle (MAA) for each subject. MAAs were defined as half the angular separation of two sound sources bisected by a subject's midline that corresponded to 75% correct discrimination. MAAs were 4.7 degrees, 3.6 degrees, and 4.2 degrees for the northern elephant seal, harbor seal, and California sea lion, respectively. These results demonstrate that individuals of these pinniped species have sound localization abilities comparable to the domestic cat and rhesus macaque. The acuity differences between our subjects were small and not predicted by head size. These results likely reflect the relatively acute general abilities of pinnipeds to localize aerial broadband signals.

Animals↗
PubMed2004

Impact of economic changes on the diet of Chukotka Natives.

This paper describes and analyses changes in food composition and nutritional preferences among the Chukchi and Yupik of coastal Chukotka in the last 15 years. The economic collapse of the infrastructure of Chukotka region has resulted in many indigenous northerners reverting to the traditional subsistence economy. Relatively expensive market foods are being replaced by cheaper ones, and by more readily available local foods. Percent contribution of proteins, lipids and carbohydrates to total caloric intake has not changed substantially, but sources of the major nutrients have become different. In 1985, local marine mammals accounted for about half of the consumed meat (55%), while in 2000 the share of it increased to 89 %. Market fats and oils are also being substituted by the fat of marine mammals. However, the contemporary diet of the natives of coastal Chukotka differs significantly from the traditional one. The meat of seals and gray whales (small sized and less dangerous to harvest) remains seasonally accessible, but can not be stored for long times. There is an insufficient amount of walrus and bowhead whale meat, which can be prepared in traditional style by fermentation, and stored for a long time. This probably also provides a specific protection against Helicobacter pylori. The young people today are more oriented towards local food-stuff: 76 % Coastal Chukchee and Yupik under the age of 30 indicated a preference for native foods over European ("Russian") ones, while this share is lower (66 %) among people older than 30 years. Overall, 86 % of natives consider that whale hunting, as the main source of food, should be increased (in 1985, only 45% suggested so).

Arctic Regions↗
PubMed1982

Nasal mites (Acari:Halarachnidae) in the spotted seal, Phoca largha Pallas, and other pinnipeds of Alaskan waters.

The nasal passages of 349 pinnipeds of seven species were examined for halarachnid mites. Each of seven Steller sea lions (Eumetopias jubatus), 75 of 99 harbor seals (Phoca vitulina), and four of 71 spotted seals (P. largha) were infected, but none of 28 walruses (Odobenus rosmarus), 43 ringed seals (Phoca hispida), 58 ribbon seals (P. fasciata), and 43 bearded seals (Erignathus barbatus) was infected. The sea lions harbored Orthohalarachne attenuata (Banks, 1910) and O. diminuata (Doetschman, 1944), and the harbor and spotted seals harbored Halarachne halichoeri Allman, 1847. The finding of H. halichoeri in the spotted seals is a new host record.

Alaska↗
PubMed1987

Antibodies to marine caliciviruses in the Steller sea lion (Eumetopias jubatus Schreber).

Sera from 145 Steller sea lions (76 adults, three subadults, 37 pups, and 29 fetuses) were tested for neutralizing antibodies to nine marine calicivirus serotypes. Antibodies were found to San Miguel sea lion virus (SMSV) types 1, 5, 6, 7, 8, 10 and 13, and to Tillamook (bovine) calicivirus, but no antibodies were found to the walrus calicivirus. Titers (microtiter neutralization assay) ranged from 1:20 to 1:320, with many positive reactions at the higher dilutions (greater than or equal to 1:80). Antibodies to SMSV's 5 and 10 were most common among animals sampled in Alaskan waters, while antibodies to SMSV-6 were most common among pups from the southern Oregon coast. These data provide evidence that Steller sea lions, like their California sea lion (Zalophus c. californianus Lesson) counterparts, have experienced widespread exposure to multiple serotypes of marine caliciviruses.

Animals↗
PubMed1988

The use of meperidine hydrochloride for chemical restraint in certain cetaceans and pinnipeds.

Meperidine HCl was administered intramuscularly by hand-syringe to a number of individuals representing several species of cetaceans (n = 95) and pinnipeds (n = 36). Dosage administered was 0.11 mg/kg, 0.23 mg/kg or 0.45 mg/kg, with the majority of animals receiving the middle dosage. Meperidine HCl provided moderate restraint in cetaceans without obvious deleterious effects. Restraint was achieved rapidly, with maximum effect occurring 20 min after intramuscular injection and lasting for 2 to 3 hr. Analgesia appeared to last as long as 4 hr and was sometimes accompanied by a restoration of appetite in animals suffering from physical discomfort. Higher doses produced increased sedation and analgesia without noticeably depressing respiration. Meperidine HCl provided moderate restraint for phocids and walrus (Odobenus rosmarus) without apparent detriment. California sea lions (Zalophus californianus) showed little restraint, but demonstrated profound respiratory depression.

Animals↗
PubMed1998

Twenty years of trace metal analyses of marine mammals in Alaska: evaluation and summation.

The compilation of existing data on contaminants in the marine food chain is essential in addressing concerns regarding the magnitude of potential human exposures and in the evaluation of subsistence food safety. This paper presents a summary of studies on trace metals in tissues of Alaska marine mammals from the 1970s to the present, along with derived mean tissue trace metal concentrations. The derived mean can serve as a norm against which future monitoring results may be compared, and may be used to estimate human exposure to trace metals through the consumption of marine mammals. Additionally, the variation among studies in the reported mean tissue concentrations has been described through a derived standard deviation. Sufficient analytical and methodological details were available to derive means and standard deviations for tissues in bearded seal, bowhead whale, beluga whale, fur seal, harbor seal, Pacific walrus, and ringed seal. A high concordance between trace metal values reported in tissues (i.e., liver, kidney, muscle) was observed despite significant differences in reported sampling and analytical methodologies. Consistent with other reviews of trace metal concentrations in marine species, the standard deviation of tissue metal concentrations was generally < or = 100% of the reported mean. Significant gaps in available information remain, particularly for muscle tissues and for methylmercury, despite the considerable efforts to monitor marine mammal species in Alaska.

Alaska↗
PubMed1991

Trichinosis surveillance, United States, 1987-1990.

Since the Public Health Service began recording statistics on trichinosis in 1947, the number of cases reported by state health departments each year has declined. In the late 1940s, health departments reported an average of 400 cases and 10-15 deaths each year; from 1982 through 1986, the number declined to an average of 57 cases per year and a total of three deaths for the period. From 1987 through 1990, 206 cases of trichinosis from 22 states, including 14 multiple-case outbreaks, were reported to CDC. In 1990, two large outbreaks associated with commercial pork accounted for 106 cases. In the 192 instances in which a suspect food item was identified, pork was implicated in 144 (75%) cases, walrus meat in 34 (18%), and bear meat in 14 (7%). Sausage, the most frequently implicated pork product, was associated with 128 of the 139 cases for which a form of ingested pork was specified. Before 1990, the proportion of cases of trichinosis attributable to consumption of commercial pork had declined steadily. This decline was probably due to a combination of factors, including laws prohibiting the feeding of garbage to hogs, the increased use of home freezers, and the practice of thoroughly cooking pork. Although the incidence of trichinosis has decreased substantially since national reporting was initiated in 1947, a dramatic increase in 1990, resulting from two large outbreaks, emphasizes the need for further education and control measures.

Adolescent↗
PubMed1990

The megachiropteran pineal organ: a comparative morphological and volumetric investigation with special emphasis on the remarkably large pineal of Dobsonia praedatrix.

This investigation is based upon the pineal organs of 92 specimens of 36 species of the family Pteropodidae (Mammalia, Chiroptera). The size of the megachiropteran pineal correlates well with body size (r = 0.864), confirming the former conclusions that generally larger bodied bats have larger pineals. The range of the pineal size index in 36 megachiropteran species is from 33 to 4393. In most species the pineal organs are small, deeply recessed under the cerebral hemispheres and of Type A (except in Dobsonia and Pteropus, where they are of Type alpha beta C and AB, respectively). Morphological and volumetric data gathered from serially sectioned brains include body and brain weights, pineal type, dimensions, volume and size index for each species. There are distinct dorsal and ventral subdivisions of the pineal in some species and a clear separation of pineal parenchyma into cortical and medullary regions in others. In several species where overlying ependyma is lacking pinealocyte clusters communicate freely with the CSF. Groups of intrapineal neurons are noted in the connective tissue beside blood vessels. The habenular commissure shows much interspecific variation in its course through the pineal. Detailed examination of pineal-brain relationships clearly suggests that, due to the generally deep location of the pineal in relation to cerebral hemispheres, pinealectomies in the species studied may be extremely difficult, it not entirely impossible. The absolutely and relatively largest pineal organ among bats, and relatively perhaps among all vertebrates, has been discovered in the New Guinean naked-backed bat, Dobsonia praedatrix, with pineal size index of 4393, and a volume of 16.3447 mm3, which is 0.56% of the brain. This alpha beta C-type, mushroom-shaped, solid and compact pineal organ measures 5.33 x 4.51 mm. The cortical and medullary parenchyma are divided into lobes by large calibre blood vessels along which numerous intrapineal neurons are observed. A smaller but similarly shaped pineal is noted in the other three Dobsonia. Data on the largest known pineals in ratitae birds, seals and walruses have been compared with that of D. praedatrix and the human pineal. This study supports the hypothesis that pineal development may reflect dependence on habitat and possibly other related factors.

Animals↗
PubMed1988

[Macromutation and evolution: the fixation of Goldschmidt's macromutations as species and genus traits. Hairlessness mutations in mammals].

A brief survey of the development of concepts on the role of macromutations in evolution is given. Contrary to Iu. A. Filipchenko (1926, 1927), who introduced the "micro- and macromutation" terms and believed that regularities of macroevolution could not be reduced to microevolutionary processes, the majority of "synthetists" explained any form of evolution by changes in allele frequencies. From the studies of Drosophila homoeotic mutants R. Goldschmidt (1940) developed the concept of "hopeful monsters" and their role in macroevolution. However, the homoeotic mutants are of drastically reduced viability, which allows the gradualists to reject Goldschmidt's ideas. The distribution of hairlessness mutations (hairless, nude etc.) with the monogenic pattern of inheritance in mammals was studied. Hairless mutants are known in Peromyscus, Mus musculus, Rattus rattus, R. norvegicus, Canis familiaris, Ovis aries. Hairlessness as norm is found in 53 among contemporaneous 1037 mammalian genera. Part of these cases (hairlessness in all Cetacea and Sirenia) may be explained in terms of both macromutations and obligatory gradualism. There is no doubt as to the macromutational origin of hairlessness in the bat Cheiromeles and the rodent Heterocephalus (Bathyergidae); the genera systematically and ecologically close to these have normal pelage. It is quite possible that hairlessness of walrus (Odobenus) has the same origin. The appearance and fixation of single Goldschmidt's macromutation cannot yet be considered as a macroevolutionary process, though the possibility of fixation of a macromutation in nature as a species and genus character contradicts strongly the concept of obligatory gradualism of evolution.

Animals↗
PubMed1982

[The position of seals in the system of mammals (author's transl)].

The common seal Phoca vitulina belongs to the order Pinnipedia, a group of marine mammals, the majority of which live in the colder seas. Two main groups are differentiated within this order: Otarioidea and Phocoidea. The Otarioidea are divided into two families: Otariidae (sea lions and fur seals) and Odobenidae (walruses): the Phocoidea consist of the family Phocidae (seals) only. The Pinnipedia are closely related to the order Carnivora: they probably originated about 50 million years ago from a group of mammals related to bears. Otarioidea and Phocoidea are now usually regarded as close relatives, n view of among others, biochemical and parasitological characters.

Animals↗
PubMedDate not supplied

Hunting poisons of the North Pacific Region.

The hunting poisons of the North Pacific region are discussed. The most important one used by the Ainu was based on Aconitum species (surku or suruku): on Hokkaido, to some extent A. japonicum Thumb. but probably mainly A. yezoense Nakai and A. sachalinense Fr. Schm.; on southern Sakhalin, perhaps A. fischeri Reichb., A. maximum Pall. ex DC., and/or A. sachalinense Fr. Schm.; and on the Kuril Islands, A. maximum Pall. ex DC. Poison from the Japanese stingray Dasyatis akajei (Müller et Henle) (aikor chiep) was also much used, alone or mixed with aconite, and was believed by some Ainu to be better than aconite. Adjuvants to these poisons were numerous and varied in each locality. Daphne kamtschatica Maxim. var. yezoensis (Maxim.) Ohwi (ketuhas) was used in hunting walrus. The use of Cynanchum caudatum (Miq.) Maxim. (penup) enabled birds to be caught. Juglans ailanthifolia Carr (nesko) was a fish poison. A critical evaluation of the accounts by Krasheninnikov, Steller, Harms, and others, indicates that the inhibitants of the Kamchatka Peninsula, the Kamchadal (Itelmen), hunted with a poison derived from Aconitum maximum Pall. ex DC. This same species was almost certainly used in the Aleutian Islands and the Kodiak Island region, principally for hunting whales. There is some evidence that the inhabitants of the far north-eastern part of Siberia and of the Alaskan coasts opposite may also have used poison in hunting. The chemistry and toxicology of the poisons are briefly considered.

Aconitum↗
PubMed1984

Microfracture patterns of abrasive wear striations on teeth indicate directionality.

A method is described that will indicate the direction that an abrasive particle was traveling as it scored the surface of a brittle material. Light and scanning electron micrographs of glass, dentine, and enamel abraded by loose and, steel carbide, and diamond indicate that partial Hertzian fracture cones are formed at the margins of wear striations during abrasion. The bases of these fracture cones face in the direction of travel of the abrasive particle and, therefore, indicate directionality. Because this method is based only on the consistent geometry of fracturing of brittle materials, it is independent of the loading of the abrasive particle. The only other method available to determine directionality of striations is unreliable since it uses the width of striations, and, hence, is dependent upon a consistent loading regime of the abrasive particle. This new method has direct application for determining the direction of movement of the jaws during mastication in living or fossil animals.

Animals↗