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PubMed1967

Effects of Phosfon-S on Nucleic Acid Metabolism in Pisum sativum Alaska.

Phosfon-S, a substance which inhibits stem elongation, alters nucleic acid metabolism in Pisum sativum Alaska. Methylated albumin kieselguhr (MAK) columns were used to fractionate (32)P-labeled nucleic acids. Phosfon-S treatment of the plants resulted in a decrease in soluble RNA and an increase in ribosomal RNA. Specific activities of the various nucleic acid fractions were lower as a result of treatment. The nucleic acids from treated tissues were more resistant to RNase degradation, and endogenous RNase activity was lower in treated tissues. When RNase treated nucleic acids were fractionated on MAK columns, the DNA-RNA fractions from treated plants had a higher specific activity than that of the control, which was not true before nuclease treatment. Spectrophotometric examination of this fraction revealed a difference in absorption spectra, possibly indicating a Phosfon-S nucleic acid complex. It is suggested that these alterations in nucleic acid metabolism could in turn alter a wide variety of metabolic processes, resulting in retarded growth.

Journal Article↗
PubMed1971

Pyrimidine metabolism in cotyledons of germinating alaska peas.

Cotyledons from Pisum sativum L. cv. Alaska seeds were excised 12, 36, 108, 132, and 156 hours after imbibition in aerated distilled water. They were then incubated under aseptic conditions for 6 hours in solutions containing either uridine-2-(14)C or orotic acid-6-(14)C. Uridine was more extensively degraded to (14)CO(2) at all germination stages than was orotate, and these rates remained essentially constant at each stage. Incorporation of each compound into RNA increased about 2-fold from the 12th to the 156th hour, although the total RNA present decreased slightly over this interval. Paper chromatography of soluble labeled metabolites produced from orotate showed that the capacity to metabolize this pyrimidine increased markedly as germination progressed. Radioactivity in uridine-5'-P, uridine diphosphate-hexoses, and uridine diphosphate increased most, while smaller or less consistent increases in uridine, uracil, uridine triphosphate, and an unidentified UDPX compound were also observed. The data suggest that orotate metabolism was initially limited by orotidine-5'-phosphate pyrophosphorylase or by 5-phosphoribosyl-1-pyrophosphate. Incorporation of uridine into RNA appeared to be limited at the earliest germination periods by conversion of uridine-5'-P to uridine diphosphate. Thus, during the 1st week of germination the orotic acid pathway and a salvage pathway converting uridine into RNA become activated.

Journal Article↗
PubMed1971

In vivo phytochrome reversion in immature tissue of the alaska pea seedling.

Reversion of far red-absorbing phytochrome to red-absorbing phytochrome without phytochrome destruction (that is, without loss of absorbancy and photoreversibility) occurs in the following tissues of etiolated Alaska pea seedlings (Pisum sativum L.): young radicles (24 hours after start of imbibition), young epicotyls (48 hours after start of imbibition), and the juvenile region of the epicotyl immediately subjacent to the plumule in older epicotyls. Reversion occurs rapidly in the dark during the first 30 minutes following initial phototransformation of red-absorbing phytochrome to far red-absorbing phytochrome. If these tissues are illuminated continuously with red light for 30 minutes, the total amount of phytochrome remains unchanged. Beyond 30 minutes after a single phototransformation or after the start of continuous red irradiation, phytochrome destruction commences. In young radicles, sodium azide inhibits this destruction, but does not affect reversion. In older tissues in which far red-absorbing phytochrome destruction begins immediately upon phototransformation, strong evidence for simultaneous far red-absorbing phytochrome reversion is obtained from comparison of far red-absorbing phytochrome loss in the dark following a single phototransformation with far red-absorbing phytochrome loss under continuous red light.

Journal Article↗
PubMed1978

Rapidly Induced Wound Ethylene from Excised Segments of Etiolated Pisum sativum L., cv. Alaska: I. Characterization of the Response.

A rapidly induced, transitory increase in the rate of ethylene synthesis occurred in wounded tissue excised from actively growing regions of etiolated barley, cucumber, maize, oat, pea, tomato, and wheat seedlings. Cutting intact stems or excising 9-mm segments of tissue from near the apex of 7-day-old etiolated Pisum sativum L., cv. Alaska seedlings induced a remarkably consistent pattern of ethylene production. At 25 C, wound-induced ethylene production by segments excised 9 mm below the apical hook increased linearly after a lag of 26 minutes from 2.7 nanoliters per g per hour to the first maxium of 11.3 nanoliters per g per hour at 56 minutes. The rate of production then decreased to a minimum at 90 minutes, increased to a lower second maximum at 131 minutes, and subsequently declined over a period of about 100 minutes to about 4 nanoliters per g per hour. Removal of endogenous ethylene, before the wound response commenced, had no effect on the kinetics of ethylene production. Tissue containing large amounts of dissolved ethylene released it as an exponential decay with no lag period. Rapidly induced wound ethylene is synthesized by the tissue and is not merely the result of facilitated diffusion of ethylene already present in the tissue through the newly exposed cut surfaces. Previously wounded apical sections did not exhibit a second response when rewounded. No significant correlation was found between wound-induced ethylene synthesis and either CO(2) or ethane production.

Journal Article↗
PubMed1978

Rapidly Induced Wound Ethylene from Excised Segments of Etiolated Pisum sativum L., cv. Alaska: II. Oxygen and Temperature Dependency.

Wound-induced ethylene synthesis by subapical stem sections of etiolated Pisum sativum L., cv. Alaska seedlings, as described by Saltveit and Dilley (Plant Physiol 1978 61: 447-450), was half-saturated at 3.6% (v/v) O(2) and saturated at about 10% O(2). Corresponding values for CO(2) production during the same period were 1.1% and 10% O(2), respectively. Anaerobiosis stopped all ethylene evolution and delayed the characteristic pattern of wound ethylene synthesis. Exposing tissue to 3.5% CO(2) in air in a flow-through system reduced wound ethylene synthesis by 30%. Enhancing gas diffusivity by reducing the total pressure to 130 mm Hg almost doubled the rate of wound ethylene synthesis and this effect was negated by exposure to 250 mul liter(-1) propylene. Applied ethylene or propylene stopped wound ethylene synthesis during the period of application, but unlike N(2), no lag period was observed upon flushing with air. It is concluded that the characteristic pattern of wound-induced ethylene synthesis resulted from negative feedback control by endogenous ethylene.No wound ethylene was produced for 2 hours after excision at 10 or 38 C. Low temperatures prolonged the lag period, but did not prevent induction of the wound response, since tissue held for 2 hours at 10 C produced wound ethylene immediately when warmed to 30 C. In contrast, temperatures above 36 C prevented induction of wound ethylene synthesis, since tissue cooled to 30 C after 1 hour at 40 C required 2 hours before ethylene production returned to normal levels. The activation energy between 15 and 36 C was 12.1 mole kilocalories degree(-1).

Journal Article↗
PubMed1978

Rapidly Induced Wound Ethylene from Excised Segments of Etiolated Pisum sativum L., cv. Alaska: III. Induction and Transmission of the Response.

Increased ethylene synthesis was rapidly induced throughout the apical meristematic region of etiolated seedlings of Pisum sativum L., cv. Alaska by cuts made 1 centimeter from the apical hook. The wound signal was transmitted at about 2 millimeters per minute. Accumulation of substance(s) at the cut surfaces of excised sections, as the result of interrupted translocation, did not initiate or significantly contribute to wound-induced ethylene synthesis, nor was the cut surface the site of enhanced ethylene synthesis. Cutting subapical sections into shorter pieces showed that cells less than 2 millimeters from a cut surface produced about 30% less ethylene than cells greater than 2 millimeters from a cut surface.

Journal Article↗
PubMed1979

Studies of Rapidly Induced Wound Ethylene Synthesis by Excised Sections of Etiolated Pisum sativum L., cv. Alaska: IV. Requirement of a Water-soluble, Heat-stable Factor.

The rate of wound ethylene synthesis was reduced by more than 85% when 9-millimeter subapical sections of etiolated 7-day-old Pisum sativum L., cv. Alaska seedlings were incubated in water during the 26-minute induction period prior to wound ethylene synthesis, but the rate of synthesis was unaffected if sections were incubated in water during the actual synthesis of wound ethylene. The characteristic timing of the wound response was unaffected by either treatment. The ability of various chemical solutions and aqueous plant extracts to alter the rate of wound ethylene synthesis was studied by first incubating subapical pea stem sections in solutions under anaerobic conditions (anaerobiosis delays the induction and synthesis of wound ethylene; Plant Physiol 61: 675-679), and then measuring wound ethylene synthesis after the tissue was transferred to air. Solutions of several reported precursors of ethylene synthesis, such as methionine, homoserine, or propanal, did not reverse the water-caused reduction of wound ethylene synthesis. A water-soluble, heat-stable factor in extracts from pea seedlings, and solutions of 23 nanomolar triacontanol, 10 micromolar kinetin, or 10 micromolar benzyladenine prevented the reduction of wound ethylene synthesis, but were ineffective if administered after an initial 15-minute anaerobic water incubation. This suggested that the active solutions may have only prevented the loss of some ephemeral, though necessary factor, rather than actually containing the substrate or inducer of wound ethylene synthesis. Attempts to isolate and characterize the active fraction from aqueous tissue extracts were unsuccessful. Free radical quenchers, inhibitors of protein synthesis, and rhizobitoxine, an inhibitor of ethylene synthesis from methionine, all reduced wound ethylene synthesis when administered in solutions which previously had maintained wound ethylene synthesis.

Journal Article↗
PubMed1982

Physiology of Movements in Stems of Seedling Pisum sativum L. cv. Alaska : I. Experimental Separation of Nutation from Gravitropism.

Gravitropism and nutation in the stems of dark-grown, seedling peas (Pisum sativum L. cv. Alaska) were recorded on time-lapse photographs made with photomorphogenetically inactive light. Although gravitropism and nutation have been connected by several different theories in the past, our experiments indicate that the two processes are in fact dissociable. The evidence is as follows: (a) Nutational patterns are asymmetric. There is much greater amplitude of oscillation in the plane parallel ( parallel) to the plane of the apical hook than in the plane perpendicular ( perpendicular), yet the average gravitropic response is equal in these two planes. (b) Brief red light irradiation given 16 to 24 hours before observation greatly increases the amplitude of nutation in the parallel-plane, but has no influence on the kinetics of gravitropic response. (c) An inhibitor of auxin transport, alpha-naphthylphthalamic acid, strongly inhibits nutation at 5 micromolar but affects gravitropism only at higher concentrations. (d) Nutation is also strongly inhibited by removal of the apical bud, but gravitropism is unaffected. (e) The period of nutation does not exhibit a constant relationship to the response time of gravitropism. The above evidence is inconsistent with theories that gravitropism is an asymmetrically modified nutation or, alternatively, that nutational oscillations result in a simple fashion from gravitropic overshoots. The evidence is consistent with, although not proof of, autonomous factors such as an endogenous rhythm of growth as the cause of nutation in pea stems. However, gravity and nutation do interact. Nutation in a population of seedlings can be synchronized and brought into phase by a single gravitropic induction. Furthermore, the response time and initial rate of gravitropic curvature depend to some extent on the phase of nutational curvature at which gravitropic induction is begun.

Journal Article↗
PubMed1983

Physiology of Movements in the Stems of Seedling Pisum sativum L. cv Alaska : III. Phototropism in Relation to Gravitropism, Nutation, and Growth.

Phototropic response in etiolated pea (Pisum sativum L. cv Alaska) seedlings is poor. However, the curvature induced by unilateral blue light can be hastened and increased in magnitude by a previously administered red light pulse followed by several hours of darkness. Phytochrome is involved in the red light effect. Phototropic response was almost completely inhibited by removal of the apical bud and hook, but it was restored if exogenous indole-3-acetic acid was applied apically to the cut stump. Therefore, the stem contains both the phototropic photoreceptor and response mechanism. Perception of gravity and gravitropic response were also localized in the stem, but gravitropism was scarcely inhibited by decapitation. It was also observed that the kinetics and curvature pattern of gravitropism differed greatly from those of phototropism. Like phototropism, stem nutation required auxin and was promoted by red light. Unlike phototropism, photoenhanced nutational curvature required the apical hook and was propagated as a wave down the stem. Naphthylphthalamic acid inhibited, in order of decreasing effect, nutation, phototropism/gravitropism, and growth. Phototropism, gravitropism, and nutation appear to represent distinct forms of stem movement with fundamental differences in the mechanisms of curvature development.

Journal Article↗
PubMed1992

Behavior of Etiolated Peas (Pisum sativum cv Alaska) When Obstructed by a Mechanical Barrier.

Etiolated pea (Pisum sativum cv Alaska) seedlings growing against a horizontal barrier in the soil will assume a horizontal orientation and continue to grow for prolonged periods of time. With removal of the barrier or after seedlings grow out from underneath the obstruction, seedlings immediately return to normal vertical growth. Ethylene production increased several hours after the seedlings began to grow horizontally and not at the first contact with a barrier. Increases in ethylene production from horizontally growing seedlings were associated with decreased rates of elongation and increased stem diameter. The data suggest that increased ethylene production does not play a mediating role in the horizontal growth of pea seedlings when obstructed during emergence. We conclude that seedlings follow a path of least resistance when they grow against a barrier in the soil.

Journal Article↗
PubMed1996

Midline congenital anomalies: the estimated occurrence among American Indian and Alaska Native infants.

While congenital anomalies have been identified as the second leading cause of infant mortality among American Indians and Alaska Natives, limited information exists concerning the morbidity of such malformations. This study was undertaken to address this concern. Using data from the national hospital discharge database of the Indian Health Service, for the years 1980-1988, morbidity rates of seven, relatively common and easily identifiable midline malformations among liveborn infants in this minority population were estimated. The seven congenital anomalies and the estimated rates per 10000 births were: neural tube defects 8.09; oral clefts 29.03; abdominal wall defects 2.99; tracheoesophageal fistula 1.86; conotruncal heart defects 5.90; rectal atresia 3.15; and diaphragmatic hernia 3.24. Seven cases (1.1%) had two midline defects reported.

Cleft Lip↗
PubMed2006

Endometrial adenocarcinoma and mucometra in a 6-year-old Alaska Malamute dog.

A 6-year-old female Alaska Malamute dog was presented for evaluation of abdominal enlargement referred by a local veterinarian. On the history, the owner complained of chronic abdominal enlargement initiated more than 4 months ago, reduced appetite, occasional vomiting and general dullness. He also complained of greenish mucous intermittent vaginal discharge starting 10 days ago. The bitch was chronically treated with medroxiprogesterone acetate. A laparatomy was performed and fluid in the abdomen was found and aspirated during the surgery. Also a very fluid-filled distended uterus and a mass in the distal part of the left uterine horn were found. The mass was encapsulated by the omentum, but areas of necrosis and calcification were identified. Histopathological diagnosis was endometrial adenocarcinoma.

Adenocarcinoma↗
PubMed2005

Periodically triggered seismicity at Mount Wrangell, Alaska, after the Sumatra earthquake.

As surface waves from the 26 December 2004 earthquake in Sumatra swept across Alaska, they triggered an 11-minute swarm of 14 local earthquakes near Mount Wrangell, almost 11,000 kilometers away. Earthquakes occurred at intervals of 20 to 30 seconds, in phase with the largest positive vertical ground displacements during the Rayleigh surface waves. We were able to observe this correlation because of the combination of unusually long surface waves and seismic stations near the local earthquakes. This phase of Rayleigh wave motion was dominated by horizontal extensional stresses reaching 25 kilopascals. These observations imply that local events were triggered by simple shear failure on normal faults.

Journal Article↗
PubMed1984

Evidence for a terpene-based food chain in the gulf of alaska.

A mixture of C-terpenes was prepared from conifer seedlings and introduced into fresh seawater samples taken near Seward, Alaska. Initial rates of oxidation by the indigenous bacteria were linear and faster than the rates of toluene oxidation. Turnover times were 4 to 19 days. Autoradiographic measurements with H-terpenes indicated that at least 10% of the 0.6 x 10 to 2.7 x 10 bacteria per liter present could catabolize terpenes. The rate of terpene oxidation, 24 mug of terpenes per g of cells per h with 3 mug of terpenes added per liter, was a constant function of bacterial biomass. The specific affinity of the process was estimated to be between 8.1 and 81 liters/g of cells per h, indicating a high state of induction and the probable presence of terpenes. Terpene-oxidizing bacteria were grown on [C]alanine and added to fresh seawater samples. Transfer of the bacterial radioactivity into larger particles at a rate of 146 pg/liter per h from the 2.3 x 10 organisms added indicated that any terpenes present would participate in the food chain.

Journal Article↗
PubMed1984

Seismic stress effects on vegetative and reproductive development of 'Alaska' pea.

Vegetative and reproductive growth responses of pea (Pisum sativum L. cv. Alaska) to periodic seismic (shaking) stress were investigated during fall, winter, and spring seasons in a greenhouse. Growth changes caused by equivalent shaking treatment varied quantitatively among seasons, with the least response occurring during winter, but they were qualitatively similar during all three seasons. Shaking caused significant reduction in all growth parameters measured except root dry weight and leaf number after 16 days of treatment. Reproductive growth responses to shaking (occurring from 16 to 35 days of treatment) included delay of anthesis but no difference in number of fruits set after as much as 35 days of treatment. Seismic stress significantly reduced the number but not the weight of individual seeds per pod. Mean relative shoot growth rate was reduced by shaking during reproductive as well as vegetative growth. During both periods of development this response was caused almost entirely by inhibition of net carbon assimilation rate.

Environment, Controlled↗
PubMed2005

American Indians and Alaska Natives in California: women's cancer screening and results.

BACKGROUND AND METHODS: The purpose of this article was to examine differences in demographics, general health status, and utilization of breast and cervical cancer screening for subgroups of American Indians and Alaska Natives (AIAN) using the 2001 California Health Interview Survey. RESULTS: The statewide distribution of California American Indians, non-California AIANs, and unknown AIANs are 10%, 51%, and 39%, respectively. Significant differences exist among the 3 tribal subgroups. CONCLUSIONS: Overall, AIAN women aged 40+ years are close to the Healthy People 2010 goals for receipt of a mammogram in the past 2 years and for receipt of a Pap test ever and in the past 3 years. Less than 5% of AIAN in California report Indian Health Service coverage.

Adolescent↗
PubMed2005

What is the role of diet in the development of cancer in American Indian and Alaska native populations?

BACKGROUND: The associations between diet and cancer in American Indian and Alaska Native (AIAN) populations are not well understood. METHODS: I review current knowledge of the associations between diet and cancer. RESULTS: Studies of diet and cancer are inconsistent. Underlying characteristics of populations could contribute to observed differences. Dietary patterns and energy balance may importantly relate to cancer in AIAN populations. CONCLUSION: Given the differences in cancer incidence and mortality rates in AIAN populations, it is reasonable that diet and lifestyle patterns could contribute to these differences, although we can only speculate as to specific dietary factors in cancer etiology.

Cultural Characteristics↗
PubMed2006

"It's not that simple": A collaborative comparison of sea ice environments, their uses, observed changes, and adaptations in Barrow, Alaska, USA, and Clyde River, Nunavut, Canada.

The Arctic environment, including sea ice, is changing. The impacts of these changes to Inuit and Iñupiat ways of life vary from place to place, yet there are common themes as well. The study reported here involved an exchange of hunters, Elders, and others from Barrow, Alaska, USA, and Clyde River, Nunavut, Canada, as members of a larger research team that also included visiting scientists. Although the physical environments of Barrow and Clyde River are strikingly different, the uses of the marine environment by residents, including sea ice, had many common elements. In both locations, too, extensive changes have been observed in recent years, forcing local residents to respond in a variety of ways. Although generally in agreement or complementary to one another, scientific and indigenous knowledge of sea ice often reflect different perspectives and emphases. Making generalizations about impacts and responses is challenging and should therefore be approached with caution. Technology provides some potential assistance in adapting to changing sea ice, but by itself, it is insufficient and can sometimes have undesirable consequences. Reliable knowledge that can be applied under changing conditions is essential. Collaborative research and firsthand experience are critical to generating such new knowledge.

Adaptation, Physiological↗