November 2007: National American Indian & Alaska Native Heritage Month

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Active-site properties of Phrixotrix railroad worm green and red bioluminescence-eliciting luciferases

The luciferases of the railroad worm Phrixotrix (Coleoptera: Phengodidae) are the only beetle luciferases that naturally produce true red bioluminescence. Previously, we cloned the green- (PxGR) and red-emitting (PxRE) luciferases of railroad worms Phrixotrix viviani and P. hirtus[OLE1]. These luciferases were expressed and purified, and their active-site properties were determined. The red-emitting PxRE luciferase displays flash-like kinetics, whereas PxGR luciferase displays slow-type kinetics. The substrate affinities and catalytic efficiency of PxRE luciferase are also higher than those of PxGR luciferase. Fluorescence studies with 8-anilino-1-naphthalene sulfonic acid and 6-p-toluidino-2-naphthalene sulfonic acid showed that the PxRE luciferase luciferin-binding site is more polar than that of PxGR luciferase, and it is sensitive to guanidine. Alutagenesis and modelling studies suggest that several invariant residues in the putative luciferin-binding site of PxRE luciferase cannot interact with excited oxyluciferin. These results suggest that one portion of the luciferin-binding site of the red-emitting luciferase is tighter than that of PxGR luciferase, whereas the other portion could be more open and polar.

Molecular insights on the evolution of the lateral and head lantern luciferases and bioluminescence colors in Mastinocerini railroad-worms (Coleoptera: Phengodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The influence of the region between residues 220 and 344 and beyond in Phrixotrix railroad worm luciferases green and red bioluminescence

To find the regions having a major influence on the bioluminescence spectra of railroad worm luciferases, we constructed new chimeric luciferases switching the fragments from residues 1-219 and from 220-545 between Phrixotrix viviani (PxvGR; λmax = 548 nm) green light-emitting luciferase and Phrixothrix hirtus (PxhRE; λmax = 623 nm) red light-emitting luciferases. The emission spectrum (λmax = 571 nm) and KM for luciferin in the chimera PxRE220GR (1-219, PxhRE; 220-545, PxvGR) suggested that the region above residue 220 of PxvGR had a major effect on the active site. However, switching the sequence between the residues 226-344 from PxvGR luciferase into PxhRE (PxREGRRE) luciferase resulted in red light emission (λmax = 603 nm), indicating that the region 220-344 by itself does not determine the emission spectrum. Furthermore, the sequence before residue 220 of the green-emitting luciferase is incompatible for light emission with the sequence above residue 220 of PxhRE. These results suggest that the fragments before and after residue 220, which correspond to distinct subdomains, may fold differently in the green- and red-emitting luciferases, affecting the active site conformation.

Method for estimating railroad track settlements due to dynamic traffic loads

This paper is the result of real-scale physical modeling study designed to simulate the load-deformation characteristics of railroad foundation systems that include the railroad ties, the ballast, and the sub-base layers of a railroad embankment. The study presents comparisons of the application of dynamic loads of 100kN on the rails, and the resulting deformations during a 500,000 cycle testing period for three rail support systems; wood, concrete and steel. The results show that the deformation curve has an exponential shape, with the larger portion of the deformation occurring during the first 50,000 load cycles followed by a tendency to stabilize between 100,000 to 500,000 cycles. These results indicate that the critical phase of deformations of a new railroad is within the first 50,000 cycles of loading, and after that, it slowly attenuates as it approaches a stable value. The paper also presents empirically derived formulations for the estimation of the deformations of the rail supports as a result of rail traffic.

Geotechnical and structural behavior of the railroad track in large-scale apparatus

This paper analyses the static and dynamic behavior of the railroad track model in laboratory. Measurements of stresses and strains on a large-scale railroad track apparatus were studied. The model includes: compacted soil, representing the final layers of platform, ballast layer, and ties (steel, wooden, and pre-stressed concrete). The soil and soil ballast interface were instrumented with pneumatic stress gauge. Settlement measurement device were positioned at the same levels as the load cells. Loads were applied by hydraulic actuators, statically and dynamically. After the prescribed number of load cycles, in pre-determined intervals, stresses and strains were measured. Observations indicate that stress and strain distributions, transmitted by wooden or steel ties, behave similarly. A more favorable behavior was observed with pre-stressed concrete mono block ties. Non-linear response was observed after a threshold numbers of cycles were surpassed, showing that the strain modulus increases with the numbers of cycles. © 2009 IOS Press.

A Preliminary Note on Trichinosis Investigations in Alaska

Trichinosis in the arctic regions of the world has received considerable attention during recent years, particularly since the work of Roth (1948) in Greenland. In Connell's (1949) review of arctic trichinosis some Alaskan and Canadian records were included but, until now, little has been known of the status of the disease in Alaska. Information available at the present time indicates that the incidence of trichinosis is high in circumpolar carnivores and that marine mammals have a definite place in its epizootiology. Present knowledge cannot explain the survival of trichinosis in marine mammal populations, but it is evident that they may serve as important sources of human infection. Up to the present time the following mammals from Alaska have been found to be infected: From the arctic coast-polar bear, Thalarctas maritimus; arctic fox, Alapex lagapus irmuitus; red fox, Vulpes fulva alascemis; white whale, Delphinapterus leucas; Eskimo dog. From south of the Brooks Range--brown and grizzly bears, Ursus spp.; wolf, Canis lupus ssp.; wolverine. Gula l. luscus. At the time of writing, nearly ail species of land carnivores in Alaska have been examined as well as many other mammalian species less likely to be infected, including various rodents, shrews, and others.

Notes on the Nunamiut Eskimo and Mammals of the Anaktuvuk Pass Region, Brooks Range, Alaska

Covers the physical attributes (physiography, climate and vegetation) of the Brooks Range, Alaska, as well as the Numamuit Eskimo people who lived there in the 1940s and before (including information about their livelihood, history, dwellings, clothing, food, transportation and hunting implements), and includes a list and description of the mammals that lived there (including shrews, grizzly bears, foxes, wolves, martens, ermines, weasels, minks, wolverines, otters, lynxes, hares, marmots, ground squirrels, red squirrels, lemmings, voles, beavers, porcupines, moose, caribou and sheep).

The Abundance of Harbor Seals in the Gulf of Alaska

The abundance of harbor seals (Phoca vitulina richardii) has declined in recent decades at several Alaska locations. The causes of these declines are unknown, but there is concern about the status of the populations, especially in the Gulf of Alaska. To assess the status of harbor seals in the Gulf of Alaska, we conducted aerial surveys of seals on their haul-out sites in August-September 1996. Many factors influence the propensity of seals to haul out, including tides, weather, time of day, and time of year. Because these “covariates” cannot simultaneously be controlled through survey design, we used a regression model to adjust the counts to an estimate of the number of seals that would have been ashore during a hypothetical survey conducted under ideal conditions for hauling out. The regression, a generalized additive model, not only provided an adjustment for the covariates, but also confirmed the nature and shape of the covariate effects on haul-out behavior. The number of seals hauled out was greatest at the beginning of the surveys (mid-August). There was a broad daily peak from about 1100-1400 local solar time. The greatest numbers were hauled out at low tide on terrestrial sites. Tidal state made little difference in the numbers hauled out on glacial ice, where the area available to seals did not fluctuate with the tide. Adjusting the survey counts to the ideal state for each covariate produced an estimate of 30,035 seals, about 1.8 times the total of the unadjusted counts (16,355 seals). To the adjusted count, we applied a correction factor of 1.198 from a separate study of two haul-out sites elsewhere in Alaska, to produce a total abundance estimate of 35,981 (SE 1,833). This estimate accounts both for the effect of covariates on survey counts and for the proportion of seals that remained in the water even under ideal conditions for hauling out.

Estimating abundance of killer whales in the nearshore waters of the Gulf of Alaska and Aleutian Islands using line-transect sampling

Killer whale (Orcinus orca Linnaeus, 1758) abundance in the North Pacific is known only for a few populations for which extensive longitudinal data are available, with little quantitative data from more remote regions. Line-transect ship surveys were conducted in July and August of 2001–2003 in coastal waters of the western Gulf of Alaska and the Aleutian Islands. Conventional and Multiple Covariate Distance Sampling methods were used to estimate the abundance of different killer whale ecotypes, which were distinguished based upon morphological and genetic data. Abundance was calculated separately for two data sets that differed in the method by which killer whale group size data were obtained. Initial group size (IGS) data corresponded to estimates of group size at the time of first sighting, and post-encounter group size (PEGS) corresponded to estimates made after closely approaching sighted groups.

Cetaceans of Southeast Alaska: Distribution and Seasonal Occurrence

Aim To assess the distribution, group size, seasonal occurrence and annual trends of cetaceans. Location The study area included all major inland waters of Southeast Alaska. Methods Between 1991 and 2007, cetacean surveys were conducted by observers who kept a constant watch when the vessel was underway and recorded all cetaceans encountered. For each species, we examined distributional patterns, group size, seasonal occurrence and annual trends. Analysis of variance (anova F) was used to test for differences in group sizes between multiple means, and Student’s t-test was used to detect differences between pairwise means. Cetacean seasonal occurrence and annual trends were investigated using a generalized linear model framework. Results Humpback whales (Megaptera novaeangliae) were seen throughout the region, with numbers lowest in spring and highest in the fall. Fin whale (Balaenoptera physalus) and minke whale (Balaenoptera acutorostrata) distributions were more restricted than that reported for humpback whales, and the low number of sightings precluded evaluating seasonal trends. Three killer whale (Orcinus orca) eco-types were documented with distributions occurring throughout inland waters. Seasonal patterns were not detected or could not be evaluated for resident and offshore killer whales, respectively; however, the transient eco-type was more abundant in the summer. Dall’s porpoise (Phocoenoides dalli) were distributed throughout the region, with more sightings in spring and summer than in fall. Harbour porpoise (Phocoena phocoena) distribution was clumped, with concentrations occurring in the Icy Strait/Glacier Bay and Wrangell areas and with no evidence of seasonality. Pacific white-sided dolphins (Lagenorhynchus obliquidens) were observed only occasionally, with more sightings in the spring. For most species, group size varied on both an annual and seasonal basis. Main conclusions Seven cetacean species occupy the inland waters of Southeast Alaska, with distribution, group size, seasonal occurrence and annual trends varying by species. Future studies that compare spatial and temporal patterns with other features (e.g. oceanography, prey resources) may help in identifying the key factors that support the high density and biodiversity of cetaceans found in this region. An increased understanding of the region’s marine ecology is an essential step towards ensuring the long-term conservation of cetaceans in Southeast Alaska.

Killer Whale Predation on Belugas in Cook Inlet, Alaska: Implications for a Depleted Population

Killer whale predation on belugas in Cook Inlet, Alaska, has become a concern since the decline of these belugas was documented during the 1990s. Accordingly, killer whale sightings were compiled from systematic surveys, observer databases, and anecdotal accounts. Killer whales have been relatively common in lower Cook Inlet (at least 100 sightings from 1975 to 2002), but in the upper Inlet, north of Kalgin Island, sightings were infrequent (18 in 27 yr), especially prior to the 1990s. Beach cast beluga carcasses with teeth marks and missing flesh also provided evidence of killer whale predation. Most observed killer whale/beluga interactions were in the upper Inlet. During 11 of 15 observed interactions, belugas were obviously injured or killed, either through direct attacks or indirectly as a result of stranding. Assuming at least one beluga mortality occurred during the other four encounters, we can account for 21 belugas killed between 1985 and 2002. This would suggest a minimum estimate of roughly l/yr and does not include at least three instances where beluga calves accompanied an adult that was attacked.

Harbor Porpoise (Phocoena phocoena) Abundance in Alaska: Bristol Bay to Southeast Alaska, 1991-1993

Between 1991 and 1993, Alaska harbor porpoise (Phocoena phocoena) abundance was investigated during aerial surveys throughout much of the coastal and offshore waters from Bristol Bay in the eastern Bering Sea to Dixon Entrance in Southeast Alaska. Line-transect methodology was used, and only those observations made during optimal conditions were analyzed. Survey data indicated densities of 4.48 groups/100 km2, or approximately 3,531 harbor porpoises (95% C.I. 2,206-5,651) in Bristol Bay and 0.54 groups/100 km2, or 136 harbor porpoises (95% C.I. 11-1,645) for Cook Inlet. Efforts off Kodiak Island resulted in densities of 1.85 groups/100 km2, or an abundance estimate of 740 (95% C.I. 259-2,115). Surveys off the south side of the Alaska Peninsula found densities of 2.03 groups/100 km2 and an abundance estimate of 551 (95% C.I. 423-719). Surveys of offshore waters from Prince William Sound to Dixon Entrance yielded densities of 4.02 groups/100 km’ and an abundance estimate of 3,982 (95% C.I. 2,567-6,177). Combining all years and areas yielded an uncorrected density estimate of 3.82 porpoises per 100 km2, resulting in an abundance estimate of 8,940 porpoises (CV = 13.8%) with a 95% confidence interval of 6,746-11,848. Using correction factors from other studies to adjust for animals missed by observers, the total number of Alaska harbor porpoises is probably three times this number.

Evidence of a Feeding Aggregation of Humpback Whales (Megaptera novaeangliae) Around Kodiak Island, Alaska

The known summer feeding range of the North Pacific humpback whale (Megaptera novaeangliae) extends from California, along the coasts of Oregon, Washington, and Alaska, into the Bering Sea, along the Aleutian Islands, the Sea of Okhotsk (Tomilin 1957), and to northern Japan (Rice 1977). In feeding areas of the northeastern Pacific Ocean, humpback whale photoidentification research has been concentrated off California (Calambokidis et al. 1993), southeastern Alaska (Darling and McSweeney 1985, Baker et al. 1986, 1992; Perry et al. 1990), Prince William Sound in Alaska (von Ziegesar 1992), the Oregon and Washington coasts (Calambokidis et al. 1993), and British Columbia (Darling and McSweeney 1985; Graerne Ellis, unpublished data). Results of these photoidentification studies have documented that individual whales tend to return to the same general areas in subsequent years (Darling and McSweeney 1985, Baker et al. 1986, Calambokidis et a(. 1996, von Ziegesar et al. 1994).

Results from the April 2009 Gulf of Alaska Line Transect Survey (GOALS) in the Navy Training Exercise Area

Little is known about the present-day occurrence of cetaceans found in offshore waters in the Gulf of Alaska; however, whaling records and a few recent surveys have shown this area to be important habitat. The U.S. Navy maintains a maritime training area in the central Gulf of Alaska, east of Kodiak Island, and has requested additional information on marine mammal presence and use of this area. To describe the occurrence and distribution of marine mammals in and around the U.S. Navy training area, a line transect visual and acoustic survey was conducted 10-20 April 2009 from the NOAA ship Oscar Dyson. The primary survey area encompassed nearshore and offshore pelagic waters of the central Gulf of Alaska. Survey lines were designed to provide equal coverage of the nearshore and offshore habitat.