Status,trends, and equilibrium abundance estimates of the translocated sea otter population in Washington State

Sea otters (Enhydra lutris kenyoni) historically occurred in Washington State, USA, until their local extinction in the early 1900s as a result of the maritime fur trade. Following their extirpation, 59 sea otters were translocated from Amchitka Island, Alaska, USA, to the coast of Washington, with 29 released at Point Grenville in 1969 and 30 released at La Push in 1970. The Washington Department of Fish and Wildlife has outlined 2 main objectives for sea otter recovery: a target population level and a target geographic distribution. Recovery criteria are based on estimates of population abundance, equilibrium abundance (K), and geographic distribution; therefore, estimates of these parameters have important management implications. We compiled available survey data for sea otters in Washington State since their translocation (1977–2019) and fit a Bayesian state-space model to estimate past and current abundance, and equilibrium abundance at multiple spatial scales. We then used forward projections of population dynamics to explore potential scenarios of range recolonization and as the basis of a sensitivity analysis to evaluate the relative influence of movement behavior, frontal wave speed, intrinsic growth, and equilibrium density on future population recovery potential. Our model improves upon previous analyses of sea otter population dynamics in Washington by partitioning and quantifying sources of estimation error to estimate population dynamics, by providing robust estimates of K, and by simulating long-term population growth and range expansion under a range of realistic parameter values. Our model resulted in predictions of population abundance that closely matched observed counts. At the range-wide scale, the population size in our model increased from an average of 21 independent sea otters (95% CI = 13–29) in 1977 to 2,336 independent sea otters (95% CI = 1,467–3,359) in 2019. The average estimated annual growth rate was 12.42% and varied at a sub-regional scale from 6.42–14.92%. The overall estimated mean K density of sea otters in Washington was 1.71 ± 0.90 (SD) independent sea otters/km² of habitat (1.96 ± 1.04 sea otters/km², including pups), and estimated densities within the current range correspond on average to 87% of mean sub-regional equilibrium values (range = 66–111%). The projected value of K for all of Washington was 5,287 independent sea otters (95% CI = 2,488–8,086) and 6,080 sea otters including pups (95% CI = 2,861–9,300), assuming a similar range of equilibrium densities in currently un-occupied habitats. Sensitivity analysis of simulations of sea otter population growth and range expansion suggested that mean K density estimates in currently occupied sub-regions had the largest impact on predicted future population growth (r² = 0.52), followed by the rate of southward range expansion (r² = 0.26) and the mean K density estimate of currently unoccupied sub-regions to the south of the current range (r² = 0.04). Our estimates of abundance and sensitivity analysis of simulations of future population abundance and geographic range help determine population status in relation to population recovery targets and identify the most influential parameters affecting future population growth and range expansion for sea otters in Washington State.     

Emerging technology for fermenting d-xylose

In the past four years, numerous yeasts which convert d-xylose to ethanol have been reported. The conversion occurs most readily under aerobic conditions. Various aspects of this conversion have provided new insight into the mechanisms and metabolic regulation of ethanol fermentation in yeasts. Although specific fermentation rates, product yields and product concentrations are significantly lower with d-xylose than with d-glucose, technology is emerging which may prove to be feasible for commercial fermentation of d-xylose-containing waste streams.     

DNA barcoding of microgastrine parasitoid wasps (Hymenoptera: Braconidae) using high‐throughput methods more than doubles the number of species known for Australia

The Microgastrinae are a hugely diverse subfamily of endoparasitoid wasps of lepidopteran caterpillars. They are important in agriculture as biological control agents and play a significant ecological role in the regulation of caterpillar populations. Whilst the group has been the focus of intensive rearing and DNA barcoding studies in the Northern Hemisphere, the Australian fauna has received little attention. In total, 99 species have been described from or have been introduced into Australia, but the real species diversity for the region is clearly much larger than this. In this study, museum ethanol samples and recent field collections were mined for hundreds of specimens of microgastrine wasps, which were then barcoded for the COI region, ITS2 ribosomal spacer and the wingless nuclear genes, using a pooled sequencing approach on an Illumina Miseq system. Full COI sequences were obtained for 525 individuals which, when combined with 162 publicly available sequences, represented 417 haplotypes, and a total of 236 species were delimited using a consensus approach. By more than doubling the number of known microgastrine wasp species in Australia, our study highlights the value of DNA barcoding in the context of employing high‐throughput sequencing methods of bulk ethanol museum collections for biodiversity assessment.     

Effects of environmental conditions on production of xylitol byCandida boidinii

Candida boidinii NRRL Y-17213 produced more xylitol thanC. magnolia (NRRL Y-4226 and NRRL Y-7621),Debaryomyces hansenii (C-98 M-21, C-56 M-9 and NRRL Y-7425), orPichia (Hansenula) anomala (NRRL Y-366). WithC. boidinii, highest xylitol productivity was at pH 7 but highest yield was at pH 8, using 5 g urea and 5 g Casamino acids/I. Decreasing the aeration rate decreased xylose consumption and cell growth but increased the xylitol yield. When an initial cell density of 5.1 g/l was used instead of 1.3 g/l, xylitol yield and the specific xylitol production rate doubled. Substrate concentration had the greatest effect on xylitol production; increasing xylose concentration 7.5-fold (to 150 g/l) gave a 71-fold increase in xylitol production (53 g/l) and a 10-fold increase in xylitol/ethanol ratio. The highest xylitol yield (0.47 g/g), corresponding to 52% of the theoretical yield, was obtained with 150 g xylose/l after 14 days. Xylose at 200 g/l inhibited xylitol production.E. Vandeska and S. Kuzmanova were and S. Amartey and T. Jeffries are with the Forest Products Laboratory, Institute for Microbial and Biochemical Technology, 1 Gifford Pinchot Drive, Madison, WI 53703, USA. E. Vandeska and S. Kuzmanova are now with the Faculty of Technology and Metallurgy, Rudjer Boskovic 16, 91000 Skopje, Macedonia     

Chemical inactivation of HIV on surfaces.

To assess whether alcohol and glutaraldehyde are effective disinfectants against dried HIV the virucidal effects of 70% alcohol (ethanol and industrial methylated spirit) and 1% and 2% alkaline glutaraldehyde were tested against cell associated and cell free HIV dried on to a surface. Virus stock (100 microliters) or 10,000 cultured C8166 T lymphocytes infected with HIV were dried onto sterile coverslips and immersed in 2% and 1% alkaline glutaraldehyde and 70% ethanol for 30 seconds and one, two, four, and 10 minutes, there being an additional time point of 20 minutes for cell free virus disinfected with 70% industrial methylated spirit. In addition, virus stock in neat serum was tested with 1% and 2% alkaline glutaraldehyde to see whether the fixative properties of glutaraldehyde impair its virucidal properties. Virus activity after disinfection was tested by incubating the coverslips (cell associated virus) or the coverslips and sonicated cell free virus with C8166 T lymphocytes. The lymphocytes were examined for the formation of syncytia and HIV antigens were assayed in the culture fluid. Both 2% and 1% alkaline glutaraldehyde inactivated cell free HIV within one minute; 2% alkaline glutaraldehyde also inactivated cell free virus in serum within two minutes, but a 1% solution was ineffective after 15 minutes'' immersion. Cell associated HIV was inactivated by 2% alkaline glutaraldehyde within two minutes. Seventy per cent industrial methylated spirit failed to inactivate cell free and cell associated HIV within 20 and 15 minutes, respectively, and 70% ethanol did not inactivate cell free virus within 10 minutes. Seventy per cent industrial methylated spirit and ethanol are not suitable for surface disinfection of HIV. Fresh 2% solutions of alkaline glutaraldehyde are effective, but care should be taken that they are not too dilute or have not become stale when used for disinfecting HIV associated with organic matter.     

A catalytic 13-mer ribozyme.

A 13-mer oligoribonucleotide can act as a ribozyme for the specific self-cleavage of a 41-mer oligoribonucleotide substrate in the presence of Mg2+. The two sequences involved correspond to the self-cleavage hammerhead structure of the virusoid of lucerne transient streak virus. The Michaelis-menten kinetic parameters for the reaction were; Km 1.3 microM, Vmax 0.012 microM min-1, kcat 0.5 min-1. The 13-mer RNA is the smallest ribozyme so far reported. A DNA analogue of the 13-mer can not substitute for the RNA in the reaction.     

ATP-induced dissociation of rabbit skeletal actomyosin subfragment 1. Characterization of an isomerization of the ternary acto-S1-ATP complex

The adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S) induced dissociation of actomyosin subfragment 1 (S1) has been investigated by monitoring the light scattering changes that occur on dissociation. We have shown that ATP gamma S dissociates acto-S1 by a mechanism similar to that of ATP but at a rate 10 times slower. The maximum rate of dissociation is limited by an isomerization of the ternary actin-S1-nucleotide complex, which has a rate of 500 s-1 for ATP gamma S and an estimated rate of 5000 s-1 for ATP (20 degrees C, 0.1 M KCl, pH 7.0). The activation energy for the isomerization is the same for ATP and ATP gamma S, and both show a break in the Arrhenius plot at 5 degrees C. The reaction between acto-S1 and ATP was also followed by the fluorescence of a pyrene group covalently attached to Cys-374. We show that the fluorescence of the pyrene group reports the isomerization step and not actin dissociation. The characterization of this isomerization is discussed in relation to force-generating models of the actomyosin cross-bridge cycle.