Regulation of brood size in a burying beetle,Nicrophorus tomentosus (Silphidae)

Regulation of brood size in a biparental burying beetle, Nicrophorus tomentosusWeber, was studied by providing pairs with one of two sizes of mouse carcasses in the laboratory. For a given carcass size, there was an inverse relationship between number and mass offspring in a brood. The requirement for regulation was that brood size was adjusted such that mean mass of individual larvae was constant for carcasses of different size. Brood size was regulated if parents were present but regulation did not occur if parents were removed prior to hatching of larvae. Pairs bred in quick succession on two carcasses raised fewer than the regulated number of young in the second reproductive attempt. Reasons for regulation of brood size in this genus are discussed.     

Acute post-irradiation canine intestinal blood flow

Radiation-induced early transient incapacitation (ETI) is accompanied by severe systemic hypotension, during which arterial blood pressure often decreases to less than 50 per cent of normal. One haemodynamic compensatory mechanism is increased peripheral resistance due to vasoconstriction. This vasoconstriction in the small intestine of dogs is disproportionately increased during haemorrhagic or endotoxic shock, and intestinal ischaemia is frequent. In an attempt to elucidate mechanisms underlying radiation-induced ETI and the gastrointestinal radiation syndrome, canine intestinal submucosal blood flow was measured by the hydrogen polarographic technique, both before and after exposure to gamma radiation. Systemic blood pressures, blood gases and haematocrits were determined simultaneously. Data obtained from 12 sham-irradiated dogs and 12 irradiated dogs indicated that 90 Gy, whole-body, gamma radiation produced a 31 per cent decrease in systemic mean blood pressure beginning within 20 min post-irradiation and lasting for at least 90 min. However, the intestinal submucosal blood flow did not decrease as anticipated, but it exhibited an actual post-irradiation increase. This increase in post-irradiation intestinal submucosal blood flow began within 5 min after irradiation and lasted for at least 90 min. Post-irradiation haematocrits were 10.5 per cent higher than those obtained before irradiation and those obtained from sham-irradiated subjects. Histopathological examination of ileal mucosa revealed significant pathologic lesions in some irradiated animals within two hours after exposure.     

A Field Evaluation of an External and Neutrally Buoyant Acoustic Transmitter for Juvenile Salmon: Implications for Estimating Hydroturbine Passage Survival

Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if this new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System) used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT) tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm) downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss) to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days) single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to confirm this.     

Rangewide landscape genetics of an endemic Pacific northwestern salamander

A species' genetic structure often varies in response to ecological and landscape processes that differ throughout the species' geographic range, yet landscape genetics studies are rarely spatially replicated. The Cope's giant salamander (Dicamptodon copei) is a neotenic, dispersal‐limited amphibian with a restricted geographic range in the Pacific northwestern USA. We investigated which landscape factors affect D. copei gene flow in three regions spanning the species' range, which vary in climate, landcover and degree of anthropogenic disturbance. Least cost paths and Circuitscape resistance analyses revealed that gene flow patterns vary across the species' range, with unique combinations of landscape variables affecting gene flow in different regions. Populations in the northern coastal portions of the range had relatively high gene flow, largely facilitated by stream and river networks. Near the southeastern edge of the species' range, gene flow was more restricted overall, with relatively less facilitation by streams and more limitation by heat load index and fragmented forest cover. These results suggested that the landscape is more difficult for individuals to disperse through at the southeastern edge of the species' range, with terrestrial habitat desiccation factors becoming more limiting to gene flow. We suggest that caution be used when attempting to extrapolate landscape genetic models and conservation measures from one portion of a species' range to another.     

Development of advanced host cell protein enrichment and detection strategies to enable process relevant spike challenge studies

An orthogonal chromatography methodology for the enrichment of host cell protein (HCP) species relative to monoclonal antibody (mAb) products was developed and applied for the successful enrichment of HCP from post‐Protein A process pools for seven different mAb products. An advanced two‐dimensional liquid chromatography/mass spectrometry platform (2D‐LC/MS^E) was utilized to demonstrate that the HCP enriched material was representative, in terms of species content, to pre‐enriched process pools. The HCP enrichment methodology was scaled up for two different mAb products, and this process relevant enriched HCP material was used to conduct advanced spike challenge studies to demonstrate the utility of the approach for the understanding of (1) quantitative HCP clearance, (2) individual species clearance, and (3) species clearance redundancy across polishing chromatography steps. The combined ability to enrich process relevant HCP, detect individual HCP species with 2D‐LC/MS^E technology, and conduct advanced challenge studies with process relevant material surmounts prior limitations to high integrity process challenge study implementation, and facilitates significant process understanding for development of risk‐based control strategies and strategic process design. This also demonstrates implementation of a foundational strategy for conducting spike‐challenge studies using process‐relevant impurities isolated from processes of interest using orthogonal approaches. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:983–989, 2015     

Interaction of nucleic acids with Coomassie Blue G-250 in the Bradford assay

The Bradford assay has been used reliably for decades to quantify protein in solution. The analyte is incubated in acidic solution of Coomassie Blue G-250 dye, during which reversible ionic and nonionic binding interactions form. Bradford assay color yields were determined for salmon, bovine, shrimp, and kiwi fruit genomic DNA; baker's yeast RNA; bovine serum albumin (BSA); and hen egg lysozyme. Pure DNA and RNA bound the dye, with color yields of 0.0017mg(-1)cm(-1) and 0.0018mg(-1)cm(-1), respectively. The nucleic acid-Coomassie Blue response was significant, at roughly 9% of that for BSA and 18% of that for lysozyme.     

Juvenile hormone-mediated reproduction in burying beetles: From behavior to physiology

The burying beetle, Nicrophorus orbicollis, is the first beetle exhibiting parental care for which endocrinological studies have been initiated. Burying beetles bury and prepare small vertebrate carcasses as a breeding resource for their offspring. After emergence as an adult, hemolymph titers of juvenile hormone and ovarian size increase in concert for 2–3 weeks, and both plateau until an appropriate resource is discovered. Upon finding a suitable carcass, titers of juvenile hormone increase extremely rapidly (<20 min), and within 18 h ovarian mass increases threefold and oviposition begins. This rapid reproductive development is hypothesized to be selected by the intense competition for these protein-rich but quickly deteriorating resources. Burying beetle females exhibit an additional juvenile hormone surge at the time young hatch. This peak in juvenile hormone is hypothesized to be associated with either the considerable behavioral demands which accompany care of young larvae or with a female's willingness to oviposit a replacement clutch should brood failure occur early in the care-giving phase. Parental care has evolved in at least 16 additional families within the Coleoptera. Comparative studies of nonparental and parental groups will be important for understanding how the physiology of ancestral groups affects the evolution of complex social behavior. Arch. Insect Biochem. Physiol. 35:479–490, 1997. © 1997 Wiley-Liss, Inc.     

Improving hydroturbine pressures to enhance salmon passage survival and recovery

Barotrauma caused by rapid decompression during hydroturbine (turbine) passage may occur as fish move through the low pressure region below the turbine runner. This scenario is of particular concern in North American rivers with populations of ESA-listed salmon. The US Army Corps of Engineers (USACE) and the Pacific Northwest National Laboratory released Sensor Fish into lower Snake and Columbia River turbines to determine the magnitude and rate of pressure change fish might experience. Recorded pressures were applied to simulated turbine passage (STP) in laboratory studies to determine the effect of rapid decompression on juvenile Chinook salmon. These STP studies have increased our understanding of how pressure effects fish passing through turbines and suggest that the ratio of pressure change [acclimation pressure (the depth upstream of the dam where fish are neutrally buoyant) divided by nadir pressure (lowest pressure)] is highly predictive in determining the effect on smolt survival. However, uncertainty remains in smolt acclimation depth prior to entering turbine intakes at hydroelectric facilities. The USACE continues to make progress on salmon survival and recovery efforts through continued research and by applying pressure study results to turbine design. Designing new turbines with higher nadir pressure criteria is likely to provide safer fish passage for all salmonid species experiencing turbine passage.