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Female-biased mortality has been consistently reported in Pacific salmon during their adult upriver migration. We collected coho salmon ( Oncorhynchus kisutch (Walbaum, 1792)) upon arrival at their spawning grounds to test whether females are more prone to cardiac oxygen limitations following exercise stress. We used a surgical approach to periodically sample arterial and venous blood over 48 h following recovery from a chase protocol to induce maximum metabolic rate. We found no significant differences in arterial or venous partial pressures of O2 between males and females. Female salmon had significantly elevated plasma cortisol levels but there were no effects of sex on either plasma lactate or K+. Our data show that female coho salmon do not suffer oxygen limitations to the spongy myocardium after a single exercise event at moderate temperatures (14 °C)—at least not when arriving to their spawning grounds. This study found no clear support for a cardiac oxygen limitation underlying elevated female mortality in Pacific salmon. Neither, however, does our study design nor specific findings allow us to rule out cardiac limitations in these fish. Future work should address whether potential oxygen limitations to the spongy myocardium at high temperatures or oxygen limitations to the compact myocardium via coronary blood flow contribute to female-biased mortality earlier on the migratory route.

Chinook salmon ( Oncorhynchus tshawytscha (Walbaum, 1792)) from the upper Yukon River are highly unique, with some populations migrating nearly 3000 km to spawning habitat near the northern range limit for the species. We conducted a 4-year study to understand the behaviour of Chinook salmon in the terminal reaches of their migration by tagging salmon with acoustic and radio transmitters in Whitehorse, Yukon, Canada, ∼2800 km from the ocean. Various migration characteristics were quantified for Chinook salmon, including en route mortality, diel behaviour, migration rates, and homing patterns, and associations with salmon origin (wild vs. hatchery), sex, size, and migration timing were explored. Salmon had high survival to spawning grounds (>98%) and migrated throughout all hours of the day, with higher proportions of nighttime movements in a smaller spawning tributary than in the Yukon River mainstem. Migration rates were faster for larger salmon as well as late-arriving salmon, which was likely necessary to ensure they had sufficient time and suitable conditions on spawning grounds to reproduce. Non-direct homing movements (e.g., tributary exploration) were more common in male salmon and considerably increased migration distance through the study area. Findings from this study may help to inform the complex international and inter-nation management of these increasingly threatened Chinook salmon populations.

Natural resource governance is inherently complex owing to the socio-ecological systems in which it is embedded. Working arrangements have been fundamentally transformed throughout the COVID-19 pandemic with potential negative impacts on trust-based social networks foundational to resource management and transboundary governance. To inform development of a post-pandemic new-normal in resource management, we examined trust relationships using the Laurentian Great Lakes of North America as a case study. 82.9% (n = 97/117) of Great Lakes fishery managers and scientists surveyed indicated that virtual engagement was effective for maintaining well-established relationships during the pandemic; however, 76.7% (n = 89/116) of respondents indicated in-person engagement to be more effective than virtual engagement for building and maintaining trust. Despite some shortcomings, virtual or remote engagement presents opportunities, such as: (1) care and nurturing of well-established long-term relationships; (2) short-term (1-3 years) trust maintenance; (3) peer-peer or mentor-mentee coordination; (4) supplemental communications; (5) producer-push knowledge dissemination; and, if done thoughtfully, (6) enhancing diversity, equity, and inclusion. Without change, pre-pandemic trust-based relationships foundational to cooperative, multinational, resource management are under threat.

Inland fisheries assessment and management are challenging given the inherent com- plexity of working in diverse habitats (e.g., rivers, lakes, wetlands) that are dynamic on organisms that are often cryptic and where fishers are often highly mobile. Yet, technoscience is offering new tools that have the potential to reimagine how inland fisheries are assessed and managed. So-called ‘‘technoscience’’ refers to instances in which science and technology unfurl together, offering novel ways of spurring and achieving meaningful change. This paper considers the role of technoscience and its potential for modernizing the assessment and management of inland fisheries. It first explores technoscience and its potential benefits, followed by presentation of a series of synopses that explore the application (both successes and challenges) of new tech- nologies such as environmental DNA (eDNA), genomics, electronic tags, drones, phone apps, iEcology, and artificial intelligence to assessment and management. The paper also considers the challenges and barriers that exist in adopting new technologies. The paper concludes with a provocative assessment of the potential of technoscience to reform and modernize inland fisheries assessment and management. Although these tools are increasingly being embraced, there is a lack of platforms for aggregating these data streams and providing managers with actionable information in a timely manner. The ideas presented here should serve as a catalyst for beginning to work collectively and collaboratively towards fisheries assessment and management systems that harness the power of technology and serve to modernize inland fisheries management. Such transformation is urgently needed given the dynamic nature of environmental change, the evolving threat matrix facing inland waters, and the complex behavior of fishers. Quite simply, a dynamic world demands dynamic fisheries management; technoscience has made that within reach.

Hardening of natural shorelines in urban aquatic ecosystems can result in a loss of fish habitat and productivity. The north shore of Toronto Harbour (Lake Ontario) has been converted to hardened boat slips for commercial, industrial and recreational purposes, but its potential utility as fish habitat has not been evaluated. The objective of this study was to determine whether fish frequented and utilized four slips in the inner harbour of Toronto. Two western boat slips are adjacent to some natural features and have undergone some rehabilitation to increase the complexity of aquatic habitat (i.e. addition of large substrate, overhead cover, and in-water structure). In contrast, the two eastern slips are deeper and more influenced by the turbid Don River. We assessed the timing and duration of occupancy within all four slips for seven fish species using acoustic telemetry. In just under a year, tagged fishes spent a limited amount of time in any one slip. However, there was evidence for increased use at the two western slips by Northern Pike (Esox lucius) in spring, which is likely linked to the proximity of these slips to a known spawning area. Overall, there was no reliable evidence that the majority of the seven adult fish species evaluated frequented either the western or eastern slips. Despite efforts to track and tag a variety of species, insufficient detections prevented a detailed assessment of habitat selection for the majority of species of interest. A more detailed study of the spatial ecology of these fishes is therefore needed to understand the scale of their habitat use and inform the design of habitat rehabilitation projects for hardened shorelines.

Parasite load significantly impacts host health and fitness and may vary substantially among individuals within a population. The immunocompetence handicap hypothesis posits that sexual signals are honest indicators of male quality because they are maintained by testosterone, an immunosuppressant that yields higher parasite loads. Additionally, testosterone may influence parasite load by increasing activity levels. We examined these two hypotheses in a wild population of Yarrow’s Spiny Lizards (Sceloporus jarrovii Cope, 1875) in Arizona. We (i) compared fecal testosterone levels to ectoparasite and haemoparasite loads, (ii) tested if sexual signals (total coloured area, aggression, and head size), locomotor activity, and body size correlated with testosterone levels, and (iii) compared sexual signals, locomotor activity, and body size to parasite load. Ectoparasite loads increased with total coloured area and tended to increase with testosterone, but this latter relationship was only nearly significant. Parasite loads increased with body size. Thus, we found some support for the immunocompetence handicap hypothesis and none for the activity hypothesis. Our results are consistent with an alternative hypothesis that larger individuals have more parasites because they have more surface area and (or) have had longer to accumulate parasites. Future studies should examine the relative contributions of testosterone and glucocorticoids in driving variation in parasite loads.

Although inland and marine environments, their fisheries, fishery managers, and the realm-specific management approaches are often different, there are a surprising number of similarities that frequently go unrecognized. We contend that there is much to be gained by greater cross-fertilization and exchange of ideas and strategies between realms and the people who manage them. The purpose of this paper is to provide examples of the potential or demonstrated benefits of working across aquatic boundaries for enhanced sustainable management of the world's fisheries resources. Examples include the need to (1) engage in habitat management and protection as the foundation for fisheries, (2) rethink institutional arrangements and management for open-access fisheries systems, (3) establish "reference points" and harvest control rules, (4) engage in integrated management approaches, (5) reap conservation benefits from the link to fish as food, and (6) reframe conservation and man- agement of fish to better engage the public and industry. Cross-fertilization and knowledge transfer between realms could be realized using environment-independent curricula and symposia, joint scientific advisory councils for management, integrated development projects, and cross-realm policy dialogue. Given the interdependence of marine and inland fisheries, promoting discussion between the realms has the potential to promote meaningful advances in managing global fisheries. Resume : Si les milieux interieur et marin, ainsi que leurs peches et leurs gestionnaires des peches et les approches de gestion propres achacun sont dans bien des cas differents, ils partagent neanmoins de nombreuses similitudes qui, bien souvent, ne sont pas reconnues. Nous arguons qu'il y a beaucoup agagner de la fertilisation croisee et du partage d'idees et de strategies entre ces deux grands domaines et les personnes qui les gerent. L'article a pour but de presenter des exemples d'avantages potentiels ou demontres decoulant des efforts intersectoriels en matiere de peche pour une meilleure gestion durable des ressources halieu- tiques mondiales. Parmi ces exemples figurent la necessite (1) de considerer la gestion et la protection de l'habitat comme constituant les fondements de la peche, (2) de repenser les dispositions et la gestion institutionnelles pour les systemes de peches aacces libre, (3) d'etablir des « points de reference » et des regles visant le controle de l'exploitation, (4) d'adopter des approches de gestion integree, (5) de tirer parti des avantages en matiere de conservation qui decoulent du lien avec les poissons comme source de nourriture et (6) de recadrer la conservation et la gestion des poissons pour mieux mobiliser le public et l'industrie. La fertilisation croisee et le transfert de connaissances entre les domaines pourraient se faire en utilisant des cursus et des symposiums sans egard au milieu, des conseils scientifiques consultatifs conjoints pour la gestion, des projets de mise en valeur integres et un dialogue sur les politiques auquel participeraient des acteurs des deux grands domaines. Etant donne l'interdependance des peches marines et interieures, la promotion des echanges entre ces deux domaines pourrait favoriser des avancees significatives dans la gestion des peches mondiales. (Traduit par la Redaction)

Sexual dimorphism in fishes may be obvious during the reproductive period and less clear during the nonreproductive periods. Despite being difficult to discern during the nonreproductive period, sex-related differences in body condition and shape can yield important insights into a species’ behaviour and ecology. The purpose of this study was to test hypotheses about body condition and shape variation related to sex and season (nonreproductive and reproductive periods) in a population of adult adfluvial bull trout (Salvelinus confluentus (Suckley, 1859)), which is a poorly understood and imperiled species across much of its range. Geometric morphometric samples were collected by angling in the spring and late summer in a reservoir in British Columbia. Principal components analysis identified two principal components (PC) that were related to body condition and that varied according to season and sex. Spring-caught females were in better body condition than spring-caught males. There was a significant sex × season interaction on body condition such that late-summer males were not different from late-summer females. Spawning bull trout exhibited a decline in body condition during the summer season. An additional PC that described head size was found to vary significantly between sexes; however, an assignment test showed that it failed to reliably distinguish between the sexes. We hypothesized that the ecology of these animals, including sex-specific behaviour, is responsible for sexual and seasonal differences in bull trout body condition and morphology. This study offers new insight into the ecology of bull trout and shows that shape data for fishes can be obtained nonlethally, which is particularly important for species that are imperiled.

Knowledge of the reproductive biology of wild sturgeon populations is critical to ensure the survival of this unique group of animals. We combined gill-netting surveys, nonlethal blood sampling, radiotelemetry, and egg collection to examine the reproductive biology of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) at a suspected spawning ground below a dam on the Richelieu River, Quebec. Lake sturgeon were present at the beginning of sampling in early May, and spawning took place from 26 May to 5 June when water temperature averaged 13.4 ± 0.1 °C (range 11.5–15.5 °C). Daily spawning population estimates ranged from 285 to 1282 individuals and the sex ratio of spawners was estimated at 2.1 males per female. The presence of radio-tagged individuals on the spawning grounds peaked from 20 to 28 May, corresponding with known spawning bouts. Residence time of spawners on the spawning ground ranged from 1 to 27 days (median = 5 days) and there were no differences in residence time between sexes. Nonlethal blood sampling enabled the quantification of steroid levels to determine the spawning population sex ratio, and steroid levels were highest before spawning was known to occur and decreased concurrently with, and after, known spawning events.

We evaluate the utility of an inexpensive, portable recovery bag designed to facilitate recovery of fish from capture stress by combining physiological assays, biotelemetry, and social science surveys. Adult migrating Pacific salmon (Oncorhynchus spp.) were used as a model, since some of their populations are threatened. While catch-and-release is common, there is a need to ensure that it is sustainable. A social science survey revealed that anglers generally have positive attitudes towards recovery bag use, particularly if research identifies that such techniques could be effective. Physiological assays on pink salmon (Oncorhynchus gorbuscha) revealed benefits of both high- and low-velocity recovery, but high velocity was most effective with reduced plasma cortisol concentrations and similar plasma sodium and chloride concentrations as those found in controls at all recovery durations. A biotelemetry study on sockeye salmon (Oncorhynchus nerka) captured by anglers and stressed by air exposure then placed in recovery bags had 20% higher, but not significantly different, survival than no-recovery salmon. The integration of natural science and social science provides an important step forward in developing methods for promoting recovery of fish from capture. Resume : Nous evaluons l'utilite d'un sac de recuperation portable et peu dispendieux pour ce qui est de favoriser la recuperation de poissons apres un stress de capture, en combinant des essais physiologiques, des donnees de biotelemetrie et des etudes sociologiques. Des saumons du Pacifique (Oncorhynchus spp.) adultes en migration ont ete utilises comme modele etant donne que certaines de leurs populations sont menacees et que, bien que la peche avec remise al'eau soit repandue, il importe de verifier qu'il s'agit d'une pratique durable. Une etude sociologique a revele que les pecheurs ala ligne voient generalement d'un bon œil l'utilisation d'un sac de recuperation, en particulier si la recherche etablit l'efficacite de telles methodes. Des essais physi- ologiques sur des saumons roses (Oncorhynchus gorbuscha) ont revele que la recuperation tant ahaute vitesse qu'abasse vitesse presentait des avantages, mais que la recuperation ahaute vitesse etait plus efficace, se traduisant par une reduction des concentrations de cortisol plasmatique et des concentrations semblables de sodium et de chlorure, utilisees comme temoins, pour toutes les durees de recuperation. Dans une etude biotelemetrique, des saumons sockeye (Oncorhynchus nerka) captures par des pecheurs ala ligne et soumis au stress de l'exposition al'air, puis places dans des sacs de recuperation presentaient un taux de survie de 20 % superieur acelui des saumons n'ayant pas recupere, bien que cette difference ne soit pas significative. L'integration des sciences naturelles et de la sociologie a donc permis une importante avancee dans la mise au point de methodes favorisant la recuperation de poissons suite aleur capture. (Traduit par la Redaction)

Human immunodeficiency virus type 1 (HIV-1) Nef is important for viral infectivity and pathogenicity. HIV-1 infection is associated with inappropriate activation and defects in the function of monocytes/macrophages. We have studied the effects of HIV-1 Nef in the murine (RAW264.7) and human (THP-1) monocyte-macrophage cell lines. Investigation of the activator protein-1 (AP-1) transcription factor showed that Nef expression induced both its DNA binding and transcriptional activities. Increased AP-1 DNA binding activity in RAW264.7 cells was associated with raised levels of c-Fos expression and induction of mRNA for the AP-1 responsive tissue inhibitor of metalloproteinases-1 (TIMP-1) gene. Mutagenesis and kinase inhibition studies were employed to determine signaling pathways used by Nef to induce AP-1. Data from these studies indicated that induction of AP-1 by Nef is likely to be mediated through the MAPK (ERK1 and 2) signaling pathway and requires the proline-rich PxxP motif of Nef, suggesting the involvement of upstream protein kinases belonging to the Src family. Effects of Nef on AP-1 induction were cell lineage-specific, being stimulatory in macrophages, inhibitory in T cells and without effect in HeLa cells. These latter two observations led us to test the possibility that cell-specific interactions of Nef with Src family proteins may modulate AP-1 activity. To this end we demonstrated that a dominant-negative Hck mutant caused inhibition of Nef-mediated AP-1 DNA binding activity in RAW cells. In conclusion, induction of AP-1 by Nef is a specific feature of human and murine macrophage cell lines that requires signal transduction events involving Hck and MAPKs.

The gene coding for the major inner capsid protein VP6 of human group C rotavirus was cloned into baculovirus using the pBlueBac2 vector and expressed in insect cells. When cultured in High Five cells, VP6 was expressed at a high level and exported to the cell culture medium. Purified VP6 was used to immunise rabbits. Hyperimmune rabbit serum, which reacted with native human group C rotavirus in infected cells, was used to develop and optimise an EIA for the detection of antibodies to group C rotavirus using the recombinant VP6 as a source of antigen. In a local epidemiological survey of 1000 sera grouped by age, an average of 43% of samples were found to have antibodies to human group C rotavirus with the highest proportion (66%) in the 71-75 year age group. In comparison, 97% of adults and 85% of children had antibodies to recombinant VP6 from the bovine RF strain of group A rotavirus. These results suggest that infection with human group C rotavirus is a common occurrence despite the apparent rarity of reports of human group C rotavirus in clinical samples from patients with gastroenteritis.

Animal models have illustrated that a carbon dioxide (CO(2)) pneumoperitoneum can cause a rise in intracranial pressure (ICP). This study investigated key symptoms and signs of raised ICP in 39 patients after laparoscopic abdominal surgery and compared them with a control group of 33 patients after open operations. The findings show that the incidence of headache and nausea was significantly higher in the laparoscopic group than in the control subjects. End-tidal CO(2) levels were recorded, and no significant difference was found between patients and control subjects. We conclude that these results could be explained by raised intracranial pressure exacerbated by the CO(2) pneumoperitoneum, and that this effect is not mediated by raised expiratory CO(2) levels intraoperatively.

The surface plasmon resonance measurement technique has been enhanced by improved accuracy of measurement and speed of analysis. By this means, separate determination of thickness and refractive index information is possible even for monolayer films. A computer-controlled, angle-scan reflectometer for internal reflectance measurement by prism coupling has been calibrated by a novel method to eliminate systematic errors and reduce noise below 0.04%. The instrument has been used for characterisation, of thin dielectric films deposited using the Langmuir-Blodgett method. The Levenberg-Marquardt optimisation algorithm has been applied using a simple model for rapid assessment of film parameters. An analysis of multilayer films of behenic acid has exhibited excellent consistency of measurement down to a single molecular monolayer. A refractive index of 1.55 ± 0.01 and a layer thickness of 2.65 nm are found and layer quality is assessed from scattering losses. A molecular tilt angle of 26° is deduced from comparison with a molecular model, and is in agreement with infrared spectroscopic data. A monolayer film of an organo-ruthenium complex molecule has been analysed to assess film thickness and quality.

A novel, sequence-independent strategy has been developed for the amplification of full-length cDNA copies of the genes of double-stranded RNA (dsRNA) viruses. Using human (Bristol) group C rotavirus as an example, a single amino-linked modified oligonucleotide (primer 1) was ligated to either end of each dsRNA genome segment by using T4 RNA ligase. Following reverse transcription, annealing, and repair of cDNA strands, amplification of the viral dsRNA genome was accomplished by polymerase chain reaction using a single complementary oligonucleotide (primer 2). Northern (RNA) hybridization of cDNA to virus dsRNA indicated that it was possible to generate cDNA representing the complete genome from very small clinical samples. This technique was used to determine the complete nucleotide sequence (728 bp) and coding assignment of gene 10, which revealed an open reading frame of 212 amino acids with limited homology to NS26 from human group A rotavirus. In contrast to previous tailing methods, the addition of one defined primer allowed unequivocal identification of terminal nucleotides and should be generally applicable to viruses with segmented dsRNA genomes and especially for analysis of clinical samples, for which very limited quantities of biological material are available.

The VP6 gene of human group C rotavirus was cloned and sequenced. Hybridization to the human group C and the porcine group C/Cowden dsRNA genomes assigned this coding sequence to segment 5. The complete human VP6 sequence contained an open reading frame of 1185 nucleotides (395 amino acids; deduced Mr 44,669 Da). The protein sequence demonstrated low homology with the group A VP6 sequences (41.7 to 42.7%) and high homology (88.9%) with the porcine group C VP6 sequence. However, the protein sequence alignments revealed a region of 10 amino acids that were significantly different between the human and the porcine group C viruses.

Summary form only given. We describe a new 3D electromagnetic simulation code capable of fast, accurate modeling of both resonant cavities and slow-wave structures. We also present results of a new method to obtain complete dispersion properties for a 3D coupled-cavity TWT structure based on analysis of only the computed /spl pi/- and 2/spl pi/-modes. The underlying electromagnetic algorithm uses the finite element method on an unstructured conformal mesh, with both quadratic elements and quadratic basis functions to rapidly achieve a high degree of accuracy. For example, the /spl pi/-mode frequency of a coupled-cavity: TWT can be determined to 0.1% accuracy in 2-3 minutes on a 2 GHz PC. To determine dispersion curves for a coupled-cavity TWT, we model a chain of cavities using an open-mode expansion method. Fields in each cavity are represented as a linear combination of a small set of precomputed /spl pi/- and 2/spl pi/-eigenmode fields of the cavity, so that just a few mode amplitudes represent the complete 3D field. Coupling between adjacent cavities is calculated using a set of integrals over the cavity interfaces, derived directly from Maxwell's equations. This formulation allows us to obtain a small matrix representation for the complete system that may be solved directly, for either the discrete modes of a chain of cavities or by applying a Floquet boundary condition to reduced representation of a single cavity. Results of this method are compared to experimental data. The core code has been written in object-oriented C++ for high performance, but most of the functionality is made directly available from within the Python language. This provides a simple yet highly flexible interface for specifying problem data, such as boundary conditions or material properties, or for automating complex calculations. At present, the mesh is imported from a commercial mesh generation tool, supporting a CAD interface, though a variety of mesh file formats are supported.

Summary form only given. The Cold Test and Large Signal Simulation (CTLSS) eigenmode solver, developed by SAIC, has been used to model the dispersion and impedance characteristics of a Northrop Grumman X-Band helix TWT. Helix geometry complicates the solution for solvers of this type due to the fact that the objects being modeled, circular backwall and helix as well as rectangular dielectric rods, do not easily lend themselves to accurate representation by any one coordinate system. This is further complicated by the fact that helix geometry is axially periodic and therefore solution times can become quite long since an entire pitch period must be modeled to allow for the correct periodicity of the helical system. Measured dispersion and impedance data from a Northrop Grumman X-Band TWT is being used to benchmark the results generated by CTLSS for helix geometry. A GUI is included with the CTLSS distribution which generates a CTLSS input file for any type of geometry desired. Several templates are available for common structures including helix TWTs, coupled-cavity TWTs, and klystron cavities. The GUI allows one to easily modify the size and shape of individual components as well as set or modify numerical parameters necessary for solution. A visualization toolkit is also provided with the CTLSS distribution which allows one to view the resulting CTLSS structure. This allows for verification of the physical layout of the structure being modeled. A separate option displays the computed eigenmode fields in 3D contour format. Comments on use of both the CTLSS GUI and visualization toolkit will be presented. CTLSS can be run on both UNIX and PC platforms. Both platforms have been used for this study and will be compared. Information on setup times will be included as well as solution times. Proper gridding is always important when setting up problems of this type. Many different approaches can be used to determine the optimum grid features to allow for the most accurate representation of the physical structures involved. A discussion of some of these approaches as well as the features of the helical system which most strongly affect the computed results will be given. Interaction impedance is an important input parameter for modeling of the beam/RF interaction of any helix TWT and determines the coupling of the individual electron macroparticles, rings, or discs to the RF wave traveling on the surrounding helix. Once the eigenmodes have been computed, this interaction impedance can be determined by integrating the axial electric field along the axis of the helical system. This quantity has been experimentally determined for the X-Band TWT using a perturbation method and an automated phase measurement system. The results of the comparison of measurement and CTLSS calculation will be presented.

Summary form only given, as follows. To measure the radiated power from a high power millimeter wave device it is preferable to perform calorimetry. A calorimeter has been designed and tested for measurements on a 35 GHz gyroklystron amplifier experiment at NRL. The output radiation is in the form of a TE/sub 01/ circular waveguide mode in a highly overmoded guide (operating frequency is more than three times cutoff). The final calorimeter design is an inverted cone structure with power absorption by octyl alcohol. Low radiation reflection, mode conversion, and extraneous heat dissipation are obtained. Three levels of analysis are performed. A simple ray tracing theory allows reflection coefficient and mode conversion to be found by replacing the symmetric circular mode with an equivalent rectangular one. A finite difference code based on a planar circuit analysis provides the same information with a more rigorous treatment of the rectangular boundary conditions. Finally, HFSS simulations are carried out for a restricted number of candidate designs using the actual circular structure. Cold test results will be described in additions to details of the calorimeter construction and calibration.

Amino acid sequence alignments between the human group C/Bristol and the published porcine group C/Cowden VP6 proteins have revealed a region of extreme sequence divergence. We have been unable to confirm the nucleotide sequence of the Cowden VP6 gene corresponding to this region of divergence. Direct sequencing of a PCR-amplified cDNA pool has revealed a frame shift, and three nucleotide changes, within the published sequence of the porcine (Cowden) VP6 gene. The corrected sequence of the porcine protein revealed a closer homology with VP6 from the Bristol strain and two new human group C rotavirus isolates. Atypical rotaviruses have been detected in the feces of children living in Belem, Brazil, and Preston, U.K. Direct sequencing of PCR-amplified cDNA corresponding to the VP6 gene of one isolate from each location confirmed the presence of a group C rotavirus. The complete nucleotide sequences of the VP6 genes from the group C/Belem and C/Preston rotaviruses contained an open reading frame of 1185 nucleotides (395 amino acids; deduced M(r) 44,669 Da). The Belem VP6 gene demonstrated 97.9% nucleotide homology with the human group C/Bristol VP6 gene and 83.4% nucleotide homology (91.6% deduced amino acid homology) with the corrected porcine group C/Cowden sequence. The Preston VP6 gene demonstrated 99.6% nucleotide homology with the human group C/Bristol VP6 gene and 84.0% nucleotide homology (91.6% deduced amino acid homology) with the corrected porcine group C/Cowden sequence. Remarkably, the deduced amino acid sequence of the Brazilian strain was identical to that of the U.K. isolates.