The Erie Canal in western New York state provides water to many streams during the summer and is a potential source of invasive species, such as the Zebra Mussel (Dreissena polymorpha). Yet the Zebra Mussel is not found in those streams except immediately downstream from where canal water enters them. Given appropriate physical habitat, water quality and an abundant source of veliger larvae, the factors limiting Zebra Mussel colonization in the stream we studied remain unknown, but three factors appear to be important: 1) Partial retention of veligers by the wetland through which the canal discharge flows, 2) Filtering of phytoplankton and veligers by the dense bed of adult Zebra Mussels at the beginning of the outfall channel from the canal to the creek, or 3) Inappropriate food quality (e.g., lack of phytoplankton with important fatty acid constituents) in the creek.

In the fall of 1982, 15 radio-tagged Pacific Salmon exhibited typical pre-spawning and spawning movements in Lake Ontario and several of its tributaries. There were no significant differences in daily and hourly movement rates between Coho Salmon (Oncorhynchus kisutch) and Chinook Salmon (O. tshawytscha). Salmon homed strongly to streams where they had been stocked 2-3 years earlier (64%); correlations between precipitation events and movements in the lake, stream entries and stream exits were low (r < 0.27; and angler mortality among fish entering tributaries was high (78%).

Benthic macroinvertebrate communities were quantified at natural cobble and artificial reef sites in Lake Ontario in 1983 (7 y pre-Dreissena invasion) and in 1991-1992 and 1999-2000 (1-2 and 9-10 y post-Dreissena invasion, respectively). Overall, the natural cobble community had higher species diversity and community abundance than the artificial reef community. While taxonomic composition of both communities remained consistent during the study period, organism abundance (excluding Dreissena) increased sharply from 1983 to 1991-1992, and that all taxa declined to 1983 levels by 1999-2000. From 1991-1992 to 1999-2000, Dreissena bugensis, which mostly replaced D. polymorpha, and Echinogammarus ischnus (all invasive species) appeared in the studied community. We conclude that the transition from D. polymorpha to D. bugensis and processes associated with the ongoing oligotrophication of Lake Ontario are responsible for the reduced density of large-bodied Dreissena in the nearshore region of the lake, and that changes in the Dreissena population are largely responsible for changes in the non-Dreissena benthic macroinvertebrate community.

SUNY Brockport collaborated with Monroe County, New York to assess fish communities in three tributaries of Braddock Bay with different development histories: Northrup Creek, Larkin Creek and Buttonwood Creek.

Macroinvertebrate communities were compared in dredged and undredged areas of the St. Lawrence River near Cape Vincent, N. Y., by sampling with a Ponar dredge in spring, summer and fall seasons. Total macroinvertebrate abundance was greater in undredged areas. Differences in total invertebrate abundance and relative abundance of individual species in dredged and undredged areas appear to be related to the presence of gyttja-type sediments caused by breakwater construction and dredging operations at least 40 years ago.

Expression of vascular smooth muscle cell (VSMC) markers such as serum response factor (SRF) is complicated in zebrafish because of the ill-defined histology of the dorsal aorta and the presence of perivascular pigment. We report the ultrastructure of aortic cells in 7-day, 1-month, and 3-month-old zebrafish and provide clear evidence for the presence of perivascular melanocytes harboring an abundance of melanin. In 7-day-old larvae, endothelial cells (EC) and synthetic mural cells that display little evidence of VSMC differentiation comprise the dorsal aorta. The latter mural cells appear to fully differentiate into VSMC by 1 month of age. In 3-month-old adult zebrafish, EC exhibit greater differentiation as evidenced by the accumulation of electron-dense bodies having a diameter of approximately 200 nm. Adult zebrafish aortae also exhibit at least one clear layer of VSMC with the characteristic array of membrane-associated dense plaques, myofilament bundles, and a basement membrane. Subjacent to VSMC are collagen-producing adventitial fibroblasts and melanocytes. These studies indicate that fully differentiated VSMC occur only after day 7 in zebrafish and that such cells are arranged in at least one lamellar unit circumscribing the endothelium. These findings provide new data about the timing and accumulation of VSMC around the zebrafish aorta, which will be useful in phenotyping mutant zebrafish that exhibit defects in blood circulation.

The protein enhancer of rudimentary homolog, ERH, is a small, highly conserved protein that has been found in animals, plants, and protists. Genetic and biochemical interactions have implicated ERH in the regulation of pyrimidine biosynthesis, DNA replication, transcription, mRNA splicing, cellular proliferation, tumorigenesis, and the Notch signaling pathway. In vertebrates and insects, ERH is nuclearly localized; however, an examination of the ERH amino-acid sequence does not reveal any nuclear localization signals. In this paper we show that the first 24 amino acids contain sequences necessary and sufficient for nuclear localization. Through yeast two-hybrid screens, three new binding partners of ERH, RPS3, RPL19, andDDIT4,were identified. RPS3 was isolated from both human and Drosophila screens. These interactions suggest functions of ERH in cell growth, cancer, and DNA repair. The ERH sequences necessary for the interactions between ERH and RPS3 and RPL19 are mapped onto the same 24-amino-acid region in ERH which are necessary for nuclear localization, suggesting that ERH is localizing to the nucleus through binding to one of its DNA-binding partners, such as RPS3 or RPL19.

T-type Ca2+ currents have been detected in cells from the external muscular layers of gastrointestinal smooth muscles and appear to contribute to the generation of pacemaker potentials in interstitial cells of Cajal from those tissues. However, the Ca2+ channel subunit responsible for these currents has not been determined. We established that the ? subunit of the ?1H Ca2+ channel is expressed in single myocytes and interstitial cells of Cajal using reverse transcription and polymerase chain reaction from whole tissue, laser capture microdissected tissue and single cells isolated from the mouse jejunum. Whole-cell voltage clamp recordings demonstrated that a nifedipine and Cd2+ resistant, mibefradil-sensitive current is present in myocytes dissociated from the jejunum. Electrical recordings from the circular muscle layer demonstrated that mibefradil reduced the frequency and initial rate of rise of the electrical slow wave. Gene targeted knockout of both alleles of the cacna1h gene, which encodes the ? 1H Ca2+ channel subunit, resulted in embryonic lethality because of death of the homozygous knockouts prior to E13.5 days in utero. We conclude that a channel with the pharmacological and molecular characteristics of the ? 1H Ca2+ channel subunit is expressed in interstitial cells of Cajal and myocytes from the mouse jejunum, and that ionic conductances through the ? 1H Ca2+ channel contribute to the upstroke of the pacemaker potential. Furthermore, the survival of mice that do not express the ? 1H Ca2+ channel protein is dependent on the genetic background and targeting approach used to generate the knockout mice.