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.

The interstitial cells of Cajal (ICCs) are important mediators of gastrointestinal motility due to their role as pacemakers in the GI tract. In addition to their function, ICCs are also structurally distinct cells most easily identified by their ultra-structural features and expression of the tyrosine kinase receptor c-KIT. ICCs have been described in mammals, rodents, birds, reptiles and amphibians ; there are no reports at the ultra-structural level of ICC’s within the GI tract of an organism from the teleost lineage. This report describes the presence of cells in the muscularis of the zebrafish intestine with similar features to ICCs in other vertebrates. ICC-like cells were associated with the muscularis, were more electron dense than surrounding smooth muscle cells, possessed long cytoplasmic processes and mitochondria, and were situated opposing to enteric nervous structures. In addition, immunofluorescent and immunoelectron microscopic studies using antibodies targeting the zebrafish ortholog of a putative ICC marker, c-KIT (kita), demonstrated c-kit immunoreactivity in zebrafish ICCs. Taken together, these data represent the first ultra-structural characterization of cells in the muscularis of the zebrafish Danio rerio and suggest ICC differentiation in vertebrate evolution may date back to the teleost lineage.

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.

The enhancer of rudimentary, e(r), gene encodes a small highly conserved protein, enhancer of rudimentary homolog (ERH), which has been shown to have a regulatory function in cell division, Notch signaling, and cancer progression. Human and Drosophila ERH, both 104 amino acids in length, are 76% identical and 84% similar. The high sequence identity translates into nearly identical tertiary structures. Previous studies on the expression of the human and Drosophila e(r) genes reveal that the two genes are similarly regulated. Data in the present study using an e(r)-eGFP reporter gene confirm these results, showing a high expression of the reporter in the ovaries, testes, and brain. The high structural and regulatory conservation of e(r) and ERH argue that human and Drosophila ERH may be biochemically and functionally equivalent. To test this hypothesis, a chimeric transgene containing the Drosophila e(r) non-coding regions and the human e(r) coding region was constructed and used to establish transgenic Drosophila stocks. This transgene can rescue all of the mutant phenotypes of an e(r) deletion, and Drosophila stocks in which the fly ERH has been replaced with the human ERH are fully healthy and viable. These studies demonstrate that the human and Drosophila ERH are functionally equivalent, suggesting that studies on the activity of the human ERH can be done in Drosophila, where a multitude of genetic and developmental tools are available.