• 3’ Terminal Processing of Precursor tRNA Transcribed From a Drosophila Melanogaster Histidine Gene in a Cell-Free System

      Kline, Larry K.; Fulginiti, James P.; The College at Brockport (1987-01-01)
      Transfer RNA biosynthesis is a complex process which includes trimmings at the 5' and 3' termini and nucleotide modification of the initial tRNA precursor. This research involves the detention and isolation of a 3' endonucleolytic activity from Schizosaccharomyces pombe. tRNA precursors are obtained from a cell-free transcription system using (i) a Drosophila tRNA-histidine gene which contains a 35 base pair trailer sequence at its 3' terminus and (ii) a crude yeast enzyme extract which can faithfully transcribe the gene and process the precursor transcripts. Transcription products are separated by means of polyacryfamide gel electrophoresis visualized by autoradiography, and eluted from the gel. The tRNA precursors are then incubated with a Sc. pombe extract, electrophoresed and autoradiographed. The intact 35 base pair trailer sequence will serve as an indicator of the presence of the 3' endonuclease.
    • A Comparison of Created and Natural Wetlands and the Effect of Landscape Characteristics on Vegetation, Amphibian and Bird Variables in Freshwater Marshes of Upstate New York

      Norment, Christopher; Porter, David W.; The College at Brockport (2006-08-01)
      Wetlands provide a number of ecological and social functions, including flood abatement, improvement of water quality, recharge ground water and support for a great diversity of flora and fauna. Despite their many functions and values, wetlands have not always been appreciated. Since the 1780s, it is estimated that 53% of wetland acreage in the United States has been lost due to draining, filling and the subsequent development of land for roads or farms. In 1972, the Clean Water Act (CWA) was established to try to reverse declining wetland acreage in the U.S. According to Section 404 of the CW A, any loss of wetland acreage due to development or other means must be compensated in the form of mitigation wetlands. Mitigation wetlands are created wetlands built to replace both wetland acreage and function. The success of mitigation wetlands is varied, and there are questions as to our ability to replace lost wetland functions. In 2000 and 2001, I surveyed plants, amphibians and birds at nine created and nine natural wetlands and calculated a series of twelve response variables. I used the Wilcoxon paired sample test to look for differences among created and natural wetlands. I found no significant differences between created and natural wetlands for any of the response variables. Wetlands are important components of the landscape and their functions are influenced by their position within the landscape and the watershed. Many wetland animals require and depend on surrounding terrestrial land for foraging, migration, breeding, cover and hibernation. If we are to create wetlands that are ecologically similar to natural wetlands, then we must view and understand them from a larger, landscape perspective. Since I found no significant differences among created and natural wetlands, I combined the wetlands into a larger set of 18. GIS software was used to map each wetland and its surrounding land, and calculate a set of landscape-level predictor variables. I used simple linear regression and best subset multiple regression analyses to look for predictor variables that might account for the variation found in amphibian, bird and plant response variables. I found positive significant relationships between open water classification and plant, amphibian and bird species richness in both years. In addition, open water class was positively associated with bird and amphibian species diversity, and also the number of birds per census in both 2000 and 2001. The only negative significant association with open water class was with the proportion of T. latifolia. Watershed area was a significant positive predictor of amphibian in 2001, and of bird species richness, plant species richness, the number of birds per census and plant species diversity in both years. Wetland area was significant and positively related, in both years, to the number of birds per census and plant species richness. Invasive plant species richness was significant and positively associated with the length of the road in the watershed in both years, while invasive plant species cover was significant and positively associated with the percentage of urban, commercial and industrial land within 1 km of wetlands. Plant species richness and diversity were significant and positively associated with bird species richness and bird species diversity in both years, and with the number of birds per census in 2001. Open water class was part of four of the best subset models in 2000 and five models in 2001. Watershed area was part of seven best subset models in 2000 and five in 2001. The functions of wetlands are influenced by their position within a landscape. Therefore, the selection of an appropriate site for a mitigated wetland project should consider the surrounding landscape properties. The results of my study suggest that mitigated wetlands should be located 1) in large watersheds, 2) far from roads and urban areas, and near other wetlands. Also, mitigated wetlands should be constructed and maintained in a "hemimarsh" state so that the cover to water ratio is between 1:1 and 1:2, and the establishment and spreading of aggressive plant species such as T. latifolia should be controlled to help maintain a high level of structural diversity.
    • A Floristic Study of the Woodland Area of Brighton Town Park, Brighton, New York

      Bobear, Jean B.; McCormick, Jennifer Paula; The College at Brockport (1982-05-01)
      This study investigates the diversity of flora in the woodland area of Brighton Town Park, in a suburban area in Western New York. Data was collected through weekly field observation visits during the growing season (April – October) in 1981. The researcher also made monthly visits during the winter months (November 1981 – February 1982). She then resumed frequent visits on a daily to a weekly basis in March of 1982, continuing through May of that year. The researcher took extensive field notes which included information the sequence of blooming times of flowering plants, and observations of the frequency of occurrence and distribution of the species found in the park. The researcher took special note on the locations of rare/scarce plants and the distribution of all species with respect to the presence of the three major habitat types of the woodland (Beech-Maple [SAF 60], Swamp Forest [SAF 39], and an edge habitat at the woodland’s perimeter). Ten soil samples were also collected in October 1981 to provide data on soil pH. Additional field observations include seasonal changes in leaf litter and changes in the amount/pattern of light that reached the floor. Plants which grew only in light patches created by tree falls were noted as well. Results include floristic results, a list of dominant and associated tree species, a map of the locations of scarce trees, a list of toxic flora found in the woodland, and a species list of vascular plants. Appendices include soil pH measurements, soil types, and food values to wildlife.
    • A Fundamental Investigation into the Presence of Interstitial Cells of Cajal within the Gastrointestinal Tract of Dania rerio

      Leddon, Scott; The College at Brockport (2007-07-01)
      Coordinated gastrointestinal (GI) motility results from the complex interactions between interstitial cells of Cajal (ICC), enteric neurons, and smooth muscle cells. Kit positive immunoreactivity has been extensively utilized as a marker for ICC; these cells function to generate rhythmic depolarization in the GI smooth muscle termed the electrical slow wave. Coordinated GI motility is regulated by the electrical slow wave. Directly lesioning ICC populations with neutralizing antibodies results in GI dysmotility and loss of the electrical slow wave. Furthermore, GI dysmotility symptoms and other human pathologies have been correlated with ICC deficiencies within the GI tract. Currently, there are few treatments and therapeutic interventions for GI motility disorders, Irritable Bowl Syndrome alone affects up to 20% of the world population. 1- 5 The high prevalence of GI motility disorders combined with the lack of effective interventions, suggest new treatments are needed. Rational drug development and new treatment design will benefit from the development of new model systems. Greater understanding of the regulation of GI motility, pathologies that affect GI motility, and the development of new therapeutics will all benefit from a new model of GI motility. This thesis provides support to the use of Danio rerio, the zebrafish, as a model of human GI motility. Danio rerio is an excellent model system for several human physiological systems or diseases including macular degeneration, neural degenerative diseases, cardiovascular disease, cholesterol and lipid metabolism, and cardiovascular disease. 6 - 20 The zebrafish model system offers the opportunity for forward genetic analysis; novel genes, genetic elements, and pathologies can be characterized with reverse genetic screens through the evaluation of interesting phenotypes. Zebrafish reach sexual maturity quickly (three months), produce large numbers of offspring (100 per week), and are more cost efficient to house compared to mammalian models. Most seductive of zebrafish traits, optical transparency of larvae, enables direct visualization in-vivo of organ function (including the GI tract) under physiological settings, without perturbing the organism. This thesis critically examines the hypothesis that GI motility in the zebrafish involves ICC. Prior to the data presented within this thesis, there have not been any published reports on the presence of ICC within the zebrafish GI tract. Results from this investigation show Kit-like immunoreactivity within the muscular layers of the zebrafish GI tract. Additionally, orthologs for the human receptor tyrosine kinase Kit, kita and kitb, and orthologs for the human Kit ligand, kitla and kitlb, are shown to be expressed within the zebrafish GI tract. Kit receptor and ligand are necessary for ICC development and maintenance in mammals. Expression of kit receptors and ligands within the zebrafish GI tract are consistent with the hypothesis that ICC support spontaneous rhythmic contractions in the zebrafish-- this suggests that the zebrafish may be a suitable model for GI motility.
    • A New Functional Zebrafish Gastrointestinal Motility Assay

      Rich, Adam; Hess, Stacey; The College at Brockport (2007-08-01)
      Gastrointestinal (GI) motility is the coordinated contractions of smooth muscles resulting in mixing and propulsion of material through the GI tract. GI motility is influenced by smooth muscle, enteric neurons, and Interstitial cells of Cajal (ICC). New model systems for GI motility are needed because regulation of motility is poorly understood, and the number of drugs which can assist in GI motility disorders is insufficient. The Kit receptor is required for ICC development and maintenance in mammalian model systems and in humans. Mutations in the Kit receptor are associated with GI motility disorders. The objective of these experiments was to determine motility patterns in wildtype zebrafish and compare them to motility patterns in the zebrafish kita null mutant, sparse (spab5). Contraction frequency was measured from 7 minute digital video recordings of anesthetized larvae immobilized in 1.2% agar. Contraction frequency averaged 0.586 ± 0.222 contractions per minute in wildtype larvae at 7 dpf, and 0.329 ± 0.158 contractions per minute in 7 dpf sparse. The apparent contraction intensity was also scored, with a score from 0, no contractions, to 2, complete occlusion of the lumen. Contraction intensity averaged 1.250 ± 0.444 in wildtype larvae and 1.619 ± 0.498 in sparse larvae at 7 dpf. At 11 dpf contraction intensity decreased to 1.000 ± 0.000 and 1.125 ± 0.354, respectively. A functional motility assay was developed to quantify GI motility that contributes to propulsive movement of intestinal contents. Larvae were fed FITC labeled microspheres, washed, and fluorescence intensity of the GI tract was digitally imaged. Larvae were placed in clean system water, and reimaged after 24 hours. Fluorescence intensities were normalized against initial intensity of ingested microspheres at 7 dpf in the intestinal bulb of the anterior GI tract. At 7 dpf the change in fluorescence intensity in the anterior GI tract decreased by 0.371 ± 0.030 and 0.119 ± 0.021 in the posterior GI tract of wildtype larvae. At 11 dpf fluorescence intensity decreased to 0.455 ± 0.056 in the anterior GI tract, and 0.258 ± 0.046 in the posterior GI tract. Peritoneal injection of the ACK-2 anti-Kit antibody results in distention and an increased volume in the GI tract (Figure 12) (Maeda, Yamagata et al. 1992). These effects result from inactivation of Kit function by ACK-2. The size of the GI tract in sparse larvae appeared to be larger compared to wildtype, suggesting that the null kita mutant resulted in a phenotype similar to the ACK-2 effects on mice. We measured the area of a longitudinal cross section of wild type and sparse mutant larvae at 7 dpf. The average area of the GI tract in wildtype larvae was 4491 ± 754 and 5532 ± 880 in sparse larvae. Fluorescence spectroscopy was used to quantify the fluorescence intensity. Total fluorescence emission averaged 62,630 ± 23,780 counts per second immediately after ingestion in 11 dpf larvae. One day later, total fluorescence intensity averaged 53,277 ± 6,333 counts per second, a 15% decrease. 5-hydroxytryptamine (5-HT), a prokinetic agent, was used to validate the assay. One day after loading, the total fluorescence intensity decreased after application of 5-HT to 86,820 ± 21,850. 11 dpf zebrafish larvae ingest fluorescent labeled microspheres, and spectroscopic analysis showed reduced fluorescence intensity one day after loading. Functional studies showed a reduced contraction frequency and an increase in surface area between sparse mutant and wildtype larvae. The decrease in fluorescence intensity in wildtype larvae suggests aboral movement of microspheres, out of the posterior GI tract.
    • A Quantitative Study of Agglutination in Chlamydomonas Moewusii

      McLean, Robert J.; Sedita, Nancy Jane; The College at Brockport (1981-07-01)
      A quantitative method for the measurement of agglutination among Chlamydomonas moewusii gametes has been presented. Using this technique, it was demonstrated that gametes possess a higher Con A isoagglutinability than vegetative cells and the + mating type is more isoagglutinable by Con A in both the vegetative and gametic states than the - mating type. Pairing is inhibited by both colchicine and trypsin treatments of gametes but agglutination is not significantly inhibited. Data from preliminary experiments in which ferritin Con A was used as a marker was suggestive of the fact that colchicine may have prevented the distal clustering of Con A receptor sites on flagellar tips during mating interactions. The involvement of Con A receptor sites in mating interactions is implicated and the mechanism of tipping is discussed in terms of the colchicine and trypsin data presented.
    • A reexamination of stratification processes in Ides Cove, N.Y. with reference to sediment geochemistry

      Makarewicz, Joseph C.; Pesacreta, George Joseph; The College at Brockport (1981-06-01)
      Ides Cove is a small, relatively deep, isolated body of water off Irondequoit Bay of Lake Ontario, Irondequoit, N.Y. In 1970-71, the cove was meromictic with meromixis being attributed to the heavy application of deicing salts in the cove's watershed. Application of deicing salts to roads in the Town of Irondequoit has steadily declined from 31,230 metric tons in 1970-71 to 3,981 tons in 1979-80. Salt concentrations in surface waters of the cove have decreased since 1970. Complete mixing of the water column was observed during the winter of 1979-80 suggesting the town's "sensible salt use policy" has been a success. However, Cl- concentrations and conductivity in the hypolimnion have remained high due primarily to the saline discharge of ground water streams (mean annual Cl- = 303 mg/1). The discharge of saline ground water streams into the cove will affect mixing periods with autumnal and vernal turnover probably being replaced by a winter mixing period.
    • Activity of Phosphofructokinase in Summer Honey Bees (Apis mellifera) of Different Ages

      Kline, Larry K.; Greeno-Shannon, Jeffrey F.; The College at Brockport (1988-09-01)
      Phosphofructokinase activity may be an indicator in the aging process of honey bees (Apis mellifera). This paper seeks to quantify phosphofructokinase activity in summer honey bees of different ages. Honey bee flight muscle was utilized in tests for enzyme activity of phosphofructokinase at sequential stages of honey bee development. Homogenized honey bee flight muscle was ultracentrifuged and spectrophotometric measurements were made. This study found that the enzyme activity of phosphofructokinase of honey bees of different ages is low at day 0-1 and high from day 4-5 through 19-20 day old honey bees. This study lays a foundation for the study of summer and winter honey bees.
    • Age Related Changes in the Production and Metabolism of Testicular Steroids in the Rat

      Zummo, Joan E.; The College at Brockport (1985-09-01)
      Age-related changes in the production and metabolism of testicular steroids were studied by chronic in vivo hCG stimulation of 4 month (Y) and 18 month ( 0) rats, followed by in vitro hCG stimulation of the chronically stimulated testis tissue. The 0 showed a reduced initial response to hCG with significantly lower levels of T on D1 and D2. Although on D4-D10 the peripheral levels of T were not significantly different in Y and 0, at D1O the Y had returned to basal levels and the 0 were still at 3x basal. The D1O endogenous levels of T were also significantly higher in the 0. In vitro stimulation of the chronically stimulated testis tissue showed both Y and 0 unresponsive to further stimulation, but the 0 produced more T both with and without hCG stimulation. These facts may indicate some failure in the desensitization process in the 0. Another difference between Y and 0 was significantly higher levels of endogenous 20 ? hydroxyprogesterone in the o, suggesting possible differences in local control mechanisms. Neither chronic in vivo hCG stimulation nor in vitro aromatization of testosterone (T) to estradiol ( E2) resulted in any significant differences between Y and 0 in production or utilization of estradiol. However, during chronic hCG stimulation there were age-related differences in the ratios of T/E2 suggesting the possibility of an extra-testicular role for E2 in age-related changes. Aromatization of T resulted in lower levels of E1 and of ?4D in the 0 as compared to the Y. Also, when stimulated with hCG the Y, but not the 0, exhibited a significant decrease in production of ?4D. Other metabolites of T such as 7? hydroxytestosterone (7 ? OHT) and 7 ? hydroxyandrostendione (7 ? OH ? 4D) did not show age-related differences. Comparision of the clearance of T in acutely castrated 0 and Y rats showed that the 0 clear T more slowly than the Y. When injected with supraphysiological doses of T, both Y and 0 castratedrats cleared T faster than after acute castration. The 0 still showed slower t 1/2? and t 1/2? after these injections but the amount of T cleared from the blood calculated as MCR ( liters of blood cleared/ kg of body wt/ day) was not significantly different in the Y and 0.
    • Aging Changes in Testicular Responsivity to Gonadotropin Stimulation in Rats

      Chan, Stephen W.C.; McFarlin, Stephen Francis; The College at Brockport (1982-09-01)
      This study examined the effects of aging on testicular endocrine function and response to gonadotropin stimulation in male rats. Sprague-Dawley rats of 4 and 18 months were used throughout. Peripheral blood, testicular venous blood and endogenous testicular production were quantified for testosterone (T), 20 ? dihydroxyprogesterone (20?OH P), progesterone (P) and estradiol-17 ? (E_2). The levels of both P and E_2 were similar in both age groups but significantly less T and 20?OH P were found in testicular venous plasma and testis of aged rats. However, serum pH as quantified by RIA showed no age-related difference. In vitro incubations of both decapsulated testicular tissue and isolated Leydig cells with hCG (0-100 mIU) showed significantly less T production by the aged rats at basal levels and at all doses of hCG. Two groups of 4 and 18 month rats were injected i.v. with 50 IU hCG to study the in vivo response to gonadotropin stimulation. Peripheral blood was drawn at 0, 1 and 3 hours after hCG injection. Testicular venous (TV) blood and endogenous testicular production (EP) were determined 5 hours after hCG. T, P, E_2 and 20?OH P were quantified in all samples. Results indicate no age-related difference in P or E_2 production before or after hCG. T and 20?OH P levels were significantly lower in TV blood and EP 3 Hr after injection. Peripheral blood concentrations of T showed significantly higher levels in 4M rats at 0 and 1 hours, however, at 3 hours post-hCG, peripheral serum T levels were found to be similar in both age groups. This similarity in peripheral T levels did not reflect secretory differences as demonstrated by TV and EP of T 3 hours after hCG, but was more likely due to differences in the metabolic clearance rates (MCR) of T. We therefore conclude that reproductive aging in rats is in part due to an inherent defect in testicular function. This defect may be a lesion in the steroidogenic enzymes leading to the formation of T which lies distal to LH binding, cAMP production and P formation. Testicular E_2 may not play a major role in reproductive senescence in rats.
    • Amino Acids in Asclepias Nectar

      Hammond, H. David; Sadwick, Steven Edward; The College at Brockport (1983-12-01)
      Thin Layer Chromatography in a three solvent system was used to determine the amino acid components in the nectar of three milkweed species. The amino acid complements differed in each species, indicating possible use as a chemosystematic character. The differences in the types of nectarivores or pollinators that visited each species. However, where floral color variations were observed in two of the species, no variation was seen in their respective amino acid complements.
    • An Analysis of Factors Potentially Limiting the Abundance of the Zebra Mussel (Dreissena polymorpha) in Salmon Creek, Monroe County, New York

      Haynes, James M.; Miller, Steven J.; The College at Brockport (1994-10-01)
      First reported in the Great Lakes basin in 1988, the zebra mussel (Dreissena polymorpha) has spread throughout the Great Lakes and central U.S. With a direct connection to Lake Erie, the New York State Erie Barge Canal was colonized by zebra mussels as early as the spring of 1989. Salmon Creek flows northeast from southern Monroe County to Braddock Bay, and Erie Barge Canal water is used to supplement creek flows north of the canal. At the beginning of the canal outfall channel to the creek is a dense bed of zebra mussels which has existed since at least 1990. After the outfall channel merges with the creek, within 75 meters downstream adult densities drop to less than one mussel per square meter. In the summer of 1993 veliger counts in the canal were on average 52 times greater than they were in Salmon Creek. Water quality in the creek and the canal were similar. pH ranged from 7.5 to 8.2 in Salmon Creek and from 7.3 to 8.3 in the canal, both well within the established range of zebra mussels. Temperature in Salmon Creek did not exceed 30°C, the maximum tolerated by zebra mussels, and calcium concentrations did not fall below 40ppm, the minimum tolerated by zebra mussels. Particulate organic carbon in the creek (21. 6 ± 1.8 ppm) did not differ from that in the canal (21.5 ± 2.3 ppm). Current in the creek (0.03 - 0.16 m/sec) did not exceed ranges that impair zebra mussel settling and growth. Given these appropriate physical habitat and water quality conditions and an abundant source of veligers, the factors limiting zebra mussel colonization in Salmon Creek appear to be 1) detention of zebra mussels by the wetland through which the canal discharge flows, 2) filtering of phytoplankton and veligers by the dense bed of adult zebra mussel at the beginning of the canal outfall channel, or 3) inappropriate food quality in the creek.
    • An Experimental Test of the Crayfish (Orconectes immunis) as a Control Mechanism for Submerged Aquatic Macrophytes

      Makarewicz, Joseph C.; Letson, Michael Allen; The College at Brockport (1991-05-01)
      The ability of the crayfish Orconectes immunis to graze submerged aquatic macrophytes was evaluated experimentally. Crayfish at densities greater than 140-150 g/m2 significantly decreased macrophyte biomass in all experiments. The rate of crayfish grazing in cages where significant decreases in macrophyte biomass occurred averaged 0.012 g of macrophytes consumed/crayfish/m2/day.
    • Analysis of the Flagellar Membrane Proteins of Chlamydomonas moewusii

      McLean, Robert J.; Jamieson, Cheryl Lynn; The College at Brockport (1978-01-01)
      This investigation was concerned with the analysis of the proteins isolated from the gamone (flagellar membrane vesicles isolated from the medium) of Chlamydomonas moewusii. SDS-polyacrylamide gel electrophoresis of gamone isolated from (+) and (-) cell types indicated possible differences between vegetative and gametic gamone within mating types and a degree of similarity within vegetative and gametic gamone of both mating types. Electrophoretic analysis of several molecular weight standards indicated that the major proteins from all gamone types are glycoproteins of relatively high molecular weight (100-150, 000 D.) Con A affinity chromatography of membranes solubilized in 1% DOC in 10 mM Tris, pH 8.2, showed that 4.2% of the proteins isolated from the (-) gamone and 7.35%-16.4% of the proteins isolated from the (+) gamone bound to Con A. These proteins could subsequently be eluted with 2% ?-methylmannoside. Attempts to recover the proteins from the Con A affinity chromatography column were unsuccessful.
    • Anionic Transport in Nitella clavata

      Barr, Charles E.; Bower, Bonnie L.; The College at Brockport (1978-07-01)
      This study examines aspects of anion transport, focusing on Cl-, No_3- and So_4-2 in Nitella clavata. The researcher measures the uptake of radioactive Cl- in the presence/absence of a hexose in order to determine if glucose inhibits Cl- influx. The author grew Nitella clavata in open tanks of culture solution, with a light intensity of 100 foot-candles at the cultures’ surface. Only the first, second, or third intermodal cells proximal to the apical tip were used. Harvested cells were then conditioned from one to seven days under controlled conditions. First, the researcher used titration to measure net hydrogen ion influxes and hydroxide effluxes. Then the researcher treated cells in with K/experimental solutions and rinsed them in non-tracer/appropriate experimental solution in order to measure cell radioactivity. The researcher also measured unidirectional chloride efflux using a radioassay with a Nuclear-Chicago low background gas flow counter. Intracellular chloride activity was determined by measuring vacuolar sap chloride concentration potentiometrically. Ultimately, the researcher could find no evidence to support the hypothesis that Nitella clavata possesses a hexose/H+ cotransport system, nor could she provide evidence for a Cl-/H+ cotransport system through competitive inhibition with a hexose/H+ mechanism. Possibilities for further research include radioisotope tracing of NO_3-, Cl- and SO_4-2 in the presence of other anions.
    • Blue-Green Algal Mats from Acidified Adirondack Lakes: Mat Structure and pH Response of Algal Isolates

      Makarewicz, Joseph C.; Leupold, Maureen Ann; The College at Brockport (1983-10-01)
      Seven acidified lakes in the Adirondack mountains of New York, USA were sampled for benthic algae during the summer of 1982. Benthic cyanophyte mats, dominated by Schizothrix spp. were found in three of the seven lakes sampled (Big Moose, pH 4.00-4.40; Limekiln, pH 4.60-5.30; Wolf, pH 3.45-3.70). The blue-green algal mats found were structurally similar to living stromatolite analogs found in other extreme environments. Under controlled laboratory conditions, unialgal isolates of Schizothrix calcicola (Ag.) Gom., grew best at or near neutrality but could survive and grow slowly at low pH (4.0, 5.0). Increased nutrient levels appeared to have little effect on growth or survival in buffered low pH (4.0) media. Cultures of S.calcicola were able to raise the pH of unbuffered media three pH units in less than 72 hours. Clumping and aggregation of filaments was enhanced by lowering the pH (to pH 3.5 in 5.5 hours) of actively growing cultures.
    • Cardiac Na+, K+, Mg+2 and Ca+2 Concentrations in Chronically Exercised Rats

      Smith, Delmont C.; Tresham, Harriet Spaulding; The College at Brockport (1981-03-01)
      Bradycardia as a result of chronic exercise was induced in a group of male Sprague-Dawley rats. These experimental animals ran two hours daily, 6 days a week for 6 weeks, at a speed of 12.9 meters per minute, in a motorized running cage. Previous studies have indicated that this regimen adequately resulted in exercise bradycardia without corresponding hypertrophy. Hearts from this experimental group of chronically exercised rats were assayed via atomic absorption spectrophotometry for total tissue content of Na+ , K+ , Mg +2, and Ca +2 . These results were compared with the concentrations obtained from hearts of a group of sedentary control rats. Differences were found in the concentrations of the ions between the two groups, but these differences were all non-significant according to the Student t-test. The following concentration ratios were calculated for both groups: Na+ : K+, Mg+2: Ca+2, and Ca+2 : Na+. No significant differences were found. There was considerable variation among individual results; an increased sample size might minimize the effects of this variation on the statistical tests, perhaps indicating significant differences in the ionic concentrations, particularly with regard to calcium concentration.
    • Cardiac Na+, K+, Mg+2 and Ca+2 Concentrations in Chronically Exercised Rats

      Smith, Delmont C.; Tresham, Harriet Spaulding; The College at Brockport (1981-03-01)
      Bradycardia as a result of chronic exercise was induced in a group of male Sprague-Dawley rats. These experimental animals ran two hours daily, 6 days a week for 6 weeks, at a speed of 12.9 meters per minute, in a motorized running cage. Previous studies have indicated that this regimen adequately resulted in exercise bradycardia without corresponding hypertrophy. Hearts from this experimental group of chronically exercised rats were assayed via atomic absorption spectrophotometry for total tissue content of Na+, K+, Mg+2, Ca+2. These results were compared with the concentrations obtained from hearts of a group of sedentary control rats. Differences were found in the concentrations of the ions between the two groups, but these differences were all non-significant according to the Student t-test. The following concentration ratios were calculated for both groups: Na+: K+, Mg+2: Ca+2, and Ca+2 : Na+. No significant differences were found. There was considerable variation among individual results; an increased sample size might minimize the effects of this variation on the statistical tests, perhaps indicating significant differences in the ionic concentrations, particularly with regard to calcium concentration.
    • Chironomid (Diptera: Chironomidae) Larvae as Indicators of Water Quality in Irondequoit Creek, NY

      Haynes, James M.; Cook, George E.; The College at Brockport (1998-12-01)
      Chironomid community structure and mouthpart deformities were examined as indicators of pollution or degradation of water quality in the Irondequoit Creek watershed. Differences in Simpson's diversity, taxa richness, and chironomid abundance were assessed in upper, middle, and lower creek locations to determine changes as the creek passes through increasingly populated areas. Differences in the same measures also were assessed in vegetation, mud, and gravel habitats in order to assure that any changes observed were not due to differences in chironomid community structure in dissimilar substrates. Diversity and taxa richness were highest in the upper creek and lowest in the lower creek. Abundance was highest in the middle creek. All three measures were highest in the gravel habitats and lowest in the vegetation habitats. Slight organic pollution impacts on the creek were indicated by lower diversity and richness values in the lower locations of lrondequoit Creek and by community structure differences. Mouthpart deformity comparisons were inconclusive because affected taxa were not present at all sites. This study brings into question the feasibility of using chironomid communities and deformity rates as indicators of water quality changes in the Irondequoit Creek system. Due to the high variance in chironomid distributions, a larger number of samples is needed to detect changes in chironomid communities. Other changes in sampling methods may also be necessary.
    • Chlamydomonas moewusii Pairing: Optimal Conditions and Drug Effects

      McLean, Robert J.; Lembo, Thomas Michael; The College at Brockport (1978-01-01)
      The effect of various mating conditions on the pairing percentages in Chlamydomonas moewusii were determined. A pairing percentage of 43% was obtained when gametes induced at 21°c were shifted to a mating temperature of 19°c for 1 hour. The lowest pairing percentage was obtained when cells were induced at 30°c and shifted to 19°c for 1 hour. The anti-microtubule agent colchicine and the anti-microfilament agent cytochalasin B were employed to determine their effect on pairing in C. moewusii. Both drugs demonstrated an inhibitory effect on pairing in Chlamydomonas. The inhibition of gametic pairing in cells treated with colchicine was greater than those gametes treated with cytochalasin B. Low temperature is known to disrupt microtubules. Gametes exposed to 4°c exhibited a dramatic decrease in pairing percentages. These results seem to suggest an interacting relationship between microtubules and microfilaments that play a crucial role in the pairing of Chlamydomonas moewusii gametes.