623 research outputs found

    Effects of an Ammonia-Rich Municipal Sewage Effluent on Iowa River Fauna Near Marshalltown, Iowa

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    The effect of the Marshalltown municipal sewage effluent on Iowa River water quality and fauna was evaluated from July 1976 through August 1977. The effluent contains high total ammonia and un-ionized ammonia concentrations due to ammonia-rich discharges from meat packinghouses. Dissolved oxygen, pH, temperature, total ammonia nitrogen, and un-ionized ammonia data were collected at.12 sampling stations extending 18 km downstream from the sewage effluent discharge. Wild fish collections were made by using electrofishing, seines, and hoopnets. Thirty-eight fish species were collected during the study. Channel catfish. (Ictalurus punctatus) and smallmouth bass (Micropterus dolomieus) were the most common gamefish. No consistent depression in wild fish diversity was seen below the sewage discharge point. Eight hundred thirty caged channel catfish were used in conducting 13 4-day field toxicityty tests at 5 different river stations. Only 2% mortality was observed. Macroinvertebrate diversity and density were determined by using artificial substrate samplers placed at 5 river stations during 2 3-week exposure periods in the summer of 1976. Macroinvertebrate diversity recovered 770-1550 m downstream from the sewage discharge point. The applicability of the EPA un-ionized ammonia criterion and the Iowa total ammonia nitrogen standard is evaluated in light of the findings from this study

    Fish Distribution in the Skunk River below Ames, Iowa

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    The Skunk River has been straightened most of the way from Ames to Colfax. In the summer of 1968, 24 species of fish were collected. There were few species other than minnows, and red shiner (Notropis lutrensis), bigmouth shiner (N. dorsalis) and sand shiner (N. straminous) were most abundant. Water levels were above normal during the study and effects of pollution upon fish distribution were not pronounced. The diversity index, d, at the station where treated-sewage wastes entered, was lower than at stations up and down stream but was higher than at the four stations farthest downstream. Uniformity of habitat resulting from stream-straightening probably limits species diversity

    The Limitations of Retirement Plan Law

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    Comparative Genome-Wide Screening Identifies a Conserved Doxorubicin Repair Network That Is Diploid Specific in Saccharomyces cerevisiae

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    The chemotherapeutic doxorubicin (DOX) induces DNA double-strand break (DSB) damage. In order to identify conserved genes that mediate DOX resistance, we screened the Saccharomyces cerevisiae diploid deletion collection and identified 376 deletion strains in which exposure to DOX was lethal or severely reduced growth fitness. This diploid screen identified 5-fold more DOX resistance genes than a comparable screen using the isogenic haploid derivative. Since DSB damage is repaired primarily by homologous recombination in yeast, and haploid cells lack an available DNA homolog in G1 and early S phase, this suggests that our diploid screen may have detected the loss of repair functions in G1 or early S phase prior to complete DNA replication. To test this, we compared the relative DOX sensitivity of 30 diploid deletion mutants identified under our screening conditions to their isogenic haploid counterpart, most of which (nβ€Š=β€Š26) were not detected in the haploid screen. For six mutants (bem1Ξ”, ctf4Ξ”, ctk1Ξ”, hfi1Ξ”,nup133Ξ”, tho2Ξ”) DOX-induced lethality was absent or greatly reduced in the haploid as compared to the isogenic diploid derivative. Moreover, unlike WT, all six diploid mutants displayed severe G1/S phase cell cycle progression defects when exposed to DOX and some were significantly enhanced (ctk1Ξ” and hfi1Ξ”) or deficient (tho2Ξ”) for recombination. Using these and other β€œTHO2-like” hypo-recombinogenic, diploid-specific DOX sensitive mutants (mft1Ξ”, thp1Ξ”, thp2Ξ”) we utilized known genetic/proteomic interactions to construct an interactive functional genomic network which predicted additional DOX resistance genes not detected in the primary screen. Most (76%) of the DOX resistance genes detected in this diploid yeast screen are evolutionarily conserved suggesting the human orthologs are candidates for mediating DOX resistance by impacting on checkpoint and recombination functions in G1 and/or early S phases

    Structure-based prediction of insertion-site preferences of transposons into chromosomes

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    Mobile genetic elements with the ability to integrate genetic information into chromosomes can cause disease over short periods of time and shape genomes over eons. These elements can be used for functional genomics, gene transfer and human gene therapy. However, their integration-site preferences, which are critically important for these uses, are poorly understood. We analyzed the insertion sites of several transposons and retroviruses to detect patterns of integration that might be useful for prediction of preferred integration sites. Initially we found that a mathematical description of DNA-deformability, called V(step), could be used to distinguish preferential integration sites for Sleeping Beauty (SB) transposons into a particular 100 bp region of a plasmid [G. Liu, A. M. Geurts, K. Yae, A. R. Srinivassan, S. C. Fahrenkrug, D. A. Largaespada,J. Takeda, K. Horie, W. K. Olson and P. B. Hackett (2005) J. Mol. Biol., 346, 161–173 ]. Based on these findings, we extended our examination of integration of SB transposons into whole plasmids and chromosomal DNA. To accommodate sequences up to 3 Mb for these analyses, we developed an automated method, ProTIS(Β©), that can generate profiles of predicted integration events. However, a similar approach did not reveal any structural pattern of DNA that could be used to predict favored integration sites for other transposons as well as retroviruses and lentiviruses due to a limitation of available data sets. Nonetheless, ProTIS(Β©) has the utility for predicting likely SB transposon integration sites in investigator-selected regions of genomes and our general strategy may be useful for other mobile elements once a sufficiently high density of sites in a single region are obtained. ProTIS analysis can be useful for functional genomic, gene transfer and human gene therapy applications using the SB system

    Similar hibernation physiology in bats across broad geographic ranges

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    This is a post-peer-review, pre-copyedit version of an article published in Journal of Comparative Physiology B. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00360-021-01400-xSpecies with broad geographic ranges may experience varied environmental conditions throughout their range leading to local adaptation. Variation among populations reflects potential adaptability or plasticity, with implications for populations impacted by disease, climate change, and other anthropogenic influences. However, behavior may counteract divergent selection among populations. We studied intraspecific variation in hibernation physiology of Myotis lucifugus (little brown myotis) and Corynorhinus townsendii (Townsend's big-eared bat), two species of bats with large geographic ranges. We studied M. lucifugus at three hibernacula which spanned a latitudinal gradient of 1500 km, and C. townsendii from 6 hibernacula spread across 1200 km latitude and 1200 km longitude. We found no difference in torpid metabolic rate among populations of either species, nor was there a difference in the effect of ambient temperature among sites. Evaporative water loss was similar among populations of both species, with the exception of one C. townsendii pairwise site difference and one M. lucifugus site that differed from the others. We suggest the general lack of geographic variation is a consequence of behavioral microhabitat selection. As volant animals, bats can travel relatively long distances in search of preferred microclimates for hibernation. Despite dramatic macroclimate differences among populations, hibernating bats are able to find preferred microclimate conditions within their range, resulting in similar selection pressures among populations spread across wide geographic ranges.Department of Defense Strategic Environmental Research and Development Program || United States Fish and Wildlife Service, Grant F17AP00593 || Texas Tech University || Alberta Conservation Association

    Investigating the effect of independent blinded digital image assessment on the STOP GAP trial

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    Background Blinding is the process of keeping treatment assignment hidden and is used to minimise the possibility of bias. Trials at high risk of bias have been shown to report larger treatment effects than low risk studies. In dermatology, one popular method of blinding is to have independent outcome assessors who are unaware of treatment allocation assessing the end point using digital photographs. However, this can be complex, expensive and time-consuming. The objective of this study was to compare the effect of blinded and unblinded outcome assessment on the results of the STOP GAP trial. Methods The STOP GAP trial compared prednisolone to ciclosporin in treating pyoderma gangrenosum. Participants’ lesions were measured at baseline and 6 weeks to calculate the primary outcome, speed of healing. Independent blinded assessors obtained measurements from digital photographs using specialist software. In addition, unblinded treating clinicians estimated lesion area by measuring length and width. The primary outcome was determined using blinded measurements where available, otherwise unblinded measurements were used (method referred to as trial measurements). In this study, agreement between the trial and unblinded measurements was determined using the intraclass correlation coefficient (ICC). The STOP GAP primary analysis was repeated using unblinded measurements only. We introduced differential and non-differential error in unblinded measurements and investigated the effect on the STOP GAP primary analysis. Results 86 (80%) of the 108 patients were assessed using digital images. Agreement between trial and unblinded measurements was excellent (ICC=0.92 at baseline; 0.83 at 6 weeks). There was no evidence that the results of the trial primary analysis differed according to how the primary outcome was assessed (p-value for homogeneity = 1.00). Conclusions Blinded digital image assessment in STOP GAP did not meaningfully alter trial conclusions compared with unblinded assessment. However, as the process brought added accuracy and credibility to the trial it was considered worthwhile. These findings question the usefulness of digital image assessment in a trial with an objective outcome and where bias is not expected to be excessive. Further research should investigate if there are alternative, less complex ways of incorporating blinding in clinical trials
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