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Use of the index of biotic integrity to assess physical habitat degradation in warmwater streams (1995)

Shields, F. D. ; Knight, S. S. ; Cooper, C. M.

Springer

Hydrobiologia 312 (1995), S. 191-208

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ISSN: 1573-5117

Keywords: index of biotic integrity ; stream ; fish ; erosion ; sediment ; physical habitat

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Indices of biotic integrity (1131) were computed for two annual fish collections from 27 locations along the bluffline bordering the Mississippi River alluvial plain in northwestern Mississippi. Study sites exhibited varying degrees of physical habitat degradation due to accelerated channel erosion. Objectives of index application were to quantify existing environmental quality and to test the IBI as a tool for relating fish population characteristics to physical degradation. Physical habitat data were collected concurrently with fish at all sites, and physical habitat descriptors were compared with the IBI scores and component metrics. Three to 23 fish species were captured from each site, and species richness explained 64–70% of the variance in IBI scores. Fish collections were dominated by insectivores tolerant of habitat and water quality degradation. Suckers and piscivores were relatively uncommon. The IBI scores were generally not reflective of physical habitat conditions. Variation in IBI scores was indicative of only the grossest differences in physical habitat quality. Weak relationships between physical habitat quality and IBI scores may have been due to large temporal variations in biotic integrity typical of degraded habitats. Alternatively, water quality degradation, which we did not measure, may have confounded relationships between physical habitat and fish metrics. Regional application of the IBI as a habitat assessment tool in landscapes with widespread physical degradation must overcome lack of suitable reference sites, large temporal variation in IBI scores, and small numbers of fish per collection, leading to lower confidence levels for IBI scores. The scarcity of lightly impacted sites may hinder detection of biotic integrity response along gradients of physical habitat quality.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00015512

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Cytokine induction of proliferation and expression of CDC2 and cyclin a in FDC-P1 myeloid hematopoietic progenitor cells: Regulation of ubiquitous and cell cycle-dependent histone gene transcription factors (1995)

Shakoori, A. R. ; van Wijnen, A. J. ; Cooper, C. ; [et al.]

New York, N.Y. : Wiley-Blackwell

Journal of Cellular Biochemistry 59 (1995), S. 291-302

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ISSN: 0730-2312

Keywords: IL-3-dependent FDC-P1 cells ; histone H4 gene ; cell cycle control ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: To evaluate transcriptional mechanisms during cytokine induction of myeloid progenitor cell proliferation, we examined the expression and activity of transcription factors that control cell cycle-dependent histone genes in interleukin-3 (IL-3)-dependent FDC-P1 cells. Histone genes are transcriptionally upregulated in response to a series of cellular regulatory signals that mediate competency for cell cycle progression at the G1/S-phase transition. We therefore focused on factors that are functionally related to activity of the principal cell cycle progression at the G1/S-phase transition. We therefore focused on factors that are functionally related to activity of the principal cell cycle regulatory element of the histone H4 promoter:CDC2, cyclin A, as well as RB-and IRF-related proteins. Comparisons were made with activities of ubiquitous transcription factors that influence a broad spectrum of promoters independent of proliferation or expression of tissue-specific phenotypic properties. Northern blot analysis indicates that cellular levels of cyclin A and CDC2 mRNAs increase when DNA synthesis and H4 gene expression are initiated, supporting invoulvement in cell cycle progression. Using gel-shift assays, incorporating factor-specific antibody and oligonucleotide competition controls, we define three sequential periods following cytokine stimulation of FDC-P1 cells when selective upregulation of a subset of transcription factors is observed. In the initial period, the levels of SP1 and HiNF-P are moderately elevated; ATF, AP-1, and HiNF-M/IRF-2 are maximal during the second period; while E2F and HiNF-D, which contain cyclin A as a component, predominate during the third period, coinciding with maximal H4 gene expression and DNA synthesis. Differential regulation of H4 gene transcription factors following growth stimulation is consistent with a principal role of histone gene promoter elements in integrating cues from multiple signaling pathways that control cell cycle induction and progression. Regulation of transcription factors controlling histone gene promoter activity within the context of a staged cascade of responsiveness to cyclins and other physiological mediators of proliferation in FDC-P1 cells provides a paradigm for experimentally addressing interdependent cell cycle and cell growth parameters that are operative in hematopoietic stem cells. © 1995 Wiley-Liss, Inc.

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