Response of bacteria and phytoplankton to contaminated sediments from Trenton Channel, Detroit River

Several types of bioassays were used in 1986 and 1987 to investigate the effect of contaminated sediments on natural populations of bacteria and phytoplankton from the Trenton Channel, Detroit River. The approach included the measurement of uptake of 3 H-glucose or 3 H-adenine by bacteria and 14 C-bicarbonate by phytoplankton in the presence of different amounts of Trenton Channel and Lake Michigan (control) sediments. Trenton Channel sediments are contaminated by high levels of toxic organic compounds and metals, especially zinc, lead, and copper. Because levels of biomass of bacteria and phytoplankton varied widely among the different bioassays, it was necessary to adjust uptake rates for biomass. Biomass adjustments were made using acridine orange counts for bacteria and chlorophyll measurements for phytoplankton. The results show a statistically significant suppression of uptake of substrates for both bacteria and phytoplankton with increasing amounts of sediment. Uptake was suppressed as much as 90 percent for bacteria and 93 percent for phytoplankton at 1200 mg l -1 of Trenton Channel sediments compared to bioassays without sediment. Uncontaminated Lake Michigan sediment suppressed uptake much less than Detroit River sediment; the difference in suppression of uptake between the two types of sediment was statistically significant for both bacteria and phytoplankton.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42882/1/10750_2004_Article_BF00024761.pd

Distribution and Abundance of Larval Burbot and Deepwater Sculpin in Lake Michigan

Samples from seven locations at depths to 21 m, collected over periods of up to 8 years, were used to describe the nearshore distribution and abundance of burbot Lota lota and deepwater sculpin Myoxocephalus thompsoni larvae in Lake Michigan. Based upon power‐plant‐entrainment samples and field collections, burbot larvae (3.0–7.5 mm) occurred from late March to mid‐June, most abundantly in April and May, and most often at water temperatures of 6–12 C. Larvae were collected from the 0.5‐ to 13.5‐m depth strata as far lakeward as the 21‐m bottom contour, the limit of offshore sampling. In eastern Lake Michigan, highest densities (up to 843 larvae/1,000 m3) were at the 1‐m contour; in Green Bay, up to 24,000 larvae/1,000 m3 were detected near the Bark River. High densities of burbot larvae at bottom depths 3 m and less indicated inshore spawning and river spawning at some sites. Deepwater sculpin larvae first occurred in early February and were common in March and April entrainment samples. Larvae (8.0–22.0 mm) were in nearshore waters usually through May at depth strata of 0.5 to 17 m as far lakeward as the 18‐m bottom contour. Most larvae occurred at water temperatures below 6 C. Field densities were low, 5 to 78 larvae/1,000 m3. Deepwater sculpin larvae were pelagic and were dispersed over great distances by currents.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141932/1/tafs0162.pd

Interleukin-18 induces angiogenic factors in rheumatoid arthritis synovial tissue fibroblasts via distinct signaling pathways

Objective Interleukin-18 (IL-18) is a proinflammatory cytokine implicated in the pathogenesis of rheumatoid arthritis (RA). This study was undertaken to examine the role of IL-18 in up-regulating secretion of the angiogenic factors stromal cell–derived factor 1Α (SDF-1Α)/CXCL12, monocyte chemoattractant protein 1 (MCP-1)/CCL2, and vascular endothelial growth factor (VEGF) in RA synovial tissue (ST) fibroblasts, and the underlying signaling mechanisms involved. Methods We used enzyme-linked immunosorbent assays, Western blotting, and chemical inhibitors/antisense oligodeoxynucleotides to signaling intermediates to assess the role of IL-18. Results IL-18 significantly enhanced the production of SDF-1Α/CXCL12, MCP-1/CCL2, and VEGF in RA ST fibroblasts, in a time- and concentration-dependent manner. IL-18–induced SDF-1Α/CXCL12 up-regulation was dependent on JNK, p38 MAPK, phosphatidylinositol 3-kinase (PI3K), and NFΚB. While IL-18–induced production of SDF-1Α/CXCL12 was also dependent on protein kinase CΔ (PKCΔ), production of MCP-1/CCL2 was dependent on PKCΑ, not PKCΔ. Additionally, RA ST fibroblast IL-18–induced MCP-1/CCL2 production was mediated by JNK, PI3K, and NFΚB. In contrast, IL-18 did not induce secretion of RA ST fibroblast MCP-1/CCL2 or VEGF via p38 MAPK. IL-18–induced RA ST fibroblast production of VEGF was mediated mainly by JNK-2, PKCΑ, and NFΚB. IL-18 induced phosphorylation of JNK, PKCΔ, p38 MAPK, and activating transcription factor 2 (ATF-2) in RA ST fibroblasts in a time-dependent manner, with JNK-2 being upstream of PKCΔ, ATF-2, and NFΚB. Conclusion These data support the notion that IL-18 has a unique role in inducing the secretion of angiogenic SDF-1Α/CXCL12, MCP-1/CCL2, and VEGF in RA ST fibroblasts, via distinct signaling intermediates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56041/1/22705_ftp.pd

PCR-TTGE Analysis of 16S rRNA from Rainbow Trout (Oncorhynchus mykiss) Gut Microbiota Reveals Host-Specific Communities of Active Bacteria

This study assessed the relative contributions of host genetics and diet in shaping the gut microbiota of rainbow trout. Full sibling fish from four unrelated families, each consisting of individuals derived from the mating of one male and one female belonging to a breeding program, were fed diets containing either vegetable proteins or vegetable oils for two months in comparison to a control diet consisting of only fish protein and fish oil. Two parallel approaches were applied on the same samples: transcriptionally active bacterial populations were examined based on RNA analysis and were compared with bacterial populations obtained from DNA analysis. Comparison of temporal temperature gradient gel electrophoresis (TTGE) profiles from DNA and RNA showed important differences, indicating that active bacterial populations were better described by RNA analysis. Results showed that some bacterial groups were significantly (P<0.05) associated with specific families, indicating that microbiota composition may be influenced by the host. In addition, the effect of diet on microbiota composition was dependent on the trout family

Localization of type 1 diabetes susceptibility to the MHC class I genes HLA-B and HLA-A

The major histocompatibility complex (MHC) on chromosome 6 is associated with susceptibility to more common diseases than any other region of the human genome, including almost all disorders classified as autoimmune. In type 1 diabetes the major genetic susceptibility determinants have been mapped to the MHC class II genes HLA-DQB1 and HLA-DRB1 (refs 1-3), but these genes cannot completely explain the association between type 1 diabetes and the MHC region. Owing to the region's extreme gene density, the multiplicity of disease-associated alleles, strong associations between alleles, limited genotyping capability, and inadequate statistical approaches and sample sizes, which, and how many, loci within the MHC determine susceptibility remains unclear. Here, in several large type 1 diabetes data sets, we analyse a combined total of 1,729 polymorphisms, and apply statistical methods - recursive partitioning and regression - to pinpoint disease susceptibility to the MHC class I genes HLA-B and HLA-A (risk ratios >1.5; Pcombined = 2.01 × 10-19 and 2.35 × 10-13, respectively) in addition to the established associations of the MHC class II genes. Other loci with smaller and/or rarer effects might also be involved, but to find these, future searches must take into account both the HLA class II and class I genes and use even larger samples. Taken together with previous studies, we conclude that MHC-class-I-mediated events, principally involving HLA-B*39, contribute to the aetiology of type 1 diabetes. ©2007 Nature Publishing Group