Assignment of the HOX2 and HOX3 gene clusters to the bovine chromosome regions 19q17-qter and 5q14-23

The homeobox 2 (HOX2) and homeobox 3 (HOX3) clusters have been chromosomally assigned in cattle by in situ hybridization. The probes employed were a murine probe for the mapping of HOX2 to 19q17-qter and human probes for the mapping of HOX3 to 5q14-q23. These assignments confirm the chromosomal assignment of two syntenic groups, consisting of loci located on human chromosome 12 (bovine chromosome 5) and the long arm of human chromosome 17 (bovine chromosome 19).     

Growth of macrophytes and ecosystem consequences in a lowland Danish stream

SUMMARY. 1. The River Suså is a small, nutrient-rich stream situated in an open landscape with clayish subsoil under intensive cultivation. Discharge was variable daily and seasonally due to low groundwater input. Above-ground development of submerged macrophytes was restricted to late May to November, when water velocity and depth were low. Dominant macrophytes were rooted Potamogeton pectinatus and Sparganium emersum and unrooted Cladophora . Biomass development was closet) related to light availability.
2. Growth rates of macrophytes were linearly related to light availability when self-shading was accounted for. Potamogeton pectinatus grew rapidly m May-June, concentrated the biomass at the water-surface during July-August, and then declined exponentially when the shoots became basally senescent. Sparganium emersum had linear, flexible leaves that were continuously replaced from a basal meristem. Sparganium emersum was less susceptible to high water velocities than Potamogeton pectinatus and the biomass declined later and at lower rates during autumn. Sparganium emersum also regrew after culling that left its meristem intact in the sediment. Unrooted Cladophora developed a high biomass during sunny periods and subsequently disappeared at high discharges. The summer biomass of rooted macrophytes was greater in years with high summer discharge, whereas the biomass of Cladophora and of the epiphytic microbial community was lower due to scouring.
3. Submerged macrophytes played a key role in structure and functioning of the ecosystem. They reduced water velocities two to four fold during summer and promoted extensive organic sedimentation. The biomass of benthic diatoms declined parallel to increased macrophyte shading and sedimentation. In addition, submerged macrophytes formed a large substratum for macroinvertebrates and for a microbial community.     

Effects of Environmental Stressors and Immunosuppressants on Immunity in Fundulus heteroclitus

Environmental stressors have been shown to alter immunocompetencein mammals. Similar effects have been reported in fish. Thepurpose of this paper is to review the literature concerningthe white blood cells and immunity in Fundulus heteroclitus.Evidence for immunosuppression following prolonged captivity,handling, hypophysectomy, radiation, changes in temperatureand salinity, and exposure to chemicals including environmentalpollutants is discussed. New evidence for immunosuppressionfollowing exposure to benzo-a-pyrene, pentachlorophenol, andhexachlorobenzene is presented. Possible mechanisms of immunealteration and the consequences to F. heteroclitus are discussed.     

The bovine gene map

Summary. The present status of the bovine gene map as well as some of the methods and strategies important for future efforts in completing the gene map of cattle are reviewed.     

Induction of Salt Sensitivity in Ophiostoma and Its Reversal by Imidazole Derivatives

Cells of the ascomycete Ophiostoma multiannulatum became sensitive to inorganic salts after a heat shock or a treatment with 2,4-dinitrophenol. The induced sensitivity to chloride and bromide ions could be largely reversed by histidine and certain other imidazole derivatives. No other organic compounds tested except imidazoles possessed this ability. The sensitization is interpreted as a consequence of an injury to cellular membranes, in particular those of the mitochondria, and to an impaired oxidative phosphorylation.