Ecosystem service bundles for analyzing tradeoffs in diverse landscapes.

A key challenge of ecosystem management is determining how to manage multiple ecosystem services across landscapes. Enhancing important provisioning ecosystem services, such as food and timber, often leads to tradeoffs between regulating and cultural ecosystem services, such as nutrient cycling, flood protection, and tourism. We developed a framework for analyzing the provision of multiple ecosystem services across landscapes and present an empirical demonstration of ecosystem service bundles, sets of services that appear together repeatedly. Ecosystem service bundles were identified by analyzing the spatial patterns of 12 ecosystem services in a mixed-use landscape consisting of 137 municipalities in Quebec, Canada. We identified six types of ecosystem service bundles and were able to link these bundles to areas on the landscape characterized by distinct social-ecological dynamics. Our results show landscape-scale tradeoffs between provisioning and almost all regulating and cultural ecosystem services, and they show that a greater diversity of ecosystem services is positively correlated with the provision of regulating ecosystem services. Ecosystem service-bundle analysis can identify areas on a landscape where ecosystem management has produced exceptionally desirable or undesirable sets of ecosystem services.

Papular dermatitis induced in guinea pigs by the biting midge Culicoides sonorensis (Diptera: Ceratopogonidae).

Histological, ultrastructural, and virological examinations were performed on abdominal skin from guinea pigs after a blood meal by colony-bred biting midges, Culicoides sonorensis. Small, superficial, cutaneous, crateriform ulcers with necrosis of superficial dermis developed at feeding sites and healed within 24-48 hours. Animals developed nonpruritic erythematous papules 5 days after feeding that persisted until the study ended at 12 days after feeding. Papules corresponded histologically to foci of epidermal hyperplasia and superficial interstitial dermatitis with intraepidermal micropustules and scattered intraepidermal polykaryons. The principal ultrastructural changes were spongiosis in germinal epithelium and neutrophilic-histiocytic exocytosis. No viral agents or broken mouthparts were identified in lesions. The dermatitis may represent a host reaction to persisting insect salivary secretion and should be considered as an additional consequence of blood feeding in future studies involving biting midges.

Linkage disequilibrium mapping of a type 1 diabetes susceptibility gene (IDDM7) to chromosome 2q31-q33.

The role of human chromosome 2 in type 1 diabetes was evaluated by analysing linkage and linkage disequilibrium at 21 microsatellite marker loci, using 348 affected sibpair families and 107 simplex families. The microsatellite D2S152 was linked to, and associated with, disease in families from three different populations. Our evidence localizes a new diabetes susceptibility gene, IDDM7, to within two centiMorgans of D2S152. This places it in a region of chromosome 2q that shows conserved synteny with the region of mouse chromosome 1 containing the murine type 1 diabetes gene, Idd5. These results demonstrate the utility of polymorphic microsatellites for linkage disequilibrium mapping of genes for complex diseases.

Prototyping a genetics deductive database.

We are developing a laboratory notebook system known as the Genetics Deductive Database. Currently our prototype provides storage for biological facts and rules with flexible access via an interactive graphical display. We have introduced a formal basis for the representation and reasoning necessary to order genome map data and handle the uncertainty inherent in biological data. We aim to support laboratory activities by introducing an experiment planner into our prototype. The Genetics Deductive Database is built using new database technology which provides an object-oriented conceptual model, a declarative rule language, and a procedural update language. This combination of features allows the implementation of consistency maintenance, automated reasoning, and data verification.

Polygenic control of autoimmune diabetes in nonobese diabetic mice.

Partial exclusion mapping of the nonobese (NOD) diabetic mouse genome has shown linkage of diabetes to at least five different chromosomes. We have now excluded almost all of the genome for the presence of susceptibility genes with fully recessive effects and have obtained evidence of linkage of ten distinct loci to diabetes or the prediabetic lesion, insulitis, indicative of a polygenic mode of inheritance. The relative importance of these loci and their interactions have been assessed using a new application of multiple polychotomous regression methods. A candidate disease gene, interleukin-2 (Il-2), which is closely linked to insulitis and diabetes, is shown to have a different sequence in NOD, including an insertion and a deletion of tandem repeat sequences which encode amino acid repeats in the mature protein.

Insulin gene region-encoded susceptibility to type 1 diabetes is not restricted to HLA-DR4-positive individuals.

Type 1 or insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease of the insulin-producing pancreatic beta-cells which is determined by both genetic and environmental factors. The major histocompatibility complex and the insulin gene region (INS) on human chromosomes 6p and 11p, respectively, contain susceptibility genes. Using a mostly French data set, evidence for linkage of INS to IDDM was recently obtained but only in male meioses (suggesting involvement of maternal imprinting) and only in HLA-DR4-positive diabetics. In contrast, we find evidence for linkage in both male and female meioses and that the effect of the susceptibility gene(s) in the INS region is not dependent on the presence of HLA-DR4.

Microsatellites for linkage analysis of genetic traits.

Microsatellites are tandem repeats of simple sequence that occur abundantly and at random throughout most eukaryotic genomes. Since they are usually less than 100 bp long and are embedded in DNA with unique sequence, they can be amplified in vitro using the polymerase chain reaction. Microsatellites are easy to clone and characterize and display considerable polymorphism due to variation in the number of repeat units. This polymorphism is sufficiently stable to use in genetic analyses. Microsatellites are therefore ideal markers for constructing high-resolution genetic maps in order to identify susceptibility loci involved in common genetic diseases.

The generation of a library of PCR-analyzed microsatellite variants for genetic mapping of the mouse genome.

Forty-three sequences containing simple sequence repeats or microsatellites were generated from an M13 library of total genomic mouse DNA. These sequences were analyzed for size variation using the polymerase chain reaction and gel electrophoresis without the need for radiolabeling. Seventy-two percent of the sequences showed allelic size variations between different inbred strains of mouse and the wild mouse, Mus spretus; and 53% showed variation between inbred strains. Thirty-seven percent were variant between B6/J and DBA/2J, and 81% of these were resolved using minigel agarose electrophoresis alone. This approach is a useful way of generating the large number of variants that are needed to create high resolution maps of the mouse genome.

Genetic analysis of autoimmune type 1 diabetes mellitus in mice.

Two genes, Idd-3 and Idd-4, that influence the onset of autoimmune type 1 diabetes in the nonobese diabetic mouse have been located on chromosomes 3 and 11, outside the chromosome 17 major histocompatibility complex. A genetic map of the mouse genome, analysed using the polymerase chain reaction, has been assembled specifically for the study. On the basis of comparative maps of the mouse and human genomes, the homologue of Idd-3 may reside on human chromosomes 1 or 4 and Idd-4 on chromosome 17.

Mononucleotide repeats are an abundant source of length variants in mouse genomic DNA.

Microsatellite sequences, such as dinucleotide repeats, show a high degree of polymorphism in eukaryotic DNA. These sequences are convenient as genetic markers and can be analyzed by the polymerase chain reaction (PCR). We have assessed the frequency of length variants in 18 mononucleotide repeats in mouse DNA and find that the variability is similar to that reported for dinucleotide repeats. Nine of the 18 repeat sequences (50%) have three or more alleles in the strains tested. Ten of these repeat sequences have been mapped using strain distribution patterns (SDPs) in recombinant inbred (RI) strains.

Additional microsatellite markers for mouse genome mapping.

Mouse sequence information from the EMBL and GenBank databases, published sequences and genomic clones have been analyzed for simple repetitive elements or microsatellites. Each microsatellite has been amplified by the polymerase chain reaction (PCR) as a single locus marker. PCR primers were designed from unique sequence flanking each repeat. Size variation of PCR products less than 750 base pairs (bp) between mouse strains has been determined using ethidium bromide-stained acrylamide or agarose gels. A further 74 newly characterized microsatellites are presented in this paper, bringing to 185 the total we have analyzed. Of these, 157/185 (85%) have more than one allele, 143/178 (80%) vary in length between C57BL/6J and Mus spretus, and 82/168 (49%) vary between DBA/2J and C57BL/6J. Microsatellites provide informative single locus probes for linkage analysis in the construction of a genetic map of the mouse genome.

Components of variance of some plasma constituents in patients with myocardial infarction.

Analytical, intra-individual, and inter-individual components of variance were estimated for eight plasma analytes in 20 patients who had myocardial infarction. Replicate analyses were performed on an average of 19.5 specimens obtained from each patient over a four-day period. Analytical variance was greater than 25% of the total variance for sodium, chloride, and bicarbonate levels but less than or equal to 12% for potassium, urea, creatinine, calcium, and albumin. Sodium, bicarbonate, urea, and creatinine concentrations showed strong individuality while those of potassium chloride, calcium, and albumin did not. Estimates of average intra-individual variation were larger than those previously documented; this is probably due to variation in sample collection, transport, and handling. Analytical goals were derived from intra-individual variation but it is not recommended that these be adopted in hospital laboratories.

Comparison of standardization techniques for colorimetric analyses on a centrifugal analyzer.

The influences of the mode of standardization and the type of standard on the precision of four mechanized methods performed on a centrifugal analyzer are described. Experimental results show that the mode of standardization -- variable, using a standard in each analytical batch, and constant, using a direct relationship between concentration and absorbance -- must be objectively selected. If the variable mode is chosen, the type and level of standard must be carefully chosen and absorbance of assays of the standard must be carefully monitored for good quality control. It is recommended that the optimum standardization technique and standard, where applicable, should be assessed and subsequently documented in evaluations of methods, kits and instruments.

Assessment of colorimetric enzymatic determination of triglyceride, by manual and centrifugal analyzer techniques, and comparison with a CDC standardized method.

We describe the assessment of an enzymatic method, with colorimetric detection, for the determination of triglyceride. Two commercial single vial reagent sets were evaluated, by manual and centrifugal analyzer techniques, and compared to a method which had attained standardized status from the Center for Disease Control (CDC). Precision and accuracy obtained on analysis of CDC reference materials, and precision obtained on analysis of plasma samples, did not fulfill the criteria of CDC. The precision met the criteria of the College of American Pathologists based upon intra-individual variation. Good correlation between the reagent set method and a continuous-flow method with prior extraction was evident but proportional and constant biases were found. The method would be suitable for routine use particularly if a centrifugal analyzer was employed. If a manual method was used it is recommended that blanks be performed on samples. The method had acceptable linearity. Use of a constant relationship between concentration and absorbance did not lead to improved performance characteristics.