Application of the Red List Index as an indicator of habitat change

For the first time ever, the International Union for Conservation of Nature Red List Index for habitat types was calculated for an entire country, Finland. The RLIs were based on species threat assessments from 2000 and 2010 and included habitat definitions for all 10,131 species of 12 organism groups. The RLIs were bootstrapped to track statistically significant changes. The RLI changes of species grouped by habitats were negative for all habitat types except for forests and rural biotopes which showed a stable trend. Trends of beetles and true bugs were positive in rural and forest habitats. Other 16 observed trends of species group and habitat combinations were negative. Several trends observed were in accordance with studies focusing on particular taxa and habitats, and drivers for their change. This study demonstrates the usefulness of the RLI as a tool for observing habitat change based on species threat assessment data.     

The environmental regulation of adult diapause in Drosophila littoralis

Drosophila littoralis overwinters in the adult stage in a reproductive diapause. During the warm season there are one or two generations in Finland. The diapause appears to be a prolongation of the post-eclosion immaturity of young females. The termination of diapause is controlled by a combination of adequate temperature and sufficiently long photophases. The diapausing status of females is ascertained by inspecting the developmental stage of their ovaries. In laboratory experiments the maturity of ovaries is not closely correlated with the receptivity of females.     

Enhancement of biotinidase activity in mouse serum by inhibitors of methylation

Summary DL-ethionine increases the activity of liver biotinidase, an enzyme which hydrolyzes biotinylesters and biotinylpeptides. Chronic DL-ethionine feeding increases transiently the activity of biotinidase in mouse and rat liver, after which it remains elevated in the serum. In the present work we show that both isomers of DL-ethionine are equally good enhancers of the liver biotinidase, while, 3-ethylthiopropionate, the toxic metabolite of DL-ethionine, has no effect on the biotinidase activity of either liver or serum. We have also employed two different combinations of inhibitors of the hydrolytic pathway of SAH, a transmethylation product and potent inhibitor of methylation. It was found that these inhibitors (EHNA and Ara-A, 2-deoxycoformycin and adenosine) increase the activity of serum biotinidase as was the case with ethionine. Because SAH does not ethylate biomolecules, these changes in biotinidase activity, which can not be preveneted by adenine, biotin or lecithin are most probably related to the inhibition of methylation.Abbreviations Ara-A 9--D-arabinofuranosyladenine - EHNA erythro-9-(2-hydroxy-3-nonyl)adenine - SAE S-adenosylethionine - SAH S-adenosylhomocysteine - SAM S-adenosylmethionine     

Infantile neuronal ceroid-lipofuscinosis is not an allelic form of Batten disease: exclusion of chromosome 16 region with linkage analyses

Infantile neuronal ceroid-lipofuscinosis (CLN1) is the form of neuronal ceroid-lipofuscinoses (NCL) with the earliest onset of symptoms. The locus of the most common form of these disorders, juvenile NCL (CLN3), has been mapped to chromosome 16. We report here linkage data of the same region in Finnish CLN1 families. Our results indicate that CLN1 is not allelic with CLN3 but represents a different locus, which is not located within about 70 cM in chromosome 16.     

Huntington disease in Finland: a molecular and genealogical study

Summary Huntington disease (HD) is found at exceptionally low frequency in the Finnish population. In this population, linkage disequilibrium was earlier established with markers from the D4S10 and D4S43 loci. We now report a continuation to the restriction fragment length polymorphism haplotype analysis, in combination with a genealogical study of all the Finnish HD families. When the HD pedigrees were systematically traced to the 18th century, only one consanguinity was found, and a high percentage (28%) of the families had foreign ancestors. The majority of the Finnish ancestors were localized to border regions or trade centers of the country following the old postal routes. The observed high risk haplotypes formed with markers from the D4S10 and D4S43 loci were evenly distributed among the HD families in different geographical locations. Consequently, the HD gene(s) has most probably arrived in Finland on several occasions via foreign immigrants during the last few centuries.     

Uridine enhances expression of the fragile X chromosome in human lymphocytes

Summary We have studied the effect of uridine on the expression of fragile X (fra[X]) in lymphocyte cultures established in the folate and thymidine deficient medium TC199. The results indicate that uridine enhances the expression of fra(X) and gives a higher mitotic rate. The excess of uridine during DNA synthesis might further promote the previously suggested cycle of misincorporation and removal of deoxyuridine monophosphate when the pool of deoxythymidine triphosphate is continuously depleted.     

Confirmation of the chromosomal localization of human lamp genes and their exclusion as candidate genes for Salla disease

Summary Salla disease is an inherited lysosomal storage disorder caused by accumulation of free sialic acid in the lysosomes. Lamp genes, lamp A and lamp B (lysosome associated membrane proteins), are the first known genes encoding for human lysosomal membrane proteins. Absence of linkage in a large group of families shows that lamp genes are not involved in Salla disease. The lamp genes were localized, using Southern hybridization in hamster — human hybrid cell panels, to chromosomes 13 (lamp A) and X (lamp B).     

Response of human fetal lymphocytes in xenogeneic mixed leukocyte culture: Phylogenetic and ontogenetic aspects

Cells from liver, thymus, and spleen of human fetuses at different stages of development were capable of a proliferation response against xenogeneic and allogeneic lymphocytes. The kinetics of fetal responses against rat lymphocytes were identical to those of fetal and adult responses against allogeneic cells. With all of the cell types studied, including adult lymphocytes, allogeneic responses were stronger than xenogeneic. Xenogeneic responses against lymphocytes from rat, mouse, or sheep were stronger than those against lymphocytes from rabbit, chicken, snake, or frog. These results are interpreted to indicate that recognition of foreign lymphocytes by human lymphocytes depends on the phylogenetic position of the species used as a source of stimulating cells. The degree of recognition decreases as the phylogenetic distance increases. Specific elimination of responding cells and restimulation with another cell population was used to study the specificity of proliferation responses against mouse and rat lymphocytes. Responses by prethymic liver cells from human fetuses were not due to the existence of specifically recognizing subpopulations. Thymus and spleen at 16 weeks' gestation contained specific subpopulations capable of differentiating between xenogeneic and allogeneic cells, as well as between xenogeneic cells with different intraspecies histocompatibility patterns. Generation of receptor diversity on T lymphocytes is discussed briefly in the light of these findings.     

Diagnosis of fragile X syndrome by direct mutation analysis

A total of 27 fragile X pedigrees consisting of over 100 nuclear families were analyzed by Southern blotting methods and probes StB12.3 and StB12.3xx to detect the expansion of the (CGG) _n repeat within the FMR-1 gene and the abnormal methylation pattern of the adjacent DNA region responsible for the fragile X syndrome. Clinical expression was found to be associated with the presence of a full mutation ( > 500 bp, associated with abnormal methylation) in all the males and 50% of the females studied, whereas individuals carrying a premutation ( = 100–700 bp) were normal. A preferential size increase in the enlarged (CGG) _n repeat was detected in successive generations, the instability being stronger when transmitted from a female than from a male. No expansion of the premutation to the full mutation occurred in the paternal transmissions, and the size increase was significantly smaller than in the maternal transmissions. This could partly explain the stability of the premutation through several generations in families with transmitting males. In the maternal transmissions, the risk of expansion of a premutation to a full mutation appeared to depend on its size. The critical maternal premutation size leading invariably to the full mutation was between = 175–200 bp. This is important for genetic counseling and also explains the commonly observed clustering of affected individuals in fragile X families.     

A Novel Mutation of the Fibrillin Gene Causing Ectopia Lentis

Ectopia lentis (EL), a dominantly inherited connective tissue disorder, has been genetically linked to the fibrillin gene on chromosome 15 (FBN1) in earlier studies. Here, we report the first EL mutation in the FBN1 gene confirming that EL is caused by mutations of this gene. So far, several mutations in the FBN1 gene have been reported in patients with Marfan syndrome (MFS). EL and MFS are clinically related but distinct conditions with typical manifestations in the ocular and skeletal systems, the fundamental difference between them being the absence of cardiovascular involvement in EL. We report a point mutation, cosegregating with the disease in the described family, that displays EL over four generations. The mutation changes a conserved glutamic acid residue in an EGF-like motif, which is the major structural component of the fibrillin and is repeated throughout the polypeptide. In vitro mutagenetic studies have demonstrated the necessity of an analogous glutamic acid residue for calcium binding in an EGF-like repeat of human factor IX. This provides a possible explanation for the role of this mutation in the disease pathogenesis.