Effects of replacing rapeseed meal with fava bean at 2 concentrate crude protein levels on feed intake, nutrient digestion, and milk production in cows fed grass silage-based diets.

The objective of this study was to evaluate the production and physiological responses of dairy cows to the substitution of fava bean for rapeseed meal at 2 protein supplementation levels in grass silage-based diets. We used 6 primiparous and 6 multiparous Finnish Ayrshire cows in a cyclic changeover trial with a 2×3 factorial arrangement of treatments. The experimental diets consisted of formic acid-treated timothy-meadow fescue silage and 3 isonitrogenous concentrates containing either rapeseed meal, fava bean, or a 1:1 mixture of rapeseed meal and fava bean at low and high inclusion rates, resulting in concentrate crude protein (CP) levels of 15.4 and 19.0% in dry matter. Silage dry matter intake decreased linearly when rapeseed meal was replaced with fava bean, the negative effect being more distinct at the high CP level than the low (-2.3 vs. -0.9kg/d, respectively). Similarly, milk and milk protein yields decreased linearly with fava bean, the change tending to be greater at the high CP level than the low. Yield of milk fat was lower for fava bean compared with rapeseed meal, the difference showing no interaction with CP level. Especially at the high CP level, milk urea concentration was higher with fava bean compared with rapeseed meal indicating better utilization of protein from the rapeseed meal. The apparent total-tract organic matter digestibility did not differ between treatments at the low CP level, but digestibility was higher for fava bean than for rapeseed meal at the high CP level. Plasma concentrations of essential amino acids, including methionine and lysine, were lower for fava bean than for rapeseed meal. Compared with rapeseed meal, the use of fava bean in dairy cow diets as the sole protein supplement decreased silage intake and milk production in highly digestible formic acid-treated grass silage-based diets.

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.

Mutations in the fibrillin gene responsible for dominant ectopia lentis and neonatal Marfan syndrome.

Mutations in the gene coding for fibrillin on chromosome 15 (FBN1) are known to cause Marfan syndrome (MFS). A related disorder, dominant ectopia lentis (EL), has also been linked genetically to this locus. We now describe ten novel mutations of FBN1 resulting in strikingly different phenotypes. In addition to classic MFS, FBN1 mutations also give rise to EL and a severe neonatal form of MFS. Interestingly, the neonatal MFS mutations are clustered in one particular region of FBN1, possibly providing new insights into genotype-phenotype comparisons.

Two mutations in Marfan syndrome resulting in truncated fibrillin polypeptides.

Biochemical and molecular genetic studies have recently suggested that mutations in the gene coding for fibrillin on chromosome 15 result in Marfan syndrome. To our knowledge, only one mutation in the fibrillin gene has been published. Here we report the results of screening 20 unrelated MFS patients for mutations in fibrillin cDNA by the single-strand conformation polymorphism technique. We found two mutations, both of which appear in the heterozygote form and code for a shortened fibrillin polypeptide. The first mutation is a large in-frame deletion of 366 bases of the fibrillin mRNA, shown to result in a truncated but secreted polypeptide found in the fibroblast culture of the patient. The second mutation is a G-to-A transition resulting in the substitution of a stop codon for a tryptophan codon and thus predicting the premature termination of the polypeptide chain. We screened 60 other, unrelated MFS patients for these mutations as well as for the previously reported mutation (arginine-239 to proline) and found none of the three mutations in any of these patients. These data suggest that most MFS families carry their own distinct mutation.

Linkage map of the chromosomal region surrounding the infantile neuronal ceroid lipofuscinosis on 1p.

The neuronal ceroid lipofuscinoses (NCLs) of childhood are divided into 3 main types according to age-of-onset, clinical course, and neurophysiological and neuropathological findings: infantile, late infantile, and juvenile. All forms are inherited as an autosomal recessive trait, and their biochemical background is still unknown. The infantile type (INCL) with the earliest age-of-onset and the most severe clinical course, occurs in Finland with an incidence of 1:20,000, i.e., 116 patients have been found in our country up to now, whereas only about 50 cases have been reported from other parts of the world. Earlier we reported the linkage of INCL to the short arm of chromosome 1. Here we describe a more precise linkage map of this area. Our current map places the INCL mutation between D1S57 and D1S79; D1S7 has so far shown no recombination events between the marker and the disease (lod score 4.55 at theta = 0.00). Our material includes 64% of all living patients in Finland, and no linkage disequilibrium of haplotypes is seen, using the 2 physically close markers D1S57 and D1S79. This finding as well as our LINKMAP analyses suggest that the distance between the disease locus and the flanking markers is about 3-4 cm.

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

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).

DNA-based prenatal diagnosis of the infantile form of neuronal ceroid lipofuscinosis (INCL, CLN1).

Eleven fetuses at risk for the infantile form of neuronal ceroid lipofuscinosis (INCL, CLN1) were studied using DNA markers and the results were compared with the results of electron microscopy (EM) of chorionic villus specimens from pregnancies in the first or early second trimester of pregnancy. In four cases, the prenatal diagnosis was made independently with both methods, and in seven cases, the EM diagnosis was confirmed postnatally or from autopsy material using RFLP analysis. The two methods gave concordant results in all cases. The DNA analysis based on RFLP haplotypes also for the first time facilitates reliable carrier diagnostics. RFLP analysis based on polymorphic markers closely linked to the INCL locus is now available for prenatal diagnosis of this fatal brain disease, whose biochemical background is totally unknown and for which no treatment is available.

Infantile form of neuronal ceroid lipofuscinosis (CLN1) maps to the short arm of chromosome 1.

The neuronal ceroid lipofuscinoses (CLNs) are one of the most common progressive encephalopathies of childhood in Western countries. They are divided into three main types: infantile, late infantile, and juvenile. The inheritance of all forms is autosomal recessive, and the biochemical background is totally unknown. The infantile type (CLN1) demonstrates the earliest onset of symptoms and the most severe clinical course. CLN1 is enriched in the Finnish population with incidence of 1:20,000, and only about 50 cases have been reported from other parts of the world. We have collected 15 Finnish CLN1 families with one or two diseased children for a linkage analysis with polymorphic probes randomly localized on human chromosomes. After studying 42 polymorphic protein and DNA markers, we found definitive proof of linkage with three different probes on the short arm of chromosome 1, with maximum lod scores of 3.38 at theta = 0.00 (0.00-0.08) for D1S57 (pYNZ2), 3.56 at theta = 0.00 (0.00-0.09) for D1S7 (lambda MS1), and 3.56 at theta = 0.00 (0.00-0.11) for D1S79 (pCMM8). With the assignment of the CLN1 gene, our study demonstrates the power of multiallelic VNTR probes in the search for linkage of a rare recessive disorder using limited family material.

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.