Copy number variations in three children with sudden infant death.

Sudden death of an infant is a devastating event that needs an explanation. When an explanation cannot be found, the case is labeled as sudden infant death syndrome or unclassified sudden infant death. The influence of genetic factors has been recognized for sudden infant death, but copy number variations (CNVs) as potential risk factors have not been evaluated yet. Twenty-seven families were enrolled in this study. The tissue specimens from deceased children were obtained and array-based comparative genomic hybridization (array-CGH) experiments were performed on the genomic DNA isolated from these specimens using Agilent Technologies Custom 4 x 44K arrays. Quantitative polymerase chain reaction experiments were performed to confirm the overlapping duplication and deletion region in two different cases. A de novo CNV is detected in 3 of 27 cases (11%). In case 1, an approximately 3-Mb (chr 8: 143,211,215-qter) duplication on 8q24.3-qter and a 4.4-Mb deletion on the 22q13.3-qter (chr 22: 45,047,068-qter) were detected. Subtelomeric chromosome analysis of the father and the surviving sibling of case 1 showed a balanced reciprocal translocation, 46,XY,t(8;22)(q24.3;q13.3). A 240-kb (chr 6: 26,139,810-26,380,787) duplication and a 1.9-Mb deletion (chr 6: 26,085,971-27,966,150) at chromosome 6p22 were found in cases 2 and 3, respectively. Array-CGH and conventional cytogenetic studies did not reveal the observed CNVs in the parents and the siblings of cases 2 and 3. The detected CNVs in cases 2 and 3 encompassed several genes including the major histone cluster genes. Array-CGH analysis may be beneficial during the investigations after sudden infant death.

Developmentally regulated proteases from the basidiomycete Schizophyllum commune.

The basidiomycete Schizophyllum commune produces three chromatographically distinguishable proteases which are capable of attack on a variety of other enzymes from S. commune and other sources. These proteases, which are produced during a specific phase of the development cycle, exhibit typical enzyme kinetic patterns, are active in the neutral to weakly alkaline pH range and are inhibited by phenylmethylsulfonyl fluoride, soybean trypsin inhibitor, and ovomucoid. No pattern of specificity toward the test enzymes could be discerned. The proteases co-purify with the activity which causes the increase in cold lability of S. commune phosphoglucomutase reported previously. In addition, one of the protease enzymes could be purified to the point where it had no significant ability to release trichloroacetic acid products from denatured substrates at pH 3 or pH 7. When undenatured hemoglobin was used as a substrate, the purified protease releases a relatively large molecular weight nonheme peptide. Relatively large peptides are also formed after proteolysis of rabbit muscle phosphoglucomutase. These results suggest that the protease carries out only limited proteolysis.

Cell wall metabolism during fruiting of the basidiomycete Schizophyllum commune.

During the development of fruit bodies of the basidiomycete Schizophyllum commune, the alkali-insoluble (R glucan) and alkali-soluble (S glucan) cell wall fractions are synthesized during the entire course of morphogenesis. The water soluble glucan (WSG) is not synthesized after an early stage. There is also a relative increase in the proportion of S glucan during development with appears related to a change in the proportion of the components synthesized. Data are also presented to show that several fruiting mutants also have specific cell wall differences, and that there is a significant contribution to cell wall structure by genes which do not cause a macroscopically observable change in phenotype.

Studies on basidiospore development in Schizophyllum commune.

The time required for synthesis of the spore components and the effect of different environmental conditions on basidiospore production were studied in the basidiomycete Schizophyllum commune. Both exogenous glucose and storage materials were used in the synthesis of spore components, which took 40 to 45 h to complete. A temperature of 30 degrees C, the presence of 5% CO2, a continuous supply of glucose, or a lack of exogenous glucose, had no effect on the rate of spore production. Light, however, was required for sporulation. Darkness inhibited sporulation between karyogamy and the initiation of meiosis: complete inhibition occurred after 48 h in the dark. Spores were produced 5 h after release from dark inhibition.

Developmental regulation of amylase activity during fruiting of Schizophyllum commune.

During the development of fruit bodies of Schizophyllum commune there is a minimum 10- to 15-fold increase in amylase activity. There is little or no activity in homokaryons or dikaryons. The activity is found early after the onset of morphogenesis and increases until the fruit bodies are mature. Inhibition studies with CO(2) indicate that the activity is directly associated with fruiting, as a change from fruiting to vegetative growth of the dikaryotic mycelium leads to a loss in activity, whereas the already formed fruit bodies show no loss. The activity is unaffected by the level of glucose in the medium. Evidence is presented, based on the mode of starch degradation and on yield and inhibition studies, that the enzyme is a glucoamylase.