Laboratory and field growth studies of commercial strains ofEucheuma denticulatum andKappaphycus alvarezii in the Philippines

Daily growth rates of 0.1 to 8.4% d^-1 for the brown form and 0.2 to 6.3% d^-1 of the green form were measured for 3 to 5-cm long branches of the tropical red seaweedKappaphycus alvarezii cultured in the laboratory. Highest growth rates were found using inexpensive enrichments such as soil water and coconut water supplemented with 0.7 mM N and 13 µM P and with a liquid fertilizer, Algafer, produced from seaweeds in the Philippines. Laboratory grown branches of bothK. alvarezii andEucheuma denticulatum transplanted to rafts in the field showed daily growth rates of 4.4 to 8.9% d^-1, as high or higher than other reported growth rates. The studies, carried out in the Philippines, demonstrate the viability and high yield of laboratory cultivars and methods to keep laboratory culture costs low.     

Initiation of sporulation in Saccharomyces cerevisiae. Mutations causing derepressed sporulation and G1 arrest in the cell division cycle

Mutants of Saccharomyces cerevisiae that are derepressed for meiosis and spore formation have been isolated and characterized genetically. All are the result of single, recessive nuclear mutations that fall into four linkage groups. Three of these groups are represented by spd1, spd3 and spd4 mutations, which in homozygous diploids confer poor growth and extensive sporulation on a range of non-fermentable media. Haploids carrying any of these mutations are arrested under these conditions in the G1 phase of the cell division cycle as large unbudded cells. The alleles of the spd2 mutation complemented all other mutations but were very closely linked to the spd1 locus. The fourth linkage group was represented by a mutation conferring temperature-sensitive growth and derepressed sporulation on homozygous diploids grown between 25 degrees C and 30 degrees C on media containing galactose or glycerol, but not glucose, as energy source. Above 30 degrees C this mutant lysed on all media. The mutation it carried failed to complement available cdc25 mutations. These data bring to five the number of loci at which mutation can lead to derepressed sporulation (spd1, spd3, spd4, cdc25 and cdc35). The spd1 locus has been mapped 13.9 cM to the left of the centromere on chromosome XV, adjacent to the SUP3 gene. Diploid strains homozygous for spd mutations are genetically unstable, giving rise to asporogenous mutants at high frequency, usually as the result of a second mutation unlinked to the spd mutation. Diploids homozygous for these mutations, and for spd mutations, show an altered regulation of the formulation of at least three polypeptides normally subject to carbon source repression.     

A smart device inertial-sensing method for gait analysis

The purpose of this study was to establish and cross-validate a method for analyzing gait patterns determined by the center of mass (COM) through inertial sensors embedded in smart devices. The method employed an extended Kalman filter in conjunction with a quaternion rotation matrix approach to transform accelerations from the object onto the global frame. Derived by double integration, peak-to-trough changes in vertical COM position captured by a motion capture system, inertial measurement unit, and smart device were compared in terms of averaged and individual steps. The inter-rater reliability and levels of agreement for systems were discerned through intraclass correlation coefficients (ICC) and Bland–Altman plots. ICCs corresponding to inter-rater reliability were good-to-excellent for position data (ICCs,.80–.95) and acceleration data (ICCs,.54–.81). Levels of agreements were moderate for position data (LOA, 3.1–19.3%) and poor for acceleration data (LOA, 6.8%–17.8%). The Bland–Altman plots, however, revealed a small systematic error, in which peak-to-trough changes in vertical COM position were underestimated by 2.2 mm; the Kalman filter?s accuracy requires further investigation to minimize this oversight. More importantly, however, the study?s preliminary results indicate that the smart device allows for reliable COM measurements, opening up a cost-effective, user-friendly, and popular solution for remotely monitoring movement. The long-term impact of the smart device method on patient rehabilitation and therapy cannot be underestimated: not only could healthcare expenditures be curbed (smart devices being more affordable than today‘s motion sensors), but a more refined grasp of individual functioning, activity, and participation within everyday life could be attained.     

Humans seek clues from closest kin

Genomes: As researchers promote the value of different species in the competition for rare sequencing dollars, primate genomics can still make a case in the appeal for those funds, reports Heather Dawes.     

Geographical distribution and disease associations of the CD45 exon 6 138G variant

CD45 is crucial for normal lymphocyte signalling, and altered CD45 expression has major effects on immune function. Both mice and humans lacking CD45 expression are severely immunodeficient, and single-nucleotide polymorphisms in the CD45 gene that cause altered splicing have been associated with autoimmune and infectious diseases. Recently, we identified an exon 6 A138G polymorphism resulting in an increased proportion of activated CD45RO T cells and altered immune function. Here we report a significantly reduced frequency of the 138G allele in hepatitis C Japanese patients and a possibly reduced frequency in type I diabetes. The allele is widely distributed in the Far East and India, indicating that it may have a significant effect on disease burden in a large part of the human population.     

The Endosomal Protein-Sorting Receptor Sortilin Has a Role in Trafficking α-1 Antitrypsin

Up to 1 in 3000 individuals in the United States have α-1 antitrypsin deficiency, and the most common cause of this disease is homozygosity for the antitrypsin-Z variant (ATZ). ATZ is inefficiently secreted, resulting in protein deficiency in the lungs and toxic polymer accumulation in the liver. However, only a subset of patients suffer from liver disease, suggesting that genetic factors predispose individuals to liver disease. To identify candidate factors, we developed a yeast ATZ expression system that recapitulates key features of the disease-causing protein. We then adapted this system to screen the yeast deletion mutant collection to identify conserved genes that affect ATZ secretion and thus may modify the risk for developing liver disease. The results of the screen and associated assays indicate that ATZ is degraded in the vacuole after being routed from the Golgi. In fact, one of the strongest hits from our screen was Vps10, which can serve as a receptor for the delivery of aberrant proteins to the vacuole. Because genome-wide association studies implicate the human Vps10 homolog, sortilin, in cardiovascular disease, and because hepatic cell lines that stably express wild-type or mutant sortilin were recently established, we examined whether ATZ levels and secretion are affected by sortilin. As hypothesized, sortilin function impacts the levels of secreted ATZ in mammalian cells. This study represents the first genome-wide screen for factors that modulate ATZ secretion and has led to the identification of a gene that may modify disease severity or presentation in individuals with ATZ-associated liver disease.