cDNA microarray analysis of developing grape (Vitis vinifera cv. Shiraz) berry skin

Microarray analysis of Vitis vinifera cv. Shiraz developing berries has revealed the expression patterns of several categories of genes. Microarray slides were constructed from 4,608 PCR-amplified cDNA clones derived from a ripening grape berry cDNA library. The mRNA expression levels of the genes represented by these cDNAs were measured in flowers, week 2 post-flowering whole berries, week 5, week 8, week 10 (véraison, green berries), week 12 and week 13 berry skin. In addition, a comparison of RNA expression in pigmented and unpigmented berry skin at véraison (week 10) was undertaken. Image and statistical analysis revealed four sets of genes with distinctive and similar expression profiles over the course of berry development. The first set was composed of genes which had maximum RNA expression in flowers, followed by a steady decrease in expression. The most prominent group within this set were genes which have a role in photosynthesis. The second set of cDNAs was dominated by genes involved in flavonoid biosynthesis and had a peak of expression week 2 post-flowering. The data indicate co-ordinate regulation of flavonoid biosynthetic genes which code for the enzymes 4-coumarate-CoA ligase, chalcone synthase, chalcone isomerase, flavonone hydroxylase, anthocyanidin reductase and cytochrome b5. The third set of cDNAs exhibited maximum expression week 5 post-flowering, midway between flowering and véraison, a period of rapid berry growth. This set of cDNAs is dominated by genes which code for structural cell wall proteins. The fourth set of genes was dramatically up-regulated at véraison and remained up-regulated until 13 weeks post-flowering. This set of genes was composed of a diverse range of genes, a reflection of the complexity of ripening, most with no known function.     

Familial Danish dementia: co-existence of Danish and Alzheimer amyloid subunits (ADan AND A{beta}) in the absence of compact plaques

Familial Danish dementia is an early onset autosomal dominant neurodegenerative disorder linked to a genetic defect in the BRI2 gene and clinically characterized by dementia and ataxia. Cerebral amyloid and preamyloid deposits of two unrelated molecules (Danish amyloid (ADan) and beta-amyloid (Abeta)), the absence of compact plaques, and neurofibrillary degeneration indistinguishable from that observed in Alzheimer disease (AD) are the main neuropathological features of the disease. Biochemical analysis of extracted amyloid and preamyloid species indicates that as the solubility of the deposits decreases, the heterogeneity and complexity of the extracted peptides exponentially increase. Nonfibrillar deposits were mainly composed of intact ADan-(1-34) and its N-terminally modified (pyroglutamate) counterpart together with Abeta-(1-42) and Abeta-(4-42) in approximately 1:1 mixture. The post-translational modification, glutamate to pyroglutamate, was not present in soluble circulating ADan. In the amyloid fractions, ADan was heavily oligomerized and highly heterogeneous at the N and C terminus, and, when intact, its N terminus was post-translationally modified (pyroglutamate), whereas Abeta was mainly Abeta-(4-42). In all cases, the presence of Abeta-(X-40) was negligible, a surprising finding in view of the prevalence of Abeta40 in vascular deposits observed in sporadic and familial AD, Down syndrome, and normal aging. Whether the presence of the two amyloid subunits is imperative for the disease phenotype or just reflects a conformational mimicry remains to be elucidated; nonetheless, a specific interaction between ADan oligomers and Abeta molecules was demonstrated in vitro by ligand blot analysis using synthetic peptides. The absence of compact plaques in the presence of extensive neuro fibrillar degeneration strongly suggests that compact plaques, fundamental lesions for the diagnosis of AD, are not essential for the mechanism of dementia.     

Mitigating the squash effect: sloths breathe easily upside down

Sloths are mammals renowned for spending a large proportion of time hanging inverted. In this position, the weight of the abdominal contents is expected to act on the lungs and increase the energetic costs of inspiration. Here, we show that three-fingered sloths Bradypus variegatus possess unique fibrinous adhesions that anchor the abdominal organs, particularly the liver and glandular stomach, to the lower ribs. The key locations of these adhesions, close to the diaphragm, prevent the weight of the abdominal contents from acting on the lungs when the sloth is inverted. Using ventilation rate and body orientation data collected from captive and wild sloths, we use an energetics-based model to estimate that these small adhesions could reduce the energy expenditure of a sloth at any time it is fully inverted by almost 13%. Given body angle preferences for individual sloths in our study over time, this equates to mean energy saving of 0.8–1.5% across individuals (with individual values ranging between 0.01 and 8.6%) per day. Given the sloth''s reduced metabolic rate compared with other mammals and extremely low energy diet, these seemingly innocuous adhesions are likely to be important in the animal''s energy budget and survival.     

Assessment of Fetal Lung Maturity by Estimation of Amniotic Fluid Palmitic Acid

The measurement of palmitic acid in amniotic fluid has been shown to be a rapid means of assessing the lecithin concentration. The level of palmitic acid increases quickly when the fetal lung matures at about 35 weeks'' gestation, and the level in amniotic fluid obtained 24 hours or less before delivery clearly distinguishes which infants are likely to develop respiratory distress syndrome and which are mature.     

Lipid composition of cyanidium

The major lipids in Cyanidium caldarium Geitler are monogalactosyl diglyceride, digalactosyl diglyceride, plant sulfolipid, lecithin, phosphatidyl glycerol, phosphatidyl inositol, and phosphatidyl ethanolamine. Fatty acid composition varies appreciably among the lipids, but the major ones are palmitic acid, oleic acid, linoleic acid, and moderate amounts of stearic acid. Trace amounts of other acids in the C₁₄ to C₂₀ range were also present. Moderate amounts of linolenic acid were found in two strains, but not in a third. The proportion of saturated acid is relatively high in all lipids ranging from about a third in monogalactosyl diglyceride to three-fourths in sulfolipid. This may be a result of the high growth temperature. Lipases forming lysosulfolipid, and lysophosphatidyl glycerol are active in ruptured cells; galactolipid is degraded with loss of both acyl residues. Thus the lipid and fatty acid composition of Cyanidium more closely resembles that of green algae than that of the blue-green algae, although there are differences of possible phylogenetic interest.     

Plasma membrane calcium ATPase proteins as novel regulators of signal transduction pathways

Emerging evidence suggests that plasma membrane calcium ATPases (PMCAs) play a key role as regulators of calcium-triggered signal transduction pathways via interaction with partner proteins. PMCAs regulate these pathways by targeting specific proteins to cellular sub-domains where the levels of intracellular free calcium are kept low by the calcium ejection properties of PMCAs. According to this model, PMCAs have been shown to interact functionally with the calcium-sensitive proteins neuronal nitric oxide synthase, calmodulin-dependent serine protein kinase, calcineurin and endothelial nitric oxidase synthase. Transgenic animals with altered expression of PMCAs are being used to evaluate the physiological significance of these interactions. To date, PMCA interactions with calcium-dependent partner proteins have been demonstrated to play a crucial role in the pathophysiology of the cardiovascular system via regulation of the nitric oxide and calcineurin/nuclear factor of activated T cells pathways. This new evidence suggests that PMCAs play a more sophisticated role than the mere ejection of calcium from the cells, by acting as modulators of signaling transduction pathways.     

Arabidopsis poly(A) polymerase PAPS1 limits founder‐cell recruitment to organ primordia and suppresses the salicylic acid‐independent immune response downstream of EDS1/PAD4

Polyadenylation of pre‐mRNAs by poly(A) polymerase (PAPS) is a critical process in eukaryotic gene expression. As found in vertebrates, plant genomes encode several isoforms of canonical nuclear PAPS enzymes. In Arabidopsis thaliana these isoforms are functionally specialized, with PAPS1 affecting both organ growth and immune response, at least in part by the preferential polyadenylation of subsets of pre‐mRNAs. Here, we demonstrate that the opposite effects of PAPS1 on leaf and flower growth reflect the different identities of these organs, and identify a role for PAPS1 in the elusive connection between organ identity and growth patterns. The overgrowth of paps1 mutant petals is due to increased recruitment of founder cells into early organ primordia, and suggests that PAPS1 activity plays unique roles in influencing organ growth. By contrast, the leaf phenotype of paps1 mutants is dominated by a constitutive immune response that leads to increased resistance to the biotrophic oomycete Hyaloperonospora arabidopsidis and reflects activation of the salicylic acid‐independent signalling pathway downstream of ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1)/PHYTOALEXIN DEFICIENT4 (PAD4). These findings provide an insight into the developmental and physiological basis of the functional specialization amongst plant PAPS isoforms.