Lifestyle intervention leading to moderate weight loss normalizes postprandial triacylglycerolemia despite persisting obesity

Obesity is associated with impaired postprandial triacylglycerolemia, an independent risk factor for cardiovascular disease. Given that obesity is hard to treat, efforts should focus on treating its comorbidities. We aimed to investigate whether moderate weight loss normalizes postprandial triacylglycerol (TAG) concentrations, in the absence of the acute effects of negative energy balance. For this purpose, postprandial lipemia was investigated in eight obese but otherwise healthy, sedentary men (age: 41.3 ± 4.1 years, BMI: 36.5 ± 1.6 kg·m(-2)), once before and again after a 10% weight loss followed by ≥4 weeks of weight maintenance, and was compared with that of eight age-matched healthy lean men (BMI: 24.7 ± 0.6 kg·m(-2)). Dietary intervention consisted of reduced carbohydrate and saturated fat intake and increased monounsaturated fat intake. Obese volunteers were advised to increase physical activity using pedometers to record daily activity. Postprandial triacylglycerolemia after weight loss was reduced by 27-46% (P < 0.05), and became similar to that of lean men despite persisting obesity (BMI after weight loss: 32.9 ± 1.5 kg·m(-2)). Reduction in postprandial TAG responses was inversely correlated with the decrease in postprandial insulin sensitivity index (ISI) after weight loss (r = -0.714, P = 0.047). We conclude that moderate weight loss induced by a low-carbohydrate and saturated fat diet and a slight increase in daily physical activity normalizes postprandial triacylglycerolemia in obese men, independently of acute diet-induced negative energy balance, and possibly through enhancement of insulin action.     

Mutations in SLC33A1 cause a lethal autosomal-recessive disorder with congenital cataracts, hearing loss, and low serum copper and ceruloplasmin

Low copper and ceruloplasmin in serum are the diagnostic hallmarks for Menkes disease, Wilson disease, and aceruloplasminemia. We report on five patients from four unrelated families with these biochemical findings who presented with a lethal autosomal-recessive syndrome of congenital cataracts, hearing loss, and severe developmental delay. Cerebral MRI showed pronounced cerebellar hypoplasia and hypomyelination. Homozygosity mapping was performed and displayed a region of commonality among three families at chromosome 3q25. Deep sequencing and conventional sequencing disclosed homozygous or compound heterozygous mutations for all affected subjects in SLC33A1 encoding a highly conserved acetylCoA transporter (AT-1) required for acetylation of multiple gangliosides and glycoproteins. The mutations were found to cause reduced or absent AT-1 expression and abnormal intracellular localization of the protein. We also showed that AT-1 knockdown in HepG2 cells leads to reduced ceruloplasmin secretion, indicating that the low copper in serum is due to reduced ceruloplasmin levels and is not a sign of copper deficiency. The severity of the phenotype implies an essential role of AT-1 in proper posttranslational modification of numerous proteins, without which normal lens and brain development is interrupted. Furthermore, AT-1 defects are a new and important differential diagnosis in patients with low copper and ceruloplasmin in serum.     

'Click' synthesis of a triazole-based inhibitor of Met functions in cancer cells

The use of Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition permitted the synthesis of a new compound that is able to inhibit the HGF-induced scattering of MDCK (epithelial cells) and in vitro tumorigenesis of H1437 (non-small-cell lung cancer) and GTL-16 (human gastric carcinoma). In agreement with biochemical and biological results, docking studies within the ATP binding site of Met suggested for the new synthesized compound a binding mode similar to that of the active compound Triflorcas previously reported.     

Methyl Jasmonate Increases the Tropane Alkaloid Scopolamine and Reduces Natural Herbivory in Brugmansia suaveolens: Is Scopolamine Responsible for Plant Resistance?

The tropane alkaloid (TA) scopolamine is suggested to protect Brugmansia suaveolens (Solanaceae) against herbivorous insects. To test this prediction in a natural environment, scopolamine was induced by methyl jasmonate (MJ) in potted plants which were left 10?days in the field. MJ-treated plants increased their scopolamine concentration in leaves and herbivory decreased. These findings suggest a cause?Ceffect relationship. However, experiments in laboratory showed that scopolamine affect differently the performance of the specialist larvae of the ithomiine butterfly Placidina euryanassa (C. Felder & R. Felder) and the generalist fall armyworm Spodoptera frugiperda (J. E. Smith): the specialist that sequester this TA from B. suaveolens leaves was not negatively affected, but the generalist was. Therefore, scopolamine probably acts only against insects that are not adapted to TAs. Other compounds that are MJ elicited may also play a role in plant resistance against herbivory by generalist and specialist insects, and deserve future investigations.     

Translation inhibitors induce cell death by multiple mechanisms and Mcl-1 reduction is only a minor contributor

There is significant interest in treating cancers by blocking protein synthesis, to which hematological malignancies seem particularly sensitive. The translation elongation inhibitor homoharringtonine (Omacetaxine mepesuccinate) is undergoing clinical trials for chronic myeloid leukemia, whereas the translation initiation inhibitor silvestrol has shown promise in mouse models of cancer. Precisely how these compounds induce cell death is unclear, but reduction in Mcl-1, a labile pro-survival Bcl-2 family member, has been proposed to constitute the critical event. Moreover, the contribution of translation inhibitors to neutropenia and lymphopenia has not been precisely defined. Herein, we demonstrate that primary B cells and neutrophils are highly sensitive to translation inhibitors, which trigger the Bax/Bak-mediated apoptotic pathway. However, contrary to expectations, reduction of Mcl-1 did not significantly enhance cytotoxicity of these compounds, suggesting that it does not have a principal role and cautions that strong correlations do not always signify causality. On the other hand, the killing of T lymphocytes was less dependent on Bax and Bak, indicating that translation inhibitors can also induce cell death via alternative mechanisms. Indeed, loss of clonogenic survival proved to be independent of the Bax/Bak-mediated apoptosis altogether. Our findings warn of potential toxicity as these translation inhibitors are cytotoxic to many differentiated non-cycling cells.     

Collision avoidance in commercial aircraft Free Flight via neural networks and non-linear programming

In recent years there has been a great effort to convert the existing Air Traffic Control system into a novel system known as Free Flight. Free Flight is based on the concept that increasing international airspace capacity will grant more freedom to individual pilots during the enroute flight phase, thereby giving them the opportunity to alter flight paths in real time. Under the current system, pilots must request, then receive permission from air traffic controllers to alter flight paths. Understandably the new system allows pilots to gain the upper hand in air traffic. At the same time, however, this freedom increase pilot responsibility. Pilots face a new challenge in avoiding the traffic shares congested air space. In order to ensure safety, an accurate system, able to predict and prevent conflict among aircraft is essential. There are certain flight maneuvers that exist in order to prevent flight disturbances or collision and these are graded in the following categories: vertical, lateral and airspeed. This work focuses on airspeed maneuvers and tries to introduce a new idea for the control of Free Flight, in three dimensions, using neural networks trained with examples prepared through non-linear programming.     

MECP2 genomic structure and function: insights from ENCODE

MECP2, a relatively small gene located in the human X chromosome, was initially described with three exons transcribing RNA from which the protein MeCP2 was translated. It is now known to have four exons from which two isoforms are translated; however, there is also evidence of additional functional genomic structures within MECP2, including exons potentially transcribing non-coding RNAs. Accompanying the recognition of a higher level of intricacy within MECP2 has been a recent surge of knowledge about the structure and function of human genes more generally, to the extent that the definition of a gene is being revisited. It is timely now to review the published and novel functional elements within MECP2, which is proving to have a complexity far greater than was previously thought.     

Engineering a camelid antibody fragment that binds to the active site of human lysozyme and inhibits its conversion into amyloid fibrils

A single-domain fragment, cAb-HuL22, of a camelid heavy-chain antibody specific for the active site of human lysozyme has been generated, and its effects on the properties of the I56T and D67H amyloidogenic variants of human lysozyme, which are associated with a form of systemic amyloidosis, have been investigated by a wide range of biophysical techniques. Pulse-labeling hydrogen-deuterium exchange experiments monitored by mass spectrometry reveal that binding of the antibody fragment strongly inhibits the locally cooperative unfolding of the I56T and D67H variants and restores their global cooperativity to that characteristic of the wild-type protein. The antibody fragment was, however, not stable enough under the conditions used to explore its ability to perturb the aggregation behavior of the lysozyme amyloidogenic variants. We therefore engineered a more stable version of cAb-HuL22 by adding a disulfide bridge between the two beta-sheets in the hydrophobic core of the protein. The binding of this engineered antibody fragment to the amyloidogenic variants of lysozyme inhibited their aggregation into fibrils. These findings support the premise that the reduction in global cooperativity caused by the pathogenic mutations in the lysozyme gene is the determining feature underlying their amyloidogenicity. These observations indicate further that molecular targeting of enzyme active sites, and of protein binding sites in general, is an effective strategy for inhibiting or preventing the aberrant self-assembly process that is often a consequence of protein mutation and the origin of pathogenicity. Moreover, this work further demonstrates the unique properties of camelid single-domain antibody fragments as structural probes for studying the mechanism of aggregation and as potential inhibitors of fibril formation.