Why cellular stress suppresses adipogenesis in skeletal tissue,but is ineffective in adipose tissue: Control of mesenchymal cell differentiation via integrin binding sites in extracellular matrices

This Perspective addresses one of the major puzzles of adipogenesis in adipose tissue, namely its resistance to cellular stress. It introduces a concept of “density” of integrin binding sites in extracellular matrix, proposes a cellular signaling explanation for the observed effects of matrix elasticity and of cell shape on mesenchymal stem cell differentiation, and discusses how specialized integrin binding sites in collagen IV-containing matrices guard two pivotal physiological and evolutionary processes: stress-resistant adipogenesis in adipose tissues and preservation of pluripotency of mesenchymal stem-like cells in their storage niches. Finally, it proposes strategies to suppress adipogenesis in adipose tissues.     

Comparison of fecal glucocorticoid metabolite concentrations in hand- versus parent-reared whooping cranes (Grus americana)

Endangered whooping cranes (Grus americana) have been produced in captivity for reintroduction programs since the 1980s, using techniques such as artificial insemination, multiple clutching, and captive-rearing to speed recovery efforts. Chicks are often hand-reared (HR) by caretakers in crane costumes, socialized into groups and released together, unlike parent-reared (PR) cranes that are raised individually by a male/female crane pair and released singly. HR cranes historically exhibit greater morbidity rates during development than PR cranes, involving musculoskeletal and respiratory system disease, among others. We hypothesized that HR crane chicks exhibit a higher baseline fecal glucocorticoid metabolite (FGM) concentrations during the development compared with PR chicks. Fecal samples were collected between 15 and 70 days of age from HR (n = 15) and PR (n = 8) chicks to test for differences in FGM concentrations using a radioimmunoassay technique following ethanol extraction for steroids. Linear mixed model analysis suggests increasing age of the chick was associated with an increase in FGM (p < .001). Analysis also supported the interaction between rearing strategy and sex of the crane chick (p < .01). Female PR chicks had greater FGM concentrations than all other groups (PR male, p < .01; HR female, p < .001; and HR male, p < .001). This result suggests that there may be an effect of rearing strategy on stress physiology of whooping crane chicks, especially among females. Further research is needed to investigate whether the FGM concentrations are reflective of true differences in stress physiology of young cranes and whether this may impact health and conservation success.     

Transmission routes of Salmonella Typhimurium DT 104 between 14 cattle and pig herds in Denmark demonstrated by molecular fingerprinting

AIMS: Salmonella Typhimurium DT 104 is generally assumed to be spread by contact between live animals, e.g. by trading. The aim of the present study was to assess the importance of other routes of transmission in the dissemination of this bacterium. METHODS AND RESULTS: An outbreak among 14 cattle and pig herds located in a geographically narrow area in Denmark was investigated. Epidemiological information and disease history of the herds was obtained through interviews. Based on this, the hypothesis for horizontal spread was proposed, and these were confirmed by comparison of the pulsed field gel electrophoresis (PFGE) and the plasmid profiles of isolates obtained by continuous sampling over a period of almost 3 years. CONCLUSIONS: The study indicated that other routes might play an important role, than the trading of live animals, in the spread of S. Typhimurium DT 104 among livestock. SIGNIFICANCE AND IMPACT OF THE STUDY: Salmonella Typhimurium DT 104 infected herd might pose a significant risk to herds located within the same geographic area. In advising on how to avoid the spread of this bacterium, factors like person contacts, sharing of equipment and contaminated slurry should be focussed on in addition to infected animals.     

Thermoperiodic stem elongation involves transcriptional regulation of gibberellin deactivation in pea

The physiological basis of thermoperiodic stem elongation is as yet poorly understood. Thermoperiodic control of gibberellin (GA) metabolism has been suggested as an underlying mechanism. We have investigated the influence of different day and night temperature combinations on GA levels, and diurnal steady-state expression of genes involved in GA biosynthesis (LS, LH, NA, PSGA20ox1, and PsGA3ox1) and GA deactivation (PsGA2ox1 and PsGA2ox2), and related this to diurnal stem elongation in pea (Pisum sativum L. cv Torsdag). The plants were grown under a 12-h light period with an average temperature of 17 degrees C. A day temperature/night temperature combination of 13 degrees C/21 degrees C reduced stem elongation after 12 d by 30% as compared to 21 degrees C/13 degrees C. This was correlated with a 55% reduction of GA1. Although plant height correlated with GA1 content, there was no correlation between diurnal growth rhythms and GA1 content. NA, PsGA20ox1, and PsGA2ox2 showed diurnal rhythms of expression. PsGA2ox2 was up-regulated in 13 degrees C/21 degrees C (compared to 21 degrees C/13 degrees C), at certain time points, by up to 19-fold. Relative to PsGA2ox2, the expression of LS, LH, NA, PSGA20ox1, PsGA3ox1, and PsGA2ox1 was not or only slightly affected by the different temperature treatments. The sln mutant having a nonfunctional PsGA2ox1 gene product showed the same relative stem elongation response to temperature as the wild type. This supports the importance of PsGA2ox2 in mediating thermoperiodic stem elongation responses in pea. We present evidence for an important role of GA catabolism in thermoperiodic effect on stem elongation and conclude that PsGA2ox2 is the main mediator of this effect in pea.     

Neurotransmitter release regulated by a MALS-liprin-alpha presynaptic complex

Synapses are highly specialized intercellular junctions organized by adhesive and scaffolding molecules that align presynaptic vesicular release with postsynaptic neurotransmitter receptors. The MALS/Veli-CASK-Mint-1 complex of PDZ proteins occurs on both sides of the synapse and has the potential to link transsynaptic adhesion molecules to the cytoskeleton. In this study, we purified the MALS protein complex from brain and found liprin-alpha as a major component. Liprin proteins organize the presynaptic active zone and regulate neurotransmitter release. Fittingly, mutant mice lacking all three MALS isoforms died perinatally with difficulty breathing and impaired excitatory synaptic transmission. Excitatory postsynaptic currents were dramatically reduced in autaptic cultures from MALS triple knockout mice due to a presynaptic deficit in vesicle cycling. These findings are consistent with a model whereby the MALS-CASK-liprin-alpha complex recruits components of the synaptic release machinery to adhesive proteins of the active zone.     

Cloning and expression in Escherichia coli of the obtusifoliol 14α-demethylase of Sorghum bicolor (L.) Moench, a cytochrome P450 orthologous to the sterol 14α-demethylases (CYP51) from fungi and mammals

Obtusifoliol 14β-demethylase from Sorghum bicolor (L.) Moench has been cloned using a gene-specific probe generated using PCR primers designed from an internal 14 amino acid sequence. The sequence identifies sorghum obtusifoliol 14α-demethylase as a cytochrome P450 and it is assigned to the CYP51 family together with the sterol 14α-demethylases from fungi and mammals. The presence of highly conserved regions in the amino acid sequences, analogous substrates and the same metabolic role demonstrate that the sterol 14α-demethylases are orthologous enzymes. The sterol 14α-demethylases catalyse an essential step in sterol biosynthesis as evidenced by the absence of a 14α-methyl group in all known functional sterols. A functional sorghum obtusifoliol 14α-demethylase was expressed at high levels in Escherichia coli and purified using an efficient method based on temperature-induced Triton X-114 phase partitioning. The recombinant purified enzyme produced a type I spectrum with obtusifoliol as substrate. Reconstitution of purified recombinant enzyme with sorghum NADPH—cytochrome P450 reductase in dilaurylphosphatidylcholine micelles confirms that obtusifoliol 14α-demethylase catalyses the 14α-demethylation of obtusifoliol to 4α-methyl-5α-ergosta-8,14,24(28)-trien-3β-ol as evidenced by GC—MS. The isolation of a cDNA clone encoding the plant sterol 14α-demethylase, combined with the previously isolated cDNA clones for fungal and mammalian sterol 14α-demethylases, provides an important tool in the rational design of specific inhibitors towards the individual sterol 14α-demethylases.