An active site-tyrosine-containing heptapeptide from D-amino acid oxidase

The flavoenzyme D-amino acid oxidase (Eo) is rapidly chlorinated by N-chloro-D-leucine (Rudie, N.G., Porter, D.J.T., and Bright, H.J. (1980) J. Biol. Chem. 255, 498-508). We have carried out chymotryptic digestion of E0-36Cl2 and find that all of the radiolabel is located in a heptapeptide having [3.5-36Cl2]chlorotyrosine as the COOH-terminal residue. This heptapeptide, having the sequence -Asp-Leu-Glu-Arg-Gly-Ile-Tyr-, is located within a larger fragment obtained previously from cyanogen bromide cleavage of E0. These results demonstrate that the target for chlorination in E0 must be a single tyrosine residue and provide, when taken together with previous findings, the first clear evidence for the identity and location of an active site residue in the polypeptide chain of D-amino oxidase.     

Spotted hyaena Crocuta crocuta feeding ecology and selectivity of large herbivorous prey in the Namib desert

We have investigated the relationship between spotted hyaenas in the south Namib Desert and large herbivorous prey and have summarized an updated overview of predator‐prey relationships in this resource‐limited arid environment. Over the 52‐month study, we recorded the densities (#/km⁻², ±SE) of the four local large herbivorous prey species: gemsbok (1.229, ±0.50), springbok (1.352, ±0.48), ostrich (0.648, ±0.23), and greater kudu (0.343, ±0.00). A fecal analysis was performed on 146 collected spotted hyaena scats, and prey items were identified and hairs cross‐follicle analyzed to the species level. Spotted hyaena diet at the study area remained opportunistic with 240 identified prey items representing eight differing prey species being recorded, ranging from ostrich eggs to large ungulates. The Ivlev''s Electivity Index was used to determine which large herbivorous prey was most selected for. Although gemsbok had a higher representation of prey items in the sampled scats, all sampled large herbivorous prey species scored below 0 and are thus generally avoided in relation to their availability in the environment. If any prey preferences are expressed by spotted hyaena in the Namib, it can be presumed to be a nonsampled prey species. We therefore promote further detailed investigations into all other prey species present, and seasonal variations of prey densities and scat sampling, within the study environment.     

A Clinical Evaluation of Statin Pleiotropy: Statins Selectively and Dose-Dependently Reduce Vascular Inflammation

Statins are thought to reduce vascular inflammation through lipid independent mechanisms. Evaluation of such an effect in atherosclerotic disease is complicated by simultaneous effects on lipid metabolism. Abdominal aortic aneurysms (AAA) are part of the atherosclerotic spectrum of diseases. Unlike atherosclerotic occlusive disease, AAA is not lipid driven, thus allowing direct evaluation of putative anti-inflammatory effects. The anti-inflammatory potency of increasing doses (0, 20 or 40 mg/day) simvastatin or atorvastatin was evaluated in 63 patients that were at least 6 weeks on statin therapy and who underwent open AAA repair. A comprehensive analysis using immunohistochemistry, mRNA and protein analyses was applied on aortic wall samples collected during surgery. The effect of statins on AAA growth was analyzed in a separate prospective study in incorporating 142 patients. Both statins equally effectively and dose-dependently reduced aortic wall expression of NFκB regulated mediators (i.e. IL-6 (P<0.001) and MCP-1 (P<0.001)); shifted macrophage polarization towards a M2 phenotype (P<0.0003); selectively reduced macrophage-related markers such as cathepsin K and S (P<0.009 and 0.0027 respectively), and ALOX5 (P<0.0009), and reduced vascular wall NFκB activity (40 mg/day group, P<0.016). No effect was found on other cell types. Evaluation of the clinical efficacy of statins to reduce AAA progression did not indicate an effect of statins on aneurysm growth (P<0.337). Hence, in the context of AAA the clinical relevance of statins pleiotropy appears minimal.     

Nitro analogs of substrates for adenylosuccinate synthetase and adenylosuccinate lyase

The reactivities of the nitro analogs of the substrates of adenylosuccinate synthetase and adenylosuccinate lyase, the enzymes which catalyze the penultimate and last step, respectively, in the pathway for AMP biosynthesis have been examined. Alanine-3-nitronate, an aspartate analog, was a substrate for the synthetase from Azotobacter vinelandii, having a $\text{k}{}_{\mathrm{<mtext>cat</mtext>}}\text{K}{}_{\mathrm{m}}$ which was ~30% that for aspartate. The product of this reaction was N⁶-(l-1-carboxy-2-nitroethyl)-AMP. Of nine other substrate analogs tested, only cysteine sulfinate (having 5.5% of the activity of aspartate) was reactive. These results demonstrate the strict requirement of the synthetase for a negatively charged substituent, with a carboxylate-like geometry, at the β-carbon of the α-amino acid substrate. The lyase, purified to homogeneity from brewer's yeast by a new procedure, did not utilize N⁶-(l-1-carboxy-2-nitroethyl)-AMP as a substrate. However, the nitronate form of this analog was a good inhibitor of the lyase ($\text{K}{}_{\mathrm{m}}\text{K}{}_{\mathrm{i}}\text{= 28}$ when compared to adenylosuccinate), suggesting that it mimics a carbanionic intermediate in the reaction pathway. The avid binding of bromphenol blue by the lyase (_i = 0.95 μM) was used for active site titrations and for displacement of the enzyme, in the purification protocol, from blue Sepharose.     

Impaired attribution of emotion to facial expressions in anxiety and major depression

Background

Recognition of others'' emotions is an important aspect of interpersonal communication. In major depression, a significant emotion recognition impairment has been reported. It remains unclear whether the ability to recognize emotion from facial expressions is also impaired in anxiety disorders. There is a need to review and integrate the published literature on emotional expression recognition in anxiety disorders and major depression.

Methodology/Principal Findings

A detailed literature search was used to identify studies on explicit emotion recognition in patients with anxiety disorders and major depression compared to healthy participants. Eighteen studies provided sufficient information to be included. The differences on emotion recognition impairment between patients and controls (Cohen''s d) with corresponding confidence intervals were computed for each study. Over all studies, adults with anxiety disorders had a significant impairment in emotion recognition (d = −0.35). In children with anxiety disorders no significant impairment of emotion recognition was found (d = −0.03). Major depression was associated with an even larger impairment in recognition of facial expressions of emotion (d = −0.58).

Conclusions/Significance

Results from the current analysis support the hypothesis that adults with anxiety disorders or major depression both have a deficit in recognizing facial expression of emotions, and that this deficit is more pronounced in major depression than in anxiety.     

Growth and substrate consumption of Nitrobacter agilis cells immobilized in carrageenan: part 2. Model evaluation

A dynamic model that predicts substrate and biomass concentration profiles across gel beads and from that the overall substrate consumption rate by the gel beads containing growing cells was evaluated with immobilized Nitrobacter agilis cells in an airlift loop reactor with oxygen as the limiting substrate. The model predictions agreed well with the observed oxygen consumption rates at three different liquid phase oxygen concentrations. Image analysis showed that 90% of the immobilized cells after 42 days of cultivation was situated in the outer shells in a film of 140 mum, while the bead radius was about 1 mm. The maximum biomass concentration in the outmost film of 56 mum was 11 kg . m(-3) gel.     

Rift Valley Fever Vaccine Virus Clone 13 Is Able to Cross the Ovine Placental Barrier Associated with Foetal Infections,Malformations, and Stillbirths

Rift Valley fever virus (RVFV) is a mosquito-borne pathogen that affects domesticated ruminants and occasionally humans. Classical RVF vaccines are based on formalin-inactivated virus or the live-attenuated Smithburn strain. The inactivated vaccine is highly safe but requires multiple administrations and yearly re-vaccinations. Although the Smithburn vaccine provides solid protection after a single vaccination, this vaccine is not safe for pregnant animals. An alternative live-attenuated vaccine, named Clone 13, carries a large natural deletion in the NSs gene which encodes the major virulence factor of the virus. The Clone 13 vaccine was previously shown to be safe for young lambs and calves. Moreover, a study in pregnant ewes suggested that the vaccine could also be applied safely during gestation. To anticipate on a possible future incursion of RVFV in Europe, we have evaluated the safety of Clone 13 for young lambs and pregnant ewes. In line with the guidelines from the World Organisation for Animal health (Office International des Epizooties, OIE) and regulations of the European Pharmacopeia (EP), these studies were performed with an overdose. Our studies with lambs showed that Clone 13 dissemination within vaccinated animals is very limited. Moreover, the Clone 13 vaccine virus was not shed nor spread to in-contact sentinels and did not revert to virulence upon animal-to-animal passage. Importantly, a large experiment with pregnant ewes demonstrated that the Clone 13 virus is able to spread to the fetus, resulting in malformations and stillbirths. Altogether, our results suggest that Clone 13 can be applied safely in lambs, but that caution should be taken when Clone 13 is used in pregnant animals, particularly during the first trimester of gestation.     

Immunogenicity and structural characterisation of an in vitro folded meningococcal siderophore receptor (FrpB, FetA)

The iron-limitation-inducible protein FrpB of Neisseria meningitidis is an outer-membrane-localized siderophore receptor. Because of its abundance and its capacity to elicit bactericidal antibodies, it is considered a vaccine candidate. Bactericidal antibodies against FrpB are, however, type-specific. Hence, an FrpB-based vaccine should comprise several FrpB variants to be capable of providing broad protection. To facilitate the development of a meningococcal subunit vaccine, we have established a procedure to obtain large quantities of the protein in a native-like conformation. The protein was expressed without its signal sequence in Escherichia coli, where it accumulated in inclusion bodies. After in vitro folding, the protein was biochemically, biophysically and biologically characterised. Our results show that in vitro folded FrpB assembles into oligomers, presumably dimers, and that it induces high levels of bactericidal antibodies in laboratory animals.     

Development of an inexpensive, low attenuation styrofoam primate chair for use in a PET scanner

Pharmacokinetic modelling of radiotracers for positron emission tomography (PET) imaging of neuroreceptors can be performed with time-activity data for brain and blood. We aimed to develop an alternative to withdrawal of arterial blood samples for acquisition of a blood curve. A supportive primate chair was constructed out of styrofoam and fixed to the head portion of the bed of a PET scanner. A lightly anaesthetised rhesus monkey was positioned in the chair in a sitting position and injected with the radiotracer. The styrofoam chair provided sufficient support for the monkey. The presence of the chair in the PET scanner caused negligible attenuation of radiation, allowing simultaneous acquisition of dynamic data from the subject's brain and heart. We conclude that a styrofoam primate chair is an ideal tool to measure blood and brain data from a rhesus monkey with PET. Invasiveness to the animal is reduced, as well as experimenter time.