Is metabolic activity by biofilms with sulfate-reducing bacterial consortia essential for long-term propagation of pitting corrosion of stainless steel?

Concentric electrodes have been fabricated from 304 stainless steel in which a small anode (0.031 cm²) and large cathode (4.87 cm²) are induced by the application of a current density of 11A cm^–2 at the anode. It has previously been shown that reproducible pitting and maintenance of a galvanic current occurs only in the presence of a consortium of bacteria containing sulphate-reducing bacteria (SRB). Actively corroding systems that had maintained a galvanic current for at least 24 h after the applied current was removed were treated with inhibitors of the SRB. The only inhibitor tested which had any marked effect on the galvanic current was sodium molybdate which is a known inhibitor of corrosion as well as SRB.     

Birds and biogeography of Mount Mecula in Mozambique’s Niassa National Reserve

The montane forests of northern Mozambique’s isolated massifs are inhabited by numerous range-restricted and threatened bird species, but until recently were extremely little-known. We report on a first avifaunal survey of the isolated montane habitats of Mt Mecula (1 442 m), Niassa National Reserve, notable as the only currently protected montane area in northern Mozambique. Mount Mecula’s moist forest is small (approximately 136 ha in total) and patchy, and although known botanically to have some montane affinities, was found to support an avifauna more typical of riparian forests of medium to low altitude. The only montane forest species recorded was Lemon Dove Aplopelia larvata. Other montane elements included Vincent’s Bunting Emberiza (capensis) vincenti, one of six species recorded new to the Niassa National Reserve list. Overall, it appears that despite its intermediate location, Mt Mecula does not represent a biogeographical ‘stepping stone’ for montane forest bird species. This probably owes to its remoteness from the Eastern Arc Mountains of Tanzania to the north and the massifs of other parts of northern Mozambique, to the south and west.     

Extreme cutaneous histamine sensitivity with hay fever and increased IgE concentrations in an unselected population.

Cutaneous sensitivity to histamine, responses to prick tests with allergens, and serum IgE concentrations were measured and hay fever assessed by questionnaire in an unselected population to determine whether increased sensitivity to histamine is an independent phenomenon contributing to allergic disorders or may be caused by allergic reactions. Increased cutaneous sensitivity to histamine was strongly associated with an increased number of positive responses to prick tests, high serum concentrations of IgE, and hay fever. This new test is simple, cheap, applicable to schoolchildren, and provides useful information.     

Molecular mechanism of the E99K mutation in cardiac actin (ACTC Gene) that causes apical hypertrophy in man and mouse

We generated a transgenic mouse model expressing the apical hypertrophic cardiomyopathy-causing mutation ACTC E99K at 50% of total heart actin and compared it with actin from patients carrying the same mutation. The actin mutation caused a higher Ca(2+) sensitivity in reconstituted thin filaments measured by in vitro motility assay (2.3-fold for mice and 1.3-fold for humans) and in skinned papillary muscle. The mutation also abolished the change in Ca(2+) sensitivity normally linked to troponin I phosphorylation. MyBP-C and troponin I phosphorylation levels were the same as controls in transgenic mice and human carrier heart samples. ACTC E99K mice exhibited a high death rate between 28 and 45 days (48% females and 22% males). At 21 weeks, the hearts of the male survivors had enlarged atria, increased interstitial fibrosis, and sarcomere disarray. MRI showed hypertrophy, predominantly at the apex of the heart. End-diastolic volume and end-diastolic pressure were increased, and relaxation rates were reduced compared with nontransgenic littermates. End-systolic pressures and volumes were unaltered. ECG abnormalities were present, and the contractile response to β-adrenergic stimulation was much reduced. Older mice (29-week-old females and 38-week-old males) developed dilated cardiomyopathy with increased end-systolic volume and continuing increased end-diastolic pressure and slower contraction and relaxation rates. ECG showed atrial flutter and frequent atrial ectopic beats at rest in some ACTC E99K mice. We propose that the ACTC E99K mutation causes higher myofibrillar Ca(2+) sensitivity that is responsible for the sudden cardiac death, apical hypertrophy, and subsequent development of heart failure in humans and mice.     

Molecular mechanisms of induction of antigen-specific allograft tolerance by intranasal peptide administration

We have previously shown that intranasal (i.n.) administration of a single MHC class II-restricted HY peptide to female mice induces tolerance to up to five additional epitopes expressed on test male grafts, a phenomenon known as linked suppression. In this study, we investigated the molecular mechanisms involved both in the induction phase following peptide administration and during linked suppression after grafting. We report that following initial i.n. administration, peptide is widely disseminated and is presented by functionally immature dendritic cells. These fail to cause optimal stimulation of the responding HY-specific CD4(+) T cells that express genes characteristic of regulatory T cells. Following i.n. peptide plus LPS administration, causing immunization, HY-specific CD4(+) T cells express genes characteristic of activated T cells. We further find that following male skin grafting, HY-specific CD8(+) T cells from peptide-treated tolerant mice display both quantitative and qualitative differences compared with similar cells from untreated mice that reject their grafts. In tolerant mice there are fewer HY-specific CD8(+) cells and they express several genes characteristic of exhausted T cells. Furthermore, associated with specific chemokine receptor and integrin expression, HY-specific CD8(+) T cells show more limited migration from the graft draining lymph node into other tissues.     

Crystal Structure of Patatin-17 in Complex with Aged and Non-Aged Organophosphorus Compounds

Patatin is a non-specific plant lipase and the eponymous member of a broad class of serine hydrolases termed the patatin-like phospholipase domain containing proteins (PNPLAs). Certain PNPLA family members can be inhibited by organophosphorus (OP) compounds. Currently, no structural data are available on the modes of interaction between the PNPLAs and OP compounds or their native substrates. To this end, we present the crystal structure of patatin-17 (pat17) in its native state as well as following inhibition with methyl arachidonyl fluorophosphonate (MAFP) and inhibition/aging with diisopropylphosphorofluoridate (DFP). The native pat17 structure revealed the existence of two portals (portal1 and portal2) that lead to its active-site chamber. The DFP-inhibited enzyme underwent the aging process with the negatively charged phosphoryl oxygen, resulting from the loss of an isopropyl group, being within hydrogen-binding distance to the oxyanion hole. The MAFP-inhibited pat17 structure showed that MAFP did not age following its interaction with the nucleophilic serine residue (Ser77) of pat17 since its O-methyl group was intact. The MAFP moiety is oriented with its phosphoryl oxygen in close proximity to the oxyanion hole of pat17 and its O-methyl group located farther away from the oxyanion hole of pat17 relative to the DFP-bound state. The orientation of the alkoxy oxygens within the two OP compounds suggests a role for the oxyanion hole in stabilizing the emerging negative charge on the oxygen during the aging reaction. The arachidonic acid side chain of MAFP could be contained within portals 1 or 2. Comparisons of pat17 in the native, inhibited, and aged states showed no significant global conformational changes with respect to their Cα backbones, consistent with observations from other α/β hydrolases such as group VIIA phospholipase A2.     

A novel approach to achieving modular retrovirus clearance for a parvovirus filter

Viral filtration is routinely incorporated into the downstream purification processes for the production of biologics produced in mammalian cell cultures (MCC) to remove potential viral contaminants. In recent years, the use of retentive filters designed for retaining parvovirus (～20 nm) has become an industry standard in a conscious effort to further improve product safety. Since retentive filters remove viruses primarily by the size exclusion mechanism, it is expected that filters designed for parvovirus removal can effectively clear larger viruses such as retroviruses (～100 nm). In an attempt to reduce the number of viral clearance studies, we have taken a novel approach to demonstrate the feasibility of claiming modular retrovirus clearance for Asahi Planova 20N filters. Porcine parvovirus (PPV) and xenotropic murine leukemia virus (XMuLV) were co‐spiked into six different feedstreams and then subjected to laboratory scale Planova 20N filtration. Our results indicate that Planova 20N filters consistently retain retroviruses and no retrovirus has ever been detected in the filtrates even when significant PPV breakthrough is observed. Based on the data from multiple in‐house viral validation studies and the results from the co‐spiking experiments, we have successfully claimed a modular retrovirus clearance of greater than 6 log₁₀ reduction factors (LRF) to support clinical trial applications in both USA and Europe. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 30:79–85, 2014     

Hydroxychloroquine Protects against Cardiac Ischaemia/Reperfusion Injury In Vivo via Enhancement of ERK1/2 Phosphorylation

An increasing number of investigations including human studies demonstrate that pharmacological ischaemic preconditioning is a viable way to protect the heart from myocardial ischaemia/reperfusion (I/R) injury. This study investigated the role of hydroxychloroquine (HCQ) in the heart during I/R injury. In vitro and in vivo models of myocardial I/R injury were used to assess the effects of HCQ. It was found that HCQ was protective in neonatal rat cardiomyocytes through inhibition of apoptosis, measured by TUNEL and cleaved caspase-3. This protection in vitro was mediated through enhancement of ERK1/2 phosphorylation mediated by HCQ in a dose-dependent fashion. A decrease in infarct size was observed in an in vivo model of myocardial I/R injury in HCQ treated animals and furthermore this protection was blocked in the presence of the ERK1/2 inhibitor U0126. For the first time, we have shown that HCQ promotes a preconditioning like protection in an in vivo simulated rat myocardial I/R injury model. Moreover, it was shown that HCQ is protective via enhanced phosphorylation of the pro-survival kinase ERK1/2.