Genetic relatedness of Legionella longbeachae isolates from human and environmental sources in Australia.

The genetic relatedness of Legionella longbeachae isolated in Australia since 1987 was investigated by restriction fragment length polymorphism (RFLP) analysis and allozyme electrophoresis. Three radiolabeled probes were used in Southern hybridizations for the RFLP studies. They were Escherichia coli 16S and 23S rRNA and cloned fragments of L. longbeachae selected empirically from genomal banks in lambda and a cosmid. The legionellae included in the study comprised 11 Legionella longbeachae serogroup 1 organisms isolated from humans, 28 L. longbeachae serogroup 1 isolates from environmental sources, and 3 L. longbeachae serogroup 2 environmental isolates. These were compared with the American Type Culture Collection reference strains of both serogroups and some other related Legionella species. Results of allozyme and RFLP analysis showed that all the isolates from humans and all but three of the environmental L. longbeachae serogroup 1 isolates were closely related. They were also closely related to L. longbeachae serogroup 1 ATCC 33462. There was wider variation among the three L. longbeachae serogroup 2 environmental isolates. One of these was closely related to L. longbeachae serogroup 2 ATCC 33484. RFLP studies with the rRNA probe provided the most discrimination among isolates but did not distinguish between the two serogroups.     

Genetic transformation of grapevine cells

Biovar 1 strains ofAgrobacterium tumefaciens have been used to transform a cell suspension culture ofVitis vinifera cv. Cabernet Sauvignon. Cocultivation of cultures withAgrobacterium strains bearing either the cointegrate pGV3850::1103neo, or the binary vector pGA474-68, each gave rise to kanamycin resistant tissue. The stable integration and expression of the neomycin phosphotransferase gene was confirmed by Southern blotting and enzymic assay, respectively.Abbreviations NPTII neomycin phosphotransferase II - NOS nopaline synthase - FSAC fragmented shoot apex culture - TES N-tris-(hydroxymethyl)methyl-2-aminoethane sulfonic acid     

High-resolution profiles of temperature and dissolved oxygen in a river

Longitudinal profiles of water quality along a well-mixed tidal river are, ideally, based on simultaneous measurements at fixed stations distributed along the river. The resolution of the profiles is limited by the density of the stations. However, for a given number of stations the resolution is greatly increased if water quality date can be extrapolated upstream and downstream of the stations, making use of velocity data; the resolution is then determined by the density of the extrapolated data points, which may be an order of magnitude higher than the density of the stations. A 15-km length of river was investigated using 5 current meters equipped to measure depth, temperature, conductivity and dissolved oxygen. Data were recorded simultaneously every 10 minutes. When the average cross-sectional speed was 0.25 ms⁻¹ (typical of tidal conditions), the extrapolated data points were 150 m apart, so the resolution of the resulting profiles (7 per kilometre) was much higher than that of the stations alone (0.3 per kilometre). The extrapolation process required a means of deducing the average cross-sectional speed from the speed measured at a given station. The key to this was provided by temperature data recorded during the onset of a spate, when tidal flow was suspended and the average cross-sectional speed was uniformly about 0.75 ms ⁻¹ at four of the stations. Profiles of temperature and dissolved oxygen were generated by this method; the resolution was about 2 data points km⁻¹ during the onset of the spate, and 6 points km⁻¹ during tidal flow.     

Clinical and behavioural risk indicators for root caries in older people

Objective: To investigate the clinical and behavioural factors indicating root caries risk among older people. Desing: Cross sectional clinical and interview data from the National Diet and Nutrition Survey (aged 65 years and over) in Great Britain. Logistic regression models of the prevalence of root caries and linear regression models of the extent of root caries were constructed to quantify the role of a range of clinical and behavioural risk indicators, including sugars intake. Setting: A national sample of older British adults, free‐living and institutionalised. Participants: 462 dentate adults aged 65 years or over. Results: Nine or more intakes of sugars per day more than doubled the odds of root caries being present (OR 2.2–2.4). Other clinical and behavioural factors affecting root caries included wearing a partial denture in the presence of heavy plaque deposits (OR 2.1–2.6) and infrequent tooth brushing (OR 2.8 – 4.1). Linear regression models showed that, amongst those that had root caries, sucking sweets in the presence of a dry mouth, poor hygiene, partial dentures and living in an institution contributed to the extent of root caries, as measured by the RCI(d). Conclusions: Of the factors open to possible clinical or behavioural intervention, frequent sugars intake, poor hygiene and partial dentures were all associated with large increases in risk.     

Reovirus activates human dendritic cells to promote innate antitumor immunity

Oncolytic viruses can exert their antitumor activity via direct oncolysis or activation of antitumor immunity. Although reovirus is currently under clinical investigation for the treatment of localized or disseminated cancer, any potential immune contribution to its efficacy has not been addressed. This is the first study to investigate the ability of reovirus to activate human dendritic cells (DC), key regulators of both innate and adaptive immune responses. Reovirus induced DC maturation and stimulated the production of the proinflammatory cytokines IFN-alpha, TNF-alpha, IL-12p70, and IL-6. Activation of DC by reovirus was not dependent on viral replication, while cytokine production (but not phenotypic maturation) was inhibited by blockade of PKR and NF-kappaB signaling. Upon coculture with autologous NK cells, reovirus-activated DC up-regulated IFN-gamma production and increased NK cytolytic activity. Moreover, short-term coculture of reovirus-activated DC with autologous T cells also enhanced T cell cytokine secretion (IL-2 and IFN-gamma) and induced non-Ag restricted tumor cell killing. These data demonstrate for the first time that reovirus directly activates human DC and that reovirus-activated DC stimulate innate killing by not only NK cells, but also T cells, suggesting a novel potential role for T cells in oncolytic virus-induced local tumor cell death. Hence reovirus recognition by DC may trigger innate effector mechanisms to complement the virus's direct cytotoxicity, potentially enhancing the efficacy of reovirus as a therapeutic agent.     

Harmonic oscillators: the quantization of simple systems in the old quantum theory and their functional roles in biology

This article introduces quantum physics into biology in an intuitive and non-intimidating manner. It extends the quantum aspects of harmonic oscillators, and electromagnetic fields, to their functional roles in biology. Central to this process are the De Broglie wave-particle duality equation, and the adiabatic invariant parameters, magnetic moment, angular momentum and magnetic flux, determined by Ehrenfest as imposing quantum constraints on the dynamics of charges in motion. In mechanisms designed to explain the generation of low-level light emissions in biology we have adopted a biological analog of the electrical circuitry modeled on the parallel plated capacitor, traversed by helical protein structures, capable of generating electromagnetic radiation in the optical spectral region. The charge carrier required for the emissions is an accelerating electron driven, in a cyclotron-type mechanism, by ATP-induced reverse electron transfer with the radial, emission, components, mediated by coulombic forces within the helical configurations. Adenine, an essential nucleotide constituent of DNA, was examined with its long wavelength absorption maximum determining the energetic parameters for the calculations. The calculations were made for a virtual 5-turn helix where each turn of the helix emits a different frequency, generating a biological quantum series. The components of six adiabatic invariant equations were found to be embedded in Planck's constant rendering them discrete, finite, non-random, non-statistical-Planck's constant precludes probability. A mechanism for drug-induced hallucination is described that might provide insights as to the possible role of electromagnetic fields in consciousness. Sodium acceleration through a proposed nerve membrane helical channel generated electromagnetic emissions in the microwave region in confirmation of reported microwave emission for active nerves and may explain saltatory nerve conduction. Theoretical calculations for a helical DNA system gave a conduction resistance in agreement with a experimentally determined parameter.     

Analysis of transcriptional profiles and functional clustering of global cerebellar gene expression in PCD3J mice

The Purkinje cell degeneration (PCD) mutant mouse is characterized by a degeneration of cerebellar Purkinje cells and progressive ataxia. To identify the molecular mechanisms that lead to the death of Purkinje neurons in PCD mice, we used Affymetrix microarray technology to compare cerebellar gene expression profiles in pcd3J mutant mice 14 days of age (prior to Purkinje cell loss) to unaffected littermates. Microarray analysis, Ingenuity Pathway Analysis (IPA) and expression analysis systematic explorer (EASE) software were used to identify biological and molecular pathways implicated in the progression of Purkinje cell degeneration. IPA analysis indicated that mutant pcd3J mice showed dysregulation of specific processes that may lead to Purkinje cell death, including several molecules known to control neuronal apoptosis such as Bad, CDK5 and PTEN. These findings demonstrate the usefulness of these powerful microarray analysis tools and have important implications for understanding the mechanisms of selective neuronal death and for developing therapeutic strategies to treat neurodegenerative disorders.     

The 67 kDa laminin receptor: structure, function and role in disease

The 67LR (67 kDa laminin receptor) is a cell-surface receptor with high affinity for its primary ligand. Its role as a laminin receptor makes it an important molecule both in cell adhesion to the basement membrane and in signalling transduction following this binding event. The protein also plays critical roles in the metastasis of tumour cells. Isolation of the protein from either normal or cancerous cells results in a product with an approx. molecular mass of 67 kDa. This protein is believed to be derived from a smaller precursor, the 37LRP (37 kDa laminin receptor precursor). However, the precise mechanism by which cytoplasmic 37LRP becomes cell-membrane-embedded 67LR is unclear. The process may involve post-translational fatty acylation of the protein combined with either homo- or hetero-dimerization, possibly with a galectin-3-epitope-containing partner. Furthermore, it has become clear that acting as a receptor for laminin is not the only function of this protein. 67LR also acts as a receptor for viruses, such as Sindbis virus and dengue virus, and is involved with internalization of the prion protein. Interestingly, unmodified 37LRP is a ribosomal component and homologues of this protein are found in all five kingdoms. In addition, it appears to be strongly associated with histones in the eukaryotic cell nucleus, although the precise role of these interactions is not clear. Here we review the current understanding of the structure and function of this molecule, as well as highlighting areas requiring further research.     

Carbohydrate and lipid metabolism in cockroach (Periplaneta americana) fat body are both activated by low and similar concentrations of Peram-AKH II

Injection of 0.1 pmol of the octapeptide Peram-AKH II (pGlu-Leu-Thr-Phe-Thr-Pro-Asn-TrpNH(2)) elicits a significant hypertrehalosemic response in the American cockroach, Periplaneta americana; a maximal effect is obtained with 1pmol. The latter amount also lowers the level of neutral lipid (NL) and phospholipid (PL) in the hemolymph. The evidence supports the idea that Peram-AKH II promotes the liberation of fatty acids from hemolymph phospholipid, and indirectly diacylglycerol in the same compartment. The fatty acids are then transported into the fat body where they are converted into triacylglycerol for storge. Because lipolysis and trehalose synthesis are initiated by a common concentration of Peram-AKH II it is reasonable to suggest that the physiological function of Peram-AKH II involves the participation of both metabolic pathways.