Puccinia pelargonii-zonalis (Uredinales: Pucciniaceae), an addition to the rust flora of Canada

Puccinia pelargonii-zonalis is reported for the first time in Canada. It has occurred on cultivated geraniums (Pelargonium × hortorum) in both greenhouses and gardens in three provinces.     

Surface interactions between mammalian sperm and egg: variation of spermatozoa concentration as a probe for the study of binding in vitro.

The pre-penetration binding interactions between gametes of the golden hamster were investigated in vitro. Binding between capacitated spermatozoa and the surface of eggs, that is the zonae pellucidae with intact vitelli, as a function of the concentration of spermatozoa, followed a sigmoidal curve. This was in sharp contrast to the linear binding obtained with mechanically isolated zonae pellucidae (zonae lacking vitelli). Penetration of eggs as a function of the concentration of spermatozoa paralleled the binding curve that occurred between gametes. The binding curve obtained with uncapacitated spermatozoa and eggs was not sigmoidal but was linear after a slight lag and parallel to the curve obtained with uncapacitated spermatozoa and isolated zonae pellucidae. Taken together these results support previous work which implicated a vitelline factor in the binding reaction between the surfaces of eggs and capacitated spermatozoa. By scoring binding at one minute intervals it was possible to relate the rapid uninterrupted binding that occurs between capacitated spermatozoa and isolated zonae pellucidae with the equally rapid but transient and vitellus-influenced binding that occurs between gametes. It was concluded that the vitelline factor acts by preventing most of the early type of binding that occurs between spermatozoa and isolated zonae pellucidae and not by terminating the early, rapid, initial binding as previously postulated. Thus, this early binding never occurs between most of the gametes that finally bind 30 to 40 minutes later and, therefore, does not play a role in the establishment of the late binding step which leads to penetration.     

Justice and Surgical Innovation: The Case of Robotic Prostatectomy

Surgical innovation promises improvements in healthcare, but it also raises ethical issues including risks of harm to patients, conflicts of interest and increased injustice in access to health care. In this article, we focus on risks of injustice, and use a case study of robotic prostatectomy to identify features of surgical innovation that risk introducing or exacerbating injustices. Interpreting justice as encompassing matters of both efficiency and equity, we first examine questions relating to government decisions about whether to publicly fund access to innovative treatments. Here the case of robotic prostatectomy exemplifies the difficulty of accommodating healthcare priorities such as improving the health of marginalized groups. It also illustrates challenges with estimating the likely long‐term costs and benefits of a new intervention, the difficulty of comparing outcomes of an innovative treatment to those of established treatments, and the further complexity associated with patient and surgeon preferences. Once the decision has been made to fund a new procedure, separate issues of justice arise at the level of providing care to individual patients. Here, the case of robotic prostatectomy exemplifies how features of surgical innovation, such as surgeon learning curves and the need for an adequate volume of cases at a treatment centre, can exacerbate injustices associated with treatment cost and the logistics of travelling for treatment. Drawing on our analysis, we conclude by making a number of recommendations for the just introduction of surgical innovations.     

Erythrophore cell response to food‐associated pathogenic bacteria: implications for detection

Cell‐based biosensors have been proposed for use as function‐based detectors of toxic agents. We report the use of Betta splendens chromatophore cells, specifically erythrophore cells, for detection of food‐associated pathogenic bacteria. Evaluation of erythrophore cell response, using Bacillus spp., has revealed that this response can distinguish pathogenic Bacillus cereus from a non‐pathogenic B. cereus ΔplcR deletion mutant and a non‐pathogenic Bacillus subtilis. Erythrophore cells were exposed to Salmonella enteritidis, Clostridium perfringens and Clostridium botulinum. Each bacterial pathogen elicited a response from erythrophore cells that was distinguished from the corresponding bacterial growth medium, and this observed response was unique for each bacterial pathogen. These findings suggest that erythrophore cell response has potential for use as a biosensor in the detection and toxicity assessment for food‐associated pathogenic bacteria.     

Structural determinants of a glucocorticoid receptor recognition element

Analysis of the relative inducibility of an extensive series of mutant glucocorticoid response elements (GREs) defines features critical to the constitution of an active GRE. Assuming that function as a GRE reflects binding of glucocorticoid receptor, our activity data are consistent with the recognition of the GRE as two hexamer half-sites, each half-site recognized by a single subunit of a receptor dimer, probably in a cooperative fashion. Integrity of both half-sites is necessary for an active element, and spacing of the half-sites is critical. The identity of 1 basepair within the hexamer half-site is unconstrained; the receptor probably makes no base-specific contacts at this position. In contrast, at other positions within the half-site, limited substitutions (if any) can be tolerated. These results along with data from certain insertion mutations suggest that the receptor recognizes each hexamer half-site as two separable subelements. A further implication is that the DNA-binding domain of the glucocorticoid receptor is composed of distinct subdomains, which interact with the subelements of the recognition sequence.