Epichloë fungal endophyte interactions in perennial ryegrass (Lolium perenne L.) modified to accumulate foliar lipids for increased energy density.

BACKGROUND: Commercial cultivars of perennial ryegrass infected with selected Epichloë fungal endophytes are highly desirable in certain pastures as the resulting mutualistic association has the capacity to confer agronomic benefits (such as invertebrate pest deterrence) largely due to fungal produced secondary metabolites (e.g., alkaloids). In this study, we investigated T2 segregating populations derived from two independent transformation events expressing diacylglycerol acyltransferase (DGAT) and cysteine oleosin (CO) genes designed to increase foliar lipid and biomass accumulation. These populations were either infected with Epichloë festucae var. lolii strain AR1 or Epichloë sp. LpTG-3 strain AR37 to examine relationships between the introduced trait and the endophytic association. Here we report on experiments designed to investigate if expression of the DGAT + CO trait in foliar tissues of perennial ryegrass could negatively impact the grass-endophyte association and vice versa. Both endophyte and plant characters were measured under controlled environment and field conditions. RESULTS: Expected relative increases in total fatty acids of 17-58% accrued as a result of DGAT + CO expression with no significant difference between the endophyte-infected and non-infected progeny. Hyphal growth in association with DGAT + CO expression appeared normal when compared to control plants in a growth chamber. There was no significant difference in mycelial biomass for both strains AR1 and AR37, however, Epichloë-derived alkaloid concentrations were significantly lower on some occasions in the DGAT + CO plants compared to the corresponding null-segregant progenies, although these remained within the reported range for bioactivity. CONCLUSIONS: These results suggest that the mutualistic association formed between perennial ryegrass and selected Epichloë strains does not influence expression of the host DGAT + CO technology, but that endophyte performance may be reduced under some circumstances. Further investigation will now be required to determine the preferred genetic backgrounds for introgression of the DGAT + CO trait in combination with selected endophyte strains, as grass host genetics is a major determinant to the success of the grass-endophyte association in this species.

Linezolid-induced pancytopenia.

Linezolid is a bacteriostatic antibiotic of the Oxazolidinone class; it works by inhibiting the initiation of protein synthesis on bacterial ribosomes. Due to its excellent bioavailability after oral dosing, it has become an important tool in combating multi-drug-resistant bacteria including glycopeptide-resistant enterococci and methicillin-resistant Staphylococcus aureus Side effects are multiple and potentially serious. We report the case of an 87-year-old man who developed pancytopenia secondary to a 6-week course of linezolid. Withdrawal of the antibiotic was decided as the treatment and resolution of the pancytopenia was evident within 2 weeks. Clinicians should be aware of this side effect of linezolid therapy and that weekly full blood count monitoring is paramount.

Buttonhole needling of ateriovenous fistulae: a randomized controlled trial.

Buttonhole needling of arteriovenous fistulae (AVFs) was first described 30 years ago, but little evidence has been reported to show how it might differ from the standard rope-ladder technique. We carried out a randomized control trial comparing these two techniques. All suitable patients within the region were considered for recruitment. Patients were then randomized to continue with traditional rope-ladder needling or changed to buttonhole needling. A mean of 13.7 (median, 11) sharp needles were required to create a track. Nine of 22 patients in the buttonhole group reduced or stopped local anesthetic (LA) for needle insertion compared with one of 25 in the traditional group. The diameter of the buttonhole AVFs remained unchanged, whereas the control group increased in size by 30% +/- 7% (p < 0.01), equivalent to an absolute increase of 5 mm. There was no difference in bleeding times, but there was a preference for the buttonhole technique with 21 of the 22 patients and 15 of 23 nurses preferring buttonhole needling. Buttonhole needling is preferred by both patients and staff, reduces discomfort during needling and reduces AVF enlargement. There is a low level of complication.

Generalized hyperpigmentation with daunorubicin chemotherapy.

Daunorubicin has been reported to cause hyperpigmentation of sun-exposed skin and/or transverse nail pigmentation (3 cases). We report a case of an African American man who had an atypical pattern of generalized hyperpigmentation develop that involved many sun-protected skin areas 2 weeks after daunorubicin treatment. Histopathology of hyperpigmented skin showed increased melanin granules in all epidermal layers. The mechanisms by which daunorubicin may increase skin pigmentation are discussed.