The mitochondrial genome contribution to the phylogeny and identification of Metarhizium species and strains.

The genus Metarhizium is composed of entomopathogenic fungal biological control agents (BCAs) used for invertebrate pest control. The phylogenetic relationships of species within this genus are still under scrutiny as several cryptic species can be found. In this work, the mitochondrial (mt) genome of Metarhizium brunneum ARSEF 4556 was fully sequenced and a comparative genome analysis was conducted with 7 other available mt genomes, belonging to 5 Metarhizium species: M. anisopliae, M. brunneum, M. robertsii, M. guizhouense and M. majus. Results showed that Metarhizium demonstrates greater conserved stability than other fungal mt genomes. Furthermore, this analysis located 7 diverse regions in both intergenic domains and gene fragments which were ideal for species/strain discrimination. The sequencing of these regions revealed several SNPs among 38 strains tested, 11 of which were uncharacterized. Single gene phylogenies presented variable results which may be used further for intra-species discrimination. Phylogenetic trees based on the concatenation of mt domains and the nuclear ITS1-5.8S-ITS2 region showed discrimination of the species studied and allowed the identification of uncharacterized strains. These were mostly placed within species M. anisopliae and M. brunneum. Five strains clustered together in a clade related to M. brunneum, suggesting that they comprise a cryptic species.

FISHing in fungi: Visualisation of mushroom virus X in the mycelium of Agaricus bisporus by fluorescence in situ hybridisation.

Agaricus bisporus is a commercial mushroom crop susceptible to a disease caused by a complex of viruses known collectively as mushroom virus X (MVX). Symptoms of MVX include bare patches and mushroom cap discolouration (browning) in the fruiting bodies, phenotypes associated with the viruses AbV6 and AbV16, respectively. Limited understanding exists of the localisation and mobilisation of these viruses within the mycelium of A. bisporus. To this end, a non-destructive fluorescence in situ hybridisation (FISH) method was developed for in situ targeting of AbV6 and AbV16 in A. bisporus mycelium. An MVX strain associated with the bare patch disease phenotype revealed predominantly high signal towards the growing edges of cultures when probed for AbV6, with a 'halo-effect' of high signal intensity around putative vacuoles. An MVX strain associated with the browning disease phenotype showed high signal intensities within reticulating networks of hyphae in a highly compartmentalised manner when probed for AbV16. Localisation of the two viruses in MVX-infected cultures appears independent, as both viruses were found in completely discrete areas of the mycelium in differential patterns. FISH detected low level presence of the two viruses, AbV6 and AbV16 in a number of cultures which had tested negative for the viruses by RT-PCR. This suggests that FISH may be more sensitive at detecting viruses at low levels than molecular methods. This study demonstrates that FISH is a powerful tool in the field of mycovirology.

Factors that influence parathyroid hormone half-life: determining if new intraoperative criteria are needed.

IMPORTANCE: Minimally invasive parathyroidectomy using intraoperative parathyroid hormone monitoring remains the standard approach to the majority of patients with primary hyperparathyroidism. This study demonstrates that individual patient characteristics do not affect existing criteria for intraoperative parathyroid hormone monitoring. OBJECTIVE: To identify patient characteristics, such as age, sex, race, body mass index (BMI), and renal function, that may affect existing criteria for intraoperative parathyroid hormone (IOPTH) levels during minimally invasive parathyroidectomy. DESIGN: Retrospective review of a prospectively collected parathyroid database populated from August 2005 to April 2011. SETTING: Academic medical center. PARTICIPANTS: Three hundred six patients with sporadic primary hyperparathyroidism who underwent initial parathyroidectomy between August 2005 and April 2011. INTERVENTIONS: All patients underwent minimally invasive parathyroidectomy with complete IOPTH information. MAIN OUTCOME AND MEASURES: Individual IOPTH kinetic profiles were fitted with an exponential decay curve and individual IOPTH half-lives were determined. Univariate and multivariate analyses were performed to determine the association between patient demographics or laboratory data and IOPTH half-life. RESULTS: Mean age of the cohort was 60 years, 78.4% were female, 90.2% were white, and median BMI was 28.3. Overall, median IOPTH half-life was 3 minutes, 9 seconds. On univariate analysis, there was no association between IOPTH half-life and patient age, renal function, or preoperative serum calcium or parathyroid hormone levels. Age, BMI, and an age × BMI interaction were included in the final multivariate median regression analysis; race, sex, and glomerular filtration rate were not predictors of IOPTH half-life. The IOPTH half-life increased with increasing BMI, an effect that diminished with increasing age and was negligible after age 55 years (P = .001). CONCLUSIONS AND RELEVANCE: Body mass index, especially in younger patients, may have a role in the IOPTH half-life of patients undergoing parathyroidectomy. However, the differences in half-life are relatively small and the clinical implications are likely not significant. Current IOPTH criteria can continue to be applied to all patients undergoing parathyroidectomy for sporadic primary hyperparathyroidism.

Changes in gene expression in Arabidopsis shoots during phosphate starvation and the potential for developing smart plants.

Our aim was to generate and prove the concept of "smart" plants to monitor plant phosphorus (P) status in Arabidopsis. Smart plants can be genetically engineered by transformation with a construct containing the promoter of a gene up-regulated specifically by P starvation in an accessible tissue upstream of a marker gene such as beta-glucuronidase (GUS). First, using microarrays, we identified genes whose expression changed more than 2.5-fold in shoots of plants growing hydroponically when P, but not N or K, was withheld from the nutrient solution. The transient changes in gene expression occurring immediately (4 h) after P withdrawal were highly variable, and many nonspecific, shock-induced genes were up-regulated during this period. However, two common putative cis-regulatory elements (a PHO-like element and a TATA box-like element) were present significantly more often in the promoters of genes whose expression increased 4 h after the withdrawal of P compared with their general occurrence in the promoters of all genes represented on the microarray. Surprisingly, the expression of only four genes differed between shoots of P-starved and -replete plants 28 h after P was withdrawn. This lull in differential gene expression preceded the differential expression of a new group of 61 genes 100 h after withdrawing P. A literature survey indicated that the expression of many of these "late" genes responded specifically to P starvation. Shoots had reduced P after 100 h, but growth was unaffected. The expression of SQD1, a gene involved in the synthesis of sulfolipids, responded specifically to P starvation and was increased 100 h after withdrawing P. Leaves of Arabidopsis bearing a SQD1::GUS construct showed increased GUS activity after P withdrawal, which was detectable before P starvation limited growth. Hence, smart plants can monitor plant P status. Transferring this technology to crops would allow precision management of P fertilization, thereby maintaining yields while reducing costs, conserving natural resources, and preventing pollution.