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Candida albicans biofilms are composed of highly adherent and densely arranged cells with properties distinct from those of free-floating (planktonic) cells. These biofilms are a significant medical problem because they commonly form on implanted medical devices, are drug resistant and are difficult to remove. C. albicans biofilms are not static structures; rather they are dynamic and develop over time. Here we characterize gene expression in biofilms during their development, and by comparing them to multiple planktonic reference states, we identify patterns of gene expression relevant to biofilm formation. In particular, we document time-dependent changes in genes involved in adhesion and metabolism, both of which are at the core of biofilm development. Additionally, we identify three new regulators of biofilm formation, Flo8, Gal4, and Rfx2, which play distinct roles during biofilm development over time. Flo8 is required for biofilm formation at all time points, and Gal4 and Rfx2 are needed for proper biofilm formation at intermediate time points., (© 2015 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)

The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the biofilm state, where tightly packed bacterial, archaeal, and fungal cells must cooperate and/or compete for resources in order to survive. We examined mixed biofilms composed of the major fungal species of the gut microbiome, Candida albicans, and each of five prevalent bacterial gastrointestinal inhabitants: Bacteroides fragilis, Clostridium perfringens, Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. We observed that biofilms formed by C. albicans provide a hypoxic microenvironment that supports the growth of two anaerobic bacteria, even when cultured in ambient oxic conditions that are normally toxic to the bacteria. We also found that coculture with bacteria in biofilms induces massive gene expression changes in C. albicans, including upregulation of WOR1, which encodes a transcription regulator that controls a phenotypic switch in C. albicans, from the "white" cell type to the "opaque" cell type. Finally, we observed that in suspension cultures, C. perfringens induces aggregation of C. albicans into "mini-biofilms," which allow C. perfringens cells to survive in a normally toxic environment. This work indicates that bacteria and C. albicans interactions modulate the local chemistry of their environment in multiple ways to create niches favorable to their growth and survival., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Unlabelled: Biofilms are resilient, surface-associated communities of cells with specialized properties (e.g., resistance to drugs and mechanical forces) that are distinct from those of suspension (planktonic) cultures. Biofilm formation by the opportunistic human fungal pathogen Candida albicans is medically relevant because C. albicans infections are highly correlated with implanted medical devices, which provide efficient substrates for biofilm formation; moreover, biofilms are inherently resistant to antifungal drugs. Biofilms are also important for C. albicans to colonize diverse niches of the human host. Here, we describe four core members of a conserved histone deacetylase complex in C. albicans (Set3, Hos2, Snt1, and Sif2) and explore the effects of their mutation on biofilm formation. We find that these histone deacetylase complex members are needed for proper biofilm formation, including dispersal of cells from biofilms and multifactorial drug resistance. Our results underscore the importance of the physical properties of biofilms in contributing to drug resistance and dispersal and lay a foundation for new strategies to target biofilm dispersal as a potential antifungal intervention., Importance: Through the formation of biofilms--surface-associated communities of cells--microorganisms can establish infections, become drug resistant, and evade the host immune system. Here we investigate how four core members of a conserved histone deacetylase complex mediate biofilm formation by Candida albicans, the major fungal pathogen of humans. We show that this histone deacetylase complex is required for biofilm dispersal, a process through which cells leave the biofilm to establish new infections. We also show that the deacetylase complex mediates biofilm drug resistance. This work provides new insight into how the physical properties of biofilms affect dispersal and drug resistance and suggests new potential antifungal strategies that could be effective against biofilms., (Copyright © 2014 Nobile et al.)

Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced - under a specialized set of conditions - to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such "pheromone-stimulated" biofilms with that of "conventional" C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 196 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former.

Candida albicans is a commensal microorganism of the human microbiome; it is also the most prevalent fungal pathogen of humans. Many infections caused by C. albicans are a direct consequence of its proclivity to form biofilms--resilient, surface-associated communities of cells where individual cells acquire specialized properties that are distinct from those observed in suspension cultures. We recently identified the transcriptional network that orchestrates the formation of biofilms in C. albicans. These results set the stage for understanding how biofilms are formed and, once formed, how the specialized properties of biofilms are elaborated. This information will provide new insight for understanding biofilms in more detail and may lead to improvements in preventing and treating biofilm-based infections in the future.

A biofilm is an organized, resilient group of microbes in which individual cells acquire properties, such as drug resistance, that are distinct from those observed in suspension cultures. Here, we describe and analyze the transcriptional network controlling biofilm formation in the pathogenic yeast Candida albicans, whose biofilms are a major source of medical device-associated infections. We have combined genetic screens, genome-wide approaches, and two in vivo animal models to describe a master circuit controlling biofilm formation, composed of six transcription regulators that form a tightly woven network with ∼1,000 target genes. Evolutionary analysis indicates that the biofilm network has rapidly evolved: genes in the biofilm circuit are significantly weighted toward genes that arose relatively recently with ancient genes being underrepresented. This circuit provides a framework for understanding many aspects of biofilm formation by C. albicans in a mammalian host. It also provides insights into how complex cell behaviors can arise from the evolution of transcription circuits., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Dapper was isolated in a screen for proteins interacting with Dishevelled, a key factor in Wnt signaling. Dapper and Dishevelled colocalize intracellularly and form a complex with Axin, GSK-3, CKI, and beta-catenin. Overexpression of Dapper increases Axin and GSK-3 in this complex, resulting in decreased soluble beta-catenin and decreased activation of beta-catenin-responsive genes. Dapper also inhibits activation by Dishevelled of c-Jun N-terminal kinase (JNK), a component of beta-catenin-independent Frizzled signaling. Inhibition of Dapper activates both beta-catenin-responsive genes and an AP1-responsive promoter, demonstrating that Dapper is a general Dishevelled antagonist. Depletion of maternal Dapper RNA from Xenopus embryos results in loss of notochord and head structures, demonstrating that Dapper is required for normal vertebrate development.

Transgene insertions in the mouse often cause mutations at chromosomal loci. Analysis of insertion mutations that cause male sterility may lead to the identification of novel molecular mechanisms implicated in male fertility. Here we show a line of transgenic mice with dominant inheritance of male sterility (DMS) that was found amid several lines that were normally fertile. Transgene-positive males from this line invariably were sterile, whereas transgenic females and transgene-negative male littermates were fertile. Histologic analysis and TUNEL staining for apoptotic cells in DMS testis showed spermatogenesis arrest at metaphase of meiosis I (M-I), accompanied by massive apoptosis of spermatocytes. Meiosis I arrest was incomplete, however, as small numbers of spermatids and spermatozoa were found. Both round spermatids and spermatozoa were evaluated for their permissiveness in the assisted reproductive technologies intracytoplasmic sperm injection (ICSI) and round spermatid injection (ROSI). Surprisingly, ROSI but not ICSI gave live offspring, suggesting that mature sperm had deteriorated by the time of recovery from the epididymis. Mapping the transgene insertion by fluorescence in situ hybridization revealed a site on chromosome 14 D3-E1. Two candidate genes, GFR alpha 2 and GnRH, that were previously mapped to that region and the functions of which in spermatogenesis are well established were not altered in DMS. As a consequence, positional cloning of the DMS locus will be essential to identify new molecules potentially involved in arrest at M-I. Furthermore, mice carrying this genetic trait might be useful for studies of assisted reproductive technologies and male contraceptives.

Purpose: We sought to determine the incidence of neutropenic fever associated with the use of standard-dose combination chemotherapy for small-cell lung cancer (SCLC) and to use these data as a template to analyze the costs and benefits of the routine use of granulocyte colony-stimulating factor (G-CSF)., Patients and Methods: We retrospectively reviewed records of 137 consecutive, unselected patients with SCLC treated with combination chemotherapy from January 1987 to March 1992. Admission criteria for neutropenic fever were temperature > or = 38.5 degrees C and an absolute neutrophil count < or = 500/microL. Neutropenic fevers were managed with a 25% dose reduction of the myelosuppressive drugs in subsequent cycles. Charge estimates for hospitalization ($1,244 per day) and G-CSF use ($2,027 per course) were estimated by reviewing charges to patients at Indiana University hospitalized for neutropenic fever or treated with outpatient G-CSF. We imposed assumptions from the Neupogen (filgrastim; Amgen Inc, Thousand Oaks, CA) licensing trial regarding the effectiveness of G-CSF and the Indiana University charge estimates on three models of G-CSF use: (1) preemptive--with all courses of chemotherapy, (2) reactive--with all cycles of chemotherapy following a neutropenic fever, and (3) dose reduction only (no G-CSF)--to derive charge estimates for G-CSF use., Results: Records of 137 patients with SCLC were identified and reviewed. The incidence of neutropenic fever was 12% in the first cycle of chemotherapy, and 18% overall, compared with the placebo- and G-CSF-treated arms of the Neupogen licensing trial, in which the incidence of neutropenic fever was 77% and 40%, respectively. Other therapeutic outcomes, such as neutropenic septic deaths, response rates, and survival, were comparable. We derived the following charge estimates for the three models of G-CSF: (1) preemptive--total charges = $1,287,481; (2) reactive--total charges = $276,154; and (3) dose reduction only--total charges = $192,820., Conclusion: The incidence of neutropenic fever with standard-dose chemotherapy for SCLC was 18%. Routine use of G-CSF in SCLC patients treated with standard-dose chemotherapy appears to be expensive and is not associated with an obvious therapeutic benefit or cost savings. We suggest that careful analysis of the incidence of infectious complications, rather than granulocyte nadir and duration, be performed, and that clinical guidelines for the use of these effective, but expensive, products be developed.

Surgery following chemotherapy for treatment of metastatic testis cancer is reserved for partial remissions with localized tumors considered resectable. After primary chemotherapy, about 90% will have teratoma or necrosis and only 10% will have cancer. The concept of two cycles of post operative chemotherapy in this small group with cancer is supported by a 70% long term cure rate. A more difficult group of patients are those who have had not only primary but also salvage chemotherapy for refractory tumor. About 55% of these patients undergoing post (salvage) chemotherapy RPLND surgery have persistent cancer in the resected specimen. There is no data to support the routine use of repeat salvage chemotherapy post operatively. Of 91 patients presenting for surgery post salvage chemotherapy, 53 were considered completely resected and 36 incompletely resected. Of the 53 realistic candidates for cure with complete resections, 25 were given post operative repeat salvage chemotherapy and 28 received none. 9 (36%) receiving more chemotherapy remained NED and 12 (43%) receiving none remained NED. 12 in each group died of disease. Therefore, there is no data to support routine repeat salvage chemotherapy in patients considered completely resected who had already received salvage chemotherapy pre-operatively. Rather the outcome in this cohort depends more on the completeness of its resectability.

Purpose: We review the long-term outcome of patients with viable nonteratomatous germ cell tumor (NTGCT) in retroperitoneal lymph node dissection (RPLND) specimens after primary or salvage chemotherapy, and the impact of postoperative therapy with two courses of standard-dose cisplatin-based induction chemotherapy., Patients and Methods: All patients with viable NTGCT in postchemotherapy RPLND specimens from surgeries performed at Indiana University between July 1975 and March 1991 were retrospectively reviewed., Results: Of 580 postchemotherapy RPLNDs performed, 133 had viable NTGCT in their pathology specimens. Of these 580 postchemotherapy RPLNDs, 417 were performed after primary chemotherapy, and 43 (10%) had viable NTGCT in their pathology specimens. There were 163 RPLNDs performed after salvage chemotherapy and 90 (55%) had viable NTGCT in their pathology specimens. After primary chemotherapy, 34 of 43 had complete resections, and 27 of the 34 received postoperative cisplatin-based chemotherapy. Nineteen of 27 (70%) are continuously disease-free (c-NED). All seven who received no postoperative chemotherapy have relapsed. After salvage chemotherapy, 53 of 90 had complete resections. Of those 53, 25 received postoperative chemotherapy, and nine (36%) are c-NED. Twenty-eight received no postoperative chemotherapy, and 12 (43%) are c-NED. Overall, 43 of 133 patients had incomplete resections, and only four are currently disease-free. There were four postoperative deaths (PODs)., Conclusion: (1) Incomplete resection of viable NTGCT after primary or salvage chemotherapy portends a very poor prognosis. (2) For patients with complete resection of viable NTGCT following primary chemotherapy, two additional courses of cisplatin-based chemotherapy appear to be safe and effective therapy for reducing the risk of relapse. (3) Additional standard-dose chemotherapy appears to offer no benefit to patients with viable NTGCT in the resected specimen after salvage chemotherapy.

This article presents a review of the spectrum of extragonadal germ cell tumors, a fascinating group of rare and biologically diverse tumors. Although like testicular germ cell tumors, these tumors are chemotherapeutically responsive, the overall prognosis is not as good. Pediatric germ cell tumors share many of the biologic characteristics of the adult tumors but are more likely to be benign. An unusual aspect of mediastinal germ cell tumors, in particular, is their association with nontreatment-related hematologic malignancies.

Testis cancer has become one of the most curable of all solid malignancies. More than 95% of patients should be cured with appropriate treatment and should have few long-term treatment-related side effects. Current chemotherapy for advanced testis cancer has resulted from an orderly sequence of chemotherapy trials that serves as a model for cancer chemotherapy development. Recent studies have defined the least therapy required to minimize toxicity while maintaining a high cure rate in "low-risk" patients. Further improvements are necessary in "high-risk" patients; evaluation of new regimens by means of randomized trials is essential.