Antimicrobial Activities of Laetiporus conifericola (Agaricomycetes) from the United States.

In this study, samples of polypore mushroom Laetiporus conifericola were collected from Pennsylvania, USA. The antimicrobial activity (AMA) of ethanolic, methanolic, and water extracts of this fungus were tested in vitro by the agar diffusion test against some selected clinically important microorganisms. These microorganisms included three Gram-positive bacteria (Staphylococcus aureus 5W1941, S. epidermidis 85W1940, and Bacillus cereus 85W1815), three Gram-negative bacteria (Escherichia coli 85W1860, Salmonella typhimurium 85W1956, and Pseudomonas aeruginosa 85W1903), and one fungus (Candida albicans). These extracts demonstrated varying degrees of inhibition against all of the test pathogenic microorganisms except C. albicans. Methanolic and ethanolic extracts of L. conifericola were very effective against S. aureus, while the aqueous extract was the least effective. All tested extracts were effective against S. epidermidis, methanolic extract produced the best zone of inhibition followed by the aqueous extract while ethanolic extract had the least zone of inhibition. B. cereus and P. aeruginosa were highly susceptible to ethanol extract. In addition, the growth of E. coli was best inhibited by the aqueous extract, followed by the methanolic and ethanolic extracts, respectively. The aqueous and methanolic extracts were most effective against S. typhimurium; however, this bacterium was not susceptible to ethanolic extract. The significance of these findings is discussed.

High prevalence of discordant human papillomavirus and p16 oropharyngeal squamous cell carcinomas in an African American cohort.

BACKGROUND: Most studies on human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (SCC) have been performed on white Americans. Our study examined the incidence of HPV in an African American oropharyngeal SCC cohort and its survival. METHODS: African American patients with oropharyngeal SCC in a combined tumor registry were identified. HPV16 testing was performed by polymerase chain reaction (PCR) from DNA extracted from tumor blocks. The p16 staining was performed using standard immunohistochemistry. RESULTS: Forty-four patients were identified for analysis. Seventy-three percent of the tumors were HPV-positive. Only 39% of the patients who were HPV-positive were also p16-positive. Survival between all 3 tumor types, patients who tested HPV-positive/p16, HPV-positive/p16-positive, and HPV-negative/p16-negative was significantly different (p = .03). HPV/p16 status was significant on univariate and multivariate analysis. CONCLUSION: HPV oropharyngeal SCC is strongly present in this African American cohort. Two thirds of the patients who were HPV-positive were p16-negative. Greater study is needed to explain the high p16 negativity among this HPV-positive oropharyngeal SCC African American cohort. © 2015 Wiley Periodicals, Inc. Head Neck 38: E867-E872, 2016.

NNK reduction pathway gene polymorphisms and risk of lung cancer.

The tobacco-specific nitrosamine NNK is a potent carcinogen found in tobacco smoke and implicated in the development of lung cancer. The major route of NNK metabolism is carbonyl reduction by AKR1C1, AKR1C2, CBR1, and 11ß-HSD1 to form NNAL. This study investigated the potential role of variants in this pathway on lung cancer risk by examining 53 tag-SNPs representing the common variations in AKR1C1, AKR1C2, CBR1, and HSD11B1 in 456 lung cancer cases and 807 controls. One SNP in CBR1 (rs2835267) was significantly associated with overall risk of lung cancer, but did not pass multiple testing adjustment (OR: 0.76 95% CI: 0.58-0.99, P = 0.048, FDR P = 0.20). After stratification and multiple testing correction, three SNPs showed significance. One SNP (rs2835267) in CBR1 showed a significant decreased risk for smokers with a high pack-years (OR: 0.3595% CI: 0.17-0.69, P = 0.018) and in SCC (OR: 0.4895% CI: 0.29-0.76, P = 0.018). Another SNP located in CBR1 (rs3787728) also showed a significant decreased risk in SCC (OR: 0.4695% CI: 0.26-0.80, P = 0.024) and small cell carcinoma (only in current smokers) (OR: 0.06895% CI: 0.01-0.42, P = 0.028). The HSD11B1 SNP (rs4844880) showed a significant increased risk for adenocarcinoma within former smokers (OR: 3.9495% CI: 1.68-9.22, P = 0.011). Haplotype analysis found significance with six haplotypes and lung cancer risk. These findings indicate that select variants in genes in the carbonyl reduction pathway of NNK may alter the risk of lung cancer.

A non-glycosylated, plant-produced human monoclonal antibody against anthrax protective antigen protects mice and non-human primates from B. anthracis spore challenge.

The health and economic burden of infectious diseases in general and bioterrorism in particular necessitate the development of medical countermeasures. One proven approach to reduce the disease burden and spread of pathogen is treatment with monoclonal antibodies (mAb). mAbs can prevent or reduce severity of the disease by variety of mechanisms, including neutralizing pathogen growth, limiting its spread from infected to adjacent cells, or by inhibiting biological activity of toxins, such as anthrax lethal toxin. Here, we report the production of glycosylated (pp-mAb (PA) ) and non-glycosylated (pp-mAb (PANG) ) versions of a plant-derived mAb directed against protective antigen (PA) of Bacillus anthracis in Nicotiana benthamiana plants using agroinfiltration. Both forms of the antibody were able to neutralize anthrax lethal toxin activity in vitro and protect mice against an intraperitoneal challenge with spores of B. anthracis Sterne strain. A single 180 µg intraperitoneal dose of pp-mAb (PA) or pp-mAb (PANG) provided 90% and 100% survival, respectively. When tested in non-human primates, pp-mAb (PANG) was demonstrated to be superior to pp-mAb (PA) in that it had a significantly longer terminal half-life and conferred 100% protection against a lethal dose of aerosolized anthrax spore challenge after a single 5 mg/kg intravenous dose compared to a 40% survival rate conferred by pp-mAb (PA) . This study demonstrates the potential of a plant-produced non-glycosylated antibody as a useful tool for the treatment of inhalation anthrax.

Inducible expression in plants by virus-mediated transgene activation.

We have developed a plant virus-mediated transgene activation (VMTA) system that utilizes a viral expression vector to present the inducer. The concept was tested using two well characterized components: (i) an artificial promoter based on the yeast GAL4 upstream activating sequence and the minimal TATA element of Cauliflower Mosaic Virus 35S RNA promoter, and (ii) a transcriptional activator (TA) consisting of a fusion between the GAL4 DNA binding domain and the Herpes simplex virus VP16 activation domain. The TA was expressed under the control of the subgenomic promoter of a Tobacco Mosaic Virus-based expression vector. The VMTA system was functional in transient Agroinfiltration assays with the reporter gene beta-glucuronidase, the intracellular domain of the diabetes associated autoimmune antigen, IA-2ic, and with the anti-tetanus antibody 9F12. Transgenic lines harboring the reporter gene were also examined. The VMTA system displayed tight transcriptional control in both transient assays and in transgenic Nicotiana benthamiana plants carrying the TA-inducible reporter.

Sites and regulation of auxin biosynthesis in Arabidopsis roots.

Auxin has been shown to be important for many aspects of root development, including initiation and emergence of lateral roots, patterning of the root apical meristem, gravitropism, and root elongation. Auxin biosynthesis occurs in both aerial portions of the plant and in roots; thus, the auxin required for root development could come from either source, or both. To monitor putative internal sites of auxin synthesis in the root, a method for measuring indole-3-acetic acid (IAA) biosynthesis with tissue resolution was developed. We monitored IAA synthesis in 0.5- to 2-mm sections of Arabidopsis thaliana roots and were able to identify an important auxin source in the meristematic region of the primary root tip as well as in the tips of emerged lateral roots. Lower but significant synthesis capacity was observed in tissues upward from the tip, showing that the root contains multiple auxin sources. Root-localized IAA synthesis was diminished in a cyp79B2 cyp79B3 double knockout, suggesting an important role for Trp-dependent IAA synthesis pathways in the root. We present a model for how the primary root is supplied with auxin during early seedling development.

Human-derived, plant-produced monoclonal antibody for the treatment of anthrax.

The unpredictable nature of bio-terrorism compels us to develop medical countermeasures that will enable authorities to treat individuals exposed to agents such as anthrax. We report the feasibility of producing a protective, human-derived, monoclonal antibody directed against the protective antigen (PA) of Bacillus anthracis in plants. This was achieved by transient expression using agroinfiltration of Nicotiana benthamiana plants. The resulting antibody was able to neutralize toxin activity in vitro and in vivo at a comparable level to that seen for its hybridoma-produced counterpart.

Trp-dependent auxin biosynthesis in Arabidopsis: involvement of cytochrome P450s CYP79B2 and CYP79B3.

The plant hormone auxin regulates many aspects of plant growth and development. Although several auxin biosynthetic pathways have been proposed, none of these pathways has been precisely defined at the molecular level. Here we provide in planta evidence that the two Arabidopsis cytochrome P450s, CYP79B2 and CYP79B3, which convert tryptophan (Trp) to indole-3-acetaldoxime (IAOx) in vitro, are critical enzymes in auxin biosynthesis in vivo. IAOx is thus implicated as an important intermediate in auxin biosynthesis. Plants overexpressing CYP79B2 contain elevated levels of free auxin and display auxin overproduction phenotypes. Conversely, cyp79B2 cyp79B3 double mutants have reduced levels of IAA and show growth defects consistent with partial auxin deficiency. Together with previous work on YUCCA, a flavin monooxygenase also implicated in IAOx production, and nitrilases that convert indole-3-acetonitrile to auxin, this work provides a framework for further dissecting auxin biosynthetic pathways and their regulation.