Metal corrosion resulting from microbial processes constitutes a serious expense in many industrial applications. Oil pipelines are plagued by these events leading not only to economic losses but also severe environmental consequences. Therefore, our understanding of the microorganisms that contribute to metal corrosion is vital. Here, the roles of a methanogen and either a sulfate-reducing bacterium or archaeon in corrosion are addressed. The methanogen Methanothermobacter thermautotrophicus was used to assess the effect of methanogenesis in corrosion. The sulfate-reducing bacterium Desulfomicrobium thermophilum and the sulfate-reducing archaeon Archaeoglobus fulgidus were used to measure the effect of sulfate reduction on corrosion. To assess the combined effect of sulfate-reduction and methanogenesis on corrosion, M. thermautotrophicus was grown in combination with A. fulgidus or D. thermophilum. This allowed investigation of corrosion impact at different temperatures and salinities. All organisms contributed to corrosion, measured by metal weight loss over time, either independently or in conjunction with a partner organism. Corrosion resulting from strictly biotic processes was dominant at lower temperature and salinities. At higher salinities and temperatures, approximately half of the corrosion measured was because of abiotic reactions as indicated by experimental controls. This work demonstrates the role of these microbial metabolisms in metal corrosion in anaerobic environments.

Ribosomal RNA analyses of soil microbial communities consistently indicate that the majority of microorganisms in soil have never been cultivated or described in the laboratory. It has been suggested that microorganisms fail to grow in traditional culture media because the media fails to simulate the organisms' natural environment. We designed a unique culture technique that can cultivate an average of 40% and as high as 90% of the bacteria present in a soil sample. The 16S rDNA of 50 of these isolates were PCR amplified, sequenced, and analyzed. Nineteen, 26, 2 and 3 of the isolates were affiliated with the phyla Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes, respectively. Ten isolates possessed less than 98% sequence similarity to any previously characterized organism.

Inonotus obliquus (also known as Chaga) is a fungal parasite of birch trees that has been prized in folkloric medicine for centuries due to its curative powers against cancer and infectious diseases. Over the past decade, a number of studies have examined the anti-tumor properties of various Chaga extracts and demonstrated remarkable efficacy of this natural product in the treatment of solid tumors in mice. We sought to determine if ethanol extracts from Chaga affected the oncogenic properties of cultured melanoma cells. Treatment of B16F1 mouse melanoma cells with fresh ethanol extracts of Chaga resulted in strong increases in melanocyte dendricity as evidenced by increases in the number of cells with dendritic projections, the number of projections per cell, and total projection length. Chaga treatment led to cell cycle disruption as evidenced by decreased steady state cyclin mRNA expression and an increase in the number of cells in the G2 phase of the cell cycle. Moreover, Chaga treatment led to melanoma cell toxicity in a dose dependent manner. These data suggest that ethanol extracts of Chaga may have the potential as an anti-melanoma treatment.

Fluorescent probes such as fura-2 and its relatives mag-fura-2 and fura-2FF are used to detect changes in intracellular ions such as Ca² and Mg² . However, they are sufficiently non-selective to record changes in other species such as Zn² , Cd² , Fe² and other transition metals. In the present study we have characterized the responses of these three dyes to Zn² and Cd² , in a buffered salt solution using spectrofluorophotometry. Fura-2, mag-fura-2 and fura-2FF generally reacted to increasing concentrations of Zn² or Cd² with a shift in the excitation spectra. We found that for a given probe the Zn² and Cd² excitation spectra were broadly similar, but isosbestic and peak wavelengths were useful in distinguishing between the two metals.

Organisms cannot maximize all life functions and therefore must allocate resources to maximize reproductive fitness such that they produce the highest number of surviving offspring. The object of the experiment was to evaluate variation of fruit morphology to determine how Opuntia littoralis optimizes reproductive investment. The experiment focused on fruit volume, sugar concentration, number of seeds and average seed mass on two different aspects (polar-facing and equatorial-facing slopes) in Temescal Canyon Gateway Park, Pacific Palisades, California. The results revealed fruit volume was positively correlated with number of seeds, sugar concentration was positively correlated with number of seeds, and average seed mass was negatively correlated with number of seeds. The study suggests that variation in Opuntia fruit morphology can be explained by the principle of allocation and life history strategies rather than by microhabitat variation alone.

In Arabidopsis thaliana, the GLABRA 1 (GL1) gene encodes a R2R3-MYB transcription factor that regulates epidermal genes necessary to promote trichome initiation. To determine whether the GL1 gene is also involved in the stomatal patterning of rosette leaves, the epidermal cell pattern of a glabrous mutant (gl1-1) was compared to that of the wild type Columbia ecotype. The gl1-1 mutant was found to have lower stomatal densities and greater distances between stomata as compared to the Columbia ecotype. These findings suggest that stomatal patterning and trichome developmental processes share genetic components to specify cell fate and identity.

This project sought to characterize plant defense investment in the castor bean (Ricinus communis L.), an exotic myrmecophyte in southern California, with respect to life history strategies. Experimental evidence suggests that exotic myrmecophytes can form mutually beneficial associations with exotic ants regardless of the differences in shared evolutionary histories. Castor bean plant investment in defense was evaluated by measuring the area on extra-floral nectary (EFN) glands. Life history strategies may change with respect to plant size and was therefore evaluated in terms of basal stem diameter (<50mm). We hypothesized that smaller and younger castor bean plants would have bigger EFN glands than larger and older plants. We found that EFN gland size was not correlated to castor bean class size. This suggests that in southern California, biotic plant defense is not optimized in castor bean plants. As an r-selected species, the castor bean plant compromises investment in plant defense favoring investment in growth and early reproduction.

We evaluated the effects of an irrigation system on the community structure of arthropods in a coastal sage scrub chaparral habitat. We placed 5 traps in the irrigated site and 5 traps in control site, for a total of 10 sticky traps (using Tree Tanglefoot) in an area adjacent to Ballona Wetlands in Los Angeles, California. The traps were set at the irrigated and non-irrigated site on Telegraph Weed for one week. Results showed that morphospecies richness, relative abundance, and taxonomic order representation were higher at the control site than at the irrigated site. Our study documents how anthropogenic impacts in a coastal sage scrub habitat can alter the community composition of invertebrates in the fringe habitats surrounding the last wetlands in Los Angeles County.

The following chapters have sent in officer slates for 2012-2013. Officers are listed in the order of President, Vice President, Secretary, Treasurer, Historian, and Faculty Advisor unless otherwise noted. The chapters are listed alphabetically by Greek name. Please submit new slates, changes and corrections to Lori.Kelman@montgomerycollege.edu.