Although there are many different species of pepper plants (Capsicum spp.), all are from the New World tropics, and landraces such as Jalapeño (Capsicum annuum cv. Jalapeño) have been selected for optimum performance in response to local abiotic and biotic stresses. Pepper plants produce the phenolic compound capsaicin, primarily in the placenta of fruits, possibly to deter mammalian herbivores in favor of avian frugivores. Capsaicin content is influenced by genetic and environmental conditions including soil moisture and fertility, temperature, and light. In order to explore the relationship between abiotic stress and fruit capsaicin content, Jalapeño pepper plants were grown from seed, and then treated with 0.0, 0.5, 1.0, and 1.5% NaCl solution. Capsaicin extracts from Jalapeño fruits were analyzed using High Performance Liquid Chromatography (HPLC). None of the parameters tested were significantly different between the control or treatment groups, but the following trends were found in the data. Plants at the two highest salinities had higher levels of capsaicin compared to the control and lowest salinity group (0.160 vs. 0.132 mg capsaicin/g dry fruit, respectively). Fluorometry readings of photosynthetic efficiency (Fv/Fm) demonstrated that at 0.0 and 0.5% NaCl plants had a more optimal ratio (0.70) compared to plants treated with 1.0 and 1.5% NaCl (0.63). Total plant biomass did not decrease with increased salinity. However, a root:shoot analysis demonstrated that plants grown in 1.5% NaCl allocated a higher proportion of their photosynthate to root production (0.796) compared to the control plants grown at 0.0% NaCl (0.691). At the highest salinity level plants doubled their fruit production and allocated more of their photosynthate towards sexual reproduction as opposed to vegetative growth. Because of the consistent (although non-significant) trends in the parameters measured, a biological response to increased salinity suggests a true biological response. Therefore, further investigations with higher levels of salt stress or longer growing periods may lead to statistically significant changes in morphometric data and capsaicin production.

We previously described in a paper published in BIOS an undergraduate lab activity involving the gene cloning, expression, and purification of Thermus aquaticus (Taq) DNA polymerase, an enzyme used in the polymerase chain reaction (PCR). Based on the large number of requests for biological materials and questions about the protocols this paper invoked, we explored methods to simplify the protein purification portion of the published lab activity. A faster and simpler protocol would permit labs and classes with limited equipment or supplies the ability to produce active Taq DNA polymerase more easily for both teaching and research use. In the simplified protocol described here, bacterial cell lysis and enzyme purification is achieved in a small starting volume using only a hot water bath, a microcentrifuge, and one simple buffer. The purified enzyme from this protocol works well in PCR, and we additionally describe its use in a 2X master mix.

Zooplankton diel vertical migration (DVM) is a defense mechanism used in planktivory avoidance. We evaluated zooplankton DVM in two lakes of contrasting food webs in Michigan's Upper Peninsula, USA to test the hypothesis that zooplankton follow normal DVM in the presence of a vertebrate zooplanktivore: Pumpkinseed sunfish, Lepomis gibbosus, and reverse DVM in the presence of an invertebrate predator; Chaoborus spp. We found normal DVM in Daphnia spp., cyclopoid copepods, and copepod nauplii populations in the vertebrate zooplanktivore dominated lake. In contrast, cyclopoid copepods and calanoid copepods exhibited reverse DVM in an invertebrate predator dominated lake. Although the magnitude of DVM was minimal in both lakes, our analysis demonstrated that large cladoceran zooplankton are more responsive to vertebrate predation while small size copepod zooplankton are more responsive to invertebrate predation.

Breast cancer is the second leading cause of cancer death in women, with 1 in 8 developing an invasive breast cancer in her lifetime. Changes in gene expression are common as tumors progress and epigenetics studies alterations in gene expression where the coding DNA sequence is not directly changed. One epigenetic method employs DNA methylation in which DNA methyltransferases (DNMTs) can methylate, or silence, genes. A variety of cancer cell lines have been shown to express aberrantly spliced DNMTs. Furthermore, the aberrant transcripts DNMT3B7 and ΔDNMT3B6 have been shown to be highly expressed in invasive breast cancers compared to poorly invasive cells. Interestingly, DNMT3B7 was shown to methylate the E-cadherin gene, CDH1. The loss of E-cadherin expression and p120 isoform alterations is a hallmark of tumor progression to a more invasive state. Recently, it has been shown that loss of E-cadherin expression can activate the Ras/MAPK pathway via p120 and Rac signaling in breast cancer cells. Based on these data, we hypothesize that the expression of DNMT3B7 and ΔDNMT3B6 in breast cancer cells decreases E-cadherin expression, thus promoting tumor progression through over-activation of the Ras/MAPK pathway via p120. This study gives clear evidence of expression changes in E-cadherin and p120 isoforms leading to the activation of Rac and the Ras/MAPK pathway in the highly invasive MDA-MB-231 breast cancer cell line as compared to the poorly invasive MCF-7 breast cancer cells. Future studies on this topic may lead to the development of novel therapeutics in the treatment of breast cancer.

Alterations in nucleolar morphology and number have been routinely noted by pathologists and tumor biologists. More recently, cancer patient prognosis has been correlated to increases in nucleolar size, number and morphology in tumor sections. This study investigated the nucleolar changes in the well-characterized SV40 T antigen transformation model by assessing B23-positive nucleoli. B23, or nucleophosmin, is essential in rRNA processing and p53 regulation via the sequestration of p19ARF. By using B23 immunofluorescence, we found that cells expressing T antigen manifest significant increases in the number, size and the number of large nucleoli present. The total number of nucleoli is increased significantly in both spontaneously immortalized C57Bl/6 mouse embryo fibroblasts and T antigen transformed cell lines compared to the primary cells; however, the properties of growth rate, saturation density and tumorigenesis correlated to significant increases in nucleolar size, not the total number of nucleoli.

Methicillin-resistant Staphylococcus aureus (MRSA) was isolated from 10 (18.5%) of 54 meat samples collected in central Kentucky. Meat specimens were collected from six local markets in the central Kentucky region. MRSA found in meat samples may be a possible source for community-associated infections of MRSA. There were nine samples obtained from each location (18 pork, 18 beef, and 18 processed meats). The specimens were placed on ice for transport to the lab where they were individually processed using an aseptic technique. Meat samples were streaked for isolation on mannitol salt agar plates (MSA) and placed in 7% salt enrichment broth upon arrival in the laboratory. MSA isolates that fermented mannitol were tested for the presence of Staphylococcus aureus (S. aureus) with the coagulase and d-trehalose fermentation test. S. aureus isolates were placed on the oxacillin agar screen test (Mueller Hinton Agar with 6 μg/mL oxacillin and 4 % NaCl) to determine if MRSA was present. The positive specimens accounted for 27.7% of both pork and beef samples tested.

The following chapters have sent in officer slates for 2011-2012. 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.