The mechanisms of transepithelial absorption of dietary D-glucose and D-fructose in the American lobster, Homarus americanus, were investigated in this study in order to determine whether sugar transport proteins have been conserved throughout evolution. Whole lobster intestine was isolated and mounted in a perfusion chamber to determine transepithelial mucosal to serosal (MS) and serosal to mucosal (SM) mechanisms of 3H-D-glucose and 3H-D-fructose transport across the intestine. Unidirectional MS and SM fluxes were measured by adding variable concentrations of 3H-D-glucose and 3H-D-fructose (2.5 to 50uM) to either the perfusate or the bath respectively and sampling the amount of radioactivity that exited the opposite side of the intestine. Both the transepithelial MS and SM transports of 3H-D-glucose and 3H-D-fructose were hyperbolic functions of sugar concentration. The net flux of both sugars indicated a net absorption of D-glucose and D-fructose into the serosal compartment. Inhibitory analysis showed that while phloridzin decreased MS 3H-D-glucose transport via a sodium glucose transport (SGLT 1-like) protein located on the mucosal membrane, 3H-D-fructose transport was not affected by the drug. Mucosal phloretin decreased MS D-fructose transport but not MS D-glucose transport. Immunohistochemistry analysis revealed the presence of a mucosal GLUT 5 transport protein on the mucosal membrane. Increasing serosal concentrations of phloretin decreased both SM D-glucose and D-fructose transport suggesting the presence of a serosal GLUT 2 used by both sugars. The results of this study support the concept of conserved mechanisms of sugar transport in multicellular animals.

The prototype Alphavirus, Sindbis virus (SIN), relies on cyclic transmission between the mosquito and vertebrate hosts in order to be maintained in nature. This broad host range suggests that alphaviruses use a universally expressed molecule for attachment. Heparan sulfate proteoglycan (HSPG), a ubiquitous SIN receptor present on the cell surface of most eukaryotic cells, has been reported in the salivary glands and midguts of mosquitoes. These organs are essential for virus transmission from this hematophageous invertebrate. Variable host cell response in the mosquito following intrathoracic inoculation with SIN has been documented. In this study, per os infection of Aedine species with variants of SIN was used to determine organ specific responses to virus as well as the temporal kinetics of SIN dissemination via leg assay. Analysis indicated AR339 virus dissemination in samples at day 14 days post infection (p.i.). TR339 was identified at day 12 in legs of virus fed individuals. AR339, the HSPG adapted variant resulted in SIN-associated pathology in salivary glands of Aedes albopictus. This pathology was limited to lateral lobes, while the median lobe remained unaffected. Infection with TR339, a HSPG-independent variant, did not result in virus-associated pathology in the salivary gland to day 28 post infection. Immunohistochemistry determined that HSPG was located in the lateral lobe duct region of the salivary glands. It has been suggested that human lactoferrin (hLF) may interfere with virus receptor attachment and is involved in inhibition of virus infection in vertebrate cells. To that end, the effects of bovine LF inhibition on virus attachment were compared between AR339 and TR339 in the mosquito cell line C7-10. Cytopathic effect was observed earlier and with greater intensity in TR339 infected monolayers when compared to AR339 infected monolayers. This suggests that bovine LF has an inhibitory effect on AR339 infection in invertebrate cells, possibly due to this variants use of HPSG for attachment.

Isolated populations that inhabit various geographic and climatic ranges tend to diverge in their life history tactics. When development time is constrained by unfavorable seasons, often an organism must trade-off the investment of resource allocation between somatic and reproductive growth. The variation in reproductive tactics and juvenile hormone titers were studied among three populations of Romalea microptera from Athens, GA, Jacksonville, FL, and Miami, FL, all of which exist on a latitudinal cline. The Athens population was significantly younger at oviposition and gained significantly less body mass than both the Jacksonville and Miami populations, which did not differ from each other. Clutch mass did not differ across populations. With respect to both body size and oviposition age, Athens invested significantly more (measured by clutch size) to their first clutch than either Jacksonville or Miami, which did not differ from each other. Juvenile hormone and lipid profiles did not differ among populations. In response to the markedly reduced season length, results suggest that Athens grasshoppers respond with reproductive tactics that support terminal investment by investing more energy in less time to reproduction, at the expense of future reproduction.

Basigin, the mouse form of the human protein EMMPRIN, is commonly found as a transmembrane homodimer with carboxy termini in the cytosol and extracellular amino-termini. Because of its important role as a cell-to-cell junction molecule, and possible implications for cancer research, a Basigin null mouse was developed in 1996 by Igakura et al., to aid in the study of this protein. Their early research demonstrated that Basigin plays a large role in embryonic development. Mice lacking the Basigin gene are blind from the time of eye opening, and have demonstrated a lack of aversion to offensive odors such as acetic acid and isogine, as well as increased sensitivity to electric foot shock (Naruhashi et al., 1997). Further research demonstrated that Basigin is associated with cell-to-cell communication within the retina of the eye (Ochrietor et al., 2002), and in the olfactory system (Igakura et al., 1996). It is thought that Basigin acts as a chaperone for several Monocarboxylate Transporters (MCTs), accompanying them for proper placement in the cell membrane. The focus of this current study is to explore the role and function of Basigin in the olfactory bulb of the mouse. Data from biochemical analysis of tissue samples show that MCTs in the olfactory bulb are unaffected by absence of Basigin. Further study involving immunohistochemistry reveals that MCT2 is the most abundant transporter present in normal olfactory bulbs, and that a metabolic defect does not likely underlie the anosmia exhibited by Basigin null mice.

Papillomaviruses are a genera of small tumor viruses in the Papovaviridae family, whose lifecycle and replication ability is directed by epithelial differentiation. During latency, papillomavirus DNA replication occurs synchronously with the host cell's replication by the activation of the El protein. To elucidate the effects upon viral replication, this study utilized chemical inhibition of several kinases predicted to phosphorylate, and subsequently modify the activity of, the papillomavirus' E1 protein. The amount of DNA replicated was observed via autoradiography following DNA extraction and southern blotting of BPV-transformed C127 cells. Sample extracts from cells exposed to specific chemical inhibitors of PKC, CDK, and DNAPK showed a consistent and significant decrease in viral DNA when compared to the DNA abundance of a control set of extracts. Extracts of cells subjected to inhibition of CK2 displayed an observable increase in replicated viral DNA. To ensure that the kinase modification was not effecting the growth or viability of the cells, a neutral red assay was performed and found no significant difference between control and chemically treated samples in cell viability or overall cell number. These findings, in conjunction with the differential viral DNA abundance, implicate that kinases PKC, CDK, CK2, and DNAPK, have a role in viral genome replication.

Cold temperatures are thought to be among the most important determining factors of geographic distribution for tropical and sub-tropical marine invertebrates. The Asian green mussel, Perna viridis, has been introduced into coastal waters of Florida where its current distribution is hypothesized to be limited by low temperatures during winter. Lethal and sublethal effects (heat shock protein/ Hsp70 expression) of cold water and air temperatures were analyzed in two size classes of P. viridis from Florida in an effort to determine the effects of current and forecasted temperatures on the potential for range expansion. Mussels were exposed to water temperatures of 14, 10, 7 and 3°C for up to 30 days, or to air temperatures of 14, 7, 0 and -10°C for periods of two hours. Mortality was significantly increased at all water and air temperatures ≤ 14°C. No consistent differences in mortality rates were observed between small (15-45mm) and large (75-105mm) size classes after exposure to either cold water or air. Significant increases in Hsp70 expression were observed after a two hour exposure to 10°C water, but Hsp70 expression was not significantly increased at any temperatures in which mortality was not also significant. The temperature threshold for survival in this population appears to be between 10-14°C which suggests that under current conditions, P. viridis may already be at the northern edge of its potential range in the United States. However, if water temperatures increase in association with global climate change, northerly flowing currents may permit range expansion as temperatures allow.

The current study is a characterization of L-leucine absorption across the American lobster intestine in order to determine the likelihood of a bis-complex formation with zinc ([Leu]-Zn-[Leu]) as a possible substrate for PEPT1. This study required isolated lobster intestines to be mounted in a perfusion chamber in order to quantify 3H-L-leucine transport. It was hypothesized that an apical dipeptide transporter, PEPT1, was responsible for uptake of L-leucine via formation of a bis-complex with zinc ([Leu]-Zn-[Leu]) in the form of molecular mimicry, where the bis-complex mimics the normal dipeptide substrate of the proposed carrier system. It was found that L-leucine transport across the lobster intestine was significantly stimulated by luminal zinc and other cations and that this stimulation led to enhanced net flux of the amino acid across the intestine compared to its net flux in the absence of these cations. Transmural transport ofL-leucine was also significantly stimulated by a variety of organic solutes including L-histidine, L-cysteine, and glycylsarcosine (GLY-SAR) by way of countertransport. While many observations in the present study suggest that PEPT1 may be the carrier system responsible for transmural leucine transport in the presence of zinc, other cation-dependent carrier systems, such as the B^0 transporter, with strong transstimulation properties, may also be a suitable candidate for leucine transport in the lobster intestine.

Many hydrophobic environmental pollutants have been shown to bioaccumulate and biomagnify at high levels in sharks due to their high liver lipid content, high trophic level, and life history characteristics. Studies have demonstrated that the levels of pollutants present in shark tissues can not only exceed the recommended levels for human consumption, but that, in some cases, they are also greater than the threshold for physiological effect in other aquatic species. However, few studies to date have investigated the biological effect of environmental exposure to contaminants in sharks. Therefore, the goal of this study was to investigate, through the use of biomarkers, if sharks are experiencing physiological effects due to exposure to 1) methylmercury (MeHg) and 2) polycyclic aromatic hydrocarbons (PAHs). The results of the first part of the study indicated that total mercury (THg) concentrations (μg/g w.w.) in Sphyrna tiburo muscle tissue were positively correlated with size of the animals, but that metallothionein (MT), a commonly used biomarker for toxic metal exposure, was not a valid biomarker for Hg exposure in this species, as no correlation between MT in muscle or liver and THg was found. The later portion of the study demonstrated that sharks off the coast of Alabama that were exposed to oil from the Deepwater Horizon oil spill (DHOS) in 2010 are exhibiting biochemical effects in the form of induced activity of the Phase I biotransformation enzyme, cytochrome P4501A1 (CYP1A1). Further research on the effects of both MeHg and PAH exposure in sharks should focus on the effects experienced by larger species and those at higher trophic levels, which are known to harbor higher levels of contaminants, and therefore be affected to a greater extent, than the species analyzed in this study (i.e. small species occupying lower trophic levels).

Basigin and Embigin are members of the immunoglobulin superfamily that function as cell adhesion molecules. Studies of Basigin null mice revealed reproductive sterility, increased pain sensitivity, and blindness. It is thought that the mechanism causing blindness involves misexpression of monocarboxylate transporter 1 (MCT1) in the absence of Basigin. It is known that the transmembrane domain of Basigin interacts with MCT1. In the absence of Basigin, MCT1 does not localize to the plasma membrane of expressing cells and photoreceptor function is disrupted. Studies of the Basigin null mouse brain suggest that MCT1 is properly expressed, which suggests a separate mechanism causes the increased pain sensitivity in these animals, and also that a different protein directs MCT1 to the plasma membrane of expressing cells in mouse brain. Embigin is known to interact with MCT2 in neurons and with MCT1 in erythrocytes. It is not known, however, if Embigin normally interacts with MCT1 in the mouse brain or if Embigin acts to compensate for the lack of Basigin in the Basigin null animals. Therefore, the purpose of this study was to determine if Embigin normally interacts with MCT1, 2, or 4 in the mouse brain and if so, whether the interaction is similar to that between Basigin and MCT1. Expression of Basigin, Embigin, MCT1, MCT2, and MCT4 in mouse brain was assessed via immunoblotting and immunohistochemical analyses. In addition, recombinant protein probes corresponding to the Embigin transmembrane domain were generated for ELISA binding assays using endogenous mouse brain MCTs. It was determined that the proteins in question are rather ubiquitously expressed throughout the mouse brain, and that the cell adhesion molecules Basigin and Embigin may be co-expressed in the same cells as the MCT2 and MCT4 transporter proteins. In addition, it was determined that the Embigin transmembrane domain does not interact with the MCTs. The data therefore suggest that MCTs do not require Basigin or Embigin for plasma membrane expression in mouse brain.

The goal of ecological restoration is to return degraded or altered ecosystems to their pre-disturbed state with respect to ecosystem structure, function, and composition. In the current study the research objective was to reestablish high levels of biodiversity on two restored pine plantations as well as restore a native pine flatwoods ecosystem. Managed, even-aged pine flatwoods are now the most extensive ecosystem in North Florida, comprising approximately 70% of the forested landscape. Slash pine trees were thinned in the experimental plots to restore the natural slash pine density of native ecosystems. In addition to the thinning treatments, experimental plots have been clear-cut and all vegetation removed from the plots. Arthropods were sampled by employing pitfall traps, sticky traps and sweep netting. This study assesseed the success of the restoration techniques employed by looking at biodiversity with a fine-resolution, taxonomically narrow approach by identifying the arthropods down to the taxonomic level of family and determining the number of morphospecies. Species were also subdivided into functional groups based upon the ecosystem services that they provide and their trophic level. Analyses revealed that arthropod species and guild diversity was not significantly affected by treatments in both 2008 and 2009. The experimental treatments were able to recover to pre-disturbance levels after two years following restoration. This indicates that these arthropod communities are fairly resilient and are able to recover fairly quickly following perturbation. Interestingly, community similarity measures revealed that although the experimental treatments were no more diverse than control plots the community species composition was fairly dissimilar between treatments, with plots becoming more dissimilar from 2008 to 2009. More long term data should reveal if these plots are proceeding along different successional trajectories in terms of community species composition and also will allow us to gain more insight into the long term effect of the treatments on biodiversity.