Tyrosine sulfation is a post-translational modification of proteins that is important to protein-protein interactions. We show that integrins, a family of trans-membrane receptors found in animals that link cells to the Extracellular Matrix, have a high number of likely tyrosine sulfation sites. Particularly, likely tyrosine sites in integrins are often found near ligand binding or recognition sites. Our data also show a high degree of conservation between likely sulfated tyrosine sites, suggesting their functional importance to the integrin.

Antiporters are generally responsible for ion homeostasis in the model organism Arabidopsis thaliana by exchanging hydrogen ions (H+) for sodium (Na+) or potassium (K+). However, information regarding the role of NHX2 and NHX3 in this process is scarce; therefore, this study aims to investigate the effect of overexpression of NHX and NHX3 genes individually when the plant is grown in Spalding media with varying concentrations of potassium: 30mM (high), 1mM (medium), and 0.1mM (low). After ten days of growth, root length was measured and then expression of HAK5 and AKT1, which correlate with low levels and high levels of potassium, respectively, were measured using comparative qPCR analysis. The results indicated that though overexpression of the NHX2 gene had little to no effect in any concentration of potassium media, overexpression of the NHX3 gene significantly impacted growth and development. Specimens with an overexpressed NHX3 gene exhibited shorter roots, increased expression of HAK5, and decreased expression of AKT1 in low levels of potassium. Not only do these results present a better understanding of Arabidopsis thaliana, but they may also guide the process of developing better stress response capabilities in crops; abiotic stress is the primary cause of crop loss worldwide.

Tyrosine sulfation is a posttranslational modification of a protein in which the hydroxyl group of the amino acid tyrosine is changed into a sulfate group. This modification strengthens protein-protein interaction. Tyrosine sulfation is prominent in the signature sequence of the conserved selectivity filter of voltage-gated potassium channels. The functionally similar KcsA from bacteria Streptomyces lividans shares this signature sequence. Positively charged toxin binding sites interact with negatively charged sulfated tyrosine sites. Voltage-gated potassium channels function in repolarization of action potentials in the brain, heart, and muscles. Tyrosine sulfation plays a critical role in the conduction of these channels.

Perennial crop plants like grapevine (Vitis vinifera L.) use stored carbohydrates (CHO) from the previous season to sustain early season growth and flower development.  Water deficits inhibit current season growth and yield of the current season and following season, but the effects on stored CHO are not known.  CHO assays were performed on two grapevine genotypes, Grenache and Syrah, across three different irrigation treatments. Specifically, CHO concentrations in basal nodes and internodes were assayed just after the onset of veraison, the onset of ripening, which has been shown to be the annual low point in storage CHO concentrations in grapevine. A series of hot ethanol baths were used to extract soluble sugars. After extraction, CHO samples were digested into glucose using an alpha-amylase and amyloglucosidase solution. A PGO enzyme o-dianisidine dihydrochloride solution was added to each sample for a color reaction. The plate was read using a spectrometer and optical density numbers were recorded and analyzed with a standard starch calibration curve. In general, Syrah had higher storage CHO concentration than Grenache, which suggested that it was more efficient with water. Across both varieties and all three irrigation treatments, internodes contained higher concentration of storage CHO. CHO distribution in internodes supported the hypothesized relationship: decreased water availability results in decreased concentrations of storage CHOs. These data suggest that water deficit and storage CHO concentrations are positively correlated in perennial crop plants like grapevine (Vitis vinifera L.).  CHO in the nodes did not show the predicted distribution. Syrah vines had lower midday leaf water potential than Grenache vines which can be attributed to their anisohydric tendencies. This information on CHO distribution and genotypic variation in response to water deficits is important for identifying water-efficient grapevines and for water-conservation in agriculture.

Acidovorax (formerly Pseudomonas) sp. JS42 is able to use the compounds 2-nitrotoluene (2NT) and nitrobenzene as carbon, nitrogen, and energy sources. In the first step of the degradation pathway, 2-nitrotoluene 2,3-dioxygenase (2NTDO) converts 2NT to 3-methylcatechol with concomitant nitrite release. 2NTDO has three component proteins, and although it can break down all three mononitrotoluene isomers, JS42 cannot grow on 3-nitrotoluene (3NT) or 4-nitrotoluene (4NT). However, it is possible to force JS42 to adapt to 3NT and 4NT with resulting changes to 2NTDO. In this study, we evolved 4NT+ JS42 strains to grow on 3NT using long-term selection. Sequencing of the ntdAc gene encoding the α subunit of 2NTDO oxygenase revealed substitutions at the amino acid position 204 on the active site. Mutations at positions 238 and 248 were conserved from the parent 4NT+ strain and no other mutations were present, supporting the hypothesis that the amino acid position 204 is crucial for the evolution of JS42 to utilize new substrates. The next step of the 2NT degradation pathway involves catechol 2,3-dioxygenase (CDO). Both ctdE1 and ctdE2 encode CDO, and each has an associated regulatory gene (ctdR1 and ctdR2). Based on the phenotype of a mutant strain with deactivated ctdE1, ctdE1 seems critical to the degradation pathway. We will complement the ctdE1 mutants to verify the role of the enzyme in 2NT degradation. It is not yet known whether ctdR1 encodes an inducer or repressor, so ctdR1 inactivation will be used to determine the function of the regulatory protein. 

The atmospheric carbon sequestration abilities of plants, and in specific of grasses, are important on a local and global scale. However, little is known about the difference in carbon sequestration rates of perennial and annual grasses. The goal of this study is to discover if and to what extent grassland restoration, which is commonly achieved by seeding native perennial grasses, increases carbon sequestration through the analysis of soil organic carbon (SOC) stocks. Two sets of soil samples were taken, one set with samples from restored and nearby unrestored sites, and one with pairs of adjacent annual and perennial samples. The soils were processed and analyzed for carbon content in external laboratories. Statistical analysis using JMP revealed that the unrestored sites generally have higher amounts of SOC, although there is a positive relationship between perennial grasses and carbon presence. We conclude that the varying management practices and land use histories greatly shape SOC stocks in grasslands and that there is preliminary evidence that perennial grasses are more effective than annuals in storing carbon. 

Uridine 5’diphopho-α-D-galactopyranoside (UDP-Gal) is a sugar nucleotide commonly used by animals, plants, and bacteria as the activated donor of galactose (Gal).   The salvage pathway is the simplest route to synthesize UDP-Gal and involves three different enzymes: Streptococcus pneumoniae TIGR4 galactokinase (SpGalK), Bifidobacterium longum UDP-sugar pyrophosphorylase (BLUSP), and Pasteurella multocida inorganic pyrophosphatase (PmPpA)1.  The optimum conditions for the entire reaction pathway in a one-pot multienzyme system were determined.  Then, using these conditions, synthesis of UDP-Gal was scaled-up to the gram-scale.  Production of UDP-Gal was successfully attempted using 1 g of Gal and a reaction yield of 70% was obtained.  No isolation yield was determined because of incomplete purification.