Substantial evidence indicates that amino acid conjugates of indole-3-acetic acid (IAA) function in auxin homeostasis, yet the plant enzymes involved in their biosynthesis have not been identified. We tested whether several Arabidopsis thaliana enzymes that are related to the auxin-induced soybean (Glycine max) GH3 gene product synthesize IAA-amino acid conjugates. In vitro reactions with six recombinant GH3 enzymes produced IAA conjugates with several amino acids, based on thin layer chromatography. The identity of the Ala, Asp, Phe, and Trp conjugates was verified by gas chromatographymass spectrometry. Insertional mutations in GH3.1, GH3.2, GH3.5, and GH3.17 resulted in modestly increased sensitivity to IAA in seedling root. Overexpression of GH3.6 in the activation-tagged mutant dfl1-D did not significantly alter IAA level but resulted in 3.2-and 4.5-fold more IAA-Asp than in wild-type seedlings and mature leaves, respectively. In addition to IAA, dfl1-D was less sensitive to indole-3-butyric acid and naphthaleneacetic acid, consistent with the fact that GH3.6 was active on each of these auxins. By contrast, GH3.6 and the other five enzymes tested were inactive on halogenated auxins, and dfl1-D was not resistant to these. This evidence establishes that several GH3 genes encode IAA-amido synthetases, which help to maintain auxin homeostasis by conjugating excess IAA to amino acids.

A2E, an important constituent of lipofuscin in human retinal pigment epithelium (RPE), is thought to mediate light-induced oxidative damage associated with aging and other ocular disorders. Ocular carotenoids in overlying retinal tissues were measured by HPLC and mass spectrometry and were correlated with levels of RPE A2E. We observed a statistically significant increase in total A2E levels in human RPE/choroid with age, and A2E levels in macular regions were approximately 1/3 lower than in peripheral retinal regions of the same size. There was a statistically significant inverse correlation between peripheral retina carotenoids and peripheral RPE/choroid A2E. Prospective carotenoid supplementation studies in Japanese quail demonstrated nearly complete inhibition of A2E formation and oxidation. These findings support current recommendations to increase dietary intake of xanthophyll carotenoids in individuals at risk for macular degeneration and highlight a new potential mechanism for their protective effects--inhibition of A2E formation and oxidation in the eye.

As in humans and monkeys, lutein [(3R,3′R,6′R)-βε, -carotene-3,3′-diol] and zeaxanthin [a mixture of (3R,3′R)-β,β-carotene-3,3′diol and (3R,3′S-meso)-β,β-carotene-3,3′-diol] are found in substantial amounts in the retina of the Japanese quail Coturnix japonica. This makes the quail retina an excellent non-primate small animal model for studying the metabolic transformations of these important macular carotenoids that are thought to play an integral role in protection against light-induced oxidative damage such as that found in age-related macular degeneration (AMD). In this study, we first identified the array of carotenoids present in the quail retina using C30-HPLC coupled with inline mass-spectral and photodiode-array detectors. In addition to dietary lutein (2.1%) and zeaxanthin (11.8%), we identified adonirubin (5.4%), 3′-oxolutein (3.8%), meso-zeaxanthin (3.0%), astaxanthin (28.2%), galloxanthin (12.2%), ε,ε-carotene (18.5%), and β-apo-2′-carotenol (9.5%) as major ocular carotenoids. We next used deuterium-labeled lutein and zeaxanthin as dietary supplements to study the pharmacokinetics and metabolic transformations of these two ocular pigments in serum and ocular tissues. We then detected and quantitated labeled carotenoids in ocular tissue using both HPLC-coupled mass spectrometry and non-invasive resonance Raman spectroscopy. Results indicated that dietary zeaxanthin is the precursor of 3′-oxolutein, β-apo-2′-carotenol, adonirubin, astaxanthin, galloxanthin, and ε, ε-carotene, whereas dietary lutein is the precursor for mesozeaxanthin. Studies also revealed that the pharmacokinetic patterns of uptake, carotenoid absorption, and transport from serum into ocular tissues were similar to results observed in most human clinical studies. KeywordsCarotenoid; Retina; Japanese quail; Lutein; Zeaxanthin; HPLC; APCI-MS Epidemiological and clinical studies in humans have generally demonstrated that there is an inverse relationship between nutritional consumption of antioxidants and prevalence of old age ocular disorders such as age-related macular degeneration (AMD) and cataract (1,2). The carotenoids lutein and zeaxanthin are notable examples because they are specifically concentrated in ocular tissues at high concentrations, and they are excellent absorbers of phototoxic blue light and reactive oxygen species (3,4). Studies using data from the Eye Disease Case Control (EDCC) Study Group have demonstrated that individuals with high blood levels of lutein and zeaxanthin and high consumption of foods rich in these same carotenoids had significantly lower risk of exudative AMD, and several follow up studies including the Age- † This work was supported by National Institute of Health Grant EY-11600 and by Research to Prevent Blindness, Inc. (New York, NY). In the human retina, dietary lutein [(3R,3′R,6′R)-β,ε-carotene-3,3′-diol] and zeaxanthin [(3R, 3′R)-β,β-carotene-3,3′-diol] are unevenly distributed in the retina, with millimolar concentrations found at the fovea with a lutein:zeaxanthin ratio of 1:2 and a...

Bombyx mori-derived silk fibroin (SF) has recently gained interest for its intrinsic or engineered adhesive properties. In a previous study by our group, the mechanism of the protein’s intrinsic adhesiveness to biological substrates such as leather has been hypothesized to rely on hydrogen bond formation between amino acid side chains of SF and the substrate. In this study, the serine side chains of SF were chemically functionalized with substituents with different hydrogen bonding abilities. The effect of these changes on adhesion to leather was investigated along with protein structural assessments. The results confirm our hypothesis that adhesive interactions are mediated by hydrogen bonds and indicate that the length and nature of the side chains are important for both adhesion and secondary structure formation.

Identification of 3-MZ in the macula of aged donors indicates that O-methylation of carotenoids is a potential biomarker for aging and age-related ocular disorders.

Ear infections are a commonly-occurring problem that can affect people of all ages. Treatment of these pathologies usually includes the administration of topical or systemic antibiotics, depending on the location of the infection. In this context, we sought to address the feasibility of a single-application slow-releasing therapeutic formulation of an antibiotic for the treatment of otitis externa. Thixotropic hydrogels, which are gels under static conditions but liquefy when shaken, were tested for their ability to act as drug controlled release systems and inhibit Pseudomonas aeruginosa and Staphylococcus aureus, the predominant bacterial strains associated with outer ear infections. Our overall proof of concept, including in vitro evaluations reflective of therapeutic ease of administration, formulation stability, cytocompatibility assessment, antibacterial efficacy, and formulation lifespan, indicate that these thixotropic materials have strong potential for development as otic treatment products.

Bone metastases are difficult to treat surgically, necessitating a multidisciplinary approach that must be applied to each patient depending on the specifics of their case. The main indications for surgical treatment are a lack of response to chemotherapy, radiation therapy, hormone therapy, immunotherapy, and bisphosphonates which is defined by persistent pain or tumor progression; the risk of imminent pathological bone fracture; and surgical treatment for single bone metastases. An important aspect of choosing the right treatment for these patients is accurately estimating life expectancy. Improved chemotherapy, postoperative radiation therapy, and sustainable reconstructive modalities will increase the patient’s life expectancy. The surgeon should select the best surgical strategy based on the primary tumor and its characteristics, the presence of single or multiple metastases, age, anatomical location, and the functional resources of the patient. Preventive osteosynthesis, osteosynthesis to stabilize a fracture, resections, and reconstructions are the main surgical options for bone metastases. Resection and reconstruction with a modular prosthesis remain the generally approved surgical option to restore functionality, increase the quality of life, and increase life expectancy. Preoperative embolization is necessary, especially in the case of metastases of renal or thyroid origin. This procedure is extremely important to avoid complications, with a major impact on survival rates.

Outer ear infections (OE) affect millions of people annually with significant associated healthcare costs. Incorrect administration or non-compliance with the treatment regimen can lead to infection persistence, recurrence, antibiotic resistance, and in severe cases aggravation to malignant otitis externa. Such issues are particularly pertinent for military personnel, patients in nursing homes, the geriatric population, for patients with head or hand tremors and for those with limited or no access to proper healthcare. With the intent of using traditional material science principles to deconvolute material design while increasing relevance and efficacy, we developed a single application, cold-chain independent thixotropic drug delivery system. This can be easily applied into the ear as a liquid, then gels to deliver effective concentrations of antibiotics against bacterial strains commonly associated with OE. The system maintains thixotropic properties over several stress/no stress cycles, shows negligible swelling and temperature dependence, and does not impact the minimum inhibitory concentration or bactericidal effects of relevant antibiotics. Moreover, the thixogels are biocompatible and are well tolerated in the ear. This drug delivery system can readily translate into a user-friendly product, could improve compliance via a single application by the diagnosing health care provider, is expected to effectively treat OE and minimize the development of antibiotic resistance, infection recurrence or exacerbation.