Titanium dioxide (TiO2) has evolved from a conventional photocatalyst into a sophisticated nano-platform that bridges environmental sustainability and biomedicine. This paper proposes a unified interfacial redox design framework that links the electronic-structure engineering of the TiO2 with the spatial control of its reactive oxygen species (ROS). In the environmental sector, we highlight advances in photocatalytic detoxification, such as the cleavage of organophosphates via Ag-modified TiO2, driven by doping and metal–support interactions. In the biomedical domain, TiO2 is framed as an active bio-interface capable of coordinative protein binding. We specifically examine the “moonlighting” protein dihydrolipoamide dehydrogenase (DLDH) as a model for stable, oriented biofunctionalization. By integrating RGD-targeting motifs, these hybrid systems enable integrin-directed, localized photodynamic effects. We further address critical toxicological considerations, emphasizing that TiO2 behavior is context-dependent and governed by particle size, crystallinity, and surface state. By synthesizing insights from catalysis and redox biology, this manuscript outlines principles for the rational design of safer, application-specific TiO2 technologies. This convergence supports a transition from non-selective oxidation toward predictable, spatially confined redox outcomes in both complex environmental matrices and physiological systems. This review outlines key mechanistic insights and proposes design principles for controlled and context-dependent TiO2 activity.

The traditional catalytic oxidation of carbon monoxide (CO) using metal oxide catalysts often requires either high temperatures (thermocatalysis) or ultraviolet light (UV) excitation (photocatalysis), limiting practical applications under ambient conditions. Our research aimed to develop a catalytic system capable of oxidizing CO to CO2 at room temperature and in the dark. Using the Strong Metal-Support Interaction (SMSI) methodology, several titanium oxide (TiO2)-complexed metals were prepared (Ag, Au, Pd, and Pt). The highest catalytic efficiency of CO oxidation at room temperature was demonstrated for the TiO2-Pt complex. Therefore, this complex was further examined structurally and functionally. Two modes of operation were addressed. The first involved applying the catalytic system to remove CO from an individual's environment (environmental system), while the second involved the installation of the catalysis chamber as a part of a personal protection unit (e.g., a mask). The catalytic activity exhibited a significant reduction in CO levels in both the environmental and personal protection scenarios. The practical application of the system was demonstrated through efficient CO oxidation in air emitted from a controlled fire experiment conducted in collaboration with the Israel Fire and Rescue Authority.

Dihydrolipoamide dehydrogenase (DLDH) is a homodimeric flavin-dependent enzyme that catalyzes the NAD(+)-dependent oxidation of dihydrolipoamide. The enzyme is part of several multi-enzyme complexes such as the Pyruvate Dehydrogenase system that transforms pyruvate into acetyl-co-A. Concomitantly with its redox activity, DLDH produces Reactive Oxygen Species (ROS), which are involved in cellular apoptotic processes. DLDH possesses several moonlighting functions. One of these is the capacity to adhere to metal-oxides surfaces. This was first exemplified by the presence of an exocellular form of the enzyme on the cell-wall surface of Rhodococcus ruber. This capability was evolutionarily conserved and identified in the human, mitochondrial, DLDH. The enzyme was modified with Arg-Gly-Asp (RGD) groups, which enabled its interaction with integrin-rich cancer cells followed by "integrin-assisted-endocytosis." This allowed harnessing the enzyme for cancer therapy. Combining the TiO2-binding property with DLDH's ROS-production, enabled us to develop several medical applications including improving oesseointegration of TiO2-based implants and photodynamic treatment for melanoma. The TiO2-binding sites of both the bacterial and human DLDH's were identified on the proteins' molecules at regions that overlap with the binding site of E3-binding protein (E3BP). This protein is essential in forming the multiunit structure of PDC. Another moonlighting activity of DLDH, which is described in this Review, is its DNA-binding capacity that may affect DNA chelation and shredding leading to apoptotic processes in living cells. The typical ROS-generation by DLDH, which occurs in association with its enzymatic activity and its implications in cancer and apoptotic cell death are also discussed.

Titanium dioxide (TiO2) is a frequently used biomaterial, particularly in orthopedic and dental implants, and it is considered an inert and benign compound. This has resulted in toxicological scrutiny for TiO2 in the past decade, with numerus studies showing potential pathologic downstream effects. Herein we describe case report of a 77-year-old male with subacute CNS dysfunction, secondary to breakdown of a titanium-based carotid stent and leading to blood levels 1000 times higher (3 ppm) than the reported normal. We prospectively collected tissues adjacent to orthopedic implants and found a positive correlation between titanium concentration and time of implant in the body (r = 0.67, p < 0.02). Rats bearing titanium implants or intravascularly treated with TiO2 nanoparticles (TiNP) exhibited memory impairments. A human blood-brain barrier (BBB) in-vitro model exposed to TiNP showed paracellular leakiness, which was corroborated in-vivo with the decrease of key BBB transcripts in isolated blood vessels from hippocampi harvested from TiNP-treated mice. Titanium particles rapidly inter-nalized into brain-like endothelial cells via caveolae-mediated endocytosis and macropinocytosis and induced pro-inflammatory reaction with increased expression of pro-inflammatory genes and proteins. Immune reaction was mediated partially by IL-1R and IL-6. In summary, we show that high levels of titanium accumulate in humans adjacent to orthopedic implants, and our in-vivo and in-vitro studies suggest it may be neurotoxic.

Dihydrolipoamide dehydrogenase (DLDH) is a mitochondrial enzyme that comprises an essential component of the pyruvate dehydrogenase complex. Lines of evidence have shown that many dehydrogenases possess unrelated actions known as moonlightings in addition to their oxidoreductase activity. As part of these activities, we have demonstrated that DLDH binds TiO 2 as well as produces reactive oxygen species (ROS). This ROS production capability was harnessed for cancer therapy via integrin‐mediated drug‐delivery of RGD‐modified DLDH (DLDH RGD ), leading to apoptotic cell death. In these experiments, DLDH RGD not only accumulated in the cytosol but also migrated to the cell nuclei, suggesting a potential DNA‐binding capability of this enzyme. To explore this interaction under cell‐free conditions, we have analyzed DLDH binding to phage lambda (λ) DNA by gel‐shift assays and analytic ultracentrifugation, showing complex formation between the two, which led to full coverage of the DNA molecule with DLDH molecules. DNA binding did not affect DLDH enzymatic activity, indicating that there are neither conformational changes nor active site hindering in DLDH upon DNA‐binding. A Docking algorithm for prediction of protein‐DNA complexes, Paradoc, identified a putative DNA binding site at the C‐terminus of DLDH. Our finding that TiO 2 ‐bound DLDH failed to form a complex with DNA suggests partial overlapping between the two sites. To conclude, DLDH binding to DNA presents a novel moonlight activity which may be used for DNA alkylating in cancer treatment.

The photocatalytic activity of titanium dioxide (TiO2) due to the generation of reactive oxygen species (ROS) under UV excitation is often used for the decontamination of toxic hazardous materials and self-cleaning processes. However, the large band gap of TiO2 limits the activity to the UV region. This limitation can be overcome by metal doping, which results in extending TiO2 activity into the visible range (vis). This paper describes the preparation and characterization of several TiO2 forms and their modifications for enhanced photocatalytic activity in the UV/vis range. In order to advance this concept for environmental decontamination, the degradation of the organophosphorus pesticide and chemical warfare agent, profenofos (PF), was tested. Fast and full degradation of PF was achieved using either TiO2 in the near-UV (365 nm) or Ag-doped TiO2 (TiO2-Ag) in the UV and vis ranges (400-550 nm). The degradation products were identified chromatographically using GC/MS and HPLC, while the detoxification effect was determined electrochemically using an acetylcholinesterase biosensor. In view of our results, we suggest that TiO2-Ag may be implemented as an additive in surface coatings to allow in situ green self-cleaning.

Cancer cells frequently exhibit higher levels of reactive oxygen species (ROS) than normal cells and when ROS levels increase beyond a cellular tolerability threshold, cancer cell death is enhanced. The mitochondrial dihydrolipoamide dehydrogenase (DLDH) is an enzyme which produces ROS in association with its oxidoreductive activity and may be thus utilized as an exogenous anticancer agent. As cancer cells often overexpress integrins that recognize RGD-containing proteins, we have bioengineered the human DLDH with RGD motifs (DLDHRGD) for integrin-mediated drug delivery. The modified protein fully retained its enzyme activity and ROS-production capability. DLDHRGD uptake by cells was shown to depend on the presence of cell-associated integrin αvβ3, as comparatively demonstrated with normal kidney cells (HEK293) transfected with either β1 (αvβ1 positive) or β3 integrins (αvβ3 positive). The interaction with β3 integrins was shown to be competitively inhibited by an RGD peptide. In mice melanoma cells (B16F10), which highly express an endogenous αvβ3 integrin, fast cellular uptake of DLDHRGD which resulted in cell number reduction, apoptosis induction, and a parallel intracellular ROS production was shown. Similar results were obtained with additional human melanoma cell models (A375, WM3314, and WM3682). In contrast, HEK293β3 cells remained intact following DLDHRGD uptake. The high pharmacological safety profile of DLDHRGD has been observed by several modes of administrations in BALB/C or C57Bl/6 mouse strains. Treatments with DLDHRGD in a subcutaneous melanoma mice model resulted in significant tumor inhibition. Our study demonstrated, in vitro and in vivo, the development of a unique platform, which targets cancer cells via integrin-mediated drug delivery of an exogenous ROS-generating drug.

The photocytotoxic effect of UVA-excited titanium dioxide (TiO2), which is caused by the generation of reactive oxygen species (ROS), is often used in medical applications, such as cancer treatment. Photodynamic-therapy (PDT) is applied in several cancer models including cutaneous melanoma (CM), however the lack of selectivity causing damage to surrounding healthy tissues limits its applicability and novel targeted-delivery approaches are required. As cancer cells often overexpress integrin receptors (e.g. αvβ3) on their cell surface, targeted delivery of TiO2 nanoparticles (NPs) via an Arg-Gly-Asp (RGD) motif would make PDT more selective. We have recently reported that the mitochondrial enzyme dihydrolipoamide dehydrogenase (DLDH) strongly and specifically conjugates TiO2via coordinative bonds. In this work we have modified DLDH with RGD moieties (DLDHRGD), creating a molecular bridge between the integrin-expressing cancer cells and the photo-excitable TiO2 nanoparticles. Physicochemical assays have indicated that the hybrid-conjugated nanobiocomplex, TiO2-DLDHRGD, is producing controlled-release ROS under UVA illumination, with anatase NPs being the most photoreactive TiO2 form. This drug delivery system exhibited a cytotoxic effect in αvβ3 integrin-expressing mice melanoma cells (B16F10), but not in normal cells lacking this integrin (HEK293). No cytotoxic effect was observed in the absence of UV illumination. Our results demonstrate the feasibility of combining the high efficiency of TiO2-based PDT, with an integrin-mediated tumor-targeted drug delivery for nanomedicine.

Titanium and its alloys are widely used in dental- and orthopedic implants, the outer surface of which is often oxidized to titanium dioxide (TiO2 ). To achieve efficient osseointegration with bone-forming cells, it is desirable to counter the formation of the soft fibrous tissue around the implant by creating strong and stable interactions between the implant surface and bone-forming osteoblasts. To address this challenge, a bioactive coating had to be designed. Protein adsorption to TiO2 is well known in the literature, but it is mostly characterized by weak associations, rendering less efficient implant osseointegration. We have previously demonstrated the unique conjugation between the dihydrolipoamide dehydrogenase (DLDH) protein and TiO2 surfaces, based on specific coordinative bonding via Cys-His-Glu-Asp motif residues. To enhance cell binding to DLDH and facilitate osseointegration, DLDH was bioengineered to include Arg-Gly-Asp (RGD) moieties (DLDHRGD ). Coating TiO2 disks with DLDHRGD led to improved adherence of integrin-expressing osteogenic MBA-15 to the surface of the disks. Following the enhanced adsorption, higher proliferation rates of the adherent cells, as well as faster mineralization were observed, compared to controls. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 545-551, 2019.

Titanium (Ti) and its alloys are widely used in orthodontic and orthopedic implants by virtue to their high biocompatibility, mechanical strength, and high resistance to corrosion. Biointegration of the implants with the tissue requires strong interactions, which involve biological molecules, proteins in particular, with metal oxide surfaces. An exocellular high-affinity titanium dioxide (TiO2 )-binding protein (TiBP), purified from Rhodococcus ruber, has been previously studied in our lab. This protein was shown to be homologous with the orthologous cytoplasmic rhodococcal dihydrolipoamide dehydrogenase (rhDLDH). We have found that rhDLDH and its human homolog (hDLDH) share the TiO2 -binding capabilities with TiBP. Intrigued by the unique TiO2 -binding properties of hDLDH, we anticipated that it may serve as a molecular bridge between Ti-based medical structures and human tissues. The objective of the current study was to locate the region and the amino acids of the protein that mediate the protein-TiO2 surface interaction. We demonstrated the role of acidic amino acids in the nonelectrostatic enzyme/dioxide interactions at neutral pH. The observation that the interaction of DLDH with various metal oxides is independent of their isoelectric values strengthens this notion. DLDH does not lose its enzymatic activity upon binding to TiO2 , indicating that neither the enzyme undergoes major conformational changes nor the TiO2 binding site is blocked. Docking predictions suggest that both rhDLDH and hDLDH bind TiO2 through similar regions located far from the active site and the dimerization sites. The putative TiO2 -binding regions of both the bacterial and human enzymes were found to contain a CHED (Cys, His, Glu, Asp) motif, which has been shown to participate in metal-binding sites in proteins.

Previously it was shown that a low molecular mass fraction isolated from the proteose-peptone preparation of milk, fraction E, inhibited milk coagulation. Here, the composition and molecular mass of fraction E, and its effect on milk clotting parameters, was investigated to better understand its mechanism of action. Fraction E comprised casein-derived peptides of 1-3 kDa rich in phosphorus residues. Fraction E content increased substantially in milk from glands infected with Escherichia coli and Streptococcus dysgalactiae, and during storage of the milk. However, the specific activity of fraction E on milk clotting parameters was the same whether sampled from healthy, infected or stored milk. The inhibitory effect was reversible on adding 0.75 mM CaCl2, suggesting that chelation of Ca by fraction E was involved in the inhibitory mechanism. However, only partial recovery was achieved and an excess of Ca was required, suggesting the involvement of additional pathways in the process. (C) 2013 Elsevier Ltd. All rights reserved.

: In this work, it is proposed a POCT and innovative method of immunoassay for the detection of C-reactive protein and IgG, using Amperometry coupled to solid state kit, connected to a micro-flow system with comparable sensitivity to a high sensitivity CRP ELISA (hsCRP) and IgG ELISA, with 1-3 min turnaround time to result. Samples of CRP (0 to 250 ng·mL -1 ) and IgG or diluted spiked human serum are injected through a solid state polymeric kit, micro-flow sensor channels of a SWCT SPE nano-modified biosensor. Preparing two kits immuno-assays, in the same micro-column, built on oxirane groups of polymeric bead surface, with biological support to CRP and IgG biomarkers recognition, in a real time scheme, at the end of analyte injection the initial rate of change in current intensity I/A was proportional to CRP respectively IgG concentration, with low detection limit (LOD) of 0.1 ng·mL -1 . It was revealed that CRP/IgG concentrations in serum that might be expected in both normal and pathological conditions can be detected in a real-time-efficient, multi-immunoassay with solid state detection kit technology with determined CRP/IgG concentrations in close agreement with those determined using a commercially available high sensitivity ELISA.

The 19th biennial meeting of the International Society for Molecular Recognition (ISMR), Affinity 2011, was hosted by Professor Guilherme N. M. Ferreira (IBB/UALG) in Tavira, Portugal from June 16th to 19th, 2011. There were 110 registered participants, including 44 students, from 25 countries, in attendance. As stated by the organizers, the main theme of Affinity 2011 centered on “highlights of the scientific advances in molecular binding and recognition through life sciences, bioengineering and nanotechnologies,” with particular focus on aspects of molecular biorecognition related to cell signaling and differentiation, development and application of devices and affinity-based technologies. Despite an economic climate, similar to that experienced at Affinity 2009 in Iceland, Affinity 2011 was received with great success, thanks to the unwavering commitment of Professor Ferreira and his local organizing committee [co-chair Raquel Aires-Barros (IBB/IST), Ana Azevedo (IBB/IST), Cecilia Roque (Requimte/UNL), Joao Goncalves (IMM/FFUL) and DECHEMA (secretariat)]. In the tradition of past Affinity meetings, Affinity 2011 was host to a welcoming reception, the ISMR/Pierce Affinity Award, the Younger Investigator's Award and a gala dinner featuring traditional Portuguese music, Fado, at the Tavira castle. In addition, two “Travel Awards” were kindly sponsored by the Journal of Molecular Recognition (JMR). The scientific program at Affinity 2011 was packed with 41 speakers in nine sessions covering the following topics over 3 days: (1) kinetics and thermodynamics of biomolecular interactions, (2) evolutionary engineering and combinatorial design for affinity and drug discovery, (3) affinity interactions in cell biology – signaling pathways and networks, (4) affinity and protein–protein interactions in health and disease, (5) computational modeling and biomimetic design and materials, (6) affinity-based bioprocessing, (7) nanotechnology, nanomaterials, micro and nanosystems, (8) single-molecule detection: devices/sensors and in vivo tracking and (9) self-assembly and mechanisms of protein machines. Set in Algarve, the southern region of Portugal known for “sunshine breaks and relaxing holidays,” Klaus Mosbach opened Affinity 2011 with a retrospective on “The history of ISMR”. Alois Jungbauer from the Department of Biotechnology at the University of Natural Resources and Life Science in Vienna received the 2011 ISMR/Pierce Affinity Award for his outstanding contributions to the field of “downstream processing.” His lecture entitled “Staphylococcal protein A and camelid antibody affinity chromatography: engineering principles and surface characterization” described the introduction of specific camelid antibodies as an alternative to protein A-based immunoaffinity purification. Two Travel Awards, kindly donated by the Journal of Molecular Recognition, were given to the student, Jennifer D. Knoop from the University of Houston, TX, and the Post-Doc Graziella El Khoury from the University of Cambridge, UK. The Younger Investigators Award sponsored by Hoffmann-La Roche was organized by A. Cecilia Roque and George Ehrlich. Awards were given to nine younger investigators in recognition of their outstanding presentations and active participation at Affinity 2011: Nima Matias Jokilaakso and Johan Nilvebrant (Sweden), Dorota Smolarek (Poland), Matthias Meininger (Germany), Takafumi Honjo (Japan), Alessandro Cumbo (Switzerland) and Luís de Matos Borlido, João Rodrigo Cardoso Trabuco and Telma Barroso (Portugal). The meeting concluded on June 19th with an invitation to the 20th biennial meeting of the International Society for Molecular Recognition in Vienna, Austria, by Affinity 2013 host and organizer, Alois Jungbauer. The 12 peer-reviewed articles published in this special issue span the spectrum of topics presented at Affinity 2011 and cover many profound aspects of affinity-based science and technology. The first section of this volume is devoted to affinity-based technologies and opens with a review article by Maria Raquel Aires-Barrosa's group summarizing strategies for lectin purification. The subsequent article, written by Ranjini and Vijayalakshmi, describes the adsorption of catalase on two mixed mode ligands and discusses the mechanism involved. The next paper by Tekiner et al. describes the use of cryogels for metal-based affinity chromatography for urease purification from jack beans. A similar cryogel was used by Andaç et al., who prepared a new composite protein-imprinted macroporous cryogel for depletion of albumin from human serum prior to use in proteomic applications. Following is a paper by Czarnecka et al., describes the Engineering of Candida albicans glucosamine-6-phosphate synthase by insertion of His6 sequences, a commonly used affinity tag, for efficient enzyme purification. This section concludes with a paper by Sandoval et al., who discuss the use of general rate model to describe elution relationships in affinity chromatography. Two articles by the group of Maria H. L. Ribeiro are related to enzyme immobilization. The first article by Nunesa et al. is entitled “High-affinity water soluble system for efficient naringinase immobilization in polyvinyl alcohol–dimethyl sulfoxide lens-shaped particles.” The, second, by Furtado et al., is entitled “Hesperidinase encapsulation towards hesperitin production targeting improved bioavailability.” The third section deals with the topic of protein–protein interactions. The first article by Kysilka and Vondrašek discusses the analysis of protein–protein interactions in dimeric structures at the molecular level utilizing chemical composition, binding preferences and residue interaction energies, using AMBER empirical force field, in an attempt to reach a better understanding of these interactions in nature. The high-affinity cohesin–dockerin interactions are the topic of the next paper by Slutzki et al., who developed an indirect ELISA-based approach for comparative measurement of these interactions. The dimerization-dependent autophosphorylation, ligand binding and curcumin inhibition of a liposome reconstituted epidermal growth factor receptor are discussed by Doumiati et al. in the next article. The volume concludes with another article from Maria H. L. Ribeiroa's group entitled “Design of selective production of sophorolipids by Rhodotorula bogoriensis through nutritional requirements” by Ribeiroa et al. We wish to thank all the contributors to this volume. We would also like to thank the reviewers who spared either time or effort for shaping and polishing the manuscripts presented in the following pages. Thanks are also due to the editors of the Journal of Molecular Recognition, the Editor-in-Chief, Prof. Marc H. V. Van Regenmortel, and the Executive Commissioning Editor, Dr. Martin Rothlisberger, for the continuing support of the special relationship between the Journal and ISMR and for publishing these proceedings. Special thanks are due to the JMR staff, in particular, Ms Shiela Flores, Ms Faith Pidduck and Ms Rebecca Ralf, who helped us in overcoming difficulties encountered in the editorial work and achieving the final form of this volume. Special thanks are due to Ed Bayer and Meir Wilchek for reviewing, polishing and bettering this article. The ISMR and meeting organizers are grateful to the University of Algarve, the Portuguese Foundation for Science and Technology (FCT), Hoffmann-La Roche and the Journal of Molecular Recognition for their support of Affinity 2011. Thanks are also due to DECHEMA for organizing the Meeting. We look forward to seeing you at Affinity 2013 in Vienna!

Milk-clotting parameters are highly affected by hydrolysis of casein. Previously, it was shown that products of the hydrolysis of casein impair milk clotting, affecting both clotting time and curd firmness. One of these fractions is of particular interest since it is produced exclusively by enzymes of Streptococcus dysgalactiae. The present study aims to further investigate the chemical and structural properties of this fraction in an attempt to understand its influence on milk clotting. Preparations of this fraction, obtained from either S. dysgalactiae-infected glands or ex vivo inoculations with the same bacteria, were found to be identical. Mass spectrometry and Edman degradation analyses indicate that it comprises primarily beta-CN83-209, generated by cleavage at a Val-Val peptide bond, presumably by bacterial thermolysin-or elastin-like proteases. A model offering a putative mechanism for interference with milk-clotting parameters through production of this fraction is presented. (c) 2011 Elsevier Ltd. All rights reserved.

The interactions between titanium oxide (TiO(2)) and flexible peptides, decorated by amine, carboxyl, and phosphoserine functional groups, were characterized using analytical liquid chromatography with various loading and eluting solutions. This approach enabled discernment of the type of intermolecular interactions generated between the peptides and the metal oxide surfaces in addition to unraveling more subtle effects, specific ions, and oxide phase may have on the adsorption. The peptide presenting Lys residues adsorbed to the oxide surface in the presence of Tris buffer and eluted under conditions that indicated its binding via electrostatic interactions at physiological pH values. Upon adsorption to the oxide in the presence of phosphate buffer, the same peptide exhibited stronger electrostatic interactions with the surface, mediated by the buffer phosphate ions. In Tris-buffered saline (TBS), pH 7.4, as the adsorption medium, the peptide with the phosphoserine residues exhibited affinity indicative of coordinative binding to the titanium oxide, whereas a similar peptide decorated by carboxylate groups failed to adsorb. On the basis of differences in the interactions of these peptides with the TiO(2), the efficient separation of the two peptides was demonstrated. A basic amphiphilic peptide, composed mostly of Lys and Leu residues, was found to strongly adsorb to TiO(2) while in helical conformation only, demonstrating the strong impact the secondary structure may have on adsorption to the surface. The methodology presented in this study allows the elucidation of in situ binding mechanism and relative strengths to titanium oxide surfaces at conditions which resemble biologically relevant environments.

5 The 17th biennial meeting of the International Society for Molecular Recognition (ISMR) took place on 8–12 July 2007 in New York City and was attended by over 100 scientists from academia, industry, and government from 15 countries of five continents. New York University hosted the meeting in Greenwich Village, which is renowned as a hub for new ideas, progressive movements, and higher education. The idea to host Affinity 2007 in New York City was suggested by the journal’s founding editor, Irwin Chaiken, in Cambridge, England at Affinity 2003. The Affinity 2007/NYC proposal that followed was approved shortly thereafter and the stage was set, thanks to Affinity 2005 organizer, Lars Hagel, in Uppsala, Sweden. Building on the Affinity 2005 model and recommendations from the ISMR Council, International Scientific Advisory Board, and Local Organizing Committee, a consensus-based working plan was proposed in Summer/Fall 2006. The program that followed was one steeped in the traditions of ‘‘Affinity past’’ with a particular focus on ‘‘Affinity future.’’ Toward this end, the final program included an inaugural lecture/ reception, scientific sessions featuring several prominent keynote speakers, contributed oral and poster presentations, exhibits, the Pierce Affinity Award, the Roche Younger Investigators Award, a Gala dinner, and other ‘‘social interactions.’’ The session topics, talks, and chairs for Affinity 2007 were carefully selected to create a balance between basic and applied research in Affinity technology and science. Mathias Uhlén’s welcoming lecture on the Human Protein Atlas was the perfect example set in the Rosenthal Pavilion overlooking Washington Square Park in the ‘‘original corner of cool.’’ The first session of Affinity 2007 chaired by Mathias, was aptly named, ‘‘Affinity: Past, Present and Future.’’ Lars Hagel chaired the second session entitled, ‘‘Advances in Affinity Technologies.’’ The third session, ‘‘New Developments in Chromatography’’ was chaired by Juan Asenjo. Richard Willson was chair to the fourth session on ‘‘Nano/Bio/Materials.’’ The fifth session, ‘‘Insights into Intraand Intermolecular Interactions,’’ was chaired by M.A. ‘‘Viji’’ Vijayalakshmi. Irwin Chaiken presided over the sixth session entitled, ‘‘Protein Interactions In and On Cells.’’ The seventh session, ‘‘Viruses and Vaccines,’’ was chaired by Daniel Malamud, and the final session on ‘‘Drug Discovery and Diagnostics’’ was chaired by Hitesh Chokshi. Among the highlights from these sessions were plenary lectures from three National Academy of Science members: Meir Wilchek, who kicked off the opening session with his talk entitled, ‘‘My Life with Affinity: Essentials of Biorecognition and Its Application,’’ Wayne Hendrickson, who lectured on ‘‘Ligand Recognition and Plasticity in HIV Envelope Glycoprotein gp120,’’ and Ron Breslow, who closed the last session with a lecture

Rhodococcus ruber GIN1 (formally Rh. strain GIN1) was previously isolated on the basis of its strong adherence to coal fly ash (CFA) and titanium dioxide particles from CFA sedimentation ponds of an electrical power plant in Israel. The interaction of the bacterium with oxides has been shown to be mediated by a cell surface protein designated TiBP (titanium binding protein) involving primarily strong, non-electrostatic forces. In this work, we set forward to identify this unique exocellular protein. Sequence analysis of the purified protein by mass spectrometry (LC/MS/MS) following trypsinization revealed 11 peptides. All of them showed >90% amino acid residues identity with sequences of one of the orthologs (dldh1) of the cytosolic enzyme dihydrolipoamide dehydrogenase (DLDH), based on the genome sequence of Rhodococcus strain RHA1. This genome was selected as a reference since currently it is the only sequenced Rhodococcal genome. Altogether, these peptides covered over 25% of the 52 kDa protein molecule. N- and C-termini primers were prepared and used to sequence the paralog gene from Rh. ruber GIN1 after polymerase chain reaction (PCR) amplification. All 11 peptides showed 100% identity with the sequence of this gene. The homology of TiBP with the supposedly cytosolic DLDH raised the question of whether the exocellular TiBP possesses DLDH activity. Indeed, intact late logarithmic phase Rh. ruber GIN1 cells, previously shown to express TiBP, were found to possess such activity, while very low activity was associated with stationary phase cells which possess diminished TiBP expression on their surface. Further evidence for the exocellular location of TiBP/DLDH was achieved using specific anti-TiBP polyclonal antibodies by whole cell and protein enzyme-linked immunosorbent assay (ELISA), showing high reactivity of the logarithmic phase cell surface and substantially lower reactivity with the stationary phase cells. As expected, logarithmic phase spheroplasts were not recognized by these antibodies. Similar results were obtained by fluorescence and scanning electron microscopy. Our postulation that DLDH is located on the surface of Rh. ruber GIN1, serving as a TiO2 binding protein, is in accordance with literary evidence on DLDH in other organisms, Bacteria, Archea, and Eukaryots that suggests it is associated with the outer membranes or cell surfaces. As an exocellular protein DLDH assumes various tasks which are not related to its classical role as a 2-oxoacid dehydrogenase, including serving as an adhesion/binding protein in certain bacteria.

Subclinical mastitis, caused by different bacteria with similar milk composition and somatic cell count, impairs milk quality and its products differently through increased release of deteriorative enzymes into the milk. Milk from glands infected with Streptococcus dysgalactiae was almost identical in gross composition to milk from uninfected glands. However, yogurt and cheese made from commingled milk from the infected quarters exhibited inferior texture compared to yogurt and cheese made from uninfected ones. Proteose peptone was size-fractionated by gel filtration and the various fractions of milk from the infected glands were added to uninfected milk. This study demonstrated for the first time that addition of certain fractions to milk from uninfected glands resulted in altered milk coagulation properties. It is hypothesized that the infecting bacteria influence the immune system of the udder, which then impairs the qualities of the milk from infected quarters that is conventionally used for manufacturing dairy products.