Hydroxyethylcellulose as a methotrexate carrier in anticancer therapy.

Clinical and experimental cancer therapy is multifaceted; one such facet is the use of drug carriers. Drug carriers are various nano- and macromolecules, e.g., oligosaccharides, proteins, and liposomes. The present study aimed to verify the suitability of cellulose as a carrier for methotrexate (MTX). Hydroxyethylcellulose, with a molecular weight of 90 kDa and soluble in water, was used. Methotrexate was linked to cellulose by methyl ester bonds. A conjugate containing on average 9.5 molecules of MTX per molecule of cellulose was developed. Gel filtration HPLC analysis showed that the conjugate contained approximately 2% free drug. Dynamic light scattering analysis showed an increase in the polydispersity of the conjugate. The degradation of the conjugate in phosphate buffer and plasma followed first-order kinetics. The conjugate showed the lowest stability (half-life 154 h) in plasma. The conjugate showed 10-fold lower cytotoxicity to the 4 T1 mammary tumour cell line than the free drug. In the in vivo experiment to treat orthotopically implanted mammary tumours, the conjugate and the free drug, both applied intravenously, showed maximum inhibition of tumour growth of 48.4% and 11.2%, respectively. In conclusion, cellulose, which is a non-biodegradable chain glucose polymer, can be successfully used as a drug carrier, which opens up new research perspectives.

Synthesis and Biological Activity of Thymosin ß4-Anionic Boron Cluster Conjugates.

Anionic boron clusters are man-made, inorganic compounds with potential applications in therapeutic peptides modification to improve their biological activity and pharmacokinetics, e.g., by enabling complexation with serum albumin. However, the conjugation of anionic boron clusters and peptides remains poorly understood. Here, we report a solid-state, thermal reaction to selectively conjugate carboxylic groups in the peptide thymosin ß4 (Tß4) with cyclic oxonium derivatives of anionic boron clusters (dodecaborate anion [B12H12]2- and cobalt bis(1,2-dicarbollide), [COSAN]- [3,3'-Co(1,2-C2B9H11)2]-). Modification of the carboxylic groups retains the negative charge at the modification site and leads to the formation of ester bonds. The ester bonds in the conjugates undergo hydrolysis at different rates depending on the site of the modification. We obtained conjugates with dramatically different stabilities (τ1/2 from 3-836 h (Tß4-[B12H12]2- conjugates) and 9-1329 h (Tß4-[COSAN]- conjugates)) while retaining or improving the prosurvival activity of Tß4 toward cardiomyocytes (H9C2 cell line).

Aggregation/dispersion transitions of T4 phage triggered by environmental ion availability.

BACKGROUND: Bacteriophage survives in at least two extremes of ionic environments: bacterial host (high ionic-cytosol) and that of soil (low ionic-environmental water). The impact of ionic composition in the micro- and macro-environments has not so far been addressed in phage biology. RESULTS: Here, we discovered a novel mechanism of aggregation/disaggregation transitions by phage virions. When normal sodium levels in phage media (150 mM) were lowered to 10 mM, advanced imaging by scanning electron microscopy, atomic force microscopy and dynamic light scattering all revealed formation of viral packages, each containing 20-100 virions. When ionic strength was returned from low to high, the aggregated state of phage reversed to a dispersed state, and the change in ionic strength did not substantially affect infectivity of the phage. By providing the direct evidence, that lowering of the sodium ion below the threshold of 20 mM causes rapid aggregation of phage while returning Na+ concentration to the values above this threshold causes dispersion of phage, we identified a biophysical mechanism of phage aggregation. CONCLUSIONS: Our results implicate operation of group behavior in phage and suggest a new kind of quorum sensing among its virions that is mediated by ions. Loss of ionic strength may act as a trigger in an evolutionary mechanism to improve the survival of bacteriophage by stimulating aggregation of phage when outside a bacterial host. Reversal of phage aggregation is also a promising breakthrough in biotechnological applications, since we demonstrated here the ability to retain viable virion aggregates on standard micro-filters.

Synthesis of ß-cyclodextrin-lysozyme conjugates and their physicochemical and biochemical properties.

Recently a great interest in the field of protein engineering and the design of innovative drug delivery systems employing specific ligands such as cyclodextrins is observed. The paper reports the solid state, thermal method for protein coupling with ß-cyclodextrin and the physicochemical and biological properties of the obtained conjugates. The structure of the obtained conjugates was investigated via liquid chromatography-mass spectrometry, dynamic light scattering and circular dichroism analysis. The presented conjugates were biologically active and covalently bound ß-cyclodextrin preserved the ability to form inclusion complexes with the model compound. This report demonstrates the great potential of cyclodextrin as a modifying unit that can be used to modulate the properties of therapeutic proteins, additionally giving such conjugates the possibility to transport many therapeutic substances in the form of inclusion complexes. In addition, the paper presents the potential of protein-cyclodextrin conjugates to construct innovative bioactive molecules for biological and medical applications.

Methotrexate and epirubicin conjugates as potential antitumor drugs.

INTRODUCTION: The use of hybrid molecules has become one of the most significant approaches in new cytotoxic drug design. This study describes synthesis and characterization of conjugates consisting of two well-known and characterized chemotherapeutic agents: methotrexate (MTX) and epirubicin (EPR). The synthesized conjugates combine two significant anticancer strategies: combinatory therapy and targeted therapy. These two drugs were chosen because they have different mechanisms of action, which can increase the anticancer effect of the obtained conjugates. MTX, which is a folic acid analog, has high cytotoxic properties and can serve as a targeting moiety that can reach folate receptors (FRs) overexpresing tumor cells. Combination of nonselective drugs such as EPR with MTX can increase the selectivity of the obtained conjugates, while maintaining the high cytotoxic properties. MATERIALS AND METHODS: Conjugates were purified by RP-HPLC and the structure was investigated by MS and MS/MS methods. The effect of the conjugates on proliferation of LoVo, LoVo/Dx, MCF-7 and MV-4-11 human cancer cell lines was determined by SRB or MTT assay. RESULTS: The conjugation reaction results in the formation of monosubstituted (α, γ) and disubstituted MTX derivatives. In vitro proliferation data demonstrate that the conjugates synthesized in our study show lower cytotoxic properties than both chemotherapeutics used alone. DISCUSSION: Epirubicin cytotoxicity was not observed in obtained conjugates. Effective drugs release after internalization needs further investigation.

Solid state, thermal synthesis of site-specific protein-boron cluster conjugates and their physicochemical and biochemical properties.

BACKGROUND: Boron clusters represent a vast family of boron-rich compounds with extraordinary properties that provide the opportunity of exploitation in different areas of chemistry and biology. In addition, boron clusters are clinically used in boron neutron capture therapy (BNCT) of tumors. In this paper, a novel, in solid state (solvent free), thermal method for protein modification with boron clusters has been proposed. METHODS: The method is based on a cyclic ether ring opening in oxonium adduct of cyclic ether and a boron cluster with nucleophilic centers of the protein. Lysozyme was used as the model protein, and the physicochemical and biological properties of the obtained conjugates were characterized. RESULTS: The main residues of modification were identified as arginine-128 and threonine-51. No significant changes in the secondary or tertiary structures of the protein after tethering of the boron cluster were found using mass spectrometry and circular dichroism measurements. However, some changes in the intermolecular interactions and hydrodynamic and catalytic properties were observed. CONCLUSIONS: To the best of our knowledge, we have described the first example of an application of cyclic ether ring opening in the oxonium adducts of a boron cluster for protein modification. In addition, a distinctive feature of the proposed approach is performing the reaction in solid state and at elevated temperature. GENERAL SIGNIFICANCE: The proposed methodology provides a new route to protein modification with boron clusters and extends the range of innovative molecules available for biological and medical testing.

Bacteriophages to combat foodborne infections caused by food contamination by bacteria of the Campylobacter genus.

It is estimated that each year more than 2 million people suffer from diarrheal diseases, resulting from the consumption of contaminated meat. Foodborne infections are most frequently caused by small Gram-negative rods Campylobacter. The hosts of these bacteria are mainly birds wherein they are part of the normal intestinal flora. During the commercial slaughter, there is a likelihood of contamination of carcasses by the bacteria found in the intestinal content. In Europe, up to 90% of poultry flocks can be a reservoir of the pathogen. According to the European Food Safety Authority report from 2015, the number of reported and confirmed cases of human campylobacteriosis exceeds 200 thousands per year, and such trend remains at constant level for several years. The occurrence of growing antibiotic resistance in bacteria forces the limitation of antibiotic use in the animal production. Therefore, the European Union allows only using stringent preventive and hygienic treatment on farms. Achieving Campylobacter free chickens using these methods is possible, but difficult to implement and expensive. Utilization of bacterial viruses - bacteriophages, can be a path to provide the hygienic conditions of poultry production and food processing. Formulations applied in the food protection should contain strictly lytic bacteriophages, be non-pyrogenic and retain long lasting biological activity. Currently, on the market there are available commercial bacteriophage preparations for agricultural use, but neither includes phages against Campylobacter. However, papers on the application of bacteriophages against Campylobacter in chickens and poultry products were published in the last few years. In accordance with the estimates, 2-logarithm reduction of Campylobacter in poultry carcases will contribute to the 30-fold reduction in the incidence of campylobacteriosis in humans. Research on bacteriophages against Campylobacter have cognitive and economic importance. The paper presents current state of research on bacteriophages targeted against Campylobacter.

Synthesis of lysozyme-metallacarborane conjugates and the effect of boron cluster modification on protein structure and function.

Two complementary methods, "in solution" and "in solid state", for the synthesis of lysozyme modified with metallacarborane (cobalt bis(dicarbollide), Co(C2 B9 H11 )2 (2-) ) were developed. As metallacarborane donors, oxonium adducts of cobalt bis(dicarbollide) and 1,4-dioxane or tetrahydropyran were used. The physicochemical and biochemical properties of the obtained lysozyme-metallacarborane conjugates were studied for changes in secondary and tertiary structure, aggregation behavior, and biological activity. Only minor changes in primary, secondary, and tertiary protein structure were observed, caused by the single substitution of metallacarborane on lysozyme. However, the modification produced significant changes in lysozyme enzymatic activity and a tendency toward time- and temperature-dependent aggregation.

Applying the prodrug strategy to α-phosphonocarboxylate inhibitors of Rab GGTase--synthesis and stability studies.

Fourteen novel prodrug-like analogs of two highly ionic phosphonocarboxylate inhibitors of Rab geranylgeranyl transferase were synthesized and preliminary assessment of their chemical and enzymatic stability was evaluated in buffers (pH 6.5 and 7.4) and rat intestinal homogenate (pH 6.5). Both acidic groups in phosphonocarboxylates were subject to modification. Phosphonic acid was protected either as bis(acyloxyalkyl) ester or phosphonodiamidate derived from amino acids. The carboxylic acid group was either left unchanged or was studied as ethyl ester. The compounds exhibited favorable stability in physiologically relevant pH (t1/2 above 18 h), while in intestinal homogenate they showed a large variety of half-lives (from 5 minutes to over 150 hours). LC MS studies have shown that the main product of decomposition under studied conditions resulted from cleavage of one of the ester (for acyloxyalkyl analogs) or amide (for phosphonodiamidate) bonds with phosphorus.

The antileukemic activity of modified fibrinogen-methotrexate conjugate.

BACKGROUND: The search for new, innovative methods to treat all types of diseases, especially cancer-related ones, is a challenge taken by pharmaceutical companies and academic institutions. The use of conjugates containing widely-known and widely-used bioactive substances is one of the ways to solve this problem. Research into drug binding with macromolecular carrier systems has joined the search for new therapeutic strategies. METHODS: The main goal of this paper is the potential offered by the use of fibrinogen derivatives as an antileukemic drug carrier. Physicochemical properties of the obtained conjugate were analyzed, characterizing alterations in relation to the starting carrier and analyzing biological implications. The intraperitoneally (i.p.) inoculated P388 mouse leukemia model for in vivo studies was used. RESULTS AND CONCLUSIONS: Conjugates consisting of a fibrinogen derivative with a covalently bound anticancer drug were developed. Carrier preparation and a conjugate synthesis in aqueous solution were formulated, as well as purification of the conjugate was performed. The study showed that the survival of leukemia mice treated with FH-MTX conjugate was indeed significantly longer than survival in both untreated animals (control) and mice treated with unbound MTX. A significant increase in the antileukemic activity of MTX conjugated with hydrolysed fibrinogen was observed as compared with the unconjugated drug. Reported data suggest that hydrolysed fibrinogen can serve as a carrier molecule for the MTX drug with the aim of enhancing its antileukemic activity. GENERAL SIGNIFICANCE: Conjugates consisting of a fibrinogen derivative with a covalently bound anticancer drug seem to be a promising anticancer drug.

[Noncovalent cation-π interactions--their role in nature]. / Oddzialywania niekowalencyjne kation-π­ich rola w przyrodzie

Non-covalent interactions play an extremely important role in organisms. The main non-covalent interactions in nature are: ion-ion interactions, dipole-dipole interactions, hydrogen bonds, and van der Waals interactions. A new kind of intermolecular interactions--cation-π interactions--is gaining increasing attention. These interactions occur between a cation and a π system. The main contributors to cation-π interactions are electrostatic, polarization and, to a lesser extent, dispersion interactions. At first, cation-π interactions were studied in a gas phase, with metal cation-aromatic system complexes. The characteristics of these complexes are as follows: an increase of cation atomic number leads to a decrease of interaction energy, and an increase of cation charge leads to an increase of interaction energy. Aromatic amino acids bind with metal cations mainly through interactions with their main chain. Nevertheless, cation-π interaction with a hydrophobic side chain significantly enhances binding energy. In water solutions most cations preferentially interact with water molecules rather than aromatic systems. Cation-π interactions occur in environments with lower accessibility to a polar solvent. Cation-π interactions can have a stabilizing role on the secondary, tertiary and quaternary structure of proteins. These interactions play an important role in substrate or ligand binding sites in many proteins, which should be taken into consideration when the screening of effective inhibitors for these proteins is carried out. Cation-π interactions are abundant and play an important role in many biological processes.

[Mycolic acids--biological role and potential application in Mycobacterium detection and differentiation]. / Kwasy mikolowe--rola biologiczna i potencjalne zastosowanie w wykrywaniu oraz róznicowaniu rodzaju Mycobacterium.

Mycolic acids are one of the basic structural elements of the cell wall of bacteria from Corynebacterineae suborder. These compounds are long-chain α-hydroxy ß-alkyl fatty acids with two hydrocarbon chains: longer meromycolic and shorter α-chain meromycolic α-chain. The genus Mycobacterium is characterized by the presence of mycolic acids in length from 60 to 90 carbon atoms having a fully saturated α-chain with a defined length of 22, 24 or 26 carbon atoms. Current research indicates that not only the presence of mycolic acids in the cell wall of mycobacteria is essential for the virulence of mycobacteria. It is proved that the relationship between different types of mycolic acids, their length and the degree of cyclopropanation may vary depending on the stage of infection and mycobacterial culture conditions. At the same time it has been shown that some mycolic acid types are crucial for biofilm formation, antimycobacterial drug resistance or interactions with the immune system. Recent studies also indicate that analysis of mycolic acid profiles could be an alternative to conventional methods of diagnosis of diseases such as tuberculosis, leprosy or mycobacteriosis.

Comparison of microbiological and physicochemical methods for enumeration of microorganisms.

Determination of the number of cultured bacteria is essential for scientific and industrial practice. A spread plate technique is the most common and accurate method for counting of microorganisms. However, time consuming incubation does not allow for a quick estimation of the number of bacteria in a growing culture. In the present study, the results of photometric measurements: direct optical density method (OD at 585 nm), UV absorbance at 260 and/or 280 nm of separated and lysed bacteria by sodium hydroxide and surfactant with the spread plate technique were compared. The linear regression model for bacterial strains Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli was used to compare these three methods. The UV measurement method enabled determination of the number of bacteria with similar precision. The procedure for solubilized bacteria UV measurement is robust, and is not influenced by dispersions in the original culture medium.

Could the lake ecosystems influence the pathogenicity of the SARS-COV-2 in the air?

During the first 200 days of the Covid-19 pandemic in Poland, lower morbidity and mortality due to SARS-COV-2 infection were recorded in three regions covered by many small and large lakes (West Pomerania 5.8 deaths/100 000 population, Warmian and Masurian 7.6 deaths/100 000 population, Lubusz 7.3 deaths /100 000 population, compared to Poland average of 16.0 deaths/100 000 population). Moreover, in Mecklenburg (Germany), bordering West Pomerania, only 23 deaths (1.4 deaths/100 000 population) were reported during the same period (Germany 10 649 deaths, 12.6 deaths/100 000 population). This unexpected and intriguing observation would not have been noticed if SARS-CoV-2 vaccinations were available at that time. The hypothesis presented here assumes the biosynthesis of biologically active substances by phytoplankton, zooplankton or fungi and transfer of these lectin-like substances to the atmosphere, where they could cause agglutination and/or inactivation of pathogens through supramolecular interactions with viral oligosaccharides. According to the presented reasoning, the low mortality rate due to SARS-CoV-2 infection in Southeast Asian countries (Vietnam, Bangladesh, Thailand) could be explained by the influence of monsoons and flooded rice fields on microbiological processes in the environment. Considering the universality of the hypothesis, it is important whether the pathogenic nano- or micro particles are decorated by oligosaccharides (as in case of the African swine fever virus, ASFV). On the other hand, the interaction of influenza hemagglutinins with sialic acid derivatives biosynthesized in the environment during the warm season may be linked to seasonal fluctuations in the number of infections. The presented hypothesis may be an incentive to study unknown active substances in the environment by interdisciplinary teams of chemists, physicians, biologists, and climatologists.

[The role of metalloproteinases in modification of extracellular matrix in invasive tumor growth, metastasis and angiogenesis]. / Rola metaloproteinaz w modyfikacji macierzy zewnatrzkomórkowej w nowotworowym wzroscie inwazyjnym, w przerzutowaniu i w angiogenezie.

Extracellular matrix metalloproteinases (MMPs) are a family of endopeptydases which recquire a zinc ion at their active site, for proteolityc activity. There are six members of the MMP family: matrilysins, collagenases, stromelysins, gelatinases, membrane MMPs and other MMPs. Activity of MMPs is regulated at the level of gene transcription, mRNA stability, zymogene proteolitic activation, inhibition of an active enzyme and MMP degradation. Tissue inhibitors of metalloproteinases (TIMPs) are main intracellular inhibitors of MMPs. Host cells can be stimulated by tumor cells to produce MMPs by secreted interleukins, interferons, growth factors and an extracellular matrix metalloproteinase inducer (EMMPRIN). MMPs are produced by tumor cells, fibroblasts, macrophages, mast cells, polimorphonuclear neutrophiles (PMNs) and endothelial cells (ECs). MMPs affect many stages of tumor development, facilitating its growth through promoting tumor cells proliferation, invasion and migration, new blood vessels formation and blocking tumor cells apoptosis. MMPs can promote tumor development in several ways. ECM degradation results in release of peptide growth factors. Growth factors linked with cell surface or binding proteins can also be liberated by MMPs. MMPs can indirectly regulate integrin signalling or cleave E-cadherins, facilitating cell migration. MMPs support metastasis inducing an epithelial to mesenchymal transition (EMT). MMP also support transendothelial migration. MMPs support angiogenesis by releasing pro-angiogenic factors and degrading ECM to support ECs migration. Cell surface growth factor receptors are also cleaved by MMPs, which results in inhibition of tumor development, so is release of anti-angiogenic factors from ECM. 

[Osmoregulation--an important parameter of bacterial growth]. / Osmoregulacja--wazny parametr rozwoju bakterii.

Environmental conditions such as temperature, pH, radiation and osmotic pressure are important factors limiting the growth and multiplication of bacteria. Regular structure and metabolism of bacterial cells are maintained through a stable arrangement of the water-electrolyte system, regulated by osmosis. The rapid changes caused by osmotic shock (dehydration, rehydration) might lead to modifications of the phospholipid structure of the cell membrane and even cell death. Advances disturbing the osmosis, which are a natural part of living cells, may appear for example in colloid systems. The biological identification of the osmotic pressure is connected with an increase or decrease in the environmental osmotic strength of microorganisms' habitat. Cells exposed to osmotic stress, such as an increase in osmotic pressure, initiate mechanisms of active coping with the adverse consequences of its effects. Osmoregulatory processes are designed to maintain cell turgor, hence ensuring proper conditions for bacterial growth. Osmoregulation, which consists of maintaining fluid and electrolyte balance of cells, raising concerns accumulation of specific compatible solutes (osmolytes). Osmolytes are small, soluble organic molecules with a positive influence on membrane stabilization and proteins, without disrupting cellular functions. Storage of compatible solutes takes place by synthesis or by downregulation from the medium by means of special transport systems, activated by mechanical stimuli. Knowledge of the impact of osmotic pressure on microbial cells and the regulation of its activity led to the appropriate use of bacteria in various branches of the biotechnology industry.

Boron-Rich Boron Carbide Nanoparticles as a Carrier in Boron Neutron Capture Therapy: Their Influence on Tumor and Immune Phagocytic Cells.

The aim of the work was to study the interaction between boron-rich boron carbide nanoparticles and selected tumor and immune phagocytic cells. Experiments were performed to investigate the feasibility of the application of boron carbide nanoparticles as a boron carrier in boron neutron capture therapy. Boron carbide powder was prepared by the direct reaction between boron and soot using the transport of reagents through the gas phase. The powder was ground, and a population of nanoparticles with an average particle size about 80 nm was selected by centrifugation. The aqueous suspension of the nanoparticles was functionalized with human immunoglobulins or FITC-labeled human immunoglobulins and was then added to the MC38 murine colon carcinoma and to the RAW 264.7 cell line of mouse macrophages. Flow cytometry analysis was used to determine interactions between the functionalized boron carbide nanoparticles and respective cells. It was shown that B4C-IgG nanoconjugates may bind to phagocytic cells to be internalized by them, at least partially, whereas such nanoconjugates can only slightly interact with molecules on the cancer cells' surface.

De­O­acylated lipooligosaccharide of E. coli B reduces the number of metastatic foci via downregulation of myeloid cell activity.

Lipopolysaccharides are the main surface antigens and virulence factors of gram­negative bacteria. Removal of four ester­bound fatty acid residues from hexaacyl lipid A of Escherichia coli lipooligosaccharide (LOS) resulted in the de­O­acylated derivative E. coli LOS­OH (LOS­OH). This procedure caused a significant reduction in the toxicity of this compound compared to the native molecule. We investigated the effect of such a structural LOS modification on its biological activity using in vitro assays with monocytic cells of the RAW264.7 line, dendritic cells of the JAWS II line, bone marrow­derived dendritic cells (BM­DCs), and spleen cells. Furthermore, in in vivo experiments with a melanoma B16 metastasis model, the anti­metastatic activity of the compounds and spleen cell reactivity mediated by them representing a systemic response were analyzed. The results revealed that LOS­OH demonstrated weaker ability than LOS to stimulate and polarize an immune response both in vitro and in vivo. It induced lower cytokine production by cells of myeloid lines. Multiple applications of LOS­OH into mice injected intravenously with B16 cells significantly (P<0.05; P<0.01) reduced the number of metastatic foci in the lungs, presumably via silencing of myeloid cell reactivity as well as the inability to stimulate lymphoid cells both directly and indirectly. These findings suggest that LOS­OH maintained in the body of metastasis­bearing mice appears to modulate or downregulate the innate response, leading to the inability of blood myeloid cells to support the migration of melanoma cells to lung tissue.

The effect of bacteriophages T4 and HAP1 on in vitro melanoma migration.

BACKGROUND: The antibacterial activity of bacteriophages has been described rather well. However, knowledge about the direct interactions of bacteriophages with mammalian organisms and their other, i.e. non-antibacterial, activities in mammalian systems is quite scarce. It must be emphasised that bacteriophages are natural parasites of bacteria, which in turn are parasites or symbionts of mammals (including humans). Bacteriophages are constantly present in mammalian bodies and the environment in great amounts. On the other hand, the perspective of the possible use of bacteriophage preparations for antibacterial therapies in cancer patients generates a substantial need to investigate the effects of phages on cancer processes. RESULTS: In these studies the migration of human and mouse melanoma on fibronectin was inhibited by purified T4 and HAP1 bacteriophage preparations. The migration of human melanoma was also inhibited by the HAP1 phage preparation on matrigel. No response of either melanoma cell line to lipopolysaccharide was observed. Therefore the effect of the phage preparations cannot be attributed to lipopolysaccharide. No differences in the effects of T4 and HAP1 on melanoma migration were observed. CONCLUSION: We believe that these observations are of importance for any further attempts to use bacteriophage preparations in antibacterial treatment. The risk of antibiotic-resistant hospital infections strongly affects cancer patients and these results suggest the possibility of beneficial phage treatment. We also believe that they will contribute to the general understanding of bacteriophage biology, as bacteriophages, extremely ubiquitous entities, are in permanent contact with human organisms.

Metallacarboranes as a tool for enhancing the activity of therapeutic peptides.

Metallacarboranes are anionic boron clusters with high affinity to serum albumin, ability to cross biological membranes, and no apparent toxicity in vitro and in vivo. Thus, conjugation with cobalt bis(1,2-dicarbollide), [COSAN]- , ([3,3'-Co(1,2-C2 B9 H11 )2 ]- ) may improve the properties of therapeutic peptides or proteins at both molecular and systemic levels. Here, we conjugated [COSAN]- with the therapeutic peptide thymosin ß4 (Tß4), which has a pleiotropic activity that results in enhanced healing and regeneration of injured tissues. Using fluorescence quenching of human serum albumin and surface plasmon resonance techniques, we showed that the conjugates have a high affinity to human serum albumin. Using an in vitro wound closure assay, we showed that conjugation with [COSAN]- enhances the activity of Tß4 toward fibroblasts (MSU1.1 cell line). These results indicate an application of metallacarboranes in the development of analogs of various therapeutic peptides/proteins with superior pharmacological properties.