Correction to: pH control and the production of extracellular dextransucrase by Leuconostoc mesenteroides.

Unfortunately, M. M. Vrvic name has been published incorrectly in the original publication as M. M. Vrivic, corrected name appears in this erratum.

Ultrasound-assisted adsorption of 4-dodecylbenzene sulfonate from aqueous solutions by corn cob activated carbon.

This study was aimed at removal of 4-dodecylbenzene sulfonate (DBS) ions from aqueous solutions by ultrasound-assisted adsorption onto the carbonized corn cob (AC). The main attention was focused on modeling the equilibrium and kinetics of adsorption of DBS onto the AC. The AC was prepared from ground dried corn cob by carbonization and activation by carbon dioxide at 880°C for 2h in a rotary furnace. The adsorption isotherm data were fitted by the Langmuir model in both the absence and the presence of ultrasound (US). The maximum adsorption capacities of the adsorbent for DBS, calculated from the Langmuir isotherms, were 29.41mg/g and 27.78mg/g in the presence of US and its absence, respectively. The adsorption process in the absence and the presence of US obeyed the pseudo second-order kinetics. The intraparticular diffusion model indicated that the adsorption of DBS ions on the AC was diffusion controlled as well as that US promoted intraparticular diffusion. The ΔG° values, -24.03kJ/mol, -25.78kJ/mol and -27.78kJ/mol, were negative at all operating temperatures, verifying that the adsorption of DBS ions was spontaneous and thermodynamically favorable. The positive value of ΔS°=187J/molK indicated the increased randomness at the adsorbent-adsorbate interface during the adsorption of DBS ions by the AC.

Aerobic exercise training as a potential source of natural antibodies protective against human immunodeficiency virus-1.

Despite the effectiveness of HAART in controlling HIV-1 replication, the emergence of drug-resistant viruses in infected patients and the severe side effects caused by the currently used drug regimens and the lack of an effective vaccine necessitate the continued search for new therapeutic strategies for prevention and therapy of HIV disease. Previously we reported that natural autoantibodies, recognizing peptide FTDNAKTI (peptide NTM1) derived from the C2 domain of HIV-1 gp120, contribute to the control of HIV disease. Here we demonstrated that sera from well-trained athletic (HIV-negative) subjects showed high reactivity with peptide NTM1. This result confirms that aerobic exercise training stimulates production of natural autoantibodies, which recognize peptide NTM1. Bioinformatics analysis indicates that these natural autoantibodies could slow down disease progression by blocking the superantigenic site on HIV-1 gp120. The results suggest that aerobic exercise training may be a promising non-toxic and inexpensive adjunctive anti-HIV therapy.

Ultrasound-assisted adsorption of copper(II) ions on hazelnut shell activated carbon.

The present study was aimed to removal of Cu(II) ions from aqueous solution by ultrasound-assisted adsorption onto the granular activated carbon obtained from hazelnut shells. The attention was focused on modeling the equilibrium and kinetics of Cu(II) adsorption onto the granular activated carbon. The granular activated carbon was prepared from ground dried hazelnut shells by simultaneous carbonization and activation by water steam at 950 degrees C for 2h. Adsorption isotherm data were better fitted by the Langmuir model than the Freundlich model in both the absence and the presence of ultrasound. The maximum adsorption capacity of the adsorbent for Cu(II), calculated from the Langmuir isotherms, in the presence of ultrasound (3.77 mmol/g) is greater than that in the absence of ultrasound (3.14 mmol/g). The adsorption process in the absence and the presence of ultrasound obeyed to the pseudo second-order kinetics. The removal of Cu(II) ions was higher in the presence of ultrasound than in its absence, but ultrasound reduced the rate constant. The intraparticular diffusion model indicated that adsorption of Cu(II) ions on the granular activated carbon was diffusion controlled as well as that ultrasound promoted intraparticular diffusion.

[Characterization and antimicrobial activity of the bioactive metabolites in streptomycete isolates].

Twenty different streptomycete isolates were obtained from soils of southeast Serbia. Five isolates identified as Streptomyces hygroscopicus (SH100, SH101, SH102, SH103, and SH104) showed strong activity against Botrytis cinerea, a parasite found in domestic vines. These isolates were extensively studied for their in vitro antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeasts and fungi, and also antiviral activity against Herpes simplex. The results indicated that the obtained isolates were highly active against Botrytis cinerea, Candida albicans, and Herpes simplex, with an inhibition zone of approximately 31 mm. The structure of the bioactive components was determined using elemental analysis, as well as UV/VIS, FTIR, and TLC.

Application of the EIIP/ISM bioinformatics concept in development of new drugs.

The development of a new therapeutic drug is a complex, lengthy and expensive process. On average, only one out of 10,000 - 30,000 originally synthesized compounds will clear all the hurdles on the way to becoming a commercially available drug. The process of early and full preclinical discovery and clinical development for a new drug can take twelve to fifteen years to complete, and cost approximately 800 million dollars. The field of bioinformatics has become a major part of the drug discovery pipeline playing a key role in improvement and acceleration of this time and money consuming process. Here we reviewed the application of the EIIP/ISM bioinformatics concept for the development of new drugs. This approach, connecting the electron-ion interaction potential of organic molecules and their biological properties, can significantly reduce development time through (i) identification of promising lead compounds that have some activity against a disease by fast virtual screening of the large molecular libraries, (ii) refinement of selected lead compounds in order to increase their biological activity, and (iii) identification of domains of proteins and nucleotide sequences representing potential targets for therapy. Special attention is paid in this review to the application of the EIIP/ISM bioinformatics platform along with other experimental techniques (screening of a phage displayed peptide libraries, testing selected peptides and small molecules for antiviral activity in vitro) in development of HIV entry inhibitors, representing a new generation of the AIDS drugs.

The effect of agitation intensity on alkali-catalyzed methanolysis of sunflower oil.

The sunflower oil methanolysis was studied in a stirred reactor at different agitation speeds. The measurements of drop size, drop size distribution and the conversion degree demonstrate the effects of the agitation speed in both non-reaction (methanol/sunflower oil) and reaction (methanol/KOH/sunflower oil) systems. Drop size distributions were found to become narrower and shift to smaller sizes with increasing agitation speed as well as with the progress of the methanolysis reaction at a constant agitation speed. During the methanolysis reaction, the Sauter-mean drop diameter stays constant in the initial slow reaction region, rapidly decreases during the fast reaction period and finally reaches the equilibrium level. Due to the fact that the interfacial area increases, one can conclude that the rate of reaction occurring at the interface will also be enhanced progressively. The "autocatalytic" behavior of the methanolysis reaction is explained by this "self-enhancement" of the interfacial area, due to intensive drop breakage process.

Ultrasonic extraction of oil from tobacco (Nicotiana tabacum L.) seeds.

The ultrasonic extraction (UE) of oil from the seeds of a semi-oriental tobacco (Nicotiana tabacum L.) plant strain by using n-hexane and petroleum ether was studied at different temperatures and seeds-to-solvent ratios. The oil yield depended on the seed comminution, the extraction temperature, the seeds-to-solvent ratio and the type of solvent. The oil yield was much higher if the seeds were ground before extraction. The oil yield increased with increasing the extraction temperature and with decreasing the seeds-to-solvent ratio. n-Hexane was somewhat more efficient in the oil extraction than petroleum ether. In recovering the tobacco seed oil (TSO), the UE was less efficient than the Soxhlet extraction. The advantage of the UE was a relatively high oil yield at 25 degrees C in a shorter time. The kinetics of UE of TSO was described using the model of unsteady diffusion through plant material.

Kinetics of ultrasonic extraction of extractive substances from garden (Salvia officinalis L.) and glutinous (Salvia glutinosa L.) sage.

The kinetics of ultrasonic extraction of extractive substances (ES) from dry herbs of garden (Salvia officinalis L.) and glutinous (Salvia glutinosa L.) sage using petroleum ether, 70% ethanol or water at 40 degrees C, as well as the composition of dry extracts, were studied. The mechanism of ultrasonic extraction is confirmed to occur in two steps: first, dissolution of the ES near the particle surface (washing) and, second, diffusion from the solid particles to the bulk of the liquid extract (slow extraction). The process is described mathematically using three concepts of the unsteady diffusion through plant material, the film theory and the empirical equation of Ponomaryov. The yield of ES increases with increasing solvent polarity, and nearly the maximum concentration of ES in liquid extracts is achieved for about 20 min. The composition of extracts depends on both the extraction conditions applied and the plant material.

Theoretical stability assessment of uranyl phosphates and apatites: selection of amendments for in situ remediation of uranium.

Addition of an amendment or reagent to soil/sediment is a technique that can decrease mobility and reduce bioavailability of uranium (U) and other heavy metals in the contaminated site. According to data from literature and results obtained in field studies, the general mineral class of apatites was selected as a most promising amendment for in situ immobilization/remediation of U. In this work we presented theoretical assessment of stability of U(VI) in four apatite systems (hydroxyapatite (HAP), North Carolina Apatite (NCA), Lisina Apatite (LA), and Apatite II) in order to determine an optimal apatite soil amendment which could be used for in situ remediation of uranium. In this analysis we used a theoretical criterion which is based on calculation of the ion-ion interaction potential, representing the main term of the cohesive energy of the matrix/pollutant system. The presented results of this analysis indicate (i) that the mechanism of immobilization of U by natural apatites depends on their chemical composition and (ii) that all analyzed apatites represent, from the point of view of stability, promising materials which could be used in field remediation of U-contaminated sites.

Localization of recognition site between transforming growth factor-beta1 (TGF-beta1) and TGF beta receptor type II: possible implications in breast cancer.

Although overexpression of TGF-beta1 protein has been demonstrated in advanced breast cancer (BC) patients, as well as in other solid tumours, the molecular mechanism of this process remains obscure. This paper proposes that a genetic/epigenetic alteration might occur in the TGF-beta1 gene, within the region coding for the recognition site with TGFbeta receptor type II, leading to a disruption of the ligand-receptor interaction and triggering the TGF-beta1 cascade-related BC progression. To establish the operational framework for this hypothesis, in the present study, this recognition site was identified by the Informational Spectrum Method (ISM) to comprise two TGF-beta1 peptides (positions 47-66 aa and 83-112 aa) and one receptor peptide at positions 112-151 aa of the extracellular domain of the receptor (TbetaRIIM). The TbetaRIIM locus was further evaluated by ISM-derived deletion analysis of the TbetaRII sequences. To provide experimental support for the proposed model, a pilot study of plasma TGF-beta1 analysis was performed in advanced BC patients (n = 8). Two commercial ELISA assays, one with specific alphaTGF-beta1 MAb (MAb) and other with TbetaRIIM as the immobilized phase, revealed pronounced differences in the pattern of plasma TGF-beta1 elevation. In MAb-profile, the TGF-beta1 increase was detected in 7 of 8 patients, whereas analogous TbetaRIIM-profile revealed the elevation in 3 of 8 patients, taking a 50% of maximal elevation as the cut-off value. These findings are consistent with the proposed aberration of TGF-beta1 ligand within the TbetaRII recognition site. Summarizing, this model system is a good starting point for further genetic studies, particularly on genetic/epigenetic alterations of sequences involved in TGF-beta1 and TbetaRIIM interaction, with putative prognostic value for breast cancer.

Design of peptide mimetics of HIV-1 gp120 for prevention and therapy of HIV disease.

It has been reported that the C-terminus of the second conserved region (C2) of the envelope glycoprotein gp120, encompassing peptide RSANFTDNAKTIIVQLNESVEIN (NTM), is important for infectivity and neutralization of the human immunodeficiency virus type 1 (HIV-1). It was also demonstrated that human natural anti-vasoactive intestinal peptide (VIP) antibodies reactive with this gp120 region play an important role in control of HIV disease progression. The bioinformatic analysis based on the time-frequency signal processing revealed non-obvious similarities between NTM and VIP. When tested against a battery of sera from 46 AIDS patients, these peptides, in spite of a significant difference in their primary structures, showed a similar reactivity profiles (r = 0.83). Presented results point out that similarity in the periodical pattern of some physicochemical properties in primary structures of peptides plays a significant role in determination of their immunological crossreactivity. Based on these findings, we propose this bioinformatic criterion be used for design of VIP/NTM peptide mimetics for prevention and treatment of HIV disease.

The role of passive immunization in hiv-positive patients : a case report.

An HIV-positive patient presented with pulmonary tuberculosis as her AIDS-defining diagnosis in 1993 and was effectively treated with 12 months of standard antituberculosis medications (isoniazide, rifampin, and pyrazinamide for 2 months). She received zidovudine for 6 weeks at the time of her diagnosis; however, because of patient preference, she has not received subsequent standard HIV medications (7 years). Her CD4 count at the time of diagnosis (1993) was 297/microL. Monthly passive immunotherapy was administered (fresh frozen plasma from HIV-negative blood donors with a significant titer for the anti-vasoactive intestinal peptide [VIP]/NTM antibody) from December 1993 to June 1994. Her CD4 count increased to > 400/microL during the passive immunotherapy and has remained stable for the past 6 years. The rational for the use of anti-VIP/NTM antibodies preparations in HIV, the possible mode of action of anti-VIP/NTM antibodies, the use of Ig preparations, and the role of exercise as a natural source of anti-VIP/NTM antibodies are discussed. This case report supports the potential therapeutic use of anti-VIP antibodies for treatment of HIV disease.

AIDS epidemic at the beginning of the third millennium: time for a new AIDS vaccine strategy.

Current expansion of AIDS pandemic significantly accelerates AIDS vaccine research resulting in development and clinical testing of several AIDS vaccine candidates. At the same time, available experimental and clinical data demonstrate that current AIDS vaccine strategy is unsuccessful resulting in development of inefficient and harmful vaccines. This overview briefly summarizes reported results which point out the requirement for moratorium on the current clinical trials of HIV-1 gp120/160 vaccines and urgent need for development of a new, efficient and safe AIDS vaccine strategy.

Anti-V3 and anti-IgG antibodies of healthy individuals share complementarity structures.

It was recently shown that antibodies reactive with a peptide from the tip of the HIV-1NY5 gp120 V3 loop (V3 peptide) are present not only in sera of HIV-positive patients but also in sera of healthy HIV-negative individuals. In the present study, we show that V3 peptide reactive antibodies are predominantly IgM in sera of HIV negative individuals and that a fraction of the IgG anti-V3 antibodies exhibit features of autoantibodies. These antibodies were purified by chromatography on IgG-sepharose columns from sera as well as from purified IgG anti-V3 antibodies. A higher IgG anti-V3 reactivity was detected in autoantibody preparations from HIV-positive sera as compared with the reactivity of sera and purified antibodies from HIV-negative individuals. This was confirmed by solid phase binding of IgG anti-V3 antibodies both to V3 and to human IgG F(ab')2 antigens. The autoantibodies did not bind to peptides that share sequence similarity with V3 peptide indicating a high epitope specificity. The detection of antibodies against HIV epitopes in HIV-negative individuals may suggest that anti-V3 antibodies after HIV infection represent at least in part a secondary immune response.

Human immunodeficiency virus V3 peptide-reactive antibodies are present in normal HIV-negative sera.

A structural relation between consensus sequences of the portion of HIV-1 gp120 involving the V3 loop (V3 peptide) and the variable domains of human immunoglobulin members of the VH-III gene family was proposed to trigger an imbalance of the idiotypic network during the course of HIV infection. Thus, the repertoires of immunoglobulins in healthy individuals should contain antigenic determinant(s) complementary to particular V3 loop epitope(s). In this study we investigated the specific binding to the V3 peptide of antibodies present in sera of HIV-positive and of clinically normal HIV-negative subjects. Two groups of HIV-positive sera differing in antibody titers to V3 peptide, arbitrarily referred here as high- and low-reactive HIV-positive sera, were distinguished on the basis of an ELISA. Antibodies were affinity purified on V3 peptide and their titers in both HIV-negative and low-reactive HIV-positive sera were nearly superimposable and much lower than the titers of those from high-reactive HIV-positive sera. Also, the quality of the two groups of antibodies differed: much higher amounts of soluble V3 peptide were needed to partly compete the binding of antibodies from HIV-negative sera to insoluble V3 peptide as compared with those from HIV-positive sera, suggesting that the latter had higher affinity for V3 peptide. All of the affinity-purified antibodies bound poorly to unrelated peptides, even to those sharing sequence similarity with the V3 peptide. The present observations suggest that in HIV infection antigen-driven affinity maturation of preimmune immunoglobulins with idiotypes complementary to V3 epitope(s) participating in physiological autoreactivity might be at work.

Identification of an active Chi recombinational hot spot within the HIV-1 envelope gene: consequences for development of AIDS vaccines.

Because of a sequence similarity between the HIV-1 envelope glycoprotein gp120 and the variable region of human immunoglobulins, we have suggested that the use of this protein as a vaccine component could strongly influence the host immune system, making it more vulnerable to HIV, and in the long term, accelerate disease progression in asymptomatic HIV patients. Using a chimeric primer consisting of the nucleotide sequence derived from the HIV-1 env gene coding for the second conserved region of gp120, and the highly conserved sequence derived from the human immunoglobulin gene coding for the V(H)III domain, we have identified in sera of AIDS patients HIV-1 field isolates carrying the complete and active Chi recombinational hot spot (GCTGGTGG). We have also demonstrated in vivo recombination between the HIV-1 gene coding for the central portion of the gp120 involving the V3 loop and the bacterial gene coding for the clp protease. These results strongly support and reinforce the previous contention and the serious concern that AIDS vaccine candidates carrying the HIV-1 env gene on viral and bacterial vectors, could result in the generation of new pathogens with unpredictable effects on the immune system.

Factors affecting the ability of the renal medulla to exert an antihypertensive function.

To examine whether changes in renomedullary osmolality and the activity of the renin-angiotensin system may influence the ability of the renal medulla to exert an antihypertensive function, rats were exposed to several manoeuvers. These affected either the medullary osmolality or the renin-angiotensin system (salt or saccharose load, salt depletion, treatment with captopril alone or in combination with salt depletion). A comparison of the antihypertensive capacity of the renal medulla was studied by transplanting renal medullae from the various groups into one-kidney one-clip hypertensive rats. A significant and quantitatively similar reduction in blood pressure was observed in hypertensive rats that received transplants of the medullae from control, salt or saccharose loaded rats and captopril treated rats. In contrast, medullae from salt depleted rats did not affect blood pressure when transplanted into hypertensive animals. The addition of captopril restored the antihypertensive function of renal medulla in salt depleted rats. The results do not support the view that osmolality of the renal medulla regulates its antihypertensive capacity, and suggest that angiotensin II may restrain renomedullary antihypertensive function.

Further evidence for the relationship of HIV-1 gp120 V3 loops with Ig superfamily members: similarity with the putative CDR3 region of T-cell receptor delta-chains.

Twenty-five V3 loops of envelope gp 120 extracted from 30 HIV-1 isolates were compared with T-cell receptor (TCR) subunits variable (V) portions using pairwise alignments of 11-residue peptides. The results indicate that, in comparison with random sequences, the analyzed V3 loops, unlike control (unrelated) sequences, display highly significant local similarity with TCR V delta (p approximately 10(-20)). However, pattern-matching searches were performed on a much larger number of V3 loops (484). In particular, selective pattern TR * * * NT * K * I is shared by V delta from human T-cell line KT19E and 230 HIV-1 V3 loops (N-terminal portion). Pattern RA * YT * * * I * G is common for V delta chain isolated from T-cell line DS6 of an immunodeficient patient and 69 V3 loops (C-terminal portion). The presented delta-chain portions of sequence similarity with the V3 loops overlap the putative complementarity-determining region (CDR3), thus possibly indicating functional similarity too.