Optimization of nickel and cobalt biosorption by native Serratia marcescens strains isolated from serpentine deposits using response surface methodology

The treatment of metal-polluted wastes is a challenging issue of environmental concern. Metals can be removed using microbial biomass, and this is an interesting approach towards the design of eco-friendly technologies for liquid waste treatment. The study reported here aimed to optimize nickel and cobalt biosorption from aqueous solutions using three native metal-resistant Serratia marcescens strains. Ni(II) and Co(II) biosorption by S. marcescens strains was found to fit better to Langmuir's model, with maximum uptake capacities of 13.5 mg g^-1 for Ni(II) ions and 19.9 mg g^-1 for Co(II) ions. Different experimental conditions of initial metal concentration, pH, initial biomass, and temperature were optimized using the Plackett-Burman method, and, finally, biomass and metal concentration were studied using the response surface methodology (RSM) to improve biosorption. The optimum uptake capacities for Co(II) ions by the three biosorbents used were obtained for initial metal concentrations of 35-40 mg L^-1 and an initial biomass of 6 mg. For Ni(II) ions, the optimum uptake capacity was achieved with 1 mg of initial biomass for S. marcescens C-1 and C-19, and with 7 mg for S. marcescens C-16, with initial concentrations of 20-50 mg L^-1. The results obtained demonstrate the viability of native S. marcescens strains as biosorbents for Ni(II) and Co(II) removal. This study also contributes to our understanding of the potential uses of serpentine microbial populations for the design of environmental cleanup technologies.

Biosorption of nickel, cobalt, zinc and copper ions by Serratia marcescens strain 16 in mono and multimetallic systems

The metallurgical industry is one of the main sources of heavy metal pollution, which represents a severe threat to life. Metals can be removed from aqueous solutions by using microbial biomasses. This paper analyses the heavy metal biosorption capacity of Serratia marcescens strain 16 in single and multimetallic systems. The results obtained show that Co(II), Ni(II) and Zn(II) biosorption in monometallic systems is two to three times higher than in the presence of bi-metallic and multimetallic solutions. Fourier transform infrared spectroscopy confirmed that carbonyl, carboxyl and hydroxyl were the main functional groups, as well as the amide bands I and II involved in metal uptake, which are present in external structures of the bacterial cell. The results obtained demonstrated the viability of S. marcescens strain 16 as a biosorbent for the design of eco-friendly technologies for the treatment of waste liquor.

In-solution buffer-free digestion allows full-sequence coverage and complete characterization of post-translational modifications of the receptor-binding domain of SARS-CoV-2 in a single ESI-MS spectrum

Subunit vaccines based on the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 provide one of the most promising strategies to fight the COVID-19 pandemic. The detailed characterization of the protein primary structure by mass spectrometry (MS) is mandatory, as described in ICHQ6B guidelines. In this work, several recombinant RBD proteins produced in five expression systems were characterized using a non-conventional protocol known as in-solution buffer-free digestion (BFD). In a single ESI-MS spectrum, BFD allowed very high sequence coverage (≥ 99%) and the detection of highly hydrophilic regions, including very short and hydrophilic peptides (2-8 amino acids), and the His6-tagged C-terminal peptide carrying several post-translational modifications at Cys538 such as cysteinylation, homocysteinylation, glutathionylation, truncated glutathionylation, and cyanylation, among others. The analysis using the conventional digestion protocol allowed lower sequence coverage (80-90%) and did not detect peptides carrying most of the above-mentioned PTMs. The two C-terminal peptides of a dimer [RBD(319-541)-(His)6]2 linked by an intermolecular disulfide bond (Cys538-Cys538) with twelve histidine residues were only detected by BFD. This protocol allows the detection of the four disulfide bonds present in the native RBD, low-abundance scrambling variants, free cysteine residues, O-glycoforms, and incomplete processing of the N-terminal end, if present. Artifacts generated by the in-solution BFD protocol were also characterized. BFD can be easily implemented; it has been applied to the characterization of the active pharmaceutical ingredient of two RBD-based vaccines, and we foresee that it can be also helpful to the characterization of mutated RBDs.

Recombinant Mycobacterium bovis BCG is a promising platform to develop vaccines against Trypansoma cruzi infection

Chagas disease, caused by the hemoflagelate parasite Trypanosoma cruzi, is one of the most prevalent endemic parasitoses, affecting 7-8 million people. Due to the complexity of the infection, no vaccines are available at present. The extraordinary adjuvant capacity of bacille Calmette-Guérin (BCG) was explored in this work to develop a vaccine candidate to protect against T. cruzi infection using the recombinant BCG (rBCG) vaccine platform. Three antigens of the parasite corresponding to the N and C terminal fragments of the enzyme trans-sialidase (NT-TS and CT-TS, respectively) and a fragment of the cruzipain enzyme (CZf) were cloned into the vectors pUS997 and pUS2000 and transformed into the BCG Pasteur strain. In vaccinated mice, rBCG expressing NT-TS in pUS2000 plasmid provided the highest protection and the lowest parasitemia after challenging BALB/c mice with a 50% lethal dose of parasites. When mice vaccinated with pUS2000-NT-TS were challenged with a 100% lethal dose of parasite, high levels of protection were also obtained, together with a low degree of cardiac lesions 120 days after infection. In immunized mice with pUS2000-NT-TS/rBCG clone, the proliferation of CD4⁺ cells from splenocytes stimulated with the TS antigen was significant; this stimulation increased interferon (IFN)-γ and interleukin (IL)-17 within CD4⁺ T lymphocytes (LTCD4⁺ ) cells and IFN-γ and CD107 expression within LTCD8⁺ cells. Therefore, pUS2000-NT-TS/rBCG conferred high levels of protection, which correlated with an immune response orientated towards a T helper type 1 (Th1)/Th17 profile, together with an LTC-specific response, indicating that rBCG is a promising platform to develop vaccines against T. cruzi.

Functional and Mass Spectrometric Evaluation of an Anti-Tick Antigen Based on the P0 Peptide Conjugated to Bm86 Protein

A synthetic 20 amino acid peptide of the ribosomal protein P0 from ticks, when conjugated to keyhole limpet hemocyanin from Megathura crenulata and used as an immunogen against Rhipicephalus microplus and Rhipicephalus sanguineus s.l. species, has shown efficacies of around 90%. There is also experimental evidence of a high efficacy of this conjugate against Amblyomma mixtum and Ixodes ricinus species, which suggest that this antigen could be a good broad-spectrum anti-tick vaccine candidate. In this study, the P0 peptide (pP0) was chemically conjugated to Bm86 as a carrier protein. SDS-PAGE analysis of this conjugate demonstrated that it is highly heterogeneous in size, carrying from 1 to 18 molecules of pP0 per molecule of Bm86. Forty-nine out of the 54 lysine residues and the N-terminal end of Bm86 were found partially linked to pP0 by using LC-MS/MS analysis and the combination of four different softwares. Several post-translational modifications of Bm86 protein were also identified by mass spectrometry. High immunogenicity and efficacy were achieved when dogs and cattle were vaccinated with the pP0-Bm86 conjugate and challenged with R. sanguineus s.l. and R. microplus, respectively. These results encourage the development of this antigen with promising possibilities as an anti-tick vaccine.

Plasticity of the HEK-293 cells, related to the culture media, as platform to produce a subunit vaccine against classical swine fever virus

Classical swine fever (CSF) is a contagious disease that causes a high mortality to domestic and wild pigs. Its causative agent is an enveloped Pestivirus named Classical Swine Fever Virus (CSFV). Due to the huge economic affectations produced by this disease to porcine industry, several vaccines have been developed using principally the CSFV E2 glycoprotein. Recently, a subunit vaccine based on this structural protein of the CSFV fused to the porcine CD154 molecule as immunomodulator named E2-CD154 was assayed by us. This chimeric protein was produced in the Human Embryonic Kidney (HEK-293) cell line. In this work, the growth and the expression profiles of HEK-293 E2-CD154 cells in four commercially available culture media were studied. The oligosaccharide structures in the N-glycosylation patterns of the E2-CD154 protein produced by this cell line in 10 L fermenters with two different culture media were also analyzed. In addition, the neutralizing antibody response generated in mice vaccinated with these antigens was assayed. Our results suggest that the culture media CDM4HEK293 and SFM4HEK293 which are recommended for HEK-293 growth are the best choice to growth the cell clone expressing the E2-CD154 protein. The glycosylation pattern and the neutralizing antibody response generated by the E2-CD154 protein were independent of the culture medium used which demonstrates the high reproducibility and consistency among protein batches produced by HEK-293 cells even in different culture conditions.

Interfacial Tension Properties in Biopolymer Blends: From Deformed Drop Retraction Method (DDRM) to Shear and Elongation Rheology-Application to Blown Film Extrusion

Shear and elongation rheology have been used in order to quantify the interfacial tension properties of PLA_PBAT blends. A multi-functional epoxide (Joncryl) has been chosen as a compatibilizer. From small amplitude oscillatory shear (SAOS), the results show that the addition of the Joncryl into the blends increased largely the shear rheological properties (elasticity, shear-thinning behavior) and contributed to very long relaxation process. This relaxation process is characterized by the presence of a G′ shoulder at lower angular frequencies. Scanning and transmission electron microscopy (SEM and TEM) observations show a finer morphology thus confirming the improvement of interfacial properties of the compatibilized blends. The interfacial tension has been firstly quantified using the deformed drop retraction method (DDRM). These experiments elucidated some of the effects of phase elasticity on both deformation mechanism and break-up conditions. A decrease of the interfacial tension has been demonstrated for the compatibilized blends. Secondly, the same trend was also highlighted using the emulsion Palierne model (simplified and generalized versions). Finally, the interfacial tension value was extracted from the measurements of extensional properties. A good accuracy with the two latter methods was obtained. This decrease of the interfacial tension nicely demonstrated the role of Joncryl as an efficient compatibilizer for a better handling of blow PLA-PBAT film extrusion process.

High accumulation in tobacco seeds of hemagglutinin antigen from avian (H5N1) influenza

Tobacco seeds can be used as a cost effective system for production of recombinant vaccines. Avian influenza is an important respiratory pathogen that causes a high degree of mortality and becomes a serious threat for the poultry industry. A safe vaccine against avian flu produced at low cost could help to prevent future outbreaks. We have genetically engineered tobacco plants to express extracellular domain of hemagglutinin protein from H5N1 avian influenza virus as an inexpensive alternative for production purposes. Two regulatory sequences of seed storage protein genes from Phaseolus vulgaris L. were used to direct the expression, yielding 3.0 mg of the viral antigen per g of seeds. The production and stability of seed-produced recombinant HA protein was characterized by different molecular techniques. The aqueous extract of tobacco seed proteins was used for subcutaneous immunization of chickens, which developed antibodies that inhibited the agglutination of erythrocytes after the second application of the antigen. The feasibility of using tobacco seeds as a vaccine carrier is discussed.

Comparison of Kaposi Sarcoma Risk in Human Immunodeficiency Virus-Positive Adults Across 5 Continents: A Multiregional Multicohort Study

BACKGROUND

We compared Kaposi sarcoma (KS) risk in adults who started antiretroviral therapy (ART) across the Asia-Pacific, South Africa, Europe, Latin, and North America.

METHODS

We included cohort data of human immunodeficiency virus (HIV)-positive adults who started ART after 1995 within the framework of 2 large collaborations of observational HIV cohorts. We present incidence rates and adjusted hazard ratios (aHRs).

RESULTS

We included 208140 patients from 57 countries. Over a period of 1066572 person-years, 2046 KS cases were diagnosed. KS incidence rates per 100000 person-years were 52 in the Asia-Pacific and ranged between 180 and 280 in the other regions. KS risk was 5 times higher in South African women (aHR, 4.56; 95% confidence intervals [CI], 2.73-7.62) than in their European counterparts, and 2 times higher in South African men (2.21; 1.34-3.63). In Europe, Latin, and North America KS risk was 6 times higher in men who have sex with men (aHR, 5.95; 95% CI, 5.09-6.96) than in women. Comparing patients with current CD4 cell counts ≥700 cells/µL with those whose counts were <50 cells/µL, the KS risk was halved in South Africa (aHR, 0.53; 95% CI, .17-1.63) but reduced by ≥95% in other regions.

CONCLUSIONS

Despite important ART-related declines in KS incidence, men and women in South Africa and men who have sex with men remain at increased KS risk, likely due to high human herpesvirus 8 coinfection rates. Early ART initiation and maintenance of high CD4 cell counts are essential to further reducing KS incidence worldwide, but additional measures might be needed, especially in Southern Africa.

Protein content of the Hylesia metabus egg nest setae (Cramer [1775]) (Lepidoptera: Saturniidae) and its association with the parental investment for the reproductive success and lepidopterism

Hylesia metabus is a neotropical moth possessing toxic setae, which once in contact with the skin cause a severe dermatitis to humans known as lepidopterism. The only known function of the setae in the life cycle is to provide protection during the mating and egg-hatching stages. Approximately 65% of the protein content of the setae is a cluster of five proteases (28-45kDa) showing sequence homology to other S1A serine proteases. The N-glycans of a 40kDa protease are a mixture of neutral and sulfated G0F structures. The sulfated N-glycans have an important role in triggering the inflammatory response typical of lepidopterism while the proteolytic activity may promote the erosion of blood vessels and tissues causing focal hemorrhages. The presence of Chitinase and a 30kDa lipoprotein is probably related to the antifungal defense. In addition, chitin digestion of the setae may potentiate the inflammatory reaction caused by the toxins due to the formation of chitin adjuvants fragments. The combined effect of proteases and a chitinase may dissuade predating arthropods, by damaging their exoskeletons. Vitellogenin, a bacteriostatic protein, is able to recognize pathogen-associated patterns, which suggests its possible role in protecting the embryonated eggs from pathogenic microorganisms.

SIGNIFICANCE

The present study is the first report describing the different protein species present in the urticating egg nest setae of the neotropical moth Hylesia metabus - the most harmful of the Hylesia moths - causing a severe urticating dermatitis in humans known as lepidopterism. A distinctive feature of the venom is the presence of five different S1A serine proteases probably used to guarantee a more efficient degradation of a wider number of protein substrates. This work confirms that the presence of sulfated N-glycans is not an isolated finding since its presence has been demonstrated in two different proteases affirming that this PTM is of importance for the activation of the inflammatory response typical of lepidopterism. Additionally, this study gives useful information on the defense mechanisms used for protection of its progeny vs. vertebrate predators, fungus, bacteria or other arthropods such as ants. The proteins detected in the egg nest should be seen as an extended parental effort made by the females in order to achieve an optimal reproductive success, thus compensating for the considerable loss of progeny during the larval stages that seriously limits the number of sexually mature adults reaching the reproductive phase.

Structural characterization and biological implications of sulfated N-glycans in a serine protease from the neotropical moth Hylesia metabus (Cramer [1775]) (Lepidoptera: Saturniidae)

Contact with the urticating setae from the abdomen of adult females of the neo-tropical moth Hylesia metabus gives rise to an urticating dermatitis, characterized by intense pruritus, generalized malaise and occasionally ocular lesions (lepidopterism). The setae contain a pro-inflammatory glycosylated protease homologous to other S1A serine proteases of insects. Deglycosylation with PNGase F in the presence of a buffer prepared with 40% H2 (18)O allowed the assignment of an N-glycosylation site. Five main paucimannosidic N-glycans were identified, three of which were exclusively α(1-6)-fucosylated at the proximal GlcNAc. A considerable portion of these N-glycans are anionic species sulfated on either the 4- or the 6-position of the α(1-6)-mannose residue of the core. The application of chemically and enzymatically modified variants of the toxin in an animal model in guinea pigs showed that the pro-inflammatory and immunological reactions, e.g. disseminated fibrin deposition and activation of neutrophils, are due to the presence of sulfate-linked groups and not on disulfide bonds, as demonstrated by the reduction and S-alkylation of the toxin. On the other hand, the hemorrhagic vascular lesions observed are attributed to the proteolytic activity of the toxin. Thus, N-glycan sulfation may constitute a defense mechanism against predators.

Fabry disease and enzyme replacement therapy in classic patients with same mutation: different formulations--different outcome?

We describe the results of the multidisciplinary evaluation in patients with Fabry disease and the same genetic mutation and their outcomes using different approved enzyme replacement therapy (ERT). We measured baseline data and serial results of neuropathic pain assessment and renal, cardiac and cerebrovascular functioning. Pain scale showed improvement in all male cases treated with agalsidasa beta. A mild improvement was detected in agalsidasa alfa-treated patients after 1 year with posterior increase. During the agalsidase beta shortage, two male patients were switched to agalsidasa alfa, after 1 year both cases presented an increase in scale values. Renal evolution showed a tendency toward a decrease in proteinuria in patients using agalsidase beta and worsening with agalsidase alfa. We found improvement in two females using agalsidase beta and no changes in the other cases regarding cardiac functioning. Brain magnetic resonance imaging (MRI) showed increase of white matter lesions in four patients. Improvement and stabilization in neuropathic pain, renal and cardiac functioning and brain MRI were found mainly in patients treated with agalsidase beta. Following the reported recommendations on reintroduction of agalsidase beta after the enzyme shortage, we decided to switch all patients to agalsidase beta.

Computational proteomics pitfalls and challenges: HavanaBioinfo 2012 workshop report

The workshop "Bioinformatics for Biotechnology Applications (HavanaBioinfo 2012)", held December 8-11, 2012 in Havana, aimed at exploring new bioinformatics tools and approaches for large-scale proteomics, genomics and chemoinformatics. Major conclusions of the workshop include the following: (i) development of new applications and bioinformatics tools for proteomic repository analysis is crucial; current proteomic repositories contain enough data (spectra/identifications) that can be used to increase the annotations in protein databases and to generate new tools for protein identification; (ii) spectral libraries, de novo sequencing and database search tools should be combined to increase the number of protein identifications; (iii) protein probabilities and FDR are not yet sufficiently mature; (iv) computational proteomics software needs to become more intuitive; and at the same time appropriate education and training should be provided to help in the efficient exchange of knowledge between mass spectrometrists and experimental biologists and bioinformaticians in order to increase their bioinformatics background, especially statistics knowledge.

Fabry disease in Argentina: an evaluation of patients enrolled in the Fabry Registry

AIMS

Fabry disease (FD) is an X-linked inborn error of metabolism caused by alpha-galactosidase A deficiency. The Fabry Registry is an ongoing, global observational database that compiles clinical data from patients with FD.

METHODS

Demographic and baseline clinical characteristics of Fabry Registry patients enrolled in Argentina were analysed and compared with patients enrolled in the rest of the world (ROW). Baseline clinical parameters included chronic kidney disease (CKD) stage, urine protein-to-creatinine ratio and left ventricular posterior wall thickness. Only data from untreated patients were included.

RESULTS

As of 1 October 2010, 3752 patients were enrolled in the Registry, 70 patients from Argentina and 3682 from the ROW. Argentinean male subjects were younger than Fabry Registry male subjects enrolled in ROW: mean current age 32.5 years vs. 39.0 years for men (p = 0.0257 by t-test). The current age (mean ± standard deviation) of female subjects enrolled in Argentina was not significantly different from that of female subjects enrolled in the ROW: 40.1 ± 17.28 vs. 43.2 ±17.95 years respectively (p = 0.2967). Overall, a smaller percentage of patients from Argentina received ERT compared with patients in the ROW (54% vs. 58% respectively). When evaluated by gender, more men and fewer women in Argentina received ERT compared with ROW (85% vs. 79% for men and 27% vs. 38% for women). A larger proportion of patients in ROW had severe CKD (stage 4 or 5) compared with Argentina (9.8% vs. 0%), most likely because of the older age of the ROW population.

CONCLUSIONS

The enrolment of Argentinean patients into the Fabry Registry has steadily increased, as has the inclusion of female and paediatric patients with FD. The medical community in Argentina should be aware of FD in these populations, as awareness will facilitate prompt diagnosis and initiation of treatment, thus leading to improved outcomes.

Comparative in vitro and experimental in vivo studies of the anti-epidermal growth factor receptor antibody nimotuzumab and its aglycosylated form produced in transgenic tobacco plants

A broad variety of foreign genes can be expressed in transgenic plants, which offer the opportunity for large-scale production of pharmaceutical proteins, such as therapeutic antibodies. Nimotuzumab is a humanized anti-epidermal growth factor receptor (EGFR) recombinant IgG1 antibody approved in different countries for the treatment of head and neck squamous cell carcinoma, paediatric and adult glioma, and nasopharyngeal and oesophageal cancers. Because the antitumour mechanism of nimotuzumab is mainly attributed to its ability to interrupt the signal transduction cascade triggered by EGF/EGFR interaction, we have hypothesized that an aglycosylated form of this antibody, produced by mutating the N(297) position in the IgG(1) Fc region gene, would have similar biochemical and biological properties as the mammalian-cell-produced glycosylated counterpart. In this paper, we report the production and characterization of an aglycosylated form of nimotuzumab in transgenic tobacco plants. The comparison of the plantibody and nimotuzumab in terms of recognition of human EGFR, effect on tyrosine phosphorylation and proliferation in cells in response to EGF, competition with radiolabelled EGF for EGFR, affinity measurements of Fab fragments, pharmacokinetic and biodistribution behaviours in rats and antitumour effects in nude mice bearing human A431 tumours showed that both antibody forms have very similar in vitro and in vivo properties. Our results support the idea that the production of aglycosylated forms of some therapeutic antibodies in transgenic plants is a feasible approach when facing scaling strategies for anticancer immunoglobulins.

Role of matrix metalloproteinases 2 and 9 in ex vivo Trypanosoma cruzi infection of human placental chorionic villi

BACKGROUND

Chagas' disease is caused by the haemophlagelated protozoan Trypanosoma cruzi (T. cruzi). During congenital transmission the parasite breaks down the placental barrier. In the present study we analyzed the participation of matrix metalloproteases (MMPs) in the extracellular matrix (ECM) remodeling during T. cruzi ex vivo infection of human placental chorionic villi explants.

METHODS

Chorionic villi from healthy woman placentas were incubated in the presence or absence of 10⁵ or 10⁶ T. cruzi trypomastigotes (Y strain) with or without the MMPs inhibitor doxycycline. Effective infection was tested measuring parasite DNA by real time PCR (qPCR). MMP-2 and MMP-9 expression were determined by western blotting and immunohistochemistry and their activities were measured by zymography. The effect of MMPs on ECM structure was analyzed histochemically.

RESULTS

T. cruzi induces the expression and activity of MMP-2 and MMP-9 in chorionic villi. Inhibition of the MMPs prevents the tissue damage induced by T. cruzi and partially decreases the ex vivo infection of the chorionic villi.

CONCLUSION

MMPs are partially responsible for the ECM changes observed in human chorionic villi during T. cruzi infection and participate in tissue invasion. On the other hand, MMPs may be part of a local placental antiparasitic mechanism.

Differential N-glycosylation of a monoclonal antibody expressed in tobacco leaves with and without endoplasmic reticulum retention signal apparently induces similar in vivo stability in mice

Plant cells are able to perform most of the post-translational modifications that are required by recombinant proteins to achieve adequate bioactivity and pharmacokinetics. However, regarding N-glycosylation the processing of plant N-glycans in the Golgi apparatus displays major differences when compared with that of mammalian cells. These differences in N-glycosylation are expected to influence serum clearance rate of plant-derived monoclonal antibodies. The monoclonal antibody against the hepatitis B virus surface antigen expressed in Nicotiana tabacum leaves without KDEL endoplasmic reticulum (ER) retention signal (CB.Hep1(-)KDEL) and with a KDEL (Lys-Asp-Glu-Leu) fused to both IgG light and heavy chains (CB.Hep1(+)KDEL) were tested for in vivo stability in mice. Full characterization of N-glycosylation and aggregate formation in each monoclonal antibody batch was determined. The mouse counterpart (CB.Hep1) was used as control. Both (CB.Hep1(-)KDEL) and (CB.Hep1(+)KDEL) showed a faster initial clearance rate (first 24 h) compared with the analogous murine antibody while the terminal phase was similar in the three antibodies. Despite the differences between CB.Hep1(+)KDEL and CB.Hep1(-)KDEL N-glycans, the in vivo elimination in mice was indistinguishable from each other and higher than the murine monoclonal antibody. Molecular modelling confirmed that N-glycans linked to plantibodies were oriented away from the interdomain region, increasing the accessibility of the potential glycan epitopes by glycoprotein receptors that might be responsible for the difference in stability of these molecules.

DNA repair BER pathway inhibition increases cell death caused by oxidative DNA damage in Trypanosoma cruzi

Trypanosoma cruzi, a parasitic protozoan, is the etiological agent of Chagas disease, an endemic and neglected pathology in Latin America. It presents a life cycle that involves a hematophagous insect and man as well as domestic and wild mammals. The parasitic infection is not eliminated by the immune system of mammals; thus, the vertebrate host serves as a parasite reservoir. Additionally, chronic processes leading to dysfunction of the cardiac and digestive systems are observed. To establish a chronic infection some parasites should resist the oxidative damage to its DNA exerted by oxygen and nitrogen free radicals (ROS/RNS) generated in host cells. Till date there are no reports directly showing oxidative DNA damage and repair in T. cruzi. We establish that ROS/RNS generate nuclear and kinetoplastid DNA damage in T. cruzi that may be partially repaired by the parasite. Furthermore, we determined that both oxidative agents diminish T. cruzi cell viability. This effect is significantly augmented in parasites subsequently incubated with methoxyamine, a DNA base excision repair (BER) pathway inhibitor, strongly suggesting that the maintenance of T. cruzi viability is a consequence of DNA repair mechanisms.

Different strategies for recovering metals from CARON process residue

The capacity of Acidithiobacillus thiooxidans DMS 11478 to recover the heavy metals contained in the residue obtained from the CARON process has been evaluated. Different bioreactor configurations were studied: a two-stage batch system and two semi-continuous systems (stirred-tank reactor leaching and column leaching). In the two-stage system, 46.8% Co, 36.0% Mg, 26.3% Mn and 22.3% Ni were solubilised after 6h of contact between the residue and the bacteria-free bioacid. The results obtained with the stirred-tank reactor and the column were similar: 50% of the Mg and Co and 40% of the Mn and Ni were solubilised after thirty one days. The operation in the column reactor allowed the solid-liquid ratio to be increased and the pH to be kept at low values (<1.0). Recirculation of the leachate in the column had a positive effect on metal removal; at sixty five days (optimum time) the solubilisation levels were as follows: 86% Co, 83% Mg, 72% Mn and Ni, 62% Fe and 23% Cr. The results corroborate the feasibility of the systems studied for the leaching of metals from CARON process residue and these methodologies can be considered viable for the recovery of valuable metals.

Clonostachys rosea BAFC3874 as a Sclerotinia sclerotiorum antagonist: mechanisms involved and potential as a biocontrol agent

AIMS

To establish the modes of action of the antagonistic fungal strain Clonostachys rosea BAFC3874 isolated from suppressive soils against Sclerotinia sclerotiorum and to determine its potential as a biocontrol agent.

METHODS AND RESULTS

The antagonistic activity of C. rosea BAFC3874 was determined in vitro by dual cultures. The strain effectively antagonized S. sclerotiorum in pot-grown lettuce and soybean plants. Antifungal activity assays of C. rosea BAFC3874 grown in culture established that the strain produced antifungal compounds against S. sclerotiorum associated with secondary metabolism. High mycelial growth inhibition coincided with sclerotia production inhibition. The C. rosea strain produced a microheterogeneous mixture of peptides belonging to the peptaibiotic family. Moreover, mycoparasitism activity was observed in the dual culture.

CONCLUSIONS

Clonostachys rosea strain BAFC3874 was proved to be an effective antagonist against the aggressive soil-borne pathogen S. sclerotiorum in greenhouse experiments. The main mechanisms involve peptaibiotic metabolite production and mycoparasitism activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

Clonostachys rosea BAFC3874 may be a good fungal biological control agent against S. sclerotiorum. In addition, we were also able to isolate and identify peptaibols, an unusual family of compounds in this genus of fungi.

Combined strategy for the precipitation of heavy metals and biodegradation of petroleum in industrial wastewaters

The precipitation of chromium(III), copper(II), manganese(II) and zinc(II) by biogenic hydrogen sulfide generated by sulfate-reducing bacteria, Desulfovibrio sp., and the degradation of total petroleum hydrocarbons (TPH) in the presence of heavy metal by Pseudomonas aeruginosa AT18 have been carried out. An anaerobic stirred tank reactor was used to generate hydrogen sulfide with Desulfovibrio sp. culture and the precipitation of more than 95% of each metal was achieved in 24 h (metal solutions contained: 60, 49, 50 and 80 mg L(-1) of chromium, copper, manganese and zinc sulfates). A stirred tank reactor with P. aeruginosa AT18, in the presence of the heavy metal solution and 2% (v/v) of petroleum, led to the degradation of 60% of the total petroleum hydrocarbons and the removal of Cr(III) 99%, Cu(II) 93%, Zn(II) 46% and Mn(II) 88% in the medium through biosorption phenomena. These results enabled the development of an integrated system in which the two processes were combined. The overall aim of the study was achieved, with 84% of TPH degraded and all of the metals completely removed. Work is currently underway aimed at improving this system (decrease in operation time, culture of P. aeruginosa in anaerobic conditions) in an effort to apply this process in the bioremediation of natural media contaminated with heavy metals and petroleum.

Chemical and enzymatic N-glycan release comparison for N-glycan profiling of monoclonal antibodies expressed in plants

Plants synthesize N-glycans containing the antigenic sugars alpha(1,3)-fucose and beta(1,2)-xylose. Therefore it is important to monitor these N-glycans in monoclonal antibodies produced in plants (plantibodies). We evaluated several techniques to characterize the N-glycosylation of a plantibody produced in tobacco plants with and without the KDEL tetrapeptide endoplasmic reticulum retention signal which should inhibit or drastically reduce the addition of alpha(1,3)-fucose and beta(1,2)-xylose. Ammonium hydroxide/carbonate-based chemical deglycosylation and PNGase A enzymatic release were investigated giving similar 2-aminobenzamide-labeled N-glycan HPLC profiles. The chemical release does not generate peptides which is convenient for MS analysis of unlabeled pool but its main drawback is that it induces degradation of alpha1,3-fucosylated N-glycan reducing terminal sugar. Three analytical methods for N-glycan characterization were evaluated: (i) MALDI-MS of glycopeptides from tryptic digestion; (ii) negative-ion ESI-MS/MS of released N-glycans; (iii) normal-phase HPLC of fluorescently labeled glycans in combination with exoglycosidase sequencing. The MS methods identified the major glycans, but the HPLC method was best for identification and relative quantitation of N-glycans. Negative-mode ESI-MS/MS permitted also the correct identification of the linkage position of the fucose residue linked to the inner core N-acteylglucosamine (GlcNAc) in complex N-glycans.

N-glycosylation of plant recombinant pharmaceuticals

N-glycosylation is a maturation event necessary for the correct function, efficiency, and stability of a high number of biopharmaceuticals. This chapter presented here proposes various methods to determine whether, how, and where a plant pharmaceutical is N-glycosylated. These methods rely on blot detection with glycan-specific probes, specific deglycosylation of glycoproteins followed by mass spectrometry, N-glycan profile analysis, and glycopeptide identification by LC-MS.

Plant N-glycan profiling of minute amounts of material

Development of convenient strategies for identification of plant N-glycan profiles has been driven by the emergence of plants as an expression system for therapeutic proteins. In this article, we reinvestigated qualitative and quantitative aspects of plant N-glycan profiling. The extraction of plant proteins through a phenol/ammonium acetate procedure followed by deglycosylation with peptide N-glycosidase A (PNGase A) and coupling to 2-aminobenzamide provides an oligosaccharide preparation containing reduced amounts of contaminants from plant cell wall polysaccharides. Such a preparation was also suitable for accurate qualitative and quantitative evaluation of the N-glycan content by mass spectrometry. Combining these approaches allows the profiling to be carried out from as low as 500 mg of fresh leaf material. We also demonstrated that collision-induced dissociation (CID) mass spectrometry in negative mode of N-glycans harboring alpha(1,3)- or alpha(1,6)-fucose residue on the proximal GlcNAc leads to specific fragmentation patterns, thereby allowing the discrimination of plant N-glycans from those arising from mammalian contamination.

Apoptosis as a possible mechanism of infertility inEchinococcus granulosus hydatid cysts

Echinococcus granulosus is a parasitic cestode causing hydatidosis in intermediate hosts (human and herbivorous). Most symptoms of the disease occur by the pressure exerted on viscera by cysts that are formed upon ingestion of the parasite eggs excreted by definitive hosts (canines). Protoscoleces, the developmental form of the parasite infective to definitive hosts, are formed in the germinal nucleated layer of fertile hydatid cysts. For unknown reasons, some cysts are unable to produce protoscoleces (infertile hydatid cysts). In this study, analysis of DNA fragmentation using TUNEL and agarose gel electrophoresis showed higher levels of apoptosis in infertile cysts as compared to fertile cysts. Additionally, caspase 3 was detected both in fertile and infertile cysts; the activity of this enzyme was found to be higher in infertile cysts. We conclude that apoptosis may be involved in hydatid cyst infertility. This is the first report on the presence of programmed cell death in E. granulosus.

Analytical strategies to investigate plant N-glycan profiles in the context of plant-made pharmaceuticals

Plants are attractive hosts for the production of recombinant proteins. However, their inability to process authentic human N-glycan structures imposes a major limitation on their use as expression systems for therapeutic products. Several strategies have emerged to engineer plant N-glycans into human-compatible molecules. In this context, fast and reliable analytical strategies for the identification of plant N-glycan profiles have been developed to define the N-glycosylation pathways of crops, to monitor the production of plant-made pharmaceuticals and to assess in planta remodelling strategies.

Toxic effects of dissolved heavy metals on Desulfovibrio vulgaris and Desulfovibrio sp. strains

Biological treatment of metal-containing wastewaters with sulphate-reducing bacteria (SRB) is an attractive technique for the bioremediation of this kind of medium. In order to design a suitable engineering process to address this environmental problem, it is crucial to understand the inhibitory effect of dissolved heavy metals on these bacteria. Batch studies were carried out to evaluate the toxic effects of several heavy metal ions [Cr(III), Cu(II), Mn(II), Ni(II) and Zn(II)] on two cultures of SRB (Desulfovibrio vulgaris and Desulfovibrio sp.). The experimental data indicate that SRB show different responses to each metal. At the highest metal concentration tolerated for each metal, the precipitation levels for D. vulgaris were as follows: 24.7%-15 ppm Cr(III), 45%-4 ppm Cu(II), 60%-10 ppm Mn(II), 96%-8.5 ppm Ni(II) and 9%-20 ppm Zn(II). The corresponding values for Desulfovibrio sp. were: 25.5%-15 ppm Cr(III), 71%-4 ppm Cu(II), 66.2%-10 ppm Mn(II), 96.1%-8.5 ppm Ni(II) and 93%-20 ppm Zn(II). Results obtained in batch studies will be taken into account for the subsequent design of a sulphate-reducing bioreactor to reduce levels of heavy metals present in different types of contaminated media.

Chemotherapy alternating gemcitabine and cisplatin concomitant with radiotherapy in locally advanced (LA) squamous cell carcinoma of the head and neck (SCCHN)

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Background: In the Pignon’s meta-analysis, the OS benefit was 8% with chemoradiation in LA SCCHN. Unfortunately it is still unclear what scheme is the best, cisplatin (CDDP) being the most widely used drug. Other drugs such as gemcitabine (GMZ) has promising results, although toxicity has been severe but tolerable. We have published an initial study using GMZ and radiotherapy (ann oncol. 2004;15:301). In the present study we wished to determine if a scheme in which GMZ is alternated with CDDP and concomitant radiotherapy reduced toxicity yet maintains our previously described therapeutic effectiveness. This is a preliminary report with a short follow-up period. Methods: Inclusion criteria: patients with SCCHN (EC: III, IVa and IVb ) or with recurring disease, and no sytemic metastases or patients rejection of surgery between 03/2003 and 09/2004. Chemotherapy scheme consisted of GMZ at 100 mg/m2 once a w, ws 1, 3, 5, 7 and CDDP at 50 mg/m2 once a w, ws 2, 4, y 6. Radiotherapy consisted of 2 Gy/day, for a total of 70 Gy during the 7 ws. Toxicity evaluation focused on mucositis, xerostomia, dysphagia y leukopenia. Results: 28 patients were treated. 7 (25%)/ stage III, 11 (39.3%) IVa, 10 (35.7%) IVb. The tumor sites distribution was as follows: 9 patients with oropharynx and larynx disease (32.1%), 6 patients with oral cavity disease (21.4%), 3 patients with paranasal sinus disease (10.7%), and 1 hypopharinx (3.5%). A CCR was observed in 21 patients (75%), a partial response was observed in 5 patients (17%). Organ preservation was achieved in 68% of the patients. Toxicity: mucositis Grade 3–4 was in 42% of patients, leucopenia grade III in 29%, dysphagia in 19% and xerostomia in 10%. 40%of the patients stopped treatment for one or two weeks due to toxicity without affecting the doses of both treatments. Conclusions: The scheme with alternating GMZ and CDDP concomitant with radiotherapy is safe and effective. We observed a lower incidence in mucositis and few systemic toxic effects. Our findings support further studies in which alternating chemotherapeutic schemes are utilized given that tumor response is increased without an increment in toxicity.

No significant financial relationships to disclose.

Phase II clinical trial preliminary report: Cetuximab, gemcitabine and simultaneous radiotherapy for locally advanced head and neck cancer: Preliminary report

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Background: Previous studies with cetuximab in SCCHN demonstrate to be clinically beneficial. In the present study we wished to evaluate the efficacy and safety of a chemotherapeutic scheme using gemcitabine, radiotherapy and cetuximab for SCCHN. Preliminary report of 20 of 40 enrolled patients into a phase II clinical trial. Methods: inclusion criteria; histological confirmation of epidermoid carcinoma, ages 18 to 70, K > 70%, normal renal, hepatic and haematologic functions, without previous treatment, surgically inoperable disease, or patients with operable disease that did not consent to surgery. All patients signed an informed consent form. Radiotherapy: 200 cGy/d/5/w until 70Gy were completed. Cetuximab: an initial dose of 400 mg/m2 one week prior to initiation of radiotherapy, followed by 250 mg/m2 weekly until completion of radiotherapy. Gemcitabine: 50 mg /m2 weeks 1–2, 4–5 and 7. Results: 20 patients were enrolled (16m/4f) from november of 2004 to november of 2005, (5 oral cavity, 5 oropharynx, 8 larynx, 1 hypopharynx and 1 paranasal sinus). Mean age 56 yrs (33–75). Tumor staging: 7/III, 8/IVa and 5/IVb. One female was excluded, 19 completed the study and were evaluated. GR 17/19 (89.5%), CR 13/17 (76.5%) and PR 4/17 (23.5%). 2/19 NR (10.5%). CR of the 1ary tumor 15/19 patients (78.9%); CR 6/11 patients with lymphatic disease at diagnosis (54.5%), PR 3/19 (27.3%). Toxicity: mucositis g/III-IV 8/19 patients; rash g/III 4 patients. 2/19 did not complete treatment with chemotherapy due to mucositis but did with radiotherapy. No relationship was found between clinical response and the severity of the rash. One patient developed leukopenia g/III. 4 patients developed disphagia g/II, one has not resolved after 8 month follow up. Xerostomia g/II was 7/19 patients. Dermatological toxicity resolved by the end of the treatment. Mean follow up: 6 months, 1 patient which did not respond died and 1 patient with a PR recurred. Conclusions: The scheme is safe and effective with tolerable toxicity. In our previously reported experience, the addition of cetuximab to gemcitabine and radiotherapy does not increment local toxicity, statistical validation of these findings require the completion of the 40 patient study.

No significant financial relationships to disclose.

Soft drink consumption and excess weight gain in Australian school students: results from the Nepean study

We studied the relation between soft drink/cordial (a sweet, flavoured, concentrated syrup that is mixed with water to taste), fruit juice/drink and milk consumption in mid-childhood, and body mass index (BMI) status in early adolescence in a contemporary Australian cohort. In 1996/7, 268 children (136 males) were recruited from western Sydney at baseline (mean+/-s.d.: 7.7+/-0.6 years), and at follow-up 5 years later (13.0+/-0.2 years). Height and weight were measured at both time periods and overweight and obesity defined using the International Obesity TaskForce criteria. Beverage consumption was calculated from a 3-day food record at baseline. Median carbohydrate intake from soft drink/cordial was 10 g higher (P=0.002) per day in children who were overweight/obese at follow-up compared to those who had an acceptable BMI at both baseline and follow-up. Intakes of soft drink/cordial in mid-childhood, but not fruit juice/fruit drink and milk, were associated with excess weight gain in early adolescence.

Localization, specific activity, and molecular forms of acetylcholinesterase in developmental stages of the cestode Mesocestoides corti

The nervous system of flatworms is quite simple although there is increasing evidence indicating that it is chemically complex. Studies of the nervous system in these animals have only been performed in the larval stage or in the adult worms, which are easy to obtain in nature, while the description of the nervous system in developing stages of these organisms is missing. Mesocestoides corti is a parasitic platyhelminth whose larvae can be induced in vitro to develop to adult, sexually mature worms, opening the possibility of studying the nervous system of a flatworm in different stages of development. Here, we describe the presence, activity, location, and molecular forms of acetylcholinesterase (AChE) in different stages of development of M. corti, from the larvae to adult forms of this endoparasite, obtained in in vitro cultures after induction of the larval stage with trypsin. Our results point to AChE as a molecular marker of the nervous system in platyhelminthes. The change in molecular forms of this enzyme and the increase in its activity during development from larvae to adult worm may reflect the presence of a more complex nervous system, necessary to adjust and coordinate the movement of a much bigger structure. A relationship between the development of the reproductive apparatus in segmented and adult worms with a more complex nervous system in these stages is also apparent. Finally, our study opens the possibility of applying anti-AChE as more effective therapeutic strategies against cestode parasites.

Cyclosporine A from a nonpathogenic Fusarium oxysporum suppressing Sclerotinia sclerotiorum

AIMS

To evaluate the antagonistic activity of Fusarium oxysporum nonpathogenic fungal strain S6 against the phytopathogenic fungus Sclerotinia sclerotiorum and to identify the antifungal compounds involved.

METHODS AND RESULTS

The antagonistic activity of Fusarium oxysporum strain S6 was determined in vitro by dual cultures. The metabolite responsible for the activity was isolated by chromatographic techniques, purified and identified by spectroscopic methods as cyclosporine A. The antifungal activity against the pathogen was correlated with the presence of this metabolite by a dilution assay and then quantified. Cyclosporine A caused both growth inhibition and suppression of sclerotia formation. In a greenhouse assay, a significant increase in the number of surviving soybean (Glycine max) plants was observed when S. sclerotiorum and F. oxysporum (S6) were inoculated together when compared with plants inoculated with S. sclerotiorum alone.

CONCLUSION

Fusarium oxysporum (S6) may be a good fungal biological control agent for S. sclerotiorum and cyclosporine A is the responsible metabolite involved in its antagonistic activity in vitro.

SIGNIFICANCE AND IMPACT OF THE STUDY

Cyclosporine A has not been previously described as an inhibitor of S. sclerotiorum. Its minimum inhibitory concentration (MIC) of 0.1 microg disc(-1) makes it suitable to use as a biofungicide. In vivo experiments showed that F. oxysporum (S6) is a good candidate for the biocontrol of S. sclerotiorum in soybean.

Plant-derived mouse IgG monoclonal antibody fused to KDEL endoplasmic reticulum-retention signal is N-glycosylated homogeneously throughout the plant with mostly high-mannose-type N-glycans

Plants are potential hosts for the expression of recombinant glycoproteins intended for therapeutic purposes. However, N-glycans of mammalian glycoproteins produced in transgenic plants differ from their natural counterparts. The use of the endoplasmic reticulum (ER)-retention signal has been proposed to restrict glycosylation of plantibodies to only high-mannose-type N-glycans. Furthermore, little is known about the influence of plant development and growth conditions on N-linked glycosylation. Here, we report a detailed N-glycosylation profiling study of CB.Hep1, a mouse IgG2b monoclonal antibody (mAb) against hepatitis B surface antigen (HBsAg) currently expressed in tobacco plants (Nicotiana tabacum L.). The KDEL ER-retention signal was fused to the C-terminal of both light and heavy chains. The structures of the N-linked glycans of this mAb produced in transgenic tobacco plants at various growth stages were analysed by high-performance liquid chromatography (HPLC) profiling techniques and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and compared with those of murine origin. The high-mannose-type oligosaccharides accounted for more than 80% of the total N-glycans, with Man7GlcNAc2 being the most abundant species. Some complex N-glycans bearing xylose and small amounts of oligosaccharides with both xylose and fucose were identified. No appreciable differences were detected when comparing glycosylation at different leaf ages, e.g. from seedling leaves up to 8 weeks old and top or basal leaves of mature plants, or between leaves, stems and whole plants. A strict retention of glycoproteins to ER by the use of the tetrapeptide KDEL was not sufficient, even though the majority of the resulting N-glycosylation was of the high-mannose type. It is highly likely to be dependent on other factors, which are most probably protein specific.

Influence of culture conditions on the N-glycosylation of a monoclonal antibody specific for recombinant hepatitis B surface antigen

MAbs (monoclonal antibodies) are becoming increasingly important as diagnostic tools for pharmaceutical biotechnology, and hence it is crucial that they are produced under controlled conditions to assure their consistency and reproducibility, not only in terms of protein sequence and bioactivity, but also in terms of post-translational modifications, e.g. for N-glycosylation. Hybridoma CB.Hep-1, which secretes an IgG2b mAb, was cultured in vivo in ascites and in vitro in static-flask, spinner-flask, dialysis-membrane and perfusion systems using protein-free, low-serum-containing medium (1% foetal-calf serum) and high-serum-containing medium (8% foetal-calf serum). These CB.Hep-1 mAbs were fully characterized, and insignificant differences in the affinity constant were observed. Glycosylation profiling was performed by labelling the N-glycans released by peptide N-glycosidase F with either of the fluorophore tags 8-aminonaphthalene-1,3,6-trisulphonic acid and 4-aminobenzoic acid. The mAb produced in vivo showed two major biantennary-complex-type N-glycans: monogalactosylated, core-fucosylated and agalactosylated, core-fucosylated. The mAbs produced in vitro in static flasks and spinner flasks were not significantly influenced by the serum content in the culture media and showed a higher degree of N-glycan galactosylation compared with those produced in mouse-ascites, hollow-fibre and membrane systems. The monogalactosylated, core-fucosylated structure was the most abundant N-glycan except for those produced in ascites and hollow fibres, where the agalactosylated, core-fucosylated glycoform was the major specie. MAbs produced in high-cellular-yield systems displayed greater galactosylation heterogeneity influenced by changes in culture media.

The cattle tick antigen, Bm95, expressed in Pichia pastoris contains short chains of N- and O-glycans

Bm95 is an antigen isolated from Boophilus microplus strains with low susceptibility to antibodies developed in cattle vaccinated with the recombinant Bm86 antigen (Gavac, HeberBiotec S.A., Cuba). It is a Bm86-like surface protein, which by similarity contains seven EGF-like domains and a lipid-binding GPI-anchor site at the C-terminal region. The primary structure of the recombinant (rBm95) protein expressed in Pichia pastoris was completely verified by LC/MS. The four potential glycosylation sites (Asn 122, 163, 329, and 363) are glycosylated partially with short N-glycans, from Man(5)GlcNAc(2) to Man(9)GlcNAc(2) of which, Man(8-9)GlcNAc(2) were the most abundant. O-Glycopeptides are distributed mostly towards the protein N-terminus. While the first N-glycosylated site (Asn(122)) is located between EGF-like domains 2 and 3, where the O-glycopeptides were found, two other N-glycosylated sites (Asn(329) and Asn(363)) are located between EGF-like domains 5 and 6, a region devoid of O-glycosylated Ser or Thr.

Inhibitory effects on esterase enzymes buche and ache in rainbow trout (Oncorhyncus mykiss) produced by the slow release insecticide chitosan diethyl phosphate

The study on the toxicity of chitosan diethyl phosphate (ChDP), a controlled release insecticide, on the activities of butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) in rainbow trout exposed to this pesticide was carried out. It was found that ChDP reduced BuChE activity in O. mykiss by a factor of eight at 6 days, with high fluctuation to the end of the exposition time at 12 days. The in vitro analysis of brain AChE treated with ChDP and Phenamiphos showed that it was competitively inhibited by both organophosphates. The values obtained for Km and Vmax for the AChE-ChDP (Km: 21.23 microM; Vmax: 43.10 micromol/min/g) and AChE-Phenamiphos (Km: 38.62 microM; Vmax: 38.91 micromol/min/g) systems were relatively low compared to values of the AChE (control) system (Km: 62.99 microM; Vmax: 63.29 micromol/min/g). Results reported in this study confirmed that chitosan diethyl phosphate performs similarly to organophosphate pesticides, producing inhibition in cholinesterases in rainbow trout.

Hypogalactosylation of serum IgG in patients with coeliac disease

Coeliac disease (CD) is described as an autoimmune enteropathy associated with the presence of IgG and IgA antigliadin and antitransglutaminase autoantibodies. While of diagnostic significance, the role of these autoantibodies in the immunopathogenesis of CD is elucidated. An inappropriate T cell immune response to gluten is also involved in the pathogenesis of CD, as evidenced by autoantibody switching. The N-glycans released from serum IgG of CD patients and three groups of healthy controls, of differing age ranges, were analysed by NH2-high performance liquid chromatography (HPLC). The fucosylated biantennary N- glycans were the most abundant neutral oligosaccharides; in particular, the agalacto form (G0F) showed a mean value of 42% (s.d. +/- 7.4), 30% (s.d. +/- 5.9), 26% (s.d. +/- 4.2) and 35% (s.d. +/- 6.8) for CD patients, healthy children, healthy adults under 40 and healthy adults over 40 years old, respectively. The ratio of asialo agalacto fucosylated biantenna to asialo monogalacto fucosylated biantenna (G0F)/(G1F) for CD patients showed a significant increase compared to healthy children (P < 0.0002), healthy adults under 40 (P < 0.0002) and healthy adults over 40 years old (P < 0.01). Hypogalactosylation was more pronounced for CD patients than for the patients with other autoimmune diseases such as rheumatoid arthritis or psoriatic arthritis.

Molecular characterization of the iron-hydroxamate uptake system in Staphylococcus aureus

To investigate iron uptake, a chromosomal locus containing three consecutive open reading frames, designated fhuC, fhuB, and fhuD, was identified in Staphylococcus aureus. Whereas the fhuC gene encodes an ATP-binding protein, fhuB and fhuD code for ferrichrome permeases and thus resemble an ATP-binding cassette transporter. A fhuB knockout mutant showed impaired uptake of iron bound to the siderophores but not of ferric chloride, suggesting that this operon is specific for siderophore-mediated iron uptake.