At 25 degrees C, the optimal temperature for growth of Rhizobium trifolii TA-1, extracellular and capsular polysaccharide (EPS and CPS) were the main carbohydrate products synthesized in mannitol-rich medium (10 g of mannitol and 1 g of glutamic acid per liter). In the same medium at 33 degrees C, EPS and CPS production was inhibited, and up to 3.9 g of cyclic beta-(1,2)-glucan was produced during an incubation period of 20 days with a total biomass of 0.55 g of protein. In a medium containing 50 g of mannitol and 10 g of glutamic acid per liter, high cell densities (3.95 g of protein) were obtained at 25 degrees C. This biomass excreted 10.9 g of cyclic beta-(1,2)-glucan within 10 days. Concomitantly, 4.8 g of EPS were synthesized, while CPS production was strongly suppressed. The excreted cyclic beta-(1,2)-glucans were neutral and had degrees of polymerization ranging from 17 to 25, with a degree of polymerization of 19 as the major glucan cycle.

Since dendritic cells (DC) participate in both innate and adaptive immunity, their survival and expansion is tightly controlled. Little is known about the mechanisms of DC apoptosis. PGE(2), an arachidonic acid metabolite, plays an essential role in DC migration. We propose a novel function for PGE(2) as a DC survival factor. Our studies demonstrate that PGE(2) protects DC in vitro against apoptosis induced by withdrawal of growth factors or ceramide. DC matured in conditions that inhibit endogenous PGE(2) release are highly susceptible to apoptosis and exogenous PGE(2) re-establishes the more resistant phenotype. The antiapoptotic effect is mediated through EP-2/EP-4 receptors and involves the PI3K ->> Akt pathway. PGE(2) leads to increased phosphorylation of Akt, protection against mitochondrial membrane compromise, and decreased caspase 3 activity. Macroarray data indicate that PGE(2) leads to the down-regulation of a number of proapoptotic molecules, i.e., BAD, several caspases, and granzyme B. In vivo, higher numbers of immature and Ag-loaded CFSE-labeled DC are present in the draining lymph nodes of mice inoculated with PGE(2) receptor agonists, compared with animals treated with ibuprofen or controls injected with PBS. This suggests that PGE(2) acts as an endogenous antiapoptotic factor for DC and raises the possibility of using PGE(2) agonists to increase the survival of Ag-loaded DC following in vivo administration.

Although prostaglandin E2 (PGE2) has been shown to be critical to hippocampal synaptic signaling and neuronal survival, it is still not clear which subtypes of PGE2 receptors (EPs) are expressed and how these EPs are regulated in the hippocampus. To address these questions, the expression of the EPs was profiled in the hippocampus. Messenger RNAs and proteins of the four receptors, EP 1-4, were detected both in the hippocampus and in the neocortex. EP 2 and EP 3 appeared in greater abundance, whereas EP 1 and EP 4 were barely detectable. EP 1, EP 2 and EP 4 were mainly colocalized with synaptophysin, suggesting the presence of EP 1, EP 2, and EP 4 in presynaptic terminals. It appeared that interleukin-1 beta increased the expression of EP 2 and EP 4 mRNAs. A blockade of synaptic transmission with either tetrodotoxin or MK-801 plus 6,7-dinitroquinoxaline-2,3-dione (DNQX) for 6 hr increased EP 3 and EP 4 mRNA, whereas high K(+) (90 mM) or 4-aminopyridine enhanced EP 2 and EP 4. The EP 1 level did not change significantly under these conditions. The expressions of EP 2, EP 4, and EP 3 were further elevated or reduced in neurons treated with high K(+) for 24 hr. However, mRNA of EP 3 was down-regulated in neurons treated with tetrodotoxin or MK-801 plus DNQX for 24 hr. In addition, both EP 2 and EP 4 mRNAs were up-regulated within 4 hr after high-frequency stimulation associated with long-term potentiation induction in hippocampal slices. Our results indicate that the four EPs are heterogeneously expressed in the hippocampus, and their expression is differentially regulated by neuronal activities, suggesting that EPs may actively participate in hippocampal synaptic transmission and plasticity.

1. The effect of beta-endorphin (beta-EP) and morphine sulfate (MS), in presence and absence of naloxone (NX), on chicken chorioallantoic membrane was studied as a function of blood vessel proliferation. 2. A 50% reduction in blood vessel proliferation occurred by 10 micrograms of beta-EP or by 5 micrograms of MS per egg compared to controls. 3. An individual dose, i.e. 5 micrograms of beta-EP, did not significantly inhibit blood vessel counts after initial 24 hr period of the drug application when given alone compared to inhibition occurring with combined use of NX. 4. NX (1 microgram) did not significantly reverse the angiostatic effects of MS (10 micrograms) or of beta-EP (5 micrograms). 5. The observed modulation of angiogenesis by opioids suggests involvement of beta-EP and MS in the proliferation of vascular endothelial cells. 6. This may be due to an effect of beta-EP and MS on cell-mediated immunity factors such as interferons, interleukins and prostaglandin E2.

OBJECTIVE

To investigate possible cardioprotective mechanisms of electroacupuncture (EA) at the Neiguan point and at the Lieque point in the presence of myocardial ischemia-reperfusion injury (MIRI).

METHODS

The changes in ventricular tissue Bax and Bcl-2 protein expression, malondialdehyde (MDA) content and glutathione peroxidase (GSH-PX) activity were examined, as well as beta-endorphin (beta-EP) con-tent in a rabbit model of MIRI. Four randomized groups were studied: sham, untreated MIRI, MIRI followed by EA at the Neiguan point, and MIRI followed by EA at the Lieque point. The MIRI model involved ligating the left anterior descending coronary artery for 30 min followed by a 60 min postischemia reperfusion period.

RESULTS

EA at the Neiguan point dramatically decreased the number of apoptotic cells and the content of beta-EP and MDA, and inhibited Bax protein expression while enhancing Bcl-2 expression and GSH-PX activity. Furthermore, EA enhanced Bcl-2 expression and GSH-PX activity. Lesser effects were elicited by EA at the Lieque point.

CONCLUSIONS

The cardioprotective effects of applying EA at the Neiguan point on MIRI include reducing apoptosis, regulating apoptosis- controlling genes, and decreasing myocardial MDA and beta-EP while enhancing GSH-PX activity.

Bacterial microcompartments (BMCs) are proteinaceous organelles used by a broad range of bacteria to segregate and optimize metabolic reactions. Their functions are diverse, and can be divided into anabolic (carboxysome) and catabolic (metabolosomes) processes, depending on their cargo enzymes. The assembly pathway for the β-carboxysome has been characterized, revealing that biogenesis proceeds from the inside out. The enzymes coalesce into a procarboxysome, followed by encapsulation in a protein shell that is recruited to the procarboxysome by a short (∼17 amino acids) extension on the C-terminus of one of the encapsulated proteins. A similar extension is also found on the N- or C-termini of a subset of metabolosome core enzymes. These encapsulation peptides (EPs) are characterized by a primary structure predicted to form an amphipathic α-helix that interacts with shell proteins. Here, we review the features, function and widespread occurrence of EPs among metabolosomes, and propose an expanded role for EPs in the assembly of diverse BMCs.

This systematic review aimed to determine whether the risk of extrapyramidal side effects (EPS) differed between antipsychotic drugs used in first episode psychosis (FEP). We identified 11 RCTs comparing two or more antipsychotics in FEP and reporting on EPS. All trials assessed one or more second generation antipsychotics (SGAs), one assessed chlorpromazine, one zuclopenthixol and seven trials assessed haloperidol. Assessment and reporting of EPS varied. Compared with one or more SGA comparators, haloperidol was associated with significantly higher rates/severity of parkinsonism (seven trials) and akathisia (six trials) and greater use of anticholinergics (five trials) and beta-blockers (two trials). Two trials with low-dose haloperidol (≤ 4 mg) showed significantly worse EPS outcomes versus a SGA. Two of four long-term haloperidol trials (≥ 1 year) found a higher dyskinesia-risk with haloperidol versus olanzapine and risperidone respectively; the remaining two trials found no difference (various SGA comparators). There was an EPS advantage for clozapine versus chlorpromazine (one trial) and risperidone versus zuclopenthixol (one trial). There was little evidence of EPS-differences between SGAs, possibly reflecting use of low doses. We conclude that SGAs offer an EPS advantage over FGAs in FEP though the evidence largely relates to comparisons with haloperidol. Standardized assessment and reporting of EPS would assist future research.

Chordoid meningioma is a rare variant of meningioma with histological features resembling those of chordoma. This tumor has a great risk of recurrence and aggressive growth (WHO grade II). This study was done to document the clinical and pathological features of ten patients with chordoid meningioma who submitted to surgery at the National Institute of Neurology and Neurosurgery in Mexico City. Clinical, histological and immunohistochemical features were examined. The age range was from 30 to 67 years old (mean, 34.2 years). Seven patients were female and three male. The duration of symptoms varied from 3.5 months to 5 years (mean, 14.1 months). No systemic symptoms were noted. The tumor was localized in eight cases in the supratentorial compartments. Histologically, the tumors were characterized by strands and cords of meningothelial cells arranged in a mucinous stroma. Two of the ten tumors showed metaplasic changes, and seven showed brain invasion. Tumor cells demonstrated CK7, EMA and focal S-100 protein and Ep-CAM. Cytokeratin AE1/AE3, GFAP and synaptophysin were negative. The MIB-1 proliferative index was from 6 to 9% (mean 7.8). PCNA Li was 6 to 20% (mean, 14), and microvascular density was 6-16 (mean, 14.5). The mean rate of the MIB-1 labeling index in recurrences was 7.1% versus 6.33% for no tumor recurrence. Chordoid meningioma, World Health Organization grade II, is an uncommon variant of meningioma with a propensity for aggressive behavior and increased likelihood of recurrence. Chordoid meningiomas are predominantly tumors of young adults with a predilection for the supratentorial location. Intraventricular location and absence of systemic manifestations, despite the presence of abundant B-lymphocytes, mast cells and low MIB-1 LI, are some of the interesting findings in the present series that need further study. Hence, a larger number of cases with adequate follow-up data need to be studied further to establish the clinical relevance of this variant.

BACKGROUND

Previous studies have shown that individuals withdrawn from chronic opiate administration undergo substantial elevations of cortisol levels with blunted corticotropin (ACTH) rhythms and that these changes persist beyond the 7-10 days of acute withdrawal symptoms. However, there are no published studies of changes in expression of clock genes or of other neuropeptides related to circadian-rhythm regulation, which may influence relapse susceptibility.

METHODS

Blood samples were collected from 8 healthy control subjects and 16 heroin addicts during pharmacologically unassisted withdrawal on the 3rd, 10th, and 30th days of abstinence at 3-hour intervals for 24 hours. Outcome measures were the relative expression of clock gene mRNA (hperiod1, hperiod2, hclock) and the levels of serum cortisol, plasma ACTH, beta-endorphin (beta-EP), leptin, neuropeptide Y, interleukin-2 (IL-2), and tumor necrosis factor (TNF) in these subjects.

RESULTS

Compared with healthy volunteers, abstinent addicts showed disruptions in diurnal rhythms of hPER1 and hPER2 mRNA expression, along with disruptions in diurnal rhythms of cortisol, ACTH, beta-endorphin, leptin, and IL-2 release. Several of these disruptions (hPER1, hPER2, ACTH, beta-endorphin, and IL-2) persisted for the 30-day testing period, as did elevation of 24-hour levels of cortisol and decreases in 24-hour IL-2 and TNF levels.

CONCLUSIONS

These prolonged neurobiological changes may play a role in protracted opiate withdrawal symptoms and contribute to relapse vulnerability.

BACKGROUND

In 2009, we investigated the conformance of 8 hemoglobin A(1c) (Hb A(1c)) point-of-care (POC) instruments. Since then, instruments have improved and new devices are available on the market. In this second study, we evaluated the performance of DCA Vantage, Afinion, InnovaStar, Quo-Lab, Quo-Test, Cobas BB-analyst Hb A(1c) POC instruments.

METHODS

Clinical and Laboratory Standards Institute protocols EP-5 and EP-9 were applied to investigate imprecision, accuracy, and bias. We assessed bias using the mean of 3 certified secondary reference measurement procedures (SRMPs). Assay conformance with the National Glycohemoglobin Standardization Program (NGSP) certification criteria was also evaluated. Interference of common Hb variants was investigated for methods that could work with hemolysed material.

RESULTS

The total CVs for all instruments, except for the DCA Vantage at a high Hb A(1c) value, were ≤3.1% in SI units and ≤2.1% in Diabetes Control and Complications Trial (DCCT) units. Afinion, DCA Vantage, <em>B</em>-analyst, and Cobas <em>B</em>101 instruments passed the NGSP criteria with 2 different reagent lot numbers. Quo-Test, Quo-Lab, and InnovaStar instruments had a negative bias compared to the mean of the 3 SRMPs and failed NGSP criteria. Most of the common Hb variants did not interfere with the investigated instruments, except Hb AE for the Cobas <em>B</em>101.

CONCLUSIONS

Afinion, DCA Vantage, Cobas BB-analyst instruments met the generally accepted performance criteria for Hb A(1c). Quo-Test, Quo-Lab, and InnovaStar met the criteria for precision but not for bias. Proficiency testing should be mandated for users of Hb A1c POC assays to ensure quality.

In inflammatory diseases, strong release of elastinolytic proteases results in elastin fiber degradation generating elastin peptides (EPs). Chemotactic activity for inflammatory cells was, among wide range of properties, the former identified biological activity exerted by EPs. Recently, we demonstrated the ability of EPs to favor a Th1 cytokine (IL-2, IFN-gamma) cell response in lymphocytes and to regulate IL-1beta expression in melanoma cells. We hypothesized that EPs might also influence inflammatory cell properties by regulating cytokine expression by these cells. Therefore, we investigated the influence of EPs on inflammatory cytokine synthesis by human monocytes. We evidenced that EPs down-regulated both at the mRNA and protein levels the proinflammatory TNF-alpha, IL-1beta, and IL-6 expression in LPS-activated monocytes. Such negative feedback loop could be accounted solely for EP-mediated effects on proinflammatory cytokine production because EPs did not affect anti-inflammatory IL-10 or TGF-beta secretion by LPS-activated monocytes. Furthermore, we demonstrated that EP effect on proinflammatory cytokine expression by LPS-stimulated monocytes could not be due either to a decrease of LPS receptor expression or to an alteration of LPS binding to its receptor. The inhibitory effects of EPs on cytokine expression were found to be mediated by receptor (spliced galactosidase) occupancy, as being suppressed by lactose, and to be associated with the decrease of NF-kappaB-DNA complex formation. As a whole, these results demonstrated that EP/spliced galactosidase interaction on human monocytes down-regulated NF-kappaB-dependent proinflammatory cytokine expression and pointed out the critical role of EPs in the regulation of inflammatory response.

Immunohistochemical evidence has indicated that beta-endorphin (beta EP) is present in the Leydig cells of fetal, neonatal, and adult mice and hamsters. In vivo experiments suggest that hCG and/or testosterone may increase the synthesis and release of the peptide from the Leydig cell compartment. Since cultured fetal Leydig cells have considerable potential for long term studies and elucidation of trophic hormone actions in vitro, we evaluated beta EP production in this system. Fetal Leydig cells were maintained in culture for 5 days in medium with 1 microgram ovine LH added every third day in the presence or absence of inhibitors of cholesterol (aminoglutethimide) or pregnenolone metabolism (cyanoketone and spironolactone), or known regulators of beta EP production [dexamethasone (DEX)]. Media were assayed for testosterone and beta EP by RIA methods. Beta EP accumulation over 3 and 5 days was markedly increased by inhibitors of steroid biosynthesis (1.5-fold) and reduced by DEX only after treatment for 5 days (by 50%). Acute hCG stimulation significantly increased beta EP levels by 5- to 9-fold in all conditions tested. Inhibition of Leydig cell steroid biosynthesis markedly increased basal and hCG-stimulated beta EP output (by 150-200%). In contrast, DEX reduced basal and hCG-stimulated beta EP production (by approximately 50%). HPLC analysis of cultured pooled media revealed that the beta EP immunoreactivity eluted at the retention time of authentic rat beta EP. The pattern of beta EP stimulation was not reflected by testosterone levels that were low or undetectable in controls and under conditions in which spironolactone/cyanoketone or aminoglutethimide were present; most importantly, inhibition of steroid biosynthesis markedly increased beta EP levels. In addition, beta EP (10(-7) M) did not affect testosterone production, and opiate binding was not detected on Leydig cells. The lack of degradation of this opioid peptide in the fetal cultures contrasted with results from adult cultures and provided an ideal system for studies of the regulation of this peptide in Leydig cells. These results demonstrate that beta EP is released from fetal Leydig cells in culture and that acute stimulation of Leydig cells by hCG can enhance beta EP secretion. These changes are not mediated by testosterone. In contrast, testosterone or its metabolites may exert negative autocrine modulation of beta EP production.(ABSTRACT TRUNCATED AT 400 WORDS)

Extracellular polymeric substances (EPS) play an important role in cell aggregation, cell adhesion, and biofilm formation, and protect cells from a hostile environment. The EPS was isolated by trichloroacetic acid/ethanol extraction from broth culture of a marine bacterium isolate. The EPS was composed of glucose and galactose as determined by HPLC and TLC; the protein content was on average 15 +/- 5% of EPS dry mass. The solution structure of EPS at different values of pH was revealed by small-angle x-ray scattering. Scattering curves of EPS solutions (0.4%, w/v) consistently showed two nearly linear log-log regions with slopes a and b in the q-ranges from 0.06 nm(-1) to 0.26 nm(-1), and from 0.27 nm(-1) to 0.88 nm(-1), respectively. Slope a was sensitive to pH changes whereas slope b was not. The observed sensitivity to pH was not a consequence of ionic strength variation with pH, as checked by salt addition. The pH variation causes major rearrangements of EPS structure mainly at length scales above 24 nm. To get a better understanding of the pH effect on EPS structure, the original model proposed by Geissler was refined into a mathematical model that enabled fitting of the experimental scattering curves in the pH range from 0.7 to 11.0. The model describes EPS structure as a network of randomly coiled polymeric chains with denser domains of polymeric chains. The results obtained from the model indicate that dense domains increase in average size from 19 nm at pH 11.0 to 52 nm at pH 0.7. The average distance between the polysaccharide chains at pH 0.7 was 2.3 nm, which indicates a compact EPS structure. Swelling was found to be at a maximum around pH = 8.8, where the average distance between the chains was 4.8 nm.

Cost estimates for developing new molecular entities (NME) are reaching non-sustainable levels and coupled with increasing regulatory requirements and oversight have led many pharmaceutical sponsors to divest their anti-microbial development portfolios [Projan SJ: Why is big Pharma getting out of anti-bacterial drug discovery?Curr Opin Microbiol 2003, 6:427-430] [Spellberg B, Powers JH, Brass EP, Miller LG, Edwards JE, Jr: Trends in antimicrobial drug development: implications for the future.Clin Infect Dis 2004, 38:1279-1286]. Operational issues such as study planning and execution are significant contributors to the overall cost of drug development that can benefit from the leveraging of pre-randomization data in an evidence-based approach to protocol development, site selection and patient recruitment. For non-NME products there is even greater benefit from available data resources since these data may permit smaller and shorter study programs. There are now many available open source intelligence (OSINT) resources that are being integrated into drug development programs, permitting an evidence-based or 'operational epidemiology' approach to study planning and execution.

OBJECTIVE

To investigate the expression pattern of epithelial cell adhesion molecule (Ep-CAM) on normal and malignant colon tissues to evaluate its diagnostic and therapeutic significance.

METHODS

cDNA encoding Ep-CAM extracellular domain was cloned by reverse transcription-polymerase chain reaction (RT-PCR) from excised malignant colon tissues and inserted into a glutathione S-transferase (GST)-tagged vector. Ep-CAM-GST fusion protein was induced by isopropyl-beta-D-thiogalactopyranoside (IPTG) and purified with glutathione-sepharose. The Ep-CAM-GST fusion protein was mixed with Freund's adjuvant and Balb/c mice were immunized with it. Sp2/0 myeloma cells were fused with the spleen cells of the immunized mice. After having selected by indirect ELISA, the anti-Ep-CAM monoclonal antibodies (MAbs) were generated and the corresponding ascites were obtained. Finally, the human colon carcinoma tissue array prepared from seventy individual patients was stained with the anti-Ep-CAM MAbs.

RESULTS

The isolated Ep-CAM cDNA sequence was identical to the data in GenBank. The expressed fusion protein was almost soluble and had a molecular weight (MW) of 53 ku. Four MAbs against Ep-CAM were obtained and designated as FMU-EpEpEpEpEpEp-CAM on Colo205 and SW480 cells, and all of them could be used for immunohistochemical staining of tissue sections. It was found that Ep-CAM was distributed differently in normal and various malignant colon tissues, including squamous cell carcinoma, signet-ring cell carcinoma and adenocarcinoma. In normal colon gland epithelia, Ep-CAM antigen was mainly distributed on the basolateral membrane and in the region between the basolateral membrane and the cytoplastic part near the nuclei, whereas the expression pattern of colon malignancies was mainly on the whole surface of epithelia and the expression was much higher than the normal colon tissues. The staining pattern of tissue array showed in adenocarcinoma and papillary adenocarcinoma, and the expression of Ep-CAM was increased from grade I to grade III.

CONCLUSIONS

MAbs against Ep-CAM might be useful for research on the structure and function of Ep-CAM and may have diagnostic and therapeutic value to various colon carcinomas.

Prostaglandin (PG) E(2) (PGE(2)) is a potent prostanoid derived from arachidonic which can interact with EP(1), EP(2), EP(3) and EP(4) prostanoid receptor subtypes. Recombinant human EP(4) receptors expressed in human embryonic kidney (HEK-293) cells were evaluated for their binding characteristics using [(3)H]-PGE(2) and a broad panel of natural and synthetic prostanoids in order to define their pharmacological properties. [(3)H]-PGE(2) binding was optimal in 2-[N-Morpholino]ethanesulphonic acid (MES) buffer (pH 6.0) yielding 98+/-0.7% specific binding. The receptor displayed high affinity (K(d)=0.72+/-0.12 nM; n=3) for [(3)H]-PGE(2) and interacted with a saturable number of binding sites (B(max)=6.21+/-0.84 pmol mg(-1) protein). In competition studies, PGE(2) (K(i)=0.75+/-0.03 nM; n=12) and PGE(1) (K(i)=1.45+/-0.24 nM; n=3) displayed high affinities, as did two derivatives of PGE(1), namely 11-deoxy-PGE(1) (K(i)=1.36+/-0.34 nM) and 13,14-dihydro-PGE(1) (K(i)=3.07+/-0.29 nM). Interestingly, synthetic DP receptor-specific agonists such as BW245C (K(i)=64.7+/-1.0 nM; n=3) and ZK118182 (K(i)=425+/-42 nM; n=4), and the purported EP(3) receptor-specific ligand enprostil (K(i)=43.1+/-4.4 nM), also displayed high affinity for the EP(4) receptor. Two known EP(4) receptor antagonists were weak inhibitors of [(3)H]-PGE(2) binding akin to their known functional potencies, thus: AH23848 (K(i)=2690+/-232 nM); AH22921 (K(i)=31,800+/-4090 nM). These studies have provided a detailed pharmacological characterization of the recombinant human EP(4) receptor expressed in HEK-293 cells.

The purpose of this study was to investigate a possible relation between resistance to bile salts and low pH with exopolysaccharide (EPS) producing of Bifidobacterium spp. In this study, a total of 31 Bifidobacterium spp. were isolated from breast fed infants feces and breast milk samples. As a result of the identification tests, isolates were identified as Bifidobacterium breve (15 strains), B. bifidum (11 strains), B. pseudocatenulatum (3 strains) and B. longum (2 strains). Bifidobacterium spp. were determined exopolysaccharide (EPS) production. EPS productions observed at chance rations (38.00-97.64 mg/l) among of Bifidobacterium spp. Furthermore, Bifidobacterium spp. were determined resistance to bile salts and low pH. Positive correlations between production of exopolysaccharide and resistance to bile salts (p<0.01) or low pH (p<0.01) were found Bifidobacterium spp. This investigation showed that high EPS production of Bifidobacteria may be important in the selection of probiotic strains for resistance to bile salts and low pH.

Prostaglandin E2 is a potent endogenous molecule that binds to four different G-protein-coupled receptors: EPEP modulators required for subtype-selective activity, as well as the structural requirements for improved pharmacokinetic parameters. Novel EP receptor subtype selective agonists and antagonists appear to be valuable drug candidates in the therapy of many pathophysiological states, including ulcerative colitis, glaucoma, bone healing, B cell lymphoma, neurological diseases, among others, which have been studied in vitro, in vivo and in early phase clinical trials.

Probiotics, prebiotics and synbiotics are frequently-used components for the elaboration of functional food. Currently, most of the commercialized probiotics are limited to a few strains of the genera Bifidobacteria, Lactobacillus and Streptococcus, most of which produce exopolysaccharides (EPS). This suggests that the beneficial properties of these microorganisms may be related to the biological activities of these biopolymers. In this work we report that a 2-substituted-(1,3)-β-d-glucan of non-dairy bacterial origin has a prebiotic effect on three probiotic strains. Moreover, the presence of this β-d-glucan potentiates in vitro adhesion of the probiotic Lactobacillus plantarum WCFS1 to human intestinal epithelial cells.

Xylella fastidiosa is a phytopathogen that causes diseases in different plant species. The development of disease symptoms is associated to the blockage of the xylem vessels caused by biofilm formation. In this study, we evaluated the sensitivity of biofilm and planktonic cells to copper, one of the most important antimicrobial agents used in agriculture. We measured the exopolysaccharides (EPS) content in biofilm and planktonic cells and used real-time reverse transcription polymerase chain reaction to evaluate the expression of the genes encoding proteins involved in cation/multidrug extrusion (acrA/B, mexE/czcA, and metI) and others associated with different copper resistance mechanisms (copB, cutA1, cutA2, and cutC) in the X. fastidiosa biofilm formed in two different media. We confirmed that biofilms are less susceptible to copper than planktonic cells. The amount of EPS seems to be directly related to the resistance and it varies according to the media where the cells are grown. The same was observed for gene expression. Nevertheless, some genes seem to have a greater importance in biofilm cells resistance to copper. Our results suggest a synergistic effect between diffusion barriers and other mechanisms associated with bacterial resistance in this phytopathogen. These mechanisms are important for a bacterium that is constantly under stress conditions in the host.

HrpN(EP), from the gram-negative pathogen, Erwinia pyrifoliae, is a member of the harpin group of proteins, inducing pathogen resistance and hypersensitive cell death in plants. When the hrpN(EP) gene driven by the OsCc1 promoter was introduced into tobacco plants via Agrobacterium-mediated transformation, their resistance to the necrotrophic fungal pathogen, Botrytis cinerea, increased. Resistance to B. cinerea was correlated with enhanced induction of SA-dependent genes such as PR-1a, PR2, PR3 and Chia5, of JA-dependent genes such as PR-1b, and of genes related to ethylene production, such as NT-EFE26, NT-1A1C, DS321, NT-ACS1 and NT-ACS2. However the expression of NPR1, which is thought to be essential for multiple-resistance, did not increase. Since the pattern of expression of defense-related genes in hrpN(EP)-expressing tobacco differed from that in plants expressing hpaG(Xoo) from Xanthomonas oryzae pv. Oryzae, these results suggest that different harpins can affect the expression of different defense-related genes, as well as resistance to different plant pathogens.

The entomopathogen Bacillus thuringiensis produces dense biofilms under various conditions. Here, we report that the transition phase regulators Spo0A, AbrB and SinR control biofilm formation and swimming motility in B. thuringiensis, just as they control biofilm formation and swarming motility in the closely related saprophyte species B. subtilis. However, microarray analysis indicated that in B. thuringiensis, in contrast to B. subtilis, SinR does not control an eps operon involved in exopolysaccharides production, but regulates genes involved in the biosynthesis of the lipopeptide kurstakin. This lipopeptide is required for biofilm formation and was previously shown to be important for survival in the host cadaver (necrotrophism). Microarray analysis also revealed that the SinR regulon contains genes coding for the Hbl enterotoxin. Transcriptional fusion assays, Western blots and hemolysis assays confirmed that SinR controls Hbl expression, together with PlcR, the main virulence regulator in B. thuringiensis. We show that Hbl is expressed in a sustained way in a small subpopulation of the biofilm, whereas almost all the planktonic population transiently expresses Hbl. The gene coding for SinI, an antagonist of SinR, is expressed in the same biofilm subpopulation as hbl, suggesting that hbl transcription heterogeneity is SinI-dependent. B. thuringiensis and B. cereus are enteric bacteria which possibly form biofilms lining the host intestinal epithelium. Toxins produced in biofilms could therefore be delivered directly to the target tissue.

Cyanobacterial organic matter excretion is crucial to carbon cycling in many microbial communities, but the nature and bioavailability of this C depend on unknown physiological functions. Cyanobacteria-dominated hypersaline laminated mats are a useful model ecosystem for the study of C flow in complex communities, as they use photosynthesis to sustain a more or less closed system. Although such mats have a large C reservoir in the extracellular polymeric substances (EPSs), the production and degradation of organic carbon is not well defined. To identify extracellular processes in cyanobacterial mats, we examined mats collected from Elkhorn Slough (ES) at Monterey Bay, California, for glycosyl and protein composition of the EPS. We found a prevalence of simple glucose polysaccharides containing either α or β (1,4) linkages, indicating distinct sources of glucose with differing enzymatic accessibility. Using proteomics, we identified cyanobacterial extracellular enzymes, and also detected activities that indicate a capacity for EPS degradation. In a less complex system, we characterized the EPS of a cyanobacterial isolate from ES, ESFC-1, and found the extracellular composition of biofilms produced by this unicyanobacterial culture were similar to that of natural mats. By tracing isotopically labeled EPS into single cells of ESFC-1, we demonstrated rapid incorporation of extracellular-derived carbon. Taken together, these results indicate cyanobacteria reuse excess organic carbon, constituting a dynamic pool of extracellular resources in these mats.

BACKGROUND

The activity of gelatinase, matrix metalloproteinase-2, in effluent was increased in peritoneal dialysis patients with encapsulated peritoneal sclerosis (EPS) and in chlorhexidine gluconate-induced peritoneal sclerosing (PS) animal models. The objective of the present study was to investigate the effect of matrix metalloproteinase inhibitor (ONO-4817), an anticancer agent with anti-angiogenesis and anti-infiltration effects, on the development of peritoneal fibrosis in chlorhexidine gluconate-induced PS rats.

METHODS

Forty-five Sprague-Dawley (S-D) rats were intraperitoneally injected with saline as control (n = 15) or with chlorhexidine gluconate (CH) (1.5 ml/100 g) in the CH group (n = 15). ONO-4817 (5 mg/rat) was administered intravenously to CH rats (the ONO-4817 group, n = 15) from initiation to the end of the study. After 22 days of ONO-4817 administration, the rats were sacrificed and the parietal peritoneum was harvested. The gene expressions of transforming growth factor-beta (TGF-beta), alpha-smooth muscle actin (alpha-SMA) and type I collagen in the peritoneum were analysed by the reverse transcription-polymerase chain reaction (RT-PCR). Peritoneal tissues were also evaluated immunohistologically.

RESULTS

ONO-4817 significantly inhibited thickening of the submesothelial layer and accumulation of type I collagen in the peritoneum. ONO-4817 also prevented increases of the number of macrophages and blood vessels. The expressions of TGF-beta, alpha-SMA and type I collagen in the peritoneum were markedly suppressed in ONO-4817-treated rats.

CONCLUSIONS

It appears that the administration of the MMP inhibitor ONO-4817 might be a new approach to the amelioration of PS.