Comparison of lipooligosaccharides from human challenge strains of Neisseria gonorrhoeae

The alarming rise of antibiotic resistance and the emergence of new vaccine technologies have increased the focus on vaccination to control gonorrhea. Neisseria gonorrhoeae strains FA1090 and MS11 have been used in challenge studies in human males. We used negative-ion MALDI-TOF MS to profile intact lipooligosaccharide (LOS) from strains MS11mkA, MS11mkC, FA1090 A23a, and FA1090 1-81-S2. The MS11mkC and 1-81-S2 variants were isolated from male volunteers infected with MS11mkA and A23a, respectively. LOS profiles were obtained after purification using the classical phenol water extraction method and by microwave-enhanced enzymatic digestion, which is more amenable for small-scale work. Despite detecting some differences in the LOS profiles, the same major species were observed, indicating that microwave-enhanced enzymatic digestion is appropriate for MS studies. The compositions determined for MS11mkA and mkC LOS were consistent with previous reports. FA1090 is strongly recognized by mAb 2C7, an antibody-binding LOS with both α- and β-chains if the latter is a lactosyl group. The spectra of the A23a and 1-81-S2 FA1090 LOS were similar to each other and consistent with the expression of α-chain lacto-N-neotetraose and β-chain lactosyl moieties that can both be acceptor sites for sialic acid substitution. 1-81-S2 LOS was analyzed after culture with and without media supplemented with cytidine-5'-monophosphate N-acetylneuraminic acid (CMP-Neu5Ac), which N. gonorrhoeae needs to sialylate its LOS. LOS sialylation reduces the infectivity of gonococci in men, although it induces serum resistance in serum-sensitive strains and reduces killing by neutrophils and antimicrobial peptides. The infectivity of FA1090 in men is much lower than that of MS11mkC, but the reason for this difference is unclear. Interestingly, some peaks in the spectra of 1-81-S2 LOS after bacterial culture with CMP-Neu5Ac were consistent with disialylation of the LOS, which could be relevant to the reduced infectivity of FA1090 in men and could have implications regarding the phase variation of the LOS and the natural history of infection.

Capture, Release, and Identification of Newly Synthesized Proteins for Improved Profiling of Functional Translatomes

New protein synthesis is regulated both at the level of mRNA transcription and translation. RNA-Seq is effective at measuring levels of mRNA expression, but techniques to monitor mRNA translation are much more limited. Previously, we reported results from O-propargyl-puromycin (OPP) labeling of proteins undergoing active translation in a 2-h time frame, followed by biotinylation using click chemistry, affinity purification, and on-bead digestion to identify nascent proteins by mass spectrometry (OPP-ID). As with any on-bead digestion protocol, the problem of nonspecific binders complicated the rigorous categorization of nascent proteins by OPP-ID. Here, we incorporate a chemically cleavable linker, Dde biotin-azide, into the protocol (OPP-ID_CL) to provide specific release of modified proteins from the streptavidin beads. Following capture, the Dde moiety is readily cleaved with 2% hydrazine, releasing nascent polypeptides bearing OPP plus a residual C₃H₈N₄ tag. When results are compared side by side with the original OPP-ID method, change to a cleavable linker led to a dramatic reduction in the number of background proteins detected in controls and a concomitant increase in the number of proteins that could be characterized as newly synthesized. We evaluated the method's ability to detect nascent proteins at various submilligram protein input levels and showed that, when starting with only 100 μg of protein, ∼1500 nascent proteins could be identified with low background. Upon treatment of K562 cells with MLN128, a potent inhibitor of the mammalian target of rapamycin, prior to OPP treatment, we identified 1915 nascent proteins, the majority of which were downregulated upon inhibitor treatment. Repressed proteins with log2 FC <-1 revealed a complex network of functionally interacting proteins, with the largest cluster associated with translational initiation. Overall, incorporation of the Dde biotin-azide cleavable linker into our protocol has increased the depth and accuracy of profiling of nascent protein networks.

Regulation of eIF4E guides a unique translational program to control erythroid maturation

Translation control is essential in balancing hematopoietic precursors and differentiation; however, the mechanisms underlying this program are poorly understood. We found that the activity of the major cap-binding protein eIF4E is unexpectedly regulated in a dynamic manner throughout erythropoiesis that is uncoupled from global protein synthesis rates. Moreover, eIF4E activity directs erythroid maturation, and increased eIF4E expression maintains cells in an early erythroid state associated with a translation program driving the expression of PTPN6 and Igf2bp1. A cytosine-enriched motif in the 5' untranslated region is important for eIF4E-mediated translation specificity. Therefore, selective translation of key target genes necessary for the maintenance of early erythroid states by eIF4E highlights a unique mechanism used by hematopoietic precursors to rapidly elicit erythropoietic maturation upon need.

Predominant phosphorylation patterns in Neisseria meningitidis lipid A determined by top-down MS/MS

Among the virulence factors in Neisseria infections, a major inducer of inflammatory cytokines is the lipooligosaccharide (LOS). The activation of NF-κB via extracellular binding of LOS or lipopolysaccharide (LPS) to the toll-like receptor 4 and its coreceptor, MD-2, results in production of pro-inflammatory cytokines that initiate adaptive immune responses. LOS can also be absorbed by cells and activate intracellular inflammasomes, causing the release of inflammatory cytokines and pyroptosis. Studies of LOS and LPS have shown that their inflammatory potential is highly dependent on lipid A phosphorylation and acylation, but little is known on the location and pattern of these posttranslational modifications. Herein, we report on the localization of phosphoryl groups on phosphorylated meningococcal lipid A, which has two to three phosphate and zero to two phosphoethanolamine substituents. Intact LOS with symmetrical hexa-acylated and asymmetrical penta-acylated lipid A moieties was subjected to high-resolution ion mobility spectrometry MALDI-TOF MS. LOS molecular ions readily underwent in-source decay to give fragments of the oligosaccharide and lipid A formed by cleavage of the ketosidic linkage, which enabled performing MS/MS (pseudo-MS³). The resulting spectra revealed several patterns of phosphoryl substitution on lipid A, with certain species predominating. The extent of phosphoryl substitution, particularly phosphoethanolaminylation, on the 4'-hydroxyl was greater than that on the 1-hydroxyl. The heretofore unrecognized phosphorylation patterns of lipid A of meningococcal LOS that we detected are likely determinants of both pathogenicity and the ability of the bacteria to evade the innate immune system.

Familial Adenomatous Polyposis Syndrome: An Update and Review of Extraintestinal Manifestations

CONTEXT.—

Familial adenomatous polyposis (FAP) is a rare genetic disorder with autosomal dominant inheritance, defined by numerous adenomatous polyps, which inevitably progress to colorectal carcinoma unless detected and managed early. Greater than 70% of patients with this syndrome also develop extraintestinal manifestations, such as multiple osteomas, dental abnormalities, and a variety of other lesions located throughout the body. These manifestations have historically been subcategorized as Gardner syndrome, Turcot syndrome, or gastric adenocarcinoma and proximal polyposis of the stomach. Recent studies, however, correlate the severity of gastrointestinal disease and the prominence of extraintestinal findings to specific mutations within the adenomatous polyposis coli gene (APC), supporting a spectrum of disease as opposed to subcategorization. Advances in immunohistochemical and molecular techniques shed new light on the origin, classification, and progression risk of different entities associated with FAP.

OBJECTIVE.—

To provide a comprehensive clinicopathologic review of neoplastic and nonneoplastic entities associated with FAP syndrome, with emphasis on recent developments in immunohistochemical and molecular profiles of extraintestinal manifestations in the thyroid, skin, soft tissue, bone, central nervous system, liver, and pancreas, and the subsequent changes in classification schemes and risk stratification.

DATA SOURCES.—

This review will be based on peer-reviewed literature and the authors' experiences.

CONCLUSIONS.—

In this review we will provide an update on the clinicopathologic manifestations, immunohistochemical profiles, molecular features, and prognosis of entities seen in FAP, with a focus on routine recognition and appropriate workup of extraintestinal manifestations.

Novel Campylobacter concisus lipooligosaccharide is a determinant of inflammatory potential and virulence

The pathogenicity of Campylobacter concisus, increasingly found in the human gastrointestinal (GI) tract, is unclear. Some studies indicate that its role in GI conditions has been underestimated, whereas others suggest that the organism has a commensal-like phenotype. For the enteropathogen C. jejuni, the lipooligosaccharide (LOS) is a main driver of virulence. We investigated the LOS structure of four C. concisus clinical isolates and correlated the inflammatory potential of each isolate with bacterial virulence. Mass spectrometric analyses of lipid A revealed a novel hexa-acylated diglucosamine moiety with two or three phosphoryl substituents. Molecular and fragment ion analysis indicated that the oligosaccharide portion of the LOS had only a single phosphate and lacked phosphoethanolamine and sialic acid substitution, which are hallmarks of the C. jejuni LOS. Consistent with our structural findings, C. concisus LOS and live bacteria induced less TNF-α secretion in human monocytes than did C. jejuni Furthermore, the C. concisus bacteria were less virulent than C. jejuni in a Galleria mellonella infection model. The correlation of the novel lipid A structure, decreased phosphorylation, and lack of sialylation along with reduced inflammatory potential and virulence support the significance of the LOS as a determinant in the relative pathogenicity of C. concisus.

Innate immune response to lipooligosaccharide: pivotal regulator of the pathobiology of invasive Neisseria meningitidis infections

Infections due to Neisseria meningitidis afflict more than one million people worldwide annually and cause death or disability in many survivors. The clinical course of invasive infections has been well studied, but our understanding of the cause of differences in patient outcomes has been limited because these are dependent on multiple factors including the response of the host, characteristics of the bacteria and interactions between the host and the bacteria. The meningococcus is a highly inflammatory organism, and the lipooligosaccharide (LOS) on the outer membrane is the most potent inflammatory molecule it expresses due to the interactions of the lipid A moiety of LOS with receptors of the innate immune system. We previously reported that increased phosphorylation of hexaacylated neisserial lipid A is correlated with greater inflammatory potential. Here we postulate that variability in lipid A phosphorylation can tip the balance of innate immune responses towards homeostatic tolerance or proinflammatory signaling that affects adaptive immune responses, causing disease with meningitis only, or septicemia with or without meningitis, respectively. Furthermore, we propose that studies of the relationship between bacterial virulence and gene expression should consider whether genetic variation could affect properties of biosynthetic enzymes resulting in LOS structural differences that alter disease pathobiology.

Gastric heterotopia in rectum: A literature review and its diagnostic pitfall

Objectives:

The term heterotopia, in pathology, refers to the presence of normal tissues at foreign sites. Gastric heterotopia has been reported anywhere in the gastrointestinal tract. However, the presence of gastric heterotopia in the rectum is very rare.

Methods:

We, here, report a rare case of a localized 2-cm area of cratered mucosa with heaped-up borders in the rectum of a 51-year-old, asymptomatic woman who underwent screening colonoscopy.

Results:

Histologic examination of the biopsy from the lesional tissue in rectum demonstrated fragments of rectal mucosa co-mingling with oxyntic- and antral-type gastric mucosa. No intestinal metaplasia or Helicobacter pylori is identified.

Conclusion:

Patients with gastric heterotopia in rectum usually present with bleeding and/or abdominal pain. Definite treatment of choice is surgical or endoscopic resection, although the lesions also respond to histamine-2 receptor blockers. In this article, most recent literature about gastric heterotopia in rectum is reviewed, following a case presentation about it.

Analysis of Bacterial Lipooligosaccharides by MALDI-TOF MS with Traveling Wave Ion Mobility

Lipooligosaccharides (LOS) are major microbial virulence factors displayed on the outer membrane of rough-type Gram-negative bacteria. These amphipathic glycolipids are comprised of two domains, a core oligosaccharide linked to a lipid A moiety. Isolated LOS samples are generally heterogeneous mixtures of glycoforms, with structural variability in both domains. Traditionally, the oligosaccharide and lipid A components of LOS have been analyzed separately following mild acid hydrolysis, although important acid-labile moieties can be cleaved. Recently, an improved method was introduced for analysis of intact LOS by MALDI-TOF MS using a thin layer matrix composed of 2,4,6-trihydroxyacetophenone (THAP) and nitrocellulose. In addition to molecular ions, the spectra show in-source "prompt" fragments arising from regiospecific cleavage between the lipid A and oligosaccharide domains. Here, we demonstrate the use of traveling wave ion mobility spectrometry (TWIMS) for IMS-MS and IMS-MS/MS analyses of intact LOS from Neisseria spp. ionized by MALDI. Using IMS, the singly charged prompt fragments for the oligosaccharide and lipid A domains of LOS were readily separated into resolved ion plumes, permitting the extraction of specific subspectra, which led to increased confidence in assigning compositions and improved detection of less abundant ions. Moreover, IMS separation of precursor ions prior to collision-induced dissociation (CID) generated time-aligned, clean MS/MS spectra devoid of fragments from interfering species. Incorporating IMS into the profiling of intact LOS by MALDI-TOF MS exploits the unique domain structure of the molecule and offers a new means of extracting more detailed information from the analysis. Graphical Abstract ᅟ.

Lipooligosaccharide Structures of Invasive and Carrier Isolates of Neisseria meningitidis Are Correlated with Pathogenicity and Carriage

The degree of phosphorylation and phosphoethanolaminylation of lipid A on neisserial lipooligosaccharide (LOS), a major cell-surface antigen, can be correlated with inflammatory potential and the ability to induce immune tolerance in vitro. On the oligosaccharide of the LOS, the presence of phosphoethanolamine and sialic acid substituents can be correlated with in vitro serum resistance. In this study, we analyzed the structure of the LOS from 40 invasive isolates and 25 isolates from carriers of Neisseria meningitidis without disease. Invasive strains were classified as groups 1-3 that caused meningitis, septicemia without meningitis, and septicemia with meningitis, respectively. Intact LOS was analyzed by high resolution matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Prominent peaks for lipid A fragment ions with three phosphates and one phosphoethanolamine were detected in all LOS analyzed. LOS from groups 2 and 3 had less abundant ions for highly phosphorylated lipid A forms and induced less TNF-α in THP-1 monocytic cells compared with LOS from group 1. Lipid A from all invasive strains was hexaacylated, whereas lipid A of 6/25 carrier strains was pentaacylated. There were fewer O-acetyl groups and more phosphoethanolamine and sialic acid substitutions on the oligosaccharide from invasive compared with carrier isolates. Bioinformatic and genomic analysis of LOS biosynthetic genes indicated significant skewing to specific alleles, dependent on the disease outcome. Our results suggest that variable LOS structures have multifaceted effects on homeostatic innate immune responses that have critical impact on the pathophysiology of meningococcal infections.

Comparative analyses of proteins from Haemophilus influenzae biofilm and planktonic populations using metabolic labeling and mass spectrometry

Background

Non-typeable H. influenzae (NTHi) is a nasopharyngeal commensal that can become an opportunistic pathogen causing infections such as otitis media, pneumonia, and bronchitis. NTHi is known to form biofilms. Resistance of bacterial biofilms to clearance by host defense mechanisms and antibiotic treatments is well-established. In the current study, we used stable isotope labeling by amino acids in cell culture (SILAC) to compare the proteomic profiles of NTHi biofilm and planktonic organisms. Duplicate continuous-flow growth chambers containing defined media with either “light” (L) isoleucine or “heavy” (H) ¹³C₆-labeled isoleucine were used to grow planktonic (L) and biofilm (H) samples, respectively. Bacteria were removed from the chambers, mixed based on weight, and protein extracts were generated. Liquid chromatography-mass spectrometry (LC-MS) was performed on the tryptic peptides and 814 unique proteins were identified with 99% confidence.

Results

Comparisons of the NTHi biofilm to planktonic samples demonstrated that 127 proteins showed differential expression with p-values ≤0.05. Pathway analysis demonstrated that proteins involved in energy metabolism, protein synthesis, and purine, pyrimidine, nucleoside, and nucleotide processes showed a general trend of downregulation in the biofilm compared to planktonic organisms. Conversely, proteins involved in transcription, DNA metabolism, and fatty acid and phospholipid metabolism showed a general trend of upregulation under biofilm conditions. Selected reaction monitoring (SRM)-MS was used to validate a subset of these proteins; among these were aerobic respiration control protein ArcA, NAD nucleotidase and heme-binding protein A.

Conclusions

The present proteomic study indicates that the NTHi biofilm exists in a semi-dormant state with decreased energy metabolism and protein synthesis yet is still capable of managing oxidative stress and in acquiring necessary cofactors important for biofilm survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-014-0329-9) contains supplementary material, which is available to authorized users.

Interrelationships of nutrition, metabolic hormones and resumption of ovulation in multiparous suckled beef cows on subtropical pastures

The effect of nutrition before and after calving on metabolic status and the resumption of ovulation postpartum was examined in multiparous sucked beef cows on subtropical pastures. At 6-7 months of gestation, Droughtmaster cows were randomly assigned on body weight (BW) and stage of gestation to two groups that received either standard subtropical pasture (SP, n = 7, 543 ± 12 kg BW) or improved pasture (IP, n = 7, 564 ± 12 kg BW). The two nutritional treatments were maintained after calving. Starting at 1 week after calving, cows were monitored for BW and body condition score (BCS, biweekly) and for circulating concentrations of insulin, glucose, IGF-1, GH and leptin (weekly). Ovarian follicular status was monitored weekly by trans-rectal ultrasonography. Fecal samples were obtained at 3-week intervals to ascertain percentage crude protein (%CP) and dry matter digestibility (DMD) of pastures. Crude protein and DMD were greater (P < 0.05) for cows on IP during the first 9 weeks after calving after which there were no differences between nutritional treatments. Cows on IP were heavier (P < 0.05) and had a greater (P < 0.01) BCS than cows on SP at 1 week after calving (585 ± 9 kg and 3.7 ± 0.2 BCS and 528 ± 21 kg and 2.3 ± 0.2 BCS, respectively). Cows on SP showed a gradual increase in BW and there were no differences in BW after approximately 7 weeks postpartum whilst BCS remained less for cows on SP. Plasma concentrations of insulin, glucose, IGF-1 and leptin were all greater (P < 0.01) for cows on IP compared with cows on SP, whilst GH did not differ. The diameter of the largest follicle did not differ between cows on IP and SP throughout the postpartum period. However, 7 of 7 cows on IP resumed ovulations between 12 and 15 weeks postpartum whilst only 1 of 7 cows on SP had resumed ovulation during the study. It is concluded from the findings that exposure of cows to IP and SP before and after calving resulted in two groups of cows with different metabolic homeostasis and that the greater circulating concentrations of insulin, glucose, IGF-1 and leptin promoted the earlier resumption of ovulation for cows on IP.

Lack of lipid A pyrophosphorylation and functional lptA reduces inflammation by Neisseria commensals

The interaction of the immune system with Neisseria commensals remains poorly understood. We have previously shown that phosphoethanolamine on the lipid A portion of lipooligosaccharide (LOS) plays an important role in Toll-like receptor 4 (TLR4) signaling. For pathogenic Neisseria, phosphoethanolamine is added to lipid A by the phosphoethanolamine transferase specific for lipid A, which is encoded by lptA. Here, we report that Southern hybridizations and bioinformatics analyses of genomic sequences from all eight commensal Neisseria species confirmed that lptA was absent in 15 of 17 strains examined but was present in N. lactamica. Mass spectrometry of lipid A and intact LOS revealed the lack of both pyrophosphorylation and phosphoethanolaminylation in lipid A of commensal species lacking lptA. Inflammatory signaling in human THP-1 monocytic cells was much greater with pathogenic than with commensal Neisseria strains that lacked lptA, and greater sensitivity to polymyxin B was consistent with the absence of phosphoethanolamine. Unlike the other commensals, whole bacteria of two N. lactamica commensal strains had low inflammatory potential, whereas their lipid A had high-level pyrophosphorylation and phosphoethanolaminylation and induced high-level inflammatory signaling, supporting previous studies indicating that this species uses mechanisms other than altering lipid A to support commensalism. A meningococcal lptA deletion mutant had reduced inflammatory potential, further illustrating the importance of lipid A pyrophosphorylation and phosphoethanolaminylation in the bioactivity of LOS. Overall, our results indicate that lack of pyrophosphorylation and phosphoethanolaminylation of lipid A contributes to the immune privilege of most commensal Neisseria strains by reducing the inflammatory potential of LOS.

Proteomic analysis of Neisseria gonorrhoeae biofilms shows shift to anaerobic respiration and changes in nutrient transport and outermembrane proteins

Neisseria gonorrhoeae, the causative agent of gonorrhea, can form biofilms in vitro and in vivo. In biofilms, the organism is more resistant to antibiotic treatment and can serve as a reservoir for chronic infection. We have used stable isotope labeling by amino acids in cell culture (SILAC) to compare protein expression in biofilm and planktonic organisms. Two parallel populations of N. gonorrhoeae strain 1291, which is an arginine auxotroph, were grown for 48 h in continuous-flow chambers over glass, one supplemented with (13)C(6)-arginine for planktonic organisms and the other with unlabeled arginine for biofilm growth. The biofilm and planktonic cells were harvested and lysed separately, and fractionated into three sequential protein extracts. Corresponding heavy (H) planktonic and light (L) biofilm protein extracts were mixed and separated by 1D SDS-PAGE gels, and samples were extensively analyzed by liquid chromatography-mass spectrometry. Overall, 757 proteins were identified, and 152 unique proteins met a 1.5-fold cutoff threshold for differential expression with p-values <0.05. Comparing biofilm to planktonic organisms, this set included 73 upregulated and 54 downregulated proteins. Nearly a third of the upregulated proteins were involved in energy metabolism, with cell envelope proteins making up the next largest group. Of the downregulated proteins, the largest groups were involved in protein synthesis and energy metabolism. These proteomics results were compared with our previously reported results from transcriptional profiling of gonococcal biofilms using microarrays. Nitrite reductase and cytochrome c peroxidase, key enzymes required for anaerobic growth, were detected as highly upregulated in both the proteomic and transcriptomic datasets. These and other protein expression changes observed in the present study were consistent with a shift to anaerobic respiration in gonococcal biofilms, although changes in membrane proteins not explicitly related to this shift may have other functions.

Animal-level factors affecting ovarian function in Bos indicus heifers treated to synchronize ovulation with intravaginal progesterone-releasing devices and oestradiol benzoate

The primary objective of this study was to investigate the impact of animal-level factors including energy balance and environmental/management stress, on the ovarian function of Bos indicus heifers treated to synchronize ovulation. Two-year-old Brahman (BN) (n = 30) and BN-cross (n = 34) heifers were randomly allocated to three intravaginal progesterone-releasing device (IPRD) treatment groups: (i) standard-dose IPRD [Cue-Mate(®) (CM) 1.56 g; n = 17]; (ii) half-dose IPRD [0.78 g progesterone (P(4)); CM 0.78 g; n = 15]; (iii) half-dose IPRD + 300 IU equine chorionic gonadotrophin at IPRD removal (CM 0.78 g + G; n = 14); (iv) and a control group, 2× PGF(2α) [500 μg prostaglandin F(2α) (PGF(2α))] on Day -16 and -2 (n = 18). Intravaginal progesterone-releasing device-treated heifers received 250 μg PGF(2α) at IPRD insertion (Day -10) and IPRD removal (Day -2) and 1 mg oestradiol benzoate on Day -10 and -1. Heifers were managed in a small feedlot and fed a defined ration. Ovarian function was evaluated by ultrasonography and plasma P(4) throughout the synchronized and return cycles. Energy balance was evaluated using plasma insulin-like growth factor 1 (IGF-I) and glucose concentrations. The impact of environmental stressors was evaluated using plasma cortisol concentration. Heifers that had normal ovarian function had significantly higher IGF-I concentrations at commencement of the experiment (p = 0.008) and significantly higher plasma glucose concentrations at Day -2 (p = 0.040) and Day 4 (p = 0.043), than heifers with abnormal ovarian function. There was no difference between the mean pre-ovulatory cortisol concentrations of heifers that ovulated or did not ovulate. However, heifers that ovulated had higher cortisol concentrations at Day 4 (p = 0.056) and 6 (p = 0.026) after ovulation than heifers that did not ovulate.

miRNA-29b suppresses prostate cancer metastasis by regulating epithelial-mesenchymal transition signaling

Prostate cancer remains the second leading cause of cancer deaths among American men. Early diagnosis increases survival rate in patients; however, treatments for advanced disease are limited to hormone ablation techniques and palliative care. Thus, new methods of treatment are necessary for inhibiting prostate cancer disease progression. Here, we have shown that miRNA-29b (miR-29b) expression was lower in prostate cancer cells (PC3 and LNCaP) as compared with immortalized prostate epithelial cells. Between these two prostate cancer cell lines, metastatic prostate cancer PC3 cells displayed lower expression of miR-29b. We also observed a significant downregulation of miR-29b expression in human prostate cancer tissues as compared with patient-matched nontumor tissues. PC3 cells ectopically expressing miR-29b inhibited wound healing, invasiveness, and failed to colonize in the lungs and liver of severe combined immunodeficient mice after intravenous injection, while PC3 cells expressing a control miRNA displayed metastasis. Epithelial cell marker E-cadherin expression was enhanced miR-29b transfected in prostate cancer cells as compared with cells expressing control miRNA. On the other hand, N-cadherin, Twist, and Snail expression was downregulated in PC3 cells expressing miR-29b. Together these results suggested that miR-29b acts as an antimetastatic miRNA for prostate cancer cells at multiple steps in a metastatic cascade. Therefore, miR-29b could be a potentially new attractive target for therapeutic intervention in prostate cancer.

The lipid A from Vibrio fischeri lipopolysaccharide: a unique structure bearing a phosphoglycerol moiety

Vibrio fischeri, a bioluminescent marine bacterium, exists in an exclusive symbiotic relationship with the Hawaiian bobtail squid, Euprymna scolopes, whose light organ it colonizes. Previously, it has been shown that the lipopolysaccharide (LPS) or free lipid A of V. fischeri can trigger morphological changes in the juvenile squid's light organ that occur upon colonization. To investigate the structural features that might be responsible for this phenomenon, the lipid A from V. fischeri ES114 LPS was isolated and characterized by multistage mass spectrometry (MS(n)). A microheterogeneous mixture of mono- and diphosphorylated diglucosamine disaccharides was observed with variable states of acylation ranging from tetra- to octaacylated forms. All lipid A species, however, contained a set of conserved primary acyl chains consisting of an N-linked C14:0(3-OH) at the 2-position, an unusual N-linked C14:1(3-OH) at the 2'-position, and two O-linked C12:0(3-OH) fatty acids at the 3- and 3'-positions. The fatty acids found in secondary acylation were considerably more variable, with either a C12:0 or C16:1 at the 2-position, C14:0 or C14:0(3-OH) at the 2'-position, and C12:0 or no substituent at the 3'-position. Most surprising was the presence of an unusual set of modifications at the secondary acylation site of the 3-position consisting of phosphoglycerol (GroP), lysophosphatidic acid (GroP bearing C12:0, C16:0, or C16:1), or phosphatidic acid (GroP bearing either C16:0 + C12:0 or C16:0 + C16:1). Given their unusual nature, it is possible that these features of the V. fischeri lipid A may underlie the ability of E. scolopes to recognize its symbiotic partner.

Immunosuppression enhances oncolytic adenovirus replication and antitumor efficacy in the Syrian hamster model

We recently described an immunocompetent Syrian hamster model for oncolytic adenoviruses (Ads) that permits virus replication in tumor cells as well as some normal tissues. This model allows exploration of interactions between the virus, tumor, normal organs, and host immune system that could not be examined in the immunodeficient or nonpermissive animal models previously used in the oncolytic Ad field. Here we asked whether the immune response to oncolytic Ad enhances or limits antitumor efficacy. We first determined that cyclophosphamide (CP) is a potent immunosuppressive agent in the Syrian hamster and that CP alone had no effect on tumor growth. Importantly, we found that the antitumor efficacy of oncolytic Ads was significantly enhanced in immunosuppressed animals. In animals that received virus therapy plus immunosuppression, significant differences were observed in tumor histology, and in many cases little viable tumor remained. Notably, we also determined that immunosuppression allowed intratumoral virus levels to remain elevated for prolonged periods. Although favorable tumor responses can be achieved in immunocompetent animals, the rate of virus clearance from the tumor may lead to varied antitumor efficacy. Immunosuppression, therefore, allows sustained Ad replication and oncolysis, which leads to substantially improved suppression of tumor growth.

Fine needle aspiration biopsy of splenic hamartoma with bizarre stromal cells: a case report

BACKGROUND

Splenic hamartoma is a rare benign "tumor" with disorganized red pulp tissue without white pulp elements. Recently described cases show bizarre stromal cells. Splenic hamartoma has only rarely been described cytologically; the bizarre stromal variant has not been reported.

CASE

A 64-year-old woman with history of low-grade malignant fibrous histiocytoma had an isolated, solitary lesion with fluorodeoxyglucose avidity in the spleen on positron emission tomography imaging, and computed tomography-guided fine needle aspiration biopsy was performed. Smears were cellular with large cohesive fragments of spindled to ovoid cells with intermixed bizarre large cells present singly in the background and within groups. Cell fragments possessed a variable proportion of spindle to ovoid cells. The bizarre large cells had single or multiple round, oval or distorted nuclei with granular chromatin. Cell block mirrored the smear pattern, and the bizarre large cells were negative by immunohistochemistry. Malignant spindle cell neoplasm was favored. After splenectomy, splenic hamartoma with bizarre stromal cells was diagnosed.

CONCLUSION

Splenic hamartoma with bizarre stromal cells is a challenging diagnosis cytologically. In the spleen, it should be considered in the differential diagnosis of entities with bizarre large cells in a background of spindled elements.

Secondary Amyloidosis in the Hydrops Lesion of a Patient With Pellucid Marginal Degeneration

PURPOSE

To report a case of secondary corneal amyloidosis in a chronic hydrops lesion of a patient with pellucid marginal degeneration (PMD).

METHODS

Clinicopathologic case report with a review of the literature. A 63-year-old man with PMD developed acute hydrops in 1999, which never resolved and became an elevated, gelatinous lesion with peripheral neovascularization. Penetrating keratoplasty was performed in 2005, and the excised button was examined histopathologically.

RESULTS

The excised button revealed substantial subepithelial acellular deposits consistent with amyloid in the area of the unresolved gelatinous lesion, overlying a disruption in Descemet membrane, confirming the diagnosis of secondary corneal amyloidosis.

CONCLUSIONS

Secondary corneal amyloidosis is a corneal response to chronic injury and irritation that is not commonly reported and often overlooked. To the best of our knowledge, this is the first report of a dramatic secondary amyloidosis deposit in the chronic hydrops lesion of a patient with PMD.

Characterization of lipid A acylation patterns in Francisella tularensis, Francisella novicida, and Francisella philomiragia using multiple-stage mass spectrometry and matrix-assisted laser desorption/ionization on an intermediate vacuum source linear ion trap

Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria. The lipid A region of LPS stimulates the immune system in a structure-dependent manner. We have previously identified the two major lipid A species from Francisella tularensis as asymmetric tetraacylated structures containing four long acyl chains (16 and 18 carbons) and a single phosphate group that is partially modified by galactosamine (Phillips, N. J.; Schilling B.; McLendon, M. K.; Apicella, M. A.; Gibson, B. W. Infect. Immun. 2004, 72, 5340-5348). In the current study, we used matrix-assisted laser desorption/ionization on an intermediate vacuum source (vMALDI) coupled to a linear ion trap (LIT) mass spectrometer in multiple-stage mass fragmentation mode (MSn) to determine the structures of several minor and low abundant lipid A species present in F. tularensis, Francisella novicida, and Francisella philomiragia LPS that have not been previously characterized. Comprehensive vMALDI-MSn fragmentation studies allowed us to deduce the composition and the position of the fatty acid substituents within the lipid A moieties. Unexpectedly, most of these minor lipid A species consisted of multiple isobaric species with acyl chains of various lengths. Moreover, we found that a small portion of these lipid A species may be modified by the addition of a hexose or hexosamine sugar, in addition to the galactosamine that was previously identified. Overall, we found that MSn analysis on the vMALDI-LIT-MS platform was highly efficient and sensitive, allowing for thorough analysis of very minor lipid A species.

Cat scratch disease causing hepatic masses after liver transplant

Hepatic cat scratch disease is rarely reported in liver transplant recipients and has never been reported with discrete liver lesions in the graft. A 52-year-old woman was transplanted for hepatitis C cirrhosis and hepatocellular carcinoma. Her posttransplant course was uneventful. She presented 2.7 years after transplantation with fever of unknown origin and went on to develop multiple and diffuse discrete liver lesions. Despite an extensive work-up including percutaneous and laparoscopic biopsies, a subsegmental resection that included one of these masses was required to make the diagnosis of Bartonella henselae infection. Serologic tests were equivocal. Histology was consistent with cat scratch disease of the liver, and polymerase chain reaction (PCR) testing of the resected tissue confirmed the diagnosis. Response to doxycycline was rapid. Fevers resolved within 7 days. Repeat abdominal CT scan showed reduction of the liver masses. Cat scratch disease should be considered in postliver transplant patients presenting with fever and liver lesions, especially if close contact with cats has occurred. Diagnosis by PCR testing of involved tissue is preferred when serologies are equivocal due to immunosuppression.

The treatment of early stage cervical cancer: an assessment of pre-operative factors

OBJECTIVE

To assess the pre-operative clinical factors of a group of early stage cervical cancer patients and correlate them to the risk for adjuvant radiotherapy using GOG 92 and 109 criteria.

METHOD

A retrospective chart review of cervical cancer patients treated at the Saint Louis University Division of Gynecologic Oncology between the years 1989 and 2004 was performed. The results were compared with chi-squared testing and multivariable regression analysis. A p-value of 0.05 was considered significant.

RESULTS

One hundred and thirty-one cervical cancer patients underwent exploration for radical hysterectomy during the study time period. Five patients had stage IA1 disease, 6 patients had stage IA2 disease, 98 patients had stage IB1 disease, 20 patients had stage IB2 disease and one patient had stage IIA disease. No patient with stage IA1 or IA2 disease met criteria for adjuvant radiotherapy. The patients with stage IB1 tumors who were 45 years of age or younger and had tumors up to 2 cm in diameter had a low (14%) likelihood for treatment with adjuvant radiotherapy. The patients with stage IB1 tumors who were older than 45 years of age with tumors larger than 2 cm in diameter and the patients with stage IB2 tumors both had a high likelihood for adjuvant radiotherapy (77% and 90% respectively).

CONCLUSION

In our study group, the stage of cervical cancer and a combination of tumor diameter and patient age was found to stratify early stage cervical cancer patients by likelihood for adjuvant radiotherapy.

Novel modification of lipid A of Francisella tularensis

We have investigated the lipid A of Francisella tularensis subsp. holarctica strain 1547-57, a type B strain, by using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, nanoelectrospray quadrupole ion-trap mass spectrometry, and chemical methods. In accordance with the previously published structures of the lipid A from F. tularensis live vaccine strain (LVS) (ATCC 29684) (E. Vinogradov et al., Eur. J. Biochem. 269:6112-6118, 2002), all of the major lipid A forms from strain 1547-57 were tetraacylated. As in the LVS strain, the major fatty acids detected in the F. tularensis 1547-57 lipid A sample included 3-hydroxyoctadecanoic acid, 3-hydroxyhexadecanoic acid, hexadecanoic acid, and tetradecanoic acid. However, several of the lipid A components present in strain 1547-57 were of higher molecular weight than the previously published structures. A major component with an M(r) of 1,666 was found to contain three C(18:0)(3-OH) fatty acids, one C(16:0) fatty acid, one phosphate group, and one 161-Da moiety. This 161-Da moiety could be removed from the lipid A by treatment with aqueous hydrofluoric acid and was identified as galactosamine following peracetylation and analysis by gas chromatography-mass spectrometry. Detailed investigations of the M(r)-1,666 species by ion-trap mass spectrometry with multiple stages of fragmentation suggested that the galactosamine-1-phosphate was linked to the reducing terminus of the lipid A. Similar to the modification of lipid A with arabinosamine, lipopolysaccharide species from F. tularensis containing a phosphate-linked galactosamine could potentially influence its intracellular survival by conferring resistance to antimicrobial peptides.

Nontypeable Haemophilus influenzae strain 2019 produces a biofilm containing N-acetylneuraminic acid that may mimic sialylated O-linked glycans

Previous studies suggested that nontypeable Haemophilus influenzae (NTHI) can form biofilms during human and chinchilla middle ear infections. Microscopic analysis of a 5-day biofilm of NTHI strain 2019 grown in a continuous-flow chamber revealed that the biofilm had a diffuse matrix interlaced with multiple water channels. Our studies showed that biofilm production was significantly decreased when a chemically defined medium lacking N-acetylneuraminic acid (sialic acid) was used. Based on these observations, we examined mutations in seven NTHI strain 2019 genes involved in carbohydrate and lipooligosaccharide biosynthesis. NTHI strain 2019 with mutations in the genes encoding CMP-N-acetylneuraminic acid synthetase (siaB), one of the three NTHI sialyltransferases (siaA), and the undecaprenyl-phosphate alpha-N-acetylglucosaminyltransferase homolog (wecA) produced significantly smaller amounts of biofilm. NTHI strain 2019 with mutations in genes encoding phosphoglucomutase (pgm), UDP-galactose-4-epimerase, and two other NTHI sialyltransferases (lic3A and lsgB) produced biofilms that were equivalent to or larger than the biofilms produced by the parent strain. The biofilm formed by the NTHI strain 2019pgm mutant was studied with Maackia amurensis fluorescein isothiocyanate (FITC)-conjugated and Sambucus nigra tetramethyl rhodamine isocyanate (TRITC)-conjugated lectins. S. nigra TRITC-conjugated lectin bound to this biofilm, while M. amurensis FITC-conjugated lectin did not. S. nigra TRITC-conjugated lectin binding was inhibited by incubation with alpha2,6-neuraminyllactose and by pretreatment of the biofilm with Vibrio cholerae neuraminidase. Matrix-assisted laser desorption ionization-time of flight mass spectometry analysis of lipooligosaccharides isolated from a biofilm, the planktonic phase, and plate-grown organisms showed that the levels of most sialylated glycoforms were two- to fourfold greater when the lipooligosaccharide was derived from planktonic or biofilm organisms. Our data indicate that NTHI strain 2019 produces a biofilm containing alpha2,6-linked sialic acid and that the sialic acid content of the lipooligosaccharides increases concomitant with the transition of organisms to a biofilm form.

Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry of lipopolysaccharide species separated by slab-polyacrylamide gel electrophoresis: High-resolution separation and molecular weight determination of lipooligosaccharides fromVibrio fischeri strain HMK

We recently demonstrated that the combined use of lipopolysaccharide (LPS) reverse staining and high-efficiency passive elution techniques can be successfully used as a suitable interface between LPS slab-gel separation and electrospray ionization-mass spectrometry (ESI-MS) of LPS-derived oligosaccharides. Here, we extend our micropurification strategy for the analysis of O-deacylated LPS forms from Vibrio fischeri HMK after recovery from single reverse-stained LPS bands using matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). The quantities (30-40 microg) obtained from the two gel-resolved LPS bands were sufficient to allow MALDI-TOF-MS detection of O-deacylated LPS glycoforms at m/z 3767.1, 3890.1 for the high-molecular-weight or at m/z 2522.5, 2645.4, 2725.7, and 2848.7 for the low-molecular-weight LPS band. These LPS band heterogeneities resulted not only from variations in the oligosaccharide region of the LPS but also from two phosphorylation states of the lipid A (diphosphoryl and diphosphoryl plus a single phosphoethanolamine substitution). On the other hand, MALDI-TOF mass spectra of the separated LPS bands displayed reduced heterogeneity and increased signal-to-noise ratios as compared to spectra of the unpurified LPS. Furthermore, micropurification of LPS bands prior MALDI-TOF-MS led to a higher sensitivity of detection of less abundant low-molecular-weight LPS glycoforms. Taken together, this and our previous study on gel-micropurified LPS using ESI definitively show how one can unambiguously determine the different molecular species contained within each gel-separated LPS band, their relative abundance and oligosaccharide sequences.

Relationship between thirty post-thaw spermatozoal characteristics and the field fertility of 11 high-use Australian dairy AI sires

This study determined the relationship between two measures of field fertility of 11 high-use Australian artificial insemination (AI) dairy bulls and thirty standard laboratory assessments of spermatozoal post-thaw viability. The two measures of field fertility used, conception rates (cCR) and non-return rates (cNRR), were both corrected for all major non-bull variables. Sperm viability assessments were conducted on semen collected within the same season as that used to derive the field fertility estimates. These assessments measured sperm concentration, motility, morphology and membrane integrity at thawing, after 2h incubation and after the swim-up sperm selection procedure. Derivations of these measures and in vitro embryo fertilizing and developmental capacity were also determined. The Genstat Statistical Package [Genstat 5 Release 4.2 Reference Manual, VSN International, Oxford, 2000] was used to conduct an analysis of variance on the viability parameters across semen straws and bulls, and to calculate the strength of correlation between each semen parameter, cNRR and cCR in a correlation matrix. Step forward multiple regression identified the combination of semen parameters that were most highly correlated with cCR and with cNRR. The sperm parameters identified as being most predictive of cCR were the percentage of morphologically normal sperm immediately post-thaw (zeroNorm), the number of morphologically normal sperm after the swim-up procedure (nSuNorm), and the rate of zygote cleavage in vitro (Clv); the predictive equation formed by these parameters accounted for 70% of variance. The predictive equation produced for cNRR contained the variables zeroNorm, the proportion of membrane intact sperm after 2h incubation at 37 degrees C (twoMem) and Clv and accounted for 76.5% of the variation. ZeroNorm was found to be consistent across straws and semen batches within-bull and the sperm parameter with the strongest individual predictive capacity for both cCR (P=0.1) and cNRR (P=0.001). Post-thaw sperm parameters can be used to predict field fertility of Australian dairy sires; the calculated predictive equations are particularly useful for identifying and monitoring bulls of very high and very low potential fertility within a group.

Expression of hepatitis C virus non-structural 5A protein in the liver of transgenic mice

Hepatitis C virus (HCV) is a major etiologic agent for chronic hepatitis worldwide often leading to the development of cirrhosis and hepatocellular carcinoma. However, the mechanism for development of chronic hepatitis or hepatocarcinogenesis by HCV remains unclear. HCV NS5A protein possesses many intriguing properties, including sequestration of p53 in the cytoplasm, downregulation of p21 protein, activation of STAT3, and inhibition of tumor necrosis factor-alpha-mediated apoptosis. Thus, we investigated whether this viral protein has oncogenic property in vivo. In the absence of an efficient cell culture system for virus growth and a suitable small animal model for HCV infection, transgenic FVB mice were generated by targeting the HCV NS5A genomic region cloned under the control of a liver-specific apoE promoter or mouse major urinary promoter (MUP). The apoE promoter is constitutively expressed in liver, on the other hand, the MUP is developmentally regulated and expressed in the liver after birth. Reverse transcription polymerase chain reaction and Western blot analysis indicated establishment of HCV NS5A transgene expression in several lines from both groups of mice. Immunohistochemical studies suggested the presence of NS5A in the cytoplasm of hepatocytes. The transgenic animals were phenotypically similar to their normal littermates and did not exhibit a major histological change within the liver up to 24 months of age. Our results suggested HCV NS5A protein is not directly cytopathic or oncogenic in this FVB transgenic mouse model, although this viral protein promotes cell growth in vitro. These animals will be a valuable model of HCV immunopathology as well as for evaluation of siRNA, interferon and other cytokine therapies.

Treatment of primary degenerative arthritis of the elbow by ulnohumeral arthroplasty. A long-term follow-up

Between 1990 and 1996 we performed 20 consecutive ulnohumeral arthroplasties for primary osteoarthritis of the elbow. The outcome was assessed using the Disabilities of Arm, Shoulder and Hand Score (DASH) and the Mayo Elbow Performance Score (MEPS) at a mean follow-up of 75 months (58 to 132). There were excellent or good results in 17 elbows (85%) using the DASH score and in 13 (65%) with the MEPS (correlation coefficient 0.79). The mean fixed flexion deformity had improved by 10 degrees and the range of flexion by a mean of 20 degrees. In 16 elbows (80%) the benefits of surgery had been maintained, and of 16 patients working at the time of operation, 12 (75%) had returned to the same job. There was no correlation between radiological recurrence of degenerative changes and the amount of fixed flexion deformity, the flexion arc, or the elbow scores.

The msbB mutant of Neisseria meningitidis strain NMB has a defect in lipooligosaccharide assembly and transport to the outer membrane

A deletion-insertion mutation in msbB, a gene that encodes a lipid A acyltransferase, was introduced into encapsulated Neisseria meningitidis serogroup B strain NMB and an acapsular mutant of the same strain. These mutants were designated NMBA11K3 and NMBA11K3cap-, respectively. Neither lipooligosaccharide (LOS) nor lipid A could be isolated from NMBA11K3 although a number of techniques were tried, but both were easily extracted from NMBA11K3cap-. Immunoelectron microscopy using monoclonal antibody (MAb) 6B4, which recognizes the terminal Galbeta1-4GlcNAc of LOS, demonstrated that NMB, NMBcap-, and NMBA11K3cap- expressed LOS circumferentially, while MAb 6B4 did not bind to the surface of NMBA11K3. However, cytoplasmic staining of NMBA11K3 with MAb 6B4 was a consistent observation. Mass-spectrometric analyses demonstrated that the relative amounts of the lipid A-specific C12:0 3-OH and C14:0 3-OH present in the membrane preparations (MP) from NMBA11K3 were substantially decreased (25- and 23-fold, respectively) compared to the amount in MP from its parent strain, NMB. Western blot analyses of MP from NMBA11K3 demonstrated that the levels of porin in the outer membrane of NMBA11K3 were also substantially decreased. These studies suggest that the lipid A acylation defect in encapsulated NMBA11K3 influences the assembly of the lipid A and consequently the incorporation of porin in the outer membrane.

Malignant fibrous histiocytoma of the lung presenting as bronchial obstruction in a heart transplant recipient

We present a case of acute respiratory failure secondary to bronchial obstruction caused by a rare form of sarcoma, malignant fibrous histiocytoma, in a heart transplant recipient with a history of wheezing for several months. Despite attempts at palliative endoscopic argon coagulation, the patient expired soon after presentation.

The lbgAB gene cluster of Haemophilus ducreyi encodes a beta-1,4-galactosyltransferase and an alpha-1,6-DD-heptosyltransferase involved in lipooligosaccharide biosynthesis

All Haemophilus ducreyi strains examined contain a lipooligosaccharide (LOS) consisting of a single but variable branch oligosaccharide that emanates off the first heptose (Hep-I) of a conserved Hep(3)-phosphorylated 3-deoxy-D-manno-octulosonic acid-lipid A core. In a previous report, identification of tandem genes, lbgA and lbgB, that are involved in LOS biosynthesis was described (Stevens et al., Infect. Immun. 65:651-660, 1997). In a separate study, the same gene cluster was identified and the lbgB (losB) gene was found to be required for transfer of the second sugar, D-glycero-D-manno-heptose (DD-Hep), of the major branch structure (Gibson et al., J. Bacteriol. 179:5062-5071, 1997). In this study, we identified the function of the neighboring upstream gene, lbgA, and found that it is necessary for addition of the third sugar in the dominant oligosaccharide branch, a galactose-linked beta1-->4, to the DD-Hep. LOS from an lbgA mutant and an lbgAB double mutant were isolated and were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, carbohydrate analysis, mass spectrometry, and nuclear magnetic resonance spectroscopy. The results showed that the mutant strains synthesize truncated LOS glycoforms that terminate after addition of the first glucose (lbgAB) or the disaccharide DD-Hepalpha1-->6Glcbeta1 (lbgA) that is attached to the heptose core. Both mutants show a significant reduction in the ability to adhere to human keratinocytes. Although minor differences were observed after two-dimensional gel electrophoresis of total proteins from the wild-type and mutant strains, the expression levels of the vast majority of proteins were unchanged, suggesting that the differences in adherence and invasion are due to differences in LOS. These studies add to the mounting evidence for a role of full-length LOS structures in the pathophysiology of H. ducreyi infection.

Diagnosis and immediate care of injuries to the elbow and forearm

Commonly presenting to accident and emergency departments, the upper limb is often involved in trauma, either directly or as a result of a fall. Injuries associated with simple fractures may significantly affect outcomes. Accurate diagnosis of patterns of injury is vital.

Haemophilus influenzae type b strain A2 has multiple sialyltransferases involved in lipooligosaccharide sialylation

The lipooligosaccharide (LOS) of Haemophilus influenzae contains sialylated glycoforms, and a sialyltransferase, Lic3A, has been previously identified. We report evidence for two additional sialyltransferases, SiaA, and LsgB, that affect N-acetyllactosamine containing glycoforms. Mutations in genes we have designated siaA and lsgB affected only the sialylated glycoforms containing N-acetylhexosamine. A mutation in siaA resulted in the loss of glycoforms terminating in sialyl-N-acetylhexosamine and the appearance of higher molecular weight glycoforms, containing the addition of phosphoethanolamine, N-acetylgalactosamine, and N-acetylneuraminic acid. Chromosomal complementation of the siaA mutant resulted in the expression of the original sialylated LOS phenotype. A mutation in lic3A resulted in the loss of sialylation only in glycoforms lacking N-acetylhexosamine and had no effect on sialylation of the terminal N-acetyllactosamine epitope. A double mutant in siaA and lic3A resulted in the complete loss of sialylation of the terminal N-acetyllactosamine epitope and expression of the higher molecular weight sialylated glycoforms seen in the siaA mutant. Mutation of lsgB resulted in persistence of sialylated glycoforms but a reduction in N-acetyllactosamine containing glycoforms. A triple mutant of siaA, lic3A, and lsgB contained no sialylated glycoforms. These results demonstrate that the sialylation of the LOS of H. influenzae is a complex process involving multiple sialyltransferases.

Hepatitis C virus NS5A protein impairs TNF-mediated hepatic apoptosis, but not by an anti-FAS antibody, in transgenic mice

Hepatitis C virus (HCV) is a major etiologic agent of chronic hepatitis worldwide and may lead to the development of hepatocellular carcinoma. However, the mechanism of development of chronic hepatitis or hepatocarcinogenesis by HCV remains unclear. In the present study, we have investigated the effect of nonstructural protein 5A (NS5A) on TNF- and Fas-mediated apoptosis in the liver of transgenic mice. For this purpose, transgenic mice were generated by targeting the HCV NS5A genomic region cloned under the control of a liver-specific apoE promoter. The transgenic animals were phenotypically similar to their normal littermates and did not exhibit a detectable histological change in the liver at 8-12 weeks of age. Intraperitoneal injection of recombinant TNF induced hepatic injury and apoptosis in normal mice. In contrast, transgenic mice expressing NS5A protein were protected against hepatic apoptosis after injection of TNF. However, injection of anti-Fas antibody into transgenic mice did not significantly influence hepatic apoptosis compared to the normal littermates. These results suggested distinct effects of TNF and anti-Fas antibody in transgenic mice expressing NS5A. We subsequently investigated the effect of NS5A in signaling pathways involved in these two cytokine-mediated apoptosis. A physical association between NS5A and TRADD was observed by pull-down assay, coimmunoprecipitation, and colocalization experiments. Furthermore, NS5A prevented the association between TRADD and FADD and blocked TRADD-mediated NF-kappaB activation. Together, our results suggest that NS5A impairs TNF-mediated apoptosis by interfering upstream of the signal transduction pathway and may play a role in HCV-mediated pathogenesis.

Intracellular survival of Neisseria gonorrhoeae in male urethral epithelial cells: importance of a hexaacyl lipid A

Neisseria gonorrhoeae is a strict human pathogen that invades and colonizes the urogenital tracts of males and females. Lipooligosaccharide (LOS) has been shown to play a role in gonococcal pathogenesis. The acyl transferase MsbB is involved in the biosynthesis of the lipid A portion of the LOS. In order to determine the role of an intact lipid A structure on the pathogenesis of N. gonorrhoeae, the msbB gene was cloned and sequenced, a deletion and insertion mutation was introduced into N. gonorrhoeae, and the mutant strain was designated 1291A11K3. Mass spectrometric analyses of 1291A11K3 LOS determined that this mutation resulted in a pentaacyl rather than a hexaacyl lipid A structure. These analyses also demonstrated an increase in the phosphorylation of lipid A and an increase in length of the oligosaccharide of a minor species of the msbB LOS. The interactions of this mutant with male urethral epithelial cells (uec) were examined. Transmission and scanning electron microscopy studies indicated that the msbB mutants formed close associations with and were internalized by the uec at levels similar to those of the parent strain. Gentamicin survival assays performed with 1291A11K3 and 1291 bacteria demonstrated that there was no difference in the abilities of the two strains to adhere to uec; however, significantly fewer 1291A11K3 bacteria than parent strain bacteria were recovered from gentamicin-treated uec. These studies suggest that the lipid A modification in the N. gonorrhoeae msbB mutant may render it more susceptible to innate intracellular killing mechanisms when internalized by uec.

Writing long holographic diffraction gratings by use of a novel scanning method

A novel method for writing holographic diffraction gratings is proposed in which the two interfering beams are moved together across the recording medium in such a way that the interference pattern at the medium is unchanged. The phase compensation is discussed both for an idealized setup and for a realistic experimental arrangement.

Holographic optical elements recorded in silver halide sensitized gelatin emulsions. Part I. Transmission holographic optical elements

Silver halide sensitized gelatin (SHSG) holograms are similar to holograms recorded in dichromated gelatin (DCG), the main recording material for holographic optical elements (HOE's). The drawback of DCG is its low sensitivity and limited spectral response. Silver halide materials can be processed in such a way that the final hologram will have properties like a DCG hologram. Recently this technique has become more interesting since the introduction of new ultra-high-resolution silver halide emulsions. An optimized processing technique for transmission HOE's recorded in these materials is introduced. Diffraction efficiencies over 90% can be obtained for transmissive diffraction gratings. Understanding the importance of the selective hardening process has made it possible to obtain results similar to conventional DCG processing. The main advantage of the SHSG process is that high-sensitivity recording can be performed with laser wavelengths anywhere within the visible spectrum. This simplifies the manufacturing of high-quality, large-format HOE's.

Renal function, plasma homocysteine and carotid atherosclerosis in elderly people

Although epidemiological studies suggest that people with minor impairment of renal function are at higher risk of stroke and coronary heart disease, the mechanisms underlying this relation are unclear. One explanation may lie with observations that deterioration in renal function is accompanied by elevations in plasma homocysteine concentrations. There is evidence that moderate hyperhomocysteinemia may play a causal role in atherosclerotic disease. We investigated the relations between renal function, plasma homocysteine and atherosclerosis of the carotid arteries in 128 men and women aged 69-74 years. Renal function was assessed by creatinine clearance and serum creatinine. Duplex ultrasonography was used to quantify the degree of stenosis in the extracranial carotid arteries. Severity of carotid atherosclerosis was greatest in men and women with the poorest renal function, whether measured by creatinine clearance or serum creatinine. After adjustment for plasma homocysteine, pulse pressure and other cardiovascular risk factors, the odds ratio for having carotid stenosis >30% was 4.3 (95% CI 1.4-12.9) in those whose creatinine clearance rate was 55 ml/min or less compared with those whose creatinine clearance rate was >73 ml/min. Even small decrements in renal function were associated with increased risk; people whose creatinine clearance rate was between 56 and 73 ml/min had an odds ratio of 3.8 (95% CI 1.2-11.9). Plasma homocysteine concentrations were significantly higher in people with poorer renal function, but they did not explain the associations we found between carotid atherosclerosis and creatinine clearance or serum creatinine.