Genetic basis of Neisseria gonorrhoeae lipooligosaccharide antigenic variation

Neisseria gonorrhoeae lipooligosaccharide (LOS) undergoes antigenic variation at a high rate, and this variation can be monitored by changes in a strain's ability to bind LOS-specific monoclonal antibodies. We report here the cloning and identification of a gene, lsi-2, that can mediate this variation. The DNA sequence of lsi-2 has been determined for N. gonorrhoeae 1291, a strain that expresses a high-molecular-mass LOS, and a derivative of this strain, RS132L, that produces a truncated LOS. In the parental strain, lsi-2 contains a string of 12 guanines in the middle of its coding sequence. In cells that had antigenically varied to produce a truncated LOS, the number of guanines in lsi-2 was altered. Site-specific deletions were constructed to verify that expression of a 3.6-kDa LOS is due to alterations in lsi-2.

Characterization of a gyrB mutation responsible for low-level nalidixic acid resistance in Neisseria gonorrhoeae

Nalidixic acid-resistant derivatives of Neisseria gonorrhoeae WR302 were identified and categorized into two classes on the basis of their susceptibilities to this antimicrobial agent. The MIC of nalidixic acid for the derivative strain MUG116 was fourfold greater than that for its isogenic parental strain WR302 (2 versus 0.5 micrograms/ml, respectively). MUG324 was significantly more resistant to nalidixic acid (greater than 64 micrograms/ml). The MICs of other antimicrobial agents known to interact with either the gyrA or gyrB gene products were determined. Although the nalidixic acid MIC for MUG116 increased, no significant increases in the MICs of other agents that interact with the gyrA gene product were seen. The MICs of all agents that interact with the gyrA gene product were significantly increased for MUG324. The gene that imparts low-level nalidixic acid resistance was cloned from strain MUG116. The DNA sequence of this gene was determined, and by comparing the deduced amino acid sequence with sequences of proteins in data bases, this protein was found to be approximately 70% homologous with the gyrB gene product of Escherichia coli.

JC virus antibody status underestimates infection rates

OBJECTIVE

JC virus (JCV) seropositivity is a risk factor for progressive multifocal leukoencephalopathy (PML) in patients on natalizumab. Accordingly, the JCV serological antibody test is of paramount importance in determining disease risk.

METHODS

We tested the accuracy of the JCV serum antibody test by comparing the results of JCV serology to JCV viruria and viremia in 67 patients enrolled in a single-center, retrospective cohort study. Bodily fluids (urine and blood) were assessed for JCV DNA by real time quantitative polymerase chain reaction 6 to 47 months (mean = 26.1 months) before JCV antibody testing. In 10 individuals, blood and urine samples were obtained on 2 separate occasions at 6-month intervals.

RESULTS

Forty (59.7%) of the 67 patients were JCV seropositive. Of 27 JCV seronegative patients, 10 (37%) had JCV viruria. Urine JCV DNA copy numbers were significantly higher in the seropositive group (mean log copy number = 5.93, range = 1.85-9.21) than the seronegative group (mean log copy number = 2.41, range = 1.85-5.43; p = 0.0026). Considering all body fluid test results, 50 (74.6%) of the 67 patients were previously infected with JCV.

INTERPRETATION

The false-negative rate of the JCV serology in this study was 37%; therefore, JCV serostatus does not appear to identify all patients infected with JCV. Thus, a negative JCV antibody result should not be conflated with absence of JCV infection. This discordance may be important in understanding JCV biology, risk for PML, and PML pathogenesis.

Histone deacetylase inhibitors induce reactivation of herpes simplex virus type 1 in a latency-associated transcript-independent manner in neuronal cells

Histone acetylation is implicated in the regulation of herpes simplex virus type 1 (HSV-1) latency. However, the role of histone acetylation in HSV-1 reactivation is less clear. In this study, the well-established model system, quiescently infected, neuronally differentiated PC12 (QIF-PC12) cells, was used to address the participation of histone acetylation in HSV-1 reactivation. In this model, sodium butyrate and trichostatin A (TSA), two histone deacetylase inhibitors, stimulated production of infectious HSV-1 progeny from a quiescent state. To identify viral genes responsive to TSA, the authors analyzed representative alpha, beta, and gamma viral genes using quantitative real-time polymerase chain reaction. Only the latency-associated transcript (LAT) accumulated in response to TSA treatment, under culture conditions that restricted virus replication and spread. This led the authors to evaluate the importance of LAT expression on TSA-induced reactivation. In QIF-PC12 cells, the LAT deletion mutant virus dLAT2903 reactivated equivalently with its wild-type parental strain (McKrae) after TSA treatment, as well as forskolin and heat stress treatment. Both viruses also reactivated equivalently from latently infected trigeminal ganglia explants from rabbits. In contrast, there was a marked reduction in the recovery of dLAT2903, as compared to wild-type virus, from the eyes of latently infected rabbits following epinephrine iontophoresis. These combined in vitro, ex vivo, and in vivo data suggest that LAT is not required for reactivation from latently infected neuronal cells per se, but may enhance processes that allow for the arrival of virus at, or close to, the site of original inoculation (i.e., recrudescence).

Molecular aspects of herpes simplex virus I latency, reactivation, and recurrence

The application of molecular biology in the study of the pathogenesis of herpes simplex virus type 1 (HSV-1) has led to significant advances in our understanding of mechanisms that regulate virus behavior in sensory neurons and epithelial tissue. Such study has provided insight into the relationship of host and viral factors that regulate latency, reactivation, and recurrent disease. This review attempts to distill decades of information involving human, animal, and cell culture studies of HSV-1 with the goal of correlating molecular events with the clinical and laboratory behavior of the virus during latency, reactivation, and recurrent disease. The purpose of such an attempt is to acquaint the clinician/scientist with the current thinking in the field, and to provide key references upon which current opinions rest.

Asymptomatic shedding of herpes simplex virus (HSV) in the oral cavity

OBJECTIVE

The aim of this study was to investigate the rate of herpes simplex virus (HSV) shedding from the oral cavity, because recent studies suggest that shedding is more frequent than originally reported. Factors that could influence the rate and duration of shedding from the oral cavity were examined.

METHODS

Existing epidemiologic data from 22 reports of HSV shedding from more than 3,500 individuals were analyzed with regard to demographics, frequency of sampling, and methodologic assays.

RESULTS

HSV-1 was more likely to be detected than HSV-2 in the oral cavity of asymptomatic persons (7.5 odds ratio, 95% confidence interval 4.4-12.8; P < .0001). The rate of shedding was highly variable among individuals, ranging from none to 92% of days tested, and occurred in seropositive and seronegative individuals. In cell culture studies, the rate of detection on a single day was 6.3%. Polymerase chain reaction studies provided a different picture. HSV-1 DNA was present in 97 of 180 patients (53.9%) at multiple visits, with a rate of daily detection of 33.3%. The mean duration of shedding was between 1 and 3 days, but more than 3 days in about 10% of patients.

CONCLUSIONS

At least 70% of the population shed HSV-1 asymptomatically at least once a month, and many individuals appear to shed HSV-1 more than 6 times per month. Shedding of HSV-1 is present at many intraoral sites, for brief periods, at copy numbers sufficient to be transmitted, and even in seronegative individuals. The dental implications of these findings are discussed.

Rapid assessment of salivary MMP-8 and periodontal disease using lateral flow immunoassay

OBJECTIVE

The objective of this study was to determine the efficacy of a novel point-of-care immunoflow device (POCID) for detecting matrix metalloproteinase (MMP)-8 concentrations in oral fluids in comparison with a gold standard laboratory-based immunoassay.

METHODS

Oral rinse fluid and whole expectorated saliva samples were collected from 41 participants clinically classified as periodontally healthy or diseased. Samples were analyzed for MMP-8 by Luminex immunoassay and POCID. Photographed POCID results were assessed by optical scan and visually by two examiners. Data were analyzed by Pearson's correlation and receiver-operating characteristics.

RESULTS

MMP-8 was readily detected by the POCID, and concentrations correlated well with Luminex for both saliva and rinse fluids (r = 0.57-0.93). Thresholds that distinguished periodontitis from health were delineated from both the optical scans and visual reads of the POCID (sensitivity: 0.7-0.9, specificity: 0.5-0.7; P < 0.05).

CONCLUSIONS

Performance of this POCID for detecting MMP-8 in oral rinse fluid or saliva was excellent. These findings help demonstrate the utility of salivary biomarkers for distinguishing periodontal disease from health using a rapid point-of-care approach.

Effect of prophylactic valacyclovir on the presence of human herpesvirus DNA in saliva of healthy individuals after dental treatment

Human herpesviruses (HHVs) are ubiquitous pathogens that intermittently reactivate from latency. Transmission is believed to be facilitated by their frequent appearance in saliva. This study sought to understand the factors that influence the appearance of these viruses in saliva by examining the prevalence, pattern, and quantity of all eight HHVs in saliva of immunocompetent adults with a history of recurrent oral herpes simplex virus (HSV) infections following dental treatment and antiviral therapy. Valacyclovir or matched placebo was given (2 g twice on the day of treatment and 1 g twice the following day) to 125 patients in a randomized, double-blind controlled trial. Saliva, collected on the day of dental treatment and 3 and 7 days later, was analyzed using real-time quantitative PCR. At all visits, HHVs coinfected saliva. Over the course of the week, the DNAs of HHV-6 and HHV-7 were detected significantly more often (97% to 99% of patients) than Epstein-Barr virus (EBV; 64.8%), HSV-1 (13.0%), HHV-8 (3.2%), cytomegalovirus (2.4%), HSV-2 (0%), and varicella-zoster virus (0%), irrespective of drug treatment (P < 0.002). Mean genome copy numbers were highest for HSV-1 and HHV-6. Dental treatment did not influence asymptomatic viral shedding patterns. However, valacyclovir treatment resulted in significantly fewer patients shedding EBV at both postoperative visits compared with placebo (P < 0.008). These results suggest that HHVs are simultaneously present in the saliva of healthy adults at levels that could facilitate transmission, and valacyclovir therapy decreases the prevalence of EBV in saliva but has little effect on HHV-6 and HHV-7.

Expression of miR-15/107 family microRNAs in human tissues and cultured rat brain cells

The miR-15/107 family comprises a group of 10 paralogous microRNAs (miRNAs), sharing a 5′ AGCAGC sequence. These miRNAs have overlapping targets. In order to characterize the expression of miR-15/107 family miRNAs, we employed customized TaqMan Low-Density micro-fluid PCR-array to investigate the expression of miR-15/107 family members, and other selected miRNAs, in 11 human tissues obtained at autopsy including the cerebral cortex, frontal cortex, primary visual cortex, thalamus, heart, lung, liver, kidney, spleen, stomach and skeletal muscle. miR-103, miR-195 and miR-497 were expressed at similar levels across various tissues, whereas miR-107 is enriched in brain samples. We also examined the expression patterns of evolutionarily conserved miR-15/107 miRNAs in three distinct primary rat brain cell preparations (enriched for cortical neurons, astrocytes and microglia, respectively). In primary cultures of rat brain cells, several members of the miR-15/107 family are enriched in neurons compared to other cell types in the central nervous system (CNS). In addition to mature miRNAs, we also examined the expression of precursors (pri-miRNAs). Our data suggested a generally poor correlation between the expression of mature miRNAs and their precursors. In summary, we provide a detailed study of the tissue and cell type-specific expression profile of this highly expressed and phylogenetically conserved family of miRNA genes.

Antigenic variation in Neisseria gonorrhoeae: production of multiple lipooligosaccharides

Individual cells of Neisseria gonorrhoeae may express a single lipooligosaccharide (LOS) component on their cell surfaces, or they may simultaneously express multiple LOS structures. Strain FA19 expresses LOS components that react with monoclonal antibodies (MAbs) 2-1-L8 and 1B2. The genetic locus responsible for this phenotype in FA19 was identified by isolating a clone that is able to impart the ability to simultaneously express both LOS molecules to strain 1291, a strain expressing only the MAb 1B2-reactive LOS. This clone, pCLB1, was characterized, and the gene responsible for the expression of both LOS components was determined to be lsi2. DNA sequence analysis of lsi2(Fa19) indicates that there are several differences between the DNA sequences of lsi2(FA19) and lsi2(1291). The region responsible for the LOS-specific phenotype change in lsi2(FA19) was identified by deletion and transformation analysis, mapping to a polyguanine tract within lsi2 where lsi2(FA19) possesses a +2 frameshift relative to lsi2(1291). The polyguanine tract in lsi2(FA19) was modified by site-directed mutagenesis to change the sequence to GGGAGGTGGCGGA to prevent frameshifting during DNA replication, transcription, and/or translation. Transformants of strain 1291 containing this DNA sequence express a single MAb 2-1-L8-reactive LOS component, the same phenotype exhibited by lsi2-defective strains. These data indicate that FA19 is able to generate a small amount of functional Lsi2 protein via transcriptional and/or translational frameshifting, and this limited amount of protein allows for the expression of MAb 1B2-reactive LOS molecules.

Establishment of a quiescent herpes simplex virus type 1 infection in neurally-differentiated PC12 cells

Rat pheochromocytoma (PC12) cells differentiated with nerve growth factor (Nd-PC12) were used to investigate the establishment of a non-productive herpes simplex virus type 1 (HSV-1) infection that is reversible. The results of this work are as follows: (i) Nd-PC12 cultures could be maintained as long term (>7 weeks) non-dividing cultures only when plated on collagen-coated dishes in the absence of serum; (ii) Infection of Nd-PC12 with HSV-1 strains KOS and 17 in the transient presence of acycloguanosine (ACV) resulted in all cultures free of detectable levels of infectious virus at the time of ACV removal and ACV was not needed to maintain the non-productive quiescent state in the subsequent 8 weeks; (iii) These persistently infected and quiescent (QIF)-PC12 cultures demonstrated both spontaneous and forskolin-inducible virus production, at low (5%) and high frequencies (92-100%), respectively during the first 2 weeks post-ACV withdrawal. (iv) In contrast to other in vitro models, HSV-1 failed to reactivate following removal of nerve growth factor. (v) A high percentage of QIF-PC12 cultures (50-100%) produced virus in response to forskolin treatment as long as 7 weeks post-ACV withdrawal. (vi) Expression of HSV-1 productive genes (i.e. alpha0, alpha4, alpha27, UL30 and UL18) dropped precipitously in the presence of ACV and remained undetectable or continued to decline following its removal, whereas the levels of LAT and the host gene G3PDH remained relatively constant throughout the 31 day study period as measured by RT-PCR. These results indicate that QIF-PC12 cells offer a novel, neuronal cell culture system that may enhance our ability to study HSV-1 reactivation from a cryptic, latent-like, non-productive state in the absence of replication inhibitors.

Antiviral effects of blackberry extract against herpes simplex virus type 1

OBJECTIVE

The aim of this study was to evaluate antiviral properties of blackberry extract against herpes simplex virus type 1 (HSV-1) in vitro.

STUDY DESIGN

HSV-infected oral epithelial (OKF6) cells and cell-free virus suspensions were treated with blackberry extract (2.24-1,400 μg/mL), and virus yield and infectivity were quantified by direct plaque assay.

RESULTS

Blackberry extract ≥56 μg/mL inhibited HSV-1 replication in oral epithelial cells by >99% (P < .005). Concentrations ≥280 μg/mL were antiviral when the extract was added after virus adsorption and entry. Exposure of cell-free virus to ≥280 μg/mL blackberry extract for 15 minutes at room temperature was virucidal (P = .0002). The virucidal effects were not due to pH changes at concentrations up to 1,500 μg/mL.

CONCLUSIONS

Blackberry extract inhibited the early stages of HSV-1 replication and had potent virucidal activity. These properties suggest that this natural fruit extract could provide advantage as a topical prophylactic/therapeutic agent for HSV infections.

Antibacterial effects of blackberry extract target periodontopathogens

BACKGROUND AND OBJECTIVE

Antimicrobial agents provide valuable adjunctive therapy for the prevention and the control of oral diseases. Limitations in their prolonged use have stimulated the search for new, naturally occurring agents with more specific activity and fewer adverse effects. Here we sought to determine the antibacterial properties of blackberry extract (BBE) in vitro against oral bacterial commensals and periodontopathogens.

MATERIAL AND METHODS

The effects of whole and fractionated BBE on the metabolism of 10 different oral bacteria were evaluated using the colorimetric water-soluble tetrazolium-1 assay. The bactericidal effects of whole BBE against Fusobacterium nucleatum were determined by quantitating the numbers of colony-forming units (CFUs). Cytotoxicity was determined in oral epithelial (OKF6) cells.

RESULTS

BBE at 350-1400 μg/mL reduced the metabolic activity of Porphyromonas gingivalis, F. nucleatum and Streptococcus mutans. The reduced metabolic activity observed for F. nucleatum corresponded to a reduction in the numbers of CFUs following exposure to BBE for as little as 1 h, indicative of its bactericidal properties. An anthocyanin-enriched fraction of BBE reduced the metabolic activity of F. nucleatum, but not of P. gingivalis or S. mutans, suggesting the contribution of species-specific agents in the whole BBE. Oral epithelial cell viability was not reduced following  exposure to whole BBE (2.24-1400 μg/mL) for ≤ 6 h.

CONCLUSION

BBE alters the metabolic activity of oral periodontopathogens while demonstrating a minimal effect on commensals. The specific antibacterial properties of BBE shown in this study, along with its previously demonstrated anti-inflammatory and antiviral properties, make this natural extract a promising target as an adjunct for prevention and/or complementary therapy of periodontal infections.

Histone deacetylase inhibitors prevent persistent hypersensitivity in an orofacial neuropathic pain model

Chronic orofacial pain is a significant health problem requiring identification of regulating processes. Involvement of epigenetic modifications that is reported for hindlimb neuropathic pain experimental models, however, is less well studied in cranial nerve pain models. Three independent observations reported here are the (1) epigenetic profile in mouse trigeminal ganglia (TG) after trigeminal inflammatory compression (TIC) nerve injury mouse model determined by gene expression microarray, (2) H3K9 acetylation pattern in TG by immunohistochemistry, and (3) efficacy of histone deacetylase (HDAC) inhibitors to attenuate development of hypersensitivity. After TIC injury, ipsilateral whisker pad mechanical sensitization develops by day 3 and persists well beyond day 21 in contrast to sham surgery. Global acetylation of H3K9 decreases at day 21 in ipsilateral TG . Thirty-four genes are significantly (p < 0.05) overexpressed in the ipsilateral TG by at least two-fold at either 3 or 21 days post-trigeminal inflammatory compression injury. The three genes most overexpressed three days post-trigeminal inflammatory compression nerve injury are nerve regeneration-associated gene ATF3, up 6.8-fold, and two of its regeneration-associated gene effector genes, Sprr1a and Gal, up 174- and 25-fold, respectively. Although transcription levels of 25 of 32 genes significantly overexpressed three days post-trigeminal inflammatory compression return to constitutive levels by day 21, these three regeneration-associated genes remain significantly overexpressed at the later time point. On day 21, when tissues are healed, other differentially expressed genes include 39 of the top 50 upregulated and downregulated genes. Remarkably, preemptive manipulation of gene expression with two HDAC inhibitors (HDACi's), suberanilohydroxamic acid (SAHA) and MS-275, reduces the magnitude and duration of whisker pad mechanical hypersensitivity and prevents the development of a persistent pain state. These findings suggest that trigeminal nerve injury leads to epigenetic modifications favoring overexpression of genes involved in nerve regeneration and that maintaining transcriptional homeostasis with epigenetic modifying drugs could help prevent the development of persistent pain.

Trigeminal Inflammatory Compression (TIC) injury induces chronic facial pain and susceptibility to anxiety-related behaviors

Our laboratory previously developed a novel neuropathic and inflammatory facial pain model for mice referred to as the Trigeminal Inflammatory Compression (TIC) model. Rather than inducing whole nerve ischemia and neuronal loss, this injury induces only slight peripheral nerve demyelination triggering long-term mechanical allodynia and cold hypersensitivity on the ipsilateral whisker pad. The aim of the present study is to further characterize the phenotype of the TIC injury model using specific behavioral assays (i.e. light-dark box, open field exploratory activity, and elevated plus maze) to explore pain- and anxiety-like behaviors associated with this model. Our findings determined that the TIC injury produces hypersensitivity 100% of the time after surgery that persists at least 21 weeks post injury (until the animals are euthanized). Three receptive field sensitivity pattern variations in mice with TIC injury are specified. Animals with TIC injury begin displaying anxiety-like behavior in the light-dark box preference and open field exploratory tests at week eight post injury as compared to sham and naïve animals. Panic anxiety-like behavior was shown in the elevated plus maze in mice with TIC injury if the test was preceded with acoustic startle. Thus, in addition to mechanical and cold hypersensitivity, the present study identified significant anxiety-like behaviors in mice with TIC injury resembling the clinical symptomatology and psychosocial impairments of patients with chronic facial pain. Overall, the TIC injury model's chronicity, reproducibility, and reliability in producing pain- and anxiety-like behaviors demonstrate its usefulness as a chronic neuropathic facial pain model.

ICP0 is not required for efficient stress-induced reactivation of herpes simplex virus type 1 from cultured quiescently infected neuronal cells

Viral genes sufficient and required for herpes simplex virus type 1 (HSV-1) reactivation were identified using neuronally differentiated PC12 cells (ND-PC12 cells) in which quiescent infections with wild-type and recombinant strains were established. In this model, the expression of ICP0, VP16, and ICP4 from adenovirus vectors was sufficient to reactivate strains 17+ and KOS. The transactivators induced similar levels of reactivation with KOS; however, 17+ responded more efficiently to ICP0. To identify viral transactivators required for reactivation, we examined quiescently infected PC12 cell cultures (QIF-PC12 cell cultures) established with HSV-1 deletion mutants R7910 (deltaICP0), KD6 (deltaICP4), and in1814, a virus containing an insertion mutation in VP16. Although growth of these mutant viruses was impaired in ND-PC12 cells, R7910 and in1814 reactivated at levels equivalent to or better than their respective parental controls following stress (i.e., heat or forskolin) treatment. After treatment with trichostatin A, in1814 and 17+ reactivated efficiently, whereas the F strain and R7910 reactivated inefficiently. In contrast, KD6 failed to reactivate. In experiments with the recombinant KM100, which contains the in1814 mutation in VP16 and the n212 mutation in ICP0, spontaneous and stress-induced reactivation was observed. However, two strains, V422 and KM110, which lack the acidic activation domain of VP16, did not reactivate above low spontaneous levels after stress. These results demonstrate that in QIF-PC12 cells ICP0 is not required for efficient reactivation of HSV-1, the acidic activation domain of VP16 is essential for stress-induced HSV-1 reactivation, and HSV-1 reactivation is modulated uniquely by different treatment constraints and phenotypes.

Analysis of the lsi region involved in lipooligosaccharide biosynthesis in Neisseria gonorrhoeae

The genetic locus (lsi-1) responsible for the transformation of the lipooligosaccharide (LOS)-defective Neisseria gonorrhoeae mutant FA5100 to LOS expression was studied by deletion mutagenesis and sequence analysis. An open reading frame that was preceded by a leader sequence containing regions with the potential to form hairpin loops was identified. A perfect sigma 70 promoter consensus sequence was found upstream from this open reading frame. Promoter function was screened for functionality by using lac fusion cassettes and in vitro transcription-translation analysis. A frameshift mutation in the lsi-1 gene was constructed by site-directed mutagenesis and introduced into the chromosome of FA19, the LOS-expressing isogenic parent strain of FA5100. The mutant was characterized by Southern blotting, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blotting (immunoblotting) and found to be phenotypically identical to FA5100.

Heat stress activates production of herpes simplex virus type 1 from quiescently infected neurally differentiated PC12 cells

We have previously described a novel in vitro model of a non-productive herpes simplex virus type 1 (HSV-1) infection in neurally differentiated (Nd)-PC12 cells that allows for inducible virus replication upon forskolin treatment. In this study, we further characterized the quiescent state of infection and examined the ability of heat stress (HS) to induce virus from this non-productive state. These studies demonstrated that (i) the quiescent state is characterized by the absence of cell-associated virus, capsids, and viral antigens; (ii) HS (43 degrees C, 3 h) efficiently activated virus from quiescently infected Nd-PC12 (QIF-PC12) cells; (iii) the rate of virus production was significantly greater following HS than forskolin treatment, and the rates of both were dependent on MOI; (iv) forskolin and HS appeared to affect pathways of viral activation from a quiescent state as they did not enhance viral growth in Nd-PC12 cells; (v) viral alpha4 gene and host HSP72 gene transcription were rapidly induced in QIF-PC12 as soon as 3 h post-HS initiation; (vi) induction of the viral alpha27 gene followed that of representative beta and gamma genes, U(L)30 and U(L)18, respectively, and (vii) HS induced asynchronous HSV-1 replication from QIF-PC12 cells with 1:400 to 1:22000 positive foci detected as rapid as 24 h post-induction when established at MOIs of 30 and 3, respectively. These findings provide evidence that alpha4 may be involved in the switch from quiescence to productive infection. Furthermore, this model has the potential to advance our understanding of how HS initiates the HSV-1 productive cycle from a cryptic viral genome.

Low prevalence of varicella zoster virus and herpes simplex virus type 2 in saliva from human immunodeficiency virus-infected persons in the era of highly active antiretroviral therapy

OBJECTIVES

Human herpesviruses, e.g., herpes simplex virus (HSV) type 1, Epstein-Barr virus, and cytomegalovirus, appear in saliva at greater frequency in persons infected with human immunodeficiency virus (HIV) than in healthy individuals. However, it is not known if varicella zoster virus (VZV) and HSV-2 appear simultaneously during HIV infection at greater frequency in saliva in this era of highly active antiretroviral therapy (HAART). The aim of this study was to investigate the prevalence and amounts of VZV and HSV-2 in the saliva of HIV-infected orally asymptomatic patients.

STUDY DESIGN

Quantitative polymerase chain reaction was used to investigate the prevalence, quantity, risk, and correlations of salivary VZV and HSV-2 from 59 HIV-seropositive individuals and 53 healthy control subjects in a case-control cross-sectional study. Seventy-eight percent of the HIV-seropositive patients (46 out of 59) were taking HAART.

RESULTS

VZV DNA was detected in the saliva of 5.1% (3 out of 59) of the HIV-positive group and in only 1 healthy control 1.9% (1 out of 53; P = .62). The amount of VZV DNA in the expressors was low, generally <1,100 copies/mL, with no observed difference between the HIV-positive group and the control subjects (P = 1.0). HSV-2 DNA was not detected in either group. In the HIV-infected group, VZV shedding occurred in those on HAART, but was not associated with oral lesions, specific CD4(+) or CD8(+) T-cell levels, or demographic factors.

CONCLUSIONS

Varicella zoster virus was detected at low prevalence in the saliva of HIV-infected persons, whereas HSV-2 was not detected in the saliva of this cohort. HAART does not appear to diminish the risk for asymptomatic VZV shedding.

Genetic basis of pyocin resistance in Neisseria gonorrhoeae

The genetic basis for pyocin resistance in Neisseria gonorrhoeae 1291d, 1291e, and FA5100 was determined by Southern blot and DNA sequence analyses. The genes defective in these strains are present as single copies in the gonococcal chromosome. The mutant regions of 1291d, 1291e, and FA5100 were amplified by the PCR. Sequence analysis of the mutant regions demonstrated that strain 1291d contains a 12-bp deletion that results in the loss of four amino acids in phosphoglucomutase, while strain 1291e contains a point mutation that results in the change of an uncharged glycine residue to a charged glutamic acid residue in the same protein. FA5100 contains a nonsense mutation in the gene encoding heptosyltransferase II. The gene previously described as lsi-1 was shown to complement an rfaF mutation in Salmonella typhimurium and has been renamed rfaF.

Herpesvirus quiescence in neuronal cells IV: virus activation induced by pituitary adenylate cyclase-activating polypeptide (PACAP) involves the protein kinase A pathway

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a naturally occurring peptide found in the central nervous system that plays a role in somatosensory processing and activation of protein kinase A (PKA) and protein kinase C (PKC). Because activation of PKA or PKC results in reactivation of HSV-1 from latently infected embryonic neuronal cells, PACAP was used to evaluate HSV-1 activation from quiescently infected (QIF)-PC12 cells. Our studies demonstrate that physiologically relevant concentrations of PACAP38 and PACAP27 induce HSV-1 activation from QIF-PC12 cell cultures in a dose-dependent fashion. PACAP-induced activation of virus was significantly impaired by the PKA-inhibitor, H-89 (20 microM), whereas treatment with the PKC-inhibitor, GF109203X (1 microM), was without affect. Additionally, direct activation of PKA with cAMP analogs, 8-(4-chlorophenylthio)- and dibutyryl-cAMP, only partially mimicked the effect of PACAP on virus activation. Taken together, PACAP induced HSV-1 activation from QIF-PC12 cells involves the PKA and possibly cAMP-independent pathways. This report is the first to demonstrate that PACAP induces HSV-1 activation from a quiescent state and that this in vitro cell model is useful for studying early inductive events that lead to virus production from quiescence.

Combination Drug Therapy of Pioglitazone and D-cycloserine Attenuates Chronic Orofacial Neuropathic Pain and Anxiety by Improving Mitochondrial Function Following Trigeminal Nerve Injury

OBJECTIVES

The study aim was to determine how peripheral trigeminal nerve injury affects mitochondrial respiration and to test efficacy of combined treatment with 2 Federal Drug Administration approved drugs with potential for improving mitochondrial bioenergetics, pain and anxiety-related behaviors in a chronic orofacial neuropathic pain mouse model.

METHODS

Efficacy of (R)-(+)-4-amino-3-isoxazolidinone (D-cycloserine, DCS), an N-Methyl-D-aspartate antagonist/agonist, and Pioglitazone (PIO), a selective agonist of nuclear receptor peroxisome proliferator-activated receptor gamma was investigate in the trigeminal inflammatory compression (TIC) neuropathic nerve injury mouse model. Combined low doses of these drugs (80 mg/kg DCS and 100 mg/kg PIO) were given as a single bolus or daily for 7 days post-TIC to test ability to attenuate neuropathic nociceptive and associated cognitive dependent anxiety behaviors. In addition, beneficial effects of the DCS/PIO drug combination were explored ex vivo in isolated cortex/brainstem mitochondria at 28 weeks post-TIC.

RESULTS

The DCS/PIO combination not only attenuated orofacial neuropathic pain and anxiety-related behaviors associated with trigeminal nerve injury, but it also improved mitochondrial bioenergetics.

DISCUSSION

The DCS/PIO combination uncoupled mitochondrial respiration in the TIC model to improve cortical mitochondrial dysfunction, as well as reduced nociceptive and anxiety behaviors present in mice with centralized chronic neuropathic nerve injury. Combining these drugs could be a beneficial treatment for patients with depression, anxiety, or other psychological conditions due to their chronic pain status.