bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lysine-Enriched Cecropin-Mellitin Antimicrobial Peptides with Enhanced Selectivity
Authors: Sato Hiromi , Feix Jimmy B. 
Published: October 2008

ABSTRACTLysine-enriched analogs of the cecropin-mellitin hybrid peptide, CA1-7M2-9(designated CM15), designed with optimized amphipathicity, retained antimicrobial activities similar to that of wild-type CM15 and had substantially reduced levels of hemolytic activity and cytotoxicity toward cultured macrophages, resulting in enhanced selectivity. These lysine-enriched analogs provide templates for improved CM15 peptide or peptidomimetic antibiotics.
Inhibition of Herpesvirus Replication by Hexadecyloxypropyl Esters of Purine- and Pyrimidine-Based Phosphonomethoxyethyl Nucleoside Phosphonates
Authors: Prichard Mark N. , Hartline Caroll B. , Harden Emma A. , Daily Shannon L. , Beadle James R. , Valiaeva Nadejda , Kern Earl R. , Hostetler Karl Y. 
Published: October 2008

ABSTRACT
Patients infected with human immunodeficiency virus (HIV) often suffer from herpesvirus infections as a result of immunosuppression. These infections can occur while patients are receiving antiretroviral therapy, and additional drugs required to treat their infection can adversely affect compliance. It would be useful to have antivirals with a broader spectrum of activity that included both HIV and the herpesviruses. We reported previously that alkoxyalkyl ester prodrugs of cidofovir are up to 3 orders of magnitude more active against herpesvirus replication and may be less toxic than the unmodified drug. To determine if this strategy would be effective for certain phosphonomethoxyethyl nucleoside phosphonates which are also active against HIV infections, the hexadecyloxypropyl (HDP) esters of 1-(phosphonomethoxyethyl)-cytosine, 1-(phosphonomethoxyethyl)-5-bromo-cytosine (PME-5BrC), 1-(phosphonomethoxyethyl)-5-fluoro-cytosine, 9-(phosphonomethoxyethyl)-2,6-diaminopurine (PME-DAP), and 9-(phosphonomethoxyethyl)-2-amino-6-cyclopropylaminopurine (PME-cPrDAP) were evaluated for activity against herpesvirus replication. The HDP esters were substantially more active than the unmodified acyclic nucleoside phosphonates, indicating that esterification with alkoxyalkyl groups increases the antiviral activity of many acyclic nucleoside phosphonates. The most interesting compounds included HDP-PME-cPrDAP and HDP-PME-DAP, which were 12- to 43-fold more active than the parent nucleoside phosphonates against herpes simplex virus and cytomegalovirus, and HDP-PME-cPrDAP and HDP-PME-5BrC which were especially active against Epstein-Barr virus. The results presented here indicate that HDP-esterified acyclic nucleoside phosphonates with antiviral activity against HIV also inhibit the replication of some herpesviruses and can extend the spectrum of activity for these compounds.
Gene Therapy Using Adeno-Associated Virus Vectors
Authors: Daya Shyam , Berns Kenneth I. 
Published: October 2008

SUMMARY
The unique life cycle of adeno-associated virus (AAV) and its ability to infect both nondividing and dividing cells with persistent expression have made it an attractive vector. An additional attractive feature of the wild-type virus is the lack of apparent pathogenicity. Gene transfer studies using AAV have shown significant progress at the level of animal models; clinical trials have been noteworthy with respect to the safety of AAV vectors. No proven efficacy has been observed, although in some instances, there have been promising observations. In this review, topics in AAV biology are supplemented with a section on AAV clinical trials with emphasis on the need for a deeper understanding of AAV biology and the development of efficient AAV vectors. In addition, several novel approaches and recent findings that promise to expand AAV's utility are discussed, especially in the context of combining gene therapy ex vivo with new advances in stem or progenitor cell biology.
Detection of Respiratory Viruses by Molecular Methods
Authors: Mahony James B. 
Published: October 2008

SUMMARY
Clinical laboratories historically diagnose seven or eight respiratory virus infections using a combination of techniques including enzyme immunoassay, direct fluorescent antibody staining, cell culture, and nucleic acid amplification tests. With the discovery of six new respiratory viruses since 2000, laboratories are faced with the challenge of detecting up to 19 different viruses that cause acute respiratory disease of both the upper and lower respiratory tracts. The application of nucleic acid amplification technology, particularly multiplex PCR coupled with fluidic or fixed microarrays, provides an important new approach for the detection of multiple respiratory viruses in a single test. These multiplex amplification tests provide a sensitive and comprehensive approach for the diagnosis of respiratory tract infections in individual hospitalized patients and the identification of the etiological agent in outbreaks of respiratory tract infection in the community. This review describes the molecular methods used to detect respiratory viruses and discusses the contribution that molecular testing, especially multiplex PCR, has made to our ability to detect respiratory viruses and to increase our understanding of the roles of various viral agents in acute respiratory disease.
Identification of a Surrogate Marker for Infection in the African Green Monkey Model of Inhalation Anthrax
Authors: Rossi Cynthia A. , Ulrich Melanie , Norris Sarah , Reed Douglas S. , Pitt Louise M. , Leffel Elizabeth K. 
Published: October 2008

ABSTRACT

In 2001, a bioterrorism attack involving
Bacillus anthracis
spore-laced letters resulted in 22 cases of inhalation anthrax, with five fatalities. This incident identified gaps in our health care system and precipitated a renewed interest in identifying both therapeutics and rapid diagnostic assays. To address those gaps, well-characterized animal models that resemble the human disease are needed. In addition, a rapid assay for a reliable diagnostic marker is key to the success of these efforts. In this study, we exposed African green monkeys to
B. anthracis
spores; examined clinical signs and physiological parameters, including fever, heart rate, complete blood count, and bacteremia; and evaluated the PCR assay and electrochemiluminescence (ECL) immunoassay for the biomarkers protective antigen and capsule. The results demonstrated that although there were neither objective clinical nor physiological signs that consistently identified either infection or the onset of clinical anthrax disease, the African green monkey is a suitable animal model exhibiting a disease course similar to that observed in the rhesus model and humans. We also demonstrated that detection of the biomarkers protective antigen and capsule correlated with bacterial loads in the blood of these nonhuman primates. The ECL immunoassay described here is simple and sensitive enough to provide results in one to two hours, making this assay a viable option for use in the diagnosis of anthrax, leading to timely initiation of treatment, which is a key component of
B. anthracis
therapeutic development.
A Conserved C-Terminal 13-Amino-Acid Motif of Gap1 Is Required for Gap1 Function and Necessary for the Biogenesis of a Serine-Rich Glycoprotein ofStreptococcus parasanguinis
Authors: Zhou Meixian , Peng Zhixiang , Fives-Taylor Paula , Wu Hui 
Published: October 2008

ABSTRACTAdhesion ofStreptococcus parasanguinisto saliva-coated hydroxyapatite (SHA), an in vitro tooth model, is mediated by long peritrichous fimbriae. Fap1, a fimbria-associated serine-rich glycoprotein, is required for fimbrial assembly. Biogenesis of Fap1 is controlled by an 11-gene cluster that containsgly,nss,galT1and -2,secY2,gap1to -3,secA2, andgtf1and -2. We had previously isolated a collection of nine nonadherent mutants using random chemical mutagenesis approaches. These mutants fail to adhere to the in vitro tooth model and to form fimbriae. In this report, we further characterized these randomly selected nonadherent mutants and classified them into three distinct groups. Two groups of genes were previously implicated in Fap1 biogenesis. One group has a mutation in a glycosyltransferase gene,gtf1, that is essential for the first step of Fap1 glycosylation, whereas the other group has defects in thefap1structural gene. The third group mutant produces an incompletely glycosylated Fap1 and exhibits a mutant phenotype similar to that of a glycosylation-associated protein 1 (Gap1) mutant. Analysis of this new mutant revealed that a conserved C-terminal 13-amino-acid motif was missing in Gap1. Site-directed mutagenesis of a highly conserved amino acid tryptophan within this motif recapitulated the deletion phenotype, demonstrating the importance of the Gap1 C-terminal motif for Fap1 biogenesis. Furthermore, the C-terminal mutation does not affect Gap1-Gap3 protein-protein interaction, which has been shown to mediate Fap1 glycosylation, suggesting the C-terminal motif has a distinct function related to Fap1 biogenesis.
Evidence for Pore Formation in Host Cell Membranes by ESX-1-Secreted ESAT-6 and Its Role in
Mycobacterium marinum
Escape from the Vacuole
Authors: Smith Jennifer , Manoranjan Joanna , Pan Miao , Bohsali Amro , Xu Junjie , Liu Jun , McDonald Kent L. , Szyk Agnieszka , LaRonde-LeBlanc Nicole , Gao Lian-Yong 
Published: October 2008

ABSTRACT

The ESX-1 secretion system plays a critical role in the virulence of
M. tuberculosis
and
M. marinum
, but the precise molecular and cellular mechanisms are not clearly defined. Virulent
M. marinum
is able to escape from the
Mycobacterium
-containing vacuole (MCV) into the host cell cytosol, polymerize actin, and spread from cell to cell. In this study, we have examined nine
M. marinum
ESX-1 mutants and the wild type by using fluorescence and electron microscopy detecting MCV membranes and actin polymerization. We conclude that ESX-1 plays an essential role in
M. marinum
escape from the MCV. We also show that the ESX-1 mutants acquire the ability to polymerize actin after being artificially delivered into the macrophage cytosol by hypotonic shock treatment, indicating that ESX-1 is not directly involved in initiation of actin polymerization. We provide evidence that
M. marinum
induces membrane pores ∼4.5 nm in diameter, and this activity correlates with ESAT-6 secretion. Importantly, purified ESAT-6, but not the other ESX-1-secreted proteins, is able to cause dose-dependent pore formation in host cell membranes. These results suggest that ESAT-6 secreted by
M. marinum
ESX-1 could play a direct role in producing pores in MCV membranes, facilitating
M. marinum
escape from the vacuole and cell-to-cell spread. Our study provides new insight into the mechanism by which ESX-1 secretion and ESAT-6 enhance the virulence of mycobacterial infection.
The Early Phagosomal Stage of
Francisella tularensis
Determines Optimal Phagosomal Escape and
Francisella
Pathogenicity Island Protein Expression
Authors: Chong Audrey , Wehrly Tara D. , Nair Vinod , Fischer Elizabeth R. , Barker Jeffrey R. , Klose Karl E. , Celli Jean 
Published: October 2008

ABSTRACT

Francisella tularensis
is an intracellular pathogen that can survive and replicate within macrophages. Following phagocytosis and transient interactions with the endocytic pathway,
F. tularensis
rapidly escapes from its original phagosome into the macrophage cytoplasm, where it eventually replicates. To examine the importance of the nascent phagosome for the
Francisella
intracellular cycle, we have characterized early trafficking events of the
F. tularensis
subsp.
tularensis
strain Schu S4 in a murine bone marrow-derived macrophage model. Here we show that early phagosomes containing Schu S4 transiently interact with early and late endosomes and become acidified before the onset of phagosomal disruption. Inhibition of endosomal acidification with the vacuolar ATPase inhibitor bafilomycin A1 or concanamycin A prior to infection significantly delayed but did not block phagosomal escape and cytosolic replication, indicating that maturation of the early
Francisella
-containing phagosome (FCP) is important for optimal phagosomal escape and subsequent intracellular growth. Further,
Francisella
pathogenicity island (FPI) protein expression was induced during early intracellular trafficking events. Although inhibition of endosomal acidification mimicked the early phagosomal escape defects caused by mutation of the FPI-encoded IglCD proteins, it did not inhibit the intracellular induction of FPI proteins, demonstrating that this response is independent of phagosomal pH. Altogether, these results demonstrate that early phagosomal maturation is required for optimal phagosomal escape and that the early FCP provides cues other than intravacuolar pH that determine intracellular induction of FPI proteins.
Identification of Concomitant Infection with
Chlamydia trachomatis
IncA-Negative Mutant and Wild-Type Strains by Genomic, Transcriptional, and Biological Characterizations
Authors: Suchland Robert J. , Jeffrey Brendan M. , Xia Minsheng , Bhatia Ajay , Chu Hencelyn G. , Rockey Daniel D. , Stamm Walter E. 
Published: October 2008

ABSTRACT

Clinical isolates of
Chlamydia trachomatis
that lack IncA on their inclusion membrane form nonfusogenic inclusions and have been associated with milder, subclinical infections in patients. The molecular events associated with the generation of IncA-negative strains and their roles in chlamydial sexually transmitted infections are not clear. We explored the biology of the IncA-negative strains by analyzing their genomic structure, transcription, and growth characteristics in vitro and in vivo in comparison with IncA-positive
C. trachomatis
strains. Three clinical samples were identified that contained a mixture of IncA-positive and -negative same-serovar
C. trachomatis
populations, and two more such pairs were found in serial isolates from persistently infected individuals. Genomic sequence analysis of individual strains from each of two serovar-matched pairs showed that these pairs were very similar genetically. In contrast, the genome sequence of an unmatched IncA-negative strain contained over 5,000 nucleotide polymorphisms relative to the genome sequence of a serovar-matched but otherwise unlinked strain. Transcriptional analysis, in vitro culture kinetics, and animal modeling demonstrated that IncA-negative strains isolated in the presence of a serovar-matched wild-type strain are phenotypically more similar to the wild-type strain than are IncA-negative strains isolated in the absence of a serovar-matched wild-type strain. These studies support a model suggesting that a change from an IncA-positive strain to the previously described IncA-negative phenotype may involve multiple steps, the first of which involves a translational inactivation of
incA
, associated with subsequent unidentified steps that lead to the observed decrease in transcript level, differences in growth rate, and differences in mouse infectivity.
Human α- and β-Defensins Bind to Immobilized Adhesins fromPorphyromonas gingivalis
Authors: Dietrich Deborah E. , Xiao Xiangjun , Dawson Deborah V. , Bélanger Myriam , Xie Hua , Progulske-Fox Ann , Brogden Kim A. 
Published: October 2008

ABSTRACTHuman neutrophil peptide α-defensins (HNPs) and human β-defensins (HBDs) are small well-characterized peptides with broad antimicrobial activities and a diversity of innate immune functions. Although the interactions of defensins with bacteria and their membranes have been well characterized, the interactions of defensins with bacterial adhesins have not. Here we determine if HNPs and HBDs bind to the immobilized adhesins ofPorphyromonas gingivalisstrain 381, recombinant hemagglutinin B (rHagB) and recombinant fimbrillin A (rFimA), by surface plasmon resonance spectroscopy. Association of HNPs and HBDs with rHagB or rFimA was dose dependent and defensin specific. HBD3, HNP-2, and HNP-1 bound more readily to immobilized rHagB than HBD2 and HBD1 did. HNP-2, HNP-1, and HBD3 bound more readily to immobilized rFimA than HBD1 and HBD2 did. Binding of defensins to adhesins may serve to prevent microbial adherence to tissues, attenuate proinflammatory cytokine responses, and facilitate delivery of bound antigen to antigen-presenting cells with defensin receptors.
Colony-Stimulating Factor-1-Dependent Macrophage Functions Regulate the Maternal Decidua Immune Responses againstListeria monocytogenesInfections during Early Gestation in Mice
Authors: Qiu Xuan , Zhu Liyin , Pollard Jeffrey W. 
Published: October 2008

ABSTRACTThe association between extreme-prematurity births and intrauterine infection emphasizes the importance of understanding the host immune responses against uterine-invading microbes during early pregnancy to the prevention of preterm births.Listeria monocytogenes, a clinically relevant intracellular bacterium, has a predilection for replication at the maternofetal interface during pregnancy. Here, using mice carrying the recessive null osteopetrotic mutation in the colony-stimulating factor-1 (CSF-1) gene, we show that CSF-1-dependent macrophage functions are required for the maternal decidua immune responses againstL. monocytogenesinfections during early gestation in mice. In the absence of CSF-1, pregnant mice were more susceptible to uterine infection byL. monocytogenes; their inability to control the expansion of colonized bacteria in the pregnant uterus led to decidual cell death, tissue disintegration, and resorption of the developing embryo. However, CSF-1-deficient mice were able to produce significant levels of both Th1 cytokines and neutrophil chemoattractants and to recruit neutrophils to the decidual tissue in response toListeriainfection. Depletion of macrophages in hormonally induced pseudopregnant mice resulted in higher uterine bacterial levels afterL. monocytogenesinfection. These data suggest that the anti-Listeriaresponses in the maternal decidual tissue are dependent on CSF-1-regulated macrophages.
Isolation, Synthesis, and Antimicrobial Activities of Naturally Occurring θ-Defensin Isoforms from Baboon Leukocytes
Authors: Garcia Angie E. , Ösapay George , Tran Patti A. , Yuan Jun , Selsted Michael E. 
Published: October 2008

ABSTRACTθ-Defensins are macrocyclic antimicrobial peptides that were previously isolated from leukocytes of a single species, the rhesus macaque. We now report the characterization of baboon θ-defensins (BTDs) expressed in bone marrow and peripheral blood leukocytes. Four cDNAs encoding θ-defensin precursors were characterized, allowing for the prediction of 10 theoretical θ-defensins (BTD-1 to BTD-10) produced by binary, head-to-tail splicing of nonapeptides excised from paired precursors. Five of the predicted θ-defensins were purified from baboon leukocytes, and synthetic versions of each were prepared. Anti-θ-defensin antibody localized the peptides in circulating neutrophils and monocytes and in immature and mature myeloid elements in bone marrow. Each of the BTDs possessed antimicrobial activity against bacterial and fungal test organisms in vitro. Peptide activities varied markedly despite a high degree of sequence conservation among the θ-defensins tested. Thus, baboons express numerous θ-defensins which appear to differentially contribute to host defense against diverse pathogens.
Infected-Host-Cell Repertoire and Cellular Response in the Lung following Inhalation ofFrancisella tularensisSchu S4, LVS, or U112
Authors: Hall Joshua D. , Woolard Matthew D. , Gunn Bronwyn M. , Craven Robin R. , Taft-Benz Sharon , Frelinger Jeffrey A. , Kawula Thomas H. 
Published: October 2008

ABSTRACTFrancisella tularensiscauses systemic disease in humans and other mammals, with high morbidity and mortality associated with inhalation-acquired infection.F. tularensisis a facultative intracellular pathogen, but the scope and significance of cell types infected during disease is unknown. Using flow cytometry, we identified and quantified infected-cell types and assessed the impact of infection on cell populations following inhalation ofF. tularensisstrains U112, LVS, and Schu S4. Initially, alveolar macrophages comprised over 70% of Schu S4- and LVS-infected cells, whereas approximately 51% and 27% of U112-infected cells were alveolar macrophages and neutrophils, respectively. After 3 days, roughly half of Schu S4- and LVS- and nearly 80% of U112-infected cells were neutrophils. All strains infected CD11bhighmacrophages, dendritic cells, monocytes, and alveolar type II cells throughout infection. Macrophage, monocyte, and dendritic-cell populations were reduced during U112 infection but not Schu S4 or LVS infection. These results demonstrate directly thatF. tularensisis a promiscuous intracellular pathogen in the lung that invades and replicates within cell types ranging from migratory immune cells to structural tissue cells. However, the proportions of cell types infected and the cellular immune response evoked by the human pathogenic strain Schu S4 differ from those of the human avirulent U112.
Purification and characterization of 3,4-dihydroxyphenylalanine oxidative deaminase fromRhodobacter sphaeroidesOU5
Authors: Ranjith N. K. , Ramana Ch. V. , Sasikala Ch. 
Published: October 2008

An enzyme involved in the catabolism of 3,4-dihydroxyphenylalanine (DOPA) was isolated from Rhodobacter sphaeroides OU5. The enzyme catalyzes the formation of 3,4-dihydroxyphenylpyruvic acid (DOPP) and ammonia from DOPA. Formation of ammonia by DOPA oxidative deaminase was O2dependent and the enzyme isolated to its homogeneity has 100% affinity for DOPA. DOPA oxidative deaminase is functional at low concentrations of the substrate (<100 μmol·L–1) and is independent of NADH. The molecular mass of the purified enzyme is ~190 kDa and the enzyme could be a pentamer of 54, 42, 34, 25, and 23 kDa subunits as determined by SDS–PAGE.
Oral immunization with recombinant Lactococcus lactis confers protection against respiratory pneumococcal infection
Authors: Villena Julio , Medina Marcela , Raya Raúl , Alvarez Susana 
Published: October 2008

In the present work, we evaluated if oral immunization with the pneumococcal protective protein A (PppA), expressed in the cell wall of Lactococcus lactis (L. lactis PppA+), was able to confer protective immunity against Streptococcus pneumoniae . Mice were immunized orally with L. lactis PppA+ for 5 consecutive days. Vaccination was performed one (nonboosted group) or 2 times with a 2 week interval between each immunization (boosted group). Oral priming with L. lactis PppA+ induced the production of anti-PppA IgM, IgG, and IgA antibodies in serum and in bronchoalveolar (BAL) and intestinal (IF) lavage fluids. Boosting with L. lactis PppA+ increased the levels of mucosal and systemic immunoglobulins. Moreover, the avidity and the opsonophagocytic activity of anti-PppA antibodies were significantly improved in the boosted group. The presence of both IgG1 and IgG2a anti-PppA antibodies in serum and BAL and the production of both interferon γ and interleukin-4 by spleen cells from immunized mice indicated that L. lactis PppA+ stimulated a mixture of Th1 and Th2 responses. The ability of L. lactis PppA+ to confer cross-protective immunity was evaluated using challenge assays with serotypes 3, 6B, 14, and 23F. Lung bacterial cell counts and hemocultures showed that immunization with L. lactis PppA+ improved resistance against all the serotypes assessed, including serotype 3, which was highly virulent in our experimental animal model. To our knowledge, this is the first demonstration of protection against respiratory pneumococcal infection induced by oral administration of a recombinant lactococcal vaccine.