bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determinants for the Subcellular Localization and Function of a Nonessential SEDS Protein
Authors: Real Gonçalo , Fay Allison , Eldar Avigdor , Pinto Sérgio M. , Henriques Adriano O. , Dworkin Jonathan 
Published: November 2007

ABSTRACTTheBacillus subtilisSpoVE integral membrane protein is essential for the heat resistance of spores, probably because of its involvement in spore peptidoglycan synthesis. We found that an SpoVE-yellow fluorescent protein (YFP) fusion protein becomes localized to the forespore during the earliest stages of engulfment, and this pattern is maintained throughout sporulation. SpoVE belongs to a well-conserved family of proteins that includes the FtsW and RodA proteins ofB. subtilis. These proteins are involved in bacterial shape determination, although their function is not known. FtsW is necessary for the formation of the asymmetric septum in sporulation, and we found that an FtsW-YFP fusion localized to this structure prior to the initiation of engulfment in a nonoverlapping pattern with SpoVE-cyan fluorescent protein. Since FtsW and RodA are essential for normal growth, it has not been possible to identify loss-of-function mutations that would greatly facilitate analysis of their function. We took advantage of the fact that SpoVE is not required for growth to obtain point mutations in SpoVE that block the development of spore heat resistance but that allow normal protein expression and targeting to the forespore. These mutant proteins will be invaluable tools for future experiments aimed at elucidating the function of members of the SEDS (“shape, elongation, division, and sporulation”) family of proteins.
The GntR-Like Regulator TauR Activates Expression of Taurine Utilization Genes in
Rhodobacter capsulatus
Authors: Wiethaus Jessica , Schubert Britta , Pfänder Yvonne , Narberhaus Franz , Masepohl Bernd 
Published: November 2007

ABSTRACT

Rhodobacter capsulatus
can efficiently grow with taurine as the sole sulfur source. The products of the
tpa
-
tauR
-
xsc
gene region are essential for this activity. TauR, a MocR-like member of the GntR superfamily of transcriptional regulators, activates
tpa
transcription, as shown by analysis of wild-type and
tauR
mutant strains carrying a
tpa
-
lacZ
reporter fusion. Activation of the
tpa
promoter requires taurine but is not inhibited by sulfate, which is the preferred sulfur source. TauR directly binds to the
tpa
promoter, as demonstrated by DNA mobility shift assays. As expected for a transcriptional activator, the TauR binding site is located upstream of the transcription start site, which has been determined by primer extension. Site-directed promoter mutations reveal that TauR binds to direct repeats, an unusual property that has to date been shown for only one other member of the MocR subfamily, namely, GabR from
Bacillus subtilis
. In contrast, all other members of the GntR family analyzed so far bind to inverted repeats.
Processing of
as
-
48ABC
RNA in AS-48 Enterocin Production by
Enterococcus faecalis
Authors: Fernández Matilde , Sánchez-Hidalgo Marina , García-Quintáns Nieves , Martínez-Bueno Manuel , Valdivia Eva , López Paloma , Maqueda Mercedes 
Published: November 2007

ABSTRACT

Enterocin AS-48 production and immunity characters are encoded by 10 genes (
as
-

48ABCC
1
DD
1
EFGH

) of the pMB2 plasmid from the
Enterococcus faecalis
S-48 strain. Among these,
as
-
48A
, encoding the AS-48 peptide, and the
as
-
48BC
genes constitute a cluster required for AS-48 biogenesis and full immunity. In this study, the levels of expression of this cluster have been altered by insertion and site-directed mutagenesis as well as by expression coupled to
trans
complementation. Phenotypic studies of the mutants have indicated cotranscription of the three genes and revealed that the inactivation of
as
-
48B
prevents the production of AS-48, thus confirming its essentiality in AS-48 biogenesis. These studies have also supported the involvement of
as
-
48C
in enterocin immunity. In addition, they established that the intergenic region between the
as
-
48A
and
as
-
48B
genes is decisive for AS-48 expression, since a 3-bp substitution, which should disrupt a potential 47-nucleotide complex secondary structure, resulted in a hypoproducing phenotype. Transcriptional analyses of the
E. faecalis
wild-type and mutant strains supports the possibility that the
as
-
48ABC
genes are transcribed from the P

A

promoter located upstream of
as
-
48A
. Moreover, analysis and bioinformatic predictions of RNA folding indicate that
as
-
48ABC
mRNA is processed at the secondary structure located between
as
-
48A
and
as
-
48B
. Thus, synthesis of the AS-48 peptide appears to be controlled at the posttranscriptional level and is uncoupled from
as
-
48BC
translation. This mechanism of genetic regulation has not been previously described for the regulation of bacteriocin expression in enterococci.
PhaP Is Involved in the Formation of a Network on the Surface of Polyhydroxyalkanoate Inclusions in
Cupriavidus necator
H16
Authors: Dennis Douglas , Sein Vicki , Martinez Edgar , Augustine Brian 
Published: November 2007

ABSTRACT

Polyhydroxyalkanoate (PHA) inclusions are polymeric storage inclusions formed in some bacterial species when carbon levels are high but levels of another essential nutrient, such as nitrogen, are low. Though much is known about PHA synthesis, little is known about inclusion structure. In this study, atomic force microscopy (AFM) was employed to elucidate the structure of PHA inclusions at the nanoscale level, including the characterization of different layers of structure. AFM data suggest that underneath the inclusion envelope, there is a 2- to 4-nm-thick network layer that resides on top of a harder layer that is likely to be a crystalline lamellar polymer. The network is comprised of ∼20-nm-wide linear segments and junctions that are typically formed by the joining of three to four of the linear segments. In some cases, ∼50-nm globular structures that are raised ∼1 to 2 nm above the network are present at the junctions. These globular structures always have a central pore that is ∼15 nm in diameter. To determine if the major surface protein of PHA inclusions, PhaP, is involved in the structure of this network, inclusions from
Cupriavidus necator
H16 Δ
phaP
were examined. No network structure was detected. Instead, apparently random globular structures were found on the surfaces of the inclusions. When PhaP levels were reconstituted in this strain by the addition of
phaP
on a plasmid, the network was also reconstituted, albeit in a slightly different arrangement from that of the wild-type network. We conclude that PhaP participates in the formation of the inclusion network.
Primary Culture of
Mycobacterium ulcerans
from Human Tissue Specimens after Storage in Semisolid Transport Medium
Authors: Eddyani Miriam , Debacker Martine , Martin Anandi , Aguiar Julia , Johnson Christian R. , Uwizeye Cécile , Fissette Krista , Portaels Françoise 
Published: November 2007

ABSTRACT

Tissue specimens collected from patients with clinically suspected Buruli ulcer treated in two Buruli ulcer treatment centers in Benin between 1998 and 2004 were placed in semisolid transport medium and transported at ambient temperature for microbiological analysis at the Institute of Tropical Medicine in Antwerp, Belgium. The impact of the delay before microbiological analysis on primary culture of
Mycobacterium ulcerans
was investigated. The length of storage in semisolid transport medium varied from 6 days to 26 weeks. Of the 1,273 tissue fragments positive for
M. ulcerans
DNA by an IS
2404
-specific PCR, 576 (45.2%) yielded positive culture results. The sensitivity of direct smear examination was 64.6% (822/1,273 tissue fragments). The median time required to obtain a positive culture result was 11 weeks. Positive cultures were obtained even from samples kept for more than 2 months at ambient temperatures. Moreover, there was no reduction in the viability of
M. ulcerans
, as detected by culture, when specimens remained in semisolid transport medium for long periods of time (up to 26 weeks). We can conclude that the method with semisolid transport medium is very robust for clinical specimens from patients with Buruli ulcer that, due to circumstances, cannot be analyzed in a timely manner. This transport medium is thus very useful for the confirmation of a diagnosis of Buruli ulcer with specimens collected in the field.
Analysis of Toxigenic
Corynebacterium ulcerans
Strains Revealing Potential for False-Negative Real-Time PCR Results
Authors: Cassiday Pamela K. , Pawloski Lucia C. , Tiwari Tejpratap , Sanden Gary N. , Wilkins Patricia P. 
Published: November 2007

ABSTRACT

Diphtheria surveillance depends on the rapid and reliable recognition of the toxin gene in
Corynebacterium diphtheriae
. Real-time PCR is a rapid tool to confirm the presence of the diphtheria toxin gene (
tox
) in an isolate or specimen. We report that some toxigenic
Corynebacterium ulcerans
strains show atypical results in a real-time PCR for
tox
.
Shiga Toxin Gene-Containing
Escherichia coli
from Cattle and Diarrheic Children in the Pastoral Systems of Southwestern Uganda
Authors: Majalija Samuel , Segal Heidi , Ejobi Francis , Elisha B. Gay 
Published: November 2007

ABSTRACT

Shiga toxin-producing
Escherichia coli
(STEC) strains from cattle and diarrheic children in a pastoralist community in Uganda were investigated. The STEC strains belonged to a variety of different serogroups, and 70% of the strains were positive for the intimin gene,
eae
. STEC strains from two of the children were closely related to bovine strains.
Protease Activity, Self Interaction, and Small Interfering RNA Binding of the Silencing Suppressor P1b fromCucumber Vein Yellowing Ipomovirus
Authors: Valli Adrian , Dujovny Gabriela , García Juan Antonio 
Published: November 2007

ABSTRACTThe RNA silencing pathway mediated by small interfering RNAs (siRNAs) plays an important antiviral role in eukaryotes. To counteract this defense barrier, a large number of plant viruses express proteins with RNA silencing suppression activity. Recently, it was reported that the ipomovirusCucumber vein yellowing virus(CVYV), which lacks the typical silencing suppressor of members of the familyPotyviridae, i.e., HCPro, has a duplicated P1 coding sequence and that the downstream P1 copy, named P1b, has silencing suppression activity. In this study, we provide experimental evidence that P1b is a serine protease that self-cleaves at its C terminus but that its proteolytic activity is not essential for silencing suppression. In contrast, a putative zinc finger and a conserved basic motif in the N-terminal region of the protein are required for efficient silencing suppression. In vitro gel filtration-fast protein liquid chromatography and in vivo bimolecular fluorescence complementation assays showed that P1b binds itself to form oligomeric structures and that the zinc finger-like motif is essential for the self interaction. Moreover, we observed that CVYV P1b forms complexes with synthetic siRNAs, and this ability correlated with both silencing suppression activity and enhancement ofPotato virus Xpathogenicity in a mutational analysis. Together, these results suggest that CVYV P1b resembles potyviral HCPro and other viral proteins in interfering RNA silencing by preventing siRNA loading into the RNA-induced silencing complex.
JC Virus Agnoprotein Inhibits In Vitro Differentiation of Oligodendrocytes and Promotes Apoptosis
Authors: Merabova Nana , Kaniowska Dorota , Kaminski Rafal , Deshmane Satish L. , White Martyn K. , Amini Shohreh , Darbinyan Armine , Khalili Kamel 
Published: November 2007

ABSTRACTProductive infection of oligodendrocytes, which are responsible for the formation of myelin sheath in the central nervous system, with the human neurotropic virus JC virus (JCV) causes the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). In addition to encoding T antigen and the capsid proteins, which are produced at the early and late phases of the infection cycle, respectively, JCV encodes a small regulatory protein named agnoprotein that is important for successful completion of the virus life cycle. Here we used bipotential CG-4 cells to examine the impact of agnoprotein on oligodendrocyte differentiation and survival in the absence of JCV lytic infection. We demonstrate that the expression of agnoprotein delayed the formation of complex outgrowth networks of the cells during oligodendrocyte differentiation. These alterations were accompanied by high levels of DNA damage, induction of proapoptotic proteins, and suppression of prosurvival signaling. Accordingly, apoptosis was significantly increased upon the induction of CG-4 cells toward differentiation in cells expressing agnoprotein. These observations provide the first evidence for the possible involvement of agnoprotein, independent from its role in viral replication, in a series of biological events that may contribute to the pathological features seen in PML lesions.
Disease severity, self-reported experience of workplace discrimination and employment loss during the course of chronic HIV disease: differences according to gender and education
Authors: Dray-Spira R , Gueguen A , Lert F ,   the VESPA Study Group*
Published: November 2007

Objectives:Evidence for the existence of a harmful effect of chronic disease on employment status has been provided. Although this effect of chronic illness on employment has been reported to be higher among the groups with the lowest position on the labour market, the mechanisms of such inequalities are poorly understood. The present study aimed at investigating social inequalities in the chances of maintaining employment during the course of HIV infection and at examining the correlates of such inequalities.Methods:The authors used data from a national representative sample of people living with HIV in France (ANRS-EN12-VESPA survey). Retrospective information on social trajectory and disease characteristics from the time of HIV diagnosis was available. The risk of employment loss associated with indicators of disease severity and HIV-related workplace discrimination was computed over time since HIV diagnosis according to sociodemographic and occupational factors, using Cox proportional hazards models.Results:Among the 478 working-age participants diagnosed as being HIV-infected in the era of multitherapies and employed at the time of HIV diagnosis, 149 experienced employment loss. After adjusting for sociodemographic and occupational factors, disease severity and self-reported HIV-related discrimination at work were significantly associated with the risk of employment loss in a socially-differentiated manner: advancement in HIV disease was associated with an increased risk of employment loss among women (HR 4.45, 95% CI 2.10 to 9.43) but not among men; self-reported experience of HIV-related discrimination at work was associated with an increased risk of employment loss among individuals with a primary/secondary educational level (HR 8.85, 95% CI 3.68 to 21.30) but not among those more educated.Conclusions:Chronic HIV disease affects the chances of maintaining employment in a socially-differentiated manner, resulting in increasing inequalities regarding workforce participation. Disease severity and workplace HIV-related discrimination, particularly affecting the employment status of the most socioeconomically disadvantaged, may play a major role.
Prognostic Factors Related to Clinical Response in Patients with Metastatic Melanoma Treated by CTL-Associated Antigen-4 Blockade
Authors: Downey Stephanie G. , Klapper Jacob A. , Smith Franz O. , Yang James C. , Sherry Richard M. , Royal Richard E. , Kammula Udai S. , Hughes Marybeth S. , Allen Tamika E. , Levy Catherine L. , Yellin Michael , Nichol Geoffrey , White Donald E. , Steinberg Seth M. , Rosenberg Steven A. 
Published: November 2007

AbstractPurpose: CTL-associated antigen 4 (CTLA-4) can inhibit T-cell activation and helps maintain peripheral self-tolerance. Previously, we showed immune-related adverse events (IRAE) and objective, durable clinical responses in patients with metastatic melanoma treated with CTLA-4 blockade. We have now treated 139 patients in two trials and have sufficient follow-up to examine factors associated with clinical response.Experimental Design: A total of 139 patients with metastatic melanoma were treated: 54 patients received ipilimumab in conjunction with peptide vaccinations and 85 patients were treated with intra-patient dose escalation of ipilimumab and randomized to receive peptides in accordance with HLA-A*0201 status.Results: Three patients achieved complete responses (CR; ongoing at 29+, 52+, and 53+ months); an additional 20 patients achieved partial responses (PR) for an overall objective response rate of 17%. The majority of patients (62%, 86 of 139) developed some form of IRAE, which was associated with a greater probability of objective antitumor response (P = 0.0004); all patients with CR had more severe IRAEs. Prior therapy with IFNα-2b was a negative prognostic factor, whereas prior high-dose interleukin-2 did not significantly affect the probability of response. There were no significant differences in the rate of clinical response or development of IRAEs between the two trials. The duration of tumor response was not affected by the use of high-dose steroids for abrogation of treatment-related toxicities (P = 0.23). There were no treatment-related deaths.Conclusion: In patients with metastatic melanoma, ipilimumab can induce durable objective clinical responses, which are related to the induction of IRAEs.
Annexin XI Is Associated with Cisplatin Resistance and Related to Tumor Recurrence in Ovarian Cancer Patients
Authors: Song Jin , Shih Ie-ming , Salani Ritu , Chan Daniel W. , Zhang Zhen 
Published: November 2007

Abstract
Purpose: Ovarian cancer patients treated with cisplatin-based chemotherapy often develop acquired cisplatin resistance and, consequently, cancer recurrence. The precise nature of chemoresistance remains unclear. In this study, a protein identified to be associated with cisplatin resistance in ovarian cancer cells was investigated in ovarian cancer tissues to address its clinical significance.
Experimental Design: Antibody microarrays were used to identify proteins consistently differentially expressed across three pairs of cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines. Immunoblotting was used to confirm observed alteration of protein expression. The protein expression was further evaluated by immunohistochemical staining using tissue microarrays containing various human normal and malignant tissues and 164 surgical specimens derived from primary and recurrent ovarian cancer patients who underwent primary debulking surgery followed by standard chemotherapeutic regimen.
Results: Annexin XI was down-regulated in all three cisplatin-resistant cell lines as compared with their parent cells. Annexin XI expression was observed in the majority of human normal organs and decreased in some of the most common human malignancies. The expression level of Annexin XI in first recurrent ovarian cancers was much lower than that in primary ovarian cancers (P = 0.0004). Increased Annexin XI immunoreactivity in ovarian cancers seemed to prolong the disease-free interval of patients (P = 0.03). Annexin XI immunoreactivity inversely correlated with in vitro cisplatin resistance in ovarian cancers (P = 0.01).
Conclusion: Decreased expression of Annexin XI is characteristic for cisplatin-resistant cancer cells and may contribute to tumor recurrence. Annexin XI may be a potential marker for chemoresistance and earlier recurrence of ovarian cancer patients.
In vivoDiagnosis of Epidermal Growth Factor Receptor Expression using Molecular Imaging with a Cocktail of Optically Labeled Monoclonal Antibodies
Authors: Barrett Tristan , Koyama Yoshinori , Hama Yukihiro , Ravizzini Gregory , Shin In Soo , Jang Beom-Su , Paik Chang H. , Urano Yasuteru , Choyke Peter L. , Kobayashi Hisataka 
Published: November 2007

AbstractPurpose: Epidermal growth factor receptors (EGFR) play an important role in tumorigenesis and, therefore, have become targets for new molecular therapies. Here, we use a “cocktail” of optically labeled monoclonal antibodies directed against EGFR-1 (HER1) and EGFR-2 (HER2) to distinguish tumors by their cell surface expression profiles.Experimental Design: In vivo imaging experiments were done in tumor-bearing mice following s.c. injection of A431 (overexpressing HER1), NIH3T3/HER2+ (overexpressing HER2), and Balb3T3/DsRed (non-expression control) cell lines. After tumor establishment, a cocktail of optically labeled antibodies: Cy5.5-labeled cetuximab (anti-HER1) and Cy7-labeled trastuzumab (anti-HER2) was i.v. injected. In vivo and ex vivo fluorescence imaging was done. For comparison with radionuclide imaging, experiments were undertaken using 111Indium-labeled antibodies. Additionally, a “blinded” diagnostic study was done for mice bearing one tumor type.Results: In vivo spectral fluorescent molecular imaging of 14 mice with three tumor types clearly differentiated tumors using the cocktail of optically labeled antibodies both in vivo and ex vivo. Twenty-four hours after injection, A431 and NIH3T3/HER2+ tumors were detected distinctly by their peak on Cy5.5 and Cy7 spectral images, respectively; radionuclide imaging was unable to clearly distinguish tumors at this time point. In blinded single tumor experiments, investigators were able to correctly diagnose a total of 40 tumors.Conclusion: An in vivo imaging technique using an antibody cocktail simultaneously differentiated two tumors expressing distinct EGFRs and enabled an accurate characterization of each subtype.
Epigenetic Down-Regulation of ARF Expression Is a Selection Step in Immortalization of Human Fibroblasts by c-Myc
Authors: Benanti Jennifer A. , Wang Myra L. , Myers Hadley E. , Robinson Kristin L. , Grandori Carla , Galloway Denise A. 
Published: November 2007

Abstract
The transcription factor c-Myc is implicated in the pathogenesis of many cancers. Among the multiple functions of c-Myc, activation of hTert and other genes involved in cellular life span contributes to its role as an oncogene. However, the ability of c-Myc to directly immortalize human cells remains controversial. We show here that overexpression of c-Myc reproducibly immortalizes freshly isolated human foreskin fibroblasts. c-Myc–immortalized cells displayed no gross karyotypic abnormalities but consisted of an oligoclonal population, suggesting that additional events cooperated to achieve immortalization. Levels of p53 and p16 were increased, but both p53-dependent DNA damage response and growth arrest in response to p16 overexpression remained intact. A marked decrease in expression of the tumor suppressor ARF occurred in several independently established c-Myc–immortalized cell lines. Methylation-specific PCR showed that the ARF gene was methylated in immortalized but not early-passage c-Myc cells, whereas p16 was unmethylated in both cell populations. Restoration of ARF expression by treatment with a demethylating agent or overexpression by a retroviral vector coincided with inhibition of proliferation and senescence of c-Myc–immortalized cells. Our findings predict that epigenetic events play a significant role in human tumors that express high levels of c-Myc. (Mol Cancer Res 2007;5(11):1181–9)