bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation tagging of Arabidopsis POLYGALACTURONASE INVOLVED IN EXPANSION2 promotes hypocotyl elongation, leaf expansion, stem lignification, mechanical stiffening, and lodging
Authors: Xiao Chaowen , Barnes William J. , Zamil M. Shafayet , Yi Hojae , Puri Virendra M. , Anderson Charles T.
Published: December 2016

Pectin is the most abundant component of primary cell walls in eudicot plants. The modification and degradation of pectin affects multiple processes during plant development, including cell expansion, organ initiation, and cell separation. However, the extent to which pectin degradation by polygalacturonases affects stem development and secondary wall formation remains unclear. Using an activation tag screen, we identified a transgenic Arabidopsis thaliana line with longer etiolated hypocotyls, which overexpresses a gene encoding a polygalacturonase. We designated this gene as POLYGALACTURONASE INVOLVED IN EXPANSION2 (PGX2), and the corresponding activation tagged line as PGX2AT. PGX2 is widely expressed in young seedlings and in roots, stems, leaves, flowers, and siliques of adult plants. PGX2‐GFP localizes to the cell wall, and PGX2AT plants show higher total polygalacturonase activity and smaller pectin molecular masses than wild‐type controls, supporting a function for this protein in apoplastic pectin degradation. A heterologously expressed, truncated version of PGX2 also displays polygalacturonase activity in vitro. Like previously identified PGX1AT plants, PGX2AT plants have longer hypocotyls and larger rosette leaves, but they also uniquely display early flowering, earlier stem lignification, and lodging stems with enhanced mechanical stiffness that is possibly due to decreased stem thickness. Together, these results indicate that PGX2 both functions in cell expansion and influences secondary wall formation, providing a possible link between these two developmental processes.
The putative kinase substrate MUSE7 negatively impacts the accumulation of NLR proteins
Authors: Johnson Kaeli C. M. , Zhao Jin , Wu Zhongshou , Roth Charlotte , Lipka Volker , Wiermer Marcel , Li Xin
Published: December 2016

Stringent modulation of immune signaling in plants is necessary to enable a rapid response to pathogen attack without spurious defense activation. To identify genes involved in plant immunity, a forward genetic screen for enhancers of the autoimmune snc1 (suppressor of npr1, constitutive 1) mutant was conducted. The snc1 mutant contains a gain‐of‐function mutation in a gene encoding a NOD‐like receptor (NLR) protein. The isolated muse7 (mutant, snc1‐enhancing, 7) mutant was shown to confer a reversion to autoimmune phenotypes in the wild‐type‐like mos4 (modifier of snc1, 4) snc1 background. Positional cloning revealed that MUSE7 encodes an evolutionarily conserved putative kinase substrate of unknown function. The muse7 single mutants display enhanced resistance to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. While transcription of SNC1 is not enhanced, elevated SNC1 protein accumulation is associated with mutations in muse7. Accumulation of two additional NLR proteins, RPS2 (RESISTANCE TO PSEUDOMONAS SYRINGAE 2) and RPM1 (RESISTANCE TO PSEUDOMONAS SYRINGAE pv. MACULICOLA 1), was also observed in muse7 plants. Although proteasome‐mediated degradation of NLR proteins is a well studied event in plant immunity, no interactions were detected between MUSE7 and selected components of this pathway. This study has demonstrated a role for MUSE7 in modulating plant immune responses through negatively affecting NLR accumulation, and will benefit future studies of MUSE7 homologs in other species.
Repurposing Toremifene for Treatment of Oral Bacterial Infections
Authors: Gerits Evelien , Defraine Valerie , Vandamme Katleen , De Cremer Kaat , De Brucker Katrijn , Thevissen Karin , Cammue Bruno P. A. , Beullens Serge , Fauvart Maarten , Verstraeten Natalie , Michiels Jan
Published: December 2016

The spread of antibiotic resistance and the challenges associated with antiseptics such as chlorhexidine have necessitated a search for new antibacterial agents against oral bacterial pathogens. As a result of failing traditional approaches, drug repurposing has emerged as a novel paradigm to find new antibacterial agents. In this study, we examined the effects of the FDA-approved anticancer agent toremifene against the oral bacteria
Porphyromonas gingivalis
and
Streptococcus mutans
. We found that the drug was able to inhibit the growth of both pathogens, as well as prevent biofilm formation, at concentrations ranging from 12.5 to 25 μM. Moreover, toremifene was shown to eradicate preformed biofilms at concentrations ranging from 25 to 50 μM. In addition, we found that toremifene prevents
P. gingivalis
and
S. mutans
biofilm formation on titanium surfaces. A time-kill study indicated that toremifene is bactericidal against
S. mutans
. Macromolecular synthesis assays revealed that treatment with toremifene does not cause preferential inhibition of DNA, RNA, or protein synthesis pathways, indicating membrane-damaging activity. Biophysical studies using fluorescent probes and fluorescence microscopy further confirmed the membrane-damaging mode of action. Taken together, our results suggest that the anticancer agent toremifene is a suitable candidate for further investigation for the development of new treatment strategies for oral bacterial infections.
Various Sequence Types of Escherichia coli Isolates Coharboring
bla
NDM-5
and
mcr-1
Genes from a Commercial Swine Farm in China
Authors: Kong Ling-Han , Lei Chang-Wei , Ma Su-Zhen , Jiang Wei , Liu Bi-Hui , Wang Yong-Xiang , Guan Ru , Men Shuai , Yuan Qi-Wu , Cheng Guang-Yang , Zhou Wen-Cheng , Wang Hong-Ning
Published: December 2016

Sixteen different sequence types (STs) of
Escherichia coli
isolates from a commercial swine farm in China were confirmed to coharbor the carbapenem resistance gene
bla
NDM-5
and the colistin resistance gene
mcr-1
. Whole-genome sequencing revealed that
bla
NDM-5
and
mcr-1
were located on a 46-kb IncX3 plasmid and a 32-kb IncX4 plasmid, respectively. The two plasmids can transfer together with a low fitness cost, which might explain the presence of various STs of
E. coli
coharboring
bla
NDM-5
and
mcr-1
.
Mycobacterium tuberculosis Is Selectively Killed by Rifampin and Rifapentine in Hypoxia at Neutral pH
Authors: Iacobino Angelo , Piccaro Giovanni , Giannoni Federico , Mustazzolu Alessandro , Fattorini Lanfranco
Published: December 2016

The activities of rifampin, rifapentine, bedaquiline, PA-824, clofazimine, nitazoxanide, isoniazid, amikacin, moxifloxacin, niclosamide, thioridazine, and pyrazinamide were tested against nonreplicating (dormant)
Mycobacterium tuberculosis
H37Rv under conditions of hypoxia at pHs 5.8 and 7.3, mimicking environments of cellular granulomas and caseous granulomas, respectively. At pH 5.8, several drugs killed dormant bacilli, with the best being rifampin and rifapentine. At pH 7.3, only rifampin and rifapentine efficiently killed dormant bacilli, while all other drugs showed little activity.
Nephrotoxicity of Polymyxins: Is There Any Difference between Colistimethate and Polymyxin B?
Authors: Zavascki Alexandre P. , Nation Roger L.
Published: December 2016

Nephrotoxicity is a common adverse effect of the clinically used polymyxins, colistin and polymyxin B. This adverse effect is dose limiting for both polymyxins, as the plasma polymyxin concentrations associated with renal damage overlap those required for antibacterial effect. Since development of acute kidney injury (AKI) during therapy is highly undesirable, it is extremely important to know whether there is any difference between the nephrotoxic potential of colistin (administered as its inefficient prodrug, colistimethate) and polymyxin B (administered as the active form). Both polymyxins are cytotoxic to renal tubular cells and are prone to cause nephrotoxicity
in vivo
because of the renal handling mechanisms that facilitate accumulation of these compounds in these cells, processes that are reviewed in this article. Also reviewed are the emerging data that strongly suggest significantly higher rates of AKI in patients treated with colistimethate compared to patients treated with polymyxin B. This finding may be due to differences in pharmacokinetics and renal handling mechanisms of colistimethate and formed colistin versus polymyxin B, and consequently the relative amount of polymyxin material delivered to tubular cells. A lower risk of AKI with polymyxin B is one of several potential advantages over colistimethate. The relative safety and efficacy of the two agents require closer examination in well-designed clinical studies.
Pharmacological Blockade of the Chemokine Receptor CCR1 Protects Mice from Systemic Candidiasis of Hematogenous Origin
Authors: Lionakis Michail S. , Albert Nathaniel D. , Swamydas Muthulekha , Lee Chyi-Chia R. , Loetscher Pius , Kontoyiannis Dimitrios P.
Published: December 2016

Systemic candidiasis is a leading cause of nosocomial bloodstream infection with a high mortality rate despite treatment. Immune-based strategies are needed to improve outcomes. We previously reported that genetic deficiency in the chemokine receptor CCR1 improves survival and ameliorates tissue damage inCandida-infected mice. Here, we found that treatment of immunocompetentCandida-infected mice with the CCR1-selective antagonist BL5923 improves survival, decreases the kidney fungal burden, and protects from renal tissue injury.
Burkholderia humptydooensis sp. nov., a New Species Related to Burkholderia thailandensis and the Fifth Member of the Burkholderia pseudomallei Complex
Authors: Tuanyok Apichai , Mayo Mark , Scholz Holger , Hall Carina M. , Allender Christopher J. , Kaestli Mirjam , Ginther Jennifer , Spring-Pearson Senanu , Bollig Molly C. , Stone Joshua K. , Settles Erik W. , Busch Joseph D. , Sidak-Loftis Lindsay , Sahl Jason W. , Thomas Astrid , Kreutzer Lisa , Georgi Enrico , Gee Jay E. , Bowen Richard A. , Ladner Jason T. , Lovett Sean , Koroleva Galina , Palacios Gustavo , Wagner David M. , Currie Bart J. , Keim Paul
Published: December 2016

During routine screening for
Burkholderia pseudomallei
from water wells in northern Australia in areas where it is endemic, Gram-negative bacteria (strains MSMB43
T
, MSMB121, and MSMB122) with a similar morphology and biochemical pattern to
B. pseudomallei
and
B. thailandensis
were coisolated with
B. pseudomallei
on Ashdown's selective agar. To determine the exact taxonomic position of these strains and to distinguish them from
B. pseudomallei
and
B. thailandensis
, they were subjected to a series of phenotypic and molecular analyses. Biochemical and fatty acid methyl ester analysis was unable to distinguish
B. humptydooensis
sp. nov. from closely related species. With matrix-assisted laser desorption ionization–time of flight analysis, all isolates grouped together in a cluster separate from other
Burkholderia
spp. 16S rRNA and
recA
sequence analyses demonstrated phylogenetic placement for
B. humptydooensis
sp. nov. in a novel clade within the
B. pseudomallei
group. Multilocus sequence typing (MLST) analysis of the three isolates in comparison with MLST data from 3,340
B. pseudomallei
strains and related taxa revealed a new sequence type (ST318). Genome-to-genome distance calculations and the average nucleotide identity of all isolates to both
B. thailandensis
and
B. pseudomallei
, based on whole-genome sequences, also confirmed
B. humptydooensis
sp. nov. as a novel
Burkholderia
species within the
B. pseudomallei
complex. Molecular analyses clearly demonstrated that strains MSMB43
T
, MSMB121, and MSMB122 belong to a novel
Burkholderia
species for which the name
Burkholderia humptydooensis
sp. nov. is proposed, with the type strain MSMB43
T
(American Type Culture Collection BAA-2767; Belgian Co-ordinated Collections of Microorganisms LMG 29471; DDBJ accession numbers
CP013380
to
CP013382
).

IMPORTANCE
Burkholderia pseudomallei
is a soil-dwelling bacterium and the causative agent of melioidosis. The genus
Burkholderia
consists of a diverse group of species, with the closest relatives of
B. pseudomallei
referred to as the
B. pseudomallei
complex. A proposed novel species,
B. humptydooensis
sp. nov., was isolated from a bore water sample from the Northern Territory in Australia.
B. humptydooensis
sp. nov. is phylogenetically distinct from
B. pseudomallei
and other members of the
B. pseudomallei
complex, making it the fifth member of this important group of bacteria.
Genome Sequence of KP-Rio/2015, a Novel Klebsiella pneumoniae (
Podoviridae
) Phage
Authors: Meira Guilherme L. S. , Campos Fabricio S. , Albuquerque Julia P. , Cabral Maulori C. , Fracalanzza Sergio E. L. , Campos Renata M. , Vermelho Alane B. , Ferreira Davis F.
Published: December 2016

Klebsiella pneumoniae
is a pathogen frequently associated with antibiotic-resistant nosocomial infections. Here, we describe the genome of KP-Rio/2015, a novel phage of
K. pneumoniae
belonging to the family
Podoviridae
.
Draft Genome Sequence of Multitrait Plant Growth-Promoting
Bacillus
sp. Strain RZ2MS9
Authors: Batista Bruna Durante , Taniguti Lucas Mitsuo , Almeida Jaqueline Raquel , Azevedo João Lúcio , Quecine Maria Carolina
Published: December 2016

Bacillus
sp. strain RZ2MS9 is a multitrait soybean and maize growth-promoting bacterium isolated in Brazil from guarana's rhizosphere. Here, we present the draft genome sequence of RZ2MS9 and its genes involved in many features related to plant growth promotion.
Draft Genome Sequence of the Commensal Escherichia coli Strain F-18
Authors: Ormsby Michael J. , Johnson Síle A. , Wall Daniel M.
Published: December 2016

Here, we report the draft genome sequence of
Escherichia coli
strain F-18, originally isolated from the feces of a healthy individual in 1977. The draft genome is 5,246,829 bp, with a G+C content of 50.50%, and it encodes 4,933 predicted coding sequences (CDSs), 10 rRNAs, and 84 tRNAs.
Draft Genome Sequence of the Phosphate-Solubilizing Bacterium Pseudomonas argentinensis Strain SA190 Isolated from the Desert Plant
Indigofera argentea
Authors: Lafi Feras F. , Alam Intikhab , Geurts Rene , Bisseling Ton , Bajic Vladimir B. , Hirt Heribert , Saad Maged M.
Published: December 2016

Pseudomonas argentinensis
strain SA190 is a plant endophytic-inhabiting bacterium that was isolated from root nodules of the desert plant
Indigofera argentea
collected from the Jizan region of Saudi Arabia. Here, we report the genome sequence of SA190, highlighting several functional genes related to plant growth–promoting activity, environment adaption, and antifungal activity.
The Transcriptional Regulator CpsY Is Important for Innate Immune Evasion in Streptococcus pyogenes
Authors: Vega Luis A. , Valdes Kayla M. , Sundar Ganesh S. , Belew Ashton T. , Islam Emrul , Berge Jacob , Curry Patrick , Chen Steven , El-Sayed Najib M. , Le Breton Yoann , McIver Kevin S.
Published: December 2016

As an exclusively human pathogen,
Streptococcus pyogenes
(the group A streptococcus [GAS]) has specifically adapted to evade host innate immunity and survive in multiple tissue niches, including blood. GAS can overcome the metabolic constraints of the blood environment and expresses various immunomodulatory factors necessary for survival and immune cell resistance. Here we present our investigation of one such factor, the predicted LysR family transcriptional regulator CpsY. The encoding gene,
cpsY
, was initially identified as being required for GAS survival in a transposon-site hybridization (TraSH) screen in whole human blood. CpsY is homologous with transcriptional regulators of
Streptococcus mutans
(MetR),
Streptococcus iniae
(CpsY), and
Streptococcus agalactiae
(MtaR) that regulate methionine transport, amino acid metabolism, resistance to neutrophil-mediated killing, and survival
in vivo
. Our investigation indicated that CpsY is involved in GAS resistance to innate immune cells of its human host. However, GAS CpsY does not manifest the
in vitro
phenotypes of its homologs in other streptococcal species. GAS CpsY appears to regulate a small set of genes that is markedly different from the regulons of its homologs. The differential expression of these genes depends on the growth medium, and CpsY modestly influences their expression. The GAS CpsY regulon includes known virulence factors (
mntE
,
speB
,
spd
,
nga
[
spn
],
prtS
[
SpyCEP
], and
sse
) and cell surface-associated factors of GAS (
emm1
,
mur1.2
,
sibA
[
cdhA
], and
M5005_Spy0500
). Intriguingly, the loss of CpsY in GAS does not result in virulence defects in murine models of infection, suggesting that CpsY function in immune evasion is specific to the human host.
Differential Macrophage Polarization from Pneumocystis in Immunocompetent and Immunosuppressed Hosts: Potential Adjunctive Therapy during Pneumonia
Authors: Nandakumar Vijayalakshmi , Hebrink Deanne , Jenson Paige , Kottom Theodore , Limper Andrew H.
Published: December 2016

We explored differential polarization of macrophages during infection using a rat model ofPneumocystispneumonia. We observed enhanced pulmonary M1 macrophage polarization in immunosuppressed (IS) hosts, but an M2 predominant response in immunocompetent (IC) hosts followingPneumocystis cariniichallenge. Increased inflammation and inducible nitric oxide synthase (iNOS) levels characterized the M1 response. However, macrophage ability to produce nitric oxide was defective. In contrast, the lungs of IC animals revealed a prominent M2 gene signature, and these macrophages effectively elicited an oxidative burst associated with clearance ofPneumocystis. In addition, duringP. cariniiinfection the expression of Dectin-1, a critical receptor for recognition and clearance ofP. carinii, was upregulated in macrophages of IC animals but suppressed in IS animals. In the absence of an appropriate cytokine milieu for M2 differentiation,Pneumocystisinduced an M1 response bothin vitroandin vivo. The M1 response induced byP. cariniiwas plastic in nature and reversible with appropriate cytokine stimuli. Finally, we tested whether macrophage polarization can be modulatedin vivoand used to help manage the pathogenesis ofPneumocystispneumonia by adoptive transfer. Treatment with both M1 and M2 cells significantly improved survival ofP. carinii-infected IS hosts. However, M2 treatment provided the best outcomes with efficient clearance ofP. cariniiand reduced inflammation.
Anaplasma marginale Outer Membrane Protein A Is an Adhesin That Recognizes Sialylated and Fucosylated Glycans and Functionally Depends on an Essential Binding Domain
Authors: Hebert Kathryn S. , Seidman David , Oki Aminat T. , Izac Jerilyn , Emani Sarvani , Oliver Lee D. , Miller Daniel P. , Tegels Brittney K. , Kannagi Reiji , Marconi Richard T. , Carlyon Jason A.
Published: December 2016

Anaplasma marginalecauses bovine anaplasmosis, a debilitating and potentially fatal tick-borne infection of cattle. BecauseA. marginaleis an obligate intracellular organism, its adhesins that mediate entry into host cells are essential for survival. Here, we demonstrate thatA. marginaleouter membrane protein A (AmOmpA; AM854) contributes to the invasion of mammalian and tick host cells. AmOmpA exhibits predicted structural homology to OmpA ofA. phagocytophilum(ApOmpA), an adhesin that uses key lysine and glycine residues to interact with α2,3-sialylated and α1,3-fucosylated glycan receptors, including 6-sulfo-sialyl Lewis x (6-sulfo-sLex). Antisera against AmOmpA or its predicted binding domain inhibitsA. marginaleinfection of host cells. Residues G55 and K58 are contributory, and K59 is essential for recombinant AmOmpA to bind to host cells. Enzymatic removal of α2,3-sialic acid and α1,3-fucose residues from host cell surfaces makes them less supportive of AmOmpA binding. AmOmpA is both an adhesin and an invasin, as coating inert beads with it confers adhesiveness and invasiveness. Recombinant forms of AmOmpA and ApOmpA competitively antagonizeA. marginaleinfection of host cells, but a monoclonal antibody against 6-sulfo-sLexfails to inhibit AmOmpA adhesion andA. marginaleinfection. Thus, the two OmpA proteins bind related but structurally distinct receptors. This study provides a detailed understanding of AmOmpA function, identifies its essential residues that can be targeted by blocking antibody to reduce infection, and determines that it binds to one or more α2,3-sialylated and α1,3-fucosylated glycan receptors that are unique from those targeted by ApOmpA.
Legionella pneumophila OxyR Is a Redundant Transcriptional Regulator That Contributes to Expression Control of the Two-Component CpxRA System
Authors: Tanner Jennifer R. , Patel Palak G. , Hellinga Jacqueline R. , Donald Lynda J. , Jimenez Celine , LeBlanc Jason J. , Brassinga Ann Karen C.
Published: December 2016

Nominally an environmental organism,
Legionella pneumophila
is an intracellular parasite of protozoa but is also the causative agent of the pneumonia termed Legionnaires' disease, which results from inhalation of aerosolized bacteria by susceptible humans. Coordination of gene expression by a number of identified regulatory factors, including OxyR, assists
L. pneumophila
in adapting to the stresses of changing environments.
L. pneumophila
OxyR (OxyR
Lp
) is an ortholog of
Escherichia coli
OxyR; however, OxyR
Lp
was shown elsewhere to be functionally divergent, such that it acts as a transcription regulator independently of the oxidative stress response. In this study, the use of improved gene deletion methods has enabled us to generate an unmarked in-frame deletion of
oxyR
in
L. pneumophila
. Lack of OxyR
Lp
did not affect
in vitro
growth or intracellular growth in
Acanthamoeba castellanii
protozoa and U937-derived macrophages. The expression of OxyR
Lp
does not appear to be regulated by CpxR, even though purified recombinant CpxR bound a DNA sequence similar to that reported for CpxR elsewhere. Surprisingly, a lack of OxyR
Lp
resulted in elevated activity of the promoters located upstream of
icmR
and the
lpg1441-cpxA
operon, and OxyR
Lp
directly bound to these promoter regions, suggesting that OxyR
Lp
is a direct repressor. Interestingly, a strain overexpressing OxyR
Lp
demonstrated reduced intracellular growth in
A. castellanii
but not in U937-derived macrophages, suggesting that balanced expression control of the two-component CpxRA system is necessary for survival in protozoa. Taken together, this study suggests that OxyR
Lp
is a functionally redundant transcriptional regulator in
L. pneumophila
under the conditions evaluated herein.

IMPORTANCE
Legionella pneumophila
is an environmental pathogen, with its transmission to the human host dependent upon its ability to replicate in protozoa and survive within its aquatic niche. Understanding the genetic factors that contribute to
L. pneumophila
survival within each of these unique environments will be key to limiting future point-source outbreaks of Legionnaires' disease. The transcriptional regulator
L. pneumophila
OxyR (OxyR
Lp
) has been previously identified as a potential regulator of virulence traits warranting further investigation. This study demonstrated that
oxyR
is nonessential for
L. pneumophila
survival
in vitro
and
in vivo
via mutational analysis. While the mechanisms of how OxyR
Lp
expression is regulated remain elusive, this study shows that OxyR
Lp
negatively regulates the expression of the
cpxRA
two-component system necessary for intracellular survival in protozoa.
25-Hydroxycholesterol Inhibition of Lassa Virus Infection through Aberrant GP1 Glycosylation
Authors: Shrivastava-Ranjan Punya , Bergeron Éric , Chakrabarti Ayan K. , Albariño César G. , Flint Mike , Nichol Stuart T. , Spiropoulou Christina F.
Published: December 2016

Lassa virus (LASV) infection is a major public health concern due to high fatality rates and limited effective treatment. The interferon-stimulated gene
cholesterol 25-hydroxylase
(
CH25H
) encodes an enzyme that catalyzes the production of 25-hydroxycholesterol (25HC). 25HC is involved in regulating cholesterol biosynthesis and has recently been identified as a potent antiviral targeting enveloped virus entry. Here, we show a previously unrecognized role of CH25H in inhibiting LASV glycoprotein glycosylation and the production of infectious virus. Overexpression of CH25H or treatment with 25HC decreased LASV G1 glycoprotein
N
-glycan maturation and reduced the production of infectious LASV. Depletion of endogenous CH25H using small interfering RNA (siRNA) enhanced the levels of fully glycosylated G1 and increased infectious LASV production. Finally, LASV particles produced from 25HC-treated cells were found to be less infectious, to incorporate aberrantly glycosylated GP1 species, and to be defective in binding alpha-dystroglycan, an attachment and entry receptor. Our findings identify a novel role for CH25H in controlling LASV propagation and indicate that manipulation of the expression of CH25H or the administration of 25HC may be a useful anti-LASV therapy.

IMPORTANCE
Lassa fever is an acute viral hemorrhagic fever in humans caused by Lassa virus (LASV). No vaccine for LASV is currently available. Treatment is limited to the administration of ribavirin, which is only effective when given early in the course of illness.
Cholesterol 25-hydroxylase
(
CH25H
) is a recently identified interferon-stimulated gene (ISG); it encodes an enzyme that catalyzes the production of 25-hydroxycholesterol (25HC), which inhibits several viruses. Here, we identify a novel antiviral mechanism of 25HC that is dependent on inhibiting the glycosylation of Lassa virus (LASV) glycoprotein and reducing the infectivity of LASV as a means of suppressing viral replication. Since N-linked glycosylation is a critical feature of other enveloped-virus glycoproteins, 25HC may be a broad inhibitor of virus infectivity.
Complete Microbiota Engraftment Is Not Essential for Recovery from Recurrent Clostridium difficile Infection following Fecal Microbiota Transplantation
Authors: Staley Christopher , Kelly Colleen R. , Brandt Lawrence J. , Khoruts Alexander , Sadowsky Michael J.
Published: December 2016

Bacterial communities from subjects treated for recurrent
Clostridium difficile
infection (rCDI) by fecal microbiota transplantation (FMT), using either heterologous donor stool samples or autologous stool samples, were characterized by Illumina next-generation sequencing. As previously reported, the success of heterologous FMT (90%) was superior to that of autologous FMT (43%) (
P
= 0.019), and post-FMT intestinal bacterial communities differed significantly between treatment arms (
P
< 0.001). Subjects cured by autologous FMT typically had greater abundances of the
Clostridium
XIVa clade and
Holdemania
bacteria prior to treatment, and the relative abundances of these groups increased significantly after FMT compared to heterologous FMT and pre-FMT samples. The typical shift to post-FMT, donor-like assemblages, featuring high relative abundances of genera within the
Bacteroidetes
and
Firmicutes
phyla, was not observed in the autologous FMT subjects. Autologous FMT patient bacterial communities were significantly different in composition than those for heterologous FMT patients and donors (
P
< 0.001). The SourceTracker program, which employs a Bayesian algorithm to determine source contributions to sink communities, showed that patients initially treated by heterologous FMT had significantly higher percentages of engraftment (i.e., similarity to donor communities, mean value of 74%) compared to those who suffered recurrence following autologous FMT (1%) (
P
≤ 0.013). The findings of this study suggest that complete donor engraftment may be not necessary if functionally critical taxa are present in subjects following antibiotic therapy.

IMPORTANCE
This study provides a detailed characterization of fecal bacterial communities in subjects who participated in a previously published randomized clinical trial to treat recurrent
C. difficile
infection (rCDI). Bacterial communities were characterized to determine differences between subjects who received fecal bacteria either from healthy donor stool samples or their own stool samples as “placebo” in order to determine which groups of bacteria were most important in achieving a cure. The results of this study suggested that bacteria associated with secondary bile acid metabolism could potentially provide resistance to infection and that complete transfer of healthy donor microorganisms was not necessary to resolve CDI following unsuccessful antibiotic treatment.
Single-Cell Analysis of the Plasmablast Response to Vibrio cholerae Demonstrates Expansion of Cross-Reactive Memory B Cells
Authors: Kauffman Robert C. , Bhuiyan Taufiqur R. , Nakajima Rie , Mayo-Smith Leslie M. , Rashu Rasheduzzaman , Hoq Mohammad Rubel , Chowdhury Fahima , Khan Ashraful Islam , Rahman Atiqur , Bhaumik Siddhartha K. , Harris Levelle , O'Neal Justin T. , Trost Jessica F. , Alam Nur Haq , Jasinskas Algis , Dotsey Emmanuel , Kelly Meagan , Charles Richelle C. , Xu Peng , Kováč Pavol , Calderwood Stephen B. , Ryan Edward T. , Felgner Phillip L. , Qadri Firdausi , Wrammert Jens , Harris Jason B.
Published: December 2016

We characterized the acute B cell response in adults with cholera by analyzing the repertoire, specificity, and functional characteristics of 138 monoclonal antibodies (MAbs) generated from single-cell-sorted plasmablasts. We found that the cholera-induced responses were characterized by high levels of somatic hypermutation and large clonal expansions. A majority of the expansions targeted cholera toxin (CT) or lipopolysaccharide (LPS). Using a novel proteomics approach, we were able to identify sialidase as another major antigen targeted by the antibody response toVibrio choleraeinfection. Antitoxin MAbs targeted both the A and B subunits, and most were also potent neutralizers of enterotoxigenicEscherichia coliheat-labile toxin. LPS-specific MAbs uniformly targeted the O-specific polysaccharide, with no detectable responses to either the core or the lipid moiety of LPS. Interestingly, the LPS-specific antibodies varied widely in serotype specificity and functional characteristics. One participant infected with the Ogawa serotype produced highly mutated LPS-specific antibodies that preferentially bound the previously circulating Inaba serotype. This demonstrates durable memory against a polysaccharide antigen presented at the mucosal surface and provides a mechanism for the long-term, partial heterotypic immunity seen following cholera.

IMPORTANCECholera is a diarrheal disease that results in significant mortality. While oral cholera vaccines are beneficial, they do not achieve equivalent protection compared to infection withVibrio cholerae. Although antibodies likely mediate protection, the mechanisms of immunity following cholera are poorly understood, and a detailed understanding of antibody responses to cholera is of significance for human health. In this study, we characterized the human response to cholera at the single-plasmablast, monoclonal antibody level. Although this approach has not been widely applied to the study of human bacterial infection, we were able to uncover the basis of cross-reactivity between differentV. choleraeserotypes and the likely impact of prior enterotoxigenicEscherichia coliexposure on the response to cholera, as well as identify novel antigenic targets. In addition to improving our understanding of the repertoire and function of the antibody response to cholera in humans, this study has implications for future cholera vaccination efforts.
The Cytolethal Distending Toxin Produced by Nontyphoidal
Salmonella
Serotypes Javiana, Montevideo, Oranienburg, and Mississippi Induces DNA Damage in a Manner Similar to That of Serotype Typhi
Authors: Miller Rachel A. , Wiedmann Martin
Published: December 2016

Select nontyphoidal
Salmonella enterica
(NTS) serotypes were recently found to encode the
Salmonella
cytolethal distending toxin (S-CDT), an important virulence factor for serotype Typhi, the causative agent of typhoid fever. Using a PCR-based assay, we determined that among 21 NTS serotypes causing the majority of food-borne salmonellosis cases in the United States, genes encoding S-CDT are conserved in isolates representing serotypes Javiana, Montevideo, and Oranienburg but that among serotype Mississippi isolates, the presence of S-CDT-encoding genes is clade associated. HeLa cells infected with representative strains of these S-CDT-positive serotypes had a significantly higher proportion of cells arrested in the G
2
/M phase than HeLa cells infected with representative strains of S-CDT-negative serotypes Typhimurium, Newport, and Enteritidis. The G
2
/M cell cycle arrest was dependent on CdtB, the active subunit of S-CDT, as infection with isogenic Δ
cdtB
mutants abolished their ability to induce a G
2
/M cell cycle arrest. Infection with S-CDT-encoding serotypes was significantly associated with activation of the host cell’s DNA damage response (DDR), a signaling cascade that is important for detecting and repairing damaged DNA. HeLa cell populations infected with S-CDT-positive serotypes had a significantly higher proportion of cells with DDR protein 53BP1 and γH2AX foci than cells infected with either S-CDT-negative serotypes or isogenic Δ
cdtB
strains. Intoxication with S-CDT occurred via autocrine and paracrine pathways, as uninfected HeLa cells among populations of infected cells also had an activated DDR. Overall, we show that S-CDT plays a significant role in the cellular outcome of infection with NTS serotypes.

IMPORTANCE
The recent discovery that multiple serotypes encode S-CDT, which was previously established as an important virulence factor for serotype Typhi, suggested that this toxin may also contribute to the outcome of infection with nontyphoidal serotypes. In this study, we demonstrate that at a cellular level, S-CDT significantly alters the outcome of infection by inducing DNA damage which is associated with a cell cycle arrest and activation of the host cell’s DDR. Importantly, these results contribute valuable information for assessing the public health implications of S-CDT in infections with NTS serotypes. Our data suggest that infection with
Salmonella
strains that encode S-CDT has the potential to result in DNA damage, which may contribute to long-term sequelae.
Hematologic Complications of Tuberculosis
Authors: Balepur Shyam S. , Schlossberg David
Published: December 2016

Tuberculosis (TB) affects the production and life span of all hematologic cellular components. In addition, plasma coagulation factors may be affected, resulting in sometimes life-threatening complications. Iron, folate, and vitamin B12metabolism is derailed. The pharmacological agents used for TB therapy may also cause hematologic changes. There are some uncommon manifestations of TB in nontuberculous hematologic patients. There have been some exciting developments in the field of imaging to screen for TB, TB pathophysiology at the cellular level, and our understanding of immune response in TB. Advances have been made in pharmacologic therapeutic options, including discovery of new drugs in the fight against drug-resistant TB, bearing in mind their hematologic effects. This chapter reviews and updates known hematologic effects of TB and its therapy and some lesser known effects of TB in patients with nontuberculous hematologic conditions.
Impact of zinc and zinc oxide nanoparticles on the physiological and biochemical processes in tomato and wheat
Authors: Amooaghaie Rayhaneh , Norouzi Maryam , Saeri Mohammad
Published: December 2016

In this study, the effects of various concentrations of zinc and zinc oxide nanoparticles (nZn, nZnO) were evaluated in tomato and wheat. Results showed that at lower concentrations, nZn and nZnO augmented seed germination and growth parameters, whereas with higher concentrations, the nanoparticles reduced these traits. Zn concentrations corresponding to Zn dissolved (3–23 mg Zn·L−1) from nanoparticles (NPs) did not significantly affect the germination indices in either species. Compared with the bulk counterparts of ZnO, NPs exerted more toxicity on seed germination, growth parameters, and chlorophyll and carotenoid contents, and also increased Zn bioaccumulation more. More often than not, nZnO provoked more adverse symptoms than nZn at equivalent concentrations. In both species, the Zn accumulation in roots and shoots followed the order: Zn2+ ions > nZn > nZnO > bulk ZnO > control. Exposure to 200 mg Zn·L−1 nZn and nZnO increased H2O2 accumulation and malondealdehyde (MDA) levels, which were more pronounced in tomato than wheat. The results suggested that the toxicity of NPs could be due to the particle itself, or from the Zn2+ ions dissolved from NPs. Moreover, nanotoxicity, like other stresses, caused oxidative stress in both plants, and the differences in proline accumulation and the antioxidant enzyme activities of leaves, especially APX activity, at least in part, explained the higher sensitivity of tomato to NPs than wheat.
Fire and dwarf mistletoe (Viscaceae: Arceuthobium species) in western North America: contrasting Arceuthobium tsugense and Arceuthobium americanum
Authors: Shaw David C. , Agne Michelle C.
Published: December 2016

Dwarf mistletoes (Viscaceae: Arceuthobium spp.) and fire interact in important ways in the coniferous forests of western North America. Fire directly affects dwarf mistletoes by killing the host, host branch, or heating/smoking the aerial shoots and fruits. Fire is a primary determinant of dwarf mistletoe distribution on the landscape, and time since fire controls many aspects of dwarf mistletoe epidemiology. Conversely, dwarf mistletoes can influence fire by causing changes in forest composition, structure, and fuels. Prescribed fire is important for management of dwarf mistletoes, while fire suppression is thought to have increased dwarf mistletoe abundance in western forests. Two dwarf mistletoes are compared in order to illustrate fire interactions in Oregon and Washington, USA: Arceuthobium americanum Nutt. ex Engelm. (lodgepole pine dwarf mistletoe) and Arceuthobium tsugense (Rosendahl)(western hemlock dwarf mistletoe). Arceuthobium persists on the landscape where the host is not killed by fire. Arceuthobium americanum spreads directly into the regenerating Pinus contorta Dougl. ex Loud., while A. tsugense persists in refugia for 200 years or more following fire. Host successional status is a driver of fire – dwarf mistletoe interactions, but forest disturbance agents also play a role. Given the importance of these interactions to the ecology of fire-prone forests, dwarf mistletoes warrant inclusion in disturbance ecology research.
Utilization of carbon sources by clinical isolates ofAeromonas
Authors: Prediger Karoline C. , Surek Monica , Dallagassa Cibelle B. , Assis Flávia E.A. , Piantavini Mario S. , Souza Emanuel M. , Pedrosa Fábio O. , Farah Sônia M.S.S. , Alberton Dayane , Fadel-Picheth Cyntia M.T.
Published: December 2016

Bacteria in the genus Aeromonas are primarily aquatic organisms; however, some species can cause diseases in humans, ranging from wound infections to septicemia, of which diarrhea is the most common condition. The ability to use a variety of carbon substrates is advantageous for pathogenic bacteria. Therefore, we used Biolog GN2 microplates to analyze the ability of 103 clinical, predominantly diarrheal, isolates of Aeromonas to use various carbon sources, and we verified whether, among the substrates metabolized by these strains, there were some endogenous to the human intestine. The results indicate that Aeromonas present great diversity in the utilization of carbon sources, and that they preferentially use carbohydrates and amino acids as carbon sources. Among the carbon sources metabolized by Aeromonas in vitro, some were found to be components of intestinal mucin, including aspartic acid, glutamic acid, l-serine, galactose, N-acetyl-glucosamine, and glucose, which were used by all strains tested. Additionally, mannose, d-serine, proline, threonine, and N-acetyl-galactosamine were used by several strains. The potential to metabolize substrates endogenous to the intestine may contribute to Aeromonas’ capacity to grow in and colonize the intestine. We speculate that this may help explain the ability of Aeromonas to cause diarrhea.
Biocontrol of Burkholderia cepacia complex bacteria and bacterial phytopathogens by Bdellovibrio bacteriovorus
Authors: McNeely Damian , Chanyi Ryan M. , Dooley James S. , Moore John E. , Koval Susan F.
Published: December 2016

Bdellovibrio and like organisms are predatory bacteria that have the unusual property of using the cytoplasmic constituents of other Gram-negative bacteria as nutrients. These predators may thus provide an alternative approach to the biocontrol of human and plant pathogens. Predators were isolated on Burkholderia cenocepacia K56-2 and J2315 as prey cells, in enrichment cultures with soil and sewage. Three isolates (DM7C, DM8A, and DM11A) were identified as Bdellovibrio bacteriovorus on the basis of morphology, a periplasmic life cycle, and 16S rRNA gene sequencing. The prey range of these isolates was tested on Burkholderia cepacia complex bacteria and several phytopathogenic bacteria of agricultural importance. Of 31 strains of the Burkholderia cepacia complex tested, only 4 were resistant to predation by strain DM7C. A subset of 9 of the prey tested were also susceptible to strains DM8A and DM11A. Of 12 phytopathogens tested, 4 were resistant to strains DM7C and DM8A, and only 2 were resistant to strain DM11A. Thus, Bdellovibrio bacteriovorus strains retrieved from environmental samples on 2 Burkholderia cenocepacia isolates from cystic fibrosis patients did not distinguish in their prey range between other isolates of that pathogen or phytopathogens. Such strains hold promise as potential wide-spectrum biocontrol agents.
Protective mechanisms of melatonin against hydrogen-peroxide-induced toxicity in human bone-marrow-derived mesenchymal stem cells
Authors: Mehrzadi Saeed , Safa Majid , Kamrava Seyed Kamran , Darabi Radbod , Hayat Parisa , Motevalian Manijeh
Published: December 2016

Many obstacles compromise the efficacy of bone marrow mesenchymal stem cells (BM-MSCs) by inducing apoptosis in the grafted BM-MSCs. The current study investigates the effect of melatonin on important mediators involved in survival of BM-MSCs in hydrogen peroxide (H2O2) apoptosis model. In brief, BM-MSCs were isolated, treated with melatonin, and then exposed to H2O2. Their viability was assessed by MTT assay and apoptotic fractions were evaluated through Annexin V, Hoechst staining, and ADP/ATP ratio. Oxidative stress biomarkers including ROS, total antioxidant power (TAP), superoxide dismutase (SOD) and catalase (CAT) activity, glutathione (GSH), thiol molecules, and lipid peroxidation (LPO) levels were determined. Secretion of inflammatory cytokines (TNF-α and IL-6) were measured by ELISA assay. The protein expression of caspase-3, Bax, and Bcl-2, was also evaluated by Western blotting. Melatonin pretreatment significantly increased viability and decreased apoptotic fraction of H2O2-exposed BM-MSCs. Melatonin also decreased ROS generation, as well as increasing the activity of SOD and CAT enzymes and GSH content. Secretion of inflammatory cytokines in H2O2-exposed cells was also reduced by melatonin. Expression of caspase-3 and Bax proteins in H2O2-exposed cells was diminished by melatonin pretreatment. The findings suggest that melatonin may be an effective protective agent against H2O2-induced oxidative stress and apoptosis in MSC.
The effect of midkine on growth factors and oxidative status in an experimental wound model in diabetic and healthy rats
Authors: Dik Burak , Baş Ahmet Levent , Yazıhan Nuray
Published: December 2016

Wound healing is important for longevity. Midkine is a cytokine involved in controlling tissue repair and new tissue development, and in regulating inflammation. We investigated the effect of midkine on wound healing in rats. In total, 108 Wistar albino rats were used: 12 as healthy and diabetic controls; 96 were split into 4 groups: healthy, saline treated; healthy, midkine (10 ng/kg, 48 h intervals) treated; diabetic, saline treated; and diabetic, midkine treated. Following wound creation, 6 rats per group were euthanized on days 3, 7, 14, and 28; the wounded skin was removed. Levels of epidermal growth factor (EGF), matrix metalloproteinase-8 (MMP-8), transforming growth factor beta (TGF-β), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and thiobarbituric acid reactive substances (TBARS) were measured. MMP-8 and PDGF levels fluctuated in all groups; TGF-β fluctuated in the diabetic groups and was significantly higher in the HM group than other groups after 14 days. EGF and VEGF levels were increased in the HM group after 3 days. TBARS levels were highest in the diabetic groups. Macroscopically, the midkine-treated groups healed better. Midkine can accelerate wound healing by influencing growth factors and oxidative status in wound tissues.
Reversal of P-glycoprotein-mediated multidrug resistance and pharmacokinetics study in rats by WYX-5
Authors: Wang Yuzhu , Cui Jian , Dai Yuxuan , Wu Yuxiang , Huang Wenlong , Qian Hai , Ge Liang
Published: December 2016

Multidrug resistance (MDR) is one of the major obstacles confronted in cancer chemotherapy; this obstacle is mainly due to the overexpression of P-glycoprotein (P-gp). Co-administration of anticancer drugs and P-gp inhibitors is a promising approach to overcome MDR. WYX-5, a novel P-gp inhibitor, shows a notable reversal effect with low cytotoxicity in vitro. In this paper, the reversal mechanism and safety of the MDR modulator WYX-5 were explored in vitro, and evaluated for its pharmacokinetics and effects on adriamycin (ADM) metabolism in vivo. The results suggest that WYX-5 is a potent P-gp inhibitor with EC50 in nanomole range (EC50 = 204.3 ± 20.2 nmol·L−1), relative safety (therapeutic index = 446.4), which performs as a substrate of P-gp and retrains its function. Further, WYX-5 (5 mg·kg−1) had relatively ideal pharmacokinetic properties (T1/2 = 6.448 h, F = 96.05%) without interactions with ADM metabolism in vivo. In conclusion, WYX-5 may be a promising candidate for MDR cancer combined-chemotherapy research.
Cascading community and ecosystem consequences of introduced coconut palms (Cocos nucifera) in tropical islands
Authors: Young H.S. , Miller-ter Kuile A. , McCauley D.J. , Dirzo R.
Published: December 2016

Biological invasions are a pervasive and dominant form of anthropogenic disturbance. However, we seldom have the opportunity to evaluate the long-term, indirect, and often slow-moving cascading effects of invasions at the community and ecosystem scale. Here we synthesize the collective knowledge from 10 years of study on the influence of the deep historical introduction of coconut palms (Cocos nucifera L.) across a series of islets at Palmyra Atoll. Through a suite of pathways, we find this palm drives near-complete ecosystem state change when it becomes dominant. Abiotic conditions are transformed, with major soil nutrients 2.7–11.5 times lower and water stress 15% elevated in palm-dominated forests compared with native forest. Faunal communities are likewise dramatically altered, not only in composition but also in behavior, body size, and body condition. Biotic interactions, including herbivory rates, palatability, and seed predation, are likewise changed. Cumulatively, these changes transform food webs, leading to dramatically shortened and simplified food chains in invaded ecosystems. Many of these changes appear to create slow-acting feedback loops that favor the palm at the expense of native species. Given the widespread nature of this historical introduction, many island and coastal regions of tropical oceans may be similarly transformed.