bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acute partial sleep restriction does not impact arterial function in young and healthy humans
Authors: Cherubini Joshua M. , Cheng Jem L. , Armstrong Calvin M. , Kamal Michael J. , Parise Gianni , MacDonald Maureen J. 
Published: June 2024

AbstractHabitual short sleep durations are associated with several cardiovascular diseases. Experimental research generally supports these findings as metrics of arterial function are impaired after complete deprivation of sleep and after longer periods of partial sleep restriction. The acute influence of a single instance of partial sleep restriction (PSR), however, has not been defined. We evaluated arterial structure and function among 32 university‐aged participants on two occasions: once after normal habitual sleep (NS), and again the morning after an acute partial sleep restriction (PSR) intervention involving only 3 h of sleep for a single night. Endothelial function was measured using ultrasonography at the brachial artery via flow‐mediated dilatation (FMD), and a ramp peak oxygen uptake test was used to evaluate cardiorespiratory fitness. Blood samples were collected from a subset of participants to investigate the influence of circulatory factors on cellular mechanisms implicated in endothelial function. Sleep duration was lower after a night of PSR compared to NS (P < 0.001); however, there were no appreciable differences in any haemodynamic outcome between conditions. FMD was not different between NS and PSR (NS: 6.5 ± 2.9%; PSR: 6.3 ± 2.9%; P = 0.668), and cardiorespiratory fitness did not moderate the haemodynamic response to PSR (all P > 0.05). Ex vivo cell culture results aligned with in vivo data, showing that acute PSR does not alter intracellular processes involved in endothelial function. No differences in arterial structure or function were observed between NS and acute PSR in healthy and young participants, and cardiorespiratory fitness does not modulate the arterial response to acute sleep restriction.
Two Zn
2
Cys
6
-type transcription factors respond to aromatic compounds and regulate the expression of laccases in the white-rot fungus
Trametes hirsuta
Authors: Wang Chenkai , Zhang Xinlei , Wu Kun , Liu Shenglong , Li Xiang , Zhu Chaona , Xiao Yazhong , Fang Zemin , Liu Juanjuan 
Published: June 2024

ABSTRACT

White-rot fungi differentially express laccases when they encounter aromatic compounds. However, the underlying mechanisms are still being explored. Here, proteomics analysis revealed that in addition to increased laccase activity, proteins involved in sphingolipid metabolism and toluene degradation as well as some cytochrome P450s (CYP450s) were differentially expressed and significantly enriched during 48 h of
o
-toluidine exposure, in
Trametes hirsuta
AH28-2. Two Zn
2
Cys
6
-type transcription factors (TFs), TH8421 and TH4300, were upregulated. Bioinformatics docking and isothermal titration calorimetry assays showed that each of them could bind directly to
o
-toluidine and another aromatic monomer, guaiacol. Binding to aromatic compounds promoted the formation of TH8421/TH4300 heterodimers.
TH8421
and
TH4300
silencing in
T. hirsuta
AH28-2 led to decreased transcriptional levels and activities of LacA and LacB upon
o
-toluidine and guaiacol exposure. EMSA and ChIP-qPCR analysis further showed that TH8421 and TH4300 bound directly with the promoter regions of
lacA
and
lacB
containing CGG or CCG motifs. Furthermore, the two TFs were involved in direct and positive regulation of the transcription of some CYP450s. Together, TH8421 and TH4300, two key regulators found in
T. hirsuta
AH28-2, function as heterodimers to simultaneously trigger the expression of downstream laccases and intracellular enzymes. Monomeric aromatic compounds act as ligands to promote heterodimer formation and enhance the transcriptional activities of the two TFs.

IMPORTANCE

White-rot fungi differentially express laccase isoenzymes when exposed to aromatic compounds. Clarification of the molecular mechanisms underlying differential laccase expression is essential to elucidate how white-rot fungi respond to the environment. Our study shows that two Zn
2
Cys
6
-type transcription factors form heterodimers, interact with the promoters of laccase genes, and positively regulate laccase transcription in
Trametes hirsuta
AH28-2. Aromatic monomer addition induces faster heterodimer formation and rate of activity. These findings not only identify two new transcription factors involved in fungal laccase transcription but also deepen our understanding of the mechanisms underlying the response to aromatics exposure in white-rot fungi.
Comparative reservoir competence of
Peromyscus leucopus
, C57BL/6J, and C3H/HeN for
Borrelia burgdorferi
B31
Authors: Bourgeois Jeffrey S. , You Stephanie S. , Clendenen Luke H. , Shrestha Muskan , Petnicki-Ocwieja Tanja , Telford Sam R. , Hu Linden T. 
Published: June 2024

ABSTRACT

Borrelia burgdorferi
, a Lyme disease spirochete, causes a range of acute and chronic maladies in humans. However, a primary vertebrate reservoir in the United States, the white-footed deermouse
Peromyscus leucopus
, is reported not to have reduced fitness following infection. Although laboratory strains of
Mus musculus
mice have successfully been leveraged to model acute human Lyme disease, the ability of these rodents to model
B. burgdorferi-P. leucopus
interactions remains understudied. Here, we compared infection of
P. leucopus
with
B. burgdorferi
B31 with infection of the traditional
B. burgdorferi
murine models—C57BL/6J and C3H/HeN
Mus musculus
, which develop signs of inflammation akin to human disease. We find that
B. burgdorferi
was able to reach much higher burdens (10- to 30-times higher) in multiple
M. musculus
skin sites and that the overall dynamics of infection differed between the two rodent species. We also found that
P. leucopus
remained transmissive to larval
Ixodes scapularis
for a far shorter period than either
M. musculus
strain. In line with these observations, we found that
P. leucopus
does launch a modest but sustained inflammatory response against
B. burgdorferi
in the skin, which we hypothesize leads to reduced bacterial viability and rodent-to-tick transmission in these hosts. Similarly, we also observe evidence of inflammation in infected
P. leucopus
hearts. These observations provide new insight into reservoir species and the
B. burgdorferi
enzootic cycle.

IMPORTANCE

A Lyme disease-causing bacteria,
Borrelia burgdorferi
, must alternate between infecting a vertebrate host—usually rodents or birds—and ticks. In order to be successful in that endeavor, the bacteria must avoid being killed by the vertebrate host before it can infect a new larval tick. In this work, we examine how
B. burgdorferi
and one of its primary vertebrate reservoirs,
Peromyscus leucopus
, interact during an experimental infection. We find that
B. burgdorferi
appears to colonize its natural host less successfully than conventional laboratory mouse models, which aligns with a sustained seemingly anti-bacterial response by
P. leucopus
against the microbe. These data enhance our understanding of
P. leucopus
host-pathogen interactions and could potentially serve as a foundation to uncover ways to disrupt the spread of
B. burgdorferi
in nature.
Sub-genomic RNAi-assisted strain evolution of filamentous fungi for enhanced protein production
Authors: Sun Xianhua , Gao Fei , Fan Chao , Yang Shuyan , Zhao Tong , Tu Tao , Luo Huiying , Yao Bin , Huang Huoqing , Su Xiaoyun 
Published: June 2024

ABSTRACT

Genetic engineering at the genomic scale provides a rapid means to evolve microbes for desirable traits. However, in many filamentous fungi, such trials are daunted by low transformation efficiency. Differentially expressed genes under certain conditions may contain important regulatory factors. Accordingly, although manipulating these subsets of genes only can largely reduce the time and labor, engineering at such a sub-genomic level may also be able to improve the microbial performance. Herein, first using the industrially important cellulase-producing filamentous fungus
Trichoderma reesei
as a model organism, we constructed suppression subtractive hybridization (SSH) libraries enriched with differentially expressed genes under cellulase induction (MM-Avicel) and cellulase repression conditions (MM-Glucose). The libraries, in combination with RNA interference, enabled sub-genomic engineering of
T. reesei
for enhanced cellulase production. The ability of
T. reesei
to produce endoglucanase was improved by 2.8~3.3-fold. In addition, novel regulatory genes (
tre49304
,
tre120391
, and
tre123541
) were identified to affect cellulase expression in
T. reesei
. Iterative manipulation using the same strategy further increased the yield of endoglucanase activity to 75.6 U/mL, which was seven times as high as that of the wild type (10.8 U/mL). Moreover, using
Humicola insolens
as an example, such a sub-genomic RNAi-assisted strain evolution proved to be also useful in other industrially important filamentous fungi.
H. insolens
is a filamentous fungus commonly used to produce catalase, albeit with similarly low transformation efficiency and scarce knowledge underlying the regulation of catalase expression. By combining SSH and RNAi, a strain of
H. insolens
producing 28,500 ± 288 U/mL of catalase was obtained, which was 1.9 times as high as that of the parent strain.

IMPORTANCE

Genetic engineering at the genomic scale provides an unparalleled advantage in microbial strain improvement, which has previously been limited only to the organisms with high transformation efficiency such as
Saccharomyces cerevisiae
and
Escherichia coli
. Herein, using the filamentous fungus
Trichoderma reesei
as a model organism, we demonstrated that the advantage of suppression subtractive hybridization (SSH) to enrich differentially expressed genes and the convenience of RNA interference to manipulate a multitude of genes could be combined to overcome the inadequate transformation efficiency. With this sub-genomic evolution strategy,
T. reesei
could be iteratively engineered for higher cellulase production. Intriguingly,
Humicola insolens
, a fungus with even little knowledge in gene expression regulation, was also improved for catalase production. The same strategy may also be expanded to engineering other microorganisms for enhanced production of proteins, organic acids, and secondary metabolites.
Recognition of
Chlamydia trachomatis
by Toll-like receptor 9 is altered during persistence
Authors: Diallo Aissata , Overman Grace , Sah Prakash , Liechti George W. 
Published: June 2024

ABSTRACT

Toll-like receptor 9 (TLR9) is an innate immune receptor that localizes to endosomes in antigen presenting cells and recognizes single stranded unmethylated CpG sites on bacterial genomic DNA (gDNA). Previous bioinformatic studies have demonstrated that the genome of the human pathogen
Chlamydia trachomatis
contains TLR9 stimulatory motifs, and correlative studies have implied a link between human TLR9 (hTLR9) genotype variants and susceptibility to infection. Here, we present our evaluation of the stimulatory potential of
C. trachomatis
gDNA and its recognition by hTLR9- and murine TLR9 (mTLR9)-expressing cells. Utilizing reporter cell lines, we demonstrate that purified gDNA from
C. trachomatis
can stimulate hTLR9 signaling, albeit at lower levels than gDNA prepared from other Gram-negative bacteria. Interestingly, we found that while
C. trachomatis
is capable of signaling through hTLR9 and mTLR9 during live infections in HEK293 reporter cell lines, signaling only occurs at later developmental time points. Chlamydia-specific induction of hTLR9 is blocked when protein synthesis is inhibited prior to the RB-to-EB conversion, exacerbated by the inhibition of lipooligosaccharide biosynthesis, and is significantly altered during the induction of aberrance/persistence. Our observations support the hypothesis that chlamydial gDNA is released during the conversion between the pathogen’s replicative and infectious forms and during treatment with antibiotics targeting peptidoglycan assembly. Given that
C. trachomatis
inclusions do not co-localize with TLR9-containing vacuoles in the pro-monocytic cell line U937, our findings also hint that chlamydial gDNA is capable of egress from the inclusion, and traffics to TLR9-containing vacuoles via an as yet unknown pathway.
Ribosomal-processing cysteine protease homolog modulates
Streptococcus mutans
glucan production and interkingdom interactions
Authors: Treerat Puthayalai , de Mattos Camilla , Burnside Molly , Zhang Hua , Zhu Yanting , Zou Zhengzhong , Anderson David , Wu Hui , Merritt Justin , Kreth Jens 
Published: June 2024

ABSTRACT

Glucan-dependent biofilm formation is a crucial process in the establishment of
Streptococcus mutans
as a cariogenic oral microbe. The process of glucan formation has been investigated in great detail, with glycosyltransferases GtfB, GtfC, and GtfD shown to be indispensable for the synthesis of glucans from sucrose. Glucan production can be visualized during biofilm formation through fluorescent labeling, and its abundance, as well as the effect of glucans on general biofilm architecture, is a common phenotype to study
S. mutans
virulence regulation. Here, we describe an entirely new phenotype associated with glucan production, caused by a mutation in the open reading frame SMU_848, which is located in an operon encoding ribosome-associated proteins. This mutation led to the excess production and accumulation of glucan-containing droplets on the surface of biofilms formed on agar plates after prolonged incubation. While not characterized in
S. mutans
, SMU_848 shows homology to the phage-related ribosomal protease Prp, essential in cleaving off the N-terminal extension of ribosomal protein L27 for functional ribosome assembly in
Staphylococcus aureus
. We present a further characterization of SMU_848/Prp, demonstrating that the deletion of this gene leads to significant changes in
S. mutans gtfBC
expression. Surprisingly, it also profoundly impacts the interkingdom interaction between
S. mutans
and
Candida albicans
, a relevant dual-species interaction implicated in severe early childhood caries. The presented data support a potential broader role for SMU_848/Prp, possibly extending its functionality beyond the ribosomal network to influence important ecological processes.

IMPORTANCE

Streptococcus mutans
is an important member of the oral biofilm and is implicated in the initiation of caries. One of the main virulence mechanisms is the glucan-dependent formation of biofilms. We identified a new player in the regulation of glucan production, SMU_848, which is part of an operon that also encodes for ribosomal proteins L27 and L21. A mutation in SMU_848, which encodes a phage-related ribosomal protease Prp, leads to a significant accumulation of glucan-containing droplets on
S. mutans
biofilms, a previously unknown phenotype. Further investigations expanded our knowledge about the role of SMU_848 beyond its role in glucan production, including significant involvement in interkingdom interactions, thus potentially playing a global role in the virulence regulation of
S. mutans
.
Herpes simplex virus type-1 cVAC formation in neuronal cells is mediated by dynein motor function and glycoprotein retrieval from the plasma membrane
Authors: White Shaowen , Roller Richard 
Published: June 2024

ABSTRACT

Herpesvirus assembly requires the cytoplasmic association of large macromolecular and membrane structures that derive from both the nucleus and cytoplasmic membrane systems. Results from the study of human cytomegalovirus (HCMV) in cells where it organizes a perinuclear cytoplasmic virus assembly compartment (cVAC) show a clear requirement for the minus-end-directed microtubule motor, dynein, for virus assembly. In contrast, the assembly of herpes simplex virus -1 (HSV-1) in epithelial cells where it forms multiple dispersed, peripheral assembly sites is only mildly inhibited by the microtubule-depolymerizing agent, nocodazole. Here, we make use of a neuronal cell line system in which HSV-1 forms a single cVAC and show that dynein and its co-factor dynactin localize to the cVAC, and dynactin is associated with membranes that contain the virion tegument protein pUL11. We also show that the virus membrane-associated structural proteins pUL51 and the viral envelope glycoprotein gE arrive at the cVAC by different routes. Specifically, gE arrives at the cVAC after retrieval from the plasma membrane, suggesting the need for an intact retrograde transport system. Finally, we demonstrate that inhibition of dynactin function profoundly inhibits cVAC formation and virus production during the cytoplasmic assembly phase of infection.

IMPORTANCE
Many viruses reorganize cytoplasmic membrane systems and macromolecular transport systems to promote the production of progeny virions. Clarifying the mechanisms by which they accomplish this may reveal novel therapeutic strategies and illustrate mechanisms that are critical for normal cellular organization. Here, we explore the mechanism by which HSV-1 moves macromolecular and membrane cargo to generate a virus assembly compartment in the infected cell. We find that the virus makes use of a well-characterized, microtubule-based transport system that is stabilized against drugs that disrupt microtubules.
The respiratory and fecal microbiota of beef calves from birth to weaning
Authors: Uddin Muhammed Salah , Ortiz Guluarte Jose , Waldner Matthew , Alexander Trevor W. 
Published: June 2024

ABSTRACT

The development and growth of animals coincide with the establishment and maturation of their microbiotas. To evaluate the respiratory and fecal microbiotas of beef calves from birth to weaning, a total of 30 pregnant cows, and their calves at birth, were enrolled in this study. Deep nasal swabs and feces were collected from calves longitudinally, starting on the day of birth and ending on the day of weaning. Nasopharyngeal, vaginal, and fecal samples were also collected from cows, and the microbiotas of all samples were analyzed. The fecal microbiota of calves was enriched with
Lactobacillus
during the first 8 weeks of life, before being displaced by genera associated with fiber digestion, and then increasing in diversity across time. In contrast, the diversity of calf respiratory microbiota generally decreased with age. At birth, the calf and cow nasal microbiotas were highly similar, indicating colonization from dam contact. This was supported by microbial source-tracking analysis. The structure of the calf nasal microbiota remained similar to that of the cows, until weaning, when it diverged. The changes were driven by a decrease in
Lactobacillus
and an increase in genera typically associated with bovine respiratory disease, including
Mannheimia
,
Pasteurella
, and
Mycoplasma
. These three genera colonized calves early in life, though
Mannheimia
was initially transferred from the cow reproductive tract. Path analysis was used to model the interrelationships of calf respiratory and fecal microbiotas. It was observed that respiratory
Lactobacillus
and fecal
Oscillospiraceae
UCG-005 negatively affected the abundance of
Mannheimia
or
Pasteurella
.

IMPORTANCE
In beef cattle production, bovine respiratory disease (BRD) accounts for most of the feedlot morbidities and mortalities. Metaphylaxis is a common management tool to mitigate BRD, however its use has led to increased antimicrobial resistance. Novel methods to mitigate BRD are needed, including microbiota-based strategies. However, information on the respiratory bacteria of beef calves prior to weaning was limited. In this study, it was shown that the microbiota of cows influenced the initial composition of both respiratory and fecal microbiotas in calves. While colonization of the respiratory tract of calves by BRD-associated genera occurred early in life, their relative abundances increased at weaning, and were negatively correlated with respiratory and gut bacteria. Thus, microbiotas of both the respiratory and gastrointestinal tracts have important roles in antagonism of respiratory pathogens and are potential targets for enhancing calf respiratory health. Modulation may be most beneficial, if done prior to weaning, before opportunistic pathogens establish colonization.
c-di-AMP accumulation impairs toxin expression of
Bacillus anthracis
by down-regulating potassium importers
Authors: Hu Jia , Yao Junmin , Lei Chengfeng , Sun Xiulian 
Published: June 2024

ABSTRACT

The Gram-positive bacterium
Bacillus anthracis
is the causative agent of anthrax and a bioterrorism threat worldwide. As a crucial second messenger in many bacterial species, cyclic di-AMP (c-di-AMP) modulates various key processes for bacterial homeostasis and pathogenesis. Overaccumulation of c-di-AMP alters cellular growth and reduces anthrax toxin expression as well as virulence in
Bacillus anthracis
by unresolved underlying mechanisms. In this report, we discovered that c-di-AMP binds to a series of receptors involved in potassium uptake in
B. anthracis
. By analyzing Kdp and Ktr mutants for osmotic stress, gene expression, and anthrax toxin expression, we also showed that c-di-AMP inhibits Kdp operon expression through binding to the KdpD and
ydaO
riboswitch; up-regulating intracellular potassium promotes anthrax toxin expression in c-di-AMP accumulated
B. anthracis
. Decreased anthrax toxin expression at high c-di-AMP occurs through the inhibition of potassium uptake. Understanding the molecular basis of how potassium uptake affects anthrax toxin has the potential to provide new insight into the control of
B. anthracis.

IMPORTANCE

The bacterial second messenger cyclic di-AMP (c-di-AMP) is a conserved global regulator of potassium homeostasis. How c-di-AMP regulates bacterial virulence is unknown. With this study, we provide a link between potassium uptake and anthrax toxin expression in
Bacillus anthracis
. c-di-AMP accumulation might inhibit anthrax toxin expression by suppressing potassium uptake.
Potential bed-day savings and caregiver perspectives of transitioning hospital-level management of infants with bronchiolitis to the home: a mixed-methods study
Authors: Lawrence Joanna , Hiscock Harriet , Bryant Penelope A , Greig Genevieve , Sharma Anurag , Walpola Ramesh 
Published: June 2024

ObjectiveHome management of infants admitted to hospital with bronchiolitis would alleviate pressure on hospital beds. We aim to understand the proportion of children requiring active care interventions (ie, oxygen, fluids), caregiver perspectives and potential impact of transitioning hospital-level care of infants with bronchiolitis to home.MethodsThis is a mixed-methods study in an Australian tertiary paediatric hospital. Semistructured interviews with caregivers of infants with bronchiolitis focused on attitudes towards managing bronchiolitis at home. Interviews were analysed using inductive thematic analysis. Data on bronchiolitis admissions among infants aged 1–12 months were extracted from the electronic medical record from April 2016 to October 2020. Potential bed-days saved were calculated.Results18 parents were interviewed, with themes emerging of ‘hospital is safe’, ‘hospital incurs costs’ and ‘knowledge is power’. During 4.5 years, 2367 infants were admitted to hospital with bronchiolitis: a total of 4557 bed-days. Of these, 40% of infants were admitted for monitoring alone, 25% for nasogastric fluid support, 17% for oxygen therapy and 7.5% for both fluids and oxygen. 11% received treatments not currently feasible at home (high-flow oxygen, intravenous fluids). Oxygen therapy accounted for the largest number of bed-days (242 bed-days/year).ConclusionManaging bronchiolitis at home could have a substantial impact on hospital bed demand, with an estimated 344 bed-days saved per year if all interventions were offered. Parent willingness to transfer to home balances the perceived safety of the hospital versus the financial, logistic and emotional costs. Empowering parents with knowledge was seen as a substantial facilitator of supporting transition to the home.