bluuebunny/crossref_metadata_2025 huggingface dataset:
Intervention Reflecting Motivation to Achieve Long-term Goals
Authors: Kataoka Rintaro , Shimakawa Hiromitsu , Harada Fumiko
Published: May 2024

This study proposes a method to identify interventions appropriate to each motivation to achieve goals. People must stay motivated to engage themselves in working hard over a long time toward goals. Some kinds of intervention work well, while others fail. This method requests them to express their reflections on the engagement in daily behavior toward the goals. It converts the expression into a vector representing their motivational state using the word embedding technology. The method sends messages that reflect the motivational states to examine changes in the motivation when people receive messages. It identifies what types of messages encourage/discourage people with different motivations. In a 6-week experiment with 14 undergraduate and graduate students, intervention with messages is sent to their smartphones. The experiment results reveal messages improving/degrading motivation depending on the current motivational states of subjects, which enable us to provide more effective interventions for users trying to achieve a big goal in a long time.
Discrete spectrum of the magnetic Laplacian on perturbed half‐planes
Authors: Bonnaillie‐Noël Virginie , Fournais Søren , Kachmar Ayman , Raymond Nicolas
Published: May 2024

The existence of bound states for the magnetic Laplacian in unbounded domains can be quite challenging in the case of a homogeneous magnetic field. We provide an affirmative answer for almost flat corners and slightly curved half‐planes when the total curvature of the boundary is positive.
Discussion of “A Multi-Objective Comprehensive Evaluation of Heat Transfer Performance of a Direct-Contact Heat Exchanger” (Li, B., Yang, P., Li, Z., Xu, J., and Wang, H., 2023, ASME J. Therm. Sci. Eng. Appl., 15(1), p. 011014)
Authors: Awad M. M.
Published: May 2024

The units of entransy dissipation (G) in Nomenclature are wrong. Also, an opinion on the concept of entransy is presented.
Contrast-enhanced ultrasound versus conventional ultrasound in guided liver puncture biopsy: a systematic review and meta-analysis
Authors: Yang Lidan , Zhang Ting , Wang Lei , Du Juan , Zhang Hao , Yi Wenquan
Published: May 2024

Aim: To evaluate the contrast-enhanced ultrasound (CEUS) versus conventional ultrasound (US) in guided liver puncture biopsy through a systematic review and meta-analysis.Material and methods: Comparative studies on CEUS and US in liver puncture biopsy were systematically searched from PubMed, Embase, Cochrane library, Chinese Biomedical Literature Database. Two researchers independently screened and extracted data, and RevMan 5.3 software was used for data analysis.Results: The area under the curve (AUC) for CEUS and US in diagnosing liver biopsy was 0.98 (95%CI 0.99-0.97) and 0.95 (95%CI 0.97-0.93), respectively. CEUS demonstrated significantly higher single puncture success rate (38.0% vs 36.4%) [OR=2.67; 95% CI 1.38-5 .17; p=0 .003] and pathological diagnosis rate (95.6% vs 90.5%) [OR =4.35; 95%CI 2.25 -8.39; p<0 .001] compared to the US group. The diagnostic accuracy of the CEUS group was 95.6 % (1964/2054), while that of the US group was 90.5% (1729/1909). The combined analysis indicated significant advantages for CEUS over US [(OR = 2.36). 95 %CI 1.81-3.09, p<0.001].Conclusions: CEUS is superior to US in the diagnostic performance, single puncture success rate, pathological diagnosis rate and diagnostic accuracy of liver biopsy in patients with liver lesions.
Evaluation of the correlation of wall elasticity between different sections of radial artery by velocity vector imaging
Authors: Tong Ge , Gao Yihua , Yuan Dandan
Published: May 2024

Aim: This study aimed to evaluate the correlation between the elasticity of the anterior and posterior walls of the radial artery in different sections using velocity vector imaging.Material and methods: In this retrospective analysis, 30 healthy people who underwent physical examination in our hospital from January 2022 to January 2023 were analyzed offline by velocity vector imaging technology. The following parameters were assessed: peak systolic strain (Ss; %), peak diastolic strain (Sd; %), peak systolic strain rate (SRs; 1/s), and peak diastolic strain rate (SRd; 1/s). Elastic function was evaluated by analyzing the systolic and diastolic motion of the arterial walls.Result: In the long-axis sections, there was a significant positive correlation between Ss, SRs, and SRd of both the anterior and posterior walls (r=0.531, r=0.803, and r=0.898, all p<0.01). Additionally, Sd showed a positive correlation (r=0.402, p<0.05). In the short-axis sections, there was a significant and positive correlation between SRs and SRd of both walls (r=0.762, r=0.667, both p<0.01). Furthermore, a positive correlation was found between SRd in the long-axis and short-axis sections of the anterior wall (r=0.382, p<0.05).Conclusions: Velocity vector imaging is a valuable tool for assessing the elasticity of the radial artery in different sections, and the longitudinal SRd in the long-axis section may serve as a highly sensitive and accurate parameter for assessing changes in wall elastic function during the occurrence of radial artery lesions.
Residual stress depth profiles self-developed in cathodic arc deposited Ti-Al-N coatings prepared at different constant substrate bias values
Authors: Varela L. B. , Avila P. R. T. , Miletić A. , Bousser E. , Mendez J. M. , Klemberg-Sapieha J. E. , Martinu L.
Published: May 2024

Ti-Al-N coatings were prepared by cathodic arc deposition on Inconel 718 substrates at different values of constant substrate bias voltage, aiming to produce samples with different self-developed residual stress (RS) depth profiles through the thickness of the coatings. RS profile measurements and structural characterization were performed on a laboratory-scale x-ray diffraction system (x-ray energy of 8 keV) and in a synchrotron x-ray radiation facility (x-ray energy of 15 keV). Mechanical testing to obtain hardness and Young’s modulus values was performed by instrumented nanoindentation. The results indicate higher compressive RS at the film/substrate interface that decays to lower compressive stress or mild tensile stress at the film surface. Surface hardness and the compressive RS value of the coating increase with larger values of the substrate bias voltage. By comparing the stress characterization done on a laboratory scale and at the synchrotron facility, one observes a generally good agreement, indicating that these analyses may be conducted at a smaller scale and with less costly equipment, and still maintain a reliable precision. The work presents and reviews in detail the methodology of the RS depth-profile analysis. The highest hardness of 31.1 GPa and near-substrate compressive RS around −10 GPa were obtained for a bias of −100 V. Transmission electron microscopy results indicate that regions with higher compressive stresses are found to have smaller columns and denser structure, while portions of the same sample with mild compressive or tensile stresses present larger column size and are richer in hexagonal phases. The findings demonstrate the complex interplay between stress, microstructure, and ultimately mechanical properties in industrially produced Ti-Al-N coatings and indicate that any successful strategy to mitigate stress development should consider the inhomogeneous self-developed stress gradients present even in coatings deposited under constant and controlled conditions.
Resolving and correcting for kinetic biases on methane seep paleotemperature using carbonate ∆
47
/∆
48
analysis
Authors: Staudigel Philip , Feng Dong , Peckmann Jörn , Bernecker Miguel , Davies Amelia , Tagliavento Mattia , Fiebig Jens
Published: May 2024

Methane-derived authigenic carbonate often constitutes the sole remaining record of relic methane seeps. The clumped (∆
47
) and oxygen isotopic composition of seep carbonates often yield inaccurate temperatures, attributed to kinetic isotope effects and modification of seawater isotope composition by hydrate water. Here, we analyzed the dual-clumped isotope (∆
47
/∆
48
) composition of authigenic carbonate from a modern methane seep. We demonstrate that aragonite forms closest to isotopic equilibrium such that its ∆
47
can directly yield the correct formational temperature, whereas calcite is unambiguously biased by kinetic isotope effects. Numerical models show that the observed bias in the isotopic composition arises from rate-limiting dehydration/dehydroxylation of HCO
3
−
alongside diffusive fractionation, which can be corrected for with analysis of carbonate ∆
47
/∆
48
values. We demonstrate the utility of dual-clumped isotope analysis for studying seep carbonates, as it reveals the origin and magnitude of kinetic biases and can be used to reconstruct paleotemperature and seawater δ
18
O.
Vaccine targeting to mucosal lymphoid tissues promotes humoral immunity in the gastrointestinal tract
Authors: Kocabiyik Ozgun , Amlashi Parastoo , Vo A. Lina , Suh Heikyung , Rodriguez-Aponte Sergio A. , Dalvie Neil C. , Love J. Christopher , Andrabi Raiees , Irvine Darrell J.
Published: May 2024

Viruses, bacteria, and parasites frequently cause infections in the gastrointestinal tract, but traditional vaccination strategies typically elicit little or no mucosal antibody responses. Here, we report a strategy to effectively concentrate immunogens and adjuvants in gut-draining lymph nodes (LNs) to induce gut-associated mucosal immunity. We prepared nanoemulsions (NEs) based on biodegradable oils commonly used as vaccine adjuvants, which encapsulated a potent Toll-like receptor agonist and displayed antigen conjugated to their surface. Following intraperitoneal administration, these NEs accumulated in gut-draining mesenteric LNs, priming strong germinal center responses and promoting B cell class switching to immunoglobulin A (IgA). Optimized NEs elicited 10- to 1000-fold higher antigen-specific IgG and IgA titers in the serum and feces, respectively, compared to free antigen mixed with NE, and strong neutralizing antibody titers against severe acute respiratory syndrome coronavirus 2. Thus, robust gut humoral immunity can be elicited by exploiting the unique lymphatic collection pathways of the gut with a lymph-targeting vaccine formulation.
Presynaptic nanoscale components of retrograde synaptic signaling
Authors: Barti Benjámin , Dudok Barna , Kenesei Kata , Zöldi Miklós , Miczán Vivien , Balla Gyula Y. , Zala Diana , Tasso Mariana , Sagheddu Claudia , Kisfali Máté , Tóth Blanka , Ledri Marco , Vizi E. Sylvester , Melis Miriam , Barna László , Lenkei Zsolt , Soltész Iván , Katona István
Published: May 2024

While our understanding of the nanoscale architecture of anterograde synaptic transmission is rapidly expanding, the qualitative and quantitative molecular principles underlying distinct mechanisms of retrograde synaptic communication remain elusive. We show that a particular form of tonic cannabinoid signaling is essential for setting target cell–dependent synaptic variability. It does not require the activity of the two major endocannabinoid-producing enzymes. Instead, by developing a workflow for physiological, anatomical, and molecular measurements at the same unitary synapse, we demonstrate that the nanoscale stoichiometric ratio of type 1 cannabinoid receptors (CB
1
Rs) to the release machinery is sufficient to predict synapse-specific release probability. Accordingly, selective decrease of extrasynaptic CB
1
Rs does not affect synaptic transmission, whereas in vivo exposure to the phytocannabinoid Δ
9
-tetrahydrocannabinol disrupts the intrasynaptic nanoscale stoichiometry and reduces synaptic variability. These findings imply that synapses leverage the nanoscale stoichiometry of presynaptic receptor coupling to the release machinery to establish synaptic strength in a target cell–dependent manner.
Surface plasmons-phonons for mid-infrared hyperspectral imaging
Authors: Zhou Hong , Li Dongxiao , Ren Zhihao , Xu Cheng , Wang Lin-Fa , Lee Chengkuo
Published: May 2024

Surface plasmons have proven their ability to boost the sensitivity of mid-infrared hyperspectral imaging by enhancing light-matter interactions. Surface phonons, a counterpart technology to plasmons, present unclear contributions to hyperspectral imaging. Here, we investigate this by developing a plasmon-phonon hyperspectral imaging system that uses asymmetric cross-shaped nanoantennas composed of stacked plasmon-phonon materials. The phonon modes within this system, controlled by light polarization, capture molecular refractive index intensity and lineshape features, distinct from those observed with plasmons, enabling more precise and sensitive molecule identification. In a deep learning–assisted imaging demonstration of severe acute respiratory syndrome coronavirus (SARS-CoV), phonons exhibit enhanced identification capabilities (230,400 spectra/s), facilitating the de-overlapping and observation of the spatial distribution of two mixed SARS-CoV spike proteins. In addition, the plasmon-phonon system demonstrates increased identification accuracy (93%), heightened sensitivity, and enhanced detection limits (down to molecule monolayers). These findings extend phonon polaritonics to hyperspectral imaging, promising applications in imaging-guided molecule screening and pharmaceutical analysis.
Excitation of natural spinal reflex loops in the sensory-motor control of hand prostheses
Authors: Sagastegui Alva Patrick G. , Boesendorfer Anna , Aszmann Oskar C. , Ibáñez Jaime , Farina Dario
Published: May 2024

Sensory feedback for prosthesis control is typically based on encoding sensory information in specific types of sensory stimuli that the users interpret to adjust the control of the prosthesis. However, in physiological conditions, the afferent feedback received from peripheral nerves is not only processed consciously but also modulates spinal reflex loops that contribute to the neural information driving muscles. Spinal pathways are relevant for sensory-motor integration, but they are commonly not leveraged for prosthesis control. We propose an approach to improve sensory-motor integration for prosthesis control based on modulating the excitability of spinal circuits through the vibration of tendons in a closed loop with muscle activity. We measured muscle signals in healthy participants and amputees during different motor tasks, and we closed the loop by applying vibration on tendons connected to the muscles, which modulated the excitability of motor neurons. The control signals to the prosthesis were thus the combination of voluntary control and additional spinal reflex inputs induced by tendon vibration. Results showed that closed-loop tendon vibration was able to modulate the neural drive to the muscles. When closed-loop tendon vibration was used, participants could achieve similar or better control performance in interfaces using muscle activation than without stimulation. Stimulation could even improve prosthetic grasping in amputees. Overall, our results indicate that closed-loop tendon vibration can integrate spinal reflex pathways in the myocontrol system and open the possibility of incorporating natural feedback loops in prosthesis control.
Zafirlukast, as a viral inactivator, potently inhibits infection of several flaviviruses, including Zika virus, dengue virus, and yellow fever virus
Authors: Chen Yongkang , Li Yuan , Lu Lu , Zou Peng
Published: May 2024

Zika virus (ZIKV) is one of the mosquito-borne flaviviruses that exhibits a unique tropism to nervous systems and is associated with Guillain-Barre syndrome and congenital Zika syndrome (CZS). Dengue virus (DENV) and yellow fever virus (YFV), the other two mosquito-borne flaviviruses, have also been circulating for a long time and cause severe diseases, such as dengue hemorrhagic fever and yellow fever, respectively. However, there are no safe and effective antiviral drugs approved for the treatment of infections or coinfections of these flaviviruses. Here, we found that zafirlukast, a pregnancy-safe leukotriene receptor antagonist, exhibited potent antiviral activity against infections of ZIKV strains from different lineages in diﬀerent cell lines, as well as against infections of DENV-2 and YFV 17D. Mechanistic studies demonstrated that zafirlukast directly and irreversibly inactivated these flaviviruses by disrupting the integrity of the virions, leading to the loss of viral infectivity, hence inhibiting the entry step of virus infection. Considering its efficacy against flaviviruses, its safety for pregnant women, and its neuroprotective effect, zafirlukast is a promising candidate for prophylaxis and treatment of infections or coinfections of ZIKV, DENV, and YFV, even in pregnant women.
Enhancing glucaric acid production from
myo
-inositol in
Escherichia coli
by eliminating cell-to-cell variation
Authors: Ding Nana , Sun Lei , Zhou Xuan , Zhang Linpei , Deng Yu , Yin Lianghong
Published: May 2024

Glucaric acid (GA) is a value-added chemical and can be used to manufacture food additives, anticancer drugs, and polymers. The non-genetic cell-to-cell variations in GA biosynthesis are naturally inherent, indicating the presence of both high- and low-performance cells in culture. Low-performance cells can lead to nutrient waste and inefficient production. Furthermore,
myo
-inositol oxygenase (MIOX) is a key rate-limiting enzyme with the problem of low stability and activity in GA production. Therefore, eliminating cell-to-cell variations and increasing MIOX stability can select high-performance cells and improve GA production. In this study, an
in vivo
GA bioselector was constructed based on GA biosensor and tetracycline efflux pump protein TetA to continuously select GA-efficient production strains. Additionally, the upper limit of the GA biosensor was improved to 40 g/L based on ribosome-binding site optimization, achieving efficient enrichment of GA high-performance cells. A small ubiquitin-like modifier (SUMO) enhanced MIOX stability and activity. Overall, we used the GA bioselector and SUMO-MIOX fusion in fed-batch GA production and achieved a 5.52-g/L titer in
Escherichia coli
, which was 17-fold higher than that of the original strain.

IMPORTANCE

Glucaric acid is a non-toxic valuable product that was mainly synthesized by chemical methods. Due to the problems of non-selectivity, inefficiency, and environmental pollution, GA biosynthesis has attracted significant attention. The non-genetic cell-to-cell variations and MIOX stability were both critical factors for GA production. In addition, the high detection limit of the GA biosensor was a key condition for performing high-throughput screening of GA-efficient production strains. To increase GA titer, this work eliminated the cell-to-cell variations by GA bioselector constructed based on GA biosensor and TetA, and improved the stability and activity of MIOX in the GA biosynthetic pathway through fusing the SUMO to MIOX. Finally, these approaches improved the GA production by 17-fold to 5.52 g/L at 65 h. This study represents a significant step toward the industrial application of GA biosynthetic pathways in
E. coli
.
The novel regulator HdrR controls the transcription of the heterodisulfide reductase operon
hdrBCA
in
Methanosarcina barkeri
Authors: Zhang Sicheng , Chen Yi , Wang Shuxin , Yang Qing , Leng Huan , Zhao Pengyan , Guo Leizhou , Dai Lirong , Bai Liping , Cha Guihong
Published: May 2024

Methanogenic archaea play a key role in the global carbon cycle because these microorganisms remineralize organic compounds in various anaerobic environments. The microorganism
Methanosarcina barkeri
is a metabolically versatile methanogen, which can utilize acetate, methanol, and H
2
/CO
2
to synthesize methane. However, the regulatory mechanisms underlying methanogenesis for different substrates remain unknown. In this study, RNA-seq analysis was used to investigate
M. barkeri
growth and gene transcription under different substrate regimes. According to the results,
M. barkeri
showed the best growth under methanol, followed by H
2
/CO
2
and acetate, and these findings corresponded well with the observed variations in genes transcription abundance for different substrates. In addition, we identified a novel regulator, MSBRM_RS03855 (designated as HdrR), which specifically activates the transcription of the heterodisulfide reductase
hdrBCA
operon in
M. barkeri
. HdrR was able to bind to the
hdrBCA
operon promoter to regulate transcription. Furthermore, the structural model analyses revealed a helix-turn-helix domain, which is likely involved in DNA binding. Taken together, HdrR serves as a model to reveal how certain regulatory factors control the expression of key enzymes in the methanogenic pathway.

IMPORTANCE

The microorganism
Methanosarcina barkeri
has a pivotal role in the global carbon cycle and contributes to global temperature homeostasis. The consequences of biological methanogenesis are far-reaching, including impacts on atmospheric methane and CO
2
concentrations, agriculture, energy production, waste treatment, and human health. As such, reducing methane emissions is crucial to meeting set climate goals. The methanogenic activity of certain microorganisms can be drastically reduced by inhibiting the transcription of the
hdrBCA
operon, which encodes heterodisulfide reductases. Here, we provide novel insight into the mechanisms regulating
hdrBCA
operon transcription in the model methanogen
M. barkeri
. The results clarified that HdrR serves as a regulator of heterodisulfide reductase
hdrBCA
operon transcription during methanogenesis, which expands our understanding of the unique regulatory mechanisms that govern methanogenesis. The findings presented in this study can further our understanding of how genetic regulation can effectively reduce the methane emissions caused by methanogens.
Biological puzzles solved by using
Streptococcus pneumoniae
: a historical review of the pneumococcal studies that have impacted medicine and shaped molecular bacteriology
Authors: Hiller N. Luisa , Orihuela Carlos J.
Published: May 2024

The major human pathogen
Streptococcus pneumoniae
has been the subject of intensive clinical and basic scientific study for over 140 years. In multiple instances, these efforts have resulted in major breakthroughs in our understanding of basic biological principles as well as fundamental tenets of bacterial pathogenesis, immunology, vaccinology, and genetics. Discoveries made with
S. pneumoniae
have led to multiple major public health victories that have saved the lives of millions. Studies on
S. pneumoniae
continue today, where this bacterium is being used to dissect the impact of the host on disease processes, as a powerful cell biology model, and to better understand the consequence of human actions on commensal bacteria at the population level. Herein we review the major findings, i.e., puzzle pieces, made with
S. pneumoniae
and how, over the years, they have come together to shape our understanding of this bacterium’s biology and the practice of medicine and modern molecular biology.
Identification and characterization of zinc importers in
Corynebacterium diphtheriae
Authors: Peng Eric D. , Lyman Lindsey R. , Schmitt Michael P.
Published: May 2024

Corynebacterium diphtheriae
is the causative agent of diphtheria, a severe respiratory disease in humans.
C. diphtheriae
colonizes the human upper respiratory tract, where it acquires zinc, an essential metal required for survival in the host. While the mechanisms for zinc transport by
C. diphtheriae
are not well characterized, four putative zinc ABC-type transporter loci were recently identified in strain 1737:
iutABCD/E
(
iut
),
znuACB
(
znu
),
nikABCD1
(
nik1
), and
nikABCD2
(
nik2
). A mutant deleted for all four loci (Δ4) exhibited similar growth to that of the wild-type strain in a zinc-limited medium, suggesting there are additional zinc transporters. Two additional gene loci predicted to be associated with metal import,
mntABCD
(
mnt
) and
sidAB
(
sid
)
,
were deleted in the Δ4 mutant to construct a new mutant designated Δ6. The
C. diphtheriae
Δ6 mutant exhibited significantly reduced growth under zinc limitation relative to the wild type, suggesting a deficiency in zinc acquisition. Strains retaining the
iut
,
znu
,
mnt,
or
sid
loci grew to near-wild-type levels in the absence of the other five loci, indicating that each of these transporters may be involved in zinc uptake. Plasmid complementation with cloned
iut
,
znu
,
mnt
, or
nik1
loci also enhanced the growth of the Δ6 mutant. Quantification of intracellular zinc content by inductively coupled plasma mass spectrometry was consistent with reduced zinc uptake by Δ6 relative to the wild type and further supports a zinc uptake function for the transporters encoded by
iut
,
znu
, and
mnt
. This study demonstrates that
C. diphtheriae
zinc transport is complex and involves multiple zinc uptake systems.

IMPORTANCE

Zinc is a critical nutrient for all forms of life, including human bacterial pathogens. Thus, the tools that bacteria use to acquire zinc from host sources are crucial for pathogenesis. While potential candidates for zinc importers have been identified in
Corynebacterium diphtheriae
from gene expression studies, to date, no study has clearly demonstrated this function for any of the putative transporters. We show that
C. diphtheriae
encodes at least six loci associated with zinc import, underscoring the extent of redundancy for zinc acquisition. Furthermore, we provide evidence that a previously studied manganese-regulated importer can also function in zinc import. This study builds upon our knowledge of bacterial zinc transport mechanisms and identifies potential targets for future diphtheria vaccine candidates.
Effects of pleiotropic
ompR
and
envZ
alleles of
Escherichia coli
on envelope stress and antibiotic sensitivity
Authors: Gerken Henri , Shetty Dasvit , Kern Brea , Kenney Linda J. , Misra Rajeev
Published: May 2024

The EnvZ-OmpR two-component system of
Escherichia coli
regulates the expression of the
ompF
and
ompC
porin genes in response to medium osmolarity. However, certain mutations in
envZ
confer pleiotropy by affecting the expression of genes of the iron and maltose regulons not normally controlled by EnvZ-OmpR. In this study, we obtained two novel
envZ
and
ompR
pleiotropic alleles,
envZT15P
and
ompRL19Q
, among revertants of a mutant with heightened envelope stress and an outer membrane (OM) permeability defect. Unlike
envZ
, pleiotropic mutations in
ompR
have not been described previously. The mutant alleles reduced the expression of several outer membrane proteins (OMPs), overcame the temperature-sensitive growth defect of a protease-deficient (Δ
degP
) strain, and lowered envelope stress and OM permeability defects in a background lacking the BamB protein of an essential β-barrel assembly machinery complex. Biochemical analysis showed OmpRL19Q, like wild-type OmpR, is readily phosphorylated by EnvZ, but the EnvZ-dependent dephosphorylation of OmpRL19Q~P was drastically impaired compared to wild-type OmpR. This defect would lead to a prolonged half-life for OmpRL19Q~P, an outcome remarkably similar to what we had previously described for EnvZR397L, resulting in pleiotropy. By employing null alleles of the OMP genes, it was determined that the three pleiotropic alleles lowered envelope stress by reducing OmpF and LamB levels. The absence of LamB was principally responsible for lowering the OM permeability defect, as assessed by the reduced sensitivity of a Δ
bamB
mutant to vancomycin and rifampin. Possible mechanisms by which novel EnvZ and OmpR mutants influence EnvZ-OmpR interactions and activities are discussed.

IMPORTANCE

Maintenance of the outer membrane (OM) integrity is critical for the survival of Gram-negative bacteria. Several envelope homeostasis systems are activated when OM integrity is perturbed. Through the isolation and characterization of novel pleiotropic
ompR
/
envZ
alleles, this study highlights the involvement of the EnvZ-OmpR two-component system in lowering envelope stress and the OM permeability defect caused by the loss of proteins that are involved in OM biogenesis, envelope homeostasis, and structural integrity.
The chaperone PrsA2 regulates the secretion, stability, and folding of listeriolysin O during
Listeria monocytogenes
infection
Authors: Agbavor Charles , Zimnicka Adriana , Kumar Allison , George Jada L. , Torres Madeline , Prehna Gerd , Alonzo Francis , Durrant Jacob D. , Freitag Nancy E. , Cahoon Laty A.
Published: May 2024

Pathogenic bacteria rely on secreted virulence factors to cause disease in susceptible hosts. However, in Gram-positive bacteria, the mechanisms underlying secreted protein activation and regulation post-membrane translocation remain largely unknown. Using proteomics, we identified several proteins that are dependent on the secreted chaperone PrsA2. We followed with phenotypic, biochemical, and biophysical assays and computational analyses to examine the regulation of a detected key secreted virulence factor, listeriolysin O (LLO), and its interaction with PrsA2 from the bacterial pathogen
Listeria monocytogenes
(
Lm
). Critical to
Lm
virulence is internalization by host cells and the subsequent action of the cholesterol-dependent pore-forming toxin, LLO, which enables bacterial escape from the host cell phagosome. Since
Lm
is a Gram-positive organism, the space between the cell membrane and wall is solvent exposed. Therefore, we hypothesized that the drop from neutral to acidic pH as the pathogen is internalized into a phagosome is critical to regulating the interaction of PrsA2 with LLO. Here, we demonstrate that PrsA2 directly interacts with LLO in a pH-dependent manner. We show that PrsA2 protects and sequesters LLO under neutral pH conditions where LLO can be observed to aggregate. In addition, we identify molecular features of PrsA2 that are required for interaction and ultimately the folding and activity of LLO. Moreover, protein-complex modeling suggests that PrsA2 interacts with LLO via its cholesterol-binding domain. These findings highlight a mechanism by which a Gram-positive secretion chaperone regulates the secretion, stability, and folding of a pore-forming toxin under conditions relevant to host cell infection.

IMPORTANCE

Lm
is a ubiquitous food-borne pathogen that can cause severe disease to vulnerable populations. During infection,
Lm
relies on a wide repertoire of secreted virulence factors including the LLO that enables the bacterium to invade the host and spread from cell to cell. After membrane translocation, secreted factors must become active in the challenging bacterial cell membrane-wall interface. However, the mechanisms required for secreted protein folding and function are largely unknown.
Lm
encodes a chaperone, PrsA2, that is critical for the activity of secreted factors. Here, we show that PrsA2 directly associates and protects the major
Lm
virulence factor, LLO, under conditions corresponding to the host cytosol, where LLO undergoes irreversible denaturation. Additionally, we identify molecular features of PrsA2 that enable its interaction with LLO. Together, our results suggest that
Lm
and perhaps other Gram-positive bacteria utilize secreted chaperones to regulate the activity of pore-forming toxins during infection.
Draft genome sequences of multiple bacterial strains isolated from human feces
Authors: Selma-Royo Marta , Ricci Liviana , Golzato Davide , Servais Charlotte , Nabinejad Amir , Armanini Federica , Asnicar Francesco , Pinto Federica , Tamburini Sabrina , Segata Nicola
Published: May 2024

Bacterial isolation is necessary for functional and mechanistic analyses, and the increased human microbiome diversity revealed by metagenomic sequencing is expanding the relevant cultivation targets. Here, we report 46 draft genome sequences of bacterial isolates obtained from fecal samples of healthy adults in Trento and Milan (Italy), including strains from seven taxonomically uncharacterized species.
Draft genome sequences of three
Lactobacillus crispatus
strains, isolated from the female urinary tract
Authors: Sedano Cerena , Stegman Natalie , Steiling Maria , Jackson Briana , Putonti Catherine
Published: May 2024

Lactobacillus crispatus is
a frequent member of the female urogenital microbiota. Here, we present the draft genome assemblies of three
L. crispatus
strains: UMB4356, UMB5661, and UMB6244. All strains were isolated from voided urine samples from females with type 2 diabetes.
Salmonella enterica
subsp.
enterica
serovar Paratyphi B from mute swan (
Cygnus olor
): complete genome sequence features point towards invasive variant potential
Authors: Lamparter Marina C. , Borowiak Maria , Kutzer Peter , Schlieben Patricia , Szabo Istvan , Fischer Jennie
Published: May 2024

A subgroup of Salmonella (S.) enterica subsp. enterica serovar Paratyphi B is significantly associated with invasive infections in humans. We report the complete genome sequence of a potentially invasive.
S.
Paratyphi B isolated from a mute swan (
Cygnus olor
) found dead at an urban recreation park in Berlin, Germany.
Genomic characterization of circulating human respiratory syncytial viruses A and B in Kuwait using whole-genome sequencing
Authors: Madi Nada , Safar Hussain A. , Al-Adwani Anfal , Sadeq Mohammed , Al-Turab Mariam
Published: May 2024

The human respiratory syncytial virus (RSV) is considered one of the most common viruses that infect children globally. The virus is known to have extensive gene sequence variability within and between RSV groups A and B globally; however, there is no information on the whole-genome characterization and diversity of RSV in Kuwait. Therefore, this study aimed to sequence the entire genome of RSV strains isolated from patients with acute respiratory tract infection (ARTI) in Kuwait. Therefore, this study aimed to sequence the entire genome of RSV strains isolated from patients with ARTI in Kuwait. Between January 2020 and September 2022, 7,093 respiratory samples were collected from hospitalized infants, children, and adults and were analyzed for respiratory viruses by multiplex real-time PCR. Whole-genome sequencing using the Oxford Nanopore sequencing technology was performed on 84 RSV-positive samples. The results revealed a higher prevalence of group A (76%) than group B (24%) RSV isolates. Phylogenetic analysis showed that RSV-A strains clustered with the GA2.3.5 sub-genotype and RSV-B strains clustered with the GB5.0.5a sub-genotype; however, forming new lineages of RSV-A and RSV-B circulated in Kuwait during this period. Genetic variability was higher among the group A viruses than group B viruses, and the rate of synonymous and missense mutations was high in genes other than the G protein-coding gene. We also detected several known and unique molecular markers in different protein-coding genes. This is the first study in Kuwait to characterize the whole genomes of RSV A and B to identify the circulating genotypes, comprehend the genetic diversity and the evolution of the virus, and identify important genetic markers associated with specific genotypes.

IMPORTANCE

Whole-genome sequencing of respiratory syncytial virus (RSV) strains in Kuwait using MinION Nanopore technology was used to characterize and analyze the genotypes and sub-genotypes of the RSV circulating among patients with acute respiratory tract infections in Kuwait. This study also identified known and unknown gene mutations and imported genetic markers associated with specific genotypes. These results will assist in establishing a framework for RSV classification and allow for a better consideration of the mechanisms leading to the generation of diversity of RSV. In addition, these data will allow a comparison of vaccine viruses with those in Kuwait, providing useful insights into future vaccine and therapy strategies for RSV in Kuwait.
An observational study investigating soluble immune checkpoints as indicators of severe COVID-19
Authors: Cortés-Vieyra Ricarda , Gutiérrez-Castellanos Sergio , Gómez-García Anel , Bravo-Patiño Alejandro , Calderón-Rico Fernando , Martínez-Sepúlveda José Daniel , Ortega-Flores Roberto , Perez-Duran Francisco , Franco-Correa Luis Enrique , Zamora-Avilés Alicia Gabriela , Nuñez-Anita Rosa Elvira
Published: May 2024

This study aimed to investigate the immunomodulatory behavior of soluble immune checkpoints (sICPs) and other biomarkers in the pathophysiology of SARS-CoV-2 infection. The study included 59 adult participants, 43 of whom tested positive for SARS-CoV-2. Patients were divided into three cohorts: those with moderate disease (
n
= 16), recovered patients with severe disease (
n
= 13), and deceased patients with severe disease (
n
= 16). In addition, 16 participants were pre-pandemic subjects negative for SARS-CoV-2. The relative activity of neutralizing antibodies (rNAbs) against SARS-CoV-2 and the values of 14 sICPs in peripheral blood were compared between the four groups. Because the increase of markers values of inflammation [NLR > 12; CRP > 150 mg/L] and venous thromboembolism [D-dimer > 0.5 mg/L] has been associated with mortality from COVID-19, the total and differential leukocyte counts, the NLR, and CRP and D-dimer values were obtained in patients with severe disease. No differences in rNAbs were observed between the cohorts. Only the levels of five sICPs, sCD27, sHVEM sTIM-3, sPD-1, and sPDL-1, were significantly higher in patients with severe rather than moderate disease. The sPDL-2 level and NLR were higher in deceased patients than in recovered patients. However, there was no difference in CRP and D-dimer values between the two groups. Of the five soluble biomarkers compared among patients with severe disease, only sPDL-2 was higher in deceased patients than in recovered patients. This suggests that immuno-inhibitory sICPs might be used as indicators for severe COVID-19, with sPDL-2 used to assess individual risk for fatality.

IMPORTANCE

COVID-19, the disease caused by a SARS-CoV-2 infection, generates a broad spectrum of clinical symptoms, progressing to multiorgan failure in the most severe cases. As activation of the immune system is pivotal to eradicating the virus, future research should focus on identifying reliable biomarkers to efficiently predict the outcome in severe COVID-19 cases. Soluble immune checkpoints represent the function of the immune system and are easily determined in peripheral blood. This research could lead to implementing more effective severity biomarkers for COVID-19, which could increase patients’ survival rate and quality of life.
Recombinant
Beauveria bassiana
expressing
Bacillus thuringiensis
toxin Cyt1Aa: a promising approach for enhancing
Aedes
mosquito control
Authors: Deng Sheng-Qun , Li Ni , Yang Xu-Ke , Lu Hong-Zheng , Liu Jia-Hua , Peng Zhe-Yu , Wang Lin-Min , Zhang Mao , Zhang Chao , Chen Chen
Published: May 2024

The entomopathogenic fungus
Beauveria bassiana
provides an eco-friendly substitute to chemical insecticides for mosquito control. Nevertheless, its widespread application has been hindered by its comparatively slow efficacy in eliminating mosquitoes. To augment the potency of
B. bassiana
against
Aedes
mosquitoes, a novel recombinant strain,
Bb
-Cyt1Aa, was developed by incorporating the
Bacillus thuringiensis
toxin gene
Cyt1Aa
into
B. bassiana
. The virulence of
Bb
-Cyt1Aa was evaluated against
Aedes aegypti
and
Aedes albopictus
using insect bioassays. Compared to the wild-type (WT) strain, the median lethal time (LT
50
) for
A. aegypti
larvae infected with
Bb
-Cyt1Aa decreased by 33.3% at a concentration of 1 × 10
8
conidia/mL and by 22.2% at 1 × 10
7
conidia/mL. The LT
50
for
A. aegypti
adults infected with
Bb
-Cyt1Aa through conidia ingestion was reduced by 37.5% at 1 × 10
8
conidia/mL and by 33.3% at 1 × 10
7
conidia/mL. Likewise, the LT
50
for
A. aegypti
adults infected with
Bb
-Cyt1Aa through cuticle contact decreased by 33.3% and 30.8% at the same concentrations, respectively. Furthermore, the
Bb
-Cyt1Aa strain also demonstrated increased toxicity against both larval and adult
A. albopictus
, when compared to the WT strain. In conclusion, our study demonstrated that the expression of
B. thuringiensis
toxin Cyt1Aa in
B. bassiana
enhanced its virulence against
Aedes
mosquitoes. This suggests that
B. bassiana
expressing Cyt1Aa has potential value for use in mosquito control.

IMPORTANCE

Beauveria bassiana
is a naturally occurring fungus that can be utilized as a bioinsecticide against mosquitoes. Cyt1Aa is a delta-endotoxin protein produced by
Bacillus thuringiensis
that exhibits specific and potent insecticidal activity against mosquitoes. In our study, the expression of this toxin Cyt1Aa in
B. bassiana
enhances the virulence of
B. bassiana
against
Aedes aegypti
and
Aedes albopictus
, thereby increasing their effectiveness in killing mosquitoes. This novel strain can be used alongside chemical insecticides to reduce dependence on harmful chemicals, thereby minimizing negative impacts on the environment and human health. Additionally, the potential resistance of
B. bassiana
against mosquitoes in the future could be overcome by acquiring novel combinations of exogenous toxin genes. The presence of
B. bassiana
that expresses Cyt1Aa is of significant importance in mosquito control as it enhances genetic diversity, creates novel virulent strains, and contributes to the development of safer and more sustainable methods of mosquito control.
Microbiome of lovebug (
Plecia longiforceps
) in Seoul, South Korea
Authors: Yi Myung-hee , Choi Jun Ho , Kim Myungjun , Chavarria Xavier , Yun Sohyeon , Oh Singeun , Kang Dongjun , Yong Tai-Soon , Kim Ju Yeong
Published: May 2024

Lovebugs appeared in large numbers across a wide area in Seoul, South Korea, in June 2023. The sudden appearance of exotic insects not only discomforts people but also fosters anxiety, as their potential for pathogen transmission would be unknown. In this study, targeted next-generation sequencing (NGS) of the 16S rRNA gene V4 region was performed using iSeq 100 to screen for bacteria in lovebugs. Forty-one lovebugs (20 females and 21 males) collected in Seoul, Korea, were identified as
Plecia longiforceps
based on mitochondrial cytochrome oxidase subunit 1 sequencing data using PCR. We analyzed the microbiome of the lovebugs and detected 453 species of bacteria. Among all bacteria screened based on NGS,
Rickettsia
was detected in all samples with an average relative abundance of 80.40%, followed by
Pandoraea
and
Ewingella
. Diversity (alpha and beta) between females and males did not differ; however, only
Tumebacillus
showed a higher relative abundance in females. Sequencing analysis of
Rickettsia
using a
gltA
gene-specific primer by PCR showed that it had higher sequence similarity to the
Rickettsia
symbiont of arthropods than to the spotted fever group rickettsiae. Eleven samples in which
Pandoraea
was detected by iSeq 100 were confirmed by PCR and exhibited 100% sequence identity to
Pandoraea oxalativorans
strain DSM 23570. Consequently, the likelihood of pathogen transmission to humans is low. The applied method may play a crucial role in swiftly identifying bacterial species in the event of future outbreaks of exotic insects that may be harmful to humans.

IMPORTANCE

Lovebugs have recently emerged in large numbers in Seoul, causing major concern regarding potential health risks. By performing the next-generation sequencing of the 16S rRNA gene V4 region, we comprehensively examined the microbiome of these insects. We identified the presence of numerous bacteria, including
Rickettsia
and
Pandoraea
. Reassuringly, subsequent tests confirmed that these detected bacteria were not pathogenic. The present study addresses health concerns related to lovebugs and shows the accuracy and efficiency of our detection technique. Such methods prove invaluable for rapidly identifying bacterial species during potential outbreaks of unfamiliar insects, thereby ensuring public safety.
Career Reflections from a Chinese American Geology Professor
Authors: Chan Marjorie A.
Published: May 2024

I’ve enjoyed a rich career of four decades in academia as a Chinese American sedimentary geology professor. From the start, I was a clear minority, being nonwhite and a woman, but somehow with strong mentors and good fortune, I survived, persevered, and flourished. Despite discrimination and marginalization, there have been many positives, and the superb students and colleagues I have met on my journey have enriched my life immensely.

I want to see geoscience change to become one of the most inclusive sciences because it is really a capstone science that needs broad and diverse perspectives. I hope my story can encourage others and also highlight how we should continue to create opportunities for inclusive participation. The future of our Earth and the balance of nature and society depend on it!
Supplemental Material: Recognition of Neogene tin mineralization in the Southeast Asian tin belt
Authors: Huang Wen-Qing , Pan Jun-Yi , al. et
Published: May 2024

Supplemental Text S1: Analytical methods. Figure S1: Geochemical characterization of concentric oscillatory zones revealed by profile aa’. Figure S2: Geochemical characterization of the CL-dark sector zones revealed by profile bb’. Table S1: Trace-element results of the analyzed profiles in cassiterite from the Yunling deposit. Table S2: Cassiterite LA-ICP-MS U-Pb age data of Yunling deposit.
Haemophagocytic lymphohistiocytosis secondary to Epstein-Barr and cytomegalovirus coinfection
Authors: Nasir Ali Zagham , Khan Nasir
Published: May 2024

Haemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disorder caused by uncontrolled activation of the immune system, leading to phagocytosis of blood cells and cytokine storm. HLH can manifest in childhood due to a genetic mutation, but in adults HLH arises secondary to viral infections, autoimmune diseases or neoplastic processes. The most common viral infections associated with HLH are Epstein-Barr virus (EBV) and cytomegalovirus (CMV). EBV and CMV coinfection associated with HLH, however, is exceedingly rare. We present a case of HLH secondary to EBV and CMV coinfection in a young adult who presented with recurrent intermittent high-grade fevers and epistaxis. This case illustrates the importance of considering HLH in patients with idiopathic fevers and to consider all the potential aetiologies for HLH to ensure proper treatment.
Tracheal metallic hybrid stent removal via tracheostomy: an unconventional approach
Authors: Carção André , Cunha-Cabral Diogo , Neves Marta , Lopes Gustavo
Published: May 2024

Increasing use of tracheal expandable metallic hybrid stents will lead to common encounters with these devices in emergency airway management. The presence of these stents qualifies any patient as a challenge when an emergency tracheostomy is needed. We report an unorthodox technique of tracheostomy with concomitant removal of tracheal stent, without any major complications. Although the combined approach with bronchoscopy and tracheostomy has been reported in similar cases, we present a safe procedure when rigid bronchoscopy is not available.