bluuebunny/crossref_metadata_2025 huggingface dataset:
Sparse CBX2 nucleates many Polycomb proteins to promote facultative heterochromatinization of Polycomb target genes
Authors: Ingersoll Steven , Trouth Abby , Luo Xinlong , Espinoza Axel , Wen Joey , Tucker Joseph , Astatike Kalkidan , Phiel Christopher J. , Kutateladze Tatiana G. , Wu Tao P. , Ramachandran Srinivas , Ren Xiaojun
Published: February 2024

Facultative heterochromatinization of genomic regulators by Polycomb repressive complex (PRC) 1 and 2 is essential in development and differentiation; however, the underlying molecular mechanisms remain obscure. Using genetic engineering, molecular approaches, and live-cell single-molecule imaging, we quantify the number of proteins within condensates formed through liquid-liquid phase separation (LLPS) and find that in mouse embryonic stem cells (mESCs), approximately 3 CBX2 proteins nucleate many PRC1 and PRC2 subunits to form one non-stoichiometric condensate. We demonstrate that sparse CBX2 prevents Polycomb proteins from migrating to constitutive heterochromatin, demarcates the spatial boundaries of facultative heterochromatin, controls the deposition of H3K27me3, regulates transcription, and impacts cellular differentiation. Furthermore, we show that LLPS of CBX2 is required for the demarcation and deposition of H3K27me3 and is essential for cellular differentiation. Our findings uncover new functional roles of LLPS in the formation of facultative heterochromatin and unravel a new mechanism by which low-abundant proteins nucleate many other proteins to form compartments that enable them to execute their functions.
A disrupted compartment boundary underlies abnormal cardiac patterning and congenital heart defects
Authors: Kathiriya Irfan S. , Dominguez Martin H. , Rao Kavitha S. , Muncie-Vasic Jonathon M. , Devine W. Patrick , Hu Kevin M. , Hota Swetansu K. , Garay Bayardo I. , Quintero Diego , Goyal Piyush , Matthews Megan N. , Thomas Reuben , Sukonnik Tatyana , Perez Dario Miguel- , Winchester Sarah , Brower Emily F. , Forjaz André , Wu Pei-Hsun , Wirtz Denis , Kiemen Ashley L. , Bruneau Benoit G.
Published: February 2024

Failure of septation of the interventricular septum (IVS) is the most common congenital heart defect (CHD), but mechanisms for patterning the IVS are largely unknown. We show that aTbx5+/Mef2cAHF+progenitor lineage forms a compartment boundary bisecting the IVS. This coordinated population originates at a first- and second heart field interface, subsequently forming a morphogenetic nexus. Ablation ofTbx5+/Mef2cAHF+progenitors cause IVS disorganization, right ventricular hypoplasia and mixing of IVS lineages. Reduced dosage of the CHD transcription factor TBX5 disrupts boundary position and integrity, resulting in ventricular septation defects (VSDs) and patterning defects, includingSlit2andNtn1misexpression. Reducing NTN1 dosage partly rescues cardiac defects inTbx5mutant embryos. Loss ofSlit2orNtn1causes VSDs and perturbed septal lineage distributions. Thus, we identify essential cues that direct progenitors to pattern a compartment boundary for proper cardiac septation, revealing new mechanisms for cardiac birth defects.
Age Estimation from Blood Test Results Using a Random Forest Model
Authors: Kodera Satomi , Yokoi Osamu , Kaneko Masaki , Sato Yuka , Ito Susumu , Hata Katsuhiko
Published: February 2024

Background and Objectives

From the perspective of preventive medicine, in situations where screening tests are widely used, this study aims to clarify the role of screening data on ageing and health problems by estimating age from screening data with verifying the number of data items required.

Materials and Methods

A Python random forest model was generated using Chat GPT and tested.

Results

When using all 71 items, including gender, for the test results, a high accuracy of R2= 0.7010 was obtained when there were 9243 training data sets (80% of the total number of data sets). The R2 decreased slightly to 0.6937 when the number of data items was reduced to 15 by discarding lesser importance items. When the number of data sets were less than 800 or when the number of data items were less than 7, the R2value fell below 0.6. Interestingly, a higher age was tended to be estimated for post-menopausal women compared to pre-menopausal women.

Conclusions

The age estimated from blood data by the random forest model (blood age, so to speak) is so precise that it can be useful for assessing physical ageing state. However, the specific relationship between blood age and health status is still unclear, waiting for future research in order to deepen our understanding of this area.
SARS-CoV-2 booster vaccine dose significantly extends humoral immune response half-life beyond the primary series
Authors: Korosec Chapin S. , Dick David W. , Moyles Iain R. , Watmough James
Published: February 2024

SARS-CoV-2 lipid nanoparticle mRNA therapeutics continue to be administered as the predominant therapeutic intervention to reduce COVID-19 disease pathogenesis. Quantifying the kinetics of the secondary immune response from subsequent doses beyond the primary series, and understanding how dose-dependent immune waning kinetics vary as a function of age, sex, and various comorbidities, remains an important question. We study anti-spike IgG waning kinetics in 152 individuals who received an mRNA-based primary series and a subset of 137 individuals who then received a booster dose. We find the booster dose elicits a 71-84% increase in the median Anti-S half life over that of the primary series. We find the Anti-S half life for both primary series and booster doses drops as a function of increased year of age. However, we stress that although chronological age continues to be a good proxy for vaccine-induced humoral waning, immunosenescence is likely not the mechanism, rather, more likely the mechanism is related to the presence of noncommunicable diseases, which also accumulate with age, that affect immune regulation. We are able to independently reproduce recent observations that those with pre-existing asthma exhibit a stronger primary series humoral response to vaccination than compared to those that do not, and further find this result is sustained for the booster dose. Finally, via a single-variate KruskalWallis Test we find no difference between male and female decay kinetics, however, a multivariate approach utilizing Lasso regression for feature selection reveals a statistically significant (p-value<1×10−3), albeit small, bias in favour of longer-lasting humoral immunity amongst males.
Dynamics of bistable Néel domain walls under spin-orbit torque
Authors: Haltz Eloi , Franke Kévin J. A. , Marrows Christopher H.
Published: February 2024

Néel magnetic domain walls that are stabilized by achiral energy terms instead of the usual Dzyaloshinskii-Moriya interaction will be bistable, with the two possible chiral forms being degenerate. Here we focus on the theoretical study of the spin-orbit torque driven dynamics of such bistable Néel domain walls. We find that, for a given domain wall, two propagation directions along a nanowire are possible, depending on its initial state. These dynamics also exhibit complex dependence on the spin-orbit torque magnitude, leading to important transient regimes. Finally, a few ways are proposed for controlled or random reversal of the domain wall propagation direction. A robust analytical model which handles all the observed behaviors of such domain walls is developed and validated by comparing with numerical simulations. The dynamics obtained by this approach opens the way for using domain walls in information storage and processing devices in ways that are not possible with fixed chirality walls.

Published by the American Physical Society
2024
Virtual states in the coupled-channel problems with an improved complex scaling method
Authors: Chen Yan-Ke , Meng Lu , Lin Zi-Yang , Zhu Shi-Lin
Published: February 2024

We improve the complex scaling method (CSM) to obtain virtual states, which is challenging in the conventional CSM. Our approach solves the Schrödinger equation in momentum space as an eigenvalue problem by choosing flexible contours. It proves to be highly effective in identifying the poles across different Riemann sheets in multichannel scatterings. This approach is more straightforward and efficient than employing the Lippmann-Schwinger equation and using a root-finding algorithm to search for the zeros of the Fredholm determinant. This advancement significantly extends the capabilities of the CSM in accurately characterizing the virtual states in quantum systems.

Published by the American Physical Society
2024
Signatures of Fractional Statistics in Nonlinear Pump-Probe Spectroscopy
Authors: McGinley Max , Fava Michele , Parameswaran S. A.
Published: February 2024

We show that the presence of anyons in the excitation spectrum of a two-dimensional system can be inferred from nonlinear spectroscopic quantities. In particular, we consider pump-probe spectroscopy, where a sample is irradiated by two light pulses with an adjustable time delay between them. The relevant response coefficient exhibits a universal form that originates from the statistical phase acquired when anyons created by the first pulse braid around those created by the second. This behavior is shown to be qualitatively unchanged by nonuniversal physics including nonstatistical interactions and small nonzero temperatures. In magnetic systems, the signal of interest can be measured using currently available terahertz-domain probes, highlighting the potential usefulness of nonlinear spectroscopic techniques in the search for quantum spin liquids.

Published by the American Physical Society
2024
Women’s adoption of wearable health-monitoring technology: empirical evidence from a least developed country
Authors: Rahman Md. Shahinur , Hasan Najmul , Zhang Jing , Moral Iqbal Hossain , Hossain Gazi Md. Shakhawat
Published: February 2024

Purpose

Although wearable health-monitoring technology (WHMT) has become a stimulus for public health, women’s acceptance rate of this technology appears to be low. Thus, this study intends to investigate the factors affecting women’s adoption of WHMT.

Design/methodology/approach

The unified theory of acceptance and use of technology–2 model has been used in this study as a research framework that has been extended to include lifestyle and attitude. The proposed extended framework is validated using primary data (n = 314) collected from female respondents using a structured questionnaire; the partial least square-based structural equation modeling technique is subsequently used to test the proposed hypothesis.

Findings

The results show that effort expectancy, social influence, price value, habit, attitude and lifestyle have significant positive effects on women’s behavioral intention to use WHMT and accelerate actual usage behavior. Notably, effort expectancy and habit exhibit the largest impact on behavioral intention. However, performance expectancy, facilitating conditions and hedonic motivation are not significantly associated with behavioral intentions.

Practical implications

The findings of this study are important for healthcare practitioners and service providers to comprehensively understand the factors that affect women’s behavioral intentions in line with their actual usage behavior. This insight will help policymakers design viable strategies regarding WHMT to promote its sustainable usage in least developed countries.

Originality/value

This study contributes novelty by using an extended model that links women’s attitudes and lifestyles to their adoption of WHMT. This study also fills the gaps in the existing literature on women’s behavioral intentions in the context of WHMT by showing novel associations in the domain of WHMT uptake.
Monetary policy and overshooting of agricultural prices in China: in a supply chain perspective
Authors: Xiao Yitian , Dai Jiawu , Nuetah J. Alexander
Published: February 2024

Purpose

The purpose of this paper is to test the overshooting effects of monetary expansion on prices of agricultural products at farm production, processing and circulation stages in China, and to investigate the heterogeneity of the overshooting mechanisms in these three links.

Design/methodology/approach

Empirical results are obtained through the vector error correction model and the overshooting framework proposed by Saghaian et al. (2002b). Specifically, we first apply the Dickey–Fuller generalized least squares (DF-GLS) method to test the stationarity of the key variables, and then use the Johansen’s (1991) method to conduct the cointegration test. Finally, the vector error correction model is employed to examine the overshooting hypotheses in the three stages of China’s agricultural sector.

Findings

Empirical results indicate that overshooting of prices relative to monetary expansion in China’s agricultural sector is a common phenomenon, but with significant heterogeneity. Firstly, at the stage of agricultural production, the overshooting degree and restoration rate of material price are greater than those of agricultural products price. Secondly, at the processing stage of agricultural products, both the purchase price of agricultural products and industrial producer price have an overshooting effect, but the overshooting effect of the former is more significant than the latter. Thirdly, at the circulation stage of agricultural products, the overshooting coefficient of the wholesale price index of agricultural products is the most significant, while that of the retail and purchase price of agricultural products is not significant.

Originality/value

The paper contributes to proposing a comprehensive framework on testing the overshooting effects for three main stages of agricultural sector in China and empirically investigating the heterogeneity of the overshooting mechanisms in different stages with time series methods.
The moderating role of duality split on the relationship between CEO narcissism and earnings management
Authors: Azevedo Yuri Gomes Paiva , Silva Mariana Câmara Gomes e , Nakao Silvio Hiroshi
Published: February 2024

Purpose

The purpose of this study is to examine the moderating effect of an exogenous corporate governance shock that curbs Chief Executive Officers’ (CEOs) power on the relationship between CEO narcissism and earnings management practices.

Design/methodology/approach

The authors performed a quasi-experiment using a differences-in-differences approach to examine Brazil’s duality split regulatory change on 101 Brazilian public firms during the period 2010–2022.

Findings

The main findings indicate that the introduction of duality split curtails the positive influence of CEO narcissism on earnings management, suggesting that this corporate governance regulation may act as a complementary corporate governance mechanism in mitigating the negative consequences of powerful narcissistic CEOs. Further robustness checks indicate that the results remain consistent after using entropy balancing and alternative measures of CEO narcissism.

Practical implications

In emerging markets, where governance systems are frequently perceived as less than optimal, policymakers and regulatory authorities can draw insights from this enforcement to shape governance systems, reducing CEO power and, consequently, improving the quality of financial reporting.

Originality/value

To the best of the authors’ knowledge, this is the first study to examine whether a duality split mitigates the influence of CEO narcissism on earnings management. Thus, this study contributes to the corporate governance literature that calls for research on the effectiveness of external corporate governance mechanisms in emerging markets as well as the CEO narcissism literature that calls for research on moderating factors that could curtail negative consequences of narcissistic CEO behavior.
Contractors’ carbon reduction behaviour: UK construction professionals’ perspective
Authors: Arogundade Suhaib , Dulaimi Mohammed , Ajayi Saheed , Saad Ali
Published: February 2024

Purpose

The decisions of contractors could impact the reduction of construction carbon footprint. These decisions are linked to the belief of contractors which equally affects how they behave while delivering projects. This study aims to investigate the behavioural tendencies of contractors that could lead to carbon minimisation during the execution of construction projects.

Design/methodology/approach

An industry survey was performed amongst 41 UK construction professionals. Spearman’s correlation and factor analysis were used to analyse the data.

Findings

The result of the Spearman’s correlation gave rise to 14 contractors’ carbon reduction behaviour (CCRB) variables and their factor analysis yielded two distinct factors, namely, contractors’ consummate carbon reduction behaviour and contractors’ pragmatic carbon reduction behaviour. The findings suggest that in the UK, contractors are willing to take voluntary practical steps to decrease the carbon footprint of construction projects.

Practical implications

This finding might be unexpected to construction stakeholders, especially construction clients who may believe that infusing strict carbon reduction obligations in contracts is sufficient in nudging contractors to lessen the carbon impact of projects.

Originality/value

The study attempted to quantitatively derive CCRB, thereby extending the breadth of knowledge in the construction carbon reduction domain.
Microenterprise performance amidst environmental turbulence and resource scarcity: an integrated capital approach
Authors: DelVecchio Micah , Ofori-Dankwa Joseph , Darkwah Akosua K.
Published: February 2024

Purpose

Microenterprises in emerging economies are known to operate in turbulent and resource-scarce environments. We test our hypothesis that a more comprehensive “Integrated Capital-Based Model” (ICBM) is needed when explaining the performance of microenterprises in such an environment. The model combines traditionally researched financial, human and social capital with more recently emphasized psychological and cognitive capital, providing greater explanatory power than models using only the traditional types of capital.

Design/methodology/approach

We use a pooled linear regression to analyze an existing survey of more than 900 independent business owners who were interviewed seven times between 2008 and 2012 in the Accra and Tema marketplaces in Ghana. We measure the performance of microenterprises using three dependent variables (revenue, profits, and productivity). We contrast the explanatory power of ICBM models against the more traditional models.

Findings

The ICBM has significantly higher levels of explanatory power over the traditional models in examining the performance of these microenterprises. These results highlight the importance of psychological and cognitive capital in emerging economies.

Research limitations/implications

We advocate for a more comprehensive view of capital as shown in our ICBM. However, the data were gathered only in an urban setting, which limits the generalizability to rural parts of emerging economies.

Practical implications

These findings suggest the utility of government and appropriate agencies finding ways to enhance the level of psychological and cognitive capital of microenterprise owners.

Originality/value

This paper's originality stems from hypothesizing and empirically confirming the higher predictive efficacy of ICBM against more traditionally researched capital sources.
Assessing supply chain management’s impact on new product performance: the mediating role of marketing innovation orientation during COVID-19
Authors: Dahan Gavriel , Levi-Bliech Michal
Published: February 2024

Purpose

The main purpose of this study is to examine the influence of two characteristics of supply chain management (SCM) (resilience and integration) on new product performance (NPP) via the mediation of marketing innovation orientation.

Design/methodology/approach

This study was designed by the quantitative method, and the research model was developed based on the resource-based view (RBV) theory of 211 managers from Israeli firms using SmartPls3 software.

Findings

The main finding that emerges from this study is that marketing innovation orientation serves as a full mediator in the relationship between supply chain resilience (SCR) and NPP as well as in the relationship between supply chain integration (SCI) and NPP. Thus, companies that wish to achieve a competitive advantage over their rivals should improve and strengthen their marketing innovation orientation. By doing so, they enhance the relationship between SCM and NPP.

Practical implications

The findings provide an applicable guideline for marketing managers. Managers should be ready to adapt to customers’ demands, environmental changes and, most importantly, disruptive events in a dynamic environment.

Originality/value

The current study sheds light on the mechanism for NPP via integrating suppliers, customers and the organization. So, managers should adopt SCR and integration to strengthen their marketing innovation orientation in order to achieve NPP.
Smart Chair Development using ESP32 Microcontroller – A Preliminary Study
Authors: Mohd Shahriman Muhammad Norman Nurhakim , Tan Xi Ning , Mahmud Rasid Mahmud Thaqif , Yusri Batrisyia Inanda Sari , Abdul-Kadir Nurul Ashikin , Mat Safri Norlaili
Published: February 2024

In response to the coronavirus disease 2019 (COVID-19) pandemic, the shift to online delivery mode for most teaching faculties has increased the risk of chronic back and neck pain for students and teachers. While short-term adjustments like working from the couch or using an uncomfortable kitchen chair might seem tolerable for working adults or university students, these habits can have detrimental long-term impacts on body and health. Although the pandemic situation has improved, and people are gradually returning to physical workplaces and classrooms, many individuals still spend a significant amount of time sitting in front of screens for work and other activities. This explains why 70% of adults in Malaysia have experienced back and neck pain at least once in their lives. This pre-study proposes a smart chair equipped with sensors that alert users to correct their sitting posture and take screen breaks for stretching, potentially reducing the risk of future muscle aches and pain.
Tissue Engineering for Cardiovascular Regeneration: Brief Review on Scaffold Fabrication
Authors: Parveen Malick Thasleema , Vangetaraman Kugambikai , Saidin Syafiqah , Nasution Ahmad Kafrawi
Published: February 2024

Tissue engineering is the combination of engineering and fundamental sciences to develop an artificial organ that derived from the tissue human sources. It involves the construction of three main pillars include cell sources, scaffold materials and biological factors. These three important elements are necessary to be incorporated and integrated well, to construct a functional artificial tissue engineering product. Few applications can be associated with the expansion of tissue engineering where cardiovascular regeneration is one of the targets of tissue engineering. Among the fabrication techniques, electrospinning, three-dimensional printing, molding and decellularization, are four engineering methods that are commonly used in fabricating scaffolds for cardiovascular tissue engineering. One of the purposes of the emerging of cardiovascular tissue engineering is the limitation of current commercialized patches or membranes that often cause post-complications following the cardiovascular treatments. This review paper covering a brief introduction on the tissue engineering for cardiovascular regeneration, focusing on the scaffold fabrication.
Enhanced Irradiance Levels using Synergistically Engineered Monochromatic Wavelength Ultraviolet-C Arrays Configuration
Authors: Sheikh Jahanzeb , Saidin Dr. Syafiqah , Ahmed Malik Sameen , Tan Tian Swee , Chua Lee Suan , Mohamed Ahmed Asim Ahmed Ibrahim , Kun Ma , Tiong Matthias Foh Thye , Leong Kah Meng
Published: February 2024

Contamination in healthcare environment poses risk of microbial transmission to healthy people. Recently, conventional ultraviolet (UV) technologies, particularly low-pressure mercury lamps have caught researcher’s attention for disinfection. Nonetheless, drawbacks such as hazardous components, limited lifespan, warm-up time, maintenance and fragility have driven researchers to delve into light emitting diode (LED) technologies as an appealing alternative. However, due to the diminishing intensity exhibited by LEDs over extended distances, prior studies primarily focused on short-distance investigations. Consequently, the phenomenon remained insufficient owing to the limited exploration in this field. Furthermore, frequently investigated LEDs in ambient settings, potentially created a gap in completely understanding the capability for irradiance attainability. Hence, this study aimed to overcome this limitation by evaluating the effectiveness of UV-C LEDs with synergistic arrangements within an enclosed chamber, offering optimum settings for examining irradiance performance. The analyzed recorded data aimed to identify trends in emission performance over different distances (5 to 60 cm), providing insights into how the arrangement of LEDs could influence irradiance output. The study unveiled that the synergistic effects of 6, 8, and 10-LED, when strategically engineered, significantly contributed to enhanced intensity. Notably, 10-SEMW LEDs exhibited a remarkable ability to maintain significant irradiance levels across extended distances. This was evident in the range between 0.037 and 0.016 mW.cm⁻² observed at 5 and 60 cm, respectively. In conclusion, the findings stress the importance of strategically arranging LEDs in a synergistic configuration to achieve optimal irradiance levels across a diverse range of spatial parameters for effective long-range disinfection.
Prediction of State of Charge for Lead-Acid Battery Based on LSTM-Attention and LightGBM
Authors: Shen Yindong , Ge Yaru
Published: February 2024

Accurately estimating the state of charge (SOC) of batteries is crucial for the objective of extending battery life and enhancing power supply reliability. Currently, machine learning methods are commonly used to predict the SOC of batteries, however, their accuracy in capturing the sequential nature of battery charging and discharging is insufficient. To address the problem of the SOC prediction, a deep learning model that employs long short-term memory (LSTM) with Attention mechanism is proposed. The LSTM model is designed to connect the current SOC with historical time data and to extract multidimensional features from groups of batteries. Additionally, introducing the Attention mechanism allows for the model to prioritize key information while disregarding insignificant data. This work utilizes two different approaches to the multi-cell case and the single-cell case for several reasons. Considering that the failure of a single cell can affect the entire group of batteries, the SOC prediction models for individual batteries need not take a long training time. Thus, the LightGBM model is developed to predict the SOC of a single battery whose training speed surpasses that of the deep learning model and has superior prediction accuracy and greater speed when employed with small-scale data, error within 3%. Conversely, the LSTM-Attention model yields higher prediction accuracy when processing large-scale datasets, error within 5%. Two models are proposed: one for predicting the SOC of groups of batteries and another for a single battery.
Finite Element Method-Based Dynamic Modeling Framework for Flexible Continuum Manipulators
Authors: Modassir Firdaus Md , Dilip Paranjape Omkar , Vadali Madhu
Published: February 2024

Flexible continuum manipulators (FCMs) are gaining importance because of their maneuverability and pliability in confined and complex spaces, where rigid link manipulators underperform. However, the dynamic behavior and control of the FCM are quite challenging due to its complex nonlinear behavior. In this study, a finite element-based dynamic model framework is derived that accounts for the geometric nonlinearities and inertial effects. An experimental setup of tendon-driven FCM, consisting of a flexible backbone, is developed to validate the model. The modal analysis of the model is in agreement with the analytical solutions, with less than 10% error. The model is also validated for various loading conditions on the tip-actuated tendon-driven FCM. The steady-state tip position predictions are within 15% of the ground truth.
A Physics-Informed Neural Operator for the Simulation of Surface Waves
Authors: Mathias Marlon S. , Netto Caio F. D. , Moreno Felipe M. , Coelho Jefferson F. , de Freitas Lucas P. , de Barros Marcel R. , de Mello Pedro C. , Dottori Marcelo , Cozman Fábio G. , Costa Anna H. R. , Nogueira Junior Alberto C. , Gomi Edson S. , Tannuri Eduardo A.
Published: February 2024

We develop and implement a neural operator (NOp) to predict the evolution of waves on the surface of water. The NOp uses a graph neural network (GNN) to connect randomly sampled points on the water surface and exchange information between them to make the prediction. Our main contribution is adding physical knowledge to the implementation, which allows the model to be more general and able to be used in domains of different geometries with no retraining. Our implementation also takes advantage of the fact that the governing equations are independent of rotation and translation to make training easier. In this work, the model is trained with data from a single domain with fixed dimensions and evaluated in domains of different dimensions with little impact to performance.
Genome analysis and hyphal movement characterization of the hitchhiker endohyphal
Enterobacter
sp. from
Rhizoctonia solani
Authors: Zhang Peiqi , Huguet-Tapia Jose , Peng Zhao , Liu Sanzhen , Obasa Ken , Block Anna K. , White Frank F.
Published: February 2024

The genome characterization and comparative genomics analysis of
Enterobacter
sp. Crenshaw provided the foundation and resources for a better understanding of the ecology and evolution of this endohyphal bacteria in the rhizosphere. The ability to produce indole-3-acetic acid and phenylacetic acid may provide new angles to study the impact of phytohormones during the plant-pathogen interactions. The hitchhiking behavior of the bacterium on a diverse group of fungi, while inhibiting the growth of some others, revealed new areas of bacterial-fungal signaling and interaction, which have yet to be explored.
Beyond schistosomiasis: unraveling co-infections and altered immunity
Authors: Perera Dilhan J. , Koger-Pease Cal , Paulini Kayla , Daoudi Mohamed , Ndao Momar
Published: February 2024

Schistosomiasis is a neglected tropical disease caused by the helminth
Schistosoma
spp. and has the second highest global impact of all parasites.
Schistosoma
are transmitted through contact with contaminated fresh water predominantly in Africa, Asia, the Middle East, and South America. Due to the widespread prevalence of
Schistosoma
, co-infection with other infectious agents is common but often poorly described. Herein, we review recent literature describing the impact of
Schistosoma
co-infection between species and
Schistosoma
co-infection with blood-borne protozoa, soil-transmitted helminths, various intestinal protozoa,
Mycobacterium
,
Salmonella
, various urinary tract infection-causing agents, and viral pathogens. In each case, disease severity and, of particular interest, the immune landscape, are altered as a consequence of co-infection. Understanding the impact of schistosomiasis co-infections will be important when considering treatment strategies and vaccine development moving forward.
A dual-plasmid CRISPR/Cas9-based method for rapid and efficient genetic disruption in
Mycobacterium abscessus
Authors: Neo Donavan Marcus , Clatworthy Anne E. , Hung Deborah T.
Published: February 2024

Mycobacterium abscessus
is increasingly recognized for causing infections that are notoriously difficult to treat, owing to its large arsenal of intrinsic antibiotic resistance mechanisms. Tools for the genetic manipulation of the pathogen are critical for enabling a better understanding of
M. abscessus
biology, pathogenesis, and antibiotic resistance mechanisms. However, existing methods are largely recombination-based, which are relatively inefficient. Meanwhile, CRISPR/Cas9 has revolutionized the field of genome editing including its recent adaptation for use in mycobacteria. In this study, we report a streamlined and efficient method for rapid genetic disruptions in
M. abscessus
. Harnessing the CRISPR1 loci from
Streptococcus thermophilus
, we have developed a dual-plasmid workflow that introduces Cas9 and sgRNA cassettes in separate steps but requires no other additional factors to engineer mutations in single genes or multiple genes simultaneously or sequentially using multiple targeting sgRNAs. Importantly, the efficiency of mutant generation is several orders of magnitude higher than reported for homologous recombination-based methods. This work, thus, reports the first application of CRISPR/Cas9 for gene editing in
M. abscessus
and is an important tool in the arsenal for the genetic manipulation of this human pathogen.

IMPORTANCE

Mycobacterium abscessus
is an opportunistic pathogen of increasing clinical importance due to its poor clinical outcomes and limited treatment options. Drug discovery and development in this highly antibiotic-resistant species will require further understanding of
M. abscessus
biology, pathogenesis, and antibiotic resistance mechanisms. However, existing methods for facile genetic engineering are relatively inefficient. This study reports on the first application of CRISPR/Cas9 for gene editing in
M. abscessus
using a dual-plasmid workflow. We establish that our method is easily programmable, efficient, and versatile for genetic disruptions in
M. abscessus
. This is a critical advancement to facilitating targeted gene function studies in this emerging pathogen.
Multicenter study to assess the use of BL-DetecTool for the detection of CTX-M-type ESBLs and carbapenemases directly from clinical specimens
Authors: Fernandez-Pittol Mariana , Bosch Jordi , Ballesté-Delpierre Clara , Gonzalez Camille , Vasilakopoulou Alexandra , Berbel Dàmaris , Riccobono Eleonora , Gatermann Sören , Kamotsay Katalin , Reissier Sophie , Szabo Dora , Aszalos Albert Zoltan , Francius Laura , Volland Hervé , Stankov-Pugès Milovan , Rosenmöller Magda , Naas Thierry , Vila Jordi
Published: February 2024

Antimicrobial resistance (AMR) is one of the major public health problems worldwide. Multiple strategies have been put in place to address this problem. One of them is the rapid detection of the mechanisms of resistance, such as extended-spectrum beta-lactamases (ESBLs) and/or carbapenemases. We conducted a multicenter study that included nine European centers for the assessment of prototypes of a novel lateral flow immunoassay-based device (BL-DetecTool) for a rapid detection of ESBL (NG-Test CTX-M-MULTI DetecTool) and/or carbapenemases (NG-Test CARBA 5 DetecTool) from
Enterobacterales
and
Pseudomonas aeruginosa
in positive urine, positive blood cultures, and rectal swabs. We performed a prospective analysis between January 2021 and June 2022, including overall 22,010 samples. Based on each hospital information, the sensitivity to detect CTX-M was 84%–100%, 90.9%–100%, and 75%–100% for urine, positive blood cultures, and enriched rectal swabs, respectively. On the other hand, the sensitivity to detect carbapenemases was 42.8%–100%, 75%–100%, and 66.6%–100% for urine, positive blood cultures, and enriched rectal swab, respectively. BL-DetecTool allows a rapid and reliable detection of ESBL and carbapenemases directly from urine, positive blood cultures, or enriched rectal swabs, being an easy technique to implement in the workflow of clinical microbiology laboratories.

IMPORTANCE

The assessed rapid assay to detect CTX-M beta-lactamases and carbapenemases directly from clinical samples can favor in the rapid detection of these mechanisms of resistance and hence the administration of a more adequate antimicrobial treatment.
Unraveling the dynamics of hepatitis C virus adaptive mutations and their impact on antiviral responses in primary human hepatocytes
Authors: Frericks Nicola , Brown Richard J. P. , Reinecke Birthe M. , Herrmann Maike , Brüggemann Yannick , Todt Daniel , Miskey Csaba , Vondran Florian W. R. , Steinmann Eike , Pietschmann Thomas , Sheldon Julie
Published: February 2024

Hepatitis C virus (HCV) infection progresses to chronicity in the majority of infected individuals. Its high intra-host genetic variability enables HCV to evade the continuous selection pressure exerted by the host, contributing to persistent infection. Utilizing a cell culture-adapted HCV population (p100pop) which exhibits increased replicative capacity in various liver cell lines, this study investigated virus and host determinants that underlie enhanced viral fitness. Characterization of a panel of molecular p100 clones revealed that cell culture adaptive mutations optimize a range of virus-host interactions, resulting in expanded cell tropism, altered dependence on the cellular co-factor micro-RNA 122 and increased rates of virus spread. On the host side, comparative transcriptional profiling of hepatoma cells infected either with p100pop or its progenitor virus revealed that enhanced replicative fitness correlated with activation of endoplasmic reticulum stress signaling and the unfolded protein response. In contrast, infection of primary human hepatocytes with p100pop led to a mild attenuation of virion production which correlated with a greater induction of cell-intrinsic antiviral defense responses. In summary, long-term passage experiments in cells where selective pressure from innate immunity is lacking improves multiple virus-host interactions, enhancing HCV replicative fitness. However, this study further indicates that HCV has evolved to replicate at low levels in primary human hepatocytes to minimize innate immune activation, highlighting that an optimal balance between replicative fitness and innate immune induction is key to establish persistence.

IMPORTANCE

Hepatitis C virus (HCV) infection remains a global health burden with 58 million people currently chronically infected. However, the detailed molecular mechanisms that underly persistence are incompletely defined. We utilized a long-term cell culture-adapted HCV, exhibiting enhanced replicative fitness in different human liver cell lines, in order to identify molecular principles by which HCV optimizes its replication fitness. Our experimental data revealed that cell culture adaptive mutations confer changes in the host response and usage of various host factors. The latter allows functional flexibility at different stages of the viral replication cycle. However, increased replicative fitness resulted in an increased activation of the innate immune system, which likely poses boundary for functional variation in authentic hepatocytes, explaining the observed attenuation of the adapted virus population in primary hepatocytes.
Assemblages of rhizospheric and root endospheric mycobiota and their ecological associations with functional traits of rice
Authors: Guo Junjie , Ning Huiling , Li Yong , Xu Qicheng , Shen Qirong , Ling Ning , Guo Shiwei
Published: February 2024

The soil-root interface harbors complex fungal communities that play vital roles in the fitness of host plants. However, little is known about the assembly rules and potential functions of rhizospheric and endospheric mycobiota. A greenhouse experiment was conducted to explore the fungal communities inhabiting the rhizosphere and roots of 87 rice cultivars at the tillering stage via amplicon sequencing of the fungal internal transcribed spacer 1 region. The potential relationships between these communities and host plant functional traits were also investigated using Procrustes analysis, generalized additive model fitting, and correlation analysis. The fungal microbiota exhibited greater richness, higher diversity, and lower structural variability in the rhizosphere than in the root endosphere. Compared with the root endosphere, the rhizosphere supported a larger coabundance network, with greater connectivity and stronger cohesion. Null model-based analyses revealed that dispersal limitation was primarily responsible for rhizosphere fungal community assembly, while ecological drift was the dominant process in the root endosphere. The community composition of fungi in the rhizosphere was shown to be more related to plant functional traits, such as the root/whole plant biomass, root:shoot biomass ratio, root/shoot nitrogen (N) content, and root/shoot/whole plant N accumulation, than to that in the root endosphere. Overall, at the early stage of rice growth, diverse and complex rhizospheric fungal communities are shaped by stochastic-based processes and exhibit stronger associations with plant functional traits.

IMPORTANCE

The assembly processes and functions of root-associated mycobiota are among the most fascinating yet elusive topics in microbial ecology. Our results revealed that stochastic forces (dispersal limitation or ecological drift) act on fungal community assembly in both the rice rhizosphere and root endosphere at the early stage of plant growth. In addition, high covariations between the rhizosphere fungal community compositions and plant functional trait profiles were clearly demonstrated in the present study. This work provides empirical evidence of the root-associated fungal assembly principles and ecological relationships of plant functional traits with rhizospheric and root endospheric mycobiota, thereby potentially providing novel perspectives for enhancing plant performance.
Verification of a method using magnetic bead enrichment and nucleic acid extraction to improve the molecular detection of bacterial contamination in blood components
Authors: Na Byungjoon , Lee Jinyeop , Chang Ho Eun , Park Eunseon , Park Sojin , Lee Jiyoung , Oh Sujin , Shin Dong Woo , Hong Yun Ji , Park Kyoung Un
Published: February 2024

Bacterial contamination of blood products poses a significant risk in transfusion medicine. Platelets are particularly vulnerable to bacterial growth because they must be stored at room temperature with constant agitation for >5 days. The limitations of bacterial detection using conventional methods, such as blood cultures and lateral flow assays, include the long detection times, low sensitivity, and the requirement for substantial volumes of blood components. To address these limitations, we assessed the performance of a bacterial enrichment technique using antibiotic-conjugated magnetic nanobeads (AcMNBs) and real-time PCR for the detection of bacterial contamination in plasma. AcMNBs successfully captured >80% of four bacterial strains, including
Staphylococcus aureus
,
Bacillus cereus
,
Escherichia coli
, and
Klebsiella pneumoniae
, in both plasma and phosphate-buffered saline. After 24-h incubation with bacterial enrichment,
S. aureus
and
B. cereus
were each detected at 10
1
CFU/mL in all trials (5/5),
E. coli
at 10
1
CFU/mL in 1/5 trials, and
K. pneumoniae
at 10² CFU/mL in 4/5 trials. Additionally, without incubation, the improvement was also achieved in samples with bacterial enrichment,
S. aureus
at 10² CFU/mL and
B. cereus
at 10
1
CFU/mL in 1/5 trials each,
E. coli
at 10³ CFU/mL in 3/5 trials, and
K. pneumoniae
at 10¹ CFU/mL in 2/5 trials. Overall, the findings from this study strongly support the superiority of bacterial enrichment in detecting low-level bacterial contamination in plasma when employing AcMNBs and PCR.

IMPORTANCE

The study presents a
break
through
approach to detect bacterial contamination in plasma, a critical concern in transfusion medicine. Traditional methods, such as blood cultures and lateral flow assays, are hampered by slow detection times, low sensitivity, and the need for large blood sample volumes. Our research introduces a novel technique using antibiotic-conjugated magnetic nanobeads combined with real-time PCR, enhancing the detection of bacteria in blood products, especially platelets. This method has shown exceptional efficiency in identifying even low levels of four different species of bacteria in plasma. The ability to detect bacterial contamination rapidly and accurately is vital for ensuring the safety of blood transfusions and can significantly reduce the risk of infections transmitted through blood products. This advancement is a pivotal step in improving patient outcomes and elevating the standards of care in transfusion medicine.
Isolated intramuscular cysticercosis of the forearm masquerading as malignancy
Authors: Goel Archit , Kapatia Gargi , Mir Mohd Altaf , Rana Manjit Kaur
Published: February 2024

A woman in her mid-20s presented to an Indian tertiary care hospital with pain in her left forearm. Extensive initial investigations led to a suspected diagnosis of a peripheral nerve sheath tumour; however, the pathological investigation of the excised tumour mass revealed it to be a case of isolated intramuscular cysticercosis in the forearm. Treatment for cysticercosis was commenced and the patient made a full recovery. Isolated intramuscular cysticercosis without the involvement of other organs is a rare presentation and has only been reported in a handful of case reports. We suggest that isolated intramuscular cysticercosis be considered a differential diagnosis in patients with isolated pain in their muscles and with no other symptoms, in patients with a presentation of solitary swelling and in patients at risk of parasitic infection. In addition, we emphasise the importance of histopathological examination due to the varied presentation of cysts.
Hypercalcaemia of malignancy: a case of vitamin-D-mediated hypercalcaemia in lymphoma
Authors: Mehta Kanchi , Awan Maham , Devlin Shannon , Jassal Simerjot Kaur
Published: February 2024

Hypercalcaemia of malignancy (HCM) is a paraneoplastic syndrome that often portends a poor prognosis. We present an extremely rare (<1%) case of HCM due to extrarenal calcitriol (1,25-(OH)2D) production in a patient with splenic marginal zone lymphoma. A man in his 80s presented with a 3-week history of fatigue, unsteadiness and abdominal pain, and new findings of anaemia, kidney injury and hypercalcaemia. Laboratory evaluation, bone marrow biopsy and positron emission tomography/computed tomography (PET/CT) confirmed the diagnosis of splenic marginal zone lymphoma which produced calcitriol (1,25-(OH)2D3), causing the patient’s hypercalcaemia.
Sentinel ear bleed as a presenting sign for carotid artery blowout due to aspergillus abscess in parapharyngeal space in an immunocompetent infant
Authors: Rajpal Neha , Saxena Romit , Meher Ravi , Dabas Aashima
Published: February 2024

Parapharyngeal abscesses leading to complications, although rare after the advent of antibiotics, can lead to serious complications. One such complication is carotid erosion that can lead to a potentially fatal carotid artery blowout. We report a case of a previously healthy infant who presented with fever, ear bleed and progressively increasing swelling in the right side of his neck that led to airway compromise. The child required immediate securing of the airway at presentation. Imaging revealed lobulated abscess with multiple bleeding points eroding the carotid vessels, along with internal jugular venous thrombus. Surgical exploration was done and abscess debulked. Histopathology revealed aspergillus, which was treated with antifungals. He was discharged on oral warfarin after 40 days of hospital stay and remains well on follow-up. Sentinel ear bleed warrants close observation for possibility of carotid artery blowout in children with parapharyngeal abscesses.