bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences in thick filament activation in fast rodent skeletal muscle and slow porcine cardiac muscle
Authors: Zhao Jing , Qi Lin , Yuan Shengyao , Irving Thomas C. , Ma Weikang 
Published: May 2024

AbstractThere is a growing appreciation that regulation of muscle contraction requires both thin filament and thick filament activation in order to fully activate the sarcomere. The prevailing mechano‐sensing model for thick filament activation was derived from experiments on fast‐twitch muscle. We address the question whether, or to what extent, this mechanism can be extrapolated to the slow muscle in the hearts of large mammals, including humans. We investigated the similarities and differences in structural signatures of thick filament activation in porcine myocardium as compared to fast rat extensor digitorum longus (EDL) skeletal muscle under relaxed conditions and sub‐maximal contraction using small angle X‐ray diffraction. Thick and thin filaments were found to adopt different structural configurations under relaxing conditions, and myosin heads showed different changes in configuration upon sub‐maximal activation, when comparing the two muscle types. Titin was found to have an X‐ray diffraction signature distinct from those of the overall thick filament backbone, and its spacing change appeared to be positively correlated to the force exerted on the thick filament. Structural changes in fast EDL muscle were found to be consistent with the mechano‐sensing model. In porcine myocardium, however, the structural basis of mechano‐sensing is blunted suggesting the need for additional activation mechanism(s) in slow cardiac muscle. These differences in thick filament regulation can be related to their different physiological roles where fast muscle is optimized for rapid, burst‐like, contractions, and the slow cardiac muscle in large mammalian hearts adopts a more finely tuned, graded response to allow for their substantial functional reserve.
imageKey points
Both thin filament and thick filament activation are required to fully activate the sarcomere.
Thick and thin filaments adopt different structural configurations under relaxing conditions, and myosin heads show different changes in configuration upon sub‐maximal activation in fast extensor digitorum longus muscle and slow porcine cardiac muscle.
Titin has an X‐ray diffraction signature distinct from those of the overall thick filament backbone and this titin reflection spacing change appeared to be directly proportional to the force exerted on the thick filament.
Mechano‐sensing is blunted in porcine myocardium suggesting the need for additional activation mechanism(s) in slow cardiac muscle.
Fast skeletal muscle is optimized for rapid, burst‐like contractions, and the slow cardiac muscle in large mammalian hearts adopts a more finely tuned graded response to allow for their substantial functional reserve.
Functional consequences of modification of the photosystem I/photosystem II ratio in the cyanobacterium
Synechocystis
sp. PCC 6803
Authors: Moore Vicki , Vermaas Wim 
Published: May 2024

ABSTRACT

The stoichiometry of photosystem II (PSII) and photosystem I (PSI) varies between photoautotrophic organisms. The cyanobacterium
Synechocystis
sp. PCC 6803 maintains two- to fivefold more PSI than PSII reaction center complexes, and we sought to modify this stoichiometry by changing the promoter region of the
psaAB
operon. We thus generated mutants with varied
psaAB
expression, ranging from ~3% to almost 200% of the wild-type transcript level, but all showing a reduction in PSI levels, relative to wild type, suggesting a role of the
psaAB
promoter region in translational regulation. Mutants with 25%–70% of wild-type PSI levels were photoautotrophic, with whole-chain oxygen evolution rates on a per-cell basis comparable to that of wild type. In contrast, mutant strains with <10% of the wild-type level of PSI were obligate photoheterotrophs. Variable fluorescence yields of all mutants were much higher than those of wild type, indicating that the PSI content is localized differently than in wild type, with less transfer of PSII-absorbed energy to PSI. Strains with less PSI saturate at a higher light intensity, enhancing productivity at higher light intensities. This is similar to what is found in mutants with reduced antennae. With 3-(3,4-dichlorophenyl)-1,1-dimethylurea present, P700
+
re-reduction kinetics in the mutants were slower than in wild type, consistent with the notion that there is less cyclic electron transport if less PSI is present. Overall, strains with a reduction in PSI content displayed surprisingly vigorous growth and linear electron transport.

IMPORTANCE

Consequences of reduction in photosystem I content were investigated in the cyanobacterium
Synechocystis
sp. PCC 6803 where photosystem I far exceeds the number of photosystem II complexes. Strains with less photosystem I displayed less cyclic electron transport, grew more slowly at lower light intensity and needed more light for saturation but were surprisingly normal in their whole-chain electron transport rates, implying that a significant fraction of photosystem I is dispensable for linear electron transport in cyanobacteria. These strains with reduced photosystem I levels may have biotechnological relevance as they grow well at higher light intensities.
Universal digital high-resolution melting for the detection of pulmonary mold infections
Authors: Goshia Tyler , Aralar April , Wiederhold Nathan , Jenks Jeffrey D. , Mehta Sanjay R. , Karmakar Aprajita , E.S. Monish , Sharma Ankit , Sun Haoxiang , Kebadireng Refilwe , White P. Lewis , Sinha Mridu , Hoenigl Martin , Fraley Stephanie I. 
Published: May 2024

ABSTRACT

Invasive mold infections (IMIs) are associated with high morbidity, particularly in immunocompromised patients, with mortality rates between 40% and 80%. Early initiation of appropriate antifungal therapy can substantially improve outcomes, yet early diagnosis remains difficult to establish and often requires multidisciplinary teams evaluating clinical and radiological findings plus supportive mycological findings. Universal digital high-resolution melting (U-dHRM) analysis may enable rapid and robust diagnoses of IMI. A universal fungal assay was developed for U-dHRM and used to generate a database of melt curve signatures for 19 clinically relevant fungal pathogens. A machine learning algorithm (ML) was trained to automatically classify these pathogen curves and detect novel melt curves. Performance was assessed on 73 clinical bronchoalveolar lavage samples from patients suspected of IMI. Novel curves were identified by micropipetting U-dHRM reactions and Sanger sequencing amplicons. U-dHRM achieved 97% overall fungal organism identification accuracy and a turnaround time of ~4 hrs. U-dHRM detected pathogenic molds (
Aspergillus
,
Mucorales
,
Lomentospora
, and
Fusarium
) in 73% of 30 samples classified as IMI, including mixed infections. Specificity was optimized by requiring the number of pathogenic mold curves detected in a sample to be
>
8 and a sample volume to be 1 mL, which resulted in 100% specificity in 21 at-risk patients without IMI. U-dHRM showed promise as a separate or combination diagnostic approach to standard mycological tests. U-dHRM’s speed, ability to simultaneously identify and quantify clinically relevant mold pathogens in polymicrobial samples, and detect emerging opportunistic pathogens may aid treatment decisions, improving patient outcomes.

IMPORTANCE
Improvements in diagnostics for invasive mold infections are urgently needed. This work presents a new molecular detection approach that addresses technical and workflow challenges to provide fast pathogen detection, identification, and quantification that could inform treatment to improve patient outcomes.
Triple lysine and nucleosome-binding motifs of the viral IE19 protein are required for human cytomegalovirus S-phase infections
Authors: Maliano Minor R. , Yetming Kristen D. , Kalejta Robert F. 
Published: May 2024

ABSTRACT

Herpesvirus genomes are maintained as extrachromosomal plasmids within the nuclei of infected cells. Some herpesviruses persist within dividing cells, putting the viral genome at risk of being lost to the cytoplasm during mitosis because karyokinesis (nuclear division) requires nuclear envelope breakdown. Oncogenic herpesviruses (and papillomaviruses) avoid genome loss during mitosis by tethering their genomes to cellular chromosomes, thereby ensuring viral genome uptake into newly formed nuclei. These viruses use viral proteins with DNA- and chromatin-binding capabilities to physically link viral and cellular genomes together in a process called tethering. The known viral tethering proteins of human papillomavirus (E2), Epstein-Barr virus (EBNA1), and Kaposi’s sarcoma-associated herpesvirus (LANA) each contain two independent domains required for genome tethering, one that binds sequence specifically to the viral genome and another that binds to cellular chromatin. This latter domain is called a chromatin tethering domain (CTD). The human cytomegalovirus UL123 gene encodes a CTD that is required for the virus to productively infect dividing fibroblast cells within the S phase of the cell cycle, presumably by tethering the viral genome to cellular chromosomes during mitosis. The CTD-containing UL123 gene product that supports S-phase infections is the IE19 protein. Here, we define two motifs in IE19 required for S-phase infections: an N-terminal triple lysine motif and a C-terminal nucleosome-binding motif within the CTD.

IMPORTANCE
The IE19 protein encoded by human cytomegalovirus (HCMV) is required for S-phase infection of dividing cells, likely because it tethers the viral genome to cellular chromosomes, thereby allowing them to survive mitosis. The mechanism through which IE19 tethers viral genomes to cellular chromosomes is not understood. For human papillomavirus, Epstein-Barr virus, and Kaposi’s sarcoma-associated herpesvirus, viral genome tethering is required for persistence (latency) and pathogenesis (oncogenesis). Like these viruses, HCMV also achieves latency, and it modulates the properties of glioblastoma multiforme tumors. Therefore, defining the mechanism through which IE19 tethers viral genomes to cellular chromosomes may help us understand, and ultimately combat or control, HCMV latency and oncomodulation.
Draft genome sequences of antibiotic-resistant
Serratia
and
Enterobacter
species isolated from imported fresh produce in Georgia, USA
Authors: Kassem Issmat I. , Wang Jiayue , Gorbani Tajani Anahita , Esseili Malak A. , Hassan Jouman , Yassine Iman , Osman Marwan , Bisha Bledar 
Published: May 2024

ABSTRACT

Imported foods play an essential role in food security and in fulfilling consumer demand. However, these foods can also carry antibiotic-resistant bacteria, which might be introduced into the country of importation. Here, we report the draft genomes of antibiotic-resistant bacteria that were isolated from imported fresh produce in Georgia, USA.
Selective bacteriophages reduce the emergence of resistant bacteria in bacteriophage-antibiotic combination therapy
Authors: Azam Aa Haeruman , Sato Koji , Miyanaga Kazuhiko , Nakamura Tomohiro , Ojima Shinjiro , Kondo Kohei , Tamura Azumi , Yamashita Wakana , Tanji Yasunori , Kiga Kotaro 
Published: May 2024

ABSTRACT

Escherichia coli
O157:H7 is a globally important foodborne pathogen with implications for food safety. Antibiotic treatment for O157 may potentially contribute to the exacerbation of hemolytic uremic syndrome, and the increasing prevalence of antibiotic-resistant strains necessitates the development of new treatment strategies. In this study, the bactericidal effects and resistance development of antibiotic and bacteriophage monotherapy were compared with those of combination therapy against O157. Experiments involving continuous exposure of O157 to phages and antibiotics, along with genetic deletion studies, revealed that the deletion of
glpT
and
uhpT
significantly increased resistance to fosfomycin. Furthermore, we found that OmpC functions as a receptor for the PP01 phage, which infects O157, and FhuA functions as a receptor for the newly isolated SP15 phage, targeting O157. In the
glpT
and
uhpT
deletion mutants, additional deletion in
ompC
, the receptor for the PP01 phage, increased resistance to fosfomycin. These findings suggest that specific phages may contribute to antibiotic resistance by selecting the emergence of gene mutations responsible for both phage and antibiotic resistance. While combination therapy with phages and antibiotics holds promise for the treatment of bacterial infections, careful consideration of phage selection is necessary.

IMPORTANCE

The combination treatment of fosfomycin and bacteriophages against
Escherichia coli
O157 demonstrated superior bactericidal efficacy compared to monotherapy, effectively suppressing the emergence of resistance. However, mutations selected by phage PP01 led to enhanced resistance not only to the phage but also to fosfomycin. These findings underscore the importance of exercising caution in selecting phages for combination therapy, as resistance selected by specific phages may increase the risk of developing antibiotic resistance.
Engineering of chimeric enzymes with expanded tolerance to ionic strength
Authors: Mitkowski Paweł , Jagielska Elżbieta , Sabała Izabela 
Published: May 2024

ABSTRACT

Antimicrobial resistance poses a significant global threat, reaching dangerously high levels as reported by the World Health Organization. The emergence and rapid spread of new resistance mechanisms, coupled with the absence of effective treatments in recent decades, have led to thousands of deaths annually from infections caused by drug-resistant microorganisms. Consequently, there is an urgent need for the development of new compounds capable of combating antibiotic-resistant bacteria. A promising class of molecules exhibiting potent bactericidal effects is peptidoglycan hydrolases. Previously, we cloned and characterized the biochemical properties of the M23 catalytic domain of the EnpA (EnpA
CD
) protein from
Enterococcus faecalis
. Unlike other enzymes within the M23 family, EnpA
CD
demonstrates broad specificity. However, its activity is constrained under low ionic strength conditions. In this study, we present the engineering of three chimeric enzymes comprising EnpA
CD
fused with three distinct SH3b cell wall-binding domains. These chimeras exhibit enhanced tolerance to environmental conditions and sustained activity in bovine and human serum. Furthermore, our findings demonstrate that the addition of SH3b domains influences the activity of the chimeric enzymes, thereby expanding their potential applications in combating antimicrobial resistance.

IMPORTANCE

These studies demonstrate that the addition of the SH3b-binding domain to the EnpA
CD
results in generation of chimeras with a broader tolerance to ionic strength and pH values, enabling them to remain active over a wider range of conditions. Such approach offers a relatively straightforward method for obtaining antibacterial enzymes with tailored properties and emphasizes the potential for proteins’ engineering with enhanced functionality, contributing to the ongoing efforts to address antimicrobial resistance effectively.
Global Transcriptome Analysis Reveals Corresponding Genes and Key Pathways Involved in Oxidative Stress in Mouse Small Intestinal Cells
Authors: He Y. , Feng C. P. , Li J. L. , Du R. 
Published: May 2024

Abstract
Understanding the molecular mechanisms involved in the effects of oxidative stress in humans and animals is important to minimize the damage it causes, leading to various intestinal diseases. Our aim is to study the genes and pathways involved in oxidative stress in the gut using mouse small intestinal epithelial cells (MODE-K) as a model. The MODE-K cell line was divided into two different groups: one group was treated with hydrogen peroxide (H2O2) and the other group was not. To analyze the effects of H2O2 exposure, cell viability, apoptosis rate and reactive oxygen species (ROS) levels were determined. Next, transcriptome sequencing was performed, differentially expressed genes (DEGs) were identified and function annotation was performed, followed by a series of bioinformatics analyses. Real-time PCR was used to confirm the transcriptome data. Our results showed that H2O2-induced oxidative stress significantly increased ROS synthesis and promoted cell apoptosis in mouse small intestinal epithelial cells. During oxidative stress, 1207 DEGs (859 up-regulated, 348 down-regulated) were identified. According to GO analysis, DEGs are annotated into 51 different GO classifications including 22 biological processes, 15 cellular components and 14 molecular functions. In addition, using KEGG, PPI and correlation analysis, the two most significant subnetworks were identified. Ten correlated nodal DEGs of the first subnetwork correspond to MAPK, NF-kappa B and PI3K-AKT signaling pathways, and six correlated DEGs of the second subnetwork are associated with mitochondria. KDM6B was found to link these two subnetworks. The results suggest that oxidative stress affects epithelial growth, metabolism and apoptosis in a mouse model of intestinal cells through signaling pathways such as MAPK and PI3K/AKT/NF-kappa B, and mitochondria-related genes that are interconnected through the PTGS2-KDM6B-MT-ATP6 pathway.
Correlation between disease activity and patient-reported health-related quality of life in rheumatoid arthritis: a cross-sectional study
Authors: Feng JunChao , Yu Lingjia , Fang Yingying , Zhang Xianyu , Li Shunping , Dou Lei 
Published: May 2024

ObjectiveWe aimed to provide a comprehensive assessment of health-related quality of life (HRQoL) in patients with rheumatoid arthritis (RA) of different activities and to evaluate the correlation between clinical activity measures and HRQoL instruments. This research also analysed the extent to which different aspects of HRQoL (physical, psychological and social) were affected.DesignCross-sectional, observational, non-interventional study.SettingThe study was conducted at the Department of Rheumatology and Immunology, Qilu Hospital, Shandong University.MethodsFrom December 2019 to October 2020, a total of 340 RA patients participated in the survey using convenient sampling. Three generic instruments, EQ-5D-5L,SF-12 and the AQoL-4D, as well as an RA-specific instrument,the Stanford Health Assessment Questionnaire Disability Index (HAQ-DI), were administered to assess patients’ HRQoL. The Disease Activity Score 28-Erythrocyte Sedimentation Rate (DAS28-ESR) was used by doctors to measure patients’ clinical activity. Multivariable linear regression was used to compare patients’ HRQoL across different levels of activity. Spearman’s correlation was used to assess the correlation between doctor-reported clinical activity and HRQoL.ResultsA total of 314 patients with RA participated in this study. The mean score of HAQ-DI was 0.87 (SD: 0.91). Using patients in the clinical remission group as a reference, patients in the moderate and high disease activity groups showed significantly reduced health state utility values and HRQoL scores (all p<0.05). On the contrary, there was an increase in HAQ-DI scores, indicating more impairment (p<0.05). All instruments included in the study tended to differentiate disease activity based on multiple criteria, with scores showing a moderate to strong correlation with RA activity (|rs|=0.50 to 0.65). Among them, the disease-specific instrument had the highest correlation.ConclusionsRA can have considerable impairment on patients’ HRQoL, both in terms of physical and psychosocial functioning. Given the strong correlation between clinical activity and HRQoL scores, and the fact that HRQoL can be an important clinical supplement. The EQ-5D-5L is probably the most appropriate generic measurement instrument for measuring HRQoL in RA patients.
Prevalence and associated factors of neurocognitive disorder among people living with HIV/AIDS in the South Gondar zone primary hospitals, North-West Ethiopia: an institution-based cross-sectional study
Authors: Kelebie Mulualem Admasu , Tinsae Techilo , Alemayehu Biruk Fanta , Walelign Getasew Kibralew , Takelle Girmaw Medfu 
Published: May 2024

ObjectiveTo assess the prevalence and associated factors of neurocognitive disorder among people living with HIV/AIDS in South Gondar primary hospitals, North-West Ethiopia, 2023.DesignInstitution-based cross-sectional study design.SettingSouth Gondar primary hospitals, North-West Ethiopia.Participants608 participants were recruited using the systematic random sampling technique.MeasurementData were collected using an interviewer-administered questionnaire and medical chart reviews. The International HIV Dementia Scale was used to screen for neurocognitive disorder. The data were entered through EPI-DATA V.4.6 and exported to SPSS V.21 statistical software for analysis. In the bivariable logistic regression analyses, variables with a value of p<0.25 were entered into a multivariable logistic regression analysis to identify factors independently associated with neurocognitive disorder. Statistical significance was declared at a value of p<0.05.ResultsThe prevalence of neurocognitive disorder among HIV-positive participants was 39.1%. In multivariable logistic regression, lower level of education (adjusted OR (AOR)=2.94; 95% CI 1.29 to 6.82), unemployment (AOR=2.74; 95% CI 1.29 to 6.84) and comorbid medical illness (AOR=1.80; 95% CI 1.03 to 3.14) were significantly associated with neurocognitive disorder.ConclusionHIV-associated neurocognitive problems affected over a third of the participants. According to the current study, comorbid medical conditions, unemployment and low educational attainment are associated with an increased risk of neurocognitive disorder. Therefore, early detection and treatment are essential.