bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic variation in neotropical butterflies is associated with sampling scale, species distributions, and historical forest dynamics
Authors: Attiná Natalí , Núñez Bustos Ezequiel O. , Lijtmaer Darío A. , Hebert Paul D. N. , Tubaro Pablo L. , Lavinia Pablo D.
Published: June 2021

Previous studies of butterfly diversification in the Neotropics have focused on Amazonia and the tropical Andes, while southern regions of the continent have received little attention. To address the gap in knowledge about the Lepidoptera of temperate South America, we analysed over 3000 specimens representing nearly 500 species from Argentina for a segment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Representing 42% of the country's butterfly fauna, collections targeted species from the Atlantic and Andean forests, and biodiversity hotspots that were previously connected but are now isolated. We assessed COI effectiveness for species discrimination and identification and how its performance was affected by geographic distances and taxon coverage. COI data also allowed to study patterns of genetic variation across Argentina, particularly between populations in the Atlantic and Andean forests. Our results show that COI discriminates species well, but that identification success is reduced on average by ~20% as spatial and taxonomic coverage rises. We also found that levels of genetic variation are associated with species' spatial distribution type, a pattern which might reflect differences in their dispersal and colonization abilities. In particular, intraspecific distance between populations in the Atlantic and Andean forests was significantly higher in species with disjunct distributions than in those with a continuous range. All splits between lineages in these forests dated to the Pleistocene, but divergence dates varied considerably, suggesting that historical connections between the Atlantic and Andean forests have differentially affected their shared butterfly fauna. Our study supports the fact that large‐scale assessments of mitochondrial DNA variation are a powerful tool for evolutionary studies.
Thermodynamics shapes the biogeography of propionate‐oxidizing syntrophs in paddy field soils
Authors: Jin Yidan , Jiao Shuo , Dolfing Jan , Lu Yahai
Published: June 2021

Soil biogeochemical processes are not only gauged by the dominant taxa in the microbiome but also depend on the critical functions of its ‘rare biosphere’ members. Here, we evaluated the biogeographical pattern of ‘rare biosphere’ propionate‐oxidizing syntrophs in 113 paddy soil samples collected across China. The relative abundance, activity and growth potential of propionate‐oxidizing syntrophs were analysed to provide a panoramic view of syntroph biogeographical distribution at the continental scale. The relative abundances of four syntroph genera, Syntrophobacter, Pelotomaculum, Smithella and Syntrophomonas were significantly greater at the warm low latitudes than at the cool high latitudes. Correspondingly, propionate degradation was faster in the low latitude soils compared with the high latitude soils. The low rate of propionate degradation in the high latitude soils resulted in a greater increase of the total syntroph relative abundance, probably due to their initial low relative abundances and the longer incubation time for propionate consumption. The mean annual temperature (MAT) is the most important factor shaping the biogeographical pattern of propionate‐oxidizing syntrophs, with the next factor being the soil's total sulfur content (TS). We suggest that the effect of MAT is related to the thermodynamic conditions, in which the endergonic constraint of propionate oxidation is leveraged with the increase of MAT. The TS effect is likely due to the ability of some propionate syntrophs to facultatively perform sulfate respiration.
How does independent directors’ reputation influence pay‐for‐performance? Evidence from China
Authors: Yang HaiYan , Yao Daifei (Troy) , Qu Xin
Published: June 2021

We examine the impact of independent directors’ reputations on executive pay‐performance sensitivity. Using hand‐collected data from listed Chinese companies from 2012 to 2017, we find a positive association between independent directors’ reputations and pay‐performance sensitivity that is more pronounced in companies with less concentrated ownership. Further, the results show that reputable directors have a stronger influence on pay‐performance sensitivity when they sit on a remuneration committee, are in state‐owned enterprises, and are in companies with higher agency costs. Our results highlight the monitoring role of reputable independent directors in setting effective executive compensation contracts.
Shaping efficiency of XP‐endo shaper and Mtwo instruments in long oval root canals: A micro‐CT study
Authors: Marques Juliana Lisboa Couto , Freire Laila Gonzales , Scardini Iandara de Lima , Vieira Basilio Rodrigues , de Sousa Frederico Barbosa , dos Santos Marcelo
Published: June 2021

This study evaluated the shaping ability of XP‐endo Shaper and Mtwo systems in long‐oval‐shaped canals of extracted human mandibular molars using micro‐computed tomography (micro‐CT). Images recorded before and after preparation were evaluated for morphometric measures regarding increase in canal volume, dentin removed, surface area, untouched walls and structure model index (SMI). Data were statistically analysed using the Mann–Whitney test with 5% of significance. On both groups, the root canal preparation significantly increased all analysed parameters (P > 0.05). There was no statistical difference between XP‐endo Shaper and Mtwo systems in the increase of the canal volume (30.50%–27.82%), in volume of dentin removed (2.77%–2.40%), in the increase of the canal surface area (11.30%–8.86%), in canal untouched surfaces (9.57%–8.51%) and in the SMI (2.59%–2.68%), respectively. XP‐endo Shaper and Mtwo systems showed similar shaping efficiency and were not able to completely prepare the walls of long‐oval‐shaped canals of extracted human mandibular molars.
Late‐onset eccrine syringofibroadenoma of the feet in a patient with hypohidrotic ectodermal dysplasia
Authors: Khan Hina Ali , Kumarasinghe Prasad , Wood Benjamin
Published: June 2021

A 56‐year‐old woman with hypohidrotic ectodermal dysplasia presented with a 10‐year history of persisting wart‐like skin lesions on her feet. Biopsy revealed changes of eccrine syringofibroadenoma. These lesions are rare, with only nine case reports describing an association with ectodermal dysplasia of hidrotic type (Clouston and Schopf’s syndrome). To our knowledge, this is the first case of eccrine syringofibroadenoma developing in the hypohidrotic/anhidrotic subtype of ectodermal dysplasia.
Cutaneous symplastic hemangioma: A series of four cases
Authors: Frew Derek , Scarborough Richard , Ko Jennifer S. , Billings Steven D.
Published: June 2021

Symplastic hemangiomas (SH) are benign vascular lesions that show atypia in vascular smooth muscle and interstitial cells with sparing of endothelial cells. We present four cases of this rare tumor. The patients (two males; two females) ranged in age from 57 to 83 years (median 74); lesions were located on the leg (n = 3) and back (n = 1), and ranged from 6 to 8 mm. SH were well‐circumscribed and dermal‐based, often with an epidermal collarette (3/4). They were characterized by the presence of variably atypical, hyperchromatic/pleomorphic epithelioid to spindled cells within vascular walls (3/4) and/or perivascular stroma (4/4). Atypical multinucleated cells were present in three of four cases. The overall mitotic rate was low (0‐2 mitotic figures per 10 HPFs; mean 0.75 per 10 HPFs), but atypical mitotic figures were seen in two of four cases. Atypical cells were negative for SMA (0/2), desmin (0/2), AE1/3 (0/2), and CAM5.2 (0/1). ERG, CD31, and CD34 stains were positive in endothelial cells but negative in atypical cells (4/4). Lesional cells and vessels were negative for podoplanin (3/3). Symplastic hemangioma is a benign tumor with bizarre atypia that may be mistaken for malignancy. We present four cases of this rare entity to increase awareness of this tumor and discuss the differential diagnosis.
Choice of radiography in orthodontic treatment on children and adolescents: A questionnaire‐based study performed in Sweden
Authors: Stervik Christina , Lith Agneta , Westerlund Anna , Ekestubbe Annika
Published: June 2021

The aim was to investigate the objective and choice of different radiographic examinations used in orthodontic treatment of children and adolescents, using a web‐based questionnaire directed toward specialists in orthodontics. The questionnaire was distributed to 255 orthodontists in Sweden. In total, 142 responses were received, and 11 specialists were interviewed. Questions were related to the use of radiography during different treatment stages; modifications to the treatment regimen owing to radiographic findings; and the use of and/or need for guidelines in radiography. Radiographic examinations were performed in all treatment stages and mainly during treatment planning. Panoramic radiographs were always or often used by the respondents (99%), less frequently used were lateral radiographs (66%) and intra‐oral radiographs of the incisor regions (69%). Cone beam computed tomography (CBCT) was sparsely employed. A majority of the respondents considered that radiographic findings often or occasionally affected the treatment. Local‐ or clinic‐specific guidelines were used by 85% of respondents. The need for national guidelines was considered low. The frequent use of panoramic radiography together with application of local guidelines, may indicate that radiographic selection criteria are not individualised. National guidelines might facilitate updates on radiographic techniques, and on radiation doses and risks in young patients.
A mixed‐effect model approach for assessing land‐based mitigation in integrated assessment models: A regional perspective
Authors: Diniz Oliveira Thais , Brunelle Thierry , Guenet Bertrand , Ciais Philippe , Leblanc Florian , Guivarch Céline
Published: June 2021

Given the prospects of low short‐term emissions reduction, carbon removals (CDRs) are expected to play an important role in achieving ambitious mitigation targets in future scenarios of integrated assessment models (IAMs), particularly Bioenergy with Carbon Capture and Storage (BECCS). In this paper, we explore the IAMC 1.5℃ database to depict the characteristics of the two main CDR options present in mitigation scenarios: BECCS and afforestation/reforestation. We apply a linear mixed‐effect model to capture the specific regional and cross‐IAM effects. Results reveal that the distribution of BECCS and afforestation deployment differs across IAMs and regions and, to a second extent, time. BECCS is preferred in the scenarios not for its ability to expand energy use but actually because it appears as an alternative to afforestation, which is associated with a decrease in energy use. However, the regional distribution of CDR deployment does not show a common pattern across scenarios and IAMs. Therefore, a more comprehensive investigation is needed before it can support policy proposals.
Association of the CD14 ‐260C/T polymorphism with plaque‐induced gingivitis depends on the presence of Porphyromonas gingivalis
Authors: Bartosova Michaela , Borilova Linhartova Petra , Musilova Kristina , Broukal Zdenek , Kukletova Martina , Kukla Lubomir , Izakovicova Holla Lydie
Published: June 2021

Background

Plaque‐induced gingivitis is the most prevalent periodontal disease associated with pathogenic biofilms. The host immune system responds to pathogens through pattern recognition receptors (PRRs), such as Toll‐like receptors (TLRs) and their co‐receptor cluster of differentiation 14 (CD14).

Aim

This study investigated the association between the functional polymorphism in the CD14 gene and the dental plaque microbiota in children with gingivitis.

Design

A total of 590 unrelated children (307 with plaque‐induced gingivitis and 283 controls, aged 13‐15 years) were enrolled in this case‐control study. Dental plaque was processed using a ParoCheck® 20 detection kit. The CD14 ‐260C/T (rs2569190) polymorphism was determined with the PCR‐RFLP method.

Results

Gingivitis was detected in 64.2% of boys and 35.8% of girls (P < .001). Children with gingivitis had a significantly higher occurrence of dental caries (P < .001). No significant differences in the CD14 ‐260C/T allele and genotype distribution among individuals with or without gingivitis in the whole cohort were found. Children with gingivitis and P gingivalis, however, were significantly more frequent carriers of the CT and TT genotypes than children with gingivitis without P gingivalis or healthy controls (P < .05).

Conclusions

The CD14 ‐260C/T polymorphism acts in cooperation with P gingivalis to trigger plaque‐induced gingivitis in Czech children.
Information flow and nursing care during the early phase of the COVID‐19 pandemic
Authors: Cha Chiyoung , Park Suhyun
Published: June 2021

Aims

This study aimed to understand the dissemination of information relating to coronavirus disease 2019 (COVID‐19) and its impact on nursing care in the early phase of transmission.

Background

COVID‐19 has spread globally, causing an unprecedentedly large number of casualties. Nurses face challenges in dealing with patients with COVID‐19 with limited information about the pathogen.

Design

This qualitative study followed the COREQ guidelines.

Methods

Fifteen nurses were recruited from two university hospitals in South Korea using a snowballing technique for in‐depth interviews in May 2020. All interviews were recorded and transcribed verbatim. Content analysis was performed on the interview data.

Results

Two themes emerged: access to COVID‐19 information and the impact of information on nursing care. The categories of access to COVID‐19 information were lack of nursing‐specific information, limited information cascading from top management and confusion due to varying points of view. The categories of the impact of information on nursing care were unprepared management that aggravates exhaustion, lack of personal protective equipment that creates anxiety and being a nurse leader to overcome the pandemic.

Conclusion

During a pandemic of emerging infectious diseases, nurses should have access to up‐to‐date information tailored to their working environment. Human resources, material resources and systematic support are needed for nurses who provide care for patients with an infectious disease.

Relevance to clinical practice

A collaborative interprofessional education system for emerging infectious diseases is needed for effective communication and consistent care during a pandemic. Nurse leaders should be prepared to deliver profession‐specific information for standardised care and respond to nursing management needs by using resources and tailoring the workforce.
Discovery of the novel HLA‐A*11:396 allele in a Chinese Han individual
Authors: Zhong Xian‐xin , Quan Zhan‐rou , Song Lin‐li , Luo Sheng‐hua , Wu Wang‐da
Published: June 2021

One nucleotide substitution in codon 73 of HLA‐A*11:01:01:01 results in a novel allele, HLA‐A*11:396.
Modeling the Flow Around and the Hydrodynamic Drag on Net Meshes Using reef3d
Authors: Wang Gang , Martin Tobias , Huang Liuyi , Bihs Hans
Published: June 2021

The hydrodynamics and flow around net meshes has recently drawn more and more attention because it is closely related to the expected forces on aquaculture. In terms of modeling the hydrodynamic forces on nets, Morison or screen force models are ordinarily. However, they mainly rely on empirical, experimental, or cylindrical hydrodynamic coefficients, neglecting the flow interactions between adjacent net twines. In this study, the open-source hydrodynamic toolbox reef3d is adopted to analyze the flow around net meshes and investigate the hydrodynamic drag on the structure. The simulation accuracy is in good agreement with flume experiments and previous research. The results demonstrate that 2 × 2 or 3 × 3 mesh cases are more reliable for studying the flow around net meshes including the flow interactions around adjacent twines. It is further shown that controlling the solidity of the net through changing net bar diameters has different effects on the flow around meshes than controlling it by the twine length. This article presents a first step in the aim to derive a new empirical formula for the drag coefficients depending on the solidity and fluid properties, which is more appropriate for the physics involved in offshore conditions.
Uncertainty Quantification of Aero-Thermal Performance of a Blade Endwall Considering Slot Geometry Deviation and Mainstream Fluctuation
Authors: Tao Zhi , Guo Zhendong , Song Liming , Li Jun
Published: June 2021

With the ever-increasing aerodynamic and thermal loads, the endwalls of modern gas turbines have become critical areas that are susceptible to manufacturing and operational uncertainties, making them highly prone to thermal failures. Therefore, it is of vital importance to quantify the impacts of input uncertainties on the aero-thermal performance of endwalls. First, based on the Kriging surrogate, an efficient uncertainty quantification (UQ) method suitable for expensive computational fluid dynamics (CFD) problems is proposed. By using this method, the impacts of slot geometry deviations (slot width, endwall misalignment) and mainstream condition fluctuations (turbulence intensity, inlet flow angle) on the aero-thermal performance of endwalls are quantified. Results show that the actual performance of endwalls has a high probability of deviating from its nominal value. The maximum deviations of aerodynamic loss, area-averaged film cooling effectiveness, and area-averaged Nusselt number reach 0.33%, 45%, and 5.0%, respectively. The critical regions that are most sensitive to the input uncertainties are also identified. Second, a global sensitivity analysis method is also performed to pick out the significant uncertain parameters and explore the relationship between input uncertainties and performance output. The inlet flow angle is proved to be the most significant parameter among the four input uncertain parameters. Besides, a positive incidence angle is found to be detrimental to both the aerodynamic performance and the thermal management of endwalls. Finally, the influence mechanisms of the inlet flow angle on endwall aero-thermal performance are clarified by a fundamental analysis of flow and thermal fields.
Computational simulations of respiratory-laryngeal interactions and their effects on lung volume termination during phonation: Considerations for hyperfunctional voice disorders
Authors: Desjardins Maude , Verdolini Abbott Katherine , Zhang Zhaoyan
Published: June 2021

Glottal resistance plays an important role in airflow conservation, especially in the context of high vocal demands. However, it remains unclear if laryngeal strategies most effective in controlling airflow during phonation are consistent with clinical manifestations of vocal hyperfunction. This study used a previously validated three-dimensional computational model of the vocal folds coupled with a respiratory model to investigate which laryngeal strategies were the best predictors of lung volume termination (LVT) and how these strategies' effects were modulated by respiratory parameters. Results indicated that the initial glottal angle and vertical thickness of the vocal folds were the best predictors of LVT regardless of subglottal pressure, lung volume initiation, and breath group duration. The effect of vertical thickness on LVT increased with the subglottal pressure—highlighting the importance of monitoring loudness during voice therapy to avoid laryngeal compensation—and decreased with increasing vocal fold stiffness. A positive initial glottal angle required an increase in vertical thickness to complete a target utterance, especially when the respiratory system was taxed. Overall, findings support the hypothesis that laryngeal strategies consistent with hyperfunctional voice disorders are effective in increasing LVT, and that conservation of airflow and respiratory effort may represent underlying mechanisms in those disorders.
Distribution of bacterial populations in a stratified fjord (mariager fjord, denmark) quantified by in situ hybridization and related to chemical gradients in the water column
Authors: Ramsing N B , Fossing H , Ferdelman T G , Andersen F , Thamdrup B
Published: June 2021

Volumn 62, no. 4, p. 1392, lines 37 and 38: "Aluminum oxide filters (0.2 mm pore size; Anopore; Millipore GmbH, Eschborn, Germany)" should read "Aluminum oxide filters (0.2 (mu)m pore size; Anopore; Whatman, Inc., Clifton, N.J.)." Page 1403, reference 15: "Fenchel, T." should read "Fenchel, T., L. D. Kristensen, and L. Rasmussen." [This corrects the article on p. 1391 in vol. 62.].
Kinetics of phagocyte response to group B streptococcal infections in newborn rats
Authors: Schuit K E , DeBiasio R
Published: June 2021

To test the hypothesis that inadequate in vivo mobilization of leukocytes may contribute to the unique susceptibility of neonates to infection, we studied the kinetics of phagocyte response to neonatal and adult rats to intraperitoneal infection with group B streptococcus, type Ia. The 50% lethal dose was considerably greater for adults than for neonates (1.1 x 10(7) colony-forming units per g versus 2.7 x 10(2) colony-forming units per g). After challenge with group B streptococcus, type Ia, the number of neonatal peritoneal leukocytes increased more slowly than did those of adult rats. For example, at 4 h, the adult neutrophil count was 41 times greater than that of the neonate, but at 24 h, neonatal peritoneal neutrophils had not yet reached the adult 4-h level. Peritoneal macrophages also increased more rapidly in adults than in neonates. After intraperitoneal infection, both adults and neonates developed bacteremia, but adults cleared the bacteria with greater efficiency. Adult blood neutrophils increased 247% by 12 h and then decreased; neonatal neutrophils steadily decreased to a 57% reduction by 24 h. These data suggest that the neonatal neutrophil response to group B streptococcus, type Ia, infection is inadequate and may contribute to the high mortality associated with this infection.
Plasmid-determined resistance to serum bactericidal activity: a major outer membrane protein, the traT gene product, is responsible for plasmid-specified serum resistance in Escherichia coli
Authors: Moll A , Manning P A , Timmis K N
Published: June 2021

Resistance to the bactericidal activity of serum appears to be an important virulence property of invasive bacteria. The conjugative multiple-antibiotic-resistance plasmid R6-5 was found to confer upon Escherichia coli host bacteria increased resistance against rabbit serum. Gene-cloning techniques were used to localize the serum resistance determinant of R6-5 to a segment of the plasmid that encodes conjugal transfer functions, and a pACYC184 hybrid plasmid, designated pKT107, that contains this segment was constructed. The generation and analysis of deletion and insertion mutant derivatives of the pKT107 plasmid that no longer specify serum resistance permitted precise localization of the serum-resistance cistron on the R6-5 map and demonstrated that this locus is coincident with that of traT, one of the two surface exclusion genes of R6-5. Examination of the proteins synthesized in E. coli minicells of pKT107 and its serum-sensitive mutant derivative plasmids confirmed that the serum-resistance gene product of R6-5 is the traT protein and showed that this protein is a major structural component (about 21,000 copies per cell) of the bacterial outer membrane.
Enumeration of immune interferon-producing cells induced by allogeneic stimulation
Authors: Ito Y , Aoki H , Kimura Y , Takano M , Maeno K , Shimokata K
Published: June 2021

We succeeded in enumerating interferon-producing cells induced by allogeneic stimulation, and proved that they were indeed T lymphocytes. The peak level of these cells in spleen was attained on day 5 after immunication, was maintained for about 2 days, and declined thereafter. Titers of interferon produced in vitro by sensitized spleen cells were maximum on day 7. This suggests that the maturation of immune interferon-producing cells follows cell proliferation after antigen stimulation.
Interaction of
Nocardia asteroides
with Rabbit Alveolar Macrophages: Association of Virulence, Viability, Ultrastructural Damage, and Phagosome-Lysosome Fusion
Authors: Davis-Scibienski Carole , Beaman Blaine L.
Published: June 2021

In vitro-maintained rabbit alveolar macrophages were infected with three strains of
Nocardia asteroides
. It was found that
N. asteroides
GUH-2 was resistant to macrophage killing, while
N. asteroides
14759 was intermediate in resistance, and
N. asteroides
10905 had little resistance to killing by macrophages. These observations correlated well with the data on relative virulence previously determined in mice. To establish the intracellular events leading to these differences, we determined the occurrence of phagosome-lysosome fusion in infected macrophages by both electron and fluorescent microscopic methods. It was found that the virulent strain GUH-2 inhibited phagosome-lysosome fusion; the intermediately virulent strain, 14759, partially inhibited fusion; and the less-virulent strain, 10905, was unable to inhibit fusion. In addition, electron microscopy of infected macrophages demonstrated that cells of the virulent strain, GUH-2, were not damaged, and only some of the cells of the intermediately virulent strain, 14759, were damaged, while most of the cells of the less virulent strain, 10905, exhibited considerable cellular destruction. These data indicated a direct correlation between the virulence of these organisms and their resistance to killing by alveolar macrophages, their lack of macrophage-induced ultrastructural damage, and their ability to inhibit phagosome-lysosome fusion. Thus, it appears that inhibition of phagosome-lysosome fusion in alveolar macrophages may be one of the mechanisms of pathogenicity of virulent strains of
N. asteroides.
Graphical method for evaluating antibody response to vaccines
Authors: Siber G R , Ransil B J , Schiffman G
Published: June 2021

We describe a technique which facilities the presentation, analysis, and interpretation of antibody responses elicited by vaccines or other immune stimuli.
Intracellular multiplication of Legionella pneumophila in cultured human embryonic lung fibroblasts
Authors: Wong M C , Ewing E P , Callaway C S , Peacock W L
Published: June 2021

Cell cultures of normal human embryonic lung fibroblasts were inoculated with two strains of Legionella pneumophila, the etiological agent of Legionnaires disease. Large numbers of intact organisms, including many dividing forms, were seen within fibroblasts by light and electron microscopy. Intracellular multiplication of organisms was demonstrated by the progressive increase in bacterial colony counts from plated extracts of infected fibroblast cultures in which extracellular multiplication had been eliminated by bactericidal concentrations of antibiotics. It is evident that L. pneumophila can thrive in an intracellular environment, and this property may be significant in the pathogenesis of Legionnaires disease.
Production of Clostridium difficile antitoxin
Authors: Ehrich M , Van Tassell R L , Libby J M , Wilkins T D
Published: June 2021

We have produced antitoxin to the toxin of Clostridium difficile in rabbits and in goats. Antitoxin dilutions of 1/8,000 and 1/5,120 were capable of neutralizing lethal doses of the toxin in mice and in tissue culture, respectively.
Antibody-mediated neutralization of virus is abrogated by mycoplasma
Authors: Dickson C , Elkington J , Hales A , Weiss R
Published: June 2021

The ability of a mouse mammary tumor cell line to abrogate antibody neutralization of vesicular stomatitis virus was shown to be due to the presence of mycoplasma. The mycoplasma was isolated from the cell line and typed as Mycoplasma orale. Colonies of this mycoplasma were used to deliberately infect cell cultures which then gained the capacity to reactivate antibody-neutralized virus. The extent of the reactivation depended on the source of neutralizing antiserum. Other species of mycoplasma were tested and were found to reactivate neutralized virus, indicating that this may be a general phenomenon of mycoplasma contamination.
Bacterial phagocytosis by macrophages from lipopolysaccharide responder and nonresponder mouse strains
Authors: Cuffini A , Carlone N A , Forni G
Published: June 2021

The phagocytic capacity of macrophages from C3H/H3J mice was assessed against lipopolysaccharide-producing (Escherichia coli) and -nonproducing (Staphylococcus aureus) bacteria. Despite their gene-coded unresponsiveness to lipopolysaccharide endotoxin and lymphokines and their defective tumoricidal activity, proteose peptone-induced C3H/HeJ macrophages did not display a defective phagocytic capacity, but rather displayed an enhanced phagocytosis of both bacterial strains compared with macrophages from closely related C3H/HeN mice. Unstimulated peritoneal resident C3H/HeJ macrophages, on the other hand, displayed a normal phagocytic activity toward E. coli and enhanced phagocytosis toward S. aureus.
Lymphoproliferative responses to oral bacteria in humans with varying severities of periodontal disease
Authors: Patters M R , Chen P , McKenna J , Genco R J
Published: June 2021

We assessed in vitro the lymphocyte blastogenic resp onsess of peripheral blood lymphocytes to antigen extracts of a large battery of oral microorganisms in a population of humans with varying severities of periodontal disease. When the magnitudes and frequencies of statistically positive blastogenic responses to various oral microorganisms were compared, three general patterns emerged. The Actinomyces species proved to be potent stimulators of lymphocyte blastogenesis in most subjects tested, whereas Streptococcus sanguis, Campylobacter, and Eikenella corrodens stimulated few individuals. The response to these organisms correlated poorly with the severity of periodontal disease in the tested patients. However, several gram-negative anaerobic organisms, including Bacteroides asaccharolyticus and Treponema denticola, elicited statistically more frequent positive response in subjects with destructive periodontitis compared with patients with gingivitis. These results, taken together with recent microbiological findings, suggest that the specificity of the lymphocyte blastogenic response to antigens of oral bacteria correlates with the presence of these organisms in the subgingival microflora during various periodontal disease states.
Effect of Mycobacterium bovis BCG vaccination upon Mycobacterium lepraemurium infection
Authors: Lefford M J , Morgan R , Logie P S
Published: June 2021

Mice were infected with 10(8) Mycobacterium lepraemurium in the footpad (unsuppressed mice), and some of these animals were concurrently given 10(9) heat-killed M. lepraemurium intravenously (suppressed mice). These groups of mice were preimmunized with 10(7) viable organisms of Mycobacterium bovis BCG by several routes. BCG inhibited the proliferation of M. lepraemurium in the unsuppressed mice, but not in the suppressed mice. In effect, the intravenous administration of heat-killed M. lepraemurium suppressed the immunity to M. lepraemurium that BCG vaccination had engendered. BCG did not protect normal mice against intravenous infection with M. lepraemurium. It appears that normal mice against intravenous infection with M. lepraemurium. It appears that the inhibitory effect of BCG vaccination upon M. lepraemurium infection is due to cross-reactive immunity rather than to nonspecific immunity or immunopotentiation. Thus, the route of BCG vaccination was immaterial, and vaccination 12 weeks before M. lepraemurium infection was as beneficial as vaccination 4 weeks before infection. Moreover, spleen cells from M. lepraemurium-immunized mice conferred adoptive immunity to BCG. The implications of this study for the use of BCG as a prophylactic and therapeutic agent in human leprosy are discussed.
Learning Geomicrobiology as a Team Using Microbial Mats, a Multidisciplinary Approach
Authors: Rios-Velazquez Carlos , Casillas-Martinez Lilliam , Visscher Pieter T.
Published: June 2021

Microbial mats are one of the best suited laminar organo-sedimentary ecosystems for students from different educational backgrounds to visualize the direct relationship between microbes and minerals. We have used tropical hypersaline microbial mats from Puerto Rico as educational tools to promote active learning of geomicrobiology introductory concepts for undergraduate students organized in multidisciplinary teams with biological and geological backgrounds. Besides field trips and independent research projects focused on microbial mats, four intensive workshops and one capstone activity were designed to expose students to the different geomicrobiology subdisciplines (microbiology, molecular biology, geology, and geochemistry). The teaching-learning process was assessed using pre- and posttests, group discussions, activities including Gallery Walks and exquisite cadaver’s, case studies, and focal interviews. While the posttest showed a significant difference in conceptual understanding, the Gallery Walk and the capstone activities demonstrated increase in the depth, coherence, and thoughtfulness in answering questions, including a clear integration of the different subdisciplines during their presentations. Finally, the main themes described by the students as important outcomes of their participation in the Research at Undergraduate Institutions: Microbial Observatory (RUI-MO) program were: (i) the opportunity to study and learn new and different science disciplines, (ii) the microbial mats were excellent tools to learn from and integrate different science disciplines, and (iii) working in multidisciplinary teams gave them the opportunity to learn from their peers’ discipline backgrounds. To our knowledge this is the first educational initiative that uses tropical hypersaline microbial mats to teach geomicrobiology in a multidisciplinary fashion.
DNA Microarrays in the Undergraduate Microbiology Lab: Experimentation and Handling Large Datasets in as Few as Six Weeks
Authors: Kushner David B.
Published: June 2021

DNA microarrays have significantly impacted the study of gene expression on a genome-wide level but also have forced a more global consideration of research questions. As such, it has become critical to introduce undergraduate students to genomics approaches to research. A challenge with performing a DNA microarray experiment in the teaching lab is determining the time required for the study and how to handle the voluminous data generated. At an unexpectedly low cost, a 6-week, project-based lab module has been developed that provides 3 weeks for wet lab (hands-on work with the DNA microarrays) and 3 weeks for dry lab (analyzing data, using databases to help with data analysis, and considering the meaning of data within the large dataset). Options exist for extending the number of weeks dedicated to the project, but 6 weeks is sufficient for providing an introduction to both experimental genomics and data analysis. Students indicate that being able to both perform array experiments and thoroughly analyze data enriches their understanding of genomics and the complexity of biological systems.
mRNA abundance changes during flagellar regeneration in Chlamydomonas reinhardtii
Authors: Schloss J A , Silflow C D , Rosenbaum J L
Published: June 2021

Flagellar amputation in Chlamydomonas reinhardtii induces the accumulation of a specific set of RNAs, many of which encode flagellar proteins. We prepared a cDNA clone bank from RNA isolated from cells undergoing flagellar regeneration. From this bank, we selected clones that contain RNA sequences that display several different patterns of abundance regulation. Based on quantitation of the relative amounts of labeled, cloned cDNAs hybridizing to dots of RNA on nitrocellulose filters, the cloned sequences were divided into five regulatory classes: class I RNAs remain at constant abundance during flagellar regeneration; classes II, III, and IV begin to increase in abundance within a few minutes after deflagellation, reach maximal abundance at successively later times during regeneration, and return to control cell levels within 2 to 3 h; and class V RNA abundance decreases during flagellar regeneration. Alpha- and beta-tubulin mRNAs are included in regulatory class IV. The abundance kinetics of alpha-tubulin mRNAs differ slightly from those of beta-tubulin mRNAs. The availability of these clones makes possible studies on the mechanisms controlling the abundance of a wide variety of different RNA species during flagellar regeneration in Chlamydomonas.
Effect of undermethylation on mRNA cytoplasmic appearance and half-life
Authors: Camper S A , Albers R J , Coward J K , Rottman F M
Published: June 2021

S-Tubercidinylhomocysteine (STH) is a structural analog of S-adenosylhomocysteine and a potent inhibitor of S-adenosylmethionine-dependent methyltransferase reactions. We investigated the effects of STH on HeLa cell mRNA metabolism. Dual labeling studies reveal that STH dramatically inhibits the methylation of HeLa mRNA in a dose-dependent manner. Analysis of the modified nucleosides and 5'-terminal cap structures in radiolabeled mRNA by high-pressure liquid chromatography indicated that internal N6-methylation of adenosine was reduced by 65% at 50 microM STH and by 83% at 500 microM STH. The N6-methylation of adenosine contained in cap structures was similarly reduced at both concentrations of STH. Substantial amounts of cap structures lacking 2'-O-methylated nucleosides (m7GpppN, cap zero) were detected at the higher level of STH. To test the possibility that methylation affects mRNA stability, cytoplasmic mRNA half-life was measured in a pulse-chase experiment. The half-life of undermethylated mRNA, produced as a consequence of STH treatment, was unchanged compared with the control. To determine whether mRNA methylation is coupled to nuclear processing or transport, the time of cytoplasmic appearance of polyadenylated RNA in STH-treated HeLa cells was compared with untreated cells. STH caused a significant lag in the time of appearance of the polyadenylated RNA, suggesting that mRNA methylation may be required for efficient processing or transport.
Inactivation of p53 gene expression by an insertion of Moloney murine leukemia virus-like DNA sequences
Authors: Wolf D , Rotter V
Published: June 2021

Analysis of Abelson murine leukemia virus-transformed L12 cells which lack the p53 cellular encoded tumor antigen revealed alterations in the p53-specific genomic DNA sequences. The active p53 gene, usually contained in a 16-kilobase EcoRI DNA fragment of p53 producer cells, went through major alterations leading to the appearance of a substantially larger 28.0-kilobase p53-specific EcoRI fragment. Detailed restriction enzyme analysis, with genomic probes spanning throughout the whole active p53 gene, indicated that the L12 p53 altered gene contains all the exons and principal introns of the normal p53 16.0-kilobase gene. However, its structure was interrupted by the integration of a novel DNA segment into the noncoding intervening sequences of the first p53 intron. Analysis of the inserted sequences revealed close homology to Moloney murine leukemia virus. This Moloney leukemia murine virus-like particle resides in a 5' to 3' transcriptional orientation, similar to the p53 gene, permitting the transcription of aberrant fused mRNA molecules detected in these cells.
Supplemental Material: Providencia Island: A Miocene Stratovolcano on the Lower Nicaraguan Rise, Western Caribbean—A Geological Enigma Resolved Item
Authors: Smith Alan L. , al. et
Published: June 2021

Appendix A: U/Pb geochronologic analyses of zircons from Providencia. Appendix B: Sample list. Appendix C: Chemical composition of some possible basaltic sources for the Providencia subalkaline suite. Appendix D: Chemical composition of volcanic rocks from Haiti. Appendix E: Chemical composition of volcanic rocks from the Dominican Republic.
Effect of Nonreciprocal Forces on the Stability of Dust Clusters
Authors: Ignatov A. M.
Published: June 2021

Results are presented from studies of the stability of the plane dust clusters in the form of a regular polygon with the number of particles from two to five. It is assumed that the particles are placed in the plasma consisting of Maxwellian electrons and a directed flow of cold ions. It is shown that, in such clusters, the oscillatory instabilities can develop along with the aperiodic instabilities. The ranges of plasma parameters are determined, within which the oscillatory instability of the five-particle cluster becomes saturated at the weakly nonlinear stage. As a result, the cluster forms a time crystal, which can be a chiral crystal.
Radiative Surface Waves in Layered Plasma–Dielectric Structures and Prospects of Their Application in Plasma Microwave Electronics
Authors: Kartashov I. N. , Kuzelev M. V.
Published: June 2021

Surface waves in layered systems consisting of material media with different frequency dispersions are considered: dielectric–plasma–vacuum, vacuum–plasma–plasma, and dielectric–vacuum–plasma. It is shown that in such systems, one of the surface waves can be radiative into a medium that does not form an interface for the surface wave under consideration, in view of which the wave becomes decaying. In the dielectric–vacuum–plasma system, there is only one surface wave localized at the vacuum–plasma interface, which is radiative into the dielectric in a certain region of wavenumbers with a not too small thickness of the vacuum layer. For all cases, the possibilities of exciting surface waves of a layered structure by an electron beam are analyzed. It is indicated which surface waves will be excited most efficiently. The prospects of using such waves in plasma microwave electronics in the development of sub-terahertz and possibly terahertz frequency ranges are shown.
Exploring the angiographic-biologic phenotype in the IMAGINE study: quantitative UWFA and cytokine expression
Authors: Abraham Joseph R , Wykoff Charles C , Arepalli Sruthi , Lunasco Leina , Yu Hannah J , Martin Alison , Mugnaini Christopher , Hu Ming , Reese Jamie , Srivastava Sunil K , Brown David M , Ehlers Justis P
Published: June 2021

Background

This study investigates the association of intraocular cytokine expression and ultrawide-field fluorescein angiography (UWFA) quantitative imaging biomarkers and their association with angiographical feature response after antivascular endothelial growth factor (VEGF) therapy in diabetic macular oedema (DME).

Methods

The IMAGINE DME study is a post hoc imaging biomarker and intraocular cytokine assessment from the DAVE study, a prospective DME clinical trial that included aqueous humour sampling and UWFA imaging. Fifty-four cytokines associated with inflammation and angiogenesis were evaluated through multiplex arrays. UWFA parameters were assessed using an automated feature analysis platform to determine ischaemic and leakage indices and microaneurysm (MA) count. Eyes were classified into UWFA responder or non-responder groups based on longitudinal quantitative UWFA parameter improvement. Cytokine expression was correlated with UWFA metrics and evaluated in the context of therapeutic response.

Results

Twenty-one eyes were included with a mean age of 55±10 years. Increased panretinal leakage index correlated with VEGF (r=0.70, p=0.0005), angiopoietin-like 4 (r=0.77, p=4.6E-5) and interleukin (IL)-6 (r=0.64, p=0.002). Panretinal ischaemic index was associated with tissue inhibitor of metalloproteinases 1 (TIMP-1, r=0.49, p=0.03) and peripheral ischaemia correlated with VEGF (r=0.45, p=0.05). MA count correlated with increased monocyte chemotactic protein-4 (MCP-4, r=0.60, p=0.004) and platelet and endothelial cell adhesion molecule 1 (PECAM-1, r=0.58, p=0.005). Longitudinal MA reduction was associated with decreased baseline VEGF and urokinase receptor (uPAR) (p<0.05). High baseline VEGF and IL-6 were associated with dramatic reduction in macular leakage (p<0.05).

Conclusions

Baseline and longitudinal quantitative UWFA imaging parameters correlated with multiple aqueous humour cytokine concentrations, including VEGF and IL-6. Further research is needed to assess the possible implications of using these findings for evaluating treatment response.
Diversité des rhizobia associés au genre Hippocrepis en Algérie
Authors: Djouadi Samir , Bouherama Amina , Aïd Fatiha , Amrani Saïd
Published: June 2021

La présente étude porte sur la nature des rhizobia associés aux légumineuses du genre Hippocrepis qui compte une dizaine d’espèces en Algérie et pour laquelle très peu de travaux ont été jusqu’ici consacrés. Les résultats de nos investigations qui ont portés sur 26 plants représentant 8 espèces de ce genre et provenant de 17 localités du nord et du sud du pays révèlent que tous les plants étaient nodulés et fixateurs d’azote, ce qui indique que les 8 espèces identifiées sont capables d’établir une symbiose efficiente avec les rhizobia présents dans les sols qui les supportent. Le séquençage du gène de l’ARN 16S des 26 souches de rhizobia isolées et authentifiées par des tests de nodulation au laboratoire permet de les assigner à 16 espèces de rhizobia réparties sur 5 genres: Ensifer, Mesorhizobium, Bradyrhizobium, Rhizobium et Neorhizobium avec une prédominance des représentants des genres Ensifer et Mesorhizobium. Les résultats de cette étude qui est la première dédiée spécifiquement au genre Hippocrepis indiquent que la symbiose à rhizobia et la capacité d’utiliser, par ce biais, l’azote atmosphérique sont communes chez les représentants de ce genre en Algérie, ils révèlent aussi la grande diversité des rhizobia qui sont associés à ce genre.
A finite box as a tool to distinguish free quarks from confinement at high temperatures
Authors: Glozman L. Ya. , Lang C. B.
Published: June 2021

Above the pseudocritical temperature$$T_c$$Tcof chiral symmetry restoration a chiral spin symmetry (a symmetry of the color charge and of electric confinement) emerges in QCD. This implies that QCD is in a confining mode and there are no free quarks. At the same time correlators of operators constrained by a conserved current behave as if quarks were free. This explains observed fluctuations of conserved charges and the absence of the rho-like structures seen via dileptons. An independent evidence that one is in a confining mode is very welcome. Here we suggest a new tool how to distinguish free quarks from a confining mode. If we put the system into a finite box, then if the quarks are free one necessarily obtains a remarkable diffractive pattern in the propagator of a conserved current. This pattern is clearly seen in a lattice calculation in a finite box and it vanishes in the infinite volume limit as well as in the continuum. In contrast, the full QCD calculations in a finite box show the absence of the diffractive pattern implying that the quarks are confined.