Complete mitochondrial genome of the Korean endemic springtail Tomocerus caputiviolaceus Lee 1975 (Collembola: Tomoceridae)

The complete mitochondrial genome of Tomocerus caputiviolaceus was sequenced and assembled. The complete mitochondrial genome is 15,519 bp in length. The mitogenome contained 37 genes, including 13 protein-coding genes (PCGs), 22 tRNAs, and two rRNAs. In phylogenetic analysis based on the nucleotide sequences of 13 PCGs, T. caputiviolaceus is closely related to Tomocerus qinae Yu, Yao & Hu, 2016, both of which belong to the genus Tomocerus within the family Tomoceridae.

The complete chloroplast genome of Spergularia marina (Caryophyllaceae) and its phylogenetic analysis

Spergularia marina (L.) Griseb, 1843 (Caryophyllaceae) is a halophytic plant widely distributed along the southwestern coast of the Korean Peninsula. In this study, the complete chloroplast genome sequence of S. marina was determined using next-generation sequencing (NGS). The chloroplast genome of S. marina is 152,460 bp in length with 36.7% GC content. It comprises a large single-copy (LSC; 83,321), a small single copy (SSC; 17,205 bp), and a pair of inverted repeats (IRs; 25,967 bp) with a typical quadripartite structure. It consists of 131 genes, including 86 protein-coding genes, 8 ribosomal RNAs, and 37 transfer RNAs. Phylogenetic analysis using complete chloroplast genomes showed that among the 17 Caryophyllaceae species, S. marina is most closely related to Spergula arvensis. Since no complete chloroplast genome of the genus Spergularia has been reported to date, our study provides useful genetic information for determining phylogenetic relationships within the Caryophyllaceae.

Large language models and agricultural extension services

Several factors have traditionally hampered the effectiveness of agricultural extension services, including limited institutional capacity and reach. Here we assess the potential of large language models (LLMs), specifically Generative Pre-trained Transformer (GPT), to transform agricultural extension. We focus on the ability of LLMs to simplify scientific knowledge and provide personalized, location-specific and data-driven agricultural recommendations. We emphasize shortcomings of this technology, informed by real-life testing of GPT to generate technical advice for Nigerian cassava farmers. To ensure a safe and responsible dissemination of LLM functionality across farming worldwide, we propose an idealized LLM design process with human experts in the loop.

Complete mitochondrial genome of the composting worm Dendrobaena veneta (Clitellata: Oligochaeta, Lumbricidae)

Dendrobaena veneta (Rosa, 1886) is widely distributed all over Europe due to its use as compost worm. The specimen presented here was collected in Tiranë district, Albania. Currently, only two species' complete or nearly complete mitochondrial genome (mitogenome) sequences have been reported in the genus Dendrobaena; D. octaedra (Savigny, 1826) and D. tellermanica Perel, 1966. In this study, the complete mitogenome of D. veneta was sequenced, assembled, and annotated. The mitogenome of D. veneta is a circular DNA molecule, consisting of 15,475 bp with an A + T content of 61.2%. It contains 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and 1 non-coding region (control region). Phylogenetic analysis showed that D. veneta is clustered with the other two Dendrobaena species in the well-supported family Lumbricidae.

The complete mitochondrial genome of the Korean endemic earthworm Amynthas deogyusanensis (Clitellata: Megascolecidae)

The Korean endemic earthworm Amynthas deogyusanensis Hong and James, 2001 (Clitellata: Megascolecidae) is found in the forest area of Deogyu Mountain, South Korea. In this study, the complete mitochondrial genome (mitogenome) of A. deogyusanensis was sequenced, assembled, and annotated. The mitogenome of A. deogyusanensis is a circular DNA molecule, consisting of 15,257 bp with an A + T content of 67.9%. It contains 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and one non-coding region (control region). Phylogenetic analysis suggested that the family Megascolecidae is a monophyletic group with full support, whereas the genus Amynthas is non-monophyletic with the genera Metaphire and Duplodicodrilus.

The complete chloroplast genome sequence of Berchemia racemosa Siebold & Zucc. (Rhamnaceae), a rare plant species in Korea

Berchemia racemosa Siebold & Zucc., 1845 is a rare species distributed in restricted areas in the western Korean peninsula. In this study, the complete chloroplast genome (plastome) of B. racemosa was sequenced and assembled by Illumina paired-end sequencing. The plastome of B. racemosa was 161,187 bp in length and was quadripartite in structure, including a large single-copy (LSC) region of 89,503 bp, a small single-copy (SSC) region of 18,214 bp, and two inverted repeats of 26,735 bp. The GC content was 37.2%. The plastome of B. racemosa contains 130 genes, including eight ribosomal RNA (rRNA) genes, 37 transfer RNA (tRNA) genes, and 85 protein-coding genes. Phylogenetic analysis using complete genome sequences showed that B. racemosa is most closely related to Berchemia flavescens.

Complete chloroplast genome sequence of Eranthis byunsanensis B.Y. Sun (Ranunculaceae), an endemic species in Korea

The Korean endemic Eranthis byunsanensis B.Y. Sun, 1993 (Ranunculaceae) is a rare plant distributed in the southwestern part of the Korean Peninsula. The complete chloroplast (cp) genome of E. byunsanensis was sequenced by next-generation sequencing (NGS) using an Illumina HiSeq X platform. The cp genome of E. byunsanensis is 160,324 bp in length with 37.9% GC content. It showed a typical quadripartite structure consisting of a pair of inverted repeats (IRs; 28,356 bp), a large single-copy region (LSC; 87,671 bp), and a small single-copy region (SSC; 15,941 bp). The cp genome comprises 130 genes including 85 protein-coding genes (PCGs), 37 tRNA genes, and eight rRNA genes. The molecular phylogenetic analysis indicates that E. byunsanensis is closely related to Eranthis stellata, both of which belong to the genus Eranthis.

Visualization of Chiral Electronic Structure and Anomalous Optical Response in a Material with Chiral Charge Density Waves

Chiral materials have attracted significant research interests as they exhibit intriguing physical properties, such as chiral optical response, spin-momentum locking, and chiral induced spin selectivity. Recently, layered transition metal dichalcogenide 1T-TaS_{2} has been found to host a chiral charge density wave (CDW) order. Nevertheless, the physical consequences of the chiral order, for example, in electronic structures and the optical properties, are yet to be explored. Here, we report the spectroscopic visualization of an emergent chiral electronic band structure in the CDW phase, characterized by windmill-shaped Fermi surfaces. We uncover a remarkable chirality-dependent circularly polarized Raman response due to the salient in-plane chiral symmetry of CDW, although the ordinary circular dichroism vanishes. Chiral Fermi surfaces and anomalous Raman responses coincide with the CDW transition, proving their lattice origin. Our Letter paves a path to manipulate the chiral electronic and optical properties in two-dimensional materials and explore applications in polarization optics and spintronics.

The complete mitochondrial DNA sequences of two sibling species of lumbricid earthworms, Eiseniafetida (Savigny, 1826) and Eiseniaandrei (Bouché, 1972) (Annelida, Crassiclitellata): comparison of mitogenomes and phylogenetic positioning

Composting earthworms of the genus Eisenia play an important role in soil ecosystems. However, taxonomic classification of this genus, especially the sibling species Eiseniafetida and Eiseniaandrei, is complicated because of their morphological similarity. In this study, we assessed the utility of the complete mitochondrial genome (mitogenome) for identification and differentiation of the two species. The complete mitogenomes of E.andrei and E.fetida were 15,714 and 16,560 bp, respectively. They contained 37 genes, comprising 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes, and a putative non-coding region, as observed in other earthworms. Sequence comparisons based on the complete nucleotide sequences excluding the non-coding region showed 85.8% similarity, whereas the predicted amino acid sequences of the 13 PCGs were 92.7% similar between the two species. In particular, distinct features were found in the non-coding regions of the mitogenomes. They include a control region associated with putative mitogenome replication and an extended sequence. The extended sequence showed significant differences between the two species and other known earthworm species, suggesting its potential as a feasible molecular marker for species identification. Phylogenetic analysis of the 36 mitogenomes of earthworm species corroborated the monophyly of the genus Eisenia and the taxonomic distinctness of the sibling species pair, E.fetida and E.andrei.

Complete mitochondrial genome of the Korean endemic springtail Homidia koreana Lee & Lee, 1981 (Collembola: Entomobryidae)

The Korean endemic springtail Homidia koreana Lee & Lee, 1981 is popular in the leaf litter of various forests of South Korea, probably widely distributed throughout the Korean Peninsula. The complete mitochondrial genome of H. koreana was sequenced, assembled, and annotated. The mitochondrial genome of H. koreana consists of a circular DNA molecule of 14,846 bp, with 68.4% AT content. It comprises 13 protein-coding genes (PCGs), 22 transfer (tRNA) genes, and 2 ribosomal RNA (rRNA) genes. The molecular phylogenetic relationships estimated using MrBayes 3.2 revealed that H. koreana was closely related to Homidia socia Denis, 1929, both of which belong to the genus Homidia.

Early efficacy and safety data with fixed-dose combination calcipotriol/betamethasone dipropionate foam attributed to mechanism of absorption and steroid potency

Topical therapy is the mainstay of treatment for the majority of patients with psoriasis vulgaris (chronic plaque psoriasis), with combinations of vitamin D analogues and glucocorticoids having been shown to negate many of the negative effects associated with either monocomponent individually. Following the established efficacy of fixed‐dose combination calcipotriol (Cal; 50 µg/g) plus betamethasone dipropionate (BD; 0.5 mg/g) ointment and gel formulations, a novel Cal/BD foam formulation was developed. When applied, Cal/BD foam forms a supersaturated solution on the skin, increasing the penetration and bioavailability of Cal and BD. Early data indicate that this results in improved efficacy outcomes versus Cal/BD ointment, without negatively affecting safety outcomes (such as the incidence/severity of side effects or impacted calcium homeostasis or hypothalamic‐pituitary‐adrenal axis). This article discusses the potency and absorption of fixed‐dose combination Cal/BD foam, as well as the positive early efficacy and safety data associated with its utilisation in the treatment of psoriasis vulgaris.

Video abstract

Daphnetin: A novel blue-green photonic switch for disodium phosphates that allows monitoring of polymerase chain reactions

This paper describes the very simple and robust ratiometric photonic switching properties of daphnetin (DP) toward HPO₄^2- ions selectively in complex biological fluids, without any interference from other relevant anions under physiological conditions. The sensing ability of DP toward HPO₄^2- ions was first demonstrated using UV-Vis and fluorescence spectroscopy, dynamic light scattering (DLS), and one- and two-dimensional NMR spectroscopy. DP can detect HPO₄^2- ions at concentrations up to the sub-micromolar/nanomolar level very effectively, with a ratiometric response resulting from intramolecular charge transfer aided by aggregated-induced emission. The interactions between DP and HPO₄^2- ions resulted in new bands appearing in the UV-Vis (at 385 nm) and emission (at 535 nm) spectra. The noncovalently held HPO₄^2- ions induced pronounced specific aggregation of DP molecules, resulting in the new excimer band at 535 nm while retaining the monomer band centered at 445 nm. In contrast, reciprocal absorptivity changes were observed at 320 and 385 nm, with exponential decrements and increments, respectively. This probe could effectively monitor the consumption of dNTPs during various cycles of the polymerase chain reaction performed with relatively short oligonucleotides as well as genomic DNA from Agrobacterium tumefaciens (AcH5α strain).

Predictive modeling for monitoring egg freshness during variable temperature storage conditions

The overall aim of this research was to develop egg freshness prediction models in terms of selected quality indices. Six experiments (4 constant temperatures and 2 variable temperatures) were carried out on hen eggs for a total period of 10, 21, 26, 13, and 105 d at storage temperatures of 30, 20, 20 to 10, 30 to 10, and 5 and 10°C, to observe trends in the relative weight loss (RWL), Haugh unit (HU), yolk index (YI), albumin index (AI), yolk pH, and albumin pH. The results showed that there was an increasing trend in the RWL and a decreasing trend in the YI, AI, and HU for all temperature conditions. The changes in the yolk and albumin pH were not uniform. The data from the constant temperature conditions were used to determine the coefficients of the egg quality prediction models, which consisted of the primary model controlling the change rate of the quality indicator at a temperature condition in differential equation form, and the secondary model controlling the change rate with temperature, which was in quadratic polynomial form. The models were applied to the data from the fluctuating temperature conditions, and the zeroth, third, and eighth order kinetic models described the stepwise change in the RWL, HU, and YI, respectively. The accuracy and bias factor values for the RWL, HU, and YI were 1.116 and 0.940, 1.028 and 1.001, and 1.038 and 0.966, respectively. It can be concluded that the models can be used to predict egg freshness in terms of the RWL, HU, and YI at any temperature condition with in the range of 5 to 30°C during storage.

Secretion of Erythropoietin from Microencapsulated Rat Kidney Cells: Preliminary Results

Rat kidney epithelial cells were microencapsulated within alginate-poly(L)lysinealginate membrane. The microencapsulated cells were incubated using a culture media containing cobalt and another without cobalt. The viability was measured by trypan blue exclusion test. Secretion of erythropoietin (EPO) was measured by radioimmunoassay (RIA). Viability of free cells was 53%. The viability of microencapsulated cells increased to 72% after 12 days of incubation and remained at this level. Samples of the culture media were collected every 2 days for RIA. Samples within the microcapsules were collected by breaking the microcapsules open. RIA of these samples showed the following for the media containing cobalt. Between day 16 and day 32 the concentrations of EPO were 5.3 mU/ml inside and 18.3 mU/ml outside the microcapsule. The medium from the same number of free cells contained 21.2 mU/ml of EPO. Culture media without cobalt collected during the same period contained 1.8 mU/ml inside and 9.9 mU/ml outside the microcapsules. The free cell culture with this media during the same period contained 8.3 mU/ml.

Epidemiology of mental health comorbidity in psoriasis

AIM

The occurrence of mental health comorbidities such as depression, anxiety, and suicidal ideation or behavior is not uncommon in the context of psoriasis. The negative influence of psoriatic disease on a patient's physical and mental well-being, in combination with overlapping pathophysiology, increase the risk for clinically significant psychiatric conditions. These psychiatric conditions, in turn, influence the patient's outlook and potentially, prognosis. Although the healthcare community increasingly recognizes the association of mental health comorbidities with psoriasis, the extent of the correlation is not fully appreciated. To better understand the relationship between mental health comorbidities and psoriasis, including prevalence, risk factors, and response of psychiatric comorbidities to psoriasis treatment, a narrative review of the published literature was conducted.

METHODS

Data from epidemiologic, observational, and clinical studies demonstrate a substantially greater mental health comorbidity burden in patients with psoriasis compared with those without psoriasis or patients with other dermatologic conditions.

RESULT

The influence of contemporary drug therapies on measures of depression and anxiety are predominantly positive, although further data are needed to better understand the effects of long-term therapy.

CONCLUSION

Clinicians should consider the heightened potential for mental health comorbidities when determining an optimal management strategy for their patients with psoriasis.

Secukinumab in the Treatment of Psoriasis and Psoriatic Arthritis: A Review of the Literature

While there are several commercially available treatment options for psoriasis and psoriatic arthritis, there remains a large number of individuals who are refractory to current modalities. In the recent past, there has been increasing evidence that interleukin (IL)-17 plays a vital role in the pathophysiology of psoriasis. Preclinical, phase II, and phase III studies of secukinumab (Cosentyx®) targeting IL-17 and its receptor have thus far proved to be promising. We reviewed the results of phase II and phase III clinical trials for secukinumab in the treatment of psoriasis and psoriatic arthritis. Only published studies were considered in the present review. We also performed an English language literature search from January 2003 to September 2015 using PubMed with any of the following key words: (secukinumab OR AIN457) AND (psoriasis OR psoriatic arthritis). In our review of the literature, seven phase III and five phase II clinical trials, as well as open-label extension studies with unpublished findings were found. Results from phase III clinical trials indicated secukinumab to be efficacious and safe for the treatment of psoriasis and psoriatic arthritis according to Psoriasis Area and Severity Index (PASI) and American College of Rheumatology (ACR) scores. The safety profile of this agent was similar across all studies, with the most frequently reported adverse events of nasopharyngitis, upper respiratory infections, headache, and injection site reaction. Secukinumab demonstrates rapid and robust clinical improvement accompanied by a favorable short- term safety profile. The results of the phase III trials continue to reinforce the theory that the IL-17 pathway is an essential target in psoriasis and psoriatic arthritis treatment. Additional extension studies of lower level evidence are needed to further understand the safety profile of the drug.

The impact of PASI 75 and PASI 90 on quality of life in moderate to severe psoriasis patients

BACKGROUND

It is well known that psoriasis significantly impacts patients' quality of life (QoL). With the introduction of improved treatment modalities with biologic agents, more patients with moderate to severe psoriasis are able to achieve better results as measured by the Psoriasis Area and Severity Index (PASI). PASI 75 indicates a 75% or greater reduction in PASI scores from baseline and is indicative of excellent disease improvement. With newer biologic agents such as secukinumab, ixekizumab and brodalumab, patients are now capable of achieving PASI 90, introducing additional clinical decisions for physicians when considering treatment options. However, little is known regarding how the difference between achieving PASI-75 versus PASI-90 impacts patients' QoL.

OBJECTIVES

The purpose of this study was to compare how achieving PASI 75 versus PASI 90 impacts QoL for patients with moderate to severe plaque psoriasis by using validated psychometric instruments that have been widely used in both dermatologic and non-dermatologic settings.

METHODS

Two separate open-label clinical trials were conducted to specifically assess QoL in patients with moderate to severe psoriasis on adalimumab or ustekinumab over 24 weeks. In addition to clinical assessments of psoriasis, patients completed two surveys: The Psychological General Well-Being (PGWB) Index and the Dermatology Life Quality Index (DLQI). Changes in total PGWB score and DLQI score at weeks 12 and 24 compared to baseline were compared between groups achieving PASI 75 and PASI 90.

RESULTS

There was no statistically significant difference in PGWB scores between patients achieving PASI 75 and patients achieving PASI 90 in the adalimumab treatment group (week 12 p = .21, but there was at week 24 p = .05). There was a statistically significant difference in DLQI between the patients achieving PASI 75 and the patients achieving PASI 90 in the adalimumab treatment group at week 24 (p = .01), but not week 12 (p = .11). There was no statistically significant difference in PGWB scores between patients achieving PASI 75 and patients achieving PASI 90 in the ustekinumab treatment group (week 12 p = .11, week 24 p = .35). There was no statistically significant difference in DLQI between the patients achieving PASI 75 and the patients achieving PASI 90 in the ustekinumab treatment group at week 24 (week 12 p = .49, week 24 p = .11).

CONCLUSIONS

There has been tremendous attention surrounding newer biologic agents that can achieve PASI 90 and even PASI 100. Although the results are impressive with regard to physical improvement of psoriasis, there may not be a clinically significant difference in QoL when comparing patients who achieve PASI-75 versus PASI 90.

Gender Specific Differences in RNA Polymerase III Transcription

BACKGROUND

RNA polymerase (pol) III transcribes a variety of untranslated RNAs responsible for regulating cellular growth and is deregulated in a variety of cancers. In this study, we examined gender differences in RNA pol III transcription in vitro and in vivo.

METHODS

Expression levels of U6 snRNA, tMet, and known modulators of RNA pol III transcription were assayed in male and female derived adenocarcinoma (AC) lung cancer cell lines and male and female C57BL/6J mice using real time quantitative PCR. Methylation status of the U6 snRNA promoter was determined for lung and liver tissue isolated from male and female C57BL/6J mice by digesting genomic DNA with methylation sensitive restriction enzymes and digestion profiles were analyzed by qPCR using primers spanning the U6 promoter.

RESULTS

Here, we demonstrate that RNA pol III transcription is differentially regulated by EGCG in male and female derived AC lung cancer cell lines. Basal RNA pol III transcript levels are significantly different in male and female derived AC lung cancer cell lines. These data prompted an investigation of gender specific differences in RNA pol III transcription in vivo in lung and liver tissue. Herein, we report that U6 snRNA RNA pol III transcription is significantly stimulated in the liver tissue of male C57BL/6J mice. Further, the increase in U6 transcription correlates with a significant inhibition in the expression of p53, a negative regulator of RNA pol III transcription, and demethylation of the U6 promoter in the liver tissue of male C57BL/6J mice.

CONCLUSIONS

To the best of our knowledge, this is the first study demonstrating gender specific differences in RNA pol III transcription both in vivo and in vitro and further highlights the need to include both male and female cell lines and animals in experimental design.

Field-free magnetization reversal by spin-Hall effect and exchange bias

As the first magnetic random access memories are finding their way onto the market, an important issue remains to be solved: the current density required to write magnetic bits becomes prohibitively high as bit dimensions are reduced. Recently, spin–orbit torques and the spin-Hall effect in particular have attracted significant interest, as they enable magnetization reversal without high current densities running through the tunnel barrier. For perpendicularly magnetized layers, however, the technological implementation of the spin-Hall effect is hampered by the necessity of an in-plane magnetic field for deterministic switching. Here we interface a thin ferromagnetic layer with an anti-ferromagnetic material. An in-plane exchange bias is created and shown to enable field-free S HE-driven magnetization reversal of a perpendicularly magnetized Pt/Co/IrMn structure. Aside from the potential technological implications, our experiment provides additional insight into the local spin structure at the ferromagnetic/anti-ferromagnetic interface.

Future information storage technology may exploit electrical currents to write the states of ferromagnetic nanoelements via spin torque effects. Here, the authors demonstrate such behaviour promoted by exchange bias from an interfaced antiferromagnet, which may help overcome practical device limitations.

Esophageal diverticula are associated with propagating peristalsis: a study utilizing high-resolution manometry

BACKGROUND

Esophageal diverticula have been associated with esophageal motility disorders, most commonly achalasia. We aimed to evaluate high-resolution manometry (HRM) motility diagnoses and pressurization patterns in patients with esophageal diverticula.

METHODS

Patients were retrospectively identified for distal esophageal diverticula and previously completed HRM. High-resolution manometries were analyzed according to the Chicago Classification, and the pressure slope of the compartmentalization phase (time between upper esophageal sphincter closure and the transition zone) of esophageal bolus transit was measured. Pressure slopes were also measured in 10 asymptomatic volunteers (controls) for comparison.

KEY RESULTS

Nineteen patients (ages 31-83) were included. Eight (42%) patients had normal motility, five (26%) had esophagogastric junction outflow obstruction, and two (11%) had jackhammer esophagus; four patients had other motility diagnoses including only one patient with achalasia. A total of six patients (32%) had at least one hypercontractile swallow. Greater compartmentalization phase pressure slopes were observed in patients at the mid-esophageal body in both supine (median [interquartile range]: 1.9 mmHg/s [0.9, 3.6]) and upright (1.1 [0.1, 3.1]) positions than in controls (supine: -1.3 [-2.4, -0.11], p = 0.001; upright; -0.71 [-2.1, -0.02], p = 0.005).

CONCLUSIONS & INFERENCES

Propagating peristalsis, often with hypercontractility, was commonly seen in our cohort of patients with esophageal diverticula. Abnormal compartmentalization phase pressurization may indicate a relationship of abnormal esophageal wall mechanics and/or compliance with diverticula; however whether these findings are causal or reactionary remains unclear.

Oxygen-vacancy-induced orbital reconstruction of Ti ions at the interface of LaAlO3/SrTiO3 heterostructures: a resonant soft-X-ray scattering study

Resonant soft-x-ray scattering measurements have been performed to investigate interface electronic structures of (LaAlO(3)/SrTiO(3)) superlattices. Resonant scattering intensities at superlattice reflections show clear evidence of degeneracy lifting in t(2g) states of interface Ti ions. Polarization dependence of intensities indicates the energy of d(xy) states is lower by ~1 eV than two other t(2g) states. The energy splitting is insensitive to epitaxial strain. The orbital reconstruction is induced by oxygen vacancies and confined to the interface within two unit cells, indicating charge compensation at the polar interfaces.

Characterization of the PilN, PilO and PilP type IVa pilus subcomplex

Type IVa pili are bacterial nanomachines required for colonization of surfaces, but little is known about the organization of proteins in this system. The Pseudomonas aeruginosa pilMNOPQ operon encodes five key members of the transenvelope complex facilitating pilus function. While PilQ forms the outer membrane secretin pore, the functions of the inner membrane-associated proteins PilM/N/O/P are less well defined. Structural characterization of a stable C-terminal fragment of PilP (PilP(Δ71)) by NMR revealed a modified β-sandwich fold, similar to that of Neisseria meningitidis PilP, although complementation experiments showed that the two proteins are not interchangeable likely due to divergent surface properties. PilP is an inner membrane putative lipoprotein, but mutagenesis of the putative lipobox had no effect on the localization and function of PilP. A larger fragment, PilP(Δ18-6His), co-purified with a PilN(Δ44)/PilO(Δ51) heterodimer as a stable complex that eluted from a size exclusion chromatography column as a single peak with a molecular weight equivalent to two heterotrimers with 1:1:1 stoichiometry. Although PilO forms both homodimers and PilN-PilO heterodimers, PilP(Δ18-6His) did not interact stably with PilO(Δ51) alone. Together these data demonstrate that PilN/PilO/PilP interact directly to form a stable heterotrimeric complex, explaining the dispensability of PilP's lipid anchor for localization and function.

Evaluation of fibrinogen self-assembly: role of its αC region

BACKGROUND

Exposure of cryptic, functional sites on fibrinogen upon its adsorption to hydrophobic surfaces of biomaterials has been linked to an inflammatory response and fibrosis. Such adsorption also induces ordered fibrinogen aggregation which is poorly understood.

OBJECTIVE

To investigate hydrophobic surface-induced fibrinogen aggregation.

METHODS

Contact and lateral force scanning probe microscopy, yielding topography, image dimensions and fiber elastic modulus measurements were used along with transmission and scanning electron microscopy. Fibrinogen aggregation was induced under non-enzymatic conditions by adsorption on a trioctyl-surface monolayer (trioctylmethylamine) grafted onto silica clay plates.

RESULTS

A more than one molecule thick coating was generated by adsorption on the plate from 100 to 200 μg mL⁻¹ fibrinogen solutions, and three-dimensional networks formed from 4 mg mL⁻¹ fibrinogen incubated with uncoated or fibrinogen-coated plates. Fibrils appeared laterally assembled into branching and overlapping fibers whose heights from the surface ranged from approximately 3 to 740 nm. The elastic modulus of fibrinogen fibers was 1.55 MPa. No fibrils formed when fibrinogen lacking αC-domains was used as a coating or was incubated with intact fibrinogen-coated plates, or when the latter plates were sequentially incubated with anti-Aα529-539 mAb and intact fibrinogen. When an anti-Aα241-476 mAb was used instead, fine, long fibers formed. Similarly, sequential incubations of fibrinogen-coated plates with recombinant αC-domain (Aα392-610 fragment) or αC-connector (Aα221-372 fragment) and fibrinogen resulted in distinctly fine fiber networks.

CONCLUSIONS

Adsorption-induced fibrinogen self-assembly is initiated by a more than one molecule-thick surface layer and eventuates in three-dimensional networks whose formation requires fibrinogen with intact αC-domains.

Reduced viscosity of the free surface in entangled polymer melt films

By embedding "dilute" gold nanoparticles in single polystyrene thin films as "markers", we probe the local viscosity of the free surface at temperatures far above the glass transition temperature (T(g)). The technique used was x-ray photon correlation spectroscopy with resonance-enhanced x-ray scattering. The results clearly showed the surface viscosity is about 30% lower than the rest of the film. We found that this reduction is strongly associated with chain entanglements at the free surface rather than the reduction in T(g).

PilM/N/O/P proteins form an inner membrane complex that affects the stability of the Pseudomonas aeruginosa type IV pilus secretin

The highly conserved pilM/N/O/P/Q gene cluster is among the core set of genes required for cell surface expression of type IV pili and associated twitching motility. With the exception of the outer membrane secretin, a multimer of PilQ subunits, the specific functions of the products encoded by this gene cluster are poorly characterized. Orthologous proteins in the related bacterial type II secretion system have been shown to interact to form an inner membrane complex required for protein secretion. In this study, we provide evidence that the PilM/N/O/P proteins form a functionally equivalent type IVa pilus complex. Using Pseudomonas aeruginosa as model organism, we found that all four proteins, including the nominally cytoplasmic PilM, colocalized to the inner membrane. Stability studies via Western blot analyses revealed that loss of one component has a negative impact on the levels of other members of the putative complex. Furthermore, complementation studies revealed that the stoichiometry of the components is important for the correct formation of a stable complex in vivo. We provide evidence that an intact inner membrane complex is required for optimal formation of the outer membrane complex of the type IVa pilus system in P. aeruginosa, as PilQ stability is negatively affected in its absence. Finally, we show that, in the absence of the pilin subunit, the levels of membrane-bound components of the inner membrane complex are negatively regulated by the PilR/S two-component system, suggesting a role for PilR/S in sensing the piliation status of the cell.

Periplasmic domains of Pseudomonas aeruginosa PilN and PilO form a stable heterodimeric complex

Type IV pili (T4P) are bacterial virulence factors responsible for attachment to surfaces and for twitching motility, a motion that involves a succession of pilus extension and retraction cycles. In the opportunistic pathogen Pseudomonas aeruginosa, the PilM/N/O/P proteins are essential for T4P biogenesis, and genetic and biochemical analyses strongly suggest that they form an inner-membrane complex. Here, we show through co-expression and biochemical analysis that the periplasmic domains of PilN and PilO interact to form a heterodimer. The structure of residues 69-201 of the periplasmic domain of PilO was determined to 2.2 A resolution and reveals the presence of a homodimer in the asymmetric unit. Each monomer consists of two N-terminal coiled coils and a C-terminal ferredoxin-like domain. This structure was used to generate homology models of PilN and the PilN/O heterodimer. Our structural analysis suggests that in vivo PilN/O heterodimerization would require changes in the orientation of the first N-terminal coiled coil, which leads to two alternative models for the role of the transmembrane domains in the PilN/O interaction. Analysis of PilN/O orthologues in the type II secretion system EpsL/M revealed significant similarities in their secondary structures and the tertiary structures of PilO and EpsM, although the way these proteins interact to form inner-membrane complexes appears to be different in T4P and type II secretion. Our analysis suggests that PilN interacts directly, via its N-terminal tail, with the cytoplasmic protein PilM. This work shows a direct interaction between the periplasmic domains of PilN and PilO, with PilO playing a key role in the proper folding of PilN. Our results suggest that PilN/O heterodimers form the foundation of the inner-membrane PilM/N/O/P complex, which is critical for the assembly of a functional T4P complex.

Expression of androgen receptors in primary breast cancer

BACKGROUND

To investigate the clinicopathological significance of androgen receptor (AR) expression in primary breast cancers.

PATIENTS AND METHODS

We evaluated AR using immunohistochemistry from 413 whole sections from January 2008 to March 2009 and analyzed the relationship between AR and clinicopathological parameters. Tumors with >/=10% nuclear-stained cells were considered to be positive for AR. The differences among variables were calculated by chi-square test.

RESULTS

The expression rate of AR was 72.9% higher than those of estrogen receptors (ER) and progesterone receptors. AR expression was significant in patients with no elevated preoperative serum cancer antigen 15-3 levels, smaller tumor size, lower histologic grade and hormone receptor-positive and non-triple-negative breast cancer. However, AR expression was observed in 35% of triple-negative cancers. Metaplastic, medullary and mucinous types of carcinomas showed less AR expression. In the ER-negative subgroup, AR was significantly correlated with human epidermal growth factor receptor type 2 (HER-2) overexpression.

CONCLUSIONS

AR is expressed in a significant number of breast cancers and is associated with lower tumor burden and favorable differentiation. There are many issues to be further investigated such as whether AR is an independent prognostic factor, whether it is a therapeutic target for the triple-negative breast cancers and whether it is associated with HER-2 signaling in ER-negative tumors.