Functional characterisation of Artemisia annua jasmonic acid carboxyl methyltransferase: a key enzyme enhancing artemisinin biosynthesis.

MAIN CONCLUSION: Overexpression of Artemisia annua jasmonic acid carboxyl methyltransferase (AaJMT) leads to enhanced artemisinin content in Artemisia annua. Artemisinin-based combination therapies remain the sole deterrent against deadly disease malaria and Artemisia annua remains the only natural producer of artemisinin. In this study, the 1101 bp gene S-adenosyl-L-methionine (SAM): Artemisia annua jasmonic acid carboxyl methyltransferase (AaJMT), was characterised from A. annua, which converts jasmonic acid (JA) to methyl jasmonate (MeJA). From phylogenetic analysis, we confirmed that AaJMT shares a common ancestor with Arabidopsis thaliana, Eutrema japonica and has a close homology with JMT of Camellia sinensis. Further, the Clustal Omega depicted that the conserved motif I, motif III and motif SSSS (serine) required to bind SAM and JA, respectively, are present in AaJMT. The relative expression of AaJMT was induced by wounding, MeJA and salicylic acid (SA) treatments. Additionally, we found that the recombinant AaJMT protein catalyses the synthesis of MeJA from JA with a Km value of 37.16 µM. Moreover, site-directed mutagenesis of serine-151 in motif SSSS to tyrosine, asparagine-10 to threonine and glutamine-25 to histidine abolished the enzyme activity of AaJMT, thus indicating their determining role in JA substrate binding. The GC-MS analysis validated that mutant proteins of AaJMT were unable to convert JA into MeJA. Finally, the artemisinin biosynthetic and trichome developmental genes were upregulated in AaJMT overexpression transgenic lines, which in turn increased the artemisinin content.

Design of a Bilateral Disulfurating Reagent for Unsymmetrical Polysulfidation.

In this study, we designed a bilateral disulfurating reagent via S-S motif "snip and stitch" processes, allowing diverse functional groups to be bridged via S-S bonds. The reagent is readily synthesized in high yield using a one-step reaction from easily available starting materials and is air-stable. With this reagent, diverse electrophiles including inactivated alkyl Cl/Br/I/OMs and benzyl chloride were sequentially installed on either side of the S-S motif. Natural products, agrochemicals, and pharmaceuticals can be successively cross-linked with S-S bonds. Notably, the disulfurating reagent can be used in cyclic disulfide synthesis. At last, some desired products of this work showed good antibacterial activities, which could be employed as novel candidates to control plant pathogenic bacteria.

RDb2C2: an improved method to identify the residue-residue pairing in ß strands.

BACKGROUND: Despite the great advance of protein structure prediction, accurate prediction of the structures of mainly ß proteins is still highly challenging, but could be assisted by the knowledge of residue-residue pairing in ß strands. Previously, we proposed a ridge-detection-based algorithm RDb2C that adopted a multi-stage random forest framework to predict the ß-ß pairing given the amino acid sequence of a protein. RESULTS: In this work, we developed a second version of this algorithm, RDb2C2, by employing the residual neural network to further enhance the prediction accuracy. In the benchmark test, this new algorithm improves the F1-score by > 10 percentage points, reaching impressively high values of ~ 72% and ~ 73% in the BetaSheet916 and BetaSheet1452 sets, respectively. CONCLUSION: Our new method promotes the prediction accuracy of ß-ß pairing to a new level and the prediction results could better assist the structure modeling of mainly ß proteins. We prepared an online server of RDb2C2 at http://structpred.life.tsinghua.edu.cn/rdb2c2.html.

Antibiotic sensitivity and clinical outcomes in staphylococcal scalded skin syndrome.

Staphylococcal scalded skin syndrome causes widespread skin denudation primarily in infants < 1 year old. Selection of empiric therapy is complicated by rising rates of antibiotic resistance in community-acquired staphylococcal infections. Consistent with a previous study, this retrospective review found that SSSS-associated isolates were more likely to be clindamycin-resistant and less likely to be methicillin-resistant compared to overall staphylococcal infections. We favor cephalosporins and penicillinase-resistant penicillins (eg, oxacillin) for empiric management of SSSS, with consideration of adding MRSA coverage in communities with high MRSA prevalence or failure to improve following several days of treatment.

Identification of residue pairing in interacting ß-strands from a predicted residue contact map.

BACKGROUND: Despite the rapid progress of protein residue contact prediction, predicted residue contact maps frequently contain many errors. However, information of residue pairing in ß strands could be extracted from a noisy contact map, due to the presence of characteristic contact patterns in ß-ß interactions. This information may benefit the tertiary structure prediction of mainly ß proteins. In this work, we propose a novel ridge-detection-based ß-ß contact predictor to identify residue pairing in ß strands from any predicted residue contact map. RESULTS: Our algorithm RDb2C adopts ridge detection, a well-developed technique in computer image processing, to capture consecutive residue contacts, and then utilizes a novel multi-stage random forest framework to integrate the ridge information and additional features for prediction. Starting from the predicted contact map of CCMpred, RDb2C remarkably outperforms all state-of-the-art methods on two conventional test sets of ß proteins (BetaSheet916 and BetaSheet1452), and achieves F1-scores of ~ 62% and ~ 76% at the residue level and strand level, respectively. Taking the prediction of the more advanced RaptorX-Contact as input, RDb2C achieves impressively higher performance, with F1-scores reaching ~ 76% and ~ 86% at the residue level and strand level, respectively. In a test of structural modeling using the top 1 L predicted contacts as constraints, for 61 mainly ß proteins, the average TM-score achieves 0.442 when using the raw RaptorX-Contact prediction, but increases to 0.506 when using the improved prediction by RDb2C. CONCLUSION: Our method can significantly improve the prediction of ß-ß contacts from any predicted residue contact maps. Prediction results of our algorithm could be directly applied to effectively facilitate the practical structure prediction of mainly ß proteins. AVAILABILITY: All source data and codes are available at http://166.111.152.91/Downloads.html or the GitHub address of https://github.com/wzmao/RDb2C .

Atorvastatin Calcium Inhibits PDGF-ßß-Induced Proliferation and Migration of VSMCs Through the G0/G1 Cell Cycle Arrest and Suppression of Activated PDGFRß-PI3K-Akt Signaling Cascade.

BACKGROUND/AIMS: Abnormal proliferation of vascular smooth muscle cells (VSMCs) is a hallmark of vascular lesions, such as atherosclerosis and restenosis. PDGF-ßß, an isoform of PDGF (platelet-derived growth factor), has been demonstrated to induce proliferation and migration of VSMCs. Atorvastatin calcium, a selective inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, has favorable protective effects on VSMCs. This study examined the effects of atorvastatin calcium on the proliferation and migration of PDGF-ßß-treated VSMCs, as well as its underlying mechanisms. METHODS: MTT assays, Edu imaging, cell cycle analysis, wound healing assays, transwell migration assays, and western blot analysis were performed. RESULTS: Atorvastatin calcium significantly inhibited cell proliferation, DNA synthesis and cell migration of PDGF-ßß-treated VSMCs. We demonstrated that atorvastatin calcium induced cell cycle arrest in the G0/G1 phase in response to PDGF-ßß stimulation and decreased the expression of G0/G1-specific regulatory proteins, including proliferating cell nuclear antigen (PCNA), CDK2, cyclin D1, cyclin E and CDK4 in PDGF-ßß-treated VSMCs. Moreover, pretreatment with atorvastatin calcium inhibited the PDGF-ßß-treated phosphorylation of PDGFRß and Akt, whereas atorvastatin calcium did not affect the phosphorylation of PLC-γ1 or (ERK) 1/2. CONCLUSION: Our data suggested that atorvastatin calcium inhibited abnormal proliferation and migration of VSMCs through G0/G1 cell cycle arrest and suppression of the PDGFRß-Akt signaling cascade.

The Clinical Characteristics and Antimicrobial Resistance of Staphylococcus aureus Isolated from Patients with Staphylococcal Scalded Skin Syndrome (SSSS) in Southwestern China.

Staphylococcal scalded skin syndrome (SSSS) is a rare, toxin-mediated, desquamating bacterial infectious dermatosis. So far, data from Southwestern China is scarce. This study aimed to investigate the clinical characteristics of SSSS patients in our hospital, the relative proportion of methicillin-resistant Staphylococcus aureus (MRSA) in skin and soft tissue secretions, and the drug sensitivity of S. aureus to better assist dermatologists in the diagnosis and treatment of SSSS. We reviewed the demographic characteristics, clinical manifestations, treatment regimens, therapeutic efficacy, laboratory test results, drug sensitivity, and outcome data of 79 SSSS patients from January 2012 to December 2021. Statistical analysis was performed using t tests and chi-square tests. Among the 79 SSSS patients, MRSA was detected in 35 (44.3%) isolates: 34 community-acquired (CA)-MRSA (97.1%) and 1 hospital-acquired (HA)-MRSA. The SSSS incidence increased annually from 2012 to 2014 and then decreased gradually after peaking in 2015. All the isolates were sensitive to vancomycin, tigecycline, linezolid, moxifloxacin, levofloxacin, and ciprofloxacin; were completely resistant to penicillin; and had low sensitivity to clindamycin and erythromycin. Interestingly, the sensitivity of MRSA to tetracycline increased annually after 2015. The resistance rates to common drugs previously used to treat SSSS increased. These findings may accelerate diagnosis and improve empirical antibiotic use, suggesting that clinicians should prescribe drugs according to antimicrobial susceptibility.

Toxic epidermal necrolysis: Part II. Prognosis, sequelae, diagnosis, differential diagnosis, prevention, and treatment.

Toxic epidermal necrolysis (TEN) is a life-threatening, typically drug-induced, mucocutaneous disease. TEN has a high mortality rate, making early diagnosis and treatment of paramount importance. New but experimental diagnostic tools that measure serum granulysin and high-mobility group protein B1 (HMGB1) offer the potential to differentiate early TEN from other, less serious drug reactions, but these tests have not been validated and are not readily available. The mainstay of treatment for TEN involves discontinuation of the offending drug, specialized care in an intensive care unit or burn center, and supportive therapy. Pharmacogenetic studies have clearly established a link between human leukocyte antigen allotype and TEN. Human leukocyte antigen testing should be performed on patients of East Asian descent before the initiation of carbamezapine and on all patients before the initiation of abacavir. The effectiveness of systemic steroids, intravenous immunoglobulins, plasmapheresis, cyclosporine, biologics, and other agents is uncertain.

Congenital staphylococcal scalded skin syndrome in a preterm infant.

Staphylococcal scalded skin syndrome (SSSS) is a rare condition in premature infants. We report a case of SSSS in a preterm neonate who displayed all clinical manifestations at birth, leading to a fatal outcome from Candida parapsilosis fungemia. The clinical presentation was challenging to differential diagnosis. SSSS diagnosis was confirmed by skin biopsy. This case emphasizes the significance of early recognition and diagnosis of SSSS promptly for clinicians. Congenital SSSS in premature infants can be fatal, but with early recognition and appropriate supportive and antimicrobial therapy, outcomes can be improved and lives can be saved.

TEN mimics: Classification and practical approach to toxic epidermal necrolysis-like dermatoses.

Toxic epidermal necrolysis (TEN) is an acute life-threatening dermatologic emergency. However, many dermatoses can present with a TEN-like eruption. Those "TEN-mimics" are a true diagnostic challenge and an alarming differential diagnosis to such a serious condition. Herein, we will expose and classify the landscape of TEN-mimics. Also, the key differentiating clinical and/or laboratory points will be highlighted to help an accurate diagnosis of either a TEN or a TEN-like presentation.

Initial Stage of Syringyl Lignin Formation from Sinapyl Alcohol.

Elucidating the detailed structure and formation mechanism of lignin, especially understudied syringyl (S) lignin, advances our knowledge of lignocellulosic biomass. To examine the early stages of S-lignin formation from sinapyl alcohol (SA), the FMR (flow microreactor) method and the Zutropf (gradual addition of SA) method with limited amounts of H2O2 were employed for the peroxidase-catalyzed dehydrogenative polymerization of SA. Only ß-ß dimers and not ß-O-4 dimers were obtained as initial dimerization products. Six new oligoligognols up to pentamers with ß-ß and ß-O-4 structures were identified. The erythro isomer was preferentially formed over the threo isomer in the ß-O-4 structures, similar to that found in naturally occurring S-rich hardwood lignin. Although minor substructures, the α-oxidized ß-ß and ß-O-4 structures and spirodienone (ß-1) structure identified in this study demonstrate the characteristic features of S-rich lignin. Based on the identified products, the initial formation mechanism of S-lignin from SA was proposed.

Predominance of community-associated, methicillin-susceptible Staphylococcus aureus infections among hospitalized children and adolescents.

Introduction. Staphylococcus aureus infections cause significant morbidity and mortality in children and adolescents.Gap Statement. There is limited data on the characteristics of S. aureus infections requiring hospitalization in childhood.Aim.To investigate the molecular epidemiology and antibiotic resistance of S. aureus clinical isolates from children and adolescents.Methodology.All S. aureus isolates recovered from patients aged <18 years, admitted to a referral hospital, with culture-proven invasive or non-invasive infections during the 4 year period 2015 to 2018 were analysed for antimicrobial resistance, virulence genes, PFGE and multilocus sequence typing (MLST). Cases were assigned to community-associated, community-onset healthcare-associated or hospital-associated infections based on epidemiological case definitions.Results.Among 139 S. aureus infections, 88.5 % (123/139) were caused by methicillin-susceptible isolates (MSSA) and 73.4 % (102/139) were classified as community-associated infections. tst and lukS/lukF-PV genes were more common among MRSA as compared to MSSA isolates (tst, p 0.04; lukS/lukF-PV, p 0.007). Invasive disease was noted in 22/139 patients (15.8 %). Staphylococcal scalded skin syndrome caused by fusidic-resistant MSSA increased over time (22.8 % in 2017-2018 vs 8.3 % in 2015-2016, OR 3.24; 95 % CI 1.10-8.36; P 0.03). By PFGE genotyping, 22 pulsotypes were identified. A total of five sequence types (STs) were identified among 58 isolates analysed by MLST. More than one third of MSSA isolates (40/123, 32.5 %) and 13/23 (56.5 %) of SSSS isolates belonged to pulsotype 1, classified as sequence type 121 (ST121). MRSA isolates were equally distributed to pulsotypes A (ST30), B (ST239), C (ST80), H (ST225). ST121 isolates carried fnbA (40/40), eta/etb genes (29/40), exhibited high resistance to fusidic acid and were increasingly resistant to mupirocin.Conclusion.In our population, community-associated MSSA was the predominant cause of S. aureus infections characterized by polyclonality, increasing resistance to fusidic acid and mupirocin. PFGE type 1 ST121 clone, harboured exfoliative toxin genes and was associated with rising trends of SSSS.

Evidence and Potential Mechanism of Action of Lithospermum erythrorhizon and Its Active Components for Psoriasis.

Background: Traditional Chinese medicine is effective in the treatment of psoriasis and can significantly reduce skin inflammation and psoriatic lesions with minimal side effects. Shikonin (SHI) and ß,ß-dimethylacryloyl alkannin (DMA), the main active components of Lithospermum erythrorhizon, have strong anti-inflammatory effects. This systematic review aimed to evaluate the efficacy and safety of Lithospermum erythrorhizon and its main active components and to elucidate the potential mechanisms of their action in psoriasis treatment. Methods: PubMed, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, Chinese Scientific Journals, Wan Fang, and Chinese Biomedicine databases were systematically searched for articles published between 1 January 1970, and 31 February 2021. We included clinical and preclinical studies that examined the effects of Lithospermum erythrorhizon and its active components on psoriasis. All data were analyzed using RevMan 5.3 software. The Cochrane and SYRCLE's risk-of-bias tools were used to assess the quality of all studies. Results: Eleven clinical trials including 1024 participants and 23 preclinical studies were assessed. Meta-analysis showed that when treating patients with psoriasis, the Chinese herbal medicine (CHM) formulas with Lithospermum erythrorhizon as the sovereign herb can significantly improve psoriatic dermatitis, which can significantly reduce the psoriasis area and severity index (PASI) score (mean difference [MD] = -2.00, 95% confidence interval [CI] [-3.19, -0.80], p = 0.001; I2 = 85%). The incidence rates of diarrhea (risk ratio = 0.21, 95% CI [0.06, 0.81], p = 0.02) were higher in the CHM formulas group than in the control group, whereas other adverse events were not significantly different between the two groups (p > 0.05). We evaluated the PASI score of mice on day 7 and found that SHI and DMA also alleviated psoriatic lesions (MD = -3.36, 95% CI [-4.67, -2.05], p < 0.00001, I2 = 94%). Furthermore, the epidermal thickness decreased more after SHI or DMA treatment than in the control group (MD = -34.42, 95%CI [-41.25, -27.59], p < 0.00001, I2 = 93%). Based on preclinical studies, we also summarized and mapped the mechanisms of SHI and DMA in the treatment of psoriasis. Conclusion: Available findings demonstrated that Lithospermum erythrorhizon combined with other conventional treatments is useful in treating psoriasis. Preclinical evidence has shown that the active components of Lithospermum erythrorhizon exhibit a potential anti-inflammatory effect, promote keratinocyte apoptosis, inhibit keratinocyte proliferation and angiogenesis, and block the cell cycle. In summary, our findings suggest that Lithospermum erythrorhizon and its active components can be used to treat psoriasis.

How to Deal with Skin Biopsy in an Infant with Blisters?

The onset of blisters in a neonate or an infant is often a source of great concern for both parents and physicians. A blistering rash can reveal a wide range of diseases with various backgrounds (infectious, genetic, autoimmune, drug-related, traumatic, etc.), so the challenge for the dermatologist and the pediatrician is to quickly determine the etiology, between benign causes and life-threatening disorders, for a better management of the patient. Clinical presentation can provide orientation for the diagnosis, but skin biopsy is often necessary in determining the cause of blister formations. In this article, we will provide information on the skin biopsy technique and discuss the clinical orientation in the case of a neonate or infant with a blistering eruption, with a focus on the histology for each etiology.

The Role of Gram Staining in Staphylococcal Scalded Skin Syndrome.

Staphylococcal scalded skin syndrome (SSSS) is a severe blistering disease common in children. The diagnosis of SSSS is often difficult to distinguish from other blistering diseases in children. Here, we report a case of SSSS with a particular diagnostic step to elucidate the disease, which is the Gram stain. We propose the use of the Gram stain as a cost-effective diagnostic step in SSSS to shorten the time from presentation to treatment, especially in resource-limited areas.

The influence of mitochondrial-directed regulation of Wnt signaling on tumorigenesis.

Mitochondria are dynamic organelles that play a key role in integrating cellular signaling. Mitochondrial alterations are evident in all stages of tumorigenesis and targeting mitochondrial pathways has emerged as an anticancer therapeutic strategy. The Wnt-signaling pathway regulates many fundamental cellular functions such as proliferation, survival, migration, stem-cell maintenance, and mitochondrial metabolism and dynamics. Emerging evidence demonstrates that mitochondrial-induced regulation of Wnt signaling provides an additional mechanism to influence cell-fate decisions. Crosstalk between mitochondria and Wnt signaling presents a feedforward loop in which Wnt activation regulates mitochondrial function that, in turn, drives Wnt signaling. In this mini-review, we will discuss the recent evidence revealing the mitochondrial control of Wnt signaling and its implications for tumorigenesis and anticancer therapeutic targeting.

Staphylococcal scalded skin syndrome in a 4-year-old child: a case report.

BACKGROUND: Staphylococcal scalded skin syndrome is an exfoliating skin disease which primarily affects children. Differential diagnosis includes toxic epidermal necrolysis, staphylococcal scalded skin syndrome, epidermolysis bullosa, and Stevens-Johnson syndrome. Staphylococcal scalded skin syndrome primarily affects children and can cause serious morbidity. CASE PRESENTATION: In this case report we highlight the case of a 4-year-old Caucasian boy. Diagnostic and therapeutic challenges are discussed. Differential diagnoses are considered and therapy is described and discussed. The latest treatment options are used and described. Successful results are achieved in this case due to timely and correct management. CONCLUSIONS: Some therapeutic options are widely used without thorough research bases. This case report highlights staphylococcal scalded skin syndrome and its treatment, and future challenges. Further research is warranted and this case report aims to further research in exfoliating skin disorders.

Staphylococcal scalded skin syndrome: An uncommon symptomatology revealing an immune deficiency.

Primary immune deficiencies associated with hyper-IgE syndrome are rare diseases with clinical features dominated by recurring cutaneous and visceral bacterial infections, particularly infections due to Staphylococcus species. Most of these infections are associated with milder inflammation compared to normal. We report a primary immune deficiency associated with a hyper-IgE syndrome revealed by a staphylococcal scalded skin syndrome in a 5-year-old girl. The patient presented with a severe staphylococcal infection with extensive skin lesions and disseminated intravascular coagulation. She received intravenous fluids to compensate for fluid losses and anti-staphylococcal antibiotics. Coagulopathy was also corrected. However, the progression was rapidly fatal.

PKU mutation p.G46S prevents the stereospecific binding of l-phenylalanine to the dimer of human phenylalanine hydroxylase regulatory domain.

Mammalian phenylalanine hydroxylase (PAH) has a potential allosteric regulatory binding site for l-phenylalanine (l-Phe), in addition to its catalytic site. This arrangement is supported by a crystal structure of a homodimeric truncated form of the regulatory domain of human PAH (hPAH-RD 1-118/19-118) [Patel D et al. (2016) Sci Rep doi: 10.1038/srep23748]. In this study, a fusion protein of the domain (MBP-(pepXa)-hPAH-RD 1-120) was overexpressed and recovered in a metastable and soluble state, which allowed the isolation of a dimeric and a monomeric fusion protein. When cleaved from MBP, hPAH-RD forms aggregates which are stereospecifically inhibited by l-Phe (> 95%) at low physiological concentrations. Aggregation of the cleaved dimer of the mutant form hPAH-G46S-RD was not inhibited by l-Phe, which is compatible with structurally/conformationally changed ßαßßαß ACT domain folds in the mutant.

Severe case of staphylococcal scalded skin syndrome in a 5-year-old child - case report.

Benign impetigo can progress into a potential fatal staphylococcal scalded skin syndrome (SSSS) if prompt diagnosis and correct therapy is not established rapidly. Local and systematic antibiotics as well as Lactulose are crucial in order to stop SSSS from progressing. Burns units should be involved when skin lesions are extensive.