Characterization of a cytokinin-binding protein locus in Mycobacterium tuberculosis.

Cytokinins are adenine-based hormones that have been well-characterized in plants but are also made by bacteria, including the human-exclusive pathogen Mycobacterium tuberculosis . In M. tuberculosis , cytokinins activate transcription of an operon that affects the bacterial cell envelope. In plants, cytokinins are broken down by dedicated enzymes called cytokinin oxidases into adenine and various aldehydes. In proteasome degradation-deficient M. tuberculosis , the cytokinin-producing enzyme Log accumulates, resulting in the buildup of at least one cytokinin-associated aldehyde. We therefore hypothesized that M. tuberculosis encodes one or more cytokinin oxidases. Using a homology-based search for homologs of a plant cytokinin oxidase, we identified Rv3719 and a putative cytokinin-specific binding protein, Rv3718c. Deletion of the locus encoding these proteins did not have a measurable effect on in vitro growth. Nonetheless, Rv3718c bound a cytokinin with high specificity. Our data thus support a model whereby cytokinins play one or more roles in mycobacterial physiology. IMPORTANCE: Numerous bacterial species encode cytokinin-producing enzymes, the functions of which are almost completely unknown. This work contributes new knowledge to the cytokinin field for bacteria, and also revealed further conservation of cytokinin-associated proteins between plants and prokaryotes.

Identification of a proteolysis regulator for an essential enzyme in Mycobacterium tuberculosis.

In Mycobacterium tuberculosis proteins that are post-translationally modified with Pup, a prokaryotic ubiquitin-like protein, can be degraded by proteasomes. While pupylation is reversible, mechanisms regulating substrate specificity have not been identified. Here, we identify the first depupylation regulators: CoaX, a pseudokinase, and pantothenate, an essential, central metabolite. In a Δ coaX mutant, pantothenate synthesis enzymes were more abundant, including PanB, a substrate of the Pup-proteasome system. Media supplementation with pantothenate decreased PanB levels in a coaX and Pup-proteasome-dependent manner. In vitro , CoaX accelerated depupylation of Pup∼PanB, while addition of pantothenate inhibited this reaction. Collectively, we propose CoaX contributes to proteasomal degradation of PanB by modulating depupylation of Pup∼PanB in response to pantothenate levels. One Sentence Summary: A pseudo-pantothenate kinase regulates proteasomal degradation of a pantothenate synthesis enzyme in M. tuberculosis .

AGEs Blocker™ (Goji Berry, Fig, and Korean Mint Mixed Extract) Inhibits Skin Aging Caused by Streptozotocin-Induced Glycation in Hairless Mice.

Glycation is a cause of skin aging. This study investigated in a glycation-induced skin aging mouse model the effects on skin and mechanism of action of AGEs Blocker™ (AB), which contains goji berry, fig, and Korean mint mixed extract. This study sought to demonstrate the antiglycation effect of streptozotocin, thereby improving skin aging, by measuring advanced glycation end products (AGEs) and various skin parameters, including collagen; matrix metalloproteinases (MMPs); inflammatory cytokines; activities of oxidative enzymes; and skin wrinkles, elasticity, and hydration. This study found that skin wrinkles, elasticity, and hydration improved with AB. Particularly, the oral administration of AB suppressed AGEs, receptors of AGEs, and carboxymethyl lysine in blood and skin tissue. In addition, AB increased the activities of antioxidative enzymes, reduced inflammatory cytokines, suppressed MMP-9 expression, and increased the contents of collagen and hyaluronic acid, ultimately suppressing skin wrinkles and increasing skin elasticity and hydration. Therefore, AB can inhibit skin aging through its antiglycation effect and is thus considered a good ingredient for skin care products.

Development of a selective medium for the enumeration of lactic acid bacteria and bifidobacteria in food products.

This study was conducted to develop a selective medium for enumerating LAB and Bifidobacteria in food samples. Thirteen media were evaluated to determine their suitability for selectively enumerating LAB (17 bacilli and 7 cocci) and Bifidobacteria (12 strains) under aerobic and anaerobic conditions. When BL, BCP, and mMRS were supplemented with propionic acid (5 ml/l) and adjusted to pH 5, the growth of all indicator microorganisms was inhibited; however, these media also inhibited the growth of certain LAB and Bifidobacterial strains. Using propionic acid, the pH levels of BL, BCP, and mMRS were adjusted to pH 5.2, 6.0, and 6.0, respectively. These media inhibited the growth of all indicator microorganisms, whereas they did not inhibit any of the LAB and Bifidobacteria strains under anaerobic conditions. Overall, BLP (pH 5.8) lacking blood showed significantly higher bacterial counts compared with other media in food products. Further analyses indicated that BLP (pH 5.8) was the most suitable medium for enumerating LAB and Bifidobacteria in food. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01202-z.

A conserved loop sequence of the proteasome system depupylase Dop regulates substrate selectivity in Mycobacterium tuberculosis.

Mycobacteria use a proteasome system that is similar to a eukaryotic proteasome but do not use ubiquitin to target proteins for degradation. Instead, mycobacteria encode a prokaryotic ubiquitin-like protein (Pup) that posttranslationally modifies proteins to mark them for proteolysis. Pupylation occurs on lysines of targeted proteins and is catalyzed by the ligase PafA. Like ubiquitylation, pupylation can be reversed by the depupylase Dop, which shares high structural similarity with PafA. Unique to Dop near its active site is a disordered loop of approximately 40 amino acids that is highly conserved among diverse dop-containing bacterial genera. To understand the function of this domain, we deleted discrete sequences from the Dop loop and assessed pupylation in mutant strains of Mycobacterium tuberculosis. We determined that various Dop loop mutations resulted in altered pupylome profiles, in particular when mutant dop alleles were overexpressed. Taken together, our data suggest these conserved amino acids play a role in substrate selectivity for Dop.

The ß-Grasp Domain of Proteasomal ATPase Mpa Makes Critical Contacts with the Mycobacterium tuberculosis 20S Core Particle to Facilitate Degradation.

Mycobacterium tuberculosis possesses a Pup-proteasome system analogous to the eukaryotic ubiquitin-proteasome pathway. We have previously shown that the hexameric mycobacterial proteasome ATPase (Mpa) recruits pupylated protein substrates via interactions between amino-terminal coiled-coils in Mpa monomers and the degradation tag Pup. However, it is unclear how Mpa rings interact with a proteasome due to the presence of a carboxyl-terminal ß-grasp domain unique to Mpa homologues that makes the interaction highly unstable. Here, we describe newly identified critical interactions between Mpa and 20S core proteasomes. Interestingly, the Mpa C-terminal GQYL motif binds the 20S core particle activation pocket differently than the same motif of the ATP-independent proteasome accessory factor PafE. We further found that the ß-hairpin of the Mpa ß-grasp domain interacts variably with the H0 helix on top of the 20S core particle via a series of ionic and hydrogen-bond interactions. Individually mutating several involved residues reduced Mpa-mediated protein degradation both in vitro and in vivo. IMPORTANCE The Pup-proteasome system in Mycobacterium tuberculosis is critical for this species to cause lethal infections in mice. Investigating the molecular mechanism of how the Mpa ATPase recruits and unfolds pupylated substrates to the 20S proteasomal core particle for degradation will be essential to fully understand how degradation is regulated, and the structural information we report may be useful for the development of new tuberculosis chemotherapies.

Metformin ameliorates scleroderma via inhibiting Th17 cells and reducing mTOR-STAT3 signaling in skin fibroblasts.

Scleroderma is an autoimmune disease that causes dermal fibrosis. It occurs when collagen accumulates in tissue as a result of persistent inflammation. Th17 cells and pro-inflammatory cytokines such as IL-1ß, IL-6, IL-17, and TNF-α play important roles in the pathogenesis of scleroderma. Because metformin, a medication used to treat diabetes, has effective immunoregulatory functions, we investigated its therapeutic function in scleroderma. Mice in a model of bleomycin-induced scleroderma were treated with metformin for 2 weeks. Histological assessment demonstrated protective effects of metformin against scleroderma. Metformin decreased the expression of pro-inflammatory factors in dermal tissue and lymphocytes. It also decreased mRNA expression of pro-inflammatory cytokines (IL-1ß, IL-6, IL-17, and TNF-α) and fibrosis-inducing molecules both in vivo and in vitro. These results suggest that metformin treatment has anti-inflammatory effects on lymphocytes via the inhibition of IL-17 and cytokines related to Th17 differentiation, such as IL-1ß, IL-6, and TNF-α. To investigate how metformin modulates the inflammatory process in skin fibroblasts, we measured mTOR-STAT3 signaling in skin fibroblasts and found that phosphorylated mTOR and phosphorylated STAT3 protein expression were decreased by metformin treatment. These results suggest that metformin has potential to treat scleroderma by inhibiting pro-inflammatory cytokines and anti-inflammatory activity mediated by mTOR-STAT3 signaling.

IL-17 Induced Stromal Cell-Derived Factor-1 and Profibrotic Factor in Keloid-Derived Skin Fibroblasts via the STAT3 Pathway.

The pathogenesis of keloids has not been elucidated, and the disease is thought to be caused by abnormal secretion of proinflammatory mediators and irregular responses to other inflammatory signals mediated by keloid fibroblasts (KFs). In this study, we investigated whether a local increase in interleukin IL-17 in keloid tissues stimulates the production of stromal cell-derived factor-1 (SDF-1) in KFs causing further recruitment of IL-17-producing T helper 17 (Th17) cells, which subsequently creates a positive feedback loop. Histological assessment was performed and the change in the expression of IL-17, IL-1ß, IL-6, and TNF-α which of fibrosis and inflammation associated markers was examined. In addition, fibroblasts were treated with IL-17 in the presence or absence of STAT3 inhibitor STA-21; SDF-1 levels and fibrosis genes were measured. Our results showed that fibrotic reaction and expression of proinflammatory cytokines including IL-17 were most prominent in the growing margin (perilesional area) of keloid tissue and Th17 cells significantly infiltrated the perilesional area. In addition, IL-17 upregulated the expression of SDF-1, collagen, and α-SMA in KFs. Finally, STA-21 decreased SDF-1α expression and the expression of fibrosis genes in KFs even after IL-17 stimulation. Our study demonstrated that a local increase in IL-17 in keloid tissues stimulates the production of SDF-1 in KFs causing further recruitment of IL-17-producing T helper 17 (Th17) cells, which subsequently creates a positive feedback loop. These findings suggest that STAT3 inhibition can be used to treat keloid scars by reversing the vicious cycle between Th17 cells and KFs.

Effects of Egg Shell Membrane Hydrolysates on UVB-radiation-induced Wrinkle Formation in SKH-1 Hairless Mice.

This study was conducted to examine the effect of egg shell membrane hydrolysates (ESMH) on wrinkle, UV, and moisture protection for cosmetic use. ESMH were fragmented as whole ESMH (before fractioning), Fraction I (> 10 kDa), Fraction II (3-10 kDa), and Fraction III (< 3 kDa). In order to test whether fractionated ESMH can be used for functional cosmetic materials, we examined not only the level of hyaluronic acid and collagen production, but also the MMP-1 activity using a HaCaT and CCD-986Sk cell line. Our study treated each sample of fractionated ESMH with different concentrations (0.01, 0.1, 1 mg/mL). In our in vivo research, we used hairless mice that had been exposed to UV-B to induce wrinkles for 7 wk, then applied Fraction I to the treatment group for 5 wk and then tested skin thickness, minimum erythema dose and moisture content. In addition, Fraction I was high in collagen and HA biosynthesis and it was better than TGF-ß in improving of the skin. When TNF-α caused MMP-1 activity in the CCD-986Sk cells, the whole ESMH and Fraction I proved to be effective in hindering the induction of collagenase depending on the concentration, and also showed outstanding effects in the suppression of skin aging. We found that the treatment group mice's UV-B radiation-induced skin damage was largely mitigated compared to that of the non-treatment group mice. Thus, we have concluded that EMSH helps to mitigate UV-B radiation-induced wrinkles, collagen, HA, MMP-1 activity and can be used for functional cosmetic materials.

Development of a selective agar plate for the detection of Campylobacter spp. in fresh produce.

This study was conducted to develop a selective medium for the detection of Campylobacter spp. in fresh produce. Campylobacter spp. (n=4), non-Campylobacter (showing positive results on Campylobacter selective agar) strains (n=49) isolated from fresh produce, indicator bacteria (n=13), and spoilage bacteria isolated from fresh produce (n=15) were plated on four Campylobacter selective media. Bolton agar and modified charcoal cefoperazone deoxycholate agar (mCCDA) exhibited higher sensitivity for Campylobacter spp. than did Preston agar and Hunt agar, although certain non-Campylobacter strains isolated from fresh produce by using a selective agar isolation method, were still able to grow on Bolton agar and mCCDA. To inhibit the growth of non-Campylobacter strains, Bolton agar and mCCDA were supplemented with 5 antibiotics (rifampicin, polymyxin B, sodium metabisulfite, sodium pyruvate, ferrous sulfate) and the growth of Campylobacter spp. (n=7) and non-Campylobacter strains (n=44) was evaluated. Although Bolton agar supplemented with rifampicin (BR agar) exhibited a higher selectivity for Campylobacter spp. than did mCCDA supplemented with antibiotics, certain non-Campylobacter strains were still able to grow on BR agar (18.8%). When BR agar with various concentrations of sulfamethoxazole-trimethoprim were tested with Campylobacter spp. (n=8) and non-Campylobacter (n=7), sulfamethoxazole-trimethoprim was inhibitory against 3 of 7 non-Campylobacter strains. Finally, we validated the use of BR agar containing 50mg/L sulfamethoxazole (BRS agar) or 0.5mg/L ciprofloxacin (BRCS agar) and other selective agars for the detection of Campylobacter spp. in chicken and fresh produce. All chicken samples were positive for Campylobacter spp. when tested on mCCDA, BR agar, and BRS agar. In fresh produce samples, BRS agar exhibited the highest selectivity for Campylobacter spp., demonstrating its suitability for the detection of Campylobacter spp. in fresh produce.

Factors Affecting Time to Bony Union of Femoral Subtrochanteric Fractures Treated with Intramedullary Devices.

PURPOSE: To evaluate the factors affecting the bone union time and the occurrence of nonunion after intramedullary nailing of subtrochanteric femoral fractures in adults. MATERIALS AND METHODS: We retrospectively reviewed data from 31 patients (22 men and 9 women) who had undergone femoral intramedullary nailing at least 1 year post-operatively and analyzed the bone union time, nonunion rates, and factors that affected the bone union time according to the fracture classification (AO and Fielding classifications), comminution of the medial cortex, reduction method, and additional cerclage wiring. RESULTS: The average union time was 26.4 weeks. There were no differences in the bone union time according to the fracture classification, reduction method, or additional cerclage wiring. Significant differences were found in the bone union time between the medial cortex comminution and non-comminution groups. A relatively strong positive correlation was detected between the degree of post-operative displacement and the bone union time. Nonunion occurred in three cases and there was no failure of implants. CONCLUSION: The bone union time was not affected by the reduction method nor additional cerclage wiring in intramedullary nailing of subtrochanteric femur fractures. Comminution of the medial cortex and the degree of the postoperative displacement of fractures contributed to the delayed time of union.

Aldose reductase inhibitor ameliorates renal vascular endothelial growth factor expression in streptozotocin-induced diabetic rats.

PURPOSE: The vascular endothelial growth factor (VEGF) expression of podocyte is one of the well-known major factors in development of diabetic nephropathy. In this study, we investigated the effects of aldose reductase inhibitor, fidarestat on diabetic nephropathy, and renal VEGF expression in a type 1 diabetic rat model. MATERIALS AND METHODS: Twenty four Sprague-Dawley male rats which were performed intraperitoneal injection of streptozotocin and normal six rats were divided into four groups including a normal control group, untreated diabetic control group, aldose reductase (AR) inhibitor (fidarestat, 16 mg kg(-1) day(-1)) treated diabetic group, and angiotensin receptor blocker (losartan, 20 mg kg(-1) day(-1)) treated diabetic group. We checked body weights and blood glucose levels monthly and measured urine albumin-creatinine ratio (ACR) at 8 and 32 weeks. We extracted the kidney to examine the renal morphology and VEGF expressions. RESULTS: The ACR decreased in fidarestat and losartan treated diabetic rat groups than in untreated diabetic group (24.79 +/- 11.12, 16.11 +/- 9.95, and 84.85 +/- 91.19, p < 0.05). The renal VEGF messenger RNA (mRNA) and protein expression were significantly decreased in the fidarestat and losartan treated diabetic rat groups than in the diabetic control group. CONCLUSION: We suggested that aldose reductase inhibitor may have preventive effect on diabetic nephropathy by reducing renal VEGF overexpression.

Dyspnea after supraclavicular brachial plexus block in a morbidly obese patient due to phrenic nerve block: A case report.

A 57-year-old woman with morbid obesity (BMI: 37.39) was scheduled for ligament reconstruction with tendon interposition of the carpometacarpal joint. A difficult supraclavicular brachial plexus block was performed using a 22-gauge regional block needle with a nerve stimulator and 40 ml of 1% mepivacaine. Approximately 10 minutes after the injection, she complained dyspnea, shortness of breath and right mid-thoracic pain. Her oxygen saturation decreased from 100% to 95%. Diagnostic workup revealed right diaphragmatic elevation caused by phrenic nerve block. General anesthesia was induced because of the unsuccessful brachial plexus block and dyspnea with chest pain. She recovered without any residual complications and was discharged on the third postoperative day. Phrenic nerve block is a common complication in supraclavicular brachial plexus block but it is usually not severe and reassurance is enough to control it. However, pre-operative physical conditions that may lead to decreased respiratory reserves, such as morbid obesity should be considered as a risk factors when conducting supraclavicular brachial plexus block.

A micellar prodrug of paclitaxel conjugated to cyclotriphosphazene.

A novel water soluble and biodegradable cyclotriphosphazene-paclitaxel conjugate was prepared by reacting 2'-succinyl paclitaxel with cyclotriphosphazenes bearing equimolar glycyl-L-lysine and methoxy poly(ethylene glycol) as side groups. The macromolecular conjugate was found to self-assemble in aqueous solution to form stable micelles with a mean hydrodynamic diameter of 24.7 nm and a low critical micelle concentration of 10 mg/L. The present conjugate exhibited lower than free paclitaxel but reasonably high in vitro cytotoxicity against selected human tumor cells due to their hydrolytic degradation in PBS solution.