Design of a synthetic enzyme cascade for the in vitro fixation of formaldehyde to acetoin

Formaldehyde (FALD) has gained prominence as an essential C1 building block in the synthesis of valuable chemicals. However, there are still challenges in converting FALD into commodities. Recently, cell-free biocatalysis has emerged as a popular approach for producing such commodities. Acetoin, also known as 3-hydroxy-2-butanone, has been widely used in food, cosmetic, agricultural and the chemical industry. It is valuable to develop a process to produce acetoin from FALD. In this study, a cell-free multi-enzyme catalytic system for the production of acetoin using FALD as the substrate was designed and constructed. It included three scales: FALD utilization pathway, glycolysis pathway and acetoin synthesis pathway. After the optimization of the reaction system, 20.17 mM acetoin was produced from 122 mM FALD, with a yield of 0.165 mol/mol, reaching 99.0% of the theoretical yield. The pathway provides a new approach for high-yield acetoin production from FALD, which consolidates the foundation for the production of high value-added chemicals using cheap one-carbon compounds.

Ovarian PERK/NRF2/CX43/StAR/progesterone pathway activation mediates female reproductive dysfunction induced by cold exposure

Ambient air temperature is a key factor affecting human health. Female reproductive disorders are representative health risk events under low temperature. However, the mechanism involving in cold-induced female reproductive disorders remains largely unknown. Female mice were intermittently exposed to cold conditions (4 °C) to address the health risk of low temperature on female reproductive system. Primary granulosa cells (GCs) were prepared and cultured under low temperature (35 °C) or exposed to β3-adrenoreceptor agonist, isoproterenol, to mimic the condition of cold exposure. Western-blot, RT-PCR, co-IP, ELISA, pharmacological inhibition or siRNA-mediated knockdown of target gene were performed to investigate the possible role of hormones, gap conjunction proteins, and ER stress sensor protein in regulating female reproductive disorders under cold exposure. Cold exposure induced estrous cycle disorder and follicular dysplasia in female mice, accompanying with abnormal upregulation of progesterone and its synthetic rate-limiting enzyme, StAR, in the ovarian granulosa cells. Under the same conditions, an increase in connexin 43 (CX43) expressions in the GCs was also observed, which contributed to elevated progesterone levels in the ovary. Moreover, ER stress sensor protein, PERK, was activated in the ovarian GCs after cold exposure, leading to the upregulation of downstream NRF2-dependent CX43 transcription and aberrant increase in progesterone synthesis. Most importantly, blocking PERK expression in vivo significantly inhibited NRF2/CX43/StAR/progesterone pathway activation in the ovary and efficiently rescued the prolongation of estrous cycle and the increase in follicular atresia of the female mice induced by cold stress. We have elucidated the mechanism of ovarian PERK/NRF2/CX43/StAR/progesterone pathway activation in mediating female reproductive disorder under cold exposure. Targeting PERK might be helpful for maintaining female reproductive health under cold conditions.

Sleep deprivation reduced LPS-induced IgG2b production by up-regulating BMAL1 and CLOCK expression

Sleep deprivation (SD) weakens the immune system and leads to increased susceptibility to infectious or inflammatory diseases. However, it is still unclear how SD affects humoral immunity. In the present study, sleep disturbance was conducted using an sleep deprivation instrument, and the bacterial endotoxin lipopolysaccharide (LPS) was used to activate the immune response. It was found that SD-pretreatment reduced LPS-induced IgG2b+ B cells and IgG2b isotype antibody production in lymphocytes of spleen. And, SD-pretreatment decreased the proportion of CD4+T cells, production of CD4+T cells derived TGF-β1 and its contribution in helping IgG2b production. Additionally, BMAL1 and CLOCK were selectively up-regulated in lymphocytes after SD. Importantly, BMAL1 and CLOCK deficiency contributed to TGF-β1 expression and production of IgG2b+ B cells. Thus, our results provide a novel insight to explain the involvement of BMAL1 and CLOCK under SD stress condition, and their roles in inhibiting TGF-β1 expression and contributing to reduction of LPS induced IgG2b production.

Riboswitches, from cognition to transformation

Riboswitches are functional RNA elements that regulate gene expression by directly detecting metabolites. Twenty years have passed since it was first discovered, researches on riboswitches are becoming increasingly standardized and refined, which could significantly promote people's cognition of RNA function as well. Here, we focus on some representative orphan riboswitches, enumerate the structural and functional transformation and artificial design of riboswitches including the coupling with ribozymes, hoping to attain a comprehensive understanding of riboswitch research.

Efficient production of acetoin from lactate by engineered Escherichia coli whole-cell biocatalyst

Acetoin, an important and high-value added bio-based platform chemical, has been widely applied in fields of foods, cosmetics, chemical synthesis, and agriculture. Lactate is a significant intermediate short-chain carboxylate in the anaerobic breakdown of carbohydrates that comprise ~ 18% and ~ 70% in municipal wastewaters and some food processing wastewaters, respectively. In this work, a series of engineered Escherichia coli strains were constructed for efficient production of acetoin from cheaper and abundant lactate through heterogenous co-expression of fusion protein (α-acetolactate synthetase and α-acetolactate decarboxylase), lactate dehydrogenase and NADH oxidase, and blocking acetate synthesis pathways. After optimization of whole-cell bioconversion conditions, the engineered strain BL-11 produced 251.97 mM (22.20 g/L) acetoin with a yield of 0.434 mol/mol in shake flasks. Moreover, a titer of 648.97mM (57.18 g/L) acetoin was obtained in 30 h with a yield of 0.484 mol/mol lactic acid in a 1-L bioreactor. To the best of our knowledge, this is the first report on the production of acetoin from renewable lactate through whole-cell bioconversion with both high titer and yield, which demonstrates the economy and efficiency of acetoin production from lactate. Key Points • The lactate dehydrogenases from different organisms were expressed, purified, and assayed. • It is the first time that acetoin was produced from lactate by whole-cell biocatalysis. • The highest titer of 57.18 g/L acetoin was obtained with high theoretical yield in a 1-L bioreactor.

Acute hypoxia induced dysregulation of clock-controlled ovary functions

High altitudes or exposure to hypoxia leads to female reproductive disorders. Circadian clocks are intrinsic time-tracking systems that enable organisms to adapt to the Earth's 24-h light/dark cycle, which can be entrained by other environmental stimuli to regulate physiological and pathological responses. In this study, we focused on whether ovarian circadian clock proteins were involved in regulating female reproductive dysfunction under hypoxic conditions. Hypobaric hypoxia was found to induce a significantly prolonged estrous cycle in female mice, accompanied by follicular atresia, pituitary/ovarian hormone synthesis disorder, and decreased LHCGR expression in the ovaries. Under the same conditions, the levels of the ovarian circadian clock proteins, CLOCK and BMAL1, were suppressed, whereas E4BP4 levels were upregulated. Results from granulosa cells (GCs) further demonstrated that CLOCK: BMAL1 and E4BP4 function as transcriptional activators and repressors of LHCGR in ovarian GCs, respectively, whose responses were mediated by HIF1ɑ-dependent (E4BP4 upregulation) and ɑ-independent (CLOCK and BMAL1 downregulation) manners. The LHCGR agonist was shown to efficiently recover the impairment of ovulation-related gene (EREG and PGR) expression in GCs induced by hypoxia. We conclude that hypoxia exposure causes dysregulation of ovarian circadian clock protein (CLOCK, BMAL1, and E4BP4) expression, which mediates female reproductive dysfunction by impairing LHCGR-dependent signaling events. Adjusting the timing system or recovering the LHCGR level in the ovaries may be helpful in overcoming female reproductive disorders occurring in the highlands.

Lactation time influences the composition of Bifidobacterium and Lactobacillus at species level in human breast milk

Human breast milk is a source of microorganisms for infants that play an important role in building infant gut health and immunity. The bacterial composition in human breast milk is influenced by lactation time. This study aimed to investigate the influence of lactation time on bacteria in breast milk at the genus level and the species levels of Bifidobacterium and Lactobacillus on days 2-4, 8, 14, and 30. Eighteen individuals were recruited and 60 milk samples were collected. The 16S rRNA gene, and the bifidobacterial groEL and lactobacilli groEL genes were used for amplicon sequencing. The results revealed that the alpha diversities of colostrum and transition 1 (day 8) milk were lower than that of transition 2 (day 14) and mature milk. PCoA analysis showed that bacterial composition in colostrum and transition 1 milk differed from transition 2 and mature milk. A lower relative abundance of Blautia was found in colostrum and transition 1 milk compared with mature milk and lower abundances of Ruminococcus, Dorea, and Escherichia-Shigella were found in transition 1 compared with mature milk. Bifidobacterium ruminantium, Limosilactobacillus mucosae, and Ligilactobacillus ruminis were the predominant species across all four lactation stages, while Bifidobacterium bifidum was lower in transition 1, and Bifidobacterium pseudocatenulatum and Bifidobacterium pseudolongum were higher in transition 1 milk. This study indicated that the bacterial composition in colostrum was more similar to that of transition 1 milk, whereas the bacterial community in transition 2 milk was similar to that of mature milk which suggests that bacterial composition in human breast milk shows stage-specific signatures even within a short period at both genus level and Bifidobacterium and Lactobacillus species levels, providing insights into probiotic supplementation for the nursing mother.

Portable fluid circuit device containing printed silicone microvessels as a training aid for arterial microanastomosis

Anastomosis of the microvessels requires high-level skills and extensive basic training. This study was performed to introduce and evaluate an inexpensive laboratory device as a training aid. Micro-tubes of 0.8 mm inner diameter and 0.5/0.8 mm wall thickness mimicking human vein/artery were printed from a silicon-containing hydrogel using three-dimensional printing technology. The hydrogel components are optimized to render the printed tubes biomechanical features resembling the blood vessels of a living organism. These artificial vessels were connected to a pump for fluid flow, simulating the blood circulation. Forty medical interns were assigned to two equal groups. The 20 interns in group A practiced anastomosis using the training aid for a total of 10 hours over 5 days. The 20 interns in group B practiced anastomosis using the traditional gum pieces and silicone tubes. Then, all interns performed anastomosis on rat carotid arteries, and their performance was scored by a team of five experienced maxillofacial surgeons. The average success score and time required for anastomosis were compared between the two groups. The mean success score of group A was significantly higher than that of group B (0.83 ± 0.12 vs 0.64 ± 0.10, P < 0.001). The mean anastomosis time of group A was significantly shorter than that of group B (10.2 ± 1.1 vs 17.2 ± 1.4 minutes, P < 0.001). This training device for vessel microanastomosis is an inexpensive, practical, and effective tool for use in laboratories and also reduces the use of animals.

Circadian oscillation expression of ornithine carbamoyltransferase and its significance in sleep disturbance

Ornithine transcarbamylases (OTC), a key enzyme in urea cycle, is an important marker for some liver injury or diseases. However, whether OTC could be a sensitive indicator for liver dysfunction under sleep disturbance condition remains unknown. The present study aimed to explore the circadian oscillation expression of OTC and its significance in disturbed sleep condition. Sleep disturbance was conducted by a sleep deprivation (SD) instrument. Our results found that SD for 72h induced abnormal increasing of OTC levels in serum and liver of rats. And, serum OTC concentration and liver OTC expression could return to normal levels after recovery sleep following SD. Moreover, hepatic OTC expression showed circadian oscillation in day and night, characterized with occurrence of a peak between ZT 22 and ZT 2, and a nadir between ZT 14 and ZT 18. Further analysis suggested the existence of ROR response element (RORE) for potential RORɑ binding sites in OTC promoter region, and elevated RORɑ expression in rat livers under sleep disturbance condition. Additionally, oscillation expression of OTC induced by serum shock in HepG2 cells was characterized with a peak occurred between ZT 12 and ZT 16, and RORɑ knockdown at ZT 16 significantly lowered OTC expression. The results together indicate that OTC is closely correlated with circadian clock, and could be a sensitive indicator for sleep disturbance stress.

[Research progress in the role and mechanism of polysaccharides in regulating glucose and lipid metabolism]

Polysaccharides are a group of compounds composed of multiple monosaccharides of the same or different structures combined by glycosidic bonds, and are widely found in animals and plants and in the cell walls of microorganisms. Polysaccharides possess the advantages of high safety and low toxicity. Recent studies revealed that polysaccharides have a wide range of biological activities including immunoregulation, anti-tumor, antiviral, antioxidant activities, and blood glucose-and lipid- lowering effects. The effects of polysaccharides in improving insulin sensitivity and regulating glucose and lipid metabolism have drawn much attention from researchers. Many polysaccharides can reduce blood glucose and blood lipid by repairing pancreatic islet cells, improving insulin resistance, regulating intestinal flora, enhancing antioxidant capacity, and regulating the activities of key enzymes in glucose and lipid metabolism. This reviews examines the role and mechanism of polysaccharides in regulating glucose and lipid metabolism. The mechanisms of polysaccharide in regulating glucose metabolism include repairing islet cells and increasing insulin content, increasing insulin sensitivity and improving insulin resistance, regulating the activity of key enzymes in glucose metabolism, increasing synthesis of liver glycogen, and regulating intestinal flora. Polysaccharides can also regulate glucose metabolism by improving immune regulation and antagonizing glucagon. Polysaccharide also regulate lipid metabolism by regulating lipid absorption, expression of the related genes such as PPAR-α, enzyme activities in lipid metabolism, improving antioxidant capacity, and modulating intestinal flora and signaling pathways.

Sleep disturbance induces depressive behaviors and neuroinflammation by altering the circadian oscillations of clock genes in rats

Sleep loss leads to a spectrum of mood disorders such as anxiety disorders, bipolar disorder and depression in many individuals. However, the underlying mechanisms are largely unknown. In this study, sleep-disturbed animals were tested for anxiety and depressive behaviors. We then studied the effects of SD on hypothalamic-pituitary-adrenal (HPA) axis function by measuring serum and CSF levels of corticosterone (CORT), and at the end of the experiment, brains were collected to measure the circadian oscillations of clock genes expression in the hypothalamus, glial cell activation and inflammatory cytokine alterations. Our results indicated that SD for 3 days resulted in anxiety- and depressive-like behaviors. SD exaggerated cortisol response to HPA axis, significantly altered the circadian oscillations of clock genes, decreased the expression of tight junction protein ZO-1 and Claudin 5 and increased the number of GFAP-positive cells and Iba-1-positive cells and caused subsequent elevation of pro-inflammatory cytokines IL-6, IL-1β and TNFα. These findings demonstrated that SD for 3 days induced anxiety- and depression-like behaviors in rats in company with altering the circadian oscillations of clock genes and inducing neuroinflammation, indicating the underlying mechanism of sleep loss induced neuronal dysfunction.

Sarcopenia as a Risk Factor for Future Hip Fracture: A Meta-Analysis of Prospective Cohort Studies

OBJECTIVE

Our study aims to determine whether sarcopenia is a predictive factor of future hip fractures.

DESIGN

Systematic review and meta-analysis. Set: We searched for potentially suitable articles in PubMed, Cochrane library, Medline and EMBASE from inception to March 2020. The quality of the research was assessed by the Newcastle-Ottawa Scale (NOS). Finally, a meta-analysis was conducted with the Stata software.

PARTICIPANTS

Older community-dwelling residents.

MEASUREMENTS

Hip fracture due to sarcopenia.

RESULTS

We retrieved 2129 studies through our search strategy, and five studies with 23,359 individuals were analyzed in our pooled analyses. Sarcopenia increases the risk of future hip fractures with a pooled hazard ratio (HR) of 1.42 (95% CI: 1.18-1.71, P <0.001, I2 = 37.7%). In addition, in subgroup analyses based on different definitions of sarcopenia, sarcopenia was associated with the risk of future hip fractures with the Asian Working Group for Sarcopenia (AWGS) criteria with a pooled HR of 2.13(95% CI: 1.33-3.43). When subgroup analyses were conducted by sex, sarcopenia was associated with the risk for future hip fractures in females with pooled HRs of 1.69 (95% CI: 1.18-2.43). Sarcopenia was associated with the risk of future hip fractures in the group with a follow-up period of more than 5 years, with a pooled HR of 1.32 (95% CI: 1.08-1.61), and in the group with a follow-up period of less than 5 years, with a pooled HR of 2.13 (95% CI: 1.33-3.43).

CONCLUSIONS

Sarcopenia could significantly increase the risk of future hip fracture in old people; thus, it is necessary to prevent hip fractures in individuals with sarcopenia.

Sleep Disturbance Induces Increased Cholesterol Level by NR1D1 Mediated CYP7A1 Inhibition

Disturbed sleep is closely associated with an increased risk of metabolic diseases. However, the underlying mechanisms of circadian clock genes linking sleep and lipid profile abnormalities have not been fully elucidated. This study aimed to explore the important role of the circadian clock in regulating impaired cholesterol metabolism at an early stage of sleep deprivation (SD). Sleep disturbance was conducted using an SD instrument. Our results showed that SD increased the serum cholesterol levels. Concentrations of serum leptin and resistin were much lower after SD, but other metabolic hormone concentrations (adiponectin, glucagon, insulin, thyroxine, norepinephrine, and epinephrine) were unchanged before and after SD. Warning signs of cardiovascular diseases [decreased high density lipoprotein (HDL)-cholesterol and increased corticosterone and 8-hydroxyguanosine levels] and hepatic cholestasis (elevated total bile acids and bilirubin levels) were observed after SD. Cholesterol accumulation was also observed in the liver after SD. The expression levels of HMGCR, the critical enzyme for cholesterol synthesis, remained unchanged in the liver. However, the expression levels of liver CYP7A1, the enzyme responsible for the conversion of cholesterol into bile acids, significantly reduced after SD. Furthermore, expression of NR1D1, a circadian oscillator and transcriptional regulator of CYP7A1, strikingly decreased after SD. Moreover, NR1D1 deficiency decreased liver CYP7A1 levels, and SD could exacerbate the reduction of CYP7A1 expression in NR1D1^-/- mouse livers. Additionally, NR1D1 deficiency could further increase serum cholesterol levels under SD. These results suggest that sleep disturbance can induce increased serum cholesterol levels and liver cholesterol accumulation by NR1D1 mediated CYP7A1 inhibition.

FULLEROL alleviates myocardial ischemia-reperfusion injury by reducing inflammation and oxidative stress in cardiomyocytes via activating the Nrf2/HO-1 signaling pathway

OBJECTIVE

Myocardial ischemia-reperfusion injury (MIRI) is myocardial tissue injury caused by blood supply returning to myocardial tissue after ischemia or hypoxia. The purpose of this study was to investigate the protective effect of FULLEROL on myocardial tissue in MIRI rats and its mechanism.

MATERIALS AND METHODS

We use rats and ligate their left anterior descending coronary artery to make a MIRI model, and we also subcutaneously injected some MIRI rats with FULLEROL daily for two weeks before modeling. We determined the effects of model building and the therapeutic effect of FULLEROL on MIRI by detecting the changes of myocardial tissue morphology, myocardial injury markers and cardiac function in rats. In addition, we detected the expression changes of inflammatory factors and antioxidative molecules in rat myocardial tissue and serum to determine the effect of FULLEROL on inflammation and oxidative stress in myocardial tissue. Finally, we detected the activity of the Nrf2/HO-1 signaling pathway in rat cardiomyocytes to determine the mechanism of action of FULLEROL.

RESULTS

The structure of myocardial tissue in MIRI rats was remarkably damaged, and the range of myocardial infarction was increased. In addition, the concentrations of creatine kinase and lactate dehydrogenase were increased, and the heart function was reduced, while FULLEROL could reverse these conditions. In addition, FULLEROL was found to reduce the concentration of the inflammatory factors in rat myocardial tissue and serum, and to increase the expression of antioxidative molecules in myocardial tissue. The Nrf2/HO-1 signaling pathway was found to be related to MIRI and FULLEROL could increase the activity of the Nrf2/HO-1 signaling pathway in cardiomyocytes.

CONCLUSIONS

FULLEROL can alleviate MIRI by promoting the activity of the Nrf2/HO-1 signaling pathway to reduce the expression of inflammatory factors in rats and increase the antioxidative capacity of cardiomyocytes.

Protective effects of melatonin on mitochondrial biogenesis and mitochondrial structure and function in the HEK293-APPswe cell model of Alzheimer's disease

OBJECTIVE

The effects and mechanisms of melatonin on Alzheimer's disease (AD) are still not researched thoroughly. 20E2 cells (HEK293-APPswe cells) are a cellular model of AD. The modulation effects of melatonin on the structure and function of mitochondria in 20E2 cells need to be studied.

MATERIALS AND METHODS

The Alzheimer's disease (AD) cell model was assessed for cell viability, expression levels of mitochondrial biogenesis factors (peroxisome proliferator-activated receptor gamma coactivator 1-alpha [PGC-1α], nuclear respiratory factor 1 [NRF1], nuclear respiratory factor 2 [NRF2], mitochondrial transcription factor A [TFAM]), mitochondrial membrane potential, Na+-K+-adenosine triphosphatase (ATPase) and cytochrome C oxidase activity, adenosine triphosphate (ATP) level, mitochondrial DNA/nuclear DNA (mtDNA/nDNA) ratio, and mitochondrial structure with and without melatonin.

RESULTS

Melatonin improved 20E2 cell viability, expression of mitochondrial biogenesis factors (PGC-1α, NRF1, NRF2, TFAM), mitochondrial membrane potential, Na+-K+-ATPase, and cytochrome C oxidase activity, ATP level, mtDNA/nDNA ratio, mitochondrial structure, and decreased amyloidogenic amyloid precursor protein processing.

CONCLUSIONS

Mitochondrial biogenesis disorder is associated with the pathogenesis of AD through PGC-1α-NRF-TFAM pathway, and melatonin improves the mitochondrial structure and function by enhancing mitochondrial biogenesis and decreasing amyloidogenic APP processing in Alzheimer's disease.

Characterization of a P18 protein in the S1 segment of the novel duck reovirus genome

Novel duck reovirus (NDRV), the prototype strain of avian orthoreoviruses, continues to circulate among ducks. Analysis of its genome suggested that a putative second open reading frame in the S1 segment encodes a 162-amino acid nonstructural protein with size of 18 kDa, provisionally designated P18. This protein is different from the 17 kDa nonstructural protein encoded in the same open reading frame in other avian orthoreoviruses, which is designated P17 and consists of 146 amino acids. There is no corresponding protein in Muscovy duck reovirus. Antibodies raised to the purified recombinant protein reacted with viral P18 both in vitro and in vivo. In cells, P18 was located predominantly in the nucleus at 6-12 h post-infection, with negligible levels in the cytoplasm. However, the protein accumulated both in the nucleus and cytoplasm at 24 to 36 h post-infection. Immunohistochemistry indicated that P18 strongly accumulates in spleen tissues of infected ducklings. Collectively, the data provide the direct experimental evidence that P18 is expressed by novel duck reovirus both in vivo and in vitro. Keywords: duck reovirus; expression; characterization; novel P18 protein.

Solution-Processed Submicron Free-Standing, Conformal, Transparent, Breathable Epidermal Electrodes

Long-term, real-time, and comfortable epidermal electronics are of great practical importance for healthcare monitoring and human-machine interaction. However, traditional physiological signal monitoring confined by the specific clinical sites and unreliability of the epidermal electrodes leads to great restrictions on its application. Herein, we constructed a solution-processed submicron (down to 230 nm), free-standing, breathable sandwich-structured hybrid electrode composed of a silver nanowire network with a conductive polymer film, which is conformal, water-permeable, and noninvasive to the skin while achieving good signal acquisition ability. The free-standing hybrid electrode is prepared via an in situ capillary force lift-off process and can be transferred onto complex surfaces. The whole process is a complete solution process that facilitates large-area preparation and application. The light-weight hybrid electrodes exhibit high optical transmittance, high electrical conductivity, and high gas/ion permeability. When the hybrid electrodes are attached onto the skin, the imperceptible films show high conformality with low electrical impedance, thus exhibiting significantly improved electrocardiology and electromyogram signal monitoring performance compared to that of the commercial gel electrodes.

Selective degradation of IKKα by autophagy is essential for arsenite-induced cancer cell apoptosis

Two catalytic subunits of the IKK complex, IKKα and IKKβ, trigger NF-κB activation as well as NF-κB-independent signaling events under both physiological and pathological conditions. Here we identified the NF-κB-unrelated cytoprotective function of IKKα in promoting autophagy by triggering p53 transactivation and upregulation of its downstream autophagic mediator, DRAM1, in the arsenite-treated hepatoma cells, which responses depended on IKKα kinase activity. Furthermore, IKKα triggered p53/DRAM1-dependent autophagy by inducing CHK1 activation and CHK1/p53 interaction. Interestingly, after provoking autophagy, IKKα could be specifically recognized by the autophagic machinery via directly binding with LC3B, resulting in selective degradation of IKKα by autophagy. Unexpectedly, the selectivity of autophagic sequestration towards IKKα was mediated by novel mechanism independent of the classical LC3-interacting regions (LIRs) within IKKα, while C-terminal arm of LIR was involved in mediating IKKα/LC3B interaction. Taken together, we conclude that IKKα attenuates arsenite-induced apoptosis by inducing p53-dependent autophagy, and then selective feedback degradation of IKKα by autophagy contributes to the cytotoxic response induced by arsenite.

Probiotic Supplements: Hope or Hype?

Probiotic bacteria have been associated with various health benefits and included in overwhelming number of foods. Today, probiotic supplements are consumed with increasing regularity and record a rapidly growing economic value. With billions of heterogeneous populations of probiotics per serving, probiotic supplements contain the largest quantity of probiotics across all functional foods. They often carry antibiotic-resistant determinants that can be transferred to and accumulate in resident bacteria of the gastrointestinal tract and risk their acquisitions by opportunistic pathogens. While the health benefits of probiotics have been widely publicized, this health risk, however, is underrepresented in both scientific studies and public awareness. On the other hand, the human gut presents conditions that are unfavorable for bacteria, including probiotics. It remains uncertain if probiotics from supplements can tolerate acids and bile salts that may undermine their effectiveness in conferring health benefits. Here, we put into perspective the perceived health benefits and the long-term safety of consuming probiotic supplements, specifically bringing intolerance to acids and bile salts, and the long-standing issue of antibiotic-resistant gene transfer into sharp focus. We report that probiotics from supplements examined in this study have poor tolerance to acids and bile salts while also displaying resistance to multiple antibiotics. They could also adapt and gain resistance to streptomycin in vitro. In an environment where consuming supplements is considered a norm, our results and that of others will put in perspective the persisting concerns surrounding probiotic supplements so that the current hype does not overpower the hope.