SARS-CoV-2 rapidly evolves lineage-specific phenotypic differences when passaged repeatedly in immune-naïve mice.

The persistence of SARS-CoV-2 despite the development of vaccines and a degree of herd immunity is partly due to viral evolution reducing vaccine and treatment efficacy. Serial infections of wild-type (WT) SARS-CoV-2 in Balb/c mice yield mouse-adapted strains with greater infectivity and mortality. We investigate if passaging unmodified B.1.351 (Beta) and B.1.617.2 (Delta) 20 times in K18-ACE2 mice, expressing the human ACE2 receptor, in a BSL-3 laboratory without selective pressures, drives human health-relevant evolution and if evolution is lineage-dependent. Late-passage virus causes more severe disease, at organism and lung tissue scales, with late-passage Delta demonstrating antibody resistance and interferon suppression. This resistance co-occurs with a de novo spike S371F mutation, linked with both traits. S371F, an Omicron-characteristic mutation, is co-inherited at times with spike E1182G per Nanopore sequencing, existing in different within-sample viral variants at others. Both S371F and E1182G are linked to mammalian GOLGA7 and ZDHHC5 interactions, which mediate viral-cell entry and antiviral response. This study demonstrates SARS-CoV-2's tendency to evolve with phenotypic consequences, its evolution varying by lineage, and suggests non-dominant quasi-species contribution.

Stimulation of RAS-dependent ROS signaling extends longevity by modulating a developmental program of global gene expression.

We show that elevation of mitochondrial superoxide generation increases Caenorhabditis elegans life span by enhancing a RAS-dependent ROS (reactive oxygen species) signaling pathway (RDRS) that controls the expression of half of the genome as well as animal composition and physiology. RDRS stimulation mimics a program of change in gene expression that is normally observed at the end of postembryonic development. We further show that RDRS is regulated by negative feedback from the superoxide dismutase 1 (SOD-1)-dependent conversion of superoxide into cytoplasmic hydrogen peroxide, which, in turn, acts on a redox-sensitive cysteine (C118) of RAS. Preventing C118 oxidation by replacement with serine, or mimicking oxidation by replacement with aspartic acid, leads to opposite changes in the expression of the same large set of genes that is affected when RDRS is stimulated by mitochondrial superoxide. The identities of these genes suggest that stimulation of the pathway extends life span by boosting turnover and repair while moderating damage from metabolic activity.

ROS regulation of RAS and vulva development in Caenorhabditis elegans.

Reactive oxygen species (ROS) are signalling molecules whose study in intact organisms has been hampered by their potential toxicity. This has prevented a full understanding of their role in organismal processes such as development, aging and disease. In Caenorhabditis elegans, the development of the vulva is regulated by a signalling cascade that includes LET-60ras (homologue of mammalian Ras), MPK-1 (ERK1/2) and LIN-1 (an ETS transcription factor). We show that both mitochondrial and cytoplasmic ROS act on a gain-of-function (gf) mutant of the LET-60ras protein through a redox-sensitive cysteine (C118) previously identified in mammals. We show that the prooxidant paraquat as well as isp-1, nuo-6 and sod-2 mutants, which increase mitochondrial ROS, inhibit the activity of LET-60rasgf on vulval development. In contrast, the antioxidant NAC and loss of sod-1, both of which decrease cytoplasmic H202, enhance the activity of LET-60rasgf. CRISPR replacement of C118 with a non-oxidizable serine (C118S) stimulates LET-60rasgf activity, whereas replacement of C118 with aspartate (C118D), which mimics a strongly oxidised cysteine, inhibits LET-60rasgf. These data strongly suggest that C118 is oxidized by cytoplasmic H202 generated from dismutation of mitochondrial and/or cytoplasmic superoxide, and that this oxidation inhibits LET-60ras. This contrasts with results in cultured mammalian cells where it is mostly nitric oxide, which is not found in worms, that oxidizes C118 and activates Ras. Interestingly, PQ, NAC and the C118S mutation do not act on the phosphorylation of MPK-1, suggesting that oxidation of LET-60ras acts on an as yet uncharacterized MPK-1-independent pathway. We also show that elevated cytoplasmic superoxide promotes vulva formation independently of C118 of LET-60ras and downstream of LIN-1. Finally, we uncover a role for the NADPH oxidases (BLI-3 and DUOX-2) and their redox-sensitive activator CED-10rac in stimulating vulva development. Thus, there are at least three genetically separable pathways by which ROS regulates vulval development.

A single biochemical activity underlies the pleiotropy of the aging-related protein CLK-1.

The Caenorhabditis elegans clk-1 gene and the orthologous mouse gene Mclk1 encode a mitochondrial hydroxylase that is necessary for the biosynthesis of ubiquinone (UQ). Mutations in these genes produce broadly pleiotropic phenotypes in both species, including a lengthening of animal lifespan. A number of features of the C. elegans clk-1 mutants, including a maternal effect, particularly extensive pleiotropy, as well as unexplained differences between alleles have suggested that CLK-1/MCLK1 might have additional functions besides that in UQ biosynthesis. In addition, a recent study suggested that a cryptic nuclear localization signal could lead to nuclear localization in cultured mammalian cell lines. Here, by using immunohistochemical techniques in worms and purification techniques in mammalian cells, we failed to detect any nuclear enrichment of the MCLK1 or CLK-1 proteins and any biological activity of a C. elegans CLK-1 protein devoid of a mitochondrial localization sequence. In addition, and most importantly, by pharmacologically restoring UQ biosynthesis in clk-1 null mutants we show that loss of UQ biosynthesis is responsible for all phenotypes resulting from loss of CLK-1, including behavioral phenotypes, altered expression of mitochondrial quality control genes, and lifespan.

Antioxidants reveal an inverted U-shaped dose-response relationship between reactive oxygen species levels and the rate of aging in Caenorhabditis elegans.

Reactive oxygen species (ROS) are potentially toxic, but they are also signaling molecules that modulate aging. Recent observations that ROS can promote longevity have to be reconciled with the numerous claims about the benefits of antioxidants on lifespan. Here, three antioxidants [N-acetylcysteine (NAC), vitamin C, and resveratrol (RSV)] were tested on Caenorhabditis elegans mutants that alter drug uptake, mitochondrial function, and ROS metabolism. We observed that like pro-oxidants, antioxidants can both lengthen and shorten lifespan, dependent on concentration, genotypes, and conditions. The effects of antioxidants thus reveal an inverted U-shaped dose-response relationship between ROS levels and lifespan. In addition, we observed that RSV can act additively to both NAC and paraquat, to dramatically increase lifespan. This suggests that the effect of compounds that modulate ROS levels can be additive when their loci of action or mechanisms of action are sufficiently distinct.

Association of urinary incontinence with impaired functional status among older people living in a long-term care setting.

AIM: To examine the association between functional status and urinary incontinence. METHODS: A total of 27 participants with urinary incontinence and 50 participants without urinary incontinence were analyzed at a long-term care setting in Pingtung County, Taiwan, in 2011. The recruitment criteria were age older than 65 years, ability to communicate with the researcher, agreement to participate in the present study and potential ability to complete at least one measurement of functional status. Urinary incontinence was defined as urine leakage at least once a week during the past 4 weeks, whereas functional status was assessed by the body composition (body mass index and waist circumference), upper body strength (grasp test), lower body strength (30-s and 5-times chair stand test), upper body flexibility (back scratch test), lower body flexibility (chair sit-and-reach test) and agility/dynamic balance (8-ft up-and-go test). RESULTS: In univariate analyses, performances on the tests of 5-time chair stand, 30-s chair stand, 8-ft up-and-go, chair sit-and-reach, and grasp were significantly different between the participants with and without urinary incontinence (all P < 0.05). However, after multiple logistical regression adjusting sex, age and chronic illnesses, just two tests, 8-ft up-and-go and chair sit-and-reach, were independent predictors of urinary incontinence. CONCLUSION: Poor performance on the tests of 8-ft up-and-go and chair sit-and-reach were the predominated risk factors of urinary incontinence. Further studies regarding how to improve the functional status, especially focusing on the function of the lower body, might be required in order to enhance continence care.

The impact of mitochondrial oxidative stress on bile acid-like molecules in C. elegans provides a new perspective on human metabolic diseases.

C. elegans is a model used to study cholesterol metabolism and the functions of its metabolites. Several studies have reported that, in worms, cholesterol is not a structural component of the membrane as it is in vertebrates. However, as in other animals, it is used for the synthesis of steroid hormones that regulate physiological processes such as dauer formation, molting and defecation. After cholesterol is taken up by the gut, mechanisms of transport of cholesterol between tissues in C. elegans involve lipoproteins, as in mammals. A recent study shows that both cholesterol uptake and lipoprotein metabolism in C. elegans are regulated by molecules whose activities, biosynthesis, and secretion strongly resemble those of mammalian bile acids, which are metabolites of cholesterol that act on metabolism in a variety of ways. Importantly, it was found that oxidative stress upsets the regulation of the synthesis of these molecules. Given the known function of mammalian bile acids as metabolic regulators of lipid and glucose homeostasis, future investigations of the biology of C. elegans bile acid-like molecules could provide information on the etiology of human metabolic disorders that are characterized by elevated oxidative stress.

Community-based cross-sectional study: the association of lipids with hepatitis C seropositivity and diabetes mellitus.

BACKGROUND AND AIMS: Hepatitis C virus (HCV) infection is reported to be associated with or to cause type 2 diabetes mellitus (T2DM). Our study aimed to elucidate the role of triglyceride (TG) and cholesterol (CHOL) levels in the association between anti-HCV seropositivity and T2DM in an HCV-endemic area. METHODS: We analyzed a computerized dataset of 56 338 residents from a community-based comprehensive screening program in Tainan County in southern Taiwan. Fasting glucose, anti-HCV status, hepatitis B surface antigen (HBsAg) status, platelet counts, TG levels, CHOL levels, age, gender, and body mass index were included in the analyses. Multivariate logistic analysis was used to identify factors independently associated with T2DM. RESULTS: Older age, being overweight, thrombocytopenia, hypertriglyceridemia, hypercholesterolemia, anti-HCV seropositivity, and HBsAg seronegativity were common factors independently associated with diabetes. Among all models of multiple logistic regression analysis used for identifying factors independently associated with T2DM, anti-HCV seropositivity was only identified in the models that included either hypertriglyceridemia or hypercholesterolemia. When subjects were divided into hyperlipidemia (CHOL, > 200 or TG, > 150 mg/dL; n = 33 393) or non-hyperlipidemia subgroups (CHOL, < 200 and TG, < 150 mg/dL; n = 22 945), anti-HCV seropositivity was identified as an independent factor only in the non-hyperlipidemia subgroup. The odds ratio was 1.35, with a 95% confidence interval of 1.17-1.55. CONCLUSIONS: This study demonstrates that the lipid level is associated with the relationship between T2DM and anti-HCV seropositivity in non-hyperlipidemic individuals. However, the relationship between HCV and T2DM did not exist when the lipid level was not included in the analysis.

Mitochondrial oxidative stress alters a pathway in Caenorhabditis elegans strongly resembling that of bile acid biosynthesis and secretion in vertebrates.

Mammalian bile acids (BAs) are oxidized metabolites of cholesterol whose amphiphilic properties serve in lipid and cholesterol uptake. BAs also act as hormone-like substances that regulate metabolism. The Caenorhabditis elegans clk-1 mutants sustain elevated mitochondrial oxidative stress and display a slow defecation phenotype that is sensitive to the level of dietary cholesterol. We found that: 1) The defecation phenotype of clk-1 mutants is suppressed by mutations in tat-2 identified in a previous unbiased screen for suppressors of clk-1. TAT-2 is homologous to ATP8B1, a flippase required for normal BA secretion in mammals. 2) The phenotype is suppressed by cholestyramine, a resin that binds BAs. 3) The phenotype is suppressed by the knock-down of C. elegans homologues of BA-biosynthetic enzymes. 4) The phenotype is enhanced by treatment with BAs. 5) Lipid extracts from C. elegans contain an activity that mimics the effect of BAs on clk-1, and the activity is more abundant in clk-1 extracts. 6) clk-1 and clk-1;tat-2 double mutants show altered cholesterol content. 7) The clk-1 phenotype is enhanced by high dietary cholesterol and this requires TAT-2. 8) Suppression of clk-1 by tat-2 is rescued by BAs, and this requires dietary cholesterol. 9) The clk-1 phenotype, including the level of activity in lipid extracts, is suppressed by antioxidants and enhanced by depletion of mitochondrial superoxide dismutases. These observations suggest that C. elegans synthesizes and secretes molecules with properties and functions resembling those of BAs. These molecules act in cholesterol uptake, and their level of synthesis is up-regulated by mitochondrial oxidative stress. Future investigations should reveal whether these molecules are in fact BAs, which would suggest the unexplored possibility that the elevated oxidative stress that characterizes the metabolic syndrome might participate in disease processes by affecting the regulation of metabolism by BAs.

Lipid transport and signaling in Caenorhabditis elegans.

The strengths of the Caenorhabditis elegans model have been recently applied to the study of the pathways of lipid storage, transport, and signaling. As the lipid storage field has recently been reviewed, in this minireview we (1) discuss some recent studies revealing important physiological roles for lipases in mobilizing lipid reserves, (2) describe various pathways of lipid transport, with a particular focus on the roles of lipoproteins, (3) debate the utility of using C. elegans as a model for human dyslipidemias that impinge on atherosclerosis, and (4) describe several systems where lipids affect signaling, highlighting the particular properties of lipids as information-carrying molecules. We conclude that the study of lipid biology in C. elegans exemplifies the advantages afforded by a whole-animal model system where interactions between tissues and organs, and functions such as nutrient absorption, distribution, and storage, as well as reproduction can all be studied simultaneously.

Ultrasonographic evaluation of fetal facial anatomy (I): ultrasonographic features of normal fetal face in vitro study.

BACKGROUND: Because of lacking skills in scanning the normal fetal facial structures and their corresponding ultrasonic features, misdiagnoses frequently occur. Therefore, we studied the appearance features and improved displaying skills of fetal facial anatomy in order to provide basis for prenatal diagnosis. METHODS: Twenty fetuses with normal facial anatomy from induced labor because of other malformations except facial anomalies were immersed in a water bath and then scanned ultrasonographically on coronal, sagittal and transverse planes to define the ultrasonic image features of normal anatomy. The coronal and sagittal planes obtained from the submandibular triangle were used for displaying the soft and hard palate in particular. RESULTS: Facial anatomic structures of the fetus can be clearly displayed through the three routine orthogonal planes. However, the soft and hard palate can be displayed on the planes obtained from the submandibular triangle only. CONCLUSIONS: The superficial soft tissues and deep bony structures of the fetal face can be recognized and evaluated by routine ultrasonographic images, which is a reliable prenatal diagnostic technique to evaluate the fetal facial anatomy. The soft and hard palate can be well demonstrated by the submandibular triangle approach.

[Prenatal ultrasonographic evaluation of fetal limbs anatomy and fetal limbs malformations using a systematic continuous sequence approach].

OBJECTIVE: To review the value of ultrasonographic evaluation on fetal limbs anatomy and malformations in prenatal diagnosis using a systematic continuous sequence approach (SCSA). METHODS: Successive 4,932 prenatal ultrasonographic evaluation during gestation aging 14 - 40 weeks from August 2000 to September 2002 entered the present review. SCSA was applied to scan each limb of the fetus respectively. RESULTS: The anatomic structures of the four limbs of the fetus were clearly displayed and correctly recognized on ultrasonic images using the SCSA in 4 750 cases (96.3%). Ninety eight limb malformations of 34 fetuses were correctly diagnosed (87.2%). Whereas 16 malformations of 5 fetuses were missed to recognize (12.8%). The diagnoses were confirmed after subsequent labor or induced labor. The sensitivity, specificity, accuracy, positive and negative predictive values were 87.2%, 99.8%, 99.2%, 81.0% and 99.9%, respectively. CONCLUSION: The majority of fetal limb structures and malformations can be clearly demonstrated on prenatal ultrasonic imaging using SCSA. SCSA for prenatal ultrasonographic evaluation of the fetal limbs is a reliable and accurate diagnostic modality so far as the skills become more sophisticated.