Discovery and functional interrogation of SARS-CoV-2 RNA-host protein interactions

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Decreased dengue cases attributable to the effect of COVID-19 in Guangzhou in 2020

The dengue fever epidemic in Guangzhou may have been affected by the Coronavirus Disease 2019 (COVID-19) pandemic. The number of dengue cases dropped drastically in 2020, and there have been only 2 local cases, suggesting that dengue has not become endemic in Guangzhou.

Guangzhou is located on the southeast coast of China and is the country’s third largest city. Since 1978, outbreaks of dengue fever have occurred intermittently in this city. In the past decade, the number of reported dengue cases reached more than 1,000 in 2013, 2014, 2018, and 2019, with 37,385 cases reported in 2014 alone. Therefore, dengue fever is a major public health concern in Guangzhou, and there is a continuing argument that it is endemic in Guangzhou [1–3].The numbers of dengue cases from 2017 to 2020 are shown in Table 1. In 2020, the total and local case numbers dropped dramatically compared to the previous years. With a high proportion of imported cases (n = 32, 94.12%), the proportion of local cases (n = 2, 5.88%) was considerably low in 2020. All the prevention and control strategies for dengue, including issuing public education messages, preventing further mosquito bites in patients, cleaning vector breeding sites, and using pesticides, were similar during these years. Additionally, dengue, as a mosquito-borne viral infectious disease, is closely related to mosquito density. The mosquito ovitrap index (MOI), which is the proportion of positive mosquito ovitraps, is usually used to indicate mosquito density. The MOI in 2017, 2018, and 2019 was 7.073 ± 1.016, 9.657 ± 1.307, and 8.464 ± 0.961, respectively. The average MOI was 8.398 ± 0.648 from 2017 to 2019 in Guangzhou. The MOI in 2020 was 7.135 ± 0.786, which remained at the median risk level. Therefore, the abnormal decline in dengue cases could not be attributed to the change in mosquito density in 2020.Table 1Numbers and percentages of dengue cases from 2017 to 2019.

Association between misalignment of circadian rhythm and obesity in Korean men: Sixth Korea National Health and Nutrition Examination Survey

ABSTRACT

Background: The disruption of circadian rhythm has been found to associate with obesity in vivo and in vitro. Sleep duration, eating habits, total feeding time, and nightshift work can also affect circadian rhythms. This study investigated the association between misalignment of circadian rhythm and obesity in Korean men, using a cross-sectional database.

Methods: This study used data from the Korean National Health and Nutrition Examination Survey (KNHANES), whose study population was 3,658 men aged 18 to 60 years. General and abdominal obesity was defined as a body mass index (BMI) ≥ 25 kg/m² and waist circumference ≥ 90 cm, respectively. Circadian rhythm factors were determined with a self-report questionnaire and included breakfast frequency, sleep duration, and work time. Frequency of breakfast was divided into regular breakfast (five to seven times a week) and irregular breakfast (less than five times a week). Sleep duration was divided into less than 7 hours, 7–9 hours, and over 9 hours. Working time was defined as day/evening, night shift, and other type. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for general and abdominal obesity were calculated using multivariable logistic regression according to the number of factors that disturb the circadian rhythm.

Results: Participants with 1 (aOR 1.34, 95% Cl 1.10–1.61) and ≥2 (aOR 1.62, 95% Cl 1.29–2.05) factors disturbing circadian rhythms were associated with elevated risk for general obesity. Similarly, those with 1 (aOR 1.33, 95% Cl 1.09–1.63) and ≥2 (aOR 1.70, 95% Cl 1.32–2.20) factors had elevated risk for abdominal obesity.

Conclusions: Factors disturbing the circadian rhythm were associated with general and abdominal obesity. Additional studies are needed, and associations with metabolic diseases should be investigated.     

Caspase cleavage releases a nuclear protein fragment that stimulates phospholipid scrambling at the plasma membrane

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Growth hormone signaling is necessary for lifespan extension by dietary methionine

Growth hormone significantly impacts lifespan in mammals. Mouse longevity is extended when growth hormone (GH) signaling is interrupted but markedly shortened with high‐plasma hormone levels. Methionine metabolism is enhanced in growth hormone deficiency, for example, in the Ames dwarf, but suppressed in GH transgenic mice. Methionine intake affects also lifespan, and thus, GH mutant mice and respective wild‐type littermates were fed 0.16%, 0.43%, or 1.3% methionine to evaluate the interaction between hormone status and methionine. All wild‐type and GH transgenic mice lived longer when fed 0.16% methionine but not when fed higher levels. In contrast, animals without growth hormone signaling due to hormone deficiency or resistance did not respond to altered levels of methionine in terms of lifespan, body weight, or food consumption. Taken together, our results suggest that the presence of growth hormone is necessary to sense dietary methionine changes, thus strongly linking growth and lifespan to amino acid availability.     

Green Tea Polyphenol Epigallocatechin Gallate Inhibits Adipogenesis and Induces Apoptosis in 3T3‐L1 Adipocytes

Objective: Green tea catechins have been shown to promote loss of body fat and to inhibit growth of many cancer cell types by inducing apoptosis. The objective of this study was to determine whether epigallocatechin gallate (EGCG), the primary green tea catechin, could act directly on adipocytes to inhibit adipogenesis and induce apoptosis. Research Methods and Procedures: Mouse 3T3‐L1 preadipocytes and mature adipocytes were used. To test the effect of EGCG on viability, cells were incubated for 3, 6, 12, or 24 hours with 0, 50, 100, or 200 μM EGCG. Viability was quantitated by MTS assay. To determine the effect of EGCG on apoptosis, adipocytes were incubated for 24 hours with 0 to 200 μM EGCG, then stained with annexin V and propidium iodide and analyzed by laser scanning cytometry. Both preadipocytes and adipocytes were also analyzed for apoptosis by terminal deoxynucleotidyl transferase dUTP nick‐end labeling assay. To determine the effect of EGCG on adipogenesis, maturing preadipocytes were incubated during the 6‐day induction period with 0 to 200 μM EGCG, then stained with Oil‐Red‐O and analyzed for lipid content. Results: EGCG had no effect on either viability or apoptosis of preconfluent preadipocytes. EGCG also did not affect viability of mature adipocytes; however, EGCG increased apoptosis in mature adipocytes, as demonstrated by both laser scanning cytometry and terminal deoxynucleotidyl transferase dUTP nick‐end labeling assays. Furthermore, EGCG dose‐dependently inhibited lipid accumulation in maturing preadipocytes. Discussion: These results demonstrate that EGCG can act directly to inhibit differentiation of preadipocytes and to induce apoptosis of mature adipocytes and, thus, could be an important adjunct in the treatment of obesity.     

Change in Vascular Adhesion Protein‐1 and Metabolic Phenotypes after Vertical Banded Gastroplasty for Morbid Obesity

Objective: The association between circulating vascular adhesion protein‐1 (VAP‐1) and metabolic phenotypes has been shown to be inconsistent. The current study explored whether the changes in serum VAP‐1 levels correlate with the changes in metabolic phenotypes after weight reduction surgery. Research Methods and Procedures: Clinical characteristics and serum VAP‐1 levels in 20 morbidly obese subjects (mean BMI 38.84 kg/m²) were measured before and after vertical banded gastroplasty. Results: Before surgery, serum VAP‐1 levels correlated positively with fasting plasma glucose (γ = 0.56, p = 0.01) and negatively with insulin levels (γ = ?0.51, p = 0.021). After surgery, the changes in serum VAP‐1 levels were negatively correlated with the changes in waist circumference (γ = ?0.57, p = 0.011), diastolic blood pressure (DBP) (γ = ?0.56, p = 0.015), and mean arterial pressure (γ = ?0.46, p = 0.055). In multivariate regression, serum VAP‐1 levels were negatively correlated with waist circumference (β = ?2.36, p = 0.014) and DBP (β = ?3.02, p = 0.017) after adjusting for age and gender. The change in DBP was negatively correlated with the change in VAP‐1 levels after adjusting for age, gender, and steady‐state plasma glucose. Discussion: The results suggest that VAP‐1 levels are correlated with fasting glucose and insulin levels in morbidly obese subjects. After surgery, the changes in VAP‐1 levels were associated with changes in visceral adiposity and DBP. Serum VAP‐1 might modulate DBP independently from the changes in insulin resistance in morbidly obese people.     

Increase in the Thermic Effect of Food in Women by Adrenergic Amines Extracted from Citrus Aurantium

Objective: To compare the thermic response to a meal between men and women of varied body composition and to determine whether adrenergic amines extracted from citrus aurantium (CA) induce an increase in metabolic rate and enhance the thermic response to the meal. Research Methods and Procedures: In 30 healthy weight‐stable subjects (17 women, 13 men; BMI: 20 to 42 kg/m²), body composition was determined by bioimpedance analysis followed by resting energy expenditure for 20 minutes, and the thermic effect of food (TEF) of a 1.7‐MJ, 30‐gram protein meal was determined intermittently for 300 minutes by indirect calorimetry. In a subset of 22 subjects, the TEFs of CA alone and when added to the same 1.7‐MJ meal were determined. Blood pressure and pulse before and throughout the studies and catecholamine excretion were determined. Results: TEF was significantly lower in women than men (152 ± 7 vs. 190 ± 12 kJ and 8.8 ± 0.4% vs. 11.0 ± 0.7% of meal), independently of age and magnitude of adiposity. The thermic response to CA alone was higher in men, but, when added to the meal, CA increased TEF only in women and to values no longer different from men. CA had no effect on blood pressure and pulse rate but increased epinephrine excretion by 2.4‐fold. Discussion: A 20% lower TEF in women suggests a diminished sympathetic nervous system response to meals, because with CA, TEF increased by 29% only in women. However, this acute response may not translate into a chronic effect or a clinically significant weight loss over time.     

Profile of Overweight and Obese People in a Mediterranean Region

Objective: To assess the prevalence of excess weight (obesity and overweight) and the related environmental risk factors in a Mediterranean population. Self‐perception of body weight, attitudes toward weight‐control behaviors, and the associated factors were also examined. Research Methods and Procedures: A cross‐sectional nutritional survey was carried out in the Balearic Islands between 1999 and 2000. A random sample (n = 1200) of the adult population (20 to 60 years old) was interviewed. Dietary questionnaires and a global questionnaire incorporating questions related to sociodemographic and lifestyle variables were utilized. Anthropometric measurements were also obtained. Results: Nearly one‐half of the population of the Balearic Islands is above the normal weight range (BMI > 25). The predictors of overweight and obesity in the Balearic Islands are to be over 40 years old, to be married, to form part of the lowest educational levels, and to have a sedentary lifestyle. A large percentage of excess‐weight individuals tend to underestimate their BMI, are not concerned about their weight status, tend to snack more often, and have never dieted. Discussion: Although the likely causes of the rise in obesity prevalence are difficult to elucidate from this study, we have identified the profile of individuals with excess weight in the Balearic Islands as well as their attitudes toward their body image.     

Kinetic Modeling of Amino Acid Oxidation Catalyzed by a New D‐Amino Acid Oxidase from Arthrobacter protophormiae

Amino acid oxidases, which enantiospecifically catalyze the oxidative deamination of either D‐ or L‐amino acids, belong to the class of oxidoreductases functioning with a tightly bound cofactor. This cofactor favors industrial applications of D‐amino acid oxidases (D‐AAO). Hence, the enzyme is very important for the industrial application in the purification and determination of certain amino acids. In developing the enzyme‐catalyzed reaction for large‐scale production, modeling of the reaction kinetics plays an important role. Therefore, the subject of this study was the kinetics of the oxidative deamination, a very complex reaction system, which is catalyzed by D‐AAO from Arthrobacter protophormiae using its natural substrate D‐methionine and the aromatic amino acid 3,4‐dihydroxyphenyl‐D‐alanine (D‐DOPA). The kinetic parameters determined by the measurement of the initial rate and nonlinear regression were verified in batch reactor experiments by comparing calculated and experimental concentration‐time curves. It was found that the enzyme is highly specific towards D‐methionine (K_m = 0.24 mM) and not as specific to D‐DOPA as a substrate (K_m = 9.33 mM). The enzyme activity towards D‐methionine ( = 3.01 U/mL) was approx. seven times higher than towards D‐DOPA ( = 20.01 U/mL). The enzyme exhibited no activity towards L‐methionine and L‐DOPA. Batch and repetitive batch experiments were performed with both substrates in the presence and in the absence of catalase for hydrogen peroxide decomposition. Their comparison made it possible to conclude that hydrogen peroxide has no negative influence on the enzyme activity.