Single-Cell and Single-Molecule Studies of Bacteriophage Lambda Post-Infection Decision-Making

Cellular decision making is a ubiquitous process among all life forms, and a key step that organisms take to integrate the environmental signals to choose an optimal response to improve their overall fitness. The genetic circuits selected to carry out this task determine the cell fate in a seemingly probabilistic way, either due to the inherent stochasticity of the system, or our inability to characterize the factors with deterministic impacts. To gain a better understanding of the mechanisms underlying cell-fate selection, we utilize a well-established system for cellular decision-making, the paradigm of bacteriophage lambda infection, which leads to two distinct outcomes – lysis and lysogeny. Recent studies of this system using higher resolution techniques suggested that different phage decisions are partially determined by pre-existing difference and the complex in vivo phage-phage interactions. Therefore, characterizing more ‘hidden’ deterministic factors and dissecting the intracellular behaviors of phage components, such as DNA, RNA and proteins are central to a more complete understanding of the phage decision-making strategies. One commonly overlooked but potentially important factor is phage DNA replication, which could result in not only more templates for gene expression but also introduce gene copy number variations. Meanwhile, although theoretical work has long predicted that noise arising from stochastic gene expression can be propagated through the gene networks to result in phenotypic variance, experimental characterization is still lacking, impeding the assessment of its contributions to phage decision-making. In this work, we provided direct experimental evidence that different phage DNAs are capable of making decisions independently. DNA integration, a characteristic event for phage lysogenization, can also be detected in lytic cells. Moreover, through single phage DNA labeling technique, we revealed great heterogeneity in intracellular DNA motions, which could partially explain the complex phage-phage interactions. Furthermore, we found that DNA replication is important for the enforcement of decisions. Instead of affecting the transcription of early lysis-lysogeny decision-making genes, DNA replication exerts its effect on the expression of the decision effectors, CI. Lastly, a mathematical model is built to provide comprehensive understanding of the decision making network

Triple positive solutions for semipositone fractional differential equations m-point boundary value problems with singularities and p–q-order derivatives

In this paper, by means of Leggett–Williams and Guo–Krasnosel'skii fixed point theorems, together with height functions of the nonlinearity on different bounded sets, triple positive solutions are obtained for some fractional differential equations with p–q-order derivatives involved in multi-point boundary value conditions. The nonlinearity may not only take negative infinity but also may permit singularities on both the time and the space variables

Cell fate decisions emerge as phages cooperate or compete inside their host

The system of the bacterium Escherichia coli and its virus, bacteriophage lambda, is paradigmatic for gene regulation in cell-fate development, yet insight about its mechanisms and complexities are limited due to insufficient resolution of study. Here we develop a 4-colour fluorescence reporter system at the single-virus level, combined with computational models to unravel both the interactions between phages and how individual phages determine cellular fates. We find that phages cooperate during lysogenization, compete among each other during lysis, and that confusion between the two pathways occasionally occurs. Additionally, we observe that phage DNAs have fluctuating cellular arrival times and vie for resources to replicate, enabling the interplay during different developmental paths, where each phage genome may make an individual decision. These varied strategies could separate the selection for replication-optimizing beneficial mutations during lysis from sequence diversification during lysogeny, allowing rapid adaptation of phage populations for various environments

Efficacy of Baduanjin for obesity and overweight: a systematic review and meta-analysis

BackgroundAccording to data from the World Health Organization (WHO), there is a significant public health issue regarding the increasing number of individuals affected by obesity and overweight on an annual basis. Therefore, it is imperative to urgently identify interventions that can effectively control and improve this condition. Baduanjin, as a medium-intensity exercise, appears a suitable approach for weight reduction among individuals with obesity. This paper aimed to provide a systematic review and meta-analysis of the efficacy of Baduanjin in addressing obesity and overweight, with the ultimate goal of assisting individuals with obesity in finding an effective, safe, and engaging method for weight reduction.MethodsWe conducted a comprehensive search of multiple databases including PubMed, Cochrane Library, Web of Science, Embase, The China National Knowledge Infrastructure (CNKI), The Chinese Scientific Journal Database (VIP), The Chinese Biomedical Literature Database (CBM), and WanFang Database to identify relevant articles published from the inception of each database until September 2023. Specifically, we focused on randomized controlled trials (RCTs) investigating the effects of Baduanjin on weight reduction. Data from these studies were extracted and analyzed using appropriate statistical methods. In cases where there was no significant heterogeneity (I2 < 50%, p > 0.1), we employed a fixed effects model for data synthesis; otherwise, a random effects model was selected. Funnel plots were used to assess publication bias, and the mean difference (MD) was reported as an indicator of treatment group differences.ResultsA total of 420 participants were included in 10 studies. The MD results of the experimental group when compared with the control group were −3.69 (95%CI = −4.97 to −2.40, p < 0.001) for body weight (BW), −5.42 (95%CI = −6.56 to −4.28, p < 0.001) for body mass index (BMI), −1.36 (95%CI = −1.76 to −0.96, p < 0.001) for waist circumference (WC), −3.40 (95%CI = −4.43 to −2.37, p < 0.001) for hip circumference (HC), and −0.03 (95%CI = −0.04 to −0.02, p > 0.1) for the waist-to-hip ratio (WHR). All of the values in the experimental group showed significant difference. The results of the Egger’s test (t = 1.43, p = 0.190) suggest that there was no substantial bias present within the data analysis process. The safety profile revealed no adverse events reported across all 10 studies.ConclusionBaduanjin could be effective in reducing weight, and the practice of Baduanjin has the potential to regulate BW, BMI, WC, HC, and WHR. However, further well-designed RCTs are still necessary to provide more robust evidence in the future.Systematic review registrationhttp://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024513789

Improving the Stability of Insulin in Solutions Containing Intestinal Proteases in Vitro

Degradation of insulin was studied in this work. Casein and protamine could obviously suppress degradation of insulin by intestinal enzymes, and could protect insulin from degradation by the mechanism of competition and combination with proteolysis enzyme. What is more, co-incubated with HP-β-CD-casein or HP-β-CD-protamine, most insulin was protected from degradation by intestinal enzymes. In addition, it was found that the complexation of insulin with HP-β-CD was characterized by UV absorption spectra. These results indicated that HP-β-CD, casein and protamine could offer some positive and useful results, and could protect insulin from degradation during their transit through the intestinal tract

Coupling of DNA Replication and Negative Feedback Controls Gene Expression for Cell-Fate Decisions

Summary: Cellular decision-making arises from the expression of genes along a regulatory cascade, which leads to a choice between distinct phenotypic states. DNA dosage variations, often introduced by replication, can significantly affect gene expression to ultimately bias decision outcomes. The bacteriophage lambda system has long served as a paradigm for cell-fate determination, yet the effect of DNA replication remains largely unknown. Here, through single-cell studies and mathematical modeling we show that DNA replication drastically boosts cI expression to allow lysogenic commitment by providing more templates. Conversely, expression of CII, the upstream regulator of cI, is surprisingly robust to DNA replication due to the negative autoregulation of the Cro repressor. Our study exemplifies how living organisms can not only utilize DNA replication for gene expression control but also implement mechanisms such as negative feedback to allow the expression of certain genes to be robust to dosage changes resulting from DNA replication. : Gene Network; Microbial Genomics; Bioinformatics; Mathematical Biosciences Subject Areas: Gene Network, Microbial Genomics, Bioinformatics, Mathematical Bioscience

Antecubital vein combined with femoral vein pathway could shorten the learning curve of simultaneous bilateral adrenal vein sampling

Abstract During our previous bilateral adrenal vein sampling (AVS) procedure, the authors observed that accessing the left adrenal vein through the antecubital vein was more feasible than the conventional femoral vein. Meanwhile, the femoral vein pathway facilitated access to the right adrenal vein than the antecubital vein pathway. Therefore, the authors hypothesized that simultaneous bilateral AVS via the antecubital combined with the femoral vein pathway could improve the success rate. A total of 94 cases of AVS via the antecubital combined with the femoral vein pathway were performed, while the remaining 20 cases employed the antecubital vein pathway at our center between August 2020 and April 2023. Furthermore, a meta‐analysis was conducted in this study using 15 selected articles to determine the success rate of AVS in each center and pathway. The success rate of ACTH‐stimulated simultaneous bilateral AVS via the antecubital vein combined with the femoral vein pathway was 92.85% (P = .503) on the right and 95.00% (P < .001) on the left. In the antecubital vein pathway, the success rates were only 25.00% (P < .001) on the right side and 80.00% (P = .289) on the left side. The results of meta‐analysis demonstrated a success rate of 78.16% on the right and 94.98% on the left for ACTH‐stimulated AVS via the femoral vein pathway. Based on our center's experience, simultaneous bilateral adrenal vein sampling via the combined pathway could improve the success rate of AVS in the short term and shorten the learning curve

Improved Glucose-Stimulated Insulin Secretion by Selective Intraislet Inhibition of Angiotensin II Type 1 Receptor Expression in Isolated Islets of db/db Mice

Recent evidence supported the presence of a local renin-angiotensin system (RAS) in the pancreas, which is implicated in many physiological and pathophysiological processes. We utilized small interfering RNA (siRNA) to investigate the effects of angiotensin II type 1 receptor (AT1R) knockdown on glucose-stimulated insulin secretion (GSIS) in isolated islets of db/db mice and to explore the potential mechanisms involved. We found that Ad-siAT1R treatment resulted in a significant decrease both in AT1R mRNA level and in AT1R protein expression level. With downexpression of AT1R, notable increased insulin secretion and decreased glucagon secretion levels were found by perifusion. Simultaneously, significant increased protein levels of IRS-1 (by 85%), IRS-2 (by 95%), PI3K(85) (by 112.5%), and p-Akt2 (by 164%) were found by western blot. And upregulation of both GLUT-2 (by 190%) and GCK (by 121%) was achieved after AT1R inhibition by Ad-siAT1R. Intraislet AT1R expression level is a crucial physiological regulator of insulin sensitivity of β cell itself and thus affects glucose-induced insulin and glucagon release. Therefore, the characteristics of AT1R inhibitors could make it a potential novel therapeutics for prevention and treatment of type 2 diabetes

Trichoderma-secreted anthranilic acid promotes lateral root development via auxin signaling and RBOHF-induced endodermal cell wall remodeling

Summary: Trichoderma spp. have evolved the capacity to communicate with plants by producing various secondary metabolites (SMs). Nonhormonal SMs play important roles in plant root development, while specific SMs from rhizosphere microbes and their underlying mechanisms to control plant root branching are still largely unknown. In this study, a compound, anthranilic acid (2-AA), is identified from T. guizhouense NJAU4742 to promote lateral root development. Further studies demonstrate that 2-AA positively regulates auxin signaling and transport in the canonical auxin pathway. 2-AA also partly rescues the lateral root numbers of CASP1pro:shy2-2, which regulates endodermal cell wall remodeling via an RBOHF-induced reactive oxygen species burst. In addition, our work reports another role for microbial 2-AA in the regulation of lateral root development, which is different from its better-known role in plant indole-3-acetic acid biosynthesis. In summary, this study identifies 2-AA from T. guizhouense NJAU4742, which plays versatile roles in regulating plant root development