Physiologia, Volume 3, Issue 1 (March 2023) – 11 articles

Plants are constantly interacting with the diverse microbial community as well as insect pests throughout their life cycle. Due to their sessile nature, plants rely solely on the intracellular signaling and reprogramming of cellular events to resist against pathogens. Insect pests are usually dependent on the nutrient-rich fluid obtained from plants or directly consume plant parts to sustain their life cycle. Plants possess a plethora of microbial communities; these microbiomes constantly influence the physiology, growth, development, and immunity in plants. Hence, the phyllosphere and rhizosphere are believed to play a major role in plant-insect interaction. The phyllosphere, rhizosphere, and endosymbiotic microbiome are currently under extensive scientific investigation. Recently, the advancement of metagenomic next-generation sequencing (mNGS) platforms revolutionized plant-associated microbiome analysis and has unveiled many beneficial microbial communities protecting against diverse pathogenic microorganisms and insect pests. Mycorrhiza is also an important component of the rhizosphere, as it may play a role in soil microbiota, thus indirectly influencing the interaction of insects with plants. In this regard, the present review tries to focus on some major insect pests of plants, the molecular mechanism of plant–insect interaction, and the probable role of phyllosphere and rhizosphere microbiome in this plant–insect encounter. This review is believed to open up a new dimension in developing resistance in plants against insect pests. Full article

There is a gap in the current knowledge on the immediate mechanisms of cardiovascular regulation in human subjects within short-term exposure to modeled microgravity using “dry” immersion. Aim. The purpose of the study was to evaluate cardiovascular responses in young healthy subjects during a 45 min session with the help of linear and nonlinear heart rate variability and hemodynamics parameters. The research voluntarily enrolled 33 subjects (18 men, 15 women) aged 19–23 years old. Results. The study showed that systolic and diastolic blood pressure was quite stable, some time-domain parameters of heart rate variability (SDNN, RMSSD, pNN50, etc.) and the frequency-domain (TP, HF, LF, but not VLF) have significantly increased within a 45 min “dry” immersion session. Of the non-linear parameters of heart rate variability, only ApEn significantly decreased during the “dry” immersion session. Conclusion. Our results suggest that a short-term 45 min DI session provokes in young healthy subjects neurogenic autonomic reaction based on the baroreceptor reflex. This provides stable hemodynamics in these subjects along the “dry” immersion session. Full article

Background: In sporting and combat settings, optimal fluid replacement is rarely achieved, exacerbating physiological strain. It is unknown if prescribed fluid replacement following exercise in heat impacts heart rate variability (HRV). Purpose: Compare prescribed drinking (PD) and ad libitum (AL) fluid replacement on HRV following exercise in heat. Methods: Twelve participants (26 ± 5 years, VO_2max: 58.44 ± 7.05 mL·kg⁻¹·min⁻¹) completed three trials in heat (36 °C, 36% humidity) on separate days, and were placed into groups, PD or AL. Recovery was assessed ~24 h later (hydration and HRV). HRV time and frequency was measured using a 3-lead electrocardiogram. Two-way repeated measures analysis of variance measured changes in HRV pre-trial, post-trial, and follow-up between groups. Data reported: p-value, mean difference (MD). Results: Fluid consumption was greater in PD during recovery (p = 0.012, MD = 1245 mL). Both groups were euhydrated at follow-up. HRV time (p < 0.001, MD = 24.23) and frequency (p < 0.001, MD = −1.98 ms²) decreased post-trial and increased by follow-up (time, p < 0.001, MD = −32.12; frequency, p < 0.001, MD = 2.38 ms²). HRV was similar between groups (p > 0.05). Conclusions: Replacing ≥60% fluid sufficiently rehydrates and restores HRV 24 h post-exercise in heat and mild dehydration (BML ≤ 3%). Prescribed fluid consumption during recovery was ~30% greater. Additional measures of recovery sensitive to heat strain may provide a more holistic understanding of specific mechanisms of recovery. Full article

Wnt signaling involves multiple pathways that contribute to organ development, cell fate, inflammation, and normal stem cell renewal and maintenance. Although the homeostasis of stem cells in the gastrointestinal (GI) tract highly depends on the Wnt signaling pathway, this regulation is impaired in cancers and in aging. Overactive (uncontrolled) Wnt signaling can induce GI epithelial cancers such as colon and gastric cancer. Overactive Wnt signaling can also contribute to the initiation and progression of gastrointestinal stromal tumor, which is the most common human sarcoma occurring in the walls of the digestive organs, mainly the stomach and small intestine. Wnt expression is positively associated not only with the progression of oncogenesis but also with resistance to chemotherapy and radiotherapy. Of note, recent reports show that decreased Wnt signaling is related to intestinal stem cell aging and that overactivated Wnt signaling leads to gastric pacemaker stem cell aging in tunica muscularis. These findings indicate that Wnt signaling has different crucial aspects of cell fate determination with age in GI tunica mucosa and muscularis. In this review, we summarize the most recent advances in our understanding of Wnt signaling pathways and their role in regulating key aspects during development, carcinogenesis, inflammation, and aging, with the ultimate goal of identifying novel therapies. Full article

Background: Secondary metabolites in stevia leaves offer important therapeutic benefits. The germination problems of stevia seeds and the high heterogeneity of the resulting populations make micropropagation the preferred tool for obtaining a large number of plants in a short time. Until now, studies have focused on optimizing the action of growth regulators for the improvement of stevia micropropagated plantlets. In this project, we study alternative mineral nutrients in the substrate and two culture systems on micropropagated stevia plantlets to obtain proper amounts of enhanced plantlets. Methods: Criolla and Morita varieties; MS, MSM, and G substrates, and temporary immersion (TIS) and agar-medium systems were used. Biometric variables and damage to the cell membrane of the resulting plantlets were tested. Results: More productivity in the Criolla plantlets growing in MS solid medium and TIS. The Morita plantlets presented higher productivity in the solid MS, MSM, and G substrates and TIS. The explants growing in MS and MSM presented the highest productivity. The solid substrate was generally better than TIS. No damage to the cell membrane was found. Conclusions: The micropropagation efficiency of stevia plantlets of the two varieties has been enhanced without negative effects on their physiological condition. Consequently, any of the culture systems used, including bioreactors, can be of industrial application on a large scale. Full article

Atrial fibrillation (AF) is characterized by disorganized rapid atrial electrical activity, which leads to impaired atrial function, adverse hemodynamic effects, and increased thromboembolic risk. The paroxysmal forms of AF can be effectively treated with current pharmacological and non-pharmacological modalities by targeting the arrhythmia triggers. Persistent AF, however, is more difficult to treat due to remodeling processes which may become major factors in the maintenance of the arrhythmia, rendering trigger-targeting treatment options less effective. We will systematically review the recent findings of the development and maintenance of persistent AF, including genetic, cellular, organ level, and systemic processes. As AF remains the most common sustained arrhythmia with the ongoing need to find effective treatment, we will also discuss potential treatment options targeting the remodeling processes. Full article

Background: Infections caused by multi-drug resistance (MDR) strains are potentially fatal public health issues worldwide that need pressing attention. Previous reports suggested using snake venom fractions as an effective alternative mechanism to the already available antibacterial drugs. In this study, we conducted a systematic review to analyze the bactericidal effects of snake venom phospholipases (PLA₂s). Methods: From the beginning through 30 March 2022, we searched the PubMed and Embase databases in accordance with the most recent PRISMA recommendations. We also conducted a manual search to identify relevant reports to improve literature coverage. Results: A total of 24 studies were included based on the selection criteria to compile this review. Of them, 16 studies were obtained from the abovementioned databases and eight through manual searches. The other 8 studies were obtained through the references of the included studies. According to the review, we reported that some PLA₂s showed more vigorous bactericidal activity on some Gram-negative and a moderate effect on Gram-negative and Gram-positive. Furthermore, we reported that the presence of p-bromophenacyl bromide (p-BPP) showed a significant decrease in enzymatic and associated antibacterial activities. Moreover, we observed that about 80% of the PLA₂s reported in our systematic review study were those from the Viperidae family, whereas 20% came from the Elapidae family. Moreover, some variations were revealed in the current study regarding the mechanism of actions of the snake venom PLA₂s (svPLA₂s). Conclusion: This systematic review provides a comprehensive overview of the bactericidal effect of snake venom PLA₂s and the analysis of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PLA₂s for bacterial strains. Varying bactericidal effects from various snake species and South American rattlesnakes were reported, presenting compelling concepts to the alternative search for therapies against bacterial resistance. Thus, further analysis of the bactericidal effects of other snake venoms PLA₂s considering different strains is needed. Moreover, more data are needed to investigate other bacteria of public health priority using peptides and other purified snake toxins. Full article

With colon cancer being one of the deadliest and most common cancers, understanding the mechanisms behind colon cancer is crucial in improving therapies. One of the newest approaches in cancer research is the concept of proteogenomics. While genomic data is not sufficient to understand cancer, the integration of multi-omics data including proteomics in conjugation with protein modeling has a better potential to elucidate protein structural alterations and characterize tumors. This enables a more efficient diagnosis of cancer and improves remedial strategies. In this review, we aim to discuss the linkage between gene mutations and protein structural alterations that lead to colon cancer. Topics include alterations in the glycoproteome and structures of proteases that impact colon cancer development. Additionally, we highlight the importance of precision oncology with an emphasis on proteogenomic approaches, protein modeling, and the potential impact on colon cancer therapy. Full article

Persons with multiple sclerosis (PwMS) experience a variety of physical impairments that can present in an asymmetrical pattern, resulting in significant differences between contralateral limbs (i.e., >10%). Asymmetries in PwMS have been associated with walking impairment and postural instability. Exercise intensity has been shown to influence the degree of asymmetry outcomes in healthy populations, and may have an impact on appropriate exercise prescriptions. The purpose of the current pilot study was to investigate the potential presence of asymmetry in metabolic events demarcating exercise intensity domains during single-leg cycling in PwMS. Five PwMS (Expanded Disability Status Scale range 2.0 to 4.5) completed a single leg incremental cycling test (SLICT) and a series of single-leg constant power time-to-exhaustion trials to determine gas exchange threshold (GET), peak oxygen consumption (VO₂peak), peak power output (PPO), critical power (CP), and W’ (exercise tolerance above CP) for both lower limbs. Statistical analysis revealed no significant between-limb differences for VO₂peak, GET, CP, PPO, and W’. Only W’ asymmetry score was significantly (49.5 ± 28.7 vs. 10.0, p = 0.04) greater than 10%. No significant differences between asymmetry scores at the GET, CP, and PPO were observed. Results from the current pilot investigation suggest that exercise intensity may not influence asymmetry outcomes in PwMS. Future studies with larger sample sizes and those with higher disability levels are required to fully understand the influence of exercise intensity on asymmetry in PwMS. Full article