Journal of Biosciences最新文献

Gut microbiota regulate host metabolism via its fermentation products, mainly short-chain fatty acids (SCFAs), i.e., acetate, propionate, and butyrate. Although butyrate is studied for its anti-inflammatory, anti-obesity, and anti-diabetic effects, propionate alone and in combination with acetate or butyrate is not well reported. In this study, we have shown the combinatorial effect of propionate with acetate or butyrate in the regulation of diabetes characteristics, liver metabolism, and inflammation via SCFA receptors and gut microbiota modulation. Diabetes was induced by high-fat diet administration for 4 months and was followed by oral administration of SCFAs for 1 month. Although propionate and butyrate alone showed reduced diabetic characteristics, a combination of propionate with acetate or butyrate more significantly regulated insulin downstream pathway molecules, i.e., liver X receptor (LXR), sterol regulatory element binding protein 1c (SREBP1c), glucose transporter type 4 (GLUT4), and peroxisome-proliferator-activated receptor alpha (PPARα), and enhanced the expression of SCFA receptors, i.e., G-protein-coupled receptor 41 (GPR41), GPR43, and GPR109 in the liver. They increased microbial richness and evenness along with the restoration of probiotic bacterial strains, healthy bacteria, as well as butyrate producers, mainly, Lactobacillus, Oscillospira, Barnesiella, Rikenellaceae_RC9_gut_group and Lachnospiraceae_NK4B4_group, Roseburia, Eubacteria, and Akkermensia. In conclusion, propionate in the presence of acetate or butyrate exerts beneficial effects on liver metabolism and inflammation via SCFA receptor modulation and gut microbiota alteration in the case of HFDinduced diabetic mice.

It is difficult to imagine a world without vision - eyes are everywhere around us. The evolution of vision has undeniably been one of the most profound events in the history of life on earth. Animals use their visual system to find food, shelter and mates, as well as in myriad other behaviours that enhance their fitness. On the other hand, vision is also an enemy for multitudes of prey animals that are hunted by visually-guided predators. For such prey animals, avoiding being perceived by the visual system of their potential predators is just as vital as is vision for predators. The earth has witnessed billions of prey species through evolutionary time, and today, some of the most striking adaptations are those that prey animals have evolved as a response to selection by predation. 'Camouflage' is an umbrella term that includes strategies to prevent detection or recognition (Ruxton et al. 2018). For instance, many prey match the colours and patterns of the background, i.e., background matching (Endler 1978). Others have colour patterns that break up the appearance of their body, i.e., disruptive colouration (Thayer 1909). Yet others closely resemble objects that are inedible to their predators, i.e., masquerade (Cott 1940). Camouflage can also involve other sensory systems such as olfaction such that chemically camouflaged prey may escape detection (Ruxton 2009).

Life on Earth is viable within a narrow window of physical parameters such as temperature, atmospheric pressure, oxygen concentration, etc. Fortunately, all these parameters are within that life-permissive window in most parts of our planet. Although most organisms cannot live beyond a limited range of these parameters, some fascinating lifeforms can survive, and some of them can even thrive, in extreme physical conditions beyond the optimal range. For example, Methanopyrus kandleri, a methanogenic archaeon, thrives at 122 °C (Takai et al. 2008). Archaea belonging to the genus Picrophilus can withstand pH values below 0.5 (Schleper et al. 1995). While just 5-10 Gy of radiation is fatal to humans, the bacterium Deinococcus radiodurans can tolerate 5000 Gy of radiation (Battista 1997; Krisko and Radman 2013).

The largest organ of the body, namely the skin, is a three-layer system composed of the epidermis, dermis, and subcutaneous tissue (Venus et al. 2010; Yousef et al. 2025). The outermost epidermis maintains the skin barrier and produces new skin cells and melanin. The middle layer, the dermis, contains glands, nerves, and blood vessels, providing strength and flexibility to the skin. The deepest fatty layer acts as the bridge between skin and underlying tissues. As with the gut microbiome, there is a plethora of microbes including bacteria, fungi, and viruses residing in the different layers of the skin, making up the skin microbiome (Chen and Tsao 2013; Swaney and Kalan 2021; Khan and Koh 2024). Skin microbiome composition varies by body site (Perez Perez et al. 2016; Bjerre et al. 2021) and factors such as age (Luna 2020), genetics (Si et al. 2015), and immunity (Belkaid and Segre 2014; Peroni et al. 2020). This diverse microbial ecosystem faces off challenges from invasive pathogens (Nakatsuji et al. 2021) and environmental aggressors such as some soaps (Mijaljica et al. 2022), UV radiation (D'Orazio et al. 2013; Tang et al. 2024), pollutants (Bocheva et al. 2023), and changes in temperature and humidity (Engebretsen et al. 2016).

The immune system is our defence network and primarily geared to protect us from pathogens and tumors. This aspect is evident in people who lack or possess a compromised immune system and are, therefore, highly susceptible to infections and development of cancer, as in AIDS patients (Nandi et al. 2020). However, healthy humans possess commensals in the gut and have developed a symbiotic relationship with these microbes. Indeed, we benefit from gut microbes that reside within us due to the production of microbial products such as vitamins, short-chain fatty acids, and other metabolites. As the gut flora changes with disease, information on the changed microbiome can be highly reflective of our health status (Shreiner et al. 2015). Recently, efforts have been directed towards better understanding of host responses towards commensals. While it is true that most of these efforts have focused on the gut, other organs have also been studied such as the respiratory tract and oral cavities. Two new studies have shed light on immune responses in the skin (Bousbaine et al. 2024; Gribonika et al. 2024). Why the skin? In fact, the skin is the largest and most well-exposed organ harboring immune capabilities to deal with several commensals (Belkaid and Segre 2014; Honda et al. 2019; Zhang et al. 2022). Most importantly, bacteria obtained from the skin in healthy humans are coated with antibodies, demonstrating host-directed immune responses (Metze et al. 1991); also, immunodeficient people are susceptible to skin infections (Lehman 2014). However, a detailed understanding of the players involved, and the extent of skin-directed immune responses in dealing with various microbes are lacking. Two recent papers have shed new light on immune responses in the skin utilizing high end flow cytometry, several strains of mutant mice and RNA seq (Bousbaine et al. 2024; Gribonika et al. 2024).

Clinical trial registries are invaluable resources for many stakeholders. However, these registries often require customized methodologies to identify studies of interest. To determine what steps it would take to catalog every trial that has run in India, in this study, we examined the records held by the registry of the United States, ClinicalTrials.gov. We utilized the Aggregate Analysis of ClinicalTrials.gov database, which draws data from ClinicalTrials.gov. Starting with 458,069 records, a shortlist of 11,439 records of interest was identified that contained the keywords 'India' or 'CTRI', the latter standing for Clinical Trials Registry-India. The Location field indicated that India had been a country of recruitment in 1,416 records. Other, non-obvious fields indicated that 52 records were concerned with trials in India. Among these, 35 cases used confirmatory language, and 17 cases had circumstantial evidence for the studies having run in India. It ought to be easier to unambiguously determine which countries a study has run in. Addressing this challenge is crucial for ensuring the accuracy, completeness, and transparency of clinical trial data, benefiting patients, healthcare providers, researchers, regulators, policymakers, and other stakeholders.

The neuromuscular junction (NMJ) is crucial for understanding the fundamentals of synaptic transmission and activity. Various modulators operate within neuronal circuits, from sensory to motor neurons, to influence synaptic transmission at the NMJ. This study sheds light on the regulation of sensory-evoked cholinergic neurotransmission at motor neurons orchestrated by CASY-1, the mammalian calsyntenin orthologue. We report that the increased excitation-inhibition (E-I) ratio at the NMJ in casy-1 mutants is likely due to its interactions with neuromodulators in sensory neurons. We explored the intricate genetic interactions of CASY- 1 with the neuropeptide FLP-21 and its receptor, NPR-1, both of which display simultaneous alterations in cholinergic signaling at the NMJ. Through genetic, pharmacological, and bioimaging-based experiments, we proposed a mechanism by which CASY-1 potentially interacts with the neuropeptide-carrying vesicles to regulate synaptic transmission. The nematode Caenorhabditis elegans serves as an ideal model system for this study, enabling detailed insights into neuromodulatory mechanisms in the neuronal circuit.

Morphogenesis is the process by which tissues and organs acquire their unique shapes and functions. Several cellular events, including cell shape changes, cell movement, cell proliferation, apoptosis, and others, act in concert to sculpt an organ. While these cellular behaviors are well-recognized to be essential for morphogenesis, whether organ-scale dynamics influence these cellular processes has remained unresolved. In a recent study published in Development, Tolkin et al. (2024) investigated the mechanisms underlying the dramatic morphogenesis of the distal tip cell (DTC), a leader cell and germline stem-cell niche in the Caenorhabditis elegans gonad (Byrd et al. 2014; Lee et al. 2016). They uncovered a novel 'hitch-and-tow' mechanism whereby germline flux drives a complex change in DTC shape. This work sheds light on how mechanical forces at the organ level influence cellular morphogenesis.

The discovery of antibiotics in the early to mid-1900s has shaped modern medicine. From treating bacterial infections to preventing them during surgeries or cancer therapy, antibiotics are an essential pillar of human health. Beyond therapeutics for humans, our ability to mass produce dairy or meat products relies on the protective shield that antibiotics provide against communicable bacterial diseases. Yet, even as modern societies started to reap the benefits of antibiotics, the threat of antibiotic resistance (more generally, antimicrobial resistance, or AMR) had emerged. As early as 1940, resistance to penicillin in Escherichia coli was reported (Abraham and Chain 1940). Very soon after its use to treat bacterial infections in clinics, resistance was also reported from Staphylococcus (Rammelkamp and Maxon 1942). The same story repeated with every new antibiotic over the next 80 years (Hutchings et al. 2019). Today AMR is widespread and has been dubbed a silent pandemic.

Recent studies have highlighted the involvement of repeat-derived transcripts in the pathological transcriptome of Alzheimer's disease (AD). However, it remains unclear whether these transcripts arise as a consequence of aging or are directly associated with AD pathology. Particularly, the specific contribution of satellite repeats to this phenomenon has not been systematically investigated. In this study, we profiled the non-coding expression patterns of all repetitive DNA elements - including satellites - across healthy young, healthy aged, and aged AD brain samples. Comparative transcriptome analysis revealed only a single differentially expressed repeat between aged and young brains. In contrast, AD brains exhibited significant expression changes in eight specific repeat elements relative to their healthy aged counterparts. Among these AD-specific repeats, the satellite repeat HSATII showed the highest fold change and a modest increase in histone acetylation levels, suggesting potential regulatory or feedback mechanisms in AD pathology. Weighted Gene Co-Expression Network Analysis (WGCNA) identified modules of co-expressed genes and repeats, revealing a network moderately correlated with the AD phenotype and indicating complex interactions between repeats and genes during disease onset. Collectively, our comprehensive analysis of repeat expression in post-mortem human AD brains demonstrates alterations in transposon and satellite repeat expression patterns that are distinct from agerelated changes.