Fluconazole worsened lung inflammation, partly through lung microbiome dysbiosis in mice with ovalbumin-induced asthma
Innate immunity in asthma may be influenced by alterations in lung microbiota, potentially affecting disease severity. This study investigates the differences in lung inflammation and microbiome between asthma-ovalbumin (OVA) administered with and without fluconazole treatment in C57BL/6 mice. Additionally, the role of inflammation was examined in an in vitro study using a pulmonary cell line. At 30 days post-OVA administration, allergic asthma mice exhibited increased levels of IgE and IL-4 in serum and lung tissue, higher pathological scores, and elevated eosinophils in bronchoalveolar lavage fluid (BALF) compared to control mice. Asthma inflammation was characterized by elevated serum IL-6, increased lung cytokines (TNF-α, IL-6, IL-10), and higher fungal abundance confirmed by polymerase chain reaction (PCR). Fluconazole-treated asthma mice displayed higher levels of cytokines in serum and lung tissue (TNF-α and IL-6), increased pathological scores, and a higher number of mononuclear cells in BALF, with undetectable fungal levels compared to untreated mice. Lung microbiome analysis revealed similarities between control and asthma mice; however, fluconazole-treated asthma mice exhibited higher Bacteroidota levels, lower Firmicutes, and reduced bacterial abundance. Pro-inflammatory cytokine production was increased in supernatants of the pulmonary cell line (NCI-H292) after co-stimulation with LPS and beta-glucan (BG) compared to LPS alone. Fluconazole treatment in OVA-induced asthma mice exacerbated inflammation, partially due to fungi and Gram-negative bacteria, as demonstrated by LPS+BG-activated pulmonary cells. Therefore, fluconazole should be reserved for treating fungal asthma rather than asthma caused by other etiologies.
Worasilchai et al. (2024) Fluconazole worsened lung inflammation, partly through lung microbiome dysbiosis in mice with ovalbumin-induced asthma. PeerJ 12:e18421 https://doi.org/10.7717/peerj.18421
Deciphering the influence of evolutionary legacy and functional constraints on the patella: an example in modern rhinoceroses amongst perissodactyls
In mammals, the patella is the biggest sesamoid bone of the skeleton and is of crucial importance in posture and locomotion, ensuring the role of a pulley for leg extensors while protecting and stabilizing the knee joint. Despite its central biomechanical role, the relation between the shape of the patella and functional factors, such as body mass or locomotor habit, in the light of evolutionary legacy are poorly known. Here, we propose a morphofunctional investigation of the shape variation of the patella among modern rhinoceroses and more generally among perissodactyls, this order of ungulates displaying a broad range of body plan, body mass and locomotor habits, to understand how the shape of this sesamoid bone varies between species and relatively to these functional factors. Our investigation, relying on three dimensional geometric morphometrics and comparative analyses, reveals that, within Rhinocerotidae and between the three perissodactyl families, the shape of the patella strongly follows the phylogenetic affinities rather than variations in body mass. The patellar shape is more conservative than initially expected both within and between rhinoceroses, equids and tapirs. The development of a medial angle, engendering a strong mediolateral asymmetry of the patella, appears convergent in rhinoceroses and equids, while tapirs retain a symmetric bone close to the plesiomorphic condition of the order. This asymmetric patella is likely associated with the presence of a “knee locking” mechanism in both equids and rhinos. The emergence of this condition may be related to a shared locomotor habit (transverse gallop) in both groups. Our investigation underlines unexcepted evolutionary constraints on the shape of a sesamoid bone usually considered as mostly driven by functional factors.
Mallet et al. (2024) Deciphering the influence of evolutionary legacy and functional constraints on the patella: an example in modern rhinoceroses amongst perissodactyls. PeerJ 12:e18067 https://doi.org/10.7717/peerj.18067
Co-applied biochar and drought tolerant PGPRs induced more improvement in soil quality and wheat production than their individual applications under drought conditions
Background Plant growth and development can be greatly impacted by drought stress. Suitable plant growth promoting rhizobacteria (PGPR) or biochar (BC) application has been shown to alleviate drought stress for plants. However, their co-application has not been extensively explored in this regard. Methods We isolated bacterial strains from rhizospheric soils of plants from arid soils and characterized them for plant growth promoting characteristics like IAA production and phosphate solubilization as well as for drought tolerance. Three bacterial strains or so called PGPRs, identified as Bacillus thuringiensis, Bacillus tropicus, and Bacillus paramycoides based on their 16S rRNA, were screened for further experiments. Wheat was grown on normal, where soil moisture was maintained at 75% of water holding capacity (WHC), and induced-drought (25% WHC) stressed soil in pots. PGPRs were applied alone or in combination with a biochar derived from pyrolysis of tree wood. Results Drought stress substantially inhibited wheat growth. However, biochar addition under stressed conditions significantly improved the wheat growth and productivity. Briefly, it increased straw yield by 25%, 100-grain weight by 15% and grain yield by 10% compared to the control. Moreover, co-application of biochar with PGPRs B. thuringiensis, B. tropicus and B. paramycoides further enhanced straw yield by 37–41%, 100-grain weight by 30–36%, and grain yield by 22–22.57%, respectively. The co-application also enhanced soil quality by increasing plant-available phosphorus by 4–31%, microbial biomass by 33–45%, and soil K+/Na+ ratio by 41–44%. Conclusion Co-application of PGPRs and biochar alleviated plant drought stress by improving nutrient availability and absorption. Acting as a nutrient reservoir, biochar worked alongside PGPRs, who solubilized nutrients from the former and promoted wheat growth. We recommend that the co-application of suitable PGPRs and biochar is a better technology to produce wheat under drought conditions than using these enhancers separately.
Malik et al. (2024) Co-applied biochar and drought tolerant PGPRs induced more improvement in soil quality and wheat production than their individual applications under drought conditions. PeerJ 12:e18171 https://doi.org/10.7717/peerj.18171
Myrmozercon mites are highly host specific: two new species of Myrmozercon Berlese associated with sympatric Camponotus ants in southern Quintana Roo, Mexico
Two new species of Myrmozercon, M. serratus sp. nov. and M. spatulatus sp. nov., are described based on adults and deutonymphs collected in association with ants in Mexico. They represent the first records of this genus from the Neotropic s.s. faunal region. Both new species are associated with hosts in the genus Camponotus from the same small area of a coastal lagoon, which share the same nesting habit preferences, providing strong evidence for host specificity. All but one colony of C. atriceps hosted mites, whereas they occurred in only half of the colonies of C. rectangularis. There was a significant positive correlation between the abundance of C. atriceps sexual ants and the abundance of mites. We summarize the known host associations for the genus Myrmozercon and discuss host specificity. Larvae of both mite species were collected on the wings of males and gynes suggesting that egg laying occurs on the hosts reproductive caste. Two hypotheses explaining this observation are discussed, larvae may be phoretic on winged sexuals, favoring mite co-dispersal with hosts, or larvae reside on the alates as a refuge from predation.
Pérez-Lachaud et al. (2024) Myrmozercon mites are highly host specific: two new species of Myrmozercon Berlese associated with sympatric Camponotus ants in southern Quintana Roo, Mexico. PeerJ 12:e18197 https://doi.org/10.7717/peerj.18197
Among the world’s smallest vertebrates: a new miniaturized flea-toad (Brachycephalidae) from the Atlantic rainforest
The genus Brachycephalus includes miniaturized toadlets with two distinct morphotypes: brightly colored species with a bufoniform phenotype and smaller, cryptic species with a leptodactyliform phenotype. The diversity of leptodactyliform species is still underappreciated, and we generally lack fundamental information about their biology. Recent sampling efforts, including DNA analyses and recordings of advertisement calls, have improved our understanding of this group. In the present study, we describe a new species of Brachycephalus, one of the smallest vertebrates known. This new species is distinguished from its congeners by a combination of morphological, bioacoustic, and genetic data. Despite being among the smallest frogs globally (the second smallest amphibian species), it exhibits skeletal traits typical of larger frogs, such as the presence of cranial bones that are lost or fused in other miniature frogs, including other Brachycephalus. Our description underscores how new discoveries within the megadiverse fauna of the Atlantic Forest—a rich biodiversity hotspot—can provide insights into phenotypic variation, including vertebrate body size. By describing this new species, we also aim to revisit the hypothesis that the type series of B. hermogenesi includes two species, potentially including individuals of the species described here.
Toledo et al. (2024) Among the world’s smallest vertebrates: a new miniaturized flea-toad (Brachycephalidae) from the Atlantic rainforest. PeerJ 12:e18265 https://doi.org/10.7717/peerj.18265
Comparative transcriptome analysis of cucumber fruit tissues reveals novel regulatory genes in ascorbic acid biosynthesis
Ascorbic acid (AsA) is one of the most abundant natural antioxidants, and it is an important indicator of the nutritional value of cucumber fruit. The aim of this study was to elucidate the regulatory mechanism affecting AsA metabolism in cucumber fruit. In this study, the AsA content in the fruit of two cucumber cultivars (H28 and H105) was significantly higher in the exocarp and endocarp than in the mesocarp. To clarify the regulation of AsA in cucumber fruit, the transcriptomes of three fruit tissues (i.e., the exocarp, mesocarp, and endocarp) of two cucumber cultivars (H28 and H105) were sequenced. Transcriptomic profiling combined with transcription factors (TFs) and correlation analysis were performed to reveal that three genes, including CsaV3_5G014110 (phosphomannomutase, PMM), CsaV3_2G004170 (GDP-mannose-3′, 5′-epimerase, GME) and CsaV3_5G006680 (dehydroascorbate reductase, DHAR), were expressed at higher level in the exocarp and endocarp than in the mesocarp. In both two cultivars, CsaV3_4G028360 (ethylene-responsive transcription factor, ERF) was negatively correlated with PMM and GME, and positively correlated with DHAR. CsaV3_6G042110 (ethylene-responsive transcription factor, ERF) was positively correlated with PMM and GME, and negatively correlated with DHAR. CsaV3_6G032360 (mitogen-activated protein kinase, MAPK) as positively correlated with PMM, GME and DHAR. These six genes are considered the key candidate genes for further research. This study provides insight for further study on the regulation of AsA biosynthesis in cucumber fruit and provide potential candidate genes for future genetic improvement of cucumber germplasm with enhanced AsA accumulation.
Ren et al. (2024) Comparative transcriptome analysis of cucumber fruit tissues reveals novel regulatory genes in ascorbic acid biosynthesis. PeerJ 12:e18327 https://doi.org/10.7717/peerj.18327
Antimicrobial and anti-endotoxin activity of N-acetylcysteine, calcium hydroxide and their combination against Enterococcus faecalis, Escherichia coli and lipopolysaccharides
Background The management of endodontic infections is a complex challenge, mainly due to the involvement of diverse microorganisms and their by-products. This study aimed to evaluate the efficacy of N-acetylcysteine (NAC), calcium hydroxide (Ca(OH)2), and their combined application as intracanal medications in combating Enterococcus faecalis, Escherichia coli, and lipopolysaccharides (LPS) from E. coli. Methods A total of 60 single-rooted human teeth were carefully selected and divided into six groups. These tooth canals were deliberately exposed to E. faecalis (ATCC 29212) and E. coli (ATCC 25922) to induce biofilm formation. Subsequently, the specimens were treated with NAC, Ca(OH)2, or a combination of both substances. Three samples of the root canals were collected at three moments: the first sample (S1) was to confirm the initial contamination, the second sample (S2) was immediately post-instrumentation, and the third sample (S3) was collected after the use of the intracanal medication. The antimicrobial efficacy of these intracanal medications was assessed by enumerating colony-forming units per milliliter (CFU/mL). In addition to this, the kinetic chromogenic Limulus Amebocyte Lysate (LAL) assay by Lonza was used to quantify LPS from E. coli. Data tested for normality; then, Kruskal-Wallis and Friedman tests were used, and Dunn’s for multiple comparisons. Results The findings of this study showed significant reductions in the microbial load of E. faecalis and E. coli by S3. Notably, there were no statistically significant differences among the treatment groups concerning these microorganisms. However, it was observed that only the combination of NAC and Ca(OH)2 led to a noteworthy decrease in the quantity of E. coli’s LPS after 7-days, demonstrating a statistically significant difference from the other treatment groups. NAC + Ca(OH)2 combination, applied for a duration of 7-days, proved to be more suitable in reducing the presence of E. faecalis, E. coli, and LPS from E. coli within the context of endodontic infections.
Khoury et al. (2024) Antimicrobial and anti-endotoxin activity of N-acetylcysteine, calcium hydroxide and their combination against Enterococcus faecalis, Escherichia coli and lipopolysaccharides. PeerJ 12:e18331 https://doi.org/10.7717/peerj.18331
House sparrows do not show a diel rhythm in double-strand DNA damage in erythrocytes
DNA damage can be caused by a number of intrinsic and extrinsic factors. A recent study showed that free-living house sparrows (Passer domesticus) have higher DNA damage in the summer than the winter across five different tissues. This result was consistent when house sparrows were brought into captivity and exposed to comparable light cycles, with all other variables held constant. These results generated two hypotheses: (1) seasonal variation in DNA damage is related to circadian regulation and (2) seasonal variation in DNA damage is related to the total number of active hours. To investigate these hypotheses, we first quantified erythrocyte DNA damage in wild-caught house sparrows held in captivity on a 12L:12D light cycle at six points during the day to assess a diel or circadian rhythm but did not find one. We then performed a resonance experiment, in which birds experienced unnatural light cycles, and compared DNA damage in birds held on 6L:6D and 4.5L:7.5D resonance light cycles with their natural counterparts, 12L:12D and 9L:15D, respectively. We assessed corticosterone levels and DNA damage in blood before and after the resonance light cycles and DNA damage in abdominal fat, hippocampus, hypothalamus, and liver after the resonance light cycles. While our second experiment was not able to effectively test our hypotheses, we were able to demonstrate some interesting patterns. Throughout the resonance experiment, baseline corticosterone and testes size increased, consistent with the birds being photostimulated and preparing to breed. Surprisingly, the direction of change of DNA damage throughout the resonance photoperiod differed with tissue, which is not consistent with patterns during the breeding season in the wild. Our data indicate a potential uncoupling of the breeding physiology with the effect on DNA damage due to exposure to a resonance light cycle, which the birds may have interpreted as a skeleton photoperiod. Finally, though we were unable to fully disentangle the dynamics underlying seasonal DNA damage, we show that the previously documented patterns are not simply due to diel changes or the total amount of light exposure within a 24-hour period.
Rosen et al. (2024) House sparrows do not show a diel rhythm in double-strand DNA damage in erythrocytes. PeerJ 12:e18375 https://doi.org/10.7717/peerj.18375
The regulation role of calcium channels in mammalian sperm function: a narrative review with a focus on humans and mice
Mammalian sperm are characterized as specialized cells, as their transcriptional and translational processes are largely inactive. Emerging researches indicate that Ca2+ serves as a crucial second messenger in the modulation of various sperm physiological processes, such as capacitation, hyperactivation, and the acrosome reaction. Specifically, sperm-specific calcium channels, including CatSper, voltage-gated calcium channels (VGCCs), store-operated calcium channels (SOCCs), and cyclic nucleotide-gated (CNG) channels, are implicated in the regulation of calcium signaling in mammalian sperm. Calcium stores located in the sperm acrosomes, along with the IP3 receptors in the neck of the redundant nuclear envelope and the mitochondria in the tail, play significant roles in modulating intracellular Ca2+ levels in sperm. However, the functions and mechanisms of these calcium channels in modulating mammalian sperm physiological functions have not yet been well elucidated. Therefore, by focusing on humans and mice, this study aims to provide a comprehensive review of the current advancements in research regarding the roles of calcium signaling and associated calcium channels in regulating sperm function. This endeavor seeks to enhance the understanding of calcium signaling in sperm regulation and to facilitate the development of drugs for the treatment of infertility or as non-hormonal male contraceptives.
Yang et al. (2024) The regulation role of calcium channels in mammalian sperm function: a narrative review with a focus on humans and mice. PeerJ 12:e18429 https://doi.org/10.7717/peerj.18429
Bacterial production of polyhydroxyalkanoates (PHAs) using various waste carbon sources
Synthetic plastics are in great demand in society due to their diversified properties, but they cause environmental pollution due to their non-biodegradable nature. Therefore, synthetic plastics are in need to be replaced with biodegradable plastics. Polyhydroxyalkanoates (PHAs), bacterial biopolymers are natural alternative to synthetic plastics. These are present inside the bacterial cytoplasm in granular form. Presently, the production cost of PHA is high due to expensive carbon substrates used in its biosynthesis. Therefore, this study focuses on the cost-effective production of PHA using waste carbon sources. Rice bran and sugarcane molasses were used as the carbon source for PHA production from Bacillus subtilis, Bacillus cereus, Alcaligenes sp. and Pseudomonas aeruginosa. PHA production from these bacterial strains was confirmed through Sudan Black-B screening. With rice bran, as carbon source, the highest PHA yield obtained was for P. aeruginosa, which yielded 93.7% and lowest was 35.5% for B. cereus. Surprisingly, B. cereus produced the highest cell dry mass (0.045 g/L) but its extracted PHA contents were lowest being only 0.02 g/L. Alcaligenes sp. with 0.031 g/L CDM yielded 87.1% PHA. B. subtilis had a CDM 0.029 g/L, 0.02 g/L PHA content and a yield of 69.10%. In the case of sugarcane molasses, P. aeruginosa produced 95% PHA yield, 0.02 g/L CDM, and 0.019 g/L PHA content. Alcaligenes sp. yielded 90.9% PHA, 0.011 g/L CDM, and 0.01 g/L PHA content. B. subtilis produced 91.6% PHA yield, 0.012 g/L CDM, 0.011 g/L PHA content; B. cereus produced 80% PHA yield, 0.015 g/L CDM, 0.012 g/L PHA content at 37 °C, pH 7. Higher concentrations of carbon sources increased the CDM and decreased the PHA yield. The maximum yield of PHA was obtained from sugarcane molasses. 24–48 h of incubation was optimal for B. subtilis and B. cereus, while for Alcaligenes and P. aeruginosa incubation time of 48–96 h was desirable for higher PHA yield. The extracted biopolymers were analyzed by Fourier transform infrared spectroscopy (FTIR), which identified the extracted biopolymers as poly-3-hydroxybutyrate P(3HB). The thermal properties of the extracted biopolymers, such as melting temperatures, were analyzed by differential scanning calorimetry (DSC), which confirmed the thermal stability.
Naseem et al. (2024) Bacterial production of polyhydroxyalkanoates (PHAs) using various waste carbon sources. PeerJ 12:e17936 https://doi.org/10.7717/peerj.17936