Biologia最新文献

Here, the effects of previously characterized poly(HEMA-N-vinyl formamide) (PHEMA-NVF) cryogels on viability, surface morphology, total antioxidant-oxidant status, antioxidant enzyme activities, and biochemical makeup of Saccharomyces cerevisiae were investigated for the first time. The cells' viability from the PHEMA-NVF cryogels exhibited a significant drop of 23.96 ± 1.44% compared to the plain PHEMA cryogel, which served as the control group without NVF. Additionally, this cryogel caused blebbing and holes on the cell surface. Despite the gradual increase in TOS levels with increasing NVF amounts, only the cryogel containing 3.12 mmol NVF showed a statistically significant difference from the control. The gradual increases in TAS levels in response to cellular stress were recorded depending on the increase in NVF amounts up to 3.12 mmol. While the enzymatic antioxidant system was generally induced in cells released from the cryogel prepared with relatively low levels of NVF, these activities dramatically decreased at higher amounts of the comonomer. Finally, FTIR analysis revealed that the highest concentration of NVF caused protein degradation and increased the relative concentration of lipid and polysaccharide molecules. Therefore, we can suggest that this comonomer induces oxidative stress, which the cell cannot tolerate beyond a certain threshold.

Graphical Abstract

Chaetognatha, the second-most abundant zooplankton in the marine ecosystem, is a connecting link between copepods and organisms of the higher trophic level. The present checklist provides detailed information on the morphology and distribution of chaetognaths in the eastern Arabian Sea (northeastern Arabian Sea, southeastern Arabian Sea, and Laccadive Sea). It includes five families under two orders with 34 species belonging to 15 genera and recorded from both shelf, oceanic and deep sea waters of the eastern Arabian Sea, creating a first line data on chaetognaths of the Arabian Sea.

Georgia is part of two biodiversity hotspots, the Caucasus and the Irano-Anatolian, both of which are characterized by high biological diversity and endemism rates. Eighty-one species of small mammals (Eulipotyphla, Chiroptera, Rodentia, and Leporidae) have been recorded in Georgia so far based on morphological identification. However, a comprehensive understanding of small mammal diversity requires integrative taxonomic approaches due to the cryptic nature and sympatric distribution of some taxa. Here, to develop a DNA barcode library, we re-evaluated the small mammal diversity of Georgia.

Samples for DNA studies were collected during the last nine years throughout Georgia. The Cytochrome Oxidase Subunit I (COI) region of the mitochondrial genome was barcoded for collected samples, and a DNA barcode library was assembled. As a result, nearly 80% of the known species of Georgian small mammals were covered. Two species, Microtus rossiaemeridionalis (Ognev, 1924) and Myotis tschuliensis (Kuzyakin, 1935), were detected for the first time in Georgia. Furthermore, several problems were identified within the Chiroptera and Rodentia orders, requiring further studies.

The lack of precise data on the environmental requirements of the conspicuous fungus with a northern distribution limit in Slovakia, Pogonoloma macrorhizum, initiated our study. Its identity was verified by sequencing of ITS and 28 S nrDNA regions. The analysis of trophic status by stable-isotope ratio of carbon and nitrogen suggested that the species is probably ectomycorrhizal. For the seventeen sampling sites, environmental data were obtained and information on landscape development and management were retrieved from historical maps and aerial orthophotographs. All these parameters were analysed by multivariate ordination methods. In Slovakia, P. macrorhizum is found in thermophilous to mesophilous stands on acidic soils with a pH ranging from 4.1 to 6.2. These habitats are dominated by Quercus cerris, with non-frequent tree taxa of Carpinus betulus and Quercus petraea agg. The key environmental drivers shaping the habitat of P. macrorhizum were identified as time since deforestation, with the presence of old Q. cerris individuals (former solitary trees of pastures) and soil characteristics. The fungus appears to be a species of transitional habitats historically affected by grazing. These transitions occur between thermophilic and mesophilic sites, including oak forest communities, dry steppic grasslands and forest edges, as well as spontaneously overgrown pastures and forests with a closed canopy. It is regrettable that the Q. cerris stands in Slovakia are under threat, particularly because of felling and the lack of grazing in forests. Furthermore, recent silvicultural practices have resulted in the replacement of oaks (Quercus spp.) by hornbeam (Carpinus betulus) and the formation of closed stands.

Non-indigenous invasive topmouth gudgeon (Pseudorasbora parva) was introduced to Europe in 1960s and it has passed an ongoing invasion into many European countries. It forms numerous populations particularly in pond aquaculture systems and small stagnant water bodies. The study was carried out on a 0.3 ha pond inhabited solely by the population of topmouth gudgeon. Monthly samplings of environmental variables, zooplankton, macrozoobenthos and fish were performed in 2016–2017. Topmouth gudgeon recruitment correlated with decrease of oxygen concentration and transparency in summer months, apparently due to topmouth gudgeon predation on the cladocerans. The macrozoobenthos community was dominated by large chironomid larvae (Chironomus plumosus), whose density and biomass were not affected by the topmouth gudgeon population. The habitat preferences varied within the population. The 0 + age cohort were abundant in rocky rip-rap, muddy and macrophyte habitats with low abundance in free water zone. In contrast, the 1 + and older fish significantly preferred the rocky rip-rap habitat and free water zone over muddy and macrophyte substrates. In spring, the rocky rip-rap was occupied mainly by males, while later in June and July, females predominated in this habitat. The study also documented disapperance of topmouth gudgeon population due to sudden spate flash-flood.

Metal nanoparticles (MNPs) have gained considerable attention for their diverse applications across various fields, including medicine, electronics, and environmental remediation, agriculture and manufacturing. The relationship between metal nanoparticles and the microorganisms, highlighting the diverse mechanisms through which nanotoxicity manifests and influences microbial communities. Metal nanoparticles, owing to their unique physicochemical properties, can interact with the microbiome directly or indirectly, disrupting microbial homeostasis and functionality. The interactions are complex, involving mechanisms such as membrane disorganization, reactive oxygen species (ROS) generation, and oxidative Deoxyribonucleic acid (DNA) damage. Comprehending the different types of metal nanoparticles, their antimicrobial properties, and the mechanisms that underlie their nanotoxicity towards microorganisms is imperative for the secure advancement and implementation of nanotechnology, paving the way for innovative strategies to mitigate adverse effects and promote sustainable nanomaterial applications. Nanotechnology has witnessed remarkable advancements in various fields, yet concerns regarding its potential adverse effects on biological systems, particularly the microbiome, have emerged as a significant area of investigation. This abstract highlight the importance of interdisciplinary approaches encompassing nanoscience, microbiology, and toxicology to unravel the intricate dynamics of metal nanoparticle-microbes’ interactions and facilitate the design of safer nanoproducts for diverse applications. Overall, this study emphasizes the need for more investigation to clarify the complex dynamics of metal nanoparticles in microbial environments and their long-term effects on sustainability and environmental health.

Mechanoreceptor organs in hemimetabolous insects are physiologically important not only in the adult insects, but also for sensory functions in the juvenile postembryonic stages. They provide proprioceptive and exteroceptive information, e.g., in locomotion or orientation. In stick insects (Phasmatodea), the subgenual organ complex in the tibia of all legs is an elaborate mechanoreceptor system. This complex contains two chordotonal organs, the subgenual organ and the distal organ. These organs have mainly been studied in adult insects for the neuroanatomy and functional morphology. Here, the sensory organs were investigated in newly hatched Ramulus artemis (Westwood, 1859) to indicate the functional organisation at the beginning of postembryogenesis, when the detection of mechanical stimuli becomes relevant for behaviour. The organs were investigated by axonal tracing for the organ neuroanatomy, innervation, and number of sensilla in the distal organ. In addition, the sensory complex was analysed for the connection by a membrane between the organs. The organs are present after hatching, indicating in particular a possible vibration detection by the subgenual organ. In most cases, the connection between the sensory organs was also present. This indicates the development of sensory neurons and additional tissues during embryogenesis. The sensory neurons in the subgenual organ show a re-organisation, as the dorsal sensilla change from orientation in distal directions to proximal directions. This finding is discussed for implications in vibration detection. The overall results indicate some neuroanatomical modifications during postembryonic development, while the main structures of the subgenual organ complex already originate during embryonic development.

Phallocryptus spinosus (Milne-Edwards, 1840) and Branchinectella media (Schmankewitsch, 1873) are two anostracan species co-occurring in several saline lakes of the eastern steppic zone of Algeria. Both species produce resting eggs to persist in their temporary and unstable habitats, constituting a resting eggs bank. B. media has a wide and scattered distribution area, and it is known to prefer cold temperatures (16 °C max). Resting egg banks and hatching patterns of both species have been assessed in seven saline lakes. Results showed that densities of P. spinosus resting eggs were always higher than those of B. media, whatever the lake (F = 4.66, p = 0.0005). They range between 93,000 ± 75 and 1,495,000 ± 366.5 resting eggs m⁻² for P. spinosus, and between 670 ± 30 and 365,000 ± 268 resting eggs m⁻² for B. media. Hatching percentages of eggs incubated at temperatures of 16 °C and 22 °C, and salinities of 0 and 5 psu, showed that 16 °C and 5 psu was the most suitable combination for B. media, since 38.88 ± 1.93% of eggs hatched under these conditions. For P. spinosus, 81.11 ± 1.92% of eggs hatched at 22 °C and 5 psu. Resting eggs diameters measurements of both species as well as scanning electron micrographs of B. media are provided.

Wheat plants infested by Russian wheat aphids (RWA) induce a cascade of defence responses, which include increased activity of β-1,3-glucanase and peroxidase (POD). There is a lack of information regarding β-1,3-glucanase and POD synergistic effects on the plant cell wall modification and characterisation during wheat-RWA infestation. This study aimed to characterise the physicochemical properties of the cell wall-bound POD and β-1,3-glucanase during RWA-wheat interaction. The susceptible Tugela, moderately resistant Tugela-Dn1, and resistant Tugela-Dn5 cultivars were planted in a glasshouse to a seedling stage before being infested with RWASA2 for 14 days. The findings showed a significant increase in β-1,3-glucanase and POD activities in the infested Tugela-Dn5 and Tugela-Dn1 cultivars over the 14 days. However, in the Tugela enzymes were repressed. In addition, it was shown for the first time that β-1,3 − 1,4-glucanase activity specific toward mixed-linked glucan was significant in the resistant cultivar over 14 days. β-1,3-glucanase, β-1,3 − 1,4-glucanase and POD displayed optimum at pH 5. β-1,3-glucanase and POD displayed temperature optimum at 40 and 50 °C, respectively. However, β-1,3 − 1,4-glucanase had temperature optimum at 25 °C. β-1,3-glucanase and POD had a thermo-stability at 37 °C followed by about 80% relative activity at 70 °C, but β-1,3 − 1,4-glucanase displayed thermostability at 25 °C and retained more than 75% at 70 °C, confirming that β-1,3 − 1,4-glucanase and β-1,3-glucanase induced in the resistant cultivars cell wall were two different enzymes. Mechanism of actions and oligosaccharide displayed that β-1,3-glucanase was highly active against β-1,3-glucan and required a triose and higher oligosaccharide to be active. Our findings demonstrated cell-wall bound POD and β-1,3-glucanase activities significantly increased in wheat after RWASA2 infestation, revealing they acted synergistically to reinforce the cell wall to deter RWASA2 feeding in resistant cultivars.

Bacteriocins are peptides or proteins produced by ribosomes that have bacteriostatic activity. Lactic acid bacteria (LAB) are the main producers of bacteriocins, and most studies have screened bacteriocin-producing lactic acid bacteria from traditional dairy products, screening lactic acid bacteria from new materials has become an important aim of bacteriocin exploration at this stage. A total of 49 LAB strains of 20 species in 6 genus were screened from a mixed sample of eight Daqu using traditional pure culture methods. And the results were then combined with high-throughput sequencing to further understand the distribution of LAB in Daqu. At the same time, the diversity of model LAB bacteriocins was explored through database analyses. Using BAGEL4 software and computer mining method, 286 gene clusters of 183 homologs from 60 different types of bacteriocins were predicted and a phylogenetic tree has been constructed to better show the distribution characteristics of bacteriocin related genes in LAB species. This study also shows that Daqu has the potential to mine bacteriocin-producing lactic acid bacteria, and provides a reference for enriching the sources of new bacteriocins.