Biologia最新文献

Plants rhizosphere and bacterial communities’ association offer great advantages for its adaptation to adverse conditions in desert ecosystems. In the Sonoran Desert, Mexico, there is low diversity of species due to the significant incidence of high salinity, drought and extreme temperatures. However, Parkinsonia aculeata L. is an endemic species adapted to these adverse environmental conditions. Here, we aimed to isolate and molecularly characterize bacterial isolates associated with P. aculeata rhizosphere grown in saline soils (BL site) and drought (RT site). A total of thirty-three bacteria isolates from the P. aculeata rhizosphere were identified by 16S rDNA sequencing finding members of the genera: Bacillus, Enterobacter, Priestia, Sinomonas, Micrococcus, Kocuria, Staphylococcus, Streptomyces, Arthrobacter and Peribacillus. Priestia followed by Bacillus and Staphylococcus genus showed the major abundance percentages in both sites. The isolated strains were previously reported to exhibit plant beneficial traits, promote plant growth preserve the soil, provide an opportunity for the development of environmentally friendly alternatives for agriculture and to be used as experimental models to study drought/salt mitigation.

The whitefly Bemisia tabaci (Gennadius) has coevolved with intracellular endosymbiotic bacteria that help supplement their nutrient-poor diets with essential amino acids and carotenoids; however the type of host species and the agricultural practices can influence the composition of the endosymbiotic bacterial community. In this study, the main goal was to explore the diversity of endosymbiont communities in whitefly populations growing in peppers (Capsicum chinense Jacq. under greenhouse and Capsicum annuum L. backyard) exposed to chemical insecticides (treatment MB1) and non-exposed (treatment MB2). The whiteflies were identified through phylogenetic analysis of the mitochondrial Cytochrome Oxidase I gene sequences. Bacterial endosymbionts were characterized by high-throughput sequencing of the V3 region of the 16S rRNA gene, which amplifies a fragment of around 180 bp. Sequence analysis yielded in MB1 eight Phylum, nine classes, 30 orders, 35 families, 64 genera, and 20 species, while in MB2 it was obtained eight Phylum, 11 classes, 26 orders, 37 families, 61 genera, and 18 species. The most abundant phylum in the two samples analyzed was Proteobacteria followed by Chlamydiae and Bacteroidetes. The phyla that presented the greatest taxonomic diversity of bacteria at the genus level in both samples were Proteobacteria, Actinobacteria and Firmicutes. According to the evaluated alpha diversity indices, low richness and diversity were obtained in the two samples, but when comparing the two samples, MB2 showed the greatest richness and diversity with 1,698 with the Shannon index.. The results obtained are a first approximation to describe the impact of insecticides used on peppers on the diversity and richness of whitefly endosymbiotic bacteria.

Gold nanoparticles have numerous applications, many of which are notable in industries. The biosynthesis of gold nanoparticles offers an easy, effective, green, and eco-friendly approach. In organisms capable of synthesizing nanoparticles, enzymes and proteins are responsible for the structural and functional modifications that lead to their formation. These include ABC transporter, peptide-binding proteins, which are dependent on abiotic parameters. This study uses the purified ABC transporter, peptide-binding protein transformed from Thermus scotoductus SA-01 and expressed in mesophilic Escherichia coli BL21 and thermophilic Thermus thermophilus HB27 hosts for the biosynthesis of gold nanoparticles at different concentrations, temperatures, and pH values. Gold nanoparticle formation was evaluated with a range of gold (III) concentrations (0–10 mM), incubated at temperatures ranging from 30–85 ºC and pH levels from 3.6–9.0. Transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and UV–Vis absorption spectroscopy were used to characterise the formation of nanoparticles. In all of the protein reactions, UV–Vis absorbance peaks at approximately 520–560 nm confirmed the formation of gold nanoparticles. Optimum nanoparticle synthesis was observed at pH values ranging from 5.5 to 9.0, gold (III) solution (HAuCl₄) concentrations from 0.5–2.0 mM, and a maximum temperature of 65ºC in the mesophilic host and 85ºC in the thermophilic host, indicating the significance of temperature in both hosts for the expression and bioactivity of the purified ABC transporter protein. However, the biogenic formation of gold nanoparticles using E. coli and T. thermophilus hosts was not monodispersed, suggesting a necessity for further development of the procedure.

This study addresses the complex taxonomy and distribution of the genus Portulaca L. (Portulacaceae) within the Balkans, focusing on the often-debated species composition and distribution patterns in the P. oleracea aggregate. Our research aims to resolve this ambiguity by addressing two key questions: 1) Which Portulaca taxa are present in the Balkans, and 2) What is the current distribution of these taxa here? To achieve this, we conducted literature reviews, seed collection, species identification using micromorphological characteristics, and distribution analysis. Our findings reveal the presence of four distinct species in the Balkans: P. oleracea agg., P. grandiflora, P. pilosa and P. umbraticola. Additionally, within the P. oleracea complex, twelve microspecies have been identified, primarily differentiated based on seed micromorphology. Besides, five species (P. daninii, P. granulato-stellulata, P. rausii, P. sardoa, and P. trituberculata) have been documented in Montenegro, and one species (P. nitida) – in Slovenia for the first time. This study provides a valuable contribution to the botanical knowledge of the Balkan Peninsula, offering the recommendations for future studies of the P. oleracea complex for the solution of the taxonomic puzzle in this aggregate.

Stick insects (Phasmatodea) in general are remarkable for presenting striking camouflage-related adaptations. Even so, a considerable number of species are colorful and present other defense mechanisms, such as the New World lineage Pseudophasmatidae. Within this family, Urucumania currently comprises two described species occurring in Brazil, Bolivia and Paraguay, both of which have small scale-like wings. Urucumania is currently placed in Anisomorphini. However, two similar species under Pseudophasma present remarkable similarities with Urucumania species. These two species, Pseudophasma nigrovittatum and Pseudophasma dentata, are the only Pseudophasma presenting scale-like wings. Both inhabit Brazil, are known from a single sex and present a generally similar coloration pattern contrasting to that of Urucumania. Aiming to resolve whether these and other similar specimens represent distinct species, and if they belong to Urucumania rather than to Pseudophasma, we conducted a careful analysis of the external morphology of both sexes, eggs and the male genitalia. We transfer both scale-like winged Pseudophasma to Urucumania, redescribing them based on both sexes showing that the two described species are in fact distinct, and furthermore present 13 new species of Urucumania from Brazil and Bolivia: Urucumania pirulai sp. n., U. varellai sp. n., U. guadanuccii sp. n., U. atilai sp. n., U. intervalica sp. n., U. brasil sp. n., U. tapirape sp. n., U. rasocatarinensis sp. n., U. dilatata sp. n., U. sertaneja sp. n., U. albopunctata sp. n., U. oriomadeirensis sp. n. and U. candanga sp. n.

To fill the gap of eriophyoid mites in Iran, a field survey was carried out in northwest Iran (Aras dam lake, West Azerbaijan Province), in summer 2022. As a result, a new vagrant Aceria species (Acari: Eriophyoidea: Eriophyidae) associated with Artemisia scoparia Waldst. & Kit. (Asteraceae) was discovered. The new species is illustrated and described herein as Aceria artemiparia sp. n. No apparent damage was observed on the host. This is the second report of an eriophyoid mite species associated to A. scoparia host plant. Aceria artemiparia sp. n. is unique among 24 Aceria spp. associated with Artemisia species by having a smooth prodorsal shield and 8–rayed empodium. Furthermore, we provided a checklist and morphological key of eriophyoid mites associated with Artemisia spp. of the world.

The niche partitioning hypothesis predicts differential use of resources among morphs depending on resource dynamics and morph frequencies. Additionally, morphs might select microhabitats favorable for the regulation of body temperature through behavioral mechanisms. Intra- and intersexual social interactions among morphs can also affect patterns of niche partitioning. Here, we evaluated whether body size, thermal traits (body and environmental temperatures, and behavioral thermoregulation), microhabitat use, and perch height differ among male and female throat color morphs of the lizard Sceloporus grammicus in four different habitat types. Color morphs of both sexes differed in body size, thermal traits, and perch height but not microhabitat use. Lizards of grassland and xeric scrubland were larger, and had greater values of thermal traits but exhibited lower perch height than lizards of mountain cloud forest and pine-oak forest. We found clear evidence of thermal niche partitioning and partial space niche partitioning among color morphs of both sexes of S. grammicus in central Mexico. These results improve our knowledge of the ecology of color polymorphic vertebrate species and show that color morphs of each sex have specific trait combinations to facilitate the use of thermal resources.

The generation of reactive oxygen/nitrogen species under either natural or stressful conditions activates antioxidant systems to balance the redox status in plant cells. The effect of seed priming with low concentrations of H₂O₂ and/or arginine (Arg) was examined on redox status of salinity-stressed Vicia faba in the present study. Salinity stress produced H₂O₂ and caused oxidative damage to photosynthetic pigments and membrane lipids represented by reduction in chlorophyll contents and carbohydrate production, and high accumulation of malondialdehyde, denoted as oxidative distress. Under saline conditions, Arg and/or H₂O₂ priming increased the activity of antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase), non-enzymatic antioxidants (phenols, flavonoids, anthocyanins and carotenoids), proline and total antioxidant activity (based on the FRAP method) followed by a reduction in the malondialdehyde content and an increase in the chlorophylls and water soluble carbohydrates contents. Altogether, the seed priming with H₂O₂ and Arg could constitute a ‘priming memory’ in seeds of V. faba, which recruited upon a subsequent salinity stress-exposure and induced stress-tolerance of primed beans trough invoking antioxidant systems.

Streptococcus agalactiae stands out as a significant bacterial pathogen, causing substantial economic losses in the aquaculture sector. Given the challenges posed by multidrug resistance, this study explores the potential of phage therapy as an alternative to antibiotics in biocontrol strategies. The focus is on evaluating the multidrug resistance profile of S. agalactiae isolated from a tilapia aquaculture farm, with particular attention to the strain KSA/01, which exhibits resistance to seven structurally different classes of antibiotics and a notable MAR index of around 0.6. In response to this challenge, the study successfully identifies and isolates the specific and lytic phage SAP-13 targeting the multidrug-resistant strain KSA/01. Transmission electron microscopy reveals that SAP-13 shares morphological characteristics with the Siphoviridae family. In a one-step growth curve, the phage demonstrates a substantial burst size of approximately 610 PFU/cell over a short burst period and the phage exhibited stability across various physicochemical parameters such as temperature, pH, and salinity. In vitro lytic ability of SAP-13 at different multiplicity of infection underscores its potential to effectively eliminate S. agalactiae, particularly at an MOI of 0.01. Consequently, these findings suggest that phage SAP-13 exhibits high infectivity against S. agalactiae, presenting a promising avenue for addressing multidrug-resistant strains in aquaculture.