Search results for "Phylogenetic"

Maternally‐transferred thyroid hormones and life‐history variation in birds

2022

1. In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early-phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in maternal THs within the physiological range can influence offspring phenotype. 2. Given the essential functions of maternal THs in development and metabolism, THs may be a mediator of life-history variation across species. 3. We tested the hypothesis that differences in life histories are associated with differences in maternal TH transfer across species…

Early evolutionary colocalization of the nuclear ribosomal 5S and 45S gene families in seed plants: evidence from the living fossil gymnosperm Ginkgo…

2012

In seed plants, the colocalization of the 5S loci within the intergenic spacer (IGS) of the nuclear 45S tandem units is restricted to the phylogenetically derived Asteraceae family. However, fluorescent in situ hybridization (FISH) colocalization of both multigene families has also been observed in other unrelated seed plant lineages. Previous work has identified colocalization of 45S and 5S loci in Ginkgo biloba using FISH, but these observations have not been confirmed recently by sequencing a 1.8 kb IGS. In this work, we report the presence of the 45S–5S linkage in G. biloba, suggesting that in seed plants the molecular events leading to the restructuring of the ribosomal loci are much o…

Community Analysis of Culturable Sapwood Endophytes from Apulian Olive Varieties with Different Susceptibility to Xylella fastidiosa

2021

Endophytes are symptomless fungal and/or bacterial microorganisms found in almost all living plant species. The symbiotic association with their host plants by colonizing the internal tissues has endowed them as a valuable tool to suppress diseases, stimulate growth, and promote stress resistance. In this context, the study of culturable endophytes residing the sapwood of Apulian olives might be a promising control strategy for xylem colonizing pathogens as Xylella fastidiosa. To date, olive sapwood cultivable endophytes are still under exploration; therefore, this work pursues a study of cultivable endophytes occurrence variation in the sapwood of different olive varieties under the effect…

Root and crown rot of olive caused by Phytophthora spp

2011

Molecular evolution of aphids and their primary (Buchnera sp.) and secondary endosymbionts: Implications for the role of symbiosis in insect evolution

2001

Aphids maintain an obligate, endosymbiotic association with Buchnera sp., a bacterium closely related to Escherichia coli. Bacteria are housed in specialized cells of organ-like structures called bacteriomes in the hemocoel of the aphid and are maternally transmitted. Phylogenetic studies have shown that the association had a single origin, dated about 200-250 million years ago, and that host and endosymbiont lineages have evolved in parallel since then. However, the pattern of deepest branching within the aphid family remains unsolved, which thereby hampers an appraisal of, for example, the role played by horizontal gene transfer in the early evolution of Buchnera. The main role of Buchner…

The genome sequence of Blochmannia floridanus: Comparative analysis of reduced genomes

2003

Bacterial symbioses are widespread among insects, probably being one of the key factors of their evolutionary success. We present the complete genome sequence of Blochmannia floridanus , the primary endosymbiont of carpenter ants. Although these ants feed on a complex diet, this symbiosis very likely has a nutritional basis: Blochmannia is able to supply nitrogen and sulfur compounds to the host while it takes advantage of the host metabolic machinery. Remarkably, these bacteria lack all known genes involved in replication initiation ( dna A, pri A, and rec A). The phylogenetic analysis of a set of conserved protein-coding genes shows that Bl. floridanus is phylogenetically related to Buch…

Index Seminum: annis 2018-2019 collectorum quae

2018

Latvijas Universitātes Botāniskā dārza starptautiskajai sēklu apmaiņai ievākto sēklu saraksts 2018.-2019. gadam. Tajā ir 617 taksoni, tajā skaitā 44, kam sēklas ir ievāktas savvaļā.

Diversification in evolutionary arenas - assessment and synthesis

2019

Abstract Understanding how and why rates of evolutionary diversification vary is a central issue in evolutionary biology and ecology. The concept of adaptive radiation has attracted much interest, but is metaphorical and verbal in nature, making it difficult to quantitatively compare different evolutionary lineages or geographic regions. In addition, the causes of evolutionary stasis are relatively neglected. Here we review the central concepts in the evolutionary diversification literature and bring these together by proposing a general framework for estimating rates of diversification and quantifying their underlying dynamics, which can be applied across clades and regions and across spat…

Malus Mill. drawings

1980

Profesora Voldemāra Langenfelda (1923–2007) sagatavots mācību materiāls par ābeļu ģinti (Mallus Mill.). Zīmējusi viņa sieva Astrīda Langenfelde. Komplektā trūkst 1. kartītes. Materiāls glabājās Latvijas Universitātes Muzeja Botānikas un mikoloģijas kolekcijā.