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Discovery of the males of Lasioglossum (Eickwortia) hienae and L. (E.) alexanderi, with new distributional records for the species (Apoidea, Halictidae)
No full textWithin the diverse genus Lasioglossum, the subgenus Eickwortia as currently understood, encompasses three characteristic species from mountainous areas in Mexico and Central America. Prior to this work only Lasioglossum (Eickwortia) nycteris had descriptions for both male and female. Here we describe and illustrate the previously unknown males of L. (E.) hienae and L. (E.) alexanderi, providing new distributional data for both species, and an updated species identification key for the group
Closed nuclear fuel cycle of thermal and fast reactors with fuel self-sufficiency
No full textThe paper presents the results obtained in numerical evaluations of a possibility to reach self-sufficiency of fissile materials in the joint system of fast and thermal reactors. These studies considered the joint system consisting of thermal light-water reactors of VVER-type and fast lead-cooled reactors of BREST-type, which are operated within the frames of the closed (Th-U-Pu) fuel cycle. It was assumed that fast reactors (FR) of BREST-type used the mixed thorium-plutonium nitride fuel, while thermal reactors (TR) of VVER-type used the mixed oxide fuel of natural uranium and 233U. Uranium isotope 233U was produced in the Th-fraction of FR fuel for further introduction into the fresh composition of TR fuel, while plutonium was produced in the natural uranium fraction of TR fuel for further introduction into the fresh composition of FR fuel. The numerical studies resulted in the determination of the conditions necessary to provide fuel self-sufficiency in the joint TR-FR system. The following key findings of the research may be noted: – It is demonstrated the possibility to create the joint TR-FR system with inherent fuel self-sufficiency; – Involvement of thorium and 233U in the closed NFC of the joint TR-FR system can arrange an optimal regime for production and consumption of main FM; – Purposeful change of thermal power and introduction of natural uranium in the fuel composition of BREST-type FR made it possible to reach fuel self-sufficiency of the joint TR-FR system; – Application of radiogenic lead instead of natural lead allowed us to reduce necessary values of thermal power and content of natural uranium nitride in the fuel of BREST-type FR
Bulbillosins A - E, azaphilones from Tengochaeta bulbillosa sp. nov. (Chaetomiaceae), a root endophyte of the Chinese medicinal plant Aster tataricus
No full textAster tataricus is a plant used in Traditional Chinese Medicine. From its roots, we isolated four endophytic fungi strains. After mass spectrometry analysis and subsequent molecular networking and dereplication, one of the strain’s extracts showed a cluster of yet undescribed natural products. Additionally, the extract was found to be lethal for the nematode Caenorhabditis elegans and cytotoxic against eukaryotic cell lines. The fungal strain was characterized by morphological and molecular studies, allowing its description as a new species in the genus Tengochaeta (Chaetomiaceae), Tengochaeta bulbillosa. After cultivation and extraction of the strain, the major secondary metabolites were isolated. Structure elucidation based on nuclear magnetic resonance spectroscopy and high-resolution tandem mass spectrometry revealed these compounds to be five new azaphilones. Additionally, the localization of these azaphilones in the host plant was studied by mass spectrometry imaging of different plant tissues, revealing that they were mainly localized in the aerial parts of the plant. The main compound, bulbillosin A, was evaluated for its activity against sixty cancer cell lines, revealing a differential cytotoxicity profile
Plant species used as wood substrata for nesting by Megalopta genalis Meade-Waldo, 1916 and M. amoena Spinola, 1853 (Hymenoptera, Halictidae)
No full textHalictine bees are a group that are useful for understanding the evolutionary origins of social behavior and the evolution of nest architecture. Most species nest in the soil, but there have been several evolutionary transitions to nesting in wood. Megalopta is a nocturnal genus and represents one of the larger radiations of wood-nesting bees in the Halictinae. These bees have been observed nesting in branches and stems from trees and lianas, but it is not known to which species they belong. There is only a record of a nest in a dead trunk of Apeiba tibourbou Aubl. (Malvaceae, Tilioideae). This research aims to identify the wood plant species used as substrata by Megalopta genalis and M. amoena bees to build their nests. Fieldwork was conducted on Barro Colorado Island. Fifty-nine occupied nests were grouped in 14 morphospecies and anatomically described using transverse, longitudinal and radial sections cut with a microtome following standard histological techniques. Anatomical features of the samples belong to 11 plant species, represented by eight families of angiosperm plants and 11 genera. Considering there are anatomical features that make possible to distinguish trees and lianas like wide vessels, vessel dimorphism, abundance of axial parenchyma and others, we can determine that Megalopta bees prefer wood substrates with high proportion of soft tissues from trees or shrubs and possibly mostly liana plant species. The species most used as substrata for nesting were Uncaria tomentosa DC. (Rubiaceae), Hylenaea praecelsa (Miers) A.C.Sm. (Celastraceae) and Guettarda L. (Rubiaceae)
Extra-Mediterranean glacial refugia and range dynamics in a groundwater amphipod species, Niphargus fontanus Spence Bate, 1859, in western Central Europe
No full textThe biogeography, taxonomy and systematics of ground water organisms is still poorly understood. This is partly due to the difficult accessibility of the habitats and the expert knowledge required for identification. Nevertheless, due to the large distribution range and limited dispersal possibilities of amphipods such as the genus Niphargus, important insights can be gained into biogeographical patterns and evolutionary processes in subterranean ecosystems. Niphargus is the most species-rich genus of freshwater amphipods worldwide and holds great potential for cryptic species whose identification is important for the reconstruction of biogeographic patterns and events. Therefore, we assessed the genetic patterns of Niphargus fontanus Spence Bate, 1859 (Amphipoda: Niphargidae). We sampled the species all over its current distribution and sequenced one mitochondrial and three nuclear gene fragments. We discovered that most records from France were probably misidentifications, and that the species does not occur in central and southern France. Nevertheless, the distribution area extends from Wales to Bavaria, which could make it one of the largest distribution areas within the genus. Compared with other Niphargus, the genetic diversity and differentiation of N. fontanus is low and most likely evolved since the mid-Pleistocene Transition, but reflects a clear phylogeographic pattern with about 13 genetic lineages. These apparently stand for a number of extra-Mediterranean glacial refugia from which postglacial expansion was low to moderate. However, few cases of disjunction within these genetic lineages exist, most likely resulting from rapid expansions along river Rhine which otherwise mostly acted as a dispersal barrier
Marine-derived bioactive molecules as modulators of immune pathways: A molecular insight into pharmacological potential
No full textBackground: Marine ecosystems are a vast reservoir of bioactive compounds with immense pharmacological potential. Objectives: This review explores the molecular mechanisms of action, potential therapeutic applications, and challenges in the clinical translation of marine-derived bioactive molecules targeting immune pathways. Methods: A comprehensive literature review was conducted, analyzing studies on the immunomodulatory effects of marine-derived polysaccharides, peptides, and secondary metabolites. Result: In recent years, molecules derived from marine organisms, such as polysaccharides, peptides, and secondary metabolites, have shown promise as modulators of immune responses. These compounds interact with molecular pathways to enhance or suppress immune functions, making them valuable for treating diseases ranging from infections to autoimmune disorders and cancer. Conclusion: Marine-derived bioactive compounds exhibit significant potential as immunomodulatory agents by targeting various immune pathways. However, further research is required to optimize their pharmacological applications and address challenges in clinical translation
First record of Selaginella from Miocene amber
No full textAmong extant lycophytes, Selaginella (Selaginellaceae, spike mosses) is the most species-rich genus, with over 700 described species. The evolutionary history of this lycophyte genus dates back to the Carboniferous or even Devonian; however, amber-preserved Selaginella fossils were previously only described from mid-Cretaceous amber from Myanmar. Here, we report the first fossil from Miocene Dominican amber attributable to Selaginella based on macromorphological characters and compare the fossil morphology to extant species of the genus. Selaginella jorelisiae sp. nov. can be identified based on the presence of symmetric ovate dorsal trophophylls with scattered teeth or cilia at the margins and an aristate apex, and ventral elliptic trophophylls with an apiculate apex and rounded base, with cilia on the acroscopic proximal margin and teeth all along the rest of the margin. Fossil and subfossil Selaginella representatives from the Greater Antilles have been described based on middle Oligocene, Pleistocene, and Holocene microspores or megaspores. Selaginella jorelisiae fills a gap in the local fossil record as it represents the first evidence of Selaginellaceae from the Miocene of these islands. While the previously discovered rich cryptogamic diversity from Dominican amber is considered to represent epiphytic communities, S. jorelisiae was most likely a component of the herbaceous layer of these humid tropical forests
Two new aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) from field crops of South America
No full textDuring two seasons of field sampling in crop fields in Argentina, a total of 2,276 Aphidiinae specimens were collected using Malaise traps positioned in maize, soybean, and wheat fields. Eight known species of aphid parasitoids were identified (Aphidius platensis Brethes, 1913, A. ervi Haliday, 1834, A. rhopalosiphi de Stefani-Perez, 1902, A. uzbekistanicus Luzhetzki, 1960, A. matricariae Haliday, 1834, Diaeretiella rapae (McIntosh, 1855), Lysiphlebus testaceipes (Cresson, 1880), and Praon gallicum Starý, 1971). Additionally, two new species of aphid parasitoids were discovered, bringing the total to ten species reported from these crops in the country. Here, we describe and provide diagnoses for Aphidius brethes sp. nov. and Trioxys pampas sp. nov., which is the first record of winged species of the genus Trioxys in South America
A new species of Sedum (Crassulaceae, Saxifragineae) from Guangxi, China
No full textA new species, Sedum guangxiense sp. nov., discovered in Guangxi Province, China, is described and illustrated. Molecular phylogenetic analyses and morphological differences indicate that this species is well separated from its close relatives in Sedum, justifying its recognition as a distinct new species. Morphologically, it closely resembles Sedum tosaense and S. emarginatum in its leaf shape, inflorescence type and life form, but it can be easily distinguished in its erect stems when young, much larger leaves, narrowly triangular petals, ovate nectar scales and oblong anthers
Phloeosinus metasequoiae sp. nov. (Coleoptera, Curculionidae, Scolytinae, Phloeosinini), a new insect pest of Metasequoia glyptostroboides in China
No full textWe describe herein a previously unknown species of bark beetle, Phloeosinus metasequoiae Ning, sp. nov., which was discovered in the Xingdoushan National Nature Reserve, Hubei Province, China. This new species can be distinguished from other species in the genus Phloeosinus Chapuis, 1869 by its deeply emarginate compound eyes, coarse frontal and prothoracic surfaces, reticulate texture, and deeply V-shaped basal margin of the elytra. Phylogenetic analyses based on the cytochrome oxidase I (COI) and the large nuclear ribosomal subunit (28S) genes indicated that the new species represents an independent lineage with the closely related Phloeosinus aubei (Perris, 1885), to which it has a 95% similarity. The new species is known only from the type locality. Diagnoses, descriptions, photographs, and a distribution map are presented, along with a description of host plant damage