Expended range of Gomphonema firmum (Bacillariophyceae), once considered a Lake Baikal endemic, with notes on the identity of G. lanceolatum var. maximum

This note describes a new record of Gomphonema firmum Skvortzow, which expanded both morphological and distributional ranges of the species. This conspicuous diatom was previously unknown outside of Lake Baikal, where it inhabits deep-water areas. The newly discovered locality belongs to a small stream at a distance of 180 km west from Lake Baikal, where the species was found in a relatively high abundance that enabled to trace a size diminution series including specimens shorter than previously described. In addition, G. lanceolatum var. maximum Poretzky, a name for a diatom from Lake Teletskoe, was included in a synonymy of G. firmum that further expanded the species distribution. In the light of the presented data, the species appears to be a rare diatom with current distribution limited to a few scattered localities in southern Siberia.

Generation of Distinct Differentially Culturable Forms of Burkholderia following Starvation at Low Temperature

Bacterial pathogens exhibit physiologically distinct forms that enable their survival in an infected host, the environment and following exposure to antimicrobial agents. B. pseudomallei causes the disease melioidosis, which has a high mortality rate and is difficult to treat with antibiotics. The bacterium is endemic to several countries and detected in high abundance in the environment.

First record, new cultivated host and host plant preference of the invasive oak lace bug (Corythucha arcuata Say, 1832) (Heteroptera: Tingidae) in Transcarpathia (West Ukraine)

Oak lace bug (Corythucha arcuata) has continuously spread through Europe since its appearance in 2000, and it has become a dangerous pest of Quercus species in most countries. Despite of its high abundance in the surrounding countries it was found in West Ukraine only in 2020. During our investigation carried out in 2020 OLB was detected in all studied large forest patches of the Ukrainian part of the Carpathian Lowland. These were one of the newest distribution data from Ukraine after its appearance in the far coast of Black See near Yalta (South Ukraine). OLB most live on Q. robur and Q. petraea but in an orchard located near an infested forest patch we found infested sweet cherry (P. avium) trees, which is a new, formerly not mentioned cultivated host of the pest.

Cyp11a2 is essential for oocyte development and spermatogonial stem cell differentiation in zebrafish

Cytochrome P45011A1, encoded by Cyp11a1, converts cholesterol to pregnenolone (P5), the first and rate-limiting step in steroidogenesis. In zebrafish, cyp11a1 is maternally expressed and cyp11a2 is considered the ortholog of Cyp11a1 in mammals. A recent study has shown that depletion of cyp11a2 resulted in steroidogenic deficiencies and the mutants developed into males with feminized secondary sexual characteristics. Here, we independently generated cyp11a2 mutants in zebrafish and showed that the mutants can develop into males and females in the juvenile stage, but finally into infertile males with defective mating behavior in the adult stage. In the developing ovaries, the cyp11a2 mutation led to stage I oocyte apoptosis and final sex reversal, which could be partially rescued by treatment with P5 but not estradiol. In the developing testes, depletion of cyp11a2 resulted in dysfunction of Sertoli cells and lack of functional Leydig cells. Spermatogonial stem cells (SSCs) in the mutant testes underwent active self-renewal but no differentiation, resulting in a high abundance of SSCs in the testis, as revealed by immunofluorescence staining with Nanos2 antibody. The high abundance and differentiation competence of SSCs in the mutant testes were verified by a novel testicular cell transplantation (TCT) method developed in this study, by transplanting mutant testicular cells into germline-depleted wild-type (WT) fish. The transplanted mutant SSCs efficiently differentiated into functional spermatids in WT hosts. Overall, our study demonstrates the functional importance of cyp11a2 in early oogenesis and differentiation of SSCs.

Recent Trends in Group 9–Catalyzed C−H Borylation Reactions: Different Strategies to Control Site-, Regio-, and Stereoselectivity

Organoboron compounds continue contributing substantially to advances in organic chemistry with their increasing role as both synthetic intermediates and target compounds for medicinal chemistry. Particularly attractive methods of their synthesis are based on the direct borylation of C−H bonds of available starting materials since no additional pre-functionalization steps are required. However, due to the high abundance of C−H bonds with similar reactivity in organic molecules, synthetically useful C−H borylation protocols demand sophisticated strategies to achieve high regio- and stereoselectivity. For this purpose, selective transition-metal-based catalysts have been developed, with group 9-centered catalysts being among the most commonly utilized. Recently, a multitude of diverse strategies has been developed to push the boundaries of C−H borylation reactions with respect to their regio- and enantioselectivity. Herein, we provide an overview of approaches for the C−H borylation of arenes, alkenes, and alkanes based on group 9-centered catalysts with a focus on the recent literature. Lastly, an outlook is given to assess the future potential of the field.

Acetonitrile Adducts of Tranexamic Acid as Sensitive Ions for Quantification at Residue Levels in Human Plasma by UHPLC-MS/MS

The quantitative analysis of pharmaceuticals in biomatrices by liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is often hampered by adduct formation. The use of the molecular ion resulting from solvent adducts for quantification is uncommon, even if formed in high abundance. In this work, we propose the use of a protonated acetonitrile adduct for the quantitative analysis of tranexamic acid (TXA) by LC-MS/MS. The high abundance of the protonated acetonitrile adduct [M + ACN + H]+ was found to be independent of source-dependent parameters and mobile phase composition. The results obtained for TXA analysis in clinical samples were comparable for both [M + ACN + H]+ and [M + H]+, and no statistically significant differences were observed. The relative stability and structure of the [M + ACN + H]+ ions were also studied by analyzing probable structures from an energetic point of view and by quantum chemical calculations. These findings, and the studied fragmentation pathways, allowed the definition of an acetimidium structure as the best ion to describe the observed acetonitrile protonated adduct of TXA.

The Diversity Patterns of Rare to Abundant Microbial Eukaryotes Across a Broad Range of Salinities in a Solar Saltern

Solar salterns are excellent artificial systems for examining species diversity and succession along salinity gradients. Here, the eukaryotic community in surface water of a Korean solar saltern (30 to 380 practical salinity units) was investigated from April 2019 to October 2020 using Illumina sequencing targeting the V4 and V9 regions of 18S rDNA. A total of 926 operational taxonomic units (OTUs) and 1,999 OTUs were obtained with the V4 and V9 regions, respectively. Notably, most of the OTUs were microbial eukaryotes, and the high-abundance groups (> 5% relative abundance (RA), Alveolata, Stramenopila, Archaeplastida, and Opisthokonta) usually accounted for > 90% of the total cumulative read counts and > 80% of all OTUs. Moreover, the high-abundance Alveolata (larger forms) and Stramenopila (smaller forms) groups displayed a significant inverse relationship, probably due to predator–prey interactions. Most of the low-abundance (0.1–5% RA) and rare (< 0.1% RA) groups remained small portion during the field surveys. Taxonomic novelty (at < 90% sequence identity) was high in the Amoebozoa, Cryptista, Haptista, Rhizaria, and Stramenopila groups (69.8% of all novel OTUs), suggesting the presence of a large number of hidden species in hypersaline environments. Remarkably, the high-abundance groups had little overlap with the other groups, implying the weakness of rare-to-prevalent community dynamics. The low-abundance Discoba group alone temporarily became the high-abundance group, suggesting that it is an opportunistic group. Overall, the composition and diversity of the eukaryotic community in hypersaline environments may be persistently stabilized, despite diverse disturbance events.

The density and distribution of Pacific Oyster (Crassostrea gigas) in Krueng Cut, Aceh Besar

Crassostrea gigas is a Pacific oyster that has the largest size among the other oysters. This oyster is most often found because of its ability to adapt to a variety of environments. Krueng Cut is an estuary area that gets a lot of nutrient input from sea water because it is directly adjacent to the ocean. This condition makes this area has a high abundance of oysters with high fishing and antropogenic activities as well. The purpose of this study was to determine the density and distribution of the oyster population from 3 representative stations along the estuary area of Krueng Cut. The method used in this study is random sampling using a quadratic transect. The results show that the highest density is indicated by station 3 with 55.67 ind/m2 and the lowest density is indicated by station 1 is 40.33 ind/m2. These results indicate that the activities of residents, the entry of contaminants from antropogenic affect the density of oysters. The distribution of oysters from the three stations showed similarities, namely they tended to grouping. The aquatic environment at the three research stations still supports the growth of oysters. This study confirms that there has been a decline in the population, which is characterized by a decrease in the number of catches and a smaller size of oysters.

The composition of haypiles of Turuchan pika (Preliminary analysis)

The species composition and abundance of plants in the Turuchan pika habitat and in its haypiles were studied in the talus surrounded by taiga on the Primorsky ridge. With the Ivlev’s Electivity Index, it was found that the pika was selective in collecting food: Veratrum nigrum and Urtica dioica, being relatively rare in the habitat, were highly preferred and abundant in the haypiles. The bulk of the haypiles also consisted of 4 species (Rubus matsumuranus, Sambucus sibirica, Populus tremula, Spiraea media) with a high abundance in the habitat and collected proportionally with their abundance. Many plant species being abundant in the habitat were not stored by pikas.