Related Congeners Research Articles

Synthesis and Antitumor Activity of Some New N1-(8-fluoro-4-oxoquinolin-5-yl)amidrazones.

Hydrazonoyl chloride, accessible from the respective 5-amino-8-fluoro- 4-oxoquinoline-3-carboxylate, undergoes a reaction with sec-cyclic amines to generate N1-(1- ethyl-8-fluoro-4-oxoquinolin-5-yl)amidrazone carboxylates. A novel set of N1-(1-ethyl-8-fluoro-4-oxoquinolin-5-yl)amidrazone carboxylates (7a-h) incorporating N-piperazines or related congeners was synthesized via interaction of the hydrazonoyl chloride (6), accessible from the respective 5-amino-8-fluoro-4-oxoquinoline-3-carboxylate, with the appropriate sec-cyclic amine. These new compounds were characterized by 1HNMR, 13C-NMR, and HRMS spectral data and screened for their anticancer activities. This study aimed at the synthesis of novel N1-( 4-oxoquinolin-5-yl)amidrazone carboxylate derivatives and investigated their potential as anticancer agents. The reaction of hydrazonoyl chloride with the appropriate sec-cyclic amine was applied to synthesize a novel set of N1-(1-ethyl-8-fluoro-4-oxoquinolin-5- yl)amidrazone carboxylates that incorporate N piperazines. A direct reaction of piperazines and related sec-cyclic amines with N-(4-oxoquinolin-5- yl)nitrile imine (1,3-dipole) was carried out for 8-10 h. The 1,3-dipole, generated in situ from its hydrazonoyl chloride precursor in the presence of trimethylamine, is suitable for the facile synthesis of N1-(1-ethyl-8-fluoro-4-oxoquinolin-5- yl)amidrazone carboxylates. This study led to the successful synthesis of novel N1-(8-fluoro-4-oxoquinolin-5- yl)amidrazones. All the examined compounds showed moderate activity with reasonable IC50 values in the micromolar range compared to Doxorubicin.

On the taxonomy of the genus Lethe Hübner (Lepidoptera, Papilionoidea, Nymphalidae, Satyrinae) with description of a new species

New information on the genus Lethe is presented. A new species of the Lethe tristigmata-complex, L. sunglam sp. nov. is described from Mt. Fansipan, northern Vietnam. The individual variation of Lethe jianqingi Lang, 2016 is discussed and its female is reported for the first time and compared with the related taxa. Lethe lyncus de Nicéville, 1897 is found to be a good species different from the related congeners, and L. wui H. Huang, 1999 was synonymized with it (syn. nov.). Adults and male genitalia of the aforementioned taxa and related ones as well are illustrated.

Genetic Diversity and Structure of Physaria on the Kaibab Plateau: Implications for Conservation.

Assessing patterns of genetic diversity within and among closely related congeners is important for evaluating the conservation status of rare plant taxa. We used nuclear microsatellite genotyping to examine the genetic relatedness among three Physaria taxa on the Kaibab Plateau in northern Arizona. Over 100 species of Physaria are recognized, and are widely distributed in Western North America. On the Kaibab Plateau several taxa occur, including Physaria arizonica and two subspecies of P. kingii, P. kingii subsp. latifolia and P. kingii subsp. kaibabensis. The latter subspecies, the Kaibab bladderpod, is rare and endemic to the Kaibab Plateau and is a potential candidate to be listed under the Endangered Species Act. Morphological characters, primarily flower color, have been used to distinguish P. kingii subsp. kaibabensis from other subspecies. Here we aim to assess its genetic diversity and differentiation as compared to congeners on and around the Kaibab Plateau. We genotyped DNA obtained from leaf samples from 463 individuals collected from 26 sites representing the three putative taxa (12 P. kingii subsp. kaibabensis, 8 P. kingii subsp. latifolia, and 6 P. arizonica). Our results showed that all samples initially identified as P. kingii subsp. latifolia and P. kingii subsp. kaibabensis on the Kaibab Plateau form a single genetic cluster that is well-differentiated from P. kingii subsp. latifolia sampled from sites off the plateau or P. arizonica on or off the plateau. For P. kingii on the plateau, our findings do not support the previous subspecies designations based on morphological characters. While additional studies of P. kingii will further resolve taxonomic uncertainties within this species, our findings indicate that the Kaibab Plateau population is genetically diverse and genetically distinct, and federal protection is justified in light of the threats faced on the Kaibab Plateau and its limited range.

A Strongly Ambiphilic Ferrocene-Based Cyclic (Alkyl)(amino)carbene - Specific Decomposition to an Enamine by a 1,2-Phenyl Shift.

The recently described crystalline cyclic (alkyl)(amino)carbene with a 1,1'-ferrocenylene (fc) backbone fc(CPh2-C-NMes) (A, Mes=mesityl) is highly reactive due to its particularly pronounced ambiphilicity and is thermally not stable in solution due to an intramolecular insertion of the divalent carbon atom into a methyl C-H bond of the Mes substituent. The closely related congener fc(CPh2-C-N-p-C6H4-tBu) (1) cannot undergo such an insertion reaction. Nevertheless, 1 is too short-lived for isolation due to a rapid 1,2-shift of a phenyl group, furnishing the isomeric cyclic enamine fc[C(Ph)=C(Ph)-N-p-C6H4-tBu] (1') in a specific decomposition process unprecedented for CAACs. Trapping of 1 was possible with carbon monoxide, elemental selenium and with [CuBr(SMe2)], respectively affording the aminoketene 1=C=O, the selenoamide 1=Se and the homoleptic CuI complex [Cu(1)2][CuBr2]. 1 is an even stronger ambiphile than A according to NMR spectroscopic data. Similar to A, 1 does not react with H2, because the experimentally observed intramolecular process is kinetically more favourable according to DFT results.

Genome-Wide Data Uncover Cryptic Diversity With Multiple Reticulation Events in the Balkan-Anatolian Cardamine (Brassicaceae) Species Complex.

Plant species diversity may be considerably underestimated, especially in evolutionarily complex genera and in diversity hotspots that have enabled long-term species persistence and diversification, such as the Balkan Peninsula. Here, we address the topic of underexplored plant diversity and underlying evolutionary and biogeographic processes by investigating the hygrophytic mountain species complex of Cardamine acris s.l. distributed in the Balkans (three subspecies within C. acris) and northwestern Anatolia (C. anatolica). We performed a series of phylogenetic and phylogeographic analyses based on restriction-site associated DNA sequencing (RADseq) and target enrichment (Hyb-Seq) data in combination with habitat suitability modelling. We found C. anatolica as a clade nested within the Balkan C. acris, probably resulting from a founder event, and uncovered three allopatric cryptic lineages within C. acris subsp. acris, allowing us to recognise a total of six entities in this complex. We observed the deepest genetic split within C. acris subsp. acris in the western Balkans, which was at odds with taxonomy and showed no distribution gap. We inferred vicariance as the most likely process for population divergence in the Balkans, accompanied by gene flow between the recognised entities, which was consistent with the modelled habitat suitability dynamics. Furthermore, we discovered several polyploid populations in C. acris, representing both pure intra- and inter-lineage hybrid polyploids, but detected only minor traces of hybridization with related congeners. Overall, our results illustrate that diverse evolutionary processes may influence the history of mountain plant species in the Balkan Peninsula, including vicariance, reticulation, polyploidization and cryptic diversification.

A Small-molecule Antagonist Radiotracer for Positron Emission Tomography Imaging of the Mu Opioid Receptor.

The opioid crisis is a catastrophic health emergency catalyzed by the misuse of opioids that target and activate the mu opioid receptor. Traditional radioligands used to study the mu opioid receptor are often tightly regulated owing to their abuse and respiratory depression potential. In the present study, we sought to design and characterize a library of 24 non-agonist ligands for the mu opioid receptor. Ligands were evaluated for the binding affinity, intrinsic activity, and predicted blood-brain barrier permeability. Several ligands demonstrated single-digit nM binding affinity for the mu opioid receptor while also demonstrating selectivity over the delta and kappa opioid receptors. The antagonist behavior of 1A and 3A at the mu opioid receptor indicate that these ligands would likely not induce opioid-dependent respiratory depression. Therefore, these ligands can enable a safer means to interrogate the endogenous opioid system. Based on binding affinity, selectivity, and potential off-target binding, [ 11 C] 1A was prepared via metallophotoredox of the aryl-bromide functional group to [ 11 C]methyl iodide. The nascent radiotracer demonstrated brain uptake in a rhesus macaque model and accumulation in the caudate and putamen. Naloxone was able to reduce [ 11 C] 1A binding, though the interactions were not as pronounced as naloxone's ability to displace [ 11 C]carfentanil. These results suggest that GSK1521498 and related congeners are amenable to radioligand design and can offer a safer way to query opioid neurobiology.

Human bare and clothing-covered skin exposure to chlorinated paraffins for the general populations: Exposure pattern differential and significance of indirect dermal exposure via clothing-to-skin transport

To investigate human exposure to short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) through dermal and oral intake via hand-to-mouth contact, wipes from the face, forearm, hand, and foot of 30 volunteers were sampled. The concentration of ∑SCCPs and ∑MCCPs ranged from 0.66 to 119 and 0.71 to 565 µg/m2, respectively. Hands exhibited significantly higher ∑CPs concentrations than other skin areas, indicating that direct contact with indoor surfaces contributed considerable CP levels on this bare skin area. Gender differences in CP levels were observed in wipes from all locations, except for the hands, possibly because of the significant variability in residuals on the hands. A significant positive relationship was found between CP levels on the hands and faces, and the CP ratios of the hands/faces were related to log KOA. Bare skin showed more significant variations in CP partitioning among related congeners and between genders than skin covered by clothing, as elucidated by the linear analysis of RSD and log KOA. Although concentrations on clothing-covered areas were relatively lower than on bare skin, the median estimated dermal absorption doses of ∑SCCPs and ∑MCCPs (152 and 737 ng/kg bw/day, respectively) for the entire body were approximately 1–2 orders of magnitude higher than those for oral ingestion (1.62 and 7.94 ng/kg bw/day, respectively), emphasizing indirect dermal uptake as a significant exposure pathway for humans.

Highly Functionalized Spirobisnaphthalenes from Roussoella sp. KT4147.

Highly functionalized spirobisnaphthalenes, preussomerins N (1) and O (2), and simpler compounds, such as 2,3-α-epoxypalmarumycin CP18 (3), 3α-hydroxy-CJ-12,372 (4), and 16 known structurally related congeners, were isolated from a culture broth of Roussoella sp. KT4147. Structural analysis revealed that 1 was a dimer of preussomerin G (6), connected by a nitrogen atom, and 2 was a derivative of 6 with a macommelin substructure. Preussomerin N (1) was considered to be biosynthetically derived via the Michael-type 1,4-addition of ammonia to 6, followed by another Michael addition to another molecule of 6. Contrarily, 2 was suggested to be derived through an endo-Diels-Alder cycloaddition between a diene derived from the (E)-enol form of macommelinal via an ene-reaction and dienophile 6. Compounds 1 and 2 exhibited potent cytotoxicity against COLO-201 human colorectal cancer cells.

Asymmetric total synthesis of polycyclic xanthenes and discovery of a WalK activator active against MRSA

The development of new antibiotics continues to pose challenges, particularly considering the growing threat of multidrug-resistant Staphylococcus aureus. Structurally diverse natural products provide a promising source of antibiotics. Herein, we outline a concise approach for the collective asymmetric total synthesis of polycyclic xanthene myrtucommulone D and five related congeners. The strategy involves rapid assembly of the challenging benzopyrano[2,3-a]xanthene core, highly diastereoselective establishment of three contiguous stereocenters through a retro-hemiketalization/double Michael cascade reaction, and a Mitsunobu-mediated chiral resolution approach with high optical purity and broad substrate scope. Quantum mechanical calculations provide insight into stereoselective construction mechanism of the three contiguous stereocenters. Additionally, this work leads to the discovery of an antibacterial agent against both drug-sensitive and drug-resistant S. aureus. This compound operates through a unique mechanism that promotes bacterial autolysis by activating the two-component sensory histidine kinase WalK. Our research holds potential for future antibacterial drug development.

On a small collection of Maeridae Krapp-Schickel, 2008 (Crustacea: Amphipoda) from Gujarat, India

The present study was based on amphipod specimens collected from the coastal areas of Gujarat state, India. From the collection, four species belonging to the family Maeridae Krapp-Schickel, 2008 were identified. Two species, Ceradomaera plumosa Ledoyer, 1973 and Ceradocus (Denticeradocus) alama Myers & Nithyanandan, 2016 are reported for the first time from Gujarat state and India, respectively. Two more species, Maera gujaratensis sp. nov. and Quadrimaera okha sp. nov. are described as new species. Maera gujaratensis sp. nov. can be differentiated from its closely related congener M. hirondellei Chevreux, 1900 on the basis of shape of male gnathopod 1 coxa and number of setae present on the telson. Quadrimaera okha sp. nov. can be differentiated from its closely related congeners Q. brownorum Hughes, 2015 and Q. caliban (Ruffo, Krapp & Gable, 2000) by the non-lobate anterodistal corner of gnathopod 2 basis, by the shape of the propodus of the male gnathopod 2, and in having a comparatively smaller uropod 3 peduncle to rami ratio.

Kallopterolides A-I, a New Subclass of seco-Diterpenes Isolated from the Southwestern Caribbean Sea Plume Antillogorgia kallos.

Kallopterolides A-I (1-9), a family of nine diterpenoids possessing either a cleaved pseudopterane or a severed cembrane skeleton, along with several known compounds were isolated from the Caribbean Sea plume Antillogorgia kallos. The structures and relative configurations of 1-9 were characterized by analysis of HR-MS, IR, UV, and NMR spectroscopic data in addition to computational methods and side-by-side comparisons with published NMR data of related congeners. An investigation was conducted as to the potential of the kallopterolides as plausible in vitro anti-inflammatory, antiprotozoal, and antituberculosis agents.

A new species of Neofilchneria (Plecoptera: Perlodidae) from China, with supplementary information on N. wanglanga Chen, 2019

A new species of the perlodid genus Neofilchneria Zwick, 1973, N. cheni sp. nov. from Hubei Province of central China, is described, illustrated, and compared with related congeners. Neofilchneria wanglanga Chen, 2019 is newly recorded from Yunnan Province. The hitherto unknown aedeagus of N. wanglanga is described for the first time.

Updated range map of an endangered salamander and congeneric competitor reveals different niche preferences.

Estimating distributions for cryptic and highly range-restricted species induces unique challenges for species distribution modeling. In particular, bioclimatic covariates that are typically used to model species ranges at regional and continental scales may not show strong variation at scales of 100s and 10s of meters. This limits both the likelihood and usefulness of correlated occurrence to data typically used in distribution models. Here, we present analyses of species distributions, at 100 × 100 m resolution, for a highly range restricted salamander species (Shenandoah salamander, Plethodon shenandoah) and a closely related congener (red-backed salamander, Plethodon cinereus). We combined data across multiple survey types, account for seasonal variation in availability of our target species, and control for repeated surveys at locations- all typical challenges in range-scale monitoring datasets. We fit distribution models using generalized additive models that account for spatial covariates as well as unexplained spatial variation and spatial uncertainty. Our model accommodates different survey protocols using offsets and incorporates temporal variation in detection and availability resulting from survey-specific variation in temperature and precipitation. Our spatial random effect was crucial in identifying small-scale differences in the occurrence of each species and provides cell-specific estimates of uncertainty in the density of salamanders across the range. Counts of both species were seen to increase in the 3 days following a precipitation event. However, P. cinereus were observed even in extremely wet conditions, while surface activity of P. shenandoah was associated with a more narrow range. Our results demonstrate how a flexible analytical approach improves estimates of both distribution and uncertainty, and identify key abiotic relationships, even at small spatial scales and when scales of empirical data are mismatched. While our approach is especially valuable for species with small ranges, controlling for spatial autocorrelation, estimating spatial uncertainty, and incorporating survey-specific information in estimates can improve the reliability of distribution models in general.

On a small collection of amphipods (Crustacea, Amphipoda) from Chilika Lake with the description of three new species and a new genus

The current study was conducted on the basis of a small collection of amphipods made from Chilika Lake that contained 4 species. Three were described as new species, including one new genus: Parhyale kalinga sp. nov., Chilikorchesta chiltoni gen. nov. sp. nov. and Grandidierella rabindranathi sp. nov., while a fourth one was a previously reported species: Quadrivisio bengalensis Stebbing, 1907. Parhyale kalinga sp. nov. can be differentiated from its closely related congeners Parhyale basrensis Salman, 1986 and Parhyale darvishi Momtazi & Maghsoudlou, 2016 by having male gnathopod 2 propoduswith 2 robust setae at the base of the palm and 2 small setae slightly behind the palm and dactylus much smaller than palm. Chilikorchestia chiltoni gen. nov. sp. nov. can be differentiated from the closely related genus Morinoia Lowry & Myers, 2019 by its incrassate male antenna 2 and untapered telson. Grandidierella rabindranathi sp. nov. can be differentiated from its closely related congeners G. mahafalensis Coutière, 1904 and Grandidierella nioensis Myers, Sreepada & Sanaye, 2019 by having male gnathopod 2 carpus oval shaped with both margins convex.

Access to 3‐Azetidines via Halogenation of Titanacyclobutanes

AbstractAzetidines are valuable nitrogenous heterocycles. Herein, we disclose a strategy for the modular assembly of 3‐azetidines and related spirocyclic congeners featuring all‐carbon quaternary centers. This approach leverages titanacyclobutanes generated from ketones or alkenes. Halogenation of these organotitanium species gives rise to functionalized alkyl dihalides that can be subsequently captured by amines to afford azetidine building blocks. This strategy facilitated the synthesis of a small molecule anti‐tuberculosis drug. It also enabled access to carbon‐13 isotopologs of diazaspiro[3.3]heptane fragments that are challenging to prepare by any other means.

New species of Culicoides, description of female of Culicoides pseudocrescentis Tavares & Luna Dias and new record of Culicoides castillae Fox from Southeastern Brazil (Diptera: Ceratopogonidae)

A new species of Culicoides, C. andradinensis Felippe-Bauer & Santarém is described and illustrated based on female specimens from the municipality of Andradina, São Paulo state, Brazil. The new species is placed in the limai species group and compared with their related congeners. The description of females of Culicoides pseudocrescentis Tavares & Luna Dias based on specimens from Brazilian states of Espírito Santo and São Paulo is given. Culicoides castillae Fox is first recorded from Brazil. All studied specimens are deposited in the Ceratopogonidae Collection of Fundação Oswaldo Cruz, Brazil (Fiocruz/CCER).

Description of a new species of the genus Cultellus Schumacher, 1817 (Bivalvia, Pharidae) from the South China Sea, based on integrative taxonomy

The present study describes a new species within the genus Cultellus Schumacher, 1817 collected from the South China Sea. An integrative taxonomic approach incorporating morphological comparisons, geometric morphometrics and genetic analyses was used to identify and differentiate the new species. Cultellus exilissp. nov. is distinguished from its congeners by its slender, fragile and translucent valves, curved posteroventral margins and relatively large protractor scars. The geometric morphometric analyses, based on outlines data, indicated that samples of Cultellus exilissp. nov. clustered together and were distinctly separated from other species. Multiple species delimitation results, based on the mitochondrial COI gene, support the separation of Cultellus exilissp. nov. from its related congeners. Phylogenetic analyses of a nuclear (28S rRNA) and two mitochondrial (COI, 16S rRNA) genes using Maximum Likelihood and Bayesian Inference methods revealed that the species belongs to the genus Cultellus. The superfamily Solenoidea Lamarck, 1809, which includes the families Solenidae Lamarck, 1809 and Pharidae H. Adams & A. Adams, 1856, exhibits closer affinity to the family Hiatellidae Gray, 1824 than to Solecurtidae d’Orbigny, 1846. Furthermore, we found that the genus Siliqua was clustered alongside the genera Ensiculus and Phaxas as a sister clade, which contradicts the current systematics of the subfamily within the family Pharidae. This work highlights the utility of integrative taxonomy for species identification, recognition and phylogenetic investigation.

A new species of Stygobromus Cope, 1872 (Amphipoda, Crangonyctidae) from a hypotelminorheic seepage spring in Washington, D.C., USA

We describe a new species of subterranean amphipod (Amphipoda: Crangonyctidae) in the genus Stygobromus from a hypotelminorheic seepage spring at Shepherd Parkway, part of National Capital East Parks, Washington, D.C., USA, part of the National Park System, using both morphological and genetic approaches. The Anacostia Groundwater Amphipod, S. anacostensissp. nov. is a member of the S. tenuis species group but differs from related congeners based on body size, serrate blade-like edge of both palms of gnathopods 1 and 2, presence of rastellate setae on the posterodistal margin of the carpus of gnathopod 2, and aspects of the second antennae, mandibular palp, pereopods 5–7, uropods 1 and 2, and telson. Moreover, S. anacostensissp. nov. is genetically distinct from S. tenuis in the Washington D.C. metropolitan area. The description of S. anacostensissp. nov. increases the number of described Stygobromus species to eight in the Washington D.C. area and highlights the need for continued biodiversity studies, even in regions that have received considerable attention.

Two new Dryopteris taxa originated from distantly related congeners in China

AbstractSince the inception of genetic investigations into the origin of Dryopteris species belonging to D. subg. Erythrovariae in East Asia, around 20 taxa with hybrid ancestry have been identified. Among these species, some have arisen from distant interspecific hybridization events. In this study, we describe and illustrate two newly discovered hybrids from China: Dryopteris parabissetiana sp. nov., a triploid species, and D. ×tiantangzhaiensis nothosp. nov., a diploid hybrid within Dryopteridaceae. Morphologically, D. parabissetiana exhibits similarities to D. bissetiana but can be distinguished by its ovate scales, while D. ×tiantangzhaiensis clearly displays intermediate characteristics between D. gymnophylla and D. tsoongii. Phylogenetic analyses indicate that D. tsoongii serves as their maternal parent, while D. bissetiana and D. gymnophylla are their paternal parents, respectively. Furthermore, we propose a section‐level classification for such hybrids of mixed parental sections.

Limnophyes knispelae sp. n. and L. sartorii sp. n., two new crenophilous species from the Swiss Alps (Chironomidae, Orthocladiinae)

Limnophyes knispelae sp. n and L. sartorii sp. n. are diagnosed and described based on material collected in the high Alpine valley of the Rhône river and the cirque of Macun in the Swiss National Park (alt. 1800-2616 m a.s.l.). The first new species is described only as male adult, while the second as male adult and pupal exuviae. Main distinguishing characters found in the male adult of L. knispelae sp. n. L. sartorii sp. n. are: clypeus shield-like shaped; humeral pit typically circular with 3-4 or 9 lanceolate setae; virga strong spine-like; preepisternals vary from 4-6 to 4-8. The pupal exuviae of L. sartorii sp. n. is characterized by having frontal apotome domed; thoracic horn reduced to nose-like tubercle; posterior area of tergites II-VI with 1-7 rows of minute hooks; segment VIII with 5 lateral setae; inner posterior margin of anal lobe straight. A combination of the latter relevant morphological characters has allowed us to consider each of the two new species as a local biogeographic representative of the Swiss Alps. Currently, the genus Limnophyes Eaton, 1875 is represented in Switzerland by 15 species. Consequently, the description of L. knispelae sp. n and L. sartorii sp. n. increases the total number in the genus to 17 known valid species from this country. Discussions and a differential diagnosis on the two new species are given, in which some morphological affinities and distinguishing characters with other related congeners are detailed and highlighted. Comments on the ecology and geographical distribution of the new species are also provided.