Morphological and molecular evidence confirms a new species, Riccia subcrinita YouL.Xiang & R.L.Zhu) and Riccia junghuhniana Nees & Lindenb. (Ricciaceae, Marchantiophyta) new to China

Riccia is the largest genus of complex thalloid liverworts (Marchantiopsida) with over 250 species currently accepted. Our recent investigation of Chinese liverworts found two interesting Riccia species, R. junghuhniana and Riccia subcrinita sp. nov. Riccia junghuhniana is currently known from Australia and Indonesia, while Riccia subcrinita is known only from China. Riccia subcrinita is similar to R. crinita, but differs in having smaller spores (56–71 µm in diameter), and spore distal surface and proximal surface alveoli without thick borders. The sequences of rbcL, rps4, and trnL-F, detailed descriptions, and illustrations of the Chinese specimens are provided. The range extension of R. junghuhniana suggests that more taxa of Riccia may have a wider distribution. The discovery of R. junghuhniana and the new species also suggests that a more intensive survey of Riccia diversity in China is necessary.

Paphiopedilum charlesworthii var. lannaense, a new slipper orchid from Northern Thailand identified by morphological and AFLP analyses

A new endemic slipper orchid in the family Orchidaceae from Northern Thailand was described according to morphological and molecular analyses. Morphological information specifies the new slipper orchid Paphiopedilum charlesworthii var. lannaense to be similar to Paphiopedilum charlesworthii (Rolfe) Pfitzer 1895, with the exception of its staminode being obovate-obcordate with yellow color, glittery and rough surface. Molecular analysis by AFLP technique indicates that Paphiopedilum charlesworthii var. lannaense can be included as a member of section Paphiopedilum and is closely related to Paphiopedilum coccineum Perner, H. & Herrmann, R. (2000) (syn. Paphiopedilum barbigerum var. coccineum), from which it differs morphologically by dorsal sepal and petal characters. The morphological and molecular evidence supported that Paphiopedilum charlesworthii var. lannaense is a new slipper orchid in the genus Paphiopedilum (Cypripedioideae, Orchidaceae).

Three new Xylaria species (Xylariaceae, Xylariales) on fallen leaves from Hainan Tropical Rainforest National Park

Three new species of Xylaria on fallen leaves in Hainan Province of China are described and illustrated, based on morphological and molecular evidence. Xylaria hedyosmicola is found on fallen leaves of Hedyosmum orientale and featured by thread-like stromata with a long sterile filiform apex. Phylogenetically, X. hedyosmicola is closely related to an undescribed Xylaria sp. from Hawaii Island, USA and morphologically similar to X. vagans. Xylaria lindericola is found on fallen leaves of Lindera robusta and characterised by its subglobose stromata and a long filiform stipe. It is phylogenetically closely related to X. sicula f. major. Xylaria polysporicola is found on fallen leaves of Polyspora hainanensis, it is distinguished by upright or prostrate stromata and ascospores sometimes with a slimy sheath or non-cellular appendages. Xylaria polysporicola is phylogenetically closely related to X. amphithele and X. ficicola. An identification key to the ten species on fallen leaves in China is given.

West Nile virus transmission potential in Portugal

It is unclear whether West Nile virus (WNV) circulates endemically in Portugal. Despite the country’s adequate climate for transmission, Portugal has only reported four human WNV infections so far. We performed a review of WNV-related data (1966–2020), explored mosquito (2016–2019) and land type distributions (1992–2019), and used climate data (1981–2019) to estimate WNV transmission suitability in Portugal. Serological and molecular evidence of WNV circulation from animals and vectors was largely restricted to the south. Land type and climate-driven transmission suitability distributions, but not the distribution of WNV-capable vectors, were compatible with the North-South divide present in serological and molecular evidence of WNV circulation. Our study offers a comprehensive, data-informed perspective and review on the past epidemiology, surveillance and climate-driven transmission suitability of WNV in Portugal, highlighting the south as a subregion of importance. Given the recent WNV outbreaks across Europe, our results support a timely change towards local, active surveillance.

The Morphological Characteristics and Phylogenetic Analyses Revealed an Additional Taxon in Heteroradulum (Auriculariales)

Auriculariales is diverse, embracing a number of corticioid, poroid, and hydnoid genera. The present study covers a new wood-inhabiting fungal species of Heteroradulum niveum sp. nov that is proposed on the basis of a combination of morphological features and molecular evidence. The species is characterized by the resupinate basidiomata, a monomitic hyphal system with generative hyphae with clamp connections; tubular cystidia; two- to four-celled basidia; and allantoid, colorless, thin-walled, smooth, IKI–, CB–, basidiospores (6.5–13.5 × 2.7–5.5 µm). Sequences of ITS and nLSU rRNA gene regions of the specimens were generated, and phylogenetic analyses were carried out with methods of maximum parsimony, maximum likelihood, and Bayesian inference. These phylogenetic analyses inferred from ITS+nLSU indicated that H. niveum is nested in Heteroradulum within Auriculariales. Further study within Heteroradulum on the basis of ITS+nLSU dataset revealed that it formed a monophyletic lineage with a strong support (100% BS, 100% BP, 1.00 BPP) and then grouped with H. yunnanensis.

A Complexed Crystal Structure of a Single-Stranded DNA-Binding Protein with Quercetin and the Structural Basis of Flavonol Inhibition Specificity

Single-stranded DNA (ssDNA)-binding protein (SSB) plays a crucial role in DNA replication, repair, and recombination as well as replication fork restarts. SSB is essential for cell survival and, thus, is an attractive target for potential antipathogen chemotherapy. Whether naturally occurring products can inhibit SSB remains unknown. In this study, the effect of the flavonols myricetin, quercetin, kaempferol, and galangin on the inhibition of Pseudomonas aeruginosa SSB (PaSSB) was investigated. Furthermore, SSB was identified as a novel quercetin-binding protein. Through an electrophoretic mobility shift analysis, myricetin could inhibit the ssDNA binding activity of PaSSB with an IC50 of 2.8 ± 0.4 μM. The effect of quercetin, kaempferol, and galangin was insignificant. To elucidate the flavonol inhibition specificity, the crystal structure of PaSSB complexed with the non-inhibitor quercetin was solved using the molecular replacement method at a resolution of 2.3 Å (PDB entry 7VUM) and compared with a structure with the inhibitor myricetin (PDB entry 5YUN). Although myricetin and quercetin bound PaSSB at a similar site, their binding poses were different. Compared with myricetin, the aromatic ring of quercetin shifted by a distance of 4.9 Å and an angle of 31o for hydrogen bonding to the side chain of Asn108 in PaSSB. In addition, myricetin occupied and interacted with the ssDNA binding sites Lys7 and Glu80 in PaSSB whereas quercetin did not. This result might explain why myricetin could, but quercetin could not, strongly inhibit PaSSB. This molecular evidence reveals the flavonol inhibition specificity and also extends the interactomes of the natural anticancer products myricetin and quercetin to include the OB-fold protein SSB.

Divergence of X-linked trans regulatory proteins and the misexpression of gene targets in sterile Drosophila pseudoobscura hybrids

Background The genetic basis of hybrid incompatibilities is characterized by pervasive cases of gene interactions. Sex chromosomes play a major role in speciation and X-linked hybrid male sterility (HMS) genes have been identified. Interestingly, some of these genes code for proteins with DNA binding domains, suggesting a capability to act as trans-regulatory elements and disturb the expression of a large number of gene targets. To understand how interactions between trans- and cis-regulatory elements contribute to speciation, we aimed to map putative X-linked trans-regulatory elements and to identify gene targets with disrupted gene expression in sterile hybrids between the subspecies Drosophila pseudoobscura pseudoobscura and D. p. bogotana. Results We find six putative trans-regulatory proteins within previously mapped X chromosome HMS loci with sequence changes that differentiate the two subspecies. Among them, the previously characterized HMS gene Overdrive (Ovd) had the largest number of amino acid changes between subspecies, with some substitutions localized within the protein’s DNA binding domain. Using an introgression approach, we detected transcriptional responses associated with a sterility/fertility Ovd allele swap. We found a network of 52 targets of Ovd and identified cis-regulatory effects among target genes with disrupted expression in sterile hybrids. However, a combined analysis of polymorphism and divergence in non-coding sequences immediately upstream of target genes found no evidence of changes in candidate regulatory proximal cis-elements. Finally, peptidases were over-represented among target genes. Conclusions We provide evidence of divergence between subspecies within the DNA binding domain of the HMS protein Ovd and identify trans effects on the expression of 52 gene targets. Our results identify a network of trans-cis interactions with possible effects on HMS. This network provides molecular evidence of gene × gene incompatibilities as contributors to hybrid dysfunction.

Intestinal Protists in Captive Non-human Primates and Their Handlers in Six European Zoological Gardens. Molecular Evidence of Zoonotic Transmission

We assessed the occurrence, genetic diversity, and zoonotic potential of four protozoan (Cryptosporidium spp., Entamoeba histolytica, Entamoeba dispar, Giardia duodenalis), one stramenopile (Blastocystis sp.), one microsporidia (Enterocytozoon bieneusi), and two ciliate (Balantioides coli, Troglodytella abrassarti) intestinal parasite or commensal protist species in captive non-human primates (NHP) and their zookeepers from six European zoological gardens in France (n = 1), Germany (n = 1), and Spain (n = 4). Faecal samples from NHP (n = 454) belonging to 63 species within 35 genera and humans (n = 70) were collected at two sampling periods in each participating institution between October 2018-August 2021. Detection and species identification was accomplished by PCR and Sanger sequencing of the ssu rRNA and/or ITS genes. Sub-genotyping analyses using specific markers were conducted on isolates positive for G. duodenalis (gdh, bg, tpi) and Cryptosporidium spp. (gp60). Overall, 41.0% (186/454) and 30.0% (21/70) of the faecal samples of NHP and human origin tested positive for at least one intestinal protist species, respectively. In NHP, Blastocystis sp. was the most prevalent protist species found (20.3%), followed by G. duodenalis (18.1%), E. dispar (7.9%), B. coli and T. abrassarti (1.5% each), and Cryptosporidium spp. and E. bieneusi (0.9% each). Occurrence rates varied largely among NHP host species, sampling periods, and zoological institutions. The predominant protist species found in humans was Blastocystis sp. (25.7%), followed by Cryptosporidium spp. (2.9%), E. dispar (1.4%), and G. duodenalis (1.4%). Sequencing of PCR-positive amplicons in human and/or NHP confirmed the presence of Cryptosporidium in six isolates (C. hominis: 66.7%, C. parvum: 33.3%), G. duodenalis in 18 isolates (assemblage A: 16.7%, assemblage B: 83.3%), Blastocystis in 110 isolates (ST1:38.2%, ST2:11.8%, ST3: 18.2%, ST4: 9.1%, ST5: 17.3%, ST8: 2.7%, ST13: 0.9%), and E. bieneusi in four isolates (CM18: 75.0%, Type IV: 25.0%). Zoonotic transmission events involving Blastocystis ST1–ST4 were identified in four zoological institutions. Zoonotic transmission of C. hominis was highly suspected, but not fully demonstrated, in one of them. Monitoring of intestinal protist species might be useful for assessing health status of captive NHP and their zookeepers, and to identify transmission pathways of faecal-orally transmitted pathogens.