A new species and a replacement name in Cynanchum (Apocynaceae, Asclepiadeae) from China.

Cynanchumpingtaoi S.Jin Zeng, G.D.Tang & Miao Liao, sp. nov. (Apocynaceae) from Yunnan Province, China, is described and illustrated based on morphological and molecular evidence. Its deeply cordate to reniform leaves and campanulate, large flowers show that it is a member of former Raphistemma Wall., which has been included in Cynanchum L.. It is different from all former Raphistemma species by the broadly ovate corolla lobes, purple-red corolla and connivent corona tip slightly exceeding the corolla throat. Meanwhile, Cynanchumlonghushanense G.D.Tang & Miao Liao, nom. nov. is proposed as replacement name for Raphistemmabrevipedunculatum Y.Wan, which was considered a synonym of Cynanchumhooperianum (Blume) Liede & Khanum but is here reinstated as a distinct species because of significant morphological differences.

Spatial distribution pattern and correlation of dominant populations in the shrub layer of Fengshui forest in Leizhou Peninsula, China.

To elucidate the spatial patterns of understory species in fragmented forests adjacent to human settlements, we examined the spatial distribution and intraspecific correlations of three dominant species Mallotus philippensis, Dasymashalon trichophorum, and Psychotria rubra by employing point pattern analysis, which were the top three in terms of importance value in the shrub layer of Fengshui forest in Leizhou Peninsula, Guangdong. The results showed that all the three species were mainly aggregated at the scale of 0-25 m, especially for young trees. The degree of aggregation gradually diminished with increasing age class. The spatial distribution patterns of three species were predominantly influenced by habitat heterogeneity, negative density dependence, and dispersal limitation. They showed positive association among different age classes, especially between young trees and middle age trees and between young trees and adult trees. Therefore, in the ecological restoration process of Leizhou Peninsula, M. philippensis, D. trichophorum, and P. rubra should be planted in clusters at a small scale within the range of 0-25 m, with the degree of clusters depending on plant morphology. For larger scales, a dispersed cultivation approach was advocated.

Lysimachiadanxiashanensis, a new species of Primulaceae from Guangdong, China.

Lysimachiadanxiashanensis, a new Primulaceae species, endemic to the Danxia landscape in Guangdong Province, China, is described and illustrated. This new species is morphologically similar to L.pseudohenryi, L.phyllocephala, L.congestiflora and L.kwangtungensis, but it differs from the similar species by its purplish-red plants, petiole without wings, calyx with orange glandular and the corolla margin serrated on upper half with orange-red glandular punctates. This new species belongs to Lysimachiasubgen.Lysimachiasect.Nummularia. Phylogenetic analysis confirmed that L.danxiashanensis is a distinct clade, based on the combined data of ITS and rbcL sequences. The conservation status of the new species was evaluated as Endangered (EN) according to IUCN Red List Categories and Criteria.

Fertilization- and Irrigation-Modified Bacterial Community Composition and Stimulated Enzyme Activity of Eucalyptus Plantations Soil.

Irrigation and fertilization are essential management practices for increasing forest productivity. They also impact the soil ecosystem and the microbial population. In order to examine the soil bacterial community composition and structure in response to irrigation and fertilization in a Eucalyptus plantations, a total of 20 soil samples collected from Eucalyptus plantations were analyzed using high-throughput sequencing. Experimental treatments consisting of control (CK, no irrigation or fertilization), fertilization only (F), irrigation only (W), and irrigation and fertilization (WF). The results showed a positive correlation between soil enzyme activities (urease, cellulase, and chitinase) and fertilization treatments. These enzyme activities were also significantly correlated with the diversity of soil bacterial communities in Eucalyptus plantations.. Bacteria diversity was considerably increased under irrigation and fertilization (W, F, and WF) treatments when compared with the CK treatment. Additionally, the soil bacterial richness was increased in the Eucalyptus plantations soil under irrigation (W and WF) treatments. The Acidobacteria (38.92-47.9%), Proteobacteria (20.50-28.30%), and Chloroflexi (13.88-15.55%) were the predominant phyla found in the Eucalyptus plantations soil. Specifically, compared to the CK treatment, the relative abundance of Proteobacteria was considerably higher under the W, F, and WF treatments, while the relative abundance of Acidobacteria was considerably lower. The contents of total phosphorus, accessible potassium, and organic carbon in the soil were all positively associated with fertilization and irrigation treatments. Under the WF treatment, the abundance of bacteria associated with nitrogen and carbon metabolisms, enzyme activity, and soil nutrient contents showed an increase, indicating the positive impact of irrigation and fertilization on Eucalyptus plantations production. Collectively, these findings provide the scientific and managerial bases for improving the productivity of Eucalyptus plantations.

Diploid and tetraploid genomes of Acorus and the evolution of monocots.

Monocots are a major taxon within flowering plants, have unique morphological traits, and show an extraordinary diversity in lifestyle. To improve our understanding of monocot origin and evolution, we generate chromosome-level reference genomes of the diploid Acorus gramineus and the tetraploid Ac. calamus, the only two accepted species from the family Acoraceae, which form a sister lineage to all other monocots. Comparing the genomes of Ac. gramineus and Ac. calamus, we suggest that Ac. gramineus is not a potential diploid progenitor of Ac. calamus, and Ac. calamus is an allotetraploid with two subgenomes A, and B, presenting asymmetric evolution and B subgenome dominance. Both the diploid genome of Ac. gramineus and the subgenomes A and B of Ac. calamus show clear evidence of whole-genome duplication (WGD), but Acoraceae does not seem to share an older WGD that is shared by most other monocots. We reconstruct an ancestral monocot karyotype and gene toolkit, and discuss scenarios that explain the complex history of the Acorus genome. Our analyses show that the ancestors of monocots exhibit mosaic genomic features, likely important for that appeared in early monocot evolution, providing fundamental insights into the origin, evolution, and diversification of monocots.

Complete plastid genome sequence of Oberonioides microtatantha (Schltr.) Szlach. (Orchidaceae), an endemic herb in China.

The species Oberonioides microtatantha, belonging to the family Orchidaceae, is a small lithophytic herb endemic in south China with significant conservation values. The complete plastid genome sequence of O. microtatantha reported here is 144,989 bp in length, with a large single copy (LSC) region of 83,920 bp, a small single copy (SSC) region of 13,063 bp, and a pair of inverted repeat (IRa and IRb) regions of 24,003 bp each. The plastome consists of 95 genes, including 72 protein-coding genes, 4 ribosomal RNA genes, and 19 transfer RNA genes. The overall GC content is 36.81%. Phylogenetic analysis placed Oberonioides closet to the genus Liparis in Orchidaceae.

Complete plastome sequence of Hoya carnosa (L. f.) R. Br. (Apocynaceae).

Hoya is a remarkable genus with high horticultural ornamental value. In this study, we report and characterize the complete plastid genome sequence of Hoya carnosa. The complete chloroplast genome was 176,340 bp in length, which includes a pair of inverted repeat regions (IRs) of 41,381 bp separated by a large single copy region (LSC) 91,281 bp and a small single copy region (SSC) 2,297 bp. Interestingly, IRs expanded into SSC, with the result that most of the genes in SSC were duplicated. This chloroplast genome contained 110 genes, including 76 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. The complete plastome sequence of H. carnosa will provide some useful information for future phylogenetic study of Hoya and its horticultural application.

Decoding the evolution and transmissions of the novel pneumonia coronavirus (SARS-CoV-2 / HCoV-19) using whole genomic data.

The outbreak of COVID-19 started in mid-December 2019 in Wuhan, China. Up to 29 February 2020, SARS-CoV-2 (HCoV-19 / 2019-nCoV) had infected more than 85 000 people in the world. In this study, we used 93 complete genomes of SARS-CoV-2 from the GISAID EpiFlu TM database to investigate the evolution and human-to-human transmissions of SARS-CoV-2 in the first two months of the outbreak. We constructed haplotypes of the SARS-CoV-2 genomes, performed phylogenomic analyses and estimated the potential population size changes of the virus. The date of population expansion was calculated based on the expansion parameter tau ( τ) using the formula t= τ/2 u. A total of 120 substitution sites with 119 codons, including 79 non-synonymous and 40 synonymous substitutions, were found in eight coding-regions in the SARS-CoV-2 genomes. Forty non-synonymous substitutions are potentially associated with virus adaptation. No combinations were detected. The 58 haplotypes (31 found in samples from China and 31 from outside China) were identified in 93 viral genomes under study and could be classified into five groups. By applying the reported bat coronavirus genome (bat-RaTG13-CoV) as the outgroup, we found that haplotypes H13 and H38 might be considered as ancestral haplotypes, and later H1 was derived from the intermediate haplotype H3. The population size of the SARS-CoV-2 was estimated to have undergone a recent expansion on 06 January 2020, and an early expansion on 08 December 2019. Furthermore, phyloepidemiologic approaches have recovered specific directions of human-to-human transmissions and the potential sources for international infected cases.

The complete chloroplast genome of the highly poisonous plant Cerbera manghas L. (Apocynaceae).

The complete chloroplast genome of Cerber amanghas L., a species of the tribe Plumerieae of the family Apocynaceae, is determined for the first time here. The chloroplast genome is 154,428 bp long, containing a large single-copy region (LSC) of 85,138 bp and a small single-copy region (SSC) of 17,390 bp, which are separated by a pair of 25,950 bp long inverted repeat regions (IRs). It encodes a total of 115 genes, including 81 unique protein-coding genes, 30 unique tRNA genes, and 4 unique rRNA genes.Phylogenetic analysis revealed that C.manghas is a member of the paraphyletic tribe Plumerieae of Apocynaceae and is closely related to Thevetia peruviana.

Oreocharis tetrapterus (Gesneriaceae), a new species from East Guangxi, China.

A new species, Oreocharis tetrapterus F.Wen, B.Pan & T.V.Do (Gesneriaceae) from Gupo Mountain area, Hezhou city, Guangxi Zhuangzu Autonomous Region, China, is described and illustrated. The new species has a zygomorphic tetramerous corolla with two adaxial and two abaxial lobes and two fertile stamens in the posterior position, making this a unique combination of floral characteristics in the expanded Oreocharis.

Eyeglasses-based tear biosensing system: Non-invasive detection of alcohol, vitamins and glucose.

We report on a wearable tear bioelectronic platform, integrating a microfluidic electrochemical detector into an eyeglasses nose-bridge pad, for non-invasive monitoring of key tear biomarkers. The alcohol-oxidase (AOx) biosensing fluidic system allowed real-time tear collection and direct alcohol measurements in stimulated tears, leading to the first wearable platform for tear alcohol monitoring. Placed outside the eye region this fully wearable tear-sensing platform addresses drawbacks of sensor systems involving direct contact with the eye as the contact lenses platform. Integrating the wireless electronic circuitry into the eyeglasses frame thus yielded a fully portable, convenient-to-use fashionable sensing device. The tear alcohol sensing concept was demonstrated for monitoring of alcohol intake in human subjects over multiple drinking courses, displaying good correlation to parallel BAC measurements. We also demonstrate for the first time the ability to monitor tear glucose outside the eye and the utility of wearable devices for monitoring vitamin nutrients in connection to enzymatic flow detector and rapid voltammetric scanning, respectively. These developments pave the way to build an effective eyeglasses system capable of chemical tear analysis.

Simultaneous Monitoring of Sweat and Interstitial Fluid Using a Single Wearable Biosensor Platform.

The development of wearable biosensors for continuous noninvasive monitoring of target biomarkers is limited to assays of a single sampled biofluid. An example of simultaneous noninvasive sampling and analysis of two different biofluids using a single wearable epidermal platform is demonstrated here. The concept is successfully realized through sweat stimulation (via transdermal pilocarpine delivery) at an anode, alongside extraction of interstitial fluid (ISF) at a cathode. The system thus allows on-demand, controlled sampling of the two epidermal biofluids at the same time, at two physically separate locations (on the same flexible platform) containing different electrochemical biosensors for monitoring the corresponding biomarkers. Such a dual biofluid sampling and analysis concept is implemented using a cost-effective screen-printing technique with body-compliant temporary tattoo materials and conformal wireless readout circuits to enable real-time measurement of biomarkers in the sampled epidermal biofluids. The performance of the developed wearable device is demonstrated by measuring sweat-alcohol and ISF-glucose in human subjects consuming food and alcoholic drinks. The different compositions of sweat and ISF with good correlations of their chemical constituents to their blood levels make the developed platform extremely attractive for enhancing the power and scope of next-generation noninvasive epidermal biosensing systems.

Variation of soil bacterial communities along a chronosequence of Eucalyptus plantation.

Eucalyptus is harvested for wood and fiber production in many tropical and sub-tropical habitats globally. Plantation has been controversial because of its influence on the surrounding environment, however, the influence of massive Eucalyptus planting on soil microbial communities is unclear. Here we applied high-throughput sequencing of the 16S rRNA gene to assess the microbial community composition and diversity of planting chronosequences, involving two, five and ten years of Eucalyptus plantation, comparing to that of secondary-forest in South China. We found that significant changes in the composition of soil bacteria occurred when the forests were converted from secondary-forest to Eucalyptus. The bacterial community structure was clearly distinct from control and five year samples after Eucalyptus was grown for 2 and 10 years, highlighting the influence of this plantation on local soil microbial communities. These groupings indicated a cycle of impact (2 and 10 year plantations) and low impact (5-year plantations) in this chronosequence of Eucalyptus plantation. Community patterns were underpinned by shifts in soil properties such as pH and phosphorus concentration. Concurrently, key soil taxonomic groups such as Actinobacteria showed abundance shifts, increasing in impacted plantations and decreasing in low impacted samples. Shifts in taxonomy were reflected in a shift in metabolic potential, including pathways for nutrient cycles such as carbon fixation, which changed in abundance over time following Eucalyptus plantation. Combined these results confirm that Eucalyptus plantation can change the community structure and diversity of soil microorganisms with strong implications for land-management and maintaining the health of these ecosystems.

Epidermal Microfluidic Electrochemical Detection System: Enhanced Sweat Sampling and Metabolite Detection.

Despite tremendous recent efforts, noninvasive sweat monitoring is still far from delivering its early analytical promise. Here, we describe a flexible epidermal microfluidic detection platform fabricated through hybridization of lithographic and screen-printed technologies, for efficient and fast sweat sampling and continuous, real-time electrochemical monitoring of glucose and lactate levels. This soft, skin-mounted device judiciously merges lab-on-a-chip and electrochemical detection technologies, integrated with a miniaturized flexible electronic board for real-time wireless data transmission to a mobile device. Modeling of the device design and sweat flow conditions allowed optimization of the sampling process and the microchannel layout for achieving attractive fluid dynamics and rapid filling of the detection reservoir (within 8 min from starting exercise). The wearable microdevice thus enabled efficient natural sweat pumping to the electrochemical detection chamber containing the enzyme-modified electrode transducers. The fabricated device can be easily mounted on the epidermis without hindrance to the wearer and displays resiliency against continuous mechanical deformation expected from such epidermal wear. Amperometric biosensing of lactate and glucose from the rapidly generated sweat, using the corresponding immobilized oxidase enzymes, was wirelessly monitored during cycling activity of different healthy subjects. This ability to monitor sweat glucose levels introduces new possibilities for effective diabetes management, while similar lactate monitoring paves the way for new wearable fitness applications. The new epidermal microfluidic electrochemical detection strategy represents an attractive alternative to recently reported colorimetric sweat-monitoring methods, and hence holds considerable promise for practical fitness or health monitoring applications.

Wearable Ring-Based Sensing Platform for Detecting Chemical Threats.

This work describes a wireless wearable ring-based multiplexed chemical sensor platform for rapid electrochemical monitoring of explosive and nerve-agent threats in vapor and liquid phases. The ring-based sensor system consists of two parts: a set of printed electrochemical sensors and a miniaturized electronic interface, based on a battery-powered stamp-size potentiostat, for signal processing and wireless transmission of data. A wide range of electrochemical capabilities have thus been fully integrated into a 3D printed compact ring structure, toward performing fast square-wave voltammetry and chronoamperometric analyses, along with interchangeable screen-printed sensing electrodes for the rapid detection of different chemical threats. High analytical performance is demonstrated despite the remarkable miniaturization and integration of the ring system. The attractive capabilities of the wearable sensor ring system have been demonstrated for sensitive and rapid voltammetric and amperometric monitoring of nitroaromatic and peroxide explosives, respectively, along with amperometric biosensing of organophosphate (OP) nerve agents. Such ability of the miniaturized wearable sensor ring platform to simultaneously detect multiple chemical threats in both liquid and vapor phases and alert the wearer of such hazards offers considerable promise for meeting the demands of diverse defense and security scenarios.

Size distribution of stranded small plastic debris on the coast of Guangdong, South China.

Beach environments are known to be conducive to fragmentation of plastic debris, and highly fragmented plastic particles can interact with smaller organisms. Even through stranded plastic debris may not interact directly with marine organisms, backwash processes may transport this debris back to coastal waters, where it may affect a wide range of marine life at different trophic levels. This study analysed the size distribution of stranded plastic debris (<10 mm) collected from eight coastal beaches in Guangdong Province, China. Polystyrene (PS) foams and fragments smaller than 7 mm were increasingly abundant in the smaller size classes, whereas resin pellets remained in their production sizes (∼3 mm). Microplastics (<5 mm) accounted for over 98% of the total plastic debris by abundance and 71% by weight, indicating that the plastic debris on these coastal beaches was highly fragmented and the majority of the plastic masses belonged to the microplastic size range. The observed size distributions of PS foams and fragments are believed to result from continued fragmentation. Previous studies found that the residence time of beached debris was less than one year on average, and no sign of plastic accumulation with depth in beach sediment was observed. Therefore, coastal beaches may represent a reservoir of highly fragmented and degraded microplastics that may be mobilised and returned to the sea during storm events. Further research on the dynamics and longevity of microplastics on beaches will help reveal the mass balance of microplastics on the shoreline and determine whether shorelines are sinks or sources of microplastics.

Adding perches for cross-pollination ensures the reproduction of a self-incompatible orchid.

BACKGROUND: Outcrossing is known to carry genetic advantages in comparison with inbreeding. In many cases, flowering plants develop a self-incompatibility mechanism, along with a floral component adaptation mechanism, to avoid self-pollination and to promote outbreeding. Orchids commonly have a lip in their flower that functions as the a visiting plate for insect pollinators. Aside from the lip, however, many species (including Coelogyne rigida) have sheaths around the axis of inflorescence. The function of these sheaths remains unknown, and has long been a puzzle to researchers. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the function of these sheaths in relation to the lip and the pollinators, as well as their role in the modes of pollination and reproduction of Coelogyne rigida in 30 flowering populations of orchids in the limestone area of Southeast Yunnan, China. We found that self-incompatible C. rigida developed specialized bird perches around the basal axis of inflorescence to attract sunbirds and to complement their behavioral tendency to change foraging locations frequently. This self-incompatibility mechanism operates separately from the floral component adaptation mechanism. This mechanism thus prevents bees from repeatedly visiting the floral lip of the same plant which, in turn, results in autogamy. In this way, instead of preventing autogamy, C. rigida responds to these negative effects through a highly efficient cross-pollination method that successfully transfers pollen to different plants. CONCLUSIONS: The proposed method ensures reproductive success, while offsetting the infertile self-pollination by insects, thereby reducing mating costs and addressing the lack of cross-pollination. The adaptation provides a novel and striking example of structural adaptation that promotes cross-pollination in angiosperms.

Pollination: self-fertilization strategy in an orchid.

Mating in flowering plants normally relies on animals, wind, gravity or secretion to convey pollen grains from the male (anther) to the female (stigma) organ. Here we describe a new type of self-pollination mechanism in the tree-living orchid Holcoglossum amesianum, in which the bisexual flower turns its anther against gravity through 360 degrees in order to insert pollen into its own stigma cavity - without the aid of any pollinating agent or medium. This mode of self-pollination, which occurs under windless, drought conditions when insects are scarce, adds to the variety of mechanisms that have evolved in angiosperms to ensure their reproductive success.