Living with marginal coral communities: Diversity and host-specificity in coral-associated barnacles in the northern coral distribution limit of the East China Sea

<div><p>Corals and their associated fauna are extremely diverse in tropical waters and form major reefs. In the high-latitude temperate zone, corals living near their distribution limit are considered marginal communities because they are particularly extremely sensitive to environmental and climatic changes. In this study, we examined the diversity and host usage of coral-associated barnacles on Jeju Island, Korea, the northern coral distribution limit in the East China Sea. In this study, only three coral-associated barnacles—from two genera in two subfamilies—were collected. The Pyrgomatinid barnacles <i>Cantellius arcuatus</i> and <i>Cantellius</i> cf. <i>euspinulosum</i> were found only on the corals <i>Montipora millepora</i> and <i>Alveopora japonica</i>, respectively. The Megatrematinid barnacle <i>Pyrgomina oulastreae</i>, relatively a generalist, was found on <i>Psammocora</i> spp. (both <i>profundacella</i> and <i>albopicta</i>) and <i>Oulastrea crispata</i> corals. The host usage of these three barnacles does not overlap. DNA barcode sequences of the <i>C</i>. <i>arcuatus</i> specimens collected in the present study matched those collected in Kochi in Japan, Taiwan, Malaysia and Papua New Guinea, suggesting that this species has a wide geographical distribution. <i>C</i>. <i>arcuatus</i> covers a wider host range in Taiwan waters, inhabiting <i>Montipora</i> spp. and <i>Porites</i> spp., which suggests that the host specificity of coral-associated barnacles varies with host availability. <i>C</i>. cf. <i>euspinulosum</i> probably has a very narrow distribution and host usage. The sequences of <i>C</i>. cf. <i>euspinulosum</i> on Jeju Island do not match those of any known sequences of <i>Cantellius</i> barnacles in the Indo-Pacific region. <i>P</i>. <i>oulastreae</i> probably prefers cold water because it has been reported in temperate regions. Coral-associated barnacles in marginal communities have considerably lower diversity than their subtropical and tropical counterparts. When host availability is limited, marginal coral-associated barnacles exhibit higher host specificity than those in subtropical and tropical reef systems.</p></div

Global outbreaks of scrub typhus.

<p>Global outbreaks of scrub typhus.</p

Global seroprevalence of scrub typhus by Region/Country.

<p>Global seroprevalence of scrub typhus by Region/Country.</p

Biocompatible 2D Titanium Carbide (MXenes) Composite Nanosheets for pH-Responsive MRI-Guided Tumor Hyperthermia

The emerging of two-dimensional (2D) MXenes significantly broadens the family members and versatile applications of 2D materials, but the rational design of MXene-based composites and their specific applications in theranostic biomedicine are still challenging. In this work, we report, for the first time, on the elaborate design of the Ti₃C₂-based composite MXene (MnO_<i>x</i>/Ti₃C₂) for highly efficient theranostic applications against cancer. These MnO_<i>x</i>/Ti₃C₂ composite MXenes have been constructed by triggering a simple redox reaction to <i>in situ</i> grow small MnO_<i>x</i> nanosheets on the surface of Ti₃C₂. These MnO_<i>x</i>/Ti₃C₂ composite MXenes have been developed as multifunctional theranostic agents for efficient magnetic resonance (MR) and photoacoustic (PA) dual-modality imaging-guided photothermal therapy (PTT) against cancer. Especially, the decoration of the MnO_<i>x</i> component onto MnO_<i>x</i>/Ti₃C₂ realizes the unique tumor microenvironment-responsive T₁-weighted MR imaging of tumors, and the high photothermal-conversion performance not only endows the MnO_<i>x</i>/Ti₃C₂ with desirable contrast-enhanced PA-imaging property but also realizes the highly efficient tumor ablation and tumor-growth suppression. The <i>in vivo</i> biocompatibility of these MnO_<i>x</i>/Ti₃C₂–SP composite nanosheets has also been systematically evaluated and revealed. This work not only paves a new way for the multifunctionalization of 2D MXenes simply by integrating other functional components but also broadens their versatile applications in theranostic nanomedicine

Characteristics of scrub typhus in main endemic areas.

<p>Characteristics of scrub typhus in main endemic areas.</p

Mean K2P distance for concatenated dataset between and within the studied species.

<p>Mean K2P distance for concatenated dataset between and within the studied species.</p

Coral host usage by barnacles <i>Cantellius arcuatus</i>, <i>C</i>. cf. <i>euspinulosum</i> and <i>Pyrgomina oulastreae</i> in Jeju Island.

<p>Note <i>C</i>. <i>arcuatus</i> and <i>C</i>. cf. <i>euspinulosum</i> were 100% found on the coral <i>Montipora millepora</i> and <i>Alveopora japonica</i> respectively. <i>Pyrgomina oulastreae</i> are found on both <i>Psammocora</i> spp. and <i>Osulastrea crispata</i>. <i>Psammocora</i> spp. include both <i>P</i>. <i>profundacella</i> and <i>P</i>. <i>albopicta</i>.</p

Relative abundance of scleractinian corals in south and west waters of Seop Seom and Beom Seom off of Jeju waters from 30 metres transect surveys.

<p><i>Psammocora</i> spp. include both <i>P</i>. <i>profundacella</i> and <i>P</i>. <i>albopicta</i>, which are difficult to identify <i>in situ</i> in the field without examining the columellae structure from the coral skeleton. Non-coral surfaces were colonized by soft corals, kelps and sponges.</p

Phylogenetic tree for coral-associated barnacles based on maximum likelihood analysis of the two mitochondrial gene datasets, using <i>A</i>. <i>amphitrite</i> as outgroup.

<p>Bootstrap scores > 80 are presented at the major nodes. The scale bar indicates the number of substitutions per site.</p

Map of Jeju Island, Korea.

<p>Showing the collection sites of coral-associated barnacles used in this study.</p