Significant improvements to the thermoelectric figure of merit ZT have emerged in recent years, primarily due to the engineering of material composition and nanostructure in inorganic semiconductors (ISCs). However, many present high-ZT materials are based on low-abundance elements that pose challenges for scale-up, as they entail high material costs in addition to brittleness and difficulty in large-area deposition. Here we demonstrate a strategy to improve ZT in conductive polymers and other organic semiconductors (OSCs) for which the base elements are earth-abundant. By minimizing total dopant volume, we show that all three parameters constituting ZT vary in a manner so that ZT increases; this stands in sharp contrast to ISCs, for which these parameters have trade-offs. Reducing dopant volume is found to be as important as optimizing carrier concentration when maximizing ZT in OSCs. Implementing this strategy with the dopant poly(styrenesulphonate) in poly(3,4-ethylenedioxythiophene), we achieve ZT  =  0.42 at room temperature.

Spermatogenesis is a differentiation process during which diploid spermatogonial stem cells (SSCs) produce haploid spermatozoa. This highly specialized process is precisely controlled at the transcriptional, posttranscriptional, and translational levels. Here we report that N-methyladenosine (mA), an epitranscriptomic mark regulating gene expression, plays essential roles during spermatogenesis. We present comprehensive mA mRNA methylomes of mouse spermatogenic cells from five developmental stages: undifferentiated spermatogonia, type A spermatogonia, preleptotene spermatocytes, pachytene/diplotene spermatocytes, and round spermatids. Germ cell-specific inactivation of the mA RNA methyltransferase Mettl3 or Mettl14 with Vasa-Cre causes loss of mA and depletion of SSCs. mA depletion dysregulates translation of transcripts that are required for SSC proliferation/differentiation. Combined deletion of Mettl3 and Mettl14 in advanced germ cells with Stra8-GFPCre disrupts spermiogenesis, whereas mice with single deletion of either Mettl3 or Mettl14 in advanced germ cells show normal spermatogenesis. The spermatids from double-mutant mice exhibit impaired translation of haploid-specific genes that are essential for spermiogenesis. This study highlights crucial roles of mRNA mA modification in germline development, potentially ensuring coordinated translation at different stages of spermatogenesis.

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The Chinese giant salamander Andrias davidianus is the largest living amphibian. Most wild populations are threatened and some are already extinct. The Chinese government has declared the species a Class II Protected Species, and it is listed as Critically Endangered in the Chinese Red Book of Amphibians and Reptiles and as Data Deficient on the IUCN Red List. Populations of the species have declined sharply in both range and number since the 1950s because of habitat loss and fragmentation, and hunting for the commercial luxury food trade. Remaining populations appear to be distributed in 12 areas across 17 provinces in the mountainous areas of the middle Yangtze, Yellow and Pearl Rivers. Since the 1980s, 14 nature reserves, with a total area of more than 355,000 ha, have been established for the conservation of the Chinese giant salamander. We carried out habitat and questionnaire surveys for the species in 13 locations, and based on the results and on the little amount of published information, most of it in Chinese, we assess the current status of the species and make recommendations for its conservation management. Conservation of the Chinese giant salamander should be given a high priority and considered an important part of wetland management.

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Summary Fruit rind plays a pivotal role in alleviating water loss and disease and particularly in cracking resistance as well as the transportability, storability and shelf‐life quality of the fruit. High susceptibility to cracking due to low rind hardness is largely responsible for severe annual yield losses of fresh fruits such as watermelon in the field and during the postharvest process. However, the candidate gene controlling the rind hardness phenotype remains unclear to date. Herein, we report, for the first time, an ethylene‐responsive transcription factor 4 (ClERF4) associated with variation in rind hardness via a combinatory genetic map with bulk segregant analysis (BSA). Strikingly, our fine‐mapping approach revealed an InDel of 11 bp and a neighbouring SNP in the ClERF4 gene on chromosome 10, conferring cracking resistance in F2 populations with variable rind hardness. Furthermore, the concomitant kompetitive/competitive allele‐specific PCR (KASP) genotyping data sets of 104 germplasm accessions strongly supported candidate ClERF4 as a causative gene associated with fruit rind hardness variability. In conclusion, our results provide new insight into the underlying mechanism controlling rind hardness, a desirable trait in fresh fruit. Moreover, the findings will further enable the molecular improvement of fruit cracking resistance in watermelon via precisely targeting the causative gene relevant to rind hardness, ClERF4.