Knockout of OsSWEET15 Impairs Rice Embryo Formation and Seed-Setting.

We show that the knockout of a sugar transporter gene OsSWEET15 led to a significant drop in rice fertility with around half of the knockout mutant's spikelets bearing blighted or empty grains. The rest of the spikelets bore fertile grains with a slightly reduced weight. Notably, the ovaries in the blighted grains of the ossweet15 mutants expanded after flowering but terminated their development before the endosperm cellularization stage and subsequently aborted. ß- glucuronidase (GUS) and Green Fluorescent Protein (GFP) reporter lines representing the OsSWEET15 expression showed that the gene was expressed in the endosperm tissues surrounding the embryo, which supposedly supplies nutrients to sustain embryo development. These results together with the protein's demonstrated sucrose transport capacity and plasma membrane localization suggest that OsSWEET15 plays a prominent role during the caryopsis formation stage, probably by releasing sucrose from the endosperm to support embryo development. By contrast, the empty grains were probably caused by the reduced pollen viability of the ossweet15 mutants. Investigation of ossweet11 mutant grains revealed similar phenotypes to those observed in the ossweet15 mutants. These results indicate that both OsSWEET15 and OsSWEET11 play important and similar roles in rice pollen development, caryopsis formation and seed-setting, in addition to their function in seed-filling that was demonstrated previously.

Chromatin-remodeling factor CHR721 with non-canonical PIP-box interacts with OsPCNA in Rice.

BACKGROUND: Proliferating cell nuclear antigen (PCNA) is one of the key factors for the DNA replication process and DNA damage repair. Most proteins interacting with PCNA have a common binding motif: PCNA interacting protein box (PIP box). However, some proteins with non-canonical PIP-box have also been reported to be the key factors that interacted with PCNA. RESULTS: Here we discovered the C terminal of a chromatin-remodeling factor CHR721 with non-canonical PIP-box was essential for interacting with OsPCNA in rice. Both OsPCNA and CHR721 were localized in the nuclei and function in response to DNA damages. CONCLUSIONS: Based on the results and previous work, we proposed a working model that CHR721 with non-canonical PIP-box interacted with OsPCNA and both of them probably participate in the DNA damage repair process.

The Harbinger transposon-derived gene PANDA epigenetically coordinates panicle number and grain size in rice.

Transposons significantly contribute to genome fractions in many plants. Although numerous transposon-related mutations have been identified, the evidence regarding transposon-derived genes regulating crop yield and other agronomic traits is very limited. In this study, we characterized a rice Harbinger transposon-derived gene called PANICLE NUMBER AND GRAIN SIZE (PANDA), which epigenetically coordinates panicle number and grain size. Mutation of PANDA caused reduced panicle number but increased grain size in rice, while transgenic plants overexpressing this gene showed the opposite phenotypic change. The PANDA-encoding protein can bind to the core polycomb repressive complex 2 (PRC2) components OsMSI1 and OsFIE2, and regulates the deposition of H3K27me3 in the target genes, thereby epigenetically repressing their expression. Among the target genes, both OsMADS55 and OsEMF1 were negative regulators of panicle number but positive regulators of grain size, partly explaining the involvement of PANDA in balancing panicle number and grain size. Moreover, moderate overexpression of PANDA driven by its own promoter in the indica rice cultivar can increase grain yield. Thus, our findings present a novel insight into the epigenetic control of rice yield traits by a Harbinger transposon-derived gene and provide its potential application for rice yield improvement.

Endoscopic stent versus diverting stoma as a bridge to surgery for obstructive colorectal cancer: a systematic review and meta-analysis.

BACKGROUND: Self-expandable metallic stent (SEMS), an alternative to diverting stoma (DS), has been used as a "bridge to surgery" (BTS) to decompress acute obstruction of colorectal cancer (CRC) for decades. However, whether SEMS is a safe technique for obstruction of CRC without compromising the long-term survival of patients remains unidentified compared to those of DS. The aim of the present study was to elucidate the safety and survival outcomes of SEMS and DS. METHODS: Embase, PubMed, and Medline were searched for qualified studies published until October, 2020, in which SEMS or DS was performed as a BTS without resection at the same stage. The last search was on December 5th, 2020. The Newcastle-Ottawa scale (NOS) was used to assess the quality of included studies. The major complication rate, mortality, 3-year overall survival (OS), and permanent stoma rate were estimated as outcomes. RESULTS: The present study was registered on INPLASY (No. 2020100079). Seven eligible studies were included, involving 646 and 712 patients who underwent SEMS and DS treatments, respectively. The Clavien-Dindo I/II grade complication rate was significantly lower in the SEMS group than in the DS group (8.68 vs. 16.85%; RR, 0.59; 95% confidence interval (CI) 0.41-0.84; P = 0.004). The Clavien-Dindo III/IV grade complication rate was comparable in two groups (7.69 vs. 8.79%; RR, 0.82; 95% CI 0.54-1.27; P = 0.37). There were no statistical differences in the short-term mortality (5.16 vs. 4.53%; RR, 1.25; 95% CI 0.75-2.08; P = 0.39), 3-year OS (71.91 vs. 76.60%; RR, 0.93; 95% CI 0.86-1.01; P = 0.10), and permanent stoma rate (22.08 vs. 27.54%; RR, 0.84; 95% CI 0.67-1.06; P = 0.14) between the two groups. CONCLUSIONS: To some extent, SEMS is a safe BTS technique for acute obstructive CRC, without significant adverse effect on the survival of patients. Given the advantage of minimal invasion, SEMS may be a better alternative to DS for obstructive CRC. However, the conclusions remain to be discussed because of lacking high-quality randomized controlled trails.

Molecular identification and expression analysis of five sucrose synthase genes in Sorghum Bicolor.

In higher plants, sucrose synthase (Susy, EC 2.4.1.13) as an enzyme with a core function, involved in the synthesis and breakdown of sugars, and plays an important role in growth and metabolism. Although, the different genes encoding Susy isozyme proteins have been cloned and functionally verified in several plant species, to date detailed information about the Susy genes is lacking in Sorghum. Here, we demonstrated the identification of five novel Susy genes from the sorghum genome database. Sequence, structure and phylogenetic analyses of these five SbSusy genes revealed evolutionary conservation through Susy gene family members across Sorghum and other crop plants. The expression of sorghum Susy genes was investigated via transcriptome database in various developmental stages and different tissues. Further qRT-PCR was performed to reveal the induction of SbSusy genes under salt, drought and sugar induction. The results indicated that all Susy genes were differentially expressed in various tissues and highly associated with sucrose metabolism. This study shows a theoretical reference of Susy genes in Sorghum, which provides new insights for the knowledge of the evolution relationships, and basic information to help clarify the molecular mechanism of Susy synthase genes in Sorghum. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-022-01166-8.

China's "Weaponized" Vaccine: Intertwining Between International and Domestic Politics.

Ever since China has formally joined the WHO-backed global COVID-19 vaccine initiative known as COVAX, there is a presumed notion that China's vaccine diplomacy will make a significant contribution to the international public good and thus uplift Beijing's role as the rule-maker of international order. To scrutinize this, the paper asks if China succeeded in proliferating its weaponized vaccine policy to obtain maximum diplomatic gains and soft power projection to intensify its international image, geopolitical power, and domestic politico legitimacy. The authors argue that despite its vaccine diplomacy demonstrated the robust governance capacity and responsibility to be a great power. Yet, Beijing's geopolitical influence and international image are significantly overrated and not enough to play a more prominent role in the global power fulcrum/equilibrium. On the contrary, China enjoys a leading position on the domestic political front. Its successful portrayal of China's vaccine provision in the global market and remarkable configuration to leverage a deep-rooted nationalism has fundamentally provided China with a powerful rationale to divert its public's attention from Beijing's earlier inadequate handling of the outbreak. The evaluation of the paper reveals that China's vaccine diplomacy's influence in promoting international image and geopolitics is limited but has successfully stabilized its domestic political environment and enhanced its domestic legitimacy.

Identification of GROWTH-REGULATING FACTOR transcription factors in lettuce (Lactuca sativa) genome and functional analysis of LsaGRF5 in leaf size regulation.

BACKGROUND: GROWTH-REGULATING FACTORs (GRFs), a type of plant-specific transcription factors, play important roles in regulating plant growth and development. Although GRF gene family has been identified in various plant species, a genome-wide analysis of this family in lettuce (Lactuca sativa L.) has not been reported yet. RESULTS: Here we identified 15 GRF genes in lettuce and performed comprehensive analysis of them, including chromosomal locations, gene structures, and conserved motifs. Through phylogenic analysis, we divided LsaGRFs into six groups. Transactivation assays and subcellular localization of LsaGRF5 showed that this protein is likely to act as a transcriptional factor in the cell nucleus. Furthermore, transgenic lettuce lines overexpressing LsaGRF5 exhibited larger leaves, while smaller leaves were observed in LsaMIR396a overexpression lines, in which LsaGRF5 was down-regulated. CONCLUSIONS: These results in lettuce provide insight into the molecular mechanism of GRF gene family in regulating leaf growth and development and foundational information for genetic improvement of the lettuce variations specialized in leaf character.

Transcriptome sequencing analysis of sorghum callus with various regeneration capacities.

MAIN CONCLUSION: The possible molecular mechanisms regulating sorghum callus regeneration were revealed by RNA-sequencing. Plant callus regeneration has been widely applied in agricultural improvement. Recently, callus regeneration has been successfully applied in the genetic transformation of sorghum by using immature sorghum embryos as explants. However, the mechanism underlying callus regeneration in sorghum is still largely unknown. Here, we describe three types of callus (Callus I-III) with different redifferentiation abilities undergoing distinct induction from immature embryos of the Hiro-1 variety. Compared with nonembryonic Callus III, Callus I produced only some identifiable roots, and embryonic Callus II was sufficient to regenerate whole plants. Genome-wide transcriptome profiles were generated to reveal the underlying mechanisms. The numbers of differentially expressed genes for the three types of callus varied from 5906 to 8029. In accordance with the diverse regeneration abilities observed for different types of callus and leaf tissues, the principal component analysis revealed that the gene expression patterns of Callus I and Callus II were different from those of Callus III and leaves regenerated from Callus II. Notably, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses, pharmacological treatment, and substance content determinations revealed that plant ribosomes, lignin metabolic processes, and metabolism of starch and sucrose were significantly enriched, suggesting that these factors are associated with callus regeneration. These results helped elucidate the molecular regulation of three types of callus with different regeneration abilities in sorghum.

Rice SUT and SWEET Transporters.

Sugar transporters play important or even indispensable roles in sugar translocation among adjacent cells in the plant. They are mainly composed of sucrose-proton symporter SUT family members and SWEET family members. In rice, 5 and 21 members are identified in these transporter families, and some of their physiological functions have been characterized on the basis of gene knockout or knockdown strategies. Existing evidence shows that most SUT members play indispensable roles, while many SWEET members are seemingly not so critical in plant growth and development regarding whether their mutants display an aberrant phenotype or not. Generally, the expressions of SUT and SWEET genes focus on the leaf, stem, and grain that represent the source, transport, and sink organs where carbohydrate production, allocation, and storage take place. Rice SUT and SWEET also play roles in both biotic and abiotic stress responses in addition to plant growth and development. At present, these sugar transporter gene regulation mechanisms are largely unclear. In this review, we compare the expressional profiles of these sugar transporter genes on the basis of chip data and elaborate their research advances. Some suggestions concerning future investigation are also proposed.

CHR721, interacting with OsRPA1a, is essential for both male and female reproductive development in rice.

KEY MESSAGE: CHR721 functions as a chromatin remodeler and interacts with a known single-stranded binding protein, OsRPA1a, to regulate both male and female reproductive development in rice. Reproductive development and fertility are important for seed production in rice. Here, we identified a sterile rice mutant, chr721, that exhibited defects in both male and female reproductive development. Approximately 5% of the observed defects in chr721, such as asynchronous dyad division, occurred during anaphase II of meiosis. During the mitotic stage, approximately 80% of uninucleate microspores failed to develop into tricellular pollen, leading to abnormal development. In addition, defects in megaspore development were detected after functional megaspore formation. CHR721, which encodes a nuclear protein belonging to the SNF2 subfamily SMARCAL1, was identified by map-based cloning. CHR721 was expressed in various tissues, especially in spikelets. CHR721 was found to interact with replication protein A (OsRPA1a), which is involved in DNA repair. The expressions of genes involved in DNA repair and cell-cycle checkpoints were consistently upregulated in chr721. Although numerous genes involved in male and female development have been identified, the mode of participation of chromatin-remodeling factors in reproductive development is still not well understood. Our results suggest that CHR721, a novel gene cloned from rice, plays a vital role in both male and female reproductive development.

Revealing the influence of microbiota on the quality of Pu-erh tea during fermentation process by shotgun metagenomic and metabolomic analysis.

Multispecies microbial community in natural solid-state fermentation (SSF) is crucial for the formation of Chinese Pu-erh tea's unique quality. However, the association between microbiota and tea quality are still poorly understood. Herein, shotgun metagenomic and metabolomic analysis showed that significant variations in composition of microbiota, collective functional genes, and flavour compounds occurred during SSF process. Furthermore, the formation pathways of the dominant flavours including theabrownin, methoxy-phenolic compound, alcohol and carvone were proposed. Moreover, biological interaction networks analysis among functional core microbiota, functional genes, and dominant flavours indicated Aspergillus was the main flavour-producing microorganism in the early SSF, while many other genera including Bacillus, Rasamsonia, Lichtheimia, Debaryomyces were determined as the functional core microorganism for flavours production in the late SSF. This study provides a perspective for bridging the gap between the microbiota and quality in Pu-erh tea, and benefited for further optimizing production efficiency and product quality.

[Threshold temperature and effective accumulative temperature of Periplaneta Americana].

Periplaneta americana is an important medicinal insect. A series of new drugs developed from it have remarkable clinical effects and are in great demand in the market. Because of unclear biology, the quality and yield of P. americana are affected. Understanding the developmental threshold temperature and effective accumulated temperature of P. americana can provide theoretical basis for standardized culture of P.americana. Under climate chamber, the threshold temperature and effective accumulated temperature for egg development of P. americana to were determined through effective accumulated temperature law. The threshold temperature was （15.8±0.71）°C, the effective accumulated temperature was 415.8±38.05 degree days. A model of the relationship between temperature and developmental rates was established.

Essential Role of Sugar Transporter OsSWEET11 During the Early Stage of Rice Grain Filling.

This study investigated the role of the sugar transporter OsSWEET11 during the early stage of rice caryopsis development using ß-glucoronidase (GUS) to represent its expression, together with clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR-Cas9)-mediated knockout, cross-fertilization and RNA sequencing (RNA-seq) analyses. The results showed that OsSWEET11 was expressed strongly in developing caryopsis, particularly in the ovular vascular trace, nucellar epidermis and cross cells. The knockout of OsSWEET11 significantly decreased the sucrose concentration in the mutant embryo sacs and led to defective grain filling compared with that of the wild-type (WT) plant. Moreover, the expression of 2,549 genes in the mutant caryopsis was affected. The grain weight and seed setting percentage were also decreased in the mutants. The cross-fertilization of the mutant and WT rice revealed that the mutated maternal donor induced defective grain filling. These results strongly suggested that OsSWEET11 played an important role in sucrose release from maternal tissue to the maternal-filial interface during the early stage of caryopsis development. It might also induce sucrose release from the ovular vascular trace and cross cells of developing caryopsis. These findings bridge the gap in the understanding of post-phloem sugar transport during the early stage of rice caryopsis development.

Phylogenetic evidence for a fusion of archaeal and bacterial SemiSWEETs to form eukaryotic SWEETs and identification of SWEET hexose transporters in the amphibian chytrid pathogen Batrachochytrium dendrobatidis.

SWEETs represent a new class of sugar transporters first described in plants, animals, and humans and later in prokaryotes. Plant SWEETs play key roles in phloem loading, seed filling, and nectar secretion, whereas the role of archaeal, bacterial, and animal transporters remains elusive. Structural analyses show that eukaryotic SWEETs are composed of 2 triple-helix bundles (THBs) fused via an inversion linker helix, whereas prokaryotic SemiSWEETs contain only a single THB and require homodimerization to form transport pores. This study indicates that SWEETs retained sugar transport activity in all kingdoms of life, and that SemiSWEETs are likely their ancestral units. Fusion of oligomeric subunits into single polypeptides during evolution of eukaryotes is commonly found for transporters. Phylogenetic analyses indicate that THBs of eukaryotic SWEETs may not have evolved by tandem duplication of an open reading frame, but rather originated by fusion between an archaeal and a bacterial SemiSWEET, which potentially explains the asymmetry of eukaryotic SWEETs. Moreover, despite the ancient ancestry, SWEETs had not been identified in fungi or oomycetes. Here, we report the identification of SWEETs in oomycetes as well as SWEETs and a potential SemiSWEET in primitive fungi. BdSWEET1 and BdSWEET2 from Batrachochytrium dendrobatidis, a nonhyphal zoosporic fungus that causes global decline in amphibians, showed glucose and fructose transport activities.-Hu, Y.-B., Sosso, D., Qu, X.-Q., Chen, L.-Q., Ma, L., Chermak, D., Zhang, D.-C., Frommer, W. B. Phylogenetic evidence for a fusion of archaeal and bacterial SemiSWEETs to form eukaryotic SWEETs and identification of SWEET hexose transporters in the amphibian chytrid pathogen Batrachochytrium dendrobatidis.

[A Mononuclear Terbium(â ¢) Complex Constructed with 2,2'-Oxybis (benzoic acid) and 1,10-Phenanthroline: Fluorescence and Fluorescent Sensing for Fe3+ ion].

New complex [Tb(2,2'-oba)2(phen)2]-(H+3O) (2,2'-oba=2,2'-oxybis(benzoic acid), phen=1,10-phenanthroline) was synthesized under hydrothermal condition and characterized with X-ray single crystal diffraction. Complex reveals mononuclear structure containing TbO4N4 unit. Complex displays the emission peaks at 489，546，584 and 622 nm, corresponding to the 5D4→7FJ(J=6-3) transitions of Tb(Ⅲ) ion. The emission band at 546 nm corresponds to the 5D4→7F5 transition of the Tb(Ⅲ) ion, which gives an intense green luminescence output for the solid sample. The recognition for metal ions was discussed with fluorescent spectroscopy. The results show that it has high selectivity for Fe3+ via a fluorescence quenching mechanism. Luminescent investigations reveal that it can detect Fe3+ with relatively high sensitivity and selectivity, even when pH 4.0～8.0，which leads to its application in biotic and environmental system.

Multiple cold resistance loci confer the high cold tolerance adaptation of Dongxiang wild rice (Oryza rufipogon) to its high-latitude habitat.

KEY MESSAGE: Dongxiang wild rice is phylogenetically close to temperate japonica and contains multiple cold resistance loci conferring its adaptation to high-latitude habitat. Understanding the nature of adaptation in wild populations will benefit crop breeding in the development of climate-resilient crop varieties. Dongxiang wild rice (DXWR), the northernmost common wild rice known, possesses a high degree of cold tolerance and can survive overwintering in its native habitat. However, to date, it is still unclear how DXWR evolved to cope with low-temperature environment, resulting in limited application of DXWR in rice breeding programs. In this study, we carried out both QTL mapping and phylogenetic analysis to discern the genetic mechanism underlying the strong cold resistance. Through a combination of interval mapping and single locus analysis in two genetic populations, at least 13 QTLs for seedling cold tolerance were identified in DXWR. A phylogenetic study using both genome-wide InDel markers and markers associated with cold tolerance loci reveals that DXWR belongs to the Or-III group, which is most closely related to cold-tolerant Japonica rice rather than to the Indica cultivars that are predominant in the habitat where DXWR grows. Our study paves the way toward an understanding of the nature of adaptation to a northern habitat in O. rufipogon. The QTLs identified in DXWR in this study will be useful for molecular breeding of cold-tolerant rice.

THIS1 is a putative lipase that regulates tillering, plant height, and spikelet fertility in rice.

Proper branching and successful reproductive growth is of great importance for rice productivity. Substantial progress has been made in uncovering the molecular mechanisms underlying tillering control and spikelet sterility. However, rice tillering is developmentally controlled, and how it is regulated coordinately with reproductive growth remains unclear. This study characterized a rice mutant, the most obvious phenotypes of which are high tillering, reduced height, and infertile spikelets (named this1). Similarly to the high tiller number and dwarf mutants in rice, the increased tiller number of this1 plants is ascribed to the release of tiller bud outgrowth rather than to increased tiller bud formation. In the this1 mutant, however, the accelerated rate of branching was delayed until the stem elongation stage, while other mutants lost the ability to control branching at all developmental stages. The seed-setting rate of this1 was less than half that of the wild type, owing to defects in pollen maturation, anther dehiscence, and flower opening. Histological analyses showed that the mutation in this1 resulted in anisotropic cell expansion and cell division. Using a map-based cloning approach, This1 was found to encode a class III lipase. Homology searches revealed that THIS1 is conserved in both monocots and eudicots, suggesting that it plays fundamental role in regulating branch and spikelet fertility, as well as other aspects of developmental control. The relative change in expression of marker genes highlighted the possibility that This1 is involved in phytohormone signalling pathways, such as those for strigolactone and auxin. Thus, This1 provides joint control between shoot branching and reproductive development.

The softening of Chinese digital propaganda: Evidence from the People's Daily Weibo account during the pandemic.

Introduction: Social media infuses modern relationships with vitality and brings a series of information dissemination with subjective consciousness. Studies have indicated that official Chinese media channels are transforming their communication style from didactic hard persuasion to softened emotional management in the digital era. However, previous studies have rarely provided valid empirical evidence for the communicational transformation. The study fills the gap by providing a longitudinal time-series analysis to reveal the pattern of communication of Chinese digital Chinese official media from 2019 to 2022. Method: The study crawler collected 43,259 posts from the People's Daily's Weibo account from 2019 to 2021. The study analyzed the textual data with using trained artificial intelligence models. Results: This study explored the practices of the People's Daily's Weibo account from 2019 to 2021, COVID-19 is hardly normalized as it is still used as the justification for extraordinary measures in China. This study confirmed that People's Daily's Weibo account posts are undergoing softenization transformation, with the use of soft news, positive energy promotion, and the embedding of sentiment. Although the outburst of COVID-19 temporarily increased the media's use of hard news, it only occur at the initial stage of the pandemic. Emotional posts occupy a nonnegligible amount of the People's Daily Weibo content. However, the majority of posts are emotionally neutral and contribute to shaping the authoritative image of the party press. Discussion: Overall, the People's Daily has softened their communication style on digital platforms and used emotional mobilization, distraction, and timely information provision to balance the political logic of building an authoritative media agency and the media logic of constructing audience relevance.

Global Decrease in H3K9 Acetylation in Sorghum Seed Postgermination Stages.

Sorghum seed germination is accompanied by increases in nutrient contents and reduced levels of antinutrients and is therefore being applied to food processing. However, the characterization of acetylated histone H3 at lysine residue 9 (H3K9ac) in sorghum postgermination has lagged. In this study, we performed chromatin immunoprecipitation sequencing (ChIP-seq) to identify H3K9ac enrichment and obtained transcriptome in postgermination stages. More than 10,000 hypoacetylated genes gained H3K9ac marks in the postgermination stages. In addition, we observed that the expression of the main histone deacetylase (HDAC) genes was elevated. The application of the HDAC inhibitor trichostatin A (TSA) resulted in seed growth arrest, suggesting that the repression of the H3K9ac modification is critical for postgermination. Additionally, we obtained a comprehensive view of abundant genomic changes in H3K9ac-marked regions and transcription between the mock and TSA treatment groups, which suggested that H3K9ac was required in the late stage of autotrophic seedling establishment. Metabolic profiling, transcriptome analyses, and ChIP-seq revealed that H3K9ac is enriched at genes involved in phenylpropanoid, including lignin and flavonoid, biosynthesis. Our results suggest important roles of H3K9ac in sorghum seed postgermination stages.

Nanobacteria may be linked to calcification in placenta.

AIMS: Placental calcification is a common pathologic condition in obstetrics. To detect the bacteria infection mechanisms for calcification, an experiment was performed to isolate, culture, and identify the nanobacteria in placental calcification. METHOD: Sixteen cases of placental calcification of pregnant women were collected for the purpose of the isolation of nanobacteria, cultivation, and identification of 16S rDNA sequence. RESULT: Under transmission electron microscope, novel oval-shape nanobacteria-like particles (NLP) in extracellular matrix of calcified placenta tissues were found with 50-500 nm in diameter, and among hydroxyapatite crystals aggregation existed. After about 4 weeks of culturing and isolating NLP from these calcified tissues, all calcified placental tissue samples and one adjacent tissue of calcified placental tissue samples showed white granular depositions, which were firmly attached to the bottom of the culture tubes and visible to the naked eyes. In the control group they could not be seen. After PCR was amplified a 1407-bp fragment was obtained and submitted to GenBank after sequencing with accession number JN029830. The 16S rDNA sequence homology between the isolation strain and strain nanobacteria (X98418) was 92% in GenBank. CONCLUSION: For the first time isolated, cultured, and identified nanobacteria in placental calcification indicated that nanobacteria infection is related to placental calcification.