Mutation of a Conserved Motif of PP2C.D Phosphatases Confers SAUR Immunity and Constitutive Activity

The phytohormone auxin promotes the growth of plant shoots by stimulating cell expansion via plasma membrane (PM) H⁺-ATPase activation, which facilitates cell wall loosening and solute uptake. Mechanistic insight was recently obtained by demonstrating that auxin-induced SMALL AUXIN UP RNA (SAUR) proteins inhibit D-CLADE TYPE 2C PROTEIN PHOSPHATASE (PP2C.D) activity, thereby trapping PM H⁺-ATPases in the phosphorylated, activated state, but how SAURs bind PP2C.D proteins and inhibit their activity is unknown. Here, we identified a highly conserved motif near the C-terminal region of the PP2C.D catalytic domain that is required for SAUR binding in Arabidopsis (Arabidopsis thaliana). Missense mutations in this motif abolished SAUR binding but had no apparent effect on catalytic activity. Consequently, mutant PP2C.D proteins that could not bind SAURs exhibited constitutive activity, as they were immune to SAUR inhibition. In planta expression of SAUR-immune pp2c.d2 or pp2c.d5 derivatives conferred severe cell expansion defects and corresponding constitutively low levels of PM H⁺-ATPase phosphorylation. These growth defects were not alleviated by either auxin treatment or 35S:StrepII-SAUR19 coexpression. In contrast, a PM H⁺-ATPase gain-of-function mutation that results in a constitutively active H⁺ pump partially suppressed SAUR-immune pp2c.d5 phenotypes, demonstrating that impaired PM H⁺-ATPase function is largely responsible for the reduced growth of the SAUR-immune pp2c.d5 mutant. Together, these findings provide crucial genetic support for SAUR-PP2C.D regulation of cell expansion via modulation of PM H⁺-ATPase activity. Furthermore, SAUR-immune pp2c.d derivatives provide new genetic tools for elucidating SAUR and PP2C.D functions and manipulating plant organ growth.

Large debris dumps in the northern South China Sea

Knowledge of the abundance, source, and fate of marine debris in the deep sea is largely constrained thus far. Here, we report the existence of large deep-sea debris dumps that have not been reported before on the seafloor worldwide. Marine debris remarkably accumulated at ~1700-1800 m in the tributary submarine canyons of the Xisha Trough, northern South China Sea (SCS). Although marine debris in Xisha Trough is patchy, the debris abundance was as high as 36,818 and 51,929 items/km² at locations SY78 and SY82, respectively, which is one order of magnitude higher than that in other submarine canyons. We propose that most of the debris came from fishery and navigation activities, as indicated by the categories of debris collected from the seafloor dumps. Seasonal surface ocean currents of the SCS and geomorphology of submarine canyons possibly influence the movement of the debris from coasts to the deep seafloor.

Elastocapillary self-assembled neurotassels for stable neural activity recordings

Implantable neural probes that are mechanically compliant with brain tissue offer important opportunities for stable neural interfaces in both basic neuroscience and clinical applications. Here, we developed a Neurotassel consisting of an array of flexible and high-aspect ratio microelectrode filaments. A Neurotassel can spontaneously assemble into a thin and implantable fiber through elastocapillary interactions when withdrawn from a molten, tissue-dissolvable polymer. Chronically implanted Neurotassels elicited minimal neuronal cell loss in the brain and enabled stable activity recordings of the same population of neurons in mice learning to perform a task. Moreover, Neurotassels can be readily scaled up to 1024 microelectrode filaments, each with a neurite-scale cross-sectional footprint of 3 × 1.5 μm², to form implantable fibers with a total diameter of ~100 μm. With their ultrasmall sizes, high flexibility, and scalability, Neurotassels offer a new approach for stable neural activity recording and neuroprosthetics.

MYC2 Regulates the Termination of Jasmonate Signaling via an Autoregulatory Negative Feedback Loop

In tomato (Solanum lycopersicum), as in other plants, the immunity hormone jasmonate (JA) triggers genome-wide transcriptional changes in response to pathogen and insect attack. These changes are largely regulated by the basic helix-loop-helix (bHLH) transcription factor MYC2. The function of MYC2 depends on its physical interaction with the MED25 subunit of the Mediator transcriptional coactivator complex. Although much has been learned about the MYC2-dependent transcriptional activation of JA-responsive genes, relatively less studied is the termination of JA-mediated transcriptional responses and the underlying mechanisms. Here, we report an unexpected function of MYC2 in regulating the termination of JA signaling through activating a small group of JA-inducible bHLH proteins, termed MYC2-TARGETED BHLH1 (MTB1), MTB2, and MTB3. MTB proteins negatively regulate JA-mediated transcriptional responses via their antagonistic effects on the functionality of the MYC2-MED25 transcriptional activation complex. MTB proteins impair the formation of the MYC2-MED25 complex and compete with MYC2 to bind to its target gene promoters. Therefore, MYC2 and MTB proteins form an autoregulatory negative feedback circuit to terminate JA signaling in a highly organized manner. We provide examples demonstrating that gene editing tools such as CRISPR/Cas9 open up new avenues to exploit MTB genes for crop protection.

The comparison of thoracoscopic-laparoscopic esophagectomy and open esophagectomy: A meta-analysis

OBJECTIVE

The objective of this study was to perform a meta-analysis to evaluate the effects of thoracoscopic-laparoscopic esophagectomy (TLE) and open esophagectomy (OE) in the treatment of esophageal cancer.

METHODS

A literature search was performed using PubMed, Embase, and Google Scholar databases for relevant keywords and the medical subject headings. After we had screened further, 13 clinical trials were included in the final meta-analysis. Specific odds ratios (ORs), standardized mean differences (SMDs), mean differences (MDs), and confidence intervals (CIs) were calculated.

RESULTS

The outcomes of treatment effects included anastomotic leakage, blood loss, number of lymph nodes harvested, and operating time. Comparing OE for esophageal cancer patients, the pooled OR of anastomotic leakage was 0.89 (95% CI = [0.47, 1.68]), the pooled SMD of blood loss was - 0.56 (95% CI = [-0.77, -0.35]), the pooled MD of lymph nodes harvested was - 0.93 (95% CI = [-2.35, 0.50]), and the pooled SMD of operating time was 0.31 (95% CI = [0.02, 0.59]).

CONCLUSION

TLE was found to significantly decrease patients' blood loss. There is no difference of anastomotic leakage and the number of lymph nodes harvested between TLE and OE.

Periodontal infection with Porphyromonas gingivalis induces preterm birth and lower birth weight in rats

Preterm birth (PTB), accompanied by low birth weight (LBW) or not, is a syndrome with tremendous risk factors and long-term health consequences for children. In recent decades, overwhelming studies have shown that periodontitis contributes to prematurity and LBW. This study was conducted to determine the link between maternal periodontitis and the pathogenesis of PTB and/or LBW through a rat infection model induced by Porphyromonas gingivalis, an important periodontopathic bacterium. The murine model was established by surgically ligating the left mandibular first molars and inoculating with P. gingivalis, and then all female rats initiated mating 6 weeks post infection. The gestational day and birth weight were recorded, and blood, amniotic fluid, and placental specimens were collected. Rats with a PTB and LBW newborns were observed in the P. gingivalis-infected group. Additionally, P. gingivalis infection significantly increased the maternal serum levels of interferon-γ and interleukin-1β, whereas no significant difference in the cytokine response was observed in the amniotic fluid. Moreover, with the translocation of P. gingivalis to placentas, remarkable changes in gestational tissues were found, followed by significantly enhanced expression of Toll-like receptor 2 (TLR2) as well as Fas and Fas ligand (FasL). These results support the concept that severe cases of periodontitis caused by P. gingivalis infection may be indicative of rats being more susceptible to PTB/LBW, probably through the activation of the TLR2 and Fas/FasL pathways within the placental tissues. This study gave us new insight into how maternal periodontopathogens might be linked to placental damage and premature pathogenesis.

Calcineurin is required for male sex pheromone biosynthesis and female acceptance

Lepidoptera sex pheromone biosynthesis is regulated by pheromone biosynthesis activating neuropeptide (PBAN). PBAN regulates not only female sex pheromone biosynthesis but also male sex pheromone biosynthesis. Previous research has confirmed that PBAN regulates sex pheromone biosynthesis using Ca²⁺ as a secondary messenger in all examined species to date. However, the downstream signal of Ca²⁺ has remained elusive. In the present study, calcineurin A (CNA), a downstream signal of Ca²⁺ , was discovered in Helicoverpa armigera male hairpencil and named HaCNA. Sequence analysis demonstrated that the open reading frame of HaCNA contains 1488 nucleotides encoding 495 amino acid residues. A homology search revealed that HaCNA shares a high amino acid identity with the CNA of other insects. Developmental and spatial expression analyses revealed that the mRNA levels of HaCNA peaked at 24 h after emergence and that HaCNA expression was ubiquitous in all examined tissues. Activity analysis revealed that PBAN activates HaCNA, and a Ca²⁺ inhibitor, Lacl₃ , attenuated the effect of PBAN by decreasing HaCNA activity. Pharmacological inhibitor and RNA interference-mediated knockdown assays revealed that both activity inhibition and decreased mRNA levels of HaCNA led to a significant decrease in the production of the male sex pheromone components [octadecanol and (Z)-11 hexadecanol)] and in the efficacy of female mating acceptance. Our results demonstrate that HaCNA acts as downstream signal of PBAN/Ca²⁺ and plays an important role in PBAN-induced male sex pheromone biosynthesis and female mating acceptance.

Three-dimensional spheroid culture of adipose stromal vascular cells for studying adipogenesis in beef cattle

Protocols designed for the adipogenic differentiation of human and mouse cells are commonly used for inducing the adipogenesis of bovine stromal vascular cells. However, likely due to metabolic differences between ruminant and non-ruminant animals, these methods result in only few cells undergoing complete adipogenesis with minimal lipid droplet accumulation. Here, we discuss the development of an adipogenic differentiation protocol for bovine primary cells through a three-dimensional spheroid culture. Stromal vascular cells derived from bovine intramuscular fat were isolated and stored in liquid nitrogen before culturing. Cells were cultured in hanging drops for 3 days to allow for the formation of spherical structures. The spheroids were then transferred to cell culture plates with endothelial basal medium-2 for 3 days and in Dulbecco's Modified Eagle's Medium (DMEM) supplemented with a standard adipogenic cocktail for 3 additional days, which were then allowed to fully differentiate for 3 days in DMEM supplemented with insulin. Compared with conventional two-dimensional culture, cells in a three-dimensional spheroid culture system had higher adipogenic gene expression and consequently contained more adipocytes with larger lipid droplets. In addition, endothelial induction of spheroids prior to adipogenic differentiation is essential for efficient induction of adipogenesis of bovine stromal vascular cells, mimicking in vivo adipose development. In summary, the newly developed three-dimensional spheroid culture method is an efficient way to induce adipogenic differentiation and study adipose development of cells derived from ruminant animals, which also can be used for studying the role of angiogenesis in adipose development.

Effect of bovine lactoferrin and human lactoferrin on the proliferative activity of the osteoblast cell line MC3T3-E1 in vitro

We conducted a comparative in vitro study on the proliferative effects of natural human lactoferrin (nhLF) and bovine lactoferrin (bLF) on osteoblasts. We investigated cell proliferation, cell survival, cell cycle, and mRNA and protein expression of proliferating cell nuclear antigen. Results indicated that treatment with 100 μg/mL of bLF or nhLF promoted the proliferation and sustenance of osteoblasts, and increased the length of the G₂/M and S phases compared with the untreated osteoblasts. Results of real-time quantitative PCR and Western blot showed that mRNA and protein expression of proliferating cell nuclear antigen by osteoblasts treated with bLF or nhLF were greater than those of the untreated control. At the same concentration, bLF demonstrated a greater effect on osteoblast proliferation than did nhLF. This study provides insights of significance in the utlization of bLF in healthy food formulas.

Dose- and type-dependent effects of long-chain fatty acids on adipogenesis and lipogenesis of bovine adipocytes

Differentiation and lipid metabolism of adipocytes have a great influence on milk performance, health, and feed efficiency of dairy cows. The effects of dietary long-chain fatty acids (FA) on adipogenesis and lipogenesis of dairy cows are often confounded by other nutritional and physiological factors in vivo. Therefore, this study used an in vitro approach to study the effect of dose and type of long-chain FA on adipogenesis and lipogenesis of bovine adipocytes. Stromal vascular cells were isolated from adipose tissue of dairy cows and induced into mature adipocytes in the presence of various long-chain FA including myristic, palmitic, stearic, oleic, or linoleic acid. When concentrations of myristic, palmitic, and oleic acids in adipogenic mediums were 150 and 200 μM, the induced mature adipocytes had greater lipid content compared with other concentrations of FA. In addition, mature adipocytes induced at 100 μM stearic acid and 300 μM linoleic acid had the greatest content of lipid than at other concentrations. High concentrations of saturated FA were more toxic for cells than the same concentration of unsaturated FA during the induction. When commitment stage was solely treated with FA, the number of differentiated mature adipocytes was greater for oleic and linoleic acids than other FA. When the maturation stage was treated with FA, the number of mature adipocytes was not affected, but the lipid content in adipocytes was affected and ranked oleic > linoleic > myristic > stearic > palmitic. In summary, this study showed that adipogenesis and lipogenesis of bovine adipocytes were differentially affected by long-chain FA, with unsaturated FA more effective than saturated FA.

[Homozygous ectonucleotide pyrophosphatase/phosphodiesterase 1 variants in a girl with hypophosphatemic rickets and literature review]

Objective: To investigate the clinical features and genetic characteristics of patients with ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene variants. Method: The clinical data of a patient with ENPP1 homozygous variants from Capital Institute of Pediatrics was collected, the related literature was searched from China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, National Center from Biotechnology Information and PubMed by using search term "ENPP1" , "hypophosphatemic rickets" . The literature retrieval was confined from 1980 to February 2017. The clinical manifestations, bone metabolism examinations, X-RAY and genotypes were reviewed. Result: Our patient was an 11 years old girl, with 7 years history of lower limb malformation. She showed significant valgus deformity of the knee (genu valgum). Metabolic examination revealed reduced level of plasma phosphate (0.86 mmol/L), a normal level of plasma calcium (2.30 mmol/L) and an elevated alkaline phosphatase level of 688 IU/L. The calcium-phosphorus product was 25.9. A homozygous nonsense variants of ENPP1 gene, c.783C>G (p.Tyr261X) in exon 7 was identified in the patient. Both parents were heterozygous carriers. Literature review identified 3 Chinese patients from one publication and 17 cases from twenty one publications around the world. None of the patients was found PHEX variants which is the most common variants among hypophosphatemic rickets patients. The disease onset age was 11 months to 10 years. Eight patients had short stature, five patients had the history of generalized arterial calcification of infancy. Four suffered from deafness, three showed localized calcifications of arteries, three patients manifested pseudoxanthoma elasticum and two suffered from ossification of posterior longitudinal ligament. Nine missense variants, six splicing variants and 4 nonsense variants were reported among these twenty patients. c.783C>G was found in two Chinese patients. Conclusion: ENPP1 gene mutation was a cause of patient with hypophosphatemic rickets. Comorbid features included generalized arterial calcification of infancy, early onset hearing loss, pseudoxanthoma and ossification of posterior longitudinal ligament. ENPP1 gene testing should be performed on hypophosphatemic rickets patients without PHEX gene variants. Long-term follow up is recommended. The most common types of ENPP1 gene variants were nonsense/splicing variants. The gene c.783C>G was the most common variants in Chinese patients.

MYC2 Orchestrates a Hierarchical Transcriptional Cascade That Regulates Jasmonate-Mediated Plant Immunity in Tomato

The hormone jasmonate (JA), which functions in plant immunity, regulates resistance to pathogen infection and insect attack through triggering genome-wide transcriptional reprogramming in plants. We show that the basic helix-loop-helix transcription factor (TF) MYC2 in tomato (Solanum lycopersicum) acts downstream of the JA receptor to orchestrate JA-mediated activation of both the wounding and pathogen responses. Using chromatin immunoprecipitation sequencing (ChIP-seq) coupled with RNA sequencing (RNA-seq) assays, we identified 655 MYC2-targeted JA-responsive genes. These genes are highly enriched in Gene Ontology categories related to TFs and the early response to JA, indicating that MYC2 functions at a high hierarchical level to regulate JA-mediated gene transcription. We also identified a group of MYC2-targeted TFs (MTFs) that may directly regulate the JA-induced transcription of late defense genes. Our findings suggest that MYC2 and its downstream MTFs form a hierarchical transcriptional cascade during JA-mediated plant immunity that initiates and amplifies transcriptional output. As proof of concept, we showed that during plant resistance to the necrotrophic pathogen Botrytis cinerea, MYC2 and the MTF JA2-Like form a transcription module that preferentially regulates wounding-responsive genes, whereas MYC2 and the MTF ETHYLENE RESPONSE FACTOR.C3 form a transcription module that preferentially regulates pathogen-responsive genes.