Conserved pleiotropy of an ancient plant homeobox gene uncovered by cis-regulatory dissection.

Divergence of gene function is a hallmark of evolution, but assessing functional divergence over deep time is not trivial. The few alleles available for cross-species studies often fail to expose the entire functional spectrum of genes, potentially obscuring deeply conserved pleiotropic roles. Here, we explore the functional divergence of WUSCHEL HOMEOBOX9 (WOX9), suggested to have species-specific roles in embryo and inflorescence development. Using a cis-regulatory editing drive system, we generate a comprehensive allelic series in tomato, which revealed hidden pleiotropic roles for WOX9. Analysis of accessible chromatin and conserved cis-regulatory sequences identifies the regions responsible for this pleiotropic activity, the functions of which are conserved in groundcherry, a tomato relative. Mimicking these alleles in Arabidopsis, distantly related to tomato and groundcherry, reveals new inflorescence phenotypes, exposing a deeply conserved pleiotropy. We suggest that targeted cis-regulatory mutations can uncover conserved gene functions and reduce undesirable effects in crop improvement.

Mitochondrial Dysfunction Secondary to Endoplasmic Reticulum Stress in Acute Myocardial Ischemic Injury in Rats.

BACKGROUND The relationship between endoplasmic reticulum and mitochondria during acute myocardial ischemic injury is still unclear. Our study aimed to define the dynamics of endoplasmic reticulum stress and mitochondrial dysfunction during acute ischemic injury. MATERIAL AND METHODS A rat model of acute myocardial infarction and hypoxic cardiomyocytes were used in this study. Groups were set at 0 hours, 1 hour, 2 hours, 4 hours, and 6 hours after ischemic injury for both in vivo and in vitro studies. ATF6 and GRP-78 were examined to indicate endoplasmic reticulum stress. Cellular ATP and cytosolic levels of mitochondrial DNA and cytochrome c were detected to evaluate mitochondrial dysfunction. Caspase-3 was used for apoptosis analysis. RESULTS Our results showed that both mRNA and protein levels of ATF6 and GRP-78 were elevated from 1 hour after ischemic injury in vivo and in vitro (P<0.05). However, ATP levels were increased at 2 hours after ischemic injury and significantly decreased from 4 hours after ischemic injury in vivo, while ATP level of cultured cardiomyocytes decreased remarkably from 2 hours after ischemic injury (P<0.05). Cytosolic mitochondrial DNA levels began to increase from 2 hours after ischemic injury (P<0.05). Cytosolic levels of cytochrome c increased from 4 hours after ischemic injury. Additionally, both mRNA and protein expressions of caspase-3 started to significantly elevate at 6 hours after ischemic injury (P<0.05). CONCLUSIONS The present study suggested that mitochondrial dysfunction was secondary to endoplasmic reticulum stress, which provides a novel experimental foundation for further exploration of the detailed mechanism after ischemic injury, especially the interaction between endoplasmic reticulum and mitochondria.

A right ventricular mass in a young man with Behçet's disease: A case report.

Behçet's disease (BD) is a rarely seen immune disease with multiple systems involvements. Among them, a cardiac manifestation is a severe and rare complication of BD. Here we reported a young man with BD, complicated with a right ventricular thrombus. Surgery was performed successfully to remove the intracardiac thrombus, and a 2-year follow-up failed to find any new symptoms and pathological findings. Our experience provided a better example for diagnosing and early surgical treatment for intracardiac thrombus of BD.

Performance Improvement of Discretely Modulated Continuous-Variable Quantum Key Distribution with Untrusted Source via Heralded Hybrid Linear Amplifier.

In practical quantum communication networks, the scheme of continuous-variable quantum key distribution (CVQKD) faces a challenge that the entangled source is controlled by a malicious eavesdropper, and although it still can generate a positive key rate and security, its performance needs to be improved, especially in secret key rate and maximum transmission distance. In this paper, we proposed a method based on the four-state discrete modulation and a heralded hybrid linear amplifier to enhance the performance of CVQKD where the entangled source originates from malicious eavesdropper. The four-state CVQKD encodes information by nonorthogonal coherent states in phase space. It has better transmission distance than Gaussian modulation counterpart, especially at low signal-to-noise ratio (SNR). Moreover, the hybrid linear amplifier concatenates a deterministic linear amplifier (DLA) and a noiseless linear amplifier (NLA), which can improve the probability of amplification success and reduce the noise penalty caused by the measurement. Furthermore, the hybrid linear amplifier can raise the SNR of CVQKD and tune between two types of performance for high-gain mode and high noise-reduction mode, therefore it can extend the maximal transmission distance while the entangled source is untrusted.

CYCP2;1 integrates genetic and nutritional information to promote meristem cell division in Arabidopsis.

In higher plants, cell cycle activation in the meristems at germination is essential for the initiation of post-embryonic development. We previously identified the signaling pathways of homeobox transcription factor STIMPY and metabolic sugars as two interacting branches of the regulatory network that is responsible for activating meristematic tissue proliferation in Arabidopsis. In this study, we found that CYCP2;1 is both a direct target of STIMPY transcriptional activation and an early responder to sugar signals. Genetic and molecular studies show that CYCP2;1 physically interacts with three of the five mitotic CDKs in Arabidopsis, and is required for the G2 to M transition during meristem activation. Taken together, our results suggest that CYCP2;1 acts as a permissive control of cell cycle progression during seedling establishment by directly linking genetic control and nutritional cues with the activity of the core cell cycle machinery.

ELONGATA3 is required for shoot meristem cell cycle progression in Arabidopsis thaliana seedlings.

A key feature of the development of a higher plant is the continuous formation of new organs from the meristems. Originally patterned during embryogenesis, the meristems must activate cell division de novo at the time of germination, in order to initiate post-embryonic development. In a mutagenesis screen aimed at finding new players in early seedling cell division control, we identified ELONGATA3 (ELO3) as a key regulator of meristem cell cycle activation in Arabidopsis. Our results show that plants carrying a hypomorphic allele of ELO3 fail to activate cell division in the meristems following germination, which leads to seedling growth arrest and lethality. Further analyses suggest that this is due to a failure in DNA replication, followed by cell cycle arrest, in the meristematic tissue. Interestingly, the meristem cell cycle arrest in elo3 mutants, but not the later leaf developmental defects that have been linked to the loss of ELO3 activities, can be relieved by the addition of metabolic sugars in the growth medium. This finding points to a new role by which carbohydrate availability promotes meristem growth. Furthermore, growth arrested elo3 mutants suffer a partial loss of shoot meristem identity, which provides further evidence that cell cycle activities can influence the control of tissue identity.

WOX2 and STIMPY-LIKE/WOX8 promote cotyledon boundary formation in Arabidopsis.

One of the key events in dicot plant embryogenesis is the emergence of the two cotyledon primordia, which marks the transition from radial symmetry to bilateral symmetry. In Arabidopsis thaliana, the three CUP-SHAPED COTYLEDON (CUC) genes are responsible for determining the boundary region between the cotyledons. However, the mechanisms controlling their transcription activation are not well understood. Previous studies found that several WOX family homeobox transcription factors are involved in embryo apical patterning and cotyledon development. Here we show that WOX2 and STIMPY-LIKE (STPL/WOX8) act redundantly to differentially regulate the expression of the CUC genes in promoting the establishment of the cotyledon boundary, without affecting the primary shoot meristem. Loss of both WOX2 and STPL results in reduced CUC2 and CUC3 expression in one side of the embryo, but an expansion of the CUC1 domain. Furthermore, we found that STPL is expressed in the embryo proper, and its activation is enhanced by the removal of WOX2, providing an explanation for the functional redundancy between WOX2 and STPL. Additional evidence also showed that WOX2 and STPL function independently in regulating different aspects of local auxin gradient formation during early embryogenesis.

STIMPY mediates cytokinin signaling during shoot meristem establishment in Arabidopsis seedlings.

The establishment of the primary meristems through proliferation after germination is essential for plant post-embryonic development. Cytokinins have long been considered a key regulator of plant cell division. Here we show that cytokinins are essential for early seedling development of Arabidopsis. Loss of cytokinin perception leads to a complete failure of meristem establishment and growth arrest after germination. We also present evidence that cytokinin signaling is involved in activation of the homeobox gene STIMPY (STIP or WOX9) expression in meristematic tissues, which is essential for maintaining the meristematic fate. Cytokinin-independent STIP expression is able to partially compensate for the shoot apical meristem growth defects in mutants that cannot sense cytokinin. These findings identify a new branch of the cytokinin signaling network, linking cytokinin to the process of meristem and seedling establishment.

Metabolic sugar signal promotes Arabidopsis meristematic proliferation via G2.

Most organs in higher plants are generated postembryonically from the meristems, which harbor continuously dividing stem cells throughout a plant's life cycle. In addition to developmental regulations, mitotic activities in the meristematic tissues are modulated by nutritional cues, including carbon source availability. Here we further analyze the relationship between the sugar signal and seedling meristem establishment, taking advantage of our previous observation that exogenously supplied metabolic sugars can rescue the meristem growth arrest phenotype of the Arabidopsis stip mutant seedlings. Our results show that metabolic sugars reactivate the stip meristems by activating the expression of key cell cycle regulators, and therefore, promoting G2 to M transition in Arabidopsis meristematic tissues. One of the early events in this process is the transcriptional repression of TSS, a genetic suppressor of the stip mutations, by sugar signals, suggesting that TSS may act as an integrator of developmental and nutritional signals in regulating meristematic proliferation. We also present evidence that metabolic sugar signals are required for the activation of mitotic entry during de novo meristem formation from G2 arrested cells. Our observations, together with the recent findings that nutrient deprivation leads to G2 arrest of animal germline stem cells, suggest that carbohydrate availability-regulated G2 to M transition may represent a common mechanism in stem cell division regulation in multicellular organisms.

AGAMOUS-LIKE 6 is a floral promoter that negatively regulates the FLC/MAF clade genes and positively regulates FT in Arabidopsis.

MADS-box genes encode a family of transcription factors that regulate diverse developmental programs in plants. The present work shows the regulation of flowering time by AGL6 through control of the transcription of both a subset of the FLOWERING LOCUS C (FLC) family genes and FT, two key regulators of flowering time. The agl6-1D mutant, in which AGL6 was activated by the 35S enhancer, showed an early flowering phenotype under both LD and SD conditions. Its early flowering was additively accelerated by CONSTANS (CO) overexpression. The agl6-1D mutation strongly suppressed the late flowering of fve-4 and fca-9 mutants. Endogenous AGL6 transcript accumulation was photoperiod-independent and the AGL6:GFP protein was preferentially localized in the nucleus. In agl6-1D plants, the expression of FLC, MADS AFFECTING FLOWERING (MAF) 4, and MAF5 was downregulated. Interestingly, late flowering of a functional FRIGIDA (FRI) FLC allele was dramatically suppressed by the agl6-1D mutation. AGL6 activation in the flc-3 background further enhanced FT expression, suggesting that AGL6 also regulates FT expression independently of FLC mRNA level. A near RNA-null ft-10 mutation completely suppressed early flowering of the agl6-1D plants, suggesting that FT is a major downstream output of AGL6. Transgenic plants overexpressing an artificial microRNA targeting AGL6 showed a late-flowering phenotype. In these plants, FT expression was downregulated, whereas FLC expression was upregulated. The present results suggest that AGL6 acts as a floral promoter with a dual role, the inhibition of the transcription of the FLC/MAF genes and the promotion of FT expression in Arabidopsis.

Photodynamic Therapy for the Treatment of Fungal Infections.

Cutaneous fungal infections are common in humans and are associated with significant physical and psychological distress to patients. Although conventional topical and/or oral anti-fungal medications are commonly recommended treatments, drug resistance has emerged as a significant concern in this patient population, and safer, more efficacious, and cost-effective alternatives are warranted. Recent studies have reported effectiveness of photodynamic therapy (PDT) against fungal infections without severe adverse effects. In this review, we briefly discuss the mechanisms underlying PDT, current progress, adverse effects, and limitations of this treatment in the management of superficial and deep fungal infections.

A Retrospective Study of Clinical Efficacy of Cantharidin Cream for Verruca Plantaris.

Verruca plantaris (plantar wart) is a type of benign feet hyperplasia that is caused by a human papillomavirus (HPV) infection. In this study, we aimed to assess the clinical efficacy underlying cantharidin cream in the treatment of Verruca plantaris compared to CO2 laser and liquid nitrogen cryotherapy. One hundred and fifty patients affected with Verruca plantaris were enrolled in this retrospective clinical study. The treatment efficacy rate in the three groups was assessed 4 and 12 weeks after treatment. After 4 weeks of treatment, 46 cases in the externally applied cantharidin cream therapy group were cured with an apparent efficiency of 92.0% (46/50). Contrarily, 42 cases in the CO2 laser group were cured with 84.0% (42/50) efficiency, while 40 cases in the liquid nitrogen cryotherapy group were cured with an apparent efficiency of 80.0% (40/50). Although the clinical cure rate of Verruca plantaris in the Cantharidin group was greater than in the CO2 laser group and in the liquid nitrogen cryotherapy group, there were no statistical differences found among the three groups (P = 0.225). After 12 weeks of treatment, 43 cases in the external cantharidin cream therapy group were cured with an apparent efficiency of 86.0% (43/50). Similarly, 39 cases in the CO2 laser group were cured with an apparent efficiency of 78.0% (39/50), while 36 cases in the liquid nitrogen cryotherapy group were cured with an apparent efficiency of 72.0% (36/50). The statistical differences among the three groups were not found (P =0.230), but the resolution rate of warts in Cantharidin group was the highest among the three groups. The results from this study demonstrated that external cantharidin cream therapy could be served as an alternative treatment for Verruca plantaris.

Regulation of meristem size by cytokinin signaling.

The plant meristems possess unique features that involve maintaining the stem cell populations while providing cells for continued development. Although both the primary shoot apical meristem (SAM) and the root apical meristem (RAM) are specified during embryogenesis, post-embryonic tissue proliferation is required for their full establishment and maintenance throughout a plants' life. The phytohormone cytokinin (CK) interacts with other systemic signals and is a key regulator of meristem size and functions. The SAM and the RAM respond to CK stimulations in different manners: CK promotes tissue proliferation in the SAM through pathways dominated by homeobox transcription factors, including the class I KNOX genes, STIP, and WUS; and curiously, it favors proliferation at low levels and differentiation at a slightly higher concentration in the RAM instead. Here we review the current understanding of the molecular mechanisms underlying CK actions in regulating meristematic tissue proliferation.

Control of leaf morphogenesis by microRNAs.

Plants with altered microRNA metabolism have pleiotropic developmental defects, but direct evidence for microRNAs regulating specific aspects of plant morphogenesis has been lacking. In a genetic screen, we identified the JAW locus, which produces a microRNA that can guide messenger RNA cleavage of several TCP genes controlling leaf development. MicroRNA-guided cleavage of TCP4 mRNA is necessary to prevent aberrant activity of the TCP4 gene expressed from its native promoter. In addition, overexpression of wild-type and microRNA-resistant TCP variants demonstrates that mRNA cleavage is largely sufficient to restrict TCP function to its normal domain of activity. TCP genes with microRNA target sequences are found in a wide range of species, indicating that microRNA-mediated control of leaf morphogenesis is conserved in plants with very different leaf forms.

A self-organizing system of repressor gradients establishes segmental complexity in Drosophila.

Gradients of regulatory factors are essential for establishing precise patterns of gene expression during development; however, it is not clear how patterning information in multiple gradients is integrated to generate complex body plans. Here we show that opposing gradients of two Drosophila transcriptional repressors, Hunchback (Hb) and Knirps (Kni), position several segments by differentially repressing two distinct regulatory regions (enhancers) of the pair-rule gene even-skipped (eve). Computational and in vivo analyses suggest that enhancer sensitivity to repression is controlled by the number and affinity of repressor-binding sites. Because the kni expression domain is positioned between two gradients of Hb, each enhancer directs expression of a pair of symmetrical stripes, one on each side of the kni domain. Thus, only two enhancers are required for the precise positioning of eight stripe borders (four stripes), or more than half of the whole eve pattern. Our results show that complex developmental expression patterns can be generated by simple repressor gradients. They also support the utility of computational analyses for defining and deciphering regulatory information contained in genomic DNA.

Requirement of homeobox gene STIMPY/WOX9 for Arabidopsis meristem growth and maintenance.

Most organs of flowering plants develop postembryonically from groups of pluripotent cells called meristems [1]. The shoot apical meristem (SAM) is specified by two complementary pathways [2-4]. SHOOT MERISTEMLESS (STM; [5]) defines the entire SAM region [6]. WUSCHEL (WUS), on the other hand, functions in a more restricted set of cells to promote stem-cell fate and is regulated by the CLAVATA genes in a negative feedback loop [7-10]. In contrast, little is known about how the growth of the SAM, which increases in size during vegetative development [11], is regulated. We have characterized STIMPY (STIP; also called WOX9 [12]), a homeobox gene required for the growth of the vegetative SAM, in part by positively regulating WUS expression. In addition, STIP is required in several other aerial organs and the root. What sets STIP apart from STM and WUS is that stip mutants can be fully rescued by stimulating the entry into the cell cycle with sucrose. Therefore, STIP is likely to act in all these tissues by maintaining cell division and preventing premature differentiation. Taken together, our findings suggest that STIP identifies a new genetic pathway integrating developmental signals with cell-cycle control.

Macrophage polarization, inflammatory signaling, and NF-κB activation in response to chemically modified titanium surfaces.

Functionalization of titanium devices with various bioactive molecules enhances many of their properties as implants, including biocompatibility, which is typically assessed by macrophage activation and inflammation. However, functionalization requires prior introduction of reactive groups, to which bioactive agents can then be grafted. Thus, we investigated the inflammatory properties of titanium pretreated with NaOH, titanium pretreated with NaOH and then with 3-aminopropyl triethoxysilane, and titanium pretreated with dopamine. Inflammation, macrophage polarization, and activation of NF-κB signaling were assessed by real-time PCR and western blotting. The data demonstrate that silanized titanium is the least inflammatory, and promotes macrophage M2 polarization with modest engagement of the NF-κB signaling pathway. Importantly, silanization introduces a reactive amino group, providing more opportunities for further functionalization.

A new less invasive surgical technique in the management of acute Achilles tendon rupture through limited-open procedure combined with a single-anchor and "circuit" suture technique.

BACKGROUND: Traditional incision repair and minimally invasive repair for acute Achilles tendon repair have limitations. This study aimed to present our series of 23 patients with acute Achilles tendon rupture that was repaired using two small incisions to assist the anchor repair of the tear and a new "circuit" suture technique. METHODS: This was a retrospective study of 23 patients with acute Achilles tendon rupture treated with the new technique at Changhai Hospital between January 2015 and December 2016 and followed up for 14-33 months. Clinical outcome was assessed using the AOFAS, Leppilahti, and Arner-Lindholm scores. Complications, range of motion (ROM), and time to return to work and light sport activity were assessed. RESULTS: The AOFAS score was 85-96 at 3 months and 92-100 at 12 months. The 3-month ROM was 27°-37°, and the 12-month ROM was 36°-48°. The Leppilahti score was 85-95 at 3 months and 90-100 at 12 months. The recovery time of the patients was 10-18 weeks. The postoperative recovery time to exercise was 16-24 weeks. There was only one case of deep venous thrombosis. According to the Arner-Lindholm assessment criteria, patient outcomes were rated as excellent in 20 (87.0%) cases, good in three (13.0%) cases, and poor in 0 cases. The excellent-to-good rate was 100%. CONCLUSION: The limited-open procedure combined with a single-anchor and "circuit" suture technique could be used to repair torn Achilles sites, with a low occurrence of complications. This new and minimally invasive technique could be an alternative in the management of acute Achilles tendon rupture.

STIMPY mutants have increased cytokinin sensitivity during dark germination.

The cytokinins regulate a broad range of plant developmental events. We recently reported that the homeodomain transcription factor STIMPY (STIP) positively mediates the cytokinin signals in maintaining proliferative and pluoripotent properties of the shoot apical meristem in Arabidopsis. In line with our proposed model, light-grown stip seedlings are less sensitive to the growth inhibition effect of the exogenously applied cytokinins than wild type. Here we investigate STIP's role in cytokinin signaling in dark-grown seedlings, in which elevated cytokinin levels promote photomorphogenesis. We found that stip mutants show enhanced deetiolation phenotype in response to cytokinin treatment in the dark, suggesting that STIP may be a negative regulator of cytokinin signaling under this condition. We discuss possible explanations for this observed developmental stage-specific function of STIP.