Hexose translocation mediated by SlSWEET5b is required for pollen maturation in Solanum lycopersicum

Pollen fertility is critical for successful fertilization and, accordingly, for crop yield. While sugar unloading affects the growth and development of all types of sink organs, the molecular nature of sugar import to tomato (Solanum lycopersicum) pollen is poorly understood. However, sugar will eventually be exported transporters (SWEETs) have been proposed to be involved in pollen development. Here, reverse transcription-quantitative polymerase chain reaction (PCR) revealed that SlSWEET5b was markedly expressed in flowers when compared to the remaining tomato SlSWEETs, particularly in the stamens of maturing flower buds undergoing mitosis. Distinct accumulation of SlSWEET5b-β-glucuronidase activities was present in mature flower buds, especially in anther vascular and inner cells, symplasmic isolated microspores (pollen grains), and styles. The demonstration that SlSWEET5b-GFP fusion proteins are located in the plasma membrane supports the idea that the SlSWEET5b carrier functions in apoplasmic sugar translocation during pollen maturation. This is consistent with data from yeast complementation experiments and radiotracer uptake, showing that SlSWEET5b operates as a low-affinity hexose-specific passive facilitator, with a Km of ∼36 mM. Most importantly, RNAi-mediated suppression of SlSWEET5b expression resulted in shrunken nucleus-less pollen cells, impaired germination, and low seed yield. Moreover, stamens from SlSWEET5b-silenced tomato mutants showed significantly lower amounts of sucrose (Suc) and increased invertase activity, indicating reduced carbon supply and perturbed Suc homeostasis in these tissues. Taken together, our findings reveal the essential role of SlSWEET5b in mediating apoplasmic hexose import into phloem unloading cells and into developing pollen cells to support pollen mitosis and maturation in tomato flowers.

Transporter SlSWEET15 unloads sucrose from phloem and seed coat for fruit and seed development in tomato

Tomato (Solanum lycopersium), an important fruit crop worldwide, requires efficient sugar allocation for fruit development. However, molecular mechanisms for sugar import to fruits remain poorly understood. Expression of sugars will eventually be exported transporters (SWEETs) proteins is closely linked to high fructose/glucose ratios in tomato fruits and may be involved in sugar allocation. Here, we discovered that SlSWEET15 is highly expressed in developing fruits compared to vegetative organs. In situ hybridization and β-glucuronidase fusion analyses revealed SlSWEET15 proteins accumulate in vascular tissues and seed coats, major sites of sucrose unloading in fruits. Localizing SlSWEET15-green fluorescent protein to the plasma membrane supported its putative role in apoplasmic sucrose unloading. The sucrose transport activity of SlSWEET15 was confirmed by complementary growth assays in a yeast (Saccharomyces cerevisiae) mutant. Elimination of SlSWEET15 function by clustered regularly interspaced short palindromic repeats (CRISPRs)/CRISPR-associated protein gene editing significantly decreased average sizes and weights of fruits, with severe defects in seed filling and embryo development. Altogether, our studies suggest a role of SlSWEET15 in mediating sucrose efflux from the releasing phloem cells to the fruit apoplasm and subsequent import into storage parenchyma cells during fruit development. Furthermore, SlSWEET15-mediated sucrose efflux is likely required for sucrose unloading from the seed coat to the developing embryo.

GeSUT4 mediates sucrose import at the symbiotic interface for carbon allocation of heterotrophic Gastrodia elata (Orchidaceae)

Gastrodia elata, a fully mycoheterotrophic orchid without photosynthetic ability, only grows symbiotically with the fungus Armillaria. The mechanism of carbon distribution in this mycoheterotrophy is unknown. We detected high sucrose concentrations in all stages of Gastrodia tubers, suggesting sucrose may be the major sugar transported between fungus and orchid. Thick symplasm-isolated wall interfaces in colonized and adjacent large cells implied involvement of sucrose importers. Two sucrose transporter (SUT)-like genes, GeSUT4 and GeSUT3, were identified that were highly expressed in young Armillaria-colonized tubers. Yeast complementation and isotope tracer experiments confirmed that GeSUT4 functioned as a high-affinity sucrose-specific proton-dependent importer. Plasma-membrane/tonoplast localization of GeSUT4-GFP fusions and high RNA expression of GeSUT4 in symbiotic and large cells indicated that GeSUT4 likely functions in active sucrose transport for intercellular allocation and intracellular homeostasis. Transgenic Arabidopsis overexpressing GeSUT4 had larger leaves but were sensitive to excess sucrose and roots were colonized with fewer mutualistic Bacillus, supporting the role of GeSUT4 in regulating sugar allocation. This is not only the first documented carbon import system in a mycoheterotrophic interaction but also highlights the evolutionary importance of sucrose transporters for regulation of carbon flow in all types of plant-microbe interactions.

Co-Delivery of Natural Compounds with a Dual-Targeted Nanoparticle Delivery System for Improving Synergistic Therapy in an Orthotopic Tumor Model

Various natural compounds including epigallocatechin gallate (EGCG) and curcumin (CU) have potential in developing anticancer therapy. However, their clinical use is commonly limited by instability and low tissue distribution. EGCG and CU combined treatment can improve the efficacy with synergistic effects. To improve the synergistic effect and overcome the limitations of low tissue distribution, we applied a dual cancer-targeted nanoparticle system to co-deliver EGCG and CU. Nanoparticles were composed of hyaluronic acid, fucoidan, and poly(ethylene glycol)-gelatin to encapsulate EGCG and CU. Furthermore, a dual targeting system was established with hyaluronic acid and fucoidan, which were used as agents for targeting CD44 on prostate cancer cells and P-selectin in tumor vasculature, respectively. Their effect and efficacy were investigated in prostate cancer cells and a orthotopic prostate tumor model. The EGCG/CU-loaded nanoparticles bound to prostate cancer cells, which were uptaken more into cells, leading to a better anticancer efficiency compared to the EGCG/CU combination solution. In addition, the releases of EGCG and CU were regulated by their pH value that avoided the premature release. In mice, treatment of the cancer-targeted EGCG/CU-loaded nanoparticles significantly attenuated the orthotopic tumor growth without inducing organ injuries. Overall, the dual-targeted nanoparticle system for the co-delivery of EGCG and CU greatly improved its synergistic effect in cancer therapy, indicating its great potential in developing treatments for prostate cancer therapy.

SlSWEET1a is involved in glucose import to young leaves in tomato plants

Sugar allocation from source to sink (young) leaves, critical for plant development, relies on activities of plasma membrane sugar transporters. However, the key sugar unloading mechanism to sink leaves remains elusive. SWEET transporters mediate sugar efflux into reproductive sinks; therefore, they are promising candidates for sugar unloading during leaf growth. Transcripts of SlSWEET1a, belonging to clade I of the SWEET family, were markedly more abundant than those of all other 30 SlSWEET genes in young leaves of tomatoes. High expression of SlSWEET1a was also detected in reproductive sinks, such as flowers. SlSWEET1a was dominantly expressed in leaf unloading veins, and the green fluorescent protein (GFP) fusion protein was localized to the plasma membrane using Arabidopsis protoplasts, further implicating this carrier in sugar unloading. In addition, yeast growth assays and radiotracer uptake analyses further demonstrated that SlSWEET1a acted as a low-affinity (Km ~100 mM) glucose-specific carrier with a passive diffusion manner. Finally, virus-induced gene silencing of SlSWEET1a expression reduced hexose accumulation to ~50% in young leaves, with a parallel 2-fold increase in mature leaves. Thus, we propose a novel function for SlSWEET1a in the uptake of glucose into unloading cells as part of the sugar unloading mechanism in sink leaves of tomato.

Polymorphisms in the promoter regions of the CXCL1 and CXCL2 genes contribute to increased risk of alopecia areata in the Korean population

Alopecia areata (AA) is a common disease, which causes hair loss in humans. AA has a genetically complex inheritance. This study investigated the possible correlations between single nucleotide polymorphisms (SNPs) in the promoter regions of the chemokine (C-X-C motif) ligand 1 (melanoma growth stimulating activity, alpha) (CXCL1) and chemokine (C-X-C motif) ligand 2 (CXCL2) genes and the development of AA in the Korean population. Two hundred and thirty-five AA patients and 240 control subjects were recruited. The specific SNPs occurring in the promoter regions of the CXCL1 and CXCL2 genes (rs3117604, -429C/T and rs3806792, -264T/C, respectively) were genotyped. All data obtained was evaluated using the SNPStats, SPSS 18.0, and the Haploview v.4.2 software platforms. The Odd's ratios (OR), 95% confidence intervals (CI), and P values were calculated using multiple logistic regression models. Analyses of the genetic sequences obtained revealed a significant correlation between the two SNPs and the development of AA (rs3117604, P = 0.0009 in co-dominant model 1, P = 0.01 in co-dominant model 2, P = 0.004 in the dominant model, P = 0.005 in the log-additive model, P = 0.012 in allele distribution; rs3806792, P = 0.036 in co-dominant model 2, P = 0.0046 in the log-additive model). The TT and CC haplotypes were also observed to show a significant association with increased risk of AA (TT haplotype, P = 0.0018; CC haplotype, P = 0.0349). Our data suggests that the CXCL1 and CXCL2 genes may be associated with AA susceptibility.

The novel miR-9500 regulates the proliferation and migration of human lung cancer cells by targeting Akt1

MicroRNAs have crucial roles in lung cancer cell development. They regulate cell growth, proliferation and migration by mediating the expression of tumor suppressor genes and oncogenes. We identified and characterized the novel miR-9500 in human lung cancer cells. The miR-9500 forms a stem-loop structure and is conserved in other mammals. The expression levels of miR-9500 were reduced in lung cancer cells and lung cancer tissues compared with normal tissues, as verified by TaqMan miRNA assays. It was confirmed that the putative target gene, Akt1, was directly suppressed by miR-9500, as demonstrated by a luciferase reporter assay. The miR-9500 significantly repressed the protein expression levels of Akt1, as demonstrated via western blot, but did not affect the corresponding mRNA levels. Akt1 has an important role in lung carcinogenesis, and depletion of Akt1 has been shown to have antiproliferative and anti-migratory effects in previous studies. In the current study, the overexpression of miR-9500 inhibited cell proliferation and the expression of cell cycle-related proteins. Likewise, the overexpression of miR-9500 impeded cell migration in human lung cancer cells. In an in vivo assay, miR-9500 significantly suppressed Fluc expression compared with NC and ASO-miR-9500, suggesting that cell proliferation was inhibited in nude mice. Likewise, miR-9500 repressed tumorigenesis and metastasis by targeting Akt1. These data indicate that miR-9500 might be applicable for lung cancer therapy.

Walking index for spinal cord injury (WISCI): an international multicenter validity and reliability study

STUDY DESIGN

Construction of an international walking scale by a modified Delphi technique.

OBJECTIVE

The purpose of the study was to develop a more precise walking scale for use in clinical trials of subjects with spinal cord injury (SCI) and to determine its validity and reliability.

SETTING

Eight SCI centers in Australia, Brazil, Canada (2), Korea, Italy, the UK and the US.

METHODS

Original items were constructed by experts at two SCI centers (Italy and the US) and blindly ranked in an hierarchical order (pilot data). These items were compared to the Functional Independence Measure (FIM) for concurrent validity. Subsequent independent blind rank ordering of items was completed at all eight centers (24 individuals and eight teams). Final consensus on rank ordering was reached during an international meeting (face validation). A videotape comprised of 40 clips of patients walking was forwarded to all eight centers and inter-rater reliability data collected.

RESULTS

Kendall coefficient of concordance for the pilot data was significant (W=0. 843, P<0.001) indicating agreement among the experts in rank ordering of original items. FIM comparison (Spearman's rank correlation coefficient=0.765, P<0.001) showed a theoretical relationship, however a practical difference in what is measured by each scale. Kendall coefficient of concordance for the international blind hierarchical ranking showed significance (W=0.860, P<0.001) indicating agreement in rank ordering across all eight centers. Group consensus meeting resulted in a 19 item hierarchical rank ordered 'Walking Index for Spinal Cord Injury (WISCI)'. Inter-rater reliability scoring of the 40 video clips showed 100% agreement.

CONCLUSIONS

This is the first time a walking scale for SCI of this complexity has been developed and judged by an international group of experts. The WISCI showed good validity and reliability, but needs to be assessed in clinical settings for responsiveness.

Electrophysiologic recovery after vitamin E-deficient neuropathy

A case report is presented of an electrophysiologic recovery from vitamin E-deficient neuropathy after treatment with water-soluble vitamin E in a patient with chronic hepatobiliary disease. The patient was a 64-year-old man who had experienced progressive difficulty in ambulation, with ataxia, over the previous 3 years. The symptoms were associated with pain, tingling sensation in the extremities, and reduced fine motor activity. The patient had chronic hepatobiliary disease, with recurrent cholangitis and external drainage of bile acid through a T-tube for more than 20 years. Vitamin E level was barely detectable (<0.5 mg/L). Sensory conduction was absent in both sural nerves. Other sensory and motor conduction studies in the upper and lower extremities showed decreased amplitude. The patient was treated with water-soluble vitamin E. After 4 months of therapy, his ambulation function improved, but pain and tingling sensation in both hands remained. Sensory nerve action potentials appeared in both sural nerves, and amplitudes of other sensory nerves were increased. In a second follow-up study after 9 months, all of the evaluated parameters in the nerve conduction studies, as well as the vitamin E level, were normal. The authors conclude that vitamin E-deficient neuropathy is reversible and electrophysiologic recovery can occur with water-soluble vitamin E therapy.

The pattern of reflex recovery during spinal shock

STUDY DESIGN

A prospective descriptive study of the course of recovery of reflexes following acute spinal cord injury (SCI).

OBJECTIVES

The purpose of the study was to observe the pattern of reflex recovery following acute SCI in order to determine the prognostic significance of reflexes for ambulation and their relationship to spinal shock.

SETTING

A regional spinal cord injury center in Philadelphia, Pennsylvania, USA.

METHODS

Fifty subjects admitted consecutively over a 9 month period and on the day of injury were observed for the following reflexes; bulbo-cavernosis (BC), delayed plantar response (DPR), cremasteric (CRM), ankle jerk (AJ), knee jerk (KJ), and normal plantar response for 5 7 days a week and 6-8 weeks duration. The 50 subjects were assessed for ambulation of 200 feet at time of discharge. MRI studies were reviewed on 13/28 complete (ASIA A) injuries.

RESULTS

Thirty-five subjects (28 ASIA A, 4 ASIA B, 3 ASIA C) had a DPR of 2 days or longer duration and these subjects were not ambulatory. The fourteen subjects (12 ASIA D and 2 ASIA C), who were ambulatory, either had no DPR (11/14) or had a DPR of only 1 days duration (3/14). One subject (ASIA B) was not ambulatory and had a DRP of 1 days duration. The DPR was the first reflex to recover most often, followed by the BC, CRM in the first few days and later followed by the deep tendon reflexes (AJ & KJ) by 1-2 weeks respectively. Less than 8% of subjects had no reflexes on the day of injury and the reflexes did not follow a caudal-rostral pattern of recovery.

CONCLUSIONS

Prognosis for ambulation based on reflexes early after SCI should not be linked to current descriptions of spinal shock. In fact, the view of spinal shock, based on the absence of reflexes and the recovery of reflexes in a caudal to rostral sequence, is of limited clinical utility and should be discarded. The evolution of reflexes over several days following injury may be more relevant to prognosis than the use of the term spinal shock and the presence or absence of reflexes on the day of injury.

Spinal cord injury secondary to cervical disc herniation in ambulatory patients with cerebral palsy

Early onset of degeneration of the cervical spine and instability due to sustained abnormal tonicity or abnormal movement of the neck are found in patients with cerebral palsy. An unexplained change or deterioration of neurological function in patients with cerebral palsy should merit the consideration of the possibility of cervical myelopathy due to early degeneration or instability of the cervical spine. We describe two patients who had a spinal cord injury due to a cervical disc herniation, one patient was athetoid and the second had spastic diplegia, they both had cerebral palsy. It is not easy to determine whether new neurological symptoms are as a result of the cervical spinal cord disorder. These cases suggest that consideration of a cervical spine disorder with myelopathy is required in the evaluation of patients with cerebral palsy who develop deterioration of neurological function or activities over a short period of time.

Facet tropism in lumbar motion segments and its significance in disc herniation

OBJECTIVE AND DESIGN

To define facet tropism (FT) for each motion segment of the lower lumbar spine for subjects without disc herniation, and to evaluate the significance of facet tropism in disc herniation.

METHODS

Sixty subjects were evaluated by measuring the facet angle (FA) of three lower lumbar motion segments with the use of computed tomography (CT) and a computer program. The subjects were divided into two groups: 33 without disc herniation and 27 with disc herniation at one or more levels of lower lumbar motion segments. The FA was defined as the angle of the facet and midsagittal lines. The difference between the right and left FAs at each motion segment was calculated. FT was defined as an angle difference larger than the mean and one standard deviation of the angle differences between the right and left FAs at each motion segment in the group without disc herniation.

OUTCOME MEASUREMENTS

Statistical significance of the bilateral angle difference of each lower lumbar motion segment between the two groups was analyzed by the two-sample t test. Using the defined angle difference for FT, the incidence of FT in the two groups at each motion segment was analyzed by the Fisher's exact test.

RESULTS

FT was defined for the 33 subjects without disc herniation on CT scans as an angle difference larger than 12 degrees at L3-L4, 15 degrees at L4-L5, and 12 degrees at L5-S1, approximately. There was no statistical significance in the bilateral FA difference (p > .05) and incidence of FT (p > .05) at each segment between the two groups.

CONCLUSION

This study did not show that facet joint tropism plays a significant role in disc herniation in the lower lumbar spine.

Treatment of external urethral sphincter hypertonicity by pudendal nerve block using phenol solution in patients with spinal cord injury

We report our experience utilizing the technique of phenol block of the pudendal nerve in the treatment of voiding dysfunction due to hypertonicity of the external urethral sphincter. We have performed 13 pudendal nerve blocks using a 7% phenol solution in seven patients with spinal cord injury who could not obtain relaxation of the external urethral sphincter with a large postvoid urine residual (150 ml to 600 ml) despite large doses of antispasticity drugs and intermittent catheterisations over three weeks. These drugs were discontinued at least 48 hours before this procedure. The efficacy of the pudendal nerve block could also be tested by the ease of facilitating micturition during or just after the block and measuring the amount of postvoid residual urine and intravesical leak pressure. A pudendal nerve block was produced by injecting a 7% phenol solution medial to the ischial tuberosity having specifically localized the nerve by electrical stimulation. This procedure improved the voiding pattern dramatically, leading to a full stream of urine and a remarkable decrease of postvoid residual volume and intravesical leak pressure. The mean difference of the postvoid residual volume and the intravesical leak pressure before and after pudendal nerve block was 255.7 ml and 57.5 cmH2O, respectively. We conclude that pudendal nerve block with a phenol solution as a treatment of external urethral sphincter hypertonicity was effective, easy to perform, and had no complication. This treatment should be considered as a possible alternative to more invasive surgical procedures.

Prognostic significance of the delayed plantar reflex following spinal cord injury

The delayed plantar reflex (DPR) is a pathologic flexor variant which requires unusually strong stimulation of the sole of the foot and is characterized by a prolonged interval between the stimulus and the response, slow and protracted plantarflexion of the great toe and/or other toes and slow return to the neutral position. The purpose of this study was to evaluate prospectively the functional outcome of spinal cord injury (SCI) patients based on the presence or absence of a DPR immediately following injury. Thirty-six subjects were evaluated within one week of injury. A complete neurological evaluation following American Spinal Injury Association (ASIA) standards was performed and the presence or absence of a DPR was noted on admission. Ambulation status and ASIA Impairment Scales were recorded at discharge from the rehabilitation unit and the data were analyzed by the Chi-square method with Yates' correction for continuity. The data demonstrated a high correlation of the DPR with motor complete injuries (p < 0.01) and a poor prognosis for recovery of ambulation (p < 0.01). Clinicians should recognize this abnormal reflex, which may be used in conjunction with a complete neurological examination, to help prognosticate future function in the acute SCI patient.

Surveyor v: lunar surface mechanical properties

The mechanical properties of the lunar soil at the Surveyor V landing site seem to be generally consistent with values determined for soils at the landing sites of Surveyor I and III. These three maria sites are hundreds of kilometers apart. However, the static bearing capability may be somewhat lower than that at the previous landing sites (2 x 10(5) to 6 x 10(5) dynes per square centimeter or 3 to 8 pounds per square inch). The results of the erosion experiment, the spacecraft landing effects, and other observations indicate that the soil has significant amounts of fine-grained material and a measurable cohesion.