Engineering Pseudomonas chlororaphis HT66 for the Biosynthesis of Copolymers Containing 3-Hydroxybutyrate and Medium-Chain-Length 3-Hydroxyalkanoates.

Polyhydroxyalkanoates (PHAs) are promising alternatives to petroleum-based plastics, owing to their biodegradability and superior material properties. Here, the controllable biosynthesis of scl-co-mcl PHA containing 3-hydroxybutyrate (3HB) and mcl 3-hydroxyalkanoates was achieved in Pseudomonas chlororaphis HT66. First, key genes involved in fatty acid ß-oxidation, the de novo fatty acid biosynthesis pathway, and the phaC1-phaZ-phaC2 operon were deleted to develop a chassis strain. Subsequently, an acetoacetyl-CoA reductase gene phaB and a PHA synthase gene phaC with broad substrate specificity were heterologously expressed for producing and polymerizing the 3HB monomer with mcl 3-hydroxyalkanoates under the assistance of native ß-ketothiolase gene phaA. Furthermore, the monomer composition of scl-co-mcl PHA was regulated by adjusting the amount of glucose and dodecanoic acid supplemented. Notably, the cell dry weight and scl-co-mcl PHA content reached 14.2 g/L and 60.1 wt %, respectively, when the engineered strain HT11Δ::phaCB was cultured in King's B medium containing 5 g/L glucose and 5 g/L dodecanoic acid. These results demonstrated that P. chlororaphis can be a platform for producing scl-co-mcl PHA and has the potential for industrial application.

Construction and Hierarchical Self-Assembly of a Supramolecular Metal-Carbene Complex with Multifunctional Units.

Hierarchical combinations involving metal-ligand interactions and host-guest interactions can consolidate building blocks with unique functions into material properties. This study reports the construction and hierarchical self-assembly of multifunctional trinuclear AuI tricarbene complex containing three crown ether units and three ferrocene units. Host-guest interactions between the multifunctional trinuclear AuI tricarbene complex and organic ammonium salts were investigated, revealing that crown ether-based host-guest interactions can effectively regulate the electrochemical properties of the complex. Utilizing bisammonium salt as the cross-linker and multifunctional trinuclear AuI tricarbene complex as the core, a stimuli-responsive and self-healing supramolecular gel with different functional units was obtained.

Construction and Hierarchical Self-Assembly of Multifunctional Coordination Cages with Triangular Metal-Metal-Bonded Units.

Herein, a series of face-capped (Tr2M3)4L4 (Tr = cycloheptatrienyl cationic ring; M = metal; L = organosulfur ligand) tetrahedral cages 1-3 functionalized with 12 appended crown ether moieties were designed and synthesized. The reversible binding of ammonium cations with peripheral crown ether moieties to adjust internal guest-binding was realized. Combination of a bisammonium linker and cage 3 led to the formation of a supramolecular gel SPN1 via host-guest interactions between the crown ether moieties and ammonium salts. The obtained supramolecular gel exhibited multiple-stimuli responsiveness, injectability, and excellent self-healing properties and could be further developed to a SPN1-based drug delivery system. In addition, the storage modulus of SPN1 was 20 times higher than that of the model gel without Pd-Pd bonded blocks, and SPN1 had better self-healing properties compared with the latter, demonstrating the importance of such cages in improving mechanical strength without losing the dynamic properties of the material. The cytotoxicity in vitro of the drug-loaded (doxorubicin or methotrexate) SPN1 was significantly improved compared to that of free drugs.

Transcription factors KNAT3 and KNAT4 are essential for integument and ovule formation in Arabidopsis.

Integuments form important protective cell layers surrounding the developing ovules in gymno- and angiosperms. Although several genes have been shown to influence the development of integuments, the transcriptional regulatory mechanism is still poorly understood. In this work, we report that the Class II KNOTTED1-LIKE HOMEOBOX (KNOX II) transcription factors KNOTTED1-LIKE HOMEBOX GENE 3 (KNAT3) and KNAT4 regulate integument development in Arabidopsis (Arabidopsis thaliana). KNAT3 and KNAT4 were co-expressed in inflorescences and especially in young developing ovules. The loss-of-function double mutant knat3 knat4 showed an infertility phenotype, in which both inner and outer integuments of the ovule are arrested at an early stage and form an amorphous structure as in the bell1 (bel1) mutant. The expression of chimeric KNAT3- and KNAT4-EAR motif repression domain (SRDX repressors) resulted in severe seed abortion. Protein-protein interaction assays demonstrated that KNAT3 and KNAT4 interact with each other and also with INNER NO OUTER (INO), a key transcription factor required for the outer integument formation. Transcriptome analysis showed that the expression of genes related with integument development is influenced in the knat3 knat4 mutant. The knat3 knat4 mutant also had a lower indole-3-acetic acid (IAA) content, and some auxin signaling pathway genes were downregulated. Moreover, transactivation analysis indicated that KNAT3/4 and INO activate the auxin signaling gene IAA INDUCIBLE 14 (IAA14). Taken together, our study identified KNAT3 and KNAT4 as key factors in integument development in Arabidopsis.

China rheumatoid arthritis registry of patients with Chinese medicine (CERTAIN): Rationale, design, and baseline characteristics of the first 11,764 enrollees.

BACKGROUND: Chinese medicine (CM) has become a popular interventional treatment for rheumatoid arthritis (RA). However, limited knowledge about general characteristics and long-term clinical outcomes hampers the development of CM for RA. PURPOSE: The main objectives of the China Rheumatoid Arthritis Registry of Patients with Chinese Medicine (CERTAIN) were to describe the population of RA patients receiving CM treatment in multiple centers in China using different variables and compare these findings with internationally reported data. STUDY DESIGN: The CERTAIN is a prospective, multicenter, observational disease registry. METHODS: Adult RA patients who fulfilled the 2010 American College of Rheumatology/ European League Against Rheumatism classification criteria for RA and received CM treatment were recruited into the CERTAIN by rheumatologists from 145 hospitals across 30 provinces in China. Data on demographics, disease characteristics, comorbidities, treatments, and adverse events, with a 2-year follow-up, were collected and documented using a predefined protocol. RESULTS: In the 2 years since the study began in September 2019, 11,764 patients have been enrolled (enrolment is ongoing), and 13.10% of participants have completed the 6-month follow-up. We present the baseline characteristics of the first 11,764 enrollees. CONCLUSIONS: The CERTAIN is the first nationwide registry to document comprehensive data on CM treatment in patients with RA. The development of the CERTAIN resource is a significant step forward for Chinese RA patients, herbal medicine users, and research communities and will deepen our understanding of CM for RA. REGISTRATION: The study was registered at ClinicalTrials.gov (NCT05219214).

Reduction of psychological cravings and anxiety in women compulsorily isolated for detoxification using autonomous sensory meridian response (ASMR).

OBJECTIVE: To explore the effects of the autonomous sensory meridian response (ASMR) on the psychological cravings and anxiety of women compulsorily isolated for detoxification. METHOD: Around 122 women were recruited in a female drug detoxification center. Except for the 12-week training of ASMR, the experimental conditions of the experimental group (n = 60) were the same as those of the control group (n = 62). The addiction Stroop task was used to assess the level of psychological cravings and the State-Trait Anxiety Inventory was used to assess the level of anxiety. RESULTS: After the training, the decrease in state anxiety of the experimental group was larger than that of the control group, and the reaction time of the experimental group in the Stroop was also significantly lower than before the training. CONCLUSIONS: ASMR could thus reduce to a certain extent the state anxiety and attentional bias for drug-related clues under signaling psychological cravings among women compulsorily isolated for detoxification. HIGHLIGHTS: Intervention effects on psychological cravings and anxiety of women isolated for detoxification Basis for role of ASMR in regulating psychological cravings and anxiety in forced abstainers ASMR intervention reduced forced abstainers' attentional bias to drug-related clues.

ACE2-independent infection of T lymphocytes by SARS-CoV-2.

SARS-CoV-2 induced marked lymphopenia in severe patients with COVID-19. However, whether lymphocytes are targets of viral infection is yet to be determined, although SARS-CoV-2 RNA or antigen has been identified in T cells from patients. Here, we confirmed that SARS-CoV-2 viral antigen could be detected in patient peripheral blood cells (PBCs) or postmortem lung T cells, and the infectious virus could also be detected from viral antigen-positive PBCs. We next prove that SARS-CoV-2 infects T lymphocytes, preferably activated CD4 + T cells in vitro. Upon infection, viral RNA, subgenomic RNA, viral protein or viral particle can be detected in the T cells. Furthermore, we show that the infection is spike-ACE2/TMPRSS2-independent through using ACE2 knockdown or receptor blocking experiments. Next, we demonstrate that viral antigen-positive T cells from patient undergone pronounced apoptosis. In vitro infection of T cells induced cell death that is likely in mitochondria ROS-HIF-1a-dependent pathways. Finally, we demonstrated that LFA-1, the protein exclusively expresses in multiple leukocytes, is more likely the entry molecule that mediated SARS-CoV-2 infection in T cells, compared to a list of other known receptors. Collectively, this work confirmed a SARS-CoV-2 infection of T cells, in a spike-ACE2-independent manner, which shed novel insights into the underlying mechanisms of SARS-CoV-2-induced lymphopenia in COVID-19 patients.

A qualitative exploration of "empathic labor" in Chinese hospice nurses.

BACKGROUND: Hospice nurses may devote more emotional labor during the empathy process with patients, and this empathy can be used as a form of psychological behavior of emotional labor in the hospice care model. The aim of this study was to analyze hospice nurses' empathy characteristics in the context of emotional labor theory, and explore the impact of empathy on patient care. METHODS: We conducted semi-participant observations from three hospitals and multicenter in-depth interviews with n = 26 hospice nurses from eight cities. Interviews were transcribed, and directed content analysis was applied. RESULTS: Two categories with four sub-categories were extracted from the data analysis. Category 1 described the "empathic labor" process which covers cognitive empathy (including empathic imagination, empathic consideration, and empathic perception) and affective empathy (including natural empathy, surface empathy, and deep empathy). The second category concerns the outcome of nurses' "empathic labor" which incorporates both positive and negative effects. CONCLUSIONS: The findings indicated that hospice nurses' empathy process should be understood as emotional labor. Nursing managers should pay more attention to raising the ability of deep empathy with hospice nurses, and explore more sufficient active empowerment strategies to alleviate the negative impact of empathy on nurses and to strengthen nurses' deep empathy with terminal ill patients.

Antibody-Dependent Enhancement of SARS-CoV-2 Infection of Human Immune Cells: In Vitro Assessment Provides Insight in COVID-19 Pathogenesis.

Patients with COVID-19 generally raise antibodies against SARS-CoV-2 following infection, and the antibody level is positively correlated to the severity of disease. Whether the viral antibodies exacerbate COVID-19 through antibody-dependent enhancement (ADE) is still not fully understood. Here, we conducted in vitro assessment of whether convalescent serum enhanced SARS-CoV-2 infection or induced excessive immune responses in immune cells. Our data revealed that SARS-CoV-2 infection of primary B cells, macrophages and monocytes, which express variable levels of FcγR, could be enhanced by convalescent serum from COVID-19 patients. We also determined the factors associated with ADE, and found which showed a time-dependent but not viral-dose dependent manner. Furthermore, the ADE effect is not associated with the neutralizing titer or RBD antibody level when testing serum samples collected from different patients. However, it is higher in a medium level than low or high dilutions in a given sample that showed ADE effect, which is similar to dengue. Finally, we demonstrated more viral genes or dysregulated host immune gene expression under ADE conditions compared to the no-serum infection group. Collectively, our study provides insight into the understanding of an association of high viral antibody titer and severe lung pathology in severe patients with COVID-19.

Biosynthesis and Characterization of Medium-Chain-Length Polyhydroxyalkanoate with an Enriched 3-Hydroxydodecanoate Monomer from a Pseudomonas chlororaphis Cell Factory.

Polyhydroxyalkanoates (PHAs) have been reported with agricultural and medical applications in virtue of their biodegradable and biocompatible properties. Here, we systematically engineered three modules for the enhanced biosynthesis of medium-chain-length polyhydroxyalkanoate (mcl-PHA) in Pseudomonas chlororaphis HT66. The phzE, fadA, and fadB genes were deleted to block the native phenazine pathway and weaken the fatty acid ß-oxidation pathway. Additionally, a PHA depolymerase gene phaZ was knocked out to prevent the degradation of mcl-PHA. Three genes involved in the mcl-PHA biosynthesis pathway were co-overexpressed to increase carbon flux. The engineered strain HT4Δ::C1C2J exhibited an 18.2 g/L cell dry weight with 84.9 wt % of mcl-PHA in a shake-flask culture, and the 3-hydroxydodecanoate (3HDD) monomer was increased to 71.6 mol %. Thermophysical and mechanical properties of mcl-PHA were improved with an enriched ratio of 3HDD. This study demonstrated a rational metabolic engineering approach to enhance the production of mcl-PHA with the enriched dominant monomer and improved material properties.

Identification of a Novel Bioactive Phenazine Derivative and Regulation of phoP on Its Production in Streptomyces lomondensis S015.

Natural phenazines are a class of multifunctional secondary metabolites of bacteria that play an important role in the biocontrol of plant pathogens. In this paper, a novel bioactive phenazine derivative was isolated from Streptomyces lomondensis S015 through silica gel chromatography and preparative high-performance liquid chromatography (HPLC). The structure was identified as 1-carboxyl-6-formyl-4,7,9-trihydroxy-phenazine (CFTHP) by NMR spectroscopy in combination with ultraperformance liquid chromatography & mass spectrometry (UPLC-MS). CFTHP could inhibit Pythium ultimum, Rhizoctonia solani, Septoria steviae, and Fusarium oxysporum f. sp. niveum with minimal inhibitory concentration (MIC) values of 16, 32, 16, and 16 µg/mL, respectively. A global regulatory gene phoP could positively regulate CFTHP biosynthesis since its production was 3.0-fold enhanced by phoP overexpression and inhibited by phoP deletion in Streptomyces lomondensis S015. These studies illustrated the potential of CFTHP as a promising biopesticide and provided a reference for phenazine production improvement.

[Effect of electro-nape-acupuncture on hearing in patients with refractory flat descending idiopathic sudden sensorineural hearing loss].

OBJECTIVE: To compare the therapeutic effect of electro-nape-acupuncture (ENA) combined with hyperbaric oxygen therapy (HBOT) and single HBOT on refractory flat descending idiopathic sudden sensorineural hearing loss (ISSNHL). METHODS: A total of 78 patients were randomized into an ENA combined with HBOT (ENA+HBOT) group and a HBOT group, 39 cases in each one. Patients in both groups were treated with oral extract of ginkgo biloba leaves and mecobalamin tablets. On the basis of the conventional medication treatment, HBOT was adopt in the HBOT group. On the basis of the treatment in the HBOT group, electro-nape-acupuncture was applied at Fengchi (GB 20), Gongxue (Extra), Zhongzhu (TE 3), Waiguan (TE 5) and Yifeng (TE 17), Tinggong (SI 19), Tinghui (GB 2) and the vertigo-auditory area of affected side in the ENA+HBOT group. Pulse acupuncture instrument was connected at Fengchi (GB 20) and Gongxue (Extra) for 30 min (with continuous wave, 2 Hz in frequency), the needles were retained for another 30 min after electroaupuncture. The treatment was given once a day, 6 times a week for 4 weeks in both groups. Before the treatment and 2,4 weeks into the treatment, the average auditory threshold, the scores of tinnitus handicap inventory (THI) and dizziness handicap inventory (DHI) were observed, and the therapeutic effect was evaluated in both groups. RESULTS: Compared before treatment, the average auditory threshold, the scores of THI and DHI of 2,4 weeks into the treatment were decreased in both groups (P<0.000 1). Compared with the HBOT group, the average auditory threshold, the scores of THI and DHI of 4 weeks into the treatment were lower in the ENA+HBOT group (P<0.000 1). The total effective rate was 69.2% (27/39) in the ENA+HBOT group and 51.3% (20/39) in the HBOT group, there was no statistical difference (P>0.05). CONCLUSION: Electro-nape- acupuncture can improve the mean auditory threshold and the symptoms of tinnitus and dizziness in patients with refractory flat descending idiopathic sudden sensorineural hearing loss.

Mobile device use and the cognitive function and depressive symptoms of older adults living in residential care homes.

BACKGROUND: With the fast-paced aging and increasing digitalization of society, there has been a growing interest in the effect of mobile device use on cognitive function and depression in older adults. However, research examining this issue among older adults in residential care homes (RCHs) is scant. Therefore, this study aimed to examine the impact of mobile device use on the cognitive function and depressive symptoms of older adults living in RCHs. METHODS: A cross-sectional survey was conducted using a sociodemographic questionnaire, the Montreal Cognitive Assessment (MoCA) and the 15-item Geriatric Depression Scale (GDS-15). RESULTS: A total of 235 senior residents (aged 82.58 ± 5.54) in four RCHs were surveyed. Users of mobile devices had a significantly higher total MoCA score (25.02 ± 4.14) and a significantly lower GDS-15 score (3.28 ± 2.74) than non-users (MoCA: 19.34 ± 5.21, GDS-15: 4.69 ± 2.90). Multivariate linear regression indicate that mobile device use is significantly associated with total MoCA score, six of the seven sub-scores (visuospatial abilities and execution functions, attention, language, abstraction, delayed recall, and orientation)(P < 0.05). Logistic regression showed that mobile device use was significantly associated with the level of depressive symptoms (OR = 0.458, 95%CI = 0.249-0.845). CONCLUSIONS: Use of mobile devices has a significant association with the cognitive function and depressive symptoms of older adults living in RCHs, and thus should be encouraged as a measure to maintain and improve cognition and prevent depression.

Beneficial Effects of Probiotic Treatment on Gut Microbiota in Very Low Birth Weight Infants.

The very low birth weight (VLBW) infant is at great risk for marked dysbiosis of the gut microbiota. In the present study, a total of 36 VLBW infants were randomly divided into two groups, who were treated with combined probiotics and placebo, and 72 fecal specimens on days 14 and 28 of life were collected from them. Finally, 32 fecal specimens extracted from 16 preterm VLBW infants were qualified and analyzed using 16S rRNA gene sequencing. The primary outcome was to evaluate the change of gut microbiota in VLBW infants after combined probiotic supplement. The secondary outcome was to analyze the correlation gut microbial composition and levels of cytokines. We found that probiotic treatment, but not placebo, decreased the α-diversity of gut microbiota in VLBW infants. At the phylum level, probiotic treatment strongly increased the abundance of Firmicutes, whereas that of Proteobacteria was significantly reduced. At the family level, Streptococcaceae and Lactobacillaceae became prevalent after probiotic treatment, while the relative abundance of Enterobacteriaceae was reduced in the meantime. Most notably, significant correlations were observed between Lactobacillaceae abundance and serum cytokine levels. Further studies are required to shed more light on the characteristics of gut microbiota of VLBW neonates. And the modulation of microbiota should be considered to improve the survival rate of VLBW infants.

Studying perceived needs for information on maternal and infant health care in the puerperium period among fathers of newborns in China.

OBJECTIVE: The objective of this study is to understand the perceived needs for information on maternal and infant healthcare during the puerperium among the fathers of newborns in China, and to examine factors that are associated with the patterns of perceived needs. DESIGN: A cross-sectional study was conducted. METHODS: A survey was conducted in the obstetrics department of the First Affiliated Hospital of Soochow University in Suzhou, China. A total of 206 fathers of newborns were interviewed with a response rate of 98.1%. Latent class analysis (LCA) was used to identify a priori unknown patterns of perceived needs for information (knowledge/skills) on maternal and infant healthcare during the puerperium period. Chi-square tests were applied to examine factors associated with such patterns of needs. RESULTS: The majority of the participants perceived strong needs for information on maternal and infant healthcare during the puerperium. LCA identified three latent classes on perceived needs for information on maternal healthcare among Chinese fathers of newborns: Class 1 - Low: Some Infant Health Related Needs; Class 2 - Moderate: Lower Physical Recovery Needs; and Class 3 - High: Enthusiastic Needs. Similarly, three latent classes were identified for perceived needs for information on infant health care: Class 1 - Low: Some Medical Needs; Class 2 - Moderate: Lower Breastfeeding Needs; and Class 3 - High: Enthusiastic Needs. Fathers aged 30 to 35, urban residents, and those with higher education were more likely to be in the Enthusiastic Needs groups for information needs for both maternal and infant healthcare. CONCLUSIONS: Perceived needs for information on maternal and infant healthcare are widespread among fathers of newborns in China. Three distinct latent classes for perceived needs for information (knowledge/skills) on maternal and infant health were identified in this population. Socio-demographics, such as age, residence, and education, were significantly associated with such patterns of needs. The findings have implications for the development of interventions to improve maternal and infant healthcare in China.

Overexpression of GP73 promotes cell invasion, migration and metastasis by inducing epithelial-mesenchymal transition in pancreatic cancer.

Pancreatic cancer is one of the most difficult clinical cases to diagnose with a very low 5-year survival rate of 5%, regardless of the advances made in both the medical and surgical treatment of the disease. One of the contributing factors for the high mortality rate seen of pancreatic cancer patients is the lack of effective chemotherapies, which is believed to be due to drug-resistance. Based on recent evidence, epithelial-mesenchymal transition (ETM) of pancreatic cancer cells has been found to be associated with the development of drug resistance and an increase in cell invasion. Therefore, we conducted the present study in order to investigate the regulatory effects of Golgi protein-73 (GP73) on PC. GP73 and EMT-related gene expressions in PC, along with the adjacent and chronic pancreatitis tissues were determined by means of RT-qPCR and Western blot analysis. Cultured PC cells were treated with pAdTrack-CMV, si-NC, GP73 overexpression, Si-GP73, Snail-siRNA and GP73 + Snail-siRNA. Cell invasion, migration and metastasis were measured in vitro and in vivo. The results revealed that the PC tissues and chronic pancreatitis tissues exhibited diminished E-cadherin expression and amplified GP73, N-cadherin, Vimentin and Snail expression. In response to GP73 gene silencing, PC cells presented with increased E-cadherin expression and decreased N-cadherin, Vimentin, Snail expression in addition to the inhibition of the number of invasive cells, tumor volume and number of liver lesions. These findings highly indicated that the overexpression of GP73 promotes cell invasion, migration and metastasis by inducing EMT in PC.

The analgesic efficacy of subcostal transversus abdominis plane block with Mercedes incision.

BACKGROUND: Conventional perioperative analgesic modalities (e.g. opioids, epidural analgesia) have their own drawbacks, which limit their clinical application. This study investigated the opioid-sparing effectsof the oblique subcostal transversus abdominis plane (OSTAP) blockade with ropivacaine for the patients undergoing open liver resection with a Mercedes incision. METHODS: 126 patients who were scheduled for open liver resection were enrolled in this study. Patients were randomly assigned to receive bilateral ultrasound-guided OSTAPblocks with either 0.375% ropivacaine (groupT) or 0.9% isotonic saline (group C). Both groups also received intravenous patient-controlled analgesia and intravenous 40 mg parecoxib every 12 h for a total of 3 days. Preoperative and intraoperative parameters, plus intraoperative and postoperative cumulative sufentanil consumption, were recorded. RESULTS: 70 patients were enrolled in the study finally. There were no significant differences between the two groups with respect to preoperative parameters, and surgical and anesthetic characteristics. The intraoperative sufentanil use, cumulative sufentanil consumption at 5 min after extubation, 2 h, 4 h,12 h and 24 h after operation in group T was significantly less than that in group C (P = 0.001, 0.001, 0.000, 0.000, 0.001 and 0.044, respectively). Compared with group C, postoperative NRS pain scores at rest were significantly lower at 2 h and 4 h postoperatively in group T (P = 0.04and 0.02, respectively); NRS scores at the time of coughing were also significantly lower in group T than in group C at all time points except 5 min after extubation (all P < 0.001). Furthermore, compared with group C, the number of intraoperative vasodilator use, the extubation time and the incidence of nausea was reduced in group T. CONCLUSION: Ultrasound-guided OSTAP block with ropivacaine can significantly decrease the perioperative cumulative dosage of analgesics and improve analgesic effect without obvious side effects for the patients who underwent an open liver resection with Mercedes incision when compared tothe ultrasound-guided OSTAP block with saline. TRIAL REGISTRATION: The study protocol was registered at http://www.chictr.org.cn (ChiCTR-TRC- 14004827) on February 19, 2014.

KNAT7 positively regulates xylan biosynthesis by directly activating IRX9 expression in Arabidopsis.

Xylan is the major plant hemicellulosic polysaccharide in the secondary cell wall. The transcription factor KNOTTED-LIKE HOMEOBOX OF ARABIDOPSIS THALIANA 7 (KNAT7) regulates secondary cell wall biosynthesis, but its exact role in regulating xylan biosynthesis remains unclear. Using transactivation analyses, we demonstrate that KNAT7 activates the promoters of the xylan biosynthetic genes, IRREGULAR XYLEM 9 (IRX9), IRX10, IRREGULAR XYLEM 14-LIKE (IRX14L), and FRAGILE FIBER 8 (FRA8). The knat7 T-DNA insertion mutants have thinner vessel element walls and xylary fibers, and thicker interfascicular fiber walls in inflorescence stems, relative to wild-type (WT). KNAT7 overexpression plants exhibited opposite effects. Glycosyl linkage and sugar composition analyses revealed lower xylan levels in knat7 inflorescence stems, relative to WT; a finding supported by labeling of inflorescence walls with xylan-specific antibodies. The knat7 loss-of-function mutants had lower transcript levels of the xylan biosynthetic genes IRX9, IRX10, and FRA8, whereas KNAT7 overexpression plants had higher mRNA levels for IRX9, IRX10, IRX14L, and FRA8. Electrophoretic mobility shift assays indicated that KNAT7 binds to the IRX9 promoter. These results support the hypothesis that KNAT7 positively regulates xylan biosynthesis.

Experience-based mediation of feeding and oviposition behaviors in the cotton bollworm: Helicoverpa armigera (Lepidoptera: Noctuidae).

Experience is well known to affect sensory-guided behaviors in many herbivorous insects. Here, we investigated the effects of natural feeding experiences of Helicoverpa armigera larvae on subsequent preferences of larval approaching and feeding, as well as the effect of host-contacting experiences of mated females on subsequent ovipositional preference. The results show that the extent of experience-induced preference, expressed by statistical analysis, depended on the plant species paired with the experienced host plant. Larval feeding preference was much easier to be induced by natural feeding experience than larval approaching preference. Naïve larvae, reared on artificial diet, exhibited clear host-ranking order as follows: tobacco ≥ cotton > tomato > hot pepper. Feeding experiences on hot pepper and tobacco could always induce positive feeding preference, while those on cotton often induced negative effect, suggesting that the direction of host plant experience-induced preference is not related to innate feeding preference. Inexperienced female adults ranked tobacco as the most preferred ovipositional host plant, and this innate preference could be masked or weakened but could not be reversed by host-contacting experience after emergence.