Graft Infection after Prosthetic Bypass Surgery for Infectious Femoral Artery Pseudoaneurysm in Intravenous Drug Users: Manifestation, Management, and Prognosis.

BACKGROUND: The aim of this study is to assess the incidence, clinical manifestations, management, and prognosis of graft infection after bypass surgery with prosthetic conduit for infectious femoral artery pseudoaneurysms (IFAPs) in patients with a history of intravenous drug use (IVDU). METHODS: A single-center retrospective chart review of IVDU presenting with graft infections after previously being treated with extra-anatomic prosthetic conduit bypass surgery for IFAPs between 2009 and 2019 was performed. Relevant clinical data and patient demographics were collected and analyzed. All patients underwent procedures consisting of graft removal with analysis of operative details and complications. RESULTS: Of all 122 patients who underwent IFAP resection with extra-anatomic prosthetic bypass, the incidence of graft infection was 38.5% (47 patients, 48 grafts) with an average age of 35.7 ± 7.3 years. The average interval between bypass surgery and infectious symptoms was 9.2 ± 2.5 months and average time from bypass to graft removal was 13.6 ± 3.4 months. The most common presentation was repeated or unhealable chronic ulcers with sinus formation or purulence either within the bypass area or along the graft conduit route (43, 89.6%). Occlusion of the infected bypass graft occurred in nearly all cases (46, 95.8%). Severe hemorrhage occurred in only 1 case (2.1%). After graft removal, the stumps were ligated in the majority of patients (33, 68.8%) with 15 patients (31.2%) not amenable to ligation due to a difficult dissection. The average time of operation was 35.4 ± 8.7 min with an average blood loss of 35.8 ± 6.7 mL. There were no significant complications such as infection reoccurrence, severe limb ischemia, amputation, or death observed postoperatively. CONCLUSIONS: Patients who receive bypass surgery with prosthetic conduit for IFAPs carry a high incidence of graft infection and subsequent occlusion. However, the presenting symptoms are generally mild, and the incidence of fatal complications is rare. This study suggests that a safe treatment option consists of direct graft removal without reconstruction. Additionally, the procedure proved to be relatively convenient and straightforward, which provides further support toward the strategy of treating IFAPs in IVDUs with pseudoaneurysm resection and prosthetic conduit bypass surgery.

MdMYB9 and MdMYB11 are involved in the regulation of the JA-induced biosynthesis of anthocyanin and proanthocyanidin in apples.

Anthocyanin and proanthocyanidin (PA) are important secondary metabolites and beneficial to human health. Their biosynthesis is induced by jasmonate (JA) treatment and regulated by MYB transcription factors (TFs). However, which and how MYB TFs regulate this process is largely unknown in apple. In this study, MdMYB9 and MdMYB11 which were induced by methyl jasmonate (MeJA) were functionally characterized. Overexpression of MdMYB9 or MdMYB11 promoted not only anthocyanin but also PA accumulation in apple calluses, and the accumulation was further enhanced by MeJA. Subsequently, yeast two-hybrid, pull-down and bimolecular fluorescence complementation assays showed that both MYB proteins interact with MdbHLH3. Moreover, Jasmonate ZIM-domain (MdJAZ) proteins interact with MdbHLH3. Furthermore, chromatin immunoprecipitation-quantitative PCR and yeast one-hybrid assays demonstrated that both MdMYB9 and MdMYB11 bind to the promoters of ANS, ANR and LAR, whereas MdbHLH3 is recruited to the promoters of MdMYB9 and MdMYB11 and regulates their transcription. In addition, transient expression assays indicated that overexpression of MdJAZ2 inhibits the recruitment of MdbHLH3 to the promoters of MdMYB9 and MdMYB11. Our findings provide new insight into the mechanism of how MeJA regulates anthocyanin and PA accumulation in apple.

[Treatment Effect of Corncob and Rice Straw Enhanced Subsurface Flow Constructed Wetland on Low C/N Ratio Wastewater].

The lack of carbon sources severely inhibits denitrification in wastewater with a low C/N ratio. Corncob and rice straw were chosen as supplementary carbon sources to bring into the wetland system to supplement the carbon sources needed for denitrification, and the enhancing effects of the two carbon sources on nitrogen removal from the wetland were studied. The cumulative release of carbon was in the order of rice straw[(145.17±9.44) mg·g-1]>corncob[(57.41±5.04) mg·g-1] based on the 11-day pure water extraction and release experiment, whereas the cumulative release of nitrogen was in the order of rice straw[(2.31±0.09) mg·g-1]>corncob[(0.66±0.08) mg·g-1]. The average carbon/nitrogen ratios released and accumulated by corncob and rice straw during the observation period were 94.78 and 63.64, respectively. Corncob was more suited as an additional carbon source than rice straw. COD concentrations in the effluent from the corncob and straw constructed wetlands were found to be below 50 mg·L-1 for the 58-day pilot test of subsurface flow constructed wetlands, except on days 8 to 12. The NO3--N removal rates of the corncob-added built wetlands were 93%-99% over the observation period, with good denitrification performance. In comparison, the lowest NO3--N removal rate of the constructed wetland with the addition of rice straw was only 76.8% at the late stage of operation, and the denitrification rate dropped dramatically. The control group removal rates of NO3--N were only 76.2%-77.7%, indicating a clear lack of carbon sources. The accumulation of NO2--N was also induced by a lack of carbon supply. NO2--N effluent concentrations were 2.5-6 times and 6-26 times higher in the constructed wetlands with rice straw and the control groups, respectively, than those in the wetlands constructed with corncob. The addition of corncob resulted in a more substantial reduction in NO2--N content in the constructed wetland than the addition of rice straw (P<0.05). The TN removal rates of wetlands constructed with corncob and rice straw and the control group were 83.75%-93.49%, 76.59%-78.85%, and 67.85%-72.56%, respectively, with significant differences among the three (P<0.01). Finally, pretreatment with dilute alkali heating raised the cumulative carbon release of corncob to (93.73±17.49) mg·g-1 and the carbon/nitrogen ratio to 175.8, significantly improving the carbon release performance of corncob and demonstrating that it is a suitable source of extra carbon.

MdHIR proteins repress anthocyanin accumulation by interacting with the MdJAZ2 protein to inhibit its degradation in apples.

In higher plants, jasmonate ZIM-domain (JAZ) proteins negatively regulate the biosynthesis of anthocyanins by interacting with bHLH transcription factors. However, it is largely unknown if and how other regulators are involved in this process. In this study, the apple MdJAZ2 protein was characterized in regards to its function in the negative regulation of anthocyanin accumulation and peel coloration. MdJAZ2 was used as a bait to screen a cDNA library using the yeast two-hybrid method. The hypersensitive induced reaction (HIR) proteins, MdHIR2 and MdHIR4, were obtained from this yeast two-hybrid. The ZIM domain of MdJAZ2 and the PHB domain of the MdHIR proteins are necessary for their interactions. The interactions were further verified using an in vitro pull-down assay. Subsequently, immunoblotting assays demonstrated that MdHIR4 enhanced the stability of the MdJAZ2-GUS protein. Finally, a viral vector-based transformation method showed that MdHIR4 inhibited anthocyanin accumulation and fruit coloration in apple by modulating the expression of genes associated with anthocyanin biosynthesis.

The apple WD40 protein MdTTG1 interacts with bHLH but not MYB proteins to regulate anthocyanin accumulation.

The abundance of anthocyanins and proanthocyanins in apples is tightly regulated by three classes of regulatory factors, MYB, bHLH and WD40 proteins, only some of which have been previously identified. In this study, we identified an apple WD40 protein (MdTTG1) that promotes the accumulation of anthocyanins. The biosynthetic genes required downstream in the flavonoid pathway were up-regulated when MdTTG1 was over-expressed in Arabidopsis. Consistent with its role as a transcriptional regulator, an MdTTG1-GFP fusion protein was observed only in the nucleus. We assayed the expression patterns of this gene in different organs and found that they were positively correlated with anthocyanin accumulation in the apple. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that MdTTG1 interacted with bHLH transcription factors (TFs) but not MYB protein, whereas bHLH was known to interact with MYB in apples. However, based on a ChIP assay, MdTTG1 does not appear to bind to the promoter of the anthocyanin biosynthetic genes MdDFR and MdUFGT. Taken together, these results suggest that the apple WD40 protein MdTTG1 interacts with bHLH but not MYB proteins to regulate anthocyanin accumulation.

Ectopic expression of an apple apomixis-related gene MhFIE induces co-suppression and results in abnormal vegetative and reproductive development in tomato.

It has been well documented that FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) plays important regulatory roles in diverse developmental processes in model plant Arabidopsis thaliana. However, it is largely unknown how FIE genes function in economically important crops. In this study, MhFIE gene, which was previously isolated from apomictic tea crabapple (Malus hupehensis Redh. var. pingyiensis), was introduced into tomato. The hemizygous transgenic tomato lines produced curly leaves and decreased in seed germination. In addition, the co-suppression of the transgenic MhFIE and endogenous (SlFIE) genes occurred in homozygous transgenic tomatoes. As a result, FIE silencing brought about abnormal phenotypes during reproductive development in tomato, such as increased sepal and petal numbers in flower, a fused ovule and pistil and parthenocarpic fruit formation. A yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC) demonstrated that MhFIE interacted with a tomato protein, EZ2 (SlEZ2). Its ectopic expression and SlFIE co-suppression notably influenced the expression of genes associated with leaf, flower, and fruit development. Therefore, together with other PcG proteins, FIE was involved in the regulation of vegetative and reproductive development by modulating the expression of related genes in plants.