The production of bacterial cellulose in Gluconacetobacter xylinus regulated by luxR overexpression of quorum sensing system.

Quorum sensing is a mechanism that facilitates cell-to-cell communication. Through signal molecular density for signal recognition, which leads to the regulation of some physiological and biochemical functions. Gluconacetobacter xylinus CGMCC 2955, which produces bacterial cellulose (BC), synthesizes the LuxR protein belonging to the LuxI/LuxR type QS system. Here, a luxR overexpression vector was transformed into G. xylinus CGMCC 2955. The overexpression of luxR increased the yield of BC by 15.6% after 16 days static culture and reduced the cell density by 15.5% after 120-h-agitated culture. The glucose was used up by G. xylinus-pMV24-luxR at 72-h-agitated fermentation, which 12 h earlier than the wild-type (WT). The total N-acylhomoserine lactones (AHL) content of the luxR-overexpressing strain and the WT strain attained 1367.9 ± 57.86 mg/L and 842.9 ± 54.22 mg/L, respectively. The C12-HSL and C14-HSL contents of G. xylinus-pMV24-luxR were 202 ± 21.66 mg/L and 409.6 ± 0.91 mg/L, which were significantly lower than that of WT. In contrast, C6-HSL showed opposite results. The difference of AHL content proved that overexpression of luxR improved the binding of AHL and showed preference for some specific AHL. The metabolic results demonstrated that upon glucose exhaustion, the consumption of gluconic acid was promoted by luxR overexpression, and the content of D- ( +)-trehalose, an antiretrograde metabolite, increased significantly. KEY POINTS: • The overexpression of luxR increased the yield of bacterial cellulose • The content of signal molecules was significantly different • Differential metabolites were involved in multiple metabolic pathways.

The miR319-Targeted GhTCP4 Promotes the Transition from Cell Elongation to Wall Thickening in Cotton Fiber.

Plant cell growth involves a complex interplay among cell-wall expansion, biosynthesis, and, in specific tissues, secondary cell wall (SCW) deposition, yet the coordination of these processes remains elusive. Cotton fiber cells are developmentally synchronous, highly elongated, and contain nearly pure cellulose when mature. Here, we report that the transcription factor GhTCP4 plays an important role in balancing cotton fiber cell elongation and wall synthesis. During fiber development the expression of miR319 declines while GhTCP4 transcript levels increase, with high levels of the latter promoting SCW deposition. GhTCP4 interacts with a homeobox-containing factor, GhHOX3, and repressing its transcriptional activity. GhTCP4 and GhHOX3 function antagonistically to regulate cell elongation, thereby establishing temporal control of fiber cell transition to the SCW stage. We found that overexpression of GhTCP4A upregulated and accelerated activation of the SCW biosynthetic pathway in fiber cells, as revealed by transcriptome and promoter activity analyses, resulting in shorter fibers with varied lengths and thicker walls. In contrast, GhTCP4 downregulation led to slightly longer fibers and thinner cell walls. The GhHOX3-GhTCP4 complex may represent a general mechanism of cellular development in plants since both are conserved factors in many species, thus providing us a potential molecular tool for the design of fiber traits.

[Repairing of palatum durum defects following maxillectomy using nasal septum tissue flap].

OBJECTIVE: To discuss the effect of repairing of palatum durum defects following maxillectomy using nasal septum tissue flap. METHODS: Twenty-six patients underwent maxillectomy and the defects were repaired by using full (16 cases) and partial (10 cases) nasal septum tissue flaps. RESULTS: Twenty-one patients were healed by first intention, recovering swallowing and pronunciation function. Five patients suffered from fistula holes, and 2 healed after dressing while 2 of the other 3 patients healed after second suturing with 1 still got a small fistula hole. Facial deformity include 4 exterior cheek mild concave and 6 complained about unsuited false teeth and no dorsal subsidence was found. The 3, 5, 10 year survival rate was 46.2%, 30.8% and 11.5% respectively. CONCLUSIONS: Repairing defects with nasal septum tissue flap has advantages. Nasal septum can not be invaded easily, and the material can be got with ease, with rich blood supply, being resistant to infection, easy to heal and less chance of leading to fistula holes. With the cartilage of nasal septum as support, facial deformity can be reduced. And the method is worth spreading and exploiting.

[Endoscopic maxillary sinus surgery through anterior or posterior nasolacrimal duct approach].

OBJECTIVE: To explore the feasibility and effectiveness of the approaches and methodology of the endoscopic surgery for maxillary sinus lesions through the medial wall of the maxillary sinus. METHODS: From Jun. 2003 to Aug. 2010, endoscopic surgery through anterior or posterior nasolacrimal duct approaches to remove maxillary sinus lesions were conducted in 139 patients. Among them there were 43 cases with inverted papilloma, 63 cases with fungal maxillary sinusitis, 28 cases with maxillary sinus cyst, 3 cases with hemorrhagic necrotic polyps, and 2 cases with osteomas. All patients underwent preoperative CT scans, and patients with inverted papillomas also had MRI tests. Anterior-nasolacrimal canal paths included 3 ways: pyriform aperture, lacrimal bone recess (dissecting nasolacrimal duct or not were 2 subtypes), pyriform aperture-nasolacrimal duct approaches, and 97 patients were treated. Posterior-nasal lacrimal duct paths were also divided into 3 subtypes: the inferior turbinate flip flap, double pedicle inferior turbinate, single pedicle inferior turbinate, and 42 patients were treated. The postoperative effects were observed. RESULTS: All lesions were completely removed under endoscope, the nasolacrimal ducts and inferior turbinates were protected, no nasal lacrimal duct injury and inferior turbinate necrosis were found. Postoperative nasal congestion, headache, swelling discomfort, strange odor, dental pain and numbness and other symptoms gradually disappeared. Nine patients felt nasal dryness, and after nasal washing for about 1 month, the symptom gradually disappeared. Patients were followed up for 6 months to 79 months. In case of osteoma, and hemorrhagic and necrotic polyps, no recurrences were found. Apparent edema, hypertrophy of sinus mucosa could be seen during the surgery in all patients with fungal maxillary sinusitis, and the edema gradually disappeared after 3 months or so, with no relapse. Two cases of maxillary sinus cysts were found in other parts of the maxillary sinus 10 months and 18 months after the surgery, but the cysts were small and asymptomatic, so no further management needed, and they were still under follow-up. Three patients, recurred. In 1 case with inverted papilloma, a local lump on the opening were found 17 months after the surgery, and was removed in out-patient department and pathology showed papillary tumor recurrence, no relapse was found 1 year later; 1 patient had recurrence in anterior ethmoid sinus 15 months after operation, total ethmoidectomy was done and no relapse was found in 3 years. One patient had local recurrence in the posterolateral wall of the maxillary sinus 26 months after operation, and the secondary surgery was done via single pedicle inferior turbinate. The papilloma relapsed again after 1 year, an endoscopic Denker surgery was performed, with no recurrence after 18 months of follow-up. Three months after surgery, the maxillary sinus was scar-covered in all cases. Inferior turbinate maintained good shape, compared to those with inferior nasal meatus windowing surgery. Scars were significantly smaller, but no latch or obstruction of drainage were found. CONCLUSIONS: Endoscopic maxillary sinus surgery through anterior or posterior nasolacrimal duct approach can reduce the trauma, fully expose the sinuses, and facilitate postoperative treatment and review with a window. Retained inferior nasal turbinate is helpful to avoid dryness, crusting, headache and other complications due to too much removal of nasal exteral walls.

[Effect analysis of surgery for treating abnormal styloid process].

OBJECTIVE: To analyze the relationship between pharyngeal paraesthesia and abnormal styloid process, and to evaluate the surgery outcome. METHODS: One hundred and four patients with styloid process abnormality, especially those with pharyngeal paraesthesia were studied preoperatively and postoperatively. RESULTS: Among 104 patients who complained about foreign body sensation of the pharynx and a sore throat, after partial removal of styloid process, 71.2% (74/104) cured (symptoms disappeared), 12.5% (13/104) improved, while 16.3% (17/104) had no improvement. The responding rate was 83.7% (87/104). CONCLUSIONS: Not all abnormality of styloid process subjects would have pharyngeal paraesthesia, so for this kind of cases a more comprehensive analysis is necessary. Surgery via mouth is preferable.