Divalent nutrient cations: Friend and foe during zinc stress in rice.

Zn deficiency is the most common micronutrient deficit in rice but Zn is also a widespread industrial pollutant. Zn deficiency responses in rice are well documented, but comparative responses to Zn deficiency and excess have not been reported. Therefore, we compared the physiological, transcriptional and biochemical properties of rice subjected to Zn starvation or excess at early and later treatment stages. Both forms of Zn stress inhibited root and shoot growth. Gene ontology analysis of differentially expressed genes highlighted the overrepresentation of Zn transport and antioxidative defense for both Zn stresses, whereas diterpene biosynthesis was solely induced by excess Zn. Divalent cations (Fe, Cu, Ca, Mn and Mg) accumulated in Zn-deficient shoots but Mg and Mn were depleted in the Zn excess shoots, mirroring the gene expression of non-specific Zn transporters and chelators. Ascorbate peroxidase activity was induced after 14 days of Zn starvation, scavenging H2 O2 more effectively to prevent leaf chlorosis via the Fe-dependent Fenton reaction. Conversely, excess Zn triggered the expression of genes encoding Mg/Mn-binding proteins (OsCPS2/4 and OsKSL4/7) required for antimicrobial diterpenoid biosynthesis. Our study reveals the potential role of divalent cations in the shoot, driving the unique responses of rice to each form of Zn stress.

Effects of benzyl viologen on increasing NADH availability, acetate assimilation, and butyric acid production by Clostridium tyrobutyricum.

Clostridium tyrobutyricum produces butyric and acetic acids from glucose. The butyric acid yield and selectivity in the fermentation depend on NADH available for acetate reassimilation to butyric acid. In this study, benzyl viologen (BV), an artificial electron carrier that inhibits hydrogen production, was used to increase NADH availability and butyric acid production while eliminating acetic acid accumulation by facilitating its reassimilation. To better understand the mechanism of and find the optimum condition for BV effect on enhancing acetate assimilation and butyric acid production, BV at various concentrations and addition times during the fermentation were studied. Compared with the control without BV, the addition of 1 µM BV increased butyric acid production from glucose by ∼50% in yield and ∼29% in productivity while acetate production was completely inhibited. Furthermore, BV also increased the coutilization of glucose and exogenous acetate for butyric acid production. At a concentration ratio of acetate (g/L) to BV (mM) of 4, both acetate assimilation and butyrate biosynthesis increased with increasing the concentrations of BV (0-6.25 µM) and exogenous acetate (0-25 g/L). In a fed-batch fermentation with glucose and ∼15 g/L acetate and 3.75 µM BV, butyrate production reached 55.9 g/L with productivity 0.93 g/L/h, yield 0.48 g/g, and 97.4% purity, which would facilitate product purification and reduce production cost. Manipulating metabolic flux and redox balance via BV and acetate addition provided a simple to implement metabolic process engineering approach for butyric acid production from sugars and biomass hydrolysates.

Temporal bone squamous cell carcinoma: A change in treatment.

Temporal bone squamous cell carcinoma (TBSCC) is a rare head and neck malignancy with the incidence 0.8 -1.0 cases in 1 million population. We are reporting a case series on the TBSCC cases that were operated on at Sarawak General Hospital, Malaysia. Ten patients were identified and collected with the presentation and type of surgery performed. It has been challenging for us to manage with recorded 2 years surviving in 6 out of 10 patients operated within this period. An adequate management with proper surgical resection of tumour and radiotherapy can extend the life expectancy for TBSCC patients.

Comparison of single and dual latent tuberculosis screening strategies before biologic and targeted therapy in patients with rheumatic diseases: a retrospective cohort study.

PURPOSE: Before biologic and targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) treatment, latent tuberculosis infection (LTBI) screening by tuberculin skin test (TST) or interferon gamma release assay (IGRA) is recommended. However, both tests have reduced reliability in immunosuppressed patients. We investigated whether dual LTBI screening with both tests could reduce the incidence of tuberculosis. METHODS: Consecutive patients receiving b/tsDMARDs for rheumatic diseases in a regional hospital were recruited. All patients underwent either TST/IGRA or both. They were categorised into a single or dual testing group and were followed up for at least 6 months. Isoniazid was prescribed if any one test was positive. RESULTS: In total, 217 patients were included in this study; 121 underwent single LTBI testing and 96 underwent dual testing. Tuberculosis occurred in nine patients in the single testing group and one patient in the dual testing group (7.4% vs 1.0%, P=0.045). However, the difference was not statistically significant when follow-up duration was considered (log rank test). In total, 71 patients tested positive for LTBI with isoniazid treatment (28.9% in the single testing group and 45.8% in the dual testing group, P=0.007). Agreement between the IGRA and TST was 74.4% (Cohen's kappa=0.413); agreement was lower in patients receiving prednisolone. Infliximab use was independently associated with tuberculosis (P=0.032). Mild isoniazid-related side-effects occurred in seven patients. CONCLUSIONS: Dual LTBI testing with both TST and IGRA is effective and safe. It might be useful for patients receiving prednisolone at the time of LTBI screening, or if infliximab therapy is anticipated.

Fabrication of Ultraviolet Photodetectors Based on Fe-Doped ZnO Nanorod Structures.

In this paper, 100 nm-thick zinc oxide (ZnO) films were deposited as a seed layer on Corning glass substrates via a radio frequency (RF) magnetron sputtering technique, and vertical well-aligned Fe-doped ZnO (FZO) nanorod (NR) arrays were then grown on the seed layer-coated substrates via a low-temperature solution method. FZO NR arrays were annealed at 600 °C and characterized by using field emission scanning microscopy (FE-SEM) and X-ray diffraction spectrum (XRD) analysis. FZO NRs grew along the preferred (002) orientation with good crystal quality and hexagonal wurtzite structure. The main ultraviolet (UV) peak of 378 nm exhibited a red-shifted phenomenon with Fe-doping by photoluminescence (PL) emission. Furthermore, FZO photodetectors (PDs) based on metal-semiconductor-metal (MSM) structure were successfully manufactured through a photolithography procedure for UV detection. Results revealed that compared with pure ZnO NRs, FZO NRs exhibited a remarkable photosensitivity for UV PD applications and a fast rise/decay time. The sensitivities of prepared pure ZnO and FZO PDs were 43.1, and 471.1 for a 3 V applied bias and 380 nm UV illumination, respectively.

Dilemma in management of cervico-facial cystic hygroma.

Cervico facial cystic hygroma and tongue lymphagioma is rare representative of spectrum of lymphatic malformations. Conservative management with sclerosants alone has proven to be successful. However, sudden enlargement of these cervico facial lymphangiomas leads to catastrophic airway obstruction leading to debility in feeding and speech. Therefore, surgery is indicated in such case to prevent such a catastrophic problem. We report here the case of a 3-yearold boy with cervico facial hygroma involving the tongue. We successfully treated him with a combination of surgery and OK432 injection.

A study of human neutrophil antigen genotype frequencies in Hong Kong.

BACKGROUND: Alloantibodies against human neutrophil antigens (HNA) are associated with a variety of clinical conditions. Over the past decade, the allelic and genotypic frequencies of the five HNA systems have been evaluated. Although the HNA system is less polymorphic than human leukocyte antigens (HLA), significant differences in the genotypic and allele frequencies still exist in different populations, even those living in close proximity. OBJECTIVES: To delineate HNA genotypic and allele frequencies to provide vital information on estimating the risk of HNA-associated diseases for our local population. METHODS: Using a validated, in-house-developed assay, genotyping for HNA-1, HNA-3, HLA-4 and HNA-5 was performed on 300 samples from Chinese blood donors from Hong Kong. In addition, the frequency of the HNA-2 c.843A > T allele was also determined. RESULTS: The allele frequencies of HNA-1a, -1b and -1c alleles were 67·8, 31·5 and 0%, respectively, whereas the frequencies of HNA-3a and HNA-3b were 71·0 and 29·0%, respectively. The frequencies of HNA-4a and -4b alleles were 99·5 and 0·5%, respectively, and for HNA-5a and -5b, alleles were 85·2 and 14·8%, respectively. Homozygotes for the HNA-2 c.843 TT variant were absent in our population, whereas only <4% of the population were c.843AT heterozygote carriers. CONCLUSIONS: This is the first study to define HNA genotype and allele frequencies using a validated modified in-house PCR-SSP method in the Hong Kong Chinese blood donor population. Our approach provides a cost-effective assay for conducting routine HNA typing and facilitates the incorporation of these assays into routine clinical service. Our results are comparable with those reported in the Guangzhou Chinese population, but the allele frequencies in our Hong Kong Chinese population are significantly different from the reported European frequencies, confirming that a geographical difference exists for HNA allele frequencies.

A screen-printed carbon electrode modified with gold nanoparticles, poly(3,4-ethylenedioxythiophene), poly(styrene sulfonate) and a molecular imprint for voltammetric determination of nitrofurantoin.

A molecularly imprinted polymer (MIP) and a nanocomposite prepared from gold nanoparticles (AuNP) and poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) were deposited on a screen-printed carbon electrode (SPCE). The nanocomposite was prepared by one-pot simultaneous in-situ formation of AuNPs and PEDOT:PSS and was then inkjet-coated onto the SPCE. The MIP film was subsequently placed on the modified SPCE by co-electrodeposition of o-phenylenediamine and resorcinol in the presence of the antibiotic nitrofurantoin (NFT). Using differential pulse voltammetry (DPV), response at the potential of ~ 0.1 V (vs. Ag/AgCl) is linear in 1 nM to 1000 nM NFT concentration range, with a remarkably low detection limit (at S/N = 3) of 0.1 nM. This is two orders of magnitude lower than that of the control MIP sensor without the nanocomposite interlayer, thus showing the beneficial effect of AuNP-PEDOT:PSS. The electrode is highly reproducible (relative standard deviation 3.1% for n = 6) and selective over structurally related molecules. It can be re-used for at least ten times and was found to be stable for at least 45 days. It was successfully applied to the determination of NFT in (spiked) feed matrices and gave good recoveries. Graphical abstract Schematic representation of a voltammetric sensor for the determination of nitrofurantoin. The sensor is based on a screen-printed carbon electrode (SPCE) modified with an inkjet-printed gold nanoparticles-poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) nanocomposite and a molecularly imprinted polymer.

A review of surgical and audiological outcomes of bonebridge at tertiary centres in Malaysia.

OBJECTIVES: To investigate the surgical and audiological outcome of Bonebridge (BB) at tertiary centres in Malaysia. STUDY DESIGN: Prospective, intra-subject repeated measurements of which each subject is his/her own control, from year 2012 to 2016 at two tertiary referral centres. METHODS: Twenty patients with hearing loss who fulfilled criteria for BB and showed good response to bone conduction hearing aid trial were included. Implantations of BB were carried out under general anaesthesia with preoperative computed tomography (CT) planning. Complications were monitored up to six months postoperatively. Subjects' audiometric thresholds for air conduction, bone conduction and sound field at frequencies of 250Hz to 8kHz were assessed preoperatively and at six months postoperatively. Subjects' satisfaction was evaluated at 6 months post operatively with Hearing Device Satisfaction Scale (HDSS) questionnaire. RESULTS: There was no major complication reported. Mean aided sound field thresholds showed significant improvement for more than 30dB from 500 to 4000kHz (p<0.05). There was no significant change in mean unaided air conduction and bone conduction thresholds pre and post operatively from 500 to 4000kHz, with a difference of less than 5dB (p>0.05). All the patients were very satisfied (>80%) with the implant, attributing to the promising functional outcome and acceptable cosmetic appearance. CONCLUSIONS: BB implantation surgery is safe and is effective in restoring hearing deficits among patients aged five and above with conductive or mixed hearing loss and single-sided hearing loss.

Pilot study comparing steroid-impregnated and non-steroid-impregnated absorbable nasal dressing following endoscopic sinus surgery.

INTRODUCTION: Endoscopic sinus surgery (ESS) is the mainstay for treatment of chronic rhinosinusitis versus maximal medical therapy. We propose a more economical option, by using steroid-impregnated Gelfoam instead of Nasopore post ESS, as it is less expensive and has showed effectiveness in preventing post-operative bleeding. MATERIALS AND METHODS: A randomised, double-blinded, placebo-controlled trial was carried out in eight patients with chronic rhinosinusitis or nasal polyposis who were planned for bilateral endoscopic sinus surgery. A Peri-operative Sinus Endoscopy (POSE) Score and Lund-Kennedy Endoscopic Score (LKES) were recorded. The use of hydrocortisone-impregnated Gelfoam dressing versus normal saline-impregnated Gelfoam dressing were compared. Scores were repeated post-operatively at one week, three weeks and three months interval. RESULTS: For LKES, at the end of three months, 50% of the patients had the same score difference, 37.5% had better results on the study side while 12.5% had better results on the control side. Meanwhile, for POSE Score, at the end of three months, 75% of the patients had better score difference on the study side while 12.5% had better results on the control side. CONCLUSION: Gelfoam can be used as nasal packing material to deliver topical steroid after endoscopic sinus surgery. Steroid-impregnated nasal dressing after endoscopic sinus surgery may not provide better long-term outcome.

A new experience of auditory brainstem implantation in Malaysia.

Auditory brainstem implantation (ABI) is the only solution to restore hearing when cochlear nerves are disrupted together with the pathologies where bilateral cochleae do not provide a suitable location for cochlear implantation. We reported first two successful auditory brainstem implantation cases in patients with neurofibromatosis Type II (NF2) with bilateral acoustic neuroma causing bilateral profound sensorineural hearing loss in Malaysia. A good candidate selection, dedicated surgeons and rehabilitation team as well as strong family support are the crucial factors in achieving the best possible surgical, audiological and speech outcomes.

Metabolic engineering of Clostridium tyrobutyricum for n-butanol production from sugarcane juice.

Clostridium tyrobutyricum is a promising organism for butyrate and n-butanol production, but cannot grow on sucrose. Three genes (scrA, scrB, and scrK) involved in the sucrose catabolic pathway, along with an aldehyde/alcohol dehydrogenase gene, were cloned from Clostridium acetobutylicum and introduced into C. tyrobutyricum (Δack) with acetate kinase knockout. In batch fermentation, the engineered strain Ct(Δack)-pscrBAK produced 14.8-18.8 g/L butanol, with a high butanol/total solvent ratio of ∼0.94 (w/w), from sucrose and sugarcane juice. Moreover, stable high butanol production with a high butanol yield of 0.25 g/g and productivity of 0.28 g/L∙h was obtained in batch fermentation without using antibiotics for selection pressure, suggesting that Ct(Δack)-pscrBAK is genetically stable. Furthermore, sucrose utilization by Ct(Δack)-pscrBAK was not inhibited by glucose, which would usually cause carbon catabolite repression on solventogenic clostridia. Ct(Δack)-pscrBAK is thus advantageous for use in biobutanol production from sugarcane juice and other sucrose-rich feedstocks.

Sinonasal angioleiomyoma.

BACKGROUND: Angioleiomyoma of the nasal cavity is an extremely rare benign neoplasm. It usually occurs in the lower extremities. Up to date, only few cases of angioleiomyoma have been reported. First case of angioleiomyoma of nasal cavity was reported in 1966. We report a rare case of angioleiomyoma arising from the right maxillary sinus. CASE REPORT: A 43-year-old lady presented with recurrent epistaxis and right nasal obstruction for two months duration. Clinical examination revealed a huge right nasal mass obstructing the right nasal cavity. The tumour was excised completely via endoscopic endonasal surgical approach. Histopathological examination confirmed the tumour is sinonasal angioleiomyoma. Postoperatively, she recovered well without any recurrence after a year of followup. CONCLUSION: This tumour has an excellent prognosis and recurrence is extremely rare if excised completely.

Metabolic engineering of Clostridium tyrobutyricum for n-butanol production through co-utilization of glucose and xylose.

The glucose-mediated carbon catabolite repression (CCR) in Clostridium tyrobutyricum impedes efficient utilization of xylose present in lignocellulosic biomass hydrolysates. In order to relieve the CCR and enhance xylose utilization, three genes (xylT, xylA, and xylB) encoding a xylose proton-symporter, a xylose isomerase and a xylulokinase, respectively, from Clostridium acetobutylicum ATCC 824 were co-overexpressed with aldehyde/alcohol dehydrogenase (adhE2) in C. tyrobutyricum (Δack). Compared to the strain Ct(Δack)-pM2 expressing only adhE2, the mutant Ct(Δack)-pTBA had a higher xylose uptake rate and was able to simultaneously consume glucose and xylose at comparable rates for butanol production. Ct(Δack)-pTBA produced more butanol (12.0 vs. 3.2 g/L) with a higher butanol yield (0.12 vs. 0.07 g/g) and productivity (0.17 vs. 0.07 g/L · h) from both glucose and xylose, while Ct(Δack)-pM2 consumed little xylose in the fermentation. The results confirmed that the CCR in C. tyrobutyricum could be overcome through overexpressing xylT, xylA, and xylB. The mutant was also able to co-utilize glucose and xylose present in soybean hull hydrolysate (SHH) for butanol production, achieving a high butanol titer of 15.7 g/L, butanol yield of 0.24 g/g, and productivity of 0.29 g/L · h. This study demonstrated the potential application of Ct(Δack)-pTBA for industrial biobutanol production from lignocellulosic biomass.

Metabolic process engineering of Clostridium tyrobutyricum Δack-adhE2 for enhanced n-butanol production from glucose: effects of methyl viologen on NADH availability, flux distribution, and fermentation kinetics.

Butanol biosynthesis through aldehyde/alcohol dehydrogenase (adhE2) is usually limited by NADH availability, resulting in low butanol titer, yield, and productivity. To alleviate this limitation and improve n-butanol production by Clostridium tyrobutyricum Δack-adhE2 overexpressing adhE2, the NADH availability was increased by using methyl viologen (MV) as an artificial electron carrier to divert electrons from ferredoxin normally used for H2 production. In the batch fermentation with the addition of 500 µM MV, H2 , acetate, and butyrate production was reduced by more than 80-90%, while butanol production increased more than 40% to 14.5 g/L. Metabolic flux analysis revealed that butanol production increased in the fermentation with MV because of increased NADH availability as a result of reduced H2 production. Furthermore, continuous butanol production of ∼55 g/L with a high yield of ∼0.33 g/g glucose and extremely low ethanol, acetate, and butyrate production was obtained in fed-batch fermentation with gas stripping for in situ butanol recovery. This study demonstrated a stable and reliable process for high-yield and high-titer n-butanol production by metabolically engineered C. tyrobutyricum by applying MV as an electron carrier to increase butanol biosynthesis.

Metabolic engineering of Clostridium tyrobutyricum for n-butanol production from maltose and soluble starch by overexpressing α-glucosidase.

Clostridium tyrobutyricum does not have the enzymes needed for using maltose or starch. Two extracellular α-glucosidases encoded by agluI and agluII from Clostridium acetobutylicum ATCC 824 catalyzing the hydrolysis of α-1,4-glycosidic bonds in maltose and starch from the non-reducing end were cloned and expressed in C. tyrobutyricum (Δack, adhE2), and their effects on n-butanol production from maltose and soluble starch in batch fermentations were studied. Compared to the parental strain grown on glucose, mutants expressing agluI showed robust activity in breaking down maltose and produced more butanol (17.2 vs. 9.5 g/L) with a higher butanol yield (0.20 vs. 0.10 g/g) and productivity (0.29 vs. 0.16 g/L h). The mutant was also able to use soluble starch as substrate, although at a slower rate compared to maltose. Compared to C. acetobutylicum ATCC 824, the mutant produced more butanol from maltose (17.2 vs. 11.2 g/L) and soluble starch (16.2 vs. 8.8 g/L) in batch fermentations. The mutant was stable in batch fermentation without adding antibiotics, achieving a high butanol productivity of 0.40 g/L h. This mutant strain thus can be used in industrial production of n-butanol from maltose and soluble starch.

Engineering Clostridium acetobutylicum with a histidine kinase knockout for enhanced n-butanol tolerance and production.

Clostridium acetobutylicum JB200, a mutant strain of C. acetobutylicum ATCC 55025 obtained through strain evolution in a fibrous bed bioreactor, had high butanol tolerance and produced up to ~21 g/L butanol from glucose in batch fermentation, an improvement of ~67 % over the parental strain (~12.6 g/L). Comparative genomic analysis revealed a single-base deletion in the cac3319 gene leading to C-terminal truncation in its encoding histidine kinase (HK) in JB200. To study the effects of cac3319 mutation on cell growth and fermentation, the cac3319 gene in ATCC 55025 was disrupted using the ClosTron group II intron-based gene inactivation system. Compared to ATCC 55025, the cac3319 HK knockout mutant, HKKO, produced 44.4 % more butanol (18.2 ± 1.3 vs. 12.6 ± 0.2 g/L) with a 90 % higher productivity (0.38 ± 0.03 vs. 0.20 ± 0.02 g/L h) due to increased butanol tolerance, confirming, for the first time, that cac3319 plays an important role in regulating solvent production and tolerance in C. acetobutylicum. This work also provides a novel metabolic engineering strategy for generating high-butanol-tolerant and high-butanol-producing strains for industrial applications.

Metabolic engineering of Clostridium tyrobutyricum for n-butanol production: effects of CoA transferase.

The overexpression of CoA transferase (ctfAB), which catalyzes the reaction: acetate/butyrate + acetoacetyl-CoA → acetyl/butyryl-CoA + acetoacetate, was studied for its effects on acid reassimilation and butanol biosynthesis in Clostridium tyrobutyricum (Δack, adhE2). The plasmid pMTL007 was used to co-express adhE2 and ctfAB from Clostridium acetobutylicum ATCC 824. In addition, the sol operon containing ctfAB, adc (acetoacetate decarboxylase), and ald (aldehyde dehydrogenase) was also cloned from Clostridium beijerinckii NCIMB 8052 and expressed in C. tyrobutyricum (Δack, adhE2). Mutants expressing these genes were evaluated for their ability to produce butanol from glucose in batch fermentations at pH 5.0 and 6.0. Compared to C. tyrobutyricum (Δack, adhE2) without expressing ctfAB, all mutants with ctfAB overexpression produced more butanol, with butanol yield increased to 0.22 - 0.26 g/g (vs. 0.10 - 0.13 g/g) and productivity to 0.35 g/l h (vs. 0.13 g/l h) because of the reduced acetate and butyrate production. The expression of ctfAB also resulted in acetone production from acetoacetate through a non-enzymatic decarboxylation.