Enhanced production of a novel cytotoxic chromone oxalicumone A by marine-derived mutant Penicillium oxalicum SCSIO 24–2

Many marine natural products hold great potential for the development of new and much needed drugs. However, the production of active metabolites by marine-derived microorganisms is usually very low, and large-scale culture has to be involved to meet the need of chemical structural modification and deep pharmacy study. In order to enhance the production of a novel cytotoxic sulfur-containing chromone oxalicumone A (OA), germinating spores of a marine-derived wild strain Penicillium oxalicum SCSGAF 0023 were mutated by microwave and ultraviolet light irradiation, which led to the obtainment of a mutant P. oxalicum SCSIO 24–2 that could produce fivefold increase in OA production (3.42?±?0.21 mg/l) as compared to the wild strain. This is the first report that germinating spores are applied in marine-derived Penicillium sp. mutating to enhance the production of OA. Further, Plackett–Burman design and central composite design were adopted to optimize the basic medium components for increasing OA production by the mutant SCSIO 24–2 in shake flasks. The results indicated that three medium components including mannitol, maltose, and l-cysteine had significant effects on OA production, and their concentrations were optimized as 36, 27.9, and 0.99 g/l, respectively. In the optimized medium, the OA production (18.31?±?0.27 mg/l) by mutant SCSIO 24–2 was 4.4-fold higher than that in the basic medium. These results of this work promise to improve the present production of OA and may be adopted to enhance other objective products' production by marine-derived fungi.     

3,5-Diiodo-l-thyronine ameliorates diabetic nephropathy in streptozotocin-induced diabetic rats

3, 5-Diiodothyronine (T2), a natural metabolite of triiodothyronine (T3) from deiodination pathway, can mimic biologic effects of T3 without inducing thyrotoxic effects. Recent studies revealed T3 acted as a protective factor against diabetic nephropathy (DN). Nevertheless, little is known about the effect of T2 on DN. This study was designed to investigate whether and how T2 affects experimental models of DN in vivo and in vitro. Administration of T2 was found to prevent significant decrease in SIRT1 protein expression and activity as well as increases in blood glucose, urine albumin excretion, matrix expansion, transforming growth factor-β1 expression, fibronectin and type IV collagen deposition in the diabetic kidney. Concordantly, similar effects of T2 were exhibited in the cultured rat mesangial cells (RMC) exposed to high glucose and that could be abolished by a known SIRT1 inhibitor, sirtinol. Moreover, enhanced NF-κB acetylation and JNK phosphorylation present in both diabetic rats and high glucose-treated RMC were distinctly dampened by T2. Collectively, these results suggested that T2 was a protective agent against renal damage in diabetic nephropathy, whose action involved regulation of SIRT1.     

Morphological,Molecular and Pathological Characterization of Phytophthora amaranthi sp. nov. from Amaranth in Taiwan

In the spring of 2007, a serious disease on amaranth was noticed in several farms in the major amaranth production area in central Taiwan. Abundant oospores were found in the disease tissues. A species of Phytophthora was consistently isolated from disease tissues. The organism formed abundant oospores with smooth walls and with amphigynous antheridia in single culture. Sporangia were partially deciduous with short‐ to medium‐length pedicels. Morphological characteristics of this organism did not match any reported Phytophthora species, and the organism was named Phytophthora amaranthi. Pathogenicity tests and molecular characterization confirmed the identity of the organism as a new pathogen of amaranth and a new species of Phytophthora.     

火龙果茎基因组DNA提取方法改良

火龙果(Hylocereus undulatus)是近年发展起来的一种新兴热带水果, 其茎富含多糖、多酚及其它次生代谢物, 黏性极大, 很难从中提取高质量的DNA。特别是一年生以上的老茎, 目前尚未有较好的DNA提取方法。为了解决这一难题, 该研究对CTAB+Tris-HCl洗涤法进行了3种方式的改良。结果表明, “改进三”方法可不受取样时期和取样部位的限制, 从一年生以上火龙果茎中提取的DNA质量最好且不含黏性物质, 可用于酶切与分子标记等生化和分子生物学实验。该研究探索了一条较为理想的火龙果茎DNA提取方法, 值得推广应用。     

Genetic differentiation of Pseudoregma bambucicola population based on mtDNA COII gene

mtDNA COII gene sequences were identified and analyzed using different types of software, namely, MEGA5.0, DNAMAN, and DnaSP5.0 in four Chinese provinces, namely, Sichuan, Zhejiang, Guizhou and Shanghai. Analysis of molecular genetic variation and its genetic structure and differentiation, combined with NJ tree, MP tree analysis and analysis of molecular variance (AMOVA), at Fst = 0.0582 conclude that the genetic differentiation is low, gene flow is Nm = 8.0911, and gene exchange is sufficient. However, for the geographic populations of Pseudoregma bambucicola in the four provinces, their gene exchange is relatively weak at Nm = 0.8284, whereas the genetic differentiation is high at Fst = 0.3764. Based on the data, total nucleotide diversity between the populations is 0.00158 ± 0.00021. The results showed that the total population of Tajima’s D and Fu’s Fs results are D = ?0.885 and Fs = 0.226, respectively. The experimental numerical results showed that this total population is not significant (P > 0.10), indicating that nine different geographic populations are short-term. No expansion occurred in the internal population. This study provided a theoretical and practical basis for the comprehensive prevention and control of P. bambucicola.     

Sense-overlapping lncRNA as a decoy of translational repressor protein for dimorphic gene expression

Long noncoding RNAs (lncRNAs) are vastly transcribed and extensively studied but lncRNAs overlapping with the sense orientation of mRNA have been poorly studied. We analyzed the lncRNA DAPALR overlapping with the 5´ UTR of the Doublesex1 (Dsx1), the male determining gene in Daphnia magna. By affinity purification, we identified an RNA binding protein, Shep as a DAPALR binding protein. Shep also binds to Dsx1 5´ UTR by recognizing the overlapping sequence and suppresses translation of the mRNA. In vitro and in vivo analyses indicated that DAPALR increased Dsx1 translation efficiency by sequestration of Shep. This regulation was impaired when the Shep binding site in DAPALR was deleted. These results suggest that Shep suppresses the unintentional translation of Dsx1 by setting a threshold; and when the sense lncRNA DAPALR is expressed, DAPALR cancels the suppression caused by Shep. This mechanism may be important to show dimorphic gene expressions such as sex determination and it may account for the binary expression in various developmental processes.     

Aldose reductase is a potent regulator of TGF-β1 induced expression of fibronectin in human mesangial cells

Glomerulosclerosis is considered to be the final pathway leading to the progressive loss of renal function in several kidney diseases, transforming growth factor β1 (TGF-β1) plays a critical role in glomerulosclerosis. However, the mechanisms of TGF-β1 stimulating glomerulosclerosis remain poorly understood. Here we report that TGF-β1-induced expression of fibronectin (FN) depends on the activity of aldose reductase (AR) in human mesangial cells (HMCs).The results show that TGF-β1 increased the expression of FN, which attenuated by pharmacological inhibition of AR or knockdown of the enzyme by small interfering RNA (siRNA). MAPKs (ERK, JNK and p38) signalling pathways were activated in HMCs after stimulated by TGF-β1, inhibition of AR blunted the activation ERK, p38 and JNK signalling pathways. These changes were associated with decreased TGF-β1-induced expression of FN. These results indicate that AR is a potent regulator of TGF-β1 induced expression of FN in human mesangial cells: it suggests that inhibition of this enzyme may be useful to prevented extracellular matrix (ECM) deposition in glomerulosclerosis.     

Review: Clinical Management of Helicobacter pylori Infection in China

Helicobacter pylori (H. pylori) infection has been associated with gastric disorders. The situation of H. pylori infection in China—where a high prevalence of H. pylori infection, a high incidence of gastric cancer, and widespread resistance to clarithromycin, metronidazole, and levofloxacin exist—is quite different from that in Western countries. In order for Chinese clinicians to better manage H. pylori infection, a Chinese Study Group on H. pylori published four consensus reports regarding the management of H. pylori infection in China between 1999 and 2012. The eradication rate with standard triple therapy was <80% in most areas of China. Bismuth is available in China, and bismuth‐containing quadruple therapy has been shown to produce a high eradication rate; thus, bismuth quadruple therapy could be recommended both as an initial and as a rescue therapy in China. There is no advantage of sequential therapy over triple therapy in Chinese patients, but the efficacy of concomitant therapy must be studied further. This review introduces the epidemiology, diagnosis, indicators, and therapies for the eradication of H. pylori in China in recent years.     

Laboratory evaluation of entomopathogenic fungi against the white grubs,Holotrichia oblita and Anomala corpulenta (Coleoptera: Scarabaeidae) from the field of peanut,Arachis hypogaea

We evaluated the pathogenicity of nine isolates of entomopathogenic fungi, including six isolates of Metarhizium anisopliae, one of Beauveria bassiana, and two of Beauveria brongniartii, against eggs and various larval instars of two scarab-beetle species, Holotrichia oblita and Anomala corpulenta, under laboratory conditions. The fungal isolates differed in pathogenicity. Generally, the isolates were more pathogenic to A. corpulenta than to H. oblita. Some of the isolates prevented egg hatching and caused larval death. Isolates M2-2 and Br5-8 caused 39 and 27% egg mortality, respectively, and produced 23 and 24% viewable fungal-infection rates in H. oblita. Three isolates had no significant effect on egg hatchability. Three isolates (Br5-8, Br232818, and M200614) caused about 40% mortality in H. oblita first instars. In A. corpulenta, all isolates except M200614 caused more than 60% egg mortality, and M2-2, Br232818 and Br5-8 caused egg-infection rates greater than 50%. M2-2 caused 47% infection and 100% mortality in first-instar larvae of A. corpulenta, while Br5-8 and Br232818 yielded over 80% mortality of the larvae. The three most virulent isolates, M2-2, Br232818 and Br5-8, were selected for further bioassays against second- and third-instar larvae. In addition, seven graduated concentrations of a Br5-8 conidial suspension were assayed against H. oblita second instars. Larval mortality was positively correlated with fungal dosage, and the LC₅₀ was 4.49×10⁶ conidia/mL. These three virulent isolates may be used to prevent H. oblita and A. corpulenta larval infestations in field crops.     

Capillary electrophoresis analysis of mangiferin extracted from Mangifera indica L. bark and Mangifera persiciformis C.Y. Wu et T.L. Ming leaves

The flavonoid compound mangiferin is found in the leaves, stem bark, fruit peels and root of Mangifera indica L. and in many other herbal species with many potential pharmacological properties. We have established an analytical method of mangiferin extracted from M. indica L. bark and Mangifera persiciformis C.Y. Wu et T.L. Ming leaves utilizing CZE. An electrolytic buffer containing 0.05 M borate buffer, pH 7.4 with methanol (1:0.3, v/v) was deemed suitable for mangiferin analysis. An ideal mangiferin electropherogram with a migration time at approximately 10.50 min was obtained. Repeatability tests showed that the R.S.D.s for both intra- and inter-day migration time and peak area for all manigferin sources tested were less than 4%. The linearity range of this method was 5-1000 microg/ml. The detection limit of this method was 1.5 microg/ml. Quantitative analysis of mangiferin was also performed with this method. The accuracy of quantitation at 10, 500 and 1000 microg/ml of control mangiferin were 99.00, 99.38 and 99.14%, respectively (n=10). The repeatability of quantitation (R.S.D.) was below 3%. Our results demonstrated that CZE is a simple and reliable method in mangiferin analysis and more studies are needed to detect other mangiferin resources, such as clinical biological samples, in pharmacology and pharmacokinetic studies.