First Report of Fusarium Head Blight of Wheat Caused by Fusarium sacchari in China.

Fusarium head blight (FHB), or scab, caused by Fusarium species, is an economically devastating disease of wheat and other cereal crops worldwide. FHB epidemics in wheat occur frequently in China, especially along the middle and lower reaches of the Yangtze River, including Jiangsu and Shanghai. In 2013, wheat spikes showing clear FHB symptoms were collected from fields in Jiangsu and Shanghai. Symptomatic seeds were surface-sterilized for 1 min with a 5% sodium hypochlorite solution and dipping in 70% ethanol for 30 s, then rinsed three times in sterile distilled water and dried. They were placed onto potato dextrose agar (PDA) and incubated for 3 to 5 days at 28°C in the dark. Fungal colonies displaying morphological characteristics of Fusarium spp. (1,2) were purified by the single-spore technique and characterized at the species level by morphological observations (1,2) and translation elongation factor 1-α (TEF) gene sequencing. The results indicated that members of the Fusarium graminearum clade were predominant on wheat, while the morphological characteristics of 16 isolates were found to be identical to those of F. sacchari (1,2). Colonies on PDA were densely cottony, initially pale but becoming violet with age. The average growth rate was 6 to 8 mm per day at 25°C in the dark. Reverse pigmentation was brownish red to violet-brown. Microconidia, abundant in the aerial mycelium and formed in false heads, were oval to ellipsoidal in shape, primarily zero-septate, measuring 5.7 to 18.8 (average 10.6) µm in length. Macroconidia were slender, three- to five-septate, with a curved apical cell and a poorly developed basal cell, 26.3 to 68.9 (average 44.0) µm in length. No chlamydospores were observed. Two F. sacchari strains (Y37 and S43), isolated from Jiangsu and Shanghai, respectively, were investigated by sequence comparison of their partial TEF gene sequences (Accession Nos. KM233195 and KM233196). BLASTn analysis of the TEF sequences obtained with sequences available in the GenBank database revealed 99.8 and 99.5% sequence identity to F. sacchari (GenBank Accession Nos. JF740708 and JF740709). Pathogenicity tests were conducted by injecting 10 µl of a spore suspension (5 × 105 spores/ml) into wheat florets (20 per isolate of cv. Yangmai16), which were then grown under field conditions in Shanghai. Control plants were inoculated with sterile distilled water. Spikes were harvested and evaluated 14 days post-inoculation. Reddish white mold was observed on inoculated wheat spikes; in addition, spikelets adjacent to the inoculation point and the infected florets were brown. No symptoms were observed on water controls. Koch's postulates were fulfilled by reisolating the pathogen from infected florets and identifying them by TEF gene sequencing. F. sacchari is the cause of an important disease of sugar cane, pokkah boeng (1), and has been reported to produce the mycotoxin beauvericin, which causes toxicosis in human and other animals (3). To our knowledge, this is the first report of F. sacchari causing wheat head blight in China. The report contributes to an improved understanding of the composition of Fusarium species on wheat in the lower reaches of the Yangtze River in China, which will be useful for exploring appropriate disease management strategies in this region. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (2) J. F. Leslie et al. Mycologia 97:718, 2005. (3) A. Moretti et al. Int. J. Food Microbiol. 118:158, 2007.

First Report of Corn Kernel Brown Spot Disease Caused by Mucor irregularis in China.

In October 2012, a brown spot disease was found on corn kernels during a field survey in Nanyang city (33°01' N, 112°29' E), China. The incidences of affected ears and kernels were 2 to 10% (n = 600) and 0.08 to 0.4% (n = 25,000), respectively. Symptoms first appeared as circular or irregular brown spots on the endosperm. These spots subsequently enlarged or coalesced, resulting in the formation of a large light-brown or light-yellow irregular speckle commonly surrounded by a dark-brown edge. Pure fungal cultures with similar morphological characteristics were obtained from surface-disinfected symptomatic kernels using a conventional method for isolation of culturable microbes. The isolated fungal cultures were purified by single-spore isolation (3). A representative isolate F1 was randomly selected, used for pathogenicity tests, and identified using morphological and molecular methods. Colonies on PDA were circular with abundant villiform aerial mycelia. The color of colonies was white-gray at first and turned to light yellow or became ochraceous after 3 days of incubation at 28°C. Hyphae were hyaline and less septate, with rectangular branches. Sporangiophores were erect and unbranched or branched, with globose sporangia formed on their tips. Sporangiospores were elliptical to round, 3.6 to 7.3 × 1.6 to 3.7 µm (n = 100) in size. Two gene regions were amplified for multilocus sequence typing. The D1/D2 region of the nuclear large subunit ribosomal RNA gene (nucLSU) was amplified with primers NL1 and NL4 and the rDNA internal transcribed spacer (ITS) with primers ITS1 and ITS4. PCR products were purified using an Axygen nucleic acid purification kit for sequencing. Both rDNA D1/D2 and rDNA-ITS sequences were submitted to GenBank with accession numbers KM093834 and KM203872, respectively. The isolate F1 showed 98% identity with two isolates of Mucor irregularis (KC524427 and KC461926) in rDNA-ITS sequences and 99% identity with multiple isolates (JX976221, JX976203, and JX976219) of M. irregularis in rDNA D1/D2 sequences. Pathogenicity tests of isolate F1 were conducted based on Koch's postulates. Thirty kernels of fresh ears (milk stage) were pricked by sterilized toothpicks and separately inoculated with a sporangiospore suspension (1 × 106 spores/ml) and 5-day-old mycelial plugs (5 × 5 mm) of isolate F1. Kernels on ears that were inoculated with sterilized water and pure PDA plugs were separately used as controls. After 7 days of incubation, brown spot symptoms developed on the F1-inoculated kernels, which were similar to those observed on the naturally infected ears from the field samples. The control ears remained symptomless during the inoculation tests. Fungal cultures showing the same morphological characteristics as those of isolate F1 were consistently recovered from the diseased cobs inoculated by isolate F1, indicating that M. irregularis was responsible for corn kernel brown spot disease. M. irregularis was reported as a pathogen causing human skin diseases in China (5), America (1), and India (2) and as a phytopathogen causing fruit rot on durian (4). This is the first report of M. irregularis causing corn kernel brown spot disease in China. References: (1) M. M. Abuali et al. J. Clin. Microbiol. 47:4176, 2009. (2) B. M. Hemashettar et al. J. Clin. Microbiol. 49:2372, 2011. (3) S. L. Huang and K. Kohmoto. Bull. Fac. Agric., Tottori Univ. 44:1, 1991. (4) W. F. Wang et al. Plant Quarant. l23:60, 2009. (5) Y. Zhao et al. Mycopathologia 168:243, 2009.

Association between ARNTL (BMAL1) rs2278749 polymorphism T >C and susceptibility to Alzheimer disease in a Chinese population.

In the present study, we examined whether the ARNTL (BMAL1) rs2278749 T/C polymorphism was associated with the susceptibility to Alzheimer disease (AD). This case-control study examined the genotypes of apolipoprotein E (APOE e4) and BMAL1 rs2278749 T/C using restriction fragment length polymorphism and the TaqMan assay, respectively. A total of 296 unrelated AD patients and 423 control subjects were included. Both in the entire sample and in APOE e4 non-carriers, the prevalence of T carriers in BMAL1 rs2278749 T/C in AD patients was significantly higher than that in control subjects (entire sample: χ(2) = 12.950, P < 0.0001; APOE e4 non-carriers: χ(2) = 13.094, P < 0.0001). Both in the entire sample and in APOE e4 non-carriers, the prevalence of TT genotypes 2278749 in AD patients was also significantly higher than that in control subjects (entire sample: χ(2) = 7.765, P = 0.024; APOE e4 non-carriers: χ(2) = 13.062, P < 0.0001). However, among APOE e4 carriers, the difference in the prevalence of T carriers or TT genotypes in the BMAL1 rs2278749 T/C between patients and control subjects presents was not significant (T carriers: χ(2) = 0.078, P = 0.851 or TT genotypes: χ(2) = 2.576, P = 0.325). Among APOE e4 non-carriers, T carriers in the BMAL1 rs2278749 T/C were associated with a high susceptibility to AD, but among APOE e4 carriers, the association between AD and BMAL1 rs2278749 T/C was not significant.

Adiponectin is expressed in the pancreas of high-fat-diet-fed mice and protects pancreatic endothelial function during the development of type 2 diabetes.

AIM: Adiponectin levels in skeletal muscle and adipose tissue have been reported to be involved in insulin resistance in rats fed with a high-fat diet (HFD). Our objective was to explore whether adiponectin is also expressed in the pancreas and what its potential role is during the development of type 2 diabetes (T2D) in outbred CD-1 mice. METHODS: Male 4-week-old outbred CD-1 mice were fed an HFD to induce a polygenic model of human T2D. Adiponectin expression was examined in mouse pancreas by quantitative real-time polymerase chain reaction (qPCR), western blots and immunofluorescence analyses. Human umbilical vein endothelium cells (HUVECs) were transfected with an adiponectin-expressing lentivirus to determine the effect of adiponectin on angiogenic function in vitro. RESULTS: Feeding mice an HFD for 9weeks resulted in constant hyperglycaemia, obesity, impaired glucose tolerance and insulin resistance. Additional hyperinsulinaemia emerged in mice fed an HFD for 18weeks. Interestingly, aberrant expression of adiponectin was detectable in the pancreatic vascular endothelial cells (VECs) of mice fed with an HFD, but not in mice fed with regular chow (RC). Expression levels of pancreatic adiponectin varied during the development of T2D. This extraordinary expression of adiponectin in pancreatic VECs played a role in protecting endothelial function against potential damage by HFD. Our in vitro study has demonstrated that adiponectin promotes angiogenic function. CONCLUSION: These results reveal for the first time that adiponectin is expressed in pancreatic VECs of HFD-fed mice during the development of T2D as a protective adaptation in response to the HFD.

The effect Akt2 deletion on tumor development in Pten(+/-) mice.

The serine/threonine kinase Akt is frequently activated in human cancers and is considered an attractive therapeutic target. However, the relative contributions of the different Akt isoforms to tumorigenesis, and the effect of their deficiencies on cancer development are not well understood. We had previously shown that Akt1 deficiency is sufficient to markedly reduce the incidence of tumors in Pten(+/-) mice. Particularly, Akt1 deficiency inhibits endometrial carcinoma and prostate neoplasia in Pten(+/-) mice. Here, we analyzed the effect of Akt2 deficiency on the incidence of tumors in Pten(+/-) mice. Relative to Akt1, Akt2 deficiency had little-to-no effect on the incidence of prostate neoplasia, endometrial carcinoma, intestinal polyps and adrenal lesions in Pten(+/-) mice. However, Akt2 deficiency significantly decreased the incidence of thyroid tumors in Pten(+/-), which correlates with the relatively high level of Akt2 expression in the thyroid. Thus, unlike Akt1 deletion, Akt2 deletion is not sufficient to markedly inhibit tumorigenesis in Pten(+/-) mice in most tested tissues. The relatively small effect of Akt2 deletion on the inhibition of tumorigenesis in Pten(+/-) mice could be explained, in part, by an insufficient decrease in total Akt activity, due to the relatively lower Akt2 versus Akt1 expression, and relatively high blood insulin levels in Pten(+/-)Akt2(-/-) mice. The relatively high blood insulin levels in Pten(+/-)Akt2(-/-) mice may elevate the activity of Akt1, and possibly Akt3, thus, limiting the reduction of total Akt activity and preventing this activity from dropping to a threshold level required to inhibit tumorigenesis.

Cognitive behavioural therapy and reminiscence techniques for the treatment of depression in the elderly: a systematic review.

Psychotherapy, including cognitive behavioural therapy (CBT), reminiscence and general psychotherapy (GPT), is viewed as effective treatment for depression, but its efficacy in older people is not well defined. This systematic review included 14 randomized controlled trials that assessed the efficacy of psychotherapy for treating depression in elderly people (> or = 55 years). The results of this meta-analysis showed that, compared with placebo, psychotherapy was more effective in reducing depression scores (standardized mean difference -0.92; 95% confidence interval -1.21, -0.36). Subgroup analysis showed that CBT, reminiscence and GPT were all more effective than placebo; psychotherapy as an adjunct to antidepressant medication did not increase effectiveness. There was no significant difference between CBT and reminiscence in improving depression. A higher drop-out rate was observed in studies that did not include psychotherapy versus those that did, although this difference was not statistically significant. Thus, various general formats of psychotherapy are effective for treating depression in older people, although psychotherapy does not significantly increase the effectiveness of anti-depressant medication.

Homologous and heterologous in vitro regulation of pig pituitary somatostatin receptor subtypes, sst1, sst2 and sst5 mRNA.

Somatostatin (SRIF) is commonly regarded as an inhibitor of GH release in rodents and humans. However, in pigs, SRIF can stimulate the release of GH at low (picomolar) doses, while inhibiting GHRH-stimulated GH release at high (nanomolar) doses in primary pituitary cell cultures. One possible mechanism by which pig cells respond differently to the actions of SRIF is by differential expression and regulation of SRIF receptor subtypes. As no information is available on the homologous regulation of SRIF receptors in pigs, we examined the acute (4 h) in vitro effects of SRIF on mRNA levels of SRIF receptors sst1, sst2 and sst5 by multiplex RT-PCR. These particular sst subtypes were selected because all three have been implicated in the inhibitory effects of SRIF on GH release in both rodents and humans. At a high dose (10(-7) M), SRIF stimulated the expression of sst1, sst2 and sst5 in pig pituitary cell cultures. At a low dose (10(-13) M), SRIF markedly increased sst1, without affecting sst2 or sst5. Given that our laboratory has shown SRIF at high and low doses stimulates cAMP production in a subpopulation of pig somatotropes, we sought to determine if this signaling pathway may be responsible for the stimulatory effect of SRIF on its own receptor expression. The receptor-independent cAMP activator forskolin elevated sst1 and sst2 mRNA levels but did not affect sst5 expression, suggesting the stimulatory actions of high- and low-dose SRIF on sst1 and high-dose SRIF on sst2 mRNA levels can be mediated by activation of cAMP, whereas the stimulatory effect of high-dose SRIF on sst5 mRNA is elicited by a cAMP-independent pathway. Interestingly, both GHRH (10(-8) M) and ghrelin (10(-6) M), which release GH in pig pituitary cell cultures via cAMP-dependent mechanisms, decreased sst5 without altering sst1 or sst2 mRNA levels. Since the actions of GHRH and ghrelin on sst expression markedly contrasted with that observed for SRIF and forskolin these results clearly indicate GHRH and ghrelin are regulating sst5 mRNA levels by a cAMP-independent signaling pathway. Taken together, our results demonstrate that expression of pig SRIF receptors is under a complex, receptor subtype-selective regulation, wherein the concerted actions of key regulators of somatotrope function would play divergent and dose-dependent effects.

Liver-derived IGF-I regulates GH secretion at the pituitary level in mice.

We have reported that liver-specific deletion of IGF-I in mice (LI-IGF-I-/-) results in decreased circulating IGF-I and increased GH levels. In the present study, we determined how elimination of hepatic IGF-I modifies the hypothalamic-pituitary GH axis to enhance GH secretion. The pituitary mRNA levels of GH releasing factor (GHRF) receptor and GH secretagogue (GHS) receptor were increased in LI-IGF-I-/- mice, and in line with this, their GH response to ip injections of GHRF and GHS was increased. Expression of mRNA for pituitary somatostatin receptors, hypothalamic GHRF, somatostatin, and neuropeptide Y was not altered in LI-IGF-I-/- mice, whereas hypothalamic IGF-I expression was increased. Changes in hepatic expression of major urinary protein and the PRL receptor in male LI-IGF-I-/- mice indicated an altered GH release pattern most consistent with enhanced GH trough levels. Liver weight was enhanced in LI-IGF-I-/- mice of both genders. In conclusion, loss of liver-derived IGF-I enhances GH release by increasing expression of pituitary GHRF and GHS receptors. The enhanced GH release in turn affects several liver parameters, in line with the existence of a pituitary-liver axis.

p27Kip1-deficient mice exhibit accelerated growth hormone-releasing hormone (GHRH)-induced somatotrope proliferation and adenoma formation.

p27Kip1 (p27) controls cell cycle progression by binding to and inhibiting the activity of cyclin dependent kinases. Disruption of the p27 gene in mice (p27-/-) results in increased body growth with a disproportionate enlargement of the spleen, thymus, testis, ovary and pituitary. The increase in pituitary size is due to selective hyperplasia of the intermediate lobe (IL) while the anterior lobe (AL) is not overtly affected. p27 heterozygous mice (p27+/-), as well as p27-/- mice, are hypersensitive to radiation- and chemical-induced tumors compared to wildtype (p27+/+) littermates. Therefore, unlike classical tumor suppressors, only a reduction in p27 levels is necessary to predispose tissues to secondary tumor promoters. Consistent with these studies is the fact that the p27 gene sequence and mRNA levels appear normal in human pituitary adenomas while p27 protein levels are decreased. Therefore, a reduction in p27 levels could be sufficient to sensitize pituitary cells to tumorigenic factors. To test this hypothesis, metallothionein promoter-driven, human growth hormone-releasing hormone (MT-hGHRH) transgenic mice, that exhibit somatotrope hyperplasia before 9 months of age and subsequent adenoma formation with 30 - 40% penetrance, were crossbred with p27+/- mice for two successive generations to produce p27+/+, p27+/- and p27-/- mice that expressed the hGHRH transgene. At 10 - 12 weeks of age, p27-/- and p27+/+, hGHRH mice were larger than their p27+/+ littermates and displayed characteristic hyperplasia of the IL and AL, respectively. Expression of the hGHRH transgene in both p27+/- and p27-/- mice selectively expanded the population of somatotropes within the AL, where pituitaries of p27+/-, hGHRH and p27-/-, hGHRH mice were two- and fivefold larger than p27+/+, hGHRH pituitaries, respectively. There was also a synergistic effect of hGHRH transgene expression and p27-deficiency on liver, spleen and ovarian growth. At 6 - 8 months of age, 83% of p27+/-, hGHRH mice displayed macroscopic AL adenomas (>100 mg), while all pituitaries from p27+/+, hGHRH mice remained hyperplastic (<20 mg). In contrast to the dramatic effects of p27-deficiency on hGHRH-induced organ growth, elimination of p53, by crossbreeding MT-hGHRH mice to p53-deficient mice, did not augment the hyperplastic/tumorigenic effects of hGHRH transgene expression. Taken together these results demonstrate that a reduction in p27 expression is sufficient to sensitize somatotropes to the proliferative actions of excess GHRH, resulting in the earlier appearance and increased penetrance of hGHRH-induced pituitary tumors.