An Outbreak of Head Rot of Cabbage Caused by Rhizoctonia solani AG2-1 in Central China

In July of 2007, an outbreak of head rot of cabbage (Brassica oleracea) occurred on more than 2,500 ha in Changyang County, Hubei Province, China. On average, yields were reduced by approximately 50%. Affected plants were first observed in 2006, and symptoms were considered physiological or nutritional disorders by growers. In 2007, the more extensive summer rains favored an increase in disease severity. Initial symptoms consisted of irregular, brown-to-black lesions on leaves and sometimes a wet decay of the base of outer leaves. Lesions expanded until entire heads were rotted. Rhizoctonia solani was recovered consistently from symptomatic plant tissues. Five isolates were used to evaluate cultural and morphological characteristics of the pathogen. On potato dextrose agar (PDA), all isolates yielded colonies that became brown after 5 days of incubation. The hyphae, 4.9 to 8.0 μm in diameter, branched at right or acute angles near the septa and each cell usually had six to eight nuclei. Dark brown sclerotia, 0.5 to 5 mm in diameter, appeared after 10 days of incubation. Genomic DNA of a representative isolate, CY-1, was extracted, and the rDNA-internal transcribed spacer sequence showed 99.5% identity to R. solani AG2-1 (Accession No. EU513147) in GenBank. Pathogenicity tests were completed in the laboratory by placing 6-mm-diameter mycelial plugs from 3-day-old PDA cultures of the five isolates onto 30 cabbage leaves detached from 5-week-old cabbage plants. The inoculated leaves were incubated at 28°C with 95% relative humidity in a controlled environment chamber. Two days after inoculation, black, wet lesions were observed on all inoculated leaves, while no symptoms were apparent on leaves inoculated with noncolonized PDA plugs. Koch's postulates were fulfilled by reisolating R. solani from diseased leaves. R. solani AG1 (1), AG2-1 (2), and AG4 (4) have been reported as causal agents of diseases of cabbage and related plants, and AG2-1 has been previously isolated from cabbage grown in southwest China (3), but to our knowledge, this is the most severe outbreak reported from China. References: (1) G. S. Abawi and S. B. Martin. Plant Dis. 69:158, 1985. (2) L. Corazza et al. Eur. J. Plant Pathol. 101:341, 1995. (3) H. R. Li and H. H. Zhu. J. Yunnan Agric. Univ. 3:247, 1993. (4) G. H. Yang et al. Plant Pathol. 56:351, 2007.

Investigating lipid-lipid and lipid-protein interactions in model membranes by ToF-SIMS

With the chemical imaging capability of ToF-SIMS, biological molecules are identified and localized in membranes without any chemical labels. We have developed a model membrane system made with supported Langmuir-Blodgett (LB) monolayers. This simplified model can be used with different combinations of molecules to form a membrane, and thus represents a bottom-up approach to study individual lipid-lipid or lipid-protein interactions. We have used ternary mixtures of sphingomyelin (SM), phosphatidylcholine (PC), and cholesterol (CH) in the model membrane to study the mechanism of domain formation and interactions between phospholipids and cholesterol. Domain structures are observed only when the acyl chain saturation is different for SM and PC in the mixture. The saturated lipid, whether it is SM or PC, is found to be localized with cholesterol, while the unsaturated one is excluded from the domain area. More complicated model membranes which involve a functional membrane protein glycophorin are also investigated and different membrane properties are observed compared to the systems without glycophorin.

A chemometric study of chromatograms of tea extracts by correlation optimization warping in conjunction with PCA, support vector machines and random forest data modeling

A reverse phase high performance liquid chromatography (HPLC) separation was established for profiling water soluble compounds in extracts from tea. Whole chromatograms were pre-processed by techniques including baseline correction, binning and normalisation. In addition, peak alignment by correction of retention time shifts was performed using correlation optimization warping (COW) producing a correlation score of 0.96. To extract the chemically relevant information from the data, a variety of chemometric approaches were employed. Principle component analysis (PCA) was used to group the tea samples according to their chromatographic differences. Three principal components (PCs) described 78% of the total variance after peak alignment (64% before) and analysis of the score and loading plots provided insight into the main chemical differences between the samples. Finally, PCA, support vector machines (SVMs) and random forest (RF) machine learning methods were evaluated comparatively on their ability to predict unknown tea samples using models constructed from a predetermined training set. The best predictions of identity were obtained by using RF.

A rete mirabile of the posterior cerebral artery. Embryonic and phylogenetic remnant of choroidal artery origin

SUMMARY

We present the case of a 41-year-old man with a vascular network associated with the left posterior cerebral artery (PCA). Although initially considered to be a brain AVM, further investigation showed no arteriovenous shunting and a rete mirabile of the PCA was diagnosed. A well known but rare occurrence mainly in the anterior circulation, rete mirabile has not previously been described in the PCA.The PCA is a composite vessel, developmentally. Its proximal portion derives from the posterior division of the ICA while its cortical territories are annexed from the anterior choroidal artery adjacent to the lateral geniculate body. We propose that this rete (or network) represents a persistence of the embryonic anastomosis betweenthe AChA and the PCA.

Prevalence of and risk factors for isolated systolic hypertension in the rural adult population of Liaoning Province, China

The prevalence of and associated risk factors for isolated systolic hypertension, as defined by the Joint National Committee (JNC)-6 classification, were investigated in the rural population of Liaoning Province, China. A total of 45,925 people aged 35 years or older were examined in a cross-sectional study. Overall, the prevalence of isolated systolic hypertension was 10.6% (males 10.1%; females 11.2%). The prevalence of isolated systolic hypertension was positively correlated with age, gender, smoking status, alcohol intake, body mass index, salt intake and Mongolian race. This study showed that isolated systolic hypertension was very common in rural Chinese people and that many risk factors are linked with isolated systolic hypertension.

Expression of anion exchanger 2 in human gastric cancer

Anion exchanger 2 (AE2), which mediates exchange of Cl(-)/HCO3(-) across the plasma membrane, is widely expressed in body tissues. It is most abundantly expressed in stomach and is responsible for the uptake of Cl(-) ions that are destined to become HCl molecules.

AIM

To determine whether AE2 expression was altered in gastric tumors.

METHODS

We have studied AE2 expression in normal human gastric tissues (n =16) and in gastric tumors (n = 33) using immunohistochemistry and immunofluorescent labeling.

RESULTS

In normal gastric tissue positive staining was observed in gastric fundus gland, suggesting parietal cell-related expression of AE2, and AE2 expression was localized in the nuclear membrane and even in cell nuclei. For assay of cancerous gastric tissues, specimens of human gastric cancer arising from the region of the fundus (2 cases), the body (14 cases) and the antrum (17 cases) were randomly selected. Immunohistochemical staining has showed that AE2 was down-regulated in all 14 cancerous gastric body specimens, whereas staining for AE2 in cancerous antrum was less intense and had a diffuse profile.

CONCLUSIONS

The data suggest that AE2 might be associated with gastric carcinogenesis and the achlorhydria experienced by gastric cancer patients.

Altered hippocampal circuit function in C3H alpha7 null mutant heterozygous mice

The alpha7 subtype of nicotinic receptor is highly expressed in the hippocampus where it is purported to modulate release of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The alpha7 receptor-mediated release of GABA is thought to contribute to hippocampal inhibition (gating) of response to repetitive auditory stimulation. This hypothesis is supported by observations of hippocampal auditory gating deficits in mouse strains with low levels of hippocampal alpha7 receptors compared to strains with high levels of hippocampal alpha7 receptors. The difficulty with comparisons between mouse strains, however, is that different strains have different genetic backgrounds. Thus, the observed interstrain differences in hippocampal auditory gating might result from factors other than interstrain variations in the density of hippocampal alpha7 receptors. To address this issue, hippocampal binding of the alpha7 receptor-selective antagonist alpha-bungarotoxin as well as hippocampal auditory gating characteristics were compared in C3H wild type and C3H alpha7 receptor null mutant heterozygous mice. The C3H alpha7 heterozygous mice exhibited significant reductions in hippocampal alpha7 receptor levels and abnormal hippocampal auditory gating compared to the C3H wild type mice. In addition, a general increase in CA3 pyramidal neuron responsivity was observed in the heterozygous mice compared to the wild type mice. These data suggest that decreasing hippocampal alpha7 receptor density results in a profound alteration in hippocampal circuit function.

Prevalence of metabolic syndrome in Han and Mongolian rural population with hypertension

The prevalence of metabolic syndrome, as defined by the International Diabetes Federation, was compared in two rural populations with hypertension in China. A total of 6326 subjects aged >or= 35 years were included: 5043 Han and 1283 Mongolian. Metabolic syndrome was identified in 33.9% (men: 16.1%; women: 47.8%) of the Han and 37.6% (men: 14.7%; women: 55.0%) of the Mongolian populations. In men, prevalence of metabolic syndrome showed no obvious ethnicity differences; however, in women, prevalence was significantly higher in the Mongolian than in the Han population. This study showed high prevalence and ethnic differences in prevalence of metabolic syndrome in these two Chinese hypertensive populations.

Critical role of inducible nitric oxide synthase in degeneration of retinal capillaries in mice with streptozotocin-induced diabetes

AIMS/HYPOTHESIS

Diabetes results in the upregulation of the production of several components of the inflammatory response in the retina, including inducible nitric oxide synthase (iNOS). The aim of this study was to investigate the role of iNOS in the pathogenesis of the early stages of diabetic retinopathy using iNOS-deficient mice (iNos (-/-)).

MATERIALS AND METHODS

iNos (-/-) mice and wild-type (WT; C57BL/6J) mice were made diabetic with streptozotocin or kept as non-diabetic controls. Mice were killed at different time points after the induction of diabetes for assessment of vascular histopathology, cell loss in the ganglion cell layer (GCL), retinal thickness, and biochemical and physiological abnormalities.

RESULTS

The concentrations of nitric oxide, nitration of proteins, poly(ADP-ribose) (PAR)-modified proteins, endothelial nitric oxide synthase, prostaglandin E(2), superoxide and leucostasis were significantly (p < 0.05) increased in retinas of WT mice diabetic for 2 months compared with non-diabetic WT mice. All of these abnormalities except PAR-modified proteins in retinas were inhibited (p < 0.05) in diabetic iNos (-/-) mice. The number of acellular capillaries and pericyte ghosts was significantly increased in retinas from WT mice diabetic for 9 months compared with non-diabetic WT controls, these increases being significantly inhibited in diabetic iNos (-/-) mice (p < 0.05 for all). Retinas from WT diabetic mice were significantly thinner than those from their non-diabetic controls, whereas diabetic iNos (-/-) mice were protected from this abnormality. We found no evidence of cell loss in the GCL of diabetic WT or iNos (-/-) mice. Deletion of iNos had no beneficial effect on diabetes-induced abnormalities on the electroretinogram.

CONCLUSIONS/INTERPRETATION

We demonstrate that the inflammatory enzyme iNOS plays an important role in the pathogenesis of vascular lesions characteristic of the early stages of diabetic retinopathy in mice.

A phase II trial of weekly cisplatin and docetaxel in advanced non-small cell lung cancer (NSCLC)

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Background: Every 3-week cisplatin doublets used to treat advanced NSCLC carry a significant risk of renal and other toxicities and can be difficult for patients with co-morbidities. To reduce these toxicities, we conducted a phase II study to evaluate the efficacy and toxicity of weekly cisplatin and docetaxel in advanced NSCLC. Methods: Eligibility included patients with advanced or recurrent NSCLC, ECOG PS of 0–1, and no prior chemotherapy for metastatic disease. This Cancer Institute of New Jersey network, single stage phase II clinical trial was designed to give 3 weekly doses of cisplatin at 25 mg/m2 and docetaxel at 35 mg/m2, followed by 1 week of rest, for a total of 6 cycles of therapy. Toxicity was monitored weekly, and disease evaluation was performed every 2 cycles. The primary endpoint was response rate (RR); secondary endpoints included time to progression (TTP), median and 1-year survival. Results: From 12/03 to 11/06, 36 patients were enrolled so far. The median age of patients is 63 (range 47–78), the majority is white (n=33), 29 have stage IV disease, and half (n=18) are women. Fourteen have an ECOG PS=0 and 22 with PS=1. Histologic subtypes are: adenocarcinoma (n=24), NSCLC NOS (n=7), squamous (n=5). Eleven patients received = 4 cycles of therapy; median number of cycles delivered is 2.5. Reasons for treatment discontinuation include completion of therapy (n=5), progression of disease (n=16), adverse events (n=8), and patient preference (n=4). Three patients continue on therapy at this time. No complete responses were yet observed; 8 patients (22%) achieved a partial response; 10 patients had stable disease, 10 patients progressed, and 8 came off study before first disease evaluation. Median TTP was 3.1 months (mo) (95% CI 2, 5.5), median survival is 8.3 mo (95% CI 5,16.2) and 1-year survival is 39% (95% CI 20, 57). Most toxicities were mild but also included neutropenia (grade 3, n=1; grade 4, n=1), neutropenic fever (n=1), renal toxicity (grade 3, n=2), nausea (grade 3, n=1), fatigue (grade 3, n=3), diarrhea (grade 3, n=4) and metabolic abnormalities (grade 3, n=3). Conclusion: Weekly cisplatin and docetaxel is well tolerated with a low incidence of toxicity and demonstrates activity similar to every 3-week treatment in patients with advanced NSCLC.

No significant financial relationships to disclose.

Randomized multicenter phase III trial of oxaliplatin plus raltitrexed compared to oxaliplatin plus fluorouracil and leucovorin treatment in recurrent and metastatic colorectal cancer

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Purpose: To compare oxaliplatin (L-OHP) plus raltitrexed (RTX) with L-OHP plus fluorouracil and leucovorin (LV/5FU) for patients (pts) with recurrent and metastatic colorectal cancer(CRC). Methods: Eligible pts had to have histologically proven recurrent or metastatic CRC,not having previously received oxaliplatin as palliative chemotherapy,ECOG PS = 2,age:18∼70,and adequate hematological,renal and hepatic function.After written informed consent,pts were randomized to L-OHP:130 mg/m2 d1 + RTX: 3 mg/m2 d1 (Arm A) or + LV: 200 mg/m2 + 5FU:375 mg/m2 d1–5 (Arm B). Results: Between Jan 2005 and July 2006, 216 pts were enrolled at 15 centers in China.112 pts (mean age: 55.0 (19∼70), M/F: 57/46, PS 0/1/2: 46/53/13) were randomly assigned to A and 102 (mean age: 54.2(22∼70), M/F: 54/46, PS 0/1/2: 44/59/9) to B. 203 pts were eligible for response evaluation (A:103, B:100).The median number of cycles was 4 (1∼6) in A and 3 (1∼6) in B (P=0.1431).The RR was 29.1% (CR:2, PR:28, SD:50 , PD:23) in A and 17.0% (CR:2, PR:15, SD:46 , PD:37) in B (P=0.0437).The disease-control rate was 77.7% in A and 63.0% in B (P=0.0237). After a median follow-up of 10 months (4–16.5),92 pts had had progression of disease (40 in A and 52 in B); 73 deaths had occurred (35 in A and 38 in B), median time to progression was not reached. Following-up is ongoing.The median QoL scores for the two arms were comparable. 214 were included in the safety analyses (A:112, B:102). There was a higher incidence of neutropenia (48.2% verse 29.4%, P=0.005) and transaminase increase (49.1% verse 35.3%, P=0.041) among A. Grade 3 or 4 neutropenia was much common in pts in A than those in B (20.5% verse 4.9% , P=0.001), but was complicated by fever in only 3.6% of cases (4 pts) in A and in 2.9% of cases (3 pts) in B. No pts were dead or infectious due to neutropenia. There were similar rates of grade 3 or 4 transaminase elevation in the two groups. Vomitting and anorexia were much commoner with B. Conclusions: The L-OHP+RTX seems beneficial in recurrent and metastatic CRC, demonstrating better response rate and higher disease control rate with acceptable tolerability, maintenance of QoL and convenient administration schedule.

No significant financial relationships to disclose.

Construction of a counterselection-based in-frame deletion system for genetic studies of Streptococcus mutans

Genetic studies of Streptococcus mutans have benefited greatly from the numerous techniques that have been successfully adapted for use in this organism. One notable exception is the lack of a negative selection system that can be employed for the easy isolation of markerless in-frame deletions. In this study, we report the development of a galK/galactose-based negative selection system in S. mutans for this purpose. This system consists of a recipient strain (IFD140) that contains a deletion in the galKTE operon and a suicide vector (pIFD-Sm) that carries the S. mutans galK open reading frame fused to the constitutive lactate dehydrogenase (ldh) promoter. Using this system we created a markerless in-frame deletion in the beta-galactosidase (lacG) gene within the S. mutans lactose operon. After vector integration, plasmid excision after counterselection appeared to have occurred in 100% of the galactose-resistant colonies and resulted in in-frame deletions in 50% of the screened isolates. Based on the ratio of galactose-resistant cells to total cells, we determined that plasmid excision occurred at a frequency of approximately 1/3000 cells. Furthermore, the simplicity of this system should make it adaptable for use in numerous other gram-positive and gram-negative organisms.