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Blue and red lights differently regulate leaf photosynthesis. Previous studies indicated that plants under blue light generally exhibit better photosynthetic characteristics than those under red light. However, the regulation mechanism of related photosynthesis characteristics remains largely unclear. Here, four light qualities treatments (300 μmol m-2 s-1) including white fluorescent light (FL), blue monochromatic light (B, 440 nm), red monochromatic light (R, 660 nm), and a combination of red and blue light (RB, R:B=8:1) were carried out to investigate their effects on the activity of photosystem II (PSII) and photosystem I (PSI), and photosynthetic electron transport capacity in the leaves of cucumber (Cucumis sativus L.) seedlings. The results showed that compared to the FL treatment, the R treatment significantly limited electron transport rate in PSII (ETR II) and in PSI (ETR I) by 79.4% and 66.3%, respectively, increased non-light induced non-photochemical quenching in PSII (Φ NO) and limitation of donor side in PSI (Φ ND) and reduced most JIP-test parameters, suggesting that the R treatment induced suboptimal activity of photosystems and inhibited electron transport from PSII donor side up to PSI. However, these suppressions were effectively alleviated by blue light addition (RB). Compared with the R treatment, the RB treatment significantly increased ETR II and ETR I by 176.9 and 127.0%, respectively, promoted photosystems activity and enhanced linear electron transport by elevating electron transport from Q A to PSI. The B treatment plants exhibited normal photosystems activity and photosynthetic electron transport capacity similar to that of the FL treatment. It was concluded that blue light is more essential than red light for normal photosynthesis by mediating photosystems activity and photosynthetic electron transport capacity.

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BackgroundDiarrhea is one of the main causes of morbidity and mortality among children less than 5 years of age worldwide, and its causes vary by region. This study aimed to determine the etiologic spectrum, prevalent characteristics and antimicrobial resistance patterns of common enteropathogenic bacteria from diarrheagenic children in Beijing, the capital of China.MethodsStool samples were collected from 2524 outpatients who were aged 0–5 years in Beijing, China during 2010–2014. Microbiological methods, real-time PCR and antimicrobial susceptibility test were used to identify the bacterial causes and antimicrobial resistance patterns in the isolates.ResultsOf the 2524 patients screened, we identified the causes of 269 cases (10.7 %) as follows: diarrheagenic Escherichia coli (4.6 %), Salmonella (4.3 %), Shigella (1.4 %) and Vibrio parahaemolyticus (0.4 %). Atypical EPEC, Salmonella enteritidis, Shigella sonnei and serotype O3:K6 were the most common serogroups or serotypes of the four etiological bacteria. The prevalence of pathogens was correlated with age, season and clinical symptoms. The highest proportion of all causative bacteria was found in children aged 3–5 years and in summer. The clinical symptoms associated with specific bacterial infection, such as fever; abdominal pain; vomiting; and watery, mucus, and bloody stool, were observed frequently in diarrheal patients. Salmonella showed moderate rates of resistance (40–60 %) to ampicillin, nalidixic acid, streptomycin and sulfisoxazole. Resistance to at least three antimicrobials was found in 50 % of isolates. Of the top three serotypes in Salmonella, high-level antimicrobial resistance to single and multiple antibiotics was more common among Salmonella typhimurium and Salmonella 1, 4, [5], 12:i:- than among S. enteritidis. More than 90 % of Shigella isolates showed more alarming resistance to most antibiotics, with a widened spectrum compared to Salmonella.ConclusionConstant antibiotic surveillance is warranted because the bacteria were highly resistant to various antimicrobials. Our study contributes to the strengthening of the existing surveillance system and provides aid for effective prevention and control strategies for childhood diarrhea.Electronic supplementary materialThe online version of this article (doi:10.1186/s13099-016-0116-2) contains supplementary material, which is available to authorized users.

BackgroundHand, foot and mouth disease (HFMD) is a common illness in young children. It also can be seen in adults occasionally. Enterovirus 71 (EV71), a pathogen that causes not only HFMD but also neurological complications and even death, has caused many HFMD outbreaks in China. However, till now the data about the duration of EV71 shedding is very limited.ResultsA total of 136 throat swabs and fecal samples were collected from 27 children and 3 adults, which includs 7 close contacts, 9 mild cases and 14 severe cases,. The participants were divided into three groups namely, severe case group, mild case group and close contact group. All the samples were assayed with real-time polymerase chain reaction (PCR). Kruskal-Wallis Test was employed to compare the difference in duration of viral RNA shedding among three groups. The results showed that significant difference in duration of EV71 shedding was found among three groups (P < 0.01). The longest duration of EV71 shedding in fecal samples is 54 days and 30 days in throat swabs.ConclusionsHFMD is characterized by extended excretion of EV71. Our results suggest that the duration of EV71 shedding is correlated with the severity of the disease. EV71 shedding through feces can persist more than 54 days. Prolonged virus shedding is a potential risk factor of proliferating HFMD epidemic.

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