Dengue Outbreak in Mombasa City,Kenya, 2013–2014: Entomologic Investigations

Dengue outbreaks were first reported in East Africa in the late 1970s to early 1980s including the 1982 outbreak on the Kenyan coast. In 2011, dengue outbreaks occurred in Mandera in northern Kenya and subsequently in Mombasa city along the Kenyan coast in 2013–2014. Following laboratory confirmation of dengue fever cases, an entomologic investigation was conducted to establish the mosquito species, and densities, causing the outbreak. Affected parts of the city were identified with the help of public health officials. Adult Ae. aegypti mosquitoes were collected using various tools, processed and screened for dengue virus (DENV) by cell culture and RT-PCR. All containers in every accessible house and compound within affected suburbs were inspected for immatures. A total of 2,065 Ae. aegypti adults were collected and 192 houses and 1,676 containers inspected. An overall house index of 22%, container index, 31.0% (indoor = 19; outdoor = 43) and Breteau index, 270.1, were observed, suggesting that the risk of dengue transmission was high. Overall, jerry cans were the most productive containers (18%), followed by drums (17%), buckets (16%), tires (14%) and tanks (10%). However, each site had specific most-productive container-types such as tanks (17%) in Kizingo; Drums in Nyali (30%) and Changamwe (33%), plastic basins (35%) in Nyali-B and plastic buckets (81%) in Ganjoni. We recommend that for effective control of the dengue vector in Mombasa city, all container types would be targeted. Measures would include proper covering of water storage containers and eliminating discarded containers outdoors through a public participatory environmental clean-up exercise. Providing reliable piped water to all households would minimize the need for water storage and reduce aquatic habitats. Isolation of DENV from male Ae. aegypti mosquitoes is a first observation in Kenya and provides further evidence that transovarial transmission may have a role in DENV circulation and/or maintenance in the environment.     

An extract of Ulmus macrocarpa improves cellular immunity in immuno-suppressed models

An extract of Ulmus macrocarpa Hance, commonly known as the large-fruited elm, has been prescribed as a traditional medicine. In this study, we aimed to investigate the cellular immune effects of U. macrocarpa stem cortex extracts on cyclophosphamide (CY)-treated splenocytes and mice. A methanol extract showed an improved survival rate of splenocytes after 72?h. The extract was successively partitioned with dichloromethane, ethyl acetate, n-butanol, and water; and the fractions so obtained were also examined for their proliferative activity. Among them, the water fraction of U. macrocarpa showed the highest proliferation of splenocytes and was used throughout the present study. We tested the survival rate of splenocytes through dose-dependent treatment of CY and the suppression of the survival effect by CY was recovered by treatment with the water extract of U. macrocarpa. To determine the mechanism involved, we examined the expression of B-cell lymphoma-extra large (Bcl-xL) anti-apoptotic protein. CY decreased Bcl-xL protein levels in resting splenocyte cultures, whereas splenocytes were exposed to water extracts of U. macrocarpa in the presence of CY; however, elevations in Bcl-xL were observed at 96?h. Mice splenocytes treated with water extract of U. macrocarpa for cellular immunity showed an increase in the activity of the mixed lymphocyte reaction (MLR), cytotoxic T lymphocytes (CTLs), and natural killer (NK) cells. In addition, mice receiving a water extract of U. macrocarpa recovered the CTL, NK, and MLR activities suppressed by CY administration. Consequently, U. macrocarpa improves the cell-mediated immune response and provides an insight on cell-based tonic materials.     

High-level SUMO-mediated fusion expression of ABP-dHC-cecropin A from multiple joined genes in Escherichia coli

The antimicrobial peptide ABP-dHC-cecropin A is a small cationic peptide with potent activity against a wide range of bacterial species. Evidence of antifungal activity has also been suggested; however, evaluation of this peptide has been limited due to the low expression of cecropin proteins in Escherichia coli. To improve the expression level of ABP-dHC-cecropin A in E. coli, tandem repeats of the ABP-dHC-cecropin A gene were constructed and expressed as fusion proteins (SUMO-nABP-dHC-cecropin, n = 1, 2, 3, 4) via pSUMO-nABP-dHC-cecropin A vectors (n = 1, 2, 3, 4). Comparison of the expression levels of soluble SUMO-nABP-dHC-cecropin A fusion proteins (n = 1, 2, 3, 4) suggested that BL21 (DE3)/pSUMO-3ABP-dHC-cecropin A is an ideal recombinant strain for ABP-dHC-cecropin A production. Under the selected conditions of cultivation and isopropylthiogalactoside (IPTG) induction, the expression level of ABP-dHC-cecropin A was as high as 65 mg/L, with ∼21.3% of the fusion protein in soluble form. By large-scale fermentation, protein production reached nearly 300 mg/L, which is the highest yield of ABP-dHC-cecropin A reported to date. In antibacterial experiments, the efficacy was approximately the same as that of synthetic ABP-dHC-cecropin A. This method provides a novel and effective means of producing large amounts of ABP-dHC-cecropin A.     

Effect of exogenous abscisic acid on cold acclimation in two Magnolia species

In northern China, freezing injury is observed frequently in the rare species Magnolia wufengensis but not in the more common species Magnolia denudata. To investigate the role of the phytohormone abscisic acid (ABA) on frost tolerance in these two species, exogenous ABA was applied to the seedlings and then physiological and biochemical responses were measured during cold acclimation. Shoot growth cessation was stimulated by ABA in M. wufengensis but not in M. denudata. Abscisic acid inhibited shoot growth in M. wufengensis but not in M. denudata. Treatment with ABA stimulated leaf senescence in both species, and this effect was greater in M. denudata. For both species, ABA-treated plants exhibited bud dormancy sooner and had an increased tolerance to freezing, decreased water content and increased accumulation of proline, glucose, and fructose in shoots. These effects were generally greater for M. denudata. Freezing tolerance was significantly correlated with content of water, proline, glucose, and fructose for both species, but freezing tolerance was significantly correlated with raffinose content only in M. wufengensis. We conclude that exogenous ABA could increase cold acclimation and improve cold hardiness of both Magnolia species, although M. denudata was more responsive to ABA than M. wufengensis, which might result from a greater dehydration and accumulation of proline and certain soluble sugars.     

ATP‐dependent DNA binding,unwinding, and resection by the Mre11/Rad50 complex

ATP‐dependent DNA end recognition and nucleolytic processing are central functions of the Mre11/Rad50 (MR) complex in DNA double‐strand break repair. However, it is still unclear how ATP binding and hydrolysis primes the MR function and regulates repair pathway choice in cells. Here, Methanococcus jannaschii MR‐ATPγS‐DNA structure reveals that the partly deformed DNA runs symmetrically across central groove between two ATPγS‐bound Rad50 nucleotide‐binding domains. Duplex DNA cannot access the Mre11 active site in the ATP‐free full‐length MR complex. ATP hydrolysis drives rotation of the nucleotide‐binding domain and induces the DNA melting so that the substrate DNA can access Mre11. Our findings suggest that the ATP hydrolysis‐driven conformational changes in both DNA and the MR complex coordinate the melting and endonuclease activity.     

Association of three single nucleotide polymorphisms at the SIX1-SIX6 locus with primary open angle glaucoma in the Chinese population

This study investigated the genetic association of three single nucleotide polymorphisms(SNPs; rs10483727, rs33912345, and rs146737847) at the SIX1-SIX6 locus with primary open angle glaucoma(POAG) in the Chinese population. A total of 866 subjects with POAG(685 high-tension glaucoma(HTG) and 181 normal-tension glaucoma(NTG)) and 266 control individuals were included. Significant genetic association was identified for rs10483727 in HTG(P=0.02; odds ratio(OR)=1.31), NTG(P=7.41×10~(-6); OR=2.71), and POAG(i.e., HTG and NTG combined; P=0.001; OR=1.44). rs33912345 was also significantly associated with HTG(P=0.008; OR=1.36), NTG(P=2.72×10~(-6); OR=2.27), and POAG(P=3.84×10~(-4); OR=1.49). The rare SIX6 mutation, rs146737847, was not found in the subjects enrolled in this study. Stratification by patient age identified that both rs10483727 and rs33912345 were significantly associated with NTG in patients aged above 40 years(P=2.08×10~(-5); OR=2.28), whereas in patients aged between 20–40 years, rs33912345 was significantly associated with NTG(P=0.017; OR=2.06). In HTG, the genetic associations for both rs10483727 and rs33912345 were significant in patients aged between 20–40 years(P=0.006; OR=1.56) but not in those aged above 40 years(P=0.118, OR=1.21 and P=0.042, OR=1.29, respectively). This study replicated the association of POAG with two SNPs at the SIX1-SIX6 locus and demonstrated that SNPs, rs10483727 and rs33912345, are significantly associated with POAG, especially with NTG in patients aged above 40 years.     

P2Y12 antagonist attenuates eosinophilic inflammation and airway hyperresponsiveness in a mouse model of asthma

Leukotriene E4 (LTE4) that plays a key role in airway inflammation is expressed on platelets and eosinophils. We investigated whether blocking of the P2Y12 receptor can suppress eosinophilic inflammation in a mouse model of asthma because platelets and eosinophils share this receptor to be activated. BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA), followed by OVA nebulization. On each challenge day, clopidogrel, a P2Y12 antagonist was administered 30 min. before each challenge. Forty‐eight hours after the last OVA challenge, mice were assessed for airway hyperresponsiveness (AHR), cell composition and cytokine levels, including chemokine ligand 5 (CCL5), in bronchoalveolar lavage (BAL) fluid. EOL cells were treated with LTE4, with or without clopidogrel treatment, and intracellular and extracellular eosinophil cationic protein (ECP) expressions were measured to find the inhibiting function of P2Y12 antagonist on eosinophilic activation. The levels of P2Y12 expression were increased markedly in the lung homogenates of OVA‐sensitized and ‐challenged mice after platelet depletion. Administration of clopidogrel decreased AHR and the number of airway inflammatory cells, including eosinophils, in BAL fluid following OVA challenge. These results were associated with decreased levels of Th2 cytokines and CCL5. Histological examination showed that inflammatory cells as well as mucus‐containing goblet cells were reduced in clopidogrel‐administered mice compared to vehicle‐treated mice. Clopidogrel inhibited extracellular ECP secretion after LTE4 stimulation in EOL‐1 cells. Clopidogrel could prevent development of AHR and airway inflammation in a mouse model of asthma. P2Y12 can be a novel therapeutic target to the suppression of eosinophils in asthma.