Foraging and pollination behaviour of Xylocopa calens Lepeletier (Hymenoptera: Apidae) on Phaseolus coccineus L. (Fabaceae) flowers at Yaounde (Cameroon)

Joseph Blaise PANDO,Fernand-Nestor Tchuenguem FOHOUO,Joseph Lebel Tamesse 한국곤충학회 2011 Entomological Research Vol.41 No.5

To evaluate impact of carpenter bee, Xylocopa calens, on pod and seed set of Phaseolus coccineus, its foraging and pollinating activities were studied in Yaounde, for two seasons (May–July 2008 and April–June 2009). Observations were made on 40 inflorescences per treatment. The treatments included unlimited floral access by all visitors, bagged flowers to deny all visits, and limited visits by X. calens only. In addition, all flower visitors were recorded. The carpenter bee's seasonal rhythm of activity, its foraging behavior on flowers, its pollination efficiency, the fructification rate and the number of seeds per pod were recorded. Individuals from 16 species of insects were recorded visiting flowers of P. coccineus in the 2 years. Xylocopa calens was the most frequent, followed by Chalicodoma cincta cincta and Apis mellifera. Apart from bees, wasps were also recorded as likely predators. Xylocopa calens mainly foraged for nectar resources. The mean foraging speed was 9.62 flowers/min. Flowers visited by X. calens had higher fruiting rate compared with others, while those bagged had the lowest. In addition, seed formation was higher in X. calens-visited flowers compared with all others. The results show that this crop experiences pollination deficit even under normal circumstances, considering that flowers visited by X. calens had higher yields compared with those under unlimited access by all visitors. The fruiting rate, the number of seeds/pod and the percentage of normal seeds of unprotected inflorescences were significantly higher than those of inflorescences protected from insects. X. calens foraging resulted in a significant increment of the fruiting rate by 25.80%, as well as the number of seeds/pod by 14.97% and the percentage of normal seeds by 27.75% in 2008 and 18.39% in 2009. Conservation of X. calens nests close to P. coccineus fields could be recommended to improve pod and seed production in the region.

From Signtometrics to Scientometrics: A Cautionary Tale of Our Times

Cronin, Blaise Korea Institute of Science and Technology Informat 2013 Journal of Information Science Theory and Practice Vol.1 No.4

It is but a short journey from citation indexing to citation analysis and thence to evaluative bibliometrics. This paper outlines the path and describes how the time-honored practice of affixing bibliographic references to scholarly articles has paved the way for a culture of accounting to establish itself in contemporary academia.

矛盾 <SUB>모순</SUB>

블라즈 파스칼(Blaise Pascla) 문예운동사 2017 수필시대 Vol.12 No.11·12

지치(Lithospermum erythrorhizon) 추출물의 멜라닌 생합성 억제효과

이황희(Hwanghee Blaise Lee),배석(Suk Bai),진종언(Jong-Eon Chin) 한국식품영양과학회 2005 한국식품영양과학회지 Vol.34 No.9

유전자 발현 조절 수준에서 멜라닌 색소 생합성 억제물질을 탐색하고자 지치 뿌리로부터 유용성 물질을 추출ㆍ분획하여 tyrosinase 프로모터를 지닌 B16 mouse melanoma cell에 처리한 결과 그 메탄올 추출물은 10 ㎍/mL의 농도에서 약 33% 이상의 tyrosinase 프로모터 활성 억제효과를 나타내었으며, 세포 활성능이 100 ㎍/mL의 농도에서 약 108%로 매우 안전하였다. 그리고 methylene chloride, ethyl acetate, butyl alcohol, 물 등의 용매 분획물들도 농도에 따라 차이는 있었지만 100 ㎍/mL 또는 500 ㎍/mL의 고농도에서 tyrosinase 프로모터의 활성을 억제하였다. 또한, 지치 메탄올 추출물의 농도를 달리하여 3일 동안 처리하였을 때 멜라닌 색소의 생성능은 10 ㎍/mL와 100 ㎍/mL의 농도에서 대조군 세포에 비해 각각 약 11%와 24%로 크게 감소하는 결과를 보여주었다. To estimate the inhibitory effect of Lithospermum erythrorhizon root extract on melanin biosynthesis, we tested its inhibitory effects on tyrosinase promoter in B16 mouse melanoma cells. Lithospermum erythrorhizon root extract had inhibitory effect above 33% on tyrosinase promoter at 10 ㎍/mL and exhibited no cytotoxicity under 100 ㎍/mL. Also, melanin biosynthesis decreased approximately 11% and 24% at 10 ㎍/mL and 100 ㎍/ mL, respectively. Therefore, Lithospermum erythrorhizon root extract would be considered very effective regulator of tyrosinase promoter and melanin biosynthesis.

Mechanical and Dynamic Mechanical Studies on Epoxy-Cobaltous Sulfate Polymer Hybrids

Shruti S. Devangamath,Blaise Lobo,Saraswati P. Masti,Shivayogi Narasagoudr 한국섬유공학회 2018 Fibers and polymers Vol.19 No.7

Cobaltous sulfate heptahydrate (CoSO4·7H2O) was incorporated as filler into diglycidyl ether of bisphenol A (DGEBA) based epoxy resin system, to prepare organic-inorganic polymer hybrid materials. Mechanical tensile studies and dynamic mechanical analysis (DMA) were carried out in order to study the static and dynamic mechanical properties of the prepared hybrid films. Mechanical tensile studies were carried out at room temperature, at a test speed of 30 mm/min. Highest tensile strength of 24.74±2.42 MPa was achieved for 4.44 wt% filler level (FL), along with an increase in the value of Young’s modulus. Storage modulus (E'), loss modulus (E''), damping factor (tan δ) were obtained by DMA studies. Glass transition temperature (Tg) was obtained for pure epoxy and filled epoxy, for various FLs varying from 0.28 wt% to 5.00 wt%. Pure epoxy showed highest Tg value compared to filled epoxy hybrids. Highest storage modulus of 9.5 GPa was obtained for 2.22 wt% FL, which also showed highest loss modulus peak. Parameters like effectiveness coefficient (C) and crosslink density were calculated from the storage modulus data. Loss modulus and tan δ curves were analyzed to study the energy dissipation properties of prepared hybrid films. Activation energy (Ea) value for glass transition was obtained from damping factor (tan δ), which showed highest Ea value of 630.5 kJmol-1, for 4.44 wt% FL. DMA studies for various FLs were carried out at different test frequencies in order to study the changes in dynamic mechanical properties of the prepared hybrid materials with respect to frequency.

Accumulation of heavy metals in surface sediments of Lere Lake, Chad

Léopold Nga Ekengele,Apelbo Blaise,정명채 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.2

Thirty surface sediment samples collected from Lere Lake were analyzed for As, Co, Cr, Cd, Cu, Ni, Pb, Sb, Sn, Zn, Fe, pH, Electrical Conductivity (EC) and Organic Matter (OM) in order to assess the current pollution status in sediments of the study area. Sediment pollution assessment was carried out using Enrichment Factor (EF) and Geo-accumulation index (Igeo). The potential ecotoxic effects were evaluated based on sediment quality guidelines. The calculated enrichment factor showed that the sediment was mostly enriched with Sb, Cd, Cu, and Cr. The results of the geo-accumulation index indicated that sediments were unpolluted with Sn, Co, Pb; moderately polluted with As, Cr, Cd, Cu, Ni, Zn, and strongly polluted with Sb. This pollution was attributed to anthropogenic activities caused by the sloping side of Lere Lake including consisting of mainly waste disposal, chemicals used in agriculture, and gold exploitation. Sites that exceeded TEL for Cr and Ni and PEL for Cr are ranked at the highest priority level in terms of potential ecological risk.

Effect of Enzymatic Methylation of Proteins on Their Isoelectric Points

Park, Kwang-Sook,Frost, Blaise F.,Lee, Hyang-Woo,Kim, Sang-Duk,Paik, Woon-Ki The Pharmaceutical Society of Korea 1989 Archives of Pharmacal Research Vol.12 No.2

Enzymatic methylation of arginine and lysine residues of several cytochrome c and lysine residue of calmodulin always resulted in lowering of their respective isoelectric points (pI). Employing cytochromes c derived from various sources, we examined a possible relationship between the degree of amino acid sequence degeneracy and the magnitude of change in the pI values by enzymatic methylation, and found that there was no correlation between these two parameters. By constructing space-filling models of oligopeptide fragments adjacent to the potential methylation sites, we have noted that not all the methylatable residues are able to form hydrogen bonds prior to the methylation. Two preparations of yeast apocytochrome c, one chemically prepared by removing heme from holocytochrome c and the other by translating yeast iso-1-cytochrome c mRNA in vitro, exhibited slightly higher Stokes radii than the homologous holocytochrome c, indicating relatively 'relaxed or open' conformation of the protein. However, when the in vitro synthesized methylated apocytochrome c was compared with the unmethylated counter-part, the Stokes radius of the latter was found to be larger.

Cytochrome C methylation: Current Knowledge of its Biological Significance

Park, Kwang-Sook,Frost, Blaise F.,Lee, Hyang-Woo,Kim, Sang-Duk,Paik, Woon-Ki The Pharmaceutical Society of Korea 1988 Archives of Pharmacal Research Vol.11 No.1

The yeast cytochrome c gene has been recloned, and the resulting cytochrome c mRNA has been translated in rabbit reticulocyte lysate translation system. The newly synthesized apocytochrome c could be methylated by exogenously added cytochrome c-lysine N-methyltransferase. Enzymatic methylation of in vitro synthesized apocytochrome c was found to facilitate specifically its import into mitochondria of yeast, but not of rat liver.

Study of Chitosan on Fibroblast Growth Factor 2 (bFGF) from the Renal Proximal Tubular Cells

( Hyun Joong Yoon ),( Young Ho Kim ),( Hwanghee Blaise Lee ),( Jun Heung Lee ),( Haeng Soon Park ) 한국키틴키토산학회 2004 한국키틴키토산학회지 Vol.9 No.3

Antidiabetic effect of propolis: reduction of expression of glucose-6-phosphatase through inhibition of Y279 and Y216 autophosphorylation of GSK-3&agr;/&bgr; in HepG2 cells

Kang, Li-Jung,Lee, Hwanghee Blaise,Bae, Hyeun-Jong,Lee, Seong-Gene John Wiley Sons, Ltd. 2010 Phytotherapy research Vol.24 No.10

<P>Propolis is a sticky, resinous material that honey bees collect from various plants, and mix with wax and other secretions. The aim of this study was to evaluate the antidiabetic effect of propolis through an analysis of the expression and enzyme activity of glucose-6-phosphatase (G6Pase) and to elucidate the mechanism by which propolis inhibits G6Pase gene expression. When HepG2 cells were incubated in high glucose media (25 mm), G6Pase expression was induced. Propolis significantly reduced the expression and enzyme activity of G6Pase; however, the hypoglycemic effect was not abolished by the phosphoinositide 3-kinase inhibitor, LY294002, and by the mitogen-activated protein kinase (MAPK) inhibitor, U0126. Propolis inhibited the activity of GSK3&agr; and &bgr; via the inhibition of serine and tyrosine phosphorylation, specifically, Y279 for GSK3&agr; and Y216 for GSK3&bgr;. The phosphorylations of Y279 and Y216 occur through autophosphorylation by GSK3&agr;/&bgr; and are involved in their own activity. Although propolis showed antioxidant activity, antidiabetic effect of propolis was not influenced by hydrogen peroxide and N-acetylcysteine. These results suggest that propolis inhibits the expression of G6Pase by inhibiting the autophosphorylation of Y279 and Y216 of GSK3&agr; and &bgr;, respectively, which are involved in the activation of GSK3. These findings suggest that propolis may be a potential antidiabetic agent for the treatment of insulin-insensitive diabetes. Copyright © 2010 John Wiley & Sons, Ltd.</P>