Identification of novel catalytic features of endo-β-1,4-glucanase produced by mulberry longicorn beetle Apriona germari

Mulberry longicorn beetle, Apriona germari, has been reported to produce two endo-β-1,4-glucanases or AgEGases (accession Nos. Q6SS52 and Q5XQD1). AgEGase sequence contains catalytic motif (amino acid residues 37~48), which is the characteristic of family Glycohydrolase 45 and is identified as the substrate binding site. The application of bioinformatics ap-proaches includes sequence analysis, structural modeling and inhibitor docking to relate the structure and function of AgEGases. We have dissected the sequence and structure of AgEGase catalytic motif and compared it with crystal structure of Humicola insolens endoglucanases V. The results show an involvement of sulfur containing amino acid residues in the active site of the enzyme. Cys residues and position of disulfide bonds are highly conserved between the two structures of endoglucanases of A. germari. Surface calculation of AgEGase structure in the absence of Cys residues reveals greater accessibility of the catalytic site to the substrate involving Asp42, a highly conserved residue. For the inhibition study, tannin-based structure was docked into the catalytic site of AgEGase using ArgusLab 4.0 and it resulted in a stable complex formation. It is suggested that the inhibition could occur through formation of a stable transition state analog-enzyme complex with the tannin-based inhibitor, as observed with other insect cellulases in our laboratory.     

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

This study describes the development and testing of a magnetic microfluidic chip (MMC) for trapping and isolating cells tagged with superparamagnetic beads (SPBs) in a microfluidic environment for selective treatment and analysis. The trapping and isolation are done in two separate steps; first, the trapping of the tagged cells in a main channel is achieved by soft ferromagnetic disks and second, the transportation of the cells into side chambers for isolation is executed by tapered conductive paths made of Gold (Au). Numerical simulations were performed to analyze the magnetic flux and force distributions of the disks and conducting paths, for trapping and transporting SPBs. The MMC was fabricated using standard microfabrication processes. Experiments were performed with E. coli (K12 strand) tagged with 2.8 μm SPBs. The results showed that E. coli can be separated from a sample solution by trapping them at the disk sites, and then isolated into chambers by transporting them along the tapered conducting paths. Once the E. coli was trapped inside the side chambers, two selective treatments were performed. In one chamber, a solution with minimal nutrition content was added and, in another chamber, a solution with essential nutrition was added. The results showed that the growth of bacteria cultured in the second chamber containing nutrient was significantly higher, demonstrating that the E. coli was not affected by the magnetically driven transportation and the feasibility of performing different treatments on selectively isolated cells on a single microfluidic platform.     

Internet in Yemen: Problems and Prospects (A Case Study)

The Internet has caught the public in its expanding web. It is beginning to reshape other media and is now making its way into countries all over the world including developing countries. Yemen, as a developing country, introduced Internet services in September 1996. The present study attempts to evaluate Internet services in Yemen from inception up to the end of 1998. The study also hopes to find, among other things, how well and how widely the Internet is used in Yemen and to what extent Yemen can benefit from it, and how Yemen participates in the information highway. A questionnaire was used as a tool for collecting data. The homepages hosted at the Tele-Yemen (ISP) Server were scanned and certain criteria were used for their evaluation. The study was able to pinpoint the problems faced by Yemeni users of the Internet, the constraints confronting its diffusion in Yemen and the profits gained by subscribers. The study came up with several suggestions and recommendations that the two authors hope will provide a basis for assessing the prospects for the future of the Internet in Yemen.     

Understanding Information-Seeking Behavior for Conducting Tasks: An Exploratory Study

ABSTRACT

The purpose of this study is to investigate the information-seeking behaviors of police officers who work in police stations in the context of conducting tasks. In this study, Leckie et al.'s model of the information-seeking behavior of professionals is tested. The findings indicated that police officers initially consulted their personal knowledge and experience. However, contrary to the expectation, they rarely consulted informants. In addition to this, police officers rarely consulted printed journals, libraries, books, and conferences as information sources. Surprisingly, there were no significant differences in the information sources used by police officers based on their educational level. While bivariate relationships show significant difference for age, service years in police stations, and service years in policing, the same variables do not hold as significant when introduced into multiple regressions. Possible implications of the study were discussed in the conclusion section.     

Content and method

Educational Sociology: A Subject Index of Doctoral Dissertations Completed at American Universities, 1941–1963. Francesco Cordasco and Leonard Covello, compilers. (New York: Scarcecrow Press, 1965. Pp. 226. $5.00.)

The Prospective Teacher's Knowledge of Library Fundamentals. Ralph Perkins. (New York: Scarcecrow Press, 1965. Pp. 202. $4.50.)

Adolescents and the Schools. James S. Coleman. (New York: Basic Books, 1965. Pp. 121. $4.50.)

The Emergent in Curriculum. Gail M. Inlow. (New York: John Wiley and Sons, Inc., 1966. Pp. 353. $6.95.)

Studying History: How and Why. Robert V. Daniels. (New York: Prentice‐Hall, 1966. Pp. 105. $1.50. Paperback)

Physical Education: A Problem‐Solving Approach to Health and Fitness. Perry B. Johnson and others. (New York: Holt, Rinehart and Winston, 1966. Pp. 486. $6.95.)

Teaching Contemporary Mathematics in the Elementary School. Charles F. Howard and Enoch Dumas. (New York: Harper and Row, 1966. Pp. 309. $7.50.)

Education in Metropolitan Areas. Robert J. Havighurst. (Boston: Allyn and Bacon, 1966. Pp. 260. $3.50 Paperback)

The Adolescent Experience. Elizabeth Douvan and Joseph Adelson. (New York: John Wiley and Sons, 1966. Pp. 471. $7.95.)     

Where Arab social science and humanities scholars choose to publish: Falling in the predatory journals trap

The purpose of this paper is to report the findings of a study of publishing behaviour among a group of Arab scholars in social science and humanities disciplines. The paper also investigated the number of Arab scholars who are publishing in predatory journals and the reasons that drive them to select these journals to share their scholarly findings. The study adopted a mixed methods approach. Eighteen journals that were categorized as predatory journals were scanned to find the number of Arab scholars who published in them. Then, a questionnaire was sent to Egyptian and Saudi scholars as they were found to be the top Arab contributors in these journals. The questionnaire was followed by semi‐structured interviews to gain an in‐depth understanding of the publishing behaviour. The data showed that many Arab scholars prefer publishing in predatory journals as these journals are easier and faster. The results also indicate that there is a need to raise the awareness of the harm that predatory journals can cause to the scholars and how they can avoid these journals. This study was conducted with social science and humanities scholars in Egypt and Saudi Arabia. The publishing behaviour may differ in other scholarly disciplines and other Arabic countries.     

Do Black Lives Matter?

This study employs content analysis to examine how the New York Times and St. Louis Post-Dispatch framed “Black Lives Matter” protests in the aftermath of the shooting of unarmed black teenager Michael Brown. The researchers examine all New York Times and St. Louis Post-Dispatch articles dealing centrally with the Michel Brown protests during three separate time periods corresponding to heavy protest activity. The coding scheme measured dominant frame direction, article length, sourcing, and mention of protester crimes. Contrary to expectations, the papers provided overwhelmingly sympathetic coverage of “Black Lives Matter” protests. In describing the protests, both newspapers were much more likely to employ a “positive” frame suggesting peacefulness and order than a “negative” frame suggesting lawlessness and deviance. Neither newspaper over-emphasized protester-perpetrated crimes, with both papers making relatively infrequent mention of looting, arson, assault, and gunfire, respectively. Importantly, both newspapers directly quoted protesters much more often than they quoted police officers and other government officials.