Operator binding by lambda repressor heterodimers with one or two N-terminal arms.

The first 6 amino acids (NH2-Ser1-Thr2-Lys3-Lys4-Lys5-Pro6) of bacteriophage lambda cI repressor form a flexible arm that wraps around the operator DNA. Homodimeric lambda repressor has two arms. To determine whether both arms are necessary or only one arm is sufficient for operator binding, we constructed heterodimeric repressors with two, one, or no arms by fusing the DNA binding domain of lambda repressor to leucine zippers from Fos and Jun. Although only one arm is visible in the cocrystal structure of the N-domain-operator complex, our results indicate that both arms are required for optimal operator binding and normal site discrimination.

Binding of purified multiple antibiotic-resistance repressor protein (MarR) to mar operator sequences.

Elevated expression of the marORAB multiple antibiotic-resistance operon enhances the resistance of Escherichia coli to various medically significant antibiotics. Transcription of the operon is repressed in vivo by the marR-encoded protein, MarR, and derepressed by salicylate and certain antibiotics. The possibility that repression results from MarR interacting with the marO operator-promoter region was studied in vitro using purified MarR and a DNA fragment containing marO. MarR formed at least two complexes with marO DNA, bound > 30-fold more tightly to it than to salmon sperm DNA, and protected two separate 21-bp sites within marO from digestion by DNase I. Site I abuts the downstream side of the putative -35 transcription-start signal and includes 4 bp of the -10 signal. Site II begins 13 bp downstream of site I, ending immediately before the first base pair of marR. Site II, approximately 80% homologous to site I, is not required for repression since a site II-deleted mutant (marO133) was repressed in trans by wild-type MarR. The absence of site II did not prevent MarR from complexing with the site I of marO133. Salicylate bound to MarR (Kd approximately 0.5 mM) and weakened the interaction of MarR with sites I and II. Thus, repression of the mar operon, which curbs the antibiotic resistance of E. coli, correlates with the formation of MarR-site I complexes. Salicylate appears to induce the mar operon by binding to MarR and inhibiting complex formation, whereas tetracycline and chloramphenicol, which neither bind MarR nor inhibit complex formation, must induce by an indirect mechanism.

The First Child In A Chinese Family Who Could Read Prior To Entry Into Elementary School: A Qualitative Intrinsic Case Study

ABSTRACT This study is an account of the literacy-related human environment a Chinese girl experienced as the first person in the history of her family who was able to read prior to entry into elementary school. Temporally speaking, the study spanned more than a decade from the initial, tentative research question to the formal, primary research question. Spatially speaking, it crossed three cultures: the Chinese, Korean, and American cultures. The study was inspired by the Zero Project in China, known as the "Project of Quality Education and Implementation for Children Aged Zero (fetus) to Six." The significance of the content issue in a child's literacy curriculum was explored in an interdisciplinary way. Case study served as a holistic research approach and provided the researcher with free temporal and spatial distance to pursue the indefinably multi-dimensional intricacies of a child's early literacy acquisition among generations in the family. Interpretation of the case was based on the relevant concepts within the scope of the researcher's knowledge of Chinese culture. Major findings revealed that the child's literacy acquisition was inseparably related to her parents' background as well as their awareness of and attitudes towards literacy, and that the foundation of all this was the harmony of the family. Through the lens of generational attitudes towards literacy and especially the lens of the researcher's multicultural life experiences, this study contributes to the field of curriculum studies in general and early literacy curriculum in particular by stimulating people to reconsider what to read to children, besides how to read to them. It calls attention once again to the classic curriculum question, "What knowledge is of most worth?" as well as what is the most essential spiritual food human beings need besides physical needs. This study suggests that Chinese philosophy should be included in a child's early literacy curriculum in China and calls for dialogues on the content issue of curriculum to gain a deeper understanding of human nature so that humans might co-live peacefully with all beings in the universe.

Mathematics Game e-Library for Elementary School, study case: Mexico

One of the most relevant subjects for the intellectual formation of elementary school students is Mathematics where its importance goes back to ancient civilizations and which its importance is underestimated nowadays. This phenomenon occurs in Mexico, where 63.1% of the total population of elementary school students between the third and sixth grade have insufficient/elemental level of mathematics knowledge. This has resulted in the need to use a new mechanism to complement student’s classroom learning. With the rapid growth of wireless and mobile technologies, the mobile learning has been gradually considered as a novel and effective form of learning due to it inherits all the advantages of e-learning as well as breaks the limitations of learning time and space occurring in the traditional classroom teaching. This project proposes the use of a Mathematics Game e-Library integrated by a set of games for mobile devices and a distribution/management tool. The games are developed for running on mobile devices and for cover the six competencies related with the mathematics learning approach established in Mexico. The distribution/management tool allows students to reach contents according to their needs; this is achieved through a core engine that infers, from an initial profile, the games that cover the user’s knowledge gaps.

Considering Efficacy of an Outdoor Environmental Education Program: Facilitating Elementary Students’ Environmental Knowledge, Attitudes, and Behaviours

Various sources have sought to consider the educational interventions that foster changes in perception of and attitudes toward nature, with the ultimate intent of understanding how education can be used to encourage environmentally responsible behaviours. With these in mind, the current study identified an outdoor environmental education program incorporating these empirically supported interventions, and assessed its ability to influence environmental knowledge, attitudes, and behaviours. Specifically, this study considered the following research questions: 1) To what degree can participation in this outdoor education program foster environmental knowledge and encourage pro-environmental attitudes and self-reported pro-environmental behaviours? 2) How is this effect different among students of different genders, and those who have different prior experiences in nature? Two motivational frameworks guided inquiry in the current study: the Value-Belief-Norm Model of Environmentalism (VBN) and the Theory of Planned Behaviour (TPB). The study employed a quantitative survey methodology, combining contemporary data measuring knowledge, attitudes, and behaviours with archived data collected by program staff, reflecting frequency of environmentally responsible behaviour. Further, a single qualitative item was included for which students provided “the first three words that [came] to mind when [they] think of the word nature.” Terms provided before and after the program were compared for differences in theme to detect subtle or underlying changes. Quantitative results indicated no significant change in student knowledge or attitudes through the outdoor environmental education program. However, a significant change in self-reported behaviour was identified from both the contemporary and archived data. This agreement in positive findings across the two data sets, collected using different measures and different participants, lends evidence of the program’s ability to encourage self-reported pro-environmental behaviour. Further, qualitative results showed some change in students’ perceptions of nature through the program, providing direction for future research. These findings suggest that this particular outdoor education program was successful in encouraging students’ self-reported environmentally responsible behaviour. This change was achieved without significant change in knowledge or environmental attitudes, suggesting that external factors not measured in this study might have played a role in affecting behaviour.

Sound and music: an elementary treatise on the physical constitution of musical sounds and harmony, including the chief acoustical discoveries of Professor Helmholtz.

Mode of access: Internet.

Diet in dyspepsia and other diseases of the stomach and bowels : an elementary treatise on their dietetic and hygienic management.

Mode of access: Internet.

Elementary hydrostatics, with chapters on the motion of fluids and on sound.

Mode of access: Internet.