Oxidative enzymes activities of mycorrhizal inoculated pepper plant infected with phytophthora infestans

The activities of polyphenol oxidase, peroxidase and catalase were investigated in Glomus etunicatum an arbuscular mycorrhizal inoculated pepper plant infected with Phytophthora infestans. Pepper plant inoculated with pathogen alone, simultaneously inoculated with mycorrhizal and pathogen or dually inoculated with pathogen before mycorrhizal had increased level of the oxidative enzymes activities especially at 4 weeks after planting. Of the three oxidases investigated catalase had the highest level of activities in all the treatments while the level of peroxidase was the lowest. The results showed that pathogen alone, build up the level of the oxidases in the inoculated pepper plant while inoculation of the pepper plant with AM mycorrhizal either simultaneously or dually with pathogen lower the activity of the oxidases indicating a passive protective effect of mycorrhizal.     

Effect of essential oils on postharvest decay and quality factors of tomato in vitro and in vivo conditions

For increasing the shelf life and control of devastating fungal pathogen grey mould (Botrytis cinerea), tomato fruits during storage were applied different concentrations of ammi (Carum copticum) and anise (Pimpinella anisum) essential oils. First, antifungal activities of essential oils were tested on artificial growth media. The growth of grey mould was completely inhibited by ammi and anise essential oils at relatively higher concentrations. In second stage, fruits were infected artificially by grey mould spore and then treated with different concentrations of these essential oils. The results of in vivo conditions showed that ammi and anise essential oils applied at all concentrations were increasing the shelf life and inhibited the grey mould growth on tomato fruits completely in comparison to control. Fruits treated with these essential oils had significantly higher total soluble solids (TSS), ascorbic acid, β-carotene and lycopene content compared to control fruits.     

Plasmodium falciparum RuvB1 is an active DNA helicase and translocates in the 5′–3′ direction

RuvB family of protein contains two similar kinds of proteins i.e. RuvB1 and RuvB2 from yeast to human. These proteins belong to the AAA + class of proteins and are critical components of several multiprotein complexes involved in diverse cellular activities. There are two RuvB proteins annotated in the Plasmodium database but the identification of the third protein recently by our lab has raised the question why Plasmodium falciparum contains three RuvB proteins instead of two. Hence the biochemical characterizations of these proteins have become essential to understand the role of these proteins in the malaria parasite. Recently we have reported the characterization of the recombinant PfRuvB3, which contains ATPase activity but lacks DNA helicase activity. In the present study we report the phylogenetic analysis and detailed biochemical characterization of one of the other RuvB homologue RuvB1 from P. falciparum. PfRuvB1 shows considerable homology with human as well as yeast RuvB1 and contains Walker motif A and Walker motif B. The activity analysis of this protein revealed that PfRuvB1 is an ATPase and this activity increased significantly in the presence of ss-DNA. PfRuvB1 also contains DNA helicase activity and translocates preferentially in 5′ to 3′ direction. In vivo investigation of PfRuvB1 revealed that it is constitutively expressed during all the stages of intraerythrocytic cycle of P. falciparum and localizes mainly to the nucleus. These studies will make important contribution in understanding the role of RuvB protein in P. falciparum.     

Chronotype preferences of college students from varied altitude backgrounds in Ethiopia

ABSTRACT

The purpose of this study was to compare chronotype preferences of college students from high- and low-altitude backgrounds living in a tropical setting of Ethiopia. Chronotype (morningness–eveningness) is a preference for a given time of day for physical or mental activities. The present cross-sectional study employed Horne and Osteberg Morningness-Eveningness Questionnaires to evaluate chronotype preferences. The chronotype preference of 264 male college students from varied altitude backgrounds indicated significant differences (p < 0.001). Our findings confirm our hypothesis, of the prevalence of M-types dominant chronotype among college students at low than high altitude. However, we did not confirm our second hypothesis, since students from high-altitude backgrounds were generally I-type dominant chronotype. Similarly, students’ academic performances from low- compared to high-altitudes backgrounds also indicated significant differences (p < 0.003). Better academic performances were seen in students with I-type chronotype orientations from high altitudes.     

Using an Activity to Simulate the Dangers of Multitasking with Technology while Walking

People are increasingly trying to multitask while walking. Text messaging while walking is a significant area for concern. The number of text messages sent is expected to be more than 8 trillion in 2012. Texting is becoming so commonplace that people use this technology while engaged in other activities. The dangers of multitasking have hit the streets as people are becoming involved in more accidents while walking as they text on mobile phones. This simulation activity measures a student's ability to multitask by texting and walking. The activity simulates walking in the real world and is best suited for middle school students. Additional activities, after completing the simulation, will challenge middle school students to learn more about multitasking globally through scientific inquiry researched on the Internet. The students will use language arts skills to generate a report or presentation to share with classmates. Their findings will give the entire class a cultural perspective on accident statistical comparisons between different countries.     

The Mixed Media Bag

This article provides basic information on how a common species of earthworm, Eisenia fetida, can be used in the biology classroom as well as a discussion of how to establish and care for a vermicompost bin. We discuss ideas for inquiry activities with the organism and provide a sample-guided inquiry that demonstrates how a long-term, theme-based unit involving earthworms can address a wide variety of content from the National Science Education standards.     

Making the connection: Latino immigrants and their cross-border ties

This paper uses the Pew Hispanic Center's 2006 National Survey of Latinos to study the everyday, routine cross-border activities of travel, remittance sending and telephone communication among Latin American immigrants in the United States. We ask how migrants vary in the intensity of their cross-border connections, distinguishing among the transmigrants, those captured by the host-country national social field, and those who maintain some ongoing home-country tie. We then examine the characteristics associated both with variations in the intensity of connectedness and with each specific type of connection. We show that most migrants maintain some degree of home-country connectedness, with a minority severing ties and a still smaller minority maintaining ties at a high degree of intensity. Connectivity is highly responsive to the location of key social ties, acculturation, and citizenship status, as well as the costs associated with the different types of cross-border activity.     

Geochemistry and Microbial Populations in Sediments of the Northern Baffin Bay,Arctic

The Northern Baffin Bay between Greenland and Canada is a remote Arctic area restricted in primary production by seasonal ice cover, with presumably low sedimentation rates, carbon content and microbial activities in its sediments. Our aim was to study the so far unknown subseafloor geochemistry and microbial populations driving seafloor ecosystems. Shelf sediments had the highest organic carbon content, numbers of Bacteria and Archaea, and microcosms inoculated from Shelf sediments showed highest sulfate reduction and methane production rates. Sediments in the central deep area and on the southern slope contained less organic carbon and overall lower microbial numbers. Similar 16S rRNA gene copy numbers of Archaea and Bacteria were found for the majority of the sites investigated. Sulfate in pore water correlated with dsrA copy numbers of sulfate-reducing prokaryotes and differed between sites. No methane was found as free gas in the sediments, and mcrA copy numbers of methanogenic Archaea were low. Methanogenic and sulfate-reducing cultures were enriched on a variety of substrates including hydrocarbons. In summary, the Greenlandic shelf sediments contain vital microbial communities adapted to their specific environmental conditions.     

Good student questions in inquiry learning

Acquisition of scientific reasoning is one of the big challenges in education. A popular educational strategy advocated for acquiring deep knowledge is inquiry-based learning, which is driven by emerging ‘good questions’. This study will address the question: ‘Which design features allow learners to refine questions while preserving student ownership of the inquiry process?’ This design-based research has been conducted over several years with advanced high-school biology classes. The results confirm the central role of question elaboration as an interactive process that leads from vague to complex and adequate. To make this happen, the inquiry process must extend over a long time, learners and teachers should share a knowledge improvement goal, and text produced by students should be structured by question–answer pairs addressing a single concept using authentic resources. Further features are discussion with peers, teacher feedback with respect to answer elaboration and conceptual differentiation, and finally, teacher guidance that should fade out in successive inquiry cycles to ensure student responsibility.