MOOCs – Lernen im Internet

MOOCs – the next generation of lectures? Massive open online courses (MOOCs) are free internet‐based courses that allow to illustrate topics in an entertaining and vivid way. The number of courses offered is rising rapidly, and a wide range of topics is covered. Our English‐language MOOC “DNA – from structure to therapy” is oriented towards high school students from all over the world who are interested in biology and perhaps plan to pursue a career in the life sciences. Even though the concept of MOOCs has not been perfected yet, they have many advantages. Therefore, MOOCs have the potential to become a permanent part of the global educational landscape.     

The Changing Face of Natural Resources Students,Education, and the Profession

ABSTRACT There are many challenges facing natural resources programs in North American higher education today. Pressures exerted by a new generation of students, changing workplace requirements (including undergraduate core-knowledge requirements), and an increasingly specialized professoriate are great but not insurmountable. We discuss each of these issues and pose potential solutions to address each including adopting new pedagogical techniques for content delivery (e.g., adapting courses to be inclusive of new technologies), revising curriculum to meet the needs of a new suite of learners (e.g., developing curricula that allow structured flexibility of choices, designing a core curriculum that is a mix of single-discipline courses and courses that integrate across disciplines), and new strategies for faculty engagement in discipline-specific survey courses. By remaining deliberate and effective in our pursuit of quality higher education we have the opportunity to ensure we are delivering the best possible education to the future professionals of our disciplines.     

《生物化学》作为通识课的教学实践

生物化学研究生命的化学组成和化学变化等生命基本属性,是阐述生命奥秘的基本语言,是生命科学的基础学科。生物化学能否作为公选课?如果其作为公选课,又应包含哪些生物化学知识,如何讲授这些专业知识?本文从课程内容,教材选取以及授课方式等方面介绍了笔者在向非健康科学专业的学生开设《生物化学》公选课的实践和体会。笔者联系身边的生物化学现象讲解其中的基本生物化学原理,关注疾病发生和临床治疗中涉及的生物化学,整合本校生命和健康相关学科和最前沿的科学进展中涉及到的生物化学知识,极大地增强了学生对生物化学和生命科学的兴趣,有效提高了教学效果;并且为学生理解其它生命科学选修课程打下了良好的基础。这些策略和教学方法对于公选课和通识课,甚至专业课的教学实践,具有一定的参考价值。     

Effect of electrolyte composition of various solutions on potential-sensitive ion channels, formed by syringomycin E in lipid bilayers]

Using the planar lipid bilayer technique, the dependence of properties of ion channels formed by syringomycin E on bath ion composition (electrolyte concentration and pH) and on the applied potential was studied. Time courses of the membrane current in field reversal experiments with 1M NaCl, pH 6 in the bathing solution were similar to the time courses observed with a bathing solution of 0.1 M NaCl, pH 2: there was no increase (decrease) of the membrane current at positive (negative) values of the transmembrane potential. However, kinetic curves were different at 0.1 M. NaCl, pH 6 and pH 9. At pH 6 there was an abrupt increase (decrease) of the membrane current over the time at the positive (negative) values of the applied potential. At pH 9 there was a reversed current response. The results indicate that charged groups are likely to be responsible for opening or closing the channel facing the water phase. Based on these data, a model is proposed describing the potential dependent opening and closing of ion channels formed by syringomycin E.     

Simultaneous analysis of prompt and delayed chlorophyll a fluorescence in leaves during the induction period of dark to light adaptation

An attempt is made to reveal the relation between the induction curves of delayed fluorescence (DF) registered at 0.35-5.5 ms and the prompt chlorophyll fluorescence (PF). A simple formulation was proposed to link the ratio of the transient values of delayed and variable fluorescence with the redox state of the primary electron acceptor of Photosystem II--QA, and the thylakoid membrane energization. The term luminescence potential (UL) was introduced, defined as the sum of the redox potential of QA and the transmembrane proton gradient. It was shown that UL is proportional to the ratio of DF to the variable part of PF. The theoretical model was verified and demonstrated by analysing induction courses of PF and millisecond DF, simultaneously registered from leaves of barley--wild-type and the chlorophyll b-less mutant chlorina f2. A definitive correlation between PF and DF was established. If the luminescence changes are strictly due to UL, the courses of DF and PF are reciprocal and the millisecond DF curve resembles the first derivative of the PFt function.     

Hydraulic vulnerability, vessel refilling, and seasonal courses of stem water potential of Sorbus aucuparia L. and Sambucus nigra L.

Differences in the seasonal variation in stem water potential between the two shrub species Sorbus aucuparia and Sambucus nigra were related with their vulnerability to xylem cavitation. It was also demonstrated indirectly that the two species differ in the extent to which they reverse cavitation. Seasonal variation in stem water potential was investigated during three growing seasons with in situ stem psychrometers. Sorbus experienced wide water potential variations and reached a minimum of -4.2 MPa during drought. Under the same microclimatic conditions, Sambucus experienced consistent stem water potentials with a minimum of -1.7 MPa. The relationship between percentage loss in hydraulic conductivity (PLC) and water potential (hydraulic vulnerability curve) of the two species differed in shape: a flat curve with nearly total loss of conductivity at -6 MPa was found for SORBUS: Sambucus showed a steep vulnerability curve with 90% loss conductivity at -2.2 MPa. Thus, Sambucus is extremely vulnerable to cavitation, but Sorbus is an almost invulnerable species. This different cavitation resistance adjusted the ranges of field stem water potential that the species experienced. Finally, seasonal courses of naturally occurring (native) embolism were compared with calculated PLC courses. This comparison indicates that Sorbus did not refill embolized xylem vessels whereas Sambucus reversed embolism. It was concluded that species which are highly vulnerable to cavitation and drought-induced embolism need refilling of embolized vessels as well as isohydric water potential patterns as two strategies of survival.     

How to do it. Run a preparation course for postgraduate examinations.

This paper provides a practical guide to running preparation courses for postgraduate examinations and is based on the authors'' experience. It is intended to be useful to organisers of proposed or existing courses as well as to potential users of courses--people in every specialty preparing for a postgraduate examination. The paper covers the practical aspects of staging and financing a course and recruiting tutors and attracting candidates, in addition to covering the structure, educational content, and evaluation of the course.     

The Role of Golf Courses in Biodiversity Conservation and Ecosystem Management

We assessed the ecological value of golf courses based on a quantitative synthesis of studies in the scientific literature that have measured and compared biota on golf courses to that of biota in green-area habitats related to other land uses. We found that golf courses had higher ecological value in 64% of comparative cases. This pattern was consistent also for comparisons based on measures of species richness, as well as for comparisons of overall measures of birds and insects—the fauna groups most widely examined in the studies. Many golf courses also contribute to the preservation of fauna of conservation concern. More broadly, we found that the ecological value of golf courses significantly decreases with land types having low levels of anthropogenic impact, like natural and nature-protected areas. Conversely, the value of golf courses significantly increases with land that has high levels of anthropogenic impact, like agricultural and urban lands. From an ecosystem management perspective, golf courses represent a promising measure for restoring and enhancing biodiversity in ecologically simplified landscapes. Furthermore, the review suggests that golf courses hold a real potential to be designed and managed to promote critical ecosystem services, like pollination and natural pest control, providing an opportunity for joint collaboration among conservation, restoration and recreational interests. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. J.C. have designed the study, performed research, the analysis of data and writing the paper, and C.F. has especially contributed to the latter two.     

Quality of use of parenteral metronidazole therapy in a teaching hospital

The recent release, relatively high cost and potential adverse effects of parenterally administered metronidazole prompted a quality-of-use audit at a 1000-bed teaching hospital. Ninety-two courses of treatment in 81 inpatients during a 6-week period were studied. Appropriateness of therapy was assessed on the basis of published indications. Parenterally administered metronidazole was prescribed primarily in anaerobic and anaerobic-aerobic infections. It was used as frequently for prophylaxis as for therapy. Surgical services accounted for 95% of the treatment courses. Inappropriate use was noted in 27 (29%) of the courses: agents other than parenterally administered metronidazole were indicated in 12 (13%), while the dose, dosing interval or duration of treatment was suboptimal in 15 (16%). Substantial savings would be achieved if oral or rectal metronidazole therapy were substituted for intravenous therapy for perioperative prophylaxis in elective colorectal surgery. Written justification for use and automatic stop orders are recommended to improve the cost effectiveness of both prophylactic and therapeutic use of selected antimicrobial agents.     

The use of Beneckea natriegens for practical exercises in microbiology and biochemistry

Beneckea natriegens is a rapidly growing, nonpathogenic marine bacterium which can be used with advantage to replace Escherichia coli in many of the microbiology experiments which are performed in undergraduate courses. Some recommendations for the handling and growth of this organism together with some examples of experiments are described. The potential value of this organism as a subject for student research projects is also discussed.     

Undergraduate animal behavior program: Teaching and research

The purpose of this paper is to present strategies for teaching animal behavior within a mixed traditional and nontraditional format. Based on our experience, it is very useful to use zoological parks as convenient locales for observational studies. Students gain many valuable experiences in a nontraditional course such as this. Various suggestions are made for animal behavior courses and student projects. Some of the potential pitfalls and problems associated with an animal behavior course are also discussed. Finally, future directions are suggested.     

Inner field compensation as a tool for the characterization of asymmetric membranes and Peptide-membrane interactions

Symmetric and asymmetric planar lipid bilayers prepared according to the Montal-Mueller method are a powerful tool to characterize peptide-membrane interactions. Several electrical properties of lipid bilayers such as membrane current, membrane capacitance, and the inner membrane potential differences and their changes can be deduced. The time-resolved determination of peptide-induced changes in membrane capacitance and inner membrane potential difference are of high importance for the characterization of peptide-membrane interactions. Intercalation and accumulation of peptides lead to changes in membrane capacitance, and membrane interaction of charged peptides induces changes in the charge distribution within the membrane and with that to changes in the membrane potential profile. In this study, we establish time-resolved measurements of the capacitance minimization potential DeltaPsi on various asymmetric planar lipid bilayers using the inner field compensation method. The results are compared to the respective ones of inner membrane potential differences DeltaPhi determined from ion carrier transport measurements. Finally, the time courses of membrane capacitances and of DeltaPsi have been used to characterize the interaction of cathelicidins with reconstituted lipid matrices of various Gram-negative bacteria.     

Pseudo-streaming potentials in Necturus gallbladder epithelium. II. The mechanism is a junctional diffusion potential

The mechanisms of apparent streaming potentials elicited across Necturus gallbladder epithelium by addition or removal of sucrose from the apical bathing solution were studied by assessing the time courses of: (a) the change in transepithelial voltage (Vms). (b) the change in osmolality at the cell surface (estimated with a tetrabutylammonium [TBA+]-selective microelectrode, using TBA+ as a tracer for sucrose), and (c) the change in cell impermeant solute concentration ([TMA+]i, measured with an intracellular double-barrel TMA(+)-selective microelectrode after loading the cells with TMA+ by transient permeabilization with nystatin). For both sucrose addition and removal, the time courses of Vms were the same as the time courses of the voltage signals produced by [TMA+]i, while the time courses of the voltage signals produced by [TBA+]o were much faster. These results suggest that the apparent streaming potentials are caused by changes of [NaCl] in the lateral intercellular spaces, whose time course reflects the changes in cell water volume (and osmolality) elicited by the alterations in apical solution osmolality. Changes in cell osmolality are slow relative to those of the apical solution osmolality, whereas lateral space osmolality follows cell osmolality rapidly, due to the large surface area of lateral membranes and the small volume of the spaces. Analysis of a simple mathematical model of the epithelium yields an apical membrane Lp in good agreement with previous measurements and suggests that elevations of the apical solution osmolality elicit rapid reductions in junctional ionic selectivity, also in good agreement with experimental determinations. Elevations in apical solution [NaCl] cause biphasic transepithelial voltage changes: a rapid negative Vms change of similar time course to that of a Na+/TBA+ bi-ionic potential and a slow positive Vms change of similar time course to that of the sucrose-induced apparent streaming potential. We conclude that the Vms changes elicited by addition of impermeant solute to the apical bathing solution are pseudo-streaming potentials, i.e., junctional diffusion potentials caused by salt concentration changes in the lateral intercellular spaces secondary to osmotic water flow from the cells to the apical bathing solution and from the lateral intercellular spaces to the cells. Our results do not support the notion of junctional solute-solvent coupling during transepithelial osmotic water flow.     

浅析微生物学双语教学几个关键问题

专业基础课是衔接大学基础知识和专业知识的重要课程,也是比较难学的课程之一。根据《微生物学》课程的双语教学实践,对生物工程专业的专业基础课中双语教学的教材选择、教学方法、教学内容等几个关键问题展开讨论,并就如何提高双语讲授专业基础课的教学质量进行有益的探讨。     

Next‐generation field courses: Integrating Open Science and online learning

As Open Science practices become more commonplace, there is a need for the next generation of scientists to be well versed in these aspects of scientific research. Yet, many training opportunities for early career researchers (ECRs) could better emphasize or integrate Open Science elements. Field courses provide opportunities for ECRs to apply theoretical knowledge, practice new methodological approaches, and gain an appreciation for the challenges of real‐life research, and could provide an excellent platform for integrating training in Open Science practices. Our recent experience, as primarily ECRs engaged in a field course interrupted by COVID‐19, led us to reflect on the potential to enhance learning outcomes in field courses by integrating Open Science practices and online learning components. Specifically, we highlight the opportunity for field courses to align teaching activities with the recent developments and trends in how we conduct research, including training in: publishing registered reports, collecting data using standardized methods, adopting high‐quality data documentation, managing data through reproducible workflows, and sharing and publishing data through appropriate channels. We also discuss how field courses can use online tools to optimize time in the field, develop open access resources, and cultivate collaborations. By integrating these elements, we suggest that the next generation of field courses will offer excellent arenas for participants to adopt Open Science practices.     

Parameter estimation in Hodgkin-Huxley-Type equations for membrane action potentials in nerve and heart muscle

A method is presented which renders parameter estimation possible in systems of non-linear differential equations where normally no solution exists in terms of analytic functions and which have to be solved numerically. The method uses the concept of sensitivity equations. Two examples are given, taking mathematical models for membrane action potentials in nerve and heart muscle by Hodgkin and Huxley and by Beeler and Reuter. The model equations together with the corresponding system of sensitivity equations are given, which are necessary to estimate maximum conductivity coefficients defining the interactions of different ionic current components. A computer program is described and results of action potential numerical analysis are presented using simulated data. It can be seen, that even with superimposed simulated noise the real parameter values are estimated in an excellent manner. The method can be used to interpret observed changes in action potential time courses under physiological and pharmacological conditions.     

Problem-based learning biotechnology courses in chemical engineering

We have developed a series of upper undergraduate/graduate lecture and laboratory courses on biotechnological topics to supplement existing biochemical engineering, bioseparations, and biomedical engineering lecture courses. The laboratory courses are based on problem-based learning techniques, featuring two- and three-person teams, journaling, and performance rubrics for guidance and assessment. Participants initially have found them to be difficult, since they had little experience with problem-based learning. To increase enrollment, we are combining the laboratory courses into 2-credit groupings and allowing students to substitute one of them for the second of our 2-credit chemical engineering unit operations laboratory courses.     

Leaf conductance and transpiration, and water relations of evergreen and deciduous perennials co-occurring in a moist chaparral site

Abstract. Diurnal courses of leaf conductance, water potential and environmental parameters were measured through the year. The seasonal decreases in plant water potentials were greatest in evergreen H. arbutifolia , intermediate in winter deciduous C. occidentalis and least in drought deciduous A. californica. The seasonal patterns of water use were very similar. Estimates of soil root-stem conductances to liquid water flux indicate that during the spring, conductances are high, that during the early summer there is a daily shift from high morning conductances to lower afternoon conductances, and that late summer conductances are low.     

Factors determining the decay of K+ potentials and focal potentials in the central nervous system.

Post-tetanic undershoots in extracellular focal potential (deltaV) and K+ potential (EK) can be recorded in the cuneate nucleus and dorsal horn of Dial-anaesthetized or decerebrate cat. They are seen best at depths where the largest deltaEK and deltaV are recorded and they increase with the frequency and duration of stimulation. The very different time courses of undershoots of deltaV and deltaEK indicate two hyperpolarizing influences: first, electrogenic pumping, and later, a reduced external K+ concentration. The importance of active K+ removal in determining the amplitude and duration of deltaEK and deltaV is illustrated by their marked potentiation (as well as the disappearance of post-tetanic undershoots) induced by a lowering of blood pressure or local application of strophanthidin.