Computational biology: Turing’s lessons in simplicity

Biophysical modeling of development started with Alan Turing. His two-morphogen reaction-diffusion model was a radical but powerful simplification. Despite its apparent limitations, the model captured real developmental processes that only recently have been validated at the molecular level in many systems. The precision and robustness of reaction-diffusion patterning, despite boundary condition-dependence, remain active areas of investigation in developmental biology.     

Shoot and root proliferation in ‘Williams’ banana: are the topolins better cytokinins?

The effects of five topolins (meta-Topolin?=?mT; meta-Topolin riboside?=?mTR; meta-Methoxy topolin?=?MemT; meta-Methoxy topolin riboside?=?MemTR and meta-Methoxy topolin 9-tetrahydropyran-2-yl?=?MemTTHP) on shoot and root regeneration of micropropagated ??Williams?? bananas were compared to benzyladenine (BA). Sterile shoot-tip explants were cultured on modified Murashige and Skoog (MS) media containing 10, 20 or 30???M of the above cytokinins (CKs) for 42 days. Using shoot regenerated from optimum CK concentration, rooting experiments involving the use of indole-3-acetic acid, indole-3-butyric acid, naphthalene acetic acid, smoke?Cwater (SW) and karrikinolide (KAR₁) were conducted. Apart from 10???M BA and 30???M MemTTHP treatments, the number of shoots produced in all the CK treatments were significantly higher than the control. In addition, 30???M mT resulted in the highest number of shoots (7.3?±?1.0). Unlike other CK treatments requiring higher concentrations, optimum mean shoot number per explant rate was attained at the lowest concentration in MemT and MemTTHP (10???M) treatments. The use of 10???M MemTTHP had the least root inhibitory effect during the shoot proliferation phase. In terms of abnormality index, mTR-regenerated plantlets were of the best quality across all the CKs tested. In mT- and BA-derived shoots, SW and KAR₁ significantly increased the number and length of roots compared to the control. Overall, when compared to BA, the use of topolin demonstrated higher mean shoot number per explant (MemT and MemTTHP) at lowest CK concentrations and the ease of rooting during the shoot proliferation phase (MemTTHP). During the rooting phase, topolin treatments produced more off-shoots than BA-treated ones. The current finding is a further demonstration of the increasing importance of topolins in micropropagation.     

Procedural understanding in biology: the ‘thinking behind the doing’

Several developments in science education aim to improve pupils' ability to ‘think scientifically’. This paper argues for the explicit teaching of the ideas that pupils need to ‘think about’ to do this; ideas related to the design of investigations and the collection, presentation, analysis, and evaluation of the resulting evidence — ideas which are important both for pupils who continue to study or work with biology and for all pupils to become biologically literate. This paper considers some of the concepts of evidence which are particularly important to biology, and discusses how and why the ideas could be taught.     

Histochemistry and cell biology: what’s in a name?

Histochemistry represents an integrative discipline aiming at the in situ detection, localization and functional characterization of cellular and extracellular components in single cells and complex organs. Therefore, the development of new methods and improvement of existing ones continues to be important. This, however, is with the declared intent for their application in the various fields of developmental and cell biology as well as pathology in order to contribute to the solution of open problems. This review summarizes recent advancements in these fields. Accepted: 8 November 1999     

Ineffectiveness of Reverse Wording of Questionnaire Items: Let’s Learn from Cows in the Rain

Objective

We examined the effectiveness of reverse worded items as a means of reducing or preventing response bias. We first distinguished between several types of response bias that are often confused in literature. We next developed arguments why reversing items is probably never a good way to address response bias. We proposed testing whether reverse wording affects response bias with item-level data from the Multidimensional Fatigue Inventory (MFI-20), an instrument that contains reversed worded items.

Methods

With data from 700 respondents, we compared scores on items that were similar with respect either to content or to direction of wording. Psychometric properties of sets of these items worded in the same direction were compared with sets consisting of both straightforward and reversed worded items.

Results

We did not find evidence that ten reverse-worded items prevented response bias. Instead, the data suggest scores were contaminated by respondent inattention and confusion.

Conclusions

Using twenty items, balanced for scoring direction, to assess fatigue did not prevent respondents from inattentive or acquiescent answering. Rather, fewer mistakes are made with a 10-item instrument with items posed in the same direction. Such a format is preferable for both epidemiological and clinical studies.     

Let’s talk about sexes: sex-related N-glycosylation in ecologically important invertebrates

Glycoconjugate Journal - Parasitic helminths and pest insects are organisms with great ecological importance, having direct or indirect detrimental effects on people’s lives worldwide....     

Breeding biology of Western Bonelli’s Warblers Phylloscopus bonelli in the Mediterranean region

Capsule: The Western Bonelli’s Warbler Phylloscopus bonelli has a nest success of only 25% in the core of its range in western Europe.

Aims: To investigate the breeding biology of Western Bonelli’s Warbler P. bonelli, focusing on possible altitude effects and potential reproductive problems.

Methods: Three Western Bonelli’s Warbler populations were monitored during the 2012 and 2013 breeding seasons in the massif range of Sierra Nevada, Spain. We determined all the breeding parameters and calculated daily survival and success rates for each reproductive period.

Results: The three studied populations did not differ in any breeding parameters. Altitude showed a positive relationship with clutch size and duration of incubation period, but a negative relationship with nestling tarsus growth and body mass gain. Daily survival rates during incubation and nestling periods were similar to those of common warblers, but the species presented a low breeding success of 25%.

Conclusion: The absence of differences among the three populations suggests that the information provided here could be representative of its distribution in the woodlands of Sierra Nevada. The novel and detailed information reported is crucial not only for expanding our understanding of this species but also to draw attention to the potential risks that it might face in the near future, considering the reduction that this species has suffered in Sierra Nevada during recent decades.     

Molecular pharming’s foot in the FDA’s door: Protalix’s trailblazing story

Objectives

This short commentary examines the factors that led to Food and Drug Administration’s approval of the first plant-derived biologic.

Results

In 2012, the first plant-derived protein pharmaceutical (biologic) was approved for commercial use in humans. The product, a recombinant form of human β-glucocerebrosidase marketed as ELELYSO, was developed by Protalix Biotherapeutics (Carmiel, Israel). The foresight to select this particular therapeutic product for development, flawless production pipeline, and serendipity seem to provide the key in explaining how ELELYSO became the first plant-derived biologic to achieve approval by Food and Drug Administration.

Conclusions

While the circumstances that enabled Protalix and its scientists to become the first to arrive at this historic milestone are perhaps unique, it is anticipated that more biologics will follow suit in winning regulatory endorsement.