Prospective elementary science teachers’ understanding of photosynthesis and cellular respiration in the context of multiple biological levels as nested systems

In this study, Turkish prospective elementary science teachers’ understanding of photosynthesis and cellular respiration has been analysed within the contexts of ecosystem knowledge, organism knowledge and interconnection knowledge (IK). In the analysis, concept maps developed by 74 prospective teachers were used. The study was carried out with prospective teachers in their final year who were enrolled in the special teaching methods course. The results show that prospective teachers’ understanding of photosynthesis, cellular respiration, energy flow and matter cycling is quite different from one another’s. In addition, the present study revealed that prospective elementary science teachers showed weak understanding of energy flow and matter, cycling and cellular respiration concepts and IK category but they had strong understanding of photosynthesis concept. Prospective teachers also experience difficulties in understanding connections between macro- and microbiological systems. The study concludes with suggestions for more meaningful biology education.     

Using concept maps to characterise cellular respiration knowledge in undergraduate students

ABSTRACT

Meaningful learning occurs by relating new information to and revising prior knowledge, making it essential to understand student knowledge before helping them move toward a more scientific understanding. In this study, we characterise prior knowledge about cellular respiration in undergraduate students enrolled in introductory biology by analysing student-constructed concept maps (N = 182) and interviews (N = 9). Students were instructed to create concept maps from a bank of 20 concepts with the purpose of interconnecting the processes of cellular respiration, showing how pools of ATP are generated and used, and identifying where the events of cellular respiration occur. Student maps were analysed for content, quality and organisation of knowledge. Interviews were used to corroborate inferences made from concept maps. Students had a simplified understanding of cellular respiration and its processes as evident by cognitive structures with limited quantities of schemas that were vaguely connected and linearly organised. Furthermore, students had a better understanding of glycolysis than fermentation. Instructors can use these findings to help students build better knowledge of cellular respiration by focusing on incorporating relevant schemas, creating quality connections among schemas, and organising their knowledge of cellular respiration to reflect biological complexity.     

Spatial compartmentalization of signal transduction in insulin action

Insulin resistance is thought to be the primary defect in the pathophysiology of type 2 diabetes. Thus, understanding the cellular mechanisms of insulin action may contribute significantly to developing new treatments for this disease. Although the effects of insulin on glucose and lipid metabolism are well documented, gaps remain in our understanding of the precise molecular mechanisms of signal transduction for the hormone. One potential clue to understanding the unique cellular effects of insulin may lie in the compartmentalization of signaling molecules and metabolic enzymes. We review this evidence, and speculate on how PI-3 kinase-independent and -dependent signaling pathways both diverge from the insulin receptor and converge at discrete targets to insure the specificity of insulin action.     

Use of brain slices to study long-term potentiation and depression as examples of synaptic plasticity.

Brain slices have been responsible for the majority of advances in our understanding of the cellular aspects of altered synaptic strength underlying memory, long-term potentiation (LTP) and long-term depression (LTD), and increases and decreases, respectively, in synaptic strength at glutamatergic synapses. Our current understanding of LTP and LTD has come largely from studies in hippocampal slices. We consider the strengths and limitations of brain slice technology applied to this subject and conclude that they will continue to have an important role in future studies into the cellular machinery underlying changes in synaptic strength.     

Watching the grin fade: Tracing the effects of polyploidy on different evolutionary time scales

Polyploidy, or whole-genome duplication (WGD), is a recurrent mutation both in cell lineages and over evolutionary time. By globally changing the relationship between gene copy number and other cellular entities, it can induce dramatic changes at the cellular and phenotypic level. Perhaps surprisingly, then, the insights that these events can bring to understanding other cellular features are not as well appreciated as they could be. In this review, we draw on examples of polyploidy from animals, plants and yeast to explore how investigations of polyploid cells have improved our understanding of the cell cycle, biological network complexity, metabolic phenotypes and tumor biology. We argue that the study of polyploidy across organisms, cell types, and time scales serves not only as a window into basic cell biology, but also as a basis for a predictive biology with applications ranging from crop improvement to treating cancer.     

microRNA evolution in a human transcription factor and microRNA regulatory network

Background  

microRNAs (miRNAs) are important cellular components. The understanding of their evolution is of critical importance for the understanding of their function. Although some specific evolutionary rules of miRNAs have been revealed, the rules of miRNA evolution in cellular networks remain largely unexplored. According to knowledge from protein-coding genes, the investigations of gene evolution in the context of biological networks often generate valuable observations that cannot be obtained by traditional approaches.     

Advancing structural biology through breakthroughs in AI

The past century has witnessed an exponential increase in our atomic-level understanding of molecular and cellular mechanisms from a structural perspective, with multiple landmark achievements contributing to the field. This, coupled with recent and continuing breakthroughs in artificial intelligence methods such as AlphaFold2, and enhanced computational power, is enabling our understanding of protein structure and function at unprecedented levels of accuracy and predictivity. Here, we describe some of the major recent advances across these fields, and describe, as these technologies coalesce, the potential to utilise our enhanced knowledge of intricate cellular and molecular systems to discover novel therapeutics to alleviate human suffering.     

Interrelationships amongst radiation-induced genomic instability, bystander effects, and the adaptive response

Over the past two decades, our understanding of radiation biology has undergone a fundamental shift in paradigms away from deterministic "hit-effect" relationships and towards complex ongoing "cellular responses". These responses include now familiar, but still poorly understood, phenomena associated with radiation exposure such as bystander effects, genomic instability, and adaptive responses. All three have been observed at very low doses, and at time points far removed from the initial radiation exposure, and are extremely relevant for linear extrapolation to low doses; the adaptive response is particularly relevant when exposure is spread over a period of time. These are precisely the circumstances that are most relevant to understanding cancer risk associated with environmental and occupational radiation exposures. This review will provide a synthesis of the known, and proposed, interrelationships amongst low-dose cellular responses to radiation. It also will examine the potential importance of non-targeted cellular responses to ionizing radiation in setting acceptable exposure limits especially to low-LET radiations.     

Insights of high-density lipoprotein apolipoprotein-mediated lipid efflux from cells

High-density lipoprotein (HDL) protects against cardiovascular diseases by removal of excess lipids from cells. HDL apolipoprotein-mediated lipid efflux involves multiple cellular proteins to remove both cholesterol and phospholipids that are otherwise stored in the cells. This article reviews recent progress in the understanding of receptors, signal mediators, Golgi and vesicle transport related to the pathway and proposes a model of HDL apolipoprotein receptor-mediated exocytosis of cellular cholesterol. Such an exocytotic pathway could provide the most effective mechanism to remove excess cellular lipids and prevent atherogenesis.     

Genetic analysis of seed coat development in Arabidopsis

In the angiosperms, fertilization initiates the formation of the seed from the ovule, including the differentiation of the seed coat from the ovule integuments. Seed coat differentiation includes some of the most dramatic cellular changes of seed development and culminates in the death of the seed coat cells. Recently, genetic analyses in Arabidopsis have contributed substantially to our understanding of many aspects of seed coat biology and it might not be long before the entire differentiation pathway is understood. Such an advance would contribute substantially to our understanding of many important cellular events, including secondary cell wall synthesis, cell morphogenesis, vacuolar targeting and cell death, and would provide tools for the manipulation of seed dormancy and germination.     

Cellular differentiation in the shoot epidermis

The recent advances in defining genes involved in shoot epidermal cell differentiation are impressive, especially the characterisation of genes involved in cellular patterning. The additional influences of environment and hormones on cellular patterning have recently been emphasised, and important connections have been made to changes in vegetative and reproductive growth phases. Despite these advances the cellular basis for differentiation remains less well defined, but now genetic and cell biological analysis from yeast may provide important models on which to develop further understanding.     

Preparation of Highly Coupled Rat Heart Mitochondria

The function of mitochondria in generation of cellular ATP in the process of oxidative phosphorylation is widely recognised. During the past decades there have been significant advances in our understanding of the functions of mitochondria other than the generation of energy. These include their role in apoptosis, acting as signalling organelles, mammalian development and ageing as well as their contribution to the coordination between cell metabolism and cell proliferation. Our understanding of biological processes modulated by mitochondria is based on robust methods for isolation and handling of intact mitochondria from tissues of the laboratory animals. Mitochondria from rat heart is one of the most common preparations for past and current studies of cellular metabolism including studies on knock-out animals.Here we describe a detailed rapid method for isolation of intact mitochondria with a high degree of coupling. Such preparation of rat heart mitochondria is an excellent object for functional and structural research on cellular bioenergetics, transport of biomolecules, proteomic studies and analysis of mitochondrial DNA, proteins and lipids.     

Decoding photoperiodic time and melatonin in mammals: what can we learn from the pars tuberalis?

The cellular and molecular mechanisms through which the melatonin signal is decoded to drive/synchronize photoperiodic responses remain unclear. Much of our current understanding of the processes involved in this readout derives from studies of melatonin action in the pars tuberalis of the anterior pituitary. Here, the authors review current knowledge and highlight critical gaps in our present understanding.     

Proteomics strategies for protein identification

The information from genome sequencing provides new approaches for systems-wide understanding of protein networks and cellular function. DNA microarray technologies have advanced to the point where nearly complete monitoring of gene expression is feasible in several organisms. An equally important goal is to comprehensive survey cellular proteomes and profile protein changes under different cellular states. This presents a complex analytical problem, due to the chemical variability between proteins and peptides. Here, we discuss strategies to improve accuracy and sensitivity of peptide identification, distinguish represented protein isoforms, and quantify relative changes in protein abundance.     

The emergence of multiple particle tracking in intracellular trafficking of nanomedicines

A growing number of nanoparticle systems, termed “nanomedicines”, are being developed for diagnostic and therapeutic applications. Nanoparticles can employ various cellular entry pathways and trafficking mechanisms to effectively deliver drugs, biomolecules, and imaging agents to precise sub-cellular locations. However, the dynamic transport of nanoparticles through the complex intracellular environment is not well understood, having been primarily studied with static or bulk averaged methods in the past. Such techniques do not provide detailed information regarding the transport mechanism and rates of individual nanoparticles, where understanding of the interaction of nanoparticles with the cellular environment remains incomplete. Recent advances in live-cell fluorescence microscopy and real-time multiple particle tracking (MPT) have facilitated an improved understanding of cell trafficking pathways. Understanding the dynamic transport of nanoparticles as they are delivered into complex cellular components may lead to rational improvements in the design of nanomedicines. This review discusses different cellular uptake and trafficking pathways of nanomedicines, briefly highlights current fluorescence microscopy tools, and provides examples from the recent literature on the use of MPT and its applications.     

Histological analysis of plant regeneration from plumule explants of Cocos nucifera

Plant regeneration was achieved from plumules excised from mature zygotic embryos of a local coconut cultivar (Sri Lanka Tall). A detailed histological study was undertaken to gain a better understanding of the cellular changes that occur during plant regeneration from plumule tissues. This study led to the identification of the cellular origin, specific cell characterization and development pattern of embryogenic calluses. It also revealed that abscisic acid induces plant regeneration through somatic embryogenesis. The presence of incomplete somatic embryos that lacked shoot poles was also observed.     

Preclinical Stroke Research and Translational Failure: A Bird’s Eye View on Preventable Variables

Cellular and Molecular Neurobiology - Despite achieving remarkable success in understanding the cellular, molecular and pathophysiological aspects of stroke, translation from preclinical research...