Cytoskeletal Components of an Invasion Machine—The Apical Complex of Toxoplasma gondii

The apical complex of Toxoplasma gondii is widely believed to serve essential functions in both invasion of its host cells (including human cells), and in replication of the parasite. The understanding of apical complex function, the basis for its novel structure, and the mechanism for its motility are greatly impeded by lack of knowledge of its molecular composition. We have partially purified the conoid/apical complex, identified ~200 proteins that represent 70% of its cytoskeletal protein components, characterized seven novel proteins, and determined the sequence of recruitment of five of these proteins into the cytoskeleton during cell division. Our results provide new markers for the different subcompartments within the apical complex, and revealed previously unknown cellular compartments, which facilitate our understanding of how the invasion machinery is built. Surprisingly, the extreme apical and extreme basal structures of this highly polarized cell originate in the same location and at the same time very early during parasite replication

Learners of a New Generation

To identify educational practices that will best facilitate the development of expertise, we must first understand the learner. Student cohorts in post K-12 education are generally composed of learners from multiple generations. Learning cohorts from previous generations who were accustomed to a limited range of educational resources acclimated to learning through primarily aural and read/write modalities. The educational environment for millennial generation learners has been dominated by technology. As a result a variety of learning styles, not apparent in previous generations, have become common. These learning styles are incidental to novel resources to which learners now have access. Strategies designed to promote successful knowledge acquisition for learners of any style should incorporate a variety of the ever-increasing array of available innovative educational paradigms and digital resources. In addition to resources, other factors that should be considered in the design of strategies which can influence the success of next generation learning include their (1) tendency to learn via real-world applications, (2) unfamiliarity with educational technology, (3) weakness in information literacy, (4) need for frequent feedback, and (5) predilection to work in teams. A multifactorial approach to facilitate the development of expertise will best support individual scholarly effort and preparation for lifelong learning

Evidence for a conserved myogenic program

An invariant, temporal sequence in the accumulation of muscle specific proteins is described, based on studies of nascent, postmitotic, mononucleated myoblasts from three chick skeletal muscle systems; (1) cultured breast muscle, (2) in vivo myotome and (3) in vivo limb. Desmin was the first muscle specific protein found, followed by titin and shortly thereafter, coordinately, by a cohort of myofibrillar proteins. The myofibrillar proteins were first detected in the form of small, irregularly shaped aggregates. Although titin appeared just prior to the other myofibrillar proteins, in this aggregate form, it was not detected as organized filaments earlier than the others. It is therefore unlikely that titin can act as a scaffold in sarcomere formation. If titin acted in this capacity, it would be expected to be exist as a filament earlier than the other myofibrillar proteins, in order that they could assemble upon it. The accumulation and assembly of these proteins was also found to be independent of fusion. In all three of the systems examined, unfused myoblasts were found which contained sarcomeres, identical to those found in adult muscle, already assembled into myofibril. Mononucleated cells were able to synthesize and assemble myofibrillar proteins without the prerequisite of fusion. Although newly born in vivo myoblasts in both myotome and limb displayed the muscle specific protein sequence already described, the source of the precursors of these cells has been a question of considerable interest. Are these precursor cells already postmitotic myoblasts or are they still replicating cells? The myotome proper was found to contain cells that were desmin +/myofibrillar protein +. However, a region identical in each somite--the dorsalmost portion of the somite--displayed cells that were desmin +/myofibrillar protein $-$. These desmin +/myofibrillar protein--cells suggest a local pool of replicating myoblasts. Limb stained for desmin, indicated the cells that invest the limb are not as yet differentiated myoblasts. At no stage at which somitic cells have been found to invest the limb were cells that were desmin + found to extend from the ventral aspect of the somite to the limb

A Novel Way to Engage Medical Students in Learning Gross Anatomy at the Philadelphia College of Osteopathic Medicine

There is no abstract for this article

Localization of Laminin Relative to Alpha 1 Integrin in Embryonic Chick Skeletal Muscle

Background:The spatial and temporal localization of laminin in relation to alpha 1 integrin is examined in chick skeletal muscle. Periodic colocalization of alpha 1 integrin and laminin have previously been observed on myofibers in cultured embryonic chick skeletal muscle as early as day 3 in culture. Similar to the spatial localization found in cultured skeletal muscle, alpha 1 integrin is found with a periodic sarcomeric distribution in sectioned skeletal muscle from chick embryos beginning on embryonic day 13

Preparation of Chick Striated Muscle Cultures

The maturation of striated muscle in primary cultures closely parallels the formation of striated muscle in vivo. Primary cultures thus serve as model systems for the study and manipulation of various aspects of muscle development including the regulation of gene expression, myofibril assembly, myocyte fusion, and myotube contraction. The following protocols provide instructions for the preparation of skeletal muscle cultures from either day 10 embryonic pectoralis muscle or day 2 somites and segmental plate mesoderm. Both methods will yield well-striated, multinucleated, contracting myotubes (Fig. 1) (1–4). Also included is a protocol for the preparation of cardiac cultures from day 7 embryonic heart. This method will yield well-striated, contracting cardiomyocytes (Fig. 1) (5,6)

Demystifying the Millennial Student: A Reassessment in Measures of Character and Engagement in Professional Education

The characteristic profile of Millennial Generation students, driving many educational reforms, can be challenged by research in a number of fields including cognition, learning style, neurology, and psychology. This evidence suggests that the current aggregate view of the Millennial student may be less than accurate. Statistics show that Millennial students are considerably diverse in backgrounds, personalities, and learning styles. Data are presented regarding technological predilection, multitasking, reading, critical thinking, professional behaviors, and learning styles, which indicate that students in the Millennial Generation may not be as homogenous in fundamental learning strategies and attitudes as is regularly proposed. Although their common character traits have implications for instruction, no available evidence demonstrates that these traits impact their fundamental process of learning. Many curricular strategies have been implemented to address alleged changes in the manner by which Millennial students learn. None has clearly shown superior outcomes in academic accomplishments or developing expertise for graduating students and concerns persist related to the successful engagement of Millennial students in the process of learning. Four factors for consideration in general curricular design are proposed to address student engagement and optimal knowledge acquisition for 21st century learners

Clinical Competencies and the Basic Sciences: An Online Case Tutorial Paradigm for Delivery of Integrated Clinical and Basic Science Content

Understanding the relevance of basic science knowledge in the determination of patient assessment, diagnosis, and treatment is critical to good medical practice. One method often used to direct students in the fundamental process of integrating basic science and clinical information is problem-based learning (PBL). The faculty facilitated small group discussion format traditionally used for PBL is a significant challenge for faculty and facilities with a large class. To provide inductive learning to a large class early in the preclerkship curriculum, a series of online, case-based tutorials was created using the method of inquiry-based learning. The tutorial paradigm is designed to challenge students through a guided inquiry process in which clinical skills and basic science information are seamlessly joined. The psychosocial dimension of patient care is added to the documented case presentation of the tutorials in the form of patient/physician history taking and physical examination videos. These videos augment the written case with additional information providing the student with visual exposure in methods of patient communication and appropriate professional patient/physician interactions that address competencies of patient care, communication, and professionalism. The tutorials were made available via learning management system course sites. The study tracked usage of the tutorials by 270 first-year medical students