An ultrastructural study of spermatogenesis and the mature spermatozoon of the ascidian Pyura stolonifera

In Pyura stolonifera, there is an orderly arrangement of the male germ cells within the testicular follicles. Cells in early stages are located at the outer surface of the follicle while those in later stages of differentiation, including mature spermatozoa, lie nearer to the lumen. Developing spermatocytes are connected by cytoplasmic bridges which persist up to the late spermatid stage. The cytoplasmic bridge is reinforced on each side by an osmiophilic layer. Microtubules appear in the cytoplasm around the outside of the nuclear membrane in the mid-spermatid stage. The mature spermatozoon consists of an elongate, spindle-shaped head and a long tail. The head, which is about 9 µm in length, is slightly curved and tapers anteriorly. It comprises an elongate, eleclron-dense nucleus, a single large mitochondrion and a thin layer of cytoplasm. There is no middle piece. The mitochondrion is disposed lateral to the nucleus. Granules (presumably glycogen) occur in the cytoplasm between the nucleus and the mitochondrion. Neither an acrosome nor any other structure corresponding to it was observed in sections of the apical region. A ‘fuzzy’ material, however, surrounds the apex. The tail is about 40 µm in length and 0.2 µm in diameter. The axoneme has the 9 + 2 arrangement of microtubules

Designing a course model for distance-based online bioinformatics training in Africa: the H3ABioNet experience

Africa is not unique in its need for basic bioinformatics training for individuals from a diverse range of academic backgrounds. However, particular logistical challenges in Africa, most notably access to bioinformatics expertise and internet stability, must be addressed in order to meet this need on the continent. H3ABioNet (www.h3abionet.org), the Pan African Bioinformatics Network for H3Africa, has therefore developed an innovative, free-of-charge "Introduction to Bioinformatics" course, taking these challenges into account as part of its educational efforts to provide on-site training and develop local expertise inside its network. A multiple-delivery±mode learning model was selected for this 3-month course in order to increase access to (mostly) African, expert bioinformatics trainers. The content of the course was developed to include a range of fundamental bioinformatics topics at the introductory level. For the first iteration of the course (2016), classrooms with a total of 364 enrolled participants were hosted at 20 institutions across 10 African countries. To ensure that classroom success did not depend on stable internet, trainers pre-recorded their lectures, and classrooms downloaded and watched these locally during biweekly contact sessions. The trainers were available via video conferencing to take questions during contact sessions, as well as via online "question and discussion" forums outside of contact session time. This learning model, developed for a resource-limited setting, could easily be adapted to other settings.IS

Africa: sequence 100,000 species to safeguard biodiversity

Build a major genomics resource on the continent to help breeders and conservationists

Pre-recorded lectures.

<p>Screenshot of a pre-recorded lecture with webcam activated. Note: Consent to publish this image was obtained from the individual in the figure.</p

Screenshots of Vula site for IBT_2016 course.

<p>(A) Landing page of course site showing all tools. (B) Forums tool specifically showing the number of people that read the response to a particular question. In this example, at the time that the screenshot was obtained, 14 people had read the question, and 12 people had read the answer. Please note: Consent to publish this screenshot was obtained from participants of the relevant discussion. Abbreviation: IBT, Introduction to Bioinformatics.</p

Virtual classroom using the Mconf web conferencing platform.

<p>Classrooms connected to the trainer and to other classrooms via the Mconf open-source web conferencing platform (<a href="http://mconf.org/" target="_blank">http://mconf.org</a>; in use here is the South African instance of Mconf <a href="https://mconf.sanren.ac.za/" target="_blank">https://mconf.sanren.ac.za/</a>, hosted by SANREN <a href="http://www.sanren.ac.za/south-african-nren/" target="_blank">http://www.sanren.ac.za/south-african-nren/</a>). Classrooms either activated their microphones or entered text into a chat box to ask questions to the trainer. Trainers activated their webcams while answering questions. Trainers were able to upload their session resources in the central panel of the Mconf interface should they have wanted to explain a concept on a particular lecture slide, for example. Note: Consent to publish this image was obtained from the trainer shown in the figure. Abbreviation: SANREN, South African National Research Network.</p

Location of classroom sites for 2016 iteration of the IBT course.

<p>Classrooms (20 classrooms across 10 African countries accommodating 364 participants in total) met each other virtually to widen the scope and improve the depth of biweekly contact sessions. Abbreviation: IBT, Introduction to Bioinformatics.</p