Welcome to The Visible Embryo

Home- - -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- News Alerts -Contact

Welcome to The Visible Embryo, a comprehensive educational resource on human development from conception to birth.

The Visible Embryo provides visual references for changes in fetal development throughout pregnancy and can be navigated via fetal development or maternal changes.

The National Institutes of Child Health and Human Development awarded Phase I and Phase II Small Business Innovative Research Grants to develop The Visible Embryo. Initally designed to evaluate the internet as a teaching tool for first year medical students, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than ' million visitors each month.


WHO International Clinical Trials Registry Platform
The World Health Organization (WHO) has created a new Web site to help researchers, doctors and patients obtain reliable information on high-quality clinical trials. Now you can go to one website and search all registers to identify clinical trial research underway around the world!



Home

History

Bibliography

Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System

Contact The Visible Embryo

News Alerts Archive

Disclaimer: The Visible Embryo web site is provided for your general information only. The information contained on this site should not be treated as a substitute for medical, legal or other professional advice. Neither is The Visible Embryo responsible or liable for the contents of any websites of third parties which are listed on this site.
Content protected under a Creative Commons License.

No dirivative works may be made or used for commercial purposes.

Return To Top Of Page
Pregnancy Timeline by SemestersFemale Reproductive SystemFertilizationThe Appearance of SomitesFirst TrimesterSecond TrimesterThird TrimesterFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterDevelopmental Timeline
Click weeks 0 - 40 and follow fetal growth
Search artcles published since 2007

July 11, 2012--------News Archive Return to: News Alerts


African trypanosomiasis parasite (dark pink) in blood sample.

WHO Child Growth Charts

       

Researchers Unravel Secrets of Parasites’ Replication

A group of diseases caused by parasites kill millions of people each year can’t be touched by antibiotics, and some treatment is so harsh the patient can’t survive it

For decades researchers have searched for a “magic bullet” to kill parasites without harming the patient. Now, a team of microbiologists at the University of Massachusetts Amherst has made an advance that could one day lead to a new weapon for fighting parasitic diseases such as African sleeping sickness, chagas disease and leishmaniasis.

In the cover article of the current issue of Eukaryotic Cell, parasitologists Michele Klingbeil, doctoral candidate Jeniffer Concepción-Acevedo and colleagues report the first detailed characterization of the way key proteins in the model parasite Trypanosoma brucei organize to replicate its mitochondrial DNA (mtDNA). Understanding this spatial and temporal coordination could mean a foot in the door to launch new attacks on one of the parasites’ essential cell processes, Klingbeil says.

She adds, “Parasites such as T. brucei, which causes African sleeping sickness, are not straightforward to treat because they’re too much like our own cells. Antibiotics are ineffective, so we treat them as invaders, with toxic chemicals. We are trying to find their weaknesses so we can exploit those and eventually develop a very selective, effective and acceptable treatment.”

Advances have not come easily, in part because these parasites have the most complex mitochondrial genome structure in nature, say Klingbeil and Concepción-Acevedo, the lead researcher on the project. To tackle it, they’ve focused on the trypanosome parasites’ extremely complex method of mtDNA replication, which involves kinetoplast DNA or kDNA. Its core components are very unlike DNA replication in animals and human hosts, Klingbeil says, “so if we can inhibit the replication process and take away the kDNA, the parasites will die. That’s one way we might be able to kill them.”


Trypanosomes’ kDNA is found as a nucleoid in
the mitochondrion, where it holds many copies of
catenated, or networked, minicircles and maxicircles
that look like medieval chain mail under the microscope.

These molecules pass information on to daughter cells
via DNA polymerases whose job it is to copy all circles
in the network. Trypanosomes have six mtDNA
polymerases, while humans have just one.


To figure out how these trypanosomal polymerases know when to initiate DNA replication, Concepción-Acevedo set up immuno-fluorescence experiments focused on tracking a particular one, known as mtDNA polymerase ID (POLID).

By making the POLID protein fluorescent, and tracking it over space and time, Concepción-Acevedo quantified it and clarified its relationship in the replication process for the first time - in a very discrete time window. The approach immediately paid off.

Klingbeil says, “As soon as Jeny began looking more closely at POLID localization she discovered a novel mechanism for how this protein participates in kDNA replication.”

In response to kDNA changes during the replication cycle, POLID was dynamically redistributing, or changing location, from the mitochondrial matrix to concentrated foci around the kDNA, and co-localizing with replicating kDNA molecules.

“This had been hypothesized, but never seen before,” Klingbeil explains. It was amazing to witness. We visualized a mitochondrial replication protein undergoing dynamic localization for the first time, and linked it to DNA synthesis. No one had ever been able to do that in any mitochondrial DNA replication system before.”

This important discovery explains how POLID engages in kDNA replication and opens up new avenues to study and intervene in mitochondrial protein dynamics, say the two parasitologists. Their ultimate success would be to find a chemical to inhibit POLID from carrying out its role during replication and target all parasites with kDNA structures.

This work was funded by the National Institutes of Health’s National Institute of Allergy and Infectious Diseases. Support for Concepción-Acevedo also came from NSF’s Northeast Alliance for Graduate Education and the Professoriate program.

Original article: http://www.umass.edu/newsoffice/umass-amherst-researchers-unravel-secrets-parasites’-replication