Category Archives: Life Science

CDC Report on Failures to Vaccinate

Science brought us the miracle of vaccines and the near elimination of many diseases. Unfortunately people are choosing to bring those diseases to many more people because they failed to get vaccinated or failed to vaccinate their children. The needless pain and suffering caused by these poor decisions are a sad testament to scientific illiteracy.

The financial implications of the US measles outbreaks

One reason measles outbreaks are so scary (and so difficult to contain) is that measles is the most infectious microbe known to man–it’s transmission rate is around 90 percent. It has also killed more children than any other disease in history.
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The most significant factor in the spread of measles in the United States is declining vaccination rates — and, similar to what occurred in the UK in the early part of the last decade, that decline can be traced back to the press-fueled panic…

CDC report on Measles

Children and adults who remain unvaccinated and develop measles also put others in their community at risk…

In Europe in recent years, measles has been fatal for several children and adolescents, including some who could not be vaccinated because they were immune compromised.

Rapid control efforts by state and local public health agencies, which are both time intensive and costly, have been a key factor in limiting the size of outbreaks and preventing the spread of measles into communities with increased numbers of unvaccinated persons. Nonetheless, maintenance of high 2-dose MMR vaccination coverage is the most critical factor for sustaining elimination. For measles, even a small decrease in coverage can increase the risk for large outbreaks and endemic transmission, as occurred in the United Kingdom in the past decade…

Nice Program on Mexican Free-tailed Bats

Mexican free-tailed bats in the Central Valley, California: the voracious insect-eating species protects the local crops from pests. Bats really are wonderful animals and very beneficial to people. They eat many insects and some also help pollinate some plants. The Mexican free-tailed bats seem to even benefit from human activity (taking advantage of bridge underpasses as homes, for example), but many other bat species are in trouble.

New Discovery Finds Fungi Different From All Known Forms is Ubiquitous

A New, Somewhat Moldy Branch On The Tree Of Life

Many fungi are already familiar. There are mushrooms, yeasts, molds like the one that makes penicillin, plant diseases such as rusts and smuts. Mildew in your shower is one, along with athlete’s foot. There are even fungi that infect insects — as well as fungi that live on other fungi.

Biologists figure they’ve probably only cataloged about 10 percent of all fungal species. But they thought they at least knew all of the major groups.
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They found novel bits of DNA — related to fungi, but clearly different from all of the known varieties — just about everywhere, “including pond water, lake water, freshwater sediments and marine sediments,” Richards says. “Almost everywhere we looked we found this novel group.”

They then brought samples back to the lab and devised a technique to make the organisms containing this novel DNA glow under a microscope. As a result, they’ve managed to get a few glimpses of these mysterious life forms, which they have named cryptomycota.

“We know they have at least three stages to their life cycle,” Richards says. “One is where they attach to a host, which are photosynthetic algae. Another stage … they form swimming tails so they can presumably find food. And [there’s] another stage, which we call the cyst phase, where they go to sleep.”

Science continues to explore and find new wonders around us. There is so much still to learn.

Evolution of Altruism in Robots

The webcast explores robots evolving cooperative behavior. A Quantitative Test of Hamilton’s Rule for the Evolution of Altruism (open access paper)

One of the enduring puzzles in biology and the social sciences is the origin and persistence of altruism, whereby a behavior benefiting another individual incurs a direct cost for the individual performing the altruistic action. This apparent paradox was resolved by Hamilton’s theory, known as kin selection, which states that individuals can transmit copies of their own genes not only directly through their own reproduction but also indirectly by favoring the reproduction of kin, such as siblings or cousins. While many studies have provided qualitative support for kin selection theory, quantitative tests have not yet been possible due to the difficulty of quantifying the costs and benefits of helping acts. In this study, we conduct simulations with the help of a simulated system of foraging robots to manipulate the costs and benefits of altruism and determine the conditions under which altruism evolves.

By conducting experimental evolution over hundreds of generations of selection in populations with different costs and benefits of altruistic behavior, we show that kin selection theory always accurately predicts the minimum relatedness necessary for altruism to evolve. This high accuracy is remarkable given the presence of pleiotropic and epistatic effects, as well as mutations with strong effects on behavior and fitness. In addition to providing a quantitative test of kin selection theory in a system with a complex mapping between genotype and phenotype, this study reveals that a fundamental principle of natural selection also applies to synthetic organisms when these have heritable properties.

Image of Map Showing Concentration of Life in Oceans

This image shows the abundance of life in the sea, measured by the SeaWiFS instrument aboard the Seastar satellite. Dark blue represents warmer areas where there is little life due to lack of nutrients, and greens and reds represent cooler nutrient-rich areas.

The nutrient-rich areas include coastal regions where cold water rises from the sea floor bringing nutrients along and areas at the mouths of rivers where the rivers have brought nutrients into the ocean from the land. NASA has posted a large gallery of great images for Earth Day.

Cancer Vaccines

A reader commented on a previous post (MIT Engineers Design New Type of Nanoparticle for Vacines) asking about how vaccines can fight cancer. Preventative vaccines can build up immune response to viruses which cause cancer. So the vaccine actually works against the virus which prevents the virus from causing cancer.

The U.S. Food and Drug Administration (FDA) has approved two vaccines, GardasilÂ® and CervarixÂ®, that protect against infection by the two types of human papillomavirus (HPV) – types 16 and 18 – that cause approximately 70% of all cases of cervical cancer worldwide. At least 17 other types of HPV are responsible for the remaining 30% of cervical cancer cases. HPV types 16 and/or 18 also cause some vaginal, vulvar, anal, penile, and oropharyngeal cancers.

Many scientists believe that microbes cause or contribute to between 15% and 25% of all cancers diagnosed worldwide each year, with the percentages being lower in developed than developing countries.

Vaccines can also help stimulate the immune system to fight cancers.

B cells make antibodies, which are large secreted proteins that bind to, inactivate, and help destroy foreign invaders or abnormal cells. Most preventive vaccines, including those aimed at hepatitis B virus (HBV) and human papillomavirus (HPV), stimulate the production of antibodies that bind to specific, targeted microbes and block their ability to cause infection. Cytotoxic T cells, which are also known as killer T cells, kill infected or abnormal cells by releasing toxic chemicals or by prompting the cells to self-destruct (a process known as apoptosis).

Other types of lymphocytes and leukocytes play supporting roles to ensure that B cells and killer T cells do their jobs effectively. These supporting cells include helper T cells and dendritic cells, which help activate killer T cells and enable them to recognize specific threats.

Cancer treatment vaccines are designed to work by activating B cells and killer T cells and directing them to recognize and act against specific types of cancer. They do this by introducing one or more molecules known as antigens into the body, usually by injection. An antigen is a substance that stimulates a specific immune response. An antigen can be a protein or another type of molecule found on the surface of or inside a cell.

How To Make Your Own Pesticide with Ingredients from Your Kitchen

Video by the Singapore National Park Board, on creating your own pesticide with just water, dish-washing liquid, chili, garlic and cooking oil.

New Analysis of Primordial Soup Experiment Half a Century Later

Open access paper: Primordial synthesis of amines and amino acids in a 1958 Miller H₂S-rich spark discharge experiment

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H₂S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H₂S, CH₄, NH₃, and CO₂. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples.

The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment.

The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H₂S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H₂S may have played an important role in prebiotic reactions in early solar system environments.

Diet May Help ADHD Kids More Than Drugs

Kids with ADHD can be restless and difficult to handle. Many of them are treated with drugs, but a new study says food may be the key. Published in The Lancet journal, the study suggests that with a very restrictive diet, kids with ADHD could experience a significant reduction in symptoms.

The study’s lead author, Dr. Lidy Pelsser of the ADHD Research Centre in the Netherlands, writes in The Lancet that the disorder is triggered in many cases by external factors — and those can be treated through changes to one’s environment. “ADHD, it’s just a couple of symptoms — it’s not a disease,” the Dutch researcher tells All Things Considered weekend host Guy Raz.

The way we think about — and treat — these behaviors is wrong, Pelsser says. “There is a paradigm shift needed. If a child is diagnosed ADHD, we should say, ‘OK, we have got those symptoms, now let’s start looking for a cause.’ ”
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According to Pelsser, 64 percent of children diagnosed with ADHD are actually experiencing a hypersensitivity to food. Researchers determined that by starting kids on a very elaborate diet, then restricting it over a few weeks’ time. “It’s only five weeks,” Pelsser says. “If it is the diet, then we start to find out which foods are causing the problems.”

Teachers and doctors who worked with children in the study reported marked changes in behavior. “In fact, they were flabbergasted,” Pelsser says.

Evidence of Extraterrestrial Life Discovered?

Has evidence of extraterrestrial life been discovered? In Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites , Richard B. Hoover, Ph.D. NASA/Marshall Space Flight Center, puts forth his evidence on the discovery of evidence of cyanobacteria in meteorites.

Dr. Hoover has discovered evidence of microfossils similar to Cyanobacteria, in freshly fractured slices of the interior surfaces of the Alais, Ivuna, and Orgueil CI1 carbonaceous meteorites. Based on Field Emission Scanning Electron Microscopy (FESEM) and other measures, Dr. Hoover has concluded they are indigenous to these meteors and are similar to trichomic cyanobacteria and other trichomic prokaryotes such as filamentous sulfur bacteria. He concludes these fossilized bacteria are not Earthly contaminants but are the fossilized remains of living organisms which lived in the parent bodies of these meteors, e.g. comets, moons, and other astral bodies. The implications are that life is everywhere, and that life on Earth may have come from other planets.

The importance of this claim is hard to ignore. The journal includes a statement from Dr. Rudy Schild, Center for Astrophysics, Harvard-Smithsonian, Editor-in-Chief, Journal of Cosmology:

Dr. Richard Hoover is a highly respected scientist and astrobiologist with a prestigious record of accomplishment at NASA. Given the controversial nature of his discovery, we have invited 100 experts and have issued a general invitation to over 5000 scientists from the scientific community to review the paper and to offer their critical analysis. Our intention is to publish the commentaries, both pro and con, alongside Dr. Hoover’s paper. In this way, the paper will have received a thorough vetting, and all points of view can be presented. No other paper in the history of science has undergone such a thorough analysis, and no other scientific journal in the history of science has made such a profoundly important paper available to the scientific community, for comment, before it is published. We believe the best way to advance science, is to promote debate and discussion.

Read the full paper.

The filaments have been observed to be embedded in freshly fractured internal surfaces of the stones. They exhibit features (e.g., the size and size ranges of the internal cells and their location and arrangement within sheaths) that are diagnostic of known genera and species of trichomic cyanobacteria and other trichomic prokaryotes such as the filamentous sulfur bacteria. ESEM and FESEM studies of living and fossil cyanobacteria show similar features in uniseriate and multiseriate, branched or unbranched, isodiametric or tapered, polarized or unpolarized filaments with trichomes encased within thin or thick external sheaths. Filaments found in the CI1 meteorites have also been detected that exhibit structures consistent with the specialized cells and structures used by cyanobacteria for reproduction (baeocytes, akinetes and hormogonia), nitrogen fixation (basal, intercalary or apical heterocysts) and attachment or motility (fimbriae).
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These studies have led to the conclusion that the filaments found in the CI1 carbonaceous meteorites are indigenous fossils rather than modern terrestrial biological contaminants that entered the meteorites after arrival on Earth. The Î´13C and D/H content of amino acids and other organics found in these stones are shown to be consistent with the interpretation that comets represent the parent bodies of the CI1 carbonaceous meteorites. The implications of the detection of fossils of cyanobacteria in the CI1 meteorites to the possibility of life on comets, Europa and Enceladus are discussed.

Has life been found in a meteorite? by Phil Plait
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