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Pollination with Precision: How Flowers Do It

By Guest PostMay 23, 2012Naturearabidopsis plants, brown university, chaotic frenzy, female gametes, fertilization, gamete fusion, hap2, kristin beale, logistical efficiency, mark johnson, mechanism, microscope, model, mothers day, mutant sperm, ovule, pollen grains, pollen tubes, pollination, polytubey, precision, reproduction, sex cells, sperm

Pollination could be a chaotic disaster. With hundreds of pollen grains growing long tubes to ovules to deliver their sperm to female gametes, how can a flower ensure that exactly two fertile sperm reach every ovule? In a new study, Brown University biologists report the discovery of how plants optimize the distribution of pollen for successful reproduction.

PROVIDENCE, R.I. [Brown University] — Next Mother’s Day, say it with an evolved model of logistical efficiency — a flower. A new discovery about how nature’s icons of romance manage the distribution of sperm among female gametes with industrial precision helps explain why the delicate beauties have reproduced prolifically enough to dominate the earth.

In pollination, hundreds of sperm-carrying pollen grains stick to the stigma suspended in the middle of a flower and quickly grow a tube down a long shaft called a style toward clusters of ovules, which hold two female sex cells. This could be a chaotic frenzy, but for the plant to succeed, exactly two fertile sperm should reach the two cells in each ovule — no more, no less. No ovule should be left out, either because too many tubes have gone elsewhere, or because the delivered sperm don’t work. (more…)

Pigeons’ Homing Skill Not Down to Iron-Rich Beak Cells

By Guest PostApril 16, 2012Natureballs of iron, beaks, david keays, electrical signal, Environment, imaging technique, infection, iron, macrophages, magnetic cell, magnetic field, magnetic nerve cell, mark lythgoe, mechanism, migratory bird, navigation, nerve cell, pigeon, red blood cell, state-of-the-art, theory, university college london, vienna, white blood cell

The theory that pigeons’ famous skill at navigation is down to iron-rich nerve cells in their beaks has been disproved by a new study published in Nature.

The study shows that iron-rich cells in the pigeon beak are in fact specialised white blood cells, called macrophages. This finding, which shatters the established dogma, puts the field back on course as the search for magnetic cells continues. (more…)

Researchers Uncover How New Melanoma Drug Accelerates Secondary Skin Cancers

By Guest PostJanuary 20, 2012Healthantoni ribas, braf mutation, cancer growth, cancer mutation, cancer treatment, drug, hematology, malignant cells, mechanism, mek inhibitor, melanoma cells, metastatic melanoma, mutated braf protein, mutation, oncogenic mutations, oncology, patients, plexxikon, ras mutation, roche, ruby family foundation, seaver institute, secondary skin cancers, side effect, skin squamous cell carcinomas, vemurafenib, zelboraf

Patients with metastatic melanoma taking the recently approved drug vemurafenib (marketed as Zelboraf) responded well to the twice-daily pill, but some of them developed a different, secondary skin cancer.

Now, researchers at UCLA’s Jonsson Comprehensive Cancer Center, working with investigators from the Institute of Cancer Research in London, Roche and Plexxikon, have elucidated the mechanism by which the drug excels at fighting melanoma but also allows for the development of skin squamous-cell carcinomas. (more…)

Change in Temperature Uncovers Genetic Cross Talk in Plant Immunity

By Guest PostNovember 17, 2010Nature, Sciencearabidopsis thaliana, avrrps4, bacterial infection, bacterial invaders, bacterial pathogen, cell, cross talk, disease, effector proteins, immune system, mechanism, pathogen, plant proteins, plants, proteins, pseudomonas syringae, resistance proteins, saikat bhattacharjee, sang hee kim, srfr1, walter gassmann

*University of Missouri investigators’ discovery sheds light on how plants fight off bacterial infections*

Columbia, MO — Like us, plants rely on an immune system to fight off disease. Proteins that scout out malicious bacterial invaders in the cell and communicate their presence to the nucleus are important weapons in the plant’s disease resistance strategy. Researchers at the University of Missouri recently “tapped” into two proteins’ communications with the nucleus and discovered a previously unknown level of cross talk. The discovery adds important new information about how plant proteins mediate resistance to bacteria that cause disease and may ultimately lead to novel strategies for boosting a plant’s immune system.

Special proteins in the plant, called resistance proteins, can recognize highly specific features of proteins from pathogen, called effector proteins. When a pathogen is detected, a resistance protein triggers an “alarm” that communicates the danger to the cell’s nucleus. The communication between the resistance protein and nucleus occurs through a mechanism called a signaling pathway. (more…)

Tag Archives: mechanism

Pollination with Precision: How Flowers Do It

Pigeons’ Homing Skill Not Down to Iron-Rich Beak Cells

Researchers Uncover How New Melanoma Drug Accelerates Secondary Skin Cancers

Change in Temperature Uncovers Genetic Cross Talk in Plant Immunity