Tag Archives: fertilization

Pistil leads pollen in life-and-death dance

By Guest PostJuly 17, 2013Nature, Sciencealexander leydon, biomolecular tango, brown university, cross breeding, female ovule, fertilization, flowers, karolina woroniecka, kristin beale, life on earth, male pollen tube, mark johnson, pistil, pollination, protein, reproduce, reproductive system, sex lives, sperm carrying pollen, stigma, thionin

Pollination, essential to much of life on earth, requires the explosive death of the male pollen tube in the female ovule. In new research, Brown University scientists describe the genetic and regulatory factors that compel the male’s role in the process. Finding a way to tweak that performance could expand crop cross-breeding possibilities.

PROVIDENCE, R.I. [Brown University] — Millions of times on a spring day there is a dramatic biomolecular tango where the flower, rather than adorning a dancer’s teeth, is the performer. In this dance, the female pistil leads, the male pollen tubes follow, and at the finish, the tubes explode and die. A new paper in Current Biology describes the genetically prescribed dance steps of the pollen tube and how their expression destines the tube for self-sacrifice, allowing flowering plants to reproduce. (more…)

Easy come, easy grow

By Guest PostMay 25, 2013Scienceamir sanati nezhad, angioplasty, anja geitmann, concordia university, delivery organ, egg cell, elastic polymer material, female tissue, fertilization, force, growing embryo, lithography techniques, loc, mahsa naghavi, male gametophyte, mechanical modeling, micrometer, microsystems engineers, muthukumaran packirisamy, nano, petri dish, placenta, pollen grain, pollen tubes, receptive flower, single cell organ, sperm cell, sperm cell fertilizes, university of montreal

Sperm cell release can be triggered by tightening the grip around the delivery organ, according to a team of nano and microsystems engineers and plant biologists at the University of Montreal and Concordia University. Concordia’s nanobiotech team devised a microchip that enabled the University of Montreal biologists to observe what happened when pollen tubes – the sperm delivery tools used by plants – tried to negotiate a microscopic obstacle course. The pollen tubes were exposed to a series of narrow, elastic openings resulting in a variety of cellular responses. When the opening was too narrow or tight, pollen tube growth stalled. However, the elongating tubes successfully penetrated slightly larger openings. Curiously, the pollen tubes burst and released the sperm cells when passing openings of a particular size relative to the pollen tube width. (more…)

UCLA researchers discover sperm move along a ‘twisting ribbon’

By Guest PostApril 30, 2013Healthaydogan ozcan, chemicals, chemo attractants, chiral ribbon patterns, euan mcleod, fertilization, flagella propel, functions, holographic microscope, horse sperm cells, human, inkyum choi, jaiwen feng, kalvin huang, micro swimmers, micrometers, microscale motion, migration of cells, sperm, sperm cells, sperm head, sperm motility, sperm motion, swimming patterns, ting wei su, toxins, twisted ribbon pattern, twisting ribbon, ucla researchers

Opening the door to more sophisticated investigation of sperm locomotion and biophysics, researchers from UCLA’s Henry Samueli School of Engineering and Applied Science have identified previously unobserved swimming patterns in human and horse sperm cells.

This research, published in Scientific Reports, a journal of the Nature Publishing Group, could lead to a deeper understanding of how sperm move on their way to fertilization or other functions and how they react when encountering various toxins or chemicals. (more…)

NASA Maps How Nutrients Affect Plant Productivity

By Guest PostNovember 3, 2012Environmentamazonia, biogeochemical cycles, boreal, boreal forest, carbon cycle, carbon dioxide, data, earth, ecosystem, eleanor blyth, eurasian forest, fertile earth, fertilization, global, grasslands, grayson badgley, greenhouse gas, growth, hawaii, jet propulsion, josh fisher, laboratory, level, maps, migration, model, NASA, nitrogen, North America, north american, nutrient, ozone mapping, palo alto, pasadena, phosphorus, plant, satellite, savannas, shrublands, soil, spectrometer, stanford university, terra spacecraft, terrestrial biosphere, total, trees, tropical forest, validation site, vegetation, vegetation productivity

PASADENA, Calif. – A new analysis led by NASA’s Jet Propulsion Laboratory, Pasadena, Calif., has estimated how much the growth of plants worldwide is limited by the amount of nutrients available in their soil. The maps produced from the research will be particularly useful in evaluating how much carbon dioxide Earth’s ecosystems may be able to soak up as greenhouse gas levels increase.

A research team led by JPL research scientist Josh Fisher used 19 years of data from NASA, National Oceanic and Atmospheric Administration and international satellites to assess the maximum possible growth of vegetation all over the world based upon available water and light conditions. The scientists then cross-compared that potential maximum with observed vegetation productivity as measured by satellites. This is the first time such an analysis has been conducted. (more…)

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…)

Counting Horseshoe Crabs

By Guest PostMay 17, 2012Nature, Sciencecensus, crab line, crab population, delaware bay, dover, eadoh reshef, fertilization, field research, horseshoe crab, joanna york, jonathan dinman, kayla krenitsky, marine science, megan nogan, migration, pvc pipe, st jones reserve, tammy beeson, teresa messmore, university of delaware, will goldman

Marine science majors conduct field research with horseshoe crab census

Wearing sneakers and rain boots, University of Delaware freshmen got their feet wet as marine biologists recently while counting horseshoe crabs along the Delaware Bay. The students participated in a monitoring effort to gain firsthand experience in field research with their fellow marine science majors.

“Where else can you go on a Saturday night to count horseshoe crabs?” freshman Will Goldman said. (more…)

Insect Glands May Illuminate Human Fertilization Process

By Guest PostMay 12, 2012Health, Scienceallan spradling, bee, cellular physiology, egg, fertilization, fruit fly, gene, hr39, human, insect glands, jianjun sun, lrh 1, mammals, receptor protein, reproductive glands, secretion, secretion glands, sperm

Baltimore, MD — Insect glands are responsible for producing a host of secretions that allow bees to sting and ants to lay down trails to and from their nests. New research from Carnegie scientists focuses on secretions from glands in the reproductive tract that help sperm survive and guide the sperm on the trip to fertilize an egg. The gene that controls the development of these glands in fruit flies provides important information about gland development in all insects, as well as potential clues to similar human reproductive glands. Their work is published this month in Current Biology.

When a female fruit fly receives sperm from a male fruit fly, lubricating secretions in her reproductive tract activate the sperm, store it, and guide it to fertilization. Without the aid of these secretions, sperm would not make it to the eggs. Carnegie’s Allan Spradling and Jianjun Sun demonstrated that the gene in charge of regulating the development of fruit fly secretion glands is called Hr39. It encodes a steroid receptor protein. (more…)

A Bug’s (Sex) Life: Diving Beetles Offer Clues About Sexual Selection

By Guest PostFebruary 6, 2012Nature, Sciencearizona desert, co evolution, dawn higginson, diving beetles, dytiscidae, epifluorescence image, Europe, evolution, evolutionary relationship, female, fertilization, great diving beetle, hygrotus sayi, invertebrate, kari segraves, kelly miller, larva, male, mammal, mollusk, reproductive organ, scott pitnick, sexual evolution, sexual selection, sexual trait, speciation, sperm evolution, sperm storage, spermatheca, syracuse university, thermonectus marmoratus, university of arizona

*Studies of diving beetles suggest sperm evolution may be driven by changes in female reproductive organs, challenging the paradigm of post-mating sexual selection being driven mostly by competition among sperm.*

Studying female reproductive tracts and sperm in diving beetles (Dytiscidae), researchers from the University of Arizona and Syracuse University have obtained a glimpse into a bizarre and amazing world of sperm that can take on a variety of forms – including joining together into conglomerates that navigate the twisted mazes of the female reproductive tract.

Analyses of the evolutionary relationships among diving beetles reveal that sperm form appears to follow function dictated by female reproductive organs. (more…)