Tag Archives: Purple

For centuries, the Iron Age site functioned as a purple dye factory

Posted on by
Reply

Stoneware with purple dye residue found at Tel Shiqmona, Israel

Maria Bukin/Shalvi et al. , 2025, Plos One, CC-By 4.0

For centuries, modern Israeli coastal settlements have been home to industrial scale production from marine snails of purple dye, one of the most precious commodities in the ancient world.

Known as Tyrian Purple, it was particularly sought to color wool fabrics, and was highly regarded by wealthy and powerful people in Iron Age Mediterranean society. However, up until now, direct evidence of large-scale production sites has been sparse.

From 1100 BC to about 900 BC, Tel Shiqmona was a small Phoenician fishing village, producing small scale purple dyes. Later, when the Kingdom of Israel began to expand, the site said it had “transformed from a fishing village into a fortified purple dye production centre. Golan Charvy At the University of Chicago.

During archaeological research at the site, Sharvi and his colleagues discovered the remains of dye-dyed debris used to treat the material. 176 artifacts related to the production of purple dyes were collected, including 135 purple dye items.

The dye secretes mucus to protect itself and to kill prey. “The secretion is initially a slightly greenish fluid that oxidizes upon exposure to air and gradually turns purple,” says Sharvi. “However, to convert it into a real dye (something that chemically binds to textiles), it must be processed into solution through a complex series of chemical steps.”

Researchers argue that Tel Shiqmona is the only site in the world with clear evidence of the large-scale production of purple dyes in specialized facilities for a long time.

However, there is no historical record linking the site to the dye, and little is known about the actual process used to manufacture it, Shalvi says.

After the Kingdom of Israel fell around 720 BC, the scale of dye production fell until the Assyrians took over the site and increased the process again. When the Babylonians conquered the area around 600 BC, dye production at Tel Shiqmona was abandoned.

“It was most industrial sites in the Iron Age, and there was no monumental architecture or any particular beauty or elegance,” says Sharvi. “I think it’s a very smelly place, especially in modern noses, as the production process has produced a terrible smell. I imagine wool fleece dyed in various shades that are dry on the outside and inside of the building.

Purple dyes have captivated people all over the world, he says, and it has been the subject of extensive research. “The relationship with elite classes and religious rituals has grown in cultural, symbolic and economic significance, far beyond its function as mere colour.”

topic:

Source: www.newscientist.com

Purple passionflower utilized by researchers for herpes treatment

Posted on by
Reply

Viruses are infectious agents that affect all living things, including humans. A common human virus called herpes simplex virusor HSV, can cause cold sores, genital infections, fingertip and eye infections. When HSV infects the eye, it is called: HSV keratitis. This infection can cause visual impairment, blindness, and swelling of the brain.

The standard way for doctors to treat HSV infections is with an antiviral drug called . Acyclovir. However, the drug has been found to be no longer effective in treating some HSV infections. Persistent infections are called Acyclovir resistance infection. Therefore, scientists are searching for new ways to treat HSV infections.

Scientists at Nanjing University in China tested 502 natural compounds to determine if any could be used to treat HSV keratitis. The researchers took kidney cells from African green monkeys, treated them with these natural compounds, and infected them with the virus.

After two days, they examined the cells under a microscope to see how much damage each compound prevented compared to untreated infected cells. control sample. Out of all 502 compounds tested, the one that best protects cells from viral infection was found to be present in purple passionflower. The name of the compound is Harmol, And they reported that it inhibited more than 90% of HSV in kidney cells.

The scientists further investigated Harmol’s anti-HSV properties by testing whether it was toxic to host kidney cells. If Harmol is toxic to uninfected cells, it may kill the cells instead of protecting them from the virus. They tested nine concentrations of harmol on cells, ranging from 0 micromolar to 250 micromolar harmol. They found that the compound protected against viruses and did not kill host cells at a concentration of 12.5 micromolar.

They then studied how harmol affects virus replication and the production of viral proteins and particles within host cells. They found that Harmol inhibited HSV growth and reproduction, even in acyclovir-resistant infections. Scientists also reported that Harmol treatment inhibited HSV growth when added before, during, and after HSV infection. However, the sooner it is added, the more effective it is, and it is most effective when added before infection.

The scientists then tested whether Harmol worked in mice. They wanted to determine whether Harmol would be safe and effective for treating live animals with HSV keratitis, rather than cells alone. First, the scientists investigated whether Harmol solution could be safely applied to the eyes of mice. They applied Harmol to the eyes of one group of mice and saline to the eyes of a control group. They examined the mice’s body weight and cornea over a five-day period and found that Harmol had no effect on either compared to mice given saline. They suggested that this means Harmol is a safe treatment for mice with HSV keratitis.

Next, the scientists infected three groups of mice with HSV. They treated the first group with acyclovir, the second group with Harmol, but left the third group untreated. They administered Harmol eye drops daily for five days and observed the mice on the third and fifth day. They reported that Harmol-treated mice performed better than untreated mice in all the characteristics they observed. Harmol-treated mice fed HSV had less damage to the cornea, less eyelid inflammation, less weight loss, decreased corneal thickness, and central nervous density compared to untreated mice fed HSV. was high. They found that this was also true in mice infected with acyclovir-resistant HSV.

The researchers concluded that Harmol can reduce the early symptoms of HSV keratitis in mice. Therefore, they proposed that Harmol could be an antiviral agent against HSV. Because harmol and acyclovir interact differently with acyclovir-resistant HSV, scientists believe the two compounds must inhibit HSV in different ways. However, they noted that one limitation of the study was that the mice were only tested for five days after infection. They said further researchers should investigate the long-term safety and efficacy of Harmol treatment for HSV keratitis.


Post views: 237

Source: sciworthy.com

Greek Island of Aegina reveals ancient workshop where 3,600-year-old purple dye was made

Posted on by
Reply

Coloured dyes were essential commodities in the Mediterranean region during the Late Bronze Age.

Berger and his colleagues unearthed a purple dye factory at site K10 (marked in red) outside Colonna, Aegina, during the Bronze Age. Image courtesy of Berger others., doi: 10.1371/journal.pone.0304340.

of The small island of Aegina It is located in the middle of the Saronic Gulf, between Attica, the Peloponnese and the central Aegean Sea.

The island has played an important role in the cultural history of the Aegean for thousands of years.

From the Neolithic to the Byzantine period (6th millennium BC to the 10th century AD), Aegina's main settlement was located on a small, well-protected promontory on the northwest coast called Cape Colonna.

During the 2nd millennium BC, this densely built and heavily fortified settlement reached the height of its economic prosperity and culture.

Representative monuments, outstanding finds and rich tombs indicate an economically stable and complex social system integrated into inter-regional trade networks and emerging cultures in the Middle and Late Bronze Age Aegean.

in New paper In the journal PLoS OneDr. Lydia Berger from the Université Paris-Lodron de Salzburg and her colleagues describe the remains of a 16th century BC purple dye workshop at Aegina Colonna.

The existence of this workshop is inferred from three main pieces of evidence: purple pigment preserved on pottery shards believed to be remnants of dye containers, dyeing tools such as grinding stones and waste pits, and crushed shells of marine snails harvested for the pigment.

Analysis of the chemical composition of shells and pigments indicates that the workshop mainly produces Mediterranean snails. Murex striped dye (Hexagonal column trunk).

Excavations at the site also uncovered numerous burnt bones of young mammals, mainly piglets and lambs.

Archaeologists hypothesize that these may be the remains of animals that were ritually sacrificed as sacred offerings to protect the dye-producing areas. This practice is known from other cultural sites, but the exact relationship of these bones to dye production is not yet entirely clear.

The site provides valuable insight into the tools and processes of Mycenaean purple dye production.

Further investigations may reveal more information about the scale of dye production at Aegina Colonna, details of procedures at the site, and the use of this dye in regional trade.

“The discovery for the first time of a remarkably large amount of well-preserved pigment, a large amount of crushed mollusc shells and several functional installations allows detailed insights into the production of purple dye on the Greek island of Aegina around 3,600 years ago,” the researchers said.

_____

L. Burger others2024. More than just a colour: Archaeological, analytical and procedural aspects of Late Bronze Age purple dye production at Cape Colonna, Aegina. PLoS One 19(6):e0304340;doi:10.1371/journal.pone.0304340

Source: www.sci.news

Purple Bacteria: The New Dominant Species in Various Environments

Posted on by
Reply

With more than 5,500 exoplanets detected, the search for life is entering a new era. Astrobiologists from Cornell University and the University of Minnesota have used life on Earth as a guide to look beyond the lush landscape and expand our ability to detect signs of surface life on other worlds. A new study characterizes the reflectance spectra of purple sulfur and non-sulfur bacteria from different environments.

Coelho to extend the baseline for finding life in the universe other. They measured the reflectance of purple bacteria growing in different anoxic and aerobic environments. Image credit: Sci.News.

From houseplants and gardens to fields and forests, green is the color most associated with life on Earth’s surface. On Earth, conditions were favorable for the evolution of organisms that carried out photosynthesis, using the green pigment chlorophyll a to produce oxygen.

But an Earth-like planet orbiting another star could look completely different, receiving little or no visible light or oxygen and instead relying on photosynthesis, like some environments on Earth. may be covered in bacteria that use invisible infrared light to promote

Many such bacteria on Earth contain purple pigments instead of green, and in a world where they are predominantly purple, they could produce unique “light fingerprints” that can be detected by next generation ground and space telescopes. will be generated.

Ligia Fonseca Coelho, Ph.D., a postdoctoral fellow at Cornell University’s Carl Sagan Institute, said, “Purple bacteria are able to thrive under a wide range of conditions, making them one of the leading candidates for life that has the potential to dominate many different worlds.” “We have become one,” he said.

“We are building a database of signs of life so that telescopes can detect life even if they don’t look exactly like what we encounter around us every day,” said Dr. Lisa Kaltenegger, director of the Carl Sagan Institute. We need to make sure we don’t miss out,” he added. at Cornell University.

For this study, the authors collected samples of more than 20 types of purple sulfur and non-sulfur bacteria that can be found in a variety of environments, from shallow waters, beaches, and wetlands to deep-sea hydrothermal vents. collected and grown.

Bacteria, collectively known as purple bacteria, actually have a variety of colors, including yellow, orange, brown, and red, due to pigments related to the pigments that make tomatoes red and carrots orange.

They use a simpler photosynthetic system that utilizes a form of chlorophyll that absorbs infrared light and produces no oxygen, and they thrive in low-energy red or infrared light.

They were likely widespread on early Earth before the advent of plant-type photosynthesis, and may be particularly suited to planets orbiting cool red dwarfs, the most common type in the galaxy. there is.

“They are already thriving in certain areas here,” Dr. Coelho said.

“Imagine if they weren’t competing with green plants, algae, and bacteria. The red sun might give them the most favorable conditions for photosynthesis.”

After measuring the purple bacteria’s biological pigments and optical fingerprints, the researchers created a model of an Earth-like planet with varying conditions and cloud cover.

“In a variety of simulated environments, both wet and dry purple bacteria produced a dark-colored biosignature,” Dr. Coelho said.

“If purple bacteria thrive on the surface of frozen Earth, ocean worlds, snowball Earths, or modern Earth orbiting cooler stars, we have the tools to search for them. can do.”

team’s work will appear in Royal Astronomical Society Monthly Notices.

_____

Ligia Fonseca Coelho other. 2024. Purple is the new green. Spectrum of biological pigments and a purple world similar to the Earth. MNRAS 530 (2): 1363-1368; doi: 10.1093/mnras/stae601

Source: www.sci.news