Friday, March 08, 2024

Research reveals traits that make fish prey tasty to tuna

A cross-border science collaboration has yielded a global database that will help researchers understand how climate change is affecting ocean predators like the albacore tuna—which also happens to be an important food source for people around the world.

"Climate change is shifting where species can live, and the pace of change is most intense in the ocean," says Stephanie Green, associate professor in the Department of Biological Sciences and Canada Research Chair in Aquatic Global Change Ecology and Conservation

"Our big questions are where will marine species go, and what will it mean for communities that rely on the fisheries they support?"

To tackle these questions, researchers at the University of Alberta are collaborating with colleagues in the United States to discover how top predators will respond to climate extremes and changing prey over the coming decades.

Wind and currents in the Pacific Ocean make the west coast of Canada and the United States an attractive feeding ground for migrating predators like tuna, where they support lucrative fisheries and also a hotbed of climate impacts.

The team honed in on albacore tuna, a torpedo-shaped predator known to eat hundreds of different species around the world and whose harvest is regulated by a treaty between the United States and Canada.

Diverse diet—but similar traits

The buffet of prey albacore consume makes it tough for scientists to predict where their populations will go as climate change worsens. To address this challenge, the science team shone a different light on the snacking habits of this ocean predator by looking at the common characteristics or traits of the foods they eat.

"Just like we choose foods based on what we like—be it a salty pretzel or sweet, crunchy apple—ocean predators make decisions based on the characteristics of the prey they are faced with," says Green.

To figure out what traits are important to ocean predators, the researchers created a database categorizing more than 30 traits including fat and protein content, shape, color, size, and behaviors that make ocean species potentially tasty to predators, including albacore tuna.

"Our goal is to understand better when and where the most desirable prey will be found as the climate changes," says Green.

"What we're finding is that albacore tuna are quite adaptable; from among the hundreds of species they could eat, they seek out prey that have all the characteristics they prefer and focus on them," explains research associate and study lead author Miram Gleiber.

Through the use of trait-based studies, the group hopes to create a new way to understand how ocean predators are adapting to the impacts of climate change.

Big data, open for ocean discovery

Oceans cover more than 70 percent of the planet yet are less explored than space. The research team, including seven U of A students, put in more than 10,000 hours to generate 155,000 unique pieces of information on the traits of 521 species of fish, crustaceans, squids, octopuses, and more found in ocean environments.

While many species are important prey for top predators like tunas, sharks, salmon and many others in ocean systems worldwide, other animals the team documented are known only from a handful of specimens.

The trait database is also available for international scientists to support learning about how systems are changing, Green notes.

"Large datasets like this one are created to support statistical models that look at the distribution of ocean species and how interactions between ocean species, such as between predators and their prey, might look in the future."

"We're getting lots of interest from scientists elsewhere who are using the information we've gathered, which is really exciting and rewarding for us to see," says Natasha Hardy, a research associate who led the global diet synthesis.

Outlook for the oceans

The influence of climate change on ecosystems is complex, including more extreme weather events like heat waves that drastically alter marine environments. Marine heat waves are masses of superheated water, many degrees warmer than normal, that form in the ocean, disrupting the natural cycle that species in the ocean rely on for tracking their food, spawning, and migrating.

"Scientists are finding some species hundreds of miles from where we've ever seen them before, and that's likely wreaking havoc on the system," says project co-lead Larry Crowder, a professor at Stanford University's Hopkins Marine Science Center.

Some species are mobile and can adapt to changing environments, but many live close to the edge of the ranges in temperature, acidity, and other stressors they can endure, causing some species to lose entire habitats, Crowder says.

The findings are published in the journal Scientific Data.

More information: Miram R. Gleiber et al, The Pelagic Species Trait Database, an open data resource to support trait-based ocean research, Scientific Data (2024). DOI: 10.1038/s41597-023-02689-9

Provided by University of Alberta How short-term heat waves impact apex marine predators

Mapping chemical footprints in European streams

by Helmholtz Association of German Research Centres

Many pesticides, industrial chemicals, and pharmaceuticals, as well as their degradation products, end up in streams and rivers after use.

A team of environmental chemists at the UFZ has therefore taken a closer look at 610 chemicals with known occurrence patterns or problematic effects and analyzed whether and in what concentrations they occur in European watercourses—from large rivers such as the Elbe, Danube, and Rhine to the Ebro and Tagus on the Iberian Peninsula to smaller streams in agricultural regions of Germany.

After analyzing 445 samples from 22 rivers, the researchers detected 504 of the 610 chemicals. They found 229 pesticides and biocides and 175 pharmaceutical chemicals, as well as surfactants, plastic and rubber additives, per- and polyfuoroalkyl substances (PFAS), and corrosion inhibitors.

They detected up to 50 chemical substances in 40% of the samples and 51–100 chemicals in a further 41%. In four samples, they were even able to detect more than 200 organic micropollutants. They detected the most substances—241 chemicals—in a water sample taken from the Danube.

In the samples, the environmental chemists most frequently found N-acetyl-4-aminoantpyrine, which is a degradation product of the analgesic metamizole. Little is known about the effects of this substance on freshwater ecosystems.

"For many of these metabolites, it is unclear how harmful they are to the environment. We still lack the necessary knowledge," says UFZ environmental chemist Saskia Finckh, co-lead author of the study. However, the negative effects of other substances detected in the waters have already been researched

One of the most common of these substances is the anticonvulsant carbamazepine, which is not readily biodegradable in bodies of water. It also impairs the reproductive capacity of invertebrates and delays the development of fish. Carbamazepine is, therefore, already on the watch list of the Federal Environment Agency (UBA) and is one of 23 other proposed priority substances to be added to the EU Water Framework Directive.

The effect of some other substances also frequently detected in the samples is also known. For example, the UFZ researchers frequently found the insecticides diazinon and fipronil, both of which are extremely harmful to aquatic invertebrates. In total, the chronic risk thresholds for invertebrates were exceeded for more than 70 chemicals detected in the waters. This means that prolonged or repeated exposure can lead to developmental disorders, among other things.

Many of the individual organic micropollutants are a problem for water bodies in their own right. However, there is an additional one to worry about. "The range of chemicals that are discharged into water bodies is a big problem. We still know far too little about the additive effects of these substances when they mix with each other", explains Dr. Eric Carmona, UFZ environmental chemist and co-lead author.

In order to be able to assess the impact of these mixing effects on the organisms living in the watercourses, the researchers applied the concept of the chemical footprint, which quantifies the potential of chemical mixtures to affect water quality—specifically, what chance of survival in aquatic organisms such as fish, crustaceans, and algae have at a particular site. The chemical footprint is calculated by relating the concentration of a chemical at a site to the expected effect.

The values for the chemicals detected are then summed. For each of these groups of organisms, there is a scientific limit value. Exceedances of this value may support the disappearance of vulnerable species from the ecosystem. The scientific limit values were exceeded in 74% of the samples tested. The risk is particularly high for crustaceans; at 15% of the sites surveyed, it is even acute, which means that the animals have little chance of survival at these sites.

The UFZ researchers conclude that despite many improvement measures, there are still too many chemicals in European waters. At many sites, the limit values are exceeded.

"Our data also show that it is not just individual substances but rather the large number of substances that contribute to this problem," says Finckh. It is, therefore, necessary to include even more chemicals in chemical water monitoring for the implementation of the EU Water Framework Directive because these have not yet been evaluated in an environmental context. More measurement data are also needed.

"It is often completely unclear what effects chemicals have on organisms in the water and in what concentrations," says Carmona. In these cases, model-based values have been used; however, these lead to greater uncertainty than the effect values measured. "Above all, we should be focusing more on their mixtures when assessing chemicals," says Finckh.

The findings are published in the journal Environment International.

More information: Saskia Finckh et al, Mapping chemical footprints of organic micropollutants in European streams, Environment International (2023). DOI: 10.1016/j.envint.2023.108371

Provided by Helmholtz Association of German Research Centres Video: Burning 'forever chemicals' with water

The critical need to address chemical contamination in drinking water

March 04, 2024

by Colin Poitras

A Special Issue of the Journal of Exposure Science & Environmental Epidemiology co-edited by Yale School of Public Health Associate Professor Dr. Nicole Deziel, PhD, presents the latest research on exposure, health, and justice issues surrounding chemical contamination in drinking water. This Special Issue includes 17 articles authored by experts from around the globe and across multiple disciplines including environmental engineering, hydrology, exposure science, epidemiology, toxicology, and climate science. Many of the papers emerged from an international symposium organized by Dr. Deziel and Associate Research Professor Dr. Cristina Villanueva, PhD, a drinking water expert with ISGlobal, and co-editor of the Special Issue. The symposium was held in Barcelona and virtually in September 2022 while Dr. Deziel was in residence on sabbatical. Dr. Deziel discussed the focus of the Special Issue in a recent online interview.

What are the specific concerns regarding human exposure to chemical contaminants in drinking water?

Populations worldwide are exposed to a myriad of chemicals via drinking water, yet only a handful of chemicals have been thoroughly evaluated with regard to human exposures and health. Furthermore, there are only federal drinking water standards for approximately 100 different chemicals. Some of the existing standards have not been updated for quite some time and there is concern that exposures to chemicals at concentrations below current standards could still be associated with an increased risk of health effects, such as birth defects and cancers. In addition, there are many emerging chemicals in drinking water (e.g., microplastics, 1,4-dioxane) that are unregulated. Lastly, we must consider the issue of water scarcity and climate change. As the world’s temperature rises, we are already seeing available public water supplies starting to dry up, resulting in an increase in desalination efforts in some areas and the use of treated wastewater in others to meet demand. Overall, we have limited knowledge of how climate events will affect the quality of drinking water, and the need for more research is discussed in the Special Issue.

We need coordinated efforts to generate new health data for emerging contaminants.
Dr. Nicole Deziel, PhD

How is science responding to these concerns?

This Special Issue showcases some of the innovative new research and technologies scientists have come up with to improve chemical surveillance in drinking water and better evaluate the possible health effects attributable to contamination. This includes better methods for monitoring and evaluating water supplies, improved biological assays, and novel methods for detecting harmful particulates in drinking water. We expect that these new studies will help inform regulations, encourage development of new methods and tools for assessing exposure to drinking water contaminants, and identify important issues pertaining to equity and environmental justice.

What are some of the challenges and opportunities in conducting research in this important area of public health?

Many chemicals are generally “invisible” in that they do not alter the color or odor of drinking water, and many of the associated effects are not observable for decades, making our ability to identify links between exposure and disease challenging. In addition, current tools and techniques for evaluating drinking water related exposures are limited and lag behind what is available for other environmental contaminants such as air pollution. So, there is definitely a need for additional and better data. Also, despite water contaminants often occurring in mixtures, most of the existing evaluations and related policies and regulations focus on individual chemicals without consideration of potential interactions between chemicals.

There is also an equity issue. Approximately 15% of Americans rely on domestic (private) wells for home drinking water. These are not covered by federal regulation, and the responsibility for testing or treating the well water falls on the property owner. Because private wells are not subject to regular monitoring or testing, water quality data in more rural areas are limited. Public drinking supplies also present risks. One study featured in this Special Issue found that 2.6 million people in the U.S. are relying on water systems where average fluoride concentrations exceed World Health Organization guidance limits. A separate study found that manganese in drinking water frequently exceeds U.S. guidelines, so there is lots to be concerned about, especially in regard to how these concentrations may impact vulnerable populations such as children.

As for the opportunities that lie before us, this Special Issue provides a framework for what needs to be done to address this critical public health concern. We need coordinated efforts to generate new health data for emerging contaminants. We need to strengthen drinking water standards and treatment technologies. We need to collect and disseminate more drinking water quality data, and we need to upgrade our drinking water infrastructure

Submitted by Colin Poitras on March 03, 2024

Featured in this article

Nicole Deziel, PhD, MHS
Associate Professor of Epidemiology (Environmental Health Sciences); Co-Director, Yale Center for Perinatal, Pediatric and Environmental Epidemiology (CPPEE)

Combined advanced oxidation dye-wastewater treatment plant: design and development with data-driven predictive performance modeling

Pankaj Singh Chauhan,

Kirtiman Singh,

Aditya Choudhary,

Urmila Brighu,

S. K. Singh &

Shantanu Bhattacharya

npj Clean Water volume 7, Article number: 15 (2024) Cite this article

- Article
- Open access
- Published: 08 March 2024
details

Abstract

The recalcitrant nature of the industrial dyes poses a significant challenge to existing treatment technologies due to the stringent environmental regulations. This combined with the inefficiency of a single treatment method has led to the implementation of the combination of primary, secondary, and tertiary treatment processes, which fails during complex secondary aeration processes due to variable pH loads of industrial effluent wastewater. This article presents a modified design methodology of a pilot-scale micro-pre-treatment unit using a solar-triggered advanced oxidation process reactor that both effectively controls the influent variability at the source and mitigates textile effluents for making the discharge reusable for different industrial purposes. The proposed modified combination technique of controlled serial processes inclusive of primary, secondary, and tertiary treatment steps with ZnO/ZnO-GO NanoMat-based advanced oxidation process demonstrates complete remediation of industrial grade effluent with effective reuse of the discharge. Further, a reliable prediction model for estimating water quality parameter using machine learning models are proposed. Multi-linear regression and Artificial Neural network modeling provide simple, accurate, and robust prediction capabilities, which are evaluated for the efficiency of the processes. The generated prediction models capture the output parameters within an acceptable level of accuracy $(R_{a d j}^{2} > 0.90)$ and allow compliance with the discharge Inland Water Discharge Standards (IWDS).

READ ON/DOWNLOAD PDF

How aromatic dissolved organic matter affects organic micropollutant adsorption

by Eurasia Academic Publishing Group

Activated carbon is employed for the adsorption of organic micropollutants (OMPs) from water, typically present in concentrations ranging from ng L−1 to μg L−1. However, the efficacy of OMP removal deteriorates considerably due to competitive adsorption from background dissolved organic matter (DOM), present at substantially higher concentrations in mg L−1. Interpreting the characteristics of competitive DOM is crucial in predicting OMP adsorption efficiencies across diverse natural waters.

In a study published in Environmental Science and Ecotechnology, a multi-national team describes the intricate influence of aromaticity and polarity in low MW DOM competition, from a fraction level to a compound level. They achieved this by employing direct sample injection liquid chromatography coupled with ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry.

Anion exchange resin pre-treatment eliminated 93% of UV254-active DOM, predominantly aromatic and polar DOM, and only minimally alleviated DOM competition. Molecular characterization revealed that nonpolar molecular formulas (constituting 26% PAC-adsorbable DOM) with medium aromaticity contributed more to the DOM competitiveness.

Isomer-level analysis indicated that the competitiveness of highly aromatic LMW DOM compounds was strongly counterbalanced by the increased polarity. These findings suggest that aromatic DOM (as measured by UV254) was not essentially competitive against OMPs in adsorption.

The study illustrates the counterbalancing effect of aromaticity and polarity in understanding the competitive adsorption of DOM and highlights the limitations of relying solely on aromaticity or UV254-based methods as the sole interpretive metric.

More information: Qi Wang et al, How aromatic dissolved organic matter differs in competitiveness against organic micropollutant adsorption, Environmental Science and Ecotechnology (2024). DOI: 10.1016/j.ese.2024.100392

Provided by Eurasia Academic Publishing GroupA demonstration of substituent effects in anti-aromatic compounds

A small earthquake and 'Moodus Noises' are nothing new for one Connecticut town

Moodus in local Algonquian dialect, once spoken in area, means 'place of bad noises'

Associated Press
Published March 7, 2024

EAST HAMPTON, Conn. (AP) — Donna Lindstrom was lying in bed and looking at her phone Wednesday morning when she heard a loud bang that rattled her 19th-century house in the central Connecticut town of East Hampton.

Soon, the 66-year-old retired delivery driver and dozens of other town residents were on social media, discussing the latest occurrence of strange explosive sounds and rumblings known for hundreds of years as the "Moodus Noises."

"It was like a sonic boom," Lindstrom said. "It was a real short jolt and loud. It felt deep, deep, deep."

It was indeed a tiny earthquake with a magnitude of 1.7, according to the U.S. Geological Survey.

An area of central Connecticut has long been plagued by earthquakes. (Fox News)

Robert Thorson, an earth sciences professor at the University of Connecticut, said booms, rumblings and rattling have been recorded in the East Hampton area, including the nearby village of Moodus, for centuries, dating back well before a larger earthquake, recorded on May 16, 1791, knocked down stone walls and chimneys.

In fact, Moodus is short for "Machimoodus" or "Mackimoodus," which means "place of bad noises" in the Algonquian dialects once spoken in the area. A local high school has even nicknamed their teams "The Noises," in honor of that history.

The occurrences were frequent enough that the federal government, worried about the possible effect of seismic activity on the nearby, now-decommissioned Haddam Neck Nuclear Power Plant, conducted a study of the "Moodus Noises" in the late 1980s, Thorson said.

What they found was that the noises were the result of small but unusually shallow seismic displacements within an unusually strong and brittle crust, where the sound is amplified by rock fractures and topography, he said.

"There is something about Moodus that is tectonic that is creating these noises there," Thorson said. "And then there is something acoustic that is amplifying or modifying the noises and we don’t really have a good answer for the cause of either."

Thorson said there could be a series of underground fractures or hollows in the area that help amplify the sounds made by pressure on the crust.

"That’s going to create crunching noises," he said. "You know what this is like when you hear ice cubes break."

It doesn’t mean the area is in danger of a big quake, he said.

"Rift faults that we used to have here (millions of years ago) are gone," he said. "We replaced that with a compressional stress."

That stress, he said, has led to the crunching and occasional bangs and small quakes associated with the "Moodus Noises."

"It’s just something we all have to live with," said Lindstrom. "I’m just glad I don’t live in California."

ICYMI GOOD NEWS KIDZ
End of nuclear secrecy? Underground tests now '99% detectable'

The 1954 Castle Bravo mushroom cloud, which was one of the most environmentally damaging nuclear tests ever carried out. It was a main contributor to the banning of all surface nuclear tests in 1963.

Secret underground nuclear tests could now be a thing of the past thanks to a major scientific breakthrough in ways to identify them.

A team of Earth scientists and statisticians say they can now tell with 99 per cent accuracy if such an explosion has taken place. This is up from 82 per cent and is based on a dataset of known tests in the US, according to the new study published in Geophysical Journal International.

It has previously been tricky to differentiate between nuclear explosions and other seismic sources, such as naturally-occurring earthquakes or man-made noise above ground.

“The explosion goes off and you have all this energy that radiates out, which can be measured on seismometers,” said lead author Dr Mark Hoggard, of The Australian National University (ANU).

“So, the science problem becomes how do we tell the difference between that and a naturally-occurring earthquake?”

This was an issue seven years ago, when several of the existing methods used to identify underground nuclear explosions failed to establish that North Korea had carried out such a test.

The secretive communist state later confirmed it had successfully tested a weapon with a force of between 100-370 kilotons. For comparison, a 100 kiloton bomb is six times more powerful than the one the US dropped on Hiroshima in 1945.

North Korea is the only country known to have carried out an underground nuclear test in the 21st century, but satellite imagery revealed last year that Russia, the US and China have all built new facilities at their nuclear test sites in recent years.

Although there is no suggestion the three superpowers are planning to resume such experiments, the war in Ukraine has made the global security landscape uncertain.

“By using some revised mathematics and more advanced statistical treatment, we have managed to improve the classification success rate from 82 per cent to 99 per cent for a series of 140 known explosions in the US,” Dr Hoggard said.

“Nuclear testing in the US has largely been carried out in Nevada – in the desert – and there is a thorough seismic record of all those tests, so it provides a really helpful dataset.

“Our new method also successfully identifies all six of the tests conducted in North Korea from 2006 to 2017.”

This diagram shows 140 explosions and 1,149 earthquakes analysed by researchers. It reveals the explosions previously misidentified as earthquakes (red diamonds) and earthquakes wrongly classified as nuclear blasts (green diamonds).

ANU
Licence type
Attribution (CC BY 4.0)

Dr Hoggard said there may still be instances of underground nuclear tests being carried out surreptitiously in some parts of the world, and the sheer volume of earthquakes makes it difficult to investigate each event to determine if it is suspicious or not.

“This makes effective methods like ours all the more important,” he added.

“It also doesn’t require any new kit - you don’t have to put up satellites or anything like that, we’re just using standard seismic data.”

Dr Hoggard described the model as “pretty fast”, making it “more or less suitable for real-time monitoring”.

The research was carried out by a team of Earth scientists and statisticians working at ANU and the Los Alamos government research lab in the US.

They say the new approach “provides a means to rapidly assess the likelihood of an event being an explosion”.

The mathematical model was built by analysing the physical differences in the pattern of rock deformation at the source of nuclear explosions and earthquakes, allowing experts to determine which seismic event a recorded noise is more likely to belong to.

International efforts shifted to monitoring significant seismic waves in the aftermath of the Cuban Missile Crisis and Partial Nuclear Test Ban Treaty in the 1960s, which limited the testing of nuclear weapons to underground only.

The agreement was introduced following years of environmentally-damaging experiments carried out at the surface and/or underwater. These polluted many locations and in some instances led to catastrophic levels of radioactive fallout.

But the new monitoring it required brought about its challenges - primarily how to differentiate between nuclear explosions and other seismic sources.

It has taken more than six decades, but the scientists behind the new research believe their innovative method could now make this a lot easier for groups such as the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), which is tasked with international surveillance of nuclear testing.

Dr Hoggard said his team’s mathematical model would be “another tool in CTBTO’s armoury for detecting any potential underground tests that are conducted in secret”.

He added: “A ban on all future tests is unlikely given that several major nations remain unwilling to ratify the Comprehensive Nuclear-Test-Ban Treaty.

“Well-supported monitoring programs are therefore critical for ensuring that all governments are held accountable for the environmental and societal impacts of nuclear weapons testing.”

The paper ‘Seismic moment tensor classification using elliptical distribution functions on the hypersphere’ has been published today in Geophysical Journal International.

SPAGYRIC HERBALISM

Blighia sapida: A tropical fruit with antimicrobial properties

by American Society for Microbiology

Antimicrobial resistance (AMR) remains 1 of the top 3 global public health challenges facing humanity. Every year, 70,000 people die globally from AMR, and the threat is exacerbated by the fact that we have moved from the era of excess antibiotics to one where only a few antibiotics are considered innovative by World Health Organization (WHO) standards.

The African continent has the highest rate of AMR-related mortality, with Sub-Saharan Africa having the highest mortality rate of 23.5 deaths per 100,000 people in 2019. This is, in part, a result of poverty and fewer regulations on antibiotic use, thereby putting a limit on the solutions that can be offered.

When it comes to identifying new antimicrobials to combat AMR effectively, much can be learned from ethnobotany, an approach that has been used in developing countries for decades, which looks at the practical and medicinal uses of indigenous plants.

Blighia sapida is one plant that shows excellent antimicrobial activity and compares favorably with standard antibiotics, like streptomycin. It is ubiquitous in Africa, easily accessible and offers cost-effective extracts that can be used in the formulation of antimicrobials. Here we take a closer look at what is known about B. sapida's phytochemicals, highlight key areas for further research and introduce a few other plants that have shown activity against pathogens.

B. sapida in traditional medicine

Africa has about 5,000 species of plants that are used for medicine, some of which are antimicrobials. One of these plants is B. sapida, a plant that is ubiquitous in West Africa and can be easily cultivated at low cost. Called by many names in different parts of the continent (Okpu, Isin, Isin, akee apple, etc.), B. sapida is a gem that is used in many industries, including construction. However, its use in medicine in these developing countries is distinct.

The plant extracts have demonstrated in vitro and in vivo antidiarrheal, anticancer, hypoglycemic and antioxidant activities. B. sapida has been used to treat oedema, dysentery and diarrhea, fever, ulcers, yaws, intercostal pain, epilepsy and yellow fever. It has also demonstrated effectiveness in treating gonorrhea, psychosis, stomach ache, rheumatism, hernia, constipation and even cancer. Unripened B. sapida is poisonous for consumption, as it contains a high concentration of hypoglycin A. However, the arils (an additional outgrowth that covers, or partially covers, B. sapida seeds) lose toxicity as the fruit ripens, making the arils of mature ackee safe for consumption.

B. sapida also has antimicrobial properties. For example, the leaf extract of B. sapida showed in vivo antiplasmodial activity—reducing the development of Plasmodium berghei, which causes malaria in rodents. Furthermore, methanolic extract of arils of the plant inhibited in vitro growth of Klebsiella pneumoniae and Staphylococcus aureus.

In another study, B. sapida extract exhibited varying degrees of in vitro activity against S. aureus, Bacillus subtilis, Salmonella Typhi and Streptococcus pneumoniae, as well as 2 strains of gram-negative bacteria, Escherichia coli and K. pneumoniae. Notably, the stem bark and leaf extract of the plant compare favorably well with streptomycin and have low minimum inhibitory concentration and minimum bactericidal concentration in most cases. These studies provide evidence that B. sapida could serve as a drug to treat infections caused by any of these pathogens. But what exactly makes the plant active against these pathogens.

Why B. sapida works

Medicinal plants are the most common traditional medicine used in Africa because of their ease of accessibility, as well as the traditional healer's understanding of the patient's immediate environment. The tropical and subtropical climate in Africa can be hostile and facilitate adaptation of secondary metabolites, which turn out to be beneficial to human health and accumulate more chemopreventive substances than plants in the northern hemisphere.

Studies have shown that extracts from plants could have various inhibitory effects on bacteria, fungi, viruses, protozoa and even parasites due to a synergistic effect of their active ingredients. Ackee's many phytochemicals, including saponins, tannins, flavonoids and alkaloids, have antimicrobial properties and seem to be the reason for the plant's medicinal effectiveness.

For example, saponins cause lysis of bacterial cells; tannins interfere with the metabolism of the cell, eventually causing destruction; flavonoids inhibit nucleic acid synthesis and phenol suppresses the formation of bacterial biofilm. Alkaloids also disrupt bacterial cell membranes, affect DNA function and inhibit protein synthesis.

This synergy is especially important because, while bacteria could easily develop resistance to a particular mechanism of action, the fact that these plants resist microbes using the combined effect of multiple bioactive compounds ultimately reduces the possibility of resistance.

Future outlook of B. sapida

Given the many applications of B. sapida for treating various diseases, and its activity against many human pathogens, several researchers advise further studies. In order to verify that B. sapida is a viable and safe product for use in the formulation of new antibiotics against human pathogens, scientists must assess the toxicity of B. sapida to determine potential side effects, safe dosage, toxic threshold and risk for comprehensive regulatory compliance.

Researchers must also characterize the chemical composition of B. sapida using complex analyses to identify the bioactive components. There is an inadequacy in the characterization of the chemical composition of medicinal plants in Nigeria; only a few of the plants' bioactive components have been analyzed using complex analyses like high-performance liquid chromatography (HPLC).

The few existing studies on B. sapida show great prospect, but additional funding is needed to understand the underlying synergy of phytochemicals present in this medicinal plant (as well as others). Such chemical characterizations are needed to validate the medicinal claims associated with B. sapida.

Provided by American Society for Microbiology Scientists develop green method for producing bactericidal copper oxide nanoparticles from noni plant

LA REVUE GAUCHE - Left Comment