Antibiotics could trigger immune response through gut microbiome metabolites

American Chemical Society

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The microbes inside our bodies not only help break down food but also impact our health. Yet their precise influence is not always understood, especially in the presence of prescription drugs. Now, researchers in ACS Central Science report how one of the most abundant gut bacteria responds to tetracyclines, a class of commonly prescribed antibiotics. Newly characterized signals released by the bacterium could aid the host’s immune response, inhibit pathogens and restructure the gut microbiome.

“We previously showed that exogenous molecules can trigger production of otherwise ‘hidden’ metabolites in marine- and soil-dwelling microbes,” says Mohammad Seyedsayamdost, the corresponding author of the study. “Our goal here was to extend this analysis to human microbiota and examine their responses to FDA-approved drugs.”

Every day, medical professionals across the country prescribe drug treatments for a variety of ailments. Although these drugs may have their desired effect, there is also the possibility that they impact the microbes that keep us healthy. Antibiotics, for example, often inactivate not only offending microbes but also beneficial gut bacteria. Scientists have proposed the idea that consuming pharmaceuticals could also alter microbial metabolism, changing the compounds that bacteria release into the body and impacting human health. To study this, Seyedsayamdost and colleagues exposed separate cultures of the prominent gut microbe Bacteroides dorei to hundreds of U.S. Food and Drug Administration (FDA)-approved drugs — such as antihistamines, hypertension drugs, anticancer agents and antibiotics — and looked for metabolic changes compared to untreated bacterial cultures.

After incubating B. dorei with and without pharmaceuticals, the researchers isolated and identified compounds the bacterium secreted. Among the various drugs tested, low doses of tetracycline antibiotics had the strongest effect on bacterial cultures, inducing the microbes to produce two types of new compounds: doreamides, named in this study, and N-acyladenosines. Further testing showed that both compounds trigger human immune cells to produce proteins called pro-inflammatory cytokines, which can help respond to infections. The doreamides also induced production of host antimicrobial peptides that inhibited the growth of several bacterial strains, including pathogenic ones, but not the growth of B. dorei.

The experiments demonstrated a secondary effect of antibiotic treatment beyond inactivating microbes directly. Low-dose tetracyclines caused B. dorei to produce compounds that stimulate the immune system and induce immune cells to generate antimicrobial peptides, which could alter the microbial balance in the human gut. These findings set the stage for animal studies to explore possible therapeutic properties of the doreamides.

The authors acknowledge funding from the Leona M. and Harry B. Helmsley Charitable Trust, the National Institutes of Health, the MacArthur Foundation, the Simons Foundation, the National Research Foundation of Korea, and the Edward C. Taylor 3rd Year Fellowship in Chemistry.

The paper’s abstract will be available on Dec. 3 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acscentsci.5c00969

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The American Chemical Society (ACS) is a nonprofit organization founded in 1876 and chartered by the U.S. Congress. ACS is committed to improving all lives through the transforming power of chemistry. Its mission is to advance scientific knowledge, empower a global community and champion scientific integrity, and its vision is a world built on science. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, e-books and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

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Journal

ACS Central Science

DOI

10.1021/acscentsci.5c00969 

Article Title

Tetracycline Antibiotics Induce Biosynthesis of Pro-inflammatory Metabolites in the Immunobiotic Bacteroides dorei

Article Publication Date

3-Dec-2025

 

A new study finds high-narcissism CEOs pursue more acquisitions in response to strong firm performance

Strategic Management Society

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Managers’ narcissistic tendencies may fundamentally affect whether a company makes risky or safe moves as a response to the firm’s above-aspiration performance, according to a new study published in Strategic Management Journal. In a study that helps to clarify prior conflicting research, the researchers find evidence that high-narcissism CEOs respond to above-aspiration performance with more acquisitions, while low-narcissism CEOs avoid acquisitions.

The study authors — Korcan Kavusan of Erasmus University, Daniel Z. Mack of Singapore Management University, Matthew P. Mount of Deakin University, and Gokhan Ertug of Singapore Management University — were motivated to determine why firms sometimes make major moves, such as acquisitions, even when their performance exceeds expectations. Existing scholarly literature was inconsistent, suggesting there was a missing piece of the puzzle.

“Some studies suggest that success discourages change because there is no need to fix what is working,” Kavusan says, “while others argue that it encourages change by providing extra resources and managerial discretion.”

But management research has also suggested that firm actions are often shaped by the personal goals of managers — and narcissism in particular is often linked to strong personal ambitions. As such, the team chose to study whether narcissistic leaders are especially inclined to pursue acquisitions, especially when firm performance is strong and they have the discretion to act.

Using data from publicly listed U.S. manufacturing firms in the S&P 1500, the researchers explored whether high-performing firms make more acquisitions when led by narcissistic CEOs and fewer when led by less narcissistic executives. In addition to data on acquisition activity, they also collected indicators of CEO narcissism established in prior research, along with firms’ performance relative to their aspirations over time. Through statistical analysis, they indeed confirmed their hypothesis that firms led by more narcissistic CEOs tend to pursue more acquisitions when performance is high, and firms led by CEOs without strong narcissistic tendencies make fewer acquisitions.

“While acquisitions are often pursued to gain new resources, expand capabilities, and accelerate growth, many fail to achieve their intended goals and instead erode shareholder value,” Kavusan says. “Our findings show that these decisions are not always guided purely by organizational motives, as they should be in an ideal world, but can also be influenced by the personal ambitions of top executives.”

For boards, investors, and managers, the study emphasizes the need to better understand the personal drivers of those advocating for an acquisition: If stakeholders can ensure that acquisition decisions are aligned with a firm’s real needs and capabilities — not just a leader’s personal ambitions — they can increase the chances that the acquisitions create value.

To read the full context of the study and its methods, access the full paper available in the Strategic Management Journal.

About the Strategic Management Society

The Strategic Management Society (SMS) is the leading global member organization fostering and supporting rigorous and practice-engaged strategic management research. SMS enjoys the support of 3,000 members, representing more than 1,100 institutions and companies in more than 70 countries. SMS publishes three leading academic journals in partnership with Wiley: Strategic Management Journal, Strategic Entrepreneurship Journal, and Global Strategy Journal. These journals publish top-quality work applicable to researchers and practitioners with complementary access for all SMS Members. The SMS Explorer offers the latest insights and takeaways from the SMS Journals for business practitioners, consultants, and academics.

Click here to subscribe to the monthly SMS Explorer newsletter.

Click here to learn more about the programs and opportunities SMS has to offer.

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Journal

Strategic Management Journal

DOI

10.1002/smj.70009 

Article Title

High flying adored: How CEO narcissism influences firms' responses to above-aspiration performance with risky organizational change

 

A new study finds high-narcissism CEOs pursue more acquisitions in response to strong firm performance

Strategic Management Society

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

Managers’ narcissistic tendencies may fundamentally affect whether a company makes risky or safe moves as a response to the firm’s above-aspiration performance, according to a new study published in Strategic Management Journal. In a study that helps to clarify prior conflicting research, the researchers find evidence that high-narcissism CEOs respond to above-aspiration performance with more acquisitions, while low-narcissism CEOs avoid acquisitions.

The study authors — Korcan Kavusan of Erasmus University, Daniel Z. Mack of Singapore Management University, Matthew P. Mount of Deakin University, and Gokhan Ertug of Singapore Management University — were motivated to determine why firms sometimes make major moves, such as acquisitions, even when their performance exceeds expectations. Existing scholarly literature was inconsistent, suggesting there was a missing piece of the puzzle.

“Some studies suggest that success discourages change because there is no need to fix what is working,” Kavusan says, “while others argue that it encourages change by providing extra resources and managerial discretion.”

But management research has also suggested that firm actions are often shaped by the personal goals of managers — and narcissism in particular is often linked to strong personal ambitions. As such, the team chose to study whether narcissistic leaders are especially inclined to pursue acquisitions, especially when firm performance is strong and they have the discretion to act.

Using data from publicly listed U.S. manufacturing firms in the S&P 1500, the researchers explored whether high-performing firms make more acquisitions when led by narcissistic CEOs and fewer when led by less narcissistic executives. In addition to data on acquisition activity, they also collected indicators of CEO narcissism established in prior research, along with firms’ performance relative to their aspirations over time. Through statistical analysis, they indeed confirmed their hypothesis that firms led by more narcissistic CEOs tend to pursue more acquisitions when performance is high, and firms led by CEOs without strong narcissistic tendencies make fewer acquisitions.

“While acquisitions are often pursued to gain new resources, expand capabilities, and accelerate growth, many fail to achieve their intended goals and instead erode shareholder value,” Kavusan says. “Our findings show that these decisions are not always guided purely by organizational motives, as they should be in an ideal world, but can also be influenced by the personal ambitions of top executives.”

For boards, investors, and managers, the study emphasizes the need to better understand the personal drivers of those advocating for an acquisition: If stakeholders can ensure that acquisition decisions are aligned with a firm’s real needs and capabilities — not just a leader’s personal ambitions — they can increase the chances that the acquisitions create value.

To read the full context of the study and its methods, access the full paper available in the Strategic Management Journal.

About the Strategic Management Society

The Strategic Management Society (SMS) is the leading global member organization fostering and supporting rigorous and practice-engaged strategic management research. SMS enjoys the support of 3,000 members, representing more than 1,100 institutions and companies in more than 70 countries. SMS publishes three leading academic journals in partnership with Wiley: Strategic Management Journal, Strategic Entrepreneurship Journal, and Global Strategy Journal. These journals publish top-quality work applicable to researchers and practitioners with complementary access for all SMS Members. The SMS Explorer offers the latest insights and takeaways from the SMS Journals for business practitioners, consultants, and academics.

Click here to subscribe to the monthly SMS Explorer newsletter.

Click here to learn more about the programs and opportunities SMS has to offer.

---

Journal

Strategic Management Journal

DOI

10.1002/smj.70009 

Article Title

High flying adored: How CEO narcissism influences firms' responses to above-aspiration performance with risky organizational change

 

During times of market volatility, investors should track insider trades

Washington State University

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PULLMAN, Wash. — In times of economic upheaval, investors can get a clearer picture of the stock market’s future performance if they tune into how corporate insiders are trading stocks in their own companies.

That’s a key finding from a new study of investor behavior during the Covid-19 pandemic from Washington State University researchers. The study, which was published in Pacific-Basin Finance Journal, examined the trading choices of insiders during the unprecedented market shocks of the Covid-19 pandemic — finding they often zigged when the market zagged.

When most investors were selling stocks during the early days of the pandemic, many corporate insiders were buying more. And when most of the market began to recover, a lot of insiders sold. And their trades turned out to provide excellent forecasts of how the market behaved over the following year.

“The insider trades actually correlated with the subsequent stock performance – when they bought, the stock performed better, and when they sold, the stock performed poorly, in a one-year period beyond the Covid period,” said lead study author George Jiang, professor and Gary P. Brinson Investment Management Chair in the Department of Finance and Management Science in the Carson College of Business.

Because legal trades by company insiders must be reported to the U.S. Securities and Exchange Commission and are publicly available on searchable databases at the SEC website and other sources such as Barchart — watching their choices during moments of market shock can help investors separate the signal from the noise, Jiang said. While insiders are prohibited from trading based on private information, they are permitted to make other trades—and their knowledge of their firms’ fundamentals and the overall market conditions give them a definite advantage.        

“Markets will be volatile once in a while, so uncertainty will come,” he said. “The results from this study will present some interesting lessons for the future – for investors and for regulators.”

Jiang’s co-authors were PhD student Xiaoli Ma and former PhD student Yun Ma.

The pandemic presented a “natural laboratory” for studying insider behavior and the effects of their information advantage, the authors said. In early 2020, as the global pandemic took hold, financial markets saw their most turbulent period in decades. The market crisis was uniquely uncertain, as countries responded to the pandemic in varying ways and supply chains were disrupted, and so it gave researchers a chance to examine how the advantages of insiders played out in unpredictable times.

“As we looked into the data, we realized there was actually way more insider trading than usual, which was surprising to us,” Jiang said.

The team found a significant increase in insider purchases occurred from late February to early April 2020, as the market sank. Over the rest of the year, there was a fourfold increase in insider sales. Regression analysis showed that insiders’ contrarian trading resulted in them buying undervalued stocks and selling overvalued ones, actions that predicted future market activity—highlighting the fact that insider trading became more informative during the pandemic and reinforcing concerns about information asymmetry between insiders and other investors.

“When there is volatility, this is the time when investors need more from insiders,” Jiang said. “For insiders, this is a case where investors pay more attention to whatever you do, so if you send signals to the market, it’s probably a good thing to improve market efficiency. For investors, paying attention to what insiders do can help them during times of unprecedented uncertainty.”

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Journal

Pacific-Basin Finance Journal

DOI

10.1016/j.pacfin.2025.102957 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Insider trading patterns during the COVID period