New species of giant salamander is world’s biggest amphibian

Using DNA from museum specimens collected in the early 20th century, researchers from ZSL (Zoological Society of London) and London’s Natural History Museum identified two new species of giant salamander — one of which they suspect is the world’s biggest amphibian.

Chinese giant salamanders, now classified as Critically Endangered, were once widespread throughout central, southern and eastern China. They have previously been considered a single species (Andrias davidianus). However, new analysis of 17 historical museum specimens and tissue samples from wild salamanders challenges this assumption.

The paper, published today (17.09.2019) in the journal Ecology and Evolution, found three distinct genetic lineages in salamanders from different river systems and mountain ranges across China. These lineages are sufficiently genetically different that they represent separate species: Andrias davidianus, Andrias sligoi, and a third species which has yet to be named.

One of the newly identified species, the South China giant salamander (Andrias sligoi), was first proposed in the 1920s based on an unusual salamander from southern China that lived at the time at London Zoo. The idea was then abandoned but has been confirmed by today’s study. The team used the same animal, now preserved as a specimen in the Natural History Museum after living for 20 years at the Zoo, to define the characteristics of the new species.

The other unnamed new species, from Huangshan (the Yellow Mountains), is still only known from tissue samples and has yet to be formally described.

The study’s lead author, Professor Samuel Turvey of ZSL’s Institute of Zoology, said: “Our analysis reveals that Chinese giant salamander species diverged between 3.1 and 2.4 million years ago. These dates correspond to a period of mountain formation in China as the Tibetan Plateau rose rapidly, which could have isolated giant salamander populations and led to the evolution of distinct species in different landscapes.

The decline in wild Chinese giant salamander numbers has been catastrophic, mainly due to recent overexploitation for food. We hope that this new understanding of their species diversity has arrived in time to support their successful conservation, but urgent measures are required to protect any viable giant salamander populations that might remain.

Salamanders are currently moved widely around China, for conservation translocation and to stock farms that cater for China’s luxury food market. Conservation plans must now be updated to recognise the existence of multiple giant salamander species, and movement of these animals should be prohibited to reduce the risk of disease transfer, competition, and genetic hybridisation.”

Chinese giant salamanders are the world’s biggest amphibians. The authors suggest that the newly discovered South China giant salamander — which can reach nearly two metres — is the largest of the three and is therefore the largest of the 8,000 or so amphibian species alive today.

ZSL works in China to protect giant salamanders in the wild and to raise their profile through our exhibit at London Zoo, where zookeepers welcomed four juveniles in September 2016. The salamanders were seized by Border Force after an attempt to illegally import them. One of the salamanders, named Professor Lew, has since moved into a state-of-the-art tank in the Zoo’s Reptile House, where visitors can come face-to-face with one of nature’s giants. The three others are currently being cared for behind the scenes. Keepers will eventually introduce another animal to Professor Lew as a mate and the remaining two may then move to a different zoo, as the adults are highly territorial and need to be housed in separate enclosures.

Melissa Marr, PHD researcher at the Natural History Museum London added: “These findings come at a time where urgent interventions are required to save Chinese giant salamanders in the wild. Our results indicate that tailored conservation measures should be put in place that preserve the genetic integrity of each distinct species. Our research also highlights the central role that The Natural History Museum’s collections can play in the conservation of Critically Endangered species.”

Story Source:

Materials provided by Zoological Society of London. Note: Content may be edited for style and length.

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Health24.com | Here’s another warning on soft drinks – and it doesn’t matter if they contain sugar or not, according to a large study

Whether you call it soda, pop or a soft drink, a new study’s findings suggest it would be better for your health to drink water instead.

The large European study found that people who have more than two sodas a day – with or without sugar – had a higher risk of dying over about 16 years than people who sipped the fizzy beverages less than once a month.

Replace soda with water

“We found that higher soft drink intake was associated with a greater risk of death from any cause regardless of whether sugar-sweetened or artificially sweetened drinks were consumed,” said study senior author Neil Murphy. He’s a scientist with the International Agency for Research on Cancer in Lyon, France.

“Our results for sugar-sweetened soft drinks provide further support to limit consumption and to replace them with healthier beverages, preferably water,” Murphy said.

How might sodas raise your risk of dying?

Sugar-sweetened beverages may lead to weight gain and obesity. They also may affect the way the hormone insulin is used in the body, which can lead to inflammation, Murphy noted. All of these things can lead to health conditions that may shorten life.

He said more research is needed to understand how artificially sweetened soda might increase the risk of early death.

While it found an association, the current study does not prove a cause-and-effect relationship between soda and a higher risk of early death. It’s possible that soda drinkers have other habits that could add to their odds, such as smoking or a less healthy diet.

Higher risk of dying

This study isn’t the first to find a connection between soda and bad health outcomes. Two recent studies – one from BMJ and the other in Circulation – linked drinking soda to cancer and deaths from heart disease.

The current research included more than 451 000 people from 10 European countries. Their average age was 51. Researchers followed the participants’ health for an average of 16 years.

In addition to a higher risk of dying from all causes for those who drank more than two sodas a day, more sodas were also linked to some specific causes of death.

  • People who had more than one soda daily – sugar-sweetened or artificially sweetened – compared to fewer than one a month had a higher risk of dying from colon cancer and Parkinson’s disease.
  • People who had more than one sugar-sweetened soda a day compared to fewer than one a month had a higher risk of dying from digestive diseases.
  • People who had more than one artificially sweetened soda a day compared to less than one a month had a higher risk of dying from circulatory diseases like heart disease.

Murphy said researchers tried to account for factors such as body mass index (an estimate of body fat based on height and weight) and smoking, and still found an association between drinking more soda and a higher risk of dying.

Representatives of the beverage and sweetener industries urged people not to overreact to the findings.

Excess consumption of soft drinks

Low-calorie and no-calorie sweeteners are “an important tool for weight management and those managing diabetes,” said Robert Rankin, president of the Calorie Control Council.

The council’s medical adviser, Dr Keri Peterson, added: “The safety of low- and no-calorie sweeteners has been reaffirmed time and time again by leading regulatory and governmental agencies around the world.”

William Dermody Jr., a spokesman for the American Beverage Association, offered a similar view. “Soft drinks are safe to consume as part of a balanced diet and the authors of this study acknowledge their research does not indicate otherwise.”

But Dr Maria Anton, an endocrinologist at Northwell Health’s Long Island Jewish Forest Hills Hospital, said excess consumption of soft drinks and other high-sugar and artificially sweetened beverages has become the norm for many people.

“These can contribute to weight gain and poor blood sugar control, worsening existing conditions like diabetes,” she pointed out.

Fuelled by marketing and advertising

Anton added that the findings suggest sugar is probably not the only unhealthy ingredient in soft drinks. “Patients in this study who regularly consumed sugar-free, artificially sweetened drinks were also at an increased risk of death,” she pointed out.

Registered dietitian Samantha Heller, from NYU Langone Health in New York City, said many factors may contribute to the link between soda consumption and risk of death. The bottom line, she said, is that people don’t need to drink soda.

“The consumption of beverages that taste sweet is fuelled by marketing and advertising. There really is no need to consume them,” Heller said, suggesting suggested water, seltzer or tea instead.

The study was published in JAMA Internal Medicine.

Image credit: iStock

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Health24.com | WATCH: Researchers discover routine to overcome insomnia

Stringr

Long-term effects of sleep deprivation can lead to serious health issues, including hypertension and depression. However, a new study conducted by the UT Health Science Center at Houston and the University of Southern California, found a simple but unusual routine that can help many overcome insomnia.

Image: iStock

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Health24.com | Do you really need to give up carbs to lose weight?

If you’ve been in the diet circle for a while, you know that the number one weight loss rule has always been this: Cut carbs. In the Nineties, the Atkins diet was all the rage – now we’ve got Keto. Both of these popular diets preach low-carb, the apparent weight-loss key. But are there harmful side-effects of switching your side of chips for a tiny garden salad? And are carbs really the waist-expanding enemy we’ve been led to believe they are?

Wait, carbs aren’t a food group?

“Carbs are not a food group on their own. They are a specific type of nutrient found, together with many others, in certain food groups,” says registered dietician Tirsa B Holzhausen, a spokesperson for the Association for Dietetics in South Africa.

There are also many different types of carbs. Think: Glucose; fructose (fruit sugar); lactose (found in dairy); sucrose (table sugar) and amylose or amylopectin (generally known as starch). Another little known, but beneficial, carb is fibre.

READ MORE: These ‘Healthy Carbs’ Can Help You Lose Weight

Carbohydrates perform five important functions in the body:

1. They’re a source of energy

The glucose found in carbohydrate-containing foods is used by the body’s cells (especially the cells in the brain) to create energy molecules (known as ATP). These molecules act as fuel for activities in the body. The body can produce ATP from other sources, including fats (the reasoning behind the Keto diet), but glucose is the body’s preferred fuel.

2. They provide energy to store

When a meal provides more glucose than the body needs immediately to make energy, the excess glucose is converted to glycogen (stored in the liver and muscles). When the glycogen stores are full, the remaining glucose is converted into fat molecules.

Glycogen is essential for healthy functioning because it can quickly be converted back into glucose in situations when the body needs the energy, typically during exercise or starvation (voluntary or not). But when we continuously eat more carbs than the body needs, we end up with excess carbs, which are converted to fat. Bottom line: The body needs some carbs for energy and storage, but too many lead to a fight with the flab.

READ MORE: 16 Carbs To Avoid If You’re Trying To Prevent A Sugar Crash

3. They save muscle protein

When there’s too little glucose available in the bloodstream, the body makes glucose from glycogen, but when the glycogen stores are depleted, the body breaks down protein in the muscles to create the needed glucose. Over an extended period, this can be dangerous and typically leads to poor strength, poor immunity and a general decline in overall health.

4. They play an important role in digestive health

While most starches are broken up into glucose (among other things) during digestion, fibre isn’t. The process of digesting fibre provides energy for the ‘good’ bacteria in the gut, which allows them to work optimally in digesting other nutrients. Soluble fibre (found in fruits, veggies and oats) causes water to be drawn into the intestine as they digest, creating a soft stool that’s easy to pass. Insoluble fibre (found in legumes, whole grains, nuts and seeds) provide roughage in the intestine, which stimulates movement and helps to keep us ‘regular.’

READ MORE: How Many Carbs Should I Eat If I’m Trying To Lose Weight?

5. It’s important for heart health and blood sugar control

Depending on the type of carbohydrate-containing food, carbs can either benefit your heart health or seriously diminish it. During digestion, fibre binds to bile acids in the intestine and passes through the body; this loss of bile acids stimulates the body to make more, a process which uses cholesterol from the bloodstream.

This cycle lowers cholesterol in the blood, and over a longer period contributes to healthy blood pressure and cholesterol levels, healthy blood vessels, effective functioning of the heart muscle and prevention of atherosclerosis and other heart-related conditions. Eating refined, high sugar carbs will have the opposite effect…

Fibre also slows down the rate at which foods are digested, meaning that all nutrients, including glucose, enter the bloodstream at a slower, more controlled rate and in smaller amounts at a time. This process prevents blood sugar spikes and the fatigued feeling that follows a sugar high. It also provides better insulin-level control and more stable energy levels.

Side effects of cutting out carbs:

Most low-carb diets focus on cutting refined carbs like white bread and pasta, along with sugar and low-fat dairy options. If your body is used to eating these kinds of foods, your body might go through ‘withdrawal symptoms’, which include:

  • Low blood sugar symptoms: This can range from feeling light-headed and shaky to experiencing headaches or undergoing mood changes.
  • Loss of body protein: This depends on how severely, and for how long, carbs are restricted (zero-carb diets will be a risk factor). Poor health and body function could result from long-term protein breakdown in the body.
  • Ketosis: This is the state in which the body burns fat for fuel, which may sound exciting, but over a long period of time it is detrimental to the brain and can lead to mental and physical fatigue, as well as bad breath in the short term.
  • Micronutrient shortages: Loss of nutrients such as fibre, vitamin B2, folate, potassium, calcium, magnesium and protein. Lack of minerals could cause muscle cramps in the short term and negatively affect heart health in the long term; lack of fibre could result in constipation and lack of B-vitamins could diminish the body’s energy metabolism, red blood cell production and nerve function.
  • Digestive issues: Low-carb usually means high protein or fat intakes. These types of foods could cause diarrhoea or general gastric discomfort if they’re too rich or challenging for the intestine to tolerate. Plus, lack of fibre impairs the intestine’s ability to function optimally, which could worsen the symptoms you’re already experiencing.
  • READ MORE: 15 Complex Carbs You Should Def Incorporate Into Your Diet

    How can you include carbs in your diet but still lose weight?

    According to Tirsa, including carbs in your diet doesn’t mean eating refined carbs like processed snacks or high-sugar foods like fruit juice. Healthier carbs include:

    • Wholegrain starches: Brown rice, quinoa, barley and oats.
    • Unrefined foods: Fresh fruit, milk, porridge, rice, potato, sweet potato, dry or tinned peas and beans and popcorn.
    • Minimally pre-prepared foods: It’s difficult in our modern-day to avoid all processed foods, but take-away, ready-to-eat and heat-and-eat foods (pasta, pizza, smoothie, freshly-squeezed juice, salad or sandwiches) all usually have a higher sugar content than the version you’d make at home. They’re also usually more processed and served in a bigger portion than your homemade version. By preparing your own meals, you can choose better-quality ingredients and will have more control over the quantities of each ingredient used.

    So make “carbs” a small part of a bigger meal…

    A large portion of carbs (a big bowl of pasta, three-slice sandwich or burger and chips) will provide way more carbs than your body needs. To avoid eating too many or too few carbs, prepare meals which consist of 25% starch (brown rice, quinoa, barley, sweet potato, porridge or bread); 25% protein (animal or plant-based) and 50% vegetables, which could also include a fruit portion.

    Practically, this could look like:

    Breakfast: Oats with low-sugar yoghurt and berries or scrambled egg with one slice whole-wheat toast and avocado salsa.

    Lunch: Roasted sweet potato and chicken salad with homemade salad dressing or a chicken mayonnaise sandwich with a small side salad and small fruit.

    Supper: Grilled fish with savoury brown rice and roasted veg or grilled steak with roasted potato wedges and stir-fried vegetables.

    READ MORE: These 3 Pasta Substitutes Are Life-Savers If You’re Avoiding Carbs

    The bottom line

    Carbohydrates are essential nutrients which can, and should, form part of any person’s balanced, healthy diet. The question is not whether carbs are good, but rather which types and how much is needed in your individual diet. Visit a registered dietitian in your area for more info about how to include carbs in your diet in a way that will benefit your waistline as well as your long-term health.

    This article was originally published on www.womenshealthsa.co.za

    Image credit: iStock

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Antibiotic resistance surges in dolphins, mirroring humans

Antibiotic resistance is one of the biggest public health challenges in the world today since many common bacterial infections are developing resistance to the drugs once used to treat them, and new antibiotics aren’t being developed fast enough to combat the problem.

Once primarily confined to health care settings, these resistant strains of bacteria are now commonly found in other places, especially marine environments. To date, few studies have looked at long-term trends in antibiotic resistance in pathogens isolated from wildlife populations.

Researchers from Florida Atlantic University’s Harbor Branch Oceanographic Institute in collaboration with Georgia Aquarium , the Medical University of South Carolina and Colorado State University, conducted a unique, long-term study (2003 to 2015) of antibiotic resistance among pathogens isolated from bottlenose dolphins (Tursiops truncatus) in Florida’s Indian River Lagoon. This lagoon has a large coastal human population and significant environmental impacts.

“In 2009, we reported a high prevalence of antibiotic resistance in wild dolphins, which was unexpected,” said Adam M. Schaefer, MPH, lead author and an epidemiologist at FAU’s Harbor Branch. “Since then, we have been tracking changes over time and have found a significant increase in antibiotic resistance in isolates from these animals. This trend mirrors reports from human health care settings. Based on our findings, it is likely that these isolates from dolphins originated from a source where antibiotics are regularly used, potentially entering the marine environment through human activities or discharges from terrestrial sources.”

Using 13-years of data and the Multiple Antibiotic Resistance (MAR) index, researchers obtained a total of 733 pathogen isolates from 171 individual bottlenose dolphins. Several of the organisms isolated from these animals are important human pathogens.

Results of the study, published in the journal Aquatic Mammals, shows that the overall prevalence of resistance to at least one antibiotic for the 733 isolates was 88.2 percent. The prevalence of resistance was highest to erythromycin (91.6 percent), followed by ampicillin (77.3 percent) and cephalothin (61.7 percent). This is one of the few studies to use the MAR index for bacterial isolates from a marine mammal species.

Resistance to ciprofloxacin among E. coli isolates more than doubled between sampling periods, reflecting recent trends in human clinical infections. Pseudomonas aeruginosa, responsible for respiratory system infections, urinary tract infections, among others, were the highest recorded for any organism and increased during the study period.

The MAR index increased significantly between the periods 2003-2007 and 2010-2015 for P. aeruginosa and Vibrio alginolyticus, a common pathogenic marine Vibrio species found to cause serious seafood-poisoning. For all bacterial isolates, resistance to cefotaxime, ceftazidime and gentamicin increased significantly between sampling periods.

“The Health and Environmental Risk Assessment or HERA Project has helped discover that the emerging bacterial resistance to antibiotics in bottlenose dolphins is prevalent. Bottlenose dolphins are a valuable sentinel species in helping us understand how this affects human and environmental health. Through HERA we’ve been able to provide a large database of information in order to continue learning from these impressive animals,” said Gregory D. Bossart, V.M.D., Ph.D., co-author, senior vice president and chief veterinary officer at Georgia Aquarium. “Antibiotic resistance is one of the most significant risks to public health. As resistance increases, the probability of successfully treating infections caused by common pathogens decreases.”

The sampling for the study was conducted and funded in part by the Florida Specialty License Plate fund and Georgia Aquarium with Bossart serving as the HERA lead and permit holder. Swab samples for microbiology were taken from the blowhole, gastric fluid and feces and cultured on standard media under aerobic conditions. The most frequently isolated pathogens were Aeromonas hydrophila, E. coli, Edwardsiella tarda, V. alginolyticus, and S. aureus, pathogens frequently associated with aquatic environments. The dolphins were captured and released back into the Indian River Lagoon as a part of the HERA Project. Sampling took place during June and July each year.

“The nationwide human health impact of the pathogen Acinetobacter baumannii is of substantial concern as it is a significant nosocomial pathogen with increasing infection rates over the past 10 years,” said Peter McCarthy, Ph.D., co-author, a research professor and an associate director for education at FAU’s Harbor Branch. “In addition to nosocomial infections, resistant strains associated with fish and fish farming have been reported globally. The high MAR index for this bacteria isolated from dolphins in the Indian River Lagoon represents a significant public health concern.”

Each year in the United States, at least 2 million people get an antibiotic-resistant infection, and at least 23,000 people die.

Co-authors of the study are Tyler Harrington, FAU’s Harbor Branch; Patricia A. Fair, Ph.D., Medical University of South Carolina; and John S. Reif, Ph.D., Colorado State University.

This work was funded in part by the Protect Wild Dolphin License Plate funds granted through the Harbor Branch Oceanographic Institute Foundation and Georgia Aquarium.

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