تويت
Humble fly may be super bug's match
The advertising jingle has Louie the fly singing "I'm bad and mean and mighty unclean".
Being dirty is hardly surprising, given where flies hang out. But what do flies have that stops them from being overrun by infections?
This thought occurred to PhD student Joanne Clarke and her colleagues at the Department of Biological Sciences at Macquarie University, as they discussed where the next generation of antibiotics might come from.
"Most antibiotics were originally isolated from bacteria," Clarke said. "But we've pretty much exhausted these."
As Clarke and her supervisors, Professor Andrew Beattie and Associate Professor Michael Gillings, said in Australasian Science magazine: "Microbes that produce an antibiotic may not be sensitive to that particular antibiotic, otherwise they would kill themselves.
"Consequently it seems likely that for every antibiotic produced [from bacteria], there is at least one natural mechanism of resistance."
And that's the big problem. Bacteria are increasingly resistant to the present range of antibiotics, the so-called "super bugs".
The idea of looking to insects for new ones is that the bacteria which cause us so many problems won't have the genes to resist them, yet.
Insects are a likely source of antimicrobials not only because of where they live, but how they live. For example, in the close confines of a hive, one sick individual could wipe out the entire colony if there wasn't some way of controlling the spread of disease.
Clarke studied insects from "pretty yucky" environments.
"I looked at the sheep blowfly, the common housefly and the vinegar fly," she said. "I used the Queensland fruit fly as a control because it lays its eggs in fresh fruit."
Clarke tested material extracted from the flies on four microbes: candida yeast, E.coli, golden staph and a common soil bacterium, all of which are known to cause infections in humans.
Clarke found that adults from each test species of fly produced something which prevented all the different microbes from growing.
"I also looked at the different life stages of the flies," she said. "I predicted there wouldn't be much expression of antibiotics in pupae because they have a protective casing - they're not feeding and don't come into contact with other flies - and, in general, that's what I found."
The logical next step would be to isolate and identify the chemicals in the fly extract. But, as is increasingly the case in science, the path is not going to be smooth.
"Although industry very generously funded my PhD project for three years, they chose not to renew the funding," Clarke said. "Unless someone else funds the research, it stops at this point."
This story was found at: http://www.smh.com.au/articles/2003/...591671953.html
============
The new buzz on antibiotics
The surface of flies is the last place you would expect to find antibiotics, yet that is exactly where a team of Australian researchers is concentrating their efforts.
Working on the theory that flies must have remarkable antimicrobial defences to survive rotting dung, meat and fruit, the team at the Department of Biological Sciences, Macquarie University, set out to identify those antibacterial properties manifesting at different stages of a fly’s development.
"Our research is a small part of a global research effort for new antibiotics, but we are looking where we believe no-one has looked before,” said Ms Joanne Clarke, who presented the group’s findings at the Australian Society for Microbiology Conference in Melbourne this week. The project is part of her PhD thesis.
The scientists tested four different species of fly: a house fly, a sheep blowfly, a vinegar fruit fly and the control, a Queensland fruit fly which lays its eggs in fresh fruit. These larvae do not need as much antibacterial compound because they do not come into contact with as much bacteria.
Flies go through the life stages of larvae and pupae before becoming adults. In the pupae stage, the fly is encased in a protective casing and does not feed. "We predicted they would not produce many antibiotics," said Ms Clarke.
They did not. However the larvae all showed antibacterial properties (except that of the Queensland fruit fly control).
As did all the adult fly species, including the Queensland fruit fly (which at this point requires antibacterial protection because it has contact with other flies and is mobile).
Such properties were present on the fly surface in all four species, although antibacterial properties occur in the gut as well. "You find activity in both places," said Ms Clarke.
"The reason we concentrated on the surface is because it is a simpler extraction.”
The antibiotic material is extracted by drowning the flies in ethanol, then running the mixture through a filter to obtain the crude extract.
When this was placed in a solution with various bacteria including E.coli, Golden Staph, Candida (a yeast) and a common hospital pathogen, antibiotic action was observed every time.
"We are now trying to identify the specific antibacterial compounds," said Ms Clarke. Ultimately these will be chemically synthesised.
Because the compounds are not from bacteria, any genes conferring resistance to them may not be as easily transferred into pathogens. It is hoped this new form of antibiotics will have a longer effective therapeutic life.
المصادر
http://www.abc.net.au/science/news/stories/s689400.htm
http://www.smh.com.au/cgi-bin/common...591671953.html
The advertising jingle has Louie the fly singing "I'm bad and mean and mighty unclean".
Being dirty is hardly surprising, given where flies hang out. But what do flies have that stops them from being overrun by infections?
This thought occurred to PhD student Joanne Clarke and her colleagues at the Department of Biological Sciences at Macquarie University, as they discussed where the next generation of antibiotics might come from.
"Most antibiotics were originally isolated from bacteria," Clarke said. "But we've pretty much exhausted these."
As Clarke and her supervisors, Professor Andrew Beattie and Associate Professor Michael Gillings, said in Australasian Science magazine: "Microbes that produce an antibiotic may not be sensitive to that particular antibiotic, otherwise they would kill themselves.
"Consequently it seems likely that for every antibiotic produced [from bacteria], there is at least one natural mechanism of resistance."
And that's the big problem. Bacteria are increasingly resistant to the present range of antibiotics, the so-called "super bugs".
The idea of looking to insects for new ones is that the bacteria which cause us so many problems won't have the genes to resist them, yet.
Insects are a likely source of antimicrobials not only because of where they live, but how they live. For example, in the close confines of a hive, one sick individual could wipe out the entire colony if there wasn't some way of controlling the spread of disease.
Clarke studied insects from "pretty yucky" environments.
"I looked at the sheep blowfly, the common housefly and the vinegar fly," she said. "I used the Queensland fruit fly as a control because it lays its eggs in fresh fruit."
Clarke tested material extracted from the flies on four microbes: candida yeast, E.coli, golden staph and a common soil bacterium, all of which are known to cause infections in humans.
Clarke found that adults from each test species of fly produced something which prevented all the different microbes from growing.
"I also looked at the different life stages of the flies," she said. "I predicted there wouldn't be much expression of antibiotics in pupae because they have a protective casing - they're not feeding and don't come into contact with other flies - and, in general, that's what I found."
The logical next step would be to isolate and identify the chemicals in the fly extract. But, as is increasingly the case in science, the path is not going to be smooth.
"Although industry very generously funded my PhD project for three years, they chose not to renew the funding," Clarke said. "Unless someone else funds the research, it stops at this point."
This story was found at: http://www.smh.com.au/articles/2003/...591671953.html
============
The new buzz on antibiotics
The surface of flies is the last place you would expect to find antibiotics, yet that is exactly where a team of Australian researchers is concentrating their efforts.
Working on the theory that flies must have remarkable antimicrobial defences to survive rotting dung, meat and fruit, the team at the Department of Biological Sciences, Macquarie University, set out to identify those antibacterial properties manifesting at different stages of a fly’s development.
"Our research is a small part of a global research effort for new antibiotics, but we are looking where we believe no-one has looked before,” said Ms Joanne Clarke, who presented the group’s findings at the Australian Society for Microbiology Conference in Melbourne this week. The project is part of her PhD thesis.
The scientists tested four different species of fly: a house fly, a sheep blowfly, a vinegar fruit fly and the control, a Queensland fruit fly which lays its eggs in fresh fruit. These larvae do not need as much antibacterial compound because they do not come into contact with as much bacteria.
Flies go through the life stages of larvae and pupae before becoming adults. In the pupae stage, the fly is encased in a protective casing and does not feed. "We predicted they would not produce many antibiotics," said Ms Clarke.
They did not. However the larvae all showed antibacterial properties (except that of the Queensland fruit fly control).
As did all the adult fly species, including the Queensland fruit fly (which at this point requires antibacterial protection because it has contact with other flies and is mobile).
Such properties were present on the fly surface in all four species, although antibacterial properties occur in the gut as well. "You find activity in both places," said Ms Clarke.
"The reason we concentrated on the surface is because it is a simpler extraction.”
The antibiotic material is extracted by drowning the flies in ethanol, then running the mixture through a filter to obtain the crude extract.
When this was placed in a solution with various bacteria including E.coli, Golden Staph, Candida (a yeast) and a common hospital pathogen, antibiotic action was observed every time.
"We are now trying to identify the specific antibacterial compounds," said Ms Clarke. Ultimately these will be chemically synthesised.
Because the compounds are not from bacteria, any genes conferring resistance to them may not be as easily transferred into pathogens. It is hoped this new form of antibiotics will have a longer effective therapeutic life.
المصادر
http://www.abc.net.au/science/news/stories/s689400.htm
http://www.smh.com.au/cgi-bin/common...591671953.html
الان هل للمشككين حجه
هل لهم لسان ليردوا
الترجمه
كانت هناك أغنيه فى اعلان تغنى فيها ذبابه اسمها "لوى" تقول: "أنا سيئه و حقيره و غير نظيفه "
أن يكون الذباب غير نظيف فهذا أمر ليس بمستغرب , و لكن ما الذى يمنع الذباب أن تجتاحه الأمراض ؟؟؟؟
هذا السؤال خطر على بال طالبة دكتوراه اسمها جوان كلارك و زملائها فى معهد العلوم البيولوجيه فى جامعة ماكوارى , عندما كانوا يتناقشون من أين سيأتى الجيل الجديد من المضادات الحيويه
"معظم المضادات الحيويه كانت تستخلص من البكتريا" قالت كلارك , و لكنا استنزفنا هذه المضادات الحيويه بشكل كبير .
صرحت كلارك و مشرفوها الدكتورأندرو بيتى و الدكتور مايكل جيلينجز لمجله علميه : " الميكروبات التى تفرزنوع معين من المضادات الحيويه قد لا تتأثر بهذا المضاد الحيوى على وجه الخصوص , و الا لقتلت نفسها
و لذلك , يبدو أنه يوجد لكل مضاد حيوى تفرزه البكتريا على الاقل طريقه واحده لمقاومة هذا المضاد الحيوى داخل جسم البكتريا
و المشكله الموجوده الأن أن البكتريا أصبح عندها مناعه ضد المضادات الحيويه المستخدمه حاليا
و الفكره من النظر للحشرات لاستخراج مضادات حيويه جديده هى أن البكتريا التى تسبب لنا العديد من المشاكل لن يكون عندها جينات مقاومه لهذه الأنواع الجديده من المضادات الحيويه
والحشرات مصدر رئيسى لمضادات الميكروبات ليس فقط بسبب مكان معيشتها و لكن أيضا بسبب طريقة معيشتها , و كمثال , فى خلية النحل فرد واحد مريض من المكن أن يبيد مستعمرة النحل كاملة , اذا لم يكن هناك طريقه لمنع انتشار هذا المرض بين أفراد المستعمره
قامت كلارك بدراسة الحشرات , مثل ذبابة الخراف و الذبابه المنزليه و ذبابة الخل , و تقول أنها استخدمت ذبابة الفاكهه كمعيار حاكم أو كمقياس
قامت كلارك بدراسة المواد المستخرجه من الأربع ذبابات على أربع أنواع من الميكروبات , كانديدا ييست , الاى كولاى , الجولدن ستاف , و بكتريا التربه المعتاده , و المعروف أن هذه الأنواع الأربعه من البكتريا تسبب العدوى للانسان
اكتشفت كلارك أن الطور البالغ من كل نوع من أنواع الذباب أنتج شيئا تسبب فى منع باقى أنواع الميكروبات من النمو
قالت كلارك أنها بحثت أيضا فى الأطوار المختلفه لحياة كل نوع من أنواع الذباب , و توقعت ألا يكون هناك مضادات حيويه موجوده فى طور أو مرحلة الشرانق , لأنه يوجد للشرانق غلاف وقائى , و لا تتعذى الشرانق فى هذه المرحله و لا يتصلون بباقى أنواع الذباب.......و بصفه عامه وجدت أن هذا صحيح كما توقعت
و كانت الخطوه المنطقيه التاليه أن تقوم باستخلاص وعزل المواد الكيميائيه من الذباب , و لكن الأمر لن يكون سهلا .
و توقف البحث عند هذه النقطه بسبب نقص التمويل
=================================================
ان جسم الذباب هو أخر مكان تتخيله لوجود مضادات حيويه , و بالرغم من هذا فان فريقا من العلماء الاستراليين يركزون جهودهم و أبحاثهم على جسم الذباب من أجل استخلاص المضادات الحيويه .
هناك نظريه تقول أن الذباب عنده مقاومه للميكروبات , و قام هؤلاء العلماء بدراسة الذباب من أجل اكتشاف هذه المضادات فى مراحل حياة الذباب المختلفه
قالت السيده جوان كلارك أن عملهم هو جزء صغير من جهد عالمى كبير من أجل اكتشاف أنواع أخرى من المضادات الحيويه و لكنهم يبحثون فى المكان الذى لم يبحث فيه أحد قبلهم , و التى قدمت نتائج البحث أمام مؤتمر علم الميكروبات هذا الاسبوع فى ميلبورن , و قالت أن هذا المشروع جزء من رسالة الدكتوراه الخاصه بها
قام العلماء بدراسة أربع أنواع من الذباب هى : الذبابه المنزليه و ذبابة الخراف و ذبابة الخل و ذبابة الفاكهه التى استخدمت كمعيار حاكم أو كمقياس و التى تضع بيضها فى الفاكهه الطازجه , و هذه البويضات لا تحتاج لمضادات بكتريا لأنها لا تتصل بالوسط المحيط بها .
الحشرات تمر بأطوار مختلفه فى مراحل الحياه : بداية بالبويضات ثم الشرنقات ثم الطور البالغ , فى طور الشرنقات تكون الذبابه محاطه بغلاف يحميها و لا تتغذى فى هذه المرحله , و لهذا تقول الأنسه كلارك أنهم توقعوا ألا يفرز الذباب مضادات حيويه فى مرحلة الشرانق و كان توقعهم صحيحا
و لكن البويضات أظهرت مقاومه للبكتريا فيما عدا بويضات ذبابة الفاكهه التى استخدمها هؤلاء العلماء كمعيار حاكم أو كمقياس
و أيضا الطور البالغ فى جميع أنواع الذباب أظهر مقاومه للبكتريا بما فيهم الطور البالغ لذبابة الفاكهه , لأنه فى هذه المرحله يتصل مع باقى أنواع الذباب و يكون متحركا .
هذه الخصائص أى خصائص مقاومة البكتريا وجدت على جسم الأنواع الأربعه من الذباب , و كذلك فى الجهاز الهضمى لها , و تقول الدكتوره كلارك أنهم وجدوا خصائص مقاومة البكتريا فى هذين المكانين
و تقول دكتوره كلارك أنهم ركزوا مجهودهم على جسم الذباب الخارجى لسهولة استخلاص ما يحتاجونه من هذا الجزء الخارجى .
و يتم استخلاص المضاد الحيوى عن طريق تغطيس الذباب فى محلول ايثانول , ثم يمرر الخليط من خلال فلتر أو مرشح لاستخلاص هذا المضاد الحيوى .
و عندما يوضع هذا المستخلص فى محلول مع أنواع البكتريا المختلفه مثل : الأى كولاى , و الكانديدا , فانه يلاحظ وجود تأثير المضاد الحيوى فى كل مره .
و تقول دكتوره كلارك أنه الأن يحاولون معرفة ما هى هذه المضادات على وجه التحديد , حتى يتمكنوا فى النهايه من تصنيعها .
و لأن هذه المركبات لم تستخلص من البكتريا , فانه من المأمول أن تستخدم هذه المضادات لفتره طويله لأن البكتيرا لن تتمكن من تكوين مناعه ضدها على المدى المنظور .
أين أنتم يا كفرة يا من تستهزئون بالحديث ليل نهار
أين أنتم يا شيعة يا من تطعنون بأبي هريرة راوي الحديث.........هداكم الله
ملحوظة........الأبحاث متوقفة لقلة التمويل.......كما فى المقال الأول
وبإذن الله سيصلوا للحديث بالحرف.........كن واثقا من هذا........
الله أكبر
أخوكم
الفا
ما هي اخر اخبارك ؟.
تعليق