生物谷报道：密集地居住在一起、过着有秩序的集体生活有什么好处？一群研究蜜蜂的澳大利亚科学家会告诉你，这能增强生物抵抗细菌的能力。
据美国《科学》杂志网站报道，这个研究小组新近发现，群体生活使蜜蜂具有格外强的免疫力，而且蜂群越大、越密集，蜜蜂抵抗疾病的能力越强。这是人们头一次找到免疫系统进化与社会行为之间有关的确切证据，将为研制下一代抗生素提供线索。
群居的生物感染疾病的危险较高，昆虫和人类都是这样。很久以来科学家一直猜测，蜜蜂和其他群居的昆虫可能进化出了较强的抗病能力，例如分泌抗菌物质覆盖体表，以此对抗群居生活的危险。群落越大、越密集，环境压力就越大，促使昆虫进化出更强的抗病能力，而这又反过来促使群落进一步变大。
为了检验这一理论，澳大利亚新南威尔士大学和南澳大利亚博物馆的科学家收集了多种蜜蜂，其中有的独来独往，根本不过社会化生活；有的半社会化，与姐妹和后代组成小群落生活；有的生活在高度社会化的大集体中，分工明确。科学家将这些蜜蜂体表的保护层洗掉，将所得的溶液来处理金黄色葡萄球菌，进行观察。
结果显示，所有含蜜蜂体表物质的溶液都能杀死细菌，但社会化生活的蜜蜂的体表物质抗菌能力比人们原先预料的高得多。与最孤僻的蜜蜂相比，最社会化的蜜蜂体表物质抗菌能力要高出３１４倍，仅轻度社会化的蜜蜂也高出１０倍多。这一结果发表在最新一期《生物学通讯》上。
研究人员说，蜜蜂和其他昆虫分泌的抗菌物质，可望用来研制下一代抗生素。
英文原文：
Science，Daily News Archive > 2007 > May > 16 May (Telis)
The Benefits of Bee-ing Social
By Gisela Telis
ScienceNOW Daily News
16 May 2007
Social bees have surprisingly strong body armor against microbes, researchers have found. And the more gregarious the bees--the larger their colonies and the more closely related--the better they are at beating disease. The discovery is the first clear link between the evolution of immune systems and social behavior, and it dangles a new hope for bioprospectors on the trail of the next generation of antibiotics.
Insects, like humans, face greater risks of catching and spreading infectious diseases when they're crowded together. Scientists have long suspected that bees and other bugs combat the added risk that being social incurs by evolving stronger disease defenses, such as secreting antimicrobial agents to cover their bodies. The theory is that bigger colonies with more crowded conditions would require insects to evolve better immune defenses, which in turn enable the insects to evolve still-bigger colonies.
To test the idea, biologists Adam Stow, Andrew Beattie, and their colleagues at Macquarie University in New South Wales and the South Australian Museum in Adelaide collected bees from across the social spectrum: blue-banded bees and teddy bear bees, which are solitary and live in their own nests without partners or workers; semisocial reed bees that partner with their sisters and their offspring in small colonies; and Australian native honey bees, which form large colonies of closely related individuals with sophisticated divisions of labor. The scientists then washed the protective coatings from the bees' bodies and applied the resulting solution to the notorious Staphylococcus aureus (staph) bacterium.
By measuring how much of each solution it took to stop the staph's growth, the researchers determined the strength of each kind of bee's body coating. All the coatings killed bacteria, but the social bees' antimicrobials proved much more powerful than expected, says Stow. Antimicrobial armor from the most social bees was 314 times stronger than that from the most solitary bees, the team reports online this week in Biology Letters, and even the most mildly social bees were 10 times more protected than their solitary counterparts.
The mysterious bacteria-busting secretions of bees and other insects could someday offer an alternative to today's antibiotics, says Stow. "If you're going to look in nature for antibiotics," he says, "this tells you where to look."
For Oxford ecologist Robert May, the finding is crucial and long overdue. "While the idea isn't new, the demonstration is clear, elegant, and the first,?he says. "It's just very nice."
原始出处:
Biology Letters，10.1098/rsbl.2007.0178
Antimicrobial defences increase with sociality in bees Adam Stow, David Briscoe, Michael Gillings, Marita Holley, Shannon Smith, Remko Leys, Tish Silberbauer, Christine Turnbull, Andrew Beattie
