66 posts · 23,037 views
Exceptions to natural and biological rules are used to increase interest in biology. Recent studies, and not so recent studies, are described in order to demonstrate amazing organisms and practices. Core concepts of biology are emphasized, with side trips into the research of topics that give insight into the evolution and interelatedness of all life.
Mark Lasbury
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- May 15, 2013
- 08:15 AM
- 32 views
Biodiversity Counts!
by Mark Lasbury in As Many Exceptions As Rules
Biodiversity loss is a serious problem. The loss of a single species may have ramifications for every other species. Who knew that a species of fungus would save us from millions of bacterial infection deaths. To drive home the point of diversity, efforts are being made to predict the number of species present on Earth. In the early 1900’s, estimates ranged from 100,000 to 500,000, but 2011 estimates put the number at more like 11.3 million. Bacteria alone could raise this number to 1 bill........ Read more »
Mora, C., Tittensor, D., Adl, S., Simpson, A., & Worm, B. (2011) How Many Species Are There on Earth and in the Ocean?. PLoS Biology, 9(8). DOI: 10.1371/journal.pbio.1001127
ADL, S., SIMPSON, A., FARMER, M., ANDERSEN, R., ANDERSON, O., BARTA, J., BOWSER, S., BRUGEROLLE, G., FENSOME, R., FREDERICQ, S.... (2005) The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists. The Journal of Eukaryotic Microbiology, 52(5), 399-451. DOI: 10.1111/j.1550-7408.2005.00053.x
- May 8, 2013
- 08:10 AM
- 43 views
It's An Airtight Case
by Mark Lasbury in As Many Exceptions As Rules
Humans are relatively weak when it comes to oxygen utilization. We can’t go very long without breathing, while other animals can make much better use of the oxygen they take in and can therefore go longer between breaths. The reasons for these differences are starting to be understood. These include special proteins in the brain to prevent hypoxic damage, and alternate gas exchange pathways, like plastron respiration in ticks. Mycobacterium tuberculosis can survive 50 years in hypoxic cond........ Read more »
Gengenbacher, M., & Kaufmann, S. (2012) Mycobacterium tuberculosis: success through dormancy. FEMS Microbiology Reviews, 36(3), 514-532. DOI: 10.1111/j.1574-6976.2012.00331.x
Fielden, L., Knolhoff, L., Villarreal, S., & Ryan, P. (2011) Underwater survival in the dog tick Dermacentor variabilis (Acari:Ixodidae). Journal of Insect Physiology, 57(1), 21-26. DOI: 10.1016/j.jinsphys.2010.08.009
Williams, T., Zavanelli, M., Miller, M., Goldbeck, R., Morledge, M., Casper, D., Pabst, D., McLellan, W., Cantin, L., & Kliger, D. (2008) Running, swimming and diving modifies neuroprotecting globins in the mammalian brain. Proceedings of the Royal Society B: Biological Sciences, 275(1636), 751-758. DOI: 10.1098/rspb.2007.1484
- May 1, 2013
- 08:10 AM
- 56 views
Venomous Plants – A Hairy Situation
by Mark Lasbury in As Many Exceptions As Rules
There are many thousands of poison plants, but not too many are venomous. The nettles and the dendrocnidaes have hollow spines that deliver neurotoxins when they stab you. Recent research has shown that nettle toxin is beneficial in liver regeneration. It stimulates cell proliferation and reduces apoptosis. In an opposite effect, the dendrocnidae toxin called moroidin is a mitotic spindle inhibitor. It may prove useful as an anticancer drug.... Read more »
Oguz, S., Kanter, M., Erboga, M., Toydemir, T., Sayhan, M., & Onur, H. (2013) Effects of Urtica dioica on oxidative stress, proliferation and apoptosis after partial hepatectomy in rats. Toxicology and Industrial Health. DOI: 10.1177/0748233713480211
Hammond-Tooke, G., Taylor, P., Punchihewa, S., & Beasley, M. (2007) Urtica ferox neuropathy. Muscle , 35(6), 804-807. DOI: 10.1002/mus.20730
- April 24, 2013
- 08:00 AM
- 96 views
A Death Apple A Day Keeps…..
by Mark Lasbury in As Many Exceptions As Rules
Plants are great poison generators. Their toxins can affect skin, heart function, nerve function, or muscle function. In many cases plants make more than one toxin. The manchineel tree for instance, can induce everything from blindness to blisters to swelling of larynx. Oleander is toxic, but for different reasons, and urushiol from poison ivy induces a type IV hypersensitivity. Sounds like none of this is good for humans, but new research studies are showing medicinal values for these plant tox........ Read more »
Bas, A., Demirci, S., Yazihan, N., Uney, K., & Ermis Kaya, E. (2012) Nerium oleander Distillate Improves Fat and Glucose Metabolism in High-Fat Diet-Fed Streptozotocin-Induced Diabetic Rats. International Journal of Endocrinology, 1-10. DOI: 10.1155/2012/947187
Suk, K., Baik, S., Kim, H., Park, S., Paeng, K., Uh, Y., Jang, I., Cho, M., Choi, E., Kim, M.... (2011) Antibacterial Effects of the Urushiol Component in the Sap of the Lacquer Tree (Rhus verniciflua Stokes) on Helicobacter pylori. Helicobacter, 16(6), 434-443. DOI: 10.1111/j.1523-5378.2011.00864.x
Garg, A., Buchholz, T., & Aggarwal, B. (2005) Chemosensitization and Radiosensitization of Tumors by Plant Polyphenols. Antioxidants , 7(11-12), 1630-1647. DOI: 10.1089/ars.2005.7.1630
- April 17, 2013
- 08:15 AM
- 76 views
It’s An All Or None Proposition
by Mark Lasbury in As Many Exceptions As Rules
Venom and venom delivery has evolved independently many times. However, it has never arisen in birds. Recent investigations have found some birds that are toxic, but that is due to their diet, although a recent study indicates that a raptorial ancestor from the Jurassic was venomous.
On the other extreme, every member of the phylum Cnidaria is venomous. From jellyfish to corals to hydras, all cnidarians have nematocysts that fire at extreme speeds with high pressure. A recent review has also........ Read more »
Gong, E., Martin, L., Burnham, D., & Falk, A. (2009) From the Cover: The birdlike raptor Sinornithosaurus was venomous. Proceedings of the National Academy of Sciences, 107(2), 766-768. DOI: 10.1073/pnas.0912360107
Greenwood, P. (2009) Acquisition and use of nematocysts by cnidarian predators. Toxicon, 54(8), 1065-1070. DOI: 10.1016/j.toxicon.2009.02.029
- April 10, 2013
- 08:15 AM
- 150 views
Sneaky Snakes: Biters, Boobytraps, and Spit
by Mark Lasbury in As Many Exceptions As Rules
Venomous snakes get more attention than non-venomous snakes. But the toxicofera hypothesis suggests that all snakes were at one time venomous, and only some have lost the ability. New studies are pointing to even weirder snakes that are venomous and poisonous – like the keelback snakes that have toxin glands on their necks to deter predators while they also have venom to subdue prey. Or the spitting cobras, whose venom can also act as a poison; it works on the surface and when injected.... Read more »
Vonk, F., Admiraal, J., Jackson, K., Reshef, R., de Bakker, M., Vanderschoot, K., van den Berge, I., van Atten, M., Burgerhout, E., Beck, A.... (2008) Evolutionary origin and development of snake fangs. Nature, 454(7204), 630-633. DOI: 10.1038/nature07178
Mori, A., Burghardt, G., Savitzky, A., Roberts, K., Hutchinson, D., & Goris, R. (2011) Nuchal glands: a novel defensive system in snakes. Chemoecology, 22(3), 187-198. DOI: 10.1007/s00049-011-0086-2
Hutchinson, D., Mori, A., Savitzky, A., Burghardt, G., Wu, X., Meinwald, J., & Schroeder, F. (2007) From the Cover: Dietary sequestration of defensive steroids in nuchal glands of the Asian snake Rhabdophis tigrinus. Proceedings of the National Academy of Sciences, 104(7), 2265-2270. DOI: 10.1073/pnas.0610785104
- April 3, 2013
- 08:15 AM
- 115 views
A Salamander Superhero?
by Mark Lasbury in As Many Exceptions As Rules
The Spanish ribbed salamander, Pleurodeles waltl, can stick it ribs through its skin in order to inject poison on its skin into a potential predator. As such, it is both poisonous and venomous. This is exceptional for any animal, but is only one of many toxic exceptions in the amphibians. New research is showing that one poisonous toad can actually squirt it toxin at a predator from a distance, while frogs and toads previously described as sequestering toxins from their diet are also capable of ........ Read more »
Savitzky, A., Mori, A., Hutchinson, D., Saporito, R., Burghardt, G., Lillywhite, H., & Meinwald, J. (2012) Sequestered defensive toxins in tetrapod vertebrates: principles, patterns, and prospects for future studies. Chemoecology, 22(3), 141-158. DOI: 10.1007/s00049-012-0112-z
Heiss, E., Natchev, N., Salaberger, D., Gumpenberger, M., Rabanser, A., & Weisgram, J. (2010) Hurt yourself to hurt your enemy: new insights on the function of the bizarre antipredator mechanism in the salamandrid . Journal of Zoology, 280(2), 156-162. DOI: 10.1111/j.1469-7998.2009.00631.x
Trefaut Rodrigues, M., Felipe Toledo, L., Kruth Verdade, V., Maria Antoniazzi, M., & Jared, C. (2011) The Amazonian toad Rhaebo guttatus is able to voluntarily squirt poison from the paratoid macroglands. Amphibia-Reptilia, 32(4), 546-549. DOI: 10.1163/156853811X603724
- March 27, 2013
- 08:30 AM
- 174 views
Hang A Question Mark On It
by Mark Lasbury in As Many Exceptions As Rules
Recent studies have expanded the list of venomous lizards. Phylogenetic studies indicate that venom evolved in the reptiles almost 100 million before the first snakes, making the lizards the developers of reptile venom systems. In 2006, the monitor lizards and iguanas were added to the list of venomous reptiles, and they are very important to the evolution of venom glands. It was previously believed that lizard and snake venoms evolved independently.
These studies have led to the Toxicofera H........ Read more »
Fry, B., Vidal, N., Norman, J., Vonk, F., Scheib, H., Ramjan, S., Kuruppu, S., Fung, K., Blair Hedges, S., Richardson, M.... (2005) Early evolution of the venom system in lizards and snakes. Nature, 439(7076), 584-588. DOI: 10.1038/nature04328
Fry, B., Wroe, S., Teeuwisse, W., van Osch, M., Moreno, K., Ingle, J., McHenry, C., Ferrara, T., Clausen, P., Scheib, H.... (2009) A central role for venom in predation by Varanus komodoensis (Komodo Dragon) and the extinct giant Varanus (Megalania) priscus. Proceedings of the National Academy of Sciences, 106(22), 8969-8974. DOI: 10.1073/pnas.0810883106
Fry, B., Winter, K., Norman, J., Roelants, K., Nabuurs, R., van Osch, M., Teeuwisse, W., van der Weerd, L., Mcnaughtan, J., Kwok, H.... (2010) Functional and Structural Diversification of the Anguimorpha Lizard Venom System. Molecular , 9(11), 2369-2390. DOI: 10.1074/mcp.M110.001370
- March 20, 2013
- 08:29 AM
- 188 views
The Best Offense Is A Good Defense
by Mark Lasbury in As Many Exceptions As Rules
Mammals employ a number and variety of defensive ploys and behaviors, but only a few have evolved toxins. A new study shows just how the African Crested Rat uses the oubain contained in the Acokanthera tree bark and roots to deter potential predators. Hollow hairs on its flanks soak up the toxic saliva produced by chewing the bark, and the rat presents his flanks to threatening animals.
This is an example of toxin sequestering, but and few mammals go even further. Platypuses, slow lorises, s........ Read more »
Broom, M., & Ruxton, G. (2012) Perceptual advertisement by the prey of stalking or ambushing predators. Journal of Theoretical Biology, 9-16. DOI: 10.1016/j.jtbi.2012.08.026
Kingdon, J., Agwanda, B., Kinnaird, M., O'Brien, T., Holland, C., Gheysens, T., Boulet-Audet, M., & Vollrath, F. (2011) A poisonous surprise under the coat of the African crested rat. Proceedings of the Royal Society B: Biological Sciences, 279(1729), 675-680. DOI: 10.1098/rspb.2011.1169
Whittington, C., Koh, J., Warren, W., Papenfuss, A., Torres, A., Kuchel, P., & Belov, K. (2009) Understanding and utilising mammalian venom via a platypus venom transcriptome. Journal of Proteomics, 72(2), 155-164. DOI: 10.1016/j.jprot.2008.12.004
- March 13, 2013
- 08:00 AM
- 235 views
One Man’s Poison Is Another Man’s Cure
by Mark Lasbury in As Many Exceptions As Rules
In the early 16th century Paracelsus stated that it is the dose that makes the poison. He had to be thinking about botulinum toxin. This most potent of all toxins known to man has been used as a cosmetic agent for several years, but is now moving into the realm of the necessary pharmacopia, not merely the vanity market.
Use as a muscle relaxant in spasmodic dysphonic and even plantar fasciitis is common now, but a new study links botulinum toxin to chronic pain treatment. It seems that opiod........ Read more »
Vacca, V., Marinelli, S., Luvisetto, S., & Pavone, F. (2013) Botulinum toxin A increases analgesic effects of morphine, counters development of morphine tolerance and modulates glia activation and μ opioid receptor expression in neuropathic mice. Brain, Behavior, and Immunity. DOI: 10.1016/j.bbi.2013.01.088
- March 6, 2013
- 08:00 AM
- 231 views
A Marriage Of Inconvenience
by Mark Lasbury in As Many Exceptions As Rules
In terms of parthenogenesis, some organisms adopt it as a survival mechanism, some can do it if no males are present, but others have it thrust upon them by intracellular parasites. Wolbachia species can induce arthropods and some nematodes to produce only female offspring, since the parasites are transmitted vertically from mother to daughter.
Recent research in a parasitic wasp shows how a defense against this infection may work. The PSR chromosome in haplodiploid males forces a male sex b........ Read more »
Swim, M., Kaeding, K., & Ferree, P. (2012) Impact of a selfish B chromosome on chromatin dynamics and nuclear organization in Nasonia. Journal of Cell Science, 125(21), 5241-5249. DOI: 10.1242/jcs.113423
Simon, J., Boutin, S., Tsuchida, T., Koga, R., Le Gallic, J., Frantz, A., Outreman, Y., & Fukatsu, T. (2011) Facultative Symbiont Infections Affect Aphid Reproduction. PLoS ONE, 6(7). DOI: 10.1371/journal.pone.0021831
- February 27, 2013
- 08:15 AM
- 248 views
The Yolk's On You
by Mark Lasbury in As Many Exceptions As Rules
Parthenogenesis has been recognized in several species of captive bird, but t is not known if this occurs in the wild. Parthenogenesis is possible in birds as they do not undergo genomic imprinting, but the vast majority of unfertilized egg development in birds results in early embryo mortality, usually in the 3-5 day range. A single species of turkey, the Beltsville Small White, was bred to increase the number of parthenogenic embryos, and in the same process, these eggs developed later and lat........ Read more »
Parker, H., Kiess, A., Robertson, M., Wells, J., & McDaniel, C. (2012) The relationship of parthenogenesis in virgin Chinese Painted quail (Coturnix chinensis) hens with embryonic mortality and hatchability following mating1. Poultry Science, 91(6), 1425-1531. DOI: 10.3382/ps.2011-01692
- February 20, 2013
- 08:25 AM
- 225 views
Males – Can’t Live Without Them?
by Mark Lasbury in As Many Exceptions As Rules
Parthenogenesis takes many forms and employs several mechanisms. There are facultative and obligate parthenogenic species that can carry out the process on their own, but other, especially obligate species, that need help to stimulate unfertilized egg development. Called gynogenesis or sperm-dependent parthenogenesis, all female species will mate with males of a closely related species. While the sperm do stimulate egg development, they do not contribute to the genome of the embryo. A recent pub........ Read more »
Chen, Y., Ai, A., Tang, Z., Zhou, G., Liu, W., Cao, Y., & Zhang, W. (2012) Mesenchymal-Like Stem Cells Derived from Human Parthenogenetic Embryonic Stem Cells. Stem Cells and Development, 21(1), 143-151. DOI: 10.1089/scd.2010.0585
Alberici da Barbiano, L., Aspbury, A., Nice, C., & Gabor, C. (2011) The impact of social context on male mate preference in a unisexual-bisexual mating complex. Journal of Fish Biology, 79(1), 194-204. DOI: 10.1111/j.1095-8649.2011.03009.x
- February 13, 2013
- 08:20 AM
- 268 views
Just Leave The “Father” Line Blank
by Mark Lasbury in As Many Exceptions As Rules
Parthenogenesis involves the stimulation of unfertilized eggs to undergo development. In most cases, haploid eggs are not helpful in this type of asexual reproduction, so eggs will either be produced in a diploid form (apomixis) or diploidy will need to be recovered (automixis). The sex determination system will determine which sex the offspring of aprthenogenetic births will be, but mammals get left out of this equation. Genomic imprinting in mammals requires inputs from both male and female. A........ Read more »
Renfree, M., Suzuki, S., & Kaneko-Ishino, T. (2012) The origin and evolution of genomic imprinting and viviparity in mammals. Philosophical Transactions of the Royal Society B: Biological Sciences, 368(1609), 20120151-20120151. DOI: 10.1098/rstb.2012.0151
- February 6, 2013
- 08:15 AM
- 240 views
Exceptions Give Birth To Exceptions
by Mark Lasbury in As Many Exceptions As Rules
Parthenogenesis was first described in the late 1800’s, but examples of natural parthenogenesis have been limited to amphibians and reptiles until recently. The birth of hammerhead and bonnethead sharks have been proven to be parthenogenetic, while 2012 saw the first published report of pit vipers undergoing parthenogenesis in the wild.
Molecular biology has afforded more in depth study of parthenogenesis in a multitude of species, and new research is showing a plethora of mechanisms a........ Read more »
Booth, W., Smith, C., Eskridge, P., Hoss, S., Mendelson, J., & Schuett, G. (2012) Facultative parthenogenesis discovered in wild vertebrates. Biology Letters, 8(6), 983-985. DOI: 10.1098/rsbl.2012.0666
Kellner, K., Seal, J., & Heinze, J. (2013) Sex at the margins: parthenogenesis vs. facultative and obligate sex in a Neotropical ant. Journal of Evolutionary Biology, 26(1), 108-117. DOI: 10.1111/jeb.12025
Neiman, M., Paczesniak, D., Soper, D., Baldwin, A., & Hehman, G. (2011) WIDE VARIATION IN PLOIDY LEVEL AND GENOME SIZE IN A NEW ZEALAND FRESHWATER SNAIL WITH COEXISTING SEXUAL AND ASEXUAL LINEAGES. Evolution, 65(11), 3202-3216. DOI: 10.1111/j.1558-5646.2011.01360.x
- February 2, 2013
- 07:00 AM
- 234 views
Take Off Your Coat And Stay Awhile
by Mark Lasbury in As Many Exceptions As Rules
The naked mole rat is an amazing animal for many reasons. One – it’s a naked mammal, more naked than dolphins or even mexican hairless dogs! The reason for hairlessness is just a special in the mole rat, they are ectothermic – a cold blooded mammal. The environment and life style of the naked mole rat makes hair either a disadvantage or moot, so over time it has gone away.
One part of the mole rat lifestyle is eusociality; like many insects there is a queen and a caste syst........ Read more »
Kutsukake, N., Inada, M., Sakamoto, S., & Okanoya, K. (2012) A Distinct Role of the Queen in Coordinated Workload and Soil Distribution in Eusocial Naked Mole-Rats. PLoS ONE, 7(9). DOI: 10.1371/journal.pone.0044584
- January 30, 2013
- 08:15 AM
- 311 views
Carp Diem - Polyploid Fish Seize The Day
by Mark Lasbury in As Many Exceptions As Rules
Commerical fisheries and the aquaculture industry have contributed much to the study of polyploidy in fish. But the arguments still rage as to the long-term effects of the production of polyploids. Triploidy is often induced through temperature or chemical shock, and this is supposed to produce sterile offspring, letting growers harvest the larger and healthier stocks. But are they healthier?
Recent debate and study has looked into the fitness of polyploidy organisms. Conventional wisdom, ba........ Read more »
Ashfield, T., Egan, A., Pfeil, B., Chen, N., Podicheti, R., Ratnaparkhe, M., Ameline-Torregrosa, C., Denny, R., Cannon, S., Doyle, J.... (2012) Evolution of a Complex Disease Resistance Gene Cluster in Diploid Phaseolus and Tetraploid Glycine. PLANT PHYSIOLOGY, 159(1), 336-354. DOI: 10.1104/pp.112.195040
King, K., Seppala, O., & Neiman, M. (2012) Is more better? Polyploidy and parasite resistance. Biology Letters, 8(4), 598-600. DOI: 10.1098/rsbl.2011.1152
- January 26, 2013
- 07:15 AM
- 329 views
Gimme Me Some Dihydrogen Monoxide
by Mark Lasbury in As Many Exceptions As Rules
One cannot underestimate the ways that water affects life on Earth. Beyond its chemical properties, some animals have evolved to substitute water for a rigid skeleton. Hydrostatic skeletons can be used for support, but also as water vascular systems that provide pressure for vascular transport and respiration. A recent review by William H. Kier sheds light on the interactions of connective tissue fibers, muscular fibers, and water that provide the agonist/antagonist pressure muscular movement, b........ Read more »
Kier, W. (2012) The diversity of hydrostatic skeletons. Journal of Experimental Biology, 215(8), 1247-1257. DOI: 10.1242/jeb.056549
- January 23, 2013
- 08:25 AM
- 269 views
An Evolutionary Ploy Employing Polyploidy
by Mark Lasbury in As Many Exceptions As Rules
Polyploid humans do not survive the womb, but polyploid plants are the norm rather than the exception. Polyploidization offers a plant chances to become a new species through neofunctionalization, and also offers the chance to adapt to new environments. New research is showing that the gigas effect on cell size in polyploid cytotypes also alters the water potential and drought resistance for the desert bush, Atriplex canescens. Comparison of diploid, triploid, and tetraploid cytotypes shows that........ Read more »
Hao GY, Lucero ME, Sanderson SC, Zacharias EH, Holbrook NM. (2012) Polyploidy enhances the occupation of heterogeneous environments through hydraulic related trade-offs in Atriplex canescens (Chenopodiaceae). New Phytol. info:/
SALMON, A., AINOUCHE, M., & WENDEL, J. (2005) Genetic and epigenetic consequences of recent hybridization and polyploidy in Spartina (Poaceae). Molecular Ecology, 14(4), 1163-1175. DOI: 10.1111/j.1365-294X.2005.02488.x
Guo M, Davis D, Birchler JA. (1996) Dosage effects on gene expression in a maize ploidy series. Trends in Genetics, 12(8), 293. DOI: 10.1016/0168-9525(96)81463-6
- January 19, 2013
- 06:30 AM
- 306 views
Look Who’s Talking
by Mark Lasbury in As Many Exceptions As Rules
Oral language is a definite delineation between humans and other animals. There are several anatomical differences that make speech possible in humans, but there are also molecular differences, including the sequence of the fox2p transcription factor.
Recent evidence has shown the importance of the fox2p protein in functions related to speech, in addition to affecting speech directly. One study has shown that motor learning in response to auditory cues is also dependent on fox2p function. Ei........ Read more »
Kurt, S., Fisher, S., & Ehret, G. (2012) Foxp2 Mutations Impair Auditory-Motor Association Learning. PLoS ONE, 7(3). DOI: 10.1371/journal.pone.0033130
Li, T., Zeng, Z., Zhao, Q., Wang, T., Huang, K., Li, J., Li, Y., Liu, J., Wei, Z., Wang, Y.... (2012) FoxP2 is significantly associated associated with schizophrenia and major depression in the Chinese Han Population . World Journal of Biological Psychiatry, 1-5. DOI: 10.3109/15622975.2011.615860
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