Interspecies chimera between primate embryonic stem cells and mouse embryos: monkey ESCs engraft into mouse embryos, but not post-implantation fetuses

Unequivocal evidence for pluripotency in which embryonic stem cells contribute to chimeric offspring has yet to be demonstrated in human or nonhuman primates (NHPs). Here, rhesus and baboons ESCs were investigated in interspecific mouse chimera generated by aggregation or blastocyst injection. Aggregation chimera produced mouse blastocysts with GFP-nhpESCs at the inner cell mass (ICM), and embryo transfers (ETs) generated dimly-fluorescencing abnormal fetuses. Direct injection of GFP-nhpESCs into blastocysts produced normal non-GFP-fluorescencing fetuses. Injected chimera showed >70% loss of GFP-nhpESCs after 21 h culture. Outgrowths of all chimeric blastocysts established distinct but separate mouse- and NHP-ESC colonies. Extensive endogenous autofluorescence compromised anti-GFP detection and PCR analysis did not detect nhpESCs in fetuses. NhpESCs localize to the ICM in chimera and generate pregnancies. Because primate ESCs do not engraft post-implantation, and also because endogenous autofluorescence results in misleading positive signals, interspecific chimera assays for pluripotency with primate stem cells is unreliable with the currently available ESCs. Testing primate ESCs reprogrammed into even more na?ve states in these inter-specific chimera assays will be an important future endeavor.     

Sampling bee communities using pan traps: alternative methods increase sample size

Bees play an important role in natural and agricultural landscapes and increased interest in these pollinators has lead to an increase in studies designed to monitor bee populations across the globe. Many studies investigating bee diversity use pan traps (colored plastic bowls filled with soapy water) as a cost-effective trapping method. Here we investigate how alternative pan trap designs (both the size of the traps, and the addition of “nectar guides”) affect the number of specimens collected. We find that larger pan traps collect more specimens than small and medium sized traps, and that the addition of “nectar guides” can significantly increase the number of specimens collected. Increased sample sizes can lead to a better understanding of patterns of bee diversity, which can lead to more informed management decisions.     

Morphological Observations on Brevipalpus phoenicis (Acari: Tenuipalpidae) Including Comparisons with B. californicus and B. obovatus

The genus Brevipalpus has over 300 species worldwide. The three most important agricultural pest species in the genus, Brevipalpus californicus (Banks), B. obovatus Donnadieu, and B. phoenicis (Geijskes), have been consistently confused and misidentified for more than 50 years. The present study provides a discussion of the characters and character states used to separate these mites. Low-temperature scanning electron microscopy and traditional light microscopy techniques were used to illustrate the subtle morphological differences between these three species. Morphology of the dorsal propodosoma, opisthosoma, and leg chaetotaxy of all three species was examined and compared. The number of dorsal setae, the number of solenidia (omega) on tarsus II, and dorsal cuticular patterns were the most important characters in the identification of Brevipalpus species. B. phoenicis is similar to B. californicus in having two omega on tarsus leg II and different from B. obovatus which has only one omega on tarsus leg II and similar to B. obovatus in having only one pair of F setae (f3), but differing from B. californicus which has two pairs of F setae (f2-3). The dorsal opisthosomal and propodisomal cuticular patterns frequently used to distinguish between these three species are useful but one must be aware that age, feeding, and mounting techniques can affect the appearance of these characters.     

Transposon mutagenesis of Mycoplasma gallisepticum

There are few systems available for studying the genetics of the important avian respiratory pathogen, Mycoplasma gallisepticum. These techniques are needed to develop a mechanism to study the molecular pathogenesis of M. gallisepticum. Tn916 has the ability to transpose into the M. gallisepticum genome by both transformation and conjugation. In this study, PEG-mediated transformation was employed for the transfer of Tn916 into M. gallisepticum and create a transposon mutant library. Transformants were obtained at a frequency of approximately 5 x 10(-8) per recipient CFU. A total of 424 MG/Tn916 mutants were constructed and sequence data from the transposon junctions of 71 mutants was obtained and used to identify transposon insertion sites. Insertions were found throughout the genome in nearly all of the major gene categories, making this the first extensive characterization of a transposon mutant library of M. gallisepticum. Transposon stability was also examined, and it was determined that for two mutants the element was stably maintained in vivo in the absence of selective pressure.