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Quantum tunneling rotors in a zeolitic imidazolate framework ZIF-8 can provide insights into local gas adsorption sites and local dynamics of porous structure, which are inaccessible to standard physisorption or x-ray diffraction sensitive primarily to long-range order. Using in situ high-resolution inelastic neutron scattering at 3 K, we follow the evolution of methyl tunneling with respect to the number of dosed gas molecules. While nitrogen adsorption decreases the energy of the tunneling peak, and ultimately hinders it completely (0.33 meV to zero), argon substantially increases the energy to 0.42 meV. Ab initio calculations of the rotational barrier of ZIF-8 show an exception to the reported adsorption sites hierarchy, resulting in anomalous adsorption behavior and linker dynamics at subatmospheric pressure. The findings reveal quantum tunneling rotors in metal-organic frameworks as a sensitive atomistic probe of local physicochemical phenomena.

The Gram-negative Burkholderia genus includes several species or intracellular bacterial pathogens that pose substantial risk to humans. Jn this study, we have generated draft genome sequences of 15 strains of B. okklhomensis, B. pseudomaUei, B. thaiklndensis, and B. ubonensis to an average sequence read coverage of 25 to 40-fold., Pub. in Journal of Bacteriology, v192 n23, p6313-6314, Dec 2010.

Chlamydia pneumoniae is an important human respiratory pathogen that is responsible for an estimated 10% of community-acquired pneumonia and 5% of bronchitis and sinusitis cases. We examined changes in global protein expression profiles associated with the redifferentiation of reticulate body (RB) to elementary body (EB) as C. pneumoniae cells progressed from 24 to 48 h postinfection in HEp2 cells. Proteins corresponding to those showing the greatest changes in abundance in the beginning of the RB to EB transition were then identified from purified EBs. Among the 300 spots recognized, 35 proteins that were expressed at sufficiently high levels were identified by mass spectrometry. We identified C. pneumoniae proteins that showed more than 2-fold increases in abundance in the early stages of RB to EB transition, including several associated with amino acid and cofactor biosynthesis (Ndk, TrxA, Adk, PyrH, and BirA), maintenance of cytoplasmic protein function (GroEL/ES, DnaK, DksA, GrpE, HtrA, ClpP, ClpB, and Map), modification of the bacterial cell surface (CrpA, OmpA, and OmcB), energy metabolism (Tal and Pyk), and the putative transcriptional regulator TctD. This study identified C. pneumoniae proteins involved in the process of redifferentiation into mature, infective EBs and indicates bacterial metabolic pathways that may be involved in this transition. The proteins involved in RB to EB transition are key to C. pneumoniae infection and are perhaps suitable targets for therapeutic intervention.

*This article is free to read on the publisher's website* ...Shortly after Moulder (79) definitively reported the bacterial nature of chlamydiae in 1966, the genus Chlamydia was established (86) and divided into two species, Chlamydia trachomatis and Chlamydia psittaci (85). Chlamydia pneumoniae (42) and Chlamydia pecorum (34), formerly known as strains of C. psittaci, were designated as distinct species in 1989 and 1992, respectively. More recently, a new taxonomy was proposed that increases the number of species in the family Chlamydiaceae to nine and groups these species into two genera (31). However, this review will not use the emended taxonomy, since much debate continues on the issue (106). ...