20 research outputs found
A tool for determination of the three-dimensional orientation of electronic transition dipole moments and identification of configurational isomers
A method is presented that combines femtosecondpolarization resolved
UV/visible pump–IR probe spectroscopy and density functional theory
calculations in determining the three-dimensional orientation of an electronic
transition dipole moment (tdm) within the molecular structure. The method is
demonstrated on the approximately planar molecule coumarin 314 (C314)
dissolved in acetonitrile, which can exist in two ground state configurations:
the E- and the Z-isomer. Based on an exhaustive search analysis on
polarization resolved measurement data for four different vibrational modes,
it is concluded that C314 in acetonitrile is the E-isomer. The electronic tdm
vector for the electronic S0→S1 transition is determined and the analysis
shows that performing the procedure for four vibrational modes instead of the
minimally required three reduces the 1σ probability area from 2.34% to 2.24%
of the solution space. Moreover, the fastest rotational correlation timeτc for
the C314 E-isomer is determined to be 26±2 ps
An angle balanced polarization resolved femtosecond VIS pump–IR probe study
Photoisomerization of biliverdin (BV) chromophore triggers the photoresponse
in native Agp1 bacteriophytochrome. We discuss heterogeneity in phytochrome Pr
form to account for the shape of the absorption profile. We investigated
different regions of the absorption profile by angle balanced polarization
resolved femtosecond VIS pump–IR probe spectroscopy. We studied the Pr form of
Agp1 with its natural chromophore and with a sterically locked 18Et-BV (locked
Agp1). We followed the dynamics and orientations of the carbonyl stretching
vibrations of ring D and ring A in their ground and electronically excited
states. Photoisomerization of ring D is reflected by strong signals of the
ring D carbonyl vibration. In contrast, orientational data on ring A show no
rotation of ring A upon photoexcitation. Orientational data allow excluding a
ZZZasa geometry and corroborates a nontwisted ZZZssa geometry of the
chromophore. We found no proof for heterogeneity but identified a new, to our
knowledge, electronic transition in the absorption profile at 644 nm (S0→S2).
Excitation of the S0→S2 transition will introduce a more complex photodynamics
compared with S0→S1 transition. Our approach provides fundamental information
on disentanglement of absorption profiles, identification of chromophore
structures, and determination of molecular groups involved in the
photoisomerization process of photoreceptors
Bovine tuberculosis and brucellosis in cattle and African buffalo in the Limpopo National Park, Mozambique
Bovine tuberculosis (BTB) and brucellosis are prevalent in buffaloes of the Kruger
National Park (KNP, South Africa). Both diseases were considered to have no or
a very low prevalence in wildlife and livestock in and around the Limpopo
National Park (LNP, Mozambique). The same applies for tuberculosis in Gonarezhou
National Park (GNP, Zimbabwe), but just recently, BTB was detected in
buffaloes in the GNP and fears arose that the disease might also spread to the
LNP as a result of the partial removal of the fences between the three parks to
form the Great Limpopo Transfrontier Park. To assess the status of both diseases
in and around LNP, 62 buffaloes were tested for bovine tuberculosis (BTB) and
bovine brucellosis. The percentage of positive BTB reactors in buffalo was 8.06%
using BovidTB Stat-Pak and 0% with BOVIGAM IFN-c test and IDEXX
ELISA. The brucellosis seroprevalence in buffalo was found to be 17.72% and
27.42% using Rose Bengal Test (RBT) and ELISA, respectively. In addition, 2445
cattle in and around the LNP were examined for BTB using the single intradermal
cervical comparative tuberculin test (SICCT), and an apparent prevalence of
0.98% was found with no significant difference inside (0.5%) and outside (1.3%)
the park. This is the first published report on the presence of positive reactors to
BTB and bovine brucellosis in buffalo and cattle in and outside the LNP. Monitoring
the wildlife–livestock–human interface of zoonotic high-impact diseases
such as BTB and brucellosis is of outmost importance for the successful implementation
and management of any transfrontier park that aims to improve the
livelihoods of the local communities.German Research Foundation (DFG).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-16822016-12-31hb2016Veterinary Tropical Disease
Faster progression to AIDS and AIDS-related death among seroincident individuals infected with recombinant HIV-1 A3/CRF02_AG compared to sub subtype A3.
HIV-1 is divided into different subtypes and circulating recombinant forms (CRFs) but the impact of HIV-1 subtype/CRF on disease progression is not fully understood. We determined the HIV-1 subtype/CRF of 152 seroincident individuals from Guinea-Bissau, based on the C2-V3 region of env. Rate of disease progression was measured as time from estimated seroconversion to AIDS and AIDS-related death. Hazard ratios (HRs) were calculated using a Cox proportional hazard model, adjusting for gender and age at seroconversion. The major subtypes/CRFs identified were CRF02_AG (53%), A3 (29%) and A3/02 (a recombinant of A3 and CRF02_AG) (13%). Infection with A3/02 was associated with a close to 3-fold increased risk of AIDS and AIDS-related death compared to A3 (HR=2.6 [P=0.011] and 2.9 [P=0.032], respectively). The median estimated time from seroconversion to AIDS and AIDS-related death was 5.0 and 8.0 years for A3/02, 6.2 and 9.0 years for CRF02_AG and 7.2 and 11.3 years for A3. Our results show that there are significant differences in disease progression between HIV-1 A-like subtypes/CRFs. Individuals infected with the A3/02 recombinant have among the fastest progression rates to AIDS reported to date. Determining the HIV-1 subtype of infected individuals could be of importance in the management of HIV-1 infections