Lund University

About: Lund University is a education organization based out in Lund, Sweden. It is known for research contribution in the topics: Population & Cancer. The organization has 42345 authors who have published 124676 publications receiving 5016438 citations. The organization is also known as: Lunds Universitet & University of Lund.

Quantum control of energy flow in light harvesting.

Abstract: Coherent light sources have been widely used in control schemes that exploit quantum interference effects to direct the outcome of photochemical processes. The adaptive shaping of laser pulses is a particularly powerful tool in this context: experimental output as feedback in an iterative learning loop refines the applied laser field to render it best suited to constraints set by the experimenter. This approach has been experimentally implemented to control a variety of processes, but the extent to which coherent excitation can also be used to direct the dynamics of complex molecular systems in a condensed-phase environment remains unclear. Here we report feedback-optimized coherent control over the energy-flow pathways in the light-harvesting antenna complex LH2 from Rhodopseudomonas acidophila, a photosynthetic purple bacterium. We show that phases imprinted by the light field mediate the branching ratio of energy transfer between intra- and intermolecular channels in the complex's donor acceptor system. This result illustrates that molecular complexity need not prevent coherent control, which can thus be extended to probe and affect biological functions.

Enzymatic activity of prostate-specific antigen and its reactions with extracellular serine proteinase inhibitors.

Abstract: Prostate-specific antigen (PSA) is one of the three most abundant prostatic-secreted proteins in human semen. It is a serine proteinase that, in its primary structure, manifests extensive similarities with that of the Arg-restricted glandular kallikrein-like proteinases. When isolated from semen by the addition of chromatography on aprotinin-Sepharose to a previously described procedure, PSA displayed chymotrypsin-like activity and cleaved semenogelin and the semenogelin-related proteins in a rapid and characteristic pattern, but had no trypsin-like activity. About one third of the purified protein was found to be enzymatically inactive, due to cleavage carboxy-terminal of Lys145. Active PSA formed SDS-stable complexes with alpha 1-antichymotrypsin, alpha 2-macroglobulin-analogue pregnancy zone protein. PSA formed inhibitory complexes with alpha 1-antichymotrypsin at a molar ratio of 1:1, a reaction in which PSA cleaved the inhibitor in a position identical to that reported from the reaction between chymotrypsin and alpha 1-antichymotrypsin. The formation of stable complexes between PSA and alpha 1-antichymotrypsin occurred at a much slower rate than that between chymotrypsin and alpha 1-antichymotrypsin, and at a similar or slightly slower rate than that between PSA and alpha 2-macroglobulin. When added to normal blood plasma in vitro, active PSA formed stable complexes both with alpha 2-macroglobulin and alpha 1-antichymotrypsin. This complex formation may be a crucial determinant of the turnover of active PSA in intercellular fluid or blood plasma in vivo.

Economic Burden of Obesity: A Systematic Literature Review

Abstract: Background: The rising prevalence of obesity represents an important public health issue. An assessment of its costs may be useful in providing recommendations for policy and decision makers. This systematic review aimed to assess the economic burden of obesity and to identify, measure and describe the different obesity-related diseases included in the selected studies. Methods: A systematic literature search of studies in the English language was carried out in Medline (PubMed) and Web of Science databases to select cost-of-illness studies calculating the cost of obesity in a study population aged ≥18 years with obesity, as defined by a body mass index of ≥30 kg/m², for the whole selected country. The time frame for the analysis was January 2011 to September 2016. Results: The included twenty three studies reported a substantial economic burden of obesity in both developed and developing countries. There was considerable heterogeneity in methodological approaches, target populations, study time frames, and perspectives. This prevents an informative comparison between most of the studies. Specifically, there was great variety in the included obesity-related diseases and complications among the studies. Conclusions: There is an urgent need for public health measures to prevent obesity in order to save societal resources. Moreover, international consensus is required on standardized methods to calculate the cost of obesity to improve homogeneity and comparability. This aspect should also be considered when including obesity-related diseases.

KAP1 controls endogenous retroviruses in embryonic stem cells

Abstract: More than forty per cent of the mammalian genome is derived from retroelements, of which about one-quarter are endogenous retroviruses (ERVs). Some are still active, notably in mice the highly polymorphic early transposon (ETn)/MusD and intracisternal A-type particles (IAP). ERVs are transcriptionally silenced during early embryogenesis by histone and DNA methylation (and reviewed in ref. 7), although the initiators of this process, which is essential to protect genome integrity, remain largely unknown. KAP1 (KRAB-associated protein 1, also known as tripartite motif-containing protein 28, TRIM28) represses genes by recruiting the histone methyltransferase SETDB1, heterochromatin protein 1 (HP1) and the NuRD histone deacetylase complex, but few of its physiological targets are known. Two lines of evidence suggest that KAP1-mediated repression could contribute to the control of ERVs: first, KAP1 can trigger permanent gene silencing during early embryogenesis, and second, a KAP1 complex silences the retrovirus murine leukaemia virus in embryonic cells. Consistent with this hypothesis, here we show that KAP1 deletion leads to a marked upregulation of a range of ERVs, in particular IAP elements, in mouse embryonic stem (ES) cells and in early embryos. We further demonstrate that KAP1 acts synergistically with DNA methylation to silence IAP elements, and that it is enriched at the 5' untranslated region (5'UTR) of IAP genomes, where KAP1 deletion leads to the loss of histone 3 lysine 9 trimethylation (H3K9me3), a hallmark of KAP1-mediated repression. Correspondingly, IAP 5'UTR sequences can impose in cis KAP1-dependent repression on a heterologous promoter in ES cells. Our results establish that KAP1 controls endogenous retroelements during early embryonic development.