Elucidating climatic drivers of photosynthesis by tropical forests

Tropical forests play a pivotal role in regulating the global carbon cycle. However, the response of these forests to changes in absorbed solar energy and water supply under the changing climate is highly uncertain. Three-year (2018–2021) spaceborne high-resolution measurements of solar-induced chlorophyll fluorescence (SIF) from the TROPOspheric Monitoring Instrument (TROPOMI) provide a new opportunity to study the response of gross primary production (GPP) and more broadly tropical forest carbon dynamics to differences in climate. SIF has been shown to be a good proxy for GPP on monthly and regional scales. Combining tropical climate reanalysis records and other contemporary satellite products, we find that on the seasonal timescale, the dependence of GPP on climate variables is highly heterogeneous. Following the principal component analyses and correlation comparisons, two regimes are identified: water limited and energy limited. GPP variations over tropical Africa are more correlated with water-related factors such as vapor pressure deficit (VPD) and soil moisture, while in tropical Southeast Asia, GPP is more correlated with energy-related factors such as photosynthetically active radiation (PAR) and surface temperature. Amazonia is itself heterogeneous: with an energy-limited regime in the north and water-limited regime in the south. The correlations of GPP with climate variables are supported by other observation-based products, such as Orbiting Carbon Observatory-2 (OCO2) SIF and FluxSat GPP. In each tropical continent, the coupling between SIF and VPD increases with the mean VPD. Even on the interannual timescale, the correlation of GPP with VPD is still discernable, but the sensitivity is smaller than the intra-annual correlation. By and large, the dynamic global vegetation models in the TRENDY v8 project do not capture the high GPP seasonal sensitivity to VPD in dry tropics. The complex interactions between carbon and water cycles in the tropics illustrated in this study and the poor representation of this coupling in the current suite of vegetation models suggest that projections of future changes in carbon dynamics based on these models may not be robust.     

Working with Jewish ultra-orthodox patients: Guidelines for a culturally sensitive therapy

The epistemological gap between the medical reality of mental health practitioners and the sacred reality of their Jewish ultra-orthodox patients poses a major challenge for therapy. Based on our work with psychiatric patients from the ultraorthodox community of northern Jerusalem, we propose a set of guidelines to cope with this challenge. Basically, we seek to incorporate religiously congruent elements, composed of metaphoric images, narratives and actions, into the wide range of our secular treatment modalities in order to respond to the patient's suffering, often expressed through distinctively religious idioms of distress. This endeavor calls for a temporary suspension of disbelief on both sides.The guidelines presented include three sets of factors which appear pertinent to working with ultra-orthodox patients. The first set is contextual in nature, dealing with the image of the clinic and its physical setting; the second discusses the necessary role requisites of the therapists; and the third one, accorded a central importance, deals on various levels with the therapeutic interventions administered in terms of form and content. Several case vignettes are presented to illustrate three classes of religiously informed interventions: healing rituals, dream interpretation, and the use of culturally congruent metaphors and stories. In the concluding part we discuss ethical and instrumental issues that the proposed therapeutic guidelines may raise.     

Selection of 3LL tumor subline resistant to natural effector cells concomitantly selected for increased metastatic potency

Summary The numbers of strongly adherent monocytes in the peripheral blood of normal subjects and cancer patients were determined. The method used was to place peripheral blood mononuclear cells in microwells and culture them for 1 week. At the end of that period, adherent macrophages were counted in the Coulter counter after release. Adherent cells per milliliter of blood, per total cells, and per mononuclear cells or monocytes plated were markedly diminished in the peripheral blood mononuclear cells of 44 melanoma, 23 breast cancer, 18 lung cancer, nine colon cancer, and 27 leukemia patients. Median values were 14.8×10⁴ adherent cells per ml peripheral blood for 86 normal subjects, as against 2.5×10⁴ per ml in the peripheral blood of the 125 patients (P<0.001). There was a poor correlation between the adherent cell numbers and the peripheral blood leukocyte counts, but an excellent correlation of the different adherent cell counts with each other. The number of adherent cells in the peripheral blood varied inversely with age in the cancer patients, but not in the normal subjects (r=0.29, P<0.005). When patients under age 50 were compared to the controls, the deficiency of adherent cells was slightly more severe in patients with stage IV lung cancer than in those with stage III lung cancer. In contrast, there was no difference in the degree of deficiency between patients with stage III melanoma and no evident disease and patients with stage IV disseminated metastatic disease. The implications of these results are discussed.     

Werner syndrome protein directly binds to the AAA ATPase p97/VCP in an ATP-dependent fashion

We have previously shown that the Werner syndrome helicase, WRNp, a member of the RecQ helicase family, forms a tight molecular complex with the p97/Valosin containing protein (VCP), a member of the AAA (ATPases associated with diverse cellular activities) family of proteins. This interaction is disrupted by chemical agents that confer DNA damage, suggesting that VCP plays an important role in the signal-dependent release of WRNp from its nucleolar sequestration site. Here, we characterized the structural requirements for interactions between WRNp and VCP and for the nuclear localization of VCP. We discovered that VCP directly binds to the RQC (RecQ conserved) domain of WRNp, which is a highly conserved motif common to the RecQ helicase family. This interaction is ATP-dependent, suggesting that VCP plays a mechanistic role in releasing WRNp from the nucleolus. Immunohistochemical analysis of various VCP domains and mutated proteins expressed in vitro demonstrated that VCP may contain several hierarchical cellular localization motifs within its domain structure.     

Protective T cell immunity against malaria liver stage after vaccination with live sporozoites under chloroquine treatment

In this study we present the first systematic analysis of the immunity induced by normal Plasmodium yoelii sporozoites in mice. Immunization with sporozoites, which was conducted under chloroquine treatment to minimize the influence of blood stage parasites, induced a strong protection against a subsequent sporozoite and, to a lesser extent, against infected RBC challenges. The protection induced by this immunization protocol proved to be very effective. Induction of this protective immunity depended on the presence of liver stage parasites, as primaquine treatment concurrent with sporozoite immunization abrogated protection. Protection was not found to be mediated by the Abs elicited against pre-erythrocytic and blood stage parasites, as demonstrated by inhibition assays of sporozoite penetration or development in vitro and in vivo assays of sporozoite infectivity or blood stage parasite development. CD4(+) and CD8(+) T cells were, however, responsible for the protection through the induction of IFN-gamma and NO.     

Molecular and physiological evidence suggests the existence of a system II-like pathway of ethylene production in non-climacteric<Emphasis Type="Italic"> Citrus</Emphasis> fruit

Mature citrus fruits, which are classified as non-climacteric, evolve very low amounts of ethylene during ripening but respond to exogenous ethylene by ripening-related pigment changes and accelerated respiration. In the present study we show that young citrus fruitlets attached to the tree produce high levels of ethylene, which decrease dramatically towards maturation. Upon harvest, fruitlets exhibited a climacteric-like rise in ethylene production, preceded by induction of the genes for 1-aminocyclopropane-1-carboxylate (ACC) synthase 1 (CsACS1), ACC oxidase 1 (CsACO1) and the ethylene receptor CsERS1. This induction was advanced and augmented by exogenous ethylene or propylene, indicating an autocatalytic system II-like ethylene biosynthesis. In mature, detached fruit, very low rates of ethylene production were associated with constitutive expression of the ACC synthase 2 (CsACS2) and ethylene receptor CsETR1 genes (system I). CsACS1 gene expression was undetectable at this stage, even following ethylene or propylene treatment, and CsERS1 gene expression remained constant, indicating that no autocatalytic response had occurred. The transition from system II-like behavior of young fruitlets to system I behavior appears to be under developmental control.Abbreviations ACC 1-Aminocyclopropane-1-carboxylate - CsACS1, CsACS2 ACC synthase - CsACO1 ACC oxidase - CsERS1, CsETR1 Ethylene receptors - DAFB Days after full bloom - 1-MCP 1-Methylcyclopropene     

Helix periodicity, topology, and dynamics of membrane-associated alpha-synuclein

The protein alpha-Synuclein (aS) is a synaptic vesicle-associated regulator of synaptic strength and dopamine homeostasis with a pathological role in Parkinson's disease. The normal function of aS depends on a membrane-associated conformation that is adopted upon binding to negatively charged lipid surfaces. Previously we found that the membrane-binding domain of aS is helical and suggested that it may exhibit an unusual structural periodicity. Here we present a study of the periodicity, topology, and dynamics of detergent micelle-bound aS using paramagnetic spin labels embedded in the micelle or attached to the protein. We show that the helical region of aS completes three full turns every 11 residues, demonstrating the proposed 11/3 periodicity. We also find that the membrane-binding domain is partially buried in the micelle surface and bends toward the hydrophobic interior, but does not traverse the micelle. Deeper submersion of certain regions within the micelle, including the unique lysine-free sixth 11-residue repeat, is observed and may be functionally important. There are no long-range tertiary contacts within this domain, indicating a highly extended configuration. The backbone dynamics of the micelle-bound region are relatively uniform with a slight decrease in flexibility observed toward the C-terminal end. These results clarify the topological features of aS bound to membrane-mimicking detergent micelles, with implications for aS function and pathology.     

Expression and importance of matrix metalloproteinase 2 and 9 (MMP-2 and -9) in human trophoblast invasion

Background  

The aim of this study was to examine the invasiveness of first trimester trophoblasts according to the secretion profile of MMP-2 and -9 at different gestational stages, and to test the similarity between primary trophoblast cell-culture and the JAR choriocarcinoma cell-line.