Concurrent starch accumulation in stump and high fruit production in coffee (Coffea arabica)

In coffee, fruit production on a given shoot drops after some years of high yield, triggering pruning to induce resprouting. The timing of pruning is a crucial farmer's decision affecting yield and labour. One reason for fruit production drop could be the exhaustion of resources, particularly the non-structural carbohydrates (NSC). To test this hypothesis in a Coffea L. arabica agroforestry system, we measured the concentrations of NSC, carbon (C) and nitrogen (N) in leaves, stems and stumps of the coffee plants, 2 and 5 years after pruning. We also compared shaded vs full sun plants. For that purpose, both analytical reference and visible and near infrared reflectance spectroscopy (VNIRS) methods were used. As expected, concentrations of biochemical variables linked to photosynthesis activity (N, glucose, fructose, sucrose) decreased from leaves to stems, and then to stumps. In contrast, variables linked more closely to plant structure and reserves (total C, C:N ratio, starch concentration) were higher in long lifespan organs like stumps. Shading had little effect on most measured parameters, contrary to expectations. Concentrations of N, glucose and fructose were higher in 2-year-old organs. Conversely, starch concentration in perennial stumps was three times higher 5 years after pruning than 2 years after pruning, despite high fruit production. Therefore, the drop in fruit production occurring after 5-6 years was not due to a lack of NSC on plant scale. Starch accumulation in perennial organs concurrently to other sinks, such as fruit growth, could be considered as a 'survival' strategy, which may be a relic of the behaviour of wild coffee (a tropical shade-tolerant plant). This study confirmed that VNIRS is a promisingly rapid and cost-effective option for starch monitoring (coefficient of determination for validation, R2val = 0.91), whereas predictions were less accurate for soluble sugars, probably due to their too similar spectral signature.

German Aerospace Center's advanced robotic technology for future lunar scientific missions

The Earth's moon is currently an object of interest of many space agencies for unmanned robotic missions within this decade. Besides future prospects for building lunar gateways as support to human space flight, the Moon is an attractive location for scientific purposes. Not only will its study give insight on the foundations of the Solar System but also its location, uncontaminated by the Earth's ionosphere, represents a vantage point for the observation of the Sun and planetary bodies outside the Solar System. Lunar exploration has been traditionally conducted by means of single-agent robotic assets, which is a limiting factor for the return of scientific missions. The German Aerospace Center (DLR) is developing fundamental technologies towards increased autonomy of robotic explorers to fulfil more complex mission tasks through cooperation. This paper presents an overview of past, present and future activities of DLR towards highly autonomous systems for scientific missions targeting the Moon and other planetary bodies. The heritage from the Mobile Asteroid Scout (MASCOT), developed jointly by DLR and CNES and deployed on asteroid Ryugu on 3 October 2018 from JAXA's Hayabusa2 spacecraft, inspired the development of novel core technologies towards higher efficiency in planetary exploration. Together with the lessons learnt from the ROBEX project (2012-2017), where a mobile robot autonomously deployed seismic sensors at a Moon analogue site, this experience is shaping the future steps towards more complex space missions. They include the development of a mobile rover for JAXA's Martian Moons eXploration (MMX) in 2024 as well as demonstrations of novel multi-robot technologies at a Moon analogue site on the volcano Mt Etna in the ARCHES project. Within ARCHES, a demonstration mission is planned from the 14 June to 10 July 2021,¹ during which heterogeneous teams of robots will autonomously conduct geological and mineralogical analysis experiments and deploy an array of low-frequency antennas to measure Jovian and solar bursts. This article is part of a discussion meeting issue 'Astronomy from the Moon: the next decades'.

Increased light-use efficiency sustains net primary productivity of shaded coffee plants in agroforestry system

In agroforestry systems, shade trees strongly affect the physiology of the undergrown crop. However, a major paradigm is that the reduction in absorbed photosynthetically active radiation is, to a certain extent, compensated by an increase in light-use efficiency, thereby reducing the difference in net primary productivity between shaded and non-shaded plants. Due to the large spatial heterogeneity in agroforestry systems and the lack of appropriate tools, the combined effects of such variables have seldom been analysed, even though they may help understand physiological processes underlying yield dynamics. In this study, we monitored net primary productivity, during two years, on scales ranging from individual coffee plants to the entire plot. Absorbed radiation was mapped with a 3D model (MAESPA). Light-use efficiency and net assimilation rate were derived for each coffee plant individually. We found that although irradiance was reduced by 60% below crowns of shade trees, coffee light-use efficiency increased by 50%, leaving net primary productivity fairly stable across all shade levels. Variability of aboveground net primary productivity of coffee plants was caused primarily by the age of the plants and by intraspecific competition among them (drivers usually overlooked in the agroforestry literature) rather than by the presence of shade trees.

Green jobs to meet America's biggest challenges

We confront a pivotal moment sparked by a crisis. Such times in the past have sparked important changes. Our economic and ecosystems are linked and both now demand quick attention and action. We need wise decisions that maximize job creation.

Relationship between dietary intake, antioxidant status and smoking habits in female Austrian smokers

BACKGROUND

Previous studies have shown that cigarette smoke contains many oxidants and free radicals, which can increase lipid peroxidation.

AIM OF THE STUDY

The association between smoking, food pattern, especially vitamin intake and plasma concentrations of important antioxidants, as well as lipid peroxidation products was assessed in this cross-sectional study.

SUBJECTS AND METHODS

Sixty Austrian women aged 18-40 y were enrolled in the study. Twenty-nine women were allocated to the smoking group; thirty-one women served as nonsmoking controls. Plasma concentrations of alpha- and gamma-tocopherol, alpha- and beta-carotene, lycopene, cryptoxanthin, retinol, ascorbate and malondialdehyde were determined by HPLC; dietary intake and food pattern had been assessed by four 24-h dietary intake recalls and one food frequency questionnaire.

RESULTS

Generally, food intake patterns were not different between smoking and nonsmoking women. But, a significantly higher intake of alcohol was observed in the smoking group (P < 0.05). Plasma ascorbic acid concentration of the smoking group did not differ from the nonsmoking women. Despite the increased utilization because of the oxidative stress in smokers, this result might be explained by the high dietary intake of vitamin C in our smoking group. Significantly lower plasma concentrations of alpha-,beta-carotene and lycopene have been partly ascribed to the enhanced metabolic turnover resulting from smoking-induced oxidative stress. Our results confirm that smoking had no effects on plasma tocopherol and plasma retinol concentrations.

CONCLUSIONS

The poor supply with the carotenoids alpha-, beta-carotene and lycopene may result from the increased metabolism of antioxidants caused by oxidative stress and may be responsible for significantly higher levels of lipid peroxidation products in smokers compared to nonsmokers (P < 0.05).

Nephropathia epidemica and Puumala virus in Austria

To study the epidemiology of hantavirus infections in Austria, 1215 humans and 596 rodents of different species were tested for the presence of antibodies against Puumala and Hantaan virus. Direct virus identification by polymerase chain reaction in lung tissue of serologically positive rodents was performed to verify antibody results and to determine the genetic identity of viral RNA by phylogenetic analysis of a part of the hantavirus M segment. For 32 of the 37 cases of nephropathia epidemica diagnosed in Austria, the location where transmission took place could be traced to specific areas in the Austrian federal states of Carinthia and Styria. The overall seroprevalence in humans was 1.2% and ranged from 0.02% in Villach, Carinthia, to 0.8% in Korneuburg, Lower Austria, and 1.8% in Wolfsberg, Carinthia. Virus RNA could be amplified from three Clethrionomys glareolus voles collected in Klippitztörl, Carinthia, and from one collected in Ernstbrunn, Lower Austria. The sequences were all identified as Puumala virus by phylogenetic analysis and were found to be most closely related to the western European Puumala viruses from Germany and France. No evidence of the existence of Hantaan-like infections and viruses in Austria was found.

Assembly of MHC class I molecules with biosynthesized endoplasmic reticulum-targeted peptides is inefficient in insect cells and can be enhanced by protease inhibitors

To study the requirements for assembly of MHC class I molecules with antigenic peptides in the endoplasmic reticulum (ER), we studied Ag processing in insect cells. Insects lack a class I recognition system, and their cells therefore provide a "blank slate" for identifying the proteins that have evolved to facilitate assembly of class I molecules in vertebrate cells. H-2Kb heavy chain, mouse beta 2-microglobulin, and an ER-targeted version of a peptide corresponding to Ova(257-264) were expressed in insect cells using recombinant vaccinia viruses. Cell surface expression of Kb-OVA(257-264) complexes was quantitated using a recently described complex-specific mAb (25-D1.16). Relative to TAP-deficient human cells, insect cells expressed comparable levels of native, peptide-receptive cell surface Kb molecules, but generated cell surface Kb-OVA(257-264) complexes at least 20-fold less efficiently from ER-targeted peptides. The inefficient assembly of Kb-OVA(257-264) complexes in the ER of insect cells cannot be attributed solely to a requirement for human tapasin, since first, human cells lacking tapasin expressed endogenously synthesized Kb-OVA(257-264) complexes at levels comparable to tapasin-expressing cells, and second, vaccinia virus-mediated expression of human tapasin in insect cells did not detectably enhance the expression of Kb-OVA(257-264) complexes. The assembly of Kb-OVA(257-264) complexes could be greatly enhanced in insect but not human cells by a nonproteasomal protease inhibitor. These findings indicate that insect cells lack one or more factors required for the efficient assembly of class I-peptide complexes in vertebrate cells and are consistent with the idea that the missing component acts to protect antigenic peptides or their immediate precursors from degradation.

Human peptide transporter deficiency: importance of HLA-B in the presentation of TAP-independent EBV antigens

Two siblings with a peptide TAP deficiency were recently described. Despite poor cell surface expression of HLA class I molecules, these patients were not unusually susceptible to viral infections. The majority of the cell surface-expressed class I molecules were HLA-B products as assessed by cytofluorometry and biochemical analysis. Analysis of two peptides eluted from the class I molecules expressed by TAP-deficient EBV B lymphoblastoid cell lines indicated that both were derived from cytosolic proteins and presented by HLA-B molecules. Peripheral alphabeta CD8+ T cells were present and their TCR repertoire was polyclonal. Most of the alphabeta CD8+ T cell clones studied (21 of 22) were nonreactive against cells expressing normal levels of the same HLA alleles as those of the TAP-deficient patients. However, it was possible to isolate one cytotoxic CD8+ alphabeta T cell clone recognizing the EBV protein LMP2 presented by HLA-B molecules on TAP-deficient cells. These observations suggest that in the TAP-deficient patients, CD8+ alphabeta T cells could mature and be recruited in immune responses to mediate HLA class I-restricted cytotoxic defense against viral infections. They also strengthen the physiologic importance of a TAP-independent processing pathway of the LMP2 protein, which was previously shown to contain several other TAP-independent epitopes.

Human peptide transporter deficiency: importance of HLA-B in the presentation of TAP-independent EBV antigens

Two siblings with a peptide TAP deficiency were recently described. Despite poor cell surface expression of HLA class I molecules, these patients were not unusually susceptible to viral infections. The majority of the cell surface-expressed class I molecules were HLA-B products as assessed by cytofluorometry and biochemical analysis. Analysis of two peptides eluted from the class I molecules expressed by TAP-deficient EBV B lymphoblastoid cell lines indicated that both were derived from cytosolic proteins and presented by HLA-B molecules. Peripheral alphabeta CD8+ T cells were present and their TCR repertoire was polyclonal. Most of the alphabeta CD8+ T cell clones studied (21 of 22) were nonreactive against cells expressing normal levels of the same HLA alleles as those of the TAP-deficient patients. However, it was possible to isolate one cytotoxic CD8+ alphabeta T cell clone recognizing the EBV protein LMP2 presented by HLA-B molecules on TAP-deficient cells. These observations suggest that in the TAP-deficient patients, CD8+ alphabeta T cells could mature and be recruited in immune responses to mediate HLA class I-restricted cytotoxic defense against viral infections. They also strengthen the physiologic importance of a TAP-independent processing pathway of the LMP2 protein, which was previously shown to contain several other TAP-independent epitopes.

Stimulation of renin secretion by potassium-channel activation with cromakalim

The cardiovascular and endocrine profile of cromakalim has been studied in 8 healthy men (age 25 +/- 2 years: means SEM) and its influence on renin release from cultured rat juxtaglomerular cells in vitro has also been examined. According to a double-blind, randomized sequence the subjects received placebo or cromakalim 1 mg as a single daily oral dose for 5 days. Compared to placebo, cromakalim significantly increased plasma renin activity (+ 122%; from 1.73 to 3.87 ng AI.ml-1.h-1), angiotensin II (+ 105%; from 5.1 to 10.5 pg.ml-1), and norepinephrine (+ 61%) levels, and heart rate (+ 8%). Plasma aldosterone, blood pressure and indices of the electrolyte-fluid volume state were unchanged. Cromakalim in vitro stimulated renin release, from 9.9 to 36.5 ng AI.h-1.30 min.mg cell protein, from juxtaglomerular cells. It appears that the presumed K+-channel activator cromakalim increases renin release in vivo at least in part by direct stimulation of renal juxtaglomerular cells.

II. IgM-mediated enhancement: dependency on antigen dose, T-cell requirement and lack of evidence for an idiotype-related mechanism

Passive administration of monoclonal IgM anti-sheep red blood cell antibody 2 hr prior to a low dose of sheep red blood cells (SRBC) markedly enhances the specific antibody response. This IgM enhancement of the response to SRBC is highly reproducible and can furthermore be demonstrated in vitro. The time course and dose dependency of the response indicate that a critical antibody: antigen ratio is necessary for enhancement to occur. The IgM enhancement phenomenon has been demonstrated in several strains of mice, providing strong evidence against an idiotype-related mechanism.

A pneumatic system for presenting visual stimuli

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