Plant secondary metabolites (SMs) acting as defensive chemicals in reproductive organs such as fruit tissues play roles in both mutualistic and antagonistic interactions between plants and seed dispersers/predators. The directed-deterrence hypothesis states that SMs in ripe fruits deter seed predators but have little or no effect on seed dispersers. Indeed, studies have demonstrated that birds are able to cope with fruit SMs whereas rodents are deterred by them. However, this mechanism was only demonstrated at the class level, i.e., between birds and mammals, based on differences in the vanilloid receptors. Here we present experimental and behavioral data demonstrating the use of the broad-range, class-independent "mustard oil bomb" mechanism in Ochradenus baccatus fruits to force a behavioral change at an ecological timescale, converting rodents from seed predators to seed dispersers. This is achieved by a unique compartmentalization of the mustard oil bomb, causing activation of the system only upon seed and pulp coconsumption, encouraging seed dispersal via seed spitting by rodents. Our findings demonstrate the power of SMs to shift the animal-plant relationship from predation to mutualism and provide support for the directed-deterrence hypothesis at the intraspecific level, in addition to the interspecific level.

Background:The phycobilisome is assembled from many subunits, but the entire structure has not been determined. Results: Coupled cross-linking/MS revealed neighboring residues within the interfaces between subunits. Conclusion: The rods completely cover the core cylinders and are not in a staggered assembly form. Significance: Energy transfer from rods to cores overcomes a jump of over 30 Å without loss of efficiency.

The COP9 signalosome (CSN) is a conserved eukaryotic complex, essential for vitality in all multicellular organisms and critical for the turnover of key cellular proteins through catalytic and non‐catalytic activities. Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of the CSN complex, since it includes a conserved enzymatic core but lacks non‐catalytic activities, probably explaining its non‐essentiality for life. A previous transcriptomic analysis of an S. cerevisiae strain deleted in the CSN5/RRI1 gene, encoding to the CSN catalytic subunit, revealed a downregulation of genes involved in lipid metabolism. We now show that the S. cerevisiae CSN holocomplex is essential for cellular lipid homeostasis. Defects in CSN assembly or activity lead to decreased quantities of ergosterol and unsaturated fatty acids (UFA); vacuole defects; diminished lipid droplets (LDs) size; and to accumulation of endoplasmic reticulum (ER) stress. The molecular mechanism behind these findings depends on CSN involvement in upregulating mRNA expression of SPT23. Spt23 is a novel activator of lipid desaturation and ergosterol biosynthesis. Our data reveal for the first time a functional link between the CSN holocomplex and Spt23. Moreover, CSN‐dependent upregulation of SPT23 transcription is necessary for the fine‐tuning of lipid homeostasis and for cellular health.

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Atherosclerosis and cardiovascular complications are prevalent among patients undergoing chronic hemodialysis (HD). In this population, peripheral polymorphonuclear leukocytes (PMNLs) are primed, releasing proinflammatory mediators such as elastase. Elastase is normally inhibited by a specific inhibitor, avoiding undesirable degradation of cellular and extracellular components. This study tested the hypothesis that in states of noninfectious inflammation, elastase is released by PMNLs and acts in an uncontrolled manner to inflict vascular damage. Blood was collected from patients undergoing HD and healthy controls (HC). PMNL intracellular and surface expressions of elastase were determined by quantitative real-time PCR, Western blotting, and flow cytometry. The elastase activity was evaluated using a fluorescent substrate. The levels of serum α-antitrypsin (α-AT), the natural elastase inhibitor, were determined by Western blot. Free active elastase was elevated in HD sera, whereas the levels of α-AT were decreased compared with HC. The levels of the intracellular elastase enzyme and its activity were lower in HD PMNLs despite similar expression levels of elastase mRNA. Elastase binding to PMNL cell surface was higher in HD compared with HC. The increased circulating levels of free active elastase released from primed HD PMNLs together with the higher cell surface-bound enzymes and the lower levels of α-AT result in the higher elastase activity in HD sera. This exacerbated elastase activity could lead to the endothelial dysfunction, as hypothesized. In addition, it suggests that free circulating elastase can serve as a new biomarker and therapeutic target to reduce inflammation and vascular complications in patients on hemodialysis.

Ochradenus baccatus is a widely distributed shrub in desert regions of the Middle East and North Africa. This plant's nematicidal activity against the root‐knot nematode Meloidogyne javanica was evaluated because it has been found to contain exceptionally high levels of glucosinolates. In in vitro assays with aqueous extracts of the plant, 100% of second‐stage juveniles were immobilized after exposure to 4% root‐core extract for 48 h; 8% root‐core extract suppressed their hatching by 87%, whereas stem, flower and root bark showed lower activity. Incorporation of root core or bark into the soil, as fresh or dry powder at 1 and 0·5% (w/w), respectively, reduced the number of nematodes recovered from the soil by 95–100%, whereas the flower and stem were much less effective. Results from further pot experiments indicated that only the root bark consistently contains nematicidal compounds which are effective in soil, whereas the nematicidal activity of the root core in soil was inconsistent. The presence of non‐volatile lipophilic and lipophobic nematicidal compounds in the root bark was suggested by extraction with different polar solvents, but these compounds do not seem to be isothiocyanates – glucosinolate‐hydrolysed compounds with nematicidal activity. Very poor host status of Ochradenus baccatus to M. javanica, M. incognita and M. hapla, but with root‐penetration rates of juveniles similar to those in tomato roots, suggest that this plant may be used as a cover plant or trap plant to reduce nematode populations in the soil.

1. The nutritious pulp of fleshy fruits facilitates seed dispersal via endozoochory.Frugivores are considered legitimate seed dispersers when they digest only the pulp but do not damage the seeds. Nevertheless, fruit pulp, in contrast to seeds, is low in nitrogen, thus potentially stimulating seed digestion in the fruit consumers, therefore raising a potential conflict of interest between the plant and the fruit consumer. 2. Pycnonotus xanthopygos is an important distributor of seeds of the desert shrub, Ochradenus baccatus. Our study demonstrated that P. xanthopygos consumed fewer O. baccatus fruits compared with Musa acuminata, due to the presence of bioactive substances O. baccatus pulp juice. 3. The passage of the O. baccatus seeds through the digestive system of P. xanthopygos resulted in damage of up to 80% of the seeds and 20% decrease in the weight of the defecated seeds.4. Despite the damage to the seeds, passage through the digestive system of P.xanthopygos significantly increased the germination of the surviving seeds. Pulp juice and/or drying of the fruits (on the shrub or in the laboratory) reduced seed germination, and separation of seeds from the pulp (manually or by the bird's digestive system) significantly increased germination. 5. Our study demonstrated variable reduced digestibility of seeds and pulp when P. xanthopygos consumed O. baccatus fruits compared with M. acuminata. This effect was correlated with inhibition of digestive enzymes in O. baccatus fruits.6. Synthesis. Our results show that there is a complex interaction between Ochradenus baccatus and Pycnonotus xanthopygos where consumption of the fruits is both beneficial and harmful to the plant, due to seed damage on the one hand, yet promotion of seed germination on the other. This suggests that frugivory in general may benefit seed distributors and seed predators simultaneously, yet also highlights a potential conflict of interest inherent in endozoochory.

In contrast to most other plant tissues, fleshy fruits are meant to be eaten in order to facilitate seed dispersal. Although fleshy fruits attract consumers, they may also contain toxic secondary metabolites. However, studies that link the effect of fruit toxins with seed dispersal and predation are scarce. Glucosinolates (GLSs) are a family of bitter-tasting compounds. The fleshy fruit pulp of Ochradenus baccatus was previously found to harbor high concentrations of GLSs, whereas the myrosinase enzyme, which breaks down GLSs to produce foul tasting chemicals, was found only in the seeds. Here we show the differential behavioral and physiological responses of three rodent species to high dose (80%) Ochradenus’ fruits diets. Acomys russatus, a predator of Ochradenus’ seeds, was the least sensitive to the taste of the fruit and the only rodent to exhibit taste-related physiological adaptations to deal with the fruits’ toxins. In contrast, Acomys cahirinus, an Ochradenus seed disperser, was more sensitive to a diet containing the hydrolyzed products of the GLSs. A third rodent (Mus musculus) was deterred from Ochradenus fruits consumption by the GLSs and their hydrolyzed products. We were able to alter M. musculus avoidance of whole fruit consumption by soaking Ochradenus fruits in a water solution containing 1% adenosine monophosphate, which blocks the bitter taste receptor in mice. The observed differential responses of these three rodent species may be due to evolutionary pressures that have enhanced or reduced their sensitivity to the taste of GLSs.