Plant Rabs and the role in fruit ripening

Fruit ripening is a complex developmental process that involves the synthesis and modification of the cell wall leading up to the formation of an edible fruit. During the period of fruit ripening, new cell wall polymers and enzymes are synthesized and trafficked to the apoplast. Vesicle trafficking has been shown to play a key role in facilitating the synthesis and modification of cell walls in fruits. Through reverse genetics and gene expression studies, the importance of Rab guanosine triphosphatases (GTPases) as integral regulators of vesicle trafficking to the cell wall has been revealed. It has been a decade since a rich literature on the involvement of Rab GTPase in ripening was published. Therefore, this review sets out to summarize the progress in studies on the pivotal roles of Rab GTPases in fruit development and sheds light on new approaches that could be adopted in the fields of postharvest biology and fruit-ripening research.     

The role of silk in courtship and chemical communication of the false widow spider, <Emphasis Type="Italic">Steatoda grossa</Emphasis> (Araneae: Theridiidae)

In spiders, sex pheromones are often associated with silk produced by females, and function in mate attraction, recognition, and evaluation. Silk-bound pheromones typically elicit courtship behaviour in web-building spiders. Here we (1) describe courtship interactions of Steatoda grossa males with virgin or mated females, and (2) show that silk and methanol extracts of silk produced by virgin females trigger courtship behaviour (silk production) by males, whereas silk of mated females does not. Our results indicate that (1) virgin females produce a silk-bound sex pheromone, (2) males discriminate between virgin and mated females based on silk cues, and (3) male silk likely functions in sexual communication.     

Node self‐connections and metapopulation persistence: reply to Saura (2018)

Saura ( 2018 ) claims that studies using the Probability of Connectivity metric (PC) had already demonstrated the importance of including node self‐connections in network metrics. As originally defined and used, PC cannot test the importance of self‐connections. However, with key terms redefined, PC could be a useful tool in future work.     

Integrative conservation genetics: Prioritizing populations using climate predictions,adaptive potential and habitat connectivity

Conservation decisions often involve allocation of scarce resources among many areas of need. Various approaches exist to help prioritize species and populations for conservation. Past efforts have often used relatively narrow, one‐dimensional criteria, such as genetic resource value or exposure to threats. What is lacking is a refined, comprehensive prioritization approach including ecological and evolutionary aspects, informed by rich and reliable data. In this issue of Molecular Ecology Resources, Razgour et al. ( 2017 ) present a new prioritization framework that coherently integrates three dimensions of population vulnerability: exposure to change, sensitivity to change and range shift potential. They measure these dimensions for 10 populations of a European bat using a suite of advanced analysis methods that leverage genomic, environmental and occurrence data. Explicitly recognizing and quantifying the multidimensional nature of conservation priorities is a key advance because it enables a nuanced assessment of each population and identification of populations of high concern along all three dimensions. With some caveats and modifications, this framework could be a major step for conservation prioritization and intervention that is proactive and informed by evolutionary principles.     

Functional macronutritional generalism in a large omnivore,the brown bear

We combine a recently developed framework for describing dietary generalism with compositional data analysis to examine patterns of omnivory in a large widely distributed mammal. Using the brown bear (Ursus arctos) as a model species, we collected and analyzed data from the literature to estimate the proportions of macronutrients (protein, carbohydrate, and lipid) in the diets of bear populations. Across their range, bears consumed a diversity of foods that resulted in annual population diets that varied in macronutrient proportions, suggesting a wide fundamental macronutrient niche. The variance matrix of pairwise macronutrient log‐ratios indicated that the most variable macronutrient among diets was carbohydrate, while protein and lipid were more proportional or codependent (i.e., relatively more constant log‐ratios). Populations that consumed anthropogenic foods, such agricultural crops and supplementary feed (e.g., corn), had a higher geometric mean proportion of carbohydrate, and lower proportion of protein, in annual diets. Seasonally, mean diets were lower in protein and higher in carbohydrate, during autumn compared to spring. Populations with anthropogenic subsidies, however, had higher mean proportions of carbohydrate and lower protein, across seasons compared to populations with natural diets. Proportions of macronutrients similar to those selected in experiments by captive brown bears, and which optimized primarily fat mass gain, were observed among hyperphagic prehibernation autumn diets. However, the majority of these were from populations consuming anthropogenic foods, while diets of natural populations were more variable and typically higher in protein. Some anthropogenic diets were close to the proportions selected by captive bears during summer. Our results suggest that omnivory in brown bears is a functional adaptation enabling them to occupy a diverse range of habitats and tolerate variation in the nutritional composition and availability of food resources. Furthermore, we show that populations consuming human‐sourced foods have different dietary macronutrient proportions relative to populations with natural diets.     

Characterization of induced resistance in tomato plants

We have characterized, using several types of bioassays, the resistance induced in young tomato plants by feeding of the corn earworm, Helicoverpa zea. Beet armyworm larvae, Spodoptera exigua, and leafminers, Liriomyza trifolii, were used to assay the induced resistance. In whole-plant experiments, damage localized to a single leaflet of fourleaf tomato plants induced a systemic increase in resistance such that beet armyworm larvae confined to previously damaged (induced) plants grew at a rate about half that of larvae raised on control plants and consumed less leaf tissue from induced plants than from control plants. In experiments using excised leaves, beet armyworm larvae suffered increased mortality when reared on leaves from induced plants. The strength of this induced resistance varied spatially relative to the damaged position; moreover, the spatial distribution of induced resistance changed over a three-week period following damage. Other experiments demonstrated that the mechanisms of induced resistance in tomato foliage involves both a decrease in larval preference for and a decrease in the nutritional value of induced foliage. Induction also retarded the oviposition and/or early development of leafminers. Thus, induced resistance has relatively severe effects on the biology of subsequent herbivores. These data should allow us to begin to elucidate cause-effect relationships between induced resistance and induced chemistry in tomato plants.     

Isolation and Characterization of Two Fatty Acid Binding Proteins from Mouse Brain

Abstract: Two fatty acid binding proteins (FABPs) were isolated from Swiss Webster mouse brains. Neither protein cross-reacted with antisera to recombinant liver L-FABP. One protein, designated brain H-FABP, migrated on tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) as a single band at 14.5 kDa with pl 4.9. Brain H-FABP bound NBD-stearic acid and cis -parinaric acid with K _D values near 0.02 and 0.5 µ M , respectively. Brain H-FABP cross-reacted with affinity-purified antisera to recombinant heart H-FABP. The second protein, mouse brain B-FABP, migrated on tricine SDS-PAGE gels as a doublet at 16.0 and 15.5 kDa with pl values of 4.5 and 4.7, respectively. Brain B-FABP bound NBD-stearic acid and cis -parinaric acid with K _D values near 0.01 and 0.7 µ M , respectively. The brain B-FABP doublet was immunoreactive with affinity-purified antibodies against recombinant mouse brain B-FABP, but not with affinity-purified antibodies against heart H-FABP. [³H]Oleate competition binding indicated that the two brain FABPs had distinct ligand binding specificities. Both bound fatty acids, fatty acyl CoA, and lysophosphatidic acid. Although both preferentially bound unsaturated fatty acids, twofold differences in specific saturated fatty acid binding were observed. Brain B-FABP and brain H-FABP represented 0.1 and 0.01% of brain total cytosolic protein, respectively. In summary, mouse brain contains two native fatty acid binding proteins, brain H-FABP and brain B-FABP.