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The New Phytologist Jun 2024Pollination presents a risky journey for pollen grains. Pollen loss is sometimes thought to favour greater pollen investment to compensate for the inefficiency of...
Pollination presents a risky journey for pollen grains. Pollen loss is sometimes thought to favour greater pollen investment to compensate for the inefficiency of transport. Sex allocation theory, to the contrary, has consistently concluded that postdispersal loss should have no selective effect on investment in either sex function. But the intuitively appealing compensation idea continues to be raised despite the lack of theoretical endorsement. We address the theoretical issue with a model that directly represents pollen loss (and ovule loss through floral demise or loss of receptivity) as rate-dependent dynamical processes. These loss rates can be varied to examine the effect of pollination efficiency on optimal sex allocation. Pollen-ovule ratios follow from the sex allocation based on the resource costs of pollen and ovule production. This model confirms conventional findings that pollen loss should have essentially no effect on sexual resource allocation in large, panmictic populations. Pollen limitation of seed set does not alter this conclusion. These results force us to rethink the empirical association of pollination efficiency with low pollen-ovule ratios. This pattern could arise if efficient pollen transport commonly results in stigmatic deposition of cohorts of related pollen. Empirical evidence of correlated paternity supports this explanation.
PubMed: 38937955
DOI: 10.1111/nph.19929 -
Scientific Reports Jun 2024This study investigates the ecological interaction between honeybees (Apis mellifera) and fennel (Foeniculum vulgare) plants, examining the mutual benefits of this...
This study investigates the ecological interaction between honeybees (Apis mellifera) and fennel (Foeniculum vulgare) plants, examining the mutual benefits of this relationship. Field experiments conducted in Egypt from December 2022 to May 2023 recorded diverse insect pollinators attracted to fennel flowers, especially honeybees. Assessing honeybee colonies near fennel fields showed improvements in sealed brood (357.5-772.5 cells), unsealed brood (176.3-343.8 cells), pollen collection (53.25-257.5 units), honey accumulation (257.5-877.5 units), and colony strength (7.75-10) over three weeks. Fennel exposure explained 88-99% of variability in foraging metrics. Comparing open versus self-pollinated fennel revealed enhanced attributes with bee pollination, including higher flower age (25.67 vs 19.67 days), more seeds per umbel (121.3 vs 95.33), bigger seeds (6.533 vs 4.400 mm), heavier seeds (0.510 vs 0.237 g/100 seeds), and increased fruit weight per umbel (0.619 vs 0.226 g). Natural variation in seed color and shape also occurred. The outcomes demonstrate the integral role of honeybees in fennel agroecosystems through efficient pollination services that improve crop productivity and quality. Fennel provides abundant nutritional resources that bolster honeybee colony health. This research elucidates the symbiotic bee-fennel relationship, underscoring mutualistic benefits and the importance of ecological conservation for sustainable agriculture.
Topics: Bees; Animals; Foeniculum; Pollination; Flowers; Crop Production; Crops, Agricultural; Egypt; Pollen
PubMed: 38937513
DOI: 10.1038/s41598-024-64283-2 -
Nature Communications Jun 2024Flowering plants rely on the polarized growth of pollen tubes to deliver sperm cells (SCs) to the embryo sac for double fertilization. In pollen, the vegetative nucleus...
Flowering plants rely on the polarized growth of pollen tubes to deliver sperm cells (SCs) to the embryo sac for double fertilization. In pollen, the vegetative nucleus (VN) and two SCs form the male germ unit (MGU). However, the mechanism underlying directional transportation of MGU is not well understood. In this study, we provide the first full picture of the dynamic interplay among microtubules, actin filaments, and MGU during pollen germination and tube growth. Depolymerization of microtubules and inhibition of kinesin activity result in an increased velocity and magnified amplitude of VN's forward and backward movement. Pharmacological washout experiments further suggest that microtubules participate in coordinating the directional movement of MGU. In contrast, suppression of the actomyosin system leads to a reduced velocity of VN mobility but without a moving pattern change. Moreover, detailed observation shows that the direction and velocity of VN's movement are in close correlations with those of the actomyosin-driven cytoplasmic streaming surrounding VN. Therefore, we propose that while actomyosin-based cytoplasmic streaming influences on the oscillational movement of MGU, microtubules and kinesins avoid MGU drifting with the cytoplasmic streaming and act as the major regulator for fine-tuning the proper positioning and directional migration of MGU in pollen.
Topics: Microtubules; Actin Cytoskeleton; Kinesins; Pollen; Actomyosin; Pollen Tube; Cell Nucleus; Arabidopsis; Cytoplasmic Streaming; Germination
PubMed: 38937444
DOI: 10.1038/s41467-024-49323-9 -
Plant Biology (Stuttgart, Germany) Jun 2024The flower perianth has various, non-mutually exclusive functions, such as visual signalling to pollinators and protecting the reproductive organs from the elements and...
The flower perianth has various, non-mutually exclusive functions, such as visual signalling to pollinators and protecting the reproductive organs from the elements and from florivores, but how different perianth structures and their different sides play a role in these functions is unclear. Intriguingly, in many species there is a clear colour difference between the different sides of the perianth, with colour patterns or pigmentation present on only one side. Any adaptive benefit from such colour asymmetry is unclear, as is how the asymmetry evolved. In this viewpoint paper, we address the phenomenon of flowers with differently coloured inner and outer perianth sides, focusing on petals of erect flowers. Guided by existing literature and our own observations, we delineate three non-mutually exclusive evolutionary hypotheses that may explain the factors underlying differently coloured perianth sides. The pollen-protection hypothesis predicts that the outer side of petals contributes to protect pollen against UV radiation, especially during the bud stage. The herbivore-avoidance hypothesis predicts that the outer side of petals reduces the flower's visibility to herbivores. The signalling-to-pollinators hypothesis predicts that flower colours evolve to increase conspicuousness to pollinators. The pollen-protection hypothesis, the herbivore-avoidance hypothesis, and the signalling-to-pollinators hypothesis generate largely but not entirely overlapping predictions about the colour of the inner and outer side of the petals. Field and laboratory research is necessary to disentangle the main drivers and adaptive significance of inner-outer petal side colour asymmetry.
PubMed: 38935692
DOI: 10.1111/plb.13680 -
Molecular Biology and Evolution Jun 2024Segregation distorters (SDs) are genetic elements that distort the Mendelian segregation ratio to favor their own transmission and are able to spread even when they...
Segregation distorters (SDs) are genetic elements that distort the Mendelian segregation ratio to favor their own transmission and are able to spread even when they incur fitness costs on organisms carrying them. Depending on the biology of the host organisms and the genetic architecture of the SDs, the population dynamics of SDs can be highly variable. Inbreeding is considered an effective mechanism for inhibiting the spread of SDs in populations, and can evolve as a defense mechanism against SDs in some systems. However, we show that inbreeding in the form of selfing, in fact promotes the spread of SDs acting as pollen killers in a toxin-antidote system in hermaphroditic plants by two mechanisms: (1) By reducing the effective recombination rate between killer and antidote loci in two-locus systems and (2) by increasing the proportion of SD alleles in individual flowers, rather than in the general gene-pool. We also show that in rice (Oryza sativa L.), a typical hermaphroditic plant, all molecularly characterized SDs associated with pollen killing were involved in population hybridization and have introgressed across different species. Paradoxically, these loci, which are associated with hybrid incompatibility and can be thought of as Bateson-Dobzhansky-Muller incompatibility loci expected to reduce gene-flow between species, in fact cross species boundaries more frequently than random loci and may act as important drivers of introgression.
PubMed: 38935581
DOI: 10.1093/molbev/msae132 -
Expert Review of Clinical Immunology Jun 2024Administrationof allergen mixtures of many components comprises the most common approach forAmerican allergists regarding the management of polyallergic patients....
BACKGROUND
Administrationof allergen mixtures of many components comprises the most common approach forAmerican allergists regarding the management of polyallergic patients. Europeanallergists, however, are more reluctant to this type of treatment due to thepotential drawbacks of mixing extracts.
RESEARCH DESIGNAND METHODS
To assess theefficacy and safety of subcutaneous immunotherapy (SCIT) with polymerizedallergen mixtures without dilutional effect in polyallergic patients.Thisobservational, prospective, multicenter study included patients (between 5-60 years) with respiratory allergic diseases that had been prescribed with SCITwith mixtures of two pollen or mite extracts. Changesin Symptoms and Medication Score (SMS) and in rhinitis quality of life questionnaire (RQLQ), subjective clinicalimprovement, treatment satisfaction and tolerability were assessed after the1-year treatment.
RESULTS
115 patientswere included in the assessment. Mean global SMS decreased from 3.5 (SD = 1.1) to1.6 (SD = 1.2) points, with a meanabsolute reduction of 1.6 (SD = 1.3) points in the RQLQ score ( < 0.001, Wilcoxon test). General subjective clinical improvements anda good treatment satisfaction and tolerability were observed.
CONCLUSION
SCIT with polymerizedallergen mixtures from either pollen or mite extracts proved to be an effectiveand safe treatment option for polyallergic patients suffering from allergicrespiratory diseases.
PubMed: 38934292
DOI: 10.1080/1744666X.2024.2373886 -
International Journal of Urology :... Jun 2024Benign prostatic hyperplasia, a prevalent condition in aging men, is characterized by the proliferation of prostatic epithelial and stromal cells, which leads to bladder... (Review)
Review
Benign prostatic hyperplasia, a prevalent condition in aging men, is characterized by the proliferation of prostatic epithelial and stromal cells, which leads to bladder outlet obstruction and the exacerbation of lower urinary tract symptoms. There is increasing evidence that chronic prostatic inflammation contributes to the pathogenesis and progression of benign prostatic hyperplasia. This review explores the complex relationship between chronic inflammation and benign prostatic hyperplasia, focusing on the underlying mechanisms, clinical implications, and current therapeutic approaches. The pathophysiology of benign prostatic hyperplasia is multifaceted, involving factors such as hormonal changes, hypoxia, urine reflux into prostatic ducts and stroma, autoimmune responses, and infection-induced inflammation. Inflammatory cytokines, particularly interleukin-17 and interleukin-8, may play key roles in tissue remodeling and smooth muscle contraction within the prostate, thereby influencing benign prostatic hyperplasia progression. Current therapies for benign prostatic hyperplasia include α1-blockers, phosphodiesterase 5 inhibitors, 5α-reductase inhibitors, and plant-based treatments (e.g., pollen extract). These therapies aim to alleviate symptoms by reducing prostatic inflammation, improving blood flow, and inhibiting hormonal pathways involved in prostatic enlargement. However, patients with chronic prostatic inflammation often experience more severe lower urinary tract symptoms and may be resistant to conventional treatments. This resistance has prompted the exploration of alternative therapies targeting inflammation. Chronic prostatic inflammation plays a central role in the pathogenesis and severity of benign prostatic hyperplasia. An understanding of its mechanisms will enable the development of more effective treatments to improve the quality of life among patients with benign prostatic hyperplasia.
PubMed: 38934050
DOI: 10.1111/iju.15518 -
Frontiers in Immunology 2024Allergic sensitization is an essential step in the development of allergic airway inflammation to birch pollen (BP); however, this process remains to be fully...
INTRODUCTION & OBJECTIVE
Allergic sensitization is an essential step in the development of allergic airway inflammation to birch pollen (BP); however, this process remains to be fully elucidated. Recent scientific advances have highlighted the importance of the allergen context. In this regard, microbial patterns (PAMPs) present on BP have attracted increasing interest. As these PAMPs are recognized by specialized pattern recognition receptors (PRRs), this study aims at investigating the roles of intracellular PRRs and the inflammasome regulator NLRP3.
METHODS
We established a physiologically relevant intranasal and adjuvant-free sensitization procedure to study BP-induced systemic and local lung inflammation.
RESULTS
Strikingly, BP-sensitized -deficient mice showed significantly lower IgE levels, Th2-associated cytokines, cell infiltration into the lung, mucin production and epithelial thickening than their wild-type counterparts, which appears to be independent of inflammasome formation. Intriguingly, bone-marrow chimera revealed that expression of NLRP3 in the hematopoietic system is required to trigger an allergic response.
CONCLUSION
Overall, this study identifies NLRP3 as an important driver of BP-induced allergic immune responses.
Topics: Animals; NLR Family, Pyrin Domain-Containing 3 Protein; Pollen; Betula; Mice; Mice, Knockout; Administration, Intranasal; Allergens; Disease Models, Animal; Inflammasomes; Mice, Inbred C57BL; Cytokines; Hypersensitivity; Plant Extracts; Immunoglobulin E
PubMed: 38933263
DOI: 10.3389/fimmu.2024.1393819 -
Ecology and Evolution Jun 2024A new species of the extant staphylinid genus Moore & Legner, sp. nov., is reported from mid-Cretaceous Kachin amber of northern Myanmar. is distinguishable from...
A new species of the extant staphylinid genus Moore & Legner, sp. nov., is reported from mid-Cretaceous Kachin amber of northern Myanmar. is distinguishable from extant members of by the smoother dorsal surface of head, pronotum and elytra, less prominent median projection of clypeus, unnotched mesal edge of mandibles, semiglabrous antennomere 6, and longer tarsomere 1. The pollen-containing coprolite attached to the beetle and the crystals within the beetle body provide valuable information about the biology and taphonomy of the fossil.
PubMed: 38932960
DOI: 10.1002/ece3.11487 -
Vaccines Jun 2024Currently, allergen-specific immunotherapy (AIT) for ragweed allergy is still based on natural allergen extracts. This study aimed to analyse the ability of four...
Currently, allergen-specific immunotherapy (AIT) for ragweed allergy is still based on natural allergen extracts. This study aimed to analyse the ability of four commercially available AIT vaccines (CLUSTOID, TYRO-SIT, POLLINEX Quattro Plus and Diater Depot) regarding their ability to induce IgG antibodies against ragweed pollen allergens in rabbits. Accordingly, the IgG reactivity of AIT-induced rabbit sera was tested for ten different ragweed pollen allergens (Amb a 1, 3, 4, 5, 6, 8, 9, 10, 11 and 12) by an ELISA. Furthermore, the ability of rabbit AIT-specific sera to block allergic patients' IgE binding to relevant ragweed allergens (Amb a 1, 4, 6, 8 and 11) and to inhibit allergen-induced basophil activation was evaluated by an IgE inhibition ELISA and a mediator release assay. Only two AIT vaccines (Diater Depot > CLUSTOID) induced relevant IgG antibody levels to the major ragweed allergen Amb a 1. The IgG responses induced by the AIT vaccines against the other ragweed allergens were low and highly heterogeneous. Interestingly, the kinetics of IgG responses were different among the AIT vaccines and even within one AIT vaccine (Diater Depot) for Amb a 1 (long-lasting) versus Amb a 8 and Amb a 11 (short-lived). This could be due to variations in allergen contents, the immunogenicity of the allergens, and different immunization protocols. The IgE inhibition experiments showed that rabbit AIT-specific sera containing high allergen-specific IgG levels were able to inhibit patients' IgE binding and prevent the mediator release with Diater Depot. The high levels of allergen-specific IgG levels were associated with their ability to prevent the recognition of allergens by patients' IgE and allergen-induced basophil activation, indicating that the measurement of allergen-induced IgG could be a useful surrogate marker for the immunological efficacy of vaccines. Accordingly, the results of our study may be helpful for the selection of personalized AIT vaccination strategies for ragweed-allergic patients.
PubMed: 38932364
DOI: 10.3390/vaccines12060635