Heat stress and sexual reproduction in maize: unveiling the most pivotal factors and the biggest opportunities.

The escalation in the intensity, frequency, and duration of high temperature (HT) stress is currently unparalleled, which aggravates the challenges for crop production. Yet, the stage-dependent responses of sexual reproductive organs to HT stress at the morphological, physiological, and molecular levels, remain inadequately explored, particularly in pivotal staple crops. This review synthesized current knowledge regarding the mechanisms by which HT stress induces abnormalities and aberrations in reproductive growth and development, as well as alters the morphology and function of florets and their constituents, flowering patterns, and the processes of pollination and fertilization in maize (Zea mays L.). We identified the stage-specific sensitivities to HT stress through compiling and analyzing hundreds of lines of evidence, and accurately defined the sensitive period from days to hours timescale. The microspore tetrad phase of pollen development and anthesis (especially shortly after pollination) are most sensitive to HT stress, and even brief temperature spikes during these stages can lead to significant kernel loss. Unfortunately, these weak links are hidden and often neglected in practice. The impetuses behind the heat-induced impairments in seed set are closely related to carbon, reactive oxygen species, phytohormone signals, ion (e.g., Ca2+) homeostasis, plasma membrane structure and function, and others. At last, the recent advancements in understanding the genetic mechanisms underlying HT stress responses during maize sexual reproduction have been systematically summarized. This knowledge holds significant implications for the development of improved maize genotypes and effective crop management strategies to mitigate heat stress.

From the floret to the canopy: High temperature tolerance during flowering.

Heat waves induced by climate warming have become common in food-producing regions worldwide, frequently coinciding with high temperature (HT)-sensitive stages of many crops and thus threatening global food security. Understanding the HT sensitivity of reproductive organs is currently of great interest for increasing seed set. The responses of seed set to HT involve multiple processes in both male and female reproductive organs, but we currently lack an integrated and systematic summary of these responses for the world's three leading food crops (rice, wheat, and maize). In the present work, we define the critical high temperature thresholds for seed set in rice (37.2°C ± 0.2°C), wheat (27.3°C ± 0.5°C), and maize (37.9°C ± 0.4°C) during flowering. We assess the HT sensitivity of these three cereals from the microspore stage to the lag period, including effects of HT on flowering dynamics, floret growth and development, pollination, and fertilization. Our review synthesizes existing knowledge about the effects of HT stress on spikelet opening, anther dehiscence, pollen shedding number, pollen viability, pistil and stigma function, pollen germination on the stigma, and pollen tube elongation. HT-induced spikelet closure and arrest of pollen tube elongation have a catastrophic effect on pollination and fertilization in maize. Rice benefits from pollination under HT stress owing to bottom anther dehiscence and cleistogamy. Cleistogamy and secondary spikelet opening increase the probability of pollination success in wheat under HT stress. However, cereal crops themselves also have protective measures under HT stress. Lower canopy/tissue temperatures compared with air temperatures indicate that cereal crops, especially rice, can partly protect themselves from heat damage. In maize, husk leaves reduce inner ear temperature by about 5°C compared with outer ear temperature, thereby protecting the later phases of pollen tube growth and fertilization processes. These findings have important implications for accurate modeling, optimized crop management, and breeding of new varieties to cope with HT stress in the most important staple crops.

A local model based on environmental variables clustering for estimating foliar phosphorus of rubber trees with vis-NIR spectroscopic data.

Existing local models based on multiple environmental variables clustering (LM-MEVC) treat the influences of environmental factors on leaf phosphorus concentration (LPC) of rubber trees (Hevea brasiliensis) equally when grouping samples. In fact, the effects that environmental factors assert on LPC are different. So, environmental factors need to be treated differently so that the different effects can be taken into consideration when dividing samples into clusters or groups. According to this basic idea, a local model based on weighted environmental variables clustering (LM-WEVC) was developed. This approach consists of four steps. Firstly, the most important environmental variables that influence LPC were selected. Then, the weights of the selected environmental variables were determined. In the following, the selected environmental variables were weighted and used as clustering variables to group samples. Finally, within each cluster or group of samples, an estimation model was established. In order to verify its effectiveness in predicting LPC of rubber trees, the proposed method was applied to a case study in Hainan Island, China. Rubber tree (cultivar CATAS-7-33-97) leaf samples were collected from three different sampling periods. Spectral reflectance of the collected leaf samples was measured using an ASD spectroradiometer, FieldSpec 3. Leaf samples collected from the three different sampling periods were used separately to test LM-WEVC. Coefficient of determination (R2), root mean squared error (RMSE), and ratio of prediction deviation (RPD) were employed as evaluation criterion. Performance of LM-WEVC was compared with that of the existing LM-MEVC. Results indicated that for the three sampling periods, the prediction accuracies of LM-WEVC were always higher than those of LM-MEVC. The values of R2 and RPD for LM-WEVC were increased by 8.15%-36.68%, and by 11.33%-59.40% respectively, while values of RMSE were reduced by 9.09%-37.5%, compared with those for LM-MEVC. These results demonstrate that LM-WEVC was effective in estimating LPC of rubber trees, and also confirmed our hypothesis that environmental factors unequally influenced LPC of rubber trees.

Identification of miR-4510 as a metastasis suppressor of gastric cancer through regulation of tumor microenvironment via targeting GPC3.

The genes miR-4510 and glypican-3 (GPC3) have reported to be closely associated with tumors, with miR-4510 inversely correlated with GPC3 mRNA and protein in hepatocellular carcinoma samples. Glypican-3-expressing gastric cancer (GPC3-GC), characterized as gastric cancer (GC) expressing GPC3, accounts for 11% of the GC cases. However, the expression and mechanism of action of miR-4510 in GPC3-GC have not been clearly defined. We found that miR-4510 expression in GC tissues was significantly lower than that in the adjacent tissues (p < 0.001). miRNA-4510 expression in GPC3-GC was significantly lower than that in GPC3-negative GC tissue (p < 0.001). Our study confirmed that miR-4510 is inversely correlated with GPC3 in gastric cancer samples and that GPC3 is a direct target gene of miR-4510. The proportion of M2 macrophages in GC with low expression of miR-4510 was significantly increased, while the proliferation of CD8+ T cells was limited. miR-4510 may change the immunosuppressive signals in the tumor microenvironment by downregulating GPC3 and inhibiting gastric cancer cell metastasis. Oxaliplatin treatment may become a specific therapeutic drug for patients with miR-4510 inhibition and GPC3-GC.

The Tumor-Associated Macrophage-M2-Cancer Cell Complex and the Observation of Heterogeneous Modification of the Morphological Structure of Lung Adenocarcinoma.

OBJECTIVE: The aim of this study was to investigate the effect of the tumor-associated macrophage-m2-cancer cell complex (TAM-M2-CC) on the heterostructural modification of lung adenocarcinoma. METHODS: The expression of CD163+/CD68+ in macrophages in the microenvironment of 161 cases of lung adenocarcinoma was identified by dual immunohistochemistry, and the association between a TAM-M2-CC and its growth, as well as the histological changes in lung adenocarcinoma cells, was assessed. RESULTS: The morphological change of lung adenocarcinoma was related to the number of m2 phenotypes of the macrophages in the microenvironment of lung adenocarcinoma. TAM-M2-CCs were involved in the process of cancer cell recognition, association, and reconstruction. CONCLUSION: The microenvironment of lung adenocarcinoma can affect the phenotypic distinction of macrophages, and the polarization recruitment, zombification, and formation of a TAM-M2-CC, which can also affect the local differentiation of lung adenocarcinoma to a certain extent. The applicable pathogenesis needs to be verified and studied further.

Identification, Characterization and Expression Analysis of TRP Channel Genes in the Vegetable Pest, Pieris rapae.

Transient receptor potential (TRP) channels are critical for insects to detect environmental stimuli and regulate homeostasis. Moreover, this superfamily has become potential molecular targets for insecticides or repellents. Pieris rapae is one of the most common and widely spread pests of Brassicaceae plants. Therefore, it is necessary to study TRP channels (TRPs) in P. rapae. In this study, we identified 14 TRPs in P. rapae, including two Water witch (Wtrw) genes. By contrast, only one Wtrw gene exists in Drosophila and functions in hygrosensation. We also found splice isoforms of Pyrexia (Pyx), TRPgamma (TRPγ) and TRP-Melastatin (TRPM). These three genes are related to temperature and gravity sensation, fine motor control, homeostasis regulation of Mg2+ and Zn2+ in Drosophila, respectively. Evolutionary analysis showed that the TRPs of P. rapae were well clustered into their own subfamilies. Real-time quantitative PCR (qPCR) showed that PrTRPs were widely distributed in the external sensory organs, including antennae, mouthparts, legs, wings and in the internal physiological organs, including brains, fat bodies, guts, Malpighian tubules, ovaries, as well as testis. Our study established a solid foundation for functional studies of TRP channels in P. rapae, and would be benefit to developing new approaches to control P. rapae targeting these important ion channels.

Molecular cloning and characterization of TRPVs in two rice pests: Nilaparvata lugens (Stål) and Nephotettix cincticeps (Uhler).

BACKGROUD: Insect TRPV is a subfamily of transient receptor potential (TRP) ion channels, including two genes, nanchung and inactive. It has recently been found that two commercial insecticides, pymetrozine and pyrifluquinazon, target the heteromeric TRPV ion channel complex which is specifically expressed in the chordotonal organ neurons in Drosophila. However, information on the TRPV genes in agricultural insects is still limited. RESULTS: In this study, we cloned and characterized two TRPV genes from Nilaparvata lugens (NlNan and NLIav) and Nephotettix cincticeps (NcNan and NcIav), two serious rice pests throughout Asia. The deduced amino acid sequences share highly identity with other insect homologues (58-85%) and have the characteristic TRPV domain architecture: five ankyrin repeats and six transmembrane domains. These TRPV transcripts were expressed in all developmental stages and expression levels in male adults were significantly higher than in female adults. Moreover, expression levels in antennae were much higher than in heads and legs. CONCLUSION: NlNan, NlIav, NcNan and NcIav may have roles in male-specific behaviors, and the sequence information lays the foundation for further study on the structural and functional characterization of TRPVs in agricultural pests. © 2018 Society of Chemical Industry.

A new Drosophila octopamine receptor responds to serotonin.

As the counterparts of the vertebrate adrenergic transmitters, octopamine and tyramine are important physiological regulators in invertebrates. They control and modulate many physiological and behavioral functions in insects. In this study, we reported the pharmacological properties of a new α2-adrenergic-like octopamine receptor (CG18208) from Drosophila melanogaster, named DmOctα2R. This new receptor gene encodes two transcripts by alternative splicing. The long isoform DmOctα2R-L differs from the short isoform DmOctα2R-S by the presence of an additional 29 amino acids within the third intracellular loop. When heterologously expressed in mammalian cell lines, both receptors were activated by octopamine, tyramine, epinephrine and norepinephrine, resulting in the inhibition of cAMP production in a dose-dependent manner. The long form is more sensitive to the above ligands than the short form. The adrenergic agonists naphazoline, tolazoline and clonidine can stimulate DmOctα2R as full agonists. Surprisingly, serotonin and serotoninergic agonists can also activate DmOctα2R. Several tested adrenergic antagonists and serotonin antagonists blocked the action of octopamine or serotonin on DmOctα2R. The data presented here reported an adrenergic-like G protein-coupled receptor activated by serotonin, suggesting that the neurotransmission and neuromodulation in the nervous system could be more complex than previously thought.

[The value of thoracoscopy for diagnosis and management of refractory hepatic hydrothorax].

OBJECTIVE: To study the value of thoracoscopy for diagnosis and management of refractory hepatic hydrothorax (HH). METHODS: Twenty-six patients with refractory HH were enrolled in this study. Twenty-four of them underwent therapeutic thoracoscopy to achieve pleurodesis by application of talc poudrage. RESULTS: Nineteen of the 26 patients had dilated chest wall veins, 6 had dilated azygos veins, and 16 had diaphragm blebs. Of the 24 patients who received pleurodesis via thoracoscope, 14 cases showed complete response, and 8 showed partial response. Mild chest pain and temperature elevation were the most complaints during or after the procedure. Liver function abnormalities were the most serious side effects after pleurodesis. During the follow-up period ranging from 6 months to 3 years, 1 patient died of upper gastrointestinal hemorrhage and encephalopathy in 1 month, 3 patients died of hemorrhage in 6, 12, 18 months respectively, and 1 case experienced recurrence in 18 months. CONCLUSIONS: Defects in the diaphragm seemed to be the main cause for the development of HH. Pleurodesis achieved by thoracoscopy and talc poudrage was effective in the treatment of HH, but complications and impaired liver functions should be considered.

[The relationship between transforming growth factor-beta1, platelet derived growth factor and airway remodeling in eosinophilic bronchitis].

OBJECTIVE: To study the relationship between the expression of transforming growth factor-beta(1) (TGF-beta(1)) and platelet derived growth factor (PDGF) and airway remodeling in eosinophilic bronchitis (EB). METHODS: Bronchial biopsy specimens were obtained from 12 patients with EB (A group), 10 asthmatic patients (B group) and 10 patients (C group) with peripheral lung cancer in early stage. The subepithelial basement membrane (SBM) thickness was measured by light microscopy using HE staining. The expressions of TGF-beta(1) and PDGF in the bronchial mucosa were examined by immunostaining. RESULTS: The SBM of A group [(6.3 +/- 1.4) micro m] was significantly thicker than that of C group [(4.1 +/- 1.2) micro m, P < 0.05], but significantly thinner than that of B group [(8.2 +/- 1.5) micro m]. The numbers of positive cells for TGF-beta(1) and PDGF in A group (59 +/- 9, 47 +/- 7 respectively) and B group (85 +/- 12, 76 +/- 11, respectively) were significantly higher than those in C group (31 +/- 4, 20 +/- 3, respectively), and were positively correlated with SBM thickness (r = 0.76, 0.52, P < 0.05). CONCLUSION: These results suggest that TGF-beta(1) and PDGF expressions in bronchial mucosa may play a role in bronchial subepithelial fibrosis in EB patients.