Neurogenesis dynamics in the olfactory bulb:deciphering circuitry organization, function, and adaptive plasticity

Adult neurogenesis persists after birth in the subventricular zone, with new neurons migrating to the granule cell layer and glomerular layers of the olfactory bulb, where they integrate into existing circuitry as inhibitory interneurons. The generation of these new neurons in the olfactory bulb supports both structural and functional plasticity, aiding in circuit remodeling triggered by memory and learning processes. However, the presence of these neurons, coupled with the cellular diversity within the olfactory bulb, presents an ongoing challenge in understanding its network organization and function. Moreover,the continuous integration of new neurons in the olfactory bulb plays a pivotal role in regulating olfactory information processing. This adaptive process responds to changes in epithelial composition and contributes to the formation of olfactory memories by modulating cellular connectivity within the olfactory bulb and interacting intricately with higher-order brain regions. The role of adult neurogenesis in olfactory bulb functions remains a topic of debate. Nevertheless, the functionality of the olfactory bulb is intricately linked to the organization of granule cells around mitral and tufted cells. This organizational pattern significantly impacts output, network behavior, and synaptic plasticity, which are crucial for olfactory perception and memory. Additionally, this organization is further shaped by axon terminals originating from cortical and subcortical regions. Despite the crucial role of olfactory bulb in brain functions and behaviors related to olfaction, these complex and highly interconnected processes have not been comprehensively studied as a whole. Therefore, this manuscript aims to discuss our current understanding and explore how neural plasticity and olfactory neurogenesis contribute to enhancing the adaptability of the olfactory system. These mechanisms are thought to support olfactory learning and memory, potentially through increased complexity and restructuring of neural network structures, as well as the addition of new granule granule cells that aid in olfactory adaptation. Additionally, the manuscript underscores the importance of employing precise methodologies to elucidate the specific roles of adult neurogenesis amidst conflicting data and varying experimental paradigms. Understanding these processes is essential for gaining insights into the complexities of olfactory function and behavior.

The Role of Jasmonates as Antibulbing Substances in the Bulb Formation of Onion

Onion plants form spherical bulbs under long-day conditions.Substances regulating bulb formation remain unknown.In the course of chemical studies on the bulb formation,α-linolenic acid was isolated from onion extracts as an antibulbing substance,the amount of which was synchronized with the bulb formation.Since allene oxide synthase inhibitor canceled the antibulbing activity ofα-linolenic acid,it was disclosed that jasmonic acid concerns this regulation.Structure-activity-relationship study revealed that its(3R,7S)stereochemistry is necessary for showing its antibulbing activity.It is concluded that(3R,7S)-jasmonate derived fromα-linolenic acid actually participates in the regulation of bulb formation.

CFRP布对先张法预应力Bulb-T梁抗弯性能影响研究

为研究碳纤维增强复合材料(CFRP)布对先张法预应力Bulb-T梁抗弯性能的影响,采用有限元软件ABAQUS建立了三维实体模型,并进行了四点弯曲试验数值模拟,分析了在不同CFRP布加固方式下Bulb-T梁损伤过程及受力性能。结果表明:先张法预应力Bulb-T梁模拟值与试验结果误差较小,建立的模型可以较准确地模拟足尺预应力钢混梁的破坏形态、预拱度、荷载-位移曲线;CFRP加固能够显著提升梁体的抗弯刚度及开裂荷载,延缓开裂时间、抑制裂缝的扩展,其中,下翼缘板底部粘贴CFRP布可在失效前对跨中裂缝密集区起到有效控制,弯剪区包裹加固减小了梁体加载点及垫块之间“八”字形裂缝的展开;下翼缘板底部粘贴CFRP布对抗弯承载力的提升效果更加显著,且极限承载力和刚度随着加固层数的增加而增大。

The Chemical Constituents from the Bulbs of Ornithogalum caudatum

A new natural product (1) together with 26 know compounds were isolated from the Bulbs of Ornithogalum caudatum. Their structures were established on the basis of spectral analyses as n-butyl pyroglutamate (1), nonadecyl alcohol(2), eicosanol(3), behenic acid(4), b-sitosterol(5), stigmasterol(6), glycerol 1-monocerotate(7), pyrocatechol(8), p-ethoxybenzoic acid(9), p-coumarinic acid(10), protocatechuric acid(11), ursolic acid(12), betulinic acid(13), fumaric acid(14), succinic acid(15), uracil(16), xanthine(17), quercetin(18), kaempferol (19), isorham-netin(20), adenosine(21), daucosterol(22), stigmasterol 3-O-b-D-glucopyranoside(23), quercetin 3-O-b-D-glucopyra-noside(24), kaempferol 3-O-b-D-glucopyranoside(25), rutin(26), and kaempferol 3-O-b-rutinoside(27). All of them, except compound 5, were isolated from this plant for the first time.

The Study on Induction and Proliferation of Tube Bulbs in Lilium brownii

With different parts of bulb scale as explants, the proliferation method of Guizhou Lilium brownii were studied with 3% sodium hypochlorite and MS medium with different concentrations of hormones. The results show that it is feasible to disinfect the bulbs of Lilium brownii with 3% sodium hypoehlorite, moreover, the sodium hypochlorite is very cheap and harmless to researchers, experimental materials and environment. MS ＋ NAA 0.3 mg/L ＋ 6-BA 1.5 mg/L is optimum for the induction of bulbs and, the basal part of Lilium brownie is the optimum explants. After culture for 25 d on the same medium, the tube bulbs could be obtained with the characteristics of high propagation coefficient, strong and new roots. The survival rate is over 90% for transplantation of tube bulbs with diameter between 1-2cm. The method developed in the present study can proliferate abundant Lilium brownii seedling in short time.

Histological Structure Difference of Dog's Olfactory Bulb Between Different Age and Sex

The purpose of this article is to detect sex and age difference in the structure of the olfactory bulb in dogs by histological methods. The thickness of the olfactory bulbs layers and its main cells were analyzed comparatively with the methods of HE-staining and statistics, through which we studied the development course of dogs＇ olfactory bulb and the structural differences which affect the olfaction in both males and females. The results showed that between both male and female juveniles and adult males and females, the difference in thickness of each layer is not significant. But the difference in quantity of mitral cells between adult males and females was significant. Meanwhile, the structure of every layer in juvenile dogs was apparent while the volume and the weight of adult dogs＇ olfactory bulb and each layer＇s width increased significantly. On the other hand, the density of each layer＇s cells decreased apparently. Our results demonstrated that the olfactory bulb developed with age, and the apparent differences in morphology and quantity of mitral cells between males and females may be one of the reasons leading to the sexual variations of olfactory sensitivity.

Changes of Spontaneous Electrical Activities of Olfactory Bulb in Bufo gargarizans during Postembryonic Development

Objective] The aim of this study was to investigate the electrophysiological characteristics of spontaneous electrical activities of olfactory bulb in Bufo gargarizans during postembryonic development. [Method] Microelectrode technique was used to record extracellular spontaneous electrical activities of olfactory bulb in B. gar-garizans. [Result] Along with the development of olfactory bulb, the discharge types increased gradual y. Single spontaneous firing enhanced gradual y and it reached the maximum in the metamorphosis phase. The intensity of consecutive single sponta-neous firing changed slightly at the middle of post-embryonic development, but it was stil higher than in the early phase and the adult phase. Consecutive burst spontaneous firing frequency went down over time. [Conclusion] Along with the de-velopment of olfactory bulb, the neuronal excitability increases step by step and the neuronal electrical activities diversify gradualy.

Effect of Phytohormones on Adventitious Bud Differentiation from Bulb Scales of Oriental Lily Test-tube Plantlets

[Objective] The purpose of this study is to investigate the effects of differ- ent phytohormones on the adventitious bud differentiation of oriental lily. [Method] The bulb scales of the test-tube plantlets of Tiber, Rodina and Constanta were cul- tured in media supplemented with different cytokinin and auxin at different concen- tration, and then the adventitious buds in each treatment were calculated. [Result] Cytokinins had different influence on the adventitious bud differentiation of the three oriental lily cultivars. Among them, 6-BA had the best effect to induce the adventi- tious bud differentiation from bulb scales of Tiber and Rodina, but there was some difference in the optimal concentration. KT had the best effect to induce the adven- titious bud differentiation of Constanta. The auxins had little influence on the quality of the adventitious bud of the three oriental lily cultivars, but caused some difference in differentiation coefficients. [Conclusion] The most suitable media for the adventi- tious bud differentiation from bulb scales in vitro of Tiber, Rodina and Constanta were MS＋0.2 mg/L 6-BA＋0.2 mg/L 2,4-D, MS＋I.0 mg/L 6-BA＋0.2 mg/L IAA, MS＋ 1.0 mg/L KT＋0.5 mg/L 2,4-D, respectively.

Effects of total saponins of Panax notoginseng on immature neuroblasts in the adult olfactory bulb following global cerebral ischemia/reperfusion

The main active components extracted from Panax notoginseng are total saponins. They have been shown to inhibit platelet aggregation, increase cerebral blood flow, improve neurological behavior, decrease infarct volume and promote proliferation and differentiation of neural stem cells in the hippocampus and lateral ventricles. However, there is a lack of studies on whether total saponins of Panax notoginsertg have potential benefits on immature neuroblasts in the olfactory bulb following ischemia and reperfusion. This study established a rat model of global cerebral ischemia and reperfusion using four-vessel occlusion. Rats were administered total sa- ponins of Panax notoginseng at 75 mg/kg intraperitoneally 30 minutes after ischemia then once a day, for either 7 or 14 days. Total saponins of Panax notoginseng enhanced the number of dou- blecortin （DCX）＋ neural progenitor ceils and increased co-localization of DCX with neuronal nuclei and phosphorylated cAMP response element-binding/DCX＋ neural progenitor cells in the olfactory bulb at 7 and 14 days post ischemia. These findings indicate that following global brain ischemia/reperfusion, total saponins of Panax notoginseng promote differentiation of DCX＋ cells expressing immature neuroblasts in the olfactory bulb and the underlying mechanism is related to the activation of the signaling pathway of cyclic adenosine monophosphate response element binding protein.

New Bulb Turbine with Counter-rotating Tandem-runner

With the increasing demand for the clean sustainable power, the turbine design urgently turns to increase the capability significantly toward higher head for generating larger power. Currently, there are many studies in the field of the bulb turbine with single-stage runner, though reports about counter-rotating tandem-runner are rare. However, the further high-head application with the single-stage runner is very difficult to achieve due to the limit of the specific speed. In this paper, a new bulb turbine with the tandem-runner is designed in order to substantially increase the applicable limit toward higher head with larger power. A half of the net head is absorbed by the frontal runner which can generate output power, while the remaining half is absorbed by the rear runner. To generate the Euler energy required for the rear runner, the frontal runner has the counter-rotation against the rear runner so that the counter-rotating tandem-runner can meet the purpose of double head and power under the same size as the conventional bulb turbine. Supply and demand of Euler energy between the two runners are thoroughly optimized through the detailed flow analysis, in order to secure the stable operation. As a result, the interference of Euler energies between the outflow from the frontal runner and the inflow to the rear runner is confirmed to be very small on the counter-rotating interface between the two runners. The prediction method of on-cam performance between the two adjustable runners is also developed numerically, which provides optimal flow between the two runners. This research provides a theoretical basis for the optimal design and operation of the counter-rotating tandem-runner bulb turbines.

Spontaneous firing in olfactory bulb neurons of Bufo bufo gargarizans in and after hibernation

Microelectrode technique was used to record the spontaneous electrical activities of the neurons in olfactory bulb of the Bufo bufo gargarizans, both in hibernation and after hibemation. This study investigated the electrophysiological characteristics of amphibian olfactory bulb in the period of hibernation and after hibernation and its effects on the start of hibernation and spontaneous awakening. The research showed four forms of spontaneous firings： single spontaneous firing, burst spontaneous firing, irregular spontaneous firing and consecutive single spontaneous firing. The single spontaneous firing includes slow depolarized spontaneous firing and fast depolarized spontaneous firing, and the slow depolarized spontaneous firing occurs only during the hibernation period. In hibernation, the low amplitude and low frequency firing with a longer duration may be relevant to maintaining the tonicity of the central nervous system in toads that are in hibernation, and this kind of firing may also provide an excited basis for their arousal from hibernation. After hibernation, the amplitude and frequency of firing increase, but the firing duration gets shorter. This form of short-term firing, which may be a phenomenon of sensory neurons fast adapting, is one of the neuronal mechanisms for the arousal of hibernating animals.

Hyperhomocysteinemia induces injury in olfactory bulb neurons by downregulating Hes1 and Hes5 expression

Hyperhomocysteinemia has been shown to be associated with neurodegenerative diseases; however, lesions or histological changes and mechanisms underlying homocysteine-induced injury in olfactory bulb neurons remain unclear. In this study, hyperhomocysteinemia was induced in apolipoprotein E-deficient mice with 1.7% methionine. Pathological changes in the olfactory bulb were observed through hematoxylin-eosin and Pischingert staining. Cell apoptosis in the olfactory bulb was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling （TUNEL） staining. Transmission electron microscopy revealed an abnormal ultrastructure of neurons. Furthermore, immunoreactivity and expression of the hairy enhancer of the split 1 （Hesl） and Hess were measured using immunohistochemistry, immunofluorescence, and western blot assay. Our results revealed no significant structural abnormality in the ol- factory bulb of hyperhomocysteinemic mice. However, the number of TUNEL-positive cells increased in the olfactory bulb, lipofuscin and vacuolization were visible in mitochondria, and the expression of Hes1 and Hes5 decreased. These findings confirm that hyperhomocyste- inemia induces injury in olfactory bulb neurons by downregulating Hes1 and Hes5 expression.

Combined VEGF/PDGF improves olfactory regeneration after unilateral bulbectomy in mice

The olfactory receptor neurons lining the nasal cavity have a remarkable capacity to regenerate throughout life. They are replenished continuously and their axons make new connections within the olfactory bulb. However, some factors such as head trauma and skull base surgery damage the olfactory nerve which lead to olfactory dysfunction. Losing the sense of smell has considerable effects on quality of life and life-expectancy. Therefore, there is a clear need to find a treatment for olfactory dysfunction. One such potential treatment is growth factor therapy which showed promising results in the spinal cord and brain injuries. The aim of the present study was to investigate whether combined delivery of two growth factors, vascular endothelial growth factor and platelet-derived growth factor treatment can improve the olfactory neurons regeneration in mice. The degeneration of the olfactory neurons was induced by unilateral bulbectomy. The treatment group received 1.5 μg of the combined growth factors intranasally, while the control injured group received saline. Growth factor treatment significantly increased the number of immature neurons at 5 and 7 days post injury and also the number of mature olfactory neurons at 10 and 14 days post bulbectomy. Regenerating axons extended over a larger volume in the operated cavity in the treatment group compared to control group at 14 days post bulbectomy. The growth factor treatment also significantly reduced astrocytic glia scar in the operated cavity. The results indicate that the combined delivery of the growth factors has the potential to improve olfactory dysfunction.

Foliar spraying of aqueous garlic bulb extract stimulates growth and antioxidant enzyme activity in eggplant(Solanum melongena L.)

Recently,botanical extracts are gaining popularity as biostimulants in vegetable production.In present study,the effect of aqueous garlic bulb extract(AGE)was studied on the growth and physiology of eggplant grown in plastic tunnel.AGE was foliage sprayed with various frequencies,i.e.,0,S1(once),S2(twice)and S3(three times)at two independent growth stages,pre-and post-transplant.The results showed that the treated plants exhibited stimulatory responses in growth and physiology in accord with the repetition of AGE spray and growth stages of the plants,respectively.A single foliage sprayed pre-transplant resulted in improved growth,i.e.,plant morphology and biomass,and enhanced antioxidants enzymes(superoxide dismutase,SOD;peroxidase,POD),photosynthesis and chlorophyll abundance observed at vegetative,first flowering and fruit setting stages,respectively.However,thrice application inhibited the plant growth and development and resulted in lipid peroxidation,i.e.,increased malondialdehyde(MDA)content.In addition,the post-transplant application also showed growth stimulation and interestingly,an overall positive influence was observed with respect to the AGE application and no significant increase in the MDA content indicated the post-transplant seedlings responded well.Our findings demonstrate that AGE can act as a biostimulant to enhance the eggplant growth in plastic tunnel production.

NUMERICAL PREDICTION OF PROCESS-INDUCED RESIDUAL STRESSES IN GLASS BULB PANEL

A numerical simulation model for predicting residual stresses which arise during the solidification process of pressed glass bulb panel was developed. The solidification of a molten layer of glass between cooled parallel plates was used to model the mechanics of the buildup of residual stresses in the forming process. A thermorheologically simple thermoviscoelastic model was assumed for the material. The finite element method employed was based on the theory of shells as an assembly of flat elements. This approach calculates residual stresses layer by layer like a truly three-dimensional calculation, which is well suited for thin pressed products of complex shape. An experimental comparison was employed to verify the proposed models and methods.

The Dynamics of Changes in Starch and Lipid Droplets and Sub-Cellular Localization of β-Amylase During the Growth of Lily Bulbs

The ultra-structure of mother and outer daughter scales of Lilium Oriental hybrid Sorbonne were studied using transmission electron microscope to examine the sub-cellular localization of starch and lipid droplets during growth and development from shoot emergence to senescence.The contents of starch granules and lipid droplets in the cell of the mother scales decreased significantly from shoot emergence to anthesis,indicating that these scales served as a source for growth and development.After flowering,the number of starch granules and lipid droplets increased dramatically,and finally the cells were filled with the above molecules indicating that the bulb becomes a major sink during bulb enlargement.Ultrastructure observation also showed that symplastic pathway is the main pathway in cells in the exchange and transportation of material during bulb development.The activity of β-amylase,one of the key enzymes catalyzing starch breakdown,showed a similar trend.The enzyme sub-cellular localization via immune-gold electron-microscopy showed that βamylase was predominantly located together with starch granules,while the gold particles were scarcely found in other sub-cellular compartments.The result suggested that this enzyme is compartmented together with its functional substrate supporting its function in catalyzing starch breakdown in living plant cells.

Somatic Embryogenesis in Lily Bulb Scale Cultures

Abstract： Somatic embryogenesis from lily bulb scales has not been studied in details, although tissue culture methods have been applied to the propagation for decades. The effects of different kinds and concentration of auxins for oriental lily somatic embryogenesis were investigated （Lilium hybrida var. Sorbonne）. 2, 4-dichlorophenoxyacetic acid （2, 4-D）, thidiazuron （TDZ） and α-naphthaleneacetic acid （NAA） media with benzyladenine（6-BA） and lactalbumin hydrolysate （LH） were used for embryogenic callus in the darkness. The best response on embryogenic callus formation was obtained on MS media supplemented 2, 4-D 2.0 mg·L^-1, 6-BA 0.5 mg·L^-1 and LH 300 mg·L^-1. Transfer embryogenic callus to the media with TDZ, 6-BA, kinetin （KT） supplemented 2, 4-D. The highest number of somatic embryos has been produced on medium with 0.5 mg·L^-1 2, 4-D and 0.3 mg·L^-1 KT. Germinated embryos with shoot axes were changed to MS media with 6-BA 0.5 mg·L^-1. The results suggest that in vitro culture of somatic embryogenesis from lily bulb scales can be used for plant regeneration.

<i>Lily bulb</i>Nectar Produces Expectorant and Anti-Tussive Activities, and Suppresses Cigarette Smoke-Induced Inflammatory Response in the Respiratory Tract in Mice

Air pollutants pose a major environmental threat to the respiratory system. Pathogen invasion and the exposure to particulate matters in atmospheric air, particularly, cigarette smoke (CS), have been found to be associated with acute and chronic respiratory diseases, including asthma. Therefore, the search for agents that can protect the respiratory system against potentially harmful substances is of interest in preventive health. Lily bulb Nectar (LBN), which contains Lily bulb, Pyrus pyrifolia N., Siraitia grosvenorii and Apricot kernel as its ingredients, is a health supplement intended to improve the wellness of the respiratory system in humans. Lily bulb, Pyrus pyrifolia N., Siraitia grosvenorii and Apricot kernel are commonly prescribed for the treatment of respiratory tract disorders such as bronchitis, pneumonia and cough in the practice of traditional Chinese medicine. Pharmacological studies have shown that these herbs can produce beneficial effects on the respiratory tract or even the lungs. In the present study, we investigated the effects of LBN on mouse respiratory tract function under normal and challenged conditions. LBN was first examined for its expectorant and anti-tussive activities in mice. The effect of LBN on long-term exposure to CS was also investigated. Our findings showed that long-term LBN treatment enhanced the expectorant activity and suppressed the SO2-induced coughing in mice. LBN treatment also suppressed the CS-induced inflammation in the respiratory tract, as assessed by differential cell count and cytokine production. In conclusion, long-term LBN consumption may produce beneficial effects on the respiratory tract function in humans, particularly in the face of challenge by irritants in the inhaling air.

HadISDH.extremes Part Ⅰ:A Gridded Wet Bulb Temperature Extremes Index Product for Climate Monitoring

HadISDH.extremes is an annually updated global gridded monthly monitoring product of wet and dry bulb temperature–based extremes indices,from January 1973 to December 2022.Data quality,including spatial and temporal stability,is a key focus.The hourly data are quality controlled.Homogeneity is assessed on monthly means and used to score each gridbox according to its homogeneity rather than to apply adjustments.This enables user-specific screening for temporal stability and avoids errors from inferring adjustments from monthly means for the daily maximum values.For general use,a score(HQ Flag)of 0 to 6 is recommended.A range of indices are presented,aligning with existing standardised indices.Uniquely,provision of both wet and dry bulb indices allows exploration of heat event character—whether it is a“humid and hot”,“dry and hot”or“humid and warm”event.It is designed for analysis of long-term trends in regional features.HadISDH.extremes can be used to study local events,but given the greater vulnerability to errors of maximum compared to mean values,cross-validation with independent information is advised.

HadISDH.extremes Part Ⅱ:Exploring Humid Heat Extremes Using Wet Bulb Temperature Indices

Heat events may be humid or dry.While several indices incorporate humidity,such combined indices obscure identification and exploration of heat events by their different humidity characteristics.The new HadISDH.extremes global gridded monitoring product uniquely provides a range of wet and dry bulb temperature extremes indices.Analysis of this new data product demonstrates its value as a tool for quantifying exposure to humid verses dry heat events.It also enables exploration into“stealth heat events”,where humidity is high,perhaps enough to affect productivity and health,while temperature remains moderate.Such events may not typically be identified as“heat events”by temperature-focused heat indices.Over 1973-2022,the peak magnitude of humid extremes(maximum daily wet bulb temperature over a month;T_(w)X)for the global annual mean increased significantly at 0.13±0.04℃(10 yr)^(−1),which is slightly slower than the global annual mean T_(w) increase of 0.22±0.04℃(10 yr)^(−1).The frequency of moderate humid extreme events per year(90th per-centile daily maxima wet bulb temperature exceedance;T_(w)X90p)also increased significantly at 4.61±1.07 d yr^(−1)(10 yr)^(−1).These rates were slower than for temperature extremes,TX and TX90p,which respectively increased significantly at 0.27±0.04℃(10 yr)^(−1) and 5.53±0.72 d yr^(−1)(10 yr)^(−1).Similarly,for the UK/Europe focus region,JJA-mean T_(w)X increased significantly,again at a slower rate than for TX and mean T_(w).HadISDH.extremes shows some evidence of“stealth heat events”occurring where humidity is high but temperature remains more moderate.