Axial resolution enhancement of light‐sheet microscopy by double scanning of Bessel beam and its complementary beam

The side lobes of Bessel beam will create significant out‐of‐focus background when scanned in light‐sheet fluorescence microscopy (LSFM), limiting the axial resolution of the imaging system. Here, we propose to overcome this issue by scanning the sample twice with zeroth‐order Bessel beam and another type of propagation‐invariant beam, complementary to the zeroth‐order Bessel beam, which greatly reduces the out‐of‐focus background created in the first scan. The axial resolution can be improved from 1.68 μm of the Bessel light‐sheet to 1.07 μm by subtraction of the two scanned images across a whole field‐of‐view of up to 300 μm × 200 μm × 200 μm. The optimization procedure to create the complementary beam is described in detail and it is experimentally generated with a spatial light modulator. The imaging performance is validated experimentally with fluorescent beads as well as eGFP‐labeled mouse brain neurons.      

Investigating seed dormancy in cotton (Gossypium hirsutum L.): understanding the physiological changes in embryo during after‐ripening and germination

• The dormancy of seeds of upland cotton can be broken during dry after‐ripening, but the mechanism of its dormancy release remains unclear.
• Freshly harvested cotton seeds were subjected to after‐ripening for 180 days. Cotton seeds from different days of after‐ripening (DAR) were sampled for dynamic physiological determination and germination tests. The intact seeds and isolated embryos were germinated to assess effects of the seed coat on embryo germination. Content of H₂O₂ and phytohormones and activities of antioxidant enzymes and glucose‐6‐phosphate dehydrogenase were measured during after‐ripening and germination.
• Germination of intact seeds increased from 7% upon harvest to 96% at 30 DAR, while embryo germination improved from an initial rate of 82% to 100% after 14 DAR. Based on T₅₀ (time when 50% of seeds germinate) and germination index, the intact seed and isolated embryo needed 30 and 21 DAR, respectively, to acquire relatively stable germination. The content of H₂O₂ increased during after‐ripening and continued to increase within the first few hours of imbibition, along with a decrease in abscisic acid (ABA) content. A noticeable increase was observed in gibberellic acid content during germination when ABA content decreased to a lower level. Coat removal treatment accelerated embryo absorption of water, which further improved the accumulation of H₂O₂ and changed peroxidase content during germination.
• For cotton seed, the alleviation of coat‐imposed dormancy required 30 days of after‐ripening, accompanied by rapid dormancy release (within 21 DAR) in naked embryos. H₂O₂ acted as a core link between the response to environmental changes and induction of other physiological changes for breaking seed dormancy.

     

Long-term Therapeutic Effects of Extracorporeal Shock Wave-Assisted Melatonin Therapy on Mononeuropathic Pain in Rats

We evaluated the ability of extracorporeal shock wave (ECSW)-assisted melatonin (Mel) therapy to offer an additional benefit for alleviating the neuropathic pain (NP) in rats. Left sciatic nerve was subjected to chronic constriction injury (CCI) to induce NP. Animals (n?=?30) were randomized into group 1 (sham-operated control), group 2 (CCI only), group 3 (CCI?+?ECSW), group 4 (CCI?+?Mel) and group 5 (CCI?+?ECSW?+?Mel). By days 15, 22 and 29 after CCI, the thermal paw withdrawal latency (TPWL) and mechanical paw withdrawal threshold (MPWT) were highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but they showed no difference between the later two groups (all p?<?0.0001). The protein expressions of inflammatory (TNF-α, NF-κB, MMP-9, IL-1ß), oxidative-stress (NOXs-1, -2, -4, oxidized protein), apoptotic (cleaved-caspase3, cleaved-PARP), DNA/mitochondrial-damaged (γ-H2AX/cytosolic-cytochrome C), microglia/astrocyte activation (ox42/GFAP), and MAPKs [phosphorylated (p)-p38, p-JNK, p-ERK] biomarkers in dorsal root ganglia neurons (DRGs) and in spinal dorsal horn were exhibited an opposite pattern of TPWL among the five groups (all p?<?0.0001). Additionally, protein expressions of Nav.1.3, Nav.1.8 and Nav.1.9 in sciatic nerve exhibited an identical pattern to inflammation among the five groups (all p?<?0.0001). The numbers of cellular expressions of MAPKs (p-ERK1/2+/peripherin?+?cells, p-ERK1/2+/NF200?+?cells and p-JNK+/peripherin?+?cells, p-JNK+/NF200?+?cells) and voltage-gated sodium channels (Nav.1.8+/peripherin?+?cells, Nav.1.8+/NF200?+?cells, Nav.1.9+/peripherin?+?cells, Nav.1.9+/NF200?+?cells) in small and large DRGs displayed an identical pattern to inflammation among the five groups (all p?<?0.0001). In conclusion, the synergistic effect of combined ECSW-Mel therapy is superior to either one alone for long-term improvement of mononeuropathic pain-induced by CCI in rats.

     

Non-invasive estimation of root zone soil moisture from coarse root reflections in ground-penetrating radar images

Plant and Soil - Root zone soil moisture is an important component in water cycling through the soil-plant-atmosphere continuum. However, its measurement in the field remains a challenge,...     

掺混氮肥配施抑制剂对土壤氮库的调控作用

采用冬小麦盆栽试验,探讨掺混氮肥(缓释肥N∶普通尿素N=1∶1)配施氮肥抑制剂NAM对冬小麦土壤铵态氮、硝态氮、微生物生物量氮和固定态铵含量及小麦产量、氮肥利用率的影响,分析不同处理土壤矿质氮库、微生物生物量氮库和固定态铵库的动态变化特征.试验共设6个处理,不施氮肥(CK)、普通尿素(U)、掺混氮肥(MU)、MU+2.5‰NAM(MUN₁)、MU+5‰NAM(MUN₂)和MU+7.5‰NAM(MUN₃).结果表明:与MU处理相比,MUN₂和MUN₃处理推迟了NH₄⁺-N峰值出现的时间;小麦整个生长季,添加NAM处理的土壤矿质氮平均含量比MU处理下降了5.3%～11.7%;分蘖期至抽穗期,MU处理的微生物生物量氮矿化量和矿化率分别为38.96 mg·kg^-1和91.5%,均高于U处理,而MUN₁、MUN₂和MUN₃处理分别为58.73 mg·kg^-1和83.3%、94.20 mg·kg^-1和94.6%、104.46 mg·kg^-1和96.3%,添加NAM处理固定态铵的释放量比MU处理提高了2.83~9.19 mg·kg^-1.通径分析结果显示,与MU处理相比,添加NAM减弱了土壤NH₄⁺-N库对NO₃^--N库的直接影响,增强了固定态铵库通过影响NH₄⁺-N库对NO₃^--N库的间接作用.同时,MUN₁、MUN₂和MUN₃处理的小麦籽粒产量较MU处理分别提高了31.6%、21.5%和22.9%,氮肥利用率分别提高了8.1%、13.5%和3.1%.综上,配施NAM通过对氮素释放及在土壤中转化的双重调控,延迟土壤NH₄⁺-N峰值出现的时间及后续向NO₃^--N的转化,提高微生物生物量氮和固定态铵的供氮作用,从而提高了作物产量和氮肥利用率.     

Gene expression profiles in different stem internodes reveal the genetic regulation of primary and secondary stem development in <Emphasis Type="Italic">Betula platyphylla</Emphasis>

Secondary growth of stems is an important process for the radial increase of trees. To gain an insight into the molecular mechanisms underlying stem development from primary to secondary growth and to provide information for molecular research and breeding in Betula platyphylla (birch), the gene expression profiles of material from the first, third, and fifth internodes (IN) of 3-month-old seedlings were analyzed. Compared with the first IN, 177 genes were up-regulated and 157 genes down-regulated in the third IN; in the fifth IN, 180 genes were up-regulated and 275 genes were down-regulated. The expressions of 24 genes were up-regulated and 6 genes were down-regulated in the fifth IN relative to the third IN. The differentially expressed genes were annotated as having roles in cambium, xylem, and phloem development and formation; including cell wall expansion, cellulose biosynthesis, lignin biosynthesis and deposition, xylem extension, cell wall modification, and growth hormone responses. The expressions of genes related to cell wall expansion and cellulose biosynthesis in the primary cell wall were down-regulated in the third and fifth IN relative to the first IN. Genes involved in lignin biosynthesis, xylem extension, and cellulose synthesis in the secondary cell wall were up-regulated in the third and fifth IN relative to the first IN. These results described the patterns of gene expression during stem development in birch and provided candidate genes for further functional characterization.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> outer membrane protein,HomC, shows geographic dependent polymorphism that is influenced by the Bab family

The array of outer membrane proteins (OMPs) found in Helicobacter pylori provides a crucial component for persistent colonization within the gastric niche. Not only does H. pylori harbor a wide number of OMPs, but these OMPs often vary across strains; this likely contributes to immune evasion, adaptation during long term colonization, and potentially differential disease progression. Previous work from our group described OMP differences among the Bab family (babA, babB, and babC) and Hom family (homA and homB) from 80 American H. pylori clinical isolates (AH) and 80 South Korean H. pylori clinical isolates (KH). In the current study, we expanded our investigation to include the less well characterized Hom family member, HomC.     

Apple Fruit Diameter and Length Estimation by Using the Thermal and Sunshine Hours Approach and Its Application to the Digital Orchard Management Information System

In apple cultivation, simulation models may be used to monitor fruit size during the growth and development process to predict production levels and to optimize fruit quality. Here, Fuji apples cultivated in spindle-type systems were used as the model crop. Apple size was measured during the growing period at an interval of about 20 days after full bloom, with three weather stations being used to collect orchard temperature and solar radiation data at different sites. Furthermore, a 2-year dataset (2011 and 2012) of apple fruit size measurements were integrated according to the weather station deployment sites, in addition to the top two most important environment factors, thermal and sunshine hours, into the model. The apple fruit diameter and length were simulated using physiological development time (PDT), an indicator that combines important environment factors, such as temperature and photoperiod, as the driving variable. Compared to the model of calendar-based development time (CDT), an indicator counting the days that elapse after full bloom, we confirmed that the PDT model improved the estimation accuracy to within 0.2 cm for fruit diameter and 0.1 cm for fruit length in independent years using a similar data collection method in 2013. The PDT model was implemented to realize a web-based management information system for a digital orchard, and the digital system had been applied in Shandong Province, China since 2013. This system may be used to compute the dynamic curve of apple fruit size based on data obtained from a nearby weather station. This system may provide an important decision support for farmers using the website and short message service to optimize crop production and, hence, economic benefit.