Real-Time Monitoring Method for Radioactive Substances Using Monolithic Active Pixel Sensors (MAPS).

This study presents a real-time monitoring technique for radioactive substances that meets safety management needs. We studied the accumulation characteristics of radiation response signals of monolithic active pixel sensors (MAPSs) based on their response and discrimination ability to gamma (γ) photon or neutron radiation. The radiation status of the radioactive substances was determined by monitoring the accumulation data of radiation responses. As per the results, Am-Be and 252Cf radiation response signals are primarily concentrated in the range of 0-70 pixels. Response signals of 60Co and 137Cs γ-ray were concentrated in two regions; there was a peak in the region with a pixel value of less than 50, and a plateau in the region with a pixel value of more than 75. Therefore, the results are able to discriminate between spectra. Furthermore, we designed a radioactivity monitoring system that is able to examine multiple radioactive materials. Its working principle is that a change in the accumulation of radioactivity monitoring data indicates a radiation change during the last accumulation cycle. This study provides vital technical support for the long-term supervision of radioactive substances.

Fiber-Based Triboelectric Nanogenerator for Mechanical Energy Harvesting and Its Application to a Human-Machine Interface.

Mechanical energy harvesters including piezoelectric nanogenerators, electromagnetic generators and triboelectric nanogenerators (TENG) used to convert the mechanical motion into electricity are more and more important in the recent decades. Specifically, the fiber-based TENG (FTENG) has gained considerable favors due to its flexibility, light weight, and high environmental tolerance for the wearable devices. The traditional FTENGs made of Teflon result in better performance but are not suitable for long-term wear in person. Here, we propose a novel FTENG using a flexible micro-needle-structured polydimethylsiloxane (MN-PDMS) together with the comfortable commercially available 2D-polyester fibers, and electroless nickel-plated cotton cloth of which two are widely used in human daily life. The MN-PDMS is formed by a laser engraved mold for improving its output performance of FTENG compared to the flat-PDMS. The open-circuit voltage (Voc) and the short-circuit current (Isc) of MN-FTENG increased to 73.6 V and 36 µA, respectively, which are 34% and 37% higher than the flat-FTENG. In terms of power, the performance of MN-FTENG reaches 1.296 mW which is 89% higher than that of flat-TENG and it can also light up 90 LEDs. For application, human motion at the joints can be detected and collected with various signals that are used for the human-machine interface (HMI) through the cooperation of components for the Internet of Things (IoT). It can light up the LED bulb through MN-FTENG to potentially develop IoT HMI systems for human motion control of robot in the future.

Penalized joint generalized estimating equations for longitudinal binary data.

In statistical research, variable selection and feature extraction are a typical issue. Variable selection in linear models has been fully developed, while it has received relatively little attention for longitudinal data. Since a longitudinal study involves within-subject correlations, the likelihood function of discrete longitudinal responses generally cannot be expressed in analytically closed form, and standard variable selection methods cannot be directly applied. As an alternative, the penalized generalized estimating equation (PGEE) is helpful but very likely results in incorrect variable selection if the working correlation matrix is misspecified. In many circumstances, the within-subject correlations are of interest and need to be modeled together with the mean. For longitudinal binary data, it becomes more challenging because the within-subject correlation coefficients have the so-called Fréchet-Hoeffding upper bound. In this paper, we proposed smoothly clipped absolute deviation (SCAD)-based and least absolute shrinkage and selection operator (LASSO)-based penalized joint generalized estimating equation (PJGEE) methods to simultaneously model the mean and correlations for longitudinal binary data, together with variable selection in the mean model. The estimated correlation coefficients satisfy the upper bound constraints. Simulation studies under different scenarios are made to assess the performance of the proposed method. Compared to existing PGEE methods that specify a working correlation matrix for longitudinal binary data, the proposed PJGEE method works much better in terms of variable selection consistency and parameter estimation accuracy. A real data set on Clinical Global Impression is analyzed for illustration.

CcMYB12 Positively Regulates Flavonoid Accumulation during Fruit Development in Carya cathayensis and Has a Role in Abiotic Stress Responses.

Flavonoid, an important secondary metabolite in plants, is involved in many biological processes. Its synthesis originates from the phenylpropane metabolic pathway, and it is catalyzed by a series of enzymes. The flavonoid biosynthetic pathway is regulated by many transcription factors, among which MYB transcription factors are thought to be key regulators. Hickory (Carya cathayensis) is an economic forest tree species belonging to the Juglandaceae family, and its fruit is rich in flavonoids. The transcriptome of exocarp and seed of hickory has previously been sequenced and analyzed by our team, revealing that CcMYB12 (CCA0691S0036) may be an important regulator of flavonoid synthesis. However, the specific regulatory role of CcMYB12 in hickory has not been clarified. Through a genome-wide analysis, a total of 153 R2R3-MYB genes were identified in hickory, classified into 23 subclasses, of which CcMYB12 was located in Subclass 7. The R2R3-MYBs showed a differential expression with the development of hickory exocarp and seed, indicating that these genes may regulate fruit development and metabolite accumulation. The phylogenetic analysis showed that CcMYB12 is a flavonol regulator, and its expression trend is the same as or opposite to that of flavonol synthesis-related genes. Moreover, CcMYB12 was found to be localized in the nucleus and have self-activation ability. The dual-luciferase reporter assay demonstrated that CcMYB12 strongly bonded to and activated the promoters of CcC4H, CcCHS, CcCHI, and CcF3H, which are key genes of the flavonoid synthesis pathway. Overexpression of CcMYB12 in Arabidopsis thaliana could increase the content of total flavonoids and the expression of related genes, including PAL, C4H, CHS, F3H, F3'H, ANS, and DFR, in the flavonoid synthesis pathway. These results reveal that CcMYB12 may directly regulate the expression of flavonoid-related genes and promote flavonoid synthesis in hickory fruit. Notably, the expression level of CcMYB12 in hickory seedlings was significantly boosted under NaCl and PEG treatments, while it was significantly downregulated under acid stress, suggesting that CcMYB12 may participate in the response to abiotic stresses. The results could provide a basis for further elucidating the regulation network of flavonoid biosynthesis and lay a foundation for developing new varieties of hickory with high flavonoid content.

Low dose rate γ-ray detection using a MAPS camera under a neutron radiation environment.

We present γ-ray radiation detection in a neutron radiation environment using a monolithic active pixel sensor (MAPS) camera without conversion or shielding layers. The measured output signal is the sum of the pedestal value, noise, and real radiation response signal. The sensor response shows that the MAPS camera is sensitive to neutrons and can capture a single photon. The number of pixels with a signal exceeding 100 exhibits a strong dependence on the dose rate and is the best indicator of this value. Therefore, a MAPS camera can be efficiently used as a radiation detection sensor in a robotic system, further limiting human errors in performing radiation detection in complex nuclear radiation environments.

Genome-wide identification of lncRNAs during hickory (Carya cathayensis) flowering.

Non-coding RNAs with lengths greater than 200 bp are known as long non-coding RNAs (lncRNAs), and these RNAs play important role in gene regulation and plant development. However, to date, little is known regarding the role played by lncRNAs during flowering in hickory (Carya cathayensis). Here, we performed whole transcriptome RNA-sequencing of samples from hickory female and male floral buds, in which three samples (H0311PF, H0318PF, and H0402PF) represent pre-flowering, flowering, and post-flowering, respectively, while eight male samples collected from May 8th to June 13th as this time course are the key stage for male floral bud differentiation. We identified 2163 lncRNAs in hickory during flowering, containing 213 intronic, 1488 intergenic, and 462 antisense lncRNAs. We noticed that 510 and 648 lncRNAs were differentially expressed corresponding to female and male floral buds, respectively. And some of the lncRNAs were in a tightly tissue-specific or stage-specific manner. To further understand the roles of the lncRNAs, we predicted the function of the lncRNAs in cis- and trans-acting modes. The results showed that 924 lncRNAs were cis-correlated with 1536 protein-coding genes, while 1207 lncRNAs co-expressed (trans-acting) with 7432 protein-coding genes (R > 0.95 or R < - 0.95). These lncRNAs were all enriched in flower development-associated biological processes, i.e., circadian rhythm, vernalization response, response to gibberellin, inflorescence development, floral organ development, etc. To further understand the relationships between lncRNAs and floral-core genes, we build a co-expressing lncRNA-mRNA flowering network. We classified these floral genes into different pathway (photoperiod, vernalization, gibberellin, autonomous, and sucrose pathway) according to their particular functions. We found a set of lncRNAs that preferentially expressed in these pathways. The network showed that some lncRNAs (i.e., XLOC_038669, XLOC_017938) functioned in a particular flowering time pathway, while others (i.e., XLOC_011251, XLOC_04110) were involved in multiple pathway. Furthermore, some lncRNAs (i.e., XLOC_038669, XLOC_009597, and XLOC_049539) played roles in single or multiple pathways via interaction with each other. This study provides a genome-wide survey of hickory flower-related lncRNAs and will contribute to further understanding of the molecular mechanism underpinning flowering in hickory.

In vitro gene expression and mRNA translocation from transformed walnut (Juglans regia) rootstocks expressing DsRED fluorescent protein to wild-type scions.

KEY MESSAGE: An in vitro grafting method was developed for examining gene translocation from rootstock to scion in walnut. Results showed the DsRED gene itself was not translocated but expressed mRNA was. Grafting is widely used in plants, especially in fruit and nut crops. Selected rootstocks can control scion growth and physiological traits, including shortening of the juvenile phase and controlling tree size. Rootstocks also can provide improved soil adaptation and pathogen resistance. Development of genetically modified (GM) fruit crops has progressed recently, but commercial cultivation is still limited due to the time required for evaluation and issues with deregulation. In this study, we evaluated the stability of DsRED marker gene expression in in vitro walnut shoots and examined translocation of the gene and its mRNA from transformed rootstock to wild-type scion. Results show that DsRED was expressed uniformly in transformed tissue-cultured shoots. When used as in vitro rootstocks, these had good graft affinity with wild-type control scion. PCR and qRT-PCR analysis showed that the DsRED gene was not transported from rootstock to scion, but the transcribed mRNA was translocated. This result provides further evidence of gene signal transport from rootstock to scion in fruit and nut crops.

The mechanism of high contents of oil and oleic acid revealed by transcriptomic and lipidomic analysis during embryogenesis in Carya cathayensis Sarg.

BACKGROUND: Hickory (Carya cathayensis Sarg.) accumulates more than 70% oil and 90% unsaturated fatty acids with considerably high oleic acid in its mature embryo. The concurrent global trancriptomic and lipidomic analyses provided a framework for better understanding of glycerolipid biosynthesis and metabolism in the hickory nut. RESULTS: The synthetical regulation of numerous leading lipid-related genes harmonized with the oil accumulation and fatty acid conversion in embryo development. The high level of ACCase correlated positively with fatty acids de novo synthesis, and the synergy of DGAT2 and PDAT promoted the TAG assembly, and oleosins, caleosins and steroleosins were transcribed considerably high for timely energy reserve in oil body. Glycolysis possibly provided sufficient precursors and energy for lipid synthesis. The perfect harmonization of the high level of SAD with low level of FAD2 facilitated the oleic acid accumulation. And the ratio of FATA/FATB or SAD/FATB was proposed for determining the saturated degree of oil. The gene multi-copy event was generated probably for accommodating various survival environments. A thermotolerant defense system including TAG hydrolysis determinants, heat shock proteins, and high ratio of MUFA to PUFA constrained the lipid degradation and provided a guarantee for high lipid content. A batch of potential genes recruited from the co-expression network helps us to understand the lipid synthesis and the response to high temperature better. CONCLUSIONS: The high transcriptional levels of key genes in lipid synthesis promoted the oil accumulation, and the harmonious expression of key ones for unsaturated fatty acids led oleic acid to high levels.

Development of SSR Markers in Hickory (Carya cathayensis Sarg.) and Their Transferability to Other Species of Carya.

Hickory (Carya cathayensis Sarg.), an important nut-producing species in Southeastern China, has high economic value, but so far there has been no cultivar bred under species although it is mostly propagated by seeding and some elite individuals have been found. It has been found recently that this species has a certain rate of apomixis and poor knowledge of its genetic background has influenced development of a feasible breeding strategy. Here in this paper we first release SSR (Simple sequence repeat) markers developed in this species and their transferability to other three species of the same genus, Carya. A total of 311 pairs of SSR primers in hickory were developed based on sequenced cDNAs of a fruit development-associated cDNA library and RNA-seq data of developing female floral buds and could be used to distinguish hickory, C. hunanensis Cheng et R. H. Chang ex R. H. Chang et Lu, C. illinoensis K. Koch (pecan) and C. dabieshanensis M. C. Liu et Z. J. Li, but they were monomorphic in both hickory and C. hunanensis although multi-alleles have been identified in all the four species. There is a transferability rate of 63.02% observed between hickory and pecan and the markers can be applied to study genetic diversity of accessions in pecan. When used in C. dabieshanensis, it was revealed that C. dabieshanensis had the number of alleles per locus ranging from 2 to 4, observed heterozygosity from 0 to 0.6667 and expected heterozygosity from 0.333 to 0.8667, respectively, which supports the existence of C. dabieshanensis as a separate species different from hickory and indicates that there is potential for selection and breeding in this species.

Integrated transcriptomic and lipidomic analysis provides key insights into lipid content changes during pecan (Carya illinoensis) fruit development.

Pecans [Carya illinoinensis (Wangenh.) K. Koch] are highly valued for their abundance of quality healthy lipids, positively impacting human health and making themselves a preferred choice for nutritionally rich foods. However, a comprehensive understanding of the high-resolution characteristics of pecan fruit lipid composition and its dynamic changes, as well as the transfer between embryo and pericarp during development, remains incomplete. In this study, through integrated multi-omics analysis, we observed significant spatiotemporal heterogeneity in lipid changes between the pericarp and embryo. It showed smaller fluctuations and more stable lipid levels in the pericarp while exhibiting a dynamic pattern of initially increasing and then decreasing lipid content in the embryo. In this study, a total of 52 differentially expressed genes were identified, related to fatty acid synthesis and metabolism pathways in the two tissues, with changes in oleic acid and linoleic acid composition being the primary features of the embryo. This research lays the foundation for further understanding the differential regulation mechanisms of lipid metabolism between embryo and pericarp. Overall, this study filled the knowledge gap regarding dynamic changes in pericarp lipid metabolites, provided crucial insights into the lipid metabolism network during pecan fruit development, and established a scientific basis for the genetic improvement of pecan crops.

Use of transcriptome sequencing to understand the pistillate flowering in hickory (Carya cathayensis Sarg.).

BACKGROUND: Different from herbaceous plants, the woody plants undergo a long-period vegetative stage to achieve floral transition. They then turn into seasonal plants, flowering annually. In this study, a preliminary model of gene regulations for seasonal pistillate flowering in hickory (Carya cathayensis) was proposed. The genome-wide dynamic transcriptome was characterized via the joint-approach of RNA sequencing and microarray analysis. RESULTS: Differential transcript abundance analysis uncovered the dynamic transcript abundance patterns of flowering correlated genes and their major functions based on Gene Ontology (GO) analysis. To explore pistillate flowering mechanism in hickory, a comprehensive flowering gene regulatory network based on Arabidopsis thaliana was constructed by additional literature mining. A total of 114 putative flowering or floral genes including 31 with differential transcript abundance were identified in hickory. The locations, functions and dynamic transcript abundances were analyzed in the gene regulatory networks. A genome-wide co-expression network for the putative flowering or floral genes shows three flowering regulatory modules corresponding to response to light abiotic stimulus, cold stress, and reproductive development process, respectively. Totally 27 potential flowering or floral genes were recruited which are meaningful to understand the hickory specific seasonal flowering mechanism better. CONCLUSIONS: Flowering event of pistillate flower bud in hickory is triggered by several pathways synchronously including the photoperiod, autonomous, vernalization, gibberellin, and sucrose pathway. Totally 27 potential flowering or floral genes were recruited from the genome-wide co-expression network function module analysis. Moreover, the analysis provides a potential FLC-like gene based vernalization pathway and an 'AC' model for pistillate flower development in hickory. This work provides an available framework for pistillate flower development in hickory, which is significant for insight into regulation of flowering and floral development of woody plants.

Design and Fabrication of Polymer Triboelectric Nanogenerators for Self-Powered Insole Applications.

Triboelectric nanogenerators (TENGs) are a kind of mechanical energy harvester with a larger force sensing range and good energy conversion, which is often applied to human kinetic energy collection and motion sensing devices. Polymer materials are the most commonly used materials in TENGs' triboelectric layers due to their high plasticity and good performance. Regarding the application of TENGs in insoles, research has often used brittle Teflon for high output performance together with hard materials, such as springs, for the mechanism to maintain its stability. However, these combined materials increase the weight and hardness of the insoles. Here, we propose a polyethylene terephthalate (PET)-based TENG with a micro-needle polydimethylsiloxane (PDMS) elastomer, referred to as MN-PDMS-TENG, to enhance performance and maintain comfort flexibility, and structural stability. Compared with a flat PDMS, the TENG with a microstructure enhances the output open-circuit voltage (Voc) from 54.6 V to 129.2 V, short-circuit current (Isc) from 26.16 µA to 64.00 µA, power from 684 µW to 4.1 mW, and ability to light up from 70 to 120 LEDs. A special three-layer TENG insole mechanism fabricated with the MN-PDMS-TENG and elastic materials gives the TENG insole high stability and the ability to maintain sufficient flexibility to fit in a shoe. The three-layer TENG insole transforms human stepping force into electric energy of 87.2 V, which is used as a self-powered force sensor. Moreover, with the calibration curve between voltage and force, it has a sensitivity of 0.07734 V/N with a coefficient of determination of R2 = 0.91 and the function between force and output voltage is derived as F = 12.93 V - 92.10 under human stepping force (300~550 N). Combined with a micro-control unit (MCU), the three-layer TENG insole distinguishes the user's motion force at different parts of the foot and triggers a corresponding device, which can potentially be applied in sports and on rehabilitation fields to record information or prevent injury.

Flavonoid Synthesis and Metabolism During the Fruit Development in Hickory (Carya cathayensis).

Hickory (Carya cathayensis) kernel is rich in powerful bioactive flavonoids, which can remove excess free radicals in the human body and play an important role in regulating the physiological metabolism of the plant. This study investigated the changes of flavonoids in hickory exocarp and embryo during development. In this study, 72 DEGs involved in the regulation of flavonoid biosynthesis in fruits were identified, and TT4, CCoAOMT1, UGT71D1, C4H, F3H, TT8, FLS1, and LDOX were identified as the core genes of flavonoid biosynthesis. A total of 144 flavonoid-related metabolites were detected by metabolite analysis. Transcriptome and metabolome analysis combined to construct the flavonoid biosynthesis regulatory pathway in the development stage of hickory fruit. Our results provide a theoretical basis for the exploration and regulation of functional genes related to flavonoid biosynthesis and metabolism in hickory and other plants and the breeding of new walnut varieties.

Safety and efficacy of a novel three-dimensional printed microporous titanium prosthesis for total wrist arthroplasty in the treatment of end-stage wrist arthritis.

Background: Total wrist arthroplasty is an effective treatment for end-stage wrist arthritis from all causes. However, wrist prostheses are still prone to complications such as prosthesis loosening and periprosthetic fractures after total wrist arthroplasty. This may be due to the wrist prosthesis imprecise matching with patient's bone. In this study, we designed and developed a personalized three-dimensional printed microporous titanium artificial wrist prosthesis (3DMT-Wrist) for the treatment of end-stage wrist joint, and investigated its safety and effectiveness. Methods: Total wrist arthroplasty was performed using 3DMT-Wrist in 14 cases of arthritis between February 2019 and December 2021. Preoperative and postoperative visual analog scale scores, QuickDASH scores, wrist range of motion, and wrist grip strength were evaluated. Data were statistically analyzed using the paired samples t-test. Results: After 19.7 ± 10.7 months of follow-up, visual analog scale decreased from 66.3 ± 8.9 to 6.7 ± 4.4, QuickDASH scores decreased from 47.4 ± 7.3 to 28.2 ± 7.6, grip strength increased from 5.6 ± 1.4 to 17.0 ± 3.3 kg. The range of motion improved significantly in palmar flexion (30.1° ± 4.9° to 44.9° ± 6.5°), dorsal extension (15.7° ± 3.9° to 25.8° ± 3.3°), ulnar deviation (12.2° ± 3.9° to 20.2° ± 4.3°) and radial deviation (8.2° ± 2.3° to 16.2 ± 3.1). No dislocation or loosening of the prosthetic wrist joint was observed. Conclusion: Total wrist arthroplasty using 3DMT-Wrist is a safe and effective new treatment for various types of end-stage wrist arthritis; it offers excellent pain relief and maintains the range of motion.

Accessible chromatin reveals regulatory mechanisms underlying cell fate decisions during early embryogenesis.

This study was conducted to investigate epigenetic landscape across multiple species and identify transcription factors (TFs) and their roles in controlling cell fate decision events during early embryogenesis. We made a comprehensively joint-research of chromatin accessibility of five species during embryogenesis by integration of ATAC-seq and RNA-seq datasets. Regulatory roles of candidate early embryonic TFs were investigated. Widespread accessible chromatin in early embryos overlapped with putative cis-regulatory sequences. Sets of cell-fate-determining TFs were identified. YOX1, a key cell cycle regulator, were found to homologous to clusters of TFs that are involved in neuron and epidermal cell-fate determination. Our research provides an intriguing insight into evolution of cell-fate decision during early embryogenesis among organisms.

Photosynthetic Mechanisms of Metaxenia Responsible for Enlargement of Carya cathayensis Fruits at Late Growth Stages.

Fruits of hickory (Carya cathayensis) are larger and their peel is greener after interspecific pollination by pecan (Carya illinoinensis; later pp fruits) than after intraspecific pollination by hickory (later ph fruits). Previous studies have found little genetic differences between offspring and their maternal parent, indicating that the observed trait differences between pp and ph fruits are due to metaxenia. Fruit development depends on the amount of photosynthetic assimilate available. Since there is no difference in photosynthesis of the associated leaves between pp and ph fruits, the larger size of the pp fruits might be attributed to changes in fruit photosynthesis caused by the different pollen sources. To elucidate to the photosynthetic mechanisms behind the metaxenia effect on fruit development in hickory, the effects of intraspecific and interspecific pollination regimes were examined in the present study. We observed the photosynthetic capacity in the peel of fruits and the related ecophysiological and morphological traits of both ph and pp fruits over a period of 120 days after pollination. Significant differences in the appearance and dry weight between ph and pp fruits were observed at 50 days after pollination (DAP). More than 70% of dry matter accumulation of the fruits was completed during 60-120 DAP, while the true photosynthetic rate of the associated leaves significantly decreased by about 50% during the same period. In several cell layers of the peel, the number of chloroplasts per cell was significantly higher in pp than in ph fruits. Similarly, the ribulose 1, 5-bisphosphate carboxylase (Rubisco) activity, the total chlorophyll content, and the nitrogen content were all significantly higher in pp than in ph fruits during all growth stages; and all of these physiological quantities were positively correlated with the gross photosynthetic rate of the fruits. We conclude that the enhanced photosynthetic capacity of pp fruits contributes to their fast dry matter accumulation and oil formation. This result will provide a theoretical basis for improving hickory fruit yields in practical cultivation.

The genomes of pecan and Chinese hickory provide insights into Carya evolution and nut nutrition.

BACKGROUND: Pecan (Carya illinoinensis) and Chinese hickory (C. cathayensis) are important commercially cultivated nut trees in the genus Carya (Juglandaceae), with high nutritional value and substantial health benefits. RESULTS: We obtained >187.22 and 178.87 gigabases of sequence, and ∼288× and 248× genome coverage, to a pecan cultivar ("Pawnee") and a domesticated Chinese hickory landrace (ZAFU-1), respectively. The total assembly size is 651.31 megabases (Mb) for pecan and 706.43 Mb for Chinese hickory. Two genome duplication events before the divergence from walnut were found in these species. Gene family analysis highlighted key genes in biotic and abiotic tolerance, oil, polyphenols, essential amino acids, and B vitamins. Further analyses of reduced-coverage genome sequences of 16 Carya and 2 Juglans species provide additional phylogenetic perspective on crop wild relatives. CONCLUSIONS: Cooperative characterization of these valuable resources provides a window to their evolutionary development and a valuable foundation for future crop improvement.

Transcriptome Analysis of Genes Involved in Lipid Biosynthesis in the Developing Embryo of Pecan (Carya illinoinensis).

Pecan (Carya illinoinensis) is an important woody tree species because of the high content of healthy oil in its nut. Thus far, the pathways and key genes related to oil biosynthesis in developing pecan seeds remain largely unclear. Our analyses revealed that mature pecan embryo accumulated more than 80% oil, in which 90% was unsaturated fatty acids with abundant oleic acid. RNA sequencing generated 84,643 unigenes in three cDNA libraries prepared from pecan embryos collected at 105, 120, and 165 days after flowering (DAF). We identified 153 unigenes associated with lipid biosynthesis, including 107 unigenes for fatty acid biosynthesis, 34 for triacylglycerol biosynthesis, 7 for oil bodies, and 5 for transcription factors involved in oil synthesis. The genes associated with fatty acid synthesis were the most abundantly expressed genes at 120 DAF. Additionally, the biosynthesis of oil began to increase while crude fat contents increased from 16.61 to 74.45% (165 DAF). We identified four SAD, two FAD2, one FAD6, two FAD7, and two FAD8 unigenes responsible for unsaturated fatty acid biosynthesis. However, FAD3 homologues were not detected. Consequently, we inferred that the linolenic acid in developing pecan embryos is generated by FAD7 and FAD8 in plastids rather than FAD3 in endoplasmic reticula. During pecan embryo development, different unigenes are expressed for plastidial and cytosolic glycolysis. Plastidial glycolysis is more relevant to lipid synthesis than cytosolic glycolysis. The 18 most important genes associated with lipid biosynthesis were evaluated in five stages of developing embryos using quantitative PCR (qPCR). The qPCR data were well consistent with their expression in transcriptomic analyses. Our data would be important for the metabolic engineering of pecans to increase oil contents and modify fatty acid composition.

Transcriptional profiling by DDRT-PCR analysis reveals gene expression during seed development in Carya cathayensis Sarg.

Hickory (Carya cathayensis Sarg.) seed has one of the highest oil content and is rich in polyunsaturated fatty acids (PUFAs), which kernel is helpful to human health, particularly to human brain function. A better elucidation of lipid accumulation mechanism would help to improve hickory production and seed quality. DDRT-PCR analysis was used to examine gene expression in hickory at thirteen time points during seed development process. A total of 67 unique genes involved in seed development were obtained, and those expression patterns were further confirmed by semi-quantitative RT-PCR and real time RT-PCR analysis. Of them, the genes with known functions were involved in signal transduction, amino acid metabolism, nuclear metabolism, fatty acid metabolism, protein metabolism, carbon metabolism, secondary metabolism, oxidation of fatty acids and stress response, suggesting that hickory underwent a complex metabolism process in seed development. Furthermore, 6 genes related to fatty acid synthesis were explored, and their functions in seed development process were further discussed. The data obtained here would provide the first clues for guiding further functional studies of fatty acid synthesis in hickory.

[Studies of chromosomal heredity and fertility of progenies (2n=49) crossed between river and swamp buffalo].

After analysis of reproduction records of two types of karyotypes (2n=50 & 2n=49) of triple crossbreed buffaloes (TCB) and studies of synaptinemal complex and sperm chromosome of 2n=49 TCB, the results showed that 2 sorts of normal gametes (n=24 and n=25) and 2 sorts of abnormal gametes (n=24+1 and n=25-1) were produced in 2n=49 TCB. Thus, both male and female of 2n=49 TCB are reproducible, and chromosomal polymorphyism (2n=50, 2n=49 & 2n=48) occurred in the progenies after intermating. But its fertility decreased because of aneuploidy combined between normal and abnormal gametes. Compared with 2n=50 TCB, the conception rates for individual inseminations and for whole year reduced 12.3% and 6.4%, calving interval were prolonged by 97.6 days, and calf numbers in its lifetime (up to 11-year old) were lower by approximate 1.5 calves, respectively.