Characterization of Physiological Responses of Suspension Cells From Alligator Weed (Alternanthera Philoxeroides (Mart.); Griseb) to an Abrupt Increase in Salinity.

Dark-grown suspension cells of alligator weed (Alternanthera philoxeroides (Mart.) Griseb) were established in Murashige and Skoog medium and used to characterize several cellular responses to an abrupt increase in salinity (0 to 200 mol m\sp{-3} NaCl). The fresh weight and cell density of salt-treated cells of alligator weed more than doubled by 7 d. Cell viability declined to 77% by 1 d, but recovered to 86% by 7 d after salt treatment. These responses indicate that alligator weed cells survived and adapted to an abrupt increase in salinity. Osmotic potential (\psi\sb\pi) of salt-treated cells declined to the \psi\sb\pi of the salt treatment medium and symplastic volume decreased by 36% at 2 h. This decrease in \psi\sb\pi at 2 h was primarily due to increased (Na\sp+) and (Cl\sp-), although concentrations of K\sp+, reducing sugars and quaternary ammonium compounds (QAC) also increased. From 2 h to 6 h after transfer to salt treatment, there was further but slower decline in cellular \psi\sb\pi, an increase in symplastic volume and cellular turgor potential (\psi\sb{\rm p}) became positive. By 3 d, \psi\sb{\rm p} was similar in control and salt-treated cells and the fresh weight of salt-treated cells was increasing. Cellular concentrations of sucrose, proline and total free amino acids also increased in salt-treated cells at 7 d. Decreases in cellular (Na\sp+) and (Cl\sp-) between 1 and 7 d indicate efficient regulation of these ions in alligator weed cells during prolonged salinity. These responses to an abrupt increase in salinity were accompanied by increased staining and incorporation of \sp{35}S-methionine into two soluble polypeptides and induction of two membrane polypeptides as early as 12 h after the beginning of salt treatment. The response of alligator weed cells was distinct from that of tobacco cells, which did not attain positive \psi\sb{\rm p} during the first 24 h, exhibit recovery of cell viability by 7 d or show an increase in fresh weight over the 21 d period after an abrupt increase in salinity. These results characterize several facets of cellular response to salinity and demonstrate the value of the alligator weed suspension system for studies of plant response to salinity

Transcriptome profiling and validation of gene based single nucleotide polymorphisms (SNPs) in sorghum genotypes with contrasting responses to cold stress

Primer sequences for validation of bi-allelic variant calls. (DOCX 15 kb

Applying genotyping (TILLING) and phenotyping analyses to elucidate gene function in a chemically induced sorghum mutant population

<p>Abstract</p> <p>Background</p> <p>Sorghum [<it>Sorghum bicolor </it>(L.) Moench] is ranked as the fifth most important grain crop and serves as a major food staple and fodder resource for much of the world, especially in arid and semi-arid regions. The recent surge in sorghum research is driven by its tolerance to drought/heat stresses and its strong potential as a bioenergy feedstock. Completion of the sorghum genome sequence has opened new avenues for sorghum functional genomics. However, the availability of genetic resources, specifically mutant lines, is limited. Chemical mutagenesis of sorghum germplasm, followed by screening for mutants altered in important agronomic traits, represents a rapid and effective means of addressing this limitation. Induced mutations in novel genes of interest can be efficiently assessed using the technique known as Targeting Induced Local Lesion IN Genomes (TILLING).</p> <p>Results</p> <p>A sorghum mutant population consisting of 1,600 lines was generated from the inbred line BTx623 by treatment with the chemical agent ethyl methanesulfonate (EMS). Numerous phenotypes with altered morphological and agronomic traits were observed from M₂and M₃lines in the field. A subset of 768 mutant lines was analyzed by TILLING using four target genes. A total of five mutations were identified resulting in a calculated mutation density of 1/526 kb. Two of the mutations identified by TILLING and verified by sequencing were detected in the gene encoding caffeic acid <it>O</it>-methyltransferase (<it>COMT</it>) in two independent mutant lines. The two mutant lines segregated for the expected brown midrib (<it>bmr</it>) phenotype, a trait associated with altered lignin content and increased digestibility.</p> <p>Conclusion</p> <p>TILLING as a reverse genetic approach has been successfully applied to sorghum. The diversity of the mutant phenotypes observed in the field, and the density of induced mutations calculated from TILLING indicate that this mutant population represents a useful resource for members of the sorghum research community. Moreover, TILLING has been demonstrated to be applicable for sorghum functional genomics by evaluating a small subset of the EMS-induced mutant lines.</p

Comparisons of De Novo Transcriptome Assemblers in Diploid and Polyploid Species Using Peanut (Arachis spp.) RNA-Seq Data

The narrow genetic base and limited genetic information on Arachis species have hindered the process of marker-assisted selection of peanut cultivars. However, recent developments in sequencing technologies have expanded opportunities to exploit genetic resources, and at lower cost. To use the genetic information for Arachis species available at the transcriptome level, it is important to have a good quality reference transcriptome. The available Tifrunner 454 FLEX transcriptome sequences have an assembly with 37,000 contigs and low N50 values of 500-751 bp. Therefore, we generated de novo transcriptome assemblies, with about 38 million reads in the tetraploid cultivar OLin, and 16 million reads in each of the diploids, A. duranensis K38901 and A. ipaënsis KGBSPSc30076 using three different de novo assemblers, Trinity, SOAPdenovo-Trans and TransAByss. All these assemblers can use single kmer analysis, and the latter two also permit multiple kmer analysis. Assemblies generated for all three samples had N50 values ranging from 1278-1641 bp in Arachis hypogaea (AABB), 1401-1492 bp in Arachis duranensis (AA), and 1107-1342 bp in Arachis ipaënsis (BB). Comparison with legume ESTs and protein databases suggests that assemblies generated had more than 40% full length transcripts with good continuity. Also, on mapping the raw reads to each of the assemblies generated, Trinity had a high success rate in assembling sequences compared to both TransAByss and SOAPdenovo-Trans. De novo assembly of OLin had a greater number of contigs (67,098) and longer contig length (N50 = 1,641) compared to the Tifrunner TSA. Despite having shorter read length (2 × 50) than the Tifrunner 454FLEX TSA, de novo assembly of OLin proved superior in comparison. Assemblies generated to represent different genome combinations may serve as a valuable resource for the peanut research community

Microglial activation and connectivity in Alzheimer disease and aging

OBJECTIVE Alzheimer disease (AD) is characterized by amyloid β (Aβ) plaques and neurofibrillary tau tangles, but increasing evidence suggests that neuroinflammation also plays a key role, driven by the activation of microglia. Aβ and tau pathology appear to spread along pathways of highly connected brain regions, but it remains elusive whether microglial activation follows a similar distribution pattern. Here, we assess whether connectivity is associated with microglia activation patterns. METHODS We included 32 Aβ-positive early AD subjects (18 women, 14 men) and 18 Aβ-negative age-matched healthy controls (10 women, 8 men) from the prospective ActiGliA (Activity of Cerebral Networks, Amyloid and Microglia in Aging and Alzheimer's Disease) study. All participants underwent microglial activation positron emission tomography (PET) with the third-generation mitochondrial 18 kDa translocator protein (TSPO) ligand [18 F]GE-180 and magnetic resonance imaging (MRI) to measure resting-state functional and structural connectivity. RESULTS We found that inter-regional covariance in TSPO-PET and standardized uptake value ratio was preferentially distributed along functionally highly connected brain regions, with MRI structural connectivity showing a weaker association with microglial activation. AD patients showed increased TSPO-PET tracer uptake bilaterally in the anterior medial temporal lobe compared to controls, and higher TSPO-PET uptake was associated with cognitive impairment and dementia severity in a disease stage-dependent manner. INTERPRETATION Microglial activation distributes preferentially along highly connected brain regions, similar to tau pathology. These findings support the important role of microglia in neurodegeneration, and we speculate that pathology spreads throughout the brain along vulnerable connectivity pathways. ANN NEUROL 2022

Individual regional associations between Aβ-, tau- and neurodegeneration (ATN) with microglial activation in patients with primary and secondary tauopathies.

β-amyloid (Aβ) and tau aggregation as well as neuronal injury and atrophy (ATN) are the major hallmarks of Alzheimer's disease (AD), and biomarkers for these hallmarks have been linked to neuroinflammation. However, the detailed regional associations of these biomarkers with microglial activation in individual patients remain to be elucidated. We investigated a cohort of 55 patients with AD and primary tauopathies and 10 healthy controls that underwent TSPO-, Aβ-, tau-, and perfusion-surrogate-PET, as well as structural MRI. Z-score deviations for 246 brain regions were calculated and biomarker contributions of Aβ (A), tau (T), perfusion (N1), and gray matter atrophy (N2) to microglial activation (TSPO, I) were calculated for each individual subject. Individual ATN-related microglial activation was correlated with clinical performance and CSF soluble TREM2 (sTREM2) concentrations. In typical and atypical AD, regional tau was stronger and more frequently associated with microglial activation when compared to regional Aβ (AD: βT = 0.412 ± 0.196 vs. βA = 0.142 ± 0.123, p < 0.001; AD-CBS: βT = 0.385 ± 0.176 vs. βA = 0.131 ± 0.186, p = 0.031). The strong association between regional tau and microglia reproduced well in primary tauopathies (βT = 0.418 ± 0.154). Stronger individual associations between tau and microglial activation were associated with poorer clinical performance. In patients with 4RT, sTREM2 levels showed a positive association with tau-related microglial activation. Tau pathology has strong regional associations with microglial activation in primary and secondary tauopathies. Tau and Aβ related microglial response indices may serve as a two-dimensional in vivo assessment of neuroinflammation in neurodegenerative diseases

Biomass and Cellulosic Ethanol Production of Forage Sorghum Under Limited Water Conditions

This study presents results from a 2-year evaluation of biomass and cellulosic ethanol (EtOH) production potential of forage sorghum (Sorghum bicolor L. Moench) cultivars differing in brown midrib trait (i.e., bmr12) under dryland (no irrigation) and limited irrigation (2.88 mm day−1; subsurface drip) in the semiarid Southern High Plains of the USA. Commercial cultivar Sorghum Partners 1990 (SP 1990, conventional non-bmr) produced significantly more biomass (29–62 %) than a bmr12 cultivar PaceSetter bmr (PS bmr) under irrigated and dryland conditions during both years of this study. However, PS bmr biomass had higher cellulosic EtOH conversion efficiency than SP 1990 in both years according to simultaneous saccharification and fermentation analysis. Irrigation resulted in 26–49 % more biomass and 28–72 % more cellulosic EtOH production during both growing seasons, indicating that limited irrigation had favorable effects on both biomass and biofuel production. In the first year, when precipitation was below average, both cultivars produced similar amounts of cellulosic EtOH. During the second year, when precipitation was above average, higher biomass production of SP 1990 resulted in 28 % higher cellulosic EtOH production than PS bmr when averaged across both irrigated and dryland conditions. The large range of cellulosic EtOH production (1,600 to 3,380 L ha−1) during the 2 years of this study was primarily driven by differences in water availability that resulted from precipitation and irrigation. Our findings indicates that chemical composition and biomass yield potential of sorghum cultivars are critical factors that affect biomass and biofuel production under limited water conditions

Pilea sohayakiensis Kitam.

原著和名: ソハヤキミヅ科名: イラクサ科 = Urticaceae採集地: 和歌山県 東牟婁郡 熊野川町 小口〜畝畑 (紀伊 東牟婁郡 熊野川町 小口〜畝畑 )採集日: 1980/9/22採集者: 萩庭丈壽整理番号: JH007931国立科学博物館整理番号: TNS-VS-95793