Abstract To identify factors that are required for proper pollen wall formation, we have characterized the T-DNA-tagged, dex1mutation of Arabidopsis, which results in defective pattern formation. This study reports isolation and molecular characterization DEX1 morphological ultrastructural analyses dex1 plants.DEX1 encodes a novel plant protein is predicted to be membrane associated contains several potential calcium-binding domains. Pollen development plants parallels wild-type until early...

Sexual reproduction requires the specification of cells with distinct fates in plants and animals. The EMS1 (also known as EXS) leucine-rich repeat receptor-like kinase (LRR-RLK) TPD1 small protein play key roles regulating somatic reproductive cell fate determination Arabidopsis anthers. Here, we show that ectopic expression causes abnormal differentiation In addition, activity functional EMS1. Yeast two-hybrid, pull-down, coimmunoprecipitation analyses further demonstrate interacts vitro...

MicroRNAs (miRNAs) have emerged as key regulators of gene expression at the post-transcriptional level in both plants and animals. However, specific functions MIRNAs (MIRs) mechanisms regulating their are not fully understood. Previous studies showed that miR160 negatively regulates three genes encode AUXIN RESPONSE FACTORs (ARF10, -16, -17). Here, we characterized floral organs carpels (foc), an Arabidopsis mutant with a Ds transposon insertion 3′ regulatory region MIR160a. foc exhibit...

Few studies have described aquatic organisms interacting with manufactured nanoparticles. One key factor in determining these materials potential toxicity is the extent to which particles accumulate tissues. This may be most important for as they contact large quantities of water through their feeding behavior. We examined uptake and release gold filter-feeding Daphnia magna. were exposed sublethal concentrations nanoparticles 1, 6, 12, or 24 hours. Transmission Electron Microscopy was used...

A fundamental feature of sexual reproduction in plants and animals is the specification reproductive cells that conduct meiosis to form gametes, associated somatic provide nutrition developmental cues ensure successful gamete production. The anther, which male organ seed plants, produces microsporocytes (pollen mother cells) surrounding cells. yield pollen via meiosis, cells, particularly tapetum, are required for normal development pollen. It not known how affect differentiation these vice...

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) is the most toxic congener of a large class environmental pollutants. Several studies have shown that TCDD exposure reduced fecundity and ovulatory rate in rats increased incidence endometriosis monkeys. Recent work suggests TCDD's endocrine-disrupting effects are, at least part, caused by direct action ovary. Although factors involved TCDD-induced toxicity are still under investigation, several induces programmed cell death, or apoptosis,...

Abstract The stamen, which consists of an anther and a filament, is the male reproductive organ in flower. specification stamen identity Arabidopsis (Arabidopsis thaliana) controlled by combination B genes APETALA3 (AP3) PISTILLATA, C gene AGAMOUS (AG), E SEPALLATA1 (SEP1) to SEP4. “floral organ-building” SPOROCYTELESS/NOZZLE (SPL/NZZ) plays central role regulating cell differentiation. However, much less known about how identity” floral organ-building interact control development. In this...

Mutations in human (Homo sapiens) ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 (ETHE1) result the complex metabolic disease ethylmalonic encephalopathy, which is characterized part by brain lesions, lactic acidemia, excretion of acid, and ultimately death. ETHE1-like genes are found a wide range organisms; however, biochemical physiological role(s) ETHE1 have not been examined outside context encephalopathy. In this study we Arabidopsis (Arabidopsis thaliana) determined effect an loss-of-function...

The role of polyploidy in facilitating invasiveness introduced plants has not been well explored. Examination traits diploid and polyploid both their native ranges can shed light on evolutionary processes occurring postintroduction invasive plants. We determined the distribution prevalence cytotypes Solidago gigantea its range (USA) (Europe), measured a suite biochemical, physiological, reproductive characters for from continents. Tetraploids were most frequent cytotype encountered...

Rhizobium sp. IRBG74 develops a classical nitrogen-fixing symbiosis with the aquatic legume Sesbania cannabina (Retz.). It also promotes growth of wetland rice (Oryza sativa L.), but little is known about rhizobial determinants important for these interactions. In this study, we analyzed colonization S. and using strain dually marked β-glucuronidase green fluorescent protein. This bacterium colonized by crack entry through root hair infection under flooded non-flooded conditions,...

Abstract We characterized 81 isolates of picoplankton and other small planktonic coccoid green algae from Lake Itasca, Itasca State Park, MN, USA. Sequence analysis examination by light microscopy revealed three common algae: Pseudodictyosphaerium/Korshpalmella spp. (Chlorophyceae), Choricystis (Trebouxiophyceae) a previously undescribed autosporic coccoid. The Pseudodictyosphaerium Korshpalmella species that were evaluated all possessed identical 18S ribosomal DNA (rDNA) rbcL sequences, but...

T-shape radial spokes regulate flagellar beating. However, the precise function and molecular mechanism of these remain unclear. Interestingly, Chlamydomonas reinhardtii flagella lacking a dimeric heat shock protein (HSP) 40 at spokehead–spokestalk juncture appear normal in length composition but twitch actively while cells jiggle without procession, resembling central pair (CP) mutant. HSP40− begin swimming upon electroporation with recombinant HSP40. Surprisingly, rescue doesn't require...

Abstract Germline determination is essential for species survival and evolution in multicellular organisms. In most flowering plants, formation of the female germline initiated with specification one megaspore mother cell (MMC) each ovule; however, molecular mechanism underlying this key event remains unclear. Here we report that spatially restricted auxin signaling promotes MMC fate Arabidopsis . Our results show microRNA160 (miR160) targeted gene ARF17 ( AUXIN RESPONSE FACTOR17 ) required...

Accurate placement of extracellular materials is a critical part cellular development. To study how cells achieve this accuracy, we use formation pollen apertures as model. In Arabidopsis (Arabidopsis thaliana), three regions on the surface lack deposition wall exine and develop into apertures. developing pollen, INAPERTURATE POLLEN1 (INP1) protein acts marker for preaperture domains, assembling there punctate lines. understand mechanism aperture formation, studied dynamics INP1 expression...

Image feature detector and descriptor algorithms have made a big advance in almost every area of computer vision applications including object localisation, tracking, mobile robot mapping, watermarking, panorama stitching 3D surface reconstruction by assisting the detection description points set given images. In this paper, we evaluate performance four robust namely SIFT, SURF, BRIEF ORB on multi-view microscopic samples obtained scanning electron microscope (SEM), widely used equipment...

Formation of pollen wall exine is preceded by the development several transient layers extracellular materials deposited on surface developing grains. One such layer primexine (PE), a thin, ephemeral structure that present only for short period time and difficult to visualize study. Recent genetic studies suggested PE key factor in formation exine, making it critical understand its composition dynamics formation. In this study, we used high-pressure frozen/freeze-substituted samples...