Dynamic changes in primexine during the tetrad stage of pollen development.

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

Loss of THIN EXINE2 disrupts multiple processes in the mechanism of pollen exine formation.

Exine, the sporopollenin-based outer layer of the pollen wall, forms through an unusual mechanism involving interactions between two anther cell types: developing pollen and tapetum. How sporopollenin precursors and other components required for exine formation are delivered from tapetum to pollen and assemble on the pollen surface is still largely unclear. Here, we characterized an Arabidopsis (Arabidopsis thaliana) mutant, thin exine2 (tex2), which develops pollen with abnormally thin exine.

Members of the ELMOD protein family specify formation of distinct aperture domains on the pollen surface.

Pollen apertures, the characteristic gaps in pollen wall exine, have emerged as a model for studying the formation of distinct plasma membrane domains. In each species, aperture number, position, and morphology are typically fixed; across species they vary widely. During pollen development, certain plasma membrane domains attract specific proteins and lipids and become protected from exine deposition, developing into apertures.

The Role of INAPERTURATE POLLEN1 as a Pollen Aperture Factor Is Conserved in the Basal Eudicot (Papaveraceae).

Pollen grains show an enormous variety of aperture systems. What genes are involved in the aperture formation pathway and how conserved this pathway is in angiosperms remains largely unknown. () encodes a protein of unknown function, essential for aperture formation in Arabidopsis, rice and maize.

A species-specific functional module controls formation of pollen apertures.

Pollen apertures are an interesting model for the formation of specialized plasma-membrane domains. The plant-specific protein INP1 serves as a key aperture factor in such distantly related species as Arabidopsis, rice and maize. Although INP1 orthologues probably play similar roles throughout flowering plants, they show substantial sequence divergence and often cannot substitute for each other, suggesting that INP1 might require species-specific partners.

Prevalence of SARS-CoV-2 Contamination on Food Plant Surfaces as Determined by Environmental Monitoring.

Abstract: The SARS-CoV-2 pandemic has presented new challenges to food manufacturers. During the early phase of the pandemic, several large outbreaks of coronavirus disease 2019 (COVID-19) occurred in food manufacturing plants resulting in deaths and economic loss, with approximately 15% of personnel diagnosed as asymptomatic for COVID-19. Spread by asymptomatic and presymptomatic individuals has been implicated in large outbreaks of COVID-19.

Unification of Jiang 2016 and Prakash 2017 and the status of the genus Prakash 2017.

Based on the high phylogenetic relatedness of Prakash . 2017 and Jiang . 2016, it is proposed to unite them with retaining the latter name as having nomenclatural priority.

Looking below the surface in plants.

A new way to culture and image flowers is uncovering the processes that take place in reproductive cells buried deep in plants.

Formation of aperture sites on the pollen surface as a model for development of distinct cellular domains.

Pollen grains are covered by the complex extracellular structure, called exine, which in most species is deposited on the pollen surface non-uniformly. Certain surface areas receive fewer exine deposits and develop into regions whose structure and morphology differ significantly from the rest of pollen wall. These regions are known as pollen apertures.

Reclassification of Burkholderia insecticola as Caballeronia insecticola comb. nov. and reliability of conserved signature indels as molecular synapomorphies.

In the last 4 years, most of the species previously classified as members of the genus Burkholderia have been transferred to the novel genera Paraburkholderia, Caballeronia, Robbsia, Mycetohabitans and Trinickia. However, there have been objections to splitting the genus Burkholderiasensu lato, and based on this taxonomic opinion, strain RPE64, which has the 16S rRNA gene sequence identical to that of Caballeronia peredens LMG 29314, has recently been proposed as the type strain of Burkholderia insecticolasp. nov.

Changes in morphogen kinetics and pollen grain size are potential mechanisms of aberrant pollen aperture patterning in previously observed and novel mutants of Arabidopsis thaliana.

Pollen provides an excellent system to study pattern formation at the single-cell level. Pollen surface is covered by the pollen wall exine, whose deposition is excluded from certain surface areas, the apertures, which vary between the species in their numbers, positions, and morphology. What determines aperture patterns is not understood.

Quantitative Detection of Beef Contamination in Cooked Meat Products by ELISA.

Concerns about the contamination of meat products with undeclared meats, and new regulations for the declaration of meat adulterants have established the need for a rapid test to detect beef adulteration to 0.1% sensitivity. To address this need, Microbiologique, Inc.

Arabidopsis Protein Kinase D6PKL3 Is Involved in the Formation of Distinct Plasma Membrane Aperture Domains on the Pollen Surface.

Certain regions on the surfaces of developing pollen grains exhibit very limited deposition of pollen wall exine. These regions give rise to pollen apertures, which are highly diverse in their patterns and specific for individual species. pollen develops three equidistant longitudinal apertures.

Reclassification of Eubacterium combesii and discrepancies in the nomenclature of botulinum neurotoxin-producing clostridia: Challenging Opinion 69. Request for an Opinion.

To clarify the taxonomic position of Eubacterium combesii, the whole genome of its type strain, DSM 20696, was sequenced. Comparison of this sequence with known sequences of other bacteria confirmed that E. combesii represented a member of the Clostridium sporogenes/Clostridium botulinum Group I clade.

Quantitative Detection of Chicken and Turkey Contamination in Cooked Meat Products by ELISA.

: Concerns about the contamination of meat products with undeclared meats and new regulations for the declaration of meat adulterants have established the need for a rapid test to detect chicken and turkey adulteration. : To address this need, Microbiologique, Inc. has developed an ELISA that can quantify the presence of chicken and turkey down to 0.

Effect of aperture number on pollen germination, survival and reproductive success in Arabidopsis thaliana.

Background And Aims: Pollen grains of flowering plants display a fascinating diversity of forms, including diverse patterns of apertures, the specialized areas on the pollen surface that commonly serve as the sites of pollen tube initiation and, therefore, might play a key role in reproduction. Although many aperture patterns exist in angiosperms, pollen with three apertures (triaperturate) constitutes the predominant pollen type found in eudicot species. The aim of this study was to explore whether having three apertures provides selective advantages over other aperture patterns in terms of pollen survival, germination and reproductive success, which could potentially explain the prevalence of triaperturate pollen among eudicots.

INP1 involvement in pollen aperture formation is evolutionarily conserved and may require species-specific partners.

Pollen wall exine is usually deposited non-uniformly on the pollen surface, with areas of low exine deposition corresponding to pollen apertures. Little is known about how apertures form, with the novel Arabidopsis INP1 (INAPERTURATE POLLEN1) protein currently being the only identified aperture factor. In developing pollen, INP1 localizes to three plasma membrane domains and underlies formation of three apertures.

Formation of pollen apertures in Arabidopsis requires an interplay between male meiosis, development of INP1-decorated plasma membrane domains, and the callose wall.

In most plant species, surfaces of pollen grains display characteristic patterns of apertures, formed by the gaps in the pollen wall exine. The aperture patterns are species-specific and tend to be very precise, with pollen of each species usually developing a certain number of apertures placed at distinct positions and acquiring specific morphology. The precision with which pollen apertures are produced suggests that developing pollen grains possess robust mechanisms that allow them to specify particular membrane domains as the future-aperture sites and to protect these sites from exine deposition.

Quantitative Detection of Horse Contamination in Cooked Meat Products by ELISA.

Concerns about the contamination of meat products with horse meat and new regulations for the declaration of meat adulterants have highlighted the need for a rapid test to detect horse meat adulteration. To address this need, Microbiologique, Inc., has developed a sandwich ELISA that can quantify the presence of horse meat down to 0.

Quantitative Detection of Pork Contamination in Cooked Meat Products by ELISA.

Recent news of many cases of adulteration of meats with pork has bolstered the need for a way to detect and quantify the unwanted contamination of pork in other meats. To address this need, Microbiologique, Inc. has produced a sandwich ELISA assay that can rapidly quantify the presence of pork in cooked horse, beef, chicken, goat, and lamb meats.

Pollen Aperture Factor INP1 Acts Late in Aperture Formation by Excluding Specific Membrane Domains from Exine Deposition.

Accurate placement of extracellular materials is a critical part of cellular development. To study how cells achieve this accuracy, we use formation of pollen apertures as a model. In Arabidopsis (), three regions on the pollen surface lack deposition of pollen wall exine and develop into apertures.

Transfer of 13 species of the genus Burkholderia to the genus Caballeronia and reclassification of Burkholderia jirisanensis as Paraburkholderia jirisanensis comb. nov.

A recent study of a group of Burkholderia glathei-like bacteria resulted in the description of 13 novel species of the genus Burkholderia. However, our analysis of phylogenetic positions of these species and their molecular signatures (conserved protein sequence indels) showed that they belong to the genus Caballeronia, and we propose to transfer them to this genus. The reclassified species names are proposed as Caballeroniaarationis comb.

Clostridium tepidum sp. nov., a close relative of Clostridium sporogenes and Clostridium botulinum Group I.

Obligately anaerobic, Gram-stain-positive, spore-forming bacteria indistinguishable by pulsed-field gel electrophoresis were isolated from non-dairy protein shakes in bloated bottles. One of the isolates, strain IEH 97212T, was selected for further study. The strain was closely related to Clostridium sporogenes and Clostridium botulinum Group 1 based on 16S rRNA gene sequence similarities.