In situ visualization of a simple bipartite kinetochore with a single microtubule attachment in Giardia intestinalis (Metamonada)

To understand general features in evolution of kinetochore organization, investigating a wide range of mitotic mechanisms in various non-model eukaryotes is necessary. A binucleate flagellate Giardia intestinalis is a representative of highly divergent eukaryotic lineage of Metamonads. FIB/SEM tomography was used to investigate ultrastructural details of its mitotic architecture, including kinetochores. Giardia undergoes semi-open mitosis, with the nuclear envelope remaining intact except for polar fenestrae, allowing microtubules to enter the nucleoplasm. At the onset of mitosis, the nuclear envelope bends inward, forming a concave depression at the spindle poles. Spindle microtubules emanate from a cytoplasmic fuzzy microtubule organizing center near the flagellar basal bodies. Kinetochoral microtubules enter the nucleoplasm and bind to kinetochores. A small bipartite kinetochore composed of a dense inner disk, approximately 46 nm in diameter, and a two-armed outer fork, is attached to just one microtubule. To our knowledge, this is the first in situ evidence of a one-microtubule attachment to a kinetochore, which could represent a basic eukaryotic situation.     

Acute effects of Amomum villosum Lour. fruit extract on postprandial glycemia and insulin secretion: A single-blind,placebo-controlled,crossover study in healthy subjects

BackgroundAmomum villosum Lour., (Zingiberaceae) an herbaceous plant in the ginger family, has been used to treat various diseases. In a single-blind, randomized, crossover study, we assessed the postprandial blood insulin and blood glucose responses in healthy subjects (n = 40) after the Amomum villosum water extract (AVE) (5 g/person) or a placebo (5 g/person) consumption.MethodsDuring each treatment course, the healthy subject consumed a regular late afternoon meal, followed by fasting for 12 h, and arrived at the clinical study center the next morning. Blood insulin and blood glucose levels were assessed at 0, 30, 60, 90, and 120 min after AVE consumption. Between each treatment, the subjects accomplished one week of a washout period.ResultsThe AVE intake demonstrated a significant (67.26%) decline in postprandial blood glucose AUC_{0–120 min} (incremental area under the curve from 0 to 120 min) versus the placebo (P = 0.011). Furthermore, AVE reduced postprandial blood insulin AUC_{0–120 min} by 59.95% compared to the placebo group (P < 0.003), supporting the blood glucose results.ConclusionThis study revealed that AVE consumption significantly reduced postprandial insulin and glucose levels in healthy individuals, due in part to inhibition of α-glucosidase, and glucose transport.     

Ultrastructure of the labellar epidermis in selected Maxillaria species (Orchidaceae)

The ultrastructure of the labellar epidermis of 13 species of Maxillaria and one hybrid was examined using low-vacuum scanning electron microscopy (SEM). The labellum may be homogeneous and glabrous or papillose, comprising one type of cell only, or heterogeneous with papillae, uniseriate trichomes and/or glands in various combinations. The trichomes are unbranched and multicellular with pointed or truncated tips. Moreover, in some taxa, moniliform trichomes occur, and these are thought to fragment with the formation of pseudopollen. Homogeneous and heterogeneous labellar organization may represent separate evolutionary lines. Preliminary results suggest that labellar features may provide additional taxonomic characters allowing determination of intrageneric affinities.     

A revision of the Dip lop salts group of dinoflagellates (Dinophyceae) based on material from the British Isles

SEM has made possible a detailed re-examination of the thecal plates of marine dinoflagellates belonging to the Diplopsalis group which have been collected in an extensive survey of the seas around the British Isles. Six genera are recognized: Diplopsalis, Diplopsalopsis, Dissodium, Oblea, Zygabikodinium and die new genus and species Boreadinium pisiformis Dodge 8c Hermes. The confused taxonomic history of the group is discussed, the valid species are listed and a key for the identification of the genera is given.     

MV-mimicking micelles loaded with PEG-serine-ACP nanoparticles to achieve biomimetic intra/extra fibrillar mineralization of collagen in vitro

Since their discovery, matrix vesicles (MVs) containing minerals have received considerable attention for their role in the mineralization of bone, dentin and calcified cartilage. Additionally, MVs' association with collagen fibrils, which serve as the scaffold for calcification in the organic matrix, has been repeatedly highlighted. The primary purpose of the present study was to establish a MVs–mimicking model (PEG-S-ACP/micelle) in vitro for studying the exact mechanism of MVs-mediated extra/intra fibrillar mineralization of collagen in vivo. In this study, high-concentration serine was used to stabilize the amorphous calcium phosphate (S-ACP), which was subsequently mixed with polyethylene glycol (PEG) to form PEG-S-ACP nanoparticles. The nanoparticles were loaded in the polysorbate 80 micelle through a micelle self-assembly process in an aqueous environment. This MVs–mimicking model is referred to as the PEG-S-ACP/micelle model. By adjusting the pH and surface tension of the PEG-S-ACP/micelle, two forms of minerals (crystalline mineral nodules and ACP nanoparticles) were released to achieve the extrafibrillar and intrafibrillar mineralization, respectively. This in vitro mineralization process reproduced the mineral nodules mediating in vivo extrafibrillar mineralization and provided key insights into a possible mechanism of biomineralization by which in vivo intrafibrillar mineralization could be induced by ACP nanoparticles released from MVs. Also, the PEG-S-ACP/micelle model provides a promising methodology to prepare mineralized collagen scaffolds for repairing bone defects in bone tissue engineering.     

Nutlet morphology in Hemigenia R.Br. and Microcorys R.Br. (Lamiaceae)

Nutlets of Hemigenia R.Br. and Microcorys R.Br. were examined using SEM. Significant variation, mainly useful at the infrageneric level, was found in nutlet shape, nature of the attachment scar, nature of surface sculpturing, exocarp cell shape and sculpturing, and nature of the indumentum. Typical nutlets are ovoidal, strongly reticulate or rugose. The exocarp cells are isodiametric and convex to papillate. Also common are cylindrical nutlets, often with longitudinal ridging and papillate exocarp cells. Surface pitting and concave exocarp cells are rare. A cladistic analysis of nutlet characters suggests both Hemigenia and Microcorys are polyphyletic, and Microcorys paraphyletic with respect to Westringia Sm. Notwithstanding that, the infrageneric classification of Hemigenia was largely supported, while in Microcorys, there was support for sect. Hemigenioides, but sects Anisandra and Microcorys were not resolved as distinct.     

Diagnostic Measures of Influence for s2

We present three intuitive diagnostic measures for judging the influence that single or multiple observations exert on the estimate s², the mean square error. The three measures are shown to be equivalent statistics. We discuss distributional properties of these measures and conclude with an example.     

Distribution of Fusarium wilt of Bambara nut (Vigna subterranea (L.) Verdc.) in farmers’ fields’ of Busia County in Western Kenya and its management using farmyard manure

A study was carried out to determine Fusarium wilt distribution in Bambara nut farmers’ fields and its management using farm yard manure (FYM). Four villages in Busia County were purposively sampled for the study. The data generated were subjected to analysis of variance and treatment means separated by least significant difference test. Fusarium wilt incidence in the fields ranged from 14.63 to 43.56%. In the greenhouse, FYM reduced the disease incidence by 10.2% and severity by 9.5% on the black landrace and 1.9 and 12.8%, respectively, on the red landrace. In the field, FYM reduced disease incidence by 9.1% and severity by 6.9% on the black landrace and 10.4 and 10.4%, respectively, on the red landrace. Farm yard manure had the lowest area under disease progress curve irrespective of the landrace. The study confirmed the presence of the pathogen in the fields and the ability to manage the disease using FYM.