Structure and function of secretory glochids and nectar composition in two Opuntioideae (Cactaceae) species

Botany ◽  
2020 ◽  
Vol 98 (8) ◽  
pp. 425-437
Author(s):  
Stefany Cristina de Melo Silva ◽  
Silvia Rodrigues Machado ◽  
Massimo Nepi ◽  
Tatiane Maria Rodrigues
Keyword(s):  
High Performance ◽  
Light And Electron Microscopy ◽  
Secretory Activity ◽  
Amino Acid Profile ◽  
Structure And Function ◽  
Parenchyma Cells ◽  
Median Region ◽  
And Function ◽  
Similar Amino Acid ◽  
Shed Light

Cactaceae exhibit highly modified spines that are considered to be extrafloral nectaries (EFNs). Despite their ecological and taxonomical relevance in this family, little is known on their structure and function. We have described the anatomy, ontogenesis, and ultrastructure of the secretory glochids in two Opuntioideae species. Young cladodes of Brasiliopuntia brasiliensis (Willd.) A. Berger and Nopalea cochenillifera (L.) Salm-Dyck were processed for light and electron microscopy studies. The composition of the secretions was analyzed by high performance liquid chromatography. The secretory glochids were soft, massive, and barbed, as well as translucent. Hyaline droplets on the secretory glochid apex were collected by aggressive ants. The secretory glochids originated from the areolar meristem, beginning as small protuberances formed by protoderm and ground meristem. Mature secretory glochids consisted of a central multiseriate axis of ground cells covered by uniseriate epidermis with a continuous cuticle, and exhibited three regions: (i) dilated vascularized base with parenchyma cells exhibiting features associated to nectar secretion; (ii) elongated median region with juxtaposed fusiform non-lignified parenchyma cells; and (iii) tapered apical portion with immature fibers loosely arranged cells. The exudate was sucrose-dominant with a similar amino acid profile in both species. Our results shed light on the secretory activity of glochids in Cactaceae and their role in cactus–ant interactions.

The evolution of air-breathing respiratory faculties in craniotes

2019 ◽  
pp. 177-191
Author(s):  
Steven F. Perry ◽  
Markus Lambertz ◽  
Anke Schmitz
Keyword(s):  
High Performance ◽  
Body Wall ◽  
Structure And Function ◽  
Control Of Breathing ◽  
Body Wall Muscle ◽  
Positive Pressure ◽  
Limiting Factor ◽  
Swim Bladder ◽  
Body Wall Musculature ◽  
And Function

The origin of lungs from a swim bladder, swim bladder from lungs, or both from a relatively undifferentiated respiratory pharynx remains unresolved. Once present, the lungs can be ventilated by a positive-pressure buccal pump, which can be easily derived from the gill ventilation sequence in a lungfish, or by negative-pressure aspiration. Although aspiration breathing is characteristic of amniotes, it has also been observed in a lungfish and body wall muscle contraction in response to respiratory stimuli has even been reported in lamprey larvae. The hypaxial body wall musculature used for aspiration breathing is also necessary for locomotion in most amniotes, just when respiratory demand is greatest. This paradox, called Carrier’s constraint, is a major limiting factor in the evolution of high-performance faculties, and the evolution of anatomical and physiological specializations that circumvent it characterize most major amniote groups. Serendipitous combinations have resulted in evolutionary cascades and high-performance groups such as birds and mammals. Complementing evolution are the capacities for acclimatization and adaptation not only in the structure and function of the gas exchanger, but also in the control of breathing and the composition of the blood.

Effect of basolateral acidification on the frog oxynticopeptic cell

1990 ◽  
Vol 259 (4) ◽  
pp. G564-G570 ◽  
Author(s):  
S. Arvidsson ◽  
K. Carter ◽  
A. Yanaka ◽  
S. Ito ◽  
W. Silen
Keyword(s):  
Electron Microscopy ◽  
Gastric Mucosa ◽  
Light And Electron Microscopy ◽  
Structure And Function ◽  
Intracellular Acidification ◽  
Intracellular Acidosis ◽  
Normal Morphology ◽  
And Function ◽  
Oxynticopeptic Cells

The effects of intracellular acidosis induced by acidification of the basolateral (nutrient) perfusate on the structure and function of the oxynticopeptic cell were studied in in vitro frog gastric mucosa. Changing the pH of the unbuffered nutrient perfusate (UNB) from 7.2 to 3.5 acidified the oxynticopeptic cell with no change in potential difference (PD) or resistance (R). Intracellular pH (pHi), PD, and R were 7.05 +/- 0.01, 16 +/- 1 mV, 165 +/- 7 omega.cm2 before and 6.44 +/- 0.01, 16 +/- 2 mV, 170 +/- 9 omega.cm2 after nutrient acidification. Acid secretion (H+) increased from 0.86 +/- 0.07 to 1.88 +/- 0.18 mu eq.cm-2.h-1. Addition of forskolin to tissues perfused with nutrient pH (pHn) 3.5 decreased PD to 2 +/- 2 mV and further increased H+ to 3.07 +/- 0.19 mu eq.cm-2.h-1. By light and electron microscopy oxynticopeptic cells perfused with UNB, pHn 3.5, appeared normal. Oxynticopeptic cells in tissues pretreated with omeprazole and then exposed to UNB, pHn 3.5, had extensive morphological damage. On increasing the pH of the nutrient perfusate from 3.5 to 7.2 there was prompt recovery of pHi in untreated and forskolin-stimulated mucosae (pHi 6.87 +/- 0.06 and 6.85 +/- 0.04) but no recovery of pHi in tissues pretreated with omeprazole or cimetidine (pHi 6.26 +/- 0.04 and 6.44 +/- 0.06, n = 6, 30 min after reexposure to UNB, pHn 7.2). We conclude that in a secreting mucosa intracellular acidification of the oxynticopeptic cell to pHi 6.4 is associated with normal morphology, PD, R, and increased H+, and that intracellular acidosis is not de facto deleterious.

scholarly journals Membrane proteins in nanotechnology

2013 ◽  
Vol 35 (1) ◽  
pp. 4-8
Author(s):  
Paul Curnow
Keyword(s):  
Protein Structure ◽  
Membrane Proteins ◽  
High Performance ◽  
Natural World ◽  
Structure And Function ◽  
One Dimension ◽  
Modern Life ◽  
Protein Structure And Function ◽  
Exciting Current ◽  
And Function

The potential for nanotechnology to transform modern life has been appreciated for several years. Generally, nanotechnology involves objects with at least one dimension of less than 100 nm. Such stuff is abundant in the natural world, and one of the most exciting current areas in nanoscience research is the use of proteins as nanoscale components of high-performance devices and as nanosized tools in their own right. Biochemists, with our relatively sophisticated and mature toolkit for understanding protein structure and function, are now saddling up to explore the wild frontiers of biological nanotechnology.

scholarly journals A new role for narrative in variationist sociolinguistics

2006 ◽  
Vol 16 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Barbara Johnstone
Keyword(s):  
Language Change ◽  
Structure And Function ◽  
Linguistic Features ◽  
Variationist Sociolinguistics ◽  
Central Interest ◽  
Narrative Functions ◽  
Object Of Study ◽  
And Function ◽  
Narrative Syntax ◽  
Shed Light

Labov and Waletzky’s (1997[1967]) path-breaking description of “narrative syntax” arose in the context of variationist sociolinguistic research, and narrative continues to be an important source of data for variationist’ work. In most of this work, however, narrative is not the object of study. Variationist sociolinguists are interested in the structure and function of sounds, words, and phrases found in narrative data, but they have not typically asked how the structure and function of narrative itself might bear on the questions about linguistic variation and language change that define their field. Here I suggest that close attention to the structure and function of narrative can, in fact, shed light on a topic of central interest to variationists, namely vernacular norm-formation. I argue that narratives about encounters with linguistic difference help create shared orientations to particular sets of nonstandard linguistic features and link them with region, class, and other sources of identity. I further suggest that narrative functions particularly well as a vehicle for language-ideological differentiation (Gal & Irvine, 1995) of this sort.

scholarly journals Covid-19 Trending Neologisms in Bosnia and Herzegovina

2021 ◽  
Vol 6 (3(16)) ◽  
pp. 207-228
Author(s):  
Jelena Ilić Plauc ◽  
Ivona Šetka Čilić
Keyword(s):  
Bosnia And Herzegovina ◽  
Structure And Function ◽  
Qualitative Design ◽  
New Words ◽  
Online Newspaper ◽  
And Function ◽  
Shed Light ◽  
Descriptive Qualitative

The Covid-19 pandemic has affected every single aspect of life including conversational practices both online and offline. New lexical and sociolinguistic changes have become part of our lives, which is especially vivid in the emergence of Covid-19 trending neologisms. The present study utilizes the descriptive-qualitative design in the analysis of morphological structures of neologisms in Bosnian/Croatian/Serbian languages. Specifically, the paper is based on the analysis of morphological structures of the neologisms that use the discourse of the Covid pandemic as a base/modifier, i.e., that contain either corona- / korona-, coronavirus- / koronavirus-, Covid-19- / Kovid-19-, and Covid- / Kovid- as a base of the neologism. The dataset consists of over 10,000 headlines related to Covid-19 information, found and collected in online newspaper sections Koronavirus – Dnevni Avaz (Bosnia and Herzegovina) between March 2020 and March 2021. The results show that there is an intensive usage of the Covid-19 neologisms, which manifests the dynamics of language as new words are used, added, and integrated into conversational practices daily. Moreover, the majority of these neologisms use the discourse of the Covid pandemic as a base/modifier. This paper aims to shed light not only on the meanings of the new words and their structure and function, but it can also serve as a foundation for creating a special Covid-19 glossary on the territory of Bosnia and Herzegovina.

Nature-derived, structure and function integrated ultra-thick carbon electrode for high-performance supercapacitors

2020 ◽  
Vol 8 (38) ◽  
pp. 20072-20081
Author(s):  
Kun Liu ◽  
Runwei Mo ◽  
Wujie Dong ◽  
Wei Zhao ◽  
Fuqiang Huang
Keyword(s):  
High Performance ◽  
Structure And Function ◽  
Carbon Electrode ◽  
Conductive Additive ◽  
Binder Free ◽  
And Function ◽  
Thick Electrode

A structure-engineered and heteroatom-functionalized carbon slice has been developed as binder-free, conductive-additive-free, and self-supporting ultra-thick electrode via a nature-based design.

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