scholarly journals Scaling of cytoskeletal organization with cell size in Drosophila

2017 ◽  
Vol 28 (11) ◽  
pp. 1519-1529 ◽  
Author(s):  
Alison K. Spencer ◽  
Andrew J. Schaumberg ◽  
Jennifer A. Zallen
Keyword(s):  
Cell Size ◽  
Quantitative Imaging ◽  
Larval Growth ◽  
Fold Increase ◽  
Ventral Surface ◽  
Tissue Growth ◽  
Cell Length ◽  
Drosophila Embryo ◽  
Microtubule Network ◽  
Wide Range

Spatially organized macromolecular complexes are essential for cell and tissue function, but the mechanisms that organize micron-scale structures within cells are not well understood. Microtubule-based structures such as mitotic spindles scale with cell size, but less is known about the scaling of actin structures within cells. Actin-rich denticle precursors cover the ventral surface of the Drosophila embryo and larva and provide templates for cuticular structures involved in larval locomotion. Using quantitative imaging and statistical modeling, we demonstrate that denticle number and spacing scale with cell length over a wide range of cell sizes in embryos and larvae. Denticle number and spacing are reduced under space-limited conditions, and both features robustly scale over a 10-fold increase in cell length during larval growth. We show that the relationship between cell length and denticle spacing can be recapitulated by specific mathematical equations in embryos and larvae and that accurate denticle spacing requires an intact microtubule network and the microtubule minus end–binding protein, Patronin. These results identify a novel mechanism of micro­tubule-dependent actin scaling that maintains precise patterns of actin organization during tissue growth.

Larval description and habitat utilization of an amphidromous goby, Redigobius bikolanus (Gobiidae)

2018 ◽  
Vol 68 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Thanh Trung Tran ◽  
Hau Duc Tran ◽  
Huan Xuan Nguyen
Keyword(s):  
Developmental Stages ◽  
Larval Growth ◽  
Ventral Surface ◽  
The West ◽  
Asian Continent ◽  
Tropical Regions ◽  
Wide Range ◽  
Newly Hatched Larvae ◽  
Pelagic Stage ◽  
Made In

AbstractRedigobius bikolanus(Gobiidae), which is distributed widely in the tropical regions of the West Pacific, is categorized as an amphidromous fish. Such fish reproduce in fresh water and newly hatched larvae immediately drift downstream to the estuary and sea where they spend a pelagic stage before returning upstream as juveniles. The morphology of larvalR. bikolanushas been reported mainly from Japan, whereas little is known about the early stages of this species on the Asian continent. To understand larval growth of this goby, monthly and bimonthly collections with ichthyoplankton nets were made in the Tien Yen estuary in northern Vietnam, from October 2014 to September 2015. A total of 282 larvae (preflexion to postflexion stages, 2.3-5.4 mm body length) ofR. bikolanuswere collected from the center of the current in May, but none were captured in the waters near the banks. The larvae were similar in general morphology to those of common gobies, but could be distinguished from other gobiid genera by two very large stellate melanophores on the ventral surface of the trunk and tail. Descriptions ofR. bikolanuslarvae based on a series of wild specimens are provided. The fishes occurred in low salinities (0.2-2.3 PSU) within 1 m from the surface layer. Together with the wide range of size and developmental stages, this suggests that larvae ofR. bikolanusutilize the center of the current of the Tien Yen estuary as their nursery area. This habitat has not been recorded in Japan.

Relationship between guard cell length and cold hardiness in wheat

1994 ◽  
Vol 74 (1) ◽  
pp. 59-62 ◽  
Author(s):  
A. E. Limin ◽  
D. B. Fowler
Keyword(s):  
Water Content ◽  
Cold Tolerance ◽  
Cell Size ◽  
Guard Cell ◽  
Cold Hardiness ◽  
Cell Length ◽  
Crystal Formation ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Wide Range

Identification of plant characters associated with cold tolerance is useful for the development of plant-breeding selection procedures and understanding the underlying mechanisms of cold hardiness. This research investigates the association of guard cell length with cold tolerance and examines the relationship between cell size, as estimated from guard cell length, and other characters previously found to be highly correlated with cold tolerance in wheat (Triticum aestivum L. em. Thell.). Guard cell length was compared with field survival, LT50, tissue water content, and plant erectness of cultivars representing a wide range of cold tolerance levels. The three most cold-tolerant cultivars had the smallest cells, while the cultivar with the largest cell size was a spring type. There were significant (P ≤ 0.05) correlations between guard cell length and all cold-tolerance-related characters considered. Differences in guard cell length were most closely related to field survival as measured by Field Survival Index (FSI). Stepwise regression analysis indicated that cell size explained 45% of the variability in FSI. Cell size combined with plant erectness and tissue water content explained 88% of the variability in FSI. LT50 and cell size together explained 96% of the variability in FSI. The effects of cell size on cold hardiness may relate to its influence on cell water content and cellular mechanical stress during intercellular ice-crystal formation and freezing-induced dehydration. Guard cell size should be a useful selection tool in cultivar development programs that have increased cold hardiness as the breeding objective. Key words:Triticum aestivum, winter wheat, cold hardiness, guard-cell length, cell size

Structure, Function and Interactions of Tau: Particular Focus on Potential Drug Targets for the Treatment of Tauopathies

2018 ◽  
Vol 17 (5) ◽  
pp. 325-337 ◽  
Author(s):  
Hojjat Borna ◽  
Kasim Assadoulahei ◽  
Gholamhossein Riazi ◽  
Asghar Beigi Harchegani ◽  
Alireza Shahriary
Keyword(s):  
Tau Protein ◽  
Drug Targets ◽  
Brain Injuries ◽  
Potential Drug ◽  
Microtubule Network ◽  
Wide Range ◽  
Potential Risk Factors ◽  
Range Of Functions ◽  
Potential Drug Targets

Background & Objective: Neurodegenrative diseases are among the most widespread lifethreatening disorders around the world in elderly ages. The common feature of a group of neurodegenerative disorders, called tauopathies, is an accumulation of microtubule associated protein tau inside the neurons. The exact mechanism underlying tauopathies is not well-understood but several factors such as traumatic brain injuries and genetics are considered as potential risk factors. Although tau protein is well-known for its key role in stabilizing and organization of axonal microtubule network, it bears a broad range of functions including DNA protection and participation in signaling pathways. Moreover, the flexible unfolded structure of tau facilitates modification of tau by a wide range of intracellular enzymes which in turn broadens tau function and interaction spectrum. The distinctive properties of tau protein concomitant with the crucial role of tau interaction partners in the progression of neurodegeneration suggest tau and its binding partners as potential drug targets for the treatment of neurodegenerative diseases. Conclusion: This review aims to give a detailed description of structure, functions and interactions of tau protein in order to provide insight into potential therapeutic targets for treatment of tauopathies.

Feeding ecology of Symbolophorus californiensis larvae (Teleostei: Myctophidae) in the southern transition region of the western North Pacific

2009 ◽  
Vol 90 (6) ◽  
pp. 1249-1256 ◽  
Author(s):  
Chiyuki Sassa
Keyword(s):  
Transition Region ◽  
North Pacific ◽  
Western North Pacific ◽  
Developmental Stages ◽  
Feeding Habits ◽  
Larval Growth ◽  
Trophic Niche ◽  
Size Class ◽  
Gut Contents ◽  
Wide Range

The feeding habits of myctophid larvae of Symbolophorus californiensis were examined in the southern transition region of the western North Pacific where the main spawning and nursery grounds of S. californiensis are formed. This species is a key component of the pelagic ecosystems of this region, and their larvae attain one of the largest sizes among myctophids. To analyse gut contents larvae, including most life history stages after yolk-sac absorption (3.7 to 22.2 mm body length (BL)), were collected in the upper 100 m layer in 1997 and 1998. Feeding incidence was higher during the day than at night (53.1–92.3% versus 0–5.6%), and daytime feeding incidence increased gradually with larval growth. Larvae fed mainly on copepods of various developmental stages. Larvae of S. californiensis showed an ontogenetic change in their diet: larvae ≤7.9 mm BL (i.e. preflexion stage) fed mainly on copepod eggs and nauplii, while the larvae ≥8 mm BL consumed mainly calanoid copepodites such as Pseudocalanus and Paracalanus spp. In the largest size-class (16–22.2 mm BL), the furcilia stage of euphausiids was also an important prey item. There was an increase in the average prey size with growth in larvae ≤11.9 mm BL, while the number of prey eaten positively correlated with growth in larvae ≥12 mm BL. The trophic niche breadth also increased with larval growth, which would ensure a wide range of available food resources for the larger size-class larvae.

Abstract 316: A Potential Mechanism Involving mTOR For The Expression Of CTGF In Agonist-stimulated Adult Cardiomyocytes

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Kamala P Sundararaj ◽  
Sundaravadivel Balasubramanian ◽  
Dorea Pleasant ◽  
Dhandapani Kuppuswamy
Keyword(s):  
Mrna Expression ◽  
Wound Repair ◽  
Cardiac Fibrosis ◽  
Interstitial Fibrosis ◽  
Treatment Options ◽  
Tissue Growth ◽  
Dependent Manner ◽  
Potential Mechanism ◽  
Wall Stiffness ◽  
Wide Range

Cardiac hypertrophy ensues as a response to multiple stimuli, such as mechanical stress, neurohumoral activation, growth factors and cytokines. Connective Tissue Growth Factor (CTGF), a potent fibrogenic cytokine, regulates a wide range of biological functions including ECM deposition, wound repair, angiogenesis, migration, differentiation, survival and proliferation. While CTGF overexpression in fibroblasts has been shown to be responsible for fibrosis in various organs, controversy exists about the source of CTGF. Since interstitial fibrosis contributes to ventricular wall stiffness and impairs diastolic function, understating how key factors such as CTGF are expressed and released for the genesis of fibrosis in the hypertrophying heart is important to develop new treatment options. To this end, we explored the signaling pathway(s) involved in the phenylephrine (PE), a hypertrophic agonist, induced expression of CTGF by cardiomyocytes (CMs). Since mammalian target of rapamycin (mTOR) is reported to regulate PE-induced hypertrophic signaling, we hypothesize that mTOR plays a role in PE induced CTGF expression in CMs. To test if CMs produce CTGF, we treated adult feline CMs with phenylephrine. PE stimulated CTGF mRNA expression in a dose and time dependent manner. mTOR forms two distinct complexes, mTORC1 and mTORC2. Whereas both complexes are sensitive to a pharmacological inhibitor Torin1, only mTORC1 is sensitive to Rapamycin inhibition. Our results indicate that PE stimulated CTGF expression could be substantially enhanced by torin1 pretreatment of CMs. Moreover, shRNA mediated silencing of Rictor in CMs, one of the components of mTORC2, significantly augmented the PE induced CTGF mRNA expression. But mTORC1 inhibition using Rapamycin or activation of its downstream target S6K1 using Rapamycin resistant S6K1 adenovirus had no impact in PE -stimulated CTGF expression. The same trend was also observed in the level of secreted CTGF. In conclusion, these results strongly indicate that mTORC2 plays a repressive role in CTGF mRNA expression in adult CMs, and that the loss of such repression in PO myocardium might be a potential mechanism for the onset of cardiac fibrosis in hypertrophying myocardium.

Df31 is a novel nuclear protein involved in chromatin structure in Drosophila melanogaster

2001 ◽  
Vol 114 (1) ◽  
pp. 37-47 ◽  
Author(s):  
G. Crevel ◽  
H. Huikeshoven ◽  
S. Cotterill
Keyword(s):  
Cell Types ◽  
Drosophila Embryo ◽  
Cell Fractionation ◽  
General Function ◽  
Structural Protein ◽  
Chromosomal Structure ◽  
Binding Characteristics ◽  
Wide Range ◽  
Cellular Dna

We originally isolated the Df31 protein from Drosophila embryo extracts as a factor which could decondense Xenopus sperm, by removing the sperm specific proteins and interacting with histones to facilitate their loading onto DNA. We now believe that this protein has a more general function in cellular DNA metabolism. The Df31 gene encodes a very hydrophilic protein with a predicted molecular mass of 18.5 kDa. Immunostaining showed that Df31 was present in a wide range of cell types throughout differentiation and in both dividing and non-dividing cells. In all cases the protein is present in large amounts, comparable with the level of nucleosomes. Injection of antisense oligonucleotides to lower the level of Df31 in embryos caused severe disruption of the nuclear structure. Large irregular clumps of DNA were formed, and in most cases the amount of DNA associated with each clump was more than that found in a normal nucleus. Immunofluorescence, cell fractionation, and formaldehyde cross-linking show that Df31 is associated with chromatin and that a significant fraction of it binds very tightly. It also shows the same binding characteristics when loaded onto chromatin in vitro. Chromatin fractionation shows that Df31 is tightly associated with nucleosomes, preferentially with oligonucleosomes. Despite this no differences were observed in the properties of nucleosomes loaded in the in vitro system in the presence and absence of Df31. These results suggest that Df31 has a role in chromosomal structure, most likely acting as a structural protein at levels of folding higher than that of nucleosomes.

Energy intake and fur in summer- and winter-acclimated Siberian hamsters (Phodopus sungorus)

2001 ◽  
Vol 281 (2) ◽  
pp. R519-R527 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Alessandra Cabrera ◽  
Irving Zucker
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Ventral Surface ◽  
Phodopus Sungorus ◽  
Ambient Temperatures ◽  
Siberian Hamsters ◽  
Daily Food ◽  
Brown Adipose ◽  
Wide Range ◽  
The Impact

Few studies have directly addressed the impact of fur on seasonal changes in energy intake. The daily food intake of Siberian hamsters ( Phodopus sungorus) was measured under simulated summer and winter conditions in intact animals and those with varying amounts of pelage removed. Energy intake increased up to 44% above baseline control values for approximately 2–3 wk after complete shaving. Increases in food intake varied with condition and were greater in hamsters housed in short than long day lengths and at low (5°C) than moderate (23°C) ambient temperatures. Removal of 8 cm2 of dorsal fur, equivalent to 30% of the total dorsal fur surface, increased food intake, but removal of 4 cm2 had no effect. An 8-cm2 fur extirpation from the ventral surface did not increase food consumption. Food intake was not influenced differentially by fur removal from above brown adipose tissue hot spots. Fur plays a greater role in energy balance in winter- than summer-acclimated hamsters and conserves energy under a wide range of environmental conditions.

scholarly journals Inhibitory activities of short linear motifs underlie Hox interactome specificity in vivo

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Manon Baëza ◽  
Séverine Viala ◽  
Marjorie Heim ◽  
Amélie Dard ◽  
Bruno Hudry ◽  
...  
Keyword(s):  
Cell Fate ◽  
Drosophila Embryo ◽  
Traditional Role ◽  
Hox Proteins ◽  
Short Linear Motifs ◽  
Wide Range ◽  
Mouse Species ◽  
Inhibitory Activities ◽  
Linear Motifs

Hox proteins are well-established developmental regulators that coordinate cell fate and morphogenesis throughout embryogenesis. In contrast, our knowledge of their specific molecular modes of action is limited to the interaction with few cofactors. Here, we show that Hox proteins are able to interact with a wide range of transcription factors in the live Drosophila embryo. In this context, specificity relies on a versatile usage of conserved short linear motifs (SLiMs), which, surprisingly, often restrains the interaction potential of Hox proteins. This novel buffering activity of SLiMs was observed in different tissues and found in Hox proteins from cnidarian to mouse species. Although these interactions remain to be analysed in the context of endogenous Hox regulatory activities, our observations challenge the traditional role assigned to SLiMs and provide an alternative concept to explain how Hox interactome specificity could be achieved during the embryonic development.

scholarly journals Patterns of tillering and grain production of winter wheat at a wide range of plant densities.

1978 ◽  
Vol 26 (4) ◽  
pp. 383-398 ◽  
Author(s):  
A. Darwinkel
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Harvest Index ◽  
Plant Density ◽  
Fold Increase ◽  
Grain Production ◽  
Higher Plant ◽  
Grain Number ◽  
Wide Range ◽  
Plant Densities

The effect of plant density on the growth and productivity of the various ear-bearing stems of winter wheat was studied in detail to obtain information on the pattern of grain production of crops grown under field conditions. Strong compensation effects were measured: a 160-fold increase in plant density (5-800 plants/m2) finally resulted in a 3-fold increase in grain yield (282 to 850 g DM/m2). Max. grain yield was achieved at 100 plants/m2, which corresponded to 430 ears/m2 and to about 19 000 grains/m2. At higher plant densities more ears and more grains were produced, but grain yield remained constant. Tillering/plant was largely favoured by low plant densities because these allowed tiller formation to continue for a longer period and a greater proportion of tillers produced ears. However, at higher plant densities more tillers/unit area were formed and, despite a higher mortality, more ears were produced. The productivity of individual ears, from main stems as well as from tillers, decreased with increasing plant density and with later emergence of shoots. In the range from 5 to 800 plants/m2 grain yield/ear decreased from 2.40 to 1.14 g DM. At 800 plants/m2 nearly all ears originated from main stems, but with decreasing plant density tillers contributed increasingly to the number of ears. At 5 plants/m2, there were 23 ears/plant and grain yield/ear ranged from 4.20 (main stem) to 1.86 g DM (late-formed stems). Grain number/ear was reduced at higher densities and on younger stems, because there were fewer fertile spikelets and fewer grains in these spikelets. At the low density of 5 plants/m2, plants developed solitarily and grain yield/ear was determined by the number of grains/ear as well as by grain wt. Above 400 ears/m2, in this experiment reached at 100 plants/m2 and more, grain yield/ear depended solely on grain number, because the wt. of grains of the various stems were similar. The harvest index showed a max. of about 44% at a moderate plant density; at this density nearly max. grain yield was achieved. At low plant densities the harvest index decreased from 45% in main stems to about 36% in late-formed stems. However, no differences in harvest index existed between the various ear-bearing stems if the number of ears exceeded 400/m2. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Advanced Hydrogels for Cartilage Tissue Engineering: Recent Progress and Future Directions

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4199
Author(s):  
Mahshid Hafezi ◽  
Saied Nouri Khorasani ◽  
Mohadeseh Zare ◽  
Rasoul Esmaeely Neisiany ◽  
Pooya Davoodi
Keyword(s):  
Tissue Engineering ◽  
Cartilage Tissue Engineering ◽  
Cartilage Regeneration ◽  
Biomechanical Properties ◽  
Tissue Growth ◽  
Cartilage Tissue ◽  
Self Healing ◽  
Advantages And Disadvantages ◽  
Wide Range

Cartilage is a tension- and load-bearing tissue and has a limited capacity for intrinsic self-healing. While microfracture and arthroplasty are the conventional methods for cartilage repair, these methods are unable to completely heal the damaged tissue. The need to overcome the restrictions of these therapies for cartilage regeneration has expanded the field of cartilage tissue engineering (CTE), in which novel engineering and biological approaches are introduced to accelerate the development of new biomimetic cartilage to replace the injured tissue. Until now, a wide range of hydrogels and cell sources have been employed for CTE to either recapitulate microenvironmental cues during a new tissue growth or to compel the recovery of cartilaginous structures via manipulating biochemical and biomechanical properties of the original tissue. Towards modifying current cartilage treatments, advanced hydrogels have been designed and synthesized in recent years to improve network crosslinking and self-recovery of implanted scaffolds after damage in vivo. This review focused on the recent advances in CTE, especially self-healing hydrogels. The article firstly presents the cartilage tissue, its defects, and treatments. Subsequently, introduces CTE and summarizes the polymeric hydrogels and their advances. Furthermore, characterizations, the advantages, and disadvantages of advanced hydrogels such as multi-materials, IPNs, nanomaterials, and supramolecular are discussed. Afterward, the self-healing hydrogels in CTE, mechanisms, and the physical and chemical methods for the synthesis of such hydrogels for improving the reformation of CTE are introduced. The article then briefly describes the fabrication methods in CTE. Finally, this review presents a conclusion of prevalent challenges and future outlooks for self-healing hydrogels in CTE applications.

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