scholarly journals Feeding in murky waters: acclimatization and landmarks improve foraging efficiency of zebrafish ( Danio rerio ) in turbid waters

2019 ◽  
Vol 15 (7) ◽  
pp. 20190289
Author(s):  
M. A. Sekhar ◽  
Richa Singh ◽  
Anuradha Bhat ◽  
Manjari Jain
Keyword(s):  
Foraging Efficiency ◽  
Visual Environment ◽  
Behavioural Plasticity ◽  
Foraging Success ◽  
Visual Landmarks ◽  
Water Turbidity ◽  
Turbid Waters ◽  
And Function ◽  
Extended Exposure

Fish inhabiting human-dominated ecosystems are prone to altered sensory environments in which they must live and function. Increased turbidity is one such change that they must deal with. We tested whether an increase in water turbidity and the presence of visual landmarks (coloured stones) affect the foraging efficiency of wild zebrafish. We also tested the influence of extended exposure to differing turbidity levels on the subsequent foraging efficiency of acclimatized individuals. Feeding latency (time taken to find food) increased significantly with increase in turbidity levels from a minimum of 4 s to ca 300 s. However, extended exposure of fish to varying levels of turbidity decreased feeding latencies in acclimatized conditions, indicating that acclimatization to the immediate visual environment plays an important role in determining foraging success. Most significantly, we found that feeding latencies in turbid conditions decreased significantly if visual landmarks were present. This demonstrates that zebrafish use visual landmark cues to navigate to foraging sites when visibility is impaired. This study has important implications on the role of behavioural plasticity and spatial learning in animals that allow them to cope with altered sensory environments such as episodes of enhanced turbidity that could be natural or anthropogenic.

Behavioural plasticity in a native species may be related to foraging resilience in the presence of an aggressive invader

2021 ◽  
Vol 17 (3) ◽  
Author(s):  
Melinda L. Keiller ◽  
Laura K. Lopez ◽  
Kai C. Paijmans ◽  
Marian Y. L. Wong
Keyword(s):  
Native Species ◽  
Foraging Efficiency ◽  
Behavioural Plasticity ◽  
Gambusia Holbrooki ◽  
Feeding Rates ◽  
Species Groups ◽  
Australian Fish ◽  
Mixed Species Groups ◽  
Social Behaviours

Competition between invasive and native species can result in the exploitation of resources by the invader, reducing foraging rates of natives. However, it is increasingly recognized that multiple factors can enhance the resilience of native species competing for limiting resources with invaders. Although extensively studied in terrestrial species, little research has focused on behavioural plasticity in aquatic ecosystems and how this influences native species resilience. Here, we examined the role of behavioural plasticity in interactions between a native Australian fish, Pseudomugil signifer, and a widespread invasive fish, Gambusia holbrooki . To determine whether P. signifer displays behavioural plasticity that may mitigate competition with G. holbrooki , we first quantified social behaviours (aggression, submission and affiliation) and shoal cohesion for each species in single- and mixed-species groups. Second, we compared the feeding rates of both species in these groups to ascertain if any modulation of social behaviours and cohesion related to foraging success. We found that aggressive and submissive behaviours of G. holbrooki and P. signifer showed plasticity in the presence of heterospecifics, but social affiliation, shoaling and, most importantly, foraging, remained inflexible. This variation in the degree of plasticity highlights the complexity of the behavioural response of a native species and suggests that both behavioural modulation and consistency may be related to sustaining foraging efficiency in the presence of an invader.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

1999 ◽  
Vol 81 (06) ◽  
pp. 951-956 ◽  
Author(s):  
J. Corral ◽  
R. González-Conejero ◽  
J. Rivera ◽  
F. Ortuño ◽  
P. Aparicio ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Cell Types ◽  
Receptor Expression ◽  
Case Control Studies ◽  
Platelet Surface ◽  
Vitro Analysis ◽  
And Function ◽  
In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

Von Willebrand disease and Weibel-Palade bodies

2010 ◽  
Vol 30 (03) ◽  
pp. 150-155 ◽  
Author(s):  
J. W. Wang ◽  
J. Eikenboom
Keyword(s):  
Platelet Adhesion ◽  
Coagulation Factor ◽  
Von Willebrand Disease ◽  
Inflammatory Factors ◽  
Limited Data ◽  
Storage Organelle ◽  
And Function ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryVon Willebrand factor (VWF) is a pivotal haemostatic protein mediating platelet adhesion to injured endothelium and carrying coagulation factor VIII (FVIII) in the circulation to protect it from premature clearance. Apart from the roles in haemostasis, VWF drives the formation of the endothelial cell specific Weibel-Palade bodies (WPBs), which serve as a regulated storage of VWF and other thrombotic and inflammatory factors. Defects in VWF could lead to the bleeding disorder von Willebrand disease (VWD).Extensive studies have shown that several mutations identified in VWD patients cause an intracellular retention of VWF. However, the effects of such mutations on the formation and function of its storage organelle are largely unknown. This review gives an overview on the role of VWF in WPB biogenesis and summarizes the limited data on the WPBs formed by VWD-causing mutant VWF.

Identifikasi Peran dan Strategi Pelabuhan Bebas Sabang

2020 ◽  
Vol 4 (3) ◽  
pp. 167-178
Author(s):  
Zurayna Sari
Keyword(s):  
Economic Development ◽  
Descriptive Analysis ◽  
Regional Growth ◽  
Maintenance Strategy ◽  
Regional Economic ◽  
Growth Center ◽  
Free Port ◽  
And Function ◽  
Role And Function

ABSTRAKPelabuhan berperan sebagai fasilitas penunjang pusat pertumbuhan regional dalam proses pembangunan ekonomi wilayah. Pelabuhan Bebas Sabang diarahkan sebagai pusat pertumbuhan ekonomi regional dan diharapkan dapat meningkatkan perekonomian Kawasan Sabang. Permasalahan yang dihadapi Pelabuhan Bebas Sabang adalah belum optimalnya peran dan fungsi Pelabuhan Bebas Sabang dalam menunjang perekonomian wilayah. Penelitian ini bertujuan untuk mengetahui peran Pelabuhan Bebas Sabang dalam mendorong perkembangan perekonomian Kawasan Sabang. Lingkup materi yang dibahas mencakup peran-peran Pelabuhan Bebas Sabang, menentukan potensi dan masalah serta upaya-upaya peningkatan peran Pelabuhan Bebas Sabang. Metode analisis yang dilakukan adalah analisis deskriptif dengan pendekatan analisis data kualitatif dan kuantitatif. Alat analisis yang digunakan adalah analisis SWOT IFAS-EFAS. Hasil analisis menunjukkan dalam kurun waktu 4 (empat) tahun terakhir dari tahun 2010-2013, Pelabuhan Bebas Sabang belum optimal dalam menjalankan perannya, sehingga membutuhkan strategi pengembangan dengan pendekatan Agressive Maintenance Strategy (strategi perbaikan agresif), yaitu strategi konsolidasi internal dengan memperbaiki faktor-faktor kelemahan untuk memaksimalkan pemanfaatan peluang.Kata kunci: Pengelolaan, SWOT IFAS-EFAS, WilayahABSTRACTPort was supporting facility of regional growth center in the process of regional economic development. Sabang free port was directed as the center of regional economic growth and expected to raise the economy of sabang. Problems faced by sabang free port was yet optimal role and function in supporting the economy of the region. This study aimed to determine the role of sabang free port in supporting the economic development of sabang. The covered material scope included roles of sabang free port, determining the potentials and problems and efforts of increasing the role of sabang free port. The method of analysis was descriptive analysis with qualitative and quantitative approach. The analytical tool used was the swot ifas-efas analysis. The analysis results showed in the period of 4 (four) years from 2010 until 2013, sabang free port was not optimal in carrying out its role yet, so it requires development strategies with agressive maintenance strategy approach, which is internal consolidation strategy by improving vulnerability factors to maximize the utilization of opportunities.Keywords:, Management, Regional, SWOT IFAS-EFAS

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