Methods of Assessing Quality of Aquatic Food

2020 ◽  
pp. 80-106
Author(s):  
G. Jeyasekaran ◽  
R. Jeya Shakila
Keyword(s):  
Aquatic Food

scholarly journals Seasonal status of density of phytoplanktons and zooplanktons in Gomti river of Lucknow (U.P.), India

2013 ◽  
Vol 5 (1) ◽  
pp. 58-62
Author(s):  
Preety Singh
Keyword(s):  
Monsoon Season ◽  
Winter Season ◽  
Pollution Level ◽  
Ecological Indicator ◽  
Biological Productivity ◽  
Gomti River ◽  
Aquatic Food Chain ◽  
Different Seasons ◽  
Aquatic Food

Biodiversity of river Gomti is heavily affected by pollution. Planktons are important biological parameters to access the pollution level. Zooplanktons are the source of food for higher organism and phytoplankton play important role in biosynthesis of organic material and influence the river ecosystem, aquatic food chain and water characteristic. The biological productivity as ecological indicator to identify the ecological quality of river Gomti. The phytoplankton density fluctuated maximum in between the range of (140-900 In/l) during monsoon season and minimum (40-140 In/l) during winter season. Zooplanktons were reported to be highest (168-220 In/l) during winter and lowest (114-155 In/l) during summer season. During study period the total of phytoplanktons (17 sp.) and zooplanktons (10 sp.) were noticed during different seasons. Present study concluded that seasonal differences of planktons density will help in further planning of water management and their use for beneficial purpose like agricultural, drinking for mankind.

Does Mixotrophy in ciliates compensate for poor-quality prey? Experiments with heterotrophic–mixotrophic species pairs

2019 ◽  
Vol 41 (5) ◽  
pp. 583-593
Author(s):  
Stephen A Wickham ◽  
Romana Wimmer
Keyword(s):  
Poor Quality ◽  
The Other ◽  
Large Role ◽  
Limited Ability ◽  
Species Pairs ◽  
Aquatic Food ◽  
Alternate Source ◽  
Small Advantage ◽  
Mixotrophic Ciliates

Abstract Fatty acid and sterol profiles play a large role in determining the food quality of prey in aquatic food webs. Ciliates have limited ability to synthesize essential polyunsaturated fatty acids (PUFA) and sterols, and must obtain these from their food. Many mixotrophic ciliates, however, are in a symbiosis with Chlorella, and this may compensate for prey that is low in PUFA and sterols. Moreover, when PUFA-rich prey are P-limited, mixotrophs may be less dependent than heterotrophs on having the optimal mixture of PUFA-rich and P-rich prey. To test these hypotheses, experiments were conducted using heterotrophic-mixotrophic species pairs and prey mixes with varying proportions of good and poor quality prey. Prey proportions had clear effects on ciliate growth rates, often with a clear threshold. In only one species, however, did mixotrophy appeared to be advantageous, with growth independent of the proportion of PUFA-rich prey. In the other two species pairs, mixotrophy gave at best a small advantage over heterotrophy when there was a large proportion of PUFA-poor prey, independent of whether the PUFA-rich prey was P-limited or P-replete. While PUFA- and sterol-rich prey are important for heterotrophic ciliates, mixotrophy cannot be universally employed as an alternate source of these required nutrients.

Quality of Aquatic Food

2020 ◽  
pp. 4-15
Author(s):  
G. Jeyasekaran ◽  
R. Jeya Shakila
Keyword(s):  
Aquatic Food

A comparative evaluation of the nutritional quality of Eriocheir sinensis and Eriocheir japonica (Brachyura, Varunidae)

Crustaceana ◽  
2020 ◽  
Vol 93 (6) ◽  
pp. 567-585
Author(s):  
Zhiyan Wang ◽  
Lu Zu ◽  
Qingqing Li ◽  
Xiaodong Jiang ◽  
Wengang Xu ◽  
...  
Keyword(s):  
Proximate Composition ◽  
Nutritional Quality ◽  
Essential Amino Acids ◽  
Eriocheir Sinensis ◽  
Omega 3 ◽  
Important Species ◽  
Mitten Crab ◽  
Eriocheir Japonica ◽  
Aquatic Food

Abstract The Japanese mitten crab Eriocheir japonica is an economically important species widely distributed throughout the East Asia region, but information on the compositional characteristics and nutritional quality of E. japonica is still scarce. Thus, this study was conducted to compare the edible tissue indices, proximate composition, fatty acid profiles and amino acid contents between wild E. sinensis and E. japonica. It showed that: (1) both E. sinensis and E. japonica have a high total edible yield (approximately 40%); (2) E. sinensis and E. japonica have a similar proximate composition, except for total lipids; (3) female E. japonica have higher percentages of C18:3n3, C20:5n3 and C22:6n3; (4) E. sinensis have higher levels of essential amino acids than E. japonica in muscle. In conclusion, these results demonstrated that wild E. japonica is rich in omega-3 fatty acids, and both E. sinensis and E. japonica are aquatic food of high nutritional value, with a high edible yield.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

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