Presence Of Compartments Research Articles

Cryobanking of Fish and Shellfish Egg, Embryos and Larvae: An Overview

Number of attempts has been made to cryopreserve fish and shellfish gametes and success has been achieved to establish only sperm banks in case of some commercially important fish. In shellfish also particularly in shrimps though the sperm cryopreservation was successful, no attempts were made to develop sperm banks. As far as cryobanking of egg and embryos of fish and shellfish is concerned, less research efforts were made that too with limited success. Number of reasons has been given for the failure of egg /embryo cryopreservation and the main barriers speculated are low membrane permeability in the eggs, and the large yolk mass of the oocyte and the presence of compartments in early developing embryos. Both these factors result in ice crystal formation during the freezing process. In addition, the oocytes and embryos are prone to chilling injuries unrelated to ice crystal damage. There are number of other problems reported by several workers in the egg/embryo cryobanking protocols which are elaborately discussed in the present paper. There is an urgent need to develop a viable cryobanking technology for fish egg/embryos to enhance fish production in captive condition. Attempt to cryopreserve larvae of aquatic animals is another challenge coming up in recent past. The purpose of the present review is to collect comprehensive information on the efforts so far made on fish and shellfish egg and embryo cryobanking, assess the challenges in the development of viable technology and plan for future research for making this technology viable and cost effective.

Thin-Walled Cavitary Lung Adenocarcinoma: A Rare Unusual Case

: Thin-walled cavitary lung adenocarcinoma is not common. When cavitary lung cancer was classified as a histologic subtype, squamous cell carcinoma was the most common, followed by adenocarcinoma and finally large cell carcinoma. Cavitation was not found in small cell lung cancer. Some cases of thin-walled cavitary lung adenocarcinoma have been reported. Thin-walled cavitary lung cancer can be detected by the following radiological signs: irregular thickening of the cavity wall, wall nodule formation, the presence of compartments in the cavity, increased standard uptake values (SUVs) on positron emission tomography (PET). A thin‑walled cavity accompanied by mediastinal lymph node or distant metastasis, or enlargement of the lesion on long term follow-up. We report on a case of thin walled cavitary lung cancer whose cavity tended to enlarge during a 10-month follow-up, but no other evidence of imaging finding indicated potential lung cancer. It suggests that the unidirectional check-valve mechanism could make enlarging thin walled cavitary lesion due to lepidic growth pattern.

Can biological structures be natural and sustainable capsules?

Flavor and fragrance molecules are used in many industrial fields such as food, cosmetics, tissues, pharmacy, agriculture (pheromones) etc. As most actives have a specific target and are fragile molecules, encapsulation processes have been developed for their use. These technologies are efficient to avoid loss of actives, dissemination out of the target and subsequent pollution, and to protect molecules up to their target. Several processes have been developed responding to the numerous situations encountered (e.g., protection against air, temperature, light, pH; masking or revealing sensorial properties of the molecule; release during the process, in the plate, in the mouth, etc.). However, the general trend for natural products and for processes friendly for the environment has put forward several constraints. According to the various regulations (CFR 1990, CE 1334/2008 etc.), to be natural, a product has to come from plant or animal raw materials with only a physical, enzymatic or microbial process at the exclusion of any chemical step. This definition results from a consensus between jurists, philosophers, industry, consumers, politics etc. It must be noted that this concept of naturality is neither universal nor consensual. In philosophy, although defined by Aristotle in his Book II as one thing that has “within itself a principle of motion and of stationariness,” natural things are not always easy to recognize from their opposite, artifactual things. With the completed and extended definition of artifactual things to what has been done in a project or purpose [discussed by J. Monod in the introduction of “Chance and necessity” (1971)], agriculture and biotechnology products would become mainly artifactual. This concept of naturality is thus quite controversial and regulation may evolve in the future. However, despite the fact that many definitions are hidden behind the word of naturality, this concept has attracted consumers, first in Germanic countries in the 1980s, spreading over Europe, then to North America, and from there to the whole World. The demand for natural product first appeared in food, reached cosmetics recently and is now expanding to other fields. However, to keep the label, natural flavors and fragrances require natural capsules, i.e., capsules coming from natural materials that have not been modified through chemical steps. As a result, the issue of naturality is closely related to the sustainability of the process, i.e., its impact on the environment (release of solvents, carbon impact etc.), which is also getting more and more important. In the field of encapsulation, among the numerous technologies developed at the lab scale, just few are ready for industrial implementation and it is often difficult to obtain an up-scalable process without any use of toxic solvents or not-natural materials. These technologies are based on various principles often trying to polymerise and coat a suspension of active. One could notice however that the presence of compartments has been a prerequisite to evolution and natural capsules have thus been developed from the apparition of the first cell. Among biological structures, cells are indeed a good protection for actives that have to interact together and with the environment. When the protection needs to be stronger and fewer relations are required between actives and the environment, specific structures are produced like microbial spores. Eventually, specialized structures are able to disseminate actives in the environment like pollen grains. With such nice model systems, humanity has developed biomimetics to synthesize efficient artificial capsules (Cai et al., 2015) but tries also to use already existing natural capsules (Pham-Hoang et al., 2013). Although several works have been carried out on this subject and some products have been developed from years, these natural capsules are difficult to utilize, precisely because of their envelope properties (Table ​(Table1).1). Indeed, the envelope, that makes the active protected inside the cell, is difficult to cross in a controlled way, making loading and controlled release difficult. Industrial encapsulation in these natural structures might also be difficult to carry out in a fully natural and sustainable process. In this opinion article, we propose to discuss the utilization of biological structure as microcapsules for natural and sustainable odorant products. Table 1 Performances of various biological structures as natural capsules.

C-18: Zebrafish cryobiology: Sperm, oocytes, embryos and stem cells

Cryopreservation is a proven method for long-term maintenance of genetic material, nevertheless current protocols for fish are not standardized and yield inconsistent results, threatening the efficacy of large-scale genetic screening and stock centers. Previous reports have dealt with sperm cryopreservation in >200 fish species from marine and freshwater species with the most common observation from these publications being the inconsistency in the post-thaw results. Consortia are working to identify processes in zebrafish protocols to try and improve post-thaw variability. Although a great deal of work has been done examining the cryobiology of zebrafish oocytes at various stages of maturation, the successful cryopreservation, maturation and subsequent fertilization of these oocytes has not been proven. Similarly, zebrafish embryo cryopreservation has been extensively examined for the past 25 years, and several aspects of standard cryopreservation methods have made it a challenging system to develop successful protocols for. These problems include: (1) a large overall size resulting in a low surface to volume ratio that can slow water cryoprotectant efflux and influx; (2) the presence of compartments, such as the blastoderm and yolk; with different permeability properties, (3) susceptibility to chilling injury; and (4) extreme chilling sensitivity at early relatively undifferentiated developmental stages necessitating vitrification. New laser-warming protocols may help change how we understand this complex suite of challenges in zebrafish embryo cryopreservation, especially the relative need for cryoprotectant and the potential for prevention of damaging intracellular ice crystal formation. To diversify and expand our resource collections, however, cryopreserved zebrafish spermatogonial stem cells may provide one of the most important strategies for resource centers. Researchers have successfully developed simple effective cryopreservation methods for zebrafish testes, allowing the rapid and effective preservation of mutant and transgenic lines.

Drosophila embryo syncytial blastoderm cellular architecture and morphogen gradient dynamics: Is there a correlation?

During embryo development in many metazoan animals, the first differentiated cell type to form is an epithelial cell. This epithelial layer is modified by developmental cues of body axes formation to give rise to various tissues. The cells that arise are mesenchymal in nature and are a source of other tissue types. This epithelial to mesenchymal transition is used for tissue type formation and also seen in diseases such as cancer. Here we discuss recent findings on the cellular architecture formation in the Drosophila embryo and how it affects the developmental program of body axes formation. In particular these studies suggest the presence of compartments around each nucleus in a common syncytium. Despite the absence of plasma membrane boundaries, each nucleus not only has its own endoplasmic reticulum and Golgi complex but also its own compartmentalized plasma membrane domain above it. This architecture is potentially essential for morphogen gradient restriction in the syncytial Drosophila embryo. We discuss various properties of the dorso-ventral and the antero-posterior morphogen gradients in the Drosophila syncytium, which are likely to depend on the syncytial architecture of the embryo.

Variation in fluid contacts in the Azeri field, Azerbaijan: sealing faults or hydrodynamic aquifer?

Abstract The Azeri field in the South Caspian Sea, offshore Azerbaijan, is a periclinal anticline 20 km in length containing multiple stacked reservoirs of Pliocene age. Appraisal wells that were drilled at the eastern end of the structure identified multiple oil–water contacts and fluid pressure gradients in both of the principal reservoirs, the Pereriv B and D. At the time, these data were interpreted to indicate the presence of compartments at the eastern end of the field as a result of sealing faults within the aquifer. This local compartmentalization seemed to be in marked difference to the majority of the field where pressure connectivity had been observed. A new analysis of the pressure data for the Pereriv B shows that aquifer pressures at sea‐level datum define a simple water potential gradient. As a result of this, the oil–water contact in this reservoir is gently inclined towards the NNE. The precise inclination and orientation of the oil–water contact has been determined geometrically using the depths and coordinates of free-water levels and oil–water contacts from around the field. The best-fit inclined oil–water contact for the Pereriv B also provides a good fit to the contact observed from seismic amplitudes. The new analysis provides a more optimistic view of reservoir connectivity, and the conceptual geological model for the eastern end of the field is now consistent with observations made in the rest of the Azeri field.

Reservoir compartmentalization: get it before it gets you

Abstract This paper examines the impact of compartmentalization on oil recovery, the importance of identifying it during field appraisal, and methods to evaluate it using fluid data. The impact on recovery factor is highlighted using a global database of oil field recovery factors as a function of reservoir complexity and compartmentalization, and emphasized in two case studies. The effect of compartmentalization on oil recovery demonstrates the benefit in characterizing compartmentalization correctly during appraisal, so that the field can be developed in an optimal manner. Early characterization of field compartmentalization requires making maximum use of available fluid data during appraisal. When interpreting fluid data to identify compartmentalization, it is critical to take into account the different time-scales for various fluid signals (pressure, contacts, density, composition) to equilibrate, and to be able to extrapolate to field production time-scales. This is essential to avoid false negatives (compartments assumed absent due to homogeneous fluid properties, when in fact fluids would have equilibrated even in the presence of compartments), false positives (where fluid differences are interpreted as evidence of compartments when in fact there has not been sufficient time for equilibration to occur), and to resolve apparently conflicting data (some fluid indicators are at equilibrium, others are not). Rigorous simulation of fluid equilibration is a complex multiphase multidimensional process, and is generally reserved for specialist in-depth studies. However, order-of-magnitude evaluations can be made using analytical solutions in minutes, allowing many ‘what-if’ scenarios to be considered and uncertainty to be assessed. Analytical solutions for estimating the time required for spatially-varying fluid properties to revert to steady state distributions are reviewed. All these mixing processes are shown to be diffusive in character. An effective diffusion coefficient for each process can be calculated from the reservoir rock and fluid properties. For an isothermal system, the different time-scales and distances for each fluid‐property variation to attain equilibrium can be compared on a single graph. Where the time elapsed since fluid‐perturbation is known, analytical solutions can be used to estimate the degree of compartmentalization (e.g. permeability of barriers). These solutions lend themselves to the development of simple practical compartment-assessment tools for industry practitioners.

Occurrence of structures with lysosome-like function in plant cells.

EVIDENCE for the existence of bodies with a lysosome-like function in plant cells has been discussed by Gahan1. He and Maple observed that the terminal stage of xylem differentiation in root tips is accompanied by a change from a particulate to a diffuse distribution of acid phosphatase2. Sievers3 in an electron microscopic study of the rhizoid cells of Chara observed the presence of compartments in the cytoplasm containing what appeared to be the remains of various organelles. He concluded that these structures have a function analogous to the lysosomes of animal cells.