Life cycle assessment of aquaculture systems—a review of methodologies

Purpose  

As capture fishery production has reached its limits and global demand for aquatic products is still increasing, aquaculture has become the world’s fastest growing animal production sector. In attempts to evaluate the environmental consequences of this rapid expansion, life cycle assessment (LCA) has become a frequently used method. The present review of current peer-reviewed literature focusing on LCA of aquaculture systems is intended to clarify the methodological choices made, identify possible data gaps, and provide recommendations for future development within this field of research. The results of this review will also serve as a start-up activity of the EU FP7 SEAT (Sustaining Ethical Aquaculture Trade) project, which aims to perform several LCA studies on aquaculture systems in Asia over the next few years.     

N-terminal modification of proteins—a review

The first efforts to modify the terminal α-amino groups of proteins without reaction of the ?-amino groups of lysine residues made use of their lower pK values. A pH below 7 favors modification of weaker bases, since the stronger bases, although more reactive, are protected to an even greater extent by protonation. Unfortunately, this approach only favors modification of terminal over side-chain amino groups to a limited extent. N-Terminal serine and threonine residues may be selectively acylated on the amino group by an acyl transfer reaction after a peptide has been selectively acylated on its hydroxyl groups. This approach is severely limited by the need for the peptide to be stable to the acidic and anhydrous conditions necessary for selective O-acylation, and to the alkaline conditions necessary for removing the remaining O-acyl groups. Terminal serine and threonine residues may also be selectively oxidized by periodate, since this reaction is a thousand-fold faster than other oxidations of periodate, e.g., of 1,2-diols or disulfides. Further, it forms glyoxyloyl groups, which may be converted into terminal glycine residues by transamination. The last observation provided the basis for the one general modification of N-terminal residues, namely their conversion into 2-oxoacyl groups by reaction of the α-amino group with glyoxylate, a reaction catalysed by a bivalent cation, e.g., Cu²⁺, and a base, e.g., acetate. Participation of the neighboring peptide bond in the reaction ensures specificity of the reaction for the N-terminus. Scission of the N-terminal residue is possible after such a transamination; hence residues may be removed from the N-terminus under nondenaturing conditions. Other exploitations of transamination may be developed.     

Genetic toxicology of vinyl chloride—a review

Vinyl chloride (VC) is a colorless gas with a mild, sweet odor. It is extensively used in the production of vinyl chloride polymer, copolymer resin, packaging materials, wire and cable coatings as well as in industrial and laboratory intermediates. It is toxic and also carcinogenic in experimental animals. The wide human exposure to this compound in different industries throughout the world causes great concern for human health. In the present review an attempt has been made to evaluate and update the genotoxic effects of vinyl chloride based on the available literature.     

Mesozoic birds of China—a synoptic review

A synoptic review of the discoveries and studies of Chinese Mesozoic birds is provided in this paper. ⁴⁰Ar/³⁹Ar dating of several bird-bearing deposits in the Jehol Group has established a geochronological framework for the study of the early avian radiation. Chinese Mesozoic birds had lasted for at least 11 Ma during about 131 Ma and 120 Ma (Barremian to Aptian) of the middle and late Early Cretaceous, respectively. In order to further evaluate the change of the avian diversity in the Jehol Biota, six new orders and families are erected based on known genera and species, which brings the total number of orders of Chinese Mesozoic birds to 15 and highlights a remarkable radiation ever since the first appearance of birds in the Late Jurassic. Chinese Early Cretaceous birds had experienced a significant differentiation in morphology, flight, diet and habitat. Further examination of the foot of Jeholornis suggests this bird might not have possessed a fully reversed hallux. However, the attachment of metatarsal I to the medial side of metatarsal II does not preclude trunk climbing, a pre-adaptation for well developed perching life of early birds. Arboreality had proved to be a key adaptation in the origin and early evolution of bird flight, and the adaptation to lakeshore environment had played an equally important role in the origin of ornithurine birds and their near-modern flight skill. Many Chinese Early Cretaceous birds had preserved the direct evidence of their diet, showing that the most primitive birds were probably mainly insectivorous and that specialized herbivorous or carnivorous (e.g., piscivorous) dietary adaptation had appeared only in later advanced forms. The only known Early Cretaceous bird embryo fossil has shown that precocial birds had occurred prior to altricial birds in avian history, and the size of the embryo and other analysis indicate it probably had a short incubation period. Leg feathers probably have a wide range of distribution in early birds, further suggesting that leg feathers had played a key role in the beginning stage of the flight of birds. Finally, the Early Cretaceous avian radiation can be better understood against the background of their unique ecosystem. The advantage of birds in the competitions with other vertebrate groups such as pterosaurs had probably not only resulted in the rapid differentiation and radiation of birds but also the worldwide spreading of pterosaurs and other vertebrates from East Asia in the Early Cretaceous. Selected from Vertebrata PalAsiatica 2006, 44 (1): 74–98     

Compactin—a review

Compactin, a hypocholesterolemic molecule, is a competitive inhibitor of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase, which is a regulatory enzyme for cholesterol biosynthesis. The structural similarity and high affinity of the acid form of compactin and HMG, the natural substrate of enzyme, results in specific and effective inhibition of this enzyme. Inhibition results in reduced levels of mevalonic acid in the body, leading to pleiotropic effects. Various fungi have been used for the commercial production of compactin. Using different strategies for improving production levels, yields have been increased to around 900 times of the amount originally produced. Recently, the gene sequence responsible for compactin production has been cloned and sequenced. This review deals with the chemistry, mode of action, pharmacology, biosynthesis, and production of compactin. A comparative study of various reports dealing with the production of compactin is also included.     

Oligochaeta of the Danube River — a faunistical review

The aim of this work is to discuss the distribution of Oligochaeta (Annelida) in the Danube River using the collections made by the Joint Danube Survey 2007 (JDS2) on more than 2800 km of the river. The basic faunistical features of the oligochaete assemblages were analysed with regard to three main sectors of the Danube (upper, middle and lower reaches, the last with the Danube Delta). A total of 52 oligochaete taxa have been recorded. Most of the observed species are typical of the potamon-type rivers in the region, and are well adapted to moderate-to-high organic load. The highest taxa richness and frequency of occurrence were observed among the Tubificidae family. Naididae, Propappidae, Enchytraeidae and Haplotaxidae had also low frequency. The upper reach of the Danube showed the lowest species richness, while the middle reach is characterised by its highest species richness. Construction of dams and regulation of the riverbed have resulted in an increase of limno(rheo)philic taxa which prefer slow-flowing and lentic zones.     

Heterologous expression of alkaloid biosynthetic genes — a review

Tetrahydrobenzylisoquinoline alkaloids comprise a diverse class of secondary metabolites with many pharmacologically active members. The biosynthesis at the enzyme level of at least two tetrahydrobenzylisoquinoline alkaloids, the benzophenanthridine alkaloid sanguinarine in the California poppy, Eschscholtzia californica, and the bisbenzylisoquinoline alkaloid berbamunine in barberry, Berberis stolonifera, has been elucidated in detail starting from the aromatic amino acid (aa) l-tyrosine. In an initial attempt to develop alternate systems for the production of medicinally important alkaloids, one enzyme from each pathway (BBE, a covalently flavinylated enzyme of benzophenanthridine alkaloid biosynthesis and CYP80, a phenol coupling cytochrome P-450-dependent oxidase of bisbenzylisoquinoline alkaloid biosynthesis) has been purified to homogeneity, a partial aa sequence determined, and the corresponding cDNAs isolated with aid of synthetic oligos based on the aa sequences. The recombinant enzymes were actively expressed in Spodoptera frugiperda Sf9 cells using a baculovirus vector, purified and then characterized. Insect cell culture has proven to be a powerful system for the overexpression of alkaloid biosynthetic genes.     

16. Dispersal of freshwater algae — a review

A survey is given on the various methods for dispersal of freshwater algae. Dispersal factors are either water or air, or organisms — from beetles, dragonflies and mammals to birds, the latter being the most important group. The question of dispersal distances is discussed, in relation to dispersal mechanisms and to the resistance of the algae to transport conditions. Man's recent importance in algal dispersal is emphasized.     

Regulation and expression of transgenes in fish—a review

Transgenic fish, owing to a number of advantages which they offer over other species, are proving to be valuable model systems for the study of gene regulation and developmental genetics in addition to being useful targets for the genetic manipulation of commercially important traits. Despite having begun only a decade ago, the production of transgenic fish has become commonplace in a number of laboratories world-wide and considerable progress has been made. In this review, we initially consider the various regulatory elements and coding genes which have been used in fish, and subsequently discuss and compare both the transient and long-term fate and expression patterns of injected DNA sequences in the context of the different factors which are likely to have an effect on the expression of transgenes.     

High-altitude vegetation of the Western Carpathians — a syntaxonomical review

This paper presents a survey of high-altitude plant communities which occur in the Western Carpathians with an enumeration of the characteristic, transgressive and differential species of the individual alliances, orders and classes. It describes the tall-herb vegetation (Mulgedio-Aconitetea) and communities of the subalpine shrubs (Betulo carpaticae-Alnetea viridis), the montane and alpine calcareous swards (Elyno-Seslerietea), the wind-exposed cryophilous swards on ridge edges with low snow cover (Carici rupestris-Kobresietea bellardii), the chionophilous communities of snow beds and snow fields (Salicetea herbaceae), the arctic-boreal dwarf-shrub heathlands (Loiseleurio-Vaccinietea), the alpine acidophilous grasslands (Caricetea curvulae) and the high-mountain mat-grass swards of the alliance Nardion strictae (Nardetea strictae).     

Flashback and foreshadowing—a review of the taxon Opisthobranchia

Opisthobranchia have experienced an unsettled taxonomic history. At the moment their taxonomy is in state of dramatic flux as recent phylogenetic studies have revealed traditional Opisthobranchia to be paraphyletic or even polyphyletic, allocating some traditional opisthobranch taxa to other groups of Heterobranchia, e.g. Pulmonata. Here we review the history of Opisthobranchia and their subgroups, explain their traditionally proposed relationships, and outline the most recent phylogenetic analyses based on various methods (morphology, single gene and multiple gene analyses, as well as genomic data). We also present a phylogenetic hypothesis on Heterobranchia that, according to the latest results, represents a consensus and is the most probable one available to date. The proposed phylogeny supports the Acteonoidea outside of monophyletic Euthyneura, the basal euthyneuran split into Nudipleura (Nudibranchia plus Pleurobranchoidea) and the recently established taxon Tectipleura. The latter divides into the Euopisthobranchia, containing most of the major traditional opisthobranch clades, and the Panpulmonata, with a mix of the former opisthobranch, putative allogastropod and pulmonate taxa. This “new euthyneuran tree” rejects the traditional taxa Opisthobranchia and Pulmonata, and, in particular, has profound implications for preconceived textbook scenarios of opisthobranch and pulmonate evolution, which must now be reconsidered. In the absence of systematic barriers, research communities—which have traditionally investigated marine and non-marine heterobranchs separately—need to interact and finally merge for the sake of science.     

The effects of mechanically-induced stress in plants — a review

Mechanically-induced stress (MIS) occurs naturally in plants as the aerial parts are moved, usually by wind, but also by such agents as rain and animals. It can be induced indoors by various actions such as rubbing or bending the stem or shaking or brushing the entire shoot. The most noticeable effect of MIS is a reduction in stem, leaf or petiole length invariably resulting in plants which are smaller and more compact than unstressed controls. However, the response of other variables can often differ between species and there may be either increases or decreases in stem or petiole diameter, root: shoot weight ratio, chlorophyll content or drought resistance. Why species should differ in this way, and what is the endogenous control mechanism for MIS responses, are inanswered questions. Ethylene, which increases as a result of MIS in several species may cause some MIS responses such as increased stem diameter, epinasty or a change in sex expression. However, evidence suggests that MIS retardation of extension growth may equally be due to lower or supraoptimal auxin levels or lower gibberellin levels.The uses in the field of the growth promoter gibberellin or the growth retardant chlormequat chloride (CCC) appear to be examples of respectively reversing or stimulating MIS growth response. MIS may be applied indoors if short compact plants are needed, either for aesthetic purposes as with floral crops, or if hardier and more manageable plants are needed, such as seedlings for transplanting in the field. Much more research is needed to estimate the importance of MIS in the field and to assess how such knowledge may be used to improve crop yield.     

Environmental impacts of hybrid and electric vehicles—a review

Purpose

A literature review is undertaken to understand how well existing studies of the environmental impacts of hybrid and electric vehicles (EV) address the full life cycle of these technologies. Results of studies are synthesized to compare the global warming potential (GWP) of different EV and internal combustion engine vehicle (ICEV) options. Other impacts are compared; however, data availability limits the extent to which this could be accomplished.

Method

We define what should be included in a complete, state-of-the-art environmental assessment of hybrid and electric vehicles considering components and life cycle stages, emission categories, impact categories, and resource use and compare the content of 51 environmental assessments of hybrid and electric vehicles to our definition. Impact assessment results associated with full life cycle inventories (LCI) are compared for GWP as well as emissions of other pollutants. GWP results by life cycle stage and key parameters are extracted and used to perform a meta-analysis quantifying the impacts of vehicle options.

Results

Few studies provide a full LCI for EVs together with assessment of multiple impacts. Research has focused on well to wheel studies comparing fossil fuel and electricity use as the use phase has been seen to dominate the life cycle of vehicles. Only very recently have studies begun to better address production impacts. Apart from batteries, very few studies provide transparent LCIs of other key EV drivetrain components. Estimates of EV energy use in the literature span a wide range, 0.10?C0.24?kWh/km. Similarly, battery and vehicle lifetime plays an important role in results, yet lifetime assumptions range between 150,000?C300,000?km. CO₂ and GWP are the most frequently reported results. Compiled results suggest the GWP of EVs powered by coal electricity falls between small and large conventional vehicles while EVs powered by natural gas or low-carbon energy sources perform better than the most efficient ICEVs. EV results in regions dependant on coal electricity demonstrated a trend toward increased SO _x emissions compared to fuel use by ICEVs.

Conclusions

Moving forward research should focus on providing consensus around a transparent inventory for production of electric vehicles, appropriate electricity grid mix assumptions, the implications of EV adoption on the existing grid, and means of comparing vehicle on the basis of common driving and charging patterns. Although EVs appear to demonstrate decreases in GWP compared to conventional ICEVs, high efficiency ICEVs and grid-independent hybrid electric vehicles perform better than EVs using coal-fired electricity.     

Brucellosis in India — a review

Brucellosis is an important re-emerging zoonosis with a worldwide distribution. It is still an uncontrolled serious public health problem in many developing countries including India. Brucellosis in India is yet a very common but often neglected disease. Currently, Brucella melitensis accounts for most recorded cases globally with cattle emerging as a important reservoir with the few cases of B. suis. Isolated cases of non-terrestrial brucellosis and continuing transmission from wild animals have raised important epidemiological issues. Routine serological surveillance along with high clinical suspicion and screening of family members of index cases would be essential in delineating the real magnitude of human brucellosis in endemic countries. Increased business and leisure travel to endemic countries have led to diagnostic challenge in non-endemic areas. Laboratory testing is indispensable for diagnosis. Advances in newer rapid, sensitive, and specific testing methodologies and alternate treatment strategies are urgently needed. A safe and effective vaccine in human is not yet available. Prevention is dependent upon increasing public awareness through health education programmes and safe livestock practices. Active co-operation between health and veterinary services should be promoted. This review collates world literature and its impact to the discovery, isolation and diagnosis and epidemiology along with the control measures adapted in the Indian scenario.     

Control of fermenters – a review

Fermenter control has been an active area of research and has attracted more attention in recent years. This is due to the new developments in other related areas which can be exploited to overcome the inherent difficulties in fermenter control. Beginning with conventional regulatory control of operating variables such as temperature, pH and dissolved oxygen concentration, research in fermenter control has undergone significant changes including the recent neural network based approaches. The objective of the paper is to focus the attention of the researchers to the developments in the control of batch, fed-batch and continuous fermenters over the past few years.     

Translation attenuation regulation of chloramphenicol resistance in bacteria — a review

The chloramphenicol (Cm)-inducible cat and cmlA genes are regulated by translation attenuation, a regulatory device that modulates mRNA translation. In this form of gene regulation, translation of the Cm^R coding sequence is prevented by mRNA secondary structure that sequesters its ribosome-binding site (RBS). A translated leader of nine codons precedes the secondary structure, and induction results when a ribosome becomes stalled at a specific site in the leader. Here we demonstrate that the site of ribosome stalling in the leader is selected by a cis effect of the nascent leader peptide on its translating ribosome.     

Conversion of native terrestrial ecosystems in Hawai‘i to novel grazing systems: a review

The remote oceanic islands of Hawai‘i exemplify the transformative effects that non-native herbivorous mammals can bring to isolated terrestrial ecosystems. We reviewed published literature containing systematically collected, analyzed, and peer-reviewed original data specifically addressing direct effects of non-native hoofed mammals (ungulates) on terrestrial ecosystems, and indirect effects and interactions on ecosystem processes in Hawai‘i. The effects of ungulates on native vegetation and ecosystems were addressed in 58 original studies and mostly showed strong short-term regeneration of dominant native trees and understory ferns after ungulate removal, but unassisted recovery was dependent on the extent of previous degradation. Ungulates were associated with herbivory, bark-stripping, disturbance by hoof action, soil erosion, enhanced nutrient cycling from the interaction of herbivory and grasses, and increased pyrogenicity and competition between native plants and pasture grasses. No studies demonstrated that ungulates benefitted native ecosystems except in short-term fire-risk reduction. However, non-native plants became problematic and continued to proliferate after release from herbivory, including at least 11 species of non-native pasture grasses that had become established prior to ungulate removal. Competition from non-native grasses inhibited native species regeneration where degradation was extensive. These processes have created novel grazing systems which, in some cases, have irreversibly altered Hawaii’s terrestrial ecology. Non-native plant control and outplanting of rarer native species will be necessary for recovery where degradation has been extensive. Lack of unassisted recovery in some locations should not be construed as a reason to not attempt restoration of other ecosystems.     

Design of a Zinc-Finger Hydrolase with a Synthetic αββ Protein

Recent advances in protein design have opened avenues for the creation of artificial enzymes needed for biotechnological and pharmaceutical applications. However, designing efficient enzymes remains an unrealized ambition, as the design must incorporate a catalytic apparatus specific for the desired reaction. Here we present a de novo design approach to evolve a minimal carbonic anhydrase mimic. We followed a step-by-step design of first folding the main chain followed by sequence variation for substrate binding and catalysis. To optimize the fold, we designed an αββ protein based on a Zn-finger. We then inverse-designed the sequences to provide stability to the fold along with flexibility of linker regions to optimize Zn binding and substrate hydrolysis. The resultant peptides were synthesized and assessed for Zn and substrate binding affinity by fluorescence and ITC followed by evaluation of catalytic efficiency with UV-based enzyme kinetic assays. We were successful in mimicking carbonic anhydrase activity in a peptide of twenty two residues, using p-nitrophenyl acetate as a CO₂ surrogate. Although our design had modest activity, being a simple structure is an advantage for further improvement in efficiency. Our approach opens a way forward to evolving an efficient biocatalyst for any industrial reaction of interest.     

B chromosomes in angiosperm—a review

A review article on B chromosomes (Bs) in angiosperms is documented considering occurrence, morphology, polymorphic B forms, divisional phase heterogeneity, chromatin organization and gene content, sequence composition, origin, evolutionary aspects and significant role on host with an objective to foresee the evolutionary perspectives as it still remains an enigma. Irrespective of the origin of Bs, it seems that they have attained the following modifications, namely, insertion of centromeric and telomeric sequences, structural reorganization and procuring mitotic and meiotic drives but shows genetic inertness and present in the host as selfish DNA. In the context, few questions are raised. Further, scientific quest may unravel the unexplored information about Bs to ascertain its evolutionary perspectives, if any.