Alterations in the hepatic enzymes following experimental lead poisoning

An investigation on the influence of lead toxicity on some of the hepatic enzymes was studied in rats both after a shorter interval of 15 d and after longer intervals of 60 and 90 d. Three different doses of lead as 5, 10, and 50 mg/kg body wt were administered orally on every alternate day. Whereas significant inhibition of succinic dehydrogenase was seen following lead poisoning, the activity acid and alkaline phosphatase increased with lead intoxication. The histoarchitecture of the liver was grossly intact. Liver accumulated less lead compared to kidney at 60 and 90 d.     

SNaPe: a versatile method to generate multiplexed protein fusions using synthetic linker peptides for in vitro applications

Understanding the structure and function of protein complexes and multi‐domain proteins is highly important in biology, although the in vitro characterization of these systems is often complicated by their size or the transient nature of protein/protein interactions. To assist in the characterization of such protein complexes, we have developed a modular approach to fusion protein generation that relies upon S ortase‐mediated and Na tive chemical ligation using synthetic Pe ptide linkers (SNaPe) to link two separately expressed proteins. In this approach, we utilize two separate linking steps – sortase‐mediated and native chemical ligation – together with a library of peptide linkers to generate libraries of fusion proteins. We have demonstrated the viability of SNaPe to generate libraries from fusion protein constructs taken from the biosynthetic enzymes responsible for late stage aglycone assembly during glycopeptide antibiotic biosynthesis. Crucially, SNaPe was able to generate fusion proteins that are inaccessible via direct expression of the fusion construct itself. This highlights the advantages of SNaPe to not only access fusion proteins that have been previously unavailable for biochemical and structural characterization but also to do so in a manner that enables the linker itself to be controlled as an experimental parameter of fusion protein generation. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.     

Description of the digestive tract and feeding habits of the king angelfish and the Cortes angelfish

Morphologically, the digestive tracts of the king angelfish Holacunthus passer and the Cortes angelfish Pomacanthus zonipectus are similar, yet the king angelfish intestine is almost 30% longer than that of the Cortes angelfish. Both pomacanthids have a small mouth with villiform teeth, a short oesophagus, a well-defined stomach, and a terminal sac at the end of the digestive tract. The terminal sac, the acid pH in the stomach, and the long intestine may facilitate efficient use of seaweed nutrients. Stomach contents were analysed to determine diets and interspecific overlap. Seventy-one species were found in the stomachs of the king angelfish and 53 in the stomachs of the Cortes angelfish. Because of the wide range of species in their diets, both angelfish must be regarded as omnivorous. The most frequent foods were seaweed and sponges, but for the king angelfish, crustaceans were also important. A cluster analysis was done to determine whether the diets of these fish were similar by sex, size, or season. No similarities were found. Dietary overlap is high in relation to other pomacanthids.     

Evolutionary analysis of a novel zinc ribbon in the N-terminal region of threonine synthase

Threonine synthase (TS) catalyzes the terminal reaction in the biosynthetic pathway of threonine and requires pyridoxal phosphate as a cofactor. TSs share a common catalytic domain with other fold type II PALP dependent enzymes. TSs are broadly grouped into two classes based on their sequence, quaternary structure, and enzyme regulation. We report the presence of a novel zinc ribbon domain in the N-terminal region preceding the catalytic core in TS. The zinc ribbon domain is present in TSs belonging to both classes. Our sequence analysis reveals that archaeal TSs possess all zinc chelating residues to bind a metal ion that are lacking in the structurally characterized homologs. Phylogenetic analysis suggests that TSs with an N-terminal zinc ribbon likely represents the ancestral state of the enzyme while TSs without a zinc ribbon must have diverged later in specific lineages. The zinc ribbon and its N- and C-terminal extensions are important for enzyme stability, activity and regulation. It is likely that the zinc ribbon domain is involved in higher order oligomerization or mediating interactions with other biomolecules leading to formation of larger metabolic complexes.     

The enzymatic basis for pesticide bioremediation

Enzymes are central to the biology of many pesticides, influencing their modes of action, environmental fates and mechanisms of target species resistance. Since the introduction of synthetic xenobiotic pesticides, enzymes responsible for pesticide turnover have evolved rapidly, in both the target organisms and incidentally exposed biota. Such enzymes are a source of significant biotechnological potential and form the basis of several bioremediation strategies intended to reduce the environmental impacts of pesticide residues. This review describes examples of enzymes possessing the major activities employed in the bioremediation of pesticide residues, and some of the strategies by which they are employed. In addition, several examples of specific achievements in enzyme engineering are considered, highlighting the growing trend in tailoring enzymatic activity to a specific biotechnologically relevant function.     

Metallocenter assembly in nickel-containing enzymes

 The five known nickel-dependent enzymes include urease, hydrogenase, carbon monoxide dehydrogenase (and CO dehydrogenase/acetyl-coenzyme A synthase), methyl-S–coenzyme M reductase, and one class of superoxide dismutase. Consistent with their disparate functions, these Ni enzymes have distinct metallocenter structures that vary in Ni coordination geometry, number and types of metals, and the presence of additional components. Sophisticated cellular Ni processing systems have been devised to allow for specific and functional incorporation of Ni into these proteins. This review highlights several themes that are common to the enzyme activation processes and summarizes current concepts related to the enzyme-specific Ni assembly pathways. Received, accepted: 3 April 1997     

Extracellular peptidases of insect-associated fungi and their possible use in biological control programs and as pathogenicity markers

This review deals with characteristics of peptidases of fungi whose life cycles are associated with insects to varying degrees. The review examines the characteristic features of the extracellular peptidases of entomopathogenic fungi, the dependence of the specificity of these peptidases on the ecological characteristics of the fungi, and the role of peptidases in the development of the pathogenesis. Data on the properties and physiological role of hydrolytic enzymes of symbiotic fungi in “fungal gardens” are also considered in detail. For the development of representations about mechanisms of control over populations of insect pests, special attention is given to analysis of possibilities of genetic engineering for the creation of entomopathogens with enhanced virulence. Clarification of the role of fungi and their secreted enzymes and careful environmental studies are still required to explain their significance in the composition of the biota and to ensure widespread adoption of these organisms as effective biological control agents. The systematization and comparative analysis of the existing data on extracellular peptidases of insect-associated fungi will help in the planning of further work and the search for markers of pathogenesis and symbiosis.     

Tissue-Characteristic Expression of Mouse Proteome

The mouse is a valuable model organism for biomedical research. Here, we established a comprehensive spectral library and the data-independent acquisition–based quantitative proteome maps for 41 mouse organs, including some rarely reported organs such as the cornea, retina, and nine paired organs. The mouse spectral library contained 178,304 peptides from 12,320 proteins, including 1678 proteins not reported in previous mouse spectral libraries. Our data suggested that organs from the nervous system and immune system expressed the most distinct proteome compared with other organs. We also found characteristic protein expression of immune-privileged organs, which may help understanding possible immune rejection after organ transplantation. Each tissue type expressed characteristic high-abundance proteins related to its physiological functions. We also uncovered some tissue-specific proteins which have not been reported previously. The testis expressed highest number of tissue-specific proteins. By comparison of nine paired organs including kidneys, testes, and adrenal glands, we found left organs exhibited higher levels of antioxidant enzymes. We also observed expression asymmetry for proteins related to the apoptotic process, tumor suppression, and organ functions between the left and right sides. This study provides a comprehensive spectral library and a quantitative proteome resource for mouse studies.     

Performance,gut morphology and carcass characteristics of fattening rabbits as affected by particle size of pelleted diets

A review of past literature revealed inconsistencies in recommended feed particle size for optimal growth and productive performance of rabbits. Changing diet formulation and subsequent processing conditions may improve pellet texture and potentially affect rabbit performance. In the current study, two isoenergetic and isonitrogenous pelleted diets were formulated, which varied in the particle size of the concentrates (2 and 8 mm, respectively). The objective was to evaluate the effect of different particle sizes of compound diets on performance, nutrient utilisation, gut morphology, and carcass characteristics of fattening Italian White breed rabbits. The finely ground diet led to a significant improvement in feed efficiency and apparent digestibility of crude protein, ether extract, crude fibre and NDF, without any negative effect on gut morphology. Furthermore, a smaller particle size of concentrates in pelleted diets improved carcass traits. Meat colour parameters showed significant differences in longissimus lumborum and biceps femoris due to dietary treatments, but in both muscles pH values 1 h and 24 h after slaughter remained unchanged. It is concluded that a finely ground pelleted diet can be used to improve growth performance of rabbits without affecting carcass parameters.