Rat liver lowM r phosphotyrosine protein phosphatase isoenzymes: Purification and amino acid sequences

Two lowM _r phosphotyrosine protein phosphatases have been isolated from rat liver. The enzymes were previously known as lowM _r acid phosphatases, but several recent studies have demonstrated that this family of enzymes possesses specific phosphotyrosine protein phosphatase activity. We determined the complete amino acid sequences of the two isoenzymes and named them AcP1 and AcP2. Both consist of 157 amino acid residues, are acetylated at the NH₂-terminus, and have His as the COOH-terminus. The molecular weights calculated from the sequences are 18,062 for AcP1 and 17,848 for AcP2. They are homologous except in the 40–73 zone, where about 50% of residues are different. This fact suggests that the two isoenzymes are produced by an alternative splicing mechanism. There is no homology between these two isoenzymes and the receptor-like phosphotyrosine protein phosphatases LAR, CD45, human placenta PTPase 1B, and rat brain PTPase-1. AcP1 and AcP2 are also distinct from rat liver PTPase-1 and PTPase-2, since these last enzymes have higher molecular weights. AcP1 differs from AcP2 with respect to (1) substrate affinity and (2) its sensitivity to activators and inhibitors, thus suggesting a their different physiological function.     

Conventional and Land-Time Budget Analysis of Rural Villages in Hubei Province,China

Five rural villages in Qianjiang County (Hubei province), PR China, were investigated to collect information on the socioeconomic characteristics relevant to farming system analysis. In each village, 50 households were randomly sampled and household heads interviewed. We first present the results of this conventional survey, which describes these five villages in terms of conventional socioeconomic parameters such as demographic variables, land availability and profiles of land use, time allocation and profiles of working time use, cash flows, and degree of food self-sufficiency. Then we change focus by characterizing household types rather than village types. This is done analyzing the same raw data aggregated at the household level to illustrate the difference of a parallel readings at different hierarchical levels. Finally, we present a new approach to organize the information gathered in the conventional way into “typologies” referring to both household and village level. Such a passage makes possible a multidimensional reading of the system. One key concept of this analysis is the land-time budget (LTB) approach, which is first explained in theoretical terms and then illustrated with examples applied to our data set.     

Synthesis and structure–activity relationships of fibrate-based analogues inside PPARs

In an effort to develop safe and efficacious compounds for the treatment of metabolic disorders, new compounds based on a combination of clofibric acid, the active metabolite of clofibrate, and lipophilic groups derived from natural products chalcone and stilbene were synthesised. Some of them were found to be active at micromolar concentrations only on PPARα or PPARγ, while others were identified as dual agonists PPARα/γ.     

Duck skeletal muscle acylphosphatase: Primary structure

The complete amino acid sequence of duck skeletal muscle acylphosphatase is presented. The sequence was studied by the manual Edman degradation of the complete series of tryptic peptides and the amino acid composition of peptic peptides. The NH₂-terminus is acetylated, and the polypeptide consists of 102 amino acid residues. The sequence is compared with other known acylphosphatases from the skeletal muscle of several vertebrate species.     

Signatures of de‐domestication in autochthonous pig breeds and of domestication in wild boar populations from MC1R and NR6A1 allele distribution

Autochthonous pig breeds are usually reared in extensive or semi‐extensive production systems that might facilitate contact with wild boars and, thus, reciprocal genetic exchanges. In this study, we analysed variants in the melanocortin 1 receptor (MC1R) gene (which cause different coat colour phenotypes) and in the nuclear receptor subfamily 6 group A member 1 (NR6A1) gene (associated with increased vertebral number) in 712 pigs of 12 local pig breeds raised in Italy (Apulo‐Calabrese, Casertana, Cinta Senese, Mora Romagnola, Nero Siciliano and Sarda) and south‐eastern European countries (Kr?kopolje from Slovenia, Black Slavonian and Turopolje from Croatia, Mangalitsa and Moravka from Serbia and East Balkan Swine from Bulgaria) and compared the data with the genetic variability at these loci investigated in 229 wild boars from populations spread in the same macro‐geographic areas. None of the autochthonous pig breeds or wild boar populations were fixed for one allele at both loci. Domestic and wild‐type alleles at these two genes were present in both domestic and wild populations. Findings of the distribution of MC1R alleles might be useful for tracing back the complex genetic history of autochthonous breeds. Altogether, these results indirectly demonstrate that bidirectional introgression of wild and domestic alleles is derived and affected by the human and naturally driven evolutionary forces that are shaping the Sus scrofa genome: autochthonous breeds are experiencing a sort of ‘de‐domestication’ process, and wild resources are challenged by a ‘domestication’ drift. Both need to be further investigated and managed.     

Environmental and Socioeconomic Constraints to the Development of Freshwater Fish Aquaculture in China

In this article, we provide an overview, on freshwater fish aquaculture in P.R. China, with special emphasis on pond fish culture. We describe the history, ecology (trophic structure and species reared), and technological aspects (including inputs/outputs, yields, labor productivity, and fossil energy use) of freshwater fish production and analyze its role in relation to the socioeconomic context. We discuss the prospects for intensification of production. In China, freshwater fish aquaculture has always been closely linked to cultivation of crops and animal husbandry, that is, feed inputs are in the form of agricultural wastes. The close integration with the farming system at large results in an efficient use of nutrients, low environmental loading, and little dependence on fossil energy inputs. About 7 to 9 different fish species, mainly herbivores, are kept in the same pond and efforts are made to maintain as much as possible the natural mechanisms of matter regulation and energy flows within the pond ecosystem. However, ecological compatibility is paid for by relatively low productivity, both per hectare of waterbody and per hour of labor input. If the throughput of freshwater fish production per unit of area and labor are to be dramatically increased, the equilibrium of the traditional integrated system will be difficult to maintain.