A sperm cytoskeletal protein that signals oocyte meiotic maturation and ovulation

Caenorhabditis elegans oocytes, like those of most animals, arrest during meiotic prophase. Sperm promote the resumption of meiosis (maturation) and contraction of smooth muscle-like gonadal sheath cells, which are required for ovulation. We show that the major sperm cytoskeletal protein (MSP) is a bipartite signal for oocyte maturation and sheath contraction. MSP also functions in sperm locomotion, playing a role analogous to actin. Thus, during evolution, MSP has acquired extracellular signaling and intracellular cytoskeletal functions for reproduction. Proteins with MSP-like domains are found in plants, fungi, and other animals, suggesting that related signaling functions may exist in other phyla.     

Synthesis of a stable compound with fivefold bonding between two chromium(I) centers

Although in principle transition metals can form bonds with six shared electron pairs, only quadruply bonded compounds can be isolated as stable species at room temperature. Here we show that the reduction of {Cr(mu-Cl)Ar'}2 [where Ar' indicates C6H3-2,6(C6H3-2,6-Pri2)2 and Pr indicates isopropyl] with a slight excess of potassium graphite has produced a stable compound with fivefold chromium-chromium (Cr-Cr) bonding. The very air- and moisture-sensitive dark red crystals of Ar'CrCrAr' were isolated with greater than 40% yield. X-ray diffraction revealed a Cr-Cr bond length of 1.8351(4) angstroms (where the number in parentheses indicates the standard deviation) and a planar transbent core geometry. These data, the structure's temperature-independent paramagnetism, and computational studies support the sharing of five electron pairs in five bonding molecular orbitals between two 3d5 chromium(I) ions.     

Gene for von Recklinghausen neurofibromatosis is in the pericentromeric region of chromosome 17

Linkage analysis of 15 Utah kindreds demonstrated that a gene responsible for von Recklinghausen neurofibromatosis (NF) is located near the centromere on chromosome 17. The families also gave no evidence for heterogeneity, indicating that a significant proportion of NF cases are due to mutations at a single locus. Further genetic analysis can now refine this localization and may lead to the eventual identification and cloning of the defective gene responsible for this disorder.     

True potato seed research and development in Vietnam

Quality tuber planting material is unavailable in the Red River Delta (RRD). The use of True Potato Seed (TPS) was considered as an alternative planting material. During the 1985–86 and 1986–87 seasons, 21 and 40 kilos of open pollinated TPS, respectively, were collected in the southern highlands and distributed to over 40 cooperative groups of farmers in the RRD. Fifty-two hectares (1985-86) and 120 hectares (1986-87) of potatoes were produced from transplants in the two years of on-farm production. Approximately 50% of the farmers were successful in both years. Lack of experience and too wet or too dry growing conditions caused most of the failures. Yields from transplants ranged from 5 to 13 t/ha with 150 to 300 seedling tubers/m². Seedling tubers can be stored for eight months with low storage losses and when replanted give substantially higher yields than those obtained from locally grown, degenerated seed tubers.     

Colonic permeability is higher in Great Danes compared with smaller breed-dogs

Fed the same dry diet, large dogs show poorer fecal quality than small ones. A high colonic permeability could explain a low water and electrolyte net balance leading to high fecal water content. This experiment was conducted to evaluate colonic permeability in dogs varying in body size and to determine whether colonic permeability is related to fecal sodium concentration and fecal quality. Four breeds of dogs were used: six Miniature Poodles (MP), six Standard Schnauzers (SS), six Giant Schnauzers (GS) and six Great Danes (GD). Colonic permeability was evaluated using the ratio of urinary lactulose to sucralose (L:S) after oral administration. Fecal sodium concentration was measured by flame photometry. The urinary L:S ratio was significantly lower in GD, indicating a higher colonic permeability, than in the three other breeds (0.35 ± 0.12 for GD and 0.51 ± 0.05 for MP). GD also presented the higher fecal sodium concentrations and the poorest fecal quality. The higher fecal sodium concentration observed in GD could be explained by the higher colonic permeability and both these variables could be important explanations for higher fecal moisture in large dogs.     

Rice albumin N-terminal (Asp-His-His-Gln) prevents against copper ion-catalyzed oxidations

Chromatographic separation of soluble proteins from rice (Oryza sativa L.) yielded a major albumin protein (16 kDa), with the DHHQVYSPGEQ sequence in the N terminus, showing antioxidant action. The rice albumin was more potent than other rice proteins in preventing Cu2+-induced low-density lipoprotein (LDL) oxidation. Additionally, it also exhibited a remarkable suppression of HOCl oxidation. In a further study, albumin inhibited Cu2+-induced oxidation of LDL in a stoichiometric manner with an EC50 value of 4.3 microM, close to that of serum albumins. Moreover, after digestion with trypsin or chymotrypsin, it maintained its antioxidant action. In an experiment to see the involvement of the N terminus in antioxidant action, a synthetic tetrapeptide, equivalent to the N terminus DHHQ, was found to inhibit Cu2+-induced LDL oxidation or degradation of apolipoprotein B, similar to that of rice albumin. In mechanistic analyses, the action of rice albumin or tetrapeptide is primarily due to the removal of Cu2+, as suggested from its inhibitory effect on Cu2+/diphenylcarbohydrazide (DPCH) complex formation. However, despite its similar inhibitory effect on Cu2+-induced oxidation of LDL, rice albumin was less effective than serum albumin in inhibiting Cu2+/DPCH complex formation, suggesting that the number of Cu2+-binding sites in rice albumin may be less than that in serum albumins. Taken together, rice albumin exerts a potent preventive action against Cu2+-induced oxidations, which is due to the Cu2+ binding by DHHQ in the N-terminal sequence. Such a role as a Cu2+ chelator would add up to the application of rice albumin protein.     

Genetic improvement of farmed tilapias: Composition and genetic parameters of a synthetic base population of Oreochromis niloticus for selective breeding

The present study is based on data recorded from fish of the third generation of the GIFT project (Genetic Improvement of Farmed Tilapias). The objective of the study was to compose a synthetic base population of Nile tilapia for further selective breeding, and to estimate phenotypic and genetic parameters in that population. The base population was formed by choosing parent stock among the best performing animals within the best strain combinations resulting from a full diallel cross design (8 × 8) involving four African wild strains and four Asian farmed strains (64 strain combination cells altogether). The grandparent ancestors of the base population were mainly representing the three strains originating from Egypt, Kenya and Thailand (20.2, 27.3 and 19.6%, respectively). The proportion of ancestors from the Senegal strain was medium (12.2%) whereas the proportion of ancestors from Ghana, Israel, Singapore and Taiwan strains was low (3 to 8%) and mainly due to a restriction that all parent strains should be represented in the synthetic base. Statistical analyses using a mixed animal model were carried out on records from 13,570 individually tagged and surviving progeny of 50 sires and 123 dams. The growth performance of the fish was tested in seven diverse environments. The test environments covered a wide range of tilapia farming systems, namely, earthen ponds fertilized with inorganic fertilizer and organic manure or on-farm agricultural residues, cage culture, and test stations located in different agro-climatic regions. The model fitted included the fixed effect of test environment and sex and the linear and quadratic covariate of age at stocking. The random terms were the additive genetic effect of individual fish and the additional effects common to full-sib groups. The estimates of heritability for body weight at harvest in different test environments ranged from moderate to high (0.12 to 0.56) and the estimate across test environments was 0.15. The variances due to other effects common to full-sib families were significant, accounting for 8 to 16% of total variation in body weight. The genetic correlations among body weights recorded in similar environments were high (mostly > 0.80, i.e. among the earthen ponds in experimental locations). By contrast, the genetic correlations between harvest weight in earthen pond and in cage environments were more variable (0.36-0.82). Overall, the results suggested that the genotype by environment interactions were of limited importance, at least for the target pond farming systems in the Philippines. It was concluded that as the additive genetic variation in the base population was large, the harvest weight of the GIFT fish could be effectively improved by selective breeding, and that there was no immediate need to develop separate strains for different environments.     

Screening of quinalphos,trifluralin and dichlorvos residues in fresh water of aquaculture systems in Mekong Delta,Vietnam

To develop an easy and reliable method for detecting pesticides and their residues in the Mekong Delta, a GC‐MS analytical method was developed and validated according to European guidelines (SANTE/11945/2015) for the determination of residues of three pesticides (quinalphos, trifluralin and dichlorvos) in water. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.002 and 0.007 μg/L, respectively, for quinalphos and trifluralin, and 0.016 and 0.053 μg/L, respectively, for dichlorvos and quinalphos. The repeatability, the within‐laboratory reproducibility as well as the trueness met the European criteria. The recovery rate ranged between 72% (for dichlorvos and quinalphos) and 82% (for trifluralin). The developed method was then applied for the analysis of 33 water samples, collected in April 2013, at the beginning of the rainy season in the Mekong Delta in Vietnam. Thirteen samples were from rice field, 10 were collected from cat fish ponds and from red tilapia cages. Results showed that only 9% of total water samples analysed contained residues of pesticides, but only in water from rice fish systems. From the 13 samples taken in these systems, quinalphos was detected in three samples. The other two pesticides were not detected. A comparison between analytical results obtained from GC‐MS and an alternative method, that is GC‐ECD indicated that GC‐ECD is less sensitive than GC‐MS, with LOQ ranging from 0.37 to 1.18 (depending on the pesticide). However, for samples with concentrations above these LOQ, no significant difference was observed between the results obtained from the two analytical methodologies.     

EFFICIENCY ANALYSIS AND THE EFFECT OF POLLUTION ON SHRIMP FARMS IN THE MEKONG RIVER DELTA

This article investigates the efficiency of intensive, semi-intensive, and extensive shrimp farming practices as well as the difference between the upstream and downstream efficiency of shrimp farms in the Mekong River Delta (MRD), Vietnam. Our article is the first to compare the efficiency of the 3 shrimp practices and investigate the difference between the efficiency of downstream and upstream farms. The efficiency of shrimp farms is measured using group-frontier and meta-frontier analysis on a sample of 292 farms. The results show that, on average, shrimp farms are inefficient; extensive farms are more efficient than intensive and semi-intensive farms; and, controlling for key socio-economic factors, upstream farms are more efficient than downstream farms, suggesting that pollution from upstream farms may influence shrimp farm efficiency. The results give some direction for improvement and some evidence to shrimp farmers and policymakers in the MRD to take the pollution problem seriously and find solutions for more sustainable development.