Development of large and small blastomeres from 2‐cell embryos produced in vitro in pigs

In the present study, we examined the development to blastocysts of large and small blastomeres from unevenly cleaved 2‐cell embryos (uneven 2‐cell embryos) in pigs. Proportion of blastocysts derived from large blastomeres (52.8 ± 6.4%) was significantly higher (P < 0.05) compared with small ones (32.1 ± 4.6%). However, there were no differences in total cell number, inner cell mass (ICM) cell number and ICM/total cells ratio between them. Of 53 sister blastomere pairs in the same embryos examined there were 12 pairs (22.6%) in which both blastomeres developed to blastocysts, 16 pairs (30.2%) in which only large blastomeres developed to blastocysts, and five pairs (9.4%) in which only small blastomeres developed to blastocysts. Relative total amount of active mitochondria in small blastomeres were lower (P < 0.05) than that of large blastomeres and blastomeres from evenly cleaved 2‐cell embryos. However, there was no difference in relative density of active mitochondria in these three types of blastomeres. In conclusion, blastocysts derived from small and large blastomeres in uneven 2‐cell embryos had comparable quality in terms of cell number, ICM number, ICM/total cell ratio and distribution of active mitochondria. The results suggest that these blastomeres may contribute multiple offspring production in pigs.     

Growth of uniformly oriented silica MFI and BEA zeolite films on substrates

Applications of zeolite films benefit from alignment of the integrated channels, but methods for film growth have nearly always introduced orientational randomization in the direction normal to the substrate. We now report facile methods to grow silicalite-1 films and pure silica beta zeolite films on substrates with straight or sinusoidal channels positioned uniformly upright at a thickness of up to 8 micrometers. Precise gel compositions and processing temperatures are critical to promote secondary growth on pre-formed oriented crystal monolayers while suppressing self-crystallization in the bulk medium. Preliminary results highlight the potential of these uniformly oriented films in the nonlinear optical response and separation of xylene isomers.     

Comparison of paddy soil fertility under conventional rice straw application versus cow dung compost application in mixed crop–livestock systems in a cold temperate region of Japan

ABSTRACT

After the rice harvest in Japan, rice straw (RS) is usually cut by combine harvester and incorporated into the soil to improve its fertility. In mixed crop–livestock systems, however, RS is collected and used as livestock feed, and cow dung compost (CDC) is then applied to the soil. This system utilizes the residual organic matter from both rice production and livestock husbandry to make each product. CDC application is also considered to improve the fertility of paddy soil. However, the nutrient input from CDC and the effect of CDC application on soil fertility vary among regions and/or soil types. We compared soil fertility between RS application (RS treatment, avg. 32 years) and RS removal plus CDC application (CDC treatment, avg. 21 years) in 79 paddy fields in Mamurogawa town, Yamagata Prefecture, a cold temperate region of Japan, and measured the nutrient contents in the applied RS and CDC. The total C content of RS was significantly higher than that of CDC, whereas the N, P, K, and Si contents of CDC were significantly higher than those of RS. However, there was no significant difference in paddy soil fertility – as measured by soil organic C, total N, CEC, available N, P, and Si, exchangeable K, Ca, and Mg, base saturation percentage, pH, and bulk density – between the treatments. The soil fertility of most fields was adequate by RS or CDC treatment. Thus, leaving RS in paddy fields or removing it and then adding CDC to the paddy fields has a similar effect in maintaining adequate soil fertility for single rice production or rice–livestock production systems.     

Effect of wounding on cell wall hydrolase activity in tomato fruit

Changes in the activity of the cell wall hydrolases – polygalacturonase (EC 3.2.1.15), pectinesterase (EC 3.2.1.11) and β-galactosidase (EC 3.2.1.23) – have been investigated following wounding of tomato fruit pericarp tissue (Lycopersicon esculentum cv. Ailsa Craig). In ripening fruit wounding appears to arrest the further synthesis of polygalacturonase. β-Galactosidase synthesis may also have been arrested in ripening fruit. The level of pectinesterase declined over the first 24 h following harvest, and since this was apparent in both wounded and unwounded tissue may be related to a harvest, rather than a wounding effect. There was a recovery of activity in intact fruit by 48 h after harvest but this seems to be impaired in wounded tissue. In the case of pectinesterase, this observation was extended to examine the changes in isoform profile and it appeared that the decline of this enzyme may be associated with the reduction of one specific isoform — PE2. In contrast to ripening fruit, wounding of fruit at the fully ripe stage appears to have no significant effects on the activities of any of these three enzymes.     

Culture-based fisheries in small reservoirs in northern Vietnam: effect of stocking density and species combinations

This study was conducted in 20 reservoirs, ranging in size from 4 to 30 ha, in the mountainous, northern region of Vietnam, in ThaiNguyen and YenBai provinces, over two growth cycles in 2002/03 and 2003/04. The reservoirs are leased by farmers for fishery activities from the provincial administration, and the trials were managed by the lessee farmers. Three species combinations in ratios (by fingerling weight) of grass carp: silver carp: bighead carp: common carp: mrigal 1:2:1:1:3 (A), 1:3:1:1:2 (B) and 1:2:1:1:2 (C) were used as seed stock. The overall mean yield of stocked fish in 2002/03 and 2003/04 growth cycles in reservoirs in ThaiNguyen and YenBai provinces was 165 (±21) and 190 (39), and 287 (±22) and 325 (±24) kg ha^?1 respectively. The yield in reservoirs in both provinces, in both growth cycles and irrespective of the species combinations, increased in relation to stocking density. In reservoirs in ThaiNguyen Province, the species combination B gave the lowest yield (both growth cycles and overall), and differed significantly (P<0.05) from combinations A and C. The stocking efficiency (ratio of the yield of stocked fish in kg ha^?1 to the weight of the stocked fish in kg ha^?1) in reservoirs in ThaiNguyen Province ranged from 2.9 to 5.1 over the two growth cycles and that in YenBai from 2.8 to 3.9. There was no discernible trend between growth cycles and/or between species combinations. The major cost incurred was for fingerling procurement. In all instances, a net profit was accrued. The mean (±standard error (SE)) net profit ha^?1 (in 10³VN dong; approximately 15 500 VND=1 US$) was 885 (±270) and 864 (±214), and 1322 (±176) and 1600 (±150) for the growth cycles 2002/03 and 2003/04 for reservoirs in ThaiNguyen and YenBai provinces respectively. Between the two growth cycles, the net profit increased in eight and three reservoirs from YenBai and ThaiNguyen, respectively, the maximum increase being recorded in Khuan Gio (165%) and Dong Man (39%) reservoirs.     

Characterization of a heterodimeric GH2 β-galactosidase from Lactobacillus sakei Lb790 and formation of prebiotic galacto-oligosaccharides

The lacLM genes from Lactobacillus sakei Lb790, encoding a heterodimeric β-galactosidase that belongs to glycoside hydrolase family GH2, were cloned and heterologously expressed in Escherichia coli . Subsequently, the recombinant β-galactosidase LacLM was purified to apparent homogeneity and characterized. The enzyme is a β-galactosidase with narrow substrate specificity because o-nitrophenyl-β-D-galactopyranoside (oNPG) was efficiently hydrolyzed, whereas various structurally related oNP analogues were not. The K(m) and k(cat) values for oNPG and lactose were 0.6 mM and 180 s(-1) and 20 mM and 43 s(-1), respectively. The enzyme is inhibited competitively by its two end-products D-galactose and D-glucose (K(i) values of 180 and 475 mM, respectively). As judged by the ratio of the inhibition constant to the Michaelis constant, K(i)/K(m), this inhibition is only very moderate and much less pronounced than for other microbial β-galactosidases. β-Galactosidase from L. sakei possesses high transgalactosylation activity and was used for the synthesis of galacto-oligosaccharides (GalOS), employing lactose at a concentration of 215 g/L. The maximum GalOS yield was 41% (w/w) of total sugars at 77% lactose conversion and contained mainly non-lactose disaccharides, trisaccharides, and tetrasaccharides with approximately 38, 57, and 5% of total GalOS formed, respectively. The enzyme showed a strong preference for the formation of β-(1→6)-linked transgalactosylation products, whereas β-(1→3)-linked compounds were formed to a lesser extent and β-(1→4)-linked reaction products could not be detected.     

Improvement of porcine oocytes with low developmental ability after fusion of cytoplasmic fragments prepared by serial centrifugation

We have shown in pigs that oocytes denuded of cumulus cells at 24 h of in vitro maturation culture and subsequently matured for a total of 46 h (DO24 oocytes) have lower cytoplasmic maturity than those matured with cumulus cells for 46 h and then denuded (DO46 oocytes). In the present study, DO24 zona-free oocytes were fused with one (1C) or two (2C) cytoplasmic fragments produced by serial centrifugation ("centri-fusion") of DO46 oocytes (DO24+1C and DO24+2C oocytes, respectively). Groups of (1) DO46 (a control), (2) DO24, (3) DO24+1C and (4) DO24+2C oocytes were partheno-activated by an electrical pulse or fertilized in vitro and subsequently cultured for 6 days. In the fused groups, female pronucleus (FPN) formation rates were higher than that in the DO24 group after parthenogenetic activation (PA); however, the blastocyst rates were intermediate between those of the control and DO24 groups. After in vitro fertilization, the male pronucleus (MPN) formation rates in the fused groups were similar to that in the control group and higher than that in the DO24 group; the normal fertilization rate in the DO24+2C group was higher than that in the DO24 group and similar to that in the control group, resulting in significantly higher blastocyst rates in the DO24+2C and control groups than that in the DO24 group. These results suggest that centri-fusion using ooplasm from fully matured DO46 oocytes can offer a potentially novel approach for restoration of cytoplasmic maturity to oocytes with low developmental ability and subsequent improvement of fertilization and developmental competence.     

Landscape-scale geographic variations in microbial biomass and enzyme-labile phosphorus in manure-amended Hapludults

Long-term nutrient management practices have lasting effects on the geographic distribution of soil microorganisms, loci of enhanced activity, and non-mobile nutrients such as phosphorus (P) to ultimately influence nutrient use efficiency by crops and edge-of-field losses. We determined the distribution of soil microbial biomass, phosphomonoesterases' activity, and P forms in a 10-ha no-till field that received annual additions of dairy manure at 0, 15, and 30 kg P ha^?1 at the field scale for 16 consecutive years. The spatial structure of soil microbial indices and extractable P fractions were characterized based on their semivariance distributions for each manure treatment. The buildup in soil P occurred, although replacement was done at a crop removal rate. Manure additions resulted in overall mean increases in total labile P of 73 % and 156 % and alterations in the soil microbial ecosystem that depended on manure inorganic-to-enzyme-labile P composition in soils treated with 15 and 30 kg P ha^?1, respectively. Distinct clusters of phosphate- and enzyme-labile organic P were observed within manure treatments, where accumulation of the latter forms was associated with high soil microbial biomass C and reduced acid phosphomonoesterase activity. The geographic variability highlighted the critical need for improving methods of field-scale application of manure and non-mobile nutrients. In addition, current soil testing methods that depend upon composite representative samples for estimating microbiological parameters linked to nutrient turnover and P requirements for optimal crop production should be modified to include site-specificity in sampling and interpretation approaches.     

Phosphorus sorption in soils of the Mekong Delta (Vietnam) as described by the binary Langmuir equation

Phosphate adsorption isotherms were determined for 20, mostly very acidic, soils from the Mekong Delta. The experimental data were well described by a binary Langmuir equation which considers two groups of sorption sites that differ in their P bonding energies. The maximum P-sorption capacities of these sites were related to the soil properties by simple linear correlation and by stepwise multiple regression. Results suggest that high energy sites are on Al-oxihydroxides or small Al-substituted Fe-oxides and, to a lesser extent, on poorly ordered Fe-oxihydroxides. On the other hand, the P-sorption capacity of low energy sites is mainly related to clay content, and it increases as pH decreases. These sites are also positively correlated with organic carbon and poorly crystalline Fe-oxihydroxides. However, as these two variables are closely correlated with each other, organic matter is likely to be considered as an indirect factor of P fixation through its association with Fe-oxihydroxides and not as an important source of P-sorption sites. The maximum sorption capacity, i.e. the sum of sorption capacities of the two groups of sites, is well described (r²= 0.88) by an equation that takes into account the four variables identified above: Al-bearing oxihydroxides, poorly ordered Fe-oxihydroxides, clay content and pH. Grouping the soils according to the orders of Soil Taxonomy, the P-sorption capacity increases in the following sequence: ultisols < entisols < inceptisols. A P concentration often considered adequate for plant nutrition is 0.2 mg P 1^?1 solution, and only the high energy sites are involved in sorption at that concentration. Thus an equation including only Al- and Fe-oxihydroxides could be used to fix P norms in these soils.