Ovarian follicular dynamics and hormones throughout the estrous cycle in Thai native (Bos indicus) heifers

Relatively few studies have been reported regarding the reproductive physiology of female Thai native cattle. Therefore, the objective of the present study was to evaluate the follicular dynamics and concentrations of follicle stimulating hormone (FSH), estradiol (E2) and progesterone (P4) during the estrous cycle in Thai native heifers (TNH) and to compare obtained results with those of European and Indian cattle breeds previously reported. For the detection of estrus, ovaries of all 20 heifers were examined twice daily (12 h intervals) by ultrasonography for three consecutive estrous cycles. From data of 60 estrous cycles (n = 60 estrous cycles from 20 heifers), it was found that 14 (70%) and 6 heifers (30%) had two (42 estrous cycles collected from 14 heifers) and three follicular waves (18 estrous cycles collected from 6 heifers), respectively. The days when estrus was detected, interovulatory intervals, life‐spans of corpus lutea (CL), and days for growing and regression of CLs were shorter in the two follicular waves than those in the three follicular waves (P < 0.05). In both two and thre follicular waves, larger maximum diameters and higher growth rates of the dominant follicle (DF) in an ovulatory wave were observed than those of the preceding waves without ovulation (P < 0.05). There was a progressive increase in follicular size and FSH and E2 production during follicular growth in each follicular wave. In addition, the FSH and E2 peak concentrations during the ovulatory wave were higher than those of the anovulation waves (P < 0.05). Moreover, although the ovarian follicular dynamic patterns in Thai native heifers were similar to those previously reported for European and Indian cattle breeds, the diameter of the largest preovulatory follicle (OF), subordinate follicles (SF) and CLs were smaller than those in European and Indian cattle breeds. In conclusion, when compared with European and some breeds of Indian cattle, the length of interovulatory intervals was shorter, and the sizes of dominant SF and CLs were smaller in Thai native heifers.     

Comparison of environmental conditions in two representative oyster farming areas: Hiroshima Bay,western Japan and Oginoham a Bay (a branch of Ishinomaki Bay), northern Japan

ABSTRACT:   Sea water environmental conditions over annual cycles were investigated and compared between two oyster farming areas, western Hiroshima Bay and Oginohama Bay (a branch of Ishinomaki Bay) in Miyagi Prefecture, to appropriately manage oyster culture or more efficiently utilize farming areas. The environmental parameters of temperature, salinity, nutrient concentrations (NO₂–N, NO₃–N, NH₄–N, PO₄–P, and SiO₂–Si) and size-fractionated chlorophyll- a (<0.2, 2–20, >20µm), and abundances of microzooplankton were measured in each bay at the surface, and 2 and 5 m depth layers. Differences in the annual mean values and results with monthly paired Student's t -tests showed that salinity was lower, and temperature, nutrient (especially PO₄–P) and chlorophyll- a concentrations, and abundance of microzooplankton, were higher in Hiroshima Bay than in Oginohama Bay. Differences in environmental conditions between inshore and offshore areas of each bay suggest that inflows of river water in western Hiroshima Bay and sea water from offshore had the most significant effects on the environmental conditions. It is concluded that such oceanographic and biological differences strongly affect the oyster farming system, especially regarding the optimum usage of offshore areas in Summer under clean, cold and stable seawater conditions, rather than food quantity in Hiroshima Bay, and under more abundant food conditions in Oginohama Bay.     

Fate and Transport of Nursery-Box-Applied Tricyclazole and Imidacloprid in Paddy Fields

The fate and transport of tricyclazole and imidacloprid in paddy plots after nursery-box application was monitored. Water and surface soil samples were collected over a period of 35 days. Rates of dissipation from paddy waters and soils were also measured. Dissipation of the two pesticides from paddy water can be described by first-order kinetics. In the soil, only the dissipation of imidacloprid fitted to the simple first-order kinetics, whereas tricyclazole concentrations fluctuated until the end of the monitoring period. Mean half-life (DT₅₀) values for tricyclazole were 11.8 and 305 days, respectively, in paddy water and surface soil. The corresponding values of imidacloprid were 2.0 and 12.5 days, respectively, in water and in surface soil. Less than 0.9% of tricyclazole and 0.1% of imidacloprid were lost through runoff during the monitoring period even under 6.3 cm of rainfall. The pesticide formulation seemed to affect the environmental fate of these pesticides when these results were compared to those of other studies.     

Changes in aboveground and belowground properties during secondary natural succession of a cool-temperate forest in Japan

Forest development in temperate regions is considered to be a global carbon sink. Many studies have examined forest development after harvesting or fire from aboveground (e.g., biomass) or belowground (e.g., soil nutrient) perspectives. However, few studies have explored forest development from both perspectives simultaneously in cool-temperate forests in Japan. In this study, we examined changes over 105 years in both aboveground and belowground components during secondary natural succession. The aboveground biomass increased for 50 years and reached a plateau in a 105-year-old stand. The N mineralization rate increased during succession for 50 years, but showed a decline in the 105-year-old stand due to the decrease in the nitrification rate in late succession. The percent nitrification (i.e., relative contribution of nitrification to N mineralization) decreased significantly with increasing forest stand age. The N mineralization rates had significant relationships with N concentrations of the dominant tree foliage and litter fall and with the amount of litter fall N. Meanwhile, other belowground properties (i.e., soil pH, phenol concentration, soil microbial respiration, and litter mass loss) did not show any significant relationship with forest stand age. This may be because the soil at the study sites was heterogeneous and consisted of Cambisols and Andosols, the latter of which originally has high organic matter content, and thus may have buffered the effect of the aboveground development. These results indicate that belowground N dynamics are more closely associated with aboveground development than other belowground properties in these forests.     

Insect glutathione S-transferase: Separation of transferases from fat bodies of American cockroaches active on organophosphorus triesters

Several glutathione S-transferases which catalyze the conjugation of reduced glutathione with organophosphorus triesters were separated from fat bodies of adult female American cockroaches, Periplaneta americana (L.). Two transferases (I, V) were active on diazinon and three transferases (II, III, IV) were active on methyl parathion. The transferase (I) active on the pyrimidinyl moiety of diazinon was distinguishable from the other transferases on the O-methyl portion of methyl parathion, as shown by chromatographic properties, and additionally it was almost inactive or less active on 3,4-dichloronitrobenzene, methyl iodide, p-nitrobenzyl chloride, trans-cinnamaldehyde, and 1,2-epoxy-3-(p-nitrophenoxy)propane. Transferase II had high activities with “aryl” and “aralkyl” compounds, transferase III with “epoxide” and “alkene,” and transferase IV with “alkyl,” “aryl,” and “aralkyl” compounds. This indicated that the transferases had overlapping substrate specificities. The molecular weight was 35,000–37,000 for both of the enzymes active on methyl parathion and diazinon. The pH optima with methyl parathion and diazinon were about 8.5 and 6.5, respectively. At a glutathione concentration of 5 mM, Michaelis constants were 0.28 and 0.13 mM for methyl parathion and diazinon, respectively.     

Effect of lactoferrin on murine embryo development created from lipopolysaccharide-treated sperm

The effect of lactoferrin (LF) on embryo development was investigated by using lipopolysaccharide (LPS)-treated mouse sperm. For the development rate of the 2-cell stage embryo, the embryo derived from LPS- and LF-treated sperm showed similar survival rate to the control embryo. On day 12 after the embryo transfer into the recipient, the frequent abnormality was observed in the embryo derived from LPS-treated sperm, and the abnormality was tended to be inhibited in the embryo derived from LPS- and LF-treated sperm. These results imply that LF treatment on sperm contaminated with bacteria may facilitate the embryo development, which contribute to the improvement of infertility.     

Nitrogen balance in a paddy field planted with whole crop rice (Oryza sativa cv. Kusahonami) during two rice-growing seasons

This paper focuses on N balance in a paddy field planted with whole crop rice (Oryza sativa cv. Kusahonami). The experiment was conducted with two treatments during two rice-growing seasons: one was fertilized with N (160 kg N ha^–1; 16N plot) and the other unfertilized (0N plot); both plots were fertilized with P and K. The N input from precipitation was 15 and 12 kg N ha^–1 in 2002 and 2003, respectively. The N input from irrigation water reached as much as 123 and 69 kg N ha^–1 in 2002 and 2003, respectively. This was because irrigation water contained higher NO₃^– concentrations ranging from 4 to 8 mg N l^–1. The N uptake by rice plants was the major output: 118 and 240 kg N ha^–1 in the 0N and 16N plots in 2002 and 103 and 238 kg N ha^–1 in 2003, respectively. N losses by leaching were 4.8–5.3 and 6.5–7.3 kg N ha^–1 in 2002 and in 2003, respectively. Laboratory experiments were carried out to estimate the amounts of N₂ fixation and denitrification. Amount of N₂ fixation was 43 and 0 kg N ha^–1 in the 0N and 16N plots, respectively. Denitrification potential was quite high in both the plots, and 90% of the N input through irrigation water was lost through denitrification. Collectively, the total N inputs were relatively large due to irrigation water contaminated with NO₃^–, but N outflow loading, expressed as leaching–(irrigation water + precipitation + fertilizer), showed large negative values, suggesting that the whole crop rice field might serve as a constructed wetland for decreasing N.     

Effects on flowering and seed yield of dominant alleles at maturity loci E2 and E3 in a Japanese cultivar,Enrei

‘Enrei’ is the second leading variety of soybean (Glycine max (L.) Merr.) in Japan. Its cultivation area is mainly restricted to the Hokuriku region. In order to expand the adaptability of ‘Enrei’, we developed two near-isogenic lines (NILs) of ‘Enrei’ for the dominant alleles controlling late flowering at the maturity loci, E2 and E3, by backcrossing with marker-assisted selection. The resultant NILs and the original variety were evaluated for flowering, maturity, seed productivity and other agronomic traits in five different locations. Expectedly, NILs with E2 or E3 alleles flowered later than the original variety in most locations. These NILs produced comparatively larger plants in all locations. Seed yields were improved by E2 and E3 in the southern location or in late-sowing conditions, whereas the NIL for E2 exhibited almost the same or lower productivity in the northern locations due to higher degrees of lodging. Seed quality-related traits, such as 100-seed weight and protein content, were not significantly different between the original variety and its NILs. These results suggest that the modification of genotypes at maturity loci provides new varieties that are adaptive to environments of different latitudes while retaining almost the same seed quality as that of the original.