• Tribology and Lubricants
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• v.32 no.6
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• pp.195-200
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• 2016

This study examines the wear behavior of mild steel pins mated against alloyed tool steel discs in a pin-on-disc type sliding test machine and provides specific clarification regarding the effects of disc hardness on the wear behavior of a mating mild steel pin. The analysis confirms these effects through the observation of differences in the wear rates of the mild steel pins at low sliding speed ranges. These differences occur even though the hardness of the mating disc does not affect the wear characteristic curve patterns for the sliding speeds, regardless of the wear regime. In the running-in wear regime, increasing the hardness of the mating disc results in a decrease in the wear rates of the mild steel pins at low sliding speed ranges. However, in the steady-state wear region, the wear rate of a pin mated against the 42DISC is greater than the wear rate of a pin mated against the 30DISC, which has a lower hardness value. This means that the tribochemical reactivity of the mating disc, which is based on hardness value, influences the wear behavior of mild steel at low sliding speed ranges. In particular, oxides with higher oxygen contents, such as $Fe_2O_3$ oxides, form predominantly on the worn surface of the 42DISC. On the contrary, the wear behavior of mild steel pins at high sliding speed ranges is nearly unaffected by the hardness of the mating disc.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.73-79
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• 2002

To investigate the usability of frozen canine embryos for embryo transfer in the dog, 19 donors, 3 recipients, and 6 male dogs were used for the experiment. Natural mating or artificial insemination was performed for breeding the bitches in natural estrus. Vaginal smear test along with progesterone titre test were performed to detect the appropriate mating time and the bitches were bred twice during 3-6days following LH surge. Embryo collection was done on 8, 9-11, 12-13 days after the second mating to collect morula and blastocyst. Embryos were frozen using a programmable freezer and preseued in LNE tank. Embryos were thawed in 37$^{\circ}C$ water for 15 seconds and transferred into each uterine horn within 30 minutes. Embryos were collected from 13 bitches of 19 donors(68.4%) and the collected embryos were from between 9 and 13 days after 2nd mating. Embryos were produced both by natural mating(60.0%, 9115) and AI with frozen semen(100.0%, 4/4). Embryos were collected from the donors weighed between 2.5 and 30 kg and their age was from 1.5 to 3 years. 52 embryos were collected from 13 donors and the mean number of embryos was four. The stage of embryos was from 2-cell to gastrula and morulae were colledted mostly from 10 to 11 days after 2nd mating. Embryos were collected evenly from each uterine horn and the rate of embryo collection for the number of corpus luteum was 83.9%. Embryos were transferred to 3 recipients(morula 8, blastocyst 1, gastrula 8), however, no offspring was produced.

• The Korean Journal of Mycology
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• v.30 no.2
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• pp.152-156
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• 2002

Distribution and alteration of mating type of Korean population for Phytophthora capsici were monitored from 1995 to 1998. Total 973 isolates collected from 75 pepper fields throughout the country were divided into A1 mating type 573 isolates and A2 mating type 400 isolates. Both mating types were founded in all provinces examined, but the distribution patterns differed between the fields, The single mating type of A1 or A2 isolates was found in some fields, whereas various combinations of both mating types were in all years and provinces surveyed. Ratios of A1 and A2 were varied with years and fields. However, only single mating type either A1 or A2 was detected in some fields. While, in another field located in Gongju, only A2 isolates were detected in 1995 and 1997, but A1 isolates were appeared in 1998. Varied ratios and alterations of A1 and A2 mating type in fields indicate a potential sexual recombination of the fungus, which may cause genetic diversity.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.47-54
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• 2018

This study examined the behavior of red fox (Vulpes vulpes) during the estrus period, breeding period, and mating including the estrus period along as well as the effect of environmental factors in an outdoor breeding facility. The average mating duration was 19.95 min (n = 13, range = 1.17-35.25 min). The breeding season was mainly early February (56.6%) for foxes aged more than one year and mid-March (60.0%) for foxes aged less than one year. The mating duration was longest when both male and female were more than one year old ($24.4{\pm}11.08min$), although copulation took place regardless of partner's age. Females that mated twice within two days after estrus started or with two males had 100% pregnancy rate. In addition, the pregnancy rate was highest (87%) when both mating partners were more than one year old. Foxes preferred daytime to nighttime for mating, and thus mating usually took place on sunny days or between 10:00 and 12:00 on partly cloudy days. A male mated with different females for a maximum of five times, and the higher the mating frequency of a male, the longer the mating duration. Interest in mating decreased after three copulations in the case of males and after two copulations in the case of females. Males required at least 4 hours and 46 minutes between the first and second copulation. For this study, we collected reference data that might be applied to breeding programs for the red fox to secure the restoration of individuals of this important species.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.329-337
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• 2018

To increase the mating rate of Bombus ignitus used as insect pollinator, we investigated the sexual maturity time of B. ignitus. In investigating ovary development such as the number of eggs per ovariole and spermatheca size, the time of sexual maturity of queen was 10 days after eclosion. In case of male, the number of sperm was 246 thousand at immediately after eclosion, and was highest as 480 thousand at 9 days, and tended to show a dramatic decline at 35 days (87 thousand). The more mating time, the less the number of sperm. In consideration of number of sperms, the time of sexual maturity of male was 3-15 days after eclosion. In the sexual maturity time of queen in mating, the queen was not mated at immediately after eclosion, and showed a decrease in 20 days. In terms of the rate of mating and oviposition, the favorable time for mating of queen was 9-20 days. On the other hand, the male showed 3.3% of mating at immediately after ecolosion, showed the highest of 43.3% at 6 days after eclosion, and tended to decrease in 25 days. The sexual maturity time for mating of male was 6-20 days. In summary, our results indicate that sexual maturity time of B. ignitus in reproductive organs and mating is most favorable in 9-12 days after eclosion for queen and 6-9 days for male.

• The Plant Pathology Journal
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• v.17 no.5
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• pp.276-280
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• 2001

Fusarium isolates of Gibberella fujikuroi species complex were obtained from sorghum grown in five provinces of Korea in 1996 and 1997. These isolates were characterized based on their mating behavior, mycotoxin production, and vegetative compatibility. Only three mating populations (A, D, and F) were recovered from a total of 155 isolates examined. The relative frequency of the mating populations was significantly different: F was predominant (80%), while D and A were observed at low frequencies of 9% and 3%, respectively. Female fertile isolates were more common within F (44 our of 124) than D (2 out of 14), while none of the five A isolates were female fertile. The inbreeding effective population sizes ($\textrm{N}_e$)for mating type and male/hermaphrodite ratios in mating populations A and D produced significant amounts of fumonisins, while F isolates produced none or only traces of fumonisin B$_1$. In contrast. F isolates produced higher amounts of moniliformin (average of 3,820 ppm) than A and D isolates (averages of 77 and 1,819 ppm, respectively). Fifty-one isolates were tested for vegetative compatibility using nitrogen non-utilization mutants of each isolate, and 44 vegetative compatibility groups (VCGs) were identified. A single VC type (VC1) was found in all of the five A isolates examined. Six of the D isolates examined consisted of three VC types: two for VC2, two for VC3, and the rest for VC4. All of the F isolates tested were incompatible in every combination and , thus, each constituted a unique VCG.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.423-430
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• 2006

A total of 367 isolates of Phytophthora infestans was collected from the leaf samples of late blight disease from five provinces in Korea over the three growing seasons of 2002-2004. Of the 367 isolates, 337 isolates were of the A1 mating type, and 30 isolates were of A2 mating type, showing that the majority was A1 mating type. Profiles of Gpi and Pep defined four allozyme genotypes among the total of 367 isolates. All four allozyme genotypes could be distinguished on the basis of Gpi profiles alone, whereas all isolates were homozygous at the Pep locus (100/100). The mitochondrial DNA haplotype of all isolates were the IIa haplotype. Amplification of the genomic DNAs extracted from eight isolates of each mating type by polymerase chain reaction with the selected primer (OPC-5 primer) produced a total of 20 DNA bands, of which 11 bands were polymorphic. According to the RAPD analysis using the OPC-5 primer, 106 isolates including two standard isolates were separated into 8 groups at the similarity level of 92.5%. The RAPD groups were not correlated with the allozyme genotypes and the isolated locations. All of the eight RAPD groups were identified in Gangwon-do, suggesting that Gangwon-do is the center of origin of the P. infestans in Korea. A 600-bp DNA band generated with the OPC-5 primer was specific to A1 mating type isolates, but not detected with A2 mating type, showing that the specific PCR primer can distinguish different mating types in P. infestans.

• Korean Journal of Microbiology
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• v.37 no.4
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• pp.312-316
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• 2001

To improve the ethanol fermentability, four Saccharomyces yeast strains with efficient ethanol fermentability were subjected to rare-mating and protoplast fusion. Using these 4 strains, 5 different combinations of mating-pair or fusion-pair were constructed and their hybrids or fusants were obtained. From the statistical analysis of the results of the ethanol fermentation by the hybrids of the different mating-pair or fusion-pair, no difference was found in ethanol production, but [S. kluveri $khl{\times}S$ cerevisiae cp3] pair was shown to be the best combination which can produce high cell-viability. In fact, the clone No. 3 of the [S. kluveri $khl{\times}S$ cerevisiae cp3] pair was selected as the best strain which produced ethanol of 10.11% (w/v) or 12.81% (v/v) from 25% (w/v) glucose at $33^{\circ}C$ for 3 days with the residual sugar of 3.53% (w/v), viability of 62.65%, fermentation efficiency of 92.2%.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.502-509
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• 2005

Sexual reproduction plays an important role in the biology and epidemiology of oomycete plant pathogens such as the heterothallic species Phytophthora infestans. Recent worldwide dispersal of A2 mating type strains of P. infestans resulted in increased virulence, gene transfer, and genetic variation, creating new challenges for disease management. To develop a genetic assay for mating type identification in P. infestans, we used the Amplified Fragment Length Polymorphism (AFLP) technique. The primer combination E+AT/M+CTA detected a fragment specific to A1 mating type (Mat-A1) of P. infestans. This fragment was cloned and sequenced, and a pair of primers (INF-1, INF-2) were designed and used to differentiate P. infestans Mat-A1 from Mat-A2 strains. The Mat A1-specific fragment was detected using Southern blot analysis of PCR products amplified with primers INF-1 and INF-2 from genomic DNA of 14 P. infestans Mat-A1 strains, but not 13 P. infestans Mat-A2 strains or 8 other isolates representing several Phytophthora spp. Southern blot analysis of genomic DNAs of P. infestans isolates revealed a 1.6 kb restriction enzyme (EcoRI, BamHI, AvaI)-fragment only in Mat-A1 strains. The A1 mating type-specific primers amplified a unique band under stringent annealing temperatures of $63^{\circ}C-64^{\circ}C$, suggesting that this PCR assay could be developed into a useful method for mating type determination of P. infestans in field material.

• Mycobiology
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• v.29 no.3
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• pp.164-169
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• 2001

A new medium for studies of diversity among populations of $A_1\;and\;A_2$ mating types of Phytophthora infestans has been evolved. The rye A agar and V-8 juice agar media on which P. infestans grows well have been amended with rhizome powder of Cyperus rotundus. A total of 259 isolates of $A_1\;and\;A_2$ mating types representing Japan, Korea, India, Taiwan, Indonesia, Thailand, China, Nepal, U.K and Medico were screened for their growth response on these two media. Most of the A1 isolates did not grow well on them except Thailand while growth of $A_2$ mating types differed as some grew on it whereas others did not. It is quite likely that the populations of $A_2$ mating types that did not grow well on rhizome-amended medium are of different clonal lineage. This suggests that this medium can be used for the study of diversification among the isolates of the same or both the mating types as well as to detect the newly introduced genetically different isolates of P. infestans in a locality where it was not reported earlier.