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$^1$H nuclear magnetic resonance (NMR) experiments have been performed in the temperature range of 30 -- 300 K at 7 T to investigate the phase-dependent nature of the dynamic network of hydrogen bonds in a ((NH₄)₃H(SO₄)₂ single crystal. The crystal has six phases, which are ferroelectric, antiferroelectric, incommensurate, antiferroelectric, ferroelastic, and superionic with the respective transition temperatures of 63, 133, 139, 256 and 413 K. The spin-lattice relaxation time, T₁, of ¹H NMR is similar for the ammonium protons and the hydrogen-bond protons over the entire range of experimental temperatures. The T₁, of ¹H NMR gradually decreases down to 120 K and starts to steeply increase below 100 K. Then, the T₁ shows an abrupt decrease below 68 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. The ¹H NMR spectrum shifts to the high-frequency side at temperatures below 63 K due to the ferroelectric phase transition. This behavior of the T₁ and the spectrum confirms a dramatic change in the dynamics of hydrogen bonds associated with the ferroelectric phase transition at 63 K. $^1$H nuclear magnetic resonance (NMR) experiments have been performed in the temperature range of 30 -- 300 K at 7 T to investigate the phase-dependent nature of the dynamic network of hydrogen bonds in a ((NH₄)₃H(SO₄)₂ single crystal. The crystal has six phases, which are ferroelectric, antiferroelectric, incommensurate, antiferroelectric, ferroelastic, and superionic with the respective transition temperatures of 63, 133, 139, 256 and 413 K. The spin-lattice relaxation time, T₁, of ¹H NMR is similar for the ammonium protons and the hydrogen-bond protons over the entire range of experimental temperatures. The T₁, of ¹H NMR gradually decreases down to 120 K and starts to steeply increase below 100 K. Then, the T₁ shows an abrupt decrease below 68 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. The ¹H NMR spectrum shifts to the high-frequency side at temperatures below 63 K due to the ferroelectric phase transition. This behavior of the T₁ and the spectrum confirms a dramatic change in the dynamics of hydrogen bonds associated with the ferroelectric phase transition at 63 K.
본 연구는 저질 조사료의 에너지 가치 및 이용성을 평가하기 위해서 평균체중이 400㎏인 비육중인 Holstein 수소 4두를 공시하여 수행하였다. 공시동물은 각각 호흡대사실에서 4가지 사료를 4×4 Latin square 방법으로 공급받았다. 대조구는 농후사료(50%)와 Chinese wildrye hay(50%) 사료를 사용하였으며, 처리구는 저질 조사료구로서 무처리 볏짚(100%). 요소처리 볏짚(100%) 및 Chinese wildrye 건초(100%) 등 3가지 사료를 이용하였다. 처리구간의 에너지소화율에 있어서는 유의적 차이가 나타나지 알았지만, 대조구는 처리구에 비하여 에너지소화율이 유의적으로 높게 나타났다(P<0.05). Chinese wildrye 건초만을 에너지 섭취수준을 달리하여 급여한 결과, 에너지섭취가 증가할수록 에너지소화율은 감소하였다. 또한 같은 시험에서, 조사료 입자가 감소할수록 에너지소화율이 증가하는 경향을 보였다. 메탄과 뇨를 통한 에너지 손실에 있어서 처리구 및 대조구간에 차이는 없었지만, 사료중의 NDF가 증가할수록 메탄생성이 증가하였다. 요소처리 볏짚과 Chinese wildrye 건초 처리구간에 K_m과 K_f 모두 비슷하였으며, 대조구의 K_f가 가장 높게 나타났다. 단백질과 지방의 체내축적은 대조구, Chinese wildrye 건초구, 요소처리 볏짚구 및 무처리 볏짚구 순으로 높았다(P<0.05). 본 연구 결과는 화학처리 볏짚이 에너지소화율과 이용성에 면에서 무처리 볏짚보다 우수하게 나타났으며, 특히 값비싼 Chinese wildrye 건초를 에너지 이용성 면에서 값싼 화학처리 볏짚으로 대체할 수 있는 가능성을 보였다. Four steers weighing average of around 400㎏ were used in a 4 × 4 Latin square design to study energy values of low quality roughages. The energy digestibilities of rice straw, treated rice straw, and Chinese wildrye hay were not significantly different. However, the digestibility of control diet (concentrate + Chinese wildrye hay) was significantly higher (P<0.05) than those of low-quality roughages. The energy digestibility of rice straw was not improved due to the treatment of urea-Ca(OH)₂. The result showed N digestibility tended to be higher in the steer fed treated rice straw. When effects of particle sizes of low quality roughage, Chinese wildrye hay, on energy digestibility were determined, there were no significant differences in GE intakes among the treatments of four particle sizes of the hay. Results also showed that energy digestibility tended to slightly increase as the particle size reduced. Methane production in relation to DE was the highest in the treatment of untreated rice straw, and the lowest with control diet. However, there were no significant differences among four feeding treatments. Urine excretion showed similar trends with methane production. Total energy loss via methane and urine against DE were 12.26, 22.93, 16.35, and 14.88 % in control diet, untreated rice straw, treated rice straw, and Chinese wildrye hay, respectively. The efficiency of utilization of DE was not significantly different among the treatments, but untreated rice straw showed the lowest efficiency. The results also showed that K_m, among untreated rice straw, treated rice straw, and wildrye hay were similar. These data also showed that both the K_m, and K_f from treated rice straw and Chinese wildrye hay were remarkably similar. This similarity clearly showed that treated rice straw had no effect on the efficiency of ME utilization for either K_m and K_f in fattening steers. The K_f of control diet was the highest among the treatment. With regard to body deposition of protein and fat, the results showed the higher values in the order of control diet, Chinese wildrye hay, treated rice straw, and rice straw. Based on these observations, this study regarding energy utilization clearly shows that a portion of expensive forages in the diet could be replaced with low-quality roughages such as treated rice straw.
다결정시료(Fe₂O₃)1-x(Eu₂O₃)x (x=0.04와 0.06)계의 자기상 전이를 연구하기 위해 상온에서의 X선 회절, 액체질소온도에서 상온에 이르는 온도구간에서의 Mossbauer 분광과 약 8K에서 300K의 온도구간에서의 자기능률 측정방법을 사용하였다. X선 회절은 본 연구의 다결정시료가 a-Fe₂O₃와 동일한 rhombohedral결정구조를 가짐을 보인다. X선 회절선의 결과를 이용하여 비선형최소자승법을 써서 각 시료의 격자상수값을 구하였다. Mossbauer 분광결과는 자기상 전이가 255K<T<265K 온도 영역에서 일어남을 보인다. 온도영역 T<255K에서의 초미세 자기장의 온도 의존성에 반강자성 spinwave이론이 잘 적용됨을 보인다. 온도에 따른 magnetization의 변화로 자기상전이 온도를 관찰하였으며, 이 결과는 Mossbauer 분광 결과와 잘 일치 하였다. 상온에서의 hysteresis 곡선은 Eu농도가 증가함에 따라서 보자력이 증가하지만 자화와 잔류자화는 감소했음을 알 수 있었다. A study of magnetic transition for the polycrystalline (Fe₂O₃)1-x(Eu₂O₃)x (x=0.04 and 0.06) has been performed by the methods of X-ray diffraction at room temperature, Mossbauer spectroscopy within the temperature range from liquid nitrogen to room temperature, and a measurement of magnetic moment within temperature range of 8K∼300K. X-ray diffraction shows that the samples are in the same rhombohedral crystal structure as that of a-Fe₂O₃. The lattice parameter of the samples has been determined from X-ray diffraction patterns using computer with a progam of nonlinear square-fit. The Mossbauer results tell us that the magnetic transition of the samples occurs in the temperature region of 255K<T<265K. The temperature dependence of magnetic hyperfine field of the samples is in good agreement with a spin-wave theory for a antiferromagnetic phase within the temperature range from liquid nitrogen to 255K. The magnetic phase transition was observed by a temperature dependence of magnetization and the result was in good agreement with that of Mossbauer. Magnetic hysteresis curves indicated that the values of coercivity increase but that of magnetization and remanence of the samples decrease as increasing the concentration of Eu.
Genetic variants of αs₁-casein (αs₁-Cn) and K-casein (k-Cn) in milk proteins from 138 individual Holstein cattle in Korea were investigated by means of strach-gel-urea electrophoresis and the appearance of phenotypes, gene frequencies and genetic similarities were compared with those of foreign Holstein and of her breeds. The results are summarized as follows: 1. The milk proteins in cattle were controlled by codominant autosomal allelic genes of 9αs₁-Cn^A and αs₁-Cn^B(2 types), and K-Cn^A and K-Cn^B (2 types). 2. The distribution of phenotypes in each milk protein loci was αs₁-Cn BB 124, BC 14; K-Cn AA 76 Ab 49, BB 13. The number of phenotypes coxesponded closely to expectation of Hardy-Weinberg equilibrium (αs₁-Cn:0.7 $gt;P$gt;0.5, k-Cn;0.7$gt;P$gt;0.5). 3. Gene frequencies for genetic variants of the milk protein loci were analyzed. By the predominant allele in αs₁-Cn was αs₁-Cn B with a frequency of 0.949, whereas αs₁-CnC was in low gene frequency (0.051). Among the two alleles for K-Cn, K-Cn A gene showed to occur in high frequency (0.728). However, the Kin B was in low gene frequency (0.272).
전해질 공급제의 종류가 자돈의 성장과 대사에 미치는 영향을 조사하고자 라이신과 트립토판 등의 영양소가 극히 부족하고 전해질균형(Electrolyte balace: EB; Na+K-Cl meq/㎏)수준이 극히 낮은 (0 meq/㎏)전해질 공급제를 달리하여(NaHCo₃, KHCO₃, Na₂SO₄, K₂SO₄) EB 수준을 300 meq/㎏까지 맞춘 후 32일령의 3원교잡종(Largewhite × sandrace × Hampshire) 이유자돈 40두에 대하여 4주간의 사양시험을 실시하고, 체중 25㎏의 숫자돈 15두를 별도로 공시하여 4주간의 대사시험을 실시하였던 바 그 결과를 요약하면 다음과 같다. 1. 라이신 등 영양소가 극히 부족한 옥수수-옥수수글루텐 위주 사료에서 전해질 공급제를 달리하여 사료내 EB 수준을 EB 300 meq/㎏로 하였을 때 중성염구(Na₂SO₄, K₂SO₄)는 대조구 (EB 0 meq/㎏)에 비하여 일당 증체량이 유의적으로 높게 나타났지만 (K₂SO₄구:P<0.05), 알칼리성염(NaHCO₃, KHCO₃)구는 증체량 개선효과가 없었으며 중성염구는 알칼리성염구에 대하여도 유의적으로 높은 성적을 보였다(NaHCO₃ vs K₂SO₄: P<0.05). 한편 K 염구가 Na염구에 비하여 증체량이 수치상 높게 나타났으나 통계적인 유의성은 없었다. 사료섭취량은 증체량이 개선되는 경향에 맞추어 증가되는 양상을 보여 중성염구에서 높았으며 K₂SO₄구는 유의적으로 (P<0.05)높았다. 사료요구율도 증체 성적과 같이 중성염구에서 좋은 성적을 나타냈으나 처리간에 유의적인 차이는 없었다. 일당증체량은 암수 간에 다른 양상을 보여 수컷은 EB meq/㎏구에 비해 알칼리성염구 (EB 300)의 성적이 수치상 높았으나, 암컷의 경우에는 오히려 EB 0 meq/㎏구보다 낮은 성적을 보였다. 자돈이 알칼리성염구에서 성장 개선 효과를 보이지 못하고 중성염구에서 성장 효과를 보인 이유는 자돈의 일령 (체중)이 너무 어렸기 때문인 것으로 생각된다. 2. 뇨 성상은 사료내 전해질 공급원에 따라 영향을 받는 것으로 나타났다. 뇨 pH는 EB 0 meq/㎏인 대조구에 비하여 모든 전해질 공급제구에서 높게 나타나 NaHCO₃구와 KHCO₃구는 유의적으로 높은 (P<0.05) 수치를 보였다. N, Ca NH₃농도 및 24시간 배뇨량은 처리간에 일정한 경향이 없었으나, K, Na 및 Cl농도는 해당 공급제가 첨가된 처리구에서 높았으며 Mg농도는 EB 0 meq/㎏구에서 가장 높게 나타났다 (P<0.05). 3. 건물, 조단백질, 에너지 및 라이신 이용율은 EB 0 meq/㎏구에 비해 전해질 공급제구에서 높은 경향이었으나 유의성은 없었다. A pair of feeding and merabolic trial was conducted with the 32 day old 32 crossored (Largewhite × Landrace × Hampshire) weaning pigs to compare the effects of source of electrolyte on the performances of pigs fed deficient in lysine and tryptophane. Four electrolyte source (NaHCO₃, KHCO₃, Na₂SO₄, K₂SO₄) which respectively coverede0e0 meq/㎏ of electrolyte balance (EB) in test diets were compared using EB 0 meq/㎏ group as a negative control. When a corn-corn gluten meal base diet was supplemented with several sources of electrolyte in an amount of 300 meq/㎏, neutral salt groups (Na₂SO₄) resulted in significantly (p<0.05) higher weight gain than control group (EB 0), but alkaline salt groups (NaHCO₃, KHCO₃) did not show any improvements in weight gains as compared to control group. Body weight gain or neutral salt group was higher than that of alkaline salt groups (p<0.05; NaHCO₃ vs Na₂SO₄). The K salt group showed higher weight gain than that of Na salt groups without statistical significance. Feed consumption seemed to increased in neutral salt groups corresponding to increment in weight gain, and significantly (p<0.05) higher in K₂SO₄ group. Feed efficiency was not significantly influenced by treatment although there was a tendency of improvement in neutral salt group. Response of male and female pigs in weight gain appeared to be different ; weight gain of alkaline salt groups was higher than EB 0 group in male pigs, but lower in female pigs. The reason why the growth response was obtained in neutral salt group but not in alkaline salt group was assumed to be because of metabolic impact due to high level of alkaline salts imposed to too young pigs. Urine parameters were influenced by the source of electrolyte. Urinary pH was high in EB supplemented groups regardless of EB source as comparing to that in EB 0 group, and NaHCO₃ and KHCO₃ groups showed significantly (p< 0.05) higher values. There were no differences or tendencies among treatments in N, Ca, NH₃ contents and 24 hr. Urine volume, but K, Na, and Cl concentration were high in the groups fed diets added various electrolytes. Mg concentration was the highest at EB 0 group (P < 0.05). Digestibilities of dry matter (DM), crude protein (CP), energy and lysine were generally higher in EB supplemented groups without any significance. These result were not in accord with those of feeding trial, and it seemed that age and size of pigs used for feeding trial affected the results.
Genotypes of K-casein(K-CN) locus as a genetic marker linked to quantitative trait loci affecting traits of economic importance in dairy cattle were determined by PCR-RFLP method. Genomic DNA was prepared from blood of Holstein cows. The PCR was used to amplify an 874 by region between nucleotides 10592 and 11466 from exon IV to intron IV of the bovine K-CN gene using sense primer(5'-GTGCTGAGTAGGTATCCTAG-3') and antisense primer(5'GTAGAGTGCAACAACACTGG-3'). After amplification, PCR products were digested with four restriction enzymes, Hind III, Rsa I, Taq I, and Pst I, and the fragments were separated by agarose gel electrophoresis for RFLP analysis of K-CN locus. In addition to screening for the known Hind III and Rsa I restriction site polymorphisms of K-CN locus, we have found additional RFLPs specific for the K-CN A and B alleles in Taca I and Pst I enzymes. The amplified DNA product digested with each restriction enzyme generated specific RFLP pattern that allowed precise identification of K-CN AA, BB or AB genotypes. The K-CN genotypes determined for cows by the PCR-RFLP method agreed completely with the phenotypes obtained from milk samples of the same individuals. Thus, PCR amplification and RFLP analysis was shown to be a rapid and sensitive method for the discrimination of K-CN genotypes directly at the DNA level in dairy cattle of any age or sex. Consequently, the PCR-RFLP method presented in this study can be used as a valuable tool for early selection of AI bulls and calves with desirable K-CN B gene or K-CN BB genotype affecting superior milk production traits for genetic improvement of Holstein dairy cattle.
<P>Potassium depletion (K?-D) induces hypertrophy and hyperplasia of collecting duct cells, and potassium repletion (K?-R) induces regression of these changes. The purpose of this study was to examine the time courses of the changes in cellular composition, the origin of intercalated cells (ICs) and the mechanism responsible for these changes. SD rats received K?-depleted diets for 1, 7, or 14 days. After K?-D for 14 days some of the rats received normal diets for 1, 3, 5, or 7 days. In the inner stripe of the outer medulla, K?-D increased significantly the number and proportion of H?-ATPase-positive ICs, but decreased the proportion of H?-ATPase-negative principal cells (PCs). However, proliferation was limited to H?-ATPase-negative PCs. During K?-R, the cellular composition was recovered to control level. Apoptosis increased during K?-R and exclusively limited in H?-ATPase-negative PCs. Double immunolabeling with antibodies to PC and IC markers identified both cells negative or positive for all markers during both K?-D and K?-R. Electron microscopic observation showed that ultrastructure of AE1-positive some cells were similar to AE1-negative some cells during K?-R. LC3 protein expression increased significantly and autophagic vacuoles appeared particularly in PCs on days 14 of K?-D and in ICs on days 3 of K?-R. These results suggest that PCs and ICs may interconvert in response to changes in dietary K+ availability and that autophagic pathways may be involved in the interconversion.</P>
1H nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal (NH4)3H(SO4)2. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the 1H NMR MAS spectrum at 340 K. As temperature decreases, the 1H NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of T1 for ammonium and hydrogen-bond protons are similar in the whole range of temperature. T1 of 1H NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then T1 shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and T1 clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.
<P>Abstract</P><P>Aims: </P><P>Screening and partial characterization of a bacteriocin produced by <I>Pediococcus pentosaceus</I> K23-2 isolated from Kimchi, a traditional Korean fermented vegetable.</P><P>Methods and Results: </P><P>A total of 1000 lactic acid bacteria were isolated from various Kimchi samples and screened for the production of bacteriocin. Pediocin K23-2, a bacteriocin produced by the <I>Pediococcus pentosaceus</I> K23-2 strain, showed strong inhibitory activity against <I>Listeria monocytogenes</I>. The bacteriocin activity remained unchanged after 15 min of heat treatment at 121°C or exposure to organic solvents; however, it diminished after treatment with proteolytic enzymes. The bacteriocin was maximally produced at 37°C, when the pH of the culture broth was maintained at 5·0 during the fermentation, although the optimum pH for growth was 7·0. The molecular weight of the bacteriocin was about 5 kDa according to a tricine SDS-PAGE analysis.</P><P>Conclusions: </P><P><I>Pediococcus pentosaceus</I> K23-2 isolated from Kimchi produces a bacteriocin, which shares similar characteristics to the Class IIa bacteriocins. The bacteriocin is heat stable and shows wide antimicrobial activity against Gram-positive bacteria, especially <I>L. monocytogenes</I>.</P><P>Significance and Impact of the Study: </P><P>Pediocin K23-2 and pediocin K23-2-producing <I>P. pentosaceus</I> K23-2 could potentially be used in the food and feed industries as natural biopreservatives, and for probiotic application to humans or livestock.</P>
[ $^1H$ ] nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal $(NH_4)_3H(SO_4)_2$. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the $^1H$ NMR MAS spectrum at 340 K. As temperature decreases, the $^1H$ NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of $T_1$ for ammonium and hydrogen-bond protons are similar in the whole range of temperature. $T_1$ of $^1H$ NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then $T_1$ shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and $T_1$ clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.