Study on the effect of doxorubicin on expressions of genes encoding myocardial sarcoplasmic reticulum Ca^2＋ transport proteins and the effect of taurine on myocardial protection in rabbits

To investigate the effect of doxorubicin(DOX) on gene expression of the myocardial sarcoplasmic reticulum (SR)Ca^2 transport proteins and the mechanism of taurine(Tau) protecting cardiac muscle cells, 9 rabbits were injected with DOX , 8 rabbits with DOX and Tau, and 9 rabbits with normal saline. Cardiac function , concentration of calcium in cardiomyocytes ( Myo [ Ca^2 ]i ), activity of SR Ca^2 -ATPase (SERCA2a) , level of SERCA2a mRNA and Ca^2 released channels(RYR2) mRNA were detected. The left ventricle tissues were observed by electron microscopy. The results showed that cardiac index, left ventricular systolic pressure, activity of SR Ca^2 -ATPase and level of SERCA2a mRNA decreased , while Myo[ Ca^2 ]i increased in DOX-treated rabbits. DOX could not affect the level of RYR2 mRNA. Tau intervention could alleviate the increase of left ventricular diastolic pressure, Myo[ Ca^2 ] i and the decrease of SERCA2a mRNA induced by doxorubicin. Tile results suggested that downregulation of SERCA2a gene expression was an important mechanism of DOX-induced cardiomyopathy and that Tau could partially improve the heart function by reducing calcium overload and alleviating downregulation of SERCA2a mRNA.     

Purification and characterization of myosin from wheat mitochondria

Myosin was purified from wheat mitochondria using DE-52 anion exchange chromatography and Sephacryl S-300 gel filtration. The molecular weight of its heavy chain is about 210 ku, similar to that of muscle myosin Ⅱ(205 ku), and it could be recognized by the polyclonal antibodies against human skeletal muscle myosin Ⅱ. The ATPase activity of the mitochondrial myosin stimulated by F-actin from chicken muscle is 202.5 nmoles Pi/min·mg. The mitochondrial myosin could be activated by Ca²⁺ and was not inhibited by Ca²⁺ at high concentration. The results demonstrate that the myosin of wheat mitochondria shares some similarities with the skeletal muscle myosin Ⅱ.     

Mineral sulphide-lime reactions and effect of CaO/C mole ratio during carbothermic reduction of complex mineral sulphides

Mineral sulphide (MS)-lime (CaO) ion exchange reactions (MS + CaO = MO + CaS) and the effect of CaO/C mole ratio during carbothermic reduction (MS + CaO + C = M + CaS + CO(g)) were investigated for complex froth flotation mineral sulphide concentrates. Phases in the partially and fully reacted samples were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The primary phases during mineral sulphide-lime ion exchange reactions are Fe₃O₄, CaSO₄ Cu₂S, and CaS. A complex liquid phase of Ca₂CuFeO₃S forms during mineral sulphide-lime exchange reactions above 1173 K. The formation mechanisms of Ca₂CuFeO₃S liquid phase are determined by characterising the partially reacted samples. The reduction rate and extent of mineral sulphides in the presence of CaO and C increase with the increase in CaO/C ratio. The metallic phases are surrounded by the CaS rich phase at CaO/C > 1, but the metallic phases and CaS are found as separate phases at CaO/C < 1. Experimental results show that the stoichiometric ratio of carbon should be slightly higher than that of CaO. The reactions between CaO and gangue minerals (SiO₂ and Al₂O₃) are only observed at CaO/C > 1 and the reacted samples are excessively sintered.     

Adrenomedullin inhibits the endothelin production induced by urotensin II in rat vascular smooth muscle cells

The aim of this study was to observe the effects of adrenomedullin (ADM) on endothelin (ET) production induced by urotensin Ⅱ (UⅡ) in rat vascular smooth muscle cells (VSMCs). Cultured VSMCs which were incubated with UⅡ (10^-8 mol/L) and with various concentrations of ADM were used to measure the VSMCs ³H-TdR incorpora- tion, the activity of extracellular signal-regulated kinase (ERK), the amount of ET mRNA and ET production in VSMCs. In this work we found that incubation with UⅡ(10^-8 mol/L) increased obviously the amount of ET mRNA in VSMCs and ET production in medium, however, coincubation with ADM (10^-10—10^-8 mol/L) and UⅡ(10^-8 mol/L) reduced the amount of ET mRNA by 15%, 24% and 45% (P< 0.01) respectively, compared with UⅡ alone. The content of ET in medium was 14.13, 11.38 and 11.00 pg/mL. ADM alone (10^-8 mol/L) had no effect on ET production in VSMCs. UⅡ (10^-8 mol/L) promoted the 3H-TdR incorpo- ration and activity of ERK in VSMCs. ADM inhibited VSMCs 3H-TdR incorporation and activation of ERK in a concentration-dependent manner. Compared with UⅡ group, after coincubation with ADM (10^-10—10^-8 mol/L) and UⅡ (10^-8 mol/L) the VSMCs 3H-TdR incorporation was decreased by 7% (P > 0.05), 32% (P < 0.05) and 41% (P < 0.01), respectively, and the activity of ERK was decreased by 24% (P > 0.05), 32% (P < 0.05) and 36% (P < 0.05), re- spectively, in a concentration-dependent manner. The results show that in cultured VSMCs ADM inhibits ET mRNA expression, ET production and proliferation stimulated by UⅡ, and that inhibitory effect of ADM on UⅡ bioaction could be mediated through inhibiting MAPK pathway.     

Formation mechanism of calcium hexaluminate

To investigate the formation mechanism of calcium hexaluminate (CaAl₁₂O₁₉, CA₆), the analytically pure alumina and calcia used as raw materials were mixed in CaO/Al₂O₃ ratio of 12.57:137.43 by mass. The raw materials were ball-milled and shaped into green specimens, and fired at 1300–1600°C. Then, the phase composition and microstructure evolution of the fired specimen were studied, and a first principle calculation was performed. The results show that in the reaction system of CaO and Al₂O₃, a small amount of CA₆ forms at 1300°C, and greater amounts are formed at 1400°C and higher temperatures. The reaction is as follows: CaO·2Al₂O₃ (CA₂) + 4Al₂O₃ → CA₆. The diffusions of Ca2+ in CA₂ towards Al₂O₃ and Al3+ in Al₂O₃ towards CA₂ change the structures in different degrees of difficulty. Compared with the difficulty of structural change and the corresponding lattice energy change, it is deduced that the main formation mechanism is the diffusion of Ca2+ in CA₂ towards Al₂O₃.     

Optimal time for mesenchymal stem cell transplantation in rats with myocardial infarction

Background： Bone marrow mesenchymal stem cell （MSC） transplantation is a promising strategy in the treatment of myocardial infarction （MI）. However, the time for transplanting cells remains controversial. The aim of this study was to find an optimal time point for cell transplantation. Methods： MSCs were isolated and cultured from Sprague-Dawley （SD） rats. MI model was set up in SD rats by permanent ligation of left anterior descending coronary artery. MSCs were directly injected into the infarct border zone at 1 h, 1 week and 2 weeks after MI, respectively. Sham-operated and MI control groups received equal volume of phosphate buffered saline （PBS）. At 4 weeks after MI, cardiac function was assessed by echocardiography; vessel density was analyzed on hematoxylin-eosin stained slides by light microscopy; the apoptosis of cardiomyocytes was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling （TUNEL） assay; the expressions of proteins were analyzed by Western blot. Results： MSC transplantation improved cardiac function, reduced the apoptosis of cardiomyocytes and increased vessel density. These benefits were more obvious in 1-week group than in 1-h and 2-week groups. There are more obvious increases in the ratio of bcl-2/bax and the expression of vascular endothelial growth factor （VEGF） and more obvious decreases in the expression of cleaved-caspase-3 in 1-week group than those in other two groups. Conclusion： MSC transplantation was beneficial for the recovery of cardiac function. MSC transplantation at 1 week post-MI exerted the best effects on increases of cardiac function, anti-apoptosis and angiogenesis.     

Preventive effects of Xin-Kang oral liquid on viral myocarditis in mice

To investigate the preventive effects of Xin-Kang oral liquid on myocarditis induced by Coxsakie virus B ( CVB) > the medicine was given to mice two days prior to the challenge of mice with the CVB to induce myocarditis. The oral liquid was continuously given to mice for 20 days and quantitative histological changes at various stages of the myocarditis were observed. The pathological changes on the cardiac surface were significantly reduced in Xin-Kang treated mice compared to those in control group (P<0. 01). and the occurrence of severe myocardium damage ( massive cardiac tissue death and degradation) was less in the Xin-Kang group than the groups either challenged with CVB or treated with interferon. The group treated with 0. 015g per gram body weight per day showed significant improvement over the viral group (P<0.01). The results proved that Xin-Kang could protect the cardiac muscle from viral infection and accelerate recovery of damaged cardiac tissue.     

Multiple intracellular signallings involved in regulation of on channels by GH releasing or inhibitory hormones in pituitary somatotropes

Influx of Ca2-via Ca2+ channels is the major step triggering exocytosis of pituitary somatotropes to release growth hormone (GH). Voltage-gated Ca2+ and K+ channels, the primary determinants of the influx of Ca2+ in somatotropes, are regulated by GH-releasing hornone (GHRH) and somatostatin (SRIF) through G protein-coupled signalling systems. Using whole-cell patch-clamp techniques, the changes of the Ca2+ and K+ currents in primary cultured somatotropes were recorded and signalling systems were studied using pharmacological reagents and intracellular dialysis of non-permeable molecules including antibodies and antisense oligonucleotides. GHRH increased both L-and T-types Ca2+ currents and decreased transient (I4) and delayed rectified (Ik) K+ currents. The increase in Ca2+ currents by GHRH was mediated by cAMP/protein kinase A system but the decrease in K+ currents required normal function of protein kinase C system. The GHRH-induced alteration of Ca2+ and K+ currents augments the influx of Ca2+ , leading to an increase in the [ Ca2+ ]I and the GH secretion. In contrary, a significant reduction in Ca2+ currents and increase in K currents were obtained in response to SRIF. The ion channel response to SRIF was demonstrated as a membrane delimited pathway and can be recorded by classic whole-cell configuration, Intracellular dialysis of anti-αi3 antibodies attenuated the increase in K + currents by SRIF whereas anti-αo antibodies blocked the reduction in the Ca2+ current by SRIF. Dialysis of antisense oligonucleotides specific for αo2 sub-units also attenuated the inhibition of SRIF on the Ca2+current. The Gi3 protein mediated the increase in K + currents and the Go2 protein mediated the reduction in the Ca2 +current by SRIF. The SRIF-induced alteration of Ca2 + and K + currents diminished the influx of Ca2+ , leading to a decrease in the [ Ca2+ ]I and the GH secretion. It is therefore concluded that multiple signalling systems are employed in the ion channel response to GHRH or SRIF in somatotropes, which leads to an increase or decrease in the GH secretion.     

Actin and myosin during pollen germination

Actin and myosin from pollen tubes of Lilium davidii were studied by using immunoblotting, Dot_Blot and myosin Ca 2+_ATPase analysis. On immunoblotting of the total soluble pollen tube proteins, anti_α_actin antibody labelled a polypeptide approximately 43 ku, which is considered to be the actin of lily. The mRNA encoding actin in ungerminated pollen and germinated pollen were both undetectable in our experiments. A myosin exhibited Ca 2+_ATPase activity, with a native molecular weight of 460 ku has been identified by using immunoblotting. A polypeptide of about 205 ku and a polypeptide of about 20 ku were the heavy chain and a set of light chain of the myosin, which can crossreact with anti_skeletal muscle myosin heavy chain monoclonal antibody and anti_skeletal muscle myosin light chain (20 ku) monoclonal antibody, respectively. The Ca 2+_ATPase activities of myosin in crude extracts of germinated pollen were positively related to the growth rates of pollen tubes.     

Effect of calcium ions on the secondary structures of photosystemⅡ and its relations with photoinhibition

Calcium ions play an important role in the oxygen_evolving process of photosystem Ⅱ as demonstrated in many experiments. The changes of the secondary structures of PS Ⅱ induced by the depletion of Ca 2+ were reported. The results indicated that the removal of Ca 2+ led to the transition of α helix to turns and sheet structures. While Ca 2+ was re_added to the media, only the structures changed to turns could be recovered. The protein conformational changes of PS Ⅱ during the donor side photoinhibition induced by the depletion of Ca 2+ were also studied. This showed that the protein conformational changes differed between the control and Ca 2+ _depleted samples in a short period of illumination (within 10 min). However, the changes became similar when the illumination time was increased.     

Action mechanisms of a new erythrocyte-derived depressing factor

To investigate the action mechanisms of a new erythrocyte-derived depressing factor (EDDF), the focus is placed on the effect of EDDF on both cytosolic and nuclear free calcium (Ca²⁺) transportation in vascular smooth muscle cell (VSMC), as well as the apoptosis and cell cycle of VSMC of rats. EDDF has been extracted from human erythrocytes. The changes of Ca²⁺ levels in cytoplasm ([Ca²⁺]_i) and nucleus ([Ca²⁺]_n) have been observed using a laser scanning confocal microscope together with fluo-3/AM as a calcium indicator. Flow cytometric technique was used to study the effect of EDDF on cell cycle and apoptosis of VSMC. [Ca²⁺], and [Ca²⁺]_n were significantly decreased through several different pathways: ( i ) it reduced the Ca²⁺ influx by blocking L-type voltage-dependent calcium channel (L-VDC) and R-type voltage-dependent calcium channel (R-VDC); (ii) it inhibited the Ca²⁺ release from inositol 1, 4, 5-trisphosphate (IP₃) sensitive calcium store; and (iii) activated Ca²⁺-ATPase of sarcoplasmic reticulum (SR) and promoted the transportation of Ca²⁺ from cytoplasm to SR. However, EDDF seemed to have little inhibitory effect on the Ca²⁺ release from ryonodine sensitive calcium pool. It was also found that EDDF (10⁻⁴ g/mL) significantly decreased the proportion of S phase of human umbilical vein (HUV) and inhibited the proliferation of VSMC induced by angiotensin II (Angll, 10⁻⁵ mol/L). The apopotosis did not occur when VSMC was cultured under normal condition. While VSMC apoptosis was induced by Angll (10⁻⁵ mol/L) and EDDF (10⁻⁴ g/mL) seemed to have little effect on it. The inhibitory effect of EDDF on the elevation of [Ca²⁺]_i and [Ca²⁺]_n of VSMC might play an essential role in its action mechanisms and the ways it affects the Ca²⁺ handling of VSMC demonstrate that EDDF was different from other endogenous blood pressure regulators and some known antihypertensive drugs. EDDF could inhibit the proliferation of VSMC, which indicated that it might be beneficial to the prevention and treatment of hypertension and arteriosclerosis.     

Icariin suppresses bone resorption activity of rabbit osteoclasts in vitro

The effect of icariin on the bone resorption activity of rabbit osteoclasts is assessed in vitro. Osteoclasts were isolated from Japanese white rabbits and cultured on plates with a sterilized bone slice in each well. After treatment with icariin at various concentrations, the bone resorption activity of osteoclasts was evaluated by examining pit areas, superoxide anion (·O2-) generation, size and number of actin rings and intracellular calcium concentration [Ca2 ]i. As revealed by these data, icariin elicited continuous decline of [Ca2 ]i, making actin ring constricted and ·O2- generation decreased. These events resulted in smaller and fewer pits which indicate suppressed bone resorption activity of rabbit osteoclasts by icariin.     

Nitric oxide suppresses stomatal opening by inhibiting inward-rectifying K<Stack><Subscript>in</Subscript><Superscript>+</Superscript></Stack> channels in <Emphasis Type="Italic">Arabidopsis</Emphasis> guard cells

We explore nitric oxide （NO） effect on K^＋in, channels in Arabidopsis guard cells. We observed NO inhibited K^＋in, currents when Ca^2＋ chelator EGTA （Ethylene glycol-bis（2-aminoethylether）-N,N,N′,N;tetraacetic acid） was not added in the pipette solution; K^＋in currents were not sensitive to NO when cytosolic Ca^2＋ was chelated by EGTA. NO inhibited the Arabidopsis stomatal opening, but when EGTA was added in the bath solution, inhibition effect of NO on stomatal opening vanished. Thus, it implies that NO elevates cytosolic Ca^2＋ by activating plasma membrane Ca^2＋ channels firstly, then inactivates K^＋in, chartnels, resulting in stomatal opening suppressed subsequently.     

Correlation between platelet gelsolin levels and different types of coronary heart disease

Gelsolin is an important cytoskeletal protein of platelets and studies have shown a close relationship between gelsolin and cardiovascular disease.However,the role of gelsolin in the development of coronary heart disease(CHD) is unclear.In this study,we record the distribution of gelsolin in human platelets and plasma and its association with different types of CHD.This study included 114 cases,with 33 stable angina pectoris(SAP) cases,81 acute coronary syndrome(ACS) cases—composed of 39 unstable angina pectoris(UAP) and 42 acute myocardial infarction(AMI) cases,and 31 healthy control participants.Gelsolin concentration in platelet rich plasma(PRP) and platelet poor plasma(PPP),actin filament(F-actin) and Gc-globulin of PPP were determined by enzyme-linked immunoadsorbent assay(ELISA).The fluorescence intensity of CD62p and cytoplasmic calcium([Ca2+] i) in human platelets measured by flow cytometry.We also used turbidimetry to detect the platelet aggregation rate(PAR).We analyzed the correlation between platelet gelsolin concentration and CD62p or plasma F-actin levels among each different patient group.Compared with the control group,the gelsolin level in PRP of UAP and AMI groups increased significantly(P<0.01),while the gelsolin level in PPP of all the three patient groups decreased markedly(P<0.01),and the CD62p,PAR,[Ca2+] i of platelets,F-actin and Gc-globulin of the UAP and AMI groups increased significantly(P<0.01).Compared with the SAP group,the gelsolin level in PRP,the PAR,[Ca2+] i of platelets and CD62p of other two groups increased significantly(P<0.01),F-actin of the AMI group increased markedly(P<0.01).Platelet cytoskeleton protein dynamics vary among the different types of CHD.Platelet gelsolin levels are markedly increased and accompanied by increased platelet activity,F-actin and [Ca2+] i of ACS patients,while gelsolin levels in PPP are markedly lower.Abnormally increased platelet gelsolin levels show high positive correlation with the level of platelet activity.Therefore,platelet gelsolin might be a novel molecular marker and/or a new potential therapeutic target of anti-platelet therapy of ACS.     

Adsorption and reduction of palladium (Pd<Superscript>2+</Superscript>) by <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> R08

Preliminary study on the mechanism of Pd²⁺ biosorption by resting cells of Bacillus licheniformis R08 biomass has been carried out by means of chemical kinetics and AAS, TEM, XRD and FTIR methods. The results showed that at 30℃ and pH 3.5, when dry R08 biomass powder (800 mg/L) was mixed with Pd²⁺ (100 mg/L) for 45 min, the rate constant k of biosorption of Pd²⁺ attained a maximum of 5.97×10^-2 min^-1 and the half life period of the reaction reached 12 min. The part of Pd²⁺ adsorbed by R08 biomass was reduced to elemental, cell-bound Pd⁰ at the same condition. The cell wall of R08 biomass was the primary location for accumulating Pd²⁺ , and aldoses, i. e. hydrolysate of a part of polysaccharides on the peptidoglycan layer in the acidic medium, serving as the electron donor, in situ reduced the Pd²⁺ to Pd⁰.     

Near-infrared to visible up-conversion emissions of Er^3＋ doped Al2O3 powders derived from the sol-gel method

The Er3 doped Al2O3 powders were prepared by the sol-gel method using the aluminium isopropoxide [Al(OC3H7)3]-derived Al2O3 sols with addition of the erbium nitrate [Er(NO3)3.5H2O]. The different phase structure, including three crystalline types of (Al,Er)2O3 phases, γ, θ, α, and two Er-Al-O phases, ErAlO3 and Al10Er6O24, was obtained with the 1 mol% Er3 doped Al2O3 powders at the different sintering temperatures of 600―1200℃. The green and red up-conversion emissions centered at about 523, 545 and 660 nm, corresponding respectively to the 2H11/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3 , were detected by a 978 nm semiconductor laser diodes excitation. The phase structure and OH content had evident influence on the up-conversion emissions intensity. The maximum intensities of both the green and red emissions were obtained respectively for the Er3 doped Al2O3 powders sintered at 1200 ℃, which was composed mainly of α-(Al,Er)2O3, less of ErAlO3 and Al10Er6O24 phases, and with the least OH content. The two-photon absorption up-conversion process was involved in the green and red up-conversion emissions of the Er3 doped Al2O3 powders.     

Integral Points on a Class of Elliptic Curve

0 IntroductionZasegairerc[h1]fodre sbcirgibientde gsreavle rpaolin tmse tohnocdsert waihnicehlli ppetircm citur ovnese btyogiving the upper bound of solution. Unfortunately,this upperbound was verylarge andsometi mes beyondthe range of com-puter searching.For a particular elliptic curvey2=x3-30x+133(1)he mentioned he can find all integral points and the largestpoint is (x,y) =(5 143 326 ,±11 664 498 677) by using Mas-ser and W櫣stholz bounds on elliptic logarithms .Although recent results on…     

Carboxymethytl Pachymaram Up-Regulates Dendritic Cell＇s Function in Hepatitis B Virus Transgenic Mice

The effect of carboxymethytl pachymaram (CMP) on the function of dendritic cells(DCs) derived from spleens of hepatitis B virus transgenic mice are studied in vitro. The phenotypes of DCs are tested by flow cytometry (FCM), cytokines measured by ELISA. The expression of DCs’ phenotypes in HBV transgenic mice are low (CD80⁺CD11c⁺:59.12±11.53 vs 9.60±4.53, p<0.01; CD80⁺ MHC-II⁺: 44.86±12.31 vs 9.80±5.72, p<0.01, normal mice vs HBV transgenic mice), the ability of DCs stimulating T lymphocytes proliferation decreases (0.37±0.11 vs 0.20±0.11, p<0.05, normal mice vs HBV transgenic mice), levels of IL-12 and IFN-γ decrease whereas the level of IL-10 increases; CMP can enhance DCs’ ability of stimulating T lymphocytes proliferation, facilitate the secretion of IL-12 and IFN-γ, inhibit the secretion of IL-10, thus up regulates DCs function. The results show a good prospective use of CMP on the treatment of chronic hepatitis B. Biography: HOU Anji (1963–), male, Ph.D. candidate, Associate professor, research direction: clinical virology.     

Foliar δ^13C and δ^15N values of C3 plants in the Ethiopia Rift Valley and their environmental controls

The foliar C and N stable isotopic compositions （δ^13C and δ^15N） and the relationships between these compositions and environmental factors of C3 plants in the Ethiopia Rift Valley were investigated. There were three distribution patterns for foliar δ^13C with mean values of -26.7‰±0.4‰, -29.7‰ ±0.6‰ , and -26.9‰± 1.2‰ in cold-moist, temperate-moist, and arid-hot environments, respectively. The δ^15N values ranged from -1.4‰ ±1.7‰ to 14.3‰ ± 0.1‰, with higher values under arid-hot conditions and the lowest values in plants growing at higher altitudes under cold-moist conditions. A strong negative relationship between mean annual precipitation and δ^15N explained more than half of the observed variation in the δ^15N values （r2= 0.54, P 〈 0.001）; a modest positive relationship was also found between δ^15N and temperature （r2 = 0.32, P 〈 0.01）. A weakly positive relationship existed between δ^13C and temperature, and changes in δ^13C values with precipitation and altitude followed quadratic curves. This suggests a shift in the effects of water and heat conditions caused by altitude on carbon isotopic discrimination.     

Mapping of genetic modifiers of <Emphasis Type="Italic">Plcd1</Emphasis> in scant hair mice (<Emphasis Type="Italic">snthr</Emphasis><Superscript><Emphasis Type="Italic">1Bao</Emphasis></Superscript>)

The scant hair mutant mouse (locus symbol: snthr ^1Bao ) is a recessive mutation that originated in an ethylnitrosourea chemical carcinogenesis study using the DBA/2J inbred strain. The gene responsible for the mutation was previously determined to be phospholipase C, delta 1 (Plcd1; mutant allele symbol Plcd1 ^snthr1Bao ). To map the modifiers of Plcd1, an intercross (DBA/2J-snthr ^1Bao /snthr ^1Bao × C57BL/6J+/+) was conducted. The F2 mutant progeny exhibited a variety of alopecia phenotypes; all F2 mutants (n=507) were classified into 3 groups (mild, moderate, and severe alopecia) and genotyped based on 96 microsatellites. A major QTL was identified on mouse chromosome (mChr) 15 at 12 cM with an LOD score greater than 7 (P < 0.0001). Three minor QTLs were detected on mChr 2, 5, and 7 at 40, 84 and 48 cM, respectively. The QTLs on mChr 7 and 15 were associated with minor alopecia while the QTLs on mChr 2 and 5 were associated with moderate to severe alopecia. No antagonistic or synergistic effects among or between the 4 QTLs were found. Integrating the functions of the 4 potential regulatory QTLs and mutant Plcd1 ^snthr1Bao , we found that these QTLs might contribute to variations of scant hair severity by altering the Ca²⁺ signal pathways in mouse skin.