The Lower Cretaceous Patuxent Formation Ichnofauna of Virginia

The vertebrate fauna from the Lower Cretaceous Patuxent Formation of Virginia is composed of a single partial fish impression from the James River at Dutch Gap and a diverse tetrapod ichnofauna from near Fredericksburg that includes trace fossils made by frogs, turtles, theropods, sauropods, ankylosaurs, and ornithopods. The footprints occur on overbank deposits preserved locally within a fluvial braided-stream sequence that formed near the western border of the Early Cretaceous Atlantic Coastal Plain.     

In vivo progestin treatments inhibit nitric oxide and endothelin-1-induced bovine endometrial prostaglandin (PG) E (PGE) secretion in vitro

Synchronization of estrus with progestins in cows has been reported to inhibit nitric oxide (NO) and endothelin-1 (ET-1)-stimulated bovine luteal PGE secretion without affecting prostaglandin F2alpha (PGF2alpha) secretion in vitro [Weems YS, Randel RD, Tatman S, Lewis A, Neuendorff DA, Weems CW. Does estrous synchronization affect corpus luteum (CL) function? Prostaglandins Other Lipid Mediat 2004;74:45-59]. Two experiments were conducted to determine the effects of NO donors, endothelin-1 (ET-1), and NO synthase (NOS) inhibitors on bovine caruncular endometrial secretion of PGE and PGF2alpha in vitro. In Experiment 1, estrus was synchronized in Brahman cows with Synchromate-B ear implants, which contained the synthetic progestin norgestamet. Days 14-15 caruncular endometrial slices were weighed, diced, and incubated in vitro with treatments. Treatments (100 ng/ml) were: Vehicle (control), l-NAME (NOS inhibitor), l-NMMA (NOS inhibitor), DETA (control), DETA-NONOate (NO donor), sodium nitroprusside (NO donor), or ET-1. In Experiment 2, estrus was synchronized in Brahman cows with either Lutalyse (PGF2alpha) or a controlled intravaginal drug releasing device (CIDR-containing progesterone) or estrus was not synchronized. Days 14-15 caruncular endometrial slices were weighed, diced, and incubated in vitro with treatments. Treatments (100 ng/ml) were: vehicle, l-NAME, l-NMMA, DETA, DETA-NONOate, sodium nitroprusside, SNAP (NO donor) or ET-1. Tissues were incubated in M-199 for 1h without treatments and with treatments for 4 and 8h in both experiments. Media were analyzed for concentrations of PGE and PGF2alpha by radioimmunoassay (RIA). Hormone data in Experiments 1 and 2 were analyzed by 2x7 and 3x2x8 factorial design for ANOVA, respectively. Concentrations of PGE and PGF2alpha in media increased (P< or =0.05) from 4 to 8 h regardless of treatment group in Experiment 1, but did not differ (P> or =0.05) among treatments. In Experiment 2, concentrations of PGE and PGF2alpha increased (P< or =0.05) with time in all treatment groups of all three synchronization regimens. DETA-NONOate, SNAP, and sodium nitroprusside (NO donors) and ET-1 increased caruncular endometrial (P< or =0.05) secretion of PGE2 in unsynchronized and Lutalyse synchronized cows, but not when estrus was synchronized with a CIDR (P> or =0.05). No treatment increased (P> or =0.05) PGF2alpha in any synchronization regimen. It is concluded that norgestamet in Synchromate-B ear implants or progesterone in a CIDR alters NO or ET-1-induced secretion of PGE by bovine caruncular endometrium and could interfere with implantation by altering the PGE:PGF2alpha ratio resulting in increased embryonic losses during early pregnancy.     

Atypical protein kinase Ciota plays a critical role in human lung cancer cell growth and tumorigenicity

Atypical protein kinase C (aPKC) isozymes function in epithelial cell polarity, proliferation, and survival and have been implicated in cellular transformation. However, the role of these enzymes in human cancer is largely unexplored. Here, we report that aPKCiota is highly expressed in human non-small cell lung cancer cell lines, whereas the closely related aPKC isozyme PKCzeta is undetectable in these cells. Disruption of PKCiota signaling reveals that PKCiota is dispensable for adherent growth of non-small cell lung cancer cells but is required for transformed growth in soft agar in vitro and for tumorigenicity in vivo. Molecular dissection of signaling down-stream of PKCiota demonstrates that Rac1 is a critical molecular target for PKCiota-dependent transformation, whereas PKCiota is not necessary for NFkappaB activation in vitro or in vivo. Expression of the PB1 domain of PKCiota (PKCiota-(1-113)) blocks PKCiota-dependent Rac1 activity and inhibits cellular transformation indicating a role for this domain in the transforming activity of PKCiota. Taken together, our data demonstrate that PKCiota is a critical lung cancer gene that activates a Rac1-->Pak-->Mek1,2-->Erk1,2 signaling pathway required for transformed growth. Our data indicate that PKCiota may be an attractive molecular target for mechanism-based therapies for treatment of lung cancer.     

Effects of prostaglandin E2 (PGE2) on estradiol-17β-induced luteolysis in the nonpregnant ewe

Fifteen ewes were assigned as they came into estrus to the following randomized treatment groups: 1) Vehicle (1 ml corn oil + vehicle Na₂CO₃ buffer), 2) Estradiol-17β + vehicle and 3) Estradiol-17β + PGE₂ (500 μg) in Na₂CO₃ buffer (5 ewes/treatment group). Prostaglandin E₂ was given through an intrauterine cannula every four hours from days 8 through 15 postestrus. PGE₂ prevented a luteolytic dose of estradiol-17β given on days 9 and 10 from causing a precious luteolysis. PGE₂ maintained concentrations of progesterone in peripheral blood (days 8 through 15) and weights and concentrations of progesterone in corpora lutea on day 15 postestrus of ewes receiving estradiol-17β. It is concluded that chronic intrauterine infusions of PGE₂ can prevent an estradiol-17β-induced premature luteolysis.     

Prostaglandins F in uterine and ovarian venous plasma from nonpregnant and pregnant ewes collected by cannulation

Periodic collections of uterine venous blood were obtained from three nonmated, three pregnant and two mated but nonpregnant ewes in which uterine veins were cannulated with polyvinyl tubing on day 11 postestrus. Frequent sampling was achieved in three of these ewes with additional cannulae in the ovarian veins. Blood samples were collected at 3-hr intervals from 0600 on day 12 to 1800 on day 13 and then at 6-hr intervals through day 15. On day 13, three additional samples at 30-min intervals were collected between 1400 and 1530. Prostaglandins F (PGF) in plasma were quantified by radioimmunoassay.     

Mechanism whereby nitric oxide (NO) infused chronically intrauterine in ewes is antiluteolytic rather than being luteolytic

Nitric oxide (NO) has been reported to be luteolytic in vitro and in vivo in cows. However, an NO donor reversed PGF2alpha-induced inhibition of rat luteal progesterone secretion in vitro and an NO donor or endothelin-1 stimulated bovine luteal tissue secretion of prostaglandins E (PGE; PGE1, PGE2) in vitro without affecting progesterone or PGF2alpha secretion. In addition, chronic infusion of an NO donor into the interstitial tissue of the ovarian vascular pedicle adjacent the luteal-containing ovary prevented the decline in circulating progesterone, while a nitric oxide synthase (NOS) inhibitor did not affect luteolysis. The objective of this experiment was to determine whether an NO donor or NOS inhibitor infused chronically intrauterine adjacent to the luteal-containing ovary during the ovine estrous cycle was luteolytic or antiluteolytic. Ewes were treated either with vehicle (N=5), diethylenetriamine (DETA-control for DETANONOate; N=5), (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETANONOate-long acting NO donor; N=6), l-arginine (N=5), l-nitro-arginine methyl ester (l-NAME-NOS inhibitor; N=6), or NG-monomethyl-l-arginine acetate (l-NMMA; NOS inhibitor; N=5) every 6h from 2400h (0h) on day 8 through 1800h on day 18 of the estrous cycle. Jugular venous blood and inferior vena cava plasma via a saphenous vein cathether 5cm anterior to the juncture of the ovarian vein and inferior vena cava were collected every 6h for analysis for progesterone and PGF2alpha and PGE, respectively, by RIA. Corpora lutea were collected at 1800h on day 18 and weighed. Weights of corpora lutea were heavier (P< or =0.05) in DETANONOate-treated ewes when compared to vehicle, DETA, l-arginine, l-NAME, or l-NMMA-treated ewes, l-arginine luteal weights were heavier than vehicle, DETA, l-arginine, l-NAME, or l-NMMA-treated ewes, and luteal weights of vehicle, DETA, l-NAME, or l-NMMA-treated ewes did not differ amongst each other (P> or =0.05). Profiles of progesterone in jugular venous blood on days 8-18 differed (P< or =0.05) in DETANONOate-treated ewes when compared to vehicle, DETA, l-arginine, l-NMMA or l-NAME-treated ewes, which did not differ (P> or =0.05) amongst each other. The PGE:PGF2alpha ratio profile in inferior vena cava plasma of DETANONOate-treated ewes was increased (P< or =0.05) when compared to all other treatment groups. In a second experiment, conversion of [3H PGE2] to [3H PGF2alpha] by day 15 ovine caruncular endometrium in vitro was determined in vehicle, DETA, or DETANONOate-treatment groups. Conversion of [3H PGE2] to [3H PGF2alpha] was decreased (P< or =0.05) only by DETANONOate. It is concluded that NO is not luteolytic during the ovine estrous cycle, but may instead be antiluteolytic and prevent luteolysis by altering the PGE:PGF2alpha ratio secreted by the uterus.     

Trypanosome Alternative Oxidase Possesses both an N-Terminal and Internal Mitochondrial Targeting Signal

Recognition of mitochondrial targeting signals (MTS) by receptor translocases of outer and inner membranes of mitochondria is one of the prerequisites for import of nucleus-encoded proteins into this organelle. The MTS for a majority of trypanosomatid mitochondrial proteins have not been well defined. Here we analyzed the targeting signal for trypanosome alternative oxidase (TAO), which functions as the sole terminal oxidase in the infective form of Trypanosoma brucei. Deleting the first 10 of 24 amino acids predicted to be the classical N-terminal MTS of TAO did not affect its import into mitochondria in vitro. Furthermore, ectopically expressed TAO was targeted to mitochondria in both forms of the parasite even after deletion of first 40 amino acid residues. However, deletion of more than 20 amino acid residues from the N terminus reduced the efficiency of import. These data suggest that besides an N-terminal MTS, TAO possesses an internal mitochondrial targeting signal. In addition, both the N-terminal MTS and the mature TAO protein were able to target a cytosolic protein, dihydrofolate reductase (DHFR), to a T. brucei mitochondrion. Further analysis identified a cryptic internal MTS of TAO, located within amino acid residues 115 to 146, which was fully capable of targeting DHFR to mitochondria. The internal signal was more efficient than the N-terminal MTS for import of this heterologous protein. Together, these results show that TAO possesses a cleavable N-terminal MTS as well as an internal MTS and that these signals act together for efficient import of TAO into mitochondria.     

南方4种草本植物对铝胁迫生理响应的研究

 不同的植物对铝胁迫的生理响应不同, 因而对铝毒的耐性也不相同。设置5种铝浓度,进行砂培法处理,研究了4种我国南方红壤广泛分布的草本植物——牵牛(Pharbitis nil)、望江南(Cassia occidentlis)、光头稗(Echinochloa colonum)和合萌(Aeschynomene indica)的种子萌发、光合色素、脯氨酸含量、丙二醛(MDA)含量、可溶性糖(SS)含量、质膜透性(MP)、过氧化氢酶 (CAT) 活性以及过氧化物酶 (POD)活性的变化。结果表明铝对4种植物的生理特性都有明显的影响。4种植物的种子在10 000 mg·L－1 Al3+处理条件下都不能萌发。2 000 mg·L－1 Al3+处理都不利于4种植物的生长,与对照相比,2 000 mg·L－1 Al3+处理时4种草本植物叶绿素和叶绿素总含量显著降低(p<0.05);MDA含量和MP显著增加(p<0.05);脯氨酸含量极显著增加(p<0.01);POD和CAT活性极显著降低(p<0.01)。中低铝(80和400 mg·L－1)处理时,牵牛和合萌与对照相比,MP和MDA含量降低,POD和CAT活性升高;望江南的反应与牵牛和合萌的反应相反;光头稗在80 mg·L－1 Al3+处理时,与牵牛和合萌的变化一致,在400 mg·L－1 Al3+处理时,则相反。植物在中低铝处理条件下,通过维持较高的POD和CAT活性和脯氨酸、叶绿素含量,较低的MP和MDA含量来增加其对铝的耐性。     

Effects of prostaglandin E2 (PGE2) on estradiol-17 beta-induced luteolysis in the nonpregnant ewe

Fifteen ewes were assigned as they came into estrus to the following randomized treatment groups: 1) Vehicle (1 ml corn oil + vehicle Na2CO3 buffer), 2) Estradiol-17 beta + vehicle and 3) Estradiol-17 beta + PGE2 (500 micrograms) in Na2CO3 buffer (5 ewes/treatment group). Prostaglandin E2 was given through an intrauterine cannula every four hours from days 8 through 15 postestrus. PGE2 prevented a luteolytic dose of estradiol-17 beta given on days 9 and 10 from causing a precocious luteolysis. PGE2 maintained concentrations of progesterone in peripheral blood (days 8 through 15) and weights and concentrations of progesterone in corpora lutea on day 15 postestrus of ewes receiving estradiol-17 beta. It is concluded that chronic intrauterine infusions of PGE2 can prevent an estradiol-17 beta-induced premature luteolysis.     

Stereoselective formation and hydration of 12-methylbenz[a]anthracene 5,6-epoxide enantiomers by rat liver microsomal enzymes.

The K-region trans-5,6-dihydrodiols formed in the metabolism of 12-methylbenz[a]anthracene (12-MBA) by liver microsomal preparations from untreated, phenobarbital-treated and 3-methylcholanthrene-treated male Sprague-Dawley rats were found by chiral stationary-phase h.p.l.c. (c.s.p.-h.p.l.c.) analyses to contain (5S,6S)/(5R,6R) enantiomer ratios of 93:7, 88:12 and 97:3 respectively. The absolute stereochemistry of a 12-MBA trans-5,6-dihydrodiol enantiomer was elucidated by the exciton-chirality c.d. method. The 5,6-epoxides formed in the metabolism of 12-MBA by liver microsomal preparations from untreated, phenobarbital-treated and 3-methylcholanthrene-treated male Sprague-Dawley rats in the presence of the epoxide hydrolase inhibitor 3,3,3-trichloropropylene 1,2-oxide were isolated from a mixture of metabolites by normal-phase h.p.l.c., and their (5S,6R)/(5R,6S) enantiomer ratios were found by c.s.p.-h.p.l.c. analyses to be 73:27, 78:22 and 99:1 respectively. The absolute configurations of 12-MBA 5,6-epoxide enantiomers, resolved by c.s.p.-h.p.l.c., were determined via high-resolution (500 MHz) proton-n.m.r. and c.d. spectral analyses of the two isomeric methoxylation products derived from each of the 12-MBA 5,6-epoxide enantiomers. Enantiomeric pairs of the two methoxylation products were resolved by c.s.p.-h.p.l.c. The results indicate that enantiomeric 5S,6R-epoxide and 5S,6S-dihydrodiol were the major enantiomers preferentially formed in the metabolism at the K-region 5,6-double bond of 12-MBA by all three rat liver microsomal preparations. Optically pure 12-MBA 5S,6R-epoxide was hydrated predominantly at the C(6) position (R centre) to form 12-MBA trans-5,6-dihydrodiol with a (5S,6S)/(5R,6R) enantiomer ratio of 97:3. However, optically pure 12-MBA 5R,6S-epoxide was hydrated nearly equally at both C(5) and C(6) positions to form 12-MBA trans-5,6-dihydrodiol with a (5S,6S)/(5R,6R) enantiomer ratio of 57:43.