Rapid Communication: 16S ribosomal ribonucleic acid characterization of liver abscesses in feedlot cattle from three states in the United States.

Liver abscesses are a major economic burden to beef producers. Although a few causative organisms have been cultured from purulent material, the full polymicrobial diversity of liver abscesses has not been reported. The objective of this study was to characterize purulent material collected from liver abscess in beef cattle produced in different production systems in 3 cattle producing states in the United States using 16S rRNA gene sequencing. Differences between purulent material microbial communities among geographic region of feeding and application of a common antimicrobial were also investigated. Cattle included in the study were fed in California (dairy type) and Colorado and Texas (both beef type). Liver abscesses from a cross section of feedlots, geographic areas, and tylosin phosphate-administered groups were collected at harvest; DNA from 34 liver abscess samples was extracted; and the V4 region of the 16S rRNA gene was amplified and sequenced. Sequences were classified into 5 phyla, 13 classes, and 17 orders in the domain Bacteria. The phyla identified included Bacteroidetes (35.2% of reads), Proteobacteria (28.6%), Fusobacteria (18.2%), Firmicutes (12.4%), and Actinobacteria (5.5%). Sequences matching the genera and , which have previously been identified as causative agents in liver abscesses, were both present in the abscess bacterial communities at a relative abundance of 15.1 and 3.2%, respectively, of the overall relative abundance. Furthermore, 3 of the most common phyla were Gram-negative bacteria. An analysis-of-similarities test was conducted on Euclidean distances to assess differences between cattle treated and not treated with tylosin as well as to assess differences between geographic regions. Geographical region and treatment with tylosin did affect the microbiome ( = 0.002 and = 0.026 respectively); however, a more robust sample scheme is needed to explore these differences. To our knowledge, this is the first publication describing the complex community of liver purulent material using next generation sequencing in cattle. These data provide a framework for research on a more targeted approach to liver abscess prevention and treatment.

K63-ubiquitylation of VHL by SOCS1 mediates DNA double-strand break repair.

DNA repair is essential for maintaining genomic stability, and defects in this process significantly increase the risk of cancer. Clear-cell renal cell carcinoma (CCRCC) caused by inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is characterized by high genomic instability. However, the molecular mechanism underlying the association between the loss of VHL and genomic instability remains unclear. Here, we show that suppressor of cytokine signaling 1 (SOCS1) promotes nuclear redistribution and K63-ubiquitylation of VHL in response to DNA double-strand breaks (DSBs). Loss of VHL or VHL mutations that compromise its K63-ubiquitylation attenuates the DNA-damage response (DDR), resulting in decreased homologous recombination repair and persistence of DSBs. These results identify VHL as a component of the DDR network, inactivation of which contributes to the genomic instability associated with CCRCC.

Historical stocking data and 19th century DNA reveal human-induced changes to native diversity and distribution of cutthroat trout.

Many species are threatened with extinction and efforts are underway worldwide to restore imperilled species to their native ranges. Restoration requires knowledge of species' historical diversity and distribution. For some species, many populations were extirpated or individuals moved beyond their native range before native diversity and distribution were documented, resulting in a lack of accurate information for establishing restoration goals. Moreover, traditional taxonomic assessments often failed to accurately capture phylogenetic diversity. We illustrate a general approach for estimating regional native diversity and distribution for cutthroat trout in the Southern Rocky Mountains. We assembled a large archive of historical records documenting human-mediated change in the distribution of cutthroat trout (Oncorhynchus clarkii) and combined these data with phylogenetic analysis of 19th century samples from museums collected prior to trout stocking activities and contemporary DNA samples. Our study of the trout in the Southern Rocky Mountains uncovered six divergent lineages, two of which went extinct, probably in the early 20th century. A third lineage, previously declared extinct, was discovered surviving in a single stream outside of its native range. Comparison of the historical and modern distributions with stocking records revealed that the current distribution of trout largely reflects intensive stocking early in the late 19th and early 20th century from two phylogenetically and geographically distinct sources. Our documentation of recent extinctions, undescribed lineages, errors in taxonomy and dramatic range changes induced by human movement of fish underscores the importance of the historical record when developing and implementing conservation plans for threatened and endangered species.

Methoxychlor mimics the action of 17 beta-estradiol on induction of uterine epidermal growth factor receptors in immature female rats.

Epidermal growth factor (EGF) and its receptor (EGF-R) have been implicated as mediators for estrogen induced cellular growth. This study examines whether the action of the estrogenic pesticide methoxychlor (MXC) parallels the action of 17 beta-estradiol (E2) on uterine EGF-R. Administration of 20 micrograms E2/sexually immature female rat increased 125I-EGF binding to membranes extracted from whole uteri 175% over endogenous levels, while 500 mg MXC/kg led to a 156% increase. E2 in both 20 and 40 micrograms/rat doses and 500 mg MXC/kg led to maximal stimulation over endogenous levels, 12-h posttreatment. Rats were treated with E2, MXC, or vehicle plus 100 micrograms actinomycin-D (ACT-D) or 100 micrograms cycloheximide (CYCLO) per rat to determine if mRNA transcription and translation are involved in the increased EGF-R binding following estrogenic treatment. Only ACT-D inhibited the estrogenic stimulation of EGF-R binding, resulting in a 44% decrease when given concurrently with E2 or MXC, suggesting transcription is required. Additionally, ACT-D decreased endogenous receptor levels by 55%. No other differences were detected. When EGF-R binding data were analyzed by the method of Scatchard, both E2 and MXC, at maximal dosages, elevated uterine EGF-R binding sites by over 200% after 12 h as measured by maximal binding (Bmax) with no significant difference in dissociation constant (Kd) values. These results demonstrate that both E2 and MXC can stimulate the number of EGF-R binding sites without significantly altering the receptor binding affinity (Kd). Further, this stimulation is time dependent and is affected by dose.

Effect of surgically induced endometriosis on pregnancy and effect of pregnancy and lactation on endometriosis in mice.

Endometriosis, a disease of women and nonhuman primates in which endometrial tissue grows outside the uterus, can be mimicked surgically in rats and mice. The disease is related to infertility in women, and surgical induction of endometriotic lesions reduces fertility in rats according to some studies. Conversely, pregnancy appears to have a beneficial effect on endometriosis in women and some rat studies. Our objective was to evaluate a new mouse model of surgically induced endometriosis with respect to the effects of pregnancy on endometriosis and the effects of endometriosis on pregnancy. Female B6C3F1 mice were divided into four groups. Those in Group A and B underwent induction surgery for endometriosis and hemi-ovariectomy, those in Group C underwent sham surgery and hemi-ovariectomy, and animals in Group D received no surgery at all. Three weeks later, Group A, C, and D were bred. Eighteen days later one half of the dams in Groups A, B, and C only were sacrificed, and evaluations included endometriotic lesion diameter, number of pups, fetal weight, and various organ weights. The remaining dams delivered, and, 18 days after parturition, dams and pups were sacrificed. Evaluations included gestation length and those listed above. Endometriotic lesion diameter was significantly reduced in pregnant animals when compared with nonpregnant controls, but the reduction was not a full regression. Lactation returned the mean lesion diameter to pre-pregnancy dimensions. When effects of endometriosis on pregnancy were evaluated, no effects on the litter size, pup weight, or gestation length were found, but trends toward increased resorptions and malformations were evident. Thus, in the mouse model of induced endometriosis, pregnancy produced a significant reduction in endometriotic lesion diameter while fertility was largely unaffected by the surgically induced endometriosis. The mouse model of endometriosis thus appears more resistant than the rat model to effects of endometriosis on fertility.

Promotion of endometriosis by 2,3,7,8-tetrachlorodibenzo-p-dioxin in rats and mice: time-dose dependence and species comparison.

In the disease of endometriosis, endometrial tissue grows outside the uterus, usually in the peritoneal cavity. Rodent models of endometriosis allow a way to reproduce the disease, evaluate effects of chemicals, and study mechanisms. Twenty-one days prior to induction surgery which produces endometriosis, female Sprague-Dawley rats and B6C3F1 mice were pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at 0, 3 or 10 micrograms TCDD/kg. Animals were treated again at the time of surgery and at 3, 6, and 9 weeks following surgery. Evaluations were made at 3, 6, 9, and 12 weeks postsurgery. TCDD produced a dose-dependent increase in endometriotic site diameter when all time points were pooled within each dose in rats and a dramatic increase in site diameter in mice at 9 and 12 weeks. In rats but not mice, ovarian weight was decreased at 9 and 12 weeks, the occurrence of persistent vaginal estrus was increased at these times, and histological evaluation of the ovaries revealed ovulatory arrest at 12 weeks. In both species, thymic antrophy, indicating immune dysfunction, and hepatomegaly were observed as consequences of TCDD exposure. Body weight was reduced in rats but not in mice. Histological evaluations of endometriotic sites revealed fibrosis in control rats, necrotic and inflammatory changes in the sites from TCDD-treated rats, and predominantly fibrotic changes in sites from TCDD-treated mice. Differences observed between the rat and the mouse with respect to (a) the magnitude of the effect on endometrial site diameter (rats < mice), (b) measured effects on ovarian function (rats > mice) that may be based on the partial antiestrogenicity of TCDD, and (c) evidence that mice and rats differ in their immune response to TCDD suggest that the mechanisms mediating TCDD's action to promote endometriosis are complex and may be different in rats and mice. The mouse may be a better model for future studies necessary to elucidate these mechanisms.

Effects of estrogen, progesterone, and methoxychlor on surgically induced endometriosis in rats.

Endometriosis is a disease of women where endometrial tissue is found growing at ectopic sites. While evidence suggesting a role for the ovarian hormones in endometriosis exists, no complete studies of the roles of estrogen and progesterone have heretofore been performed. Also, if estrogen has a role in the growth and/or maintenance of endometriosis, it is likely that the proestrogenic pesticide, methoxychlor (MXC), might also have such an effect. Sixty rats underwent surgery on Day 0 to induce endometriosis. On Day 21, all rats were ovariectomized. During surgery, the diameters of all endometriotic implants (which were fully developed) were measured. Starting on Day 21, groups of rats were treated daily, for 3 weeks, with (a) vehicle (b) estrone, 1 micrograms/rat, E;(c) progesterone, 2 mg/rat, P; (d) E + P, 1 micrograms + 2 mg; (e) MXC, 250 mg/kg; or (f) MXC + P, 250 mg/kg + 2 mg/rat. On Day 42, all rats were killed, and the diameters of all endometriotic sites were measured. While no differences in diameter were found across groups prior to ovariectomy, ovariectomy plus treatment altered the growth of endometriosis tissue. Progesterone and vehicle treatments produced results that were identical: regression of endometriotic sites. Both estrogen and MXC treatments maintained endometriotic site size at a level greater than that in the vehicle-treated group. The combination of progesterone with either estrone or MXC did not alter the effect of either chemical. We conclude that while estrogen promotes the growth of endometriosis, progesterone either produces regression or fails to maintain the sites. MXC, at a relatively high dose, supports the development of endometriosis. Concurrent progesterone treatment does not modulate the effects of estrone or MXC. These results suggest that exposure of women to high doses of MXC may exacerbate the development of endometriosis or contribute to its recurrence.

Induction of endometriosis in mice: a new model sensitive to estrogen.

Endometriosis consists of the growth of endometrial tissue outside the uterus. A rat model of endometriosis is available to evaluate the potential for environmental chemicals to promote the disease but may be relatively insensitive for the evaluation of the hazard of certain compounds. Our objective, which was to develop a mouse model for endometriosis, was based on (a) the promotion of endometriosis in primates by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), (b) the apparent relationship between endometriosis and immunodeficiency, and (c) evidence that humoral immunity is suppressed in mice but not rats following TCDD exposure. In the mouse model, slices of uterus were sutured to intestinal mesenteric vessels. By 3 weeks after surgery, these sites were cyst-like structures. The growth of the sites was hormone dependent. In intact mice, sites measured 3.60 +/- 0.22 mm; vehicle and estrone (0.5 microgram/day) treatments produced site diameters of 0.95 +/- 0.128 and 5.28 +/- 0.355 mm, respectively. This new mouse model provides a sensitive and useful technique for future studies of the potential for specific xenobiotics to promote the development of endometriosis.

Methoxychlor regulates rat uterine estrogen-induced protein.

Methoxychlor (MXC), a proestrogenic pesticide, has adverse effects on fertility and uterine function in rodents. MXC is converted to an estrogenic substance, 2,2-bis-(p-hydroxyphenyl)-1,1,1-trichloroethane (HPTE), which binds to the estrogen receptor. We examined the similarities in mechanism between MXC (500 mg/kg) and estrogen (10 micrograms/rat) actions using the estrogen-induced protein, IP, also known as creatine kinase. Immature, female rats were treated with MXC or estradiol (E2). Concurrent treatment included actinomycin D (100 micrograms), cycloheximide (100 micrograms), or progesterone (0.5 mg). Uterine proteins were labeled in vitro with 3H for treated rats and with 14C for controls. The uteri were combined, cytosol was isolated, non-denaturing (ND) gels were run, and dpm/gel slice were plotted. In a follow-up study, labeled cytosols from MXC- and E2-treated rats were immunoprecipitated with a monoclonal antibody to creatine kinase. The immunoprecipitate was run on SDS gels. The data show that both MXC and E2 treatments result in ND gels with peaks in (a) induced protein and (b) the 3H/14C ratio, in the same position. The induction of IP by MXC is time- and dose-dependent. Concurrent treatment with MXC plus actinomycin D or cycloheximide blocked IP synthesis, a result parallel to E2 action signifying the necessity of RNA and protein synthesis for IP induction. Progesterone did not block either MXC or E2 induction of IP synthesis. Immunoprecipitation of creatine kinase revealed a single peak at a molecular weight of approximately 49,000. SDS gels of cytosol after MXC or E2 treatment also yielded protein and ratio peaks at molecular weights of approximately 49,000. This estimate is near the published estimated molecular weight of creatine kinase of 46,000. We conclude that MXC action parallels that of estradiol on the induction and regulation of the estrogen-induced protein in immature rat uterus.

Mechanisms of the stimulation of rat uterine peroxidase activity by methoxychlor.

Methoxychlor (MXC) has adverse effects on fertility and rat uteri via its active metabolite HPTE (2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane). Uterine peroxidase, a marker of estrogen action, was used to probe potential mechanisms of MXC's adverse effects. Specifically, our objective was to compare the regulation of the effects of estrogen and MXC on uterine peroxidase. Immature female rats were treated with MXC (250 mg/kg; gavage) 24 h prior to the measurement of uterine peroxidase activity, with or without concurrent treatment with actinomycin D, cycloheximide, progesterone, or tamoxifen. MXC alone produced an increase in peroxidase activity. The prior and/or concurrent treatment with the compounds listed blocked the MXC-induced stimulation of peroxidase. These data show similarities between the mechanisms of estrogen MXC action. Both estrogen and MXC act to stimulate uterine peroxidase activity via increased RNA and protein synthesis and this stimulation can be blocked by progesterone and tamoxifen.

Parametric analysis of elasto-optic birefringent axis alignment in eccentrically coated polarization-maintaining optical fiber.

When high-birefringent fibers are used in polarization-sensitive devices, one must ensure the proper alignment of the optical axes. One nondestructive alignment method involves squeezing the fiber and noting the change in the resultant birefringent axes. We use the finite-element method to determine the change in the principal stress direction, and, hence, the extrinsic birefringent axis orientation, as a function of the fiber coating eccentricity. Fiber eccentricity can shift the extrinsic birefringent axis by more than 1.5 degrees , whch becomes important in high-performance device applications.