MACROPODID MARSUPIAL LUTEINIZING HORMONE: VALIDATION OF ASSAY PROCEDURES AND CHANGES IN CONCENTRATIONS IN PLASMA DURING THE OESTROUS CYCLE IN THE FEMALE TAMMAR WALLABY (MACROPUS EUGENII)

1980 ◽  
Vol 86 (1) ◽  
pp. 1-12 ◽  
Author(s):  
R. L. SUTHERLAND ◽  
SUSAN M. EVANS ◽  
C. H. TYNDALE-BISCOE
Keyword(s):  
Limit Of Detection ◽  
Tammar Wallaby ◽  
Response Curves ◽  
Macropus Eugenii ◽  
Wide Range ◽  
Marsupial Species ◽  
Lh Rh ◽  
Lh Releasing Hormone ◽  
Australian Marsupial ◽  
Serial Dilutions

A heterologous double antibody radioimmunoassay employing a rabbit anti-ovine LH antiserum (GDN no. 15) has been developed for the assessment of concentrations of LH in macropodid marsupial pituitary extracts and plasma. In this radioimmunoassay system highly purified ovine, rat, human and kangaroo LH preparations demonstrated apparently parallel dose–response curves, as did serial dilutions of crude pituitary extracts from a wide range of Australian marsupial species and serial dilutions of plasma from ovariectomized, oestrous and LH releasing hormone (LH-RH)-treated marsupials. The assay has been used to monitor changes in immunoreactive LH in the plasma of the female tammar wallaby. Basal concentrations of LH in non-oestrous female wallabies were in the range < 0·20–1·90 ng/ml with many animals having values at or near the limit of detection of the assay. Concentrations of LH were markedly increased following ovariectomy (1·7–7·0 ng/ml), on the day of oestrus (10·0–> 50 ng/ml) and following administration of LH-RH (9·5–> 25·0 ng/ml). Plasma from hypophysectomized animals had no detectable LH immunoactivity, A well-defined LH surge, lasting approximately 12 h, was associated with oestrus. Mating occurred approximately 8 h before, and ovulation approximately 24 h after, the maximal concentration of LH in plasma.

Mullerian inhibiting substance production and testicular migration and descent in the pouch young of a marsupial

Development ◽  
1988 ◽  
Vol 104 (4) ◽  
pp. 549-556 ◽  
Author(s):  
J.M. Hutson ◽  
G. Shaw ◽  
W.S. O ◽  
R.V. Short ◽  
M.B. Renfree
Keyword(s):  
Tammar Wallaby ◽  
Testicular Descent ◽  
Future Studies ◽  
Macropus Eugenii ◽  
Müllerian Inhibiting Substance ◽  
Sequence Of Events ◽  
Testicular Differentiation ◽  
Testicular Migration ◽  
Australian Marsupial ◽  
Mullerian Inhibiting Substance

The ontogeny of Mullerian inhibiting substance (MIS) production by the developing testis of an Australian marsupial, the tammar wallaby (Macropus eugenii), was determined during pouch life using an organ-culture bioassay of mouse fetal urogenital ridge. This information was related to the morphological events during testicular migration and descent. MIS biological activity was found in testes (but not ovaries or liver) of pouch young from 2 to 85 days of age. MIS production had commenced by day 2, which is within a day of the first gross morphological signs of testicular differentiation. Mullerian duct regression occurred between 10 and 30 days, which partly coincided with testicular migration to the inguinal region and enlargement of the gubernacular bulb (15 to 30 days). These observations are consistent with the hypothesis that MIS may be involved in testicular transabdominal migration. The epididymis commenced development and growth only after the testis had descended through the inguinal ring. This provides no support for the suggestion that the epididymis is involved in testicular descent into the scrotum. The basic sequence of events in post-testicular sexual differentiation in the wallaby is sufficiently similar to that seen in eutherian mammals to make it an excellent experimental model for future studies of testicular differentiation, migration and descent.

scholarly journals Pharmacodynamic Evaluation of the Intracellular Activity of Antibiotics towards Pseudomonas aeruginosa PAO1 in a Model of THP-1 Human Monocytes

2013 ◽  
Vol 57 (5) ◽  
pp. 2310-2318 ◽  
Author(s):  
Julien M. Buyck ◽  
Paul M. Tulkens ◽  
Françoise Van Bambeke
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Limit Of Detection ◽  
Phagocytic Cells ◽  
Response Curves ◽  
Content Type ◽  
Initial Inoculum ◽  
Wide Range ◽  
Pharmacodynamic Approach ◽  
Monocyte Infection ◽  
Intracellular Milieu

ABSTRACTPseudomonas aeruginosainvades epithelial and phagocytic cells, which may play an important role in the persistence of infection. We have developed a 24-h model of THP-1 monocyte infection withP. aeruginosaPAO1 in which bacteria are seen multiplying in vacuoles by electron microscopy. The model has been used to quantitatively assess antibiotic activity against intracellular and extracellular bacteria by using a pharmacodynamic approach (concentration-dependent experiments over a wide range of extracellular concentrations to calculate bacteriostatic concentrations [Cs] and maximal relative efficacies [Emax]; Hill-Langmuir equation). Using 16 antipseudomonal antibiotics (three aminoglycosides, nine β-lactams, three fluoroquinolones, and colistin), dose-response curves were found to be undistinguishable for antibiotics of the same pharmacological class if data were expressed as a function of the corresponding MICs. Extracellularly, all of the antibiotics reached a bacteriostatic effect at their MIC, and theirEmaxexceeded the limit of detection (−4.5 log10CFU compared to the initial inoculum). Intracellularly,Csvalues remained unchanged for β-lactams, fluoroquinolones, and colistin but were approximately 10 times higher for aminoglycosides, whereasEmaxvalues were markedly reduced (less negative), reaching −3 log10CFU for fluoroquinolones and only −1 to −1.5 log10CFU for all other antibiotics. The decrease in intracellular aminoglycoside potency (higherCs) can be ascribed to the acid pH to which bacteria are exposed in vacuoles. The decrease in theEmaxmay reflect a reversible alteration of bacterial responsiveness to antibiotics in the intracellular milieu. The model may prove useful for comparison of antipseudomonal antibiotics to reduce the risk of persistence or relapse of pseudomonal infections.

Low MHC class II variability in a marsupial

1994 ◽  
Vol 6 (6) ◽  
pp. 721 ◽  
Author(s):  
LM McKenzie ◽  
DW Cooper
Keyword(s):  
Genetic Variation ◽  
Mhc Class Ii ◽  
Fragment Length Polymorphism ◽  
Tammar Wallaby ◽  
Class Ii ◽  
Mixed Lymphocyte Culture ◽  
Lymphocyte Culture ◽  
Macropus Eugenii ◽  
Histocompatibility Complex ◽  
Marsupial Species

The major histocompatibility complex (MHC) loci have been shown to be highly polymorphic in most eutherian ('placental') species studied. Several hypotheses have been advanced for the maintenance of this exceptional level of genetic variation, one of which suggests that it is necessary for successful eutherian reproduction. Marsupials (metatherians) and eutherians are the only two groups of viviparous mammals, but their modes of reproduction are quite distinct. Although marsupials have placentae, they are generally shorter lived and less invasive than in eutherians. Other investigations have shown that genetic variation at marsupial MHC class I loci is probably high. Weak or non-existent mixed lymphocyte culture responses previously reported in several marsupial species have suggested a lack of class II variation. Data have therefore been collected on the level of restriction fragment length polymorphism at MHC class II beta-chain encoding loci of a marsupial, Macropus eugenii (the tammar wallaby). This level is shown to be low, between the level of MHC variation found in cheetahs and a population of lions with a restricted genetic base. Attention is drawn to the need to collect more data on the level of class II variability in both eutherians and marsupials, and to the potential of marsupials for understanding the relation, if any, between mode of reproduction and MHC variability.

scholarly journals Induction of sperm maturation in vitro in epididymal cell cultures of the tammar wallaby (Macropus eugenii): disruption of motility initiation and sperm morphogenesis by inhibition of actin polymerization

Reproduction ◽  
2002 ◽  
pp. 107-117 ◽  
Author(s):  
M Lin ◽  
R Hess ◽  
RJ Aitken
Keyword(s):  
Culture System ◽  
Actin Polymerization ◽  
Tammar Wallaby ◽  
Sperm Maturation ◽  
Actin Organization ◽  
Cell Monolayers ◽  
Macropus Eugenii ◽  
Maturation In Vitro ◽  
Marsupial Species

A sperm-epididymal cell co-culture was shown to be capable of inducing the in vitro maturation of spermatozoa from a marsupial species, the tammar wallaby (Macropus eugenii). This system was able to maintain wallaby epididymal epithelial cells in vitro for more than 2 months. The system also enabled immature wallaby spermatozoa to differentiate from a T-shaped to a streamlined form, accompanied by the development of progressive motility after co-culture with epididymal cell monolayers that had been cultured for 7 days. The addition of inhibitors of actin polymerization (latrunculin A or B) to the co-culture system showed that wallaby sperm maturation was impaired by the interruption of actin organization within the immature spermatozoa. These results indicate that actin filaments play a significant role in sperm transformation during post-testicular maturation in marsupials. These observations also indicate that the marsupial co-culture system has the potential to greatly increase understanding of sperm-epididymal cell interactions and the mechanism of sperm maturation in these species.

RESPONSE OF LUTEINIZING HORMONE FROM COLUMNS OF DISPERSED RAT PITUITARY CELLS TO A HIGHLY POTENT ANALOGUE OF LUTEINIZING HORMONE RELEASING HORMONE

1981 ◽  
Vol 91 (1) ◽  
pp. 33-41 ◽  
Author(s):  
T. YEO ◽  
A. GROSSMAN ◽  
P. BELCHETZ ◽  
G. M. BESSER
Keyword(s):  
Luteinizing Hormone ◽  
Single Pulse ◽  
Pituitary Cells ◽  
Response Curves ◽  
Releasing Hormone ◽  
Rat Pituitary ◽  
Constant Dose ◽  
Rat Pituitary Cells ◽  
Lh Rh ◽  
Lh Releasing Hormone

The response of LH from a perfused column of dispersed rat anterior pituitary cells to LH releasing hormone (LH-RH) and the analogue, d-Ser(But)6-desGly10-Proethylamide9-LH-RH (Hoe 766), was investigated. Dose–response curves showed non-parallelism between LH-RH and the analogue, but it was evident that the analogue was considerably more potent. After a single pulse of LH-RH, LH output returned to basal values in 8 min; this was prolonged to 20 min in the case of the analogue. During this 20 min the cells were refractory to pulses of LH-RH but pulses of the analogue maintained output of LH. During constant-dose perfusion with either synthetic LH-RH or the analogue, output of LH rapidly reached a peak and then gradually fell over several hours to approach baseline values. However, a pulse of 50 mmol potassium chloride/l was still able to release LH at this time. The data are consistent with the view that this analogue of LH-RH is highly potent and is strongly bound by the LH-RH receptor. Furthermore, since it desensitizes the LH-RH receptor, it appears that continued turnover of either LH-RH or the analogue at the receptor is necessary for output of LH to be maintained.

scholarly journals Ancient Viral Integrations in Marsupials: A Potential Antiviral Defence

2021 ◽  
Author(s):  
Emma F Harding ◽  
Alice G Russo ◽  
Grace J H Yan ◽  
Paul D Waters ◽  
Peter A White
Keyword(s):  
Viral Infections ◽  
Active Role ◽  
Tammar Wallaby ◽  
Eutherian Mammal ◽  
Brushtail Possum ◽  
Replicase Gene ◽  
Tasmanian Devil ◽  
Available N ◽  
Marsupial Species ◽  
Australian Marsupial

Abstract Marsupial viruses are understudied compared to their eutherian mammal counterparts, although they may pose severe threats to vulnerable marsupial populations. Genomic viral integrations, termed endogenous viral elements (EVEs) could protect the host from infection. It is widely known past viral infections and EVEs play an active role in antiviral defence in invertebrates and plants. This study aimed to characterise actively transcribed EVEs in Australian marsupial species, because they may play an integral role in cellular defence against viruses. This study screened publicly available RNA sequencing datasets (n=35) and characterised 200 viral transcripts from thirteen Australian marsupial species. Of the 200 transcripts, 188 originated from either Bornaviridae, Filoviridae or Parvoviridae EVEs. The other 12 transcripts were from putative active infections from members of the Herpesviridae and Anelloviridae, and Hepadnaviridae. EVE transcripts (n=188) were mapped to marsupial genomes (where available, n=5/13) to identify the genomic insertion sites. Of the 188 transcripts, 117 mapped to 39 EVEs within the koala, bare-nosed wombat, tammar wallaby, brushtail possum and Tasmanian devil genomes. The remaining eight animals had no available genome (transcripts n=71). Every marsupial have Bornaviridae, Filoviridae and Parvoviridae EVEs, a trend widely observed in eutherian mammals. Whilst eutherian bornavirus EVEs are predominantly nucleoprotein-derived, marsupial bornavirus EVEs demonstrate a surprising replicase gene bias. We predicted these widely distributed EVEs were conserved within marsupials from ancient germline integrations, as many were over 65 million years old. One bornavirus replicase EVE, present in six marsupial genomes, was estimated to be 160 million years old, predating the American-Australian marsupial split. We considered transcription of these EVEs through small non-coding RNA as an ancient viral defence. Consistent with this, in koala small RNA sequence datasets we detected Bornaviridae replicase and Filoviridae nucleoprotein produced piRNA. These were enriched in testis tissue, suggesting they could protect marsupials from vertically transmitted viral integrations.

THE INFLUENCE OF TIME, DOSE AND GONADAL STEROIDS ON LH-RH-INDUCED GONADOTROPHIN RELEASE IN RATS

1975 ◽  
Vol 78 (4) ◽  
pp. 695-704 ◽  
Author(s):  
Wolfgang Lotz
Keyword(s):  
Time Course ◽  
Time Lapse ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Response Curves ◽  
Intact Male ◽  
Maximal Increase ◽  
Serum Lh ◽  
Lh Rh ◽  
Lh Releasing Hormone

ABSTRACT Hypophyseal responses to LH-releasing hormone (LH-RH) were studied in ovariectomized rats, pre-treated once with 50 μg oestradiol-3-benzoate alone or in combination with 25 mg progesterone either 16, 24, 48 or 72 h before the administration of LH-RH. The highest serum gonadotrophin increase was detected in ovariectomized rats pre-treated with oestrogen 48 h before the LH-RH injection. The serum LH concentration change in intact male rats was markedly lower in terms of order of magnitude than in ovariectomized, oestradiol-3-benzoate, progesterone-treated rats ("O. Oe. P."-rats). These latter test animals showed the maximal increase of serum LH concentration, depending on the dose of LH-RH, after 10 to 25 min and that of FSH after 40 min. The dose-response curves for LH release in "O. Oe. P."-rats were linear for short (10 and 15 min) and sigmoid for longer time intervals (20, 30 and 40 min) between LH-RH injection and sacrifice. The possible reasons for the difference in both magnitude and time-lapse for maximal increase of serum LH and FSH concentration, the influence of steroid pre-treatment and the variation of the time-course of serum LH concentration, depending on the dose of LH-RH, are discussed.

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