bluuebunny/crossref_metadata_2025 huggingface dataset:
Carotenoids and Photosystem II Characteristics of Upper and Lower Halves of Leaves Acclimated to High Light
Authors: Adams WW Iii , Demmig-Adams B , Barker DH , Kiley S
Published: January 2006

Acclimation of the leaves or stems of four succulent species to different light environments and to the light gradient across high light-acclimated tissues was examined through measurements of chlorophyll fluorescence and characterisation of the pigment composition of the thylakoid membranes. Whereas the total amounts of light striking the upper (sun-exposed) and lower (self-shaded) surfaces were quite different, resulting in a much smaller pool of the xanthophyll cycle carotenoids in the lower halves of high light-acclimated tissues, the conversion state of the xanthophyll cycle (the degree to which violaxanthin is converted to antheraxanthin and zeaxanthin) was similar throughout the tissues during exposure to natural sunlight. Under full sunlight, less than 25% of the light absorbed by the upper surface was utilised through photosynthesis, with the majority of the remaining excitation energy being dissipated thermally. In contrast, a considerably greater fraction of the light absorbed by the lower surface was utilised in photosynthesis, ranging from one-third to more than two-thirds of the total energy absorbed.
Transformation of an Australian Variety of Carica papaya Using Microprojectile Bombardment
Authors: Mahon RE , Bateson MF , Chamberlain DA , Higgins CM , Drew RA , Dale JL
Published: January 2006

We have developed a method for the stable transformation and regeneration of a dioecious Australian cultivar of Carica papaya (papaw or papaya) by microprojectile bombardment. This method was developed after investigation of both zygotic and somatic embryos as target tissue and optimisation of a number of parameters using transient expression of the uidA reporter gene. The tissue culture regime prior to bombardment was critical in optimisation of transformation. Factors such as age of embryos and various treatments prior to bombardment, increased transient expression by up to 22-fold. Highest uidA transient expression results were obtained when somatic embryos 3 weeks since last subculture on solid medium were given a 3 day treatment in liquid medium, and a 2 h osmotic treatment pre- and post-bombardment. Stably transformed plants were obtained 6 months after bombardment using this system. Transformation efficiency was high with two experiments yielding 45% and 37.5% of bombarded plates regenerating plantlets on media containing kanamycin. The presence of both the uidA and aphA genes, (selectable marker) which code for the enzymes β-glucuronidase (GUS), and neomycin phosphotransferase II (NPTII) respectively, was confirmed in regenerated plantlets by Southern hybridisation.
The Cytoplasmic Streaming Response of Tomato Root Hairs to Auxin; the Role of Calcium
Authors: Ayling SM , Clarkson DT
Published: January 2006

The effects of IAA on the cytoplasmic streaming response of tomato root hairs were observed at different external calcium concentrations. The sensitivity of tomato root hairs to IAA was increased by increasing the calcium content of the bathing medium; lower concentrations of IAA were needed to stimulate cytoplasmic streaming at high [Ca2+]ext. The transplasma membrane electrical potential difference was rapidly depolarised by IAA across a wide range of auxin and calcium concentrations; subsequent hyperpolarisation was only seen in the presence of high [Ca2+]ext. Measurements of cytoplasmic calcium levels, using the dye fluo-3, revealed the dynamic nature of the cytoplasm. As in earlier experiments, in which indo-1 and fura-2 were used, IAA appeared to have only small effects on [Ca2+]cyt. Clear, auxin-induced changes in [Ca2+]cyt were recorded only under non-physiological conditions.
The Association of Biomass Allocation With Growth and Water Use Efficiency of Two Triticum aestivum Cultivars
Authors: Boogaard RVD , Veneklaas EJ , Lambers H
Published: January 2006

We investigated traits that might improve performance of wheat (Triticum aestivum L.) in a dry environment, and examined if the response to drought is different for cultivars with a contrasting biomass allocation pattern, using two cultivars with either a high (Katya) or small (Mexipak) proportion of biomass allocated to the leaves. Plants were grown in pots placed in the field, under well-watered conditions and under intermittent drought. Katya allocated a greater proportion of its biomass to both leaves and roots, and a smaller proportion to stems than Mexipak did. The growth rate of Katya was not higher despite a higher investment in leaf area and a slightly higher rate of photosynthesis, possibly due to concomitantly higher respiratory losses. Under well-watered conditions, the efficiency of water use for growth was higher for Katya than for Mexipak, due to a lower water use at a similar growth rate. Differences in water use per plant were determined by the rate of water loss or uptake, rather than by the amount of roots or leaves. A high water use efficiency was independent of growth rate. We conclude that a lower rate of water use due to a lower transpiration per unit leaf area linked with a high leaf area can contribute to improve the performance of wheat cultivars in a water-limited environment.
Increasing Night Temperature Can Reduce Seed Set and Potential Yield of Tropical Rice
Authors: Ziska LH , Manalo PA
Published: January 2006

The effect of increasing day temperature on reducing seed set in rice is well established, but little is known concerning the impact of increasing night temperature relative to constant day temperature. Recent work suggests that anticipated global warming may be uneven, with a significant increase in night compared to day temperature. Sun-lit, outdoor environment chambers were used to determine the impact of increasing night temperatures at two constant day temperatures (29/21, 29/25, 29/29�C and 33/25, 33/29 and 33/33�C) as well as increasing day/night temperature (29/21, 33/25 and 36/29�C) on growth and yield of rice (cv. IR 72). Increasing daylnight temperature to 36/29�C resulted in a significant reduction in both plant biomass and grain yield at harvest. At a constant day temperature of 29�C, increasing night temperature did not significantly alter growth or yield; however, increasing night temperature at a day temperature of 33�C (8 h duration) resulted in a significant decline in grain yield, primarily due to reduced seed set. The decline in grain yield at 33�C with increasing night time temperature was similar to that observed at a daylnight temperature of 36/29�C. Data from this experiment suggest that higher night time temperatures per se could increase the susceptibility of rice to sterility with a subsequent reduction in seed set and grain yield.
Preface: Why grana?
Authors: Osmond Barry
Published: January 2006

The importance of the functional flexibility of the light-harvesting complexes
of photo-system II (LHCII) in accommodating the fluctuation in the balance
between light input and metabolic capacity in plants is emphasised. This
flexibility is provided for by a relatively complex assembly of protein
subunits, the interactions between them being controlled by protonation,
xanthophyll de-epoxidation and phosphorylation. It is suggested that the
3-dimensional order imposed upon this assembly of proteins by the grana is a
vital aspect of the modulation of LHCII function. Grana establish the LHCII
conformation needed for efficient light harvesting and help prevent the dense
array of proteins from collapsing into a highly dissipative state. The grana
then allow a controlled development of non-photochemical quenching under the
driving force of violaxanthin de-epoxidation and protonation. In plants grown
under different irradiances the different grana content and xanthophyll cycle
pool size together allow maximum quantum yield in limiting light and an
appropriate level of non-photochemical quenching in excess light.
Australian Journal of Plant Physiology: Editorial Report
Authors: Martinelli Laurie , McCutchan Jennifer
Published: January 2006

Ten contrasting Acacia species were grown in glasshouses
with normal ambient CO2 or ele-vated to 700 µL
L–1. Plants were grown in sand with a complete
nutrient solution, including 5 mМ nitrate. Our objective was to determine
the degree to which photosynthesis, and the efficiency of nitrogen and water
use, were affected by growth under elevated CO2 in
contrasting plant species that differ in specific foliage area (foliage area
per unit foliage dry mass). Photosynthetic characteristics were measured at
several stages. Growth and measurement of gas exchange under 700 mL
L–1 CO2 resulted in enhanced
rates of CO2 assimilation per unit foliage area in nine
of the species. The degree of enhancement was independent of specific foliage
area. The exception was the slow-growing A. aneura,
which had lower rates of CO2 assimilation when grown and
measured at 700 µL L–1
CO2 compared to plants grown and measured at 350
µL L–1 CO2, at 50, 78
and 93 d after transplanting. Leaf conductance was reduced by growth in
elevated CO2 in only six of the species. Overall,
elevated CO2 improved the ratio of
CO2 assimi-lation to conductance by 78% and
increased CO2 assimilation per unit of foliage nitrogen
by 30% at a given specific foliage area. Detailed study of
A. saligna and A. aneura revealed
that the effects of the CO2 treatment were similarly
evident on all fully expanded phyllodes, regardless of their age.
Intercellular CO2 response curves were analysed on four
species and revealed no change in the ratio of electron transport to Rubisco
activities. However, for A. aneura and
A. melanoxylon, both electron transport and Rubisco
activities were reduced per unit foliage nitrogen, by growth under elevated
CO2 . For A. saligna and
A. implexa, these activities per unit nitrogen, were not
altered by the elevated CO2 treatment. To relate
CO2 assimilation rates to net assimilation rates (dry
matter increment per unit foliage area per day) derived from growth analysis,
between 30 and 50% of daily photosynthesis appeared to be consumed in
respiration. This proportion was not altered by CO2
treatment for seven of the Acacia species, but appeared
to be reduced in the other three. The increase in CO2
assimilation rate by growth under 700 com-pared to 350 µL
L–1 CO2 that was measured
(26%, mean of all species from two surveys), matched the increase in
net assimilation rate that had been derived from destructive sampling
(30%). We conclude that the increase in CO2
assimilation rate in the selected Acacia species was
independent of species, growth rate and foliage area per unit foliage dry
mass.
Are ovine Leydig cells able to aromatize androgens?
Authors: Biliska Barbara , Le´sniak Marcin , Schmalz Barbara
Published: January 2006

The conversion of testosterone into oestradiol by ovine Leydig cells
culturedin vitrowas studied using the non-steroidal
aromatase inhibitor CGS 16949A. Additionally, aromatase activity was detected
by immunohistochemical staining of cultured Leydig cells or cryosections. The
cells were obtained from testes of Polish Mountain rams 5–6 months old
(immature) or 12–15 months old (mature). Leydig cells were cultured
alone (controls) or incubated for 6 h in the presence of testosterone.
Aromatase inhibitor was then added to the cultures which were incubated for a
further 18 h. After a 24-h incubation period, testosterone and oestradiol
secretion were determined by testing the culture medium using
radioimmunological methods.
The addition of testosterone to the culture medium enhanced oestradiol
synthesis, suggesting that exogenous testosterone could also be aromatized to
oestradiol by ovine Leydig cells in vitro. In the
presence of CGS 16949A, the conversion of testosterone to oestradiol was
significantly suppressed in a dose-dependent manner. All Leydig cells obtained
from testes of mature rams and stained immunohistochemically were positive for
aromatase, whereas Leydig cells from immature males were negative. The
localization of immunoreactive aromatase appeared to be dependent on the age
of the donor ram. It is suggested therefore, that mature Leydig cells in the
ram are not only the site for testosterone synthesis, they are also capable of
converting androgens into oestrogens.
Comparative studies of conceptus - endometrial interactions in Large White × Landrace and Meishan gilts
Authors: Ashworth C. J. , Pickard A. R. , Miller S. J. , Flint A. P. F. , Diehl J. R.
Published: January 2006

Uterine and conceptus function were compared in mated Meishan (MS) gilts and
Large White Landrace (LW × L) gilts (n = 18
breed-1) on Days 11–15, inclusive, after oestrus.
Comparisons of individual blastocysts recovered on Day 11 and Day 12 revealed
a higher overall embryo survival in MS gilts than in LW L gilts (100·7
± 5·0% v. 69·5 ± 12·1%;
P < 0·05/. Embryo survival was higher on
Day 11 than on Day 12 (98· 6 6·0% v. 71·6
± 12·6%; P < 0 ·05/,
with most of the embryo loss between these days occurring in LW L gilts. MS
conceptuses secreted less oestradiol-17β and radiolabelled protein on both
days, but these differences were not significant. The within-litter
variability in the secretion of oestradiol-17β and radiolabelled protein
by individual conceptuses did not differ significantly between the breeds.
Concentrations of epidermal growth factor in uterine rinsings were lower in MS
gilts than in LW × L gilts on all days studied. However, two-dimensional
polyacrylamide gel electrophoresis and fluorography did not provide evidence
of additional breed differences in the profile of endometrial secretory
proteins. Consistent temporal changes in the profile of the conceptus
secretory proteins were observed among all LW × L gilts and among most
of the MS gilts. However, conceptuses cultured from 2 of 5 Day-12 MS gilts
secreted a major basic protein which was not evident in other conceptus
cultures until Day 14. Similarly, antiviral activity was detected in some
cultures of Day-13 MS conceptuses, but was absent from all Day-13 LW × L
conceptus cultures. The results also revealed a positive relationship between
ovulation rate and the incorporation of radiolabel into endometrial secretory
proteins, which was independent of breed.
Early cleavage to formation of the unilaminar blastocyst in the marsupial Antechinus stuartii: ultrastructure
Authors: Sathananthan Henry , Selwood Lynne , Douglas Isabel , Nanayakkara Kamani
Published: January 2006

The development of Antechinus stuartiifrom the 2-cell
stage to the blastocyst stage in vivo was examined by
routine transmission electron microscopy. The 2–8-cell stages had a
similar organization of organelles, whereas the 16- to 32-cell stages had
pluriblast cells and trophoblast cells forming an epithelium closely apposed
to the zona pellucida. Specialized cell–zona plugs were formed at the
8-cell stage, and primitive cell junctions appeared in later conceptuses. The
cytoplasmic organelles included mitochondria, lysosomes, aggregates of smooth
endoplasmic reticulum, lipid and protein yolk bodies and fibrillar arrays,
possibly contractile in function. Nuclei had uniformly-dispersed dense
chromatin. Nucleoli of 2–4-cell conceptuses were dense, compact and
fibrillar, and those of 8-cell conceptuses and later conceptuses were finely
granular and became progressively reticulated. The embryonic genome is
probably not switched on before the 8-cell stage. Sperm tails were detected in
cells in several early conceptuses. The yolk mass had the same organelles as
cells. Centrioles were discovered for the first time in marsupial conceptuses.
These were prominently situated at a spindle pole in a 32-cell blastomere and
were associated with a nucleus and sperm tail at the 4-cell stage. It is very
likely that the paternal centrosome is inherited at fertilization and
perpetuated in Antechinus embryos during cleavage.
Inducible nitric oxide synthase in the epithelial epididymal cells of the rat
Authors: Wiszniewska Barbara , Kurzawa Rafal , Ciechanowicz Andrzej , Machalinski Boguslaw
Published: January 2006

The expression of mRNA for inducible nitric oxide synthase (iNOS) in rat
epithelial cells of epididymis was investigated with reverse transcription
followed by polymerase chain reaction. Immunocytochemical reaction for iNOS
was performed to confirm the enzyme’ s localization in the epididymal
epithelium. Additionally, an indirect spectrophotometric method for nitric
oxide (NO) determination was applied for measurement of nitrite production by
cultured epididymal epithelial cells.
Inducible NOS mRNA was detected in freshly isolated epithelial cells, in
cultured cells without stimulation as well as in cultured cells after
stimulation by lipopolysaccharide and interferon-gamma. Inducible NOS
immunoreactivity was observed in the apical part of epithelial cells of
epididymal sections and in the cytoplasm of cells in culture. Release of
nitrite was observedin vitro in both the unstimulated
and stimulated cells of caput (1·44 ± 0·94
v. 4·37 ± 2·42 µM) and cauda
(0·69 ± 1·21 v. 5·21
± 2·76 µM) epididymis (P <
0·001).
To the best of our knowledge, this is the first study to demonstrate iNOS in
the epididymal epithelial cells of the rat. Nitric oxide released by
epididymal epithelial cells may act on cells and tissues located nearby. The
results may help explain epididymal function: sperm storage, passage and
maturation. Excessive epididymal NO production may also play a role in the
inflammatory infertility of the male.
Extra keyword: iNOS
Effects of sustained hypoxaemia with 72 hours recovery on 11β-hydroxysteroid dehydrogenase types 1 and 2 gene expression in near-term fetal sheep
Authors: Asano H. , Shearman K. , Darnel A. , Richardson B. S. , Yang K.
Published: January 2006

The study examined the effects of 8 h sustained hypoxaemia, with 72 h
recovery, on the expression of 11β-hydroxysteroid dehydrogenase (11b-HSD)
types 1 and 2 in near-term fetal sheep. Placental tissue and fetal liver and
kidney were collected at Days 135–138 gestation 72 h after 8 h sustained
hypoxaemia induced by lowering maternal inspired oxygen with
(n= 9) and without (n
= 6) metabolic acidosis or after 8 h normoxia (n
= 6). In hypoxic fetuses with metabolic acidosis, a significant
increase in the level of 11β-HSD2 mRNA in the kidney compared with
controls was correlated significantly with degree of associated fetal
acidaemia, but there were no corresponding increases in the tissue level of
11β-HSD2 activity. Hence, a time lag may exist between the mRNA and
activity. Alternatively, the translation of 11β-HSD2 mRNA may be
inhibited. In contrast, levels of 11β-HSD1 mRNA in the placenta and fetal
liver were unchanged 72 h after sustained hypoxaemia. These results indicate
that sustained fetal hypoxaemia with metabolic acidosis selectively
up-regulates 11β-HSD2 mRNA expression in the near-term fetal sheep kidney.
This may be a re-bound effect at 72 h following an initial down-regulation as
observed in a previous study.
Differential expression pattern of inhibin α and βA subunits in the ovaries of postnatal and prepubertal lambs
Authors: Braw-Tal R. , Yossefi S. , Zenou A. , Bor A.
Published: January 2006

The aim of the present study was to characterize gene and protein expression
of follistatin, inhibin α (α) and inhibin βA (βA) subunits
in the ovaries of postnatal (3-week-old) and prepubertal (14 and
20–25-week-old) lambs. Northern blot analysis revealed the presence of
two α and two βA mRNAs. In postnatal ovary the α 1·2-kb
transcript was abundant, its amount gradually falling, while the 2·0-kb
mRNA increased and became a major band at 20–25 weeks. Both βA
mRNAs, 4·5 kb and 6·0–7·5 kb, were weakly expressed
in postnatal ovary, but whereas the 4·5-kb mRNA expression remained at
a low level, that of the 6·0–7·5 kb mRNA increased about
five fold in prepubertal ovary. The ratio of total α mRNAs to the
dominant βA form (6·0–7·5 kb) varied from 1·27
at 3 weeks to 0·33 at 20–25 weeks of age. One major follistatin
mRNA of 2·5–3·6 kb was recognized and was constitutively
expressed during ovarian growth. Several molecular-mass forms of α and
βA subunits with different compositions were seen in prepubertal compared
with postnatal ovaries, the latter exhibiting more active follicular growth.
In summary, ovine ovaries undergo distinct changes early in life, both
morphological and functional, and show a changing pattern of inhibin subunit
expression.
Postnatal weight of calves derived from in vitro matured and in vitro fertilized embryos developed under various oxygen concentrations
Authors: Iwata H. , Minami N. , Imai H.
Published: January 2006

In the present study, weights of calves (14 days after birth) derived from
embryos of a homogeneous line (Tajima line) of Japanese Black Cow, cultured
in vitro under various oxygen conditions was examined.
In vitro matured and fertilized oocytes were incubated
for 48 h in modified synthetic oviduct fluid medium under 5% CO
2in air and embryos reaching at least the 5-cell stage
were selected for further culture under various gas conditions (high oxygen
tension: 5% CO 2 in air; low oxygen tension: 5% O
2 , 5% CO 2 , 90% N
2 ) for 5 days. Embryos that developed to the blastocyst
stage were transferred to Holstein cows or cryopreserved until transfer. When
embryos were cultured under high oxygen tension and cryopreserved, the weights
of male calves (at 14 days) were significantly heavier than in the other
groups. However, there was no significant difference in gestation lengths of
male calves. In female calves, no difference was observed in either the weight
or gestation length of calves irrespective of oxygen tension during the
culture period or embryo conditions (fresh or frozen). From the results of the
present study, it is suggested that the oxygen concentration during culture
and cryopreservation synergistically induced the production of overweight male
calves without influencing gestation length.
A dipstick immunoassay to rapidly measure serum oestrone sulfate concentrations in horses
Authors: Henderson K. , Stewart J.
Published: January 2006

A dipstick, competitive immunoassay for rapidly measuring serum oestrone
sulfate (OS) concentrations in horses was developed to distinguish mares 100
or more days pregnant from non-pregnant animals. 6-Ketoestrone
6-carboxymethyloxime conjugated to bovine serum albumin (oestrone CMO-BSA) was
‘dotted’ 25 mm from the bottom edge of 45 5 mm strips of
polyester-film-supported cellulose nitrate membrane, pore size 3 m. The strips
were blocked, dried and a 15 5-mm cellulose absorbent sink attached 10 mm from
the top of each strip. The manufactured dipsticks were stored with desiccant
at room temperature until used. A monoclonal antibody recognizing OS was
coated onto uniform, blue-dyed polystyrene microspheres (mean diameter, 0.31
m) by adsorption. After blocking, several washes and resuspension by
sonication, the antibody-coated microspheres were stored at 4˚C. The
concentrations of oestrone CMO-BSA dotted onto the dipsticks and OS antibody
coated onto the microspheres were optimized to produce a test that allowed
maximum discrimination between the concentrations of OS found in serum of
mares 100 or more days pregnant (i.e. >30 ng OS mL
–1 ) relative to those found in non-pregnant mares
(i.e. <10 ng OS mL –1 ). To perform the
dipstick test, 30 L of carrier buffer, 10 L of OS antibody-coated microspheres
and 10 l of OS standard or serum sample were pipetted into a microwell and
mixed. A dipstick was placed in the solution. All the liquid migrated up the
dipstick into the absorbent sink within 15–20 min leaving a blue dot
where the OCMO-BSA had been placed. The intensity of colour of the blue dot,
which correlated inversely with the concentration of OS in the standard or
serum sample, was assessed visually and by computer image analysis. An OS
concentration less than 5 ng mL –1 produced a deep
blue dot, 20 ng/ml a light blue dot and a concentration greater than 50 ng
mL –1 a very faint blue dot, or none at all. Serum
samples from 42 non-pregnant mares and 40 mares over 100 days pregnant were
analysed by the dipstick test. All the serum samples from non-pregnant mares
produced dipsticks with deep blue dots that ranged in intensity from 20 to 38
colour intensity units, equivalent to OS concentrations less than 7 ng mL
–1 . Sera from all the pregnant mares generated
dipsticks with either faint blue dots or none at all (i.e. £=5
colour intensity units, equivalent to OS concentrations >40 ng mL
–1 ). It is concluded that this novel, rapid
dipstick immunoassay offers a practical, alternative means of analysing serum
OS concentrations in horses, and enables mares that are 100 or more days
pregnant to be distinguished from those that are not pregnant.
Plasma concentrations of thyroxine and growth hormone in the developing marsupial bandicoot, Isoodon macrourus
Authors: Saunders M. C. , Gemmell R. T. , Curlewis J. D.
Published: January 2006

Plasma concentrations of thyroxine (T 4 ) and growthhormone (GH) were measured in the developing bandicoot from 21 through to 69days post partum. Thyroxine concentrations increased from 7 ng mL–1 at 21 days post partum to reach a maximum ofaround 40 ng mL –1 approximately 40 days postpartum. After this time, plasma T 4concentrations decreased until about 50 days post partum, when levels were not different fromthose in the adult (9.2 ± 0.7 ng mL –1 ,n=10). In contrast, GH concentrations weregreatest early in pouch life, with a maximum concentration of 88.2 ng mL–1 at 24 days post partum, and thereafter declinedto adult levels (4.9 ± 0.9 ng mL –1 ,n= 7) by about 60 days post partum. Thetemporal relationship between T4 and GH in thedeveloping bandicoot is similar to that seen in developing eutherian mammals,but in the latter species, peak plasma T4and the declinein GH occur before or soon after parturition, whereas in the bandicoot theseevents occur more than one month post partum. This comparison betweeneutherian mammals and a marsupial indicates that the timing of these endocrinechanges correlates with key developmental or maturational changes rather thanthe time of parturition.
Oxytocin-stimulated phosphoinositide hydrolysis and prostaglandin F2α secretion by luminal epithelial, glandular epithelial and stromal cells from pig endometrium. II. Responses of cyclic, pregnant and pseudopregnant pigs on Days 12 and 1
Authors: Uzumcu Mehmet , Carnahan Kevin G. , Braileanu Gheorghe T. , Mirando Mark A.
Published: January 2006

In pigs, the exact mechanism for the shift in endometrial PGF
2α secretion from an endocrine to
an exocrine mode during pregnancy recognition is not known. The objective of
this study was to examine whether this shift involved a change in the
responsiveness of luminal epithelial, glandular epithelial and stromal cells
to 0 or 100 nM oxytocin. Luminal epithelial cells, glandular epithelial cells
and stromal cells were isolated from cyclic, pregnant or oestrogen-induced
pseudopregnant gilts on Day 12 (Experiment 1) or Day 16 (Experiment 2) post
oestrus (oestrus = Day 0). For cells obtained on Day 12, oxytocin
stimulated PGF2α secretion by
stromal cells (P<0.01) similarly for each
reproductive status, whereas oxytocin stimulated PGF
2α secretion from luminal and
glandular epithelial cells (P<0.05) from pregnant and
pseudopregnant gilts but not from cyclic gilts. For both concentrations of
oxytocin, mean PGF2α secretion
was less (P<0.05) from stromal cells of pregnant than
cyclic gilts. For cells obtained on Day 16, oxytocin stimulated PGF
2α release from stromal cells of
cyclic gilts but not from stromal cells of pregnant gilts. Mean PGF
2α secretion also was less
(P<0.05) from stromal cells of pregnant gilts than
cyclic gilts. Oxytocin tended to stimulate PGF
2α release
(P<0.07) from glandular epithelial cells of cyclic
but not pregnant or pseudopregnant gilts. Luminal epithelial cells from all
reproductive statuses were similarly unresponsive to oxytocin. In conclusion,
the increased PGF2α secretory
response to oxytocin of luminal and glandular epithelial cells from pregnant
gilts on Day 12, combined with the decreased response of stromal cells from
pregnant gilts on Days 12 and 16, may contribute, in part, to the shift in
endometrial PGF2α secretion from
an endocrine to an exocrine direction during early pregnancy in pigs.
Decrease in voluntary feed intake and pulsatile luteinizing hormone secretion after intracerebroventricular infusion of recombinant bovine leptin in mature male sheep
Authors: Blache Dominique , Celi Pietro , Blackberry Margaret A. , Dynes Robyn A. , Martin Graeme B.
Published: January 2006

The aim of the present study was to determine whether leptin might play a role
in the gonadotrophic response of mature merino rams to changes in the level of
nutrition in rams fed ad libitum. Recombinant bovine
leptin was infused intracerebroventricularly and voluntary food intake (VFI)
and luteinizing hormone (LH) pulse frequency were measured. In Experiment 1,
rams (n = 5) were infused for 24 h per day for 5
days with vehicle or with leptin (0.04, 0.4 and 4.0g h
–1 ). All doses decreased both VFI and LH pulse
frequency. In Experiment 2, rams were infused for 24 h per day for 5 days with
vehicle (n = 10) or leptin (4 g h
–1; n= 5); a
sub-group of 5 controls was pair-fed to the leptin-infused group to control
for effects of changes in feed intake. LH pulse frequency was reduced equally
in both the leptin-infused and pair-fed groups. Leptin did not affect other
systems controlled by the hypothalamic–pituitary axis. Thus, rather than
stimulate LH secretion, intracerebral leptin specifically inhibits it by
reducing food intake, so it is unlikely that effects of nutrition on the
reproductive axis in mature rams involves leptin as a single blood-borne
signal. A range of nutritional or metabolic inputs may be needed, and perhaps
interconnections between neural centres that control appetite and
reproduction.
Participation of glucose in the synthesis of glycoproteins in preimplantation mouse embryos
Authors: Wales RG , Hunter J
Published: January 2006

Electrophoretic separation of solubilized embryos incubated for 24 h in the presence of [U-14C]glucose indicated incorporation of glucose carbon into a number of protein bands. Treatment of nitrocellulose blots of electrophoretograms with glucosidases had no effect on incorporated counts, confirming that the labelled bands were not due to protein bound glycogen. Furthermore, addition of 0.1 microgram mL-1 tunicamycin to the incubation medium virtually eliminated incorporation of glucose into the protein bands but had no effect on the pattern or rate of incorporation of labelled amino acids in parallel experiments. Also the pattern of labelling of protein by glucose was reflected in the pattern of binding of Con A to the nitrocellulose blots. There were quantitative and qualitative changes in labelling as development progressed. For embryos cultured from the 2-cell stage, a small amount of label was incorporated in two major bands at relative mobility (Mr) 69 and 97 K. With culture from the 8-cell stage, three additional major bands (33, 44 and 56 K) were labelled. Embryos cultured from the morula stage showed a different profile of incorporation; there was much more active labelling, and eight major and a number of minor radioactive bands were identified. Whilst tunicamycin suppressed glucose incorporation into glycoproteins and inhibited compaction of embryos, it had little effect on other parameters of metabolism during incubation in its presence for 24 h. No significant effects of the metabolite on protein synthesis, glycogen storage, lactate production or overall macromolecular synthesis were evident. By contrast, the anabolic metabolism of embryos decompacted by long periods of exposure to tunicamycin was severely reduced although glycolysis was still unaffected. Amphomycin at very high concentration (500 micrograms mL-1) was toxic to embryos but at concentrations up to 250 micrograms mL-1 had no effect on compaction and development of blastocysts. Addition of monensin to the incubation medium [16 micrograms mL-1] did not interfere with the development of either 2-cell or 8-cell embryos to blastocysts.
Cloning of a marsupial k-casein cDNA from the brushtail possum (Trichosurus vulpecula)
Authors: Stasiuk Susan J. , Summers Emma L. , Demmer Jerome
Published: January 2006

The main role of κ-casein in milk is to stabilize the formation of casein
micelles. Although marsupial milk contains casein micelles, κ-casein had not
been identified in any species. In these experiments, the first marsupial
κ-casein has been prepared as enriched casein fractions and the cDNA cloned
from the brushtail possum (Trichosurus vulpecula).
Possum κ-casein is a 158 amino acid peptide that shares low amino acid
sequence identity (20–30%) with that of eutherian κ-caseins. In
the gut of suckling young, casein micelles clot when κ-casein is cleaved by
chymosin at a specific site. Eutherian κ-casein sequences are classified
according to the sequence of the chymosin cleavage site: Phe-Met, Phe-Ile or
Phe-Leu. Possum κ-casein appears to form a separate class, with a putative
chymosin cleavage site of Phe-Ala, which is different from that found in
eutherian mammals. Other features of κ-caseins, such as the location of the
N-terminal cysteine, solubility in the presence of calcium, and the
O-glycosylation sites on threonine residues in the C-terminus of the molecule,
are conserved in the possum sequence. The κ-casein gene was expressed
throughout lactation in the mammary gland, and although mRNA levels of κ-,
α- and β-casein varied between animals there appeared to be a
correlation in the expression of these genes within an individual animal. This
suggests that a common transcription regulatory region may be controlling
expression of all three genes in the possum.
Alterations of the pituitary - gonadal axis in the neonatal blue fox (Alopex lagopus) exposed to prenatal handling stress
Authors: Osadchuk Ludmila V. , Braastad Bjarne O. , Huhtaniemi Ilpo , Bakken Morten
Published: January 2006

Handling is a stressor for blue foxes. The influence of preterm handling (1
min daily) of vixens was investigated in 68, 10-day-old cubs, 34 male and 34
female. Body, gonadal and pituitary weight, ano-genital distance, gonadal
testosterone and oestradiol content and in vitro
production, and pituitary LH content were measured in all cubs. The gonads
were frozen or incubated in vitro with, or without,
added hCG (2.5 IU per sample). The gonadal incubates and homogenates were
analysed for testosterone and oestradiol by radioimmunoassay and the pituitary
homogenates for LH by immunofluorometric assay. The results indicate that
neonatal fox gonads actively produce steroids and that there are significant
sex differences in basal steroid production and response of the gonads to hCG,
and in pituitary LH content. Maternal stress resulted in a significant
reduction of morphometric and hormonal measures of the reproductive system in
neonatal blue foxes, with more drastic effects in female cubs. Gonadal weights
were lower in cubs of both sexes from stressed vixens (65.7 4.3
v. 50.6 1.8 mg for the ovaries and 23.2 1.0
v. 17.7 1.0 mg for the testes, control
v. stressed animals, P<0.01).
The ano-genital distance in female offspring of stressed vixens was reduced
(1.1 0.04 v. 0.9 0.03 cm,
P<0.01). Basal ovarian oestradiol and testosterone
production were decreased in cubs from prenatally stressed animals in
comparison with controls (43.5 3.5 v. 32.6 3.7 pg
ovary–1 h–1 and 0.40
0.16 v. 0.12 0.03 ng ovary–1
h–1, P<0.05). Prenatal
stress did not affect either pituitary weights or LH content in either sex.
There were no significant differences in ano-genital distance, testicular
content of testosterone, or in vitro testosterone
production between control and treated male cubs. In conclusion, these
findings suggest that prenatal handling stress impaired the neonatal
reproductive development of the female offspring, but had no marked effects on
males. Sex-specific effects of prenatal handling stress on the reproductive
development in foxes may be linked with the gender differences in responses of
the hypothalamus–pituitary–adreno-cortical axis to stress
conditions in this species.
New taxa of Mycovellosiella parasitising forest plants of the Indian subcontinent
Authors: Bhalla Kirti , Singh Sanjay K. , Srivastava A.K.
Published: January 2006

Four new taxa of Mycovellosiella Rangel,
M. antidesmatis sp. nov.,
M.eupatorii-odorati (Yen) Yen var.
asteracearum var. nov., M.lantanae
(Chupp) Deighton var. verbenacearum var. nov. and
M.moghamiae sp. nov., collected on
Antidesma ghissambila (Stilaginaceae),
Eupatorium sp. (Asteraceae),
Lantana camara (Verbenaceae) and
Moghamia prostrata (Fabaceae), respectively, are
described, illustrated and compared with allied taxa.
New species of Torrendia (Fungi, Agaricales) from remnant woodlands in the wheatbelt region of Western Australia
Authors: Bougher Neale L.
Published: January 2006

Two new species of sequestrate (truffle-like fungi) Basidiomycetes of the
putatively ectomycorrhizal genus Torrendia Bres. with
contrasting basidiome morphology are described from remnant patches of
eucalypt woodland in the wheatbelt of Western Australia:
Torrendia grandis Bougher and
Torrendia inculta Bougher.Like other species of
Torrendia, they have basidiomes which develop and mature
mostly underground but may break through to the soil surface at a late stage
of maturity. The gleba of Torrendia species does not
become powdery. A comparison of the main diagnostic features of all known taxa
of Torrendiais provided.
T. grandishas stocky basidiomes with an agaric-like
pileus. T. inculta has a gleba which fragments during
stipe elongation. The basidiome development of
T. incultaisdescribed and illustrated, and some possible
mechanisms of spore dispersal are discussed.
Marine macroalgae from the Gulf of Carpentaria, tropical northern Australia
Authors: Phillips J. A. , Conacher C. , Horrocks J.
Published: January 2006

Over the last two decades, CSIRO surveys of the seagrass communities in the
south-western Gulf of Carpentaria and at Groote Eylandt, the Northern
Territory, have provided opportunities for the collection of marine macroalgae
from this poorly explored, remote region. Although the cruises did not
concentrate on macroalgal communities which typically grow on rocky
substrates, 64 specific and subspecific taxa of marine Chlorophyta,
Phaeophyceae and Rhodophyta were collected, including 30 species newly
recorded for the Gulf. The majority of Gulf species also occur on the tropical
eastern Australian coast. One hundred and thirteen macroalgal taxa are now
known to occur in the Gulf of Carpentaria, the number from the present study
supplemented by collections from the 1948 Arnhem Land Expedition and from an
ethnobiological study on Groote Eylandt during the 1970s. Twelve species are
recorded by all three Gulf studies and 23 species are reported by two studies.
The relatively low number of species common to more than one study is thought
to result from each study's narrow sampling window which fails to
adequately document the considerable spatial and temporal variability of
macroalgal species. Accordingly, the number of species presently recorded for
the Gulf is considered to be an underestimate of macroalgal biodiversity for
the region. It is clear that further detailed taxonomic and ecological
investigations are urgently required before the full extent of macroalgal
biodiversity in tropical Australia can be appreciated.
New Plectronidium and Tunicago species (mitosporic fungi) from Australia
Authors: Alcorn J. L. , Sutton B. C.
Published: January 2006

Plectronidium cultriforme, sp. nov., and
Tunicago triodiae, sp. nov., found on
Triodia sp. in Australia are described and illustrated.
The generic circumscription of Plectronidium is
broadened to include sporodochial conidiomata and phialidic conidiogenous
cells borne on branched conidiophores.
Enumeration of the species and infraspecific taxa of Melaleuca (Myrtaceae) occurring in Australia and Tasmania
Authors: Craven L. A. , Lepschi B. J.
Published: January 2006

The genus Melaleuca currently is the subject of
taxonomic revision. In this paper, the 219 Australian and Tasmanian species of
Melaleuca sens. Austral. auctt. that are considered to
represent Melaleuca are listed together with their
infraspecific taxa, taxonomic and nomenclatural synonyms are given, and new
names resulting from changes in taxonomic rank and/or the recognition of
new taxa are validated. Identification keys are also provided. Of the new
names, 48, 3 and 2 result from the recognition of new species, new subspecies
and new varieties, respectively, 7 from new combinations and 1 from the
provision of a new name. An invalidly published name is validated. The epithet
and authority of new taxa are: amydra Craven,
apodocephala subsp. calcicola
Barlow ex Craven, barlowii Craven,
beardii Craven, boeophylla Craven,
borealis Craven, brophyiCraven,
caeca Craven, calyptroides Craven,
campanae Craven, carrii Craven,
clavifolia Craven, condylosa
Craven, croxfordiae Craven, delta
Craven, eulobata Craven, eurystoma
Barlow ex Craven, fabri Craven,
glena Craven, grieveana Craven,
halophila Craven, hnatiukii
Craven, hollidayi Craven,
huttensis Craven, idana Craven,
johnsonii Craven, keigheryi
Craven, laetifica Craven, lara
Craven, leuropoma Craven,
linguiformis Craven, longistaminea
subsp. spectabilis Barlow ex Craven,
orbicularis Craven, papillosa
Turcz. ex Craven, pentagona var.
raggedensis Craven, phoidophylla
Barlow ex Craven, plumea Craven,
podiocarpa Barlow ex Craven,
procera Craven, ryeae Craven,
sapientes Craven, similis Craven,
societatis Craven, stereophloia
Craven, stramentosa Craven,
thapsina Craven, tinkeri Craven,
tuberculata var. macrophylla
Craven, venusta Craven,
villosisepala Craven, viminea
subsp. demissa Quinn ex Craven,
wonganensis Craven, zonalis
Craven; of new combinations: dempta (Barlow) Craven,
eximia (K.J.Cowley) Craven,
longistaminea (F.Muell.) Barlow ex Craven,
monantha (Barlow) Craven, penicula
(K.J.Cowley) Craven, tuberculata var.
arenaria (C.A.Gardner) Craven,
virgata (Benth.) Craven; of the new name:
systena Craven; and of the validated name:
nematophylla F.Muell. ex Craven.
Chromosome numbers in Craspedia, Ewartia and Pterygopappus (Compositae: Gnaphalieae)
Authors: Dawson Murray I. , Breitwieser Ilse , Ward Josephine M.
Published: January 2006

Somatic chromosome counts are documented for seven species of the Gnaphalieae
(Compositae) from Australia: Craspedia alpina Backh.
(2n=
10x2 = 110) and
C. glauca (Labill.) Spreng.
(2n=
4x2 = 44),
Ewartia catipes (DC.) Beauverd,
E. nubigena Beauverd and
E. planchonii (Hook.f.) Beauverd (all
2n=
2x2 = 28),
E. meredithiae (F.Muell.) Beauverd
(2n=
4x2 = 56) and
Pterygopappus lawrencei Hook.f.
(2n =
2x2 = 28).
RF9, a potent and selective neuropeptide FF receptor antagonist, prevents opioid-induced tolerance associated with hyperalgesia
Authors: Simonin Frédéric , Schmitt Martine , Laulin Jean-Paul , Laboureyras Emilie , Jhamandas Jack H. , MacTavish David , Matifas Audrey , Mollereau Catherine , Laurent Patrick , Parmentier Marc , Kieffer Brigitte L. , Bourguignon Jean-Jacques , Simonnet Guy
Published: January 2006

Neuropeptide FF (NPFF) has been proposed to play a role in pain modulation, opioid tolerance, and several other physiological processes. However, pharmacological agents that would help define physiological roles for this peptide are still missing. Here we report the discovery of a potent and selective NPFF receptor antagonist, RF9, that can be administered systemically. This compound does not show any effects by itself but can block efficiently the increase in blood pressure and heart rate evoked by NPFF. When chronically coinjected with heroin, RF9 completely blocks the delayed and long-lasting paradoxical opioid-induced hyperalgesia and prevents the development of associated tolerance. Our data indicate that NPFF receptors are part of a bona fide antiopioid system and that selective antagonists of these receptors could represent useful therapeutic agents for improving the efficacy of opioids in chronic pain treatment.
Point mutations in the aromatic/arginine region in aquaporin 1 allow passage of urea, glycerol, ammonia, and protons
Authors: Beitz Eric , Wu Binghua , Holm Lars M. , Schultz Joachim E. , Zeuthen Thomas
Published: January 2006

Water-specific aquaporins (AQP), such as the prototypical mammalian AQP1, stringently exclude the passage of solutes, ions, and even protons. Supposedly, this is accomplished by two conserved regions within the pore, a pair of canonical asparagine–proline–alanine (NPA) motifs, the central constriction, and an aromatic/arginine (ar/R) constriction, the outer constriction. Here, we analyzed the function of three residues in the ar/R constriction (Phe-56, His-180, and Arg-195) in rat AQP1. Individual or joint replacement of His-180 and Arg-195 by alanine and valine residues, respectively (AQP1-H180A, AQP1-R195V, and AQP1-H180A/R195V), did not affect water permeability. The double mutant AQP1-H180A/R195V allowed urea to pass. In line with the predicted solute discrimination by size, replacement of both Phe-56 and His-180 (AQP1-F56A/H180A) enlarged the maximal diameter of the ar/R constriction 3-fold and enabled glycerol and urea to pass. We further show that ammonia passes through all four AQP1 mutants, as determined (
i
) by growth complementation of yeast deletion strains with ammonia, (
ii
) by ammonia uptake from the external solution into oocytes, and (
iii
) by direct recordings of ammonia induced proton currents in oocytes. Unexpectedly, removal of the positive charge in the ar/R constriction in AQP1-R195V and AQP1-H180A/R195V appeared to allow the passage of protons through AQP1. The data indicate that the ar/R constriction is a major checkpoint for solute permeability, and that the exquisite electrostatic proton barrier in AQPs comprises both the NPA constriction as well as the ar/R constriction.
Role of
Src
in C3 transient receptor potential channel function and evidence for a heterogeneous makeup of receptor- and store-operated Ca
2+
entry channels
Authors: Kawasaki Brian T. , Liao Yanhong , Birnbaumer Lutz
Published: January 2006

Receptor-operated Ca
2+
entry (ROCE) and store-operated Ca
2+
entry (SOCE) are known to be inhibited by tyrosine kinase inhibitors and activation of C-type transient receptor potential channel (TRPC) isoform 3 (TRPC3), a cation channel thought to be involved in SOCE and/or ROCE, was recently shown to depend on
src
tyrosine kinase activity. What is not known is the step at which
src
acts on TRPC3 and whether the role for tyrosine kinases in ROCE or SOCE is a general phenomenon. Using
in vitro
and in cell protein-protein interaction assays we now report that
src
phosphorylates TRPC3 at Y226 and that formation of phospho-Y226 is essential for TRPC3 activation. This requirement is unique for TRPC3 because (
i
) mutation of the cognate tyrosines of the closely related TRPC6 and TRPC7 had no effect; (
ii
) TRPC6 and TRPC7 were activated in
src
-,
yes
-, and
fyn
-deficient cells; and (
iii
)
src
, but not
yes
or
fyn
, rescued TRPC3 activation in
src
-,
yes
-, and
fyn
-deficient cells. The Src homology 2 domain of
src
was found to interact with either the N or the C termini of all TRPCs, suggesting that other tyrosine kinases may play a role in ion fluxes mediated by TRPCs other than TRPC3. A side-by-side comparison of the effects of genistein (a general tyrosine kinase inhibitor) on endogenous ROCE and SOCE in mouse fibroblasts, HEK and COS-7 cells, and ROCE in HEK cells mediated by TRPC3, TRPC6, TRPC7, and TRPC5 showed differences that argue for ROCE and SOCE channels to be heterogeneous.