bluuebunny/crossref_metadata_2025 huggingface dataset:
Agrobacterium-mediated transformation of Australian rice cultivars Jarrah and Amaroo using modified promoters and selectable markers
Authors: Upadhyaya Narayana M. , Surin Brian , Ramm Kerrie , Gaudron Judy , Schünmann Petra H. D. , Taylor William , Waterhouse Peter M. , Wang Ming-Bo
Published: September 2002

We report the first
successfulAgrobacterium-mediated transformation of
Australian elite rice cultivars, Jarrah and Amaroo, using binary vectors with
our improved promoters and selectable markers. Calli derived from mature
embryos were used as target tissues. The binary vectors contained
hph(encoding hygromycin resistance) or
bar (encoding herbicide resistance) as the selectable
marker gene and uidA (gus) or
sgfpS65T as the reporter gene driven by different
promoters. Use of Agrobacterium strain AGL1 carrying
derivatives of an improved binary vector pWBVec8, wherein the CaMV35S driven
hph gene is interrupted by the castor bean catalase 1
intron, produced a 4- fold higher number of independent transgenic lines
compared to that produced with the use of strain EHA101 car-rying the binary
vector pIG121-Hm wherein the CaMV35S driven hph is
intronless. The Ubiquitin promoter produced 30-fold
higher ß-glucuronidase (GUS) activity (derivatives of binary vector
pWBVec8) in transgenic plants than the CaMV35S promoter (pIG121-Hm). The two
modified SCSV promoters produced GUS activity com-parable to that produced by
the Ubiquitin promoter. Progeny analysis
(R1) for hygromycin resistance and GUS activ-ity with
selected lines showed both Mendelian and non-Mendelian segregation. Lines
showing very high levels of GUS activity in T0 showed a
reduced level of GUS activity in their T1 progeny, while
lines with moderate levels of GUS activity showed increased levels in
T1 progeny. Stable heritable green fluorescent protein
(GFP) expression was also observed in few transgenic plants produced with the
binary vector pTO134 which had the CaMV35S promoter-driven selectable marker
gene bar and a modified CaMV35S promoter-driven reporter
gene sgfpS65T.
Phytochrome, photosynthesis and flowering of Arabidopsis thaliana: photophysiological studies using mutants and transgenic lines
Authors: Bagnall David J. , King Rod W.
Published: September 2002

A number of phytochrome mutants have been examined for involvement in high
irradiance (HIR) or red/far-red (R/FR) end-of-day (EOD) photoresponses
during flowering of the long-day (LD) plant,
Arabidopsis thaliana (L.) Heynh. A large component of
phytochrome A (phyA) response is shown to involve an indirect effect via
photosynthesis. When grown autotrophically in soil at a low irradiance (80 mol
m–2 s–1), the
phyA-211 mutant flowered extremely late compared with
wild type and its leaf area was halved, both effects being reversed by
increase in photosynthetic irradiance. Supplying sucrose via agar led to very
early flowering with little indication of an additional direct phyA HIR. For
light-stable phytochrome apoprotein mutants (phyB, phyD)
or chromophore mutants (hy1, hy2), flowering was early
and R/FR photoreversible EOD response was erased. Conversely, flowering
was delayed in a transgenic line overexpressing the PHYB apoprotein. The FR
EOD promotion of flowering via phyB was retained in darkness, brief night
interruptions mimicking LD response. This novel finding emphasizes the
importance of phyB-like phytochromes, with phyA acting indirectly. Whether
phyB influences time measurement remains uncertain as we found no rhythmicity
in this response to night interruptions. Overall, the role(s) of phytochromes
in the regulation of flowering of Arabidopsis include
EOD phyB-type response, a minor phyA photoperiodic response, and a large
indirect phyA effect involving photosynthesis.
Analysis of a promoter for the NADH - glutamate synthase gene in rice (Oryza sativa): cell type-specific expression in developing organs of transgenic rice plants
Authors: Kojima Soichi , Kimura Michiko , Nozaki Yukine , Yamaya Tomoyuki
Published: September 2002

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999
The entire 3.7 kbp 5´-upstream region (–2840 to +886) from
the translational start codon of NADH–glutamate synthase
(NADH–GOGAT, EC 1.4.1.14) gene from rice
(Oryza sativa L.) or the region sequentially deleted
from the 5´-end was fused with the β−glucuronidase (GUS)
reporter gene. The chimeric gene was introduced into calli derived from rice
scutellum via Agrobacterium tumefaciens-mediated
transformation and tissue-specific GUS activity determined in T0 generations.
When the entire region was fused, GUS activity was detected in vascular
bundles of the developing leaf blade and in dorsal and lateral vascular
bundles of developing grains. This corresponds with our previous
immunodetection of NADH–GOGAT protein (Hayakawa
et al., Planta
193, 455–460, 1994). A series of deletion
experiments showed that a 149-nucleotide region between –142 and +7
was essential for promoter activity in the NADH–GOGAT gene.
The paraveinal mesophyll: a specialized path for intermediary transfer of assimilates in legume leaves
Authors: Lansing Alexis J. , Franceschi Vincent R.
Published: September 2002

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999
The distance between sites of synthesis of assimilates and the site of phloem
loading can be large, and specialized leaf cell layers such as the paraveinal
mesophyll (PVM) might act to enhance the efficiency of transport. A number of
techniques were used to analyse PVM of legume leaves with respect to a
hypothesized function in transfer of assimilates between tissues. Of 39 legume
species examined, PVM was found in 22. Leaves of all PVM-containing species
had multiple palisade parenchyma layers, while non-PVM species generally had
only one distinct palisade layer. Morphometric analysis identified a
significant correlation between PVM presence and greater numbers of palisade
cells per unit leaf surface area. Comparison of photosynthetic rates of four
PVM and four non-PVM species showed the PVM species had higher rates on a leaf
area basis than all but one of the non-PVM species. Microautoradiography of
14CO2 pulse–chase studies in
soybean demonstrated PVM is an intermediary tissue in transfer of assimilates
to vascular bundles. In addition, PVM cells but not mesophyll cells, were
enriched in a sucrose binding protein previously found to be associated with
sucrose-transporting tissues. The structural, positional and transport data
support the hypothesis that the PVM acts as a transport pathway between the
vascular system and photoassimilatory cells of the leaf, and has probably
evolved to overcome diffusion limitations imposed by multiple palisade layers.
Ozone inhibits phloem loading from a transport pool: compartmental efflux analysis in Pima cotton
Authors: Grantz David A. , Farrar John F.
Published: September 2002

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999
The rate of export of recent photoassimilate from source leaves of Pima cotton
(Gossypium barbadense L.) is inhibited by ozone
(O3). To characterize these effects on export, source
leaves of Pima cotton were exposed to pulses (0.75 h) of
O3 (0.0, 0.2, 0.5 and 0.8 L
L–1) followed by pulses of
14CO2. Leaves were monitored by
gas exchange and with a Geiger–Muller tube, for a sufficient period to
characterize carbon assimilation (A) and a rapid and a
slower phase of export. Double exponential decay functions (two-compartment
model) were fitted and a compartmental analysis conducted.
O3 reduced by half the fast rate constant describing
export from a transport pool, without affecting the rate constants for
transport from or to a storage compartment. Measured soluble sugar contents
increased slightly from control concentrations (1.2 g C
m–2) by about 5–10% at all
O3 concentrations. The calculated soluble sugar content
in the transport pool increased from about 200 to 300 mg C
m–2 with increasing exposure to
O3. The calculated storage pool did not respond to
O3 but exceeded measured contents. This discrepancy is
attributed to starch deposition and mobilization, which are not considered in
the two-compartment model, uncertainties in slower decay parameters, and
non-steady-state A induced by O3
exposure. Specific inhibition of rapid efflux suggests oxidant damage at the
plasmalemma or plasmodesmata of mesophyll or phloem companion cells, and
little effect on the tonoplast. A was affected less than
export. Future research should target oxidation of components involved in
phloem loading.
D1 protein turnover and carotene synthesis in relation to zeaxanthin epoxidation in rice leaves during recovery from low temperature photoinhibition
Authors: Xu Chang-Cheng , Kuang Tingyun , Li Liangbi , Lee Choon-Hwan
Published: September 2002

The relationship between D1 protein turnover,
carotene synthesis and zeaxanthin epoxidation was exam-ined in rice
(Oryza sativa L.) leaves during recovery subsequent to
chilling treatments at 500 (moderate light) or 1000 mol photons m
–2 s –1 (high light)
for 3 h. When recovery was monitored in the light, the decrease in the level
of zeaxanthin was closely paralleled by the slow increase in the efficiency of
photosystem (PS) II. Both these processes were greatly slowed down in the
presence of lincomycin, an inhibitor of chloroplast-coded protein synthesis.
In leaves chilled in moderate light, the inhibitory effect of lincomycin on
zeaxanthin decrease was largely eliminated by infiltration with
dithiothreitol, an inhibitor of de-epoxidase, suggesting a stimulation of
violaxanthin de-epoxidation rather than an inhibition of zeaxanthin
epoxidation in the presence of lincomycin. In high-light-chilled leaves,
lincomycin had little impact on violaxanthin de-epoxidation but strikingly
blocked the process of zeaxanthin epoxidation. Furthermore both PSII recovery
and zeaxanthin epoxidation in high-light-chilled leaves were almost completely
suppressed by incubation with either fluridone or norflurazon, two inhibitors
of carotene synthesis. The possible reason for parallel changes in the level
of zeaxanthin and PSII efficiency during recovery from photoinhibition is
discussed.
Regulation of assimilate partitioning in leaves
Authors: Lewis Charlotte E. , Noctor Graham , Causton David , Foyer Christine H.
Published: September 2002

Concepts of the regulation of assimilate
partitioning in leaves frequently consider only the allocation of carbon
between sucrose and starch synthesis, storage and export. While carbohydrate
metabolism accounts for a large proportion of assimilated carbon, such
analyses provide only a restricted view of carbon metabolism and partitioning
in leaf cells since photosynthetic carbon fixation provides precursors for all
other biosynthetic pathways in the plant. Most of these precursors are
required for biosynthesis of amino acids that form the building blocks for
many compounds in plants. We have used leaf carbon : nitrogen ratios to
calculate the allocation of photosynthetic electrons to the assimilation of
nitrogen necessary for amino acid formation, and conclude that this allocation
is variable but may be higher than values often quoted in the literature.
Respiration is a significant fate of fixed carbon. In addition to supplying
biosynthetic precursors, respiration is required for energy production and may
also act, in both light and dark, to balance cellular energy budgets. We have
used growth CO2 concentration and irradiance to modify
source activity in Lolium temulentum in order to explore
the interactions between photosynthetic carbon and nitrogen assimilation,
assimilate production, respiration and export. It is demonstrated that there
is a robust correlation between source activity and foliar respiration rates.
Under some conditions concomitant increases in source activity and respiration
may be necessary to support faster growth. In other conditions, increases in
respiration appear to result from internal homeostatic mechanisms that may be
candidate targets for increasing yield.
Acetohydroxy acid reductoisomerase of wheat
Authors: Donadini Roberta , Copeland Les
Published: September 2002

Acetohydroxy acid reductoisomerase (EC
1.1.1.86, AHAR) was purified to a high degree from green shoots of wheat
(Triticum aestivum L. cv. Vulcan). The enzyme was
localised in the chloroplasts, and activity was at a maximum approximately 4 d
after germination. The subunit molecular mass of wheat AHAR was 57 kD and
activity of the native enzyme had an elution volume from size exclusion
columns that corresponded to a molecular mass of 47 kD. The enzyme did not
require the addition of Mg 2+ ions to reaction
mixtures for activity. The Km values for
(R,S)-2-acetolactate and
(R,S)-2-aceto-2-hydroxybutyrate
were 91 and 9 mM, respectively, and the corresponding maximum velocities were
430 and 451 mU mg –1 protein. The
Km for NADPH was approximately 10 mM when either of the
acetohydroxy acids was the other substrate. Preparation of the acetohydroxy
acid substrates by hydrolysis of the parent esters in strong base led to the
formation of inhibitory by-products. Racemisation of the acetohydroxy acids
was detected in assay mixtures.
Construction and analysis of a high-CO2-requiring mutant of the cyanobacterium Anabaena sp. strain PCC7120
Authors: Tianfu Wu , Lirong Song , Yongding Liu
Published: September 2002

A mutant of Anabaena sp. strain PCC7120 requiring high
CO2 was generated using Tn5 mutagenesis. This is the
first data for a filamentous cyanobacterium. The mutant was capable of growing
at 5% CO2, but incapable of growing at air levels
of CO2. Southern hybridization analysis indicated that
the Anabaena genome was inserted by the transposon at
one site. The apparent photosynthetic affinity of the mutant to external
dissolved inorganic carbon (DIC) was about 300 times lower that of the wild
type (WT), and the medium alkalization rate as well as the carboxysomal
carbonic anhydrase activity of the mutant was also lower than those of the WT.
When the mutant was transferred from the culture medium bubbled with 5%
CO2 to higher DIC (8.4%
CO2) or 1% CO2, it showed
similar responses to the WT. However, aberrant carboxysomes were found in the
mutant cells through ultrastructural analysis, indicating it was most probably
the wrong organization of the carboxysomes that eventually led to the
inefficient operation of carboxysomal carbonic anhydrase and the subsequent
defectiveness of the mutant in utilizing DIC.
Polo-like kinase expression in normal human endometrium during the menstrual cycle
Authors: Takai Noriyuki , Miyazaki Tami , Miyakawa Isao , Hamanaka Ryoji
Published: September 2002

The enzyme, polo-like kinase (PLK), is a mammalian serine/threonine kinase
involved in cell cycle regulation. A great deal of evidence regarding the role
of PLK in the cell cycle has been obtained through studies of cultured cells,
though little is known about its function or even expression
in vivo. The endometrium undergoes rapid proliferation
and differentiation under ovarian steroid hormone control during the 28-day
cycle. Thus, normal endometrium provides an excellent model in which to study
the hormone dependency of PLK expression. In the present study, we examined
the features of PLK expression in 20 samples of normal human endometrium
during the menstrual cycle. The expression of Ki-67 and proliferating cell
nuclear antigen (PCNA) were also examined as markers of proliferation.
Immunohistochemical studies showed that PLK staining was detected in the
basement membrane of many endometrial glands, stromal cells, and some
endothelial cells. The number of PLK-positive endometrial gland cells was
significantly higher in the late proliferative phase (19.16%
4.98%) and the early secretory phase (19.28% 4.99%) than
in the early proliferative phase (2.60% 2.33%) or the late
secretory phase (5.76% 2.16%)
(P<0.0001). PLK expression seemed to be correlated
with the expression of Ki-67 and PCNA in many endometrial glands and stromal
cells particularly in the late proliferative phase, reflecting a role of PLK
in cellular proliferation. Nevertheless, in the early secretory phase, at
which point the expression of Ki-67 and PCNA decreased in endometrial glands,
PLK was strongly expressed. This finding suggests that PLK may have some
post-mitotic functions in certain specialized cell types. Although the highest
expression of PLK was observed in the late proliferative and the early
secretory phases, the expression drastically decreased in the late secretory
phase. These findings, taken together, indicate that the expression of PLK in
normal endometrium fluctuates over the course of the menstrual cycle,
suggesting in turn that PLK is associated with hormone-dependent cellular
proliferation and that hormone functions may be involved in its regulation.
Intrauterine insemination in sows with reduced sperm number
Authors: Krueger C. , Rath D.
Published: September 2002

Usually 2–3 x 109 sperm per insemination are used
in pigs. In other species it has been shown that changing the site of
insemination allows a reduction in the amount of sperm per insemination dose.
The goal of this study was to determine the minimal number of sperm that can
be used, without a reduction in either the pregnancy rate or the mean litter
size, using surgical deep intrauterine insemination in sows after weaning.
Three different sperm concentrations (5 x 108, 1 x
108 and 1 x 107 sperm cells
extended in 0.5 mL AndrohepTM) were inseminated into the
tip of each uterine horn. In addition two groups of control sows were
inseminated once intracervically 24–32 h after the first signs of
oestrus with 1 x 109 and 3 x 109
sperm in 80 mL AndrohepTM extender. Animals that became
pregnant were allowed to farrow normally. No significant differences were
observed between groups inseminated surgically with the three different sperm
dosages with respect to pregnancy or farrowing rate. There was also no
significant difference between the results of these groups and the results
obtained from the non-surgically inseminated control groups. Neither the mean
number of live-born nor stillborn piglets was significantly different between
the surgically inseminated groups and the control groups. The total number of
piglets born in each group was also not statistically different. The data show
that the sperm number to be used for surgical insemination can be lowered
without loss of the fertilization potential and may be used in the field as
soon as a suitable insemination device is available.
Estrogen sulfamates: a new approach to oral estrogen therapy
Authors: Elger W. , Barth A. , Hedden A. , Reddersen G. , Ritter P. , Schneider B. , Züchner J. , Krahl E. , Müller K. , Oettel M. , Schwarz Sigfrid
Published: September 2002

Sulfamate substitution (-O-SO 2-NH
2) at carbon atom 3 of the steroid skeleton leads to
orally active prodrugs of estrogens with much higher systemic, but lower
hepatic, estrogenic activity than their parent steroids. This dissociation is
achieved by first passage through the liver in erythrocytes, followed by
systemic hydrolysis which releases the ‘parent’ estrogen. In the
rat, orally administered tritiated estradiol sulfamate, unlike estradiol,
appears in the circulation at high concentrations. At C
max , approximately one third of the administered dose
forms a depot in the circulation (98% in erythrocytes,
2% in plasma). Significant estradiol, estrone and estrone sulfate
concentrations were recorded in plasma during depletion of the red blood cell
pool. Estradiol sulfamate (J995) has no estrogen receptor affinity
per se or estrogenic activity
in vitro ( i.e. without hydrolysis). Its oral
uterotropic activity in rats is approximately 100 times greater than that of
estradiol, however, its hepatotropic activity is only marginally elevated.
These functions include bile secretion, the secretion of angiotensinogen,
lipoproteins (total and high-density lipoprotein cholesterol) and insulin-like
growth factor I (IGF-I). Orally administred estradiol sulfamate led to
systemic estrogenic effects without significant hepatic responses, whereas
estradiol and other ‘conventional’ estrogens exerted parallel
systemic and hepatic estrogenic effects. Sulfamate technology represents an
approach to the use of natural estrogens for fertility control and hormone
replacement therapy in both genders. In this context, reduced effects on
hemostatic factors, angiotensinogen, bile and IGF-I secretion seem the most
important aspects. In addition, blood concentrations of estrogens are less
variable than with conventional estrogens.
Regulation of metalloproteinases by nitric oxide in human trophoblast cells in culture
Authors: Novaro Virginia , Colman-Lerner Alejandro , Ortega Felipe Vadillo , Jawerbaum Alicia , Paz Dante , Nostro Fabiana Lo , Pustovrh Carolina , Gimeno Martha F. , González Elida
Published: September 2002

The process of embryo implantation requires extensive remodelling of the
endometrial extracellular matrix, a function largely performed by
matrix-degrading metalloproteinases (MMPs). In the present study, we used
trophoblast cells isolated from human term placentas to study the regulation
of MMPs by nitric oxide (NO). Using a combination of zymography, Western blot
and indirect immunofluorescence, we showed that MMP-2 and MMP-9 are increased
during the conversion from low-motile cytotrophoblast cells to the highly
motile and differentiated syncytiotrophoblast multinucleated cells. We also
observed an increase in NO production and NO synthase (NOS) expression during
this cellular differentiation process. In addition, we demonstrated a positive
regulatory role of NO on the activity and protein expression of MMP-2 and
MMP-9, because NO donors (NOC-18 and spermine-NONOate) or the NOS substrate
(L-arginine) stimulate, whereas NOS inhibitors
(NG-nitro-L-arginine methyl ester
and NG-monomethyl-L-arginine)
reduce the expression and gelatinolytic activity of MMP-2 and MMP-9 in
isolated trophoblast cells. Taken together, these results suggest that, in
differentiating trophoblasts, NO regulates the induction of matrix-degrading
proteases required for invasion during embryo implantation.
Seasonal differences in lamb birthweight do not arise from inherent differences in the oocyte and/or early embryo
Authors: Mitchell L. M. , Silveira M. , Mylne M. J. A. , Matthews K. , Dingwall W. S.
Published: September 2002

The aim of this study was to determine whether previously observed seasonal differences in conceptus development in ewes are attributable to inherent differences in the oocyte and/or early embryo. Day 6 embryos were recovered from 50 ewes subjected to a standard oestrus synchronization, superovulation and laparoscopic artificial insemination protocol during October (peak breeding season) and April (transition to anoestrus). During the following October, 40 grade 1 and 2 embryos from each month, which had been cryopreserved at the late morula or unexpanded blastocyst stage, were thawed and transferred in singleton to synchronous recipients. Resulting pregnancies were monitored to term. For ewes receiving October- and April-produced embryos, overall mean SEM liveweight at the time of embryo transfer was 72 number of corpora lutea on the ovaries was 2.7 pregnant and their gestation lengths were 147 production on peripheral ovine pregnancy-associated glycoprotein concentrations during pregnancy or on fetal and placental characteristics at term, but, for each month, male lambs were heavier than females and were associated with larger placentae. Lamb birthweight was positively correlated with placental weight (r2 = 0.474, P<0.001) and the total weight of cotyledonary tissue (r2 = 0.429, P<0.001), but not to the number of cotyledons. Results demonstrate close relationships between fetal and placental weights at term, and that seasonal effects on conceptus development in ewes do not arise from inherent differences in the oocyte and/or early embryo.
Angiogenesis in the primate ovary
Authors: Fraser Hamish M. , Wulff Christine
Published: September 2002

The ovary is distinctive in undergoing cyclic changes in angiogenesis that
play a critical role in the normal functioning of the female reproductive
system. The current paper describes the use of the marmoset monkey as an
in vivo model in which the cellular and molecular
regulation of angiogenesis in the ovary can be investigated and the effects of
manipulation of angiogenic factors elucidated. The studies are based on
quantifying changes in blood vessel area and endothelial cell proliferation,
monitoring changes in expression patterns of putative angiogenic regulatory
factors and targeting these factors by antagonists
in vivo. Quantification of endothelial cell
proliferation shows that angiogenesis commences in the pre-antral follicle,
increases with follicular development and becomes intense in the early corpus
luteum. Vascular endothelial growth factor (VEGF), a principal angiogenic
factor, is synthesized by the developing follicle and corpus luteum.
Administration of specific antagonists in vivo for
selected periods of the ovulatory cycle shows that inhibition of VEGF results
in a marked decrease in endothelial cell proliferation in the follicle and is
accompanied by a decline in granulosa cell proliferation. Inhibition during
the early or mid-luteal phase results in a marked suppression in luteal
angiogenesis, failure of development of the microvascular tree and suppression
of luteal function. Manipulation of angiogenesis should be a novel approach to
either promoting or inhibiting the normal processes of folliculogenesis,
ovulation and corpus luteum function.
Follicle size and oocyte diameter in relation to developmental competence of buffalo oocytes in vitro
Authors: Raghu H. M. , Nandi S. , Reddy S. M.
Published: September 2002

Follicular size, oocyte morphology and diameter were investigated for their
possible relationship with in vitro developmental
competence of buffalo oocytes. Cumulus oocytes complexes (COCs), aspirated
from small (<3 mm), medium (3–8 mm) and large (>8 mm) follicles of
normal ovaries and cystic ovarian follicles of abattoir-derived ovaries, were
graded for their morphological appearance and were cultured to assess their
developmental competence. The influence of cystic follicles on maturational
competence of COCs recovered from co-existing follicles of cystic ovaries was
studied. The mean diameter of oocytes from follicles of different size were
examined, and the influence of oocyte diameter—(i)
<126 m; (ii) 127–144 m;
(ii) 145–162 m; and (iv)
>163 m—on in vitro maturation, cleavage and
embryo yield was studied. Results suggested that increased fertilization,
cleavage and embryo development were significantly
(P<0.05) higher in COCs aspirated from large
follicles, followed by medium and small-sized normal follicles, and the
presence of cystic follicles had no significant
(P<0.05) effect on the maturation competence of the
COCs recovered from co-existing follicles. The mean diameter of the buffalo
oocyte obtained from normal ovaries was found to be 146.4 m and the rate of
blastocyst production in vitro was significantly higher
(P<0.05) in oocytes with diameters greater than 145
m. In conclusion, the larger the size of the follicles and oocytes, the
greater the developmental competence in vitro of buffalo
oocytes.
Conservation strategies for Africa's large mammals
Authors: Hanks J.
Published: September 2002

Africa’s large mammals are conserved for their aesthetic, scientific and
economic values. Many of these species face a gloomy future precipitated by a
combination of factors directly and indirectly influenced by the activities of
man, including habitat loss, overexploitation, poor management of designated
protected areas, and the vulnerability of small isolated populations.
Africa’s designated protected areas and biodiversity hotspots are also
under threat, highlighting the importance of embracing community participation
to address accelerating poverty and malnutrition. Innovative strategies are
required for the conservation of Africa’s mammals, such as the
integration of a wide range of species in the production landscape, including
the farming community. Transfrontier conservation areas (TFCAs) have been
established with the combined objectives of conserving biodiversity, creating
new jobs in the tourism and wildlife industry, and promoting a culture of
peace. These areas extend far beyond traditional national parks, providing
opportunities for integrating large mammals into sustainable land-use
practices, at the same time as addressing some of the continent’s more
pressing socioeconomic needs. Research on African mammals will inevitably have
to change direction to accommodate the growing threats and changed
circumstances. Priorities will include the identification of corridors
associated with TFCA establishment, the determination of the economic value of
certain species in consumptive use programmes, research on contraception as a
management option in restricted areas, and further work on the indirect use
value of species. There will also be worthwhile opportunities to be pursued
with ex situ conservation programmes, but these need to be focussed more
efficiently.
The road to ovulation: the role of oestrogens
Authors: Findlay J. K. , Britt K. , Kerr J. B. , O'Donnell L. , Jones M. E. , Drummond A. E. , Simpson E. R.
Published: September 2002

Oestrogens have been known for many years to have a direct influence on
folliculogenesis. Oestradiol-17β‚ (E2) and its analogues have both
proliferative and differentiative effects on somatic cells of follicles.
Nevertheless, definitive proof of an obligatory role for oestrogen in
folliculogenesis and elucidation of the mechanisms subserving its different
actions in follicular cells remains elusive. Several recent developments
permit a re-examination of the roles and actions of E2 in the follicle. They
are: (i) the discovery of a second form of the oestrogen
receptor, ERβ; (ii) the advent of genetically
modified mice with deletions in the ERα(αERKO) ERβ‚
BERKO) and the double ER deletions (αβERKO); and
(iii) a mouse model of oestrogen deficiency (ArKO) by
targeted disruption of the cyp
19gene encoding the aromatase enzyme. Recent information
derived from these models is reviewed to re-assess the roles and actions of
oestrogens in follicular dynamics and the phenotypic differentiation of
ovarian somatic cells in the ovary. The data demonstrate that oestrogen is
obligatory for normal folliculogenesis and that the phenotype of the ovarian
somatic cells depends on the steroid milieu. The ArKO mouse provides a model
to test the roles of the respective ERs in proliferation and differentiation
using specific agonists and antagonists, and to study regulation of the
differentiation of ovarian and testicular somatic cells.
The role of 5a-reduction in steroid hormone physiology
Authors: Wilson Jean D.
Published: September 2002

A role for 5α-reduction in androgen physiology was first established
with the recognition that dihydrotestosterone, the 5α-reduced metabolite
of testosterone, is formed in many androgen target tissues, binds to the
androgen receptor with greater affinity than testosterone, and plays an
essential role in virilization of the urogenital sinus and urogenital tubercle
during male development. Two 5α-reductases perform this reaction, and
both isoenzymes utilize NADPH as cofactor and have broad specificity for
steroids containing a Δ4, 3-keto configuration.
5α-Reduction, which is essentially irreversible, flattens the steroid
molecule because of altered relation of the A and B rings, and stabilizes the
hormone–receptor complex. Studies involving
in vitro reporter gene assays and intact mice in which
both isoenzymes are disrupted, indicate that the fundamental effect of
dihydrotestosterone formation is to amplify hormonal signals that can be
mediated by testosterone at higher concentrations. 5α-Reduction also
plays a role in the action of other steroid hormones, including the plant
growth hormone, brassinolide, the boar pheromones, androstanol and
androstenol, progesterone (in some species), and, possibly, aldosterone and
cortisol. The fact that the reaction is important in plants and animals
implies a fundamental role in steroid hormone action.
Australasian marsupials - to cherish and to hold
Authors: Tyndale-Biscoe C. H.
Published: September 2002

Considerable interchange of mammals between South America and Australasia
occurred during the first half of the Tertiary, including the presence of
placental mammals in Australia. This challenges the old assumption that the
marsupial radiation in Australia was made possible by the absence of placental
competition, and suggests that two properties of marsupial organization may
have favoured their survival in the increasingly arid climates that developed
after the separation of Australasia from Antarctica. The basal metabolic rates
of marsupials are about 70% of equivalent placentals, so their
maintenance requirements for energy, nitrogen and water are lower, whereas
their field metabolic rates are about the same, which means that they have a
greater metabolic scope to call on when active. This may have given marsupials
an advantage in semi-arid environments. The lengthy and complex lactation of
marsupials enables the female to exploit limited resources over an extended
period without compromising the survival of the young. Both these properties
of marsupials enabled them to survive the double constraints of low fertility
soils and the uncertain climate of Australia throughout the Tertiary. The
arrival of people was followed first by the extinction of the large marsupials
and, much later, by the wholesale decline or extinction of the small-to-medium
sized species. The common factor in both extinctions may have been the
constraints of marsupial reproduction.
Immunolocalization of sex steroid hormone receptors in the canine uterine tube and their relation to sex steroid hormone levels
Authors: Vermeirsch Hilde , Broeck Wim Van Den , Coryn Mark , Simoens Paul
Published: September 2002

The aim of this immunohistochemical study was to describe the cellular distribution of the estrogen receptor-α (ERα), progesterone receptor (PR) and androgen receptor (AR) in canine uterine tubes. Samples of uterine tubes were taken from dogs in different stages of the estrous cycle, and dogs that were pregnant or had just delivered. Nuclear staining for sex steroid hormone receptors was observed in the surface epithelium, stromal cells and smooth muscle cells of the muscular layer. Only slight differences in staining pattern were observed between the ampulla and fimbriae. The staining for ERα and PR showed changes throughout the estrous cycle. Some of these changes were related to changing concentrations of sex steroid hormones. High staining scores for ERα and PR were found during proestrus and low scores during early metestrus. The staining for AR showed only minor cyclic changes. However, during proestrus and estrus, cytoplasmic staining for AR was observed in differentiated secretory epithelial cells, when nuclear staining in these cells was nearly absent. For the three hormone receptors, stromal cells generally stained with a higher intensity than epithelial cells. It is likely that many steroid hormone actions on the epithelium are mediated through stromal cells. During pregnancy, rather high staining scores were found for ERα and AR in the uterine tube. This is in contrast to observations in the canine pregnant uterus.
From brain determination to testis determination: evolution of the mammalian sex-determining gene
Authors: Graves Jennifer A. Marshall
Published: September 2002

In mammals, sex is determined by an XY male:XX female sex chromosome system in
which a male-dominant gene on the Y chromosome (SRY)
determines testis formation. Sex chromosomes evolved from an ordinary autosome
pair as the Y chromosome was progressively degraded. The Y chromosome has lost
nearly all of its 1500 original genes, and those that survived did so because
they evolved a critical role in male determination or differentiation.
SRY is typical of Y-borne genes. Comparative gene
mapping and sequencing shows that SRY arose quite
recently as a degraded version of the SOX3 gene on the X
chromosome. SOX3 is expressed predominantly in brain,
and so is more likely to be a brain-determining than a testis-determining
gene. The male-dominant action of SRY may be an
illusion, as its structure suggests that it works by interfering with the
action of a related gene, which in turn inhibits testis development. This
hypothesis can give a good account of how a brain-determining gene acquired a
role in testis determination via differential dosage of
SOX3. SRY has no central role in
sex determination and it can be replaced as a trigger and lost, as have many
other Y-borne genes in recent evolutionary history. The absence of
SRY in two species of the mole vole
(Ellobius) suggests that its useful life is already
running out.
In vitro production of pig embryos: a point of view
Authors: Coy Pilar , Romar Raquel
Published: September 2002

Porcine embryos have become raw materials for different programmes of reproductive biotechnology and the in vitro production of embryos has some advantages over in vivo production in gene transfer programmes and for xenotransplantation. Despite this promising future, several problems limit the success of the in vitro production (IVP) of viable porcine embryos. Porcine IVP has not been fully developed because of several problems associated with different techniques, such as incomplete final maturation status after in vitro maturation, a high incidence of polyspermy after in vitro fertilization and a low development rate and poor quality of blastocysts at the end of culture. The results could be improved with studies comparing in vivo and in vitro conditions, standardization of techniques for sperm processing, testing new additives in the culture media and developing intracytoplasmic sperm injection procedures. The first objective of the present article is to summarize the main studies published on the subject. Second, we provide a guide for researchers starting work on the IVP of pig embryos, making special mention of first papers and the most recent achievements for each of the different techniques. Third, we provide suggestions for future experiments designed to improve the results of each technique.
Angiotensin II increases intracellular calcium concentration in pig endometrial stromal cells through type 1 angiotensin receptors, but does not stimulate phospholipase C activity or prostaglandin F2α secretion
Authors: Simasko Steven M. , Braileanu Gheorghe T. , Speth Robert C. , Mirando Mark A. , Daubert Daisy , Hu Jianbo
Published: September 2002

Although the presence of endometrial receptors for angiotensin (Ang) II has been demonstrated, a specific function for AngII in the uterus has not been identified. Cytosolic free Ca2+ concentration [Ca2+]i, phospholipase C (PLC) activity and prostaglandin (PG) F2α secretion in response to AngII and oxytocin (OT) were measured in pig endometrial stromal cells collected 16 days after oestrus. Treatment with 100 nm OT or AngII increased (P<0.001) [Ca2+]i in stromal cells similarly (720 v. 690 m, respectively). Subsequent administration of OT or AngII to the same cells induced smaller [Ca2+]i increases (25% or 35% of the initial responses, respectively) that occurred only if the second exposure to the same agent took place at least 5 min after the first. When administered sequentially, OT and AngII each induced a full response within 1 min of the previous treatment, regardless of which peptide was applied first. Whereas OT increased PLC activity and PGF2α secretion in stromal cells (P<0.01), AngII did not increase either PLC activity or PGF2α secretion. Type 1 AngII (AT1) receptors were present on stromal cells, whereas AT2 receptors were absent. Therefore, the effect of AngII in stromal cells was mediated via AT1 receptors. That AngII increased [Ca2+]i in stromal cells, but did not increase PLC or PGF2α secretion, indicates that either AngII releases a pool of Ca2+ through a mechanism that is not mediated by PLC and is not involved in PGF2α secretion or that a mechanism for PGF2α production other than one involving Ca2+ may exist.
Comparison of gene expression at the fetomaternal interface between normal and recurrent pregnancy loss patients
Authors: Baek Kwang-Hyun , Choi Bum Chae , Lee Jin-Hie , Choi Hee-Kyung , Lee Sook-Hwan , Kim Jung-Wook , Hill Joseph A. , Chung Hyung-Min , Ko Jung Jae , Cha Kwang Yul
Published: September 2002

—Normal pregnancy requires a series of immunological, metabolic, vascular and endocrine regulating processes. However, the specific genes and proteins involved in these processes are not well defined. Aberration of these processes may lead to problems in pregnancy. One of these problems may be recurrent pregnancy loss (RPL). Little information is available on the level of expression of genes that may play a role in normal pregnancy. Therefore, this study determined whether different levels of gene expression at the feto-maternal interface could be associated with factors for RPL. The expression patterns of genes isolated from subtractive hybridization analysis performed with chorionic villi from normal and abnormal pregnancies were investigated. Eight genes classified into groups, including immunosuppression-related, embryo attachment-related and angiogenesis-related, were isolated.
Non-invasive monitoring of reproductive status in wild mongoose lemurs (Eulemur mongoz)
Authors: Curtis Deborah J. , Zaramody Alphonse , Green Daphne I. , Pickard Amanda R.
Published: September 2002

Endocrine profiles were investigated in wild and captive mongoose lemurs
(Eulemur mongoz; Lemuridae) by analysing faecal
progestagens and oestrogens. Oestrous cycle characterization was not possible,
as most females appeared to conceive during the first oestrus of the breeding
season. Conception was preceded by a pseudo-oestrus with no discernible luteal
phase. Pseudo-oestrus and oestrus identification was possible by investigating
the oestrogen : progestagen ratio. Pregnancy was reliably determined
approximately 47 days after conception, when progestagen and oestrogen
excretion increased above breeding season concentrations. Gestation was
further characterized by high progestagen concentrations and a decline in
oestrogen excretion 70–80 days after conception. Post partum,
progestagens declined, but oestrogen excretion increased to exceed breeding
season concentrations. In the wild group, a nulliparous daughter conceived
while still a member of her natal group and aborted after 70–80 days of
pregnancy at which time progestagens had declined but oestrogens remained
high. Comparisons with other strepsirhine primates suggest that pseudo-oestrus
followed by conception at first oestrus may be prevalent in lemurs.
Gestational progesterone profiles vary between species, but a delayed increase
in oestrogens during pregnancy could be common to all strepsirhines, although
oestrogen levels during the final trimester of pregnancy differ between lemurs
and lorises. Methodological investigations showed that prolonged storage of
faeces in ethanol is viable and that the presence of undigested vegetable
matter in the faecal pellets had no effect on the interpretation of hormone
profiles.
Ceratocystis moniliformopsis sp. nov., an early coloniser of Eucalyptus obliqua logs in Tasmania, Australia
Authors: Yuan Zi-Qing , Mohammed Caroline
Published: September 2002

A new species of Ceratocystis with a
Chalara anamorph was observed to cause black stains on
the cut surfaces of recently felled Eucalyptus obliqua
logs in south-western Tasmania, Australia. It is described as
C. moniliformopsis because of its similarity to
C. moniliformis in morphology of ascospores and
perithecia. This is a homothallic species and is characterised by a thick
perithecial peridium, ovoid perithecia and disciform-based perithecial necks
with convergent ostiolar hyphae. The perithecia are covered with the following
two types of ornamenting hyphae: hyaline, thin-walled, aseptate, tubular hairs
and dark brown, thick-walled, ampliform to conical setae. Its
Chalara anamorph has the following two types of
conidiogenous cells: hyaline, cylindrical tapering phialides and pigmented,
cupulate or divergent phialides with percurrent proliferation. The latter is a
unique type of conidiogenous cell that has not been observed in this genus
before the present study.
A revision of Pultenaea (Fabaceae). 1. Species with ovaries glabrous and/or with tufted hairs
Authors: de Kok R. P. J. , West J. G.
Published: September 2002

All 21 species of the genus Pultenaea Sm. with glabrous
and/or apically tufted ovaries are revised and 17 names are reduced to
synonymy for the first time. The following three new species are described:
Pultenaea alea de Kok,
Pultenaea maritima de Kok and
Pultenaea rostrata de Kok. Three species
(P. glabra, P. humilis and
P. subspicata) are lectotypified and a key to the group
is provided. A brief discussion is given as to the legitimacy of these species
being treated as a separate group. The importance of the ovary indumentum
character and its character states and the various forms of the bracteole are
briefly discussed.
A new rare species of Acacia from north-east Victoria
Authors: Bartolome Marisa , Walsh Neville G. , James Elizabeth A. , Ladiges Pauline Y.
Published: September 2002

A new, rare wattle, Acacia daviesii sp. nov., known from only 10 populations discovered in mountainous, subalpine habitat in north-eastern Victoria, is described and illustrated. A comparative morphological study was undertaken, based on phyllode characters measured from all 10 known populations and herbarium specimens of the five most similar Acacia species: A. acinacea, A. aspera, A. glandulicarpa, A. gunnii and A. paradoxa. The new species has a pendulous habit and resinous phyllodes covered by stalked multicellular glands. Acacia daviesii forms clones by root suckering and seed set appears to be rare. Isozyme analysis based on nine enzyme systems showed that plants within any single population are genetically identical. Variation was detected between all but two populations with only nine known genotypes in an area of 12 km2.