Shifts in thermoregulatory patterns with pregnancy in the poikilothermic mammal—The naked mole-rat (Heterocephalus glaber)

1. 1. The naked mole-rat (Heterocephalus glaber) is a poikilothermic mammal. During gestation metabolic shifts that differ from both mammalian and reptilian thermoregulatory patterns occurred.

2. 2. Body temperature was directly dependent on ambient temperature. At low ambient temperatures the temperature differential (T_b − T_a) was approximately 3°C, whereas at higher ambient temperatures the temperature differential diminished.

3. 3. In early pregnancy (prior to week 3) oxygen consumption at low ambient temperatures was greater than that of non-reproductive animals. A maximal metabolic rate (3.2 ± 1.0 ml O₂ . g⁻¹ . h⁻¹) occurred at an ambient temperature of 27°C. Thereafter the endothermic pattern of metabolism with increasing ambient temperatures was evident. Oxygen consumption decreased with increasing ambient temperature to minimal rates of 1.2 ± 0.1 ml O₂ . g⁻¹ . h⁻¹ over the ambient temperature range of 31–34°C.

4. 4. Oxygen consumption in late pregnancy (1.8 ± 0.1 ml O₂ . g⁻¹ . h⁻¹) was not correlated with ambient temperature over the entire ambient temperature range measured (24–36°C).

5. 5. Differences in thermoregulation in early and late pregnancy may be attributed to different rates of heat loss as a consequence of (a) changes in surface area and body mass or (b) vascular changes. Furthermore the thermoregulatory changes in late pregnancy may indicate that maximal overall metabolic capacity had been reached, for peak resting metabolism (expressed per animal rather than per gram body mass) in early pregnancy was similar to observed metabolism in late pregnancy.

6. 6. The dissociation of metabolism from both ambient temperature and body temperature in late pregnancy could confer an energetic advantage to this arid dwelling underground inhabitant; for it may enable the breeding female to partition a greater portion of available energy into reproduction.

Reproduction Is Associated with a Tissue-Dependent Reduction of Oxidative Stress in Eusocial Female Damaraland Mole-Rats (Fukomys damarensis)

Oxidative stress has been implicated as both a physiological cost of reproduction and a driving force on an animal''s lifespan. Since increased reproductive effort is generally linked with a reduction in survival, it has been proposed that oxidative stress may influence this relationship. Support for this hypothesis is inconsistent, but this may, in part, be due to the type of tissues that have been analyzed. In Damaraland mole-rats the sole reproducing female in the colony is also the longest lived. Therefore, if oxidative stress does impact the trade-off between reproduction and survival in general, this species may possess some form of enhanced defense. We assessed this relationship by comparing markers of oxidative damage (malondialdehyde, MDA; protein carbonyls, PC) and antioxidants (total antioxidant capacity, TAC; superoxide dismutase, SOD) in various tissues including plasma, erythrocytes, heart, liver, kidney and skeletal muscle between wild-caught reproductive and non-reproductive female Damaraland mole-rats. Reproductive females exhibited significantly lower levels of PC across all tissues, and lower levels of MDA in heart, kidney and liver relative to non-reproductive females. Levels of TAC and SOD did not differ significantly according to reproductive state. The reduction in oxidative damage in breeding females may be attributable to the unusual social structure of this species, as similar relationships have been observed between reproductive and non-reproductive eusocial insects.     

Colony and nest site fidelity of the rock shag ( Phalacrocorax magellanicus )

The rock shag (Phalacrocorax magellanicus) is an endemic species from southern Argentina and Chile. In Argentina, the population is distributed along the Patagonian coast in 143 small colonies (5–377 pairs). We studied colony and nest site fidelity of rock shags at Punta Loma, Patagonia, Argentina. We banded 37 adults from December 2001 to June 2003, during two breeding and two non-breeding seasons. Nest site fidelity was extremely high during consecutive breeding and also non-breeding seasons. The high percentage of banded birds residing in the colony in consecutive seasons suggests that rock shags are highly faithful to breeding sites and supports the idea of low post-breeding dispersion.     

Female Corncrake(Crex crex) singing in the wild

Summary The male Corncrake (Crex crex) has a characteristic mating call. In aviary it has been shown that females can also produce a call similar to the male's typical crex crex. I describe a strikingly different call produced by a female on Öland, southeast Sweden. The sex identification was based on the small size during close examination in the hand. The female call has a similar rhythm to the male call but lacks the rasping of the male and is almost a barking sound. The female was heard calling continuously at night throughout a three-week-period. Another bird producing the same call was heard about 100 m from the caught female suggesting two females in the same field. No male Corncrakes were heard in the field during the period when the female was calling. Possible explanations for this behaviour and the function of the call is discussed.

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Rufe eines weiblichen Wachtelkönigs(Crex crex) im Freiland

Zusammenfassung Männliche Wachtelkönige (Crex crex) haben charakteristische Balzrufe. In Gefangenschaft gehaltene weibliche Wachtelkönige rufen ebenfalls männchenähnlich crex crex. Dieser Artikel beschreibt einen bisher unbekannten Ruf eines weiblichen Wachtelkönigs von der Insel Öland/SE Schweden. Die Geschlechtsbestimmung erfolgte aufgrund der geringen Maße. Die Rufe des Weibchens zeigten einen ähnlichen Rhythmus wie die der Männchen, ihnen fehlt jedoch der knarrende Klang und sie klingen eher bellend. Das rufende Weibchen wurde über drei Wochen regelmäßig nachts gehört. Ein weiterer Vogel mit den gleichen Rufen wurde etwa 100 Meter neben dem gefangenen Weibchen gehört, was darauf deutet, daß es sich um zwei Weibchen in dem gleichen Feld gehandelt hat. Rufende Männchen wurden während dieser Zeit nicht gehört. Die Bedeutung dieser Weibchen-Rufe wird diskutiert.

     

Functional Morphology of the Olfactory Mucosa and Olfactory Bulb in Fossorial Rodents: The East African Root Rat (Tachyoryctes splendens) and the Naked Mole Rat (Heterocephalus glaber)

Optimal functioning of the olfactory system is critical for survival of fossorial rodents in their subterranean lifestyle. This study examines the structure of the olfactory mucosa and olfactory bulb of two fossorial rodents exhibiting distinct social behaviors, the East African root rat and the naked mole rat. The social naked mole rat displayed simpler ethmoturbinates consisting of dorsomedial and broad discoid/flaplike parts that projected rostrally from the ethmoid bone. In the solitary root rat however, the ethmoturbinates were highly complex and exhibited elaborate branching which greatly increased the olfactory surface area. In addition, when correlated with the whole brain, the volume of the olfactory bulbs was greater in the root rat (4.24 × 10^?2) than in the naked mole rat (3.92 × 10^?2). Results of this study suggest that the olfactory system of the root rat is better specialized than that of the naked mole rat indicating a higher level of dependence on this system since it leads a solitary life. The naked mole rat to the contrary may have compensated for its relatively inferior olfactory system by living in groups in a social system. These findings demonstrate that structure of the olfactory system of fossorial mammals is dictated by both behavior and habitat.     

A review of the systematics of the sleeper shark genus Somniosus with redescriptions of Somniosus ( Somniosus) antarcticus and Somniosus ( Rhinoscymnus) longus (Squaliformes: Somniosidae)

Past treatments of the sleeper shark genus Somniosus generally recognize three species: S. microcephalus, S. pacificus, and S. rostratus. Based on morphometrics and meristics, we conclude that this genus includes two subgenera (Somniosus and Rhinoscymnus) and five species. Subgenus Somniosus differs from Rhinoscymnus by being much larger when adult and in having more numerous tooth rows in the lower jaw, hooklike rather than leaf-shaped dermal denticles, more numerous spiral valve and vertebral counts, and a poorly calcified vertebral column. Subgenus Somniosus includes S. (Somniosus) microcephalus and S. (S.) pacificus of the Northern Hemisphere and S. (S.) antarcticus of the Southern Hemisphere. Although Somniosus antarcticus has been synonymized with S. microcephalus and identified as S. pacificus in past literature, it differs from S. microcephalus in having a shorter interdorsal space, a more posterior first dorsal fin, lower dorsal fins, more numerous tooth rows in the lower jaw, more numerous spiral valve counts, and fewer precaudal vertebrae. Somniosus antarcticus also differs from S. pacificus by having a shorter prebranchial length, lower dorsal fins, more numerous spiral valve counts, and slightly more precaudal vertebrae. Subgenus Rhinoscymnus includes S. (Rhinoscymnus) rostratus from the eastern North Atlantic and Mediterranean Sea (senior synonym of S. bauchotae) and S. (R.) longus from the western Pacific Ocean. Somniosus longus has been synonymized with S. rostratus, but differs in having a relatively longer second dorsal fin, a slightly larger eye, more lower tooth rows, and slightly higher spiral valve counts. Both Somniosus (Somniosus) antarcticus and S. (Rhinoscymnus) longus from the Pacific Ocean were redescribed. A key to the species and the geographical distribution of all species are provided.     

Direct and negative regulation of the sycO-ypkA-ypoJ operon by cyclic AMP receptor protein (CRP) in Yersinia pestis

Background  

Pathogenic yersiniae, including Y. pestis, share a type III secretion system (T3SS) that is composed of a secretion machinery, a set of translocation proteins, a control system, and six Yop effector proteins including YpkA and YopJ. The cyclic AMP receptor protein (CRP), a global regulator, was recently found to regulate the laterally acquired genes (pla and pst) in Y. pestis. The regulation of T3SS components by CRP is unknown.     

Suppression of the lexC (ssbA) mutation of Escherichia coli by a mutant of bacteriophage P1

Summary A new mutant of bacteriophage P1 designated lxc that suppresses the phenotype of lexC and ssbA mutants of Escherichia coli was isolated and characterized. The properties of lexC mutants suppressed by the lxc mutation include temperature sensitive growth at 42° C, sensitivity to ultraviolet light and alkylating agents, and a nonmutagenic response following exposure to ultraviolet irradiation. A bac mutant of bacteriophage P1 that suppresses the temperature sensitivity of dnaB mutants does not affect the phenotype of lexC or ssbA mutants. Neither the lxc or bac mutations affect the ultraviolet light sensitivity of strains with the mutations uvrA155, lexA102, or recA56.     

Ovulation and implantation in montane voles (Microtus montanus) as a function of varying amounts of copulatory stimulation

Estrous female voles (Microtus montanus) received (a) no copulation, (b) one ejaculatory series, (c) two ejaculatory series, or (d) more than two series. Copulation was shown to be essential for ovulation, and increasing amounts of copulatory stimulation were demonstrated to increase the probability of ovulation. Only 25% of females receiving one ejaculatory series ovulated, whereas 100% of those receiving more than two series ovulated. Thus, multiple ejaculations play an important role in successful reproduction in this species.     

Phylogeny of Salmonine Fishes Based on Growth Hormone Introns: Atlantic (Salmo) and Pacific (Oncorhynchus) Salmon Are Not Sister Taxa

Though salmonid fishes are a well-studied group, phylogenetic questions remain, especially with respect to genus-level relationships. These questions were addressed with duplicate growth hormone (GH) introns. Intron sequences from each duplicate gene yielded phylogenetic trees that were not significantly different from each other in topology. Statistical tests supported validity of the controversial monotypic genusParahucho,monophyly ofOncorhynchus,and inclusion ofAcantholingua ohridanawithinSalmo.Suprisingly, GH1 intron C (GH1C) did not support the widely accepted hypothesis thatOncorhynchus(Pacific salmon and trout) andSalmo(Atlantic salmon and trout) are sibling genera; GH2C was ambiguous at this node. Previously published data were also examined for support ofSalmoandOncorhynchusas sister taxa and only morphology showed significant support. If not sister taxa, the independent evolution of anadromy—the migration to sea and return to freshwater for spawning—is most parsimonious. While there was incongruence with and among published data sets, the GH1C intron phylogeny was the best hypothesis, based on currently available molecular data.     

Cleavage and gastrulation in the shrimp Penaeus (Litopenaeus) vannamei (Malacostraca, Decapoda, Dendrobranchiata)

While most malacostracan crustaceans develop through superficial cleavage, in the Amphipoda, Euphausiacea, and Dendrobranchiata (Decapoda) cleavage is complete. Euphausiaceans and dendrobranchiate shrimp share a similar early cleavage pattern, early cleavage arrest and ingression of mesendoderm progenitor cells, a ring of crown cells (prospective naupliar mesoderm) around the blastopore, and hatching as a nauplius larva. Yet recent phylogenies do not support a close relationship between Euphausiacea and Decapoda. In addition, some variation is reported in the timing of mesendoderm cell arrest and number of crown cells for a number of dendrobranchiates. To determine the representative pattern of development in the Dendrobranchiata, embryos of the Pacific white shrimp Penaeus (Litopenaeus) vannamei were stained with Sytox Green to label chromosomes and nuclei and examined with confocal microscopy. The early cleavage pattern, mesendoblast arrest and subsequent ingression at the 32-cell stage, presence of 8 initial crown cells, and fates of the mesendoblasts are the same for P. vannamei (family Peneaeidae) and Sicyonia ingentis (family Sicyoniidae). The lineage of the primordial endoderm cells differs from that reported for P. kerathurus. These characters were discussed in the context of the evolution of development in the Dendrobranchiata and in comparison to the Euphausiacea.     

Inoculation of coffee plants with the fungal entomopathogen Beauveria bassiana (Ascomycota: Hypocreales)

The entomopathogenic fungus Beauveria bassiana was established in coffee seedlings after fungal spore suspensions were applied as foliar sprays, stem injections, or soil drenches. Direct injection yielded the highest post-inoculation recovery of endophytic B. bassiana. Establishment, based on percent recovery of B. bassiana, decreased as time post-inoculation increased in all treatments. Several other endophytes were isolated from the seedlings and could have negatively influenced establishment of B. bassiana. The recovery of B. bassiana from sites distant from the point of inoculation indicates that the fungus has the potential to move throughout the plant.     

Molecular phylogeny and evolution of the genus Neoerysiphe (Erysiphaceae, Ascomycota)

The genus Neoerysiphe belongs to the tribe Golovinomyceteae of the Erysiphaceae together with the genera Arthrocladiella and Golovinomyces. This is a relatively small genus, comprising only six species, and having ca 300 species from six plant families as hosts. To investigate the molecular phylogeny and evolution of the genus, we determined the nucleotide sequences of the rDNA ITS regions and the divergent domains D1 and D2 of the 28S rDNA. The 30 ITS sequences from Neoerysiphe are divided into three monophyletic groups that are represented by their host families. Groups 1 and 3 consist of N. galeopsidis from Lamiaceae and N. galii from Rubiaceae, respectively, and the genetic diversity within each group is extremely low. Group 2 is represented by N. cumminsiana from Asteraceae. This group also includes Oidium baccharidis, O. maquii, and Oidium spp. from Galinsoga (Asteraceae) and Aloysia (Verbenaceae), and is further divided into four subgroups. N. galeopsidis is distributed worldwide, but is especially common in western Eurasia from Central Asia to Europe. N. galii is also common in western Eurasia. In contrast, the specimens of group 2 were all collected in the New World, except for one specimen that was collected in Japan; this may indicate a close relationship of group 2 with the New World. Molecular clock calibration demonstrated that Neoerysiphe split from other genera of the Erysiphaceae ca 35–45 M years ago (Mya), and that the three groups of Neoerysiphe diverged between 10 and 15 Mya, in the Miocene. Aloysia citriodora is a new host for the Erysiphaceae and the fungus on this plant is described as O. aloysiae sp. nov.     

Volatile and Contact Chemicals Released by Nezara viridula (Heteroptera:Pentatomidae) Have a Kairomonal Effect on the Egg Parasitoid Trissolcus basalis (Hymenoptera: Scelionidae)

The responses of females of the egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) to volatile and contact chemicals from its host Nezara viridula (L.) (Heteroptera: Pentatomidae) were investigated in a Y-tube olfactometer and under open arena conditions. In the Y-tube tests, volatiles from virgin males and from females in a preovipositional state attracted T. basalis females, while volatiles from host virgin females did not. In an open arena, traces left by N. viridula adults in different physiological conditions function as contact cues inducing the wasps to remain longer in the arena and to change the pattern of their walking behavior. However, only contact kairomones from N. viridula mated females in a preovipositional condition induced an arrestment response characterized by an increase in patch searching time and turning rates and a reduction in linear speed. The chemical ecological implications of these results on this host–parasitoid association are discussed.     

A Novel Putative Transporter Maps to the Osteosclerosis (oc) Mutation and Is Not Expressed in theocMutant Mouse

The phenotype of mice homozygous for the osteosclerosis (oc) mutation includes osteopetrosis, and a variety of studies demonstrate that osteoclasts in these mice are present but nonfunctional. We have identified a novel gene that has homology to a family of 12-transmembrane domain proteins with transport functions and maps to proximal mouse chromosome 19, in a region to which theocmutation has been previously assigned. The putative transporter is abundant in normal kidney, but its expression is markedly reduced in kidneys fromoc/ocmice when tested using Northern and Western analyses. Southern analysis of this gene, which we callRoct(reduced inoctransporter), demonstrates that it is intact and unrearranged inoc/ocmice.In situstudies show thatRoctis expressed in developing bone. We propose that the absence ofRoctexpression results in an osteopetrosis phenotype in mice.     

Polymorphism of the S -locus glycoprotein gene ( SLG ) and the S -locus related gene ( SLR1 ) in Raphanus sativus L. and self-incompatible ornamental plants in the Brassicaceae

The S-locus glycoprotein gene, SLG, which participates in the pollen-stigma interaction of self-incompatibility, and its unlinked homologue, SLR1, were analyzed in Raphanus sativus and three self-incompatible ornamental plants in the Brassicaceae. Among twenty-nine inbred lines of R. sativus, eighteen S haplotypes were identified on the basis of DNA polymorphisms detected by genomic Southern analysis using Brassica SLG probes. DNA fragments of SLG alleles specifically amplified from eight S haplotypes by PCR with class I SLG-specific primers showed different profiles following polyacrylamide gel electrophoresis, after digestion with a restriction endonuclease. The nucleotide sequences of the DNA fragments of these eight R. sativus SLG alleles were determined. Degrees of similarity of the nucleotide sequences to a Brassica SLG (S  ⁶ SLG) ranged from 85.6% to 91.9%. Amino acid sequences deduced from these had the twelve conserved cysteine residues and the three hypervariable regions characteristic of Brassica SLGs. Phylogenetic analysis of the SLG sequences from Raphanus and Brassica revealed that the Raphanus SLGs did not form an independent cluster, but were dispersed in the tree, clustering together with Brassica SLGs. These results suggest that diversification of the SLG alleles of Raphanus and Brassica occurred before differentiation of these genera. Although SLR1 sequences from Orychophragmus violaceus were shown to be relatively closely related to Brassica and Raphanus SLR1 sequences, DNA fragments that are highly homologous to the Brassica SLG were not detected in this species. Two other ornamental plants in the Brassicaceae, which are related more distantly to Brassica than Orychophragmus, also lacked sequences highly homologous to Brassica SLG genes. The evolution of self-incompatibility in the Brassicaceae is discussed. Received: 9 October 1997 / Accepted: 27 January 1998     

Molecular phylogeny of the Acre clade (Crassulaceae): Dealing with the lack of definitions for Echeveria and Sedum

The phylogenetic relationships within many clades of the Crassulaceae are still uncertain, therefore in this study attention was focused on the “Acre clade”, a group comprised of approximately 526 species in eight genera that include many Asian and Mediterranean species of Sedum and the majority of the American genera (Echeveria, Graptopetalum, Lenophyllum, Pachyphytum, Villadia, and Thompsonella). Parsimony and Bayesian analyses were conducted with 133 species based on nuclear (ETS, ITS) and chloroplast DNA regions (rpS16, matK). Our analyses retrieved four major clades within the Acre clade. Two of these were in a grade and corresponded to Asian species of Sedum, the rest corresponded to a European–Macaronesian group and to an American group. The American group included all taxa that were formerly placed in the Echeverioideae and the majority of the American Sedoideae. Our analyses support the monophyly of three genera – Lenophyllum, Thompsonella, and Pachyphytum; however, the relationships among Echeveria, Sedum and the various segregates of Sedum are largely unresolved. Our analyses represents the first broad phylogenetic framework for Acre clade, but further studies are necessary on the groups poorly represented here, such as the European and Asian species of Sedum and the Central and South American species of Echeveria.