Biogeography and ecological setting of Indian Ocean hydrothermal vents

Within the endemic invertebrate faunas of hydrothermal vents, five biogeographic provinces are recognized. Invertebrates at two Indian Ocean vent fields (Kairei and Edmond) belong to a sixth province, despite ecological settings and invertebrate-bacterial symbioses similar to those of both western Pacific and Atlantic vents. Most organisms found at these Indian Ocean vent fields have evolutionary affinities with western Pacific vent faunas, but a shrimp that ecologically dominates Indian Ocean vents closely resembles its Mid-Atlantic counterpart. These findings contribute to a global assessment of the biogeography of chemosynthetic faunas and indicate that the Indian Ocean vent community follows asymmetric assembly rules biased toward Pacific evolutionary alliances.     

Bmp4 and morphological variation of beaks in Darwin's finches

Darwin's finches are a classic example of species diversification by natural selection. Their impressive variation in beak morphology is associated with the exploitation of a variety of ecological niches, but its developmental basis is unknown. We performed a comparative analysis of expression patterns of various growth factors in species comprising the genus Geospiza. We found that expression of Bmp4 in the mesenchyme of the upper beaks strongly correlated with deep and broad beak morphology. When misexpressed in chicken embryos, Bmp4 caused morphological transformations paralleling the beak morphology of the large ground finch G. magnirostris.     

A case of antibacterial‐responsive mucocutaneous disease in a seven‐year‐old dwarf lop rabbit (Oryctolagus cuniculus) resembling mucocutaneous pyoderma of dogs

A seven‐year‐old, ovariohysterectomised female dwarf lop rabbit (Oryctolagus cuniculus) was referred with severe swelling and erythema of the mucocutaneous junctions of the lips, nares and vulva. Bilateral, severe periocular dermatitis was also present. Heavy pure growths of a member of the Staphylococcus intermedius group were cultured from nasal and aural swabs and skin biopsies. Other possible differential diagnoses were eliminated by standard tests. The clinical features and histopathological characteristics of the biopsies were most consistent with mucocutaneous pyoderma, a dermatosis previously reported in dogs but not in rabbits. Treatment of the bacterial infection with oral marbofloxacin and topical ofloxacin eye drops together with supportive therapy resulted in resolution of the lesions. To the authors’ knowledge, this is the first report of mucocutaneous bacterial pyoderma, similar to mucocutaneous pyoderma of dogs, in a rabbit.     

Harvest interval affects lucerne (Medicago sativa L.) taproot total yield,starch, nitrogen and water-soluble carbohydrates

Lucerne (Medicago sativa L.) has a large taproot to store and release starch, carbohydrates and nutrients during the plant's growth. Recommended management of the lucerne crop aims to keep the taproot stable subject to the demands for feed provision and stand longevity. Field experiments were conducted in Victoria, Australia, to examine the effects of recovery period on taproot mass and nutritive status. Both experiments used established SARDI Seven lucerne crops and were either cut every 21 days (short recovery SR) or every 42 days (long recovery LR). At each defoliation, taproots were extracted for determination of DM yield and starch, water-soluble carbohydrate (WSC) and nitrogen (N) concentration and DM yield. At both sites, WSC and N DM yields along with total taproot DM yield did not change greatly as the experiment progressed. Starch was responsive to herbage accumulation with both concentration and DM yield, increasing when herbage accumulation rates were high and decreasing when herbage accumulation rates were low. At both sites, LR taproots had starch levels equal to or higher than those of SR taproots. We conclude that short intervals between defoliations disrupt the energy cycling between shoots and roots. This is likely to reduce lucerne productivity, particularly during periods of rapid growth.     

Hard choices: Making trade-offs between biodiversity conservation and human well-being

Win–win solutions that both conserve biodiversity and promote human well-being are difficult to realize. Trade-offs and the hard choices they entail are the norm. Since 2008, the Advancing Conservation in a Social Context (ACSC) research initiative has been investigating the complex trade-offs that exist between human well-being and biodiversity conservation goals, and between conservation and other economic, political and social agendas across multiple scales. Resolving trade-offs is difficult because social problems – of which conservation is one – can be perceived and understood in a variety of disparate ways, influenced (in part at least) by how people are raised and educated, their life experiences, and the options they have faced. Pre-existing assumptions about the “right” approach to conservation often obscure important differences in both power and understanding, and can limit the success of policy and programmatic interventions. The new conservation debate challenges conservationists to be explicit about losses, costs, and hard choices so they can be openly discussed and honestly negotiated. Not to do so can lead to unrealized expectations, and ultimately to unresolved conflict. This paper explores the background and limitations of win–win approaches to conservation and human well-being, discusses the prospect of approaching conservation challenges in terms of trade-offs and hard choices, and presents a set of guiding principles that can serve to orient strategic analysis and communication regarding trade-offs.     

The effect of ketamine on the MACBAR of sevoflurane in dogs

ObjectiveTo determine the effect of intravenous ketamine on the minimum alveolar concentration of sevoflurane needed to block autonomic response (MAC_BAR) to a noxious stimulus in dogs.Study designRandomized, crossover, prospective design.AnimalsEight, healthy, adult male, mixed-breed dogs, weighing 11.2–16.1 kg.MethodsDogs were anesthetized with sevoflurane on two occasions, 1 week apart, and baseline MAC_BAR (B-MAC_BAR) was determined on each occasion. MAC_BAR was defined as the mean of the end-tidal sevoflurane concentrations that prevented and allowed an increase (≥15%) in heart rate or invasive mean arterial pressure in response to a noxious electrical stimulus (50 V, 50 Hz, 10 ms). Dogs then randomly received either a low-dose (LDS) or high-dose series (HDS) of ketamine, and treatment MAC_BAR (T-MAC_BAR) was determined. The LDS had an initial loading dose (LD) of 0.5 mg kg^?1 and constant rate infusion (CRI) at 6.25 μg kg^?1 minute^?1, followed, after T-MAC_BAR determination, by a second LD (1 mg kg^?1) and CRI (12.5 μg kg^?1 minute^?1). The HDS had an initial LD (2 mg kg^?1) and CRI (25 μg kg^?1 minute^?1) followed by a second LD (3 mg kg^?1) and CRI (50 μg kg^?1 minute^?1). Data were analyzed with a mixed-model anova and are presented as LSM ± SEM.ResultsThe B-MAC_BAR was not significantly different between treatments. Ketamine at 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, and the maximal decrease (22%) occurred at 12.5 μg kg^?1 minute^?1. The percentage change in MAC_BAR was not correlated with either the log plasma ketamine or norketamine concentration.Conclusions and clinical relevanceKetamine at clinically relevant doses of 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, although the reduction was neither dose-dependent nor linear.     

Evidence for karyogamy and exchange of genetic material in the binucleate intestinal parasite Giardia intestinalis

The diplomonad parasite Giardia intestinalis contains two functionally equivalent nuclei that are inherited independently during mitosis. Although presumed to be asexual, Giardia has low levels of allelic heterozygosity, indicating that the two nuclear genomes may exchange genetic material. Fluorescence in situ hybridization performed with probes to an episomal plasmid suggests that plasmids are transferred between nuclei in the cyst, and transmission electron micrographs demonstrate fusion between cyst nuclei. Green fluorescent protein fusions of giardial homologs of meiosis-specific genes localized to the nuclei of cysts, but not the vegetative trophozoite. These data suggest that the fusion of nuclei, or karyogamy, and subsequently somatic homologous recombination facilitated by the meiosis gene homologs, occur in the giardial cyst.     

Twenty-five essential research questions to inform the protection and restoration of freshwater biodiversity

1. Freshwater biodiversity is declining at an unprecedented rate. Freshwater conservationists and environmental managers have enough evidence to demonstrate that action must not be delayed but have insufficient evidence to identify those actions that will be most effective in reversing the current trend.
2. Here, the focus is on identifying essential research topics that, if addressed, will contribute directly to restoring freshwater biodiversity through supporting ‘bending the curve’ actions (i.e. those actions leading to the recovery of freshwater biodiversity, not simply deceleration of the current downward trend).
3. The global freshwater research and management community was asked to identify unanswered research questions that could address knowledge gaps and barriers associated with ‘bending the curve’ actions. The resulting list was refined into six themes and 25 questions.
4. Although context-dependent and potentially limited in global reach, six overarching themes were identified: (i) learning from successes and failures; (ii) improving current practices; (iii) balancing resource needs; (iv) rethinking built environments; (v) reforming policy and investments; and (vi) enabling transformative change.
5. Bold, efficient, science-based actions are necessary to reverse biodiversity loss. We believe that conservation actions will be most effective when supported by sound evidence, and that research and action must complement one another. These questions are intended to guide global freshwater researchers and conservation practitioners, identify key projects and signal research needs to funders and governments. Our questions can act as springboards for multidisciplinary and multisectoral collaborations that will improve the management and restoration of freshwater biodiversity.

     

Maximising lucerne (Medicago sativa L.) production with fixed‐length recovery intervals after defoliation in mild winter environments

Lucerne (Medicago sativa L.) is an important temperate legume for livestock production systems. Lucerne requires a recovery period after a defoliation event so that taproot energy and nutrient stores can be replenished. A field experiment examined the effects of recovery period management following defoliation, on lucerne herbage production and nutritive value at two contrasting sites in Victoria, Australia. Sites were established at Rutherglen and Hamilton, using established SARDI Seven lucerne stands. Treatments were short recovery (SR; plots cut at 21‐day intervals), long recovery (LR; plots cut at 42‐day intervals), new shoots (NS; plots cut when new shoots from the crown were at least 2 cm long) and new shoots + flowering (NSF; as for NS but plots were left to grow to reach late flowering from late summer to mid‐autumn). At each defoliation, measurements were made of phenology, dry matter production and herbage nutrient concentrations (neutral detergent fibre, crude protein, metabolisable energy and water‐soluble carbohydrate %). Persistence was measured at approximately 6‐month intervals. At both sites, lucerne persisted equally well in all treatments although SR showed some decline at Hamilton at the final measurement. LR led to a more productive pasture (in terms of cumulative dry matter, neutral detergent fibre, crude protein, metabolisable energy and water‐soluble carbohydrate %) than the three other treatments. The results indicate that phenological management systems that allow lucerne to replenish reserves through late summer and autumn are unnecessary in mild winter environments.