Population Genetics of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) across Multiple Spatial Scales

Conservation genetics is a powerful tool to assess the population structure of species and provides a framework for informing management of freshwater ecosystems. As lotic habitats become fragmented, the need to assess gene flow for species of conservation management becomes a priority. The eastern hellbender (Cryptobranchus alleganiensis alleganiensis) is a large, fully aquatic paedamorphic salamander. Many populations are experiencing declines throughout their geographic range, yet the genetic ramifications of these declines are currently unknown. To this end, we examined levels of genetic variation and genetic structure at both range-wide and drainage (hierarchical) scales. We collected 1,203 individuals from 77 rivers throughout nine states from June 2007 to August 2011. Levels of genetic diversity were relatively high among all sampling locations. We detected significant genetic structure across populations (F_st values ranged from 0.001 between rivers within a single watershed to 0.218 between states). We identified two genetically differentiated groups at the range-wide scale: 1) the Ohio River drainage and 2) the Tennessee River drainage. An analysis of molecular variance (AMOVA) based on landscape-scale sampling of basins within the Tennessee River drainage revealed the majority of genetic variation (∼94–98%) occurs within rivers. Eastern hellbenders show a strong pattern of isolation by stream distance (IBSD) at the drainage level. Understanding levels of genetic variation and differentiation at multiple spatial and biological scales will enable natural resource managers to make more informed decisions and plan effective conservation strategies for cryptic, lotic species.     

The content of protein, fibre and minerals of leaves of selected Acacia species indigenous to north-western Tanzania

Browse tree leaves of six species of Acacia (A. angustissima L., A. drepanolobium L., A. nilotica L., A. polyacantha L., A. senegal L., A. tortilis L.) were screened for chemical composition, including minerals and trace elements. Crude protein (CP) varied among the species from 145 (A. senegal) to 229 g/kg DM (A. angustissima). The species had moderate to high levels of minerals. The concentrations of Ca, P, Mg and S varied among the species from 14.6-31.5, 3.5-4.9, 1.4-3.0 and 1.7-2.8 g/kg DM, respectively. The forages showed relatively low concentrations of trace elements. Content of trace elements varied among the species from 4.5-23.8, 99.4-173.6, 146.2-432, 41.0-90.1, 10.9-22.2 and 0.05-0.65 mg/kg DM for Cu, Mo, Fe, Mn, Zn and Co, respectively. All leaves of browse species would meet the normal requirements for Ca, P, Mg and S in ruminants, although some species had higher levels of Ca than tabulated mineral requirements in livestock. Assayed Cu, Mn, Zn and Co would satisfy the lower range of recommended requirements of trace elements depending on their bioavailability. Therefore, browse leaves from Acacias could form good sources of CP and mineral supplements to ruminants.     

Learning to Avoid Dangerous Habitat Types by Aquatic Salamanders,Eurycea tynerensis

There should be intense selection for predation avoidance mechanisms when prey live in close proximity to their predators. Prey individuals that can learn to associate habitat features with high levels of predation risk should experience increased survival if they subsequently avoid those habitats. We tested whether or not habitat learning occurred in a benthic stream community consisting of adult Oklahoma salamander (Eurycea tynerensis) prey and a syntopic predatory fish, the banded sculpin (Cottus carolinae). We exposed individual salamanders to chemical stimuli from sculpin, non‐predatory tadpoles, or a blank control in training tanks containing either rocks or grass. Two days later, the salamanders were tested in tanks that offered a choice of rocks or grass. Salamanders showed significant avoidance of the habitat where they had previously encountered chemical cues from sculpin in comparison to the non‐predatory controls. Learning to avoid dangerous habitats may be particularly important for prey whose predators are visually cryptic ambush foragers, such as sculpin.     

In vitro antiviral activity of sulfated Auricularia auricula polysaccharides

Total Auricularia auricula polysaccharide (AAP(t)) was prepared by extracting and removing the proteins. Column chromatography was used to further graded it into AAP(1) and AAP(2). Three AAPs were modified by chlorosulfonic acid-pyridine method to obtain three sulfated AAPs (sAAPs), sAAP(t), sAAP(1) and sAAP(2), respectively. Three sAAPs and Newcastle disease virus (NDV) were added into cultivation system of chicken embryo fibroblast (CEF) in three manners, pre-, post- and simultaneous-adding polysaccharide with NDV respectively, taking three non-modified AAPs as control. Their anti-viral activities were compared by MTT method. The results showed that sAAPs and AAPs at a certain concentration could significantly inhibit the cellular infectivity of NDV in three manners. The effects of sAAPs were better than that of AAPs. It indicated that sulfated modification could enhance the antiviral activity of AAP. sAAP(1) and sAAP(t) possessed stronger activity and would be as the component of a new-type antiviral drug.     

Health and habitat quality assessment for the eastern hellbender (Cryptobranchus alleganiensis alleganiensis) in Indiana, USA

The eastern hellbender (Cryptobranchus alleganiensis alleganiensis) has experienced precipitous population declines throughout its range. Numerous factors are speculated to be involved, but no empirical evidence has been presented for any. We implemented a population-wide health assessment in Indiana, USA, examining both the physical well-being of individuals and the quality of their habitat. Physicochemical parameters were analyzed directly in the field and later in the laboratory, when appropriate. Samples were collected June 2008-October 2008 and June 2009-September 2009 for reproductive analysis, blood screening, and disease prevalence. Of 27 chemicals screened in water samples, three were found in the study site, including atrazine. Atrazine was found at levels reported to cause reproductive problems in other amphibians. Vitellogenin was detected only in females and proved a reliable indicator of sex. Sperm parameters were generally of high quality and similar to other populations. Most plasma parameters were similar between sexes, although there were significant differences in calcium and potassium concentrations. Abnormalities were common, occurring in 68% of individuals. No hemoparasites were found, but amphibian chytrid fungus (Batrachochytrium dendrobatidis) was detected on one individual. Our findings establish a baseline for hematology and water-quality parameters that can be used as a model for evaluating population health throughout the hellbender range.     

Foraging behaviour of wild impala (Aepyceros melampus) and Burchell's zebra (Equus burchelli) in relation to sward height

Foraging behaviour plays a key role in the interaction between herbivores and vegetation, their predominant food source. Understanding this interaction is crucial to providing information that is useful for conservation of herbivores. The objective of this study was to determine how sward height influences functional response and movement patterns of free ranging wild impala and zebra at the Kenya Wildlife Service Training Institute. The study was conducted for 3 months. Sward height is an important parameter that indicates how intensive a sward has been grazed and it influences intake rate through its effect on bite size. Bite size, instantaneous intake rate, specific mass intake rate and feeding station interval for impala and zebra increased with sward height. Sward height in combination with an animal's sex was found to have a profound effect on specific mass intake rate in impala. Zebra had a longer feeding station interval and lower stepping rate in tall swards compared to impala. Despite differences in their specific body mass and digestive strategies, impala and zebra maximized their intake rates in tall swards as a trade‐off among the swards. Tall swards are therefore critical in the study area and should be protected from bush encroachment which is a persistent problem.     

Modest catalysis of the decarboxylation of orotate by hydrogen bonding: a theoretical model for orotidine- 5' -monophosphate decarboxylase

As a model for interactions present in the active site of orotidine-5'-monophosphate decarboxylase (ODCase), the effect of hydrogen bonds to the carbonyl groups (O-2 and O-4) of orotic acid and its decarboxylation product was probed with ab initio calculations. We have found that the transition state/carbanion intermediate is a better proton receptor and therefore, the hydrogen bonds can be a modest source of catalysis. Comparison of the calculated data with results from site-directed mutagenesis provides some insights into the polarity of the active site.     

Effects of anticancer drug docetaxel on the structure and function of the rabbit olfactory mucosa

Docetaxel (DCT) is an anticancer drug which acts by disrupting microtubule dynamics in the highly mitotic cancer cells. Thus, this drug has a potential to affect function and organization of tissues exhibiting high cellular turnover. We investigated, in the rabbit, the effects of a single human equivalent dose (6.26 mg/kg, i.v.) of DCT on the olfactory mucosa (OM) through light and electron microscopy, morphometry, Ki-67 immunostaining, TUNEL assay and the buried food test for olfactory sensitivity. On post-exposure days (PED) 5 and 10, there was disarrangement of the normal cell layering in the olfactory epithelium (OE), apoptotic death of cells of the OE, Bowman's glands and axon bundles, and the presence (including on PED 3) of blood vessels in the bundle cores. A decrease in bundle diameters, olfactory cell densities and cilia numbers, which was most significant on PED 10 (49.3%, 63.4% and 50%, respectively), was also evident. Surprisingly by PED 15, the OM regained normal morphology. Furthermore, olfactory sensitivity decreased progressively until PED 10 when olfaction was markedly impaired, and with recovery from the impairment by PED 15. These observations show that DCT transiently alters the structure and function of the OM suggesting a high regenerative potential for this tissue.