A study of oestrus and fecundity in a laboratory colony of Mouse opossums (Marmosa robinsoni)

Twenty wild caught Mouse opossums Marmosa robinsoni Bangs 1898 formed the basis of a laboratory colony which was maintained at the Brookfield Zoo during 1971–3. Approximately 250 young including 3rd-generation descendants were produced.
M. robinsoni is polyoestrous with a mean cycle length of 25.5±0.5 days. Vaginal oestrus, which normally lasts three days, is accompanied by a pronounced cycle of cornification and mucification. During this period large numbers of desquamated epithelial cells and mucus are found in the urine. Females are sexually receptive 24 hours before cornified cells first appear in the urine and receptivity lasts two to four days. Fertile copulation takes place throughout this period. Ovulation is spontaneous and occurs late in oestrus. The mean number of corpora lutea recorded was 19.8±0.9 ( n =23).
Anovular cycles, associated with atresia of mature Graafian follicles, were found in approximately 25% of the females. The sterile cycles, which had a mean length of 15.6±0.7 days, were not always accompanied by a behavioural oestrus. Observations on the behaviour of introduced pairs provided direct evidence of sexual incompatibility. Sexual incompatibility was found to have been responsible for at least 10% of the unsuccessful pairings recorded during the study.
There were no indications in the Brookfield colony of the decline in productivity among laboratory-bred animals reported in other Marmosa colonies. Litter-sizes and litter-rates in the F₁ and F₂ generations did not differ from those in the wild-caught generation. However, the fact that only one out of three pairings produced young suggests that productivity in the colony was lower than in the wild. The cause of this low productivity was not established.     

ACEH/ACE2 is a novel mammalian metallocarboxypeptidase and a homologue of angiotensin-converting enzyme insensitive to ACE inhibitors

A human zinc metalloprotease (termed ACEH or ACE2) with considerable homology to angiotensin-converting enzyme (ACE) (EC 3.4.15.1) has been identified and subsequently cloned and functionally expressed. The translated protein contains an N-terminal signal sequence, a single catalytic domain with zinc-binding motif (HEMGH), a transmembrane region, and a small C-terminal cytosolic domain. Unlike somatic ACE, ACEH functions as a carboxypeptidase when acting on angiotensin I and angiotensin II or other peptide substrates. ACEH may function in conjunction with ACE and neprilysin in novel pathways of angiotensin metabolism of physiological significance. In contrast with ACE, ACEH does not hydrolyse bradykinin and is not inhibited by typical ACE inhibitors. ACEH is unique among mammalian carboxypeptidases in containing an HEXXH zinc motif but, in this respect, resembles a bacterial enzyme, Thermus aquaticus (Taq) carboxypeptidase (EC 3.4.17.19). Collectrin, a developmentally regulated renal protein, is homologous with the C-terminal region of ACEH but has no similarity with ACE and no catalytic domain. Thus, the ACEH protein may have evolved as a chimera of a single ACE-like domain and a collectrin domain. The collectrin domain may regulate tissue response to injury whereas the catalytic domain is involved in peptide processing events.     

CKAP4/p63 is a receptor for the frizzled-8 protein-related antiproliferative factor from interstitial cystitis patients

Antiproliferative factor (APF) is a low molecular weight sialoglycopeptide that is secreted by bladder cells from interstitial cystitis patients and is a potent inhibitor of both normal bladder epithelial and bladder carcinoma cell proliferation. We hypothesized that APF may produce its antiproliferative effects by binding to a transmembrane receptor. This study demonstrates that cytoskeleton-associated protein 4/p63 (CKAP4/p63), a type II transmembrane receptor, binds with high affinity to APF. The antiproliferative activity of APF is effectively inhibited by preincubation with anti-CKAP4/p63-specific antibodies, as well as by short interfering RNA knockdown of CKAP4/p63. Immunofluorescent confocal microscopy showed co-localization of anti-CKAP4/p63 and rhodamine-labeled synthetic APF binding in both cell membrane and perinuclear areas. APF also inhibits the proliferation of HeLa cervical carcinoma cells that are known to express CKAP4/p63. These data indicate that CKAP4/p63 is an important epithelial cell receptor for APF.     

In vitro assembly into virus-like particles is an intrinsic quality of Pichia pastoris derived HCV core protein

Different variants of hepatitis C virus core protein (HCcAg) have proved to self-assemble in vitro into virus-like particles (VLPs). However, difficulties in obtaining purified mature HCcAg have limited these studies. In this study, a high degree of monomeric HCcAg purification was accomplished using chromatographic procedures under denaturing conditions. Size exclusion chromatography and sucrose density gradient centrifugation of renatured HCcAg (in the absence of structured RNA) under reducing conditions suggested that it assembled into empty capsids. The electron microscopy analysis of renatured HCcAg showed the presence of spherical VLPs with irregular shapes and an average diameter of 35nm. Data indicated that HCcAg monomers assembled in vitro into VLPs in the absence of structured RNA, suggesting that recombinant HCcAg used in this work contains all the information necessary for the assembly process. However, they also suggest that some cellular factors might be required for the proper in vitro assembly of capsids.     

Selecting appropriate methods of knowledge synthesis to inform biodiversity policy

Responding to different questions generated by biodiversity and ecosystem services policy or management requires different forms of knowledge (e.g. scientific, experiential) and knowledge synthesis. Additionally, synthesis methods need to be appropriate to policy context (e.g. question types, budget, timeframe, output type, required scientific rigour). In this paper we present a range of different methods that could potentially be used to conduct a knowledge synthesis in response to questions arising from knowledge needs of decision makers on biodiversity and ecosystem services policy and management. Through a series of workshops attended by natural and social scientists and decision makers we compiled a range of question types, different policy contexts and potential methodological approaches to knowledge synthesis. Methods are derived from both natural and social sciences fields and reflect the range of question and study types that may be relevant for syntheses. Knowledge can be available either in qualitative or quantitative form and in some cases also mixed. All methods have their strengths and weaknesses and we discuss a sample of these to illustrate the need for diversity and importance of appropriate selection. To summarize this collection, we present a table that identifies potential methods matched to different combinations of question types and policy contexts, aimed at assisting teams undertaking knowledge syntheses to select appropriate methods.     

Complex phylogenetic distribution of a non-canonical genetic code in green algae

Background  

A non-canonical nuclear genetic code, in which TAG and TAA have been reassigned from stop codons to glutamine, has evolved independently in several eukaryotic lineages, including the ulvophycean green algal orders Dasycladales and Cladophorales. To study the phylogenetic distribution of the standard and non-canonical genetic codes, we generated sequence data of a representative set of ulvophycean green algae and used a robust green algal phylogeny to evaluate different evolutionary scenarios that may account for the origin of the non-canonical code.     

Using Effort to Measure Reward Value of Faces in Children with Autism

According to one influential account, face processing atypicalities in autism reflect reduced reward value of faces, which results in limited attention to faces during development and a consequent failure to acquire face expertise. Surprisingly, however, there is a paucity of work directly investigating the reward value of faces for individuals with autism and the evidence for diminished face rewards in this population remains equivocal. In the current study, we measured how hard children with autism would work to view faces, using an effortful key-press sequence, and whether they were sensitive to the differential reward value of attractive and unattractive faces. Contrary to expectations, cognitively able children with autism did not differ from typically developing children of similar age and ability in their willingness to work to view faces. Moreover, the effort expended was strongly positively correlated with facial attractiveness ratings in both groups of children. There was also no evidence of atypical reward values for other, less social categories (cars and inverted faces) in the children with autism. These results speak against the possibility that face recognition difficulties in autism are explained by atypical reward value of faces.     

Statistical optimisation of growth conditions and diesel degradation by the Antarctic bacterium,Rhodococcus sp. strain AQ5‒07

Petroleum pollution is a major concern in Antarctica due to the persistent nature of its hydrocarbon components coupled with the region’s extreme environmental conditions, which means that bioremediation approaches are largely inapplicable at present. The current study assessed the ability of the psychrotolerant phenol-degrader, Rhodococcus sp. strain AQ5-07, to assimilate diesel fuel as the sole carbon source. Factors expected to influence the efficiency of diesel degradation, including the initial hydrocarbon concentration, nitrogen source concentration and type, temperature, pH and salinity were studied. Strain AQ5-07 displayed optimal cell growth and biodegradation activity at 1% v/v initial diesel concentration, 1 g/L NH₄Cl concentration, pH 7 and 1% NaCl during one-factor-at-a-time (OFAT) analyses. Strain AQ5-07 was psychrotolerant based on its optimum growth temperature being near 20 °C. In conventionally optimised media, strain AQ5-07 showed total petroleum hydrocarbons (TPH) mineralisation of 75.83%. However, the optimised condition for TPH mineralisation predicted through statistical response surface methodology (RSM) enhanced the reduction to 90.39% within a 2 days incubation. Our preliminary data support strain AQ5-07 being a potential candidate for real-field soil bioremediation by specifically adopting sludge-phase bioreactor system in chronically cold environments such as Antarctica. The study also confirmed the utility of RSM in medium optimisation.

     

Manganese (hyper)accumulation within Australian Denhamia (Celastraceae): an assessment of the trait and manganese accumulation under controlled conditions

Plant and Soil - The genus Denhamia(Celastraceae) includes fifteen Australian species, many of which have a propensity for manganese (Mn) (hyper)accumulation. Among the key aims of this study were...