The effect of red light in the high irradiance reaction of phytochrome:

Abstract. A proposal has recently been made (Johnson & Tasker, 1979) that phytochrome acts through the multiplicative effect of two components of the phytochrome system, only one of them being Pfr and the other a product of the photoconversion reaction Pr → Pfr . It has been shown previously that HIR action spectra based on this assumption show a good resemblance to the observed responses with the possible exception of the red region of the spectrum. There, a greater response is predicted than is often observed and fluence rate dependency is predicted, on which matter there is disagreement in the literature.
The experiments reported here show that, because chlorophyll is formed in red light but not in far-red, chlorophyll screening lowers the effective fluence rate in red light with respect to phytochrome. When such screening is eliminated the observed responses show strong fluence rate dependency, as predicted. Evidence is also presented to support the conclusion that the two proposed effectors must act together multiplicatively.     

Pre-breeding diet influences ornament size in the Rhinoceros Auklet Cerorhinca monocerata

Understanding the mechanisms that influence variation in sexually selected ornaments in seabirds has been challenging owing to the difficulty of capturing and sampling individuals outside of the breeding period when ornaments are usually grown. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes were used to examine the influence of pre-breeding diet composition on ornament size in the Rhinoceros Auklet Cerorhinca monocerata , a socially monogamous seabird that breeds in the North Pacific. We analysed stable isotopes in adult feathers grown during the pre-alternate moult, which allowed us to infer diet composition during the pre-breeding (February–March) period. Females that fed more on inshore fish had larger horns than females that fed more on euphausiids (also known as krill; Euphausiacea). Body size was a stronger predictor of horn height in males than females, suggesting that ornaments may serve as different signals for each sex. This study provides evidence that diet during the pre-breeding period can influence ornament size and emphasizes the importance of understanding individual ecology throughout the annual cycle for determining the factors that influence mate choice and fitness.     

Endemic evolutionary radiation of Rhagada land snails (Pulmonata: Camaenidae) in a continental archipelago in northern Western Australia

In the Dampier Archipelago of Western Australia's Pilbara Region, several locally endemic, morphologically distinctive species of Rhagada land snails occur, contrasting with the morphologically conservative species with wider distributions on the adjacent mainland. To test alternative origins of this unusual local diversity in a continental archipelago, we examined sequences of the cytochrome oxidase subunit 1 and 16S mitochondrial genes in 22 described species and eight undescribed forms, including all known morphospecies from the Pilbara Region's Dampier Archipelago and adjacent mainland. Phylogenetic analyses consistently resolved four, deep clades within the Pilbara Region, with a mean sequence divergence of 15–18%. All but one of the species from the Dampier Archipelago formed one of the major clades, indicating that the morphological radiation in the archipelago evolved locally, rather than through multiple, relictual mainland lineages. Morphological divergence spanning almost that of the entire genus was within a subclade with sequence divergence < 4%, highlighting the disconnection between morphological diversification and levels of molecular genetic divergence. This in situ morphological radiation in the Dampier Archipelago, which transcends variation seen over much larger distances on the mainland, is unusual for a continental archipelago, and may relate to local heterogeneity of land forms. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 316–327.     

Characterization of human natural killer cells for therapeutic use

As a part of the innate immune system, natural killer (NK) cells are cytotoxic lymphocytes that can exert cytotoxic activity against infected or transformed cells. Furthermore, due to their expression of a functional Fc receptor, they have also been eluded as a major effector fraction in antibody-dependent cellular cytotoxicity. These characteristics have led to multiple efforts to use them for adoptive immunotherapy against various malignancies.  There are now at least 70 clinical trials testing the safety and efficacy of NK cell products around the world in early-phase clinical trials. NK cells are also being tested in the context of tumor retargeting via chimeric antigen receptors, other genetic modification strategies, as well as tumor-specific activation strategies such as bispecific engagers with or without cytokine stimulations. One advantage of the use of NK cells for adoptive immunotherapy is their potential to overcome HLA barriers. This has led to a plethora of sources, such as cord blood hematopoietic stem cells and induced pluripotent stem cells, which can generate comparatively high cytotoxic NK cells to peripheral blood counterparts. However, the variety of the sources has led to a heterogeneity in the characterization of the final infusion product. Therefore, in this review, we will discuss a comparative assessment strategy, from characterization of NK cells at collection to final product release by various phenotypic and functional assays, in an effort to predict potency of the cellular product.     

Molecular cloning and sequence analysis of a chicken ornithine decarboxylase cDNA

A chicken embryo cDNA library was screened with a mouse probe for ornithine decarboxylase (ODC) and 14 positively hybridizing clones isolated. The longest of these (1.7 kb) was sub-cloned and sequenced. It is estimated that the clone comprises approximately 98% of the coding region for chicken ODC. The DNA sequence shows 78% identity with the human ODC cDNA sequence and the deduced amino acid sequence is almost 90% homologous to mouse and human. Both the peptide and cDNA sequences show interesting potential regulatory features which are discussed here.     

Foraging guild membership explains variation in waterbird responses to the hydrological regime of an arid‐region flood‐pulse river in Namibia

1. Little is known about hydrological influences on tropical waterbird communities. We used a 16‐year data set (1991–2007) of waterbird censuses, together with a classification of observed species into foraging guilds, to explore the relationships between natural variations in flow regime, foraging guild and the community composition of waterbirds at the Okavango River in the Caprivi Strip of north‐eastern Namibia, southern Africa. 2. We addressed three hypotheses to explain variation in waterbird community composition: (i) exploitation (birds move towards resource‐rich patches to exploit periods of high food abundance); (ii) escapism (declines in regional habitat quality force birds to aggregate in perennial waterbodies); and (iii) interaction (bird assemblages are dominated by intra‐ and interspecific interactions, such as flock formation for breeding or moulting, that can be explained better by life history demands or competition than by resource availability). 3. Waterbirds in different foraging guilds responded strongly but at different periods to changes in the hydrological environment, creating a complex but predictable successional pattern in community composition through time. Deep‐water feeders responded fastest (abundance peaking 2 months post‐flood), followed by shallow‐water feeders (4 months) and emergent vegetation feeders (7 months). Species that forage on short vegetation or in mud showed a bimodal response with peaks in abundance at 3 and 8 months post‐flood. 4. Our results indicated a strong effect of the local flow regime and hence supported the exploitation hypothesis. The foraging guild approach allowed us to identify clear patterns in a highly complex ecosystem and shows considerable promise as an analytical tool for similar data sets. Our results further suggest that while the entire bird community will be affected by hydrological alterations such as impoundments, water extraction and climate change, deep‐water feeders may be one of the most vulnerable groups.     

Long‐term impacts of invasive species on a native top predator in a large lake system

1. Declining abundances of forage fish and the introduction and establishment of non‐indigenous species have the potential to substantially alter resource and habitat exploitation by top predators in large lakes. 2. We measured stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) in field‐collected and archived samples of Lake Ontario lake trout (Salvelinus namaycush) and five species of prey fish and compared current trophic relationships of this top predator with historical samples. 3. Relationships between δ¹⁵N and lake trout age were temporally consistent throughout Lake Ontario and confirmed the role of lake trout as a top predator in this food web. However, δ¹³C values for age classes of lake trout collected in 2008 ranged from 1.0 to 3.9‰ higher than those reported for the population sampled in 1992. 4. Isotope mixing models predicted that these changes in resource assimilation were owing to the replacement of rainbow smelt (Osmerus mordax) by round goby (Neogobius melanostomus) in lake trout diet and increased reliance on carbon resources derived from nearshore production. This contrasts with the historical situation in Lake Ontario where δ¹³C values of the lake trout population were dominated by a reliance on offshore carbon production. 5. These results indicate a reduced capacity of the Lake Ontario offshore food web to support the energetic requirements of lake trout and that this top predator has become increasingly reliant on prey resources that are derived from nearshore carbon pathways.     

Floristic richness of three perhumid New Zealand alpine plant communities in comparison with other regions

Abstract Results are presented on vascular species richness in three representative alpine plant communities at 1040–1410 m on Mt Burns in the perhumid Fiordland region, a hotspot of alpine plant diversity, in south‐western South Island, New Zealand. Overall species richness was not dissimilar between the three communities in any of the eight plot sizes (mean values of 20.8–24.4 species in the largest plots of 100 m²), even though coefficients of floristic similarity were small (17.9; 23.5) between both low‐alpine communities (snow tussock‐shrubland and snow tussock grassland) and the high‐alpine cushion fellfield. Vascular species richness was generally similar to that in the few other oceanic New Zealand alpine communities for which data are available. The decline in richness from the low‐alpine to high‐alpine zones, revealed in more comprehensive records from two other regions with generally similar oceanic environments, was not recorded, indeed was reversed, on Mt Burns. Whether the recognized biodiversity hotspot of Fiordland has a generally richer high‐alpine flora than other regions in New Zealand needs further examination. The general pattern of alpine floristic richness in relation to elevation, in New Zealand, also prevails in most alpine regions abroad, usually under much more extreme continental environments. This pattern is usually ascribed to the associated decrease in temperature. Both the small size of the land mass and/or associated environmental conditions may be implicated but clarification awaits further data, preferably collected with standardized procedures.     

DELIMITING SPAWNING AREAS OF WEAKFISH CYNOSCION REGALIS (FAMILY SCIAENIDAE) IN PAMLICO SOUND,NORTH CAROLINA USING PASSIVE HYDROACOUSTIC SURVEYS

ABSTRACT

Exact locations of spawning areas used by marine fishes are needed to design marine reserves and estimate spawning stocks. The location of spawning areas of soniferous fishes such as weakfish Cynoscion regalis can be determined by means of passive hydroacoustic surveys. We conducted nocturnal hydrophone surveys at 12 locations in Pamlico Sound in May of 1996 and 1997. Digital audio tapes were made of weakfish “purring” sounds, the tapes were analyzed spectrographically and compared with ichthyoplankton surveys taken at the same stations and times. All weakfish “purring” sounds were recorded at stations near inlets. Maximum sound pressure levels recorded after sunset were 127 dB (re 1 (μPa) for individual weakfish, but reached a maximum of 147 dB when weakfish and other fish were producing sounds simultaneously. The maximum distance that an individual weakfish “purr” can be detected above the background sound, assuming a cylindrical spreading model, is approximately 50 m. There was a strong association (r = 0.78) between the log₁₀— transformed abundance of early-stage sciaenid-type eggs and maximum sound pressure levels, with the greatest numbers occurring at the inlet stations. These results suggest that passive hydroacoustic surveys can be used to delimit spawning areas for conservation and management purposes.