Isolation and characterization of 16 tetranucleotide microsatellite loci in the red panda (Ailurus fulgens)

A total of 15 polymorphic tetranucleotide microsatellite loci in the red panda, Ailurus fulgens, were characterized in this study. Based on evaluations of 33 red pandas, the number of observed alleles for each locus ranged from seven to 17 and the expected and observed heterozygosities were 0.412–0.897 and 0.121–0.909, respectively. The mean polymorphic information content was 0.721. These markers would greatly strengthen the utilization of microsatellite tools in genetic variation studies in red panda populations.     

Impact of the Arundo scale Rhizaspidiotus donacis (Hemiptera: Diaspididae) on the weight of Arundo donax (Poaceae: Arundinoideae) rhizomes in Languedoc southern France and Mediterranean Spain

Arundo donax L. (Poaceae) is native to Mediterranean Europe and invasive in the Rio Grande Basin of North America. Rhizomes from nine sites in France and Spain infested with a candidate control agent, the armoured scale Rhizaspidiotus donacis (Hemiptera: Diaspididae) weighed 50% less than those from nine sites without scale.     

A study on giant panda recognition based on images of a large proportion of captive pandas

1. As a highly endangered species, the giant panda (panda) has attracted significant attention in the past decades. Considerable efforts have been put on panda conservation and reproduction, offering the promising outcome of maintaining the population size of pandas. To evaluate the effectiveness of conservation and management strategies, recognizing individual pandas is critical. However, it remains a challenging task because the existing methods, such as traditional tracking method, discrimination method based on footprint identification, and molecular biology method, are invasive, inaccurate, expensive, or challenging to perform. The advances of imaging technologies have led to the wide applications of digital images and videos in panda conservation and management, which makes it possible for individual panda recognition in a noninvasive manner by using image‐based panda face recognition method.
2. In recent years, deep learning has achieved great success in the field of computer vision and pattern recognition. For panda face recognition, a fully automatic deep learning algorithm which consists of a sequence of deep neural networks (DNNs) used for panda face detection, segmentation, alignment, and identity prediction is developed in this study. To develop and evaluate the algorithm, the largest panda image dataset containing 6,441 images from 218 different pandas, which is 39.78% of captive pandas in the world, is established.
3. The algorithm achieved 96.27% accuracy in panda recognition and 100% accuracy in detection.
4. This study shows that panda faces can be used for panda recognition. It enables the use of the cameras installed in their habitat for monitoring their population and behavior. This noninvasive approach is much more cost‐effective than the approaches used in the previous panda surveys.

     

Protein Transport in Intact and Severed (Anucleate) Crayfish Giant Axons

Abstract: Using video-enhanced microscopy and a pulse-radiolabeling paradigm, we show that proteins synthesized in the medial giant axon cell body of the crayfish ( Procambarus clarkii ) are delivered to the axon via fast (∼62 mm/day) and slow (∼0.8 mm/day) transport components. These data confirm that the medial giant axon cell body provides protein to the axon in a manner similar to that reported for mammalian axons. Unlike mammalian axons, the distal (anucleate) portion of a medial giant axon remains intact and functional for >7 months after severance. This axonal viability persists long after fast transport has ceased and after the slow wave front of radiolabeled protein has reached the terminals. These data are consistent with the hypothesis that another source (i.e., local glial cells) provides a significant amount of protein to supplement that delivered to the medial giant axon by its cell body.     

Significance of new records of Tridacna squamosa Lamarck, 1819, in the Tuamotu and Gambier Archipelagos (French Polynesia)

The giant clam subfamily Tridacninae (family Cardiidae) is an important group of bivalve molluscs found throughout the Red Sea and Indo-Pacific, from East Africa to the Eastern Pacific biogeographic region. The Tridacna genus is currently revised with numerous cryptic species identified with molecular markers. New Tridacna records from the fringe of the known distribution areas are extremely useful to identify genetically unique species, geographic ranges, and to examine processes associated with species differentiation. While Tridacna maxima is abundant in French Polynesia (Central South Pacific Ocean) the larger fluted giant clam Tridacna squamosa was formerly reported only in the Austral Islands in the south. Following a recent survey that spanned 23 islands and atolls of the Society, Tuamotu and Gambier Archipelagos, the presence of T. squamosa between the Cook Islands and Pitcairn Islands is confirmed using both morphological and molecular information, suggesting a relic distribution across the Central Pacific Ocean. Tridacna squamosa is rare, but present throughout Tuamotu and Gambier. However, it remained undetected from the Society Islands, probably due to historical over-fishing. This species is valued by local inhabitants, and is sought after mainly as gifts and also for a limited local shell trade. The rarity of T. squamosa may call for conservation measures in the near future.     

Plant and frond dynamics of the giant kelp,Macrocystis pyrifera,forming a fringing zone in the Falkland Islands

Fluctuations in plant and frond characteristics are described for Macrocystis pyrifera (L.) C. Agardh (Laminariales, Phaeophyta) forming a fringing zone in the Falkland Islands. Giant kelp plants were sampled along a transect in the austral autumn (May 1986) and late spring (December 1986) which, according to previous frond weight analysis, were the times when extremes in population parameters were expected. Plant density and holdfast wet weights were similar for both seasons, but plants had more fronds and the fronds weighed more in spring than in autumn. Consequently, in autumn the frond biomass (1·1 wet kg m^?2) and productivity (34·1 wet g m^?2 d^?1) were lower than in spring, when a biomass of 5·0 wet kg m^?2 and a productivity of 72·4 wet g m^?2 d^?1 were recorded. Production of new fronds and loss of old fronds were determined at monthly intervals between April 1986 and March 1987. New frond production rates followed fluctuations in the quantity of light and varied between 0·08 and 0·48 fronds per plant per day. Frond loss rates did not show a seasonal pattern and fluctuated between 0·05 and 0·42 fronds per plant per day. It is suggested that the Falkland Islands Macrocystis population is more stable than most other giant kelp beds at high latitudes, because of the absence of winter storms.     

The brain structure of selected trypanorhynch tapeworms

The brain architecture in four species of tapeworms from the order Trypanorhyncha has been studied. In all species, the brain consists of paired anterior and lateral lobes, and an unpaired central lobe. The anterior lobes connect by dorsal and ventral semicircular commissures; the central and lateral lobes connect by a median and an X-shaped crisscross commissure. In the center of the brain, five well-developed compact neuropils are present. The brain occupies a medial position in the scolex pars bothrialis. The ventral excretory vessels are situated outside the lateral lobes of the brain; the dorsal excretory vessels are located inside the brain and dorsal to the median commissure. The brain gives rize four anterior proboscis nerves and four posterior bulbar nerves with myelinated giant axons (GAs). The cell bodies of the GAs are located within the X-commissure and in the bulbar nerves. Highly developed serotonergic neuropils are present in the anterior and lateral lobes; numerous 5-HT neurons are found in the brain lobes including the central unpaired lobe. The X-cross commissure consists of the α-tub-immunoreactive and 5-HT-IR neurites. Eight ultrastructural types of neurons were found in the brain of the three species investigated. In addition, different types of synapses were present in the neuropils. Glial cells ensheath the brain lobes, the neuropils, the GAs, and the bulbar nerves. Glia cell processes form complex branching patterns of thin cytoplasmic sheets sandwiched between adjacent neural processes and filling the space between neurons. Multilayer myelin-like envelopes and a mesaxon-like structure have been found in Trypanorhyncha nervous system. We compared the brain architecture of Trypanorhyncha with that of an early basal cestode taxon, that is, Diphyllobothriidea, and present a hypothesis about the homology of the anterior brain lobes in order Trypanorhyncha; and the lateral lobes and median commissure are homologous brain structures within Eucestoda.     

Evolutionary dynamics of giant viruses and their virophages

Giant viruses contain large genomes, encode many proteins atypical for viruses, replicate in large viral factories, and tend to infect protists. The giant virus replication factories can in turn be infected by so called virophages, which are smaller viruses that negatively impact giant virus replication. An example is Mimiviruses that infect the protist Acanthamoeba and that are themselves infected by the virophage Sputnik. This study examines the evolutionary dynamics of this system, using mathematical models. While the models suggest that the virophage population will evolve to increasing degrees of giant virus inhibition, it further suggests that this renders the virophage population prone to extinction due to dynamic instabilities over wide parameter ranges. Implications and conditions required to avoid extinction are discussed. Another interesting result is that virophage presence can fundamentally alter the evolutionary course of the giant virus. While the giant virus is predicted to evolve toward increasing its basic reproductive ratio in the absence of the virophage, the opposite is true in its presence. Therefore, virophages can not only benefit the host population directly by inhibiting the giant viruses but also indirectly by causing giant viruses to evolve toward weaker phenotypes. Experimental tests for this model are suggested.     

Energetics of gating MscS by membrane tension in azolectin liposomes and giant spheroplasts

Mechanosensitive (MS) ion channels are molecular sensors that detect and transduce signals across prokaryotic and eukaryotic cell membranes arising from external mechanical stimuli or osmotic gradients. They play an integral role in mechanosensory responses including touch, hearing, and proprioception by opening or closing in order to facilitate or prevent the flow of ions and organic osmolytes. In this study we use a linear force model of MS channel gating to determine the gating membrane tension (γ) and the gating area change (ΔA) associated with the energetics of MscS channel gating in giant spheroplasts and azolectin liposomes. Analysis of Boltzmann distribution functions describing the dependence of MscS channel gating on membrane tension indicated that the gating area change (ΔA) was the same for MscS channels recorded in both preparations. The comparison of the membrane tension (γ) gating the channel, however, showed a significant difference between the MscS channel activities in these two preparations.