Climate and vegetation history of the midcontinent from 75 to 25 ka: A speleothem record from crevice cave, missouri, USA

Four Missouri stalagmites yield consistent overlapping records of oxygen and carbon isotopic changes and provide a climate and vegetation history with submillennial resolution from 75 to 25 thousand years ago (ka). The thorium-230-dated records reveal that between 75 and 55 ka, the midcontinental climate oscillated on millennial time scales between cold and warm, and vegetation alternated among forest, savanna, and prairie. Temperatures were highest and prairie vegetation peaked between 59 and 55 ka. Climate cooled and forest replaced grassland at 55 ka, when global ice sheets began to build during the early part of Marine Oxygen Isotope Stage 3.     

A long-snouted predatory dinosaur from africa and the evolution of spinosaurids

Fossils discovered in Lower Cretaceous (Aptian) rocks in the Tenere Desert of central Niger provide new information about spinosaurids, a peculiar group of piscivorous theropod dinosaurs. The remains, which represent a new genus and species, reveal the extreme elongation and transverse compression of the spinosaurid snout. The postcranial bones include blade-shaped vertebral spines that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous.     

Enhancing rotifer Brachionus calyciflorus population growth with commercial probiotics

The effect of a commercial probiotic (NanoCrusta, Altacrusta, Mexico City, Mexico) on the growth performance of Brachionus calyciflorus Pallas, 1766, was evaluated. In a first approach, probiotics were supplied in four densities (2.0 × 10³, 1.1 × 10⁵, 2.1 × 10⁵ and 2.1 × 10⁶ cells/ml), alone and in combination with Chlorella vulgaris (1 × 10⁶ cells/ml). The test rotifer did not grow on the probiotic alone. However, when probiotics + C. vulgaris were added, the maximum densities (D_max; ind/ml) and population growth rates (r) observed were higher. In the second experiment, probiotics were supplied at five higher densities (2.1 × 10⁶, 4.2 × 10⁶, 8.5 × 10⁶, 1.7 × 10⁷ and 3.4 × 10⁷ cells/ml) with C. vulgaris and a control treatment with only C. vulgaris (probiotic‐free). Treatments supplied with probiotics between 2.1 × 10⁶ and 1.7 × 10⁷ cells/ml showed significantly higher D_max and r than the control treatment. The results showed a positive effect of probiotic bacteria when supplied with C. vulgaris. The best outcome showed a D_max 2.16 times and an r 1.63 times higher than the density of the control treatment. Growth rates were higher in the treatments with probiotics compared to the control. We conclude that application of NanoCrusta is feasible to improve B. calyciflorus production, but the effects need to be tested in larger scales.     

The mutagenesis of a type IV secretion system locus of Piscirickettsia salmonis leads to the attenuation of the pathogen in Atlantic salmon,Salmo salar

Piscirickettsiosis is a threatening infectious disease for the salmon industry, due to it being responsible for significant economic losses. The control of outbreaks also poses considerable environmental challenges. Despite Piscirickettsia salmonis having been discovered as the aetiological agent of the disease more than 25 years ago, its pathogenicity remains poorly understood. Among virulence factors identified so far, type four secretion systems (T4SS) seem to play a key role during the infection caused by the bacterium. We report here the genetic manipulation of P. salmonis by means of the transference of plasmid DNA in mating assays. An insertion cassette was engineered for targeting the icmB gene, which encodes a putative T4SS‐ATPase and is carried by one of the chromosomal T4SS clusters found within the genome of P. salmonis PM15972A1, a virulent representative of the EM‐90‐like strain. The molecular characterization of the resulting mutant strain demonstrated that the insertion interrupted the target gene. Further in vitro testing of the icmB mutant showed a dramatic drop in infectivity as tested in CHSE‐214 cells, which is in agreement with its attenuated behaviour observed in vivo. Altogether, our results demonstrate that, similar to other facultative intracellular pathogens, P. salmonis’ virulence relies on an intact T4SS.     

Transduction and Transplantation of Spermatogonia into the Testis of Ram Lambs through the Extra-testicular Rete

Spermatogonial transplantation will provide a new way to study spermatogenesis in domestic animals, disseminate male genetics and produce transgenic animals, if efficiency can be improved. We evaluated a 'surgical' method for transplanting donor cells into testes of ram lambs, where the head of the epididymis is reflected, and a catheter introduced into the extra-testicular rete testis. We also tested transduction of ram spermatogonia with a lentiviral (LV) vector as a means to identify permanent colonization, and introduce genes into donor cells. Eight ram lambs, 11- to 13-week olds, were the recipients: in five, spermatogonia were injected into one testis, and the contralateral testis was an un-manipulated control: in two, spermatogonia were injected into one testis and the contralateral was sham-injected: in one, both testes were injected. Six lambs received spermatogonia labelled with a cell-tracking dye and these were collected 1 or 2 weeks after transplantation; three lambs received spermatogonia transduced with a LV vector driving the expression of enhanced Green Fluorescence Protein and these were collected after 2 months. Donor cells were detected by immunohistochemistry in tubules of seven of nine recipient testes. Approximately 22% of tubule cross-sections contained donor cells immediately after transplantation, and 0.2% contained virally transduced cells 2 months after transplantation. The onset of spermatogenesis was delayed, and there were lesions in both injected and sham-injected testes. Despite the effects of the surgery, elongated spermatids were present in one recipient testis 2 months after surgery. The results suggest that, after modifying the surgical and transduction techniques, this approach will be a means to produce good colonization by donor spermatogonia in sheep testes.     

Development of a bioacoustic sensor for the early detection of Red Palm Weevil (Rhynchophorus ferrugineus Olivier)

The Red Palm Weevil (Rhynchophorus ferrugineus Olivier) is one of the worst pests for palms, since it can completely destroy the plant. Its early detection is very difficult and when the action of the pest is discovered, normally it is too late for recovering the plant. Bioacoustic sensors provide a good alternative for early detection of this pest because larvae activity is audible while they excavate tunnels to feed. This work describes the different stages for the development of an original electronic device based on acoustic sensors for early detection of Red Palm Weevil larvae in the interior of palms. This device is based on characteristic frequencies possibly related to their feeding activity. The performed tests have demonstrated that is possible to detect two week old larvae activity studying the sound intensity around 2250 Hz in palms infested only with 5 individuals under controlled environmental conditions. The activity of other insects artificially situated in the interior of palms did not affect the response of the device, possibly because they produce different frequencies (in the range 5–7 kHz). Future work will be aimed at assessing the infestation levels.