Two SCARECROW-LIKE genes are induced in response to exogenous auxin in rooting-competent cuttings of distantly related forest species

We characterized SCARECROW-LIKE genes induced by auxin in rooting-competent cuttings of two distantly related forest species (Pinus radiata D. Don and Castanea sativa Mill.) before the activation of cell division that results in adventitious root formation. The predicted protein sequences contain domains characteristic of the GRAS protein family and show a strong similarity to the SCARECROW-LIKE proteins, indicating conserved functions of these proteins. Quantitative RT-PCR analysis showed that these genes are expressed at relatively high levels in roots. Induction of increased mRNA levels in rooting-competent cuttings of both species in response to exogenous auxin was observed within the first 24 h of the root induction process, a time when cell reorganization takes place, but before the resumption of cell division and the appearance of adventitious root primordia. These results suggest that SCARECROW-LIKE genes play a role during the earliest stages of adventitious root formation.     

Dietary N-carbamylglutamate or L-arginine improves fetal intestinal amino acid profiles during intrauterine growth restriction in undernourished ewes

Our previous studies demonstrated that prenatal in utero growth restriction impairs postnatal intestinal function.Thus,improving postpartal intestinal absorption capacity and growth by manipulating the maternal diet prepartum is of importance.This work was conducted to determine whether supplementation of N-carbamylglutamate(NCG)or rumen-protected L-arginine(RP-Arg)increased fetal intestinal amino acid(AA)profiles in intrauterine growth retardation(IUGR)fetuses.On d 35 of gestation,Hu ewes(n=32)carrying twin fetuses were randomized into 4 groups(8 ewes and 16 fetuses in each group),where diets were as follows:100%of nutrient requirements recommended by National Research Council(NRC,2007)(CON);50%of nutrient requirements recommended by NRC(2007)(RES);RES+RPArg(20 g/d),(RES+ARG);and RES+NCG(5 g/d),(RES+NCG).On d 110 of gestation,both fetal and maternal tissues were collected and weighed.Compared with RES,solute carrier family 1,member 5(SLC1A5)was upregulated(P<0.05)within fetal jejunum,duodenum and ileum when supplementing NCG and RP-Arg.Relative to RES,RP-Arg or NCG supplementation to RES resulted in upregulation(P<0.05)of peptide transporter 1 protein abundance within the fetal ileum.NCG or RP-Arg supplementation to RES also upregulated phosphorylated mechanistic target of rapamycin(pmTOR)-to-mTOR ratio in the fetal ileum induced by IUGR(P<0.05).As a result,during IUGR,supplementation of Arg or NCG affected intestinal AA profiles in the fetus in part through controlling mTOR signal transduction as well as AA and peptide transport.Future studies should be conducted to understand the role(if any)of the placenta on the improvement of growth and AA profiles independent of the fetal intestine.This would help demonstrate the relative contribution of intestinal uptake in fetal life.     

Experimental evaluation of a composted seaweed extract as microalgal culture media

An organic culture media based on a composted liquid seaweed extract was developed and tested for growth of Chaetoceros muelleri. The extract was evaluated at two concentrations and then compared with two commercial media: Walne and agricultural fertilizer (AF). The concentrations of nitrogen and phosphorous differed between the two commercial media and the seaweed extract; however, growth of Chaetoceros muelleri was similar. The successful culture of Chaetoceros muelleri in composted liquid seaweed extract suggests the feasibility of and potential use for this natural, organic fertilizer in aquaculture. The seaweed extract is simple to obtain and inexpensive.     

Reproductive cycle of the rock oyster,Striostrea prismatica (Gray, 1825) from two locations on the southern coast of Ecuador

The reproductive cycle of the rock oyster Striostrea prismatica was determined at two fishing areas, General Villamil and Ayangue (located on the southern coast of Ecuador), between May 2012 and April 2013. Monthly sampling campaigns were performed at both locations. The tissues were histologically examined to determine gonadal index (GI), oocyte development, follicular area coverage and sex ratio. Surface seawater temperature, salinity and chlorophyll a concentration were measured during samplings. Our results show a similar annual reproductive pattern at both locations. The GI reached maximum values during the summer. Oysters reached highest ripeness in January and February, while spawning occurred in February–March. Gametogenesis was linked to a consistently increasing follicular area (from 1.3 ± 0.7% to 85.8 ± 7.8%) and associated to surface seawater temperature. Spawning coincided with warm water temperature fluctuations and a seawater salinity decrease. No correlation was found with Chlorophyll a concentration. The sex ratio of sampled populations was 1:1, suggesting that oysters sizing more than 10 cm in shell length present a stable sex proportion in the population. The diameter of mature oocytes was significantly reduced (32.7%) during histologically preparations in comparison to fresh oocytes. Our study provides useful information of environmental factors that may control the observed gametogenesis and spawning activity of S. prismatica.     

Maternal body condition during late-pregnancy is associated with in utero development and neonatal growth of Holstein calves

Background: Nutritional management in the dry period can alter body condition score(BCS) in dairy cows, a subjective measure of body fat. As such, differences in BCS during late-pregnancy not only mirror nutrient utilization by fat depots, but also can play important roles on the metabolic and hormonal environment. We investigated the association between cow BCS during late-pregnancy on developmental parameters and blood variables of neonatal calves. Forty-nine multiparous Holstein cows were retrospectively divided by prepartal BCS into normal BCS ≤3.25(NormBCS; 3.02 ± 0.17, n = 30) or high BCS ≥3.75(HighBCS; 3.83 ± 0.15, n = 19) groups.Plasma samples were collected from cows at-10 d relative to parturition. Body weight, hip and wither height, hip width and body length were measured at birth and weekly through weaning(42 d of age) and until 9 weeks of age. Calf blood samples were collected from the jugular vein at birth(before receiving colostrum, 0 d), 24 h after first colostrum and at 7, 21, 42 and 50 d of age. The data were subjected to ANOVA using the mixed procedure of SAS. The statistical model included day, BCS, and their interactions.Results: Dry matter intake(kg/d or % of body weight) during the last 4 weeks of pregnancy was lower(P ≤ 0.06) in HighBCS cows. Plasma concentrations of fatty acids, ceruloplasmin, and nitric oxide were greater overall(P 0.05) at d-10 prior to calving in HighBCS cows, and they tended(P = 0.08) to have greater concentrations of reactive oxygen metabolites. Birth body weight was lower(P = 0.03) in calves born to dams with HighBCS. In addition,plasma concentrations of fatty acids, albumin and urea(P 0.05) were greater in those calves. Although calves born to cows with HighBCS maintained a lower postnatal body weight(P = 0.04), hip and wither height, hip width, and body length, there was no difference(P 0.05) in daily starter intake and average daily gain due to maternal BCS.Conclusions: Overall, results highlight an association between BCS during late-gestation on in utero calf development and postnatal growth. A high maternal BCS during late-gestation was associated with lower calf body weights, which could be due to lower maternal intakes and a state of inflammation and metabolic stress.     

Prominent role of invasive species in avian biodiversity loss

The rise of extinction rates associated with human activities has led to a growing interest in identifying extinction-prone taxa and extinction-promoting drivers. Previous work has identified habitat alterations and invasive species as the major drivers of recent bird extinctions. Here, we extend this work to ask how these human-driven impacts differentially affect extinction-prone taxa, and if any specific driver promotes taxonomic homogenization of avifauna. Like most previous studies, our analysis is based on global information of extinction drivers affecting threatened and extinct bird species from the IUCN Red List. Unlike previous studies, we employ a multivariate statistical framework that allows us to identify the main gradients of variation in extinction drivers. By using these gradients, we show that bird families with the highest extinction risk are primarily associated with threats posed by invasive species, once species richness and phylogeny are taken into account. As expected, the negative impact of invasive species was higher on island species, but our results also showed that it was particularly high in those species with small distribution ranges. On the other hand, mainland species and island species with large ranges tended to be affected by habitat destruction. Thus the impacts of invasive species promote the process of taxonomic homogenization among islands and between islands and continents. Consequently, introduced species may increase biotic homogenization not only directly, as generally believed, but also indirectly through their disproportional impact on endemic species imperilment.     

Preliminary Analysis of the Results of Selective Therapy Against Strongyles in Pasturing Horses

Control of horse parasites often omits application of measures to eradicate the free-living stages in pastures and frequently relies on chemotherapy only. Selective therapy was used for Spanish Sport horses grazing either in the same pasture (continuous) or in rotated meadows. In each group, equines exceeding a cutoff value of 300 strongyle eggs per gram of feces received ivermectin or moxidectin. Efficacy of the treatment was assessed by estimating reduction of fecal egg counts and the number of horses shedding parasite eggs (PHR). Coprocultures revealed presence of the cyathostomins Cyathostomum and Gyalocephalus spp. In all treated groups, a 100% value for both reduction of fecal egg counts and PHR against cyathostomins was obtained, and PHR values ranged from 100% to 12%. The longest strongyle egg reappearance period was observed in horses undergoing rotation grazing and receiving ivermectin (9 weeks), compared with a 6-week period recorded for the other treated equines. Our results seem to point that the efficacy of selective therapy in equine herds could be reduced if the horses with fecal egg counts below the threshold value (thus not receiving chemotherapy) remain grazing in the same pastures with the treated ones. It is strongly suggested that interested parties consider performing periodic fecal analyses to monitor fecal egg counts, together with the percentage of horses passing eggs in feces, to improve the effect of this procedure.