Understanding of microbial communities inhabiting cattle vaginal tract may lead to a better comprehension of bovine physiology and reproductive health being of great economic interest. Up to date, studies involving cattle microbiota are focused on the gastrointestinal tract, and little is known about the vaginal microbiota. This study aimed to investigate the vaginal microbiome in Nellore cattle, heifers and cows, pregnant and non-pregnant, using a culture independent approach. The main bacterial phyla found were Firmicutes (~40–50%), Bacteroidetes (~15–25%) and Proteobacteria (~5–25%), in addition to ~10–20% of non-classified bacteria. 45–55% of the samples were represented by only ten OTUs: Aeribacillus, Bacteroides, Clostridium, Ruminococcus, Rikenella, Alistipes, Bacillus, Eubacterium, Prevotella and non-classified bacteria. Interestingly, microbiota from all 20 animals could be grouped according to the respiratory metabolism of the main OTUs found, creating three groups of vaginal microbiota in cattle. Archaeal samples were dominated by the Methanobrevibacter genus (Euryarchaeota, ~55–70%). Ascomycota was the main fungal phylum (~80–95%) and Mycosphaerella the most abundant genus (~70–85%). Hormonal influence was not clear, but a tendency for the reduction of bacterial and increase of archaeal populations in pregnant animals was observed. Eukaryotes did not vary significantly between pregnant and non-pregnant animals, but tended to be more abundant on cows than on heifers. The present work describes a great microbial variability in the vaginal community among the evaluated animals and groups (heifers and cows, pregnant and non-pregnant), which is significantly different from the findings previously reported using culture dependent methods, pointing out the need for further studies on this issue. The microbiome found also indicates that the vaginal colonization appears to be influenced by the gastrointestinal community.

To assess the role of central dopamine on metabolic rate, heat balance and running performance, 2.0 microL of 5 x 10(-3)M dopamine solution (DA) or 0.15M NaCl (SAL) was intracerebroventricularly injected in Wistar rats 1 min before running on a motor-driven treadmill, according to a graded exercise protocol, until fatigue. Oxygen consumption (VO(2)) and body temperature (T(b)) were recorded at rest, during exercise, and after 30 min of recovery. DA induced a marked increase in workload (approximately 45%, p<0.05). At fatigue point, DA-injected rats attained approximately 29% higher maximum oxygen consumption (VO(2max)) and approximately 0.75 degrees C higher T(b) than SAL-injected rats. Despite the higher VO(2max) and T(b) attained during exercise, DA-treated rats reached VO(2) basal values within the same recovery period and dissipated heat approximately 33% faster than SAL-treated rats (p<0.05). The mechanical efficiency loss rate was approximately 40% lower in DA than in SAL-treated rats (p<0.05), however, the heat storage was approximately 35% higher in the DA group (p<0.05). Our results demonstrate that increased DA availability in the brain has a performance-enhancing effect, which is mediated by improvements in the tolerance to heat storage and increases in the metabolic rate induced by graded exercise. These data provide further evidence that central activation of dopaminergic pathways plays an important role in exercise performance.

Phosphate fertilization is a common practice in agriculture worldwide, and several commercial products are widely used. Triple superphosphate (TSP) is an excellent soluble phosphorus (P) source. However, its high cost of production makes the long-term use of crude rock phosphate (RP) a more attractive alternative in developing countries, albeit its influence on plant-associated microbiota remains unclear. Here, we compared long-term effects of TSP and RP fertilization on the structure of maize rhizosphere microbial community using next generation sequencing. Proteobacteria were dominant in all conditions, whereas Oxalobacteraceae (mainly Massilia and Herbaspirillum) was enriched in the RP-amended soil. Klebsiella was the second most abundant taxon in the RP-treated soil. Burkholderia sp. and Bacillus sp. were enriched in the RP-amended soil when compared to the TSP-treated soil. Regarding fungi, Glomeromycota showed highest abundance in RP-amended soils, and the main genera were Scutellospora and Racocetra. These taxa are already described as important for P solubilization/acquisition in RP-fertilized soil. Maize grown on TSP and RP-treated soil presented similar productivity, and a positive correlation was detected for P content and the microbial community of the soils. The results suggest changes of the microbial community composition associated to the type of phosphate fertilization. Whilst it is not possible to establish causality relations, our data highlights a few candidate taxa that could be involved in RP solubilization and plant growth promotion. Moreover, this can represent a shorter path for further studies aiming the isolation and validation of the taxa described here concerning P release on the soil plant system and their use as bioinoculants.

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Our results show that central fatigue due to hyperthermia and increased body heating rate induced by central Ang II AT1 receptor blockade in exercising rats is related with higher 5-HT content in the preoptic area and hypothalamus as well as with decreased levels of this neurotransmitter in the hippocampus. Furthermore, the interaction between 5-HT and DA within the hypothalamus seems to contribute to hyperthermia and premature central fatigue after angiotensinergic inhibition.

The effect of central angiotensin AT 1-receptor blockade on thermoregulation in rats during exercise on a treadmill (18 m/min, 5% inclination) was investigated. Core (T b) and skin tail temperatures were measured in rats while they were exercising until fatigue after injection of 2 l of losartan (Los; 20 nmol, n ϭ 4; 30 nmol, n ϭ 4; 60 nmol, n ϭ 7), an angiotensin II AT 1-receptor antagonist, or 2 l of 0.15 mol/l NaCl (Sal; n ϭ 15) into the right lateral cerebral ventricle. Body heat rate (BHR), heat storage rate, threshold Tb for tail vasodilation (TTbV), time to fatigue, and workload were calculated. During exercise, the BHR and heat storage rate of Los-treated animals were, respectively, 40 and 53% higher (P Ͻ 0.01) than in Sal-treated animals. Additionally, rats injected with Los showed an increased TTbV (38.59 Ϯ 0.19°C for Los vs. 38.12 Ϯ 0.1°C for Sal, P Ͻ 0.02), a higher Tb at fatigue point (39.07 Ϯ 0.14°C Los vs. 38.66 Ϯ 0.07°C Sal, P Ͻ 0.01), and a reduced running performance (27.29 Ϯ 4.48 min Los vs. 52.47 Ϯ 6.67 min Sal, P Ͻ 0.01), which was closely related to the increased BHR. Our data suggest that AT1-receptor blockade attenuates heat dissipation during exercise due to the higher TTbV, leading to a faster exercise-induced increase in Tb, thus decreasing running performance. tail vasodilation; fatigue; heat balance ACTING CENTRALLY, ANGIOTENSIN II (ANG II), exerts thermoregulatory effects characterized by a decreased metabolic rate, a fall in core temperature (T b ), and an increase in tail skin temperature (T tail ) (43,44,46), through angiotensin type 1 (AT 1 ) receptors. These receptors are widely spread through the central nervous system (CNS), including the preoptic area/ anterior hypothalamus (POA/AH), regions of the hypothalamus considered to be the integrative centers of body temperature (5,29,34,35). In addition, the subfornical organ (SFO) is critical for the central actions of ANG II (8, 14). The AT 1 -receptor antagonist losartan (Los) has been used to investigate the role of ANG II in T b . Some studies have observed that intracerebroventricular (icv) injection of Los inhibited the hypothermic effect of ANG II, producing an increase in T b of resting animals exposed to a hot environment (7,27). In addition, Horowitz and colleagues (17,36) showed that central administration of Los elevates the temperature threshold for peripheral vasodilation and causes a downward shift in the threshold for evaporative cooling during heat stress, indicating the involvement of hypothalamic angiotensinergic signaling in thermoregulation. Because hypothermia and increased heat dissipation may be neuroprotective, activation of central angiotensinergic transmission may exert important effects on thermoregulation during exercise, influencing running performance.Elevated internal body temperature and increased heat storage (9, 12, 30) have been considered to be limiting factors that reduce the CNS drive for exercise performance (31,32,40) and precipitate feelings of fatigue, thus protecting the brain from ther...

The effects of increased brain availability of L-arginine (L-arg), a precursor for nitric oxide synthesis, on core body temperature (Tcore ) and cutaneous heat loss were evaluated in running rats. One week prior to the experiments, adult male Wistar rats received the following implants: a chronic guide cannula in the lateral cerebral ventricle and a temperature sensor in the abdominal cavity. On the day of the experiments, the rats were assigned to receive a 2-μL intracerebroventricular injection of either NaCl (0.15 mol/L) or L-arg solution (0.825, 1.65 or 3.30 mol/L); Tcore and tail skin temperature were measured while the rats ran at a speed of 18 m/min until they were fatigued. L-arginine induced a dose-dependent reduction in the threshold Tcore required for cutaneous heat loss (38.09 ± 0.20°C for 3.30-mol/L L-arg vs 38.61 ± 0.10°C for saline; P < 0.05), which attenuated the exercise-induced hyperthermia. Although the rats treated with L-arg presented a lower Tcore at the end of exercise (~0.7°C lower after treatment with the highest dose), no changes in the time to fatigue were observed relative to the control trial. These results suggest that brain L-arg controls heat loss during exercise, most likely by modulating the sympathetic vasoconstrictor tonus to skin vessels. Furthermore, despite facilitating cutaneous heat loss mechanisms, increased brain L-arg availability did not enhance physical performance.

Here, we describe the metagenome and functional composition of a microbial community in a historically metal-contaminated tropical freshwater stream sediment. The sediment was collected from the Mina Stream located in the Iron Quadrangle (Brazil), one of the world’s largest mining regions. Environmental DNA was extracted and was sequenced using SOLiD technology, and a total of 7.9 Gbp was produced. A taxonomic profile that was obtained by comparison to the Greengenes database revealed a complex microbial community with a dominance of Proteobacteria and Parvarcheota. Contigs were recruited by bacterial and archaeal genomes, especially Candidatus Nitrospira defluvii and Nitrosopumilus maritimus, and their presence implicated them in the process of N cycling in the Mina Stream sediment (MSS). Functional reconstruction revealed a large, diverse set of genes for ammonium assimilation and ammonification. These processes have been implicated in the maintenance of the N cycle and the health of the sediment. SEED subsystems functional annotation unveiled a high degree of diversity of metal resistance genes, suggesting that the prokaryotic community is adapted to metal contamination. Furthermore, a high metabolic diversity was detected in the MSS, suggesting that the historical arsenic contamination is no longer affecting the prokaryotic community. These results expand the current knowledge of the microbial taxonomic and functional composition of tropical metal-contaminated freshwater sediments.