Phosphorus Recovery from Phosphate Rocks Using Phosphate-Solubilizing Bacteria

In this paper, we are presenting a biological process to recover phosphorus by solubilizing low-grade phosphate rocks. To this end, the efficiency of different phosphate-solubilizing microorganism (PSM) species for solubilizing P from phosphate rocks using both pure cultures and associations. Nutritional conditions, phosphate rock concentrations, and reactor designs were tested. The genus Bacillus, especially Bacillus megaterium (ATCC 14581), was found to be the most promising PSM for solubilizing P. Production of organic acids and acidic pH values were shown to be directly related to P solubilizing. However, associations between tested microorganisms did not significantly enhance process efficiency. We conclude that nutritional factors of the medium are important to solubilization, and lower phosphate rock concentrations lead to better solubilization. The Air Lift reactor was promising for B. megaterium (ATCC 14581), but adaptations are needed for further tests.     

Feeding ecological knowledge: the underutilised power of faecal DNA approaches for carnivore diet analysis

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Sensible heat transfer and thermal windows in Dasyprocta leporina (Mammalia,Rodentia)

This study aimed to evaluate the diurnal variation of the sensible heat transfer in red-rumped agoutis (Dasyprocta leporina) bred in captivity in a semi-arid environment. In addition, we seek to identify thermal windows by infrared thermography during the daytime period (07:00, 09:00, 11:00, 14:00, and 16:00). The body surface temperature was higher in the pinna (36.84 ± 0.11 °C), followed by the hind limbs (36.55 ± 0.11 °C). These body regions were primarily responsible for heat loss by radiation (which was 10.13 ± 1.17 W m^?2 and 11.19 ± 1.17 W m^?2, respectively), and acted like biological thermal windows. Heat transfer by convection was more intense in the body trunk and hind limbs at all times of the day. Thus, sensible heat transfer is important for maintaining homeothermy in red-rumped agouti in hot environments. In conclusion, these rodents use specialized body regions (pinna and hind limbs) for heat transfer.     

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.     

Partitioning of gonococcal LPS into phenol and water: Different LPS composition of in vivo and in vitro selected variants

Abstract Depending on the culture conditions, Pyrodictium occultum cells revealed two different types of fibers with significant differences in their width in the electron microscope. During growth on elemental sulfur preferentially fibres with a diameter of about 23 nm (type I) were produced. When elemental sulfur was substituted by thiosulfate fibers with a diameter of around 15 nm (type II), were the main appendages. Both types form hollow cylinders consisting of helically arranged sub-units with a wall thickness of 2–3 nm. A triple- layered unit membrane could not be found.     

The embryo culture media in the era of epigenetics: is it time to go back to nature?

This review is intended to draw attention to the importance of the culture media composition on the health of the embryos, fetuses, newborns, and adults derived from assisted reproductive technologies (ART). Although current research and industry trends are to use chemically defined media because of their suitability for manufacturing, commercialization, and regulatory purposes, compelling evidence indicates that those media fail to adequately account for the biological demands of early embryogenesis. Here, we list the main undesirable consequences of the ART described in the literature and results we and others have obtained over the past decade exploring an alternative and more natural way to support embryo growth in vitro: inclusion of endogenous reproductive fluids as additives in the ART culture media for pigs, cows, and humans. This review systematically assesses the pros and cons of using reproductive fluid additives, as well as the requirements to implement this approach in the future.     

Heifer nutrition during early- and mid-pregnancy alters fetal growth trajectory and birth weight

Maternal nutrient intake during gestation can alter fetal growth. Whilst this has been studied extensively in the sheep, less is known about effects in the bovine. Composite-breed beef heifers were allocated to either a high (H/? = 76 MJ metabolisable energy (ME) and 1.4 kg crude protein (CP)) or low (L/? = 62 MJ ME and 0.4 kg CP daily) nutritional treatment at artificial insemination. Half of each nutritional group changed to an opposite nutritional group at the end of the first trimester (?/H = 82 MJ ME and 1.4 kg CP; ?/L = 62 MJ ME and 0.4 kg CP daily), resulting in 4 treatment groups: HH (n = 16); HL (n = 19); LH (n = 17); LL (n = 19). During the third trimester all heifers were fed the same diets. Fetuses were measured at 4-weekly intervals beginning at day 39 of gestation. Calves were also measured at birth for physical body variables. Low maternal nutrient intake was associated with decreased crown-rump length at day 39 (P < 0.01) and increased thoracic diameter at day 95 (P < 0.01). Umbilical cord diameter was reduced in L/? fetuses in the first trimester (P < 0.05) but was greater in ?/L fetuses in the second trimester compared to their respective H counterparts (P < 0.05). Calf birth weight was decreased in association with ?/L maternal diets (P < 0.05). In conclusion, fetal development of cattle may be affected by maternal nutrition as early as day 39 of gestation. This may be followed by either compensatory fetal growth, or alternatively, preferential fetal tissue growth that is dependant upon maternal nutrition. Clearly, calf birth weight may be altered by maternal nutrition during mid-gestation.     

Physiological basis of reduced Al tolerance in ditelosomic lines of Chinese Spring wheat

Aluminum tolerance was assessed in the moderately Al-tolerant wheat (Triticum aestivum L.) cultivar Chinese Spring and a set of ditelosomic lines derived from Chinese Spring. Three ditelosomic lines lacking chromosome arms 4DL, 5AS and 7AS, respectively, exhibited decreased Al tolerance relative to the euploid parent Chinese Spring based on reduced root growth in Al-containing solutions. The physiological basis of the reduced Al tolerance was investigated. Measurements by inductively coupled argon plasma mass spectroscopy of root apical Al accumulation demonstrated that two of these three lines had a decreased ability to exclude Al from the root apex, the site of Al phytotoxicity. As Al-induced malate exudation has been suggested to be an important physiological mechanism of Al tolerance in wheat, this parameter was quantified and malate exudation was shown to be smaller in all three deletion lines compared with Chinese Spring. These results suggest that the decreased Al tolerance in at least two of the three ditelosomic lines is due to the loss of different genes independently influencing a single Al-tolerance mechanism, rather than to the loss of genes encoding alternative Al-tolerance mechanisms. Received: 3 July 2000 / Accepted: 9 August 2000     

Lectin histochemical localization of N- and O-linked oligosaccharides during the spermiogenesis of the urodele amphibian Pleurodeles waltl

The aim of this work is the characterization of the glycoconjugates of the spermatids during the spermiogenesis of the testis of an urodele amphibian, Pleurodeles waltl, by means of lectins in combination with several chemical and enzymatic procedures, in order to establish the distribution of N- and O-linked oligosaccharides in these cells. The acrosome was the most relevant lectin-labeled structure. The O-linked oligosaccharides contained DBA- and SBA-positive GalNAc, AAA-positive Fuc and PNA-positive Gal1,3GalNAc. Sialic acid was scarcely observed, the Neu5Ac2,-3Gal1,4GlcNAc sequence was found in N-linked oligosaccharides. Additionally, N-linked oligosaccharides containing HPA-positive GalNAc and AAA-positive Fuc were found. Moreover, with some lectins the acrosome showed a variable composition of the oligosaccharides in the different steps of the sperm maturation. Some residues were found only in the early steps in maturating acrosome, while others were in the later steps, showing that acrosomal glycoconjugates are modified during acrosome development in spermiogenesis. The changes observed during acrosome maturation suggest the existence of a predetermined pattern of storage of the acrosome components and a progressive compression of them.