Genetic diversity of standard leaf nutrients in Coffea canephora genotypes during phenological phases.

Diagnosing foliar nutritional status is essential for fertilizer recommendations and for the identification of nutrient imbalances. This study aimed to verify genetic diversity and establish mean standards (leaf nutrient contents; LNCs) and relationships among leaf nutrients (LNC relationships; LNCRs) in seven conilon coffee genotypes during both pre-flowering and bean-filling stages. Twenty crops from several cities in the northern region of Espírito Santo State, Brazil, with crop yield either equal to or greater than 100 bags per hectare (during two harvests) were assessed. A total of 140 samples were collected during each evaluation period for quantification of leaf nutrient contents (N, P, K, Ca, Mg, S, Fe, Zn, Cu, Mn, and B). The Ward procedure, a hierarchical genetic clustering method, was used to quantify the genetic diversity among genotypes. To examine differences between the LNCs and LNCRs, F-and Scott-Knott tests were used. LNCs and LNCRs showed significant differences among the conilon coffee genotypes during the evaluation periods. Additionally, the 8V, 10V,and 12V genotypes exhibited the highest values for most of the nutrients, especially for N, P, and Cu. Therefore, the clustering method revealed genetic diversity among genotypes for standard leaf nutrient levels, implying that leaf diagnosis could be specific to each genotype and phenological stage.

Investigation of ground- and excited-state photophysical properties of 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin with ruthenium outlying complexes.

The present work employs a set of complementary techniques to investigate the influence of outlying Ru(II) groups on the ground- and excited-state photophysical properties of free-base tetrapyridyl porphyrin (H(2)TPyP). Single pulse and pulse train Z-scan techniques used in association with laser flash photolysis, absorbance and fluorescence spectroscopy, and fluorescence decay measurements, allowed us to conclude that the presence of outlying Ru(II) groups causes significant changes on both electronic structure and vibrational properties of porphyrin. Such modifications take place mainly due to the activation of nonradiative decay channels responsible for the emission quenching, as well as by favoring some vibrational modes in the light absorption process. It is also observed that, differently from what happens when the Ru(II) is placed at the center of the macrocycle, the peripheral groups cause an increase of the intersystem crossing processes, probably due to the structural distortion of the ring that implies a worse spin-orbit coupling, responsible for the intersystem crossing mechanism.

Agricultural sciences and education in the 21st century.

Rapid, ever-accelerating changes in science and technology will make current educational knowledge and systems obsolete as quickly as we reinvent them. Changes in demographics in our nation and changes in international trade will require us to encourage participation by all Americans, regardless of race or gender. Historically, change in higher education has faced strong resistance, but the establishment of the Land-Grant University system, the G.I. Bill, and other changes have encouraged participation by new groups of Americans. In order to take full advantage of all of the talent necessary to address the needs of a changing world, animal science departments and agricultural colleges must seek new partnerships to enhance recruitment of people from diverse groups, ensure that courses and curricula address the future, and encourage and promote women and minority faculty. Members of the American Society of Animal Science should continue to lead such changes.

[Hemorrhagic angiodysplasia of the upper digestive tract: endoscopic diagnosis and treatment]. / Angiodisplasia hemorrágica no trato digestivo superior: diagnóstico e tratamento endoscópico.

Angiodysplasia of the gastrointestinal (GI) tract is considered probably the most common cause of the occult bleeding. This paper analyses retrospectively 8 patients with angiodysplasia from upper GI tract. Two of them had Rendu-Osler-Weber syndrome. The main symptom was upper GI bleeding and 5 patients had acute melena and 3 chronic-intermittent bleeding. The diagnosis of angiodysplasia was confirmed by endoscopy. All patients but one underwent endoscopic treatment by injections of sclerosant and vasoconstrictor agents. One patient had hemigastrectomy and died in the post-operative. In the follow-up of 10 to 41 months, 2 patients died, one with bronchial carcinoma and the other due to cardiopulmonary failure. There was no bleeding recurrence in 5 patients. The endoscopic therapy should be the first choice if it is feasible, considering its efficacy as well as the low cost and safety.

Influence of experimental cryptorchidism on cholesterol side-chain cleavage enzyme and delta5-3beta-hydroxysteroid dehydrogenase activities in rat testes.

Testicular cholesterol side-chain cleavage enzyme (CSCCE) and delta5-3beta-hydroxysteroid dehydrogenase (delta5-3beta-HSD) activities were assessed 12 hours and 2, 4, 8, 16, and 32 days after surgical induction of bilateral cryptorchidism in adult rats. Within 12 hours after surgery CSCCE activity (expressed as dpm of isocaproic acid-14C formed from cholesterol-26-14C/3 hours/testis) was significantly reduced (P less than 0.01) in cryptorchid testes to approximately 55% of sham-operated control values and remained depressed at less than 50% of control activities 2, 4, 16, and 32 days after surgery. Cryptorchid testis delta5-3beta-HSD activity (measured by a pregnenolone substrate-depletion assay and expressed as mumoles of products/30 minutes/testis) did not differ from controls (P greater than 0.05) 1/2, 2, or 4 days after translocation of testes to the abdominal cavity. By day 8 of cryptorchidism, however, delta5-3beta-HSD activity was reduced to 60% of control values (P less than 0.05) and continued to decline to approximately 30% of controls during the remainder of the experimental period. These observed alterations in enzyme activities suggest an impairment in the ability of cryptorchid rat testes to synthesize androgens and further indicate that testicular CSCCE is more acutely sensitive to the cryptorchid milieu than delta5-3beta-HSD.

Effect of unilateral and bilateral castration and cryptorchidism on serum gonadotrophins in the rat.

The effects of unilateral and bilateral cryptorchidism and castration on serum concentrations of testosterone, FSH and LH in adult male rats were examined. The results provide no evidence for compensatory growth or development of the remaining scrotal testes up to 32 days after unilateral castration, although the scrotal testis of unilaterally cryptorchid rats showed enlargement when compared with those of control rats (P less than 0 - 05) at 32 days. Unilateral treatments had few significant effects on serum hormones, but testosterone was increased on day 4 (P less than 0 - 05) in unilaterally cryptorchid rats and on day 32 (P less than 0 - 05) in unilaterally castrated rats, compared with controls, and FSH levels were higher in unilaterally castrated rats on day 16 (P less than 0 - 05). Bilateral cryptorchidism caused an increase in serum FSH within 4 days (P less than 0 - 05) and in serum LH by 8 days (P less than 0-05) after surgery, with both hormones reaching levels double those found in control rats (P less than 0 - 01) by day 16, while testosterone levels were maintained at or above control values. Bilateral castration resulted in a marked decrease in testosterone levels (P less than 0 - 01) and a sharp increase in serum gonadotrophins. FSH had nearly doubled (P less than 0 - 01) and LH had increased fourfold (P less than 0 - 01) 4 days after castration, their levels reaching 773% (LH) and 287% (FSH) of control values by 32 days (P less than 0 - 01). The observations support the hypothesis of a separate, testosterone-independent feedback system of the testis on the hypophysis.

Comparative ability of rat seminiferous tubules, interstitium, and whole testes to utilize cholesterol-1,5-3H as a substrate for testosterone synthesis and the intratesticular distribution of cholesterol side-chain cleavage enzyme.

Homogenates of rat seminiferous tubules, interstitium and intact testis tissues were assessed for their ability to convert cholesterol -1,2-3H to testosterone in vitro. While 3H-testosterone synthesis was observed in incubates of interstitial and whole testis homogenates, no synthesis was detectable in homogenates of seminiferous tubules. To determine whether cholesterol side-chain cleavage enzyme (CSCCE) was deficient or absent in tubules, mitochondria from tubules, interstitium and whole testes were analyzed for CSCCE activity by measuring conversion of cholesterol -26-14C to 14C-isocaproate (+pregnenolone). Interstitial mitochondrial preparations from each of six testes were found to be approximately 200 times more active in CSCCE than the corresponding tubule mitochondria, and 1600-1800 times more active on a specific activity basis. Although caution is required in extrapolation of in vitro data to the in vivo state, these findings suggest rat seminiferous tubules may be incapable of de novo testosterone biosynthesis and that this lack of synthetic ability may be due to a deficiency of CSCCE.

The effect of artificial cryptorchidism on serum oestrogen and testosterone levels in the adult male rat.

Oestrone, oestradiol and testosterone levels were measured by radioimmunoassay in male rats 0.5, 1, 4, 8 and 16 days after rats were either made artifically cryptorchid or sham-operated. Oestradiol levels were not significantly different between cryptorchid and control rats 12 h or 1 day after surgery, but levels in cryptorchid animals fell to 35% of controls on day 4 (P less than 0.05), 31% on day 8, and 29% on day 16 (P less than 0.01). Conversely, oestrone and the total of the two oestrogens was higher in cryptorchid rats at one-half day (P less than 0.05), but did not differ at any other time. Testosterone levels were generally lower in cryptorchid rats than in controls. The minor contribution of oestradiol to total oestrogen levels and the lack of change of total oestrogens in cryptorchid rats led to the conclusion that oestrogens are probably not the tubular regulator of FSH in the male.