Leaf pubescence: effects on absorptance and photosynthesis in a desert shrub

The presence of leaf pubescence (leaf hairs) in Encelia farinosa, a desert species of the Composite family, reduces the absorptance of photosynthetically active radiation (400 to 700 nanometers) by as much as 56 percent more than a closely related but nonpubescent species, E. californica, a native of the relatively moist southern California coast. Pubescence in E. farinosa, which increases through the growing season, modifies the leaf energy balance and dramatically reduces the photosynthetic rate. The reduction in the photosynthetic rate is caused by decreased light absorption rather than decreased carbon dioxide conductance through the boundary layer.     

Protein and energy utilization of boiled rice-legume diets and boiled cereals in growing rats

In growing rats, boiled milled rice-legume diets (2:1 N ratio) had lower energy digestigibility than boiled milled rice and equal if not better true digestibility, biological value, and net protein utilization (NPU). Rice-soybean diets showed better NPU than the other rice-legume diets. Boiled whole-grain corn and sorghum had lower digstible energy and NPU than boiled milled rice. NPU of the diets did not follow strictly the trend of the amino acid score of the diets; phenol (tannin) content reduced energy and protein digestibility of all diets, but sugars reduced energy and protein digestibilities of rice-legume diets only.     

The nutritional value of high-lysine barley genotypes

The protein quality of some improved high-lysine barley genotypes was measured chemically — including amino acid analyses and sequential protein extraction — and biologically in N-balance experiments with growing rats. The increased content of lysine, mainly due to an enhancement of the glutelin protein fraction, and other essential amino acids improved the nutritional quality as the biological value of the protein was significantly higher in the high-lysine material compared to normal. This improvement is undoubtedly of importance to meet the essential amino acid requirement of man as well as monogastric animals.     

Biological and technical notes on spraying against potato blight

Summary The numerical ratio of the deposits of sporangia of the blight fungus on the upper and lower leaf surfaces was found to vary between 10 and 30 depending on the stage of the attack and the position of the leaves. The ratio of infections on the upper and lower leaf surfaces had lower values than would be expected from the sporangia deposits. At weak attack 7–8 and at heavy attack 3–4 as many infections occurred on the upper surfaces In field trials the protection of spraying only from above was found to be on the average equally good as combined sparying from above and from below. However, some potato varieties with an open type of growth (King Edward) were somewhat better protected by spraying from above, while combined spraying gave somewhat better results in varieties with a closed type of growth (Bintje). In laboratory trials with different droplet sizes on detached leaflets the smallest droplets of Bordeaux tested (M.M.D. 55μ) gave considerably better protection against infection than larger droplets. Articificial rain treatment of Bordeaux-sprayed leaves clearly improved an incomplete protection presumably through redistribution of fungicidal particles to unprotected leaf areas. Similar trials with Zineb gave more irregular results; in most cases rain deteriorated the protection.

---

Zusammenfassung Das zahlenm?ssige Verh?ltnis der Depositionen von Sporangien desPhytophthorapilzes auf der Oberseite und Unterseite der Bl?tter erwies sich als schwankend zwischen 10 und 30, je nach Stadium des Befalls und Stellung der Bl?tter. Das Verh?ltnis der Infektionen auf der Oberseite und Unterseite der Bl?tter zeigte geringere Werte, als von den Sporangiendepositionen zu erwarten w?re. Bei schwachem Befall kamen 7–8 und bei starkem Befall nur 3–4 mehr Infektionen auf der Blattoberseite vor. Bei Feldversuchen ergab sich, dass der Schutz durch Spritzen „nur von oben” im allgemeinen ebenso gut war wie das kombinierte Spritzen „von oben und von unten”. Jedoch wurden einige Kartoffelsorte mit offenem Wuchs des Krautes (King Edward) etwas besser geschützt durch oberseitiges Spritzen, w?hrend das kombinierte Spritzen etwas bessere Ergebnisse zeigte bei Sorten mit geschlossenem Krautwuchs (Bintje). Bei Laboratoriumversuchen mit verschiedenen Tropfengr?ssen auf abgetrennten Bl?ttchen ergaben die kleinsten Tr?pfchen Bordeaux (Kupferkalkbrühe M.M.D. 55μ) einen bedeutend besseren Schutz gegen Infektion als die gr?sseren Tropfen. Künstlicher Regen auf den mit Bordeaux bespritzten Bl?ttchen verbesserte deutlich einen unvollst?ndigen Schutz, vermutlich durch die Neuverteilung der Partikelchen des Fungizids über die ungeschützten Blattstellen. Gleichartige Versuche mit Zineb ergaben mehr unregelm?ssige Resultate; in den meisten F?llen verschlechterte Regen den Schutz.

---

Resumé Il appert que la proportion numérique des dép?ts de sporanges du champignon du mildiou sur les surfaces supérieures et inférieures des feuilles varie entre 10 et 30, ceci en fonction des attaques plus ou moins sérieuses et de la position des feuilles. La proportion des infestations sur les surfaces supérieures et inférieures des feuilles a démontré des valeurs plus basses que les dép?ts de sporanges laissaient prévoir. Les surfaces supérieures des feuilles ont démontré, devant une attaque faible, 7 à 8 fois plus d'infestations, et, en présence d'une attaque sérieuse 3 à 4 fois plus d'infestations que les surfaces inférieures. Dans des essais entrepris en plein champ la protection par voie de pulvérisation des surfaces supérieures des feuilles était, en moyenne, aussi efficase que lorsque les feuilles furent pulvérisées des c?tés supérieur et inférieur. Toutefois, certaines variétés de pommes de terre d'une croissance étalée (King Edward par exemple) furent un peu mieux protégées par la pulvérisation de la surface supérieure des feuilles, alors qu'une pulvérisation combinée des c?tés supérieur et inférieur a donné des résultats légèrement meilleurs chez les variétés ayant un type de croissance fermée (Bintje). Dans des essais entrepris en laboratoire avec diverses grosseurs de gouttelettes sur des feuilles détachées de la plante, les gouttelettes les plus petites de bouillie bordelaise (M.M.D. 55μ) ont donné une protection nettement meilleure contre l'infestation que les gouttelettes plus grosses. Le traitement par pluie artificielle de feuilles pulvérisées par bouillie bordelaise a sensiblement amélioré la protection incomplète du fait probablement d'un redistribution des particules du fongicide appliqué sur les parties de la feuille restées non-protégées jusque-là. Desessaissimilaires avec Zineb ont donné des résultats plus irréguliers; dans la majorité des cas la pluie a corrompu l'efficacité de la protection.

---

---

Lecture held at the 4th International Informal Potato Conference at Lund (Sw.), August 1957.     

Affinity and rate constants for interactions of bovine folate-binding protein and folate derivatives determined by optical biosensor technology. Effect of stereoselectivity

The interactions between bovine folate-binding protein (FBP) and different folate derivatives in pure diastereoisomeric forms were studied at pH 7.4 by a surface plasmon resonance technology (Biacore). The results show that folic acid had the most rapid association rate (k(a) = 1.0 x 10(6) M(-)(1) s(-)(1)), whereas (6S)-5-HCO-5,6,7,8-tetrahydrofolic acid had the most rapid dissociation rate (k(d) = 3.2 x l0(-)(3) s(-)(1)). The equilibrium dissociation constant (K(D)), calculated from the quotient of k(d)/k(a), showed that the two forms of folates not occurring in nature, that is, folic acid and (6R)-5-CH(3)-5,6,7,8-tetrahydrofolic acid, had the highest affinities for FBP, 20 and 160 pmol/L, respectively. The results thus show that there were great differences in the interactions between folate-binding protein and the major forms of folate derivatives. The nutritional implications of these differences are discussed.     

Bru1 gene and potential alternative sources of resistance to sugarcane brown rust disease

Brown rust, caused by the fungus Puccinia melanocephala, is responsible for important yield losses in sugarcane production globally and it is therefore an important objective to introduce resistance to this disease in breeding programs. A major gene, Bru1, has been shown to confer resistance to P. melanocephala strains from different parts of the world and two molecular markers, R12H16 and 9O20-F4, closely associated to this gene have been previously reported. The usefulness of these molecular diagnostic markers in order to predict a rust resistant phenotype under natural high pressure inoculums conditions was analyzed. A total of 129 sugarcane accessions were evaluated under field infection for resistance or susceptibility to brown rust and subsequently screened for presence or absence of the two Bru1 diagnostic markers. A total of 49 genotypes (38 %) were phenotyped as resistant to brown rust but only eight (16.3 %) of them were harboring the Bru1 gene. To determine overall frequency of the Bru1 in the local sugarcane germplasm collection, 190 additional genotypes were examined. Presence of Bru1, as determined by the diagnostic markers, was detected in only 7 % of the genotypes evaluated. In conclusion, Bru1 diagnostic markers enable positive selection for brown rust resistance in sugarcane and moreover allowed detecting at least one additional source(s) of resistance. Interestingly, whilst only little genetic variability of rust resistance independent of Bru1 has been reported previously, this alternative genetic resource(s) found in our local germplasm constitutes the predominant one and should be helpful in order to amplify the narrow genetic basis for brown rust resistance in sugarcane.     

Effect of Environmental Temperature on Digestive Tract,Visceral Organ Size,Digestibility and Energy Metabolism in Rats Fed Different Levels of Pea Fibre

Abstract

A study was performed to investigate the effect of environmental temperature (18°C or 28°C) and increasing levels of pea fibre in the diet on digestive tract, visceral organ size, digestibility and energy metabolism in rats. Thirty-six male Wistar rats, initial liveweight (LW) 77-79 g, were allocated to six groups and housed at either 18°C (three groups) or 28°C (three groups). Three wheat starch, fish meal and pea fibre-based diets were prepared to contain 100, 200 and 300 g pea fibre kg^?1 (68, 110 and 157 g dietary fibre kg^?1 DM) and 160 g protein (N × 6.25) kg^?1. One group of rats at each temperature was fed one of the diets for four balance periods. Gas-exchange measurements were made and urine and faeces were quantitatively collected. Food to gain ratio was higher (P <.05) at 18°C than at 28°C and increased (P <.05) as the level of fibre was increased. The weight of the visceral organs from rats housed at 18°C was higher (P<.05) than at 28°C. The empty weight of the small intestine, caecum and colon increased (P <.05) as the level of pea fibre was increased. The digestibility of DM, protein and dietary fibre (DF) was lower (P <.05) at 18°C than at 28°C. As the level of pea fibre was increased, the digestibilities of nutrients and energy decreased (P <.05). However, the digestibility of DF increased (P <.05) as the level of pea fibre was increased. The partial digested energy value for pea fibre was 11.9 kJ g^?1. The metabolizable energy (ME) intake and heat production at 18°C (1128 and 974 kJ (W^0.75 day)^?1 respectively) were higher (P<.05) than at 28°C (831 and 674 kJ (W^0.75 day)^?1 respectively). As the level of pea fibre was increased, ME intake (W^0.75 day)^?1 and heat production (W^0.75 day)^?1 decreased (P <.05). Heat production as a percentage of ME was higher (P <.05) at 18°C than at 28°C: 86.6% and 81.2%, respectively. Heat production as a percentage of ME was higher (P <.05) for rats fed the 100 g pea fibre kg^?1 diet than the 200 or 300 g pea fibre kg^?1 diet. In conclusion, environmental temperature as well as DF influenced digestive tract and visceral organ size, digestion and protein and energy metabolism.     

Proof of concept for eradication of vancomycin resistant Enterococcus faecium from broiler farms

Background

Vancomycin resistant enterococci (VRE) in Swedish broiler production has been shown to persist at farms between batches. The aim of this study was therefore to determine the possibility to eliminate VRE by disinfection of compartments in broiler houses as a proof of concept.

Findings

VRE could not be detected in environmental samples from the disinfected test compartments in the broiler houses but was detected in environmental samples from the control compartments. The proportion of broilers colonized with VRE decreased in both the test and the control compartments.

Conclusions

The results are promising and show that the occurrence of VRE in broiler houses can be reduced by adequate cleaning and disinfection with a combination of steam and formaldehyde.     

Intervertebral disc disease in dogs – Part 2: Comparison of clinical,magnetic resonance imaging,and histological findings in 74 surgically treated dogs

The relationship between intervertebral disc (IVD) disease and IVD degeneration remains unclear. The aim of the present study was to compare the clinical severity of IVD herniation (IVDH), determined with a neurological grading system, with findings of magnetic resonance imaging (MRI) and histology using grading systems for IVD degeneration in chondrodystrophic (CD; n = 37) and non-chondrodystrophic (NCD; n = 37) dogs. This study is the second part of a two-part investigation, where the first part involved the development and validation of a histological grading scheme for classification of canine IVD degeneration.IVD degeneration graded on MRI correlated significantly with IVD degeneration graded on histology, but not with pre-operative clinical signs. Hansen type 1 hernias were more common in the cervical and thoracolumbar segments and Hansen type 2 hernias were more common in the lumbosacral segment. Type 1 hernias occurred more often in CD dogs than in NCD dogs, and CD dogs were clinically more severely affected than NCD dogs. The grade of IVD degeneration on MRI was higher in CD dogs than in NCD dogs, but there was no difference between dogs with type 1 and type 2 hernias. No significant differences in histological grade were found between CD and NCD dogs or between type 1 and type 2 hernias.It was possible to conclude that IVD degeneration did not correlate with the neurological severity of IVDH. The extent of degeneration identified on MRI correlated with degeneration seen histologically. Although the MRI grading system reflected the severity of IVD degenerative changes as confirmed by histopathology, it appeared less useful in predicting the clinical implications.     

Genetic diversity and gene flow in six accessions of Meso-America teosintes

The genus Zea (teosinte) has a native distribution from Mexico to Nicaragua (Meso-America region) and studies on teosinte species may help improve our understanding of maize genetics, population genetics, genome evolution and crop evolution. Moreover, since F1 hybrids between teosinte and maize are fertile, all teosinte species can potentially contribute to maize breeding in the form of traits such as resistance or tolerance to heavy metals in the soil and other adverse environmental conditions. Gene flow between maize and teosinte occurs in Mexico and Central America. This study analysed the genetic diversity of teosintes by using the microsatellite technique on a total of 120 individuals from six different species and 21 Simple Sequence Repeats (SSR). A total of 109 alleles were found and the number of alleles per locus ranged from 2 to 7. The genetic diversity varied between all species from 0.514 to 0.572, with a mean value of 0.548 (Nei index). Rare and unique alleles were detected in all species, with the highest frequencies found in Zea diploperennis Iltis, Doebley et Guzman, Zea perennis (Hitchc.) Reeves et Mangelsdorf and Zea nicaraguensis Iltis et Benz, which had more than seven rare alleles each. Analysis of molecular variance revealed that 19.87% of the variation between species was statistically significant (P < 0.001). When the different species were compared with the Wright (Fst) value, genetic variation between species was confirmed. The data also revealed a moderate rate gene flow between the species. Genetic diversity was found to be somewhat higher in Central America than in Mexico.