Phenotypic and genotypic characterization of bovine mastitis isolates of Staphylococcus aureus for biofilm formation

Staphylococcus aureus is one of the most common pathogens responsible for contagious mastitis in ruminants. The ability of S. aureus to form biofilm in vivo is considered to be a major virulence factor influencing its pathogenesis in mastitis. The objectives of the study were to examine in vitro slime production, biofilm formation, and the presence of the ica gene locus and icaA and icaD genes in S. aureus isolates from bovine mastitis. Thirty-two of the 35 isolates tested produced slime on Congo red agar, whereas only 24 of the isolates were found to produce biofilm in vitro. However, all the 35 isolates possessed the ica locus, icaA and icaD genes. This study indicates a high prevalence of the ica genes among S. aureus mastitis isolates, and their presence is not always associated with in vitro formation of slime or biofilm. A combination of phenotypic and genotypic tests is recommended for investigating biofilm formation in S. aureus.     

Amino acid composition of single seeds and cotyledons of some brassica species by gas liquid chromatography

There are considerable differences in amino acid pattern between the seed coat and the embryo (separated after 5 h of imbibition in water) but only minor differences between the various embryonic parts, the hypocotyl, the inner and outer cotyledons. Thus, the seed coat is high in proline and hydroxyproline and relatively low in glutamic acid. No change in amino acid pattern was observed in the cotyledons after an additional 19 h of imbibition. This is of pratical significanse since a separation of the seed parts — of value in genetic studies — is greatly simplified if performed with swollen seeds as compared with dry seeds.The variation in the amino acid composition among single seeds of heterozygousB. campestris was higher than the variation among single seeds of homozygousB. tournfortii.

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Zusammenfassung Es bestehen bedeutende Unterschiede im Aminosäuremuster der Samenschale und des Embryos (getrennt nach 5 Stunden Inhibition in Wasser) aber nur geringere zwischen den verschiedenen Teilen des Embryos, dem Hypocotyl und den inneren und äusseren Cotyledonen. So sind die Gehalte der Samenschale hoch an Prolin und Hydroxyprolin sowie relativ niedrig an Glutaminsäure. Keine Anderung trat im Aminosäuren-Muster der Cotyledonen ein, wenn sie einer weiteren 19 Stunden-Inhibition unterworfen wurden. Dies ist von praktischer Bedeutung, da eine Trennung der Samenbestandteilewichtig für genetische Studien-im inhibierten Zustand sstärker vereinfacht wird als im normalen trockenen Zustand.Die Variation des Aminosäuren-Spektrums zwischen einzelnen Samen vonBrassica campestris-Heterozygoten war gröszer als die der Heterozygoten vonBrassica tournefortii.

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Résumé Il y a des différences considérables dans la composition en aminoacides entre le tégument séminal et l'embryon (séparé après 5h d'imbibition dans l'eau); par contre il y a peu de différences entre les diverses parties de l'embryon, l'hypocotyle, l'intérieur des cotylectons. Ainsi le tégument séminal est riche en proline et hydroxyproline, et relativement pauvre en acideglutamique. Aucun changement dans les taux d'amincides n'a été observé lors d'une imbibition supplémentaire de 19 heures.Ce fait a une importance pratique, car la séparation de la graine en ses diverses parties — importante dans les recherches génétiques — est grandement simplifiée si elle est pratiquée sur des graines gonflées et non sur des graines sèches. La variation du taux d'aminoacides entre graines isollées deB. campestris hétérozygote était plus grande que chez les graines homozygotes deB. tournefortii.

     

Literature review of an underutilized legume: Canavalia gladiata L.

The literature related to the legume commonly known as sword beans (Canavalia gladiata) that belongs to the genus Canavalia which is considered to be an underutilized legume, is reviewed. The legume seeds are considered to be a cheap source of good protein and calories that are easily available. However, even with this knowledge, the utilization of most legumes is apparently low. Sword beans have favorable agronomic features suitable for cultivation in the tropics and a high average yield comparable to that of soybeans. The agroclimatic conditions suitable for cultivation, morphological features, uses, chemical composition and the antinutritional factors of the plant are discussed.     

Inactivation of bacterial fish pathogens by medium-chain lipid molecules (caprylic acid, monocaprylin and sodium caprylate)

The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of caprylic acid (CA), monocaprylin (MC, monoglyceride ester of CA) and sodium caprylate (SC) on Edwardsiella ictaluri, E. tarda, Streptococcus iniae and Yersinia ruckeri in Mueller Hinton broth (MHB) were investigated. In addition, the bactericidal kinetics of CA and MC on the aforementioned pathogens in MHB, and that of SC in water, were determined. The MIC of CA and SC on E. ictaluri, E. tarda, S. iniae and Y. ruckeri were 7.5 and 50 mM, 7.5 and 50 mM, 10 and 25 mM, and 7.5 and 25 mM respectively. For MC, the MIC was in between 2.5 and 5 mM for all the pathogens. The MBC of CA, MC and SC on E. ictaluri, E. tarda, S. iniae and Y. ruckeri were 10, 5 and 100 mM; 10, 5 and 100 mM; 15, 5 and 75 mM; and 10, 5 and 75 mM respectively. The three lipid molecules exerted a substantial antimicrobial effect on the fish pathogens studied. The results indicate that CA and its derivatives could potentially be used for treating and controlling bacterial fish diseases, but extensive validation studies in fish are needed before recommending their usage.     

Gross signs and histopathology of branchiostegal blister disease (balloon disease): an idiopathic disease of farmed Macrobrachium rosenbergii (De Man)

The giant freshwater prawn, Macrobrachium rosenbergii, is facing increased threat due to disease as its culture becomes more widespread. A disease characterized by the swelling of the branchiostegal region and deformities of the appendages, named balloon disease by farmers, has caused considerable economic loss in the Nellore region of Andhra Pradesh, India. Clinical signs of diseased animals include a voluminous hypertrophy of some gill filaments and the inner area of the branchiostegite. By histology, hypertrophied areas at the level of the gill filaments or branchiostegite had an identical structure corresponding to a large cyst filled with a fluid containing a few free haemocytes, limited on one side by the cuticle and on the other by the subcuticular epithelial layer. Analysis of the diseased prawns did not reveal any pathogenic agent leading us to conclude that the disease is idiopathic, probably due to suboptimal water quality conditions.     

Genetic variability and heritability estimates for hardseededness and flowering in balansa clover (Trifolium michelianum Savi) populations

Suitability of annual pasture legume species like balansa clover (Trifolium michelianum Savi) in southern Australian farming systems depends on their hardseededness and time to flowering. Late maturing varieties with increased rate of hardseed breakdown, particularly in the late summer—early autumn period are desirable to ensure reliable regeneration in permanent pastures. Two half-sib family balansa clover populations were used to estimate heritability for the rate of breakdown of hardseededness and time to flowering. High narrow-sense heritability estimates (90.5–96.1%, rate of hardseed breakdown; 85.9–94.5%, time to flowering) were obtained, and were mainly attributed to additive gene effects. There was no relationship between rate of hardseed breakdown and time to flowering in Group1 half-sib family, which indicated that selection for both traits could be undertaken independently. In half-sib family Group 2 the relationship between the two traits suggested the possibility of selecting late maturing cultivars with increased rate of hardseed breakdown. Significant differences in time to flowering and rate of hardseed breakdown both within and between the two half-sib family groups suggested that phenotypic recurrent selection would be effective in improving the traits in these populations.     

Floral biology and artificial pollination in Dioscorea alata L.

Summary Floral biology of Dioscorea alata L. was studied. Anthesis occurred in male flowers by 12.30 h and in female flowers between 13.00 h and 14.30 h. Male flowers remained open for 4–5 hours and female flowers for 9–11 days.Natural pollination was practically absent but parthenocarpic fruit development was observed in rare cases. For hand pollination a simple and efficient pencil method was standardised. Pollen remained viable for 4–5 hours whereas stigma receptivity lasted for 9–10 days. The optimum time of pollination was found to be between 12.00 h and 15.00 h. Several factors like high relative humidity, atmospheric temperatures below 30°C and non-bagging the female flowers were found to promote fruit set.     

Ammonia Metabolism in the Leaves and Ears of Wheat (Triticum aestivum L.) During Growth and Development

The pattern of free NH₄⁺ accumulation and its metabolism was studied during the growth and development of field-grown wheat cv. HD 2204 at two applied N levels viz. 30 and 120 kg ha⁻¹. The study was confined to the 3rd, 5th and flag leaf blades and the developing ears, borne on the main shoot, during their ontogeny. The NH₄⁺ levels were considerably lower in young leaves and increased sharply as the leaves senesced when the activity of glutamine synthetase (GS) declined. In contrast to GS, glutamate dehydrogenase (GDH) remained active even during senescence. Concentrations of protein, free amino acid and total reduced N declined with age in the leaves. An assessment of free NH₄⁺ pool, free amino acid content and the activity of GS and GDH in the floral parts revealed that glumes, awns and grains also were active sites of NH₄⁺ turnover. Higher applied N level not only increased leaf and grain N concentration but also led to higher free NH₄⁺ levels in leaves and in developing ears. Presence of NH₄⁺ in the entrapped transpirate revealed that NH₄⁺ is released from both leaves and ears during senescence.