In Situ Batch Denitrification of Nitrate-Rich Groundwater Using Sawdust as a Carbon Source—Marydale, South Africa

Batch experiments were performed to denitrify groundwater using sawdust as a carbon source at Marydale, South Africa. Alkalinity, pH, electrical conductivity, nitrate, nitrite, ammonia, SO ₄ ^2? , heterotrophic plate count (HPC), dissolved organic carbon (DOC), potassium and chloride were monitored. Two soil depths, 75 to 100 and 165 to 200 cm, respectively, from the Marydale area were used as matrix material during denitrification based on contrasting chemical composition with respect to major ion composition and moisture to consider different denitrification rates for varying soil depths. Different N to C ratios were used to evaluate the denitrification efficiency and the least undesirable products, e.g., elevated SO ₄ ^2? , H₂S and other reduced compounds. DOC is directly proportional to the N to C ratio used. Nitrite was produced for most of the treatments as incomplete denitrification occurred. The incubation periods were 28 and 43 days, respectively. N to C ratios were 12.6:1, 24:1, 34:1 and 54:1. Longer incubation period and higher N to C ratio resulted in total removal of both nitrate and nitrite. The reaction was carbon-limited for lower N to C ratios. The denitrification rate was proportional to the carbon availability at any time during the experiment. There was no significant difference in denitrification using heterogeneous and homogeneous particle sizes for sawdust. Soil depth of 75–100 cm displayed a greater denitrification rate than 165–200-cm soil depth due to higher initial soil nitrate concentration. The method showed some specificity, as DOC, nitrite, nitrate, alkalinity and HPC were the only parameters that showed a change in concentration over the duration of the denitrification experiment under constant temperature and nitrogen gas atmosphere. DOC and HPC were unacceptable for domestic use, but methods such as boiling or chlorinating water can rid it of bacteria.     

Identification of a new genotype of canine distemper virus circulating in America

Canine Distemper is a highly contagious viral systemic disease that affects a wide variety of terrestrial carnivores. Canine Distemper virus (CDV) appears genetically heterogeneous, markedly in the hemagglutinin protein (H), showing geographic patterns of diversification that are useful to monitor CDV molecular epidemiology. In Mexico the activity of canine distemper remains high in dogs, likely because vaccine prophylaxis coverage in canine population is under the levels required to control effectively the disease. By phylogenetic analysis based on the nucleoprotein (N) and on the H genes, Mexican CDV strains collected between 2007 and 2010 were distinguished into several genovariants, all which constituted a unique group, clearly distinct from field and vaccine strains circulating worldwide, but resembling a CDV strain, 19876, identified in Missouri, USA, 2004, that was genetically unrelated to other North-American CDV strains. Gathering information on the genetic heterogeneity of CDV on a global scale appears pivotal in order to investigate the origin and modalities of introduction of unusual/novel CDV strains, as well as to understand if vaccine breakthroughs or disease epidemics may be somewhat related to genetic/antigenic or biological differences between field and vaccine strains.     

Proteomic analysis of digestive tract peptidases and lipases from the invasive gastropod Pomacea canaliculata

Background

The invasive gastropod Pomacea canaliculata has received great attention in the last decades as a result of its negative impact on crops agriculture, yet knowledge of their digestive physiology remains incomplete, particularly the enzymatic breakdown of macromolecules such as proteins and lipids.

Results

Discovery proteomics revealed aspartic peptidases, cysteine peptidases, serine peptidases, metallopeptidases and threonine peptidases, as well as acid and neutral lipases and phospholipases along the digestive tract of P. canaliculata. Peptides specific to peptidases (139) and lipases (14) were quantified by targeted mass spectrometry. Digestion begins in the mouth via diverse salivary peptidases (nine serine peptidases; seven cysteine peptidases, one aspartic peptidase and 22 metallopeptidases) and then continues in the oesophagus (crop) via three luminal metallopeptidases (Family M12) and six serine peptidases (Family S1). Downstream, the digestive gland provides a battery of enzymes composed of aspartic peptidase (one), cysteine peptidases (nine), serine peptidases (12) and metallopeptidases (24), including aminopeptidases, carboxypeptidases and dipeptidases). The coiled gut has M1 metallopeptidases that complete the digestion of small peptides. Lipid extracellular digestion is completed by triglyceride lipases.

Conclusion

From an integrative physiological and anatomical perspective, P. canaliculata shows an unexpected abundance and diversity of peptidases, which participate mainly in extracellular digestion. Moreover, the previously unknown occurrence of luminal lipases from the digestive gland is reported for the first time. Salivary and digestive glands were the main tissues involved in the synthesis and secretion of these enzymes, but plausibly the few luminally exclusive peptidases are secreted by ventrolateral pouches or epithelial unicellular glands. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Mycoflora and occurrence of alternariol and alternariol monomethyl ether in Brazilian sunflower from sowing to harvest

The present study aimed to analyze the mycoflora and the occurrence of alternariol (AOH) and alternariol monomethyl ether (AME) in grain samples of sunflower during different stages of plant development in Nova Odessa, State of S?o Paulo, Brazil. The data obtained were correlated with the presence of fungi in soil, wind-dispersed fungi, and the predominant climatic conditions of the region where the experiment was carried out. Analysis of the mycoflora revealed the presence of Fusarium verticillioides and Alternaria alternata in 70% and 46% of the samples, respectively. The profile of wind-dispersed fungi also showed F. verticillioides as the most frequently isolated fungus (68%), although A. alternata was detected in 28% of samples. In soil, Penicillium was the most frequent species (49.9%), followed by F. verticillioides (47.7%) and A. alternata (10.9%). Regarding water activity, sunflower grains presenting a high frequency of isolation of F. verticillioides and A. alternatahad a water activity ranging from 0.92 to 0.96, and statistical analysis revealed a negative linear correlation between the isolation of fungi and water activity. HPLC analysis showed that 18% of the sunflower grains were contaminated with alternariol (24.9-170.9 ng/g) and 10% with alternariol monomethyl ether (14.1-108.6 ng/g). The contamination of sunflower grains with AOH and AME in the field was low when compared to the LD50 necessary to cause toxicity to animals. However, the contamination with other toxigenic fungi such as F. verticillioides may indicate the presence of other mycotoxins in sunflower grains and a possible synergistic effect between them. This is the first report of the natural occurrence of alternariol and alternariol monomethyl ether in sunflower grains in Brazil.     

Performance of ‘Coscia’ pear (Pyrus communis) on nine rootstocks in the north of Israel

The vegetative and reproductive performances of ‘Coscia’ pear (Pyrus communis L.) grown on nine rootstocks [OHF 69, OHF 97, OHF 217, OHF 333, OHF 513 and BP 1 (P. communis), clonal seedling (Davis AxB) of Pyrus betulifolia and quince BA 29 and EMA (Cydonia oblonga)] were compared during a 9-year period. The trial was conducted at the Experimental Station ‘Avnei Eitan’ in northern Israel (elevation 400 m above sea level, a.s.l.), on a well-drained soil with pH 7.1. Trees were planted in December 1998, spaced at 4.0 m × 2.0 m and trained with a central axis. The most vigorous trees were on P. betulifolia seedlings, followed by the four OHF rootstock (69, 97, 333, 513) and BP 1 (with no significant difference between them). All the above rootstocks demonstrated greater vigor than OHF 217 and quince BA 29 or EMA. The highest cumulative yields per tree were harvested from trees on the four OHF rootstocks (69, 97, 333, 513) and P. betulifolia followed by the BP 1. The two quince rootstocks, as well as OHF 217, had the lowest cumulative yield and the lowest yield of large fruit. A positive correlation was found between the vigor of the tree, as affected by the rootstock, and both the total yield and the fruit size. We conclude that in a warm climate, yield efficiency is not the only parameter that should be taken into account, and building a strong tree for a weak cultivar is the first requirement for establishing an orchard.     

Problems of potato breeding in Israel

Potato Research - In the spring of 1957 a breeding programme was begun for the purpose of creating a potato variety with a short dormancy and a short to medium growing period. Since there are two...     

Genetic progress during 22 years of black bean improvement

The common bean breeding program coordinated by Embrapa Arroz e Feijão released 50 new cultivars from 1984 to 2010. The aim of the present study was to estimate genetic progress in terms of seed yield and other agronomic traits achieved by the black-type common bean breeding program in Brazil over the 22-year period from 1985 to 2006. Two types of field experiments were performed to assess genetic progress. In regard to experiments on lines, the three best breeding lines from each of 11 evaluation cycles constituted 33 treatments. These evaluations were made in 20 environments and served to estimate progress in seed yield and seed size because these were the criteria applied in selecting the elite lines. Cultivar evaluations included nine cultivars recommended by Embrapa during the period under investigation, and the evaluations were established in 21 environments. These evaluations served to estimate improvements in reaction to angular leaf spot, plant architecture and tolerance to lodging because cultivars usually exhibit superior phenotypes for such characteristics. Evaluations were performed from 2008 to 2010. Estimated improvement in seed yield was 25.2 kg ha^?1 or 1.1 % per year. Improvements were also found in tolerance to lodging (1.7 % per year) and 100-seed weight (0.65 % per year). There was no significant progress for the plant architecture and resistance to angular leaf spot traits.     

Effect of elevated CO2 on vegetative and reproductive growth characteristics of the CAM plants Hylocereus undatus and Selenicereus megalanthus

This study examined the vegetative and reproductive growth responses of the crassulacean acid metabolism (CAM) vine-cactus fruit crop species Hylocereus undatus and Selenicereus megalanthus to CO₂ enrichment (1000 μmol mol⁻¹ vs. control of 380 μmol mol⁻¹). H. undatus plants enriched with CO₂ demonstrated 52%, 22%, 18%, and 175% increases, relative to plants measured in ambient CO₂, in total daily net CO₂ uptake, shoot elongation, shoot dry mass, and number of reproductive buds, respectively. The responses of S. megalanthus plants exposed to elevated CO₂ were greater than those of H. undatus under the same conditions. Compared to plant responses in ambient CO₂, under conditions of CO₂ enrichment, S. megalanthus showed 129%, 73%, 68%, and 233% increases in total daily net CO₂ uptake, shoot elongation, shoot dry mass, and number of reproductive buds, respectively. Moreover, for H. undatus, there was no significant change in fruit fresh mass although it showed a slight (7%) upward trend. On the other hand, fruit fresh mass of S. megalanthus significantly increased by 63% in response to elevated CO₂. These results indicate the high potential of CAM plants to respond to CO₂ enrichment. It is thus apparent that S. megalanthus grown under CO₂ enrichment may benefit from elevated CO₂ to a greater extent than H. undatus grown under sub-optimal growth conditions.     

From landraces to modern cultivars: field observations on taro <Emphasis Type="Italic">Colocasia esculenta</Emphasis> (L.) Schott in sub-Saharan Africa

Until recently, taro Colocasia esculenta (L.) Schott, was considered a neglected food crop due to its low palatability and inferior value compared to other root crops such as cassava, potatoes and yams. Under the impulse of new studies on plant dispersal, and in light of the severe threats posed by pests to its conservation status, this crop has finally received more attention. However, there is still insufficient knowledge on specific cultivars and their culinary and medicinal uses, especially in Africa. We studied the agrodiversity of taro cultivars in Nigeria, Cameroon, the Democratic Republic of Congo, Kenya, and Tanzania. Here, we present ethnobotanical, morphological and linguistic data of 20 taro cultivars, as well as specific notes on abandoned landraces. These traditional varieties represent valuable genetic resources and can be instrumental in protecting taro from the genetic erosion caused by preference for yautia, and diseases such as the leaf blight. With this work, we call for renewed efforts to conserve this species and its landraces.