Participation of ascorbic acid in the dormancy establishment of poplar lateral branch buds

This work studied the participation of ascorbic acid (AA) in the dormancy establishment of apical buds of poplar (Populus deltoides Bartram ex Marshall cv. Catfish 2) lateral branches. AA content was highest during the active growth period and decreased to the lowest content during bud dormancy. The accumulation of the oxidised form, dehydroascorbate, was similar in either growth or dormant bud stages. The supplementation of buds with AA at the end of the summer delayed bud set. Similarly, the supplementation of buds with gibberellic acid extended the growth period and kept a high AA content in the apoplast. These results suggest that a decrease in the accumulation of reduced AA might be needed for the dormancy establishment in apical buds of poplar lateral branches.     

Effects of progestagen exposure duration on estrus synchronization and conception rates of crossbreed ewes undergoing fixed time artificial insemination

Synchronization of estrus and ovulation are of paramount importance in modern livestock improvement programs. These methods are critical for assisted reproduction technologies, including artificial insemination and embryo transfer, that can increase productivity. In the current study, subcutaneous implants containing norgestomet were placed for long (14 days), medium (9 days), and short (5 days) periods of time in 70 crossbred ewes undergoing fixed-time artificial insemination. The resulting effects on estrus synchronization and conception rates were subsequently evaluated. Among the synchronized ewes, 85.7% (60/70) underwent estrus over a period of 72 h after progestagen treatment ceased. The shortest mean interval between withdrawal of the device and onset of estrus (34.2 ± 8.9 h) was observed in the G14 days of P4 group (p < 0.05). The conception rate of the G14 days of P4 group was statistically higher than that of the other groups (83.3% vs. 60.9% vs. 47.8%; p < 0.05). In conclusion, 14 days of norgestomet treatment produced higher conception rates and a greater number of pregnancies at the beginning of the breeding season.     

Pseudodelphis limnicola sp. n. (Dracunculoidea: Guyanemidae) from the heart of Percichthys trucha (Perciformes: Percichthyidae) in Patagonian Andean Lakes (Argentina)

During a survey of parasites of Percichthys trucha (Cuvier et Valenciennes) (Perciformes: Percichthyidae) in northwestern Patagonian lakes, a new dracunculoid of the family Guyanemidae was found parasitizing as adults the heart of the fish. This species belongs to the genus Pseudodelphis Adamson et Roth, 1990 by having deirids, glandular multinucleate oesophagus and anterior branch of the uterus, and by lacking caudal alae and a gubernaculum. Pseudodelphis limnicola sp. n. differs from Pseudodelphis oligocotti Adamson et Roth, 1990 by the number and distribution of the cephalic papillae, a muscular oesophagus submerged into the glandular portion and by lacking a peribuccal ring. This is the first record of a guyanemid inhabiting the heart of a Neotropical perciform fish.     

Glyphosate- and imazethapyr-induced effects on yield, nodule mass and biological nitrogen fixation in field-grown glyphosate-resistant soybean

Over half of the 21 Mha of soybean planted in Brazil is now transgenic glyphosate-resistant (GM_RR). A field experiment was carried out to investigate whether the application of glyphosate or imazethapyr to the GM_RR variety reduced the input of N₂ fixation (BNF). No effects on yield, total N accumulation, nodulation and BNF (δ¹⁵N) could be assigned to the genetic modification of the plant. Imazethapyr reduced soybean yield but had no significant effect on BNF. Even though yields were not affected by glyphosate, the significant reduction of nodule mass and BNF to the GM_RR suggests that the use of this herbicide could lead to an increased dependence on soil N and consequently an eventual decrease of SOM reserves.     

Efficacy of formic acid in gel for Varroa control in Apis mellifera L.: importance of the dispenser position inside the hive

The efficacy of formic acid in a gel matrix was evaluated in two groups of honeybee colonies. In Group 1, a dispenser with 120 g of formic acid (70%) in gel was placed on the brood combs and another dispenser with the same dose was located on the hive bottom (total dose, 240 g). Group 2 received two doses of 240 g of formic acid (70%) in gel and each application was applied in two dispensers containing 120 g of the formic acid solution each and they were located over the brood chamber (total dose, 480 g). In Group 2, the period between both applications was 15 days, and the efficacies after the first and both applications were calculated. Significant differences were registered for final efficacy between both groups. When final efficacy of Group 1 was compared with efficacy after first application of Group 2, significant differences were found (P=0.0005). Same doses in different positions within the hive have different final efficacy. The higher efficacy was registered when the dispensers were placed over brood combs and on the hive bottom. It is suggested that efficacy is related to dispenser position within the hive.     

Science and conservation of Amazonian crocodilians: a historical review

1. Crocodilians represent one of the oldest extant vertebrate lineages. They have co-existed with humans throughout the Amazon basin for thousands of years, often having a strong cultural and economic influence on people's lives. Shifts in the socio-economic and political reality of the Amazon basin during the last century have led crocodilian populations to face large variations in their numbers according to different levels of exploitation and strategies for their conservation.
2. This article reviews the scientific knowledge obtained between 1945 and 2019 on the biology, conservation and management for the four Amazonian crocodilian (caiman) species (Caiman crocodilus, Melanosuchus niger, Paleosuchus palpebrosus and Paleosuchus trigonatus). It provides a general overview on past and current population status and research efforts involving caimans in the Amazon basin and discusses perspectives for the future.
3. The most significant studies on the ecology, genetics and management strategies are examined in more detail and this information is contextualized to provide an overview of the most relevant findings that might explain caiman population trends over the last 75 years.
4. Systems for sustainable management in the Amazon basin have been discussed for the past 20 years, but remain rarely applicable. It is necessary to develop new ways to maintain healthy caiman populations through innovative management programmes. Sustainable harvesting of wildlife has been shown to promote conservation targets, especially those initiatives based on community co-management. In this article, we propose some general guidelines for future management schemes, in the expectation that the information provided by the scientific community will be considered fully without political agendas determining the priorities.

     

Evaluation of Magnetic Coagulant (α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-MO) and its Reuse in Textile Wastewater Treatment

The textile industries are characterized as one of the biggest consumers of potable water and chemical products throughout its process, being responsible for the elevated wastewater generation with intense coloration and wide polluting potential. In this context, the present study proposes the development and application of a new coagulant material for textile wastewater treatment. The proposed coagulant (α-Fe₂O₃-MO) was composed by hematite nanoparticles (α-Fe₂O₃) obtained by a simple non-pollutant methodology, associated with Moringa oleifera (MO) seeds saline extract compounds. Coagulation/flocculation (CF) efficiency was evaluated by removal of physicochemical parameters such as apparent color, turbidity, and compounds with absorption at UV_254nm (UV_254nm) through CF tests carried out on Jar test equipment and sedimentation carried out in the presence and absence of external magnetic field (600 k Am^?1). Kinetics sedimentation was from 0 to 90 min. The use of this new coagulant allowed the removal of 92.37% for apparent color, 91.43% for turbidity, and 46.09% for UV_254nm, indicating that the proposed coagulant association was efficient in the treatment of this type of wastewater under external magnetic field with only 10 min of sedimentation. In addition, the resulting sludge from CF process was tested as base material for a new coagulant synthesis, demonstrating great reuse potential. Therefore, the new proposed coagulant, composed of α-Fe₂O₃ and the compounds present in the seed extract of MO, has applicability for textile wastewater treatment demonstrating high removal rate for all evaluated parameters with cost reduction in the proposed treatment for this wastewater.     

Factors affecting in vitro adventitious shoot formation on internode explants of Citrus aurantium L. cv. Brazilian

The in vitro formation of newly formed adventitious buds and shoots from internodal branch segments was studied on 12-month-old plants of Citrus aurantium L. cv. Brazilian. The effects of 6-Benzyladenine (BA) and α-Naphthalene acetic acid (NAA) treatments were evaluated on adventitious bud and shoot regeneration. High rates of bud initiation and shoot development were obtained both with BA supplemented medium, in the range from 1 mg L⁻¹ to 3 mg L⁻¹, and with 0.1 mg L⁻¹ NAA supplemented medium. NAA concentrations above 1 mg L⁻¹ significantly reduced bud initiation and shoot elongation. The results obtained using different in vitro culture vessels such as Petri dishes, tubes and glass culture jars were compared. The highest adventitious bud induction was observed in Petri dishes for internodes cultured in 2 mg L⁻¹ BA supplemented medium, with 95% responsive explants forming 9.0 ± 2.4 adventitious buds. The adventitious buds observed in Petri dishes reached a maximum height of 1 mm, with no further development, while some of the adventitious shoots cultured in tubes and glass culture jars grew over 1 cm in height. A shoot regeneration gradient of the internodes collected along the branch axis was noticed, with basal ones exhibiting higher regeneration frequency.     

A field evaluation of anthelmintics for control of cyathostomes of horses in Brazil

The anthelmintic efficacy of ivermectin (IVM), piperazine citrate (PPZ) and fenbendazole (FBZ) alone, and combinations of FBZ with varying dosages of PPZ, was evaluated for the control of strongyles of Mangalarga equids. In all cases of positive strongly egg counts per gram of faeces (EPG) before and after treatment, pure populations of cyathostome larvae with eight gut cells were consistently observed in faecal cultures. The faecal egg count reductions (FECR) were evaluated between Day 7 and Day 56 post-treatment. Significant differences (P less than or equal to 0.05) were found between Day 7 and Day 49 when comparing the mean EPG values of IVM with those of the other anthelmintics. PPZ alone and the combination of FBZ (7.5 mg kg-1) and PPZ (55 mg base kg-1) did not show significant differences during the trial; both groups exhibiting an FECR of greater than 90% between Day 7 and Day 30. Horses treated with the combinations of FBZ (7.5 mg kg-1) and PPZ at either 40 or 25 mg base kg-1, and with FBZ alone at either 7.5 or 15 mg kg-1, showed an FECR of less than 90% 2 weeks after treatment. The emergence of a degree of resistance of strongyles to FBZ and PPZ in a segment of the cyathostomes in this population is suggested.     

Adjuvant effect of green propolis on humoral immune response of bovines immunized with bovine herpesvirus type 5

Despite recent technological advances in vaccine production, most vaccines depend on the association with adjuvant substances. In this study, propolis, which has been attracting the attention of researchers due to its bioactive properties, was evaluated as an immunological adjuvant. The association of 40mg/dose of an ethanolic extract of green propolis with an inactivated oil vaccine against bovine herpesvirus type 5 (BoHV-5), resulted in a significant increase (P<0.01) in the neutralizing antibody levels, comparing to the bovines that received the same vaccine without propolis. Besides, propolis increased the percentage of animals with high antibody titers (above 32). Phenolic compounds such as artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) and the derivatives of cinnamic acid besides other flavonoid substances were abundant in the propolis extract used, and they could be the main substances with adjuvant action. The effect of the green propolis extract on the humoral immune response can be exploited in the development of new vaccines.