Adult Body Length Research Articles

Phenotypic and Carcass Characterization of Hassan Sheep

Background: Hassan sheep is the third most populous breed of the five registered sheep breeds from Karnataka with limited studies on its morphological and carcass characteristics. Hence, the study was undertaken to know the present status of morphological and carcass characteristics of this breed. Methods: A total of 34 randomly selected flocks were surveyed and the data on various parameters were collected. The morphometrical data was collected on 344 sheep belonging to eight flocks from the breeding tract. The carcass characteristics were documented by slaughtering six male lambs (between nine to twelve months of age). Result: These sheep had varied coat colours viz. complete white (23.3%), white with light brown patches (58.1%) and white with black patches (18.6%) on head and neck region. It was observed that 40.4 per cent of males and only 1.4 per cent of females were horned. Atrophied ears were noticed in 2.3 per cent of these sheep. The average adult body length (cm), height at wither (cm), chest girth (cm), paunch (cm), ear length (cm), tail length (cm) and average adult body weight (kg) were 66.4±0.62, 65.03±1.45, 75.2±1.02, 76.5±1.38, 15.2±0.07, 11.5±0.07 and 32.7±2.03 in males and 63.8±0.85, 61.7±1.38, 71.8±2.32, 74.5±2.60, 15.0±0.34, 11.3±0.08 and 27.8±1.21 in females, respectively. The difference in body weight between males and females increased significantly over the age. The pre-slaughter weight (PSW), hot carcass weight (HCW) and dressing percentage recorded were 20.3±1.42 Kg, 9.5±0.23 kg and 46.80 per cent, respectively.

Histone deacetylase HDA-4-mediated epigenetic regulation in space-flown C. elegans

Epigenetic changes during long-term spaceflight are beginning to be studied by NASA’s twin astronauts and other model organisms. Here, we evaluate the epigenetic regulation of gene expression in space-flown C. elegans by comparing wild type and histone deacetylase (hda)-4 mutants. Expression levels of 39 genes were consistently upregulated in all four generations of adult hda-4 mutants grown under microgravity compared with artificial Earth-like gravity (1G). In contrast, in the wild type, microgravity-induced upregulation of these genes occurred a little. Among these genes, 11 contain the domain of unknown function 19 (DUF-19) and are located in a cluster on chromosome V. When compared with the 1G condition, histone H3 trimethylation at lysine 27 (H3K27me3) increased under microgravity in the DUF-19 containing genes T20D4.12 to 4.10 locus in wild-type adults. On the other hand, this increase was also observed in the hda-4 mutant, but the level was significantly reduced. The body length of wild-type adults decreased slightly but significantly when grown under microgravity. This decrease was even more pronounced with the hda-4 mutant. In ground-based experiments, one of the T20D4.11 overexpressing strains significantly reduced body length and also caused larval growth retardation and arrest. These results indicate that under microgravity, C. elegans activates histone deacetylase HDA-4 to suppress overregulation of several genes, including the DUF-19 family. In other words, the expression of certain genes, including negative regulators of growth and development, is epigenetically fine-tuned to adapt to the space microgravity.

EVALUATING COMPOSITIONAL FIDELITY AND SOURCES OF MORTALITY OF SHORELINE FISH CARCASSES IN A FRESHWATER LAKE COMMUNITY IN WESTERN CANADA

ABSTRACT Taxonomic comparisons of death assemblages with extant communities continue to provide insight for ecological studies but whether demographic aspects such as age structure, sex ratio, and causes of mortality are accurately captured by the former remains little studied. At a 110 ha dystropic lake in western Canada, seasonal shoreline accumulations of fish carcasses were collected annually for 12 years (N=4499) during 95 full lake-circuits and analyzed for taxa, body size frequencies, sex ratio relative to live-captures and sources of mortality. Rank order of the four fish species (Gasterosteus aculeatus, Oncorhynchus clarki, O. keta, Salvelinus malma) was similar for live-captures and carcasses. Of the dominant species (G. aculeatus), modal adult body length (∼80 mm SL) was the same for carcasses and live-captures and shifted by about 10% over 30 years with parallel trends between the groups for both sexes. Age-specific body size was about 5% larger (P<0.001) in carcasses than live-captures. Carcasses were significantly female-biased (2:1) each year relative to a population sex ratio of 1:1 in the lake. There was a complete absence of juvenile fish (<30 mm) among carcasses but these constituted 70% of the live population. Estimated relative contributions to mortality for the carcasses include starvation (<1%), parasitism (3%), senescence (4%) and lethal injuries from predator attack (70–80%). If these carcasses are representative of a fossil series in freshwater lake sediments, then several demographic parameters including age-specific body size, age-class frequencies and sex ratio depart substantially from the live population. As well, the virtual absence of avian piscivores in the carcass assemblage, the major source of predation on the fish population, warrants additional attention in paleoecological studies.

Making Sense of Life-History Effects of the Antidepressant Citalopram in the Copepod Nitocra spinipes Using a Bioenergetics Model.

The global consumption of human antidepressants has steadily increased over the last years. The most widely prescribed antidepressants are the selective serotonin reuptake inhibitors (SSRIs), which have been linked to various life-history effects in nontarget organisms. We investigated the effects of the SSRI citalopram hydrobromide on the life history of the copepod Nitocra spinipes. Slight but significant developmental delay effects were observed at nominal concentrations of 0.1 and 1 µg/L, with stronger effects occurring at measured concentrations of 178 µg/L and above. At 77 µg/L and above, a significant increase in adult body length and offspring production/brood was found, although the time between brood releases remained unaffected. The pre-adult surviving fraction was significantly reduced (by 44%) at 765 µg/L. For a mechanistic evaluation of these observations, we used a bioenergetics model for N. spinipes based on the dynamic energy budget theory. Toxicokinetic and toxicodynamic submodels were used to dynamically simulate the chemical uptake and elimination, as well as dose-response relationships for hypothetical physiological modes of action and survival over time. Although none of the commonly invoked physiological modes of action, acting on assimilation, maintenance, growth, or offspring production, could explain the observed combination of effects, a newly proposed physiological mode of action acting on the process of maturation delivered correct predictions in terms of each effect's direction. The model fits could be further improved by allowing for a gentler concentration-effect slope and by adding an auxiliary physiological mode of action acting on the reproduction efficiency. The quantitative explanations provided in the present study offer a starting point for exploratory simulation studies investigating the effects of SSRIs at higher ecological levels. Environ Toxicol Chem 2021;40:1928-1939. © 2021 SETAC.

Etelis boweni sp. nov., a new cryptic deepwater eteline snapper from the Indo-Pacific (Perciformes: Lutjanidae).

A new species of Etelis is described based on 16 specimens collected from the Red Sea and Western Australia, with confirmed genetic records throughout the Indo-West Pacific. It is similar to and was often misidentified as Etelis carbunculus Cuvier, with both species sharing the diagnostic character of low number of developed gill rakers. Nonetheless, the two species are genetically divergent and differ morphologically in adult body length; proportions of eye, snout, cheek and caudal fin; shape of head, opercular spine and sagittal otolith; and coloration of the tip of the upper caudal fin. Etelis boweni has a wide Indo-west Pacific distribution that largely overlaps with E. carbunculus, and the two species are often caught on the same fishing line.

Toxicity of lead pollution to the collembolan Folsomia candida in Ferri-Udic Cambosols

Toxic effect of lead (Pb) pollution on Collembola in soils has seldom been studied in depth, which is especially true for growth responses since the juveniles are very small and numerous. A single species test was conducted using the collembolan Folsomia candida as the indicator species, and soil Pb pollution (at Pb concentrations of 0, 300, 600, 1 200, 2 400, and 4 800 mg kg–1) was simulated by mixing Pb(NO3)2 with a natural unpolluted soil. Adult survival, reproduction, body length, and body Pb concentration were determined. Adult survival and reproduction started to decrease at soil Pb concentrations of 1 200 and 600 mg kg–1, respectively. Lead concentrations in adult and juvenile bodies increased with increasing Pb concentration in soil. The percentage and individual abundances based on body length analysis showed that the larger adults (2.1–2.6 mm, P < 0.01) were more sensitive to soil Pb concentration than the intermediate (1.9–2.1 mm, P < 0.001) and smaller (1.7–1.9 mm, P < 0.001) adults. Similarly, the larger juveniles (1.0–1.4 mm, P < 0.001) were more sensitive to soil Pb concentration than the intermediate (0.6–1.0 mm, P < 0.001) and smaller (0.3–0.6 mm, P < 0.001) juveniles. For both adults or juveniles, the abundance and percentage of larger individuals declined significantly with increasing soil Pb concentration, suggesting that larger individuals were more sensitive to soil Pb pollution. Therefore, body length features, especially the percentage and abundance of larger individuals, would be potential bio-indicators of soil Pb pollution and possibly other types of soil pollution.

Incubation in Wastewater Reduces the Multigenerational Effects of Microplastics in Daphnia magna.

The aging of microplastics in the environment changes their physicochemical properties. While this may affect their toxicity, comparative data on the effects of aged compared to pristine microplastics are scarce. One of those aging processes is the sorption of chemicals, which has mainly been studied for individual pollutants present in marine ecosystems. To investigate how the sorption of a complex mixture of freshwater pollutants affects the toxicity of microplastics, we incubated irregular polystyrene particles (≤63 μm) in either wastewater or ultrapure water. We exposed Daphnia magna to these aged microplastics and their pristine counterparts (80, 400, 2000, and 10,000 particles mL–1) over four generations using food limitation as an additional, environmentally realistic stressor. Both particle types affect the survival, reproduction, adult and neonate body lengths, and growth. An exposure to pristine microplastics results in the extinction of the third generation of daphnids. In contrast, wastewater-incubated particles induced a lower mortality. The incubation with wastewater does not change the microplastics’ size, surface charge, and structure. Consistent with the literature, we assume that the adsorption of dissolved organic matter is a key aging process reducing the toxicity of microplastics. Consequently, toxicity testing using pristine microplastics may overestimate the effects of plastic particles in nature.

The first record of a Longman\u2019s beaked whale (Indopacetus pacificus) newborn neonate found on Miyako Island, Okinawa, Japan

The Longman’s beaked whale (Indopacetus pacificus) is one of the rarest cetaceans worldwide. Since it was first described as its own species in 1926, they have been observed alive at sea on several occasions, and less than 20 strandings have been reported worldwide to date. Thus, basic information regarding this species, such as the maximum size of adult individuals or body length at birth, remains unknown. In this study, the external appearance and DNA analysis of a female Longman’s beaked whale stranded on Miyako Island, Okinawa, Japan, are reported. The external appearance of the specimen matched the features of the Longman’s beaked whale presented in previous studies. The mitochondrial DNA control-region sequences obtained from the specimen also matched the reference sequences of the species deposited in GenBank. Based on these features, the specimen was confirmed as a Longman’s beaked whale. The specimen was estimated to be neonate because of its body length (235 cm) and the clear several fetal folds observed on its body surface. To the best of our knowledge, this is the first report of a confirmed new born neonate of Longman’s beaked whale in the world.

Морфометрические показатели ювенильной динамики Molipteryx fuliginosa (Uhler) (Heteroptera, Coreidae) на юге Дальнего Востока России

The paper provides original data on the duration of each instar period, growth dynamics, and morphometric characteristics of the preimaginal development up to the adult stage in Molipteryx fuliginosa (Uhler, 1860). The data were obtained by observations under natural and close-to-natural conditions in the South of the Russian Far East. Nymphal instars in M. fuliginosa have the following duration (days): 5–7 (m = 6.0 ± 0.87) (instar I); 13–16 (m = 14.5 ± 1.19) (II); 7–8 (m = m=7.5 ± 0.54) (III); 11–23 (m = 16.6 ± 3.93) (IV); and 19–38 (m = 27.9 ± 5.96) (V). With each molt, nymphs grow in size. The increases in body length and width are quite proportional at all the stages and account for 1.2–1.5 times. In instar II nymph, before the emergence of wing buds, these values are slightly higher: 1.5-fold and 1.4-fold in length and width respectively. The same is observed in instar V during the formation of sex differences: the body length increases 1.3-fold in ♂ and 1.5-fold in ♀. In the longest stage of development, the width of ♂ increases 1.2-fold, while the width of ♀ increases 1.4-fold. In middle-instar (III) nymph, the body growth rate is lower than in instar II. This period is marked by the development of the externally visible distinguishing traits of instar III nymphs — the tips of wing pads and the elytral buds. In older nymphs (stages IV and V), the duration of development extends again. The development of wing pads continues, and the sex differences are formed. The ratio of the body lengths of the nymphs relative to the adult body length (A, assumed to be 1) is as follows: I: II: III: IV: V: A = 0.2: 0.3: 0.4: 0.6: 0.8: 1. A comparative analysis of developmental patterns in the leaf-footed bug Molipteryx fuliginosa (Uhler, 1860) and the Far Eastern subspecies of the dock bug Coreus marginatus orientalis (Kiritshenko) (Heteroptera, Coreidae) in the South of Primorsky Territory has shown that the transition from nymph to imago lasts 40–45 days in C. m. orientalis and 55–83 days in M. fuliginosa. The average duration of instar I stage of the two species is similar. However, M. fuliginosa nymphs develop more slowly from instar II to V than C. m. orientalis nymphs by 4, 3, 11, and 13 days, respectively.

Performance of the tiger-fly Coenosia attenuata Stein reared on the alternative prey, Chironomus plumosus (L.) larvae in coir substrate

The performance of the tiger-fly Coenosia attenuata Stein was examined when fed on larvae of the buzzer midge, Chironomus plumosus (Linnaeus), and combination of buzzer midge and fungus gnat, Bradysia impatiens (Johannsen). Significant differences were observed in the developmental time of larvae, body length, and body weight of pupae and adults of C. attenuata in response to species and preservation status of prey but not in response to instar and prey number of C. plumosus. Most biological characteristics except for developmental time of pupae, length of female pupae, survival rate from the 5th day to pupation, and adult emergence improved for tiger-fly larvae fed on live B. impatiens larvae in the first four days and live C. plumosus larvae from the fifth day to pupation compared to those fed on live C. plumosus larvae in all larval stages. When live alternative prey were replaced with the frozen prey, the developmental time of larvae was prolonged, and adult male body length, survival rate from the fifth day to pupation, and the percentages of pupation and adult emergence decreased. The survival rate of larvae in the first 4 days and percentage of pupation improved with decreased alternative prey instar and increased alternative prey number. These results indicate live C. plumosus larvae can serve as an alternative food source for mass rearing of C. attenuata. As an alternative food source, C. plumosus larvae provide significant advancements for the application of tiger-fly in banker media system and/or open rearing.

Fitness and Predating Potential of Antilochus coquebertii (Hemiptera: Pyrrhocoridae): A Predator of the Red Cotton Bug (Dysdercus koenigii)

Antilochus coquebertii is one of the most important predators of Dysdercus koenigii. The present study examines for the first time the fitness (using age-stage and two-sex life table parameters), morphometrics and predating potential of A. coquebertii fed on the second instar of D. koenigii under laboratory conditions. Results indicate that female adults of A. coquebertii consumed significantly higher numbers of second instar D. koenigii (229.81 ± 14.36) when compared to male adults (118.47 ± 10.77). The body length (16.10±0.40 mm) and width (6.60 ± 0.20 mm) of female adults of A. coquebertii were significantly higher if compared to body length (14.40 ± 0.40 mm) and width (5.80 ± 0.40 mm) of male adults. The developmental period of A. coquebertii from egg to female adult (76.09 ± 3.51 days) was significantly longer than egg to male adult (64.00 ± 1.87 days). The fecundity (number of eggs/female) of A. coquebertii was 108.67 ± 3.67 per female. The intrinsic rate of increase (r) and finite rate of increase (λ) per day of A. coquebertii were recorded with values of 5.87 and 1.06 days, respectively. The gross reproductive rate (GRR) and net reproductive rate (R0) of A. coquebertii were 23.17 offspring and 18.56 offspring/individual, respectively. The information obtained in this study will be useful for the development of future research projects focused on this predator against D. koenigii under natural conditions. Based on our results, we suggest that A. coquebertii will be a good biological control agent against the second instar of D. koenigii in cotton fields.

Two new nematode species (Plectida: Leptolaimidae, Rhadinematidae) from Chatham Rise, New Zealand.

Two new species of the order Plectida are described from Chatham Rise, New Zealand. Leptolaimus dififtinus sp. nov. is characterised by the short body 319–420 microns long, truncate labial region slightly offset from body contour and bearing conspicuous outer labial papillae, cephalic setae 1.3–1.4 microns long, amphid located 4–9 microns from anterior end, lateral alae originating from middle of buccal cavity length, female without supplements, male with precloacal and postcloacal pairs of subventral setae, nine tubular supplements (alveolar supplements absent), tubular supplements weakly S-shaped with pointed tip, spicules arcuate 24 microns or 1.4 cloacal body diameters long and dorsal gubernacular apophyses. Lavareda iramscotti sp. nov. is characterised by adult body length 3,023–3,121 microns long, eight longitudinal rows of body pores each with short papilla, cephalic setae 4–5 microns long, tail 146–165 microns long, male with spicules 54 microns long, gubernaculum with triangular apophyses, 20 precloacal supplements with bifid distal tips arranged in 9 + 1 + 10 pattern, female with vulva at 55% of body length from anterior and cuticularisation perpendicular to vagina at level of vulva. The present study provides the first record of a Leptolaimus species from the New Zealand region and the first description of a female specimen of the genus Lavareda.

Mayfly emergence production and body length response to hydrology in a tropical lowland stream.

BackgroundHydrological impacts on aquatic biota have been assessed in numerous empirical studies. Aquatic insects are severely affected by population declines and consequent diversity loss. However, many uncertainties remain regarding the effects of hydrology on insect production and the consequences of energy transfer to the terrestrial ecosystem. Likewise, sublethal effects on insect morphology remain poorly quantified in highly variable environments. Here, we characterized monthly fluctuation in benthic and emerged biomass of Ephemeroptera in a tropical lowland stream. We quantified the proportion of mayfly production that emerges into the riparian forest. We also examined the potential morphological changes in Farrodes caribbianus (the most abundant mayfly in our samples) due to environmental stress.MethodsWe collected mayflies (nymphs and adults) in a first-order stream in Costa Rica. We compared benthic and adult biomass from two years’ worth of samples, collected with a core sampler (0.006 m2) and a 2 m2-emergence trap. The relationship between emergence and annual secondary production (E/P) was used to estimate the Ephemeroptera production that emerged as adults. A model selection approach was used to determine the relationship between environmental variables that were collected monthly and the emergent biomass. To determine potential departures from perfect bilateral symmetry, we evaluated the symmetry of two morphological traits (forceps and forewing) of F. caribbianus adults. We used Spearman’s rank correlation coefficients (ρ) to examine potential changes in adult body length as a possible response to environmental stress.ResultsBenthic biomass was variable, with peaks throughout the study period. However, peaks in benthic biomass did not lead to increases in mayfly emergence, which remained stable over time. Relatively constant mayfly emergence suggests that they were aseasonal in tropical lowland streams. Our E/P estimate indicated that approximately 39% and 20% (for 2002 and 2003, respectively) of the nymph production emerged as adults. Our estimated proportion of mayfly production transferred to terrestrial ecosystems was high relative to reports from temperate regions. We observed a strong negative response of F. caribbianus body length to increased hydrology (Spearman: ρ = −0.51, p < 0.001), while slight departures from perfect symmetry were observed in all traits.ConclusionOur two years study demonstrates that there was large temporal variability in mayfly biomass that was unrelated to hydrological fluctuations, but potentially related to trophic interactions (e.g., fish predation). Body length was a good indicator of environmental stress, which could have severe associated costs for mayfly fitness in ecosystems with high temporal variation. Our results highlight the complex ecological and evolutionary dynamics of tropical aquatic insects, and the intricate connection between aquatic and terrestrial ecosystems.

Association of inhibin alpha gene polymorphism with litter size and growth in Malabari goats of India

Abstract The present study was carried out to identify single nucleotide variations in inhibin alpha (INHA)geneto evaluate its association with production traits in Malabari goats. A total of 251 Malabari adult goats were screened for polymorphism using PCR-SSCP.Representative samples of each SSCP pattern were sequenced to ascertain the genotypes. Five fragments, 274 bp, 220 bp, 160 bp, 287 bp and 253 bp covering the two exons of INHA were analyzed. The 274 bp fragment showed two diplotypes (AA and AB) and sequencing revealed one synonymous SNP (c.129 G > A) in exon 1. The AA genotype showed significant (p ≤ 0.05) association with body length. Similar monomorphic band pattern was observed for 220 bp fragment of exon 2. The 160 bp fragment exhibited two genotypes DD and DE with a synonymous SNP c.567 G > A in exon 2. Goats carrying DD genotype had significantly (p ≤ 0.05) higher adult body weight and body length compared to DE genotype. Three diplotypes, HH, HJ and JJ with a synonymous SNP, c.651 G > A were observed at 287 bp fragment. Significantly (p C. Genotypes of INHA 253 bp (exon 2) locus had significant (p ≤ 0.05) influence on litter size, body weight and trunk circumference. The PP and PQ showed a significantly higher litter size and trunk circumference (p ≤ 0.05) compared to QQ genotypes.Present study indicated the potential role of INHA gene on reproduction and growth, hence it can be used as a candidate gene in the improvement of Malabari goats.

Changes in capture rates and body size among vertebrate species occupying an insular urban habitat reserve

AbstractLong‐term ecological monitoring provides valuable and objective scientific information to inform management and decision‐making. In this article, we analyze 22 years of herpetofauna monitoring data from the Point Loma Ecological Conservation Area (PLECA), an insular urban reserve near San Diego, CA. Our analysis showed that counts of individuals for one of the four most common terrestrial vertebrates declined, whereas counts for other common species increased or remained stable. Two species exhibited declines in adult body length, whereas biomass pooled over the five most common species increased over time and was associated with higher wet season precipitation. Although the habitat and vegetation at PLECA have remained protected and intact, we suspect that changes in arthropod communities may be driving changes in the abundance, growth, and development of insectivorous lizards. This study underscores the value of long‐term monitoring for establishing quantitative baselines to assess biological changes that would otherwise go undetected.

Redescription of Paratrophurus anomalus (Rhabditida: Dolichodoridae) from South Africa

Summary Paratrophurus anomalus is redescribed from the North-West Province, South Africa, associated with the rhizosphere of a willow tree, a dominant ornamental tree in the province. This population is characterised by its adult body length (696 (625-834) μm for female and 706 μm for male), lateral field with four longitudinal incisures, cephalic framework well cuticularised, lip region smooth and lacking annuli, female stylet 19.6 (18-21) μm long, female tail cylindrical, 35 (31-38) μm long, c′ = 2.3 (2.1-2.8), with thick hyaline region forming 31-43% of the tail length, spicules 22 μm long and gubernaculum 12 μm long. Morphologically, P. anomalus is very similar to P. kenanae and P. dissitus, although they differ on the basis of lip region morphology, stylet length, hyaline tail region, and spicule length. In addition, SEM observations are provided for the first time for this species along with a new host and new geographical record of the species from South Africa, providing new information for the revision of Paratrophurus. Molecular analysis of P. anomalus using ITS rDNA showed a close relationship with P. bursifer, P. bhutanensis and Bitylenchus species. In addition, principal component analysis was done for 14 character states of species in the genus.

Methionine as a methyl donor regulates caste differentiation in the European honey bee (Apis mellifera).

Nutrition contributes to honey bee caste differentiation, but the role of individual nutrients is still unclear. Most essential amino acid contents, except that of methionine (Met), are greater in royal jelly than worker jelly. After ∼3.5 d, the Met content in the latter was slightly greater than in the former. Met is the major raw material used in the synthesis of S-adenosyl-L-methionine, an active methyl donor for DNA methylation, which is an epigenetic driver of caste differentiation. Here, we tested whether Met regulates caste differentiation in honey bees by determining its effects on the caste development of bees receiving four diets: the basic, basic + 0.2% Met, basic + 0.2% Met + 20 mg/kg 5-azacytidine, and basic + 20 mg/kg 5-azacytidine. The presence of Met decreased the adult bee body length and the numbers of ovarioles, indicating that Met may direct the development of female larvae toward worker bees. The upregulated expression of SAMS, Dnmt1, and Dnmt3 caused by Met exposure in 4-d-old larvae indicated that the worker-inductive effects of Met may occur through the promotion of DNA methylation. We investigated the co-effects of Met and glucose on bee development, and found that the effects of an increased glucose level on the number of ovarioles and body length did not strengthen the worker-inductive effects caused by Met. Our results contribute to caste development theory and suggest that Met-as a methyl donor-plays a regulatory, but not decisive, role in caste differentiation.

Lifespan and healthspan benefits of exogenous H2S in C. elegans are independent from effects downstream of eat-2 mutation

Caloric restriction (CR) is one of the most effective interventions to prolong lifespan and promote health. Recently, it has been suggested that hydrogen sulfide (H2S) may play a pivotal role in mediating some of these CR-associated benefits. While toxic at high concentrations, H2S at lower concentrations can be biologically advantageous. H2S levels can be artificially elevated via H2S-releasing donor drugs. In this study, we explored the function of a novel, slow-releasing H2S donor drug (FW1256) and used it as a tool to investigate H2S in the context of CR and as a potential CR mimetic. We show that exposure to FW1256 extends lifespan and promotes health in Caenorhabditis elegans (C. elegans) more robustly than some previous H2S-releasing compounds, including GYY4137. We looked at the extent to which FW1256 reproduces CR-associated physiological effects in normal-feeding C. elegans. We found that FW1256 promoted healthy longevity to a similar degree as CR but with fewer fitness costs. In contrast to CR, FW1256 actually enhanced overall reproductive capacity and did not reduce adult body length. FW1256 further extended the lifespan of already long-lived eat-2 mutants without further detriments in developmental timing or fertility, but these lifespan and healthspan benefits required H2S exposure to begin early in development. Taken together, these observations suggest that FW1256 delivers exogenous H2S efficiently and supports a role for H2S in mediating longevity benefits of CR. Delivery of H2S via FW1256, however, does not mimic CR perfectly, suggesting that the role of H2S in CR-associated longevity is likely more complex than previously described.

Toxicological and biochemical analyses demonstrate no toxic effect of Bt maize on the Folsomia candida.

The potential effects of Bt (Bacillus thuringiensis) maize on non-target organisms must be conducted before the Bt maize is commercially planted. Folsomia candida is one of the non-target organisms of Bt maize, also as an important indicator of soil quality and environmental pollution. In this study, a 90-day F. candida feeding test were conducted to evaluate the potential effects of two Bt maize lines IE09S034 and BT799 and their non-Bt conventional isolines Zong 31 and Zheng 58. The results show that Bt maize lines had no significant effects on the survival rate, reproduction, adult body length, larval body length, and the activities of acetyl cholinesterase, catalase and superoxide dismutase on the F. candida. Namely, Bt maize had no toxic effects on the F. candida.

Redescription of Paracrobeles laterellus Heyns, 1968 (Rhabditida: Cephalobidae) from Botswana

Summary Paracrobeles laterellus is redescribed from the North-West District (Koanaka Hill), Botswana, which forms part of the Kalahari Desert. A scanning electron microscopy study of the species is presented for the first time. This population is characterised by its adult body length, lateral field with three longitudinal incisures, lips with three tines, the middle one being shorter, primary and secondary axils with two guard processes, labial probolae bifurcate with basal ridge and smooth prongs, pharynx with very swollen and elongate metacorpus, spermatheca swollen, post-vulval uterine sac well developed, vagina sigmoid, female and male tails conoid, and characters of the spicules and gubernaculum. Morphologically, P. laterellus is very similar to P. kelsodunensis and P. mojavicus according to the morphology of the lip region, i.e., with two guard processes at the primary axils and robust spicules.