Reproductive strategy of Leporinus piau (Fowler, 1941), a neotropical freshwater fish from the semi‐arid region of Brazil

This study concerns the reproductive strategy of the freshwater fish, Leporinus piau, native to the Brazilian semi‐arid region. The hypothesis of this work predicts that the species would spawn during the rainy season, presenting a seasonal reproductive strategy. The study investigated the structure of total body length and body mass, sex ratio, body size at first sexual maturity, developmental stages of gonads, fecundity, gonadosomatic index (GSI), condition factor (K) and the spawning season of L. piau. Twelve monthly samplings (mean n = 18) were carried out in 2009 and environmental parameters such as rainfall, temperature, pH, electrical conductivity and concentration of dissolved oxygen of water were registered. The sampled population of L. piau (n = 211) showed a slight predominance of males (55%), but with larger and heavier females. First sexual maturation in males occurred earlier (16.5 cm total length) than in females (20.5 cm total length). The species is a total spawner with an average fecundity of 55 000 mature oocytes. Rainfall (225 ± 7.2 mm) and concentration of dissolved oxygen (8.5 ± 0.2 mg L^?1) acted as influential factors during the spawning season. The monthly GSI shows that spawning starts when the rainy season is at its maximum and ends synchronously (females r = 0.91; males r = 0.89) with the end of the rainy season. L. piau presents a seasonal reproductive strategy with high reproductive output, providing a population increase and exploitation of the environmental resources.     

Reproductive strategy of Psectrogaster rhomboides Eigenmann & Eigenmann, 1889, a freshwater fish from Northeastern Brazil

Several environmental parameters related to the spawning season of the freshwater fish, Psectrogaster rhomboides were identified. The hypothesis predicts synchrony of the spawning season with the rainy period, presenting a seasonal reproductive strategy. This study investigated the total body length and body mass, sex ratio, body size at first sexual maturity, gonadosomatic index, condition factor, fecundity and reproductive period of P. rhomboides in the natural environment. Twelve monthly samplings (mean n = 20) were carried out from March 2009 to February 2010. Fish were captured using 4 cm diameter cast nets and environmental parameters such as rainfall, temperature, dissolved oxygen concentration, pH and electrical conductivity of the water were registered. The sampled population of P. rhomboides (n = 444) showed a sex ratio of 1 : 1. Females attained first sexual maturity at 15 cm total length and males at 15.3 cm total length. Spawning occurred from March to May, with high gonadosomatic index values during the rainy season. This species is a total spawner, with a mean fecundity of 6188 (±367) mature oocytes. P. rhomboides presents a seasonal reproductive strategy, providing a population increase and exploitation of the environmental resources during the rainy period. Rainfall (196.5 ± 4.9 mm) and the concentration of dissolved oxygen (7.82 ± 0.7018 mg L^?1) were influential factors during the spawning season. Gonadosomatic index and the condition factor were negatively correlated during the gonadal development cycle of this species. The monthly gonadosomatic index values show that spawning begins when the rainy season is at its maximum and ends synchronously (females r = 0.9171; males r = 0.889) with the end of the rainy season.     

Unravelling the genome of Holy basil: an “incomparable” “elixir of life” of traditional Indian medicine

Background

Ocimum sanctum L. (O. tenuiflorum) family-Lamiaceae is an important component of Indian tradition of medicine as well as culture around the world, and hence is known as “Holy basil” in India. This plant is mentioned in the ancient texts of Ayurveda as an “elixir of life” (life saving) herb and worshipped for over 3000 years due to its healing properties. Although used in various ailments, validation of molecules for differential activities is yet to be fully analyzed, as about 80 % of the patents on this plant are on extracts or the plant parts, and mainly focussed on essential oil components. With a view to understand the full metabolic potential of this plant whole nuclear and chloroplast genomes were sequenced for the first time combining the sequence data from 4 libraries and three NGS platforms.

Results

The saturated draft assembly of the genome was about 386 Mb, along with the plastid genome of 142,245 bp, turning out to be the smallest in Lamiaceae. In addition to SSR markers, 136 proteins were identified as homologous to five important plant genomes. Pathway analysis indicated an abundance of phenylpropanoids in O. sanctum. Phylogenetic analysis for chloroplast proteome placed Salvia miltiorrhiza as the nearest neighbor. Comparison of the chemical compounds and genes availability in O. sanctum and S. miltiorrhiza indicated the potential for the discovery of new active molecules.

Conclusion

The genome sequence and annotation of O. sanctum provides new insights into the function of genes and the medicinal nature of the metabolites synthesized in this plant. This information is highly beneficial for mining biosynthetic pathways for important metabolites in related species.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1640-z) contains supplementary material, which is available to authorized users.     

Agonistic and reproductive behaviors in males of red hybrid tilapia, Oreochromis niloticus (Linnaeus, 1758) x O. mossambicus (Peters, 1852) (Osteichthyes: Cichlidae).

The red hybrid tilapia, Oreochromis niloticus (Linnaeus, 1758) x O. mossambicus (Peters, 1852) is a fertile hybrid used in the semi-intensive level of fish culture in the Northeast of Brazil. It is a territorial cichlid and is highly aggressive towards conspecifics during the breeding season. The purpose of this study was to investigate and describe the aggressive behaviour displayed by the males of this hybrid in non-reproductive and reproductive contexts. Behavioural observations revealed that aggression displayed by the reproductive males of red hybrid tilapia included threatening, undulation, parallel, lateral and frontal attacks, chasing, escape and submission. Possession of a territory influenced male aggressiveness, which was more intense in their own territory than that observed in a neutral situation. The males built nests, irrespective of female presence. All the behavioural patterns were in accordance with those previously described for one parental species, the Nile tilapia, O. niloticus.     

Annual variation in energy reserves in male three-spined stickleback, Gasterosteus aculeatm L. (Pisces, Gasterosteidae)

Wet and dry weights of tissue were measured and concentrations of glycogen, lipid and protein were estimated for the liver, gonad and carcass of male sticklebacks from an annual population collected each month over one complete year. In young-of-the-year there is one period of rapid weight gain, in all three body regions (liver, carcass and gonads) but particularly of the carcass, in the autumn and a second in spring and early summer. This is accompanied by an increase in the water content of all three body regions. The gonadosomatic index also increases sharply in spring and early summer. Young sticklebacks accumulate lipid and glycogen slowly during the autumn and winter of their first year of life and more rapidly from late winter to early summer. Thus, the period of most rapid accumulation of these reserves coincides with the time when body weight and gonad maturation are also increasing sharply. Lipid and glycogen levels fall during the reproductive season in those males that breed, so that by July they are reduced to 43% and 37% (respectively) of their peak values in May. Levels of protein increase throughout the year as the fish grow, but in breeding males by July the concentration of protein in the carcass falls to 70% of pre-breeding levels. Breeding males therefore reach the end of the reproductive season with their total energy reserves severely reduced, and consequently they suffer a very high mortality. In contrast, adult males that fail to reproduce survive beyond the breeding season. They continue to gain weight and to accumulate lipid and glycogen from August to September, but these energy reserves fall (to levels comparable to those of post-breeding fish) in December, when these fish probably die. These results demonstrate that in male sticklebacks, growth and gonad maturation can be sustained in parallel with the accumulation of energy reserves, which are subsequently extensively depleted as a result of reproductive activities.     

Reproductive ecology of a neotropical cichlid fish,Cichla monoculus (Osteichthyes: Cichlidae)

The reproductive ecology of the freshwater fish Cichla monoculus Spix, 1831 (Osteichthyes: Cichlidae) was investigated in the Campo Grande Reservoir, Northeast Brazil. Rainfall, temperature, pH, dissolved oxygen and electrical conductivity of the water were recorded monthly. Fish collected on a monthly basis were measured, weighted, dissected, sexed and the stage of maturation of the gonads were assessed by macro and microscopic means. The semi-arid study region has short spells of rain of 2-3 months duration interspersed with dry seasons. A positive correlation was observed between rainfall and air and water temperatures and conductivity of the water. The study population had an extended spawning season, with peak reproductive activity coinciding with low water temperatures. Males were longer and heavier than females on average and were larger at onset of sexual maturity. The size frequency distributions of the oocytes indicate that C. monoculus is a multiple spawner with an estimated batch fecundity of 3100. Condition factor showed an inverse relationship in relation to gonad size during maturation in both sexes and spent fish were in poor condition. In mature males, lipid stores in the post-occipital cephalic protuberance, a secondary sexual characteristic developed during the reproductive phase, which depleted in spent individuals. The success of this fish is attributed to its reproductive capacity and to the phenotypic plasticity that allows it to adapt to the harsh ecological conditions that prevail in the semi-arid region of Northeast Brazil.     

Functional analysis of a putative holin-like peptide-coding gene in the genome of Bacillus licheniformis AnBa9

BhlA, a putative holin-like protein of Bacillus licheniformis AnBa9 expressed in Escherichia coli BL21(DE3) showed antibacterial activity against several gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and Micrococcus luteus. Deletion analysis of bhlA suggests that a hydrophobic transmembrane domain, BhlATM is essential for antibacterial activity. Though the minimum inhibitory concentration (MIC) of BhlA was sevenfold lower than BhlATM, transmembrane domain deleted construct (BhlA∆TM) had no antibacterial activity. The expression of BhlA in E. coli was found to be toxic to cells. Therefore, the bhlA was cloned in yeast surface display vector pYD1 and expressed in Saccharomyces cerevisiae. The surface displayed yeast showed inhibition of several gram-positive bacteria. This recombinant yeast expressing BhlA may be used as biodrug for efficient control of multiple drug-resistant bacterial infections.