Carmen Tamariz-Angeles

This research focused on the plant growth-promoting properties of endophytic bacteria isolated from Morisonia scabrida, a tree adapted to heat stress. Sixteen bacterial strains were isolated; among them, S1R21 tolerated 50 °C; S1H21 inhibited the growth of Fusarium sp. FH at 25 and 30 °C; and S1R16 inhibited Alternaria sp. ATCC20084 and F. oxysporum CTLM12 at 25 and 30 °C. Regarding enzymatic activities, S1R21 exhibited amylase activity at 30 °C; S1T20 showed proteinase activity at 37 °C; S1T11 showed pectinase activity at 37 °C; S1R16 and S1R9 demonstrated lipase activity; and S1R20 showed CMCase activity at 30 °C. S1T1 solubilized tricalcium phosphate at 25 and 30 °C; S1H5 produced siderophores at 30 °C; and S1T11 produced IAA and fixed nitrogen at 30 and 37 °C. With respect to germination percentage of corn and alfalfa, the highest values were achieved with strain S1R21 at 30 and 37 °C. Seven strains were selected and identified by 16S rDNA analysis as Bacillus albus S1H21, Bacillus cereus S1R21, Lysinibacillus fusiformis S1R9, Enterobacter sp. (S1H5 and S1R8), Klebsiella sp. S1R16 and Stutzerimonas stutzeri S1T11. Most of these strains increased growth parameters of Zea mays and Medicago sativa, with Stutzerimonas stutzeri S1T11 standing out regarding high aerial and root length, as well as fresh and dry weight. This research study is one of the few studies on endophytic bacteria associated with the Morisonia scabrida tree. It demonstrates that its bacterial diversity could contribute to various biological roles, such as that of plant growth promoter under heat stress.

Peperomia hartwegiana is a high Andean medicinal plant popularly called“congona redonda”. It is used to cure inflammations and some infectious diseases, andit is marketed in the popular market from Huaraz. Then, it was collected some samplesof P. hartwegiana at the Challhua folkloric market and stored in refrigeration in paperbags before their histological cuts. The organs studied were leaves, floriferous axis,stem, and adventitious roots. Freehand histological cut was performed for all organs,and samples obtained were colored with safranine. Hence, lugol was used to colorthe stems. The results obtained show that P. hartwegiana is a herbaceous species withadventitious roots and oval, verticillate, and succulent leaves. Its inflorescence forms acharacteristic terminal spike. Anatomically, the leaves have multicellular hairs in bothepidermis layers. The adaxial epidermis is multiseriate where cells store water, whilethe abaxial epidermis is uniseriate with stomata. Between both epidermis layers, themesophyll comprises lacunar and palisade chlorophyll parenchyma. The floriferousaxis has a uniseriate epidermis on a lacunar collenchyma delimited by fundamentalparenchyma, and their vascular bundle forms an atactostele. The stem has a uniseriateepidermis with the presence of elongated multicellular hairs. Likewise, it has a lacunarcollenchyma that delimits a fundamental parenchyma that surrounds the conductingbeams that form an atactostele. The adventitious root presents primary developmentwith the presence of a cortical parenchyma, the vascular bundles form a radicularanatomic structure polyarch with primary phloem and xylem axes alternated.

Endophytic bacteria found in marine macroalgae have been studied for their potential antimicrobial activity, consequently, they could serve as a valuable source of bioactive compounds to control pathogenic bacteria, yeasts, and fungi. Algae endophytic bacteria were isolated from Caulerpa sp., Ulva sp., Ahnfeltiopsis sp., and Chondracantus chamissoi from Yacila and Cangrejo Beaches (Piura, Peru). Antimicrobial assays against pathogenic bacteria were evaluated using cross-culture, over-plate, and volatile organic compound tests. Afterward, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of selected crude extracts were determined, also ITS molecular analysis, antifungal activity, and PCR of iturin, fengycin, and surfactin genes were performed for bacteria strains exhibiting better activity. Forty-six algae endophytic bacteria were isolated from algae. Ten strains inhibited gram-positive pathogenic bacteria (Enterococcus faecalis, Staphylococcus epidermidis, S. aureus, and Listeria monocytogenes), and 12 inhibited gram-negative bacteria (Escherichia coli and Salmonella enteric sv typhimurium). Bacteria with better activity belong to Bacillus sp., Kluyvera ascorbata, Pantoea agglomerans, Leclercia adecarboxylata, and Enterobacter sp., which only four showed antifungal activities against Candida albicans, C. tropicalis, Colletotrichium sp., Fusarium sp., Fusarium oxysporum, and Alternaria sp. Furthermore, K. ascorbata YAFE21 and Bacillus sp. YCFE4 exhibited iturin and fengycin genes. The results indicate that the algae endophytic bacteria found in this study, particularly K. ascorbata YAFE21, Bacillus sp. YCFR6, L. adecarboxylata CUFE2, Bacillus sp. YUFE8, Enterobacter sp. YAFL1, and P. agglomerans YAFL6, could be investigated as potential producers of antimicrobial compounds due to their broad activity against various microorganisms.

Ten new thiosemicarbazone derivatives, furan-2-carbaldehyde thiosemicarbazone (1), 3-methyl-furan-2-carbaldehyde thiosemicarbazone (2), 5-hydroxymethyl-furan-2-carbaldehyde thiosemicarbazone (3), 5-trifluoromethyl-furan-2-carbaldehyde thiosemicarbazone (4), 5-nitro-furan-2-carbaldehyde thiosemicarbazone (5), 5-phenyl-furan-2-carbaldehyde thiosemicarbazone (6), 5-(2-fluorophenyl)-furan-2-carbaldehyde thiosemicarbazone (7), 5-(4-methoxyphenyl)-furan-2-carbaldehyde thiosemicarbazone (8), 5-(1-naphthyl)-furan-2-carbaldehyde thiosemicarbazone (9), and 5-(1H-Pyrazol-5-yl)-furan-2-carbaldehyde thiosemicarbazone (10) were synthesized by condensing thiosemicarbazide with the respective furan-2-carbaldehyde in methanol. The prepared compounds were characterized by spectroscopic studies (FT-IR and NMR) and electrospray mass spectrometry. The molecular structures of 2, 6, 7, and 8 have also been determined by X-ray crystallography. Compounds 2, 6, and 7 crystallize in the E conformation about the N1-C6, N1-C11, and N1-C11 bonds, respectively, while 8 adopts the Z conformation about the N1-C12 bond with the presence of an intramolecular N2-HO2 hydrogen bond. All prepared thiosemicarbazone derivatives were evaluated for their in vitro antibacterial, antifungal, and antitumor activities against Staphylococcus aureus strains, Candida albicans/Candida tropicalis fungi, and seven human tumor cell lines (HuTu80, H460, DU145, M-14, HT-29, MCF-7, and LNCaP), respectively. The antioxidant activity was also studied by the DPPH assay. Compound 5 exhibited significant antibacterial activity against Staphylococcus aureus ATCC700699 (MIC=1μg/mL) compared to the nitrofurantoin and gentamicin reference drugs (MIC=125 and 10->100μg/mL, respectively). Compound 4 was ten times less active than amphotericin B (MIC=5μg/mL) against Candida albicans (ATCC90028 and ATCC10231), while 1 exhibited a moderate effect of scavenging of DPPH radical (IC₅₀=40.9μg/mL) in comparison to ascorbic acid reference compound (IC₅₀=22.0μg/mL). Among all the studied thiosemicarbazones, 5 showed a higher cytotoxic activity (IC₅₀=13.3627.73μ) in relation to the other tested compounds (IC₅₀=34.84>372.34μ) against all tested cell lines, except the LNCaP cell line, exhibiting its highest antiproliferative activity (IC₅₀=13.36μ) on the HuTu80cell line. Besides, 8 and 9 exhibited high antitumor activity (IC₅₀=13.31 and 7.69μ, respectively) against the LNCaP cells.

Se aislaron cepas de bacterias provenientes de tres tipos de muestras: agua fresca, cebos enriquecidos in situ y ex situ. Se prepararon diluciones seriadas y el cultivo fue a 50 °C usando un medio Salino-Basal. Las cepas aisladas fueron tamizadas para las actividades endoglucanasa y xilanasa con métodos cualitativos (Rojo Congo) y cuantitativos (DNS). Se usó el análisis molecular 16S rDNA para la identificación taxonómica. Se aislaron 31 cepas, de las cuales 14 mostraron actividades hidrolíticas y pertenecían a Bacillus subtilis y Bacillus licheniformis. Además, B. subtilis DCH4 mostró la mayor actividad endoglucanasa a 45 °C y pH 5, y xilanasa a 55 °C y pH 6. Entonces, DCH4 se cultivó por fermentación sumergida con dos medios diferentes suplementado con bagazo de caña de azúcar, paja de trigo o tallo de quinua para evaluar su capacidad de sacarificación. También, se exploraron los genes de xilanasa y celulasa mediante cebadores específicos; los amplicones obtenidos fueron secuenciados y analizados. Se encontró que los extractos enzimáticos de DCH4 preparados con bagazo de caña o tallos de quinua mostraron las actividades endoglucanasa y xilanasa más elevadas. De acuerdo a los análisis moleculares de los genes involucrados en el proceso hidrolítico, las actividades de endoglunacasa y xilanasa exhibidas por DCH4 podrían atribuirse a una celulasa bifuncional conformada por una endo-beta-1,4-glucanasa (GH5) unida al dominio celulosa 3 (CBM3), y una endo-1,4-beta-xilanasa (GH11), respectivamente. Posteriores experimentos transcriptómicos podrían ser considerados para lograr estrategias de optimización para la producción de biocombustibles a partir de biomasa lignocelulósica.

EFECTO DE LOS REGULADORES DE CRECIMIENTO VEGETAL EN LA MULTIPLICACIÓN Y ENRAIZAMIENTO IN VITRO DE SENECIO CALVUS (ASTERACEAE), PLANTA MEDICINAL ALTOANDINA, ENDÉMICA DEL PERÚ